"uuid","repository link","title","author","contributor","publication year","abstract","subject topic","language","publication type","publisher","isbn","issn","patent","patent status","bibliographic note","access restriction","embargo date","faculty","department","research group","programme","project","coordinates"
"uuid:21e5b9c2-3e58-495c-881c-634e67ebe645","http://resolver.tudelft.nl/uuid:21e5b9c2-3e58-495c-881c-634e67ebe645","Sensitivities and where to find them: Domain shift robustness, attacks, and training variations in visual learning","Wang, Z. (TU Delft Pattern Recognition and Bioinformatics)","Reinders, M.J.T. (promotor); van Gemert, J.C. (promotor); Loog, M. (promotor); Delft University of Technology (degree granting institution)","2024","Machine learning aims to solve a task with a certain algorithm or statistical model that is trained on data, with or without labels. As a subcategory of machine learning, deep learning achieves good performance with its flexibility on end-to-end representation learning and architecture design. Despite the successes of deep learning, the output of which can be sensitive to various factors. This work visits three sensitivity factors: distribution shifts, attacks, and human impact.
One factor that can impair the performance of a deep net is a distribution shift between the training data and the test data. Depending on the availability of either data or label, some coping strategies for distribution shifts are domain adaptation, domain generalization, transfer learning and multi-domain learning. We first show how domain adaptation can help to mitigate the gap between historic and modern photos for visual place recognition. We show that this can be realized by focusing the network on the buildings rather than the background with an attention module. In addition, we introduce a domain adaptation loss to align the source domain and the target domain. We thenmove to domain generalization and show that learning domain invariant representations cannot lead to good performance for domain generalization. We suggest to relax the constraint of learning domain invariant representation by learning representations that guarantee a domain invariant posterior, but the resulting representations are not necessarily domain invariant. We coin this type of representation as hypothesis invariant representation. Finally, we study multi-domain learning and transfer learning with the application of deep learning to classify Parkinson’s disease. We show that a temporal attention mechanism is key for transferring useful information from large non-medical public video datasets to Parkinson videos. Weights are learned for various tasks involved in this Parkinson dataset to decide a final score for each single patient.
A deep net is also sensitive to malicious attacks, e.g., adversarial classification attacks or explanation attacks. Adversarial classification attacks manipulate the classification result while explanation attacks change the explanation heatmap but do not alter the original classification results. We notice that the robustness to an adversarial classification attack is linked to the shape of the softmax function and can be improved by using a polynomial softRmax, which is based on a Cauchy class conditional distribution. This also shows that the performance of deep learning is sensitive to the choice of class conditional distribution. Regarding the explanation attacks, we design several ways to attack the GradCAM explanation heatmap to become a predetermined target explanation which does not explain the classification result.
We further explore the influence of human trainers in hyperparameter tuning during the learning of deep nets. A user study is designed to explore the correlation between the performance of a network and the human trainer’s experience of deep learning. Experience of deep learning is found to be correlated with the performance of the deep net.","","en","doctoral thesis","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:2889190d-9664-4f89-99fa-79bbccffa049","http://resolver.tudelft.nl/uuid:2889190d-9664-4f89-99fa-79bbccffa049","Timing, Indicators, and Approaches to Digital Patient Experience Evaluation: Umbrella Systematic Review","Wang, T. (TU Delft Applied Ergonomics and Design); Giunti, Guido (TU Delft Applied Ergonomics and Design; Trinity College Dublin); Goossens, R.H.M. (TU Delft Human-Centered Design; TU Delft Applied Ergonomics and Design); Melles, M. (TU Delft Applied Ergonomics and Design)","","2024","BACKGROUND: The increasing prevalence of DH applications has outpaced research and practice in digital health (DH) evaluations. Patient experience (PEx) was reported as one of the challenges facing the health system by the World Health Organization. To generate evidence on DH and promote the appropriate integration and use of technologies, a standard evaluation of PEx in DH is required. OBJECTIVE: This study aims to systematically identify evaluation timing considerations (ie, when to measure), evaluation indicators (ie, what to measure), and evaluation approaches (ie, how to measure) with regard to digital PEx. The overall aim of this study is to generate an evaluation guide for further improving digital PEx evaluation. METHODS: This is a 2-phase study parallel to our previous study. In phase 1, literature reviews related to PEx in DH were systematically searched from Scopus, PubMed, and Web of Science databases. Two independent raters conducted 2 rounds of paper screening, including title and abstract screening and full-text screening, and assessed the interrater reliability for 20% (round 1: 23/115 and round 2: 12/58) random samples using the Fleiss-Cohen coefficient (round 1: k1=0.88 and round 2: k2=0.80). When reaching interrater reliability (k>0.60), TW conducted the rest of the screening process, leaving any uncertainties for group discussions. Overall, 38% (45/119) of the articles were considered eligible for further thematic analysis. In phase 2, to check if there were any meaningful novel insights that would change our conclusions, we performed an updated literature search in which we collected 294 newly published reviews, of which 102 (34.7%) were identified as eligible articles. We considered them to have no important changes to our original results on the research objectives. Therefore, they were not integrated into the synthesis of this review and were used as supplementary materials. RESULTS: Our review highlights 5 typical evaluation objectives that serve 5 stakeholder groups separately. We identified a set of key evaluation timing considerations and classified them into 3 categories: intervention maturity stages, timing of the evaluation, and timing of data collection. Information on evaluation indicators of digital PEx was identified and summarized into 3 categories (intervention outputs, patient outcomes, and health care system impact), 9 themes, and 22 subthemes. A set of evaluation theories, common study designs, data collection methods and instruments, and data analysis approaches was captured, which can be used or adapted to evaluate digital PEx. CONCLUSIONS: Our findings enabled us to generate an evaluation guide to help DH intervention researchers, designers, developers, and program evaluators evaluate digital PEx. Finally, we propose 6 directions for encouraging further digital PEx evaluation research and practice to address the challenge of poor PEx.","digital health; eHealth; evaluation approaches; evaluation indicators; evaluation timing; human-computer interaction; mHealth; mobile health; mobile phone; patient experience; patient-centered care; telemedicine; user experience; user-centered design","en","review","","","","","","","","","","Human-Centered Design","Applied Ergonomics and Design","","",""
"uuid:538af6ba-2ff0-477b-886f-9ad68d63ee04","http://resolver.tudelft.nl/uuid:538af6ba-2ff0-477b-886f-9ad68d63ee04","Towards a Reliable Design of Geopolymer Concrete for Green Landscapes: A Comparative Study of Tree-Based and Regression-Based Models","Wang, Ranran (Guangzhou University); Zhang, Jun (Guangzhou University); Lu, Yijun (Guangzhou University); Ren, S. (TU Delft Pavement Engineering); Huang, Jiandong (Guangzhou University)","","2024","The design of geopolymer concrete must meet more stringent requirements for the landscape, so understanding and designing geopolymer concrete with a higher compressive strength challenging. In the performance prediction of geopolymer concrete compressive strength, machine learning models have the advantage of being more accurate and faster. However, only a single machine learning model is usually used at present, there are few applications of ensemble learning models, and model optimization processes is lacking. Therefore, this paper proposes to use the Firefly Algorithm (AF) as an optimization tool to perform hyperparameter tuning on Logistic Regression (LR), Multiple Logistic Regression (MLR), decision tree (DT), and Random Forest (RF) models. At the same time, the reliability and efficiency of four integrated learning models were analyzed. The model was used to analyze the influencing factors of geopolymer concrete and determine the strength of their influencing ability. According to the experimental data, the RF-AF model had the lowest RMSE value. The RMSE value of the training set and test set were 4.0364 and 8.7202, respectively. The R value of the training set and test set were 0.9774 and 0.8915, respectively. Therefore, compared with the other three models, RF-AF has a stronger generalization ability and higher prediction accuracy. In addition, the molar concentration of NaOH was the most important influencing factors, and its influence was far greater than the other possible factors including NaOH content. Therefore, it is necessary to pay more attention to NaOH molarity when designing geopolymer concrete.","ensemble learning model; beetle antennae search; geopolymer concrete; NaOH molarity","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:a67ddc88-90a3-4cd6-8da1-f40d630644f3","http://resolver.tudelft.nl/uuid:a67ddc88-90a3-4cd6-8da1-f40d630644f3","Investigating the Role of Executive Intrafirm Alumni Networks in Top Management Fraud: Multilevel Study in China's Construction Industry","Wang, Ran (Hunan University); Wang, Tongbing (Hunan University); Lee, Chia-Jung (Tunghai University); Liu, Zhengxuan (TU Delft Design & Construction Management; Hunan University); Zhang, G. (Hunan University)","","2024","To explore factors that influence the likelihood of committing fraud in the construction industry, this study concentrated on senior executives and tested whether some characteristics at the individual and firm levels have impacts on the likelihood of fraud committed by top management. Based on social network theory, this study first proposes that intrafirm alumni networks may increase the probability of senior executives engaging in corrupt behavior. Then the study explored whether the effect of executives' alumni networks on their wrongdoings is influenced by external and internal corporate governance measures. To verify the hypotheses, this study collected data on 2,017 senior executives from 118 construction companies in China from 2013 to 2021. Because of the multilevel structure of the data, hierarchical linear modeling was used. The results show that alumni networks have a significant positive effect on top management fraud. The effect is weakened by external auditing, altered by board independence, and strengthened by the size of the board of directors and the size of the supervisory board. This multilevel research contributes to advancing the understanding of managers' fraudulent behavior within an organization and extends the literature on social networks and corporate governance in the construction industry.","Alumni networks; Corporate governance; Hierarchical linear modeling; Social networks; Top management fraud","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-13","","","Design & Construction Management","","",""
"uuid:4044dca9-7a65-444b-b733-31c8d11a4d8e","http://resolver.tudelft.nl/uuid:4044dca9-7a65-444b-b733-31c8d11a4d8e","Optimal Control for Distributed Aeroelastic Morphing Structure with Uncertainties and Imperfections","Mkhoyan, T. (TU Delft Arts & Crafts); Wang, Xuerui (TU Delft Group Wang); De Breuker, R. (TU Delft Group De Breuker)","","2024","This research takes a further step towards the development of an autonomous aeroservoelastic wing concept with distributed flaps. The wing demonstrator, developed within the TU Delft SmartX project, aims to demonstrate in-flight performance optimization and multi-objective control using an over-actuated wing design. To address the challenges posed by the aeroelastic system's nonlinearities and uncertainties, this paper employs an optimal control method relying on solving the State-Dependent Riccati Equation (SDRE). Geometrical nonlinearities, introduced in the form of plunge and torsion stiffness, make the system state-dependent and unsuitable for linear control methods. Additionally, a backlash model is incorporated to represent the uncertainty of the actuation system. The control strategy is implemented in a multi-objective manner to perform maneuver and gust load alleviation while accounting for the nonlinearities and uncertainties using the SDRE control. Firstly, a numerical sample case is investigated involving a state-dependent and highly non-linear canard aircraft configuration, to assess the ability of the SDRE control method. Then, in a numerical experiment, the effectiveness of the control strategy is evaluated through the nonlinear aeroelastic model. Evaluations are made on the practicality of the control approach, laying a foundation for future static and dynamic wind tunnel experiments with the SmartX-Neo","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Arts & Crafts","","",""
"uuid:aeed12d4-3bde-4d73-a825-258aa615b5b5","http://resolver.tudelft.nl/uuid:aeed12d4-3bde-4d73-a825-258aa615b5b5","Approaching nearly zero energy of PV direct air conditioners by integrating building design, load flexibility and PCM","Li, Sihui (Changsha University of Science and Technology); Peng, Jinqing (Hunan University); Wang, Meng (Changsha University of Science and Technology); Wang, Kai (Hunan University); Li, Houpei (Hunan University); Lu, C.J. (TU Delft Environmental & Climate Design)","","2024","The energy matching of PV driven air conditioners is influenced by building load demand and PV generation. Merely increasing energy performance of building or PV capacity separately may improve the energy balance on a large time resolution, the real-time energy mismatching problem is still serious. In this study, a coordinated optimization method of PV capacity, building design, and load flexibility is proposed for improving the real-time energy matching of PVAC system. Then, a methodology integrating data mining method (XG Boost) and parametric simulation was developed to identify the determinant parameters of PV system and building design, exploring feature importance and correlations. The results of XG Boost indicate that the PV capacity, shape factor, and SHGC are the most critical factors. Finally, based on the optimized building design, the PCM layer was applied to improve the real time energy matching. To achieve a goal of 90 % ZEP, the PCM capacity can be decreased by 50.4 % and 62.8 % in Guangzhou and Shanghai in the optimized building. Moreover, the PV capacity can be reduced by 23 % in Guangzhou. The findings of this study provide practical guidance for designing PVAC system coupling with building design and energy storage devices.","PV direct driven air conditioner (PVAC); Zero energy buildings; Load flexibility; Building design","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-15","","","Environmental & Climate Design","","",""
"uuid:e18134a3-5359-4e10-b49b-303085dcbad7","http://resolver.tudelft.nl/uuid:e18134a3-5359-4e10-b49b-303085dcbad7","Interference Mitigation for Automotive FMCW Radar Based on Contrastive Learning With Dilated Convolution","Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Li, Runlong (Beijing University of Posts and Telecommunications); Zhang, Xinqi (Beijing University of Posts and Telecommunications); He, Yuan (Beijing University of Posts and Telecommunications)","","2024","As one of the crucial sensors for environment sensing, frequency modulated continuous wave (FMCW) radars are widely used in modern vehicles for driving assistance/autonomous driving. However, the limited frequency bandwidth and the increasing number of equipped radar sensors would inevitably cause mutual interference, degrading target detection and producing safety hazards. In this paper, a deep learning-based interference mitigation (IM) approach is proposed for FMCW radars by using the dilated convolution for network construction and a designated contrast learning strategy for training. The dilated convolution enlarges the receptive field of the neural network, and the designated contrastive learning strategy enforces to distinguish better between interferences and desired signals. The results of numerical simulation and experimental data processing show that the dilated convolution-based IM network, compared to the traditional convolution-based ones, can achieve a higher Signal-to-Interference-plus-Noise-Ratio (SINR) and target detection rate. Moreover, the designated contrastive learning strategy enables a better and more stable IM performance without increasing the complexity of the network, which can facilitate faster signal processing.","Automotive radar; interference mitigation; deep learning; dilated convolution; contrastive learning","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-31","","","Microwave Sensing, Signals & Systems","","",""
"uuid:30d594bf-5ee1-4d25-b7a4-c8e4b4615ce0","http://resolver.tudelft.nl/uuid:30d594bf-5ee1-4d25-b7a4-c8e4b4615ce0","A Resilience Enhanced Secondary Control for AC Micro-grids","Xiao, J. (TU Delft DC systems, Energy conversion & Storage); Wang, L. (TU Delft Hydraulic Structures and Flood Risk); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2024","Communication-based distributed secondary control is deemed necessary to restore the state of islanding AC microgrids to set points. As its limited global information, the microgrids become vulnerable to cyber-attacks, which by falsifying the communicating singles, like the angular frequency, can disturb the power dispatch in the microgrids or even induce blackout by pushing the microgrids beyond the safe operation area and triggering the protection. To make the microgrids more cyber secure, adaptive resilient control for the secondary frequency regulation is proposed. It assumes that each converter is communicating with its adjacent converters. With the proposed control, the weight of the communication channel being attacked is automatically reduced, and the more the communicating signals are falsified, the further the weight of that communication channel is weakened. The proposed approach does not rely on attack detection and thereby is easy to implement; Besides, it still works when challenged by a combination of multi-attack signals; Moreover, it applies to multiple communication lines getting attacked cases. Finally, the effectiveness and feasibility of the proposed resilient control scheme are validated by both simulations and experimental results.","AC micro-grid; adaptive control; Communication networks; cyber-attack; Cyberattack; distributed control; Frequency control; Microgrids; Power system stability; Resilience; Voltage control","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-04","","","DC systems, Energy conversion & Storage","","",""
"uuid:211d9fc2-aab8-455b-85e8-b3328e2b930a","http://resolver.tudelft.nl/uuid:211d9fc2-aab8-455b-85e8-b3328e2b930a","Influence of Scour Protection on the Vertical Bearing Behaviour of Monopiles in Sand","Li, Qiang (Hangzhou City University; PowerChina Huadong Engineering Corporation Limited); Wang, Xinquan (Hangzhou City University); Gavin, Kenneth (TU Delft Geo-engineering); Jiang, Shengxiang (PowerChina Huadong Engineering Corporation Limited); Diao, Hongguo (Hangzhou City University); Wang, Kangyu (Zhejiang University of Technology)","","2024","Extensive studies have been performed on the effectiveness of scour protection against scour erosion progression. But there is little research to date evaluating the effect of scour protection on vertical resistance behaviour of monopile foundations. This paper investigates the influence of scour protection on the vertical loading behaviour of monopiles installed in sand using centrifuge tests and finite element analysis (FEA). Four scour protection widths (1D, 2D, 3D, 4D; where D is the pile diameter) and three scour protection thicknesses (1 m, 2 m, 3 m) were modelled on a pile with a slenderness ratio (L/D) of five. In the FEA, the scour protection mechanism was modelled using two strategies, namely the ‘stress method’ by applying stress and the ‘material method’ by applying virtual material on the seabed surface around the pile. Outcomes between these two strategies were compared, and the contact coefficient δ used in the ‘material method’ for describing the contact effectiveness of the overlaying scour protection material with the pile structure was introduced, providing a more scientific and accurate calculation reference for engineering applications. The results indicated that the vertical capacity of monopiles could be increased by 5% to 23% by adopting the scour protection measure, depending on the scour protection width and scour protection thickness.","piles and piling; scour protection; vertical resistance; finite element methods; centrifuge modelling","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:d69ee37f-6416-4a5b-9244-77b3bef2f110","http://resolver.tudelft.nl/uuid:d69ee37f-6416-4a5b-9244-77b3bef2f110","Scour Effect on the Lateral Bearing Behaviour of Monopiles Considering Different Slenderness Ratios","Li, Qiang (Hangzhou City University; PowerChina Huadong Engineering Corporation Limited); Wang, Xinquan (Hangzhou City University); Gavin, Kenneth (TU Delft Geo-engineering); Jiang, Shengxiang (PowerChina Huadong Engineering Corporation Limited); Diao, Hongguo (Hangzhou City University); Wang, Mingyuan (PowerChina Huadong Engineering Corporation Limited); Wang, Kangyu (Zhejiang University of Technology)","","2024","Scour leads to the loss of soil around monopile foundations for offshore wind turbines, which affects their structural safety. In this paper, the effect of scour on the lateral behaviour of monopiles was extensively investigated using finite element analysis, and calibration and comparison were undertaken using centrifuge tests. Piles with three slenderness ratios, i.e., 3, 5 and 8, were studied by keeping the diameter constant and varying the embedment length. Three scour types (local narrow, local wide and global) and four scour depths (0.5D, 1D, 1.5D and 2D; D signifies the pile diameter) were considered in this investigation. The results indicate that the lateral resistance of the pile is the greatest in the case of local narrow scour, followed by that in the cases of local wide scour and global scour. When the scour depth is larger than 1D, the influence of the scour type on the pile lateral bearing behaviour is insignificant. The influence of the scour type and scour depth on the pile lateral bearing behaviour is broadly similar for piles with slenderness ratios of 3, 5 and 8. However, the piles featured with smaller embedment lengths show a larger decrease rate in their lateral capacity, which means the effect of scour should cause more concern on small slenderness ratio monopiles.","piles and piling; scour; finite element methods; centrifuge modelling; lateral bearing behaviour","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:935cc7ae-158a-4b98-a142-f2ec0240a768","http://resolver.tudelft.nl/uuid:935cc7ae-158a-4b98-a142-f2ec0240a768","Recycling of Aluminosilicate-Based Solid Wastes through Alkali-Activation: Preparation, Characterization, and Challenges","Feng, Lichao (Jiangsu Ocean University); Yi, Shengjie (Jiangsu Ocean University); Zhao, Shuyuan (Harbin Institute of Technology); Zhong, Qiucheng (Jiangsu Ocean University); Ren, Feirong (Jiangsu Ocean University); Liu, C. (TU Delft Materials and Environment); Zhang, Y. (TU Delft Materials and Environment); Wang, Wenshou (University of Jinan); Li, Zhenming (University of Sheffield)","","2024","Recycling aluminosilicate-based solid wastes is imperative to realize the sustainable development of constructions. By using alkali activation technology, aluminosilicate-based solid wastes, such as furnace slag, fly ash, red mud, and most of the bio-ashes, can be turned into alternative binder materials to Portland cement to reduce the carbon footprint of the construction and maintenance activities of concrete structures. In this paper, the chemistry involved in the formation of alkali-activated materials (AAMs) and the influential factors of their properties are briefly reviewed. The commonly used methods, including X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG), nuclear magnetic resonance spectroscopy (NMR), and X-ray pair distribution function technology, to characterize the microstructure of AAMs are introduced. Typical characterization results of AAMs are shown and the limitations of each method are discussed. The main challenges, such as shrinkage, creep, efflorescence, carbonation, alkali–silica reaction, and chloride ingress, to conquer for a wider application of AAMs are reviewed. It is shown that several performances of AAMs under certain circumstances seem to be less satisfactory than traditional portland cement systems. Existing strategies to improve these performances are reviewed, and recommendations for future studies are given.","slag; fly ash; alkali-activation; microstructure; performance; challenges","en","review","","","","","","","","","","","Materials and Environment","","",""
"uuid:58f5f372-b9f6-4c80-8bdc-1188c05a9894","http://resolver.tudelft.nl/uuid:58f5f372-b9f6-4c80-8bdc-1188c05a9894","TAIS: Transparent Amplifying Intelligent Surface for Indoor-To-Outdoor mmWave Communications","Liu, Bin (Katholieke Universiteit Leuven); Wang, Q. (TU Delft Embedded Systems); Pollin, Sofie (Katholieke Universiteit Leuven)","","2024","This paper presents a novel transparent amplifying intelligent surface (TAIS) architecture for uplink enhancement in indoor-To-outdoor mmWave communications. The TAIS is an amplifier-based transmissive intelligent surface that can refract and amplify the incident signal, instead of only refracting it with adjustable phase shift by most passive reconfigurable intelligent surfaces (RIS). With advanced indium tin oxide film and printing technology, TAIS can be fabricated on the windows without any visual effects. This paper primarily focuses on exploiting the TAIS-based architecture to boost the uplink spectral efficiency (SE) in indoor-To-outdoor mmWave communications. By jointly optimizing the TAIS's phase shift matrix and transmit power of the user equipment, the uplink SE can be maximized by exploiting the nonlinearity in the TAIS's amplification process. The key enabler is that we drive the optimal phase shift matrix that maximizes the SE and deduces its closed-form representation. The SE maximization is then proved to be transferred to the transmit power optimization problem. Another important enabler is that we design a low-complexity algorithm to solve the optimization problem using the difference of convex programming. Moreover, the asymptotic spectral efficiency under nonlinear amplification and power scaling law with infinitely large elements under both the sparse and rich scattering channel models are analyzed. Simulation results show that our proposed TAIS can increase the SE by up to 24.7% as compared to its alternative methods.","indoor-To-outdoor communication; mmWave MIMO; nonlinear amplification; Reconfigurable intelligent surface (RIS); spectral efficiency; transparent amplifying intelligent surface (TAIS)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-03","","","Embedded Systems","","",""
"uuid:640c0f3e-60c4-4736-ae08-352bef953637","http://resolver.tudelft.nl/uuid:640c0f3e-60c4-4736-ae08-352bef953637","On the post-impact fatigue behavior and theoretical life prediction of CF/PEEK-titanium hybrid laminates using an energy dissipation approach","Ji, C. (TU Delft Structural Integrity & Composites; Harbin Institute of Technology); Hu, Jiqiang (Harbin Institute of Technology); Alderliesten, R.C. (TU Delft Structural Integrity & Composites); Yang, Jinchuan (Harbin Institute of Technology); Zhou, Zhengong (Harbin Institute of Technology); Sun, Yuguo (Harbin Institute of Technology); Wang, Bing (Harbin Institute of Technology)","","2024","This paper aims to illustrate the effect of the impact damage on fatigue behavior of CF/PEEK-titanium hybrid laminates. To achieve this end, a fatigue life model was proposed to predict the S–N curves of the laminates at various initial impact energy levels and stress ratios based on the energy dissipation approach. The energy dissipation behavior of the laminates during fatigue loading under different experimental conditions was analyzed through a large amount of post-impact fatigue tests, and the correlation between the initial impact damage and the total fatigue dissipation energy was determined. The full-field axial strain distribution of the titanium layer on the impacted side of the laminate was characterized in terms of initial impact energy level and maximum stress using digital image correlation, and then the post-impact fatigue failure mechanism of CF/PEEK-Ti hybrid laminates was summarized. Finally, the validity of the proposed model was verified by fatigue tests under other conditions of stress ratio and impact energy level. It is worth mentioning that the proposed model is also applicable to other types of FMLs, and can accurately predict the residual fatigue life of laminates after impact with only one set of S–N curve data.","Energy dissipation approach; Fiber metal laminates; Life prediction; Post-impact fatigue behavior","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-03","","","Structural Integrity & Composites","","",""
"uuid:4c4e19f9-87a1-435d-81bd-9ab5e43bea05","http://resolver.tudelft.nl/uuid:4c4e19f9-87a1-435d-81bd-9ab5e43bea05","Impact of fast-solidification on all-d-metal NiCoMnTi based giant magnetocaloric Heusler compounds","Zhang, F. (TU Delft RST/Fundamental Aspects of Materials and Energy; City University of Hong Kong); Wu, Z. (TU Delft RST/Fundamental Aspects of Materials and Energy); Wang, Jianlin (Chinese Academy of Sciences); Wu, Zhenduo (City University of Hong Kong); Zhao, C. (TU Delft RST/Storage of Electrochemical Energy); Eijt, S.W.H. (TU Delft RST/Fundamental Aspects of Materials and Energy); Schut, H. (TU Delft RST/Neutron and Positron Methods in Materials); van Dijk, N.H. (TU Delft RST/Fundamental Aspects of Materials and Energy); Brück, E.H. (TU Delft RST/Fundamental Aspects of Materials and Energy)","","2024","Recently, the all-d-metal Ni(Co)MnTi based Heusler compounds are found to have a giant magnetocaloric effect (GMCE) near room temperature and manifest different functionalities like multicaloric effects, which can be employed for solid-state refrigeration. However, in comparison to other traditional Heusler compounds, the relatively large thermal hysteresis (ΔThys) and moderately steep ferromagnetic phase transition provides limitations for real applications. Here, we present that fast solidification (suction casting) can sufficiently tailor the GMCE performance by modifying the microstructure. Compared with the arc-melted sample, the magnetic entropy change of the suction-casted sample shows a 67% improvement from 18.4 to 29.4 Jkg−1K−1 for a field change (∆μ0H) of 5 T. As the thermal hysteresis has maintained a low ΔThys value (5.5 K) for the enhanced first-order phase transition, a very competitive reversible magnetic entropy change of 21.8 Jkg−1K−1 for ∆μ0H = 5 T is obtained. Combining high-resolution transmission electron microscopy (HRTEM) and positron annihilation spectroscopy (PAS) results, the difference in lattice defect concentration is found to be responsible for the significant improvement in GMCE for the suction-cast sample, which suggests that defect engineering can be applied to control the GMCE. Our study reveals that fast solidification can effectively regulate the magnetocaloric properties of all-d-metal NiCoMnTi Heusler compounds without sacrificing ΔThys.","All-d-metal Heusler compounds; Lattice defects; Magnetocaloric effect; Ni-Co-Mn-Ti","en","journal article","","","","","","","","","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:740ae19e-044a-4bb1-80c8-0c3da244b184","http://resolver.tudelft.nl/uuid:740ae19e-044a-4bb1-80c8-0c3da244b184","Dynamic risk assessment of chemical process systems using the System-Theoretic accident model and process approach (STAMP) in combination with cascading failure propagation model (CFPM)","Sun, Hao (Anhui University of Technology); Wang, Haiqing (China University of Petroleum (East China)); Yang, M. (TU Delft Safety and Security Science; Universiti Teknologi Malaysia); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Universiteit Antwerpen; Katholieke Universiteit Leuven)","","2024","To maintain continuous production, chemical plant operators may ignore faults or handle faults online rather than shutting down process systems. However, interaction and interdependence links between components in a digitalized process system are substantial. Thus, faults will be propagated to downstream nodes, potentially leading to risk accumulation and major accidents. However, limited attention has been paid to this type of risk. To model the risk accumulation process, a dynamic risk assessment method is proposed by integrating the system-theoretic accident model and process approach (STAMP) and the cascading failure propagation model (CFPM). Firstly, STAMP is used to model and analyze the system safety of a process system. Two CFPMs are then proposed to measure risk accumulation under two different engineering situations. The proposed method is applied to the Chevron Richmond refinery crude unit and its associated upstream process. The results show that the proposed approach can effectively quantify the process of risk accumulation. This method can generate a real-time dynamic risk profile to support auxiliary decision-making.","Cascading failure propagation model (CFPM); Fault propagation; Risk accumulation; STAMP","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:dd6a5c46-601d-4625-8b90-55ee9ee12330","http://resolver.tudelft.nl/uuid:dd6a5c46-601d-4625-8b90-55ee9ee12330","Enhancing pseudocapacitive intercalation in Ti3C2T x MXene with molecular crowding electrolytes","Chen, C. (TU Delft RST/Storage of Electrochemical Energy); de Kogel, Albert (Student TU Delft); Weijers, M.J. (TU Delft ChemE/Materials for Energy Conversion and Storage); Bannenberg, L.J. (TU Delft RID/TS/Instrumenten groep); Wang, Xuehang (TU Delft RST/Storage of Electrochemical Energy)","","2024","The growing demand for safe, cost-efficient, high-energy and high-power electrochemical energy storage devices has stimulated the development of aqueous-based supercapacitors with high capacitance, high rate capability, and high voltage. 2D titanium carbide MXene-based electrodes have shown excellent rate capability in various dilute aqueous electrolytes, yet their potential window is usually narrower than 1.2 V. In this study, we show that the potential window of Ti3C2T x MXene can be efficiently widened to 1.5 V in a cost-effective and environmentally benign polyethylene glycol (PEG) containing molecular crowding electrolyte. Additionally, a pair of redox peaks at −0.25 V/−0.05 V vs. Ag (cathodic/anodic) emerged in cyclic voltammetry after the addition of PEG, yielding an additional 25% capacitance. Interestingly, we observed the co-insertion of the molecular crowding agent PEG-400 during the Li+ intercalation process based on in-situ x-ray diffraction analysis. As a result, Ti3C2T x electrodes presented an interlayer space change of 4.7 Å during a complete charge/discharge cycle, which is the largest reversible interlayer space change reported so far for MXene-based electrodes. This work demonstrates the potential of adding molecular crowding agents to improve the performance of MXene electrodes in aqueous electrolytes and to enlarge the change of the interlayer spacing.","electrochemical energy storage; intercalation; interlayer spacing; molecular crowding electrolyte; MXene; polyethylene glycol; supercapacitor","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:6c51424d-93f1-445e-ba94-6640116ec968","http://resolver.tudelft.nl/uuid:6c51424d-93f1-445e-ba94-6640116ec968","Topology optimization of differentiable microstructures","Zhai, X. (TU Delft Materials and Manufacturing; University of Science and Technology of China); Wang, Weiming (The University of Manchester); Chen, Falai (University of Science and Technology of China); Wu, J. (TU Delft Materials and Manufacturing)","","2024","Recent years have seen a growing interest in topology optimization of functionally graded microstructures, characterized by an array of microstructures with varying volume fractions. However, microstructures optimized at slightly different volume fractions do not necessarily connect well when placed adjacently. Furthermore, optimization is commonly performed on a finite set of volume fractions, limiting the number of microstructure configurations. In this paper, we introduce the concept of differentiable microstructures, which are parameterized microstructures that exhibit continuous variations in both geometry and mechanical properties. To construct such microstructures, we propose a novel formulation for topology optimization. In this approach, a series of 2-dimensional microstructures is represented using a height field, and the objective is to maximize the bulk modulus of the entire series. Through this optimization process, an initial microstructure with a small volume fraction undergoes non-uniform transformations, generating a series of microstructures with progressively increasing volume fractions. Notably, when compared to traditional uniform morphing methods, our proposed optimization approach yields a series of microstructures with bulk moduli that closely approach the theoretical limit.","Functionally graded microstructures; Inverse homogenization; Topology optimization","en","journal article","","","","","","","","","","","Materials and Manufacturing","","",""
"uuid:65ffe8a9-4bed-47d4-a021-9e1d85f3c564","http://resolver.tudelft.nl/uuid:65ffe8a9-4bed-47d4-a021-9e1d85f3c564","High dielectric filler for all-solid-state lithium metal battery","Wang, C. (TU Delft RST/Storage of Electrochemical Energy; The Hong Kong Polytechnic University); Liu, M. (TU Delft RST/Storage of Electrochemical Energy); Bannenberg, L.J. (TU Delft RID/TS/Instrumenten groep); Zhao, C. (TU Delft RST/Storage of Electrochemical Energy); Thijs, M.A. (TU Delft RID/TS/Technici Pool); Boshuizen, B. (TU Delft ChemE/O&O groep); Ganapathy, S. (TU Delft RID/TS/Instrumenten groep); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2024","Lithium metal with its high theoretical capacity and low negative potential is considered one of the most important candidates to raise the energy density of all-solid-state batteries. However, lithium filament growth and its induced solid electrolyte decomposition pose severe challenges to realize a long cycle life. Here, dendrite growth in solid-state Li metal batteries is alleviated by introducing a high dielectric material, barium titanate, as a filler that removes the electric field gradients that catalyze dendrite formation. In symmetrical Li-metal cells, this results in a very small over-potential of only 48 mV at a relatively high current density of 1 mA cm−2, when cycling a capacity of 2 mA h cm−2 during 1700 h. The high dielectric filler improves the Coulombic efficiency and cycle life of full cells and suppresses electrolyte decomposition as indicated by solid-state nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) measurements. This indicates that the high dielectric filler can suppress dendrite formation, thereby reducing solid electrolyte decomposition reactions, resulting in the observed low overpotentials and improved cycling efficiency.","All-solid-state batteries; Dendrite-free; Electrolyte decomposition; High dielectric filler; Li-metal anode","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:1f92feaf-60a1-4ac3-ad12-9cfc761303eb","http://resolver.tudelft.nl/uuid:1f92feaf-60a1-4ac3-ad12-9cfc761303eb","How aromatic dissolved organic matter differs in competitiveness against organic micropollutant adsorption","Wang, Q. (TU Delft Computational Design and Mechanics; Chinese Academy of Sciences); Lechtenfeld, Oliver J. (Helmholtz Centre for Environmental Research - UFZ); Rietveld, L.C. (TU Delft Sanitary Engineering); Schuster, Jonas (Hamburg University of Technology); Ernst, Mathias (Hamburg University of Technology); Hofman-Caris, Roberta (KWR Water Research Institute; Wageningen University & Research); Kaesler, Jan (Helmholtz Centre for Environmental Research - UFZ); Wang, Chunmiao (Chinese Academy of Sciences); Yang, Min (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Yu, Jianwei (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Zietzschmann, F.E. (TU Delft Sanitary Engineering; Berliner Wasserbetriebe)","","2024","Activated carbon is employed for the adsorption of organic micropollutants (OMPs) from water, typically present in concentrations ranging from ng L−1 to μg L−1. However, the efficacy of OMP removal is considerably deteriorated due to competitive adsorption from background dissolved organic matter (DOM), present at substantially higher concentrations in mg L−1. Interpreting the characteristics of competitive DOM is crucial in predicting OMP adsorption efficiencies across diverse natural waters. Molecular weight (MW), aromaticity, and polarity influence DOM competitiveness. Although the aromaticity-related metrics, such as UV254, of low MW DOM were proposed to correlate with DOM competitiveness, the method suffers from limitations in understanding the interplay of polarity and aromaticity in determining DOM competitiveness. Here, we elucidate the intricate influence of aromaticity and polarity in low MW DOM competition, spanning from a fraction level to a compound level, by employing direct sample injection liquid chromatography coupled with ultrahigh-resolution Fourier-transform ion cyclotron resonance mass spectrometry. Anion exchange resin pre-treatment eliminated 93% of UV254-active DOM, predominantly aromatic and polar DOM, and only minimally alleviated DOM competition. Molecular characterization revealed that nonpolar molecular formulas (constituting 26% PAC-adsorbable DOM) with medium aromaticity contributed more to the DOM competitiveness. Isomer-level analysis indicated that the competitiveness of highly aromatic LMW DOM compounds was strongly counterbalanced by increased polarity. Strong aromaticity-derived π-π interaction cannot facilitate the competitive adsorption of hydrophilic DOM compounds. Our results underscore the constraints of depending solely on aromaticity-based approaches as the exclusive interpretive measure for DOM competitiveness. In a broader context, this study demonstrates an effect-oriented DOM analysis, elucidating counterbalancing interactions of DOM molecular properties from fraction to compound level.","Activated carbon; Dissolved organic matter (DOM); Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS); Multi-component adsorption; Organic micropollutants","en","journal article","","","","","","","","","","","Computational Design and Mechanics","","",""
"uuid:fa3a5bd1-02d6-4ba4-b7dc-3d6782cb6df6","http://resolver.tudelft.nl/uuid:fa3a5bd1-02d6-4ba4-b7dc-3d6782cb6df6","Random organic framework membranes with hierarchical channels for H2 separation","Luan, Liping (Tianjin University); Shi, Puxin (Tianjin University); Wang, Zhi (Tianjin University); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering); Liu, Xinlei (Tianjin University)","","2024","Novel membrane materials for H2 separation are wanted. How to overcome the “trade-off” between membrane permeability and selectivity is a tough challenge. Here we report new random organic framework membranes with benzimidazole and imine linkages to form hierarchical channels. Both high H2-selective and fast H2 transport pathways are created. The preparation parameters are thoroughly studied and the membrane structures are well characterized by SEM, AFM, NMR, XPS, gas sorption, etc. Effect of feed conditions on membrane performance, such as composition, pressure and temperature, is investigated. The membrane performance transcends the upper bounds of H2/CO2, H2/N2 and H2/CH4 with excellent stability.","Benzimidazole and imine linked polymer; H separation; Hierarchical channels; Random organic framework membranes","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-08","","","ChemE/Catalysis Engineering","","",""
"uuid:04d25e38-1ac5-4dd9-b6b3-9cf1f70bbdc8","http://resolver.tudelft.nl/uuid:04d25e38-1ac5-4dd9-b6b3-9cf1f70bbdc8","Multiscale modelling and experimental analysis of ultrasonic-assisted drilling of GLARE fibre metal laminates","Atif, Muhammad (Beijing Institute of Technology); Wang, Xibin (Beijing Institute of Technology); Xie, Lijing (Beijing Institute of Technology); Giasin, Khaled (University of Portsmouth); Ma, Yuan (Tsinghua University); Jiang, Chulin (Teesside University); Koklu, Ugur (Karamanoglu Mehmetbey University); Sinke, J. (TU Delft Group Sinke)","","2024","This study aims to evaluate the effectiveness of Ultrasonic-assisted drilling (UAD) of Glass laminate aluminium reinforced epoxy (GLARE) at high cutting speeds (Spindle speeds: 3000–7500 rpm; feed rates 300–750 mm/min) by analysing the thrust force and hole quality metrics (surface roughness, hole size, and burr formations. The research also presents numerical modelling of FMLs under conventional and UAD regimes to predict thrust force using ABAQUS/SIMULIA. The thrust force and exit burrs were reduced by up to 40.83 % and 80 %, respectively. The surface roughness metrics (Ra and Rz) were slightly higher using UAD but remained within the desirable limits of surface roughness for machined aeronautical structures. The discrepancy between the simulation and experimental results was adequate and did not exceed 15 %. The current study shows that it is feasible to drill holes in GLARE using higher cutting parameters and maintain excellent hole quality, which means increased productivity and reduced costs.","GLARE; Surface roughness; Thrust force; Ultrasonic assisted drilling","en","journal article","","","","","","","","","","","Group Sinke","","",""
"uuid:090488a2-8ca2-4a3d-afab-950d736c43b0","http://resolver.tudelft.nl/uuid:090488a2-8ca2-4a3d-afab-950d736c43b0","Recyclable Conjugated Polyelectrolyte Hydrogels for Pseudocapacitor Fabrication","Jiang, Yan (National University of Singapore); Vázquez, Ricardo Javier (National University of Singapore; Nanyang Technological University; Indiana University - Purdue University); McCuskey, Samantha R. (National University of Singapore; Nanyang Technological University); Yip, Benjamin Rui Peng (National University of Singapore); Quek, Glenn (National University of Singapore); Ohayon, David (National University of Singapore); Kundukad, Binu (Nanyang Technological University); Wang, Xuehang (TU Delft RST/Storage of Electrochemical Energy); Bazan, Guillermo C. (National University of Singapore; Nanyang Technological University; University of California)","","2024","In alignment with widespread interest in carbon neutralization and sustainable practices, we disclose that conjugated polyelectrolyte (CPE) hydrogels are a type of recyclable, electrochemically stable, and environmentally friendly pseudocapacitive material for energy storage applications. By leveraging ionic-electronic coupling in a relatively fluid medium, one finds that hydrogels prepared using a fresh batch of an anionic CPE, namely, Pris-CPE-K, exhibit a specific capacitance of 32.6 ± 6.6 F g-1 in 2 M NaCl and are capable of 80% (26.1 ± 6.5 F g-1) capacitance retention after 100,000 galvanostatic charge-discharge (GCD) cycles at a current density (J) of 10 A g-1. We note that equilibration under a constant potential prior to GCD analysis leads to the K+ counterions in the CPE exchanging with Na+ and, thus, the relevant active material Pris-CPE-Na. It is possible to remove the CPE material from the electrochemical cell via extraction with water and to carry out a simple purification through dialysis to produce a recycled material, namely Re-CPE-Na. The recycling workup has no significant detrimental impact on the electrochemical performance. Specifically, Re-CPE-Na hydrogels display an initial specific capacitance of 26.3 ± 1.2 F g-1 (at 10 A g-1) and retain 77% of the capacitance after a subsequent 100,000 GCD cycles. Characterization by NMR, FTIR, and Raman spectroscopies, together with XPS and GPC measurements, revealed no change in the structure of the backbone or side chains. However, rheological measurements gave evidence of a slight loss in G′ and G′′. Overall, that CPE hydrogels display recyclability argues in favor of considering them as a novel materials platform for energy storage applications within an economically viable circular recycling strategy.","conjugated polyelectrolytes; cycling stability; energy storage; organic mixed ionic-electronic conductors; recyclable pseudocapacitive material","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-27","","","RST/Storage of Electrochemical Energy","","",""
"uuid:28077850-61f9-42b3-8626-5e6861619088","http://resolver.tudelft.nl/uuid:28077850-61f9-42b3-8626-5e6861619088","Diversity-Based Topology Optimization of Soft Robotic Grippers","Pinskier, Josh (The Commonwealth Scientific and Industrial Research Organisation (CSIRO)); Wang, Xing (The Commonwealth Scientific and Industrial Research Organisation (CSIRO)); Liow, Lois (The Commonwealth Scientific and Industrial Research Organisation (CSIRO)); Xie, Yue (University of Cambridge); Kumar, Prabhat (Indian Institute of Technology Hyderabad); Langelaar, Matthijs (TU Delft Computational Design and Mechanics); Howard, David (The Commonwealth Scientific and Industrial Research Organisation (CSIRO))","","2024","Soft grippers are ideal for grasping delicate, deformable objects with complex geometries. Universal soft grippers have proven effective for grasping common objects, however complex objects or environments require bespoke gripper designs. Multi-material printing presents a vast design-space which, when coupled with an expressive computational design algorithm, can produce numerous, novel, high-performance soft grippers. Finding high-performing designs in challenging design spaces requires tools that combine rapid iteration, simulation accuracy, and fine-grained optimization across a range of gripper designs to maximize performance, no current tools meet all these criteria. Herein, a diversity-based soft gripper design framework combining generative design and topology optimization (TO) are presented. Compositional pattern-producing networks (CPPNs) seed a diverse set of initial material distributions for the fine-grained TO. Focusing on vacuum-driven multi-material soft grippers, several grasping modes (e.g. pinching, scooping) emerging without explicit prompting are demonstrated. Extensive automated experimentation with printed multi-material grippers confirms optimized candidates exceed the grasp strength of comparable commercial designs. Grip strength, durability, and robustness is evaluated across 15,170 grasps. The combination of fine-grained generative design, diversity-based design processes, high-fidelity simulation, and automated experimental evaluation represents a new paradigm for bespoke soft gripper design which is generalizable across numerous design domains, tasks, and environments.","computational design; soft robotics; topology optimization","en","journal article","","","","","","","","","","","Computational Design and Mechanics","","",""
"uuid:a4fb1d7a-7ad7-4a7f-a8ad-3a3dd7e20d44","http://resolver.tudelft.nl/uuid:a4fb1d7a-7ad7-4a7f-a8ad-3a3dd7e20d44","Synergetic-informed deep reinforcement learning for sustainable management of transportation networks with large action spaces","Lai, Li (The Hong Kong Polytechnic University); Dong, You (The Hong Kong Polytechnic University); Andriotis, C. (TU Delft Architectural Technology); Wang, Aijun (Wuhan University of Technology); Lei, Xiaoming (The Hong Kong Polytechnic University)","","2024","Effective transportation network management systems should consider safety and sustainability objectives. Existing research on large-scale transportation network management often employs the assumption that bridges can be considered individually under these objectives. However, this simplification misses accurate system-level representations, induced by multiple components, network topology, and global maintenance actions. To address these limitations, this paper presents a deep reinforcement learning (DRL) framework that draws inspiration from biological learning behaviors to determine optimal life-cycle management policies. It incorporates synergetic branches and hierarchical rewards, factorizing the action space and, thereby, diminishing system complexity from exponential to linear with respect to the number of bridges. Extensive experiments based on a realistic case study demonstrate that the proposed method outperforms expert maintenance strategies and state-of-the-art decision-making methods. Overall, the proposed DRL framework can assist engineers by offering adaptive solutions to maintenance planning. It also provides solutions that address large action spaces within complex systems.","deep reinforcement learning; infrastructure management; maintenance optimization; hierarchical reward; life-cycle analysis; large discrete action spaces","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-06","","","Architectural Technology","","",""
"uuid:39016597-6bf1-4636-89c2-96cf9cf1707e","http://resolver.tudelft.nl/uuid:39016597-6bf1-4636-89c2-96cf9cf1707e","An integrated approach to quantitative resilience assessment in process systems","Sun, H. (TU Delft Safety and Security Science; Anhui University of Technology; China University of Petroleum (East China)); Yang, M. (TU Delft Safety and Security Science); Wang, Haiqing (China University of Petroleum (East China))","","2024","Chemical process systems are becoming more automated and complex, which leads to increased interaction and interdependence between the human and technical elements of process systems. This urges the need for updating the safety assessment method by treating “safety” as an emergent property of a system. Uncertainty comes together with complexity. To enhance system ability of dealing with uncertain disruptions, this paper proposes a quantitative resilience assessment method by modeling the failure propagation (initiated by a disruption) across the functional units of a system. The Functional Resonance Analysis Method (FRAM) is utilized to model the system operation to represent the relationship among its function units and to consider the interactions among human-technical factors. Then, a Cascading Failure Propagation Model (CFPM) is developed to quantify the fault propagation process and reflect the system functionality changes over time for resilience assessment. The proposed method is applied to a propane-feeding control system. The results show that it can help practitioners understand the process of fault propagation and risk increase, identify potential ways to design a more resilient system to respond to uncertain disruptions/attacks, and provide a real-time dynamic resilience profile to support decision-making.","Human-technical systems, FRAM, resilience; Process safety","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-13","","","Safety and Security Science","","",""
"uuid:179cab11-2b3a-4d78-b841-7ccb54345d96","http://resolver.tudelft.nl/uuid:179cab11-2b3a-4d78-b841-7ccb54345d96","Transfer learning for improved generalizability in causal physics-informed neural networks for beam simulations","Kapoor, T. (TU Delft Railway Engineering); Wang, H. (TU Delft Railway Engineering); Nunez, Alfredo (TU Delft Railway Engineering); Dollevoet, R.P.B.J. (TU Delft Railway Engineering)","","2024","This paper proposes a novel framework for simulating the dynamics of beams on elastic foundations. Specifically, partial differential equations modeling Euler–Bernoulli and Timoshenko beams on the Winkler foundation are simulated using a causal physics-informed neural network (PINN) coupled with transfer learning. Conventional PINNs encounter challenges in handling large space–time domains, even for problems with closed-form analytical solutions. A causality-respecting PINN loss function is employed to overcome this limitation, effectively capturing the underlying physics. However, it is observed that the causality-respecting PINN lacks generalizability. We propose using solutions to similar problems instead of training from scratch by employing transfer learning while adhering to causality to accelerate convergence and ensure accurate results across diverse scenarios. The primary contribution of this paper lies in introducing a causality-respecting PINN loss function in the context of structural engineering and coupling it with transfer learning to enhance the generalizability of PINNs in simulating the dynamics of beams on elastic foundations. Numerical experiments on the Euler–Bernoulli beam highlight the efficacy of the proposed approach for various initial conditions, including those with noise in the initial data. Furthermore, the potential of the proposed method is demonstrated for the Timoshenko beam in an extended spatial and temporal domain. Several comparisons suggest that the proposed method accurately captures the inherent dynamics, outperforming the state-of-the-art physics-informed methods under standard L2-norm metric and accelerating convergence.","Biharmonic equations; Causality; Elastic foundation; Euler–Bernoulli beam; Physics-informed neural networks (PINNs); Timoshenko beam; Transfer learning","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:4b85c22f-4ed0-4fe1-a137-b064a60b0768","http://resolver.tudelft.nl/uuid:4b85c22f-4ed0-4fe1-a137-b064a60b0768","Adsorption characteristics and mechanisms of water-soluble polymers (PVP and PEG) on kaolin and montmorillonite minerals","Wang, Xintu (Guilin University of Technology; Chinese Academy of Sciences); Xu, Yanghui (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Ou, Q. (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Chen, Wenwen (Guilin University of Technology); van der Meer, W.G.J. (University of Twente; Oasen); Liu, G. (TU Delft Sanitary Engineering; Chinese Academy of Sciences; University of Chinese Academy of Sciences)","","2024","The excessive use and accumulation of water-soluble polymers (WSPs, known as “liquid plastics”) in the environment can pose potential risks to both ecosystems and human health, but the environmental fate of WSPs remains unclear. Here, the adsorption behavior of WSPs with different molecular weight on kaolinite (Kaol) and montmorillonite (Mt) were examined. The results showed that the adsorption of PEG and PVP on minerals were controlled by hydrogen bond and van der Waals force. The Fourier transform infrared (FTIR) spectra and two-dimensional correlation spectroscopy (2D-COS) analysis revealed that there were interactions between the Al-O and Si-O groups of the minerals and the polar O- or N-containing functional groups as well as the alkyl groups of PEG and PVP. The adsorption characteristics of WSPs were closely related to their molecular weight and the pore size of minerals. Due to the relatively large mesopore size of Kaol, both PEG and PVP were absorbed into inner spaces, for which the adsorption capacity increased with molecular weight of the polymers. For Mt, all types of PEG could enter its micropores, while PVP with larger molecular weights appeared to be confined externally, leading to a decrease in the adsorption capacity of PVP with increasing molecular weight. The findings of this study provide a theoretical basis for scientific evaluation of environmental processes of WSPs.","Adsorption; Hydrogen bond; Minerals; Molecular weight; Water-soluble polymers","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:fe4e08a8-628d-422b-9c71-25d5c4366c17","http://resolver.tudelft.nl/uuid:fe4e08a8-628d-422b-9c71-25d5c4366c17","Bichromatic Rabi Control of Semiconductor Qubits","John, V. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft; QuTech); Borsoi, F. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft; QuTech); György, Zoltán (Eötvös University); Wang, C.A. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft; QuTech); Széchenyi, Gábor (Eötvös University); van Riggelen, F. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft; QuTech); Lawrie, W.I.L. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft; QuTech); Hendrickx, N.W. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft; QuTech); Sammak, A. (TU Delft BUS/TNO STAFF; QuTech); Scappucci, G. (TU Delft QCD/Scappucci Lab; Kavli institute of nanoscience Delft; QuTech); Pályi, András (Budapest University of Technology and Economics); Veldhorst, M. (TU Delft QN/Veldhorst Lab; Kavli institute of nanoscience Delft; QuTech)","","2024","Electrically driven spin resonance is a powerful technique for controlling semiconductor spin qubits. However, it faces challenges in qubit addressability and off-resonance driving in larger systems. We demonstrate coherent bichromatic Rabi control of quantum dot hole spin qubits, offering a spatially selective approach for large qubit arrays. By applying simultaneous microwave bursts to different gate electrodes, we observe multichromatic resonance lines and resonance anticrossings that are caused by the ac Stark shift. Our theoretical framework aligns with experimental data, highlighting interdot motion as the dominant mechanism for bichromatic driving.","","en","journal article","","","","","","","","","","","QCD/Veldhorst Lab","","",""
"uuid:2551cd3b-50f1-4ee4-b48a-2966629e4a51","http://resolver.tudelft.nl/uuid:2551cd3b-50f1-4ee4-b48a-2966629e4a51","Clouds dissipate quickly during solar eclipses as the land surface cools","Trees, V.J.H. (TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI)); de Roode, S.R. (TU Delft Atmospheric Remote Sensing); Wiltink, Job I. (Royal Netherlands Meteorological Institute (KNMI); Wageningen University & Research); Meirink, Jan Fokke (Royal Netherlands Meteorological Institute (KNMI)); Wang, P. (TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI)); Stammes, Piet (Royal Netherlands Meteorological Institute (KNMI)); Siebesma, A.P. (TU Delft Atmospheric Remote Sensing)","","2024","Clouds affected by solar eclipses could influence the reflection of sunlight back into space and might change local precipitation patterns. Satellite cloud retrievals have so far not taken into account the lunar shadow, hindering a reliable spaceborne assessment of the eclipse-induced cloud evolution. Here we use satellite cloud measurements during three solar eclipses between 2005 and 2016 that have been corrected for the partial lunar shadow together with large-eddy simulations to analyze the eclipse-induced cloud evolution. Our corrected data reveal that, over cooling land surfaces, shallow cumulus clouds start to disappear at very small solar obscurations (~15%). Our simulations explain that the cloud response was delayed and was initiated at even smaller solar obscurations. We demonstrate that neglecting the disappearance of clouds during a solar eclipse could lead to a considerable overestimation of the eclipse-related reduction of net incoming solar radiation. These findings should spur cloud model simulations of the direct consequences of sunlight-intercepting geoengineering proposals, for which our results serve as a unique benchmark.","","en","journal article","","","","","","","","","","","Atmospheric Remote Sensing","","",""
"uuid:6b4ae14c-fdd7-46a3-93c1-a51f4c981738","http://resolver.tudelft.nl/uuid:6b4ae14c-fdd7-46a3-93c1-a51f4c981738","FedViT: Federated continual learning of vision transformer at edge","Zuo, Xiaojiang (Beijing Institute of Technology); Luopan, Yaxin (Beijing Institute of Technology); Han, Rui (Beijing Institute of Technology); Zhang, Qinglong (Beijing Institute of Technology); Liu, Chi Harold (Beijing Institute of Technology); Wang, Guoren (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Data-Intensive Systems)","","2024","Deep Neural Networks (DNNs) have been ubiquitously adopted in internet of things and are becoming an integral part of our daily life. When tackling the evolving learning tasks in real world, such as classifying different types of objects, DNNs face the challenge to continually retrain themselves according to the tasks on different edge devices. Federated continual learning (FCL) is a promising technique that offers partial solutions but yet to overcome the following difficulties: the significant accuracy loss due to the limited on-device processing, the negative knowledge transfer caused by the limited communication of non-IID (non-Independent and Identically Distributed) data, and the limited scalability on the tasks and edge devices. Moreover, existing FCL techniques are designed for convolutional neural networks (CNNs), which have not utilized the full potential of newly emerged powerful vision transformers (ViTs). Considering ViTs depend heavily on training data diversity and volume, we hypothesize ViTs are well-suited for FCL where data arrives continually. In this paper, we propose FedViT, an accurate and scalable federated continual learning framework for ViT models, via a novel concept of signature task knowledge. FedViT is a client-side solution that continuously extracts and integrates the knowledge of signature tasks which are highly influenced by the current task. Each client of FedViT is composed of a knowledge extractor, a gradient restorer and, most importantly, a gradient integrator. Upon training for a new task, the gradient integrator ensures the prevention of catastrophic forgetting and mitigation of negative knowledge transfer by effectively combining signature tasks identified from the past local tasks and other clients’ current tasks through the global model. We implement FedViT in PyTorch and extensively evaluate it against state-of-the-art techniques using popular federated continual learning benchmarks. Extensive evaluation results on heterogeneous edge devices show that FedViT improves model accuracy by 88.61% without increasing model training time, reduces communication cost by 61.55%, and achieves more improvements under difficult scenarios such as large numbers of tasks or clients, and training different complex ViT models.","Catastrophic forgetting; Continual learning; Edge computing; Federated learning; Knowledge transfer negative; Vision transformer","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-22","","","Data-Intensive Systems","","",""
"uuid:f6a54572-b462-4df9-8a57-5a4645ad5b3c","http://resolver.tudelft.nl/uuid:f6a54572-b462-4df9-8a57-5a4645ad5b3c","Vanadium-Containing Chloroperoxidase-Catalyzed Versatile Valorization of Phenols and Phenolic Acids","Li, Huanhuan (Xi’an Jiaotong University); Duan, Peigao (Xi’an Jiaotong University); Huang, Yawen (Chinese Academy of Sciences); Cui, Chengsen (Chinese Academy of Sciences); Hollmann, F. (TU Delft BT/Biocatalysis); Ma, Yunjian (South China University of Technology); Wang, Yonghua (South China University of Technology); Zhang, Jie (Chinese Academy of Sciences); Liu, Weidong (Chinese Academy of Sciences); Zhang, Wuyuan (Chinese Academy of Sciences)","","2024","The downstream product transformation of lignin depolymerization is of great interest in the production of high-value aromatic chemicals. However, this transformation is often impeded by chemical oxidation under harsh reaction conditions. In this study, we demonstrate that hypohalites generated in situ by the vanadium-containing chloroperoxidase from Curvularia inaequalis (CiVCPO) can halogenate various electron-rich and electron-poor phenol and phenolic acid substrates. Specifically, CiVCPO enabled decarboxylative halogenation, deformylative halogenation, halogenation, and direct oxidation reactions. The versatile transformation routes for the valorization of phenolic compounds showed up to 99% conversion and 99% selectivity, with a turnover number of 60,700 and a turnover frequency of 60 s-1 for CiVCPO. This study potentially expands the biocatalytic toolbox for lignin valorization.","biocatalysis; decarboxylation; halogenation; lignin valorization; vanadium-containing chloroperoxidase","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-18","","","BT/Biocatalysis","","",""
"uuid:2b447c46-3922-4fd3-9ead-d960025e3fce","http://resolver.tudelft.nl/uuid:2b447c46-3922-4fd3-9ead-d960025e3fce","Experimental study on workability and permeability of sandy soils conditioned with thickened foam","Feng, Zhiyao (Central South University China); Wang, Shuying (Central South University China); Qu, Tongming (The Hong Kong University of Science and Technology); Zheng, X. (TU Delft Geo-engineering; Central South University China); Ling, Fanlin (Central South University China)","","2024","Water spewing and muck plugging often occur during earth pressure balance (EPB) shield machines tunnelling in water-rich sandy strata, even though the conventional foam has been employed to condition sandy soils. In this study, a novel thickened foaming agent suitable for EPB shield tunnelling in water-rich sandy strata is developed. In contrast to conventional foam-conditioned sands, the thickened foam-conditioned sand has a low permeability due to the consistent filling of soil pores with the thickened foam, and the initial permeability coefficient decreases by approximately two orders of magnitude. It also exhibits a suitable workability, which is attributed to the enhanced capability of the thickened foam to condition sandy soils. In addition, the effect of concentration on the stability of the foam is explained by the Gibbs-Marangoni effect, and conditioning mechanisms for the thickened foam on sands are discussed from the evolution of foam bubbles.","Earth pressure balance (EPB) shield; Foam-conditioned sand; Permeability; Thickened foam; Workability","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:1748f6c4-08e2-4124-aee3-68398205bfaf","http://resolver.tudelft.nl/uuid:1748f6c4-08e2-4124-aee3-68398205bfaf","Tunable visible emission and persistent luminescence of BaGa2O4:Cu2+","Wang, Lei (Hefei University of Technology); Zhao, Ning (Hefei University of Technology); Zhu, Changrui (Hefei University of Technology); Chen, Lei (Hefei University of Technology); Jiang, Yang (Hefei University of Technology); Zhou, Rulong (Hefei University of Technology); Liu, Yanfang (Hefei University of Technology); Qu, Bingyan (Hefei University of Technology); Hintzen, H.T.J.M. (TU Delft RST/Luminescence Materials)","","2024","In the field of solid-state luminescence, Cu2+ has long been widely acknowledged for its capacity to emit infrared light. However, the occurrence of visible emission from Cu2+ ions had been infrequently observed and reported. In this study, we made an intriguing discovery by examining the behavior of Cu2+ within an irregular coordination environment of Ba in BaGa2O4. When excited by UV light, Cu2+ unexpectedly gave a vibrant yellow–red emission, covering a wavelength range spanning from 500 to 750 nm. More noteworthy, by simply manipulating the excitation wavelength or adjusting the temperature, the peak wavelength of the emission could be effectively tuned from approximately 600 to 660 nm, which could be attributed to the luminescence nature of the charge transfer (CT) between O2− and Cu2+. Moreover, the phosphor material displayed a remarkable persistent luminescence (PerL) lasting up to 12 h after UV light excitation. Through thermoluminescence (TL) measurements and first-principle calculations, we found that the intrinsic defects, such as vacancies of oxygen and gallium (VO and VGa″), played important roles for the PerL phenomena. These findings highlighted the exceptional tunability and PerL properties of BaGa2O4:Cu2+. Our study provided a new potential guideline for the design of Cu2+-activated phosphors in visible region, and opened up new avenues for the research in related functional luminescence materials.","Cu luminescence; Mechanism; Persistent luminescence; Phosphors; Tunable emission","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-01","","","RST/Luminescence Materials","","",""
"uuid:b2ef9acd-9738-431d-a368-a0069ddf756d","http://resolver.tudelft.nl/uuid:b2ef9acd-9738-431d-a368-a0069ddf756d","Sediment fluxes within salt marsh tidal creek systems in the Yangtze Estuary","Sun, J. (TU Delft Coastal Engineering; East China Normal University); van Prooijen, Bram (TU Delft Coastal Engineering); Wang, Xianye (East China Normal University); Zhao, Zhonghao (East China Normal University); He, Qing (East China Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2024","Creeks are essential for salt marshes by conveying water and sediment through this geomorphic system. In this paper, we investigate the mechanisms that determine the residual sediment flux using measurements conducted in tidal creeks in salt marshes of the Yangtze Estuary. A main creek and a secondary creek were studied to explore whether the mechanisms determining residual sediment fluxes through the main creek differ from those in the secondary creek. Measurements in creeks were carried out over 5 years, spanning different months. Sediment import was found during most tides, both in the main creek and the secondary creek, implying that creeks in Chongming generally function as a conveyor belt of sediment into the marsh. However, sediment export can occur during certain overbank tides. When comparing the role of creeks in drainage and sediment delivery, the main creek functions more in delivering sediment while the secondary creek primarily serves as a drainage conduit. To better understand the mechanisms behind sediment fluxes, the residual sediment flux was compared with the residual discharge and the sediment differential (differences in sediment concentration between flood and ebb). Overbank tides generally lead to a net outward discharge as more water from saltmarshes can be concentrated into the marsh creek during ebb tides. This net outward discharge tends to export more sediment during ebb tides. However, due to the sediment abundance during the flood phase in the turbid environment, sediment import can be expected even with the residual export of water. Export of sediment was only found for the few tides with a net outward discharge and a small positive sediment concentration differential. Large negative sediment differentials (larger averaged suspended sediment concentration during ebb tides) have not been observed because the sediment supply during ebb is limited. This paper unravels how the sediment differential and residual discharge contribute to the residual sediment flux, providing a better understanding of sediment dynamics in marsh creek systems.","Marsh creek systems; Sediment availability; Sediment flux","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-04","","","Coastal Engineering","","",""
"uuid:91285ba8-2d88-442a-a3bb-364c0718947b","http://resolver.tudelft.nl/uuid:91285ba8-2d88-442a-a3bb-364c0718947b","Macro-dipoles in soft/hard expanded-polytetrafluoroethylene + fluoroethylenepropylene (ePTFE + FEP) fluoropolymer-film systems for high-output piezoelectric ferroelectret-transducer applications","Wang, Ningzhen (Beijing Forestry University; University of Connecticut); Baferani, Mohamadreza Arab (University of Connecticut); Daniels, Robert (University of Connecticut); Wu, Chao (University of Connecticut); Huo, Jindong (University of Connecticut); van Turnhout, J. (TU Delft Team Erik Offerman); Sotzing, Gregory A. (University of Connecticut); Gerhard, Reimund (University of Potsdam); Cao, Yang (University of Connecticut)","","2024","Multi-layer ferroelectrets consisting of fluoroethylenepropylene (FEP) copolymer and open-porous expanded polytetrafluoroethylene (ePTFE) films exhibit stable internal electret charges, high piezoelectric coefficients and heat resistance, making them promising candidates for wearable sensors or nanogenerators in body-area networks. Here, three- and five-layer (FEP/ePTFE/FEP and FEP/ePTFE/FEP/ePTFE/FEP) ferroelectret stacks were laminated and poled in a corona discharge. The resulting charge distributions were measured by use of the pulsed electro-acoustic (PEA) method and revealed that charges of opposite polarity were trapped at the interfaces between the FEP and ePTFE layers. Thus, the existence of one macro-dipole in the three-layer structure and of two macro-dipoles in the five-layer structure was directly shown for the first time. Moreover, electric-displacement-versus-electric-field (D-E) loops revealed that remnant polarization is given by the number of macro-dipoles in the respective stack. Due to the addition of the macro-dipoles, the piezoelectric d 33 coefficient of the FEP/ePTFE/FEP/ePTFE/FEP stack reaches 200 pC/N even under a potentially non-uniform compression of the soft ePTFE layers. The results should be useful for a better understanding and a performance optimization of ferroelectrets in self-powered intelligent devices.","charge distribution; charge-spring model; ePTFE + FEP ferroelectret; piezoelectricity","en","journal article","","","","","","","","2024-07-11","","","Team Erik Offerman","","",""
"uuid:7ab42167-5443-44e5-9d78-df162057e571","http://resolver.tudelft.nl/uuid:7ab42167-5443-44e5-9d78-df162057e571","Precursor- and waste-free synthesis of spark-ablated nanoparticles with enhanced photocatalytic activity and stability towards airborne organic pollutant degradation","Drdova, Sarka (ETH Zürich; Swiss Federal Laboratories for Materials Science and Technology (Empa)); Gao, Min (ETH Zürich; Swiss Federal Laboratories for Materials Science and Technology (Empa)); Sambalova, Olga (Swiss Federal Laboratories for Materials Science and Technology (Empa)); Pauer, Robin (Swiss Federal Laboratories for Materials Science and Technology (Empa)); Zhou, Zhouping (Student TU Delft); Dimitriadou, Sofia (VSPARTICLE); Schmidt-Ott, A. (TU Delft ChemE/Materials for Energy Conversion and Storage; VSPARTICLE); Wang, J. (ETH Zürich; Swiss Federal Laboratories for Materials Science and Technology (Empa))","","2024","Photocatalyst synthesis typically involves multiple steps, expensive precursors, and solvents. In contrast, spark ablation offers a simple process of electrical discharges in a gap between two electrodes made from a desirable material. This enables a precursor- and waste-free generation of pure metal oxide nanoparticles or mixtures of various compositions. This study presents a two-step method for the production of photocatalytic filters with deposited airborne MnOx, TiO2, and ZnO nanoparticles using spark ablation and calcination processes. The resulting MnOx and TiO2 filters demonstrated almost twice the activity with outstanding performance stability, as compared to sol-gel MnO2 and commercial TiO2. The introduced method is not only simple, precursor- and waste-free, and leads to superior performance for the case studied, but it also has future potential due to its versatility. It can easily produce mixed and doped materials with further improved properties, making it an interesting avenue for future research.","","en","journal article","","","","","","","","","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:e7444ac1-5c3b-4901-a940-986f3962debb","http://resolver.tudelft.nl/uuid:e7444ac1-5c3b-4901-a940-986f3962debb","A study on siting of emergency shelters for dam failure floods considering population distribution and weather effects","Jiao, Yutie (Zhengzhou University); Li, Zongkun (Zhengzhou University); Ge, Wei (Zhengzhou University; Yellow River Engineering Consulting Co); Jing, Laihong (Yellow River Engineering Consulting Co); Wu, Meimei (Henan University of Technology, Zhengzhou); Wang, Te (Zhengzhou University); Sun, Heqiang (Zhengzhou University); Wang, Jianyou (Zhengzhou University); Zhang, Xiangyang (Zhengzhou University); van Gelder, P.H.A.J.M. (TU Delft Safety and Security Science)","","2024","In recent years, dam failures have occurred frequently because of extreme weather, posing a significant threat to downstream residents. The establishment of emergency shelters is crucial for reducing casualties. The selection of suitable shelters depends on key information such as the number and distribution of affected people, and the effective capacity and accessibility of the shelters. However, previous studies on siting shelters did not fully consider population distribution differences at a finer scale. This limitation hinders the accuracy of estimating the number of affected people. In addition, most studies ignored the impact of extreme rainfall on the effective capacity and accessibility of shelters, leading to a low applicability of the shelter selection results. Therefore, in this study, land-use and land-cover change (LUCC) and nighttime lighting data were used to simulate population distribution and determine the number and distribution of affected people. Qualified candidate shelters were obtained based on screening criteria, and their effective capacity and accessibility information under different weather conditions were quantified. Considering factors such as population transfer efficiency, construction cost and shelter capacity constraints, a multi-objective siting model was established and solved using the non-dominated sorting genetic algorithm II (NSGA- II) to obtain the final siting scheme. The method was applied to the Dafangying Reservoir, and the results showed the following: (1) The overall mean relative error (MRE) of the population in the 35 downstream streets was 11.16 %, with good fitting accuracy. The simulation results truly reflect the population distribution. (2) Normal weather screening generated 352 qualified candidate shelters, whereas extreme rainfall weather screening generated 266 candidate shelters. (3) Based on the population distribution and weather factors, four scenarios were set up, with 63, 106, 73, and 131 shelters selected. These two factors have a significant impact on the selection of shelters and the allocation of evacuees, and should be considered in the event of a dam-failure floods.","Dam-failure floods; Emergency transfer; Population distribution; Shelters selection; Weather factors","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-05","","","Safety and Security Science","","",""
"uuid:960886bc-328f-407a-bf2c-faf9c63700df","http://resolver.tudelft.nl/uuid:960886bc-328f-407a-bf2c-faf9c63700df","Hygrothermal effects on fatigue delamination behavior in composite laminates","Yao, Liaojun (Harbin Institute of Technology); Wang, Jiexiong (Harbin Institute of Technology); He, Yonglyu (National University of Defense Technology); Zhao, Xiuhui (National University of Defense Technology); Chen, Xiangming (Aircraft Strength Research Institute); Liu, J. (Harbin Institute of Technology); Guo, Licheng (Harbin Institute of Technology); Alderliesten, R.C. (TU Delft Group Alderliesten)","","2024","Fatigue delamination growth (FDG) is an important failure in composite structures during their long-term operations. Hygrothermal aging can have significant effects on interlaminar resistance. It is therefore really necessary to explore FDG behavior in composite laminates with hygrothermal aging. Dynamic mechanical thermal analysis (DMTA), mode I FDG experiments and fractographic examinations were conducted to fully investigate hygrothermal aging effects and the corresponding mechanisms on FDG behavior. The DMTA results indicated that environmental aging can induce obvious Tg decrease. Mode I experimental fatigue data interpreted via different Paris-type correlations demonstrated that: Bridging has obvious retardation effects on FDG behavior via the Paris interpretations; The modified Paris relation can well characterize the intrinsic FDG behavior around the crack front; The use of the two-parameter Paris-type relation can appropriately account for R-ratio effects, contributing to a master resistance curve in determining mode I FDG behavior. According to these interpretations, it can be concluded that hygrothermal aging can have adverse effects on mode I FDG behavior. SEM examinations demonstrated that moisture absorption can cause fibre/matrix debonding and resin matrix pores/voids in the composite. However, no obvious difference in damage mechanisms was identified in mode I fatigue delamination for composite with/without environmental conditioning. Both fibre/matrix debonding and matrix brittle fracture were identified on fatigue fracture surfaces. Accordingly, it was concluded that fibre/matrix interface and matrix degradation induced by water absorption were the main reasons for a faster mode I fatigue crack growth in environmental aged composite.","Composite laminates; Delamination; Fatigue; Hygrothermal aging","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-30","","","Group Alderliesten","","",""
"uuid:0708f9cb-8de2-43cd-af3c-38bd68ee25f5","http://resolver.tudelft.nl/uuid:0708f9cb-8de2-43cd-af3c-38bd68ee25f5","Synchronized optimization of wind farm start-stop and yaw control based on 3D wake model","Mr. Wang, Q. (TU Delft Wind Energy; Hubei University of Technology); Xu, Tangjie (Hubei University of Technology); von Terzi, D.A. (TU Delft Wind Energy); Xia, Wei (Hubei University of Technology); Wang, Zhenhai (Hubei University of Technology); Zhang, Haoran (Hubei University of Technology)","","2024","In existing wind farms, the overall power output can be increased through yaw control. However, the cooperative control of start/stop, yaw and turbines positions is often overlooked, leading to wake superposition to downstream wind turbines and suboptimal power output. This paper proposes a synchronized optimized method that considers start/stop, yaw and turbines positions control based on a three-dimensional wake model and yaw flow superposition model. The objective function of the proposed strategy is to maximize the power output of the Chapman Ranch (CR) wind farm. Four cases are considered: start-stop, yaw control, start-stop & yaw control and start-stop & yaw & turbines positions control. The particle swarm algorithm is introduced to optimize the wind farm layout. According to the results, considering start-stop, yaw and turbines positions optimization can not only increase the annual power output of the wind farm by 8.85 %, but also avoid the colliding wake in the CR wind farm. However, the other three cases will cause colliding wake in some fields of the CR wind farm. This study provides important guidance on improving the overall power output of existing wind farms.","3D wake model; Optimization; Start-stop; Wind farm layout; yaw control","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-05","","","Wind Energy","","",""
"uuid:c18d2ca0-48c3-4cbb-af67-ae9e6764be68","http://resolver.tudelft.nl/uuid:c18d2ca0-48c3-4cbb-af67-ae9e6764be68","An adaptive agent-based approach for instant delivery order dispatching: Incorporating task buffering and dynamic batching strategies","Lu, Miaojia (Tongji University; Ministry of Education, Shanghai); Yan, Xinyu (The Hong Kong Polytechnic University); Sharif Azadeh, S. (TU Delft Transport and Planning); Wang, P. (TU Delft Transport and Planning; Tongji University)","","2024","The volume of instant delivery has witnessed a significant growth in recent years. Given the involvement of numerous heterogeneous stakeholders, instant delivery operations are inherently characterized by dynamics and uncertainties. This study introduces two order dispatching strategies, namely task buffering and dynamic batching, as potential solutions to address these challenges. The task buffering strategy aims to optimize the assignment timing of orders to couriers, thereby mitigating demand uncertainties. On the other hand, the dynamic batching strategy focuses on alleviating delivery pressure by assigning orders to couriers based on their residual capacity and extra delivery distances. To model the instant delivery problem and evaluate the performances of order dispatching strategies, Adaptive Agent-Based Order Dispatching (ABOD) approach is developed, which combines agent-based modelling, deep reinforcement learning, and the Kuhn-Munkres algorithm. The ABOD effectively captures the system's uncertainties and heterogeneity, facilitating stakeholders learning in novel scenarios and enabling adaptive task buffering and dynamic batching decision-makings. The efficacy of the ABOD approach is verified through both synthetic and real-world case studies. Experimental results demonstrate that implementing the ABOD approach can lead to a significant increase in customer satisfaction, up to 275.42%, while simultaneously reducing the delivery distance by 11.38% compared to baseline policies. Additionally, the ABOD approach exhibits the ability to adaptively adjust buffering times to maintain high levels of customer satisfaction across various demand scenarios. As a result, this approach offers valuable support to logistics providers in making informed decisions regarding order dispatching in instant delivery operations.","Agent-based modelling; Deep reinforcement learning; Dynamic batching; Instant delivery; Task buffering","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:6db4d1fa-a4ec-4374-8154-e226fdbf194d","http://resolver.tudelft.nl/uuid:6db4d1fa-a4ec-4374-8154-e226fdbf194d","Robust additive manufacturable Ni superalloys designed by the integrated optimization of local elemental segregation and cracking susceptibility criteria","Yu, Hao (Northeastern University China); Fu, Jiabo (Northeastern University China); Wang, Chenchong (Northeastern University China); Chen, Yinping (Northeastern University China); Wang, Lingyu (Northeastern University China); Fang, Haixing (European Synchrotron Radiation Facility; Grenoble INP; Université Grenoble Alpes; Université de Lyon); Li, Jinguo (Chinese Academy of Sciences); van der Zwaag, S. (TU Delft Group Garcia Espallargas); Xu, Wei (Northeastern University China)","","2024","To achieve an effective design of additively manufacturable Ni superalloys with decent service performance, a hybrid computational design model has been developed, where the strategy to tailor local elemental segregations was integrated within a scheme of minimizing the cracking susceptibility. More specifically, the phase boundary of primary NbC / γ matrix was introduced into the design routine to tune the spatial distribution of critical solutes at an atomic scale, thereby inhibiting the formation of borides and segregation-induced cracking. Based on the output of the design, new grades of Ni superalloy have been developed with excellent additive manufacturability, as confirmed by the robustness of printing parameters in fabricating low-defect-density samples. The capability of the phase boundaries to evenly distribute boron atoms was validated experimentally, and the cracking induced by uncontrolled boron segregation at grain boundaries was effectively prevented. The newly designed alloys showed good tensile properties and decent oxidation resistance at different service temperatures, which are comparable to those of conventionally produced superalloys. The finding that phase boundaries can be employed to prevent undesirable clustering of boron atoms can be extended to manipulate the distributions of other critical elements, which provides a new path for designing novel Ni superalloys with balanced printability and mechanical properties.","Additive manufacturability; Boron segregation; Computational design; Ni superalloys; Phase boundaries","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-08","","","Group Garcia Espallargas","","",""
"uuid:97cfad13-ee97-4ec2-b8e8-ea029adde6bf","http://resolver.tudelft.nl/uuid:97cfad13-ee97-4ec2-b8e8-ea029adde6bf","Interdependence in rare earth element supply between China and the United States helps stabilize global supply chains","Chen, Wei (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Eckelman, Matthew J. (Northeastern University); Sprecher, B. (TU Delft Design for Sustainability); Chen, Wei (Chinese Academy of Sciences; University of Science and Technology of China); Wang, Peng (Chinese Academy of Sciences; University of Chinese Academy of Sciences)","","2024","Rare earth elements (REEs) are vital to the development of low-carbon technologies. There are rising concerns in the United States and elsewhere about REE supply chain stability and risks given the unvalidated perception in the heavy reliance of China, by far the largest REE supplier. However, the relationship between key countries at different stages of global REE supply chains remains unclear. Here, we use a dynamic flow analysis to explore supply dependence between the United States and China by tracing REE flows from mineral mining to market between 2000 and 2022. Our results indicate complementary and cooperative US–China interactions, especially after 2018 when the United States became a net exporter of REE and China's largest supplier, and China became the largest importer of the US REEs and manufacturer of REE-enabled low-carbon technologies. This intensifying interdependence stabilizes REE supply chains and highlights the importance of cooperative REE trade networks.","critical raw materials; material flow analysis; rare earth elements; sustainable development; US–China cooperation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-05","","","Design for Sustainability","","",""
"uuid:66a1ffe2-9f54-4c7e-b1ab-f203edbd060e","http://resolver.tudelft.nl/uuid:66a1ffe2-9f54-4c7e-b1ab-f203edbd060e","Evaluation of blinds control techniques for daylight and visual comfort in complex real-world conditions","Brembilla, E. (TU Delft Environmental & Climate Design); Wang, Taoning (Lawrence Berkeley National Laboratory); Theodoropoulou, Panagiota (Student TU Delft); Beck, Wouter (Hunter Douglas NL)","","2024","The presence of sensor networks to monitor environmental conditions and the automation of blinds and lighting systems controls is now commonplace in buildings, especially public ones with a high number of occupants. However, implementing control algorithms that are sufficiently reactive to variable sky conditions and that actually meet occupants’ needs is still a challenge. In the present study, we investigate and compare advanced and simple control algorithms developed for a variable occupancy, open space, small sized conference venue. Operation and performance resulting from an optimized approach are assumed to be the benchmark strategy, and two other control algorithms of varying complexity are compared with it. Results show that the optimized control strategy performs best overall, but only marginally compared to the other two strategies. It performed especially well in meeting glare protection requirements, as a glare-related parameter was embedded into its objective function, but it also led to erratic movements of the blind slats’ tilt and it required significantly higher computation times than rule-based control strategies. These two factors make it impossible to implement such strategy as it is in the real building, and indicate that a practical control implementation can be more effective than an optimal one.","daylight; blinds automated control; complex fenestration systems; radiance matrix methods","en","conference paper","IBPSA","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-13","","","Environmental & Climate Design","","",""
"uuid:ddb484e7-190d-4c98-8ede-2ab732c7f299","http://resolver.tudelft.nl/uuid:ddb484e7-190d-4c98-8ede-2ab732c7f299","A multi-step fast charging-based battery capacity estimation framework of real-world electric vehicles","Zhang, D. (TU Delft DC systems, Energy conversion & Storage; Beijing Institute of Technology); Wang, Zhenpo (Beijing Institute of Technology); Liu, Peng (Beijing Institute of Technology); She, Chengqi (Hunan University of Science and Technology); Wang, Qiushi (Beijing Institute of Technology); Zhou, Litao (Beijing Institute of Technology); Qin, Z. (TU Delft DC systems, Energy conversion & Storage)","","2024","Accurately evaluating battery degradation is not only crucial for ensuring the safe and reliable operation of electric vehicles (EVs) but also fundamental for their intelligent management and maximum utilization. However, the non-linearity, non-measurability, and multi-stress coupled operating conditions have posed significant challenges for battery health prediction. This paper proposes a battery capacity estimation framework based on real-world operating data. Firstly, a comprehensive feature pool is constructed from the direct external features extracted during multi-step fast charging processes and the quantitative representation of operating conditions. Subsequently, a two-step feature engineering is introduced to select the most relevant features and eliminate the interference components. The battery capacity estimation framework is then implemented using machine learning methods. Validation results demonstrate that the proposed framework achieves superior estimation accuracy with lower computational expense compared to the modelling process without feature engineering. The MAPE and RMSE reach 1.18% and 1.98 Ah, respectively, representing reductions in errors of up to 8.53% and 11.21%. Collectively, the proposed framework paves the foundation for online health prognostics of batteries under practical operating conditions.","Lithium-ion battery; Capacity estimation; Multi-step fast charging; Machine learning; Real-world data","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-22","","","DC systems, Energy conversion & Storage","","",""
"uuid:474ccbb7-d086-471e-a54b-bc9fa9c91444","http://resolver.tudelft.nl/uuid:474ccbb7-d086-471e-a54b-bc9fa9c91444","Flexible High-Sensitivity Strain Sensor Fabricated with Pdms Micro-Channel Array Using Laser Transmission Pyrolysis Technology","Wang, S. (TU Delft Bio-Electronics); Zong, Qihang (Southern University of Science and Technology); Yang, Huiru (Southern University of Science and Technology); Huang, Qianming (Southern University of Science and Technology); Ye, Huaiyu (Southern University of Science and Technology); French, P.J. (TU Delft Bio-Electronics)","","2024","In recent years, flexible strain sensors based on metal cracks have garnered significant interest for their exceptional sensitivity. However, striking a balance between sensitivity and detection range remains a significant challenge, which often limits its wider application. Herein, we introduce an innovative laser transmission pyrolysis technology to fabricate high-performance flexible strain sensors based on (Au) metal cracks with a microchannel array on the PDMS surface. The fabricated flexible strain sensors exhibit high sensitivity, wide detection range, precise strain resolution, fast response and recovery times, and robust durability. Furthermore, this technology has potential applications in microfluidics, microelectromechanical systems, and optical sensing.","Stretchable strain sensor; Metal film; UV laser; Laser transmission pyrolysis; PDMS pattering","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-22","","","Bio-Electronics","","",""
"uuid:a29c1fb2-05f7-4560-a053-9e02163a7560","http://resolver.tudelft.nl/uuid:a29c1fb2-05f7-4560-a053-9e02163a7560","Release of phosphorus through pretreatment of waste activated sludge differs essentially from that of carbon and nitrogen resources: Comparative analysis across four wastewater treatment facilities","Deng, Shaoyu (Beijing Forestry University); Liu, J. (Beijing Forestry University); Yang, Xiaofan (Beijing Forestry University); Sun, Dezhi (Beijing Forestry University); Wang, Aijie (Harbin Institute of Technology); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology); Cheng, Xiang (Beijing Forestry University)","","2024","The accumulation of phosphorus in activated sludge in wastewater treatment plants (WWTPs) provides potential for phosphorus recovery from sewage. This study delves into the potential for releasing phosphorus from waste activated sludge through two distinct treatment methods—thermal hydrolysis and pH adjustment. The investigation was conducted with activated sludge sourced from four WWTPs, each employing distinct phosphorus removal strategies. The findings underscore the notably superior efficacy of pH adjustment in solubilizing sludge phosphorus compared to the prevailing practice of thermal hydrolysis, widely adopted to enhance sludge digestion. The reversibility of phosphorus release within pH fluctuations spanning 2 to 12 implies that the release of sludge phosphorus can be attributed to the dissolution of phosphate precipitates. Alkaline sludge treatment induced the concurrent liberation of COD, nitrogen, and phosphorus through alkaline hydrolysis of sludge biomass and the dissolution of iron or aluminium phosphates, offering potential gains in resource recovery and energy efficiency.","Activated sludge; Alkaline treatment; Resource recovery; Thermal hydrolysis","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-09","","","BT/Environmental Biotechnology","","",""
"uuid:905164f0-b023-4606-9769-1f598907fa43","http://resolver.tudelft.nl/uuid:905164f0-b023-4606-9769-1f598907fa43","Fast-charge high-voltage layered cathodes for sodium-ion batteries","Wang, Q. (TU Delft RST/Storage of Electrochemical Energy); Zhou, Dong (Helmholtz-Zentrum Berlin); Zhao, C. (TU Delft RST/Storage of Electrochemical Energy); Wang, Jianlin (Chinese Academy of Sciences); Guo, Hao (China Institute of Atomic Energy); Wang, Liguang (Zhejiang University); Yao, Zhenpeng (Shanghai Jiao Tong University); Lu, Jun (Zhejiang University); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2024","Sodium-ion batteries have not only garnered substantial attention for grid-scale energy storage owing to the higher abundance of sodium compared with lithium, but also present the possibility of fast charging because of the inherently higher sodium-ion mobility. However, it remains a phenomenal challenge to achieve a combination of these merits, given the complex structural chemistry of sodium-ion oxide materials. Here we show that O3-type sodium-ion layered cathodes (for example, Na5/6Li2/27Ni8/27Mn11/27Ti6/27O2) have the potential to attain high power density, high energy density (260 Wh kg−1 at the electrode level) and long cycle life (capacity retention of 80% over 700 cycles in full cells). The design involves introduction of characteristic P3-structural motifs into an O3-type framework that serves to promote sodium-ion diffusivity and address detrimental transition metal migration and phase transition at a high state of charge. This study provides a principle for the rational design of sodium-ion layered oxide electrodes and advances the understanding of the composition–structure–property relationships of oxide cathode materials.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-15","","","RST/Storage of Electrochemical Energy","","",""
"uuid:8711ee3f-3ad0-43e2-9f20-7d6c101ef3c0","http://resolver.tudelft.nl/uuid:8711ee3f-3ad0-43e2-9f20-7d6c101ef3c0","Improved Anomaly Detection and Localization Using Whitening-Enhanced Autoencoders","Wang, C. (TU Delft Intelligent Electrical Power Grids); Tindemans, Simon H. (TU Delft Intelligent Electrical Power Grids); Palensky, P. (TU Delft Intelligent Electrical Power Grids)","","2024","Anomaly detection is of considerable significance in engineering applications, such as the monitoring and control of large-scale energy systems. This article investigates the ability to accurately detect and localize the source of anomalies, using an autoencoder neural network-based detector. Correlations between residuals are identified as a source of misclassifications, and whitening transformations that decorrelate input features and/or residuals are analyzed as a potential solution. For two use cases, regarding spatially distributed wind power generation and temporal profiles of electricity consumption, the performance of various data processing combinations was quantified. Whitening of the input data was found to be most beneficial for accurate detection, with a slight benefit for the combined whitening of inputs and residuals. For localization of anomalies, whitening of residuals was preferred, and the best performance was obtained using standardization of the input data and whitening of the residuals using the zero-phase component analysis (ZCA) or zero-phase component analysis-correlation (ZCA-cor) whitening matrix with a small additional offset.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-03","","","Intelligent Electrical Power Grids","","",""
"uuid:1349f6ae-1f9e-49ca-8850-4c50a0ba96d7","http://resolver.tudelft.nl/uuid:1349f6ae-1f9e-49ca-8850-4c50a0ba96d7","Exceptional mechanical performance by spatial printing with continuous fiber: Curved slicing, toolpath generation and physical verification","Fang, G. (TU Delft Emerging Materials; The University of Manchester); Zhang, Tianyu (The University of Manchester); Huang, Yuming (The University of Manchester); Zhang, Zhizhou (The University of Manchester); Masania, K. (TU Delft Group Masania); Wang, C.C. (TU Delft Emerging Materials; The University of Manchester)","","2024","This work explores a spatial printing method to fabricate continuous fiber-reinforced thermoplastic composites (CFRTPCs), which can achieve exceptional mechanical performance. For models giving complex 3D stress distribution under loads, typical planar-layer based fiber placement usually fails to provide sufficient reinforcement due to their orientations being constrained to planes. The effectiveness of fiber reinforcement could be maximized by using multi-axis additive manufacturing (MAAM) to better control the orientation of continuous fibers in 3D-printed composites. Here, we propose a computational approach to generate 3D toolpaths that satisfy two major reinforcement objectives: (1) following the maximal stress directions in critical regions and (2) connecting multiple load-bearing regions by continuous fibers. Principal stress lines are first extracted in an input solid model to identify critical regions. Curved layers aligned with maximal stresses in these critical regions are generated by computing an optimized scalar field and extracting its iso-surfaces. Then, topological analysis and operations are applied to each curved layer to generate a computational domain that preserves fiber continuity between load-bearing regions. Lastly, continuous fiber toolpaths aligned with maximal stresses are generated on each surface layer by computing an optimized scalar field and extracting its iso-curves. A hardware system with dual robotic arms is employed to conduct the physical MAAM tasks depositing polymer or fiber reinforced polymer composite materials by applying a force normal to the extrusion plane to aid consolidation. When comparing to planar-layer based printing results in tension, up to 644% failure load and 240% stiffness are observed on shapes fabricated by our spatial printing method. We demonstrate the versatility of our approach through various complex load cases which demonstrate their successful implementation of continuous fiber printing in 3D.","Continuous fiber reinforced thermoplastic composites; Multi-axis additive manufacturing; Toolpath generation","en","journal article","","","","","","","","","","","Emerging Materials","","",""
"uuid:32e27cc1-23d2-4360-8e35-7fdeb58f315d","http://resolver.tudelft.nl/uuid:32e27cc1-23d2-4360-8e35-7fdeb58f315d","Ultrasmall Gold Nanoparticles Radiolabeled with Iodine-125 as Potential New Radiopharmaceutical","Wang, R. (TU Delft RST/Applied Radiation & Isotopes); Liu, Huanhuan (Zhengzhou University); Antal, Bas (Student TU Delft); Wolterbeek, H.T. (TU Delft Reactor Institute Delft); Denkova, A.G. (TU Delft RST/Applied Radiation & Isotopes)","","2024","The relatively high linear energy transfer of Auger electrons, which can cause clustered DNA damage and hence efficient cell death, makes Auger emitters excellent candidates for attacking metastasized tumors. Moreover, gammas or positrons are usually emitted along with the Auger electrons, providing the possibility of theragnostic applications. Despite the promising properties of Auger electrons, only a few radiopharmaceuticals employing Auger emitters have been developed so far. This is most likely explained by the short ranges of these electrons, requiring the delivery of the Auger emitters to crucial cell parts such as the cell nucleus. In this work, we combined the Auger emitter 125I and ultrasmall gold nanoparticles to prepare a novel radiopharmaceutical. The 125I labeled gold nanoparticles were shown to accumulate at the cell nucleus, leading to a high tumor-killing efficiency in both 2D and 3D tumor cell models. The results from this work indicate that ultrasmall nanoparticles, which passively accumulate at the cell nucleus, have the potential to be applied in targeted radionuclide therapy. Even better tumor-killing efficiency can be expected if tumor-targeting moieties are conjugated to the nanoparticles.","Auger electron; Auger therapy; iodine-125; radionuclide therapy; ultrasmall gold nanoparticle","en","journal article","","","","","","","","","","","RST/Applied Radiation & Isotopes","","",""
"uuid:9fa09968-6b60-41d5-820e-7378758d0d47","http://resolver.tudelft.nl/uuid:9fa09968-6b60-41d5-820e-7378758d0d47","Effects of pore water-rock reaction on heat extraction from the karst geothermal reservoirs: Based on the dual media model","Ji, Jiayan (China University of Petroleum - Beijing); Song, Xianzhi (China University of Petroleum - Beijing); Yi, Junlin (China University of Petroleum - Beijing); Song, G. (TU Delft Applied Geology); Wang, Gaosheng (China University of Petroleum - Beijing)","","2024","Fractures and caves are the main flow and storage channels for the karst geothermal reservoirs, and the water-rock reaction within them significantly affects the thermal performance. Most previous studies concentrated on the fractures, disregarding the impact of the pore water-rock reaction. The objective of this study is to explore the importance of pore water-rock reactions and identify the influence of various parameters when considering pore and fracture water-rock reactions. A 3D thermal-hydraulic-chemical coupling model considering dual media of pores and fractures was developed. The importance of pore water-rock reactions is demonstrated, and quantitatively characterize the effect of injection temperature (Tin), injection rate (Qin), injection concentration (cin), and ratio of the reaction-specific surface area between pore and fracture (Ap/Af) on the thermal performance. Results indicate that the pore water-rock reaction drastically affects the hydraulic conductivity and pressure difference, even leading to an opposite trend. The influence of water-rock reaction in pores on fracture deformation is regulated by Ap/Af, which augments with Ap/Af. The relative contribution of Ap/Af to production temperature, net thermal power, pressure difference, and hydraulic conductivity are 12.8%, 4.1%, 6.8%, and 13.7%, respectively. This study provides a significant guide for accurate production prediction and exploitation of karst-based geothermal reservoirs.","Fracture aperture; Karst-based thermal reserve; Pore structure; Thermal performance; Water-rock reaction","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-08","","","Applied Geology","","",""
"uuid:4ae56e89-0595-4e70-bac0-6bc8f070d169","http://resolver.tudelft.nl/uuid:4ae56e89-0595-4e70-bac0-6bc8f070d169","Vertical dynamic measurements of a railway transition zone: a case study in Sweden","Unsiwilai, S. (TU Delft Railway Engineering); Shen, C. (TU Delft Railway Engineering); Zeng, Y. (TU Delft Railway Engineering); Wang, L. (TU Delft Railway Engineering); Nunez, Alfredo (TU Delft Railway Engineering); Li, Z. (TU Delft Railway Engineering)","","2024","This study presents a measuring framework for railway transition zones using a case study on the Swedish line between Boden and Murjek. The final goal is to better understand the vertical dynamics of transition zones using hammer tests, falling weight measurements, and axle box acceleration (ABA) measurements. Frequency response functions (FRFs) from hammer tests indicate two track resonances, for which the FRF magnitudes on the plain track are at least 30% lower than those at the abutment. The falling weight measurements indicate that the track on the bridge has a much higher deflection than the track on the embankment. Two features from ABA signals, the dominant spatial frequency and the scale average wavelet power, show variation along the transition zone. These variations indicate differences in track conditions per location. Finally, the ABA features in the range of 1.05–2.86 m−1 are found to be related to the track resonance in the range of 30–60 Hz. The findings in this paper provide additional support for physically interpreting train-borne measurements for monitoring transition zones.","Axle box acceleration; Impact excitation; Railway bridge; Railway track vertical dynamic; Railway transition zone","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:83bf377c-cb5d-4a4c-a018-8054c23fca50","http://resolver.tudelft.nl/uuid:83bf377c-cb5d-4a4c-a018-8054c23fca50","System-Wide Effects of Local Bed Disturbance on the Morphological Evolution of a Bifurcating Channel Network","Gao, Weilun (Guangdong University of Technology); Shao, Dongdong (Beijing Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); Zhu, Zhenchang (Guangdong University of Technology; Southern Marine Science and Engineering Guangdong Laboratory); Yang, Zhifeng (Guangdong University of Technology; Southern Marine Science and Engineering Guangdong Laboratory)","","2024","Deltaic channel networks are important conduits for water and material supplies to the fluvial and coastal communities. However, increasing human interventions in river deltas have altered the topology and geometry of channel networks as well as their long-term evolution. While the morphological evolution of a single channel has received extensive studies, the system-wide morphological responses of channel networks to local disturbances remain largely unclear. Here we investigate the morphological responses of a bifurcating channel network subject to local disturbance of channel deepening due to dredging and sand mining through idealized simulations, and further compare the results with the reference scenarios of a single channel and theoretical analysis of the phase plane. The results show that the infilling of the local deepening is associated with the erosion of the entire branch, which also causes system-wide effects on the siltation of the other branch. The morphological responses of the bifurcating channel network consist of a relatively short stage for the infilling of the local deepening followed by a relatively long stage for recovering the equilibrium configuration of the river bifurcation. The system-wide effects of the local disturbance arise from the altered water surface slope and water partitioning downstream of the bifurcation due to the local deepening. Also, the prolonged recovery of the equilibrium configuration is consistent with theoretical analysis, which reveals a slow evolution of the bifurcation when approaching the equilibrium. Our results can help understand the long-term morphological responses of large-scale complex channel networks and inform water managements under increasing human interventions.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-26","","","Coastal Engineering","","",""
"uuid:eefa4cec-3d38-41bd-ab13-13c9cce3fd70","http://resolver.tudelft.nl/uuid:eefa4cec-3d38-41bd-ab13-13c9cce3fd70","Subsidy allocation for residential building energy retrofit: A perspective of families' incomes","You, K. (TU Delft Design & Construction Management; Chongqing University; Beijing Institute of Technology); Qian, QK (TU Delft Design & Construction Management); Cai, Weiguang (Chongqing University); Wang, Xia (Southwestern University of Finance and Economics); Visscher, H.J. (TU Delft Design & Construction Management)","","2024","High household end-user services demand of high-income families results in higher energy consumption compared with low-income families, indicating high-income families may save more energy from similar building energy retrofitting (BER) strategies. Therefore, current BER subsidy policies, which consider technique indicators and ignore families' income, will make high-income families' recovery costs faster, and can't maximize the incentive for residents’ BER awareness. To formulate a equitable and efficient subsidy policies considering families’ income, this study selected Chongqing as the study case and employed propensity scores matching method to evaluate BER's actual energy savings performance for families with different incomes. Meanwhile, the BER subsidies are reallocated based on the dynamic cost payback period. The results indicated that, following BER, the energy savings of high-income families (7.36 kWh/m2) were higher than the mid- (3.96 kWh/m2) and low-income (3.25 kWh/m2) families. Notably, under current subsidy policies, the cost payback period of low-income families is nearly 2.55 and 3.14 times of the mid-income (6.61 years) and high-income (5.37 years) groups, respectively. This study suggests a subsidy of 32.57 yuan/m2, 20.27 yuan/m2, and 15.38 yuan/m2 for low-income, mid-income, and high-income families, respectively. These results provide novel insights into the actual energy-saving performance of residential buildings and help policymakers to formulate fair subsidy policies.","Actual energy savings performance; Building energy efficiency standard; Building energy retrofit; Income; Subsidy allocation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-28","","","Design & Construction Management","","",""
"uuid:5143fd20-6abd-4d34-b60f-5034124dc1e9","http://resolver.tudelft.nl/uuid:5143fd20-6abd-4d34-b60f-5034124dc1e9","The potential of end-of-life ships as a floating seawall and the methodical use of gap resonance for wave attenuation","Wang, G. (TU Delft Ship Hydromechanics and Structures; Technion); Bar, Daniel (Technion); Schreier, S. (TU Delft Ship Hydromechanics and Structures)","","2024","This study examines the potential of a new type of floating seawall, made up of retired large-scale oceangoing vessels, to be used in open water and exposed coastal areas. The main objectives of the research are to assess the effectiveness of the floating seawall concept, to determine the contribution of the gap resonance to wave attenuation, and to compare the results of physical tests with those obtained numerically using ANSYS-AQWA. The use of end-of-life ships in this way provides a unique opportunity to extend their life cycle and reduce the environmental and human health risks associated with the current practice of shipbreaking. The research focuses on a multimodule floating seawall configuration, where each module is composed of two hulls that are rigidly connected side by side, with a small gap to induce gap resonance. The results suggest that end-of-life ships can be used as a resource for the construction of floating seawalls for various marine applications. Furthermore, the results demonstrate the positive influence of the gap resonance on the wave attenuation capacity of the seawall, as well as the limitations of the numerical tool in providing realistic values in this region.","Floating breakwaters; Floating structures; Gap resonance; Hydrodynamic interaction; Ocean and sea space utilization; Wave transmission coefficient","en","journal article","","","","","","","","","","","Ship Hydromechanics and Structures","","",""
"uuid:86377084-00c8-4888-a55d-3c433a016262","http://resolver.tudelft.nl/uuid:86377084-00c8-4888-a55d-3c433a016262","Liquid injectivity in a SAG foam process: Effect of permeability","Gong, J. (TU Delft Reservoir Engineering; Hohai University); Wang, Yuan (Hohai University); Kamarul Bahrim, Ridhwan Zhafri B. (Petronas Research); Tewari, Raj Deo (Petronas Research); Mahamad Amir, Mohammad Iqbal (Petronas Research); Farajzadeh, R. (TU Delft Reservoir Engineering; Shell Global Solutions International B.V.); Rossen, W.R. (TU Delft Reservoir Engineering)","","2024","Foam is utilized in enhanced oil recovery and CO2 sequestration. Surfactant-alternating-gas (SAG) is a preferred approach for placing foam into reservoirs, due to it enhances gas injection and minimizes corrosion in facilities. Our previous studies with similar permeability cores show that during SAG injection, several banks occupy the area near the well where fluid exhibits distinct behaviour. However, underground reservoirs are heterogeneous, often layered. It is crucial to understand the effect of permeability on fluid behaviour and injectivity in a SAG process. In this work, coreflood experiments are conducted in cores with permeabilities ranging from 16 to 2300 mD. We observe the same sequence of banks in cores with different permeabilities. However, the speed at which banks propagate and their overall mobility can vary depending on permeability. At higher permeabilities, the gas-dissolution bank and the forced-imbibition bank progress more rapidly during liquid injection. The total mobilities of both banks decrease with permeability. By utilizing a bank-propagation model, we scale up our experimental findings and compare them to results obtained using the Peaceman equation. Our findings reveal that the liquid injectivity in a SAG foam process is misestimated by conventional simulators based on the Peaceman equation. The lower the formation permeability, the greater the error.","Enhanced oil recovery; Foam; Injectivity; Permeability; Surfactant-alternating-gas","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:a7c6a5cf-825f-4565-a32d-a56b60326e39","http://resolver.tudelft.nl/uuid:a7c6a5cf-825f-4565-a32d-a56b60326e39","Preface","Camara, Oscar (Pompeu Fabra University); Puyol-Antón, Esther (King’s College London); Sermesant, Maxime (Inria); Suinesiaputra, Avan (King’s College London); Tao, Q. (TU Delft ImPhys/Tao group); Wang, Chengyan (Fudan University); Young, Alistair (King’s College London)","","2024","","","en","contribution to periodical","","","","","","","","","","","ImPhys/Tao group","","",""
"uuid:37a7080d-b540-4cfd-bc75-9a1315aa8c60","http://resolver.tudelft.nl/uuid:37a7080d-b540-4cfd-bc75-9a1315aa8c60","Predicting nodal influence via local iterative metrics","Zhang, S. (TU Delft Multimedia Computing); Hanjalic, A. (TU Delft Intelligent Systems); Wang, H. (TU Delft Multimedia Computing)","","2024","Nodal spreading influence is the capability of a node to activate the rest of the network when it is the seed of spreading. Combining nodal properties (centrality metrics) derived from local and global topological information respectively has been shown to better predict nodal influence than using a single metric. In this work, we investigate to what extent local and global topological information around a node contributes to the prediction of nodal influence and whether relatively local information is sufficient for the prediction. We show that by leveraging the iterative process used to derive a classical nodal centrality such as eigenvector centrality, we can define an iterative metric set that progressively incorporates more global information around the node. We propose to predict nodal influence using an iterative metric set that consists of an iterative metric from order 1 to K produced in an iterative process, encoding gradually more global information as K increases. Three iterative metrics are considered, which converge to three classical node centrality metrics, respectively. In various real-world networks and synthetic networks with community structures, we find that the prediction quality of each iterative based model converges to its optimal when the metric of relatively low orders (K∼4) are included and increases only marginally when further increasing K. This fast convergence of prediction quality with K is further explained by analyzing the correlation between the iterative metric and nodal influence, the convergence rate of each iterative process and network properties. The prediction quality of the best performing iterative metric set with K=4 is comparable with the benchmark method that combines seven centrality metrics: their prediction quality ratio is within the range [91%,106%] across all three quality measures and networks. In two spatially embedded networks with an extremely large diameter, however, iterative metric of higher orders, thus a large K, is needed to achieve comparable prediction quality with the benchmark.","OA-Fund TU Delft","en","journal article","","","","","","","","","","Intelligent Systems","Multimedia Computing","","",""
"uuid:a4085c4b-de19-4894-8c45-ea6b684bfe3c","http://resolver.tudelft.nl/uuid:a4085c4b-de19-4894-8c45-ea6b684bfe3c","Centimeter-Level Indoor Visible Light Positioning","Zhu, R. (TU Delft Embedded Systems); Van Den Abeele, Maxim (Katholieke Universiteit Leuven); Beysens, Jona (CSEM SA); Yang, J. (TU Delft Web Information Systems); Wang, Q. (TU Delft Embedded Systems)","","2024","Visible light positioning (VLP) based on the received signal strength (RSS) can leverage a dense deployment of LEDs in future lighting infrastructure to provide accurate and energy-efficient indoor positioning. However, its positioning accuracy heavily depends on the density of collected fingerprints, which is labor-intensive. In this work, we propose a data pre-processing method, including data cleaning and data augmentation, to construct reliable and dense fingerprint samples, thereby alleviating the impact of noisy samples as well as reducing labor intensity. Extensive experiments demonstrate that our proposed method achieves an average positioning error of 1.7 cm, utilizing a sparse dataset that reduces the fingerprint collection effort by 98 percent. Running a tinyML-based model for VLP on the Arduino Nano microcontroller, we also show the possibilities for deploying RSS fingerprint-based VLP systems on resource-constrained embedded devices for real-world applications.","","en","journal article","","","","","","","","2024-09-30","","","Embedded Systems","","",""
"uuid:bc088cea-5a70-459f-8eb9-e5e6d086379b","http://resolver.tudelft.nl/uuid:bc088cea-5a70-459f-8eb9-e5e6d086379b","Towards sustainable groundwater development with effective measures under future climate change in Beijing Plain, China","Liu, S. (TU Delft Water Resources; IHE Delft Institute for Water Education); Zhou, Yangxiao (IHE Delft Institute for Water Education; Hebei University); Eiman, Fatima (IHE Delft Institute for Water Education); McClain, M.E. (TU Delft Water Resources; IHE Delft Institute for Water Education); Wang, Xu sheng (China University of Geosciences)","","2024","To cope with the groundwater depletion problem and achieve sustainable groundwater development, groundwater conservation measures and managed aquifer recharge (MAR) have been implemented worldwide. However, knowledge gaps exit how does the aquifer system respond to these interventions differently and if these interventions are adequate to lead to long-term sustainable groundwater development under future climate change. In Beijing Plain, two measures have been implemented: reduction of groundwater abstraction by substituting groundwater abstraction with transferred surface water and implementation of managed aquifer recharge (MAR) in two major rivers. This study aims to assess how do the shallow and deep aquifers respond to these measures and if these measures can lead to long-term sustainable groundwater development in Beijing Plain under future climate change. A 3-D transient groundwater flow model was calibrated and used to simulate groundwater level and budget changes from 2021 to 2050. The monthly groundwater recharge was estimated using the projected monthly precipitation from three downscaled regional climate models under two scenarios (RCP4.5 and RCP8.5). The results show that declines in groundwater head and storage can be reversed with the combined two measures, thereby contributing to achieve sustainable groundwater development. The reduction of abstractions is a deciding measure to reverse the trend of groundwater depletion, especially in the deep confined aquifers, while large scale MAR schemes can restore the cones of depressions in shallow aquifers and maintain the groundwater abstraction. Climate variation has large impacts on groundwater resources, especially, consecutive dry years can cause rapid groundwater storage depletion. The projected monthly precipitation from 2021 to 2050 is not significantly different from the past. Therefore, the projected future precipitation has minor impacts on groundwater resources in the next 30 years. The findings from the study will support the Beijing municipality to maintain the tight control on groundwater abstraction and to implement large-scale MAR schemes in two rivers. This successful example will encourage managers of other heavily exploited aquifers to take similar measures to achieve sustainable groundwater development.","Beijing Plain; Climate change; Groundwater sustainability; Substitution of abstraction, Managed Aquifer Recharge","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:bc63aa2f-630e-47f2-a093-8042d697bc88","http://resolver.tudelft.nl/uuid:bc63aa2f-630e-47f2-a093-8042d697bc88","Scalable Photochromic Film for Solar Heat and Daylight Management","Meng, Weihao (University of Chinese Academy of Sciences); Kragt, A.J.J. (TU Delft Architectural Technology; ClimAd Technology B.V.); Gao, Yingtao (University of Chinese Academy of Sciences); Brembilla, E. (TU Delft Environmental & Climate Design); van der Burgt, Julia S. (ClimAd Technology B.V.); Schenning, Albertus P.H.J. (Eindhoven University of Technology); Klein, T. (TU Delft Architectural Technology); van den Ham, E.R. (TU Delft Environmental & Climate Design); Wang, Jingxia (University of Chinese Academy of Sciences)","","2024","The adaptive control of sunlight through photochromic smart windows could have a huge impact on the energy efficiency and daylight comfort in buildings. However, the fabrication of inorganic nanoparticle and polymer composite photochromic films with a high contrast ratio and high transparency/low haze remains a challenge. Here, a solution method is presented for the in situ growth of copper-doped tungsten trioxide nanoparticles in polymethyl methacrylate, which allows a low-cost preparation of photochromic films with a high luminous transparency (luminous transmittance Tlum = 91%) and scalability (30 × 350 cm2). High modulation of visible light (ΔTlum = 73%) and solar heat (modulation of solar transmittance ΔTsol = 73%, modulation of solar heat gain coefficient ΔSHGC = 0.5) of the film improves the indoor daylight comfort and energy efficiency. Simulation results show that low-e windows with the photochromic film applied can greatly enhance the energy efficiency and daylight comfort. This photochromic film presents an attractive strategy for achieving more energy-efficient buildings and carbon neutrality to combat global climate change.","daylight comfort; energy saving; photochromicity; scalability; smart windows; transparency; tungsten trioxide","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-05","","","Architectural Technology","","",""
"uuid:e8654a0b-70ad-4eb7-b476-effd3c809477","http://resolver.tudelft.nl/uuid:e8654a0b-70ad-4eb7-b476-effd3c809477","MRHF: Multi-stage Retrieval and Hierarchical Fusion for Textbook Question Answering","Zhu, P. (TU Delft Web Information Systems); Wang, Zhen (Tokyo Institute of Technology); Okumura, Manabu (Tokyo Institute of Technology); Yang, J. (TU Delft Web Information Systems)","Rudinac, Stevan (editor); Worring, Marcel (editor); Liem, Cynthia (editor); Hanjalic, Alan (editor); Jónsson, Björn Pór (editor); Yamakata, Yoko (editor); Liu, Bei (editor)","2024","Textbook question answering is challenging as it aims to automatically answer various questions on textbook lessons with long text and complex diagrams, requiring reasoning across modalities. In this work, we propose MRHF, a novel framework that incorporates dense passage re-ranking and the mixture-of-experts architecture for TQA. MRHF proposes a novel query augmentation method for diagram questions and then adopts multi-stage dense passage re-ranking with large pretrained retrievers for retrieving paragraph-level contexts. Then it employs a unified question solver to process different types of text questions. Considering the rich blobs and relation knowledge contained in diagrams, we propose to perform multimodal feature fusion over the retrieved context and the heterogeneous diagram features. Furthermore, we introduce the mixture-of-experts architecture to solve the diagram questions to learn from both the rich text context and the complex diagrams and mitigate the possible negative effects between features of the two modalities. We test the framework on the CK12-TQA benchmark dataset, and the results show that MRHF outperforms the state-of-the-art results in all types of questions. The ablation and case study also demonstrates the effectiveness of each component of the framework.","Information Retrieval; Mixture-of-Experts; Textbook Question Answering","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-05","","","Web Information Systems","","",""
"uuid:c755c2bd-92d8-499c-94e6-fc01e14aa7d6","http://resolver.tudelft.nl/uuid:c755c2bd-92d8-499c-94e6-fc01e14aa7d6","Influential Node Detection on Graph on Event Sequence","Lu, Zehao (Universiteit Utrecht); Wang, Shihan (Universiteit Utrecht); Ren, Xiao Long (University of Electronic Science and Technology of China); Costas, Rodrigo (Universiteit Leiden); Metze, T.A.P. (TU Delft Organisation & Governance)","Cherifi, Hocine (editor); Rocha, Luis M. (editor); Cherifi, Chantal (editor); Donduran, Murat (editor)","2024","Numerous research efforts have centered on identifying the most influential players in networked social systems. This problem is immensely crucial in the research of complex networks. Most existing techniques either model social dynamics on static networks only and ignore the underlying time-serial nature or model the social interactions as temporal edges without considering the influential relationship between them. In this paper, we propose a novel perspective of modeling social interaction data as the graph on event sequence, as well as the Soft K-Shell algorithm that analyzes not only the network’s local and global structural aspects, but also the underlying spreading dynamics. The extensive experiments validated the efficiency and feasibility of our method in various social networks from real world data. To the best of our knowledge, this work is the first of its kind.","Dynamics of Network; Influential Node Detection; Non-epidemic Spreading","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-21","","","Organisation & Governance","","",""
"uuid:3c4e3e23-f4bc-44fe-b737-ce1e0fcdfed0","http://resolver.tudelft.nl/uuid:3c4e3e23-f4bc-44fe-b737-ce1e0fcdfed0","Towards Cross-Modal Point Cloud Retrieval for Indoor Scenes","Yu, Fuyang (Beihang University); Wang, Zhen (Tokyo Institute of Technology); Li, Dongyuan (Tokyo Institute of Technology); Zhu, P. (TU Delft Web Information Systems); Liang, Xiaohui (Beihang University); Wang, Xiaochuan (Beijing Technology and Business University); Okumura, Manabu (Tokyo Institute of Technology)","Rudinac, Stevan (editor); Worring, Marcel (editor); Liem, Cynthia (editor); Hanjalic, Alan (editor); Jónsson, Björn Pór (editor); Yamakata, Yoko (editor); Liu, Bei (editor)","2024","Cross-modal retrieval, as an important emerging foundational information retrieval task, benefits from recent advances in multimodal technologies. However, current cross-modal retrieval methods mainly focus on the interaction between textual information and 2D images, lacking research on 3D data, especially point clouds at scene level, despite the increasing role point clouds play in daily life. Therefore, in this paper, we proposed a cross-modal point cloud retrieval benchmark that focuses on using text or images to retrieve point clouds of indoor scenes. Given the high cost of obtaining point cloud compared to text and images, we first designed a pipeline to automatically generate a large number of indoor scenes and their corresponding scene graphs. Based on this pipeline, we collected a balanced dataset called CRISP, which contains 10K point cloud scenes along with their corresponding scene images and descriptions. We then used state-of-the-art models to design baseline methods on CRISP. Our experiments demonstrated that point cloud retrieval accuracy is much lower than cross-modal retrieval of 2D images, especially for textual queries. Furthermore, we proposed ModalBlender, a tri-modal framework which can greatly improve the Text-PointCloud retrieval performance. Through extensive experiments, CRISP proved to be a valuable dataset and worth researching. (Dataset can be downloaded at https://github.com/CRISPdataset/CRISP.)","Cross-modal Retrieval; Indoor Scene; Point Cloud","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-29","","","Web Information Systems","","",""
"uuid:552766c2-3cfc-439d-9091-9a88e28e1b9c","http://resolver.tudelft.nl/uuid:552766c2-3cfc-439d-9091-9a88e28e1b9c","Exciton Transport in a Germanium Quantum Dot Ladder","Hsiao, T. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Cova Fariña, P. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Oosterhout, S.D. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; TNO); Jirovec, D. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Zhang, X. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); van Diepen, C.J. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Lawrie, W.I.L. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, C.A. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Sammak, A. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; TNO); Scappucci, G. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Veldhorst, M. (TU Delft QN/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Vandersypen, L.M.K. (TU Delft QuTech Advanced Research Centre; TU Delft QN/Vandersypen Lab; Kavli institute of nanoscience Delft)","","2024","Quantum systems with engineered Hamiltonians can be used to study many-body physics problems to provide insights beyond the capabilities of classical computers. Semiconductor gate-defined quantum dot arrays have emerged as a versatile platform for realizing generalized Fermi-Hubbard physics, one of the richest playgrounds in condensed matter physics. In this work, we employ a germanium 4×2 quantum dot array and show that the naturally occurring long-range Coulomb interaction can lead to exciton formation and transport. We tune the quantum dot ladder into two capacitively coupled channels and exploit Coulomb drag to probe the binding of electrons and holes. Specifically, we shuttle an electron through one leg of the ladder and observe that a hole is dragged along in the second leg under the right conditions. This corresponds to a transition from single-electron transport in one leg to exciton transport along the ladder. Our work paves the way for the study of excitonic states of matter in quantum dot arrays.","","en","journal article","","","","","","","","","","","QCD/Vandersypen Lab","","",""
"uuid:328d3299-e8f0-42d8-9e72-d983e197d95e","http://resolver.tudelft.nl/uuid:328d3299-e8f0-42d8-9e72-d983e197d95e","Sub-seasonal soil moisture anomaly forecasting using combinations of deep learning, based on the reanalysis soil moisture records","Wang, X. (Chongqing Jiaotong University; Hohai University); Corzo, Gerald (IHE Delft Institute for Water Education); Lü, Haishen (Hohai University); Zhou, Shiliang (Chongqing Jiaotong University); Mao, K. (TU Delft Physical and Space Geodesy); Zhu, Yonghua (Hohai University); Duarte Prieto, F.S. (TU Delft Water Resources; IHE Delft Institute for Water Education); Liu, Mingwen (Hohai University); Su, Jianbin (Chinese Academy of Sciences)","","2024","Sub-seasonal drought forecasting is crucial for early warning in estimating agricultural production and optimizing irrigation management, as forecasting skills are relatively weak during this period. Soil moisture exhibits stronger persistence compared to other climate system quantities, which makes it especially influential in shaping land-atmosphere feedback, thus supplying a unique insight into drought forecasting. Relying on the soil moisture memory, this study investigates the combination of multiple deep-learning modules for sub-seasonal drought indices hindcast in the Huai River basin of China, using long-term ERA5-Land soil moisture records with a noise-assisted data analysis tool. The inter-compared deep-learning models include a hybrid model and a committee machine framework. The results show that the performance of the committee machine framework can be improved with the help of series decomposition and the forecasting skill is not impaired with the lead time increases. Overall, this study highlights the potential of combining deep-learning models with soil moisture memory analysis to improve sub-seasonal drought forecasting.","Committee model; Deep learning; Drought forecasting; Noise-assisted tool; Reanalysis soil moisture","en","journal article","","","","","","","","","","","Physical and Space Geodesy","","",""
"uuid:24e4ed3c-9dc2-4405-9b87-ba9d9588f02b","http://resolver.tudelft.nl/uuid:24e4ed3c-9dc2-4405-9b87-ba9d9588f02b","Generalized Model and Deep Reinforcement Learning-Based Evolutionary Method for Multitype Satellite Observation Scheduling","Song, Yanjie (Xidian University); Ou, Junwei (Xiangtan University, Xiangtan); Pedrycz, Witold (University of Alberta; Polish Academy of Sciences; Istinye University); Suganthan, Ponnuthurai Nagaratnam (Qatar University); Wang, X. (TU Delft Learning & Autonomous Control); Xing, Lining (Xidian University); Zhang, Yue (Beihang University)","","2024","Multitype satellite observation, including optical observation satellites, synthetic aperture radar (SAR) satellites, and electromagnetic satellites, has become an important direction in integrated satellite applications due to its ability to cope with various complex situations. In the multitype satellite observation scheduling problem (MTSOSP), the constraints involved in different types of satellites make the problem challenging. This article proposes a mixed-integer programming model and a generalized profit representation method in the model to effectively cope with the situation of multiple types of satellite observations. To obtain a suitable observation plan, a deep reinforcement learning-based genetic algorithm (DRL-GA) is proposed by combining the learning method and genetic algorithm. The DRL-GA adopts a solution generation method to obtain the initial population and assist with local search. In this method, a set of statistical indicators that consider resource utilization and task arrangement performance are regarded as states. By using deep neural networks to estimate the <inline-formula> <tex-math notation=""LaTeX"">$Q$</tex-math> </inline-formula> value of each action, this method can determine the preferred order of task scheduling. An individual update strategy and an elite strategy are used to enhance the search performance of DRL-GA. Simulation results verify that DRL-GA can effectively solve the MTSOSP and outperforms the state-of-the-art algorithms in several aspects. This work reveals the advantages of the proposed generalized model and scheduling method, which exhibit good scalability for various types of observation satellite scheduling problems.","Combinatorial optimization problem; deep reinforcement learning (DRL); Earth Observing System; evolutionary algorithm (EA); generalized model; Genetic algorithms; multitype; Optimization; satellite observation; Satellites; scheduling; Sociology; Statistics; Task analysis","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-15","","","Learning & Autonomous Control","","",""
"uuid:2d975386-a16a-4f4c-bb4e-e93fe38272db","http://resolver.tudelft.nl/uuid:2d975386-a16a-4f4c-bb4e-e93fe38272db","Building Understanding of Experience Design in Digital Health: Preliminary Results Based on Semi-Structured Interviews","Wang, T. (TU Delft Applied Ergonomics and Design); Qian, S. (TU Delft Responsible Marketing and Consumer Behavior); Zhu, Haiou (Loughborough University); Goossens, R.H.M. (TU Delft Human-Centered Design; TU Delft Applied Ergonomics and Design); Giunti, Guido (University of Oulu; Trinity College Dublin); Melles, M. (TU Delft Applied Ergonomics and Design)","Melles, Marijke (editor)","2024","Design is expanding its influence on shaping future healthcare. Ideally, designers apply human-centered design and human factors that introduce theory, principles, and methods to design to optimize people’s healthcare experiences in both digital and non-digital environments. To discuss and implement experience design in healthcare, consensus about experience design in healthcare is needed. Objectives: Therefore, the purpose of this study is to investigate designers’ views on experience design in health, and to uncover their understanding about three experience design concepts, i.e., user experience (UX), patient experience (PEx), and digital patient experience (dPEx). We conducted online semi-structured interviews study with convenience samples who met the eligibility. We used ATLAS.ti for an in-depth data coding following thematic analysis. 24 international designers of digital health solutions, either in industry or in academia took part in the interviews. We found the similarities and differences mentioned between healthcare design and non-healthcare design relate to (1) design principles, (2) user attributes, and (3) design contexts. Furthermore, the differences between UX, PEx, and dPEx can be mapped on five dimensions: people, contexts, purposes, means, and usage scenarios. These insights can help designers and human factors specialists build a common design language for experience design in healthcare. Our study can also assist designers and human factors specialists with experience design in digital health by pointing out the areas where design thinking generally is appropriate and the places where particular expertise in healthcare design is needed.","Digital patient experience; Healthcare design; Human computer interaction; Human-centered design; Patient experience; User experience","en","book chapter","Springer Nature","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-05","","Human-Centered Design","Applied Ergonomics and Design","","",""
"uuid:9420af93-fb9b-4af3-bd0b-61abc74586ec","http://resolver.tudelft.nl/uuid:9420af93-fb9b-4af3-bd0b-61abc74586ec","Size effect on compressive strength of foamed concrete: Experimental and numerical studies","Jiang, Nengdong (Shandong University); Ge, Zhi (Shandong University); Wang, Zhiyuan (Shandong Hi-speed Group); Gao, Tianming (Shandong University); Zhang, Hongzhi (Shandong University); Ling, Yifeng (Shandong University); Šavija, B. (TU Delft Materials and Environment)","","2024","This study investigates the size effect on the compressive strength of foamed concrete at the mesoscale level combining X-ray computed tomography (X-CT) and a discrete lattice model. Image segmentation techniques and X-CT were employed to obtain virtual specimens comprising hydrated cement paste and air voids. The lineal-path function and pore size distribution was used to characterise the air void structure. A two-dimensional lattice fracture model of foamed concrete considering different wet densities was established. The model was verified experimentally at a wet density of 700 kg/m3 and then used to predict the strengths of specimens with wet densities of 600 and 800 kg/m3. Square and rectangular specimens (slenderness ratio = 2) with widths of 10, 20, 40, 70.7, and 100 mm were investigated. Results show that the air void structure significantly influences the observed size effect on the compressive strength in the investigated size range. A random forest regressor was used to predict the compressive strength of the foamed concrete; the regressor yielded satisfactory results. Finally, existing analytical size effect models were used to fit the simulated strength. Although good fitting was achieved, special attention should be given to the applicable range and physical meaning of fitted empirical parameters.","Compressive strength; Foamed concrete; Lattice model; Lineal-path function; Size effect","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:0b452612-dd39-4850-affe-00f25bec66cd","http://resolver.tudelft.nl/uuid:0b452612-dd39-4850-affe-00f25bec66cd","Naturally effective inhibition of microbial corrosion on carbon steel by beneficial biofilm in the South China Sea","Gao, Yu (Northeastern University China); Zhang, Jingru (Northeastern University China); Wang, Donglei (Northeastern University China); Fan, Jiaxin (Northeastern University China); Mol, J.M.C. (TU Delft Team Arjan Mol); Wang, Fuhui (Northeastern University China); Zhang, Danni (Northeastern University China); Xu, Dake (Northeastern University China)","","2024","Microbially influenced corrosion (MIC) of metals exerts a negative effect on the marine environment and causes a great loss of marine facilities. Corrosion prevention in an eco-friendly and sustainable way is a difficult problem to address, especially in the marine environment. In this work, Nocardiopsis dassonville, a corrosive bacteria isolated from the South China Sea was studied by using carbon steel. The results indicate that N. dassonville caused a corrosion loss of 7.68 mg cm−2 and a corrosion pit of 13.0 μm on the carbon steel surface, but the corrosion is inhibited in the presence of Vibrio sp. EF187016 in the medium. Vibrio sp. EF187016 preferentially occupied the carbon steel surface, forming a protective biofilm that hindered the attachment of N. dassonville. In addition, extracellular polymeric substances extracted from Vibrio sp. EF187016 was added to N. dassonvillei inoculated medium and showed a significant inhibition of MIC on carbon steel.","Biofilms; Carbon steel; Corrosion inhibition; Extracellular polymeric substances; Marine environment","en","journal article","","","","","","","","","","","Team Arjan Mol","","",""
"uuid:936ca2c8-2b62-4cf3-a334-7ddab99fbf94","http://resolver.tudelft.nl/uuid:936ca2c8-2b62-4cf3-a334-7ddab99fbf94","Mechanical Framework for Geopolymer Gels Construction: An Optimized LSTM Technique to Predict Compressive Strength of Fly Ash-Based Geopolymer Gels Concrete","Shi, Xuyang (China University of Mining and Technology); Chen, Shuzhao (China University of Mining and Technology); Wang, Qiang (China University of Mining and Technology); Lu, Yijun (Guangzhou University); Ren, S. (TU Delft Pavement Engineering); Huang, Jiandong (Guangzhou University)","","2024","As an environmentally responsible alternative to conventional concrete, geopolymer concrete recycles previously used resources to prepare the cementitious component of the product. The challenging issue with employing geopolymer concrete in the building business is the absence of a standard mix design. According to the chemical composition of its components, this work proposes a thorough system or framework for estimating the compressive strength of fly ash-based geopolymer concrete (FAGC). It could be possible to construct a system for predicting the compressive strength of FAGC using soft computing methods, thereby avoiding the requirement for time-consuming and expensive experimental tests. A complete database of 162 compressive strength datasets was gathered from the research papers that were published between the years 2000 and 2020 and prepared to develop proposed models. To address the relationships between inputs and output variables, long short-term memory networks were deployed. Notably, the proposed model was examined using several soft computing methods. The modeling process incorporated 17 variables that affect the CSFAG, such as percentage of SiO2 (SiO2), percentage of Na2O (Na2O), percentage of CaO (CaO), percentage of Al2O3 (Al2O3), percentage of Fe2O3 (Fe2O3), fly ash (FA), coarse aggregate (CAgg), fine aggregate (FAgg), Sodium Hydroxide solution (SH), Sodium Silicate solution (SS), extra water (EW), superplasticizer (SP), SH concentration, percentage of SiO2 in SS, percentage of Na2O in SS, curing time, curing temperature that the proposed model was examined to several soft computing methods such as multi-layer perception neural network (MLPNN), Bayesian regularized neural network (BRNN), generalized feed-forward neural networks (GFNN), support vector regression (SVR), decision tree (DT), random forest (RF), and LSTM. Three main innovations of this study are using the LSTM model for predicting FAGC, optimizing the LSTM model by a new evolutionary algorithm called the marine predators algorithm (MPA), and considering the six new inputs in the modeling process, such as aggregate to total mass ratio, fine aggregate to total aggregate mass ratio, FASiO2:Al2O3 molar ratio, FA SiO2:Fe2O3 molar ratio, AA Na2O:SiO2 molar ratio, and the sum of SiO2, Al2O3, and Fe2O3 percent in FA. The performance capacity of LSTM-MPA was evaluated with other artificial intelligence models. The results indicate that the R2 and RMSE values for the proposed LSTM-MPA model were as follows: MLPNN (R2 = 0.896, RMSE = 3.745), BRNN (R2 = 0.931, RMSE = 2.785), GFFNN (R2 = 0.926, RMSE = 2.926), SVR-L (R2 = 0.921, RMSE = 3.017), SVR-P (R2 = 0.920, RMSE = 3.291), SVR-S (R2 = 0.934, RMSE = 2.823), SVR-RBF (R2 = 0.916, RMSE = 3.114), DT (R2 = 0.934, RMSE = 2.711), RF (R2 = 0.938, RMSE = 2.892), LSTM (R2 = 0.9725, RMSE = 1.7816), LSTM-MPA (R2 = 0.9940, RMSE = 0.8332), and LSTM-PSO (R2 = 0.9804, RMSE = 1.5221). Therefore, the proposed LSTM-MPA model can be employed as a reliable and accurate model for predicting CSFAG. Noteworthy, the results demonstrated the significance and influence of fly ash and sodium silicate solution chemical compositions on the compressive strength of FAGC. These variables could adequately present variations in the best mix designs discovered in earlier investigations. The suggested approach may also save time and money by accurately estimating the compressive strength of FAGC with low calcium content.","long short-term memory networks; compressive strength; prediction; marine predators algorithm","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:7732ecfc-1cca-4323-aa38-f49247654ac3","http://resolver.tudelft.nl/uuid:7732ecfc-1cca-4323-aa38-f49247654ac3","Fabrication of Living Entangled Network Composites Enabled by Mycelium","Wang, H. (TU Delft Aerospace Manufacturing Technologies; City University of Hong Kong); Tao, Jie (Nanjing University of Aeronautics and Astronautics); Wu, Zhangyu (Southeast University); Weiland, K.M. (TU Delft Group Masania); Wang, Zuankai (The Hong Kong Polytechnic University); Masania, K. (TU Delft Group Masania); Wang, B. (TU Delft Geo-engineering; City University of Hong Kong)","","2024","Organic polymer-based composite materials with favorable mechanical performance and functionalities are keystones to various modern industries; however, the environmental pollution stemming from their processing poses a great challenge. In this study, by finding an autonomous phase separating ability of fungal mycelium, a new material fabrication approach is introduced that leverages such biological metabolism-driven, mycelial growth-induced phase separation to bypass high-energy cost and labor-intensive synthetic methods. The resulting self-regenerative composites, featuring an entangled network structure of mycelium and assembled organic polymers, exhibit remarkable self-healing properties, being capable of reversing complete separation and restoring ≈90% of the original strength. These composites further show exceptional mechanical strength, with a high specific strength of 8.15 MPa g.cm−3, and low water absorption properties (≈33% after 15 days of immersion). This approach spearheads the development of state-of-the-art living composites, which directly utilize bioactive materials to “self-grow” into materials endowed with exceptional mechanical and functional properties.","living composites; mechanical properties; mycelium; phase separation","en","journal article","","","","","","","","","","","Aerospace Manufacturing Technologies","","",""
"uuid:99e01587-21a2-4d19-87ec-366f3d3b9b8d","http://resolver.tudelft.nl/uuid:99e01587-21a2-4d19-87ec-366f3d3b9b8d","Designing lithium halide solid electrolytes","Wang, Q. (TU Delft RST/Storage of Electrochemical Energy); Zhou, Yunan (Tsinghua University); Wang, Xuelong (Brookhaven National Laboratory); Guo, Hao (China Institute of Atomic Energy); Gong, Shuiping (Shanghai Jiao Tong University); Yao, Zhenpeng (Shanghai Jiao Tong University); Ganapathy, S. (TU Delft RST/Storage of Electrochemical Energy; TU Delft RID/TS/Instrumenten groep); Zhao, C. (TU Delft RST/Storage of Electrochemical Energy); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2024","All-solid-state lithium batteries have attracted widespread attention for next-generation energy storage, potentially providing enhanced safety and cycling stability. The performance of such batteries relies on solid electrolyte materials; hence many structures/phases are being investigated with increasing compositional complexity. Among the various solid electrolytes, lithium halides show promising ionic conductivity and cathode compatibility, however, there are no effective guidelines when moving toward complex compositions that go beyond ab-initio modeling. Here, we show that ionic potential, the ratio of charge number and ion radius, can effectively capture the key interactions within halide materials, making it possible to guide the design of the representative crystal structures. This is demonstrated by the preparation of a family of complex layered halides that combine an enhanced conductivity with a favorable isometric morphology, induced by the high configurational entropy. This work provides insights into the characteristics of complex halide phases and presents a methodology for designing solid materials.","","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:e43792be-e3d8-4f44-a780-a1b1c40370af","http://resolver.tudelft.nl/uuid:e43792be-e3d8-4f44-a780-a1b1c40370af","Near-infrared light-driven asymmetric photolytic reduction of ketone using inorganic-enzyme hybrid biocatalyst","Qiao, Li (Hangzhou Normal University); Zhang, Jing (Hangzhou Normal University); Jiang, Yongjian (Hangzhou Normal University); Ma, Bianqin (Hangzhou Normal University); Chen, Haomin (Hangzhou Normal University); Gao, Peng (Hangzhou Normal University); Zhang, Pengfei (Hangzhou Normal University); Wang, Anming (Hangzhou Normal University); Sheldon, R.A. (TU Delft BT/Biocatalysis; University of Witwatersrand)","","2024","Effective photolytic regeneration of the NAD(P)H cofactor in enzymatic reductions is an important and elusive goal in biocatalysis. It can, in principle, be achieved using a near-infrared light (NIR) driven artificial photosynthesis system employing H2O as the sacrificial reductant. To this end we utilized TiO2/reduced graphene quantum dots (r-GQDs), combined with a novel rhodium electron mediator, to continuously supply NADPH in situ for aldo-keto reductase (AKR) mediated asymmetric reductions under NIR irradiation. This upconversion system, in which the Ti-O-C bonds formed between r-GQDs and TiO2 enabled efficient interfacial charge transfer, was able to regenerate NADPH efficiently in 64 % yield in 105 min. Based on this, the pharmaceutical intermediate (R)-1-(3,5-bis(trifluoromethyl)phenyl)ethan-1-ol was obtained, in 84 % yield and 99.98 % ee, by reduction of the corresponding ketone. The photo-enzymatic system is recyclable with a polymeric electron mediator, which maintained 66 % of its original catalytic efficiency and excellent enantioselectivity (99.9 % ee) after 6 cycles.","Aldo-ketone reductase; Cofactor regeneration; Ketone reduction; Photo-enzymatic reduction; TiO/r-GQDs nanocomposite; Upconversion","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-04","","","BT/Biocatalysis","","",""
"uuid:95828fcd-3ab5-4d1b-85b5-a5e209d9ca4f","http://resolver.tudelft.nl/uuid:95828fcd-3ab5-4d1b-85b5-a5e209d9ca4f","Failure probability estimation of natural gas pipelines due to hydrogen embrittlement using an improved fuzzy fault tree approach","Qin, Guojin (Southwest Petroleum University; Shanghai Jiao Tong University); Li, Ruiling (Southwest Petroleum University); Yang, M. (TU Delft Safety and Security Science; Universiti Teknologi Malaysia; University of Tasmania); Wang, Bohong (Zhejiang Ocean University); Ni, Pingan (Xi'an University of Architecture and Technology); Wang, Yihuan (Southwest Petroleum University; Shanghai Jiao Tong University)","","2024","The estimation of failure probability is challenging in hydrogen embrittlement in steel pipelines due to the complexity of the synergistic effect of multiple factors. The present study proposed a hybrid methodology to estimate the failure probability of steel pipelines due to hydrogen embrittlement. The methodology integrates the fault tree analysis with a fuzzy comprehensive evaluation. Fault tree analysis captures the logical relationships between influencing indicators to develop a new assessment model of hydrogen embrittlement in steel pipelines. An improved fuzzy fault tree analysis method was proposed to process aleatoric and epistemic uncertainties to estimate the probability of each basic event due to the difficulty in obtaining the actual probabilities. The failure probability of blended hydrogen natural gas pipelines was estimated by considering the correlation of events. A case study demonstrated the applicability of the proposed method. Maintenance measures can be implemented according to the evaluation results to ensure pipeline safety.","Blended hydrogen natural gas pipelines; Failure probability estimation; Fuzzy fault tree analysis; Hydrogen blistering; Hydrogen embrittlement; Hydrogen-induced cracking","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-05","","","Safety and Security Science","","",""
"uuid:f74ff729-ee27-4f82-9b13-df259df17cb3","http://resolver.tudelft.nl/uuid:f74ff729-ee27-4f82-9b13-df259df17cb3","Condition assessment of underground corroded pipelines subject to hydrogen damage and combined internal pressure and axial compression","Qin, Guojin (Southwest Petroleum University; Shanghai Jiao Tong University); Zhang, Zhenwei (Southwest Petroleum University); Hou, Xiangqin (Southwest Petroleum University); Lu, Hongfang (Southeast University); Huang, Y. (TU Delft Safety and Security Science); Wang, Yihuan (Southwest Petroleum University; Shanghai Jiao Tong University)","","2023","In this work, a 3D finite element (FE) based model was developed to assess the condition of an underground hydrogen transmission pipeline containing a corrosion defect under combined internal pressure and soil movement-induced axial compression. The use of mechanical properties of X100 pipeline steel under different hydrogen charging time models the degree of hydrogen damage in pipelines. Parameter effects, i.e., axial compressive stress, hydrogen damage, defect geometries, and pipeline diameter-to-thickness ratio, were determined. The results demonstrated that the synergistic effect of axial compression, internal pressure, corrosion, and hydrogen damage can lead to a significant decrease in the failure pressure of pipelines. The failure pressure decreased with the wall thickness reduction and increased hydrogen damage, axial compressive stress, defect length, defect depth, and pipe diameter. The competitive effect was observed between the degree of metal loss and hydrogen damage in determining the burst capacity of pipelines. In situations where the pipeline integrity was severely compromised, the failure pressure exhibited minimal reduction despite the increasing severity of hydrogen damage. The stress distribution at the defect zone was influenced by axial compressive stress but remained unaffected by hydrogen damage under normal operating conditions (i.e., an internal pressure of 10 MPa). This work is expected to help operators understand the applicability of elder and in-service pipelines for hydrogen transmission.","Condition assessment; Corrosion; Finite element modeling; Hydrogen damage; Underground pipelines","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-03-09","","","Safety and Security Science","","",""
"uuid:e697880e-2e71-4c37-a45d-996d4377a2ef","http://resolver.tudelft.nl/uuid:e697880e-2e71-4c37-a45d-996d4377a2ef","High-Entropy Liquid Electrolytes for Lithium Batteries","Wang, Q. (TU Delft RST/Storage of Electrochemical Energy)","Wagemaker, M. (promotor); Ganapathy, S. (copromotor); Delft University of Technology (degree granting institution)","2023","","Lithium battery; High-entropy electrolyte; Solvation structure; Interphase","en","doctoral thesis","","978-94-93330-25-2","","","","","","2025-12-01","","","RST/Storage of Electrochemical Energy","","",""
"uuid:ec5051f5-0724-4921-8cbd-3c08b47328a6","http://resolver.tudelft.nl/uuid:ec5051f5-0724-4921-8cbd-3c08b47328a6","Using spins in diamond for quantum technologies","Wang, Y. (TU Delft QCD/Terhal Group)","Terhal, B.M. (promotor); Taminiau, T.H. (promotor); Delft University of Technology (degree granting institution)","2023","Solid-state defect centers, such as the nitrogen-vacancy centers in diamond, represent a promising and versatile platform for quantum technologies. This thesis focuses on overcoming the challenge of noise in diamond to facilitate its practical use in various quantum technology applications.","Defect center; quantum error correction; fault tolerance; quantum error mitigation","en","doctoral thesis","","","","","","","","","","","QCD/Terhal Group","","",""
"uuid:b86bec0b-0f27-4fac-90ae-7ad4bcac407a","http://resolver.tudelft.nl/uuid:b86bec0b-0f27-4fac-90ae-7ad4bcac407a","Quantum Dots Coupled to Superconductors","Wang, Guanzhong (TU Delft QRD/Kouwenhoven Lab)","Kouwenhoven, Leo P. (promotor); Goswami, S. (copromotor); Delft University of Technology (degree granting institution)","2023","The search for Majoranas bound states has witnessed heated efforts in the past decade. This field of research lies at the intersection of both scientific and commercial interests. The Majorana quasiparticle, being its own antiparticle and exhibiting non-abelian exchange statistics, is a unique member of the family of condensed-matter quasiparticles, distinct from most fermions or bosons. These properties are predicted to be instrumental in the building of a new type of qubits, having no energy splitting between qubit states and intrinsically protected from decoherence. In addition, the theory describing Majorana modes has a rich connection to the mathematical language of topology, making its study also of theoretical value. Thus, the prediction of the existence of Majorana zero modes in hybrid semiconducting-superconducting nanowires has been a strong driving force behind the recent technological progress in the making of these materials and devices.
In this thesis, the most recent advance in materials, specifically the making of clean interfaces between semiconductors and superconductors, are applied to the study of the physical properties of superconducting-proximitized electronic states in semiconductors. This technology is combined with quantum dot techniques to investigate electron transport between individual quantum states in proximitized nanowires. The findings include better understanding of electron transport in these systems as well as presenting new potential applications to the field of Majoranas and beyond.
Following the introductory chapters, this thesis first demonstrates a high-efficiency Cooper-pair splitter, enabled by quantum dots with narrow linewidth and a superconductor with a hard gap. The techniques behind the improved efficiency can be used to make a generator of entangled pairs of electrons. We also demonstrate the use of quantum dots as spin detectors capable of revealing the spin structure of individual Cooper pairs. Next, we report the effect of a Cooper-pair splitter's peculiar response to the tuning of electrical gates in both experiment and theory. This includes the discovery of a new interference effect in electron co-tunneling processes through a superconductor. The key to observing this response is to ensure the hybrid nanowire is also a discrete quantum state instead of a superconducting bulk. The discovery above forms the foundation of fine-tuning the types of electron couplings between two quantum dots coupled via a superconductor. The power of this tunability can been seen via the successful making of a minimal artificial Kitaev chain, opening up new possibilities in the search for Majorana zero modes. This approach is less prone to difficulties encountered in other platforms such as material disorder and the interpretability of data.
Moving from studying quantum dots under the influence of a superconducting hybrid, later chapters of this thesis focus on investigating electron properties in the hybrid nanowire using quantum dots as spin-, charge- and energy-selective probes.
We first use them to detect and quantify the spin polarization of Andreev bound states in the hybrid nanowire. Using quantum dots as charge and energy detectors instead, we observe how electrons traverse through the bulk of a hybrid nanowire and reveal a thermoelectric conversion process in the conductance measurements of these devices. Finally, we report on the selective-area growth of InSb, the semiconductor used throughout this thesis, that can form the basis of future developments.","","en","doctoral thesis","","978-90-8593-554-4","","","","","","","","","QRD/Kouwenhoven Lab","","",""
"uuid:12708aca-dff2-4d59-aa0e-af5c275aa728","http://resolver.tudelft.nl/uuid:12708aca-dff2-4d59-aa0e-af5c275aa728","Anomaly Detection and Synthetic Data Generation for Power Systems Using Autoencoder Neural Networks","Wang, C. (TU Delft Intelligent Electrical Power Grids)","Palensky, P. (promotor); Tindemans, Simon H. (copromotor); Delft University of Technology (degree granting institution)","2023","The scale of the power system has been significantly expanded in recent decades. To gain real-time insights into the power system, an increasing number of sensors have been deployed tomonitor grid states, resulting in a rapidly growing number of measurement points. Simultaneously, there has also been a rise in the penetration of renewable energy generation, with energy production that is highly variable and exhibits strong interdependence between different production locations. Such interdependence also applies to electricity demand at various network positions. Furthermore, new demandside response strategies and policies enhance the flexibility of the power system, leading to changes in load profiles. These developments, combined with the structure of the network itself, mean that measurements in the power system generally exhibit strong dependencies. This dependency means that if you know one or more values, you can infer information about others. This applies to time series with measurements that follow each other chronologically as well as to snapshots that show different states of the system at a particular moment in time. A large collection of such time series and snapshots can be represented as a probability distribution in a multidimensional data space. While larger numbers of measurements enable smarter grid operations, high-dimensional stochastic variables with complex univariate and multivariate distributions could also complicate tasks in modeling power system data.....","Anomaly Detection; Synthetic Data Generation; Autoencoder; Power System Operation and Planning; Machine Learning","en","doctoral thesis","","978-90-833109-4-7","","","","","","","","","Intelligent Electrical Power Grids","","",""
"uuid:16e5e2f5-e491-4f86-8a47-6ee0c9ffd000","http://resolver.tudelft.nl/uuid:16e5e2f5-e491-4f86-8a47-6ee0c9ffd000","Development of highly scattering distributed fibre optic sensing for structural health monitoring","Wang, X. (TU Delft Structural Integrity & Composites)","Groves, R.M. (promotor); Benedictus, R. (promotor); Delft University of Technology (degree granting institution)","2023","In this thesis, fibre optic sensing has been investigated as an important technique for structural health monitoring. Distributed fibre optic sensing based on Rayleigh scattering is a fibre optic sensing technique to achieve the spatially continuous strain monitoring for critical locations for the structures. However, the Rayleigh backscattering intensity in commercial optical fibres is low which is a limitation to Rayleigh scattering based fibre optic sensing. In recent years, methods to improve the intensity of the backscattered light in optical fibres have been proposed. By doping nanoparticles into the optical fibre, the backscattered light increases dramatically. Then, the signal-to-noise ratio may increase which would be beneficial for strain measurement with this Rayleigh scattering based method for structural health monitoring. The main research question is ’how can the enhancement of light scattering used in distributed fibre optic sensing be an advantage for structural health monitoring’. The aim of this research is to develop the enhancement of light scattering in the distributed fibre optic sensing as an advantage for structural health monitoring. Gold spherical nanoparticles were chosen as the contrast agents for backscattered light enhancement. The spectral characteristics (light intensity, spectral shift, etc.) have been investigated in detail in this thesis. In this dissertation, firstly, a model of light scattering by gold nanoparticles at optical fibre interfaces was proposed to overcome the difficulty of manufacturing nanoparticle doped optical fibre in an optical laboratory. Gold nanoparticle liquids were dropped to the optical fibre interfaces to evaluate the backscattered light levels from the nanoparticles. Secondly, a model of light scattering by gold nanoparticles in the core of the optical fibres was proposed and an optimisation of light scattering enhancement by gold nanoparticles in fused silica optical fibres was investigated. By comparing the models of light scattering by gold nanoparticles in the core of the optical fibres and at optical fibre interfaces, the relationship between them has been built to evaluate the light scattering level in the optical fibre from the results obtained from the optical fibre interfaces. Then, the characteristics of the backscattered light spectra from the nanoparticle doped optical fibres and the characteristics of the spectral shift under axial strain were investigated. The backscattered light spectral shifts have been compared with the cases of commercial optical fibres and fibre Bragg gratings. A case study of strain acquisition of gold nanoparticle doped distributed optical fibre sensing based on backscattering was investigated with different typical gauge lengths and spectral ranges. Different noise levels were applied to the spectra to analyse the influence on the strain acquisition with signal-to-noise ratio improvement. Lastly, due to the use of gold as the material for nanoparticles, plasmon resonance is induced by gold nanoparticles. The plasmon resonance based gold nanoparticle doped optical fibre strain sensing was studied to make it a potential auxiliary strain detection method along with distributed fibre optic sensing based on Rayleigh scattering.","optical fibre sensor; structural health monitoring; strain sensing; nanoparticle; light scattering","en","doctoral thesis","","978-94-6366-663-3","","","","","","2024-03-13","","","Structural Integrity & Composites","","",""
"uuid:ff5850b9-3621-430c-a396-140f8112ad4d","http://resolver.tudelft.nl/uuid:ff5850b9-3621-430c-a396-140f8112ad4d","Modeling Urban Automated Mobility on-Demand Systems: an Agent-Based Approach","Wang, S. (TU Delft Mathematical Physics)","Lin, H.X. (promotor); Correia, Gonçalo (promotor); Delft University of Technology (degree granting institution)","2023","Automated Mobility-on-Demand (AMoD) systems are expected to revolutionize urban mobility systems. However, there are uncertainties in the planning and operations of AMoD systems. We deem the agent-based approach as being well suited for modeling new phenomena in future AMoD systems and therefore shed some light on the uncertainties about the operation and the impacts of such systems. Recommendations to various stakeholders are provided through the different contributions.","","en","doctoral thesis","","978-90-5584-322-0","","","","","","2024-01-01","","","Mathematical Physics","","",""
"uuid:704dd3e3-ee8b-4104-85a9-8a5321c82f51","http://resolver.tudelft.nl/uuid:704dd3e3-ee8b-4104-85a9-8a5321c82f51","A Fixed-Wing UAV Formation Algorithm Based on Vector Field Guidance","Wang, X. (TU Delft Team Bart De Schutter); Baldi, S. (TU Delft Team Bart De Schutter; Southeast University); Feng, Xuewei (Taiyuan University of Technology); Wu, Changwei (Taiyuan University of Technology); Xie, Hongwei (Taiyuan University of Technology); De Schutter, B.H.K. (TU Delft Team Bart De Schutter)","","2023","The vector field method was originally proposed to guide a single fixed-wing Unmanned Aerial Vehicle (UAV) towards a desired path. In this work, a non-uniform vector field method is proposed that changes in both magnitude and direction, for the purpose of achieving formations of UAVs. As compared to related work in the literature, the proposed formation control law does not need to assume absence of wind. That is, due to the effect of the wind on the UAV, one can handle the UAV air speed being different from its ground speed, and the UAV heading angle being different from its course angle. Stability of the proposed formation method is analyzed via Lyapunov stability theory, and validations are carried out in software-in-the-loop and hardware-in-the-loop comparative experiments. Note to Practitioners - The software-in-the-loop and hardware-in-the-loop experiments, which are done with PX4 autopilot software and hardware, show that the proposed method can be implemented on board of UAVs and integrated with the control architecture of existing autopilot suites. Comparisons with standard formation algorithms show that the proposed method is effective in achieving formation in different path scenarios.","Autonomous aerial vehicles; Autopilot; Computer architecture; Formation control; hardware-in-the-loop; Orbits; PX4 autopilot.; Standards; Task analysis; unmanned aerial vehicles; vector field; Wind speed","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Team Bart De Schutter","","",""
"uuid:14b1af75-bf0f-42d6-b2cb-33232afacd4b","http://resolver.tudelft.nl/uuid:14b1af75-bf0f-42d6-b2cb-33232afacd4b","Distributed Actor-Critic Algorithms for Multiagent Reinforcement Learning Over Directed Graphs","Dai, Pengcheng (Southeast University); Yu, Wenwu (Southeast University); Wang, He (Southeast University); Baldi, S. (TU Delft Team Bart De Schutter; Southeast University)","","2023","Actor-critic (AC) cooperative multiagent reinforcement learning (MARL) over directed graphs is studied in this article. The goal of the agents in MARL is to maximize the globally averaged return in a distributed way, i.e., each agent can only exchange information with its neighboring agents. AC methods proposed in the literature require the communication graphs to be undirected and the weight matrices to be doubly stochastic (more precisely, the weight matrices are row stochastic and their expectation are column stochastic). Differently from these methods, we propose a distributed AC algorithm for MARL over directed graph with fixed topology that only requires the weight matrix to be row stochastic. Then, we also study the MARL over directed graphs (possibly not connected) with changing topologies, proposing a different distributed AC algorithm based on the push-sum protocol that only requires the weight matrices to be column stochastic. Convergence of the proposed algorithms is proven for linear function approximation of the action value function. Simulations are presented to demonstrate the effectiveness of the proposed algorithms.","Approximation algorithms; Convergence; Directed graph; Directed graphs; distributed actor-critic (AC) algorithm; Function approximation; multiagent reinforcement learning (MARL); Protocols; push-sum protocol.; Q-learning; Topology","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-07-11","","","Team Bart De Schutter","","",""
"uuid:e30a43ca-720d-44c7-b385-390da0b2fd6f","http://resolver.tudelft.nl/uuid:e30a43ca-720d-44c7-b385-390da0b2fd6f","Fuzzy Adaptive Zero-Error-Constrained Tracking Control for HFVs in the Presence of Multiple Unknown Control Directions","Lv, Maolong (Air Force Engineering University China); De Schutter, B.H.K. (TU Delft Team Bart De Schutter); Wang, Ying (Air Force Engineering University China); Shen, Di (Air Force Engineering University China)","","2023","This article attempts to realize zero-error constrained tracking for hypersonic flight vehicles (HFVs) subject to unknown control directions and asymmetric flight state constraints. The main challenges of reaching such goals consist in that addressing multiple unknown control directions requires novel conditional inequalities encompassing the summation of multiple Nussbaum integral terms, and in that the summation of conditional inequality may be bounded even when each term approaches infinity individually, but with opposite signs. To handle this challenge, novel Nussbaum functions that are designed in such a way that their signs keep the same on some periods of time are incorporated into the control design, which not only ensures the boundedness of multiple Nussbaum integral terms but preserves that velocity and altitude tracking errors eventually converge to zero. Fuzzy-logic systems (FLSs) are exploited to approximate model uncertainties. Asymmetric integral barrier Lyapunov functions (IBLFs) are adopted to handle the fact that the operating regions of flight state variables are asymmetric in practice, while ensuring the validity of fuzzy-logic approximators. Comparative simulations validate the effectiveness of our proposed methodology in guaranteeing convergence, smoothness, constraints satisfaction, and in handling unknown control directions.","Aerodynamics; Control design; Flight state constraints; hypersonic flight vehicles; Integral equations; Lyapunov methods; Mathematical models; Stability analysis; unknown control directions; Vehicle dynamics; zero-error tracking","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-09-23","","","Team Bart De Schutter","","",""
"uuid:ac0ab01e-8d77-40e0-a304-b5497baf29ba","http://resolver.tudelft.nl/uuid:ac0ab01e-8d77-40e0-a304-b5497baf29ba","Power Disequilibrium Suppression in Bipolar DC Distribution Grids By Using A Series-Parallel Power Flow Controller","Liao, Jianquan (Sichuan University); Zhou, Niancheng (Chongqing University); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Wang, Qianggang (Chongqing University); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2023","The unbalanced power between positive and negative poles in a bipolar DC distribution network (DC-DN) generates an unbalanced current at the neutral line, which enlarges the power losses of the system and the voltage deviation of DC loads. An unbalanced power suppression strategy based on a series-parallel power flow controller (SP-PFC) is proposed in this paper. The SP-PFC is adopted as the interconnection between two different DC-DNs. The topology and operating modes of SP-PFC are analyzed. Subsequently, SP-PFC output voltage and line current expressions under constant power control are derived. The nonlinear relationship between the output voltage and line current is linearized at the operating point. On this basis, the influences of unbalanced load and receiving-end voltage on the SP-PFC are investigated. A small-signal model of bipolar DC-DN containing an SP-PFC is established, and the system stability is analyzed. A simulation model of the bipolar DC distribution network containing an SP-PFC is built up in MATLAB/Simulink, and the effectiveness of the SP-PFC in the suppression of unbalanced power is verified.","Bipolar DC distribution network; unbalanced power; power flow controller; constant power control","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-01","","","DC systems, Energy conversion & Storage","","",""
"uuid:1280a3c4-b32b-4019-9903-c82996848040","http://resolver.tudelft.nl/uuid:1280a3c4-b32b-4019-9903-c82996848040","DeepPick: A Deep Learning Approach to Unveil Outstanding Users Ranking with Public Attainable Features","Li, Wanda (Fudan University); Xu, Zhiwei (Fudan University); Sun, Yi (Fudan University); Gong, Qingyuan (Fudan University); Chen, Y. (Fudan University); Ding, Aaron Yi (TU Delft Information and Communication Technology); Wang, Xin (Fudan University); Hui, Pan (The Hong Kong University of Science and Technology; University of Helsinki)","","2023","Outstanding users (OUs) denote the influential, 'core' or 'bridge' users in online social networks. How to accurately detect and rank them is an important problem for third-party online service providers and researchers. Conventional efforts, ranging from early graph-based algorithms to recent machine learning-based approaches, typically rely on an entire social network's information. However, for privacy-conscious users or newly-registered users, such information is not easily accessible. To address this issue, we present DeepPick, a novel framework that considers both the generalization and specialization in the detection task of OUs. For generalization, we introduce deep neural networks to capture dynamic features of the users. For specialization, we leverage the traditional descriptive features to make use of public information about users. Extensive experiments based on real-world datasets demonstrate that our approach achieves a high efficacy of detection performance against the state-of-the-art.","Bridges; Computer science; Deep Neural Networks; Feature extraction; Integrated circuit modeling; Neural networks; Online Social Networks; Outstanding User Detection; Social networking (online); Task analysis","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Information and Communication Technology","","",""
"uuid:41d54d45-250a-4cfb-b5b5-4b129994adb2","http://resolver.tudelft.nl/uuid:41d54d45-250a-4cfb-b5b5-4b129994adb2","Integrated Sensing and Communication in UAV Swarms for Cooperative Multiple Targets Tracking","Zhou, Longyu (University of Electronic Science and Technology of China (UESTC)); Leng, Supeng (University of Electronic Science and Technology of China (UESTC)); Wang, Q. (TU Delft Embedded Systems); Liu, Qiang (University of Electronic Science and Technology of China (UESTC))","","2023","Various interconnected Internet of Things (IoT) devices have emerged, led by the intelligence of the IoT, to realize exceptional interaction with the physical world. In this context, UAV swarm-enabled Multiple Targets Tracking (UAV-MTT), which can sense and track mobile targets for many applications such as hit-and-run, is an appealing topic. Unfortunately, UAVs cannot implement real-time MTT based on the traditional centralized pattern due to the complicated road network environment. It is also challenging to realize low-overhead UAV swarm cooperation in a distributed architecture for the real-time MTT. To address the problem, we propose a cyber-twin-based distributed tracking algorithm to update and optimize a trained digital model for real-time MTT. We then design a distributed cooperative tracking framework to promote MTT performance. In the design, both short-distance and long-distance distributed tracking cooperation manners are first realized with low energy consumption in communication by integrating resources of sensing and communication. Resource integration promotes target sensing efficiency with a highly successful tracking ratio as well. Theoretical derivation proves our algorithmic convergence. Hardware-in-the-loop simulation results demonstrate that our proposed algorithm can remarkably save 65.7% energy consumption in communication compared to other benchmarks while efficiently promoting 20.0% sensing performance.","Integrated sensing and communication; UAV swarm; Target tracking; cyber-twin","en","journal article","","","","","","","","2023-10-05","","","Embedded Systems","","",""
"uuid:1300c1d6-d3e6-4c4c-8c1a-41893b4bba8e","http://resolver.tudelft.nl/uuid:1300c1d6-d3e6-4c4c-8c1a-41893b4bba8e","HPAKE: Honey Password-authenticated Key Exchange for Fast and Safer Online Authentication","Li, Wenting (Peking University); Wang, Ping (National Engineering Research Center for Software Engineering); Liang, K. (TU Delft Cyber Security)","","2023","Password-only authentication is one of the most popular secure mechanisms for real-world online applications. But it easily suffers from a practical threat - password leakage, incurred by external and internal attackers. The external attacker may compromise the password file stored on the authentication server, and the insider may deliberately steal the passwords or inadvertently leak the passwords. So far, there are two main techniques to address the leakage: Augmented password-authentication key exchange (aPAKE) against insiders and honeyword technique for external attackers. But none of them can resist both attacks. To fill the gap, we propose the notion of <italic>honey PAKE (HPAKE)</italic> that allows the authentication server to detect the password leakage and achieve the security beyond the traditional bound of aPAKE. Further, we build an HPAKE construction on the top of the honeyword mechanism, honey encryption, and OPAQUE which is a standardized aPAKE. We formally analyze the security of our design, achieving the insider resistance and the password breach detection. We implement our design and deploy it in the real environment. The experimental results show that our protocol only costs 71.27 ms for one complete run, within 20.67 ms on computation and 50.6 ms on communication. This means our design is secure and practical for real-world applications.","Password; honeyword; leakage detection; password-authenticated key exchange","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-08-24","","","Cyber Security","","",""
"uuid:1b2be59d-96be-4a86-a3b4-487653ced666","http://resolver.tudelft.nl/uuid:1b2be59d-96be-4a86-a3b4-487653ced666","AnyoneNet: Synchronized Speech and Talking Head Generation for Arbitrary Persons","Wang, X. (TU Delft Multimedia Computing; Xi’an Jiaotong University; Northwestern Polytechnical University); Xie, Qicong (Northwestern Polytechnical University); Xie, Lei (Northwestern Polytechnical University); Zhu, Jihua (Xi’an Jiaotong University); Scharenborg, O.E. (TU Delft Multimedia Computing)","","2023","Automatically generating videos in which synthesized speech is synchronized with lip movements in a talking head has great potential in many human-computer interaction scenarios. In this paper, we present an automatic method to generate synchronized speech and talking-head videos on the basis of text and a single face image of an arbitrary person as input. In contrast to previous text-driven talking head generation methods, which can only synthesize the voice of a specific person, the proposed method is capable of synthesizing speech for any person. Specifically, the proposed method decomposes the generation of synchronized speech and talking head videos into two stages, i.e., a text-to-speech (TTS) stage and a speech-driven talking head generation stage. The proposed TTS module is a face-conditioned multi-speaker TTS model that gets the speaker identity information from face images instead of speech, which allows us to synthesize a personalized voice on the basis of the input face image. To generate the talking head videos from the face images, a facial landmark-based method that can predict both lip movements and head rotations is proposed. Extensive experiments demonstrate that the proposed method is able to generate synchronized speech and talking head videos for arbitrary persons, in which the timbre of the synthesized voice is in harmony with the input face, and the proposed landmark-based talking head method outperforms the state-of-the-art landmark-based method on generating natural talking head videos.","speech synthesis; talking head generation; avatar; facial landmark","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-01","","","Multimedia Computing","","",""
"uuid:a9eb38a0-04db-4585-a9ec-e846beeeb882","http://resolver.tudelft.nl/uuid:a9eb38a0-04db-4585-a9ec-e846beeeb882","An Introduction to the Application of Marine Controlled-Source Electromagnetic Methods for Natural Gas Hydrate Exploration","Li, Y. (TU Delft Applied Geophysics and Petrophysics; Beijing University of Technology; Peking University); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Werthmüller, D. (TU Delft Geoscience and Engineering); Wang, Lipeng (Beihang University); Lu, Hailong (Beijing Normal University)","","2023","Natural gas hydrates have been an unconventional source of energy since the beginning of this century. Gas-hydrate-filled reservoirs show higher resistivity values compared with water-filled sediments. Their presence can be detected using marine controlled-source electromagnetic methods. We classify acquisition configurations into stationary and moving receiver configurations, which are described in terms of the design group, the operational details, and where they have been used successfully in the field for natural gas hydrate exploration. All configurations showed good numerical results for the detection of a 700 m long gas hydrate reservoir buried 200 m below the seafloor, but only the stationary configurations provided data that can be used to estimate the horizontal boundaries of the resistive part of the reservoir when the burial depth is known from seismic data. We discuss the operational steps of the configurations and provide the steps on how to choose a suitable configuration. Different CSEM configurations were used together with seismic data to estimate the edge of the gas hydrate reservoir and the total volume of the gas hydrates, to optimize the drilling location, to increase production safety, and to improve geological interpretations. It seems that CSEM has become a reliable method to aid in the decision-making process for gas hydrate reservoir appraisal and development.","marine electromagnetic; natural gas hydrates; exploration; resistivity","en","journal article","","","","","","","","","","Geoscience and Engineering","Applied Geophysics and Petrophysics","","",""
"uuid:ffbfdafd-758d-4ada-993a-c1a330732f95","http://resolver.tudelft.nl/uuid:ffbfdafd-758d-4ada-993a-c1a330732f95","Robustness Analysis of Platoon Control for Mixed Types of Vehicles","Wang, Yixia (University of Chinese Academy of Sciences); Lin, Shu (University of Chinese Academy of Sciences); Wang, Yibing (Zhejiang University); De Schutter, B.H.K. (TU Delft Delft Center for Systems and Control); Xu, Jungang (University of Chinese Academy of Sciences)","","2023","Currently, with the development of driving technologies, driverless vehicles gradually are becoming more and more available. Therefore, there would be a long period of time during which self-driving vehicles and human-driven vehicles coexist. However, for a mixed platoon, it is hard to control the formation due to the existence of the manual vehicles resulting in weak robustness and slow consensus rate on this system of platoons because of uncertainties caused by human factors for manual vehicles. In order to solve this problem, we establish models of mixed platoons with mixed types of connected and automated vehicles (CAVs), human-driven vehicles (HDVs) and HDVs without the vehicle awareness device (HDVWs). We subsequently design <inline-formula> <tex-math notation=""LaTeX"">$\mathcal{H}_\infty$</tex-math> </inline-formula> controllers for the mixed platoons to realize the formation consensus. In addition, we use the <inline-formula> <tex-math notation=""LaTeX"">$\mathcal{H}_\infty$</tex-math> </inline-formula> norm of mixed platoons as the control objective investigating the robustness of the control algorithms in alleviating the platoon uncertainties. Furthermore, conditions are proved to maintain the stability of the mixed platoons, and the stability is analyzed based on the variation of the penetration rate of the manual vehicles. Finally, we formulate conditions for parameters according to the definition of string stability to avoid the collisions of vehicles. The results in this study are tested with simulations and suggest that the presented controllers can ensure the consensus of mixed platoons under uncertainties."," $\mathcal{H}_\infty$ control; Adaptation models; Automobiles; High-temperature superconductors; mixed traffic flow; Robustness; Stability criteria; Traffic network control; Uncertainty; Vehicles","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","Delft Center for Systems and Control","","","",""
"uuid:e419a842-d1e5-419b-bafb-fe70974b8605","http://resolver.tudelft.nl/uuid:e419a842-d1e5-419b-bafb-fe70974b8605","Simulation-to-real generalization for deep-learning-based refraction-corrected ultrasound tomography image reconstruction","Zhao, Wenzhao (University Heidelberg); Fan, Yuling (University Heidelberg); Wang, Hongjian (Donghua University); Gemmeke, Hartmut (Karlsruhe Institut für Technologie); van Dongen, K.W.A. (TU Delft ImPhys/Medical Imaging; TU Delft ImPhys/Van Dongen goup); Hopp, Torsten (Karlsruhe Institut für Technologie); Hesser, Jürgen (University Heidelberg)","","2023","Objective. The image reconstruction of ultrasound computed tomography is computationally expensive with conventional iterative methods. The fully learned direct deep learning reconstruction is promising to speed up image reconstruction significantly. However, for direct reconstruction from measurement data, due to the lack of real labeled data, the neural network is usually trained on a simulation dataset and shows poor performance on real data because of the simulation-to-real gap.Approach. To improve the simulation-to-real generalization of neural networks, a series of strategies are developed including a Fourier-transform-integrated neural network, measurement-domain data augmentation methods, and a self-supervised-learning-based patch-wise preprocessing neural network. Our strategies are evaluated on both the simulation dataset and real measurement datasets from two different prototype machines.Main results. The experimental results show that our deep learning methods help to improve the neural networks' robustness against noise and the generalizability to real measurement data.Significance. Our methods prove that it is possible for neural networks to achieve superior performance to traditional iterative reconstruction algorithms in imaging quality and allow for real-time 2D-image reconstruction. This study helps pave the path for the application of deep learning methods to practical ultrasound tomography image reconstruction based on simulation datasets.","deep learning; Fourier transform; measurement domain; refraction-corrected ultrasound tomography; simulation-to-real generalization","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-27","","","ImPhys/Medical Imaging","","",""
"uuid:2a099239-a2af-44dc-949c-eae73d60132a","http://resolver.tudelft.nl/uuid:2a099239-a2af-44dc-949c-eae73d60132a","A Generic Framework for Multiscale Simulation of High and Low Enthalpy Fractured Geothermal Reservoirs under Varying Thermodynamic Conditions","Wang, Y. (TU Delft Numerical Analysis; TU Delft Geoscience and Engineering; China University of Geosciences); Hosseinimehr, S.M. (TU Delft Numerical Analysis; TU Delft Geoscience and Engineering); Marelis, A.A. (TU Delft Civil Engineering & Geosciences); Hajibeygi, H. (TU Delft Reservoir Engineering)","","2023","We develop a multiscale simulation strategy, namely, algebraic dynamic multilevel (ADM) method, for simulation of fluid flow and heat transfer in fractured geothermal reservoirs under varying thermodynamic conditions. Fractures with varying conductivities are modeled using the projection-based embedded discrete fracture model (pEDFM) in an explicit manner. The developed ADM method allows the fine-scale system to be mapped to a discrete domain with an adaptive grid resolution via the use of the restriction and prolongation operators. The developed framework is used a) to investigate the impacts of formulations with different primary variables on the simulation results, and b) to assess the performance of ADM in a high-enthalpy reservoir by comparing the simulation results against those obtained from fine-scale grids. Results show that the two formulations produce similar results in the case of single-phase flow, which indicates that the molar formulation is a favorable option that can be applied to varying thermodynamic conditions. Moreover, the ADM can provide accurate solutions with only a fraction of fine-scale grids, e.g., for the studied case, the maximum error is by average 1.3 with only 42% of active cells, thereby improving the computational efficiency. This is promising for applying the developed method to field-scale geothermal systems.","geothermal energy; mass and heat transfer; multiscale simulation","en","journal article","","","","","","","","","Civil Engineering & Geosciences","Geoscience and Engineering","Numerical Analysis","","",""
"uuid:8f3788d8-4501-4f95-86a2-32d3ee19cc42","http://resolver.tudelft.nl/uuid:8f3788d8-4501-4f95-86a2-32d3ee19cc42","A Streamline-Guided Dehomogenization Approach for Structural Design","Wang, Junpeng (Technische Universität München); Westermann, Rüdiger (Technische Universität München); Wu, J. (TU Delft Materials and Manufacturing)","","2023","We present a novel dehomogenization approach for the efficient design of high-resolution load-bearing structures. The proposed approach builds upon a streamline-based parametrization of the design domain, using a set of space-filling and evenly spaced streamlines in the two mutually orthogonal direction fields that are obtained from homogenization-based topology optimization. Streamlines in these fields are converted into a graph, which is then used to construct a quad-dominant mesh whose edges follow the direction fields. In addition, the edge width is adjusted according to the density and anisotropy of the optimized orthotropic cells. In a number of numerical examples, we demonstrate the mechanical performance and regular appearance of the resulting structural designs and compare them with those from classic and contemporary approaches.","Topology optimization; dehomogenization","en","journal article","","","","","","","","2023-06-12","","","Materials and Manufacturing","","",""
"uuid:65bd0389-148b-47c5-8b74-67cdfaa701ce","http://resolver.tudelft.nl/uuid:65bd0389-148b-47c5-8b74-67cdfaa701ce","Numerical Study of Percolation and Seepage Behaviors in Ion-Adsorption-Type Rare Earth Ore Leaching Process","Dianyu, E. (Jiangxi University of Science and Technology); Su, Zhongfang (Jiangxi University of Science and Technology); Zeng, Jia (Jiangxi University of Science and Technology); Yang, Liuyimei (Chinese Academy of Sciences); Li, Jing (Monash University); Xu, Qiang (Xi’an Jiaotong University); Wang, L. (TU Delft Resources & Recycling); Cui, Jiaxin (Jiangxi University of Science and Technology)","","2023","Ionic rare earth ore is a type of featured rare earth ore in China. Its mining process suffers from a long leaching cycle and considerable consumption of leaching agents. Improving mining efficiency requires a sound physical understanding of the leaching process. In this study, the CFD-based numerical model is used to analyze the physical process of leaching through porous media formed by particles. The simulation results indicate that a lower packing porosity and smaller particles packed granular porous medium result in much larger energy dissipation during seepage, and the energy dissipation increases with seepage velocity. It is found that when the seepage velocity increases to a certain high value, the energy dissipation exceeds the value predicted by Darcy’s law, which is mainly caused by liquid turbulence. Additionally, the effect of particle shape is examined. The results show that the granular medium composed of prolate particles causes larger energy dissipation than oblate particles, and spherical particles play the least role. This phenomenon may result from the particle shape affecting the area of the frontal contact surface between particles and liquid. The results provide new insights into the fundamental understanding of percolation and seepage behaviors in the ion-adsorption-type rare earth ore leaching process.","","en","journal article","","","","","","","","","","","Resources & Recycling","","",""
"uuid:607d3aa7-870a-479e-aa70-56709aee326f","http://resolver.tudelft.nl/uuid:607d3aa7-870a-479e-aa70-56709aee326f","Public participation and consensus-building in urban planning from the lens of heritage planning: A systematic literature review","Foroughi, M. (TU Delft Heritage & Architecture); de Andrade, Bruno (TU Delft Heritage & Architecture); Pereira Roders, A. (TU Delft Heritage & Architecture); Wang, T. (TU Delft Design & Construction Management)","","2023","Public participation has been growing in both theory and practice of urban planning, including heritage planning. The reasoning is to facilitate the involvement of a broader group of stakeholders, beyond experts. More specifically, for heritage planning, participation could enable consensus-building on defining the significance of heritage, namely attributes (the resources that should be listed as heritage), and values (the reasons that attributes are important). However, there is not yet a holistic understanding of the influencing factors behind consensus-building in the participatory planning processes for cultural heritage. To evaluate existing research from this angle, a systematic literature review was conducted on peer-reviewed articles using the Scopus database. As most of the studies focuse on urban planning, this research examines the factors influencing consensus-building in the participatory planning process applied to urban and heritage planning and reflects on the applicability of these factors in heritage planning. The main factors were identified inductively and grouped into two categories: 1) public participation: actors, methods, and levels of public participation, and 2) consensus: approaches, and conflicts. The relations between these factors and their frequencies are investigated using statistical analysis methods, namely frequency analysis, independent-samples t-test, and Spearman correlation. The literature confirms that urban planning has applied more diverse methods and tools for public participation compared to studies in the field of heritage planning, and could inspire heritage planning. Conflict is recognized as an intertwined concept with consensus which is considered either as a challenge or as a necessity for an inclusive decision-making. By proposing a framework integrating these factors and sub-factors and illustrating their relationships, this research could also be useful for decision-makers and practitioners to better tailor the public participation process and means to implement it, considering the relevant factors involved.","Public participation; Consensus; Attribute; Conflict; Value; Cultural heritage","en","journal article","","","","","","","","","","","Heritage & Architecture","","",""
"uuid:2de89733-b611-4e11-9403-9b97d9a7fa63","http://resolver.tudelft.nl/uuid:2de89733-b611-4e11-9403-9b97d9a7fa63","A Novel High-temperature Pressure Sensor Based on Graphene Coated by Si3N4","Zeng, Simei (Beijing Jiaotong University); Tang, Chenggang (Beijing Jiaotong University); Hong, H. (TU Delft Electronic Components, Technology and Materials); Yuan, Fang (Beijing Jiaotong University); Li, Yuning (Beijing Jiaotong University); Wang, Yuqiang (Beijing Jiaotong University); Kong, Lingbing (Beijing Jiaotong University); Sun, Jingye (Beijing Jiaotong University); Zhu, Mingqiang (Beijing Jiaotong University); Deng, Tao (Beijing Jiaotong University)","","2023","The high-temperature pressure sensors have wide applications in aerospace, petroleum, geothermal exploration, automotive electronics, and other fields. However, the traditional silicon-based pressure sensors are restricted to pressure measurement under 120~{\circ }\text{C} and cannot be satisfied to measure the pressure of various gases or liquids in high temperature and other harsh environments. This article proposes a novel high-temperature pressure sensor based on graphene, in which a rectangular cavity is applied to improve the piezoresistive characteristics of the sensor. The unique of this sensor is that the graphene is coated by the silicon nitride (Si3N4) membrane, which could avoid the oxidation of graphene in high temperature and increase the temperature tolerance range. The sensor was placed at various temperatures ( 50~{\circ }\text{C} - 420~{\circ }\text{C} ) to explore the temperature characteristics, achieving a maximal temperature coefficient of resistance (TCR) of 0.322% {\circ }\text{C}{-{1}}. Moreover, the sensor with a 64 \times 9\,\,\mu \text{m}{{2}} cavity has a high pressure sensitivity of 5.32\times 10{-{4}} kPa {-{1}} , enabling a wide range from 100 kPa to 10 Pa. Experimental results indicate that the proposed sensor possesses superior pressure sensitivity, a wide pressure detection range, and a high-temperature tolerance of 420~{\circ }\text{C} , which provides new insight into fabricating high-temperature pressure sensors based on graphene and creates more applications in different fields.","Graphene; high-temperature; Si3N4; piezoresistive characteristic","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-08-01","","","Electronic Components, Technology and Materials","","",""
"uuid:9df91cb9-7af3-449d-b8a2-e25fbb59d83c","http://resolver.tudelft.nl/uuid:9df91cb9-7af3-449d-b8a2-e25fbb59d83c","Investigation of Unclamped Inductive Switch Characteristics in 4H-SiC MOSFETs With Different Cell Topologies","Wu, Huan (Chongqing University); Luo, Houcai (Chongqing University); Zhang, Jingping (Chongqing University); Zheng, Bofeng (Chongqing University); Lang, Lei (Chongqing University); Wang, Zeping (Chongqing University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Chen, Xianping (Chongqing University)","","2023","To investigate the unclamped inductive switch (UIS) characteristics, 1200 V silicon carbide (SiC) planar MOSFETs with four cell topologies of linear, current sharing linear, square, and hexagon are designed and manufactured. The experimental platform was built and tested. The results show that the single pulse avalanche energy density of the linear cell topology is 1.69 times higher than that of the square and 1.49 times that of the hexagon. Further, the UIS process is simulated by using physical simulation, which shows that the avalanche energy was concentrated near the corner of the P-base region in the UIS mode. From this, the avalanche energy distribution differences of the four cell topologies were analyzed and compared. A theoretical model of avalanche heating per unit area is proposed, which shows that the avalanche energy density is inversely proportional to the proportion of avalanche energy concentration region. This study may contribute to the cell topology design of SiC MOSFETs under the application scenario with high avalanche reliability requirements.","Avalanche; cell topologies; failure analysis; silicon carbide (SiC) planar MOSFET; unclamped inductive switch (UIS) test","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-10","","","Electronic Components, Technology and Materials","","",""
"uuid:ffb732e6-4bb0-4066-a243-7f0efedab9aa","http://resolver.tudelft.nl/uuid:ffb732e6-4bb0-4066-a243-7f0efedab9aa","Interpreting the effectiveness of antioxidants to increase the resilience of asphalt binders: A global interlaboratory study","Adwani, Dheeraj (The University of Texas at Austin); Sreeram, Anand (The University of Texas at Austin); Pipintakos, Georgios (Universiteit Antwerpen); Mirwald, Johannes (Technische Universität Wien); Wang, Yudi (University of Illinois at Urbana-Champaign); Hajj, Ramez (University of Illinois at Urbana-Champaign); Jing, R. (TU Delft Pavement Engineering); Bhasin, Amit (The University of Texas at Austin)","","2023","The design and use of antioxidant additives to reduce or slow down the aging of asphalt binders can bring about tremendous benefits to the asphalt industry. Despite many isolated and scattered research efforts showing mixed results, the application of this science to engineering-based solutions has been limited due to variability in results and conflicting data available. This work presents the results from a global interlaboratory study to test the effectiveness of promising antioxidant additives, namely kraft lignin, calcium hydroxide, zinc diethyldithiocarbamate and phenothiazine to increase the resilience of asphalt binders and provide insights towards understanding the complex intricacies between chemistry and rheology. Specifically, seven different binders from various geographical regions in the world i.e., Texas (USA), Vienna (Austria), Illinois (USA), Antwerp (Belgium), and Delft (Netherlands) were blended with the antioxidants at two proportions. Subsequently, the chemical and rheological properties of the blends were evaluated using Fourier transform infrared (FTIR) spectroscopy and dynamic shear rheometer (DSR). The results indicate that although some antioxidants may reduce oxidation based chemical indices, their effect on rheology is more complicated and possibly related to unique physicochemical interactions in each binder. From a macro-perspective, zinc diethyldithiocarbamate showed promising results with a good correlation between rheology and chemistry for the majority of the binders. These additives or other additives with the same working principles should be investigated further. Additionally, significant research efforts must also be directed towards approaches aimed at understanding mechanisms of interaction and relating results with specific binder compositions.","Antioxidants; Aging; Binder Chemistry; Resilience; Oxidation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Pavement Engineering","","",""
"uuid:a576fcee-2b86-4344-ae7d-602099a52088","http://resolver.tudelft.nl/uuid:a576fcee-2b86-4344-ae7d-602099a52088","Frequency Tracking Method and Compensation Parameters Optimization to Improve Capacitor Deviation Tolerance of the Wireless Power Transfer System","Wang, Yi (Beijing Jiaotong University); Yang, Zhongping (Beijing Jiaotong University); Lin, Fei (Beijing Jiaotong University); Dong, J. (TU Delft DC systems, Energy conversion & Storage); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2023","Compensation capacitors are naturally susceptible to manufacturing defects and aging effects, leading to the degraded performance of a wireless power transfer (WPT) system. This article focuses on the compensation parameters optimization during the design stage and control strategy during the operation phase to improve the inherent capacitor error tolerance of the WPT system. The Sobol sensitivity method is applied to rank the importance of deviations of three capacitors on the transfer characteristics, and then the method of tracking the secondary resonance frequency is proposed. The numerical method is applied to find the optimal compensation parameters, with the constraint that the output voltage change caused by the shift of the designed compensation condition is limited to be less than ±5%. Experimental results show that with the proposed frequency tracking method and compensation parameter optimization, the deviation tolerance index is decreased from 0.485 to 0.363, showing an improvement of 25.2%, and the minimum power factor is increased from 0.78 to 0.89. Besides, the characteristics of constant primary coil current and voltage gain are almost not affected.","Wireless power transfer; compensation errors; detuning tolerance; frequency tracking; parameter optimization","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-04","","","DC systems, Energy conversion & Storage","","",""
"uuid:1066745a-5361-4246-874b-defe7921c8f7","http://resolver.tudelft.nl/uuid:1066745a-5361-4246-874b-defe7921c8f7","Diagnostic modeling of the shoreline variation along the Jiangsu Coast, China","Kuai, Y. (TU Delft Coastal Engineering); Aarninkhof, S.G.J. (TU Delft Hydraulic Engineering); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2023","Intertidal flats are of great socio-economic and ecological importance in defending the coastal cities from flooding, providing resources for land reclamations and habits for wildlife. On the intertidal flats, milder profiles are usually featured with finer sediment. However, we find the opposite relationship between the alongshore variation in intertidal slope and sediment grain size on the intertidal flat along the Jiangsu Coast. With a conceptual figure of the hydrodynamics and shoreline evolution on this coast, we hypothesize that the unexpected pattern is caused by the alongshore gradient in hydrodynamic forcing. In order to test our hypothesis, we carry out a series of numerical model simulations in a highly schematized manner to investigate the real mechanism behind this unexpected pattern. Through the analysis, we find that only the southwards coarsening pattern is inconsistent with the shoreline evolution pattern. This inconsistency is not induced by alongshore hydrodynamic gradient, and can only be explained by different sediment provenances. We also find that the alongshore shoreline evolution pattern is not only determined by the alongshore gradient in hydrodynamic forcing, but also influenced by the alongshore variation in bed composition. In the erosion/sedimentation transition zone, the bed composition factor plays the major role.","Intertidal flat; Beach slope; Sediment grain-size; Bed composition; Jiangsu Coast","en","journal article","","","","","","","","","","Hydraulic Engineering","Coastal Engineering","","",""
"uuid:c8de2434-d5fb-4037-bd0a-4ff08de7aefc","http://resolver.tudelft.nl/uuid:c8de2434-d5fb-4037-bd0a-4ff08de7aefc","Molecular dynamics simulation and experimental validation on the interfacial diffusion behaviors of rejuvenators in aged bitumen","Ren, S. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Gao, Y. (TU Delft Pavement Engineering); Jing, R. (TU Delft Pavement Engineering); Lin, P. (TU Delft Pavement Engineering); Erkens, S. (TU Delft Pavement Engineering); Wang, H. (University of Nottingham)","","2023","This study aims to multiscale investigate the effects of rejuvenator type, temperature, and aging degree of bitumen on the diffusion behaviors of rejuvenators (bio-oil BO, engine-oil EO, naphthenic-oil NO, and aromatic-oil AO) in aged binders. The molecular dynamics (MD) simulation method is performed to detect the molecular-level diffusion characteristics of rejuvenators and predict their diffusion coefficient (D) parameters. At an atomic scale, the mutual but partial interfacial diffusion feature between rejuvenators and aged bitumen molecules is observed. Moreover, Fick’s Second Law well fits the concentration distribution of rejuvenator molecules in aged bitumen. The magnitude for D values of four rejuvenators varies from 10-11 to 10-10 m2/s, and the diffusive capacity order is BO > EO > NO > AO. Meanwhile, diffusion tests and dynamic shear rheometer (DSR) characterizations are employed to validate the MD simulation outputs. The experimental results in magnitude and order of D values agree well with MD simulation outputs. Lastly, the increased aging degree of bitumen exhibits a negative impact on the molecular diffusivity of BO, EO, and NO rejuvenators, while the D value of AO molecules enlarges as the aging level deepens. The underlying mechanism may be composed of the free volume fraction in aged bitumen and the intermolecular force between rejuvenator and aged bitumen molecules, which differs remarkably for various rejuvenators.","Diffusion behavior; Rejuvenator; Aged bitumen; Molecular dynamics simulation; Experimental validation; Influence factors","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:bffad56e-83c8-4951-b41e-200f7f21b7a4","http://resolver.tudelft.nl/uuid:bffad56e-83c8-4951-b41e-200f7f21b7a4","Using Real Building Energy Use Data to Explain the Energy Performance Gap of Energy-Efficient Residential Buildings: A Case Study from the Hot Summer and Cold Winter Zone in China","Wang, Xia (Southwestern University of Finance and Economics); Yuan, Jiachen (Southwestern University of Finance and Economics); You, K. (TU Delft Design & Construction Management); Ma, Xianrui (Southwest University); Li, Zhaoji (Chongqing University)","","2023","The International Energy Agency (IEA) emphasizes that using real building energy use data (RBEUD) to reflect the actual condition of buildings and inform policy-making is the most effective way to reduce buildings’ carbon emissions. However, based on IEA’s evaluation, regional and national building stock data are limited and lacking. Especially for China, the lack of RBEUD in buildings has limited our ability to address the energy performance gap (EPG). In this research, EPG refers to the difference between regulated energy consumption by design standards and actual energy usage. EPG makes it difficult to develop buildings that are energy-efficient. Therefore, this study aims to gather and analyze RBEUD in order to understand the role of occupants’ behavior in explaining the EPG of energy-efficient residential buildings in China. The results suggest that the actual consumption of residential buildings is less than 1/5–1/3 of the theoretical limits. The heat pump and air conditioner’s actual schedules and setpoint settings are the significant drivers that explain the EPG. In addition, the presentation of a database of 1128 households provides actual usage behavior parameters for policy-makers to improve the accuracy of building energy forecasting models.","real building energy use data; energy performance gap; energy-efficient residential buildings; occupants’ behavior","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:5c22034c-22bc-40d9-904f-07ae4f8b20c0","http://resolver.tudelft.nl/uuid:5c22034c-22bc-40d9-904f-07ae4f8b20c0","Nonlinear Robust Control and Observation for Aeroelastic Launch Vehicles with Propellant Slosh in a Turbulent Atmosphere","Mooij, E. (TU Delft Astrodynamics & Space Missions); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics)","","2023","This paper focuses on the attitude control and propellant slosh suppression of aeroelastic launch vehicles in a turbulent atmosphere. For a five-degree pitch-angle block command, the tracking performance of the selected Incremental Non-Linear Dynamic Inversion Sliding Mode Controller (INDI-SMC) shows excellent tracking performance. However, turbulence still inevitably leads to oscillatory behaviour in the swivel command. Various filter designs have been implemented to improve the smoothness of INDI-SMC. Using either a notch or band-pass filter in the sensor-feedback loops of pitch angle and pitch rate only marginally reduced the swivel oscillations, but did not solve the problem for the rigid-body control. For the flexible launcher with slosh dynamics, filtering of the sensor-feedback signals reduced the oscillations in swivel command, and elastic and slosh motion significantly, but could not completely remove them. The preliminary design of a rigid-body state observer has been included, and the results show that the INDI-SMC controller remains stable in the presence of engine dynamics, sloshing, flexible modes, input errors due to the use of rigid-body and slosh-state observers, while flying in a turbulent wind field.","","en","conference paper","","","","","","","","","","","Astrodynamics & Space Missions","","",""
"uuid:d88fc5ef-192f-4ce6-9341-f323c3ff0d16","http://resolver.tudelft.nl/uuid:d88fc5ef-192f-4ce6-9341-f323c3ff0d16","Handling Quality Improvements for the Flying-V Aircraft using Incremental Nonlinear Dynamic Inversion","van Overeem, S. (Student TU Delft); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics); van Kampen, E. (TU Delft Control & Simulation)","","2023","Considerable growth in the number of passengers and cargo transported by air is predicted. Moreover, aircraft noise and climate impact become increasingly important factors in aircraft design. These existing challenges in aviation boost interest in the design of innovative aircraft configurations. One of these configurations is a V-shaped flying wing named the Flying-V. This work aims at developing a flight control system for the Flying-V that can be used to improve the stability and handling qualities of the aircraft. Prior work shows that the Flying-V is not able to adhere to all stability and handling quality requirements at the forward and aft center of gravity location during cruise and approach. This paper illustrates how an Incremental Nonlinear Dynamic Inversion flight control system can be used to improve the stability and handling qualities of the aircraft. Furthermore, the robustness of the flight control system is assessed by analysing the effects of aerodynamic uncertainty on the attitude tracking error of the Flying-V. Upon implementation of the flight control system, this research shows that the eigenmodes become stable. Besides that, the flight control system is proved to be robust against aerodynamic uncertainty.","","en","conference paper","","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:d6c3b16c-8f55-4d49-bca0-4383784912e8","http://resolver.tudelft.nl/uuid:d6c3b16c-8f55-4d49-bca0-4383784912e8","Manifold Learning of Nonlinear Airfoil Aerodynamics with Dimensionality Reduction","Vasudevan, S. (TU Delft Aerospace Structures & Computational Mechanics); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics)","","2023","This paper aims to explore the advantages offered by machine learning (ML) for dimensionality reduction of nonlinear transonic aerodynamics. Three ML techniques are evaluated in terms of their ability to generate interpretable low-dimensional manifolds of the transient pressure distributions over a NACA4412 airfoil equipped with a flap. These ML techniques are Kernel Principle Component Analysis (kPCA), Locally Linear Embedding (LLE), and t-distributed Stochastic Neighbourhood Embedding (t-SNE). Initial investigations are also carried out to evaluate the performance of Artificial Neural Networks (ANNs). Three transient aerodynamic test cases are evaluated. First, a static aerodynamic transient analysis. Second, pitching and heaving airfoils in terms of prescribed sinusoidal displacements. Lastly, the airfoil geometry is adapted to include a flap under sinusoidal actuation. The snapshots forming the ground truth are obtained from unsteady CFD simulations. The preliminary results of this study reveal that patterns exist in low-dimensional nonlinear manifolds. Furthermore, unsupervised learning techniques are seen to outperform supervised neural networks in terms of both training cost and reconstruction accuracy. Promising reconstruction capabilities are observed with unsupervised learning.","","en","conference paper","","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:65284622-f89d-41cb-a3ad-57034d5bb9a5","http://resolver.tudelft.nl/uuid:65284622-f89d-41cb-a3ad-57034d5bb9a5","Adopting BIM to Facilitate Dispute Management in the Construction Industry: A Conceptual Framework Development","Wang, Jinpeng (The University of Manchester); Zhang, Shang (Suzhou University of Science and Technology); Fenn, Peter (The University of Manchester); Luo, Xiaowei (City University of Hong Kong); Liu, Y. (TU Delft Integral Design & Management; Nanjing University); Zhao, Lilin (Loughborough University)","","2023","Previous studies revealed that Building Information Modeling (BIM) has the potential to reduce project uncertainties, design errors, change orders, and delays, which might facilitate achieving effective dispute management in the construction industry. However, research into the adoption of BIM to holistically enhance effective dispute management is limited compared with the plentiful BIM research in the construction management field. This study explored whether and how BIM adoption can help minimize the chronic problem of dispute in the industry. A structured critical literature review method was employed in this study which involved 102 papers in the fields of BIM and construction disputes. Nine main common causes of disputes (e.g., change order, design error, site problem, contractual problem, payment problem, and delay) and eight primary benefits of BIM application (e.g., improved visual management, design optimization, improved information management, and enhanced collaboration) were identified. A conceptual framework was developed illustrating the mechanism of adopting BIM to facilitate dispute management in the overall life cycle of construction projects. The framework indicates that design error, delay, and change order can be reduced most significantly by most of the BIM benefits, whereas improved visual management, improved information management, and enhanced collaboration are three of the most frequently adopted BIM benefits that can settle the majority of dispute causes. This study contributes to dispute management with a more holistic view of adopting BIM in the life cycle of construction projects, as illustrated in the conceptual framework. In addition, the identified common causes of disputes and primary benefits of BIM application are valuable for on future research in these two areas.","BIM benefits; Building Information Modeling (BIM); Conceptual framework; Dispute causes; Literature review","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Integral Design & Management","","",""
"uuid:9db9f1dd-bf55-4350-9737-ee4793ac7fb0","http://resolver.tudelft.nl/uuid:9db9f1dd-bf55-4350-9737-ee4793ac7fb0","Coupling Relationship between Rural Settlement Patterns and Landscape Fragmentation in Woodlands and Biological Reserves: A Case of Nanshan National Park","Li, Bo (Central South University China); Ouyang, Hao (Central South University China); Wang, T. (TU Delft Design & Construction Management); Dong, Tian (Central South University China)","","2023","Exploring the influence of settlement patterns on the landscape fragmentation in woodlands and biological reserves is key to achieving ecologically sustainable development. In this research, we chose the Nanshan National Park in Hunan Province, China, as a case study, to explore the influence mechanisms. First, we identified the biological reserves through the landscape security patterns of biological conservation. Second, we constructed a coupling coordination model to analyze the coupling relationship between the settlement patterns and landscape fragmentation in the woodlands and biological reserves. The analysis showed that, overall, the effect of the settlement area on the landscape fragmentation in the biological reserves was more pronounced, while the effect of the settlement spread and shape on the landscape fragmentation in the woodlands was more obvious. From a type-specific perspective, we analyzed the coupling relationship between the settlement patterns and (1) the landscape fragmentation in different woodlands and (2) the landscape fragmentation in the biological reserves, namely concerning Leiothrix lutea and Emberiza aureola. We found that the effect of the settlement patterns on the landscape fragmentation of the Leiothrix lutea biological reserve was more significant than that of the landscape fragmentation of its main habitat, the evergreen broad-leaved forest. The effect of settlement patterns on the landscape fragmentation of the Emberiza aureola biological reserve was more significant than that of the landscape fragmentation of its other habitats. In addition, the results demonstrated that the habitat protection of the woodlands was not a substitute for the systematic protection of biosecurity patterns. This research could assist in developing more efficient conservation measures for ecologically protected sites with rural settlements.","settlement pattern; woodland ecosystem; landscape security pattern; landscape fragmentation; coupling coordination degree","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:180d19a8-61c6-4652-8331-0f44941625cb","http://resolver.tudelft.nl/uuid:180d19a8-61c6-4652-8331-0f44941625cb","Multiple-axle box acceleration measurements at railway transition zones","Unsiwilai, S. (TU Delft Railway Engineering); Wang, L. (TU Delft Railway Engineering); Nunez, Alfredo (TU Delft Railway Engineering); Li, Z. (TU Delft Railway Engineering)","","2023","This paper presents a methodology for monitoring transition zones using responses of multiple-axle box acceleration (multi-ABA) measurements. The time–frequency characteristics of the vertical ABA signals from four wheelsets are analyzed. The major contributions are as follows. (1) We propose four key performance indicators (KPIs) to quantify local multi-ABA energy differences at different abutments, tracks, entrance and exit sides, and inner and outer rails. (2) The same dominant spatial frequencies are obtained with different measurement speeds, so the proposed method is suitable for multi-ABA systems mounted on operational trains. Transition zones at nine double-track railway bridges are selected as the case study. The KPIs indicate that (1) the energy differences between abutments are above 80% in three bridges; (2) two abutments show that the energy differences between tracks are higher than 100%; (3) three tracks have energy differences above 100% between the entrance and exit sides; and (4) the energy differences between rails are above 80% on three sides. Finally, using measurement with 7 years of difference, the KPIs and track quality index are discussed. These findings suggest that multi-ABA measurement can be used as a health condition monitoring method for railway transition zones to support condition-based maintenance.","Transition zones; Railway infrastructure; Axle box acceleration; Time-frequency analysis; Onboard measurement","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:bca73621-a728-4a15-96a8-4dfc69e17bf2","http://resolver.tudelft.nl/uuid:bca73621-a728-4a15-96a8-4dfc69e17bf2","The Impact of Covid-19 Pandemic on Value Migration Processes in the Real Estate Sector","Kowalski, Michał J. (Wrocław University of Technology); Wang, T. (TU Delft Design & Construction Management); Kazak, Jan K. (Wroclaw University of Environmental and Life Sciences)","","2023","The COVID-19 pandemic period brings huge uncertainty, especially for the real estate sector. On the one hand, restrictions on the mobility of a population, decline in travel demands, popularization of remote work and education models caused doubts among investors questioning the future of the sector and the functions of real estate. On the other hand, the large supply of cash after the first waves of the pandemic and the upcoming increase in inflation resulted in many investors boldly investing cash in real estate, considering them as assets of stable value. This research aims to analyze the processes of value migration among real estate companies listed on the Warsaw Stock Exchange during this turbulent process. We analyzed the changes in the main drivers of value and the migration rates of the real estate sector based on data for 2018, 2019, 2020 and Q3 2021. The first period of the pandemic is the time of the collapse of the main profitability factors, sales and profitability of sales decline in the entire sector. However, the financial pillars of the analyzed companies are stable and we are not seeing signs of liquidity problems or a significant increase in debt. The second year of the pandemic is a significant reflection of most of the drivers of value, often to levels higher than those observed before the pandemic. Investors seem to remain insensitive to turbulent changes in accounting measures of effectiveness. We observe the relative stability of market measures. The processes of the migration of values from and to the sector do not show significant changes when comparing the periods before and during the pandemic. We observe various intensities of the studied phenomena in various groups of the real estate segment.","COVID-19; real estate market; value migration","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:7b386549-93d1-499f-97cc-a0f55f41405a","http://resolver.tudelft.nl/uuid:7b386549-93d1-499f-97cc-a0f55f41405a","Machine learning assisted early anomaly detection of LEDs with spectral power distribution modeling","Liu, Minne (Fudan University); Ibrahim, Mesfin S. (New Territories); Wen, Minzhen (Fudan University); Li, Sheng (Shanhai Yaming Lighting Co.Ltd); Wang, An (Shanhai Yaming Lighting Co.Ltd); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Fan, J. (TU Delft Electronic Components, Technology and Materials; Fudan University; Chinese Academy of Sciences; Fudan Zhangjiang Institute,)","","2023","Spectral power distribution (SPD) is the radiation power intensity at different wavelengths, containing the most basic photometric and colorimetric performance of the illuminant, which is able to predict the lifetime of LEDs. This paper proposes an SPD model assisted by machine learning algorithms to detect the early failure of white LEDs. The SPD features of 3W high-power white LEDs were firstly extracted by the statistical models of Gaussian, Lorentz, and Asym2sig functions. An unsupervised learning method, principal component analysis (PCA), was then used to reduce the extracted features parameters’ dimensions. Next a K-nearest neighbor (KNN)-based method was used to detect LEDs’ anomalies by dividing the main cluster into groups, and estimating the distance from the center of mass of each cluster to the test point. The results showed the following: (1) for selected white LEDs, the Asym2sig function has a better fitting result than Gaussian and Lorentz functions; (2) machine learning methods can significantly assist in LED anomaly detection and can decrease the amount of anomaly detection time to 789.6 h, compared to the 1311 h when lumen maintenance degradation reaches 70% as required by IES TM21.","White LEDs; Spectral power distribution; Anomaly detection; Principal component analysis; K-nearest neighbor","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-24","","","Electronic Components, Technology and Materials","","",""
"uuid:6c35dcd3-b6e6-4e51-ae21-19c9bef49998","http://resolver.tudelft.nl/uuid:6c35dcd3-b6e6-4e51-ae21-19c9bef49998","Digital twin application in heritage facilities management: systematic literature review and future development directions","Hou, H. (The Hong Kong Polytechnic University); Lai, Joseph H.K. (The Hong Kong Polytechnic University); Wu, Hao (University of Melbourne); Wang, T. (TU Delft Design & Construction Management)","","2023","This paper aims to investigate the theoretical and practical links between digital twin (DT) application in heritage facilities management (HFM) from a life cycle management perspective and to signpost the future development directions of DT in HFM.
This state-of-the-art review was conducted using a systematic literature review method. Inclusive and exclusive criteria were identified and used to retrieve relevant literature from renowned literature databases. Shortlisted publications were analysed using the VOSviewer software and then critically reviewed to reveal the status quo of research in the subject area.
The review results show that DT has been mainly adopted to support decision-making on conservation approach and method selection, performance monitoring and prediction, maintenance strategies design and development, and energy evaluation and management. Although many researchers attempted to develop DT models for part of a heritage building at component or system level and test the models using real-life cases, their works were constrained by availability of empirical data. Furthermore, data capture approaches, data acquisition methods and modelling with multi-source data are found to be the existing challenges of DT application in HFM.
In a broader sense, this study contributes to the field of engineering, construction and architectural management by providing an overview of how DT has been applied to support management activities throughout the building life cycle. For the HFM practice, a DT-cum-heritage building information modelling (HBIM) framework was developed to illustrate how DT can be integrated with HBIM to facilitate future DT application in HFM. The overall implication of this study is that it reveals the potential of heritage DT in facilitating HFM in the urban development context.","Literature review; Digital twin; Built environment; Heritage life cycle; Facilities management","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-28","","","Design & Construction Management","","",""
"uuid:46e5884c-772a-4bef-b243-203a05fa15c2","http://resolver.tudelft.nl/uuid:46e5884c-772a-4bef-b243-203a05fa15c2","A Gradient-Descent Optimization Assisted Gray-Box Impedance Modeling of EV chargers","Wang, L. (TU Delft DC systems, Energy conversion & Storage); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2023","Extracting an electric vehicle (EV) charger's input impedance with the analytical model (white-box approach) or the frequency sweep (black-box approach) is limited by the parameter confidentiality or the measurement noise, respectively. To overcome these challenges, a gradient-descent (GD) optimization-based gray-box modeling approach is proposed. To start with, a sensitivity study on the analytical impedance model of an EV charger with a typical controller is carried out to identify the influential frequency range per controller and circuit parameter. On top of that, given an EV charger with unknown control and circuit information, a GD optimization-based algorithm for multiple parameter estimation is designed to identify the unknown controller and circuit parameters based on the measured impedance, by assuming the EV charger is using the typical controller. Then, an analytical input impedance of the black-box EV charger can be obtained. Moreover, the low-accuracy issue commonly encountered when estimating multiple parameters with GD optimization is mitigated with the proposed algorithm. Compared to pure frequency sweep, the proposed approach achieves a higher accuracy for the coupling impedance and a comparable accuracy for the diagonal impedance. The effectiveness of the proposed approach is validated by experimental results.","EV Charging; Power Quality; impedance modeling; Parameter Estimation; Gray Box Model; gradient-based optimization; Voltage Source Converter (VSC)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-17","","","DC systems, Energy conversion & Storage","","",""
"uuid:8af0030b-3c93-4b2b-8baa-b83faa49e1b9","http://resolver.tudelft.nl/uuid:8af0030b-3c93-4b2b-8baa-b83faa49e1b9","Black-Box Online Aerodynamic Performance Optimization for a Seamless Wing with Distributed Morphing","Ruland, Oscar (Student TU Delft); Mkhoyan, T. (TU Delft Arts & Crafts; TU Delft Aerospace Structures & Computational Mechanics); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics)","","2023","","Aerodynamic Performance; Aircraft Wing Design; Artificial Neural Network; Wind Tunnels; Optimization Algorithm; Newton Raphson Method; Zero Lift Drag Coefficient; Evolutionary Algorithm","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-04-20","","","Arts & Crafts","","",""
"uuid:95ea6576-69d7-4ecc-a0d7-35e616562253","http://resolver.tudelft.nl/uuid:95ea6576-69d7-4ecc-a0d7-35e616562253","Unprotected Left-Turn Behavior Model Capturing Path Variations at Intersections","Zhao, Jing (University of Shanghai for Science and Technology); Knoop, V.L. (TU Delft Transport and Planning); Sun, Jian (Tongji University); Ma, Zian (Tongji University); Wang, M. (TU Delft Transport and Planning; Technische Universität Dresden)","","2023","Path dispersion (the spatial distribution of vehicular paths) is an important feature of traffic flow inside intersections and differs from traffic flow running along traffic lanes at road segment, especially under conflicting movements. The path dispersion reflects the operational features of traffic flow and is related to driving behaviour, arrival flow patterns, layout design, and the traffic control and management scheme. This study aims to improve the understanding of the overall path dispersion of unprotected left-turns and the opposing through movement. A behavioural simulation model was established to represent the overall path dispersion. Human behaviours regarding vehicle trajectory planning with and without conflicting vehicles were modelled based on optimal control and integrated into the proposed discrete event simulation framework. The descriptive power and accuracy of the proposed simulation model were validated using empirical data. The effects of the spatial size of the intersection, crossing angle, and traffic volume on the path dispersion of the left-turn and through movement were explored based on numerical experiments. The results show that the proposed simulation model can represent the path dispersion of left-turn and opposing through movement well for both the calibrated intersections and newly added intersections without model parameter recalibration with an average error of 8.92%.","Path dispersion; driving behaviors; conflicting movements; intersections","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-03","","Transport and Planning","Transport and Planning","","",""
"uuid:adbb9b90-64aa-4c22-abd8-abeb79ff6426","http://resolver.tudelft.nl/uuid:adbb9b90-64aa-4c22-abd8-abeb79ff6426","Risk Quantification and Visualization Method for Loss-of-Control Scenarios in Flight","Wang, Guozhi (Air Force Engineering University); Pei, Binbin (Air Force Engineering University); Xu, Haojun (Air Force Engineering University); Lv, Maolong (Air Force Engineering University); Zhao, Z. (TU Delft Dataintensive Systems); Bu, Xiangwei (Air Force Engineering University)","","2023","This paper proposes a flight risk analysis method that combines risk assessment and visual deduction to study the causes of flight accidents, specifically the loss of control caused by failure factors. The goal is to explore the impact of these failure factors on loss-of-control events and illustrate the risk evolution under different scenarios in a clear and intuitive manner. To achieve this, the paper develops a failure scenario tree to guide flight simulations under different loss-of-control scenarios. The next step involves developing a multi-parameters risk assessment method that can quantify flight risk at each time step of the flight simulation. This assessment method uses entropy weight and a grey correlation algorithm to assign variable weights to the different parameters. Finally, the paper presents the visual deduction of the risk evolution process under different loss-of-control scenarios using a risk tree that concisely represents the time-series risk assessment results and failure logical chains. Taking three common failure factors (actuator failure, engine failure, and wing icing) as cases, the paper designs 25 different loss-of-control scenarios to demonstrate the flight risk analysis method. By comparing the risk evolution process under different loss-of-control scenarios, the paper explores the impact of the failure factors on flight safety. The analysis results indicate that this method combines risk analysis from both individual and global perspectives, enabling effective analysis of risk evolution in loss-of-control events.","loss of control; failure factors; risk quantitative assessment; risk visual deduction; failure scenario tree; risk tree","en","journal article","","","","","","","","","","","Dataintensive Systems","","",""
"uuid:e1dbe656-59a9-499e-994e-0880d393c53d","http://resolver.tudelft.nl/uuid:e1dbe656-59a9-499e-994e-0880d393c53d","Robustness of Network Controllability with Respect to Node Removals Based on In-Degree and Out-Degree","Wang, F. (TU Delft Network Architectures and Services); Kooij, Robert (TU Delft Network Architectures and Services; TNO)","","2023","Network controllability and its robustness have been widely studied. However, analytical methods to calculate network controllability with respect to node in- and out-degree targeted removals are currently lacking. This paper develops methods, based on generating functions for the in- and out-degree distributions, to approximate the minimum number of driver nodes needed to control directed networks, during node in- and out-degree targeted removals. By validating the proposed methods on synthetic and real-world networks, we show that our methods work reasonably well. Moreover, when the fraction of the removed nodes is below 10% the analytical results of random removals can also be used to predict the results of targeted node removals.","controllability; complex networks; node removals","en","journal article","","","","","","","","","","","Network Architectures and Services","","",""
"uuid:dbb0ea73-8281-4dbf-aca4-885d8ce72ff8","http://resolver.tudelft.nl/uuid:dbb0ea73-8281-4dbf-aca4-885d8ce72ff8","Temporal-topological properties of higher-order evolving networks","Ceria, A. (TU Delft Multimedia Computing); Wang, H. (TU Delft Multimedia Computing)","","2023","Human social interactions are typically recorded as time-specific dyadic interactions, and represented as evolving (temporal) networks, where links are activated/deactivated over time. However, individuals can interact in groups of more than two people. Such group interactions can be represented as higher-order events of an evolving network. Here, we propose methods to characterize the temporal-topological properties of higher-order events to compare networks and identify their (dis)similarities. We analyzed 8 real-world physical contact networks, finding the following: (a) Events of different orders close in time tend to be also close in topology; (b) Nodes participating in many different groups (events) of a given order tend to involve in many different groups (events) of another order; Thus, individuals tend to be consistently active or inactive in events across orders; (c) Local events that are close in topology are correlated in time, supporting observation (a). Differently, in 5 collaboration networks, observation (a) is almost absent; Consistently, no evident temporal correlation of local events has been observed in collaboration networks. Such differences between the two classes of networks may be explained by the fact that physical contacts are proximity based, in contrast to collaboration networks. Our methods may facilitate the investigation of how properties of higher-order events affect dynamic processes unfolding on them and possibly inspire the development of more refined models of higher-order time-varying networks.","OA-Fund TU Delft","en","journal article","","","","","","","","","","","Multimedia Computing","","",""
"uuid:baf784bd-ed99-4a1b-91f3-1360f1a7c502","http://resolver.tudelft.nl/uuid:baf784bd-ed99-4a1b-91f3-1360f1a7c502","Conflict-free train path planning using ATO timing points","Wang, Z. (TU Delft Transport and Planning); Quaglietta, E. (TU Delft Transport and Planning); Bartholomeus, Maarten (ProRail); Cunillera, A. (TU Delft Transport and Planning); Goverde, R.M.P. (TU Delft Transport and Planning)","","2023","Automatic Train Operation (ATO) is a technology to support or automate train driving for increasing service punctuality, energy efficiency and rail infrastructure capacity. Conflict-free train path planning is crucial to the effective deployment of ATO, which allows ATO-equipped trains to operate according to schedule with different train driving strategies. As different train driving strategies lead to various passing times, current planning practice is inadequate to avoid route conflicts as it only sets target arrival or passing times at stops or major junctions. Therefore, conflict-free train path planning needs the definition of a Train Path Envelope (TPE) that contains time targets or windows defined at discrete locations called timing points to tolerate schedule deviations due to different driving styles. The number and location of the timing points, as well as the associated time targets or windows, is a decision problem. This paper proposes a framework to design a robust set of timing points and their associated time windows in a TPE to enable operational conflict-free train path planning against the driving strategies utilised. This framework relies on a Train Path Slot model which extends the definition of TPE from time windows at a discrete set of locations to an integrated blocking time stairway pattern continuously defined across all locations over a train route. The Train Path Slot model considers three relevant train driving strategies, i.e., energy-efficient driving with or without coasting as well as minimum-time driving considering slight delays. A Linear Programming model is formulated to compute the conflict-free Train Path Slots as constraints for train operation. To meet the optimised Train Path Slots, we analyse several possible sets of timing points in a TPE that are only located at stops or signal positions along the train routes. Those timing point sets are then compared in terms of total Train Path Slot overlap time, capacity, energy efficiency and driving performance indicators. Our research supports infrastructure managers in resolving the imminent problem of timing point determination and TPE computation to reach their capacity goals. At the same time, it allows sufficient driving flexibility for railway undertakings.","ATO-over-ETCS; Automatic Train Operation; Train Path Envelope; Train driving strategies; Timing Point","en","abstract","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-28","","","Transport and Planning","","",""
"uuid:22efc57b-9411-4b75-b2b0-274858635660","http://resolver.tudelft.nl/uuid:22efc57b-9411-4b75-b2b0-274858635660","How Gaps are Created during Anticipation of Lane Changes","Chen, Kequan (Southeast University); Knoop, V.L. (TU Delft Transport and Planning); Liu, Pan (Southeast University); Li, Zhibin (Southeast University); Wang, Yuxuan (Southeast University)","","2023","The pre-insertion process called anticipation is an essential component of a lane-changing manoeuvre. There is little empirical research regarding the impact of anticipation. Thus, this paper aims to explore the behaviour of the new follower (NF) in the target lane when it encounters anticipation by using new trajectory datasets. The changing magnitude of the reaction pattern is proposed to identify the NF’s behaviour. We find that the anticipation significantly affects the NF’s movement in terms of gap creation and speed reduction. Then, we conduct a detailed analysis of critical variables to reveal their relationship with the NF’s behaviour. Following this, we develop binary logistic models to predict the NF’s behaviour, resulting in a good performance. It also suggests that the NF’s behaviour is highly related to the anticipation-related variables. The transferability test results show that this model can be directly used in different locations and times with satisfactory accuracy.","Anticipation behavilour; lane-changing impact; car-following behaviour; microscopic trajectory data","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Transport and Planning","","",""
"uuid:f6826895-fa1b-445b-9b45-a2eb20e6a338","http://resolver.tudelft.nl/uuid:f6826895-fa1b-445b-9b45-a2eb20e6a338","Interspecific competition shapes the structural stability of mutualistic networks","Wang, Xiangrong (Shenzhen University); Peron, Thomas (Universidade de São Paulo); Dubbeldam, J.L.A. (TU Delft Mathematical Physics); Kéfi, Sonia (Université de Montpellier; Santa Fe Institute); Moreno, Yamir (University of Zaragoza; CENTAI Institute)","","2023","Mutualistic networks, such as plant–pollinator networks, have attracted increasing attention in the ecological literature in the last decades, not only because of their fascinating natural history, but also because mutualistic interactions have been shown to play a key role in the maintenance of biodiversity. Although inter-specific competition has long been known to be a crucial driver of species coexistence as well, there is a lack of theory investigating the interplay between the structures of competitive and mutualistic networks when jointly considered. Here, we develop an analytical framework to study the structural stability — the range of conditions under which all species coexist stably, i.e. where the community is both feasible and stable — of ecological communities in which both mutualistic interactions between plants and pollinators and competitive interactions among plants and among pollinators are present. Using the structure of 50 real networks for mutualistic interactions, combined with analytical and numerical analyses, we show that the structure of the competitive network radically alters the necessary conditions for species coexistence in these communities. Our mathematical framework also allows to accurately characterize the structural stability of these systems. Moreover, we introduce a new metric that accurately links the network structures of competitive and mutualistic interactions to species coexistence. Our results highlight the joint role of the structures of different interaction types to understand the stability of ecological communities and facilitate the analysis of similar natural and artificial systems in which mutualism and competition coexist.","Mutualistic networks; Interspecific competition; Structural stability; Species coexistence","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:a73acffb-9714-49a4-9c20-dd20fd777838","http://resolver.tudelft.nl/uuid:a73acffb-9714-49a4-9c20-dd20fd777838","Experimental Testing and Constitutive Modelling of Pavement Materials","Liu, X. (TU Delft Pavement Engineering); Zhang, Yuqing (Aston University); You, Zhanping (Michigan Technological University); Wang, Linbing (University of Georgia); Zhou, Changhong (Guilin University of Electronic Technology)","","2023","","","en","contribution to periodical","","","","","","","","","","","Pavement Engineering","","",""
"uuid:b80ed31a-a13e-4760-9788-b0863aae053e","http://resolver.tudelft.nl/uuid:b80ed31a-a13e-4760-9788-b0863aae053e","Shear wave ultrasound elastography of the biceps brachii can be used as a precise proxy for passive elbow torque in individuals with hemiparetic stroke","Ellis, Michael D. (Northwestern University); Gurari, Netta (Northwestern University); Gerritsen, Ninette T.A. (Northwestern University); Lee, Sabrina M. (Northwestern University); Wang, Amy (Northwestern University); Dewald, J.P.A. (TU Delft Biomechatronics & Human-Machine Control; Northwestern University)","","2023","Muscle tissue is prone to changes in composition and architecture following stroke. Changes in muscle tissue of the extremities are thought to increase resistance to muscle elongation or joint torque under passive conditions. These effects likely compound neuromuscular impairments, exacerbating movement function. Unfortunately, conventional rehabilitation is devoid of precise measures and relies on subjective assessments of passive joint torques. Shear wave ultrasound elastography, a tool to measure muscle mechanical properties, may be readily available for use in the rehabilitation setting as a precise measure, albeit at the muscle-tissue level. To support this postulation, we evaluated the criterion validity of shear wave ultrasound elastography of the biceps brachii; we investigated its relationship with a laboratory-based criterion measure for quantifying elbow joint torque in individuals with moderate to severe chronic stroke. Additionally, we evaluated construct validity, with the specific sub-type of hypothesis testing of known groups, by testing the difference between arms. Measurements were performed under passive conditions at seven positions spanning the arc of elbow joint flexion-extension in both arms of nine individuals with hemiparetic stroke. Surface electromyography was utilized for threshold-based confirmation of muscle quiescence. A moderate relationship between the shear wave velocity and elbow joint torque was identified, and both metrics were greater in the paretic arm. Data supports the progression toward a clinical application of shear wave ultrasound elastography in evaluating altered muscle mechanical properties in stroke, while acknowledging that undetectable muscle activation or hypertonicity may contribute to the measurement. Shear wave ultrasound elastography may augment the conventional method of manually testing joint mobility by providing a high-resolution precise value. Tissue-level measurement may also assist in identifying new therapeutic targets for patient-specific impairment-based interventions.","criterion validity; joint torque; mechatronics; stroke; torque; ultrasound elastography","en","journal article","","","","","","","","","","","Biomechatronics & Human-Machine Control","","",""
"uuid:a525cd82-18a8-4752-84bf-5d10b393cac6","http://resolver.tudelft.nl/uuid:a525cd82-18a8-4752-84bf-5d10b393cac6","Numerical parametric evaluation of ultimate resistance of high-strength bolts","Li, Jie (Xi’an Jiaotong University); Xin, Haohui (Xi’an Jiaotong University); Wang, Zhiqiang (Shaanxi Construction Engineering Holdings Group Co., Ltd.); Veljkovic, M. (TU Delft Steel & Composite Structures); Bingzhen, Zhao (Shaanxi Construction Engineering Holdings Group Co., Ltd.); Zhao, Junjie (Shaanxi Construction Engineering Holdings Group Co., Ltd.); Correia, José A.F.O. (Universidade do Porto)","","2023","High strength bolts are widely used in the engineering field due to their good compressive properties. Accurate assessment of the ultimate capacity performance of high strength bolts under combined loading is essential to ensure the safety of steel structures in the connection zone. Existing studies are not sufficiently clear on the economic and condition-specific limits on the effects of various factors on high-strength bolts under complex stress conditions. In response to these problems, the aim of this paper is to analyse the effects of different factors on the load-bearing performance of high-strength bolts on the basis of numerical simulations. The mesoscale critical plastic strain (MCEPS) method was used on the model fracture and the accuracy of the model evaluation was verified. The effects of grade, type, diameter and bolt hole clearance on the ductile fracture behaviour of high-strength bolts were investigated. It was found that fully threaded bolts and through-hole clearances can mainly affect the load-bearing properties of high-strength bolts and increase the bolt's fracture-deformation capacity. The load-bearing performance of high-strength bolts under the influence of different factors was also compared with the Eurocode design (EC3) predictions.","Bolt diameter; Bolt grade; Bolt hole clearance; Bolt type; High-strength bolts","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-04","","","Steel & Composite Structures","","",""
"uuid:c2157d14-0363-4f95-92b9-03cb1331e544","http://resolver.tudelft.nl/uuid:c2157d14-0363-4f95-92b9-03cb1331e544","Intercity networks and urban performance: a geographical text mining approach","Tongjing, Wang (Universiteit Utrecht); Meijers, E.J. (TU Delft Urban Studies; Universiteit Utrecht); Bao, Ziyu; Wang, H. (TU Delft Multimedia Computing)","","2023","Compared to the burgeoning literature discussing the importance of agglomeration externalities for development, limited attention has been given to network externalities. This is largely due to limited data availability. We propose a general measure to proxy city network externalities based on toponym co-occurrences that indicate the relatedness between cities. This paper extracts intercity relationships based on the co-occurrence of Chinese place names on 2.5 billion webpages. We calculate and map absolute and relative network positions, which we use to explain urban labour productivity. We found that a stronger embeddedness in networks of cities is significantly and positively associated with urban productivity. Smaller cities benefit comparatively more from being well embedded in city networks, suggesting that these relations can compensate for a lack of agglomeration externalities. We also compare the importance for urban performance of city network externalities vis-à-vis agglomeration externalities. City network externalities turn out to be more important in explaining urban performance than agglomeration externalities. This calls for new theorizing on a relational approach to urban and regional development. Rather than stimulating further concentration of urbanization, our findings suggest that fostering relationships between cities is a viable alternative urban development strategy. We conclude with suggestions for a research agenda that delves deeper into city network externalities.","agglomeration externalities; China; City networks; labour productivity; regional development; urban system","en","journal article","","","","","","","","","","","Urban Studies","","",""
"uuid:d861b3c4-234d-4b00-810e-e42e667c0be7","http://resolver.tudelft.nl/uuid:d861b3c4-234d-4b00-810e-e42e667c0be7","Promising solutions for railway operations to cope with future challenges — Tackling COVID and beyond","Wang, Z. (TU Delft Transport and Planning); Aoun, J. (TU Delft Transport and Planning); Szymula, Christopher (Technische Universität Dresden); Bešinović, Nikola (TU Delft Transport and Planning; Technische Universität Dresden)","","2023","The COVID-19 pandemic has imposed a dramatic effect on the mobility habits of both passengers and freight in the rail sector. Since the relaxation of COVID-19 restrictions worldwide, rail transport has been revitalised gradually. However, the new normal emerges with unprecedented issues, such as changed travel behaviour, lost profits, and a lack of personnel. In this paper, we determine the arising challenges due to COVID-19 and pandemics in general and subsequently propose several solutions to tackle these challenges in rail transport. These solutions cover multidisciplinary aspects such as passenger demand management, freight demand management, service design, automation, decentralisation and advanced railway technologies. By reviewing the relevant literature on COVID-19, public transport and particularly rail transport, we synthesise and identify promising lines of research that should devote more attention to a more efficient, effective and sustainable rail transport service. This paper provides policymakers, researchers, railway infrastructure managers and undertakings with an overview and an outlook for the impacts of the pandemic crisis and similar situations. It supports decision-making with more evidence and facilitates rail transport to restore its performance and reach its societal goal.","Capacity management; COVID-19; Railway technology; Railways; Resilience","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:3b942384-88fd-4bfa-8bfa-a05e8eb2068c","http://resolver.tudelft.nl/uuid:3b942384-88fd-4bfa-8bfa-a05e8eb2068c","Distinctive sedimentary processes on two contrasting tidal flats of the Yellow River Delta","Xie, Weiming (East China Normal University); Sun, J. (TU Delft Coastal Engineering); Guo, Leicheng (East China Normal University); Xu, Fan (East China Normal University); Wang, Xianye (East China Normal University); Ji, Hongyu (East China Normal University); Fan, Yaoshen (Yellow River Conservancy Commission); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); He, Qing (East China Normal Univeristy)","","2023","Coastal tidal flats provide valuable ecosystems, but are highly sensitive to tidal dynamics, sea-level rise, and human activities. Tidal inundation depth and frequency are known to affect tidal flat morphodynamics. However, the causes, processes and extent remain uncertain, particularly given the associated changes in sediment availability. In this study, we monitored the hydrodynamics, sediment transport, and morphological changes on two tidal flats in the northern and southern parts of the Yellow River Delta, with contrasting tidal regimes. The data showed that longer inundation periods under diurnal tides gained additional sediment and deposition than under semi-diurnal tides, because of the associated increase in water depth and sediment availability. The wave impact increased at the site with a semi-diurnal tidal regime owing to the lower water depth, where a larger bed shear stress led to tidal flat erosion. These results indicated that the combination of tidal regime and the occurrence of powerful waves played a joint role in controlling bed erosion, sediment availability, and short-term tidal flat evolution. This has implications for coping with delta erosion by enhancing local sediment availability in diurnal tidal regions and restoring vegetation to attenuate waves in semi-diurnal regions of the Yellow River Delta.","tidal flat; hydrodynamics; sediment dynamics; inundation period; Yellow River Delta","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:4721619c-39a4-49d4-aec7-bfba11584a4c","http://resolver.tudelft.nl/uuid:4721619c-39a4-49d4-aec7-bfba11584a4c","Physics-Informed Neural Networks for Solving Forward and Inverse Problems in Complex Beam Systems","Kapoor, T. (TU Delft Railway Engineering); Wang, H. (TU Delft Railway Engineering); Nunez, Alfredo (TU Delft Railway Engineering); Dollevoet, R.P.B.J. (TU Delft Railway Engineering)","","2023","This article proposes a new framework using physics-informed neural networks (PINNs) to simulate complex structural systems that consist of single and double beams based on Euler–Bernoulli and Timoshenko theories, where the double beams are connected with a Winkler foundation. In particular, forward and inverse problems for the Euler–Bernoulli and Timoshenko partial differential equations (PDEs) are solved using nondimensional equations with the physics-informed loss function. Higher order complex beam PDEs are efficiently solved for forward problems to compute the transverse displacements and cross-sectional rotations with less than <inline-formula> <tex-math notation=""LaTeX"">$1e-3$</tex-math> </inline-formula>% error. Furthermore, inverse problems are robustly solved to determine the unknown dimensionless model parameters and applied force in the entire space–time domain, even in the case of noisy data. The results suggest that PINNs are a promising strategy for solving problems in engineering structures and machines involving beam systems.","Complex system; double-beam system; Euler–Bernoulli beam; physics-informed neural networks (PINNs); Timoshenko beam","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:0417087e-2e2e-4130-81eb-4de9a38b9b43","http://resolver.tudelft.nl/uuid:0417087e-2e2e-4130-81eb-4de9a38b9b43","Transit-Oriented Development in China: A Comparative Content Analysis of the Spatial Plans of High-Speed Railway Station Areas","Wang, B. (TU Delft Urban Development Management); de Jong, Martin (Fudan University; Erasmus Universiteit Rotterdam); van Bueren, Ellen (TU Delft Management in the Built Environment); Ersoy, A. (TU Delft Urban Development Management); Meng, Yanchun (Tsinghua University)","","2023","With rapid high-speed railway (HSR) developments in China, HSR-based transit-oriented development (TOD) has proliferated across the country. Although local governments claim that HSR station areas are planned according to TOD principles, some scholars argue that these station areas actually contribute to unsustainable development. This study investigates two main questions: (1) what success factors should be included in a TOD plan for HSR station areas? (2) to what extent are these factors considered in the plans of Chinese HSR station areas? To answer these questions, we use content analysis to compare spatial plans for 15 HSR station areas across China, triangulating the findings via in-depth interviews and field investigations. This study reveals that most of the factors in the plans for HSR station areas deviate from TOD principles, especially in small- and medium-sized cities. We find that Chinese local governments mainly use TODs as a tool to promote suburban expansion around HSR stations.","TOD; high-speed railway; station area; spatial plan; content analysis","en","journal article","","","","","","","","","","Management in the Built Environment","Urban Development Management","","",""
"uuid:7329ff8e-89e9-4e11-9b1e-9af8e1c106d1","http://resolver.tudelft.nl/uuid:7329ff8e-89e9-4e11-9b1e-9af8e1c106d1","On the Stochastic Model for InSAR Single Arc Point Scatterer Time Series","Brouwer, W.S. (TU Delft Mathematical Geodesy and Positioning); Wang, Y. (TU Delft Mathematical Geodesy and Positioning); van Leijen, F.J. (TU Delft Mathematical Geodesy and Positioning); Hanssen, R.F. (TU Delft Mathematical Geodesy and Positioning)","","2023","InSAR enables the estimation of displacements of (objects on) the earth's surface. To provide reliable estimates, both a stochastic and mathematical model are required. However, the intrinsic problem of InSAR is that both are unknown. Here we derive the Variance-Covariance Matrix (VCM) for double differenced phase observations for an arc, i.e., the phase difference between two points relative to a reference epoch. Using the Normalized Amplitude Dispersion we subdivide the time series in multiple partitions. The method results in a more realistic stochastic model, and consequently more realistic and reliable displacement parameters. The stochastic model also allows to make statements on the precision and reliability of the estimated parameters.","InSAR; parameter estimation; Point Scatterers; stochastic model","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-21","","","Mathematical Geodesy and Positioning","","",""
"uuid:bf642704-ee39-4d2e-93ba-3735bd79bc62","http://resolver.tudelft.nl/uuid:bf642704-ee39-4d2e-93ba-3735bd79bc62","基于分段步进式弹塑性格构模型的混凝土破坏过程细观模拟","Zhang, H. (Shandong University); Jin, Zuquan (Qingdao University of Technology); Jiang, Nengdong (Shandong University); Ge, Zhi (Shandong University); Schlangen, E. (TU Delft Materials and Environment); Ling, Yifeng (Shandong University); Šavija, B. (TU Delft Materials and Environment); Wang, Zheng (Shandong Hi-Speed Group)","","2023","The classically lattice model assumes the local elements behave elastic brittle, neglecting the ductility of the mortar matrix. This leads to the simulated load⁃displacement response more brittle than the realistic. To solve the aforementioned issue, a piece⁃wise approach was introduced to describe the elastic⁃plastic constitutive relation of lattice element. The fracture process and the load⁃displacement response were obtained through the sequentially⁃linear solution approach. The model was calibrated using the uniaxial tension and compression tests. It is found that the model can precisely simulate the fracture process and load⁃displacement response. Moreover, the model was used to model the size effect in uniaxial tension and the influence of the specimen’s slenderness and boundary confinement on the fracture behavior under compression. It offers a new theoretical method and approach for studying the fracture of concrete.","concrete; elastic⁃plastic constitutive relation; fracture process; lattice model; meso⁃scale","zh","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-25","","","Materials and Environment","","",""
"uuid:5a55bc8f-6258-47a3-89c4-622ae68f51fa","http://resolver.tudelft.nl/uuid:5a55bc8f-6258-47a3-89c4-622ae68f51fa","High entropy liquid electrolytes for lithium batteries","Wang, Q. (TU Delft RST/Storage of Electrochemical Energy); Zhao, C. (TU Delft RST/Storage of Electrochemical Energy); Wang, Jianlin (Chinese Academy of Sciences); Yao, Zhenpeng (Shanghai Jiao Tong University); Wang, Shuwei (Tsinghua University); Kumar, Sai Govind Hari (University of Toronto); Ganapathy, S. (TU Delft RID/TS/Instrumenten groep); Eustace, S.J. (TU Delft BT/Biocatalysis); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2023","High-entropy alloys/compounds have large configurational entropy by introducing multiple components, showing improved functional properties that exceed those of conventional materials. However, how increasing entropy impacts the thermodynamic/kinetic properties in liquids that are ambiguous. Here we show this strategy in liquid electrolytes for rechargeable lithium batteries, demonstrating the substantial impact of raising the entropy of electrolytes by introducing multiple salts. Unlike all liquid electrolytes so far reported, the participation of several anionic groups in this electrolyte induces a larger diversity in solvation structures, unexpectedly decreasing solvation strengths between lithium ions and solvents/anions, facilitating lithium-ion diffusivity and the formation of stable interphase passivation layers. In comparison to the single-salt electrolytes, a low-concentration dimethyl ether electrolyte with four salts shows an enhanced cycling stability and rate capability. These findings, rationalized by the fundamental relationship between entropy-dominated solvation structures and ion transport, bring forward high-entropy electrolytes as a composition-rich and unexplored space for lithium batteries and beyond.","OA-Fund TU Delft","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:94925cc9-6365-4e49-bb3c-554905372779","http://resolver.tudelft.nl/uuid:94925cc9-6365-4e49-bb3c-554905372779","A risk-based driver behaviour model","Yuan, Y. (TU Delft Transport and Planning; Technische Universität München); Wang, X. (Queen Mary University of London); Calvert, S.C. (TU Delft Transport and Planning); Happee, R. (TU Delft Intelligent Vehicles); Wang, M. (Technische Universität Dresden)","","2023","Current driver behaviour models (DBMs) are primarily designed for the general driver population under specific scenarios, such as car following or lane changing. Hence DBMs capturing individual behaviour under various scenarios are lacking. This paper presents a novel method to quantify individual perceived driving risk in the longitudinal and lateral directions using risk thresholds capturing the time headway and time to line crossing. These are integrated in a risk-based DBM formulated under a model predictive control (MPC) framework taking into account vehicle dynamics. The DBM assumes drivers to operate as predictive controllers jointly optimising multiple criteria, including driving risk, discomfort, and travel inefficiency. Simulation results in car following and passing a slower vehicle demonstrate that the DBM predicts plausible behaviour under representative driving scenarios, and that the risk thresholds are able to reflect individual driving behaviour. Furthermore, the proposed DBM is verified using empirical driving data collected from a driving simulator, and the results show it is able to accurately generate vehicle longitudinal and lateral control matching individual human drivers. Overall, this model can capture individual risk perception behaviour and can be applied to the design and assessment of intelligent vehicle systems.","driver behaviour model; human factors; path planning; risk perception; vehicle dynamics and control","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:0b282417-db94-454e-b27b-2a502a9f8b7c","http://resolver.tudelft.nl/uuid:0b282417-db94-454e-b27b-2a502a9f8b7c","Author Correction: Plastic waste discharge to the global ocean constrained by seawater observations","Zhang, Yanxu (Nanjing University); Wu, Peipei (Nanjing University); Xu, Ruochong (Nanjing University); Wang, Xuantong (Nanjing University); Lei, Lili (Nanjing University); Schartup, Amina T. (Scripps Institution of Oceanography); Peng, Yiming (Nanjing University); Pang, Qiaotong (Nanjing University); Luijendijk, Arjen (TU Delft Coastal Engineering; Deltares)","","2023","Correction to: Nature Communications, published online 13 March 2023 The original version of this Article contained an error in Fig. 2, in which c was incorrectly described as “middle scenario” where it should have been described as “low scenario”. The correct version of Fig. 2 is: (Figure presented.) which replaces the previous incorrect version: (Figure presented.) This has been corrected in both the PDF and HTML versions of the Article.","","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:0aaf8c23-fe1b-4159-8ced-cfe351468d22","http://resolver.tudelft.nl/uuid:0aaf8c23-fe1b-4159-8ced-cfe351468d22","Exploring the impact of select anchor groups for norbornadiene/quadricyclane single-molecule switches","Ghasemi, Shima (Chalmers University of Technology); Ornago, L. (TU Delft QN/van der Zant Lab); Liasi, Zacharias (University of Copenhagen); van der Poel, S. (TU Delft QN/van der Zant Lab); Hölzel, Helen (ICMAB-CSIC); Wang, Zhihang (University of Cambridge); van der Zant, H.S.J. (TU Delft QN/van der Zant Lab); Lara-Avila, Samuel (Chalmers University of Technology); Moth-Poulsen, Kasper (Chalmers University of Technology; Universitat Politecnica de Catalunya; Catalan Institution for Research and Advanced Studies (ICREA); ICMAB-CSIC)","","2023","To achieve the ultimate limit of device miniaturization, it is necessary to have a comprehensive understanding of the structure–property relationship in functional molecular systems used in single-molecule electronics. This study reports the synthesis and characterization of a novel series of norbornadiene derivatives capped with thioether and thioester anchor groups. Utilizing the mechanically controllable break junction technique, the impact of these capping groups on conductance across single-molecule junctions is investigated. Among the selection of anchor groups, norbornadiene capped with thioacetate and tert-butyl groups exhibits higher conductance (G ≈ 4 × 10−4 G0) compared to methyl thioether (G ≈ 2 × 10−4 G0). Electronic transmission through the considered set of single-molecule junctions has been simulated. The computational results for electron transport across these junctions align closely with the experimental findings, with the thioacetate- and tert-butyl-substituted systems outperforming the methyl thioether-capped derivative. In terms of junction stability, the methyl thioether-capped system is the most resilient, maintaining consistent conductance even after approximately 10 000 cycles. Meanwhile, the likelihood of observing molecular plateaus in both the thioacetate- and tert-butyl-substituted systems declines over time. These findings substantially advance both the design and understanding of functional molecular systems in the realm of single-molecule electronics, particularly in the context of molecular photoswitches.","","en","journal article","","","","","","","","","","","QN/van der Zant Lab","","",""
"uuid:b3225378-c513-4da3-a544-adb279207226","http://resolver.tudelft.nl/uuid:b3225378-c513-4da3-a544-adb279207226","Publisher Correction to Particle fusion of super-resolution data reveals the unit structure of Nup96 in Nuclear Pore Complex (Scientific Reports, (2023), 13, 1, (13327), 10.1038/s41598-023-39829-5)","Wang, W. (TU Delft ImPhys/Computational Imaging; TU Delft ImPhys/Rieger group); Jakobi, A. (TU Delft BN/Arjen Jakobi Lab); Wu, Yu‑Le ‑L (European Molecular Biology Laboratory Heidelberg); Ries, Jonas (University of Vienna); Stallinga, S. (TU Delft ImPhys/Imaging Physics); Rieger, B. (TU Delft ImPhys/Computational Imaging; TU Delft ImPhys/Rieger group)","","2023","Correction to: Scientific Reports, published online 16 August 2023 The original version of this Article contained an error in the upper inset of Figure 4, where the atomic model was missing. The original Figure 4 and accompanying legend appear below. (Figure presented.) Overlay of the fluorophore positions from the SMLM particle fusion data (pink) and the SNAP-tag derived from the cryo-EM data (purple). For our overall SMLM emitters (pink), the lateral distance between a unit are 9.1 nm for NR and 10.0 nm for CR. The axial distances between a unit are 2.4 nm for NR and 1.2 nm for CR. The SNAP tags (purple) have lateral distances between a unit of 11.6 nm for NR and 11.5 nm for CR as well as axial distances of 2.5 nm for NR and 2.9 nm for CR. The original Article has been corrected.","","en","journal article","","","","","","","","","","ImPhys/Imaging Physics","ImPhys/Computational Imaging","","",""
"uuid:aa3824ca-3432-4dde-a363-16b4c30c3309","http://resolver.tudelft.nl/uuid:aa3824ca-3432-4dde-a363-16b4c30c3309","Recovering Power Grids Using Strategies Based on Network Metrics and Greedy Algorithms","Wang, F. (TU Delft Network Architectures and Services); Cetinay, Hale (Stedin); He, Zhidong (DS Information Technology); Liu, L. (TU Delft Intelligent Electrical Power Grids); Van Mieghem, P.F.A. (TU Delft Network Architectures and Services); Kooij, Robert (TU Delft Quantum & Computer Engineering; TNO)","","2023","For this study, we investigated efficient strategies for the recovery of individual links in power grids governed by the direct current (DC) power flow model, under random link failures. Our primary objective was to explore the efficacy of recovering failed links based solely on topological network metrics. In total, we considered 13 recovery strategies, which encompassed 2 strategies based on link centrality values (link betweenness and link flow betweenness), 8 strategies based on the products of node centrality values at link endpoints (degree, eigenvector, weighted eigenvector, closeness, electrical closeness, weighted electrical closeness, zeta vector, and weighted zeta vector), and 2 heuristic strategies (greedy recovery and two-step greedy recovery), in addition to the random recovery strategy. To evaluate the performance of these proposed strategies, we conducted simulations on three distinct power systems: the IEEE 30, IEEE 39, and IEEE 118 systems. Our findings revealed several key insights: Firstly, there were notable variations in the performance of the recovery strategies based on topological network metrics across different power systems. Secondly, all such strategies exhibited inferior performance when compared to the heuristic recovery strategies. Thirdly, the two-step greedy recovery strategy consistently outperformed the others, with the greedy recovery strategy ranking second. Based on our results, we conclude that relying solely on a single metric for the development of a recovery strategy is insufficient when restoring power grids following link failures. By comparison, recovery strategies employing greedy algorithms prove to be more effective choices.","power grids; network resilience; network recoverability","en","journal article","","","","","","","","","","Quantum & Computer Engineering","Network Architectures and Services","","",""
"uuid:4e67290a-dd15-4d21-8cb8-7cc3b549ff54","http://resolver.tudelft.nl/uuid:4e67290a-dd15-4d21-8cb8-7cc3b549ff54","Vacuum Deposited Perovskites with a Controllable Crystal Orientation","Yan, J. (TU Delft Photovoltaic Materials and Devices); Stickel, L.S. (TU Delft Photovoltaic Materials and Devices; Georg-August-University); van den Hengel, L. (TU Delft ChemE/Opto-electronic Materials); Wang, H. (TU Delft Photovoltaic Materials and Devices); Ravi Anusuyadevi, P. (TU Delft Team Arjan Mol); Kooijman, A.M. (TU Delft Team Arjan Mol); Liu, X. (TU Delft ChemE/O&O groep); Ibrahim, B. (TU Delft ChemE/O&O groep); Mol, J.M.C. (TU Delft Team Arjan Mol); Taheri, P. (TU Delft Team Peyman Taheri); Mazzarella, L. (TU Delft Photovoltaic Materials and Devices); Isabella, O. (TU Delft Photovoltaic Materials and Devices); Savenije, T.J. (TU Delft ChemE/Opto-electronic Materials)","","2023","The preferential orientation of the perovskite (PVK) is typically accomplished by manipulation of the mixed cation/halide composition of the solution used for wet processing. However, for PVKs grown by thermal evaporation, this has been rarely addressed. It is unclear how variation in crystal orientation affects the optoelectronic properties of thermally evaporated films, including the charge carrier mobility, lifetime, and trap densities. In this study, we use different intermediate annealing temperatures Tinter between two sequential evaporation cycles to control the Cs0.15FA0.85PbI2.85Br0.15 orientation of the final PVK layer. XRD and 2D-XRD measurements reveal that when using no intermediate annealing primarily the (110) orientation is obtained, while when using Tinter = 100 °C a nearly isotropic orientation is found. Most interestingly for Tinter > 130 °C a highly oriented PVK (100) is formed. We found that although bulk electronic properties like photoconductivity are independent of the preferential orientation, surface related properties differ substantially. The highly oriented PVK (100) exhibits improved photoluminescence in terms of yield and lifetime. In addition, high spatial resolution mappings of the contact potential difference (CPD) as measured by KPFM for the highly oriented PVK show a more homogeneous surface potential distribution than those of the nonoriented PVK. These observations suggest that a highly oriented growth of thermally evaporated PVK is preferred to improve the charge extraction at the device level.","","en","journal article","","","","","","","","","","","Photovoltaic Materials and Devices","","",""
"uuid:014217d4-e681-42af-87f2-9466c786c793","http://resolver.tudelft.nl/uuid:014217d4-e681-42af-87f2-9466c786c793","FedNaWi: Selecting the Befitting Clients for Robust Federated Learning in IoT Applications","Zhu, R. (TU Delft Embedded Systems); Yang, M. (TU Delft Embedded Systems); Yang, J. (TU Delft Web Information Systems); Wang, Q. (TU Delft Embedded Systems)","","2023","Federated Learning (FL) is an important privacy-preserving learning paradigm that is expected to play an essential role in the future Intelligent Internet of Things (IoT). However, model training in FL is vulnerable to noise and the statistical heterogeneity of local data across IoT clients. In this paper, we propose FedNaWi, a “Go Narrow, Then Wide” client selection method that speeds up the FL training, achieves higher model performance, while requiring no additional data or sensitive information transfer from clients. Our method first selects reliable clients (i.e., going narrow) which allows the global model to quickly improve its performance and then includes less reliable clients (i.e., going wide) to exploit more IoT data of clients to further improve the global model. To profile client utility, we introduce a unified Bayesian framework to model the client utility at the FL server, assisted by a small amount of auxiliary data. We conduct extensive evaluations with 5 state-of-the-art FL methods, on 3 IoT tasks and under 7 different types of label and feature noise. We build an FL testbed with 38 IoT nodes (20 nodes run on Raspberry Pi 4B and 18 nodes run on Jetson Nano) for the evaluation. Our results show that FedNaWi improves the FL accuracy substantially and significantly reduces energy consumption. In particular, FedNaWi improves the accuracy from 35% to 75% in the non-IID Dirichlet setting, and reduces the average energy consumption by 55%.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-23","","","Embedded Systems","","",""
"uuid:37ef1cde-31b3-49f8-8848-51a4da2a332b","http://resolver.tudelft.nl/uuid:37ef1cde-31b3-49f8-8848-51a4da2a332b","Enhancing Indoor-to-Outdoor mmWave Communication with Transparent Amplifying Intelligent Surface","Liu, Bin (Katholieke Universiteit Leuven); Wang, Q. (TU Delft Embedded Systems); Pollin, Sofie (Katholieke Universiteit Leuven)","","2023","This paper presents a novel transparent amplifying intelligent surface (TAIS) architecture for uplink enhancement in indoor-to-outdoor mmWave communications. The TAIS is an amplifier-based transmissive intelligent surface that can refract and amplify the incident signal, instead of only refracting it with adjustable phase shift by most passive reconfigurable intelligent surfaces (RIS). With advanced indium tin oxide film and printing technology, TAIS can be fabricated on the windows without any visual effects. This paper primarily focuses on exploiting the TAIS-based architecture to boost the uplink spectral efficiency (SE) in indoor-to-outdoor mmWave communications. By jointly optimizing the TAIS's phase shift matrix and transmit power of the user equipment, the uplink SE can be maximized by exploiting the nonlinearity in the TAIS's amplification process. The key point is that we drive the optimal phase shift matrix that maximizes the SE and deduces its closed-form representation. The SE maximization is then proved to be transferred to the transmit power optimization problem. Another important aspect is that we design a low-complexity algorithm to solve the problem using the difference of convex programming. Simulations show that our proposed TAIS can increase the SE by up to 32.6% as compared to its alternative methods.","Reconfigurable intelligent surface; transparent amplifying intelligent surface (TAIS); spectral efficiency; indoorto-outdoor communication; nonlinear amplification","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-23","","","Embedded Systems","","",""
"uuid:99904b2c-d551-4682-ae9a-a1c845c3a196","http://resolver.tudelft.nl/uuid:99904b2c-d551-4682-ae9a-a1c845c3a196","Critical Short Circuit Ratio of an EV Charging System","Wang, L. (TU Delft DC systems, Energy conversion & Storage); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Xiao, J. (TU Delft DC systems, Energy conversion & Storage); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2023","The critical short circuit ratio (CSCR), as an important metric for grid stability evaluation, is not clearly defined in the literature. Aimed at clarifying the misunderstandings, the paper compares the different CSCR definitions. Moreover, CSCR reduction-oriented design is studied for electric vehicle chargers. Simulations verify the analysis.","EV charging; Stability Analysis; Weak Grids; controller design","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-08","","","DC systems, Energy conversion & Storage","","",""
"uuid:751dc447-830d-4c96-a68d-31aa34f1386b","http://resolver.tudelft.nl/uuid:751dc447-830d-4c96-a68d-31aa34f1386b","Analysis of Injury Severity of Drivers Involved Different Types of Two-Vehicle Crashes Using Random-Parameters Logit Models with Heterogeneity in Means and Variances","Wu, Qiang (Nantong University); Song, Dongdong (Beijing Jiaotong University); Wang, Chenzhu (Southeast University); Chen, Fei (Southeast University); Cheng, Jianchuan (Southeast University); Easa, Said M. (Toronto Metropolitan University); Yang, Y. (TU Delft Transport and Planning); Yang, Wenchen (Broadvision Engineering Consultants Co., Ltd.; Yunnan Key Laboratory of Digital Communications)","","2023","This study proposes random-parameters multinomial logit models, with heterogeneity in means and variances, to explore the differences in the factors influencing injury severities of drivers involved in different types of two-vehicle crashes. The models are verified using crash data from the United Kingdom (UK) over three years (2016–2018). Three types of crashes are separately identified (car-car, car-truck, and truck-truck crashes). In this study, a wide variety of potential variables, including the driver, vehicle, road, and environmental characteristics, are considered, with two possible injury-severity outcomes: severe and slight injury. The results show that unobserved heterogeneity existed for young drivers in both car-car and truck-truck crash models and the 30 mph speed limit in the three separate models. Remarkably variations are observed in crashes involving different types of vehicles. The driver’s age and gender, speeding, sideswipes, presence of junctions, weekdays, unlit, and weather conditions significantly impact driver-injury severities in various types of vehicle crashes. These findings are expected to help policymakers seek to improve highway safety and implement proper safety countermeasures.","","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:dfa43129-6d90-46e4-8f4e-6003f100a584","http://resolver.tudelft.nl/uuid:dfa43129-6d90-46e4-8f4e-6003f100a584","Groyne-Induced Effects on Channel-Shoal Exchange and Saltwater Intrusion in Estuarine Environments","Zhou, Zaiyang (East China Normal University); Ge, Jianzhong (Institute of Eco-Chongming; East China Normal University); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Deltares; East China Normal University); Kuai, Y. (TU Delft Coastal Engineering); Ding, Pingxing (East China Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2023","Existing knowledge about groyne-induced effects is primarily based on riverine or coastal environments where salinity gradients are absent or limited. However, in estuaries, salinity gradients drive physical processes such as longitudinal and lateral residual flows. The effect of groynes is much more complex because they can modulate channel hydrodynamics and directly affect lateral salinity gradients. In this study, an idealized model is applied to investigate the effects of groyne layouts in estuarine environments, including effects on (1) channel hydrodynamics, (2) lateral water exchange, (3) Coriolis effects, and (4) saltwater intrusion. Model results show that the aspect ratio (the width of groyne fields to the length of groynes) of groyne fields plays an important role. Groynes also induce asymmetry of lateral flows, for example, increasing near-bottom shoal-to-channel flows during low water slack. The aspect ratio has opposite effects on horizontal and vertical components of water exchange. A large aspect ratio strengthens horizontal exchange and weakens density-driven currents. For a large-scale groyne field (several kilometers), Coriolis effects introduce a substantial difference in exchange mechanisms along the north and south banks. A medium range of aspect ratio (2.0-3.0) leads to the strongest saltwater intrusion during both neap and spring tides.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-20","","","Environmental Fluid Mechanics","","",""
"uuid:e2727946-0d8d-4631-a99e-f094786a5a25","http://resolver.tudelft.nl/uuid:e2727946-0d8d-4631-a99e-f094786a5a25","Rail wear rate on the Belgian railway network: a big-data analysis","Vernaillen, T. (TU Delft Railway Engineering; Infrabel); Wang, L. (TU Delft Railway Engineering); Nunez, Alfredo (TU Delft Railway Engineering); Dollevoet, R.P.B.J. (TU Delft Railway Engineering); Li, Z. (TU Delft Railway Engineering)","","2023","This paper presents a big data-based analysis of the rail wear of the whole Belgian railway network measured in 2012 and 2019. Wear rates are reported, discussed, and quantitatively formulated as functions of critical factors in terms of curve radius, annual tonnage (rail age), high rail in curves, an average from both rails in straight tracks at rail top (vertical wear) and gauge corner (45° wear) and for steel grade R200 and R260. The influence of preventive grinding is also analysed. The wear rates are derived in an aggregated manner for the whole network. The wear rates do not show significant change with changes in rolling stock over the years, implying that the wear rates could also hold for other networks. It is found that R200 shows, on average, a 34% higher wear rate than R260. Also, the wear rate per tonnage is lower for high-loaded tracks. Thus, time is a relevant factor in explaining the wear evolution of low-loaded tracks; for instance, the effect of corrosion may have an important role. The paper provides statistically significant information that can be used for wear modelling, understanding and treating rolling contact fatigue based on the wear rate and developing tailored rail maintenance strategies.","big data; country-wide assessment; Rail; wear rate","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:ec09aba4-ffc2-4a52-a859-3d6e9285d267","http://resolver.tudelft.nl/uuid:ec09aba4-ffc2-4a52-a859-3d6e9285d267","Coverage and Capacity Analysis for Football Player's Bodycam with Cell-Free Massive MIMO","Hersyandika, Rizqi (Katholieke Universiteit Leuven); Rossanese, Marco (NEC Laboratories Europe); Lutu, Andra (Telefonica Research); Yang, Miao (Katholieke Universiteit Leuven; University of Twente); Wang, Q. (TU Delft Embedded Systems); Pollin, Sofie (Katholieke Universiteit Leuven)","","2023","This paper studies a promising use case of a private 5G network for the sports industry: wearable bodycams and sensors in a football match. This use case requires a reliable and dedicated massive MIMO network to provide uniform coverage with a high capacity in the whole pitch area. The coverage of co-located and distributed (cell-free) massive MIMO, differing in the configuration of base station antenna placement inside the stadium, are evaluated through ray tracing using a 3D stadium model and players' mobility dataset. The results give insight into how distributed antennas inside the stadium should be deployed to enhance the uniform coverage of moving wearable devices. Besides that, the uplink capacity performance and the impact of channel aging on the capacity are also evaluated. The results demonstrate the advantages and disadvantages of different base station antenna distribution strategies in terms of coverage, capacity and channel aging impact.","massive MIMO; cell-free; coverage; channel aging; private 5G; sports","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-23","","","Embedded Systems","","",""
"uuid:807fc6b5-2562-4a92-92f7-ece3887e5bd2","http://resolver.tudelft.nl/uuid:807fc6b5-2562-4a92-92f7-ece3887e5bd2","Virtual Impedance Control for Load Sharing and Bus Voltage Quality Improvement","Xiao, J. (TU Delft DC systems, Energy conversion & Storage); Wang, L. (TU Delft DC systems, Energy conversion & Storage); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2023","This paper proposes a virtual impedance reshaping strategy to share active and harmonic power while promoting the PCC voltage quality. Moreover, the suggested method is resilient to cyber-attacks and immune to communication interruption and delay. Furthermore, it significantly reduces the communication burden. Experiments verify the effectiveness.","AC-DC microgrid; Cyber attack; Cyber physical system; Decentralized control structure; Voltage Source Converters (VSCs)","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-08","","","DC systems, Energy conversion & Storage","","",""
"uuid:d196b424-3c51-4ed4-a370-5e62a822668c","http://resolver.tudelft.nl/uuid:d196b424-3c51-4ed4-a370-5e62a822668c","Guest Editorial Special Issue on Sensing and Machine Learning for Automotive Perception","Santra, Avik (Infineon Technologies, North America); Pandharipande, Ashish (NXP Semiconductors); Wang, Pu Perry (Mitsubishi Electric Research Laboratories); Gurbuz, Sevgi Zubeyde (University of South Alabama); Ibanez-Guzman, Javier (Group Renault); Cheng, Chih Hong (Fraunhofer Iks); Dauwels, J.H.G. (TU Delft Signal Processing Systems); Li, Guofa (Chongqing University)","","2023","","","en","contribution to periodical","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-12-18","","","Signal Processing Systems","","",""
"uuid:2cba0f7e-b1ae-4e69-a0f1-153df866891c","http://resolver.tudelft.nl/uuid:2cba0f7e-b1ae-4e69-a0f1-153df866891c","Federated Synthetic Data Generation with Stronger Security Guarantees","Ghavamipour, Ali Reza (University Medical Center Groningen); Turkmen, Fatih (University Medical Center Groningen); Wang, Rui (Student TU Delft); Liang, K. (TU Delft Cyber Security)","","2023","Synthetic data generation plays a crucial role in many areas where data is scarce and privacy/confidentiality is a significant concern. Generative Adversarial Networks (GANs), arguably one of the most widely used data synthesis techniques, allow for the training of a model (i.e., generator) that can generate real-looking data by playing a min-max game with a discriminator model. When multiple organizations are reluctant to share their sensitive data, GANs models can be trained in a federated manner, commonly with the use of differential privacy (DP). In order to achieve a reasonable level of model utility, DP trades privacy exhibiting vulnerability to various attacks (e.g., membership inference attack). In this paper, we propose a hybrid solution, PP-FedGAN, to the asynchronous federated, privacy-preserving training of GANs models by combining the CKKS homomorphic encryption (HE) scheme with differential privacy. The addition of HE results in around 10 seconds of overhead on the client side per round and 115 seconds on the entire training procedure. We also analyze the security of PP-FedGAN under the honest-but-curious security model. Where stronger security guarantees are required, our proposal presents a better alternative to solutions that only employ DP.","differential privacy; federated learning; gan; homomorphic encryption; synthetic data","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Cyber Security","","",""
"uuid:835f1e55-6dcb-4e0c-8223-aefe1d26d368","http://resolver.tudelft.nl/uuid:835f1e55-6dcb-4e0c-8223-aefe1d26d368","Sensing and Machine Learning for Automotive Perception: A Review","Pandharipande, Ashish (NXP Semiconductors); Cheng, Chih Hong (Fraunhofer Iks); Dauwels, J.H.G. (TU Delft Signal Processing Systems); Gurbuz, Sevgi Z. (University of South Alabama); Ibanez-Guzman, Javier (Group Renault); Li, Guofa (Chongqing University); Piazzoni, Andrea (Nanyang Technological University); Wang, Pu (Mitsubishi Electric Research Laboratories); Santra, Avik (Infineon Technologies, North America)","","2023","Automotive perception involves understanding the external driving environment and the internal state of the vehicle cabin and occupants using sensor data. It is critical to achieving high levels of safety and autonomy in driving. This article provides an overview of different sensor modalities, such as cameras, radars, and light detection and ranging (LiDAR) used commonly for perception, along with the associated data processing techniques. Critical aspects of perception are considered, such as architectures for processing data from single or multiple sensor modalities, sensor data processing algorithms and the role of machine learning techniques, methodologies for validating the performance of perception systems, and safety. The technical challenges for each aspect are analyzed, emphasizing machine learning approaches, given their potential impact on improving perception. Finally, future research opportunities in automotive perception for their wider deployment are outlined.","Advanced driver assistance system (ADAS); automotive perception; autonomous driving; cameras; light detection and ranging (LiDAR); radars; safety; sensor data processing","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-25","","","Signal Processing Systems","","",""
"uuid:035e67c4-1443-47de-a0b3-92ced2c86143","http://resolver.tudelft.nl/uuid:035e67c4-1443-47de-a0b3-92ced2c86143","The mental health of rural older adults: the role of the built environment in Jintang County","Liang, Ping (Chengdu University of Technology); Wang, Yan (Sichuan College of Architectural Technology); Wang, T. (TU Delft Design & Construction Management)","","2023","The mental health of older adults has become one of the major health challenges facing society today, which has attracted wide concerns from scholars in urban areas, but research in rural areas has been neglected. Therefore, this paper took rural older adult residents of 11 sample villages in Jintang County, Chengdu City, Sichuan Province, as the research object. After controlling the demographic characteristics of older adults in rural areas, this paper attempted to explore the effects of the rural built Environment on the mental health of older adults. Through field investigation in the sample villages, 515 valid questionnaires were obtained. The results from the Binary Logistic Regression Model show that good marital status, physical health, education level, well-constructed roads, and safe neighborhoods had significant positive effects on the mental health of rural older adults. Rural older adults who prefer to walk, cycle, and use public transport have better mental health, and accessibility to the periodic market, health station, bus station, village committee, supermarket, and the main road is positively correlated with the mental health of rural older adults, while the distance from home to the town center and coach terminal has a significant negative impact on the mental health of rural older adults. The research results provide a theoretical reference for further construction of rural aging environments.","mental health; older adults; binary logistic model; rural areas; built","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:50701b57-2ab6-4efb-ad5f-4a1b4f7c6d99","http://resolver.tudelft.nl/uuid:50701b57-2ab6-4efb-ad5f-4a1b4f7c6d99","Robustness analysis of CTV and OAR dose in clinical PBS-PT of neuro-oncological tumors: prescription-dose calibration and inter-patient variation with the Dutch proton robustness evaluation protocol","Rojo-Santiago, Jesús (Erasmus MC; Holland Particle Therapy Centre); Habraken, S.J.M. (Erasmus MC; Holland Particle Therapy Centre); Romero, Alejandra Méndez (Erasmus MC; Holland Particle Therapy Centre); Lathouwers, D. (TU Delft RST/Reactor Physics and Nuclear Materials); Wang, Yibing (Holland Particle Therapy Centre); Perko, Z. (TU Delft RST/Reactor Physics and Nuclear Materials); Hoogeman, M.S. (Erasmus MC; Holland Particle Therapy Centre)","","2023","Objective. The Dutch proton robustness evaluation protocol prescribes the dose of the clinical target volume (CTV) to the voxel-wise minimum (VWmin) dose of 28 scenarios. This results in a consistent but conservative near-minimum CTV dose (D98%,CTV). In this study, we analyzed (i) the correlation between VWmin/voxel-wise maximum (VWmax) metrics and actually delivered dose to the CTV and organs at risk (OARs) under the impact of treatment errors, and (ii) the performance of the protocol before and after its calibration with adequate prescription-dose levels.Approach. Twenty-one neuro-oncological patients were included. Polynomial chaos expansion was applied to perform a probabilistic robustness evaluation using 100,000 complete fractionated treatments per patient. Patient-specific scenario distributions of clinically relevant dosimetric parameters for the CTV and OARs were determined and compared to clinical VWmin and VWmax dose metrics for different scenario subsets used in the robustness evaluation protocol.Main results. The inclusion of more geometrical scenarios leads to a significant increase of the conservativism of the protocol in terms of clinical VWmin and VWmax values for the CTV and OARs. The protocol could be calibrated using VWmin dose evaluation levels of 93.0%-92.3%, depending on the scenario subset selected. Despite this calibration of the protocol, robustness recipes for proton therapy showed remaining differences and an increased sensitivity to geometrical random errors compared to photon-based margin recipes.Significance. The Dutch proton robustness evaluation protocol, combined with the photon-based margin recipe, could be calibrated with a VWmin evaluation dose level of 92.5%. However, it shows limitations in predicting robustness in dose, especially for the near-maximum dose metrics to OARs. Consistent robustness recipes could improve proton treatment planning to calibrate residual differences from photon-based assumptions.","geometrical and range errors; intensity modulated proton therapy; neuro-oncological tumors; polynomial chaos expansion; robust treatment planning; robustness evaluation","en","journal article","","","","","","","","","","","RST/Reactor Physics and Nuclear Materials","","",""
"uuid:081b2873-b53f-4513-8b4c-be1217875dd4","http://resolver.tudelft.nl/uuid:081b2873-b53f-4513-8b4c-be1217875dd4","Large-scale morphological changes and sediment budget of the Western Scheldt estuary 1955–2020: the impact of large-scale sediment management","Elias, Edwin P.L. (Deltares); van der Spek, A.J.F. (Deltares; Universiteit Utrecht); Wang, Zhengbing (TU Delft Coastal Engineering); Cleveringa, Jelmer (ARCADIS Nederland; Universiteit Utrecht); Jeuken, Claire J. L. (Deltares); Taal, Marcel (Deltares); van der Werf, Jebbe (University of Twente; Deltares)","","2023","In the Western Scheldt estuary, like in many estuaries, safe navigation, flood protection, and ecological targets require a balanced and sustainable sediment management. A thorough understanding of the morphodynamic functioning of the estuary and its response to changes in hydrodynamics (natural sediment transport) and large-scale interventions is imperative. This paper presents a detailed overview of over 65 years of morphological changes and a comprehensive sediment budget of the Western Scheldt estuary that is based on analysis of a unique series of frequent bathymetric surveys and historical data on human–sediment interactions of dredging, dredge disposal and sand mining. Solving the sediment budget reveals an annual sediment import of 2.2 million m3. The highest sediment imports occurred between 1980–1994 and 2005–2020 (2.9 and 3.7 million m3/year). A 1.3 million m3/year net export prevailed between 1994 and 2005. Natural variations in the hydrodynamics (e.g., tidal asymmetry and amplification) and sediment transports cannot explain the derived temporal variations in sediment import rates. Anthropogenic activities play a dominant role. Capital dredging of the main navigation channel has led to channel deepening and significantly increased dredge and disposal volumes. Disposal on tidal flats and in the secondary channel leads to a long-term storage of sand and, consequently, a local increase in bed level and a sand deficit in the remainder of the system that results in increased sediment imports. Large-scale disposal in the western part of the estuary can (temporarily) reverse the sediment exchange between the estuary and its mouth area, as observed between 1994 and 2005. Apparently, large-scale anthropogenic reallocation of sediment by dredging and/or disposal as part of navigation channel improvement, sand mining or nourishment essentially influences the morphological development of the Western Scheldt estuary. This reveals responsibilities as well as opportunities of sediment management for the Western Scheldt and similar estuaries worldwide.","Western Scheldt; sediment budget; coastal morphodynamics; impact of large-scale engineering","en","review","","","","","","","","","","","Coastal Engineering","","",""
"uuid:ce904b00-3c4d-4ddc-8857-361a078d1956","http://resolver.tudelft.nl/uuid:ce904b00-3c4d-4ddc-8857-361a078d1956","Modeling and Analysis of SRAM PUF Bias Patterns in 14nm and 7nm FinFET Technology Nodes","Masoumian, S. (TU Delft Computer Engineering; Intrinsic ID B.V.); Maes, Roel (Intrinsic ID B.V.); Wang, Rui (Intrinsic ID B.V.); Yerriswamy, Karthik Keni (Intrinsic ID B.V.); Schrijen, Geert-Jan (Intrinsic ID B.V.); Hamdioui, S. (TU Delft Computer Engineering); Taouil, M. (TU Delft Computer Engineering)","","2023","SRAM Physical Unclonable Functions (PUFs) are one of the popular forms of PUFs that can be used to generate unique identifiers and randomness for security purposes. Hence, their resilience to attacks is crucial. The probability of attacks increases when the SRAM PUF start-up values follow a predictable pattern which we refer to as bias. In this paper, we investigate the parameters impacting the SRAM PUF bias of advanced FinFET SRAM designs. In particular, we analyze the bias with respect to temperature, mismatches in the power supply network, and ramp-up time. We also consider process variation, circuit noise, and SRAM layout in our analysis. Our simulations results match with the silicon measurements. From the experiments we conclude that (i) the SRAM layout and in particular the power supply network can lead to a bias, (ii) this bias increases with temperature, and (iii) this bias increases when the supply ramp-up time decreases.","Bias; FinFET; Power Supply Network; SRAM PUF; Temperature","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-22","","","Computer Engineering","","",""
"uuid:9aa45ff6-8de0-455f-903b-2ced8af5857d","http://resolver.tudelft.nl/uuid:9aa45ff6-8de0-455f-903b-2ced8af5857d","Bicycle Data-Driven Application Framework: A Dutch Case Study on Machine Learning-Based Bicycle Delay Estimation at Signalized Intersections Using Nationwide Sparse GPS Data","Yuan, Y. (TU Delft Transport and Planning); Wang, Kaiyi (Universiteit van Amsterdam); Duives, D.C. (TU Delft Transport and Planning); Hoogendoorn, S.P. (TU Delft Transport and Planning); Hoogendoorn-Lanser, S. (TU Delft Corporate Innovations); Lindeman, Rick (Rijkswaterstaat)","","2023","Data-driven approaches are helpful for quantitative justification and performance evaluation. The Netherlands has made notable strides in establishing a national protocol for bicycle traffic counting and collecting GPS cycling data through initiatives such as the Talking Bikes program. This article addresses the need for a generic framework to harness cycling data and extract relevant insights. Specifically, it focuses on the application of estimating average bicycle delays at signalized intersections, as this is an essential variable in assessing the performance of the transportation system. This study evaluates machine learning (ML)-based approaches using GPS cycling data. The dataset provides comprehensive yet incomplete information regarding one million bicycle rides annually across The Netherlands. These ML models, including random forest, k-nearest neighbor, support vector regression, extreme gradient boosting, and neural networks, are developed to estimate bicycle delays. The study demonstrates the feasibility of estimating bicycle delays using sparse GPS cycling data combined with publicly accessible information, such as weather information and intersection complexity, leveraging the burden of understanding local traffic conditions. It emphasizes the potential of data-driven approaches to inform traffic management, bicycle policy, and infrastructure development.","data-driven bicycle applications; GPS cycling data; machine learning; bicycle delays; signalized intersections","en","journal article","","","","","","","","","","Transport and Planning","Transport and Planning","","",""
"uuid:caadb01b-a462-43c6-9967-be872cf30cb3","http://resolver.tudelft.nl/uuid:caadb01b-a462-43c6-9967-be872cf30cb3","Rural Infrastructure Lifecycle Inclusiveness Impact Path Analysis: Combining Logical Framework and Structural Equation Modeling","Jiang, Aichun (Chengdu University of Information Technology); Ao, Yibin (Chengdu University of Technology); Yang, Ruo (Chengdu University of Information Technology); Wang, T. (TU Delft Design & Construction Management)","","2023","The rural infrastructures require inclusiveness in the whole lifecycle (WLC) for the benefits of the society. The theory of inclusive growth has been widely studied since its introduction in the infrastructure system research. However, the majority of the related studies has focused on macro level measurements and no systematic research has been carried out on the microlevel for inclusiveness formation and impact path discovery so that detailed recommendations regarding the process can be formulated. The WLC of infrastructure is a dynamic process, reflected in different stages with various activities and multiple factor groups that connect and influence each other. To address and analyze this dynamic and interdependent process from a micro perspective, this study applies the logical framework method in constructing nine impact paths of rural infrastructure inclusiveness for the WLC, which revealed the influence mechanism of rural infrastructure inclusiveness at the microlevel. According to the results, ""project quality""has the most significant influence on the rural infrastructure inclusiveness.","","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:0d0917bf-f446-46b3-9a35-d537fbe15e60","http://resolver.tudelft.nl/uuid:0d0917bf-f446-46b3-9a35-d537fbe15e60","Impact of Junction Length on Supercurrent Resilience against Magnetic Field in InSb-Al Nanowire Josephson Junctions","Levajac, V. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Mazur, G.P. (TU Delft QRD/Wimmer Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); van Loo, N. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Borsoi, F. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Badawy, Ghada (Eindhoven University of Technology); Gazibegovic, Sasa (Eindhoven University of Technology); Bakkers, Erik P.A.M. (Eindhoven University of Technology); Heedt, S. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, J. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)","","2023","Semiconducting nanowire Josephson junctions represent an attractive platform to investigate the anomalous Josephson effect and detect topological superconductivity. However, an external magnetic field generally suppresses the supercurrent through hybrid nanowire junctions and significantly limits the field range in which the supercurrent phenomena can be studied. In this work, we investigate the impact of the length of InSb-Al nanowire Josephson junctions on the supercurrent resilience against magnetic fields. We find that the critical parallel field of the supercurrent can be considerably enhanced by reducing the junction length. Particularly, in 30 nm long junctions supercurrent can persist up to 1.3 T parallel field─approaching the critical field of the superconducting film. Furthermore, we embed such short junctions into a superconducting loop and obtain the supercurrent interference at a parallel field of 1 T. Our findings are highly relevant for multiple experiments on hybrid nanowires requiring a magnetic-field-resilient supercurrent.","","en","journal article","","","","","","","","","","","QRD/Kouwenhoven Lab","","",""
"uuid:d5b1685d-9a33-4717-9cde-0eab175873aa","http://resolver.tudelft.nl/uuid:d5b1685d-9a33-4717-9cde-0eab175873aa","Crystallization Process for High-Quality Cs0.15FA0.85PbI2.85Br0.15Film Deposited via Simplified Sequential Vacuum Evaporation","Yan, J. (TU Delft Photovoltaic Materials and Devices); Zhao, J. (TU Delft ChemE/Opto-electronic Materials); Wang, H. (TU Delft Photovoltaic Materials and Devices); Kerklaan, Mels (Student TU Delft); Bannenberg, L.J. (TU Delft RID/TS/Instrumenten groep); Ibrahim, B. (TU Delft ChemE/O&O groep); Savenije, T.J. (TU Delft ChemE/Opto-electronic Materials); Mazzarella, L. (TU Delft Photovoltaic Materials and Devices); Isabella, O. (TU Delft Photovoltaic Materials and Devices)","","2023","Multiple-source thermal evaporation is emerging as an excellent technique to obtain perovskite (PVK) materials for solar cell applications due to its solvent-free processing, accurate control of stoichiometric ratio, and potential for scalability. Nevertheless, the currently reported layer-by-layer deposition approach is afflicted by long processing times caused by the multiple repetitions of thin films, which hinder industrial uptake. On the other hand, the coevaporation entails higher complexity due to the challenges of controlling the sublimation of multiple sources simultaneously. In this work, we propose a simplified approach consisting of a single-cycle deposition (SCD) of three thick precursor layers to obtain high-quality Cs0.15FA0.85PbI2.85Br0.15 (CsFAPbIBr) films. After annealing, the optimized PVK film exhibits comparable properties to the one deposited by multicycle deposition in terms of crystal structure, in-depth uniformity, and optoelectrical properties. Also, the formation and evolution of SCD PVK during annealing are investigated. We found that, in the competitive processes of precursor diffusion and reaction, the presence of cesium bromide can assist precursor mixing driven by the annealing treatment, demonstrating a reaction-limited process in the PVK conversion. With this simplified SCD approach, a PVK film is obtained with expected optical and opto-electronic properties, providing an appealing way for future thermally evaporated PVK device preparation.","CsFAPbIBr; postdeposition annealing; sequential vacuum evaporation; single-cycle deposition; thermal evaporation","en","review","","","","","","","","","","","Photovoltaic Materials and Devices","","",""
"uuid:66cbed5e-17ad-4309-873f-67f19ccda7e2","http://resolver.tudelft.nl/uuid:66cbed5e-17ad-4309-873f-67f19ccda7e2","Incremental Nonlinear Control for Aeroelastic Wing Load Alleviation and Flutter Suppression","Schildkamp, R.R.M. (TU Delft Aerospace Structures & Computational Mechanics); Chang, J. (TU Delft Aerospace Structures & Computational Mechanics); Sodja, J. (TU Delft Aerospace Structures & Computational Mechanics); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics)","","2023","This paper proposes an incremental nonlinear control method for an aeroelastic system’s gust load alleviation and active flutter suppression. These two control objectives can be achieved without modifying the control architecture or the control parameters. The proposed method has guaranteed stability in the Lyapunov sense and also has robustness against external disturbances and model mismatches. The effectiveness of this control method is validated by wind tunnel tests of an active aeroelastic parametric wing apparatus, which is a typical wing section containing heave, pitch, flap, and spoiler degrees of freedom. Wind tunnel experiment results show that the proposed nonlinear incremental control can reduce the maximum gust loads by up to 46.7% and the root mean square of gust loads by up to 72.9%, while expanding the flutter margin by up to 15.9%.","aeroservoelasticity; wind tunnel experiment; gust load alleviation; flutter suppression; nonlinear incremental control","en","journal article","","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:e8b0d8a2-4c7e-42d4-9226-d33aaacbcc4e","http://resolver.tudelft.nl/uuid:e8b0d8a2-4c7e-42d4-9226-d33aaacbcc4e","Greedy Sensor Selection: Leveraging Submodularity Based on Volume Ratio of Information Ellipsoid","Liu, Lingya (East China Normal University); Hua, Cunqing (Shanghai Jiao Tong University); Xu, Jing (East China Normal University); Leus, G.J.T. (TU Delft Signal Processing Systems); Wang, Yiyin (Shanghai Jiao Tong University)","","2023","This article focuses on greedy approaches to select the most informative k sensors from N candidates to maximize the Fisher information, i.e., the determinant of the Fisher information matrix (FIM), which indicates the volume of the information ellipsoid (VIE) constructed by the FIM. However, it is a critical issue for conventional greedy approaches to quantify the Fisher information properly when the FIM of the selected subset is rank-deficient in the first (n-1) steps, where n is the problem dimension. In this work, we propose a new metric, i.e., the Fisher information intensity (FII), to quantify the Fisher information contained in the subset S with respect to that in the ground set N specifically in the subspace spanned by the vectors associated with S. Based on the FII, we propose to optimize the ratio between VIEs corresponding to S and N. This volume ratio is composed of a nonzero (i.e., the FII) and a zero part. Moreover, the volume ratio can be easily calculated based on a change of basis. A cost function is developed based on the volume ratio and proven monotone submodular. A greedy algorithm and its fast version are proposed accordingly to guarantee a near-optimal solution with a complexity of O Nkn-3 and O Nkn2, respectively. Numerical results demonstrate the superiority of the proposed algorithms under various measurement settings.","Greedy sensor selection; Fisher information intensity; change of basis; volume ratio; submodularity","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-12-21","","","Signal Processing Systems","","",""
"uuid:9721197d-bb95-4784-930c-2531821e1b86","http://resolver.tudelft.nl/uuid:9721197d-bb95-4784-930c-2531821e1b86","Laser shape variation influence on melt pool dynamics and solidification microstructure in laser powder bed fusion","Li, Erlei (University of Queensland); Shen, Haopeng (CSIRO Manufacturing, Victoria); Wang, L. (TU Delft QN/Akhmerov Group); Wang, Geoff (University of Queensland); Zhou, Zongyan (Monash University; Jiangxi University of Science and Technology)","","2023","The shape variation of the laser beam is evidently observed in the laser powder bed fusion (LPBF) process because of changes in laser incidence angle and misalignment between the build plate and the laser focus plane. This issue is particularly relevant in large-scale LPBF systems where the laser beam needs to scan a large build area. However, most LPBF modeling studies assume vertical laser radiation. The heat transfer, melt pool, and solidification evolution due to the laser shape variation have not been well addressed and quantified. In the present study, the temperature distribution, melt pool geometry and flow dynamics are captured via numerical modelling, and the grain morphology is characterized under various laser incidence angles. The results show that the melt pool depth becomes shallower, and the width is near the beam size as the laser beam becomes more elongated. The beam shape variation can affect the liquid flow pattern with increasing incidence angle, resulting in a larger vortex at the front of the melt pool and a smaller vortex at the rear of the melt pool. The thermal gradient increases and the solidification rate decreases as the laser incident angle becomes larger. The present study enhances the understanding of multi-physics in the LPBF process.","Laser incidence angle; Laser powder bed fusion; Laser shape variation; Melt pool dynamics; Solidification microstructure","en","journal article","","","","","","","","","","","QN/Akhmerov Group","","",""
"uuid:6fab90fe-c63b-4628-b435-9e634a4ffa62","http://resolver.tudelft.nl/uuid:6fab90fe-c63b-4628-b435-9e634a4ffa62","Reverse Recovery Optimization of Multiepi Superjunction MOSFET Based on Tunable Doping Profile","Liu, Ke (Southern University of Science and Technology); Tan, C. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology); Li, Shizhen (Southern University of Science and Technology); Yuan, Wucheng (Southern University of Science and Technology); Liu, X. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); French, P.J. (TU Delft Bio-Electronics); Ye, H. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology); Wang, S. (TU Delft Bio-Electronics; Southern University of Science and Technology)","","2023","This paper proposes and simulates research on the reverse recovery characteristics of two novel superjunction (SJ) MOSFETs by adjusting the doping profile. In the manufacturing process of the SJ MOSFET using multilayer epitaxial deposition (MED), the position and concentration of each Boron bubble can be adjusted by designing different doping profiles to adjust the resistance of the upper half P-pillar. A higher P-pillar resistance can slow down the sweep out speed of hole carriers when the body diode is turned off, thus resulting in a smoother reverse recovery current and reducing the current recovery rate (d (Formula presented.) /d (Formula presented.)) from a peak to zero. The simulation results show that the reverse recovery peak current (I (Formula presented.)) of the two proposed devices decreased by 5% and 3%, respectively, compared to the conventional SJ. Additionally, the softness factor (S) increased by 64% and 55%, respectively. Furthermore, this study also demonstrates a trade-off relationship between static and reverse recovery characteristics with the adjustable doping profile, thus providing a guideline for actual application scenarios.","superjunction; MOSFET; doping profile; reverse recovery; body diode","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:9aa427d9-f634-46ef-bab8-186dac3af2d7","http://resolver.tudelft.nl/uuid:9aa427d9-f634-46ef-bab8-186dac3af2d7","Anisotropic proximity-induced superconductivity and edge supercurrent in Kagome metal, K1-xV3Sb5","Wang, Y. (TU Delft QN/Ali Lab; Max Planck Institute of Microstructure Physics; Kavli institute of nanoscience Delft); Yang, Shuo Ying (Max Planck Institute of Microstructure Physics); Sivakumar, Pranava K. (Max Planck Institute of Microstructure Physics); Ortiz, Brenden R. (University of California); Teicher, Samuel M.L. (University of California); Wu, H. (TU Delft QN/Ali Lab; Max Planck Institute of Microstructure Physics; Kavli institute of nanoscience Delft); Srivastava, Abhay K. (Max Planck Institute of Microstructure Physics); Garg, Chirag (Max Planck Institute of Microstructure Physics; IBM Almaden Research Center); Ali, M.N. (TU Delft QN/Ali Lab; Max Planck Institute of Microstructure Physics; Kavli institute of nanoscience Delft)","","2023","Materials with Kagome nets are of particular importance for their potential combination of strong correlation, exotic magnetism, and electronic topology. KV3Sb5 was discovered to be a layered topological metal with a Kagome net of vanadium. Here, we fabricated Josephson Junctions of K1-xV3Sb5 and induced superconductivity over long junction lengths. Through magnetoresistance and current versus phase measurements, we observed a magnetic field sweeping direction-dependent magnetoresistance and an anisotropic interference pattern with a Fraunhofer pattern for in-plane magnetic field but a suppression of critical current for out-of-plane magnetic field. These results indicate an anisotropic internal magnetic field in K1-xV3Sb5 that influences the superconducting coupling in the junction, possibly giving rise to spin-triplet superconductivity. In addition, the observation of long-lived fast oscillations shows evidence of spatially localized conducting channels arising from edge states. These observations pave the way for studying unconventional superconductivity and Josephson device based on Kagome metals with electron correlation and topology.","","en","journal article","","","","","","","","","","","QN/Ali Lab","","",""
"uuid:1f2ad684-f792-456d-958e-f159f32c9073","http://resolver.tudelft.nl/uuid:1f2ad684-f792-456d-958e-f159f32c9073","Effects of downstream environmental flow release on enhancing the groundwater recharge and restoring the groundwater/surface-water connectivity in Yongding River, Beijing, China","Liu, S. (TU Delft Water Resources; IHE Delft Institute for Water Education); Zhou, Yangxiao (IHE Delft Institute for Water Education; Hebei University of Geosciences); Zang, Yining (IHE Delft Institute for Water Education); McClain, M.E. (TU Delft Water Resources; IHE Delft Institute for Water Education); Wang, Xu sheng (China University of Geosciences)","","2023","The Yongding River (Beijing, China) was dry most times of the year, and groundwater storage was severely depleted. To address this issue, a river rehabilitation project was initiated. A downstream environmental flow release (EFR) project from upstream reservoirs has been implemented since 2019. This study evaluated the impact of EFR by constructing transient groundwater-flow and numerical tracer transport models to simulate the hydrogeological responses to the water release events in 2019–2020. The study identified two factors that significantly influence the river leakage rate, which are operational factors (i.e., water release rate and duration) and physical factors (i.e., hydraulic properties of the riverbed, regional hydraulic gradients, and groundwater depth) that determine the maximum water availability for groundwater recharge and maximum infiltration capacity, respectively. Predictive modelling was performed to assess the long-term effects of the proposed EFR scheme from 2021 to 2050, which showed that groundwater levels along the river will increase by 10–20 m by 2050. Groundwater storage is expected to be largely recovered and groundwater/surface-water connectivity in the middle reach of the river will be restored. This restoration will not only maintain the environmental flow for the benefit of ecosystems but also enhance groundwater recharge, promoting sustainable groundwater development in the region. Overall, this study provides valuable insights into the effectiveness of the proposed EFR scheme in achieving sustainable groundwater development in the region.","China; Environmental flow release; Groundwater recharge; Groundwater/surface-water relations; Numerical simulations","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:b25e77b6-5ad2-48f3-a11d-d152b829c286","http://resolver.tudelft.nl/uuid:b25e77b6-5ad2-48f3-a11d-d152b829c286","Performance Comparison between Data Centers with Different Airflow Management Technologies","Li, Xueqiang (Tianjin University of Commerce); Zhang, Zhongyao (Tianjin University of Commerce); Wang, Qihui (Tianjin University of Commerce); Yang, Xiaohu (Xi’an Jiaotong University); Hooman, K. (TU Delft Process and Energy); Liu, Shengchun (Tianjin University; Tianjin University of Commerce)","","2023","Air cooling systems are widely used in current data centers owing to their low capital costs and high reliability. To satisfy the increasing rack power density, the optimal air-cooling technology and an economic analysis should be carefully discussed. Therefore, this study discusses four airflow management technologies: Case 1: raised floor and cold aisle containment supply/computer room air conditioning (CRAC) direct return; Case 2: CRAC direct supply/hot aisle containment (HAC) return; Case 3: overhead duct supply/CRAC direct return; and Case 4: overhead duct supply/HAC return. Using a validated model, the thermal and economic performances of each case were compared. Results showed that Case 4 exhibited the best thermal performance, followed by Cases 3, 2, and 1. Case 1 cannot satisfy the heat dissipation requirement when the rack power density is larger than 12.5 kW; whereas only Case 4 can be used when the power density is larger than 15 kW. Regarding location within China, owing to the high ambient temperature, Shenzhen showed the highest annual cost value and power usage effectiveness, followed by Shanghai, Xi’an, Beijing, and Harbin. Finally, Cases 3 and 4 are recommended for application when the rack power density is greater than 10 kW.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-15","","Process and Energy","","","",""
"uuid:4f5b8700-bab7-45c2-8875-f63de17073b5","http://resolver.tudelft.nl/uuid:4f5b8700-bab7-45c2-8875-f63de17073b5","Flow Ripple Reduction in Reciprocating Pumps by Multi-Phase Rectification","Özkayar, G. (TU Delft Micro and Nano Engineering); Wang, Z. (TU Delft Micro and Nano Engineering); Lötters, J.C. (TU Delft Precision and Microsystems Engineering; Bronkhorst High-Tech BV); Tichem, M. (TU Delft Micro and Nano Engineering); Ghatkesar, M.K. (TU Delft Micro and Nano Engineering)","","2023","Reciprocating piezoelectric micropumps enable miniaturization in microfluidics for lab-on-a-chip applications such as organs-on-chips (OoC). However, achieving a steady flow when using these micropumps is a significant challenge because of flow ripples in the displaced liquid, especially at low frequencies or low flow rates (<50 µL/min). Although dampers are widely used for reducing ripples in a flow, their efficiency depends on the driving frequency of the pump. Here, we investigated multi-phase rectification as an approach to minimize ripples at low flow rates by connecting piezoelectric micropumps in parallel. The efficiency in ripple reduction was evaluated with an increasing number (n) of pumps connected in parallel, each actuated by an alternating voltage waveform with a phase difference of 2π/n (called multi-phase rectification) at a chosen frequency. We introduce a fluidic ripple factor ((Formula presented.)), which is the ratio of the root mean square ((Formula presented.)) value of the fluctuations present in the rectified output to the average fluctuation-free value of the discharge flow, as a metric to express the quality of the flow. The fluidic ripple factor was reduced by more than 90% by using three-phase rectification when compared to one-phase rectification in the 2–60 μL/min flow rate range. Analytical equations to estimate the fluidic ripple factor for a chosen number of pumps connected in parallel are presented, and we experimentally confirmed up to four pumps. The analysis shown can be used to design a frequency-independent multi-phase fluid rectifier to the desired ripple level in a flow for reciprocating pumps.","micropump; reciprocating pump; flow ripple; fluidic rectification; multi-phase rectifier","en","journal article","","","","","","","","","","Precision and Microsystems Engineering","Micro and Nano Engineering","","",""
"uuid:afcc74cd-ab52-403b-af02-c6315dcefed4","http://resolver.tudelft.nl/uuid:afcc74cd-ab52-403b-af02-c6315dcefed4","Sustainable Assessment Tools for Higher Education Institutions: Developing Two-Hierarchy Tools for China","Du, Yawei Du (Chinese Academy of Sciences); Ye, Qing (Hebei University of Technology); Liu, Hongjiang (Tianjin University); Wu, Yuting (Tianjin University); Wang, F. (TU Delft Network Architectures and Services)","","2023","Higher Education Institutions (HEIs) play an increasingly significant role in the practice of sustainability. For HEIs in their early stages of sustainability, they are still in need of sustainable assessment tools (SATs) that are suitable for their local context and also lead international sustainable development. The purpose of this paper is to develop a two-hierarchy sustainability assessment tool (THSus) for Chinese higher education institutions, including a quick analysis tool (QAT) and an in-depth benchmarking tool (IBT). The QAT provided a general overview of campus sustainability for HEIs to initiate initial actions and screen cases for the IBT. The IBT then provides more targeted analysis to plan long-term strategic changes. Based on the analysis of HEI cases, a 34-person Chinese research team was enlisted to discuss and select characteristics to formulate THSus. Indicators and weightings were developed according to the tool’s purpose and applied to 15 cases to test its effectiveness. Results showed that THSus is suitable for systematically analyzing campus issues, particularly in research areas. It offers a regional solution for Chinese campuses that is adaptable and considers the comprehensive core of sustainability.","campus sustainability; green campuses; higher education institution; sustainable assessment tools; two-hierarchy tools","en","journal article","","","","","","","","","","","Network Architectures and Services","","",""
"uuid:ddbb29f4-a052-49f1-8e44-f7d0c5252ea8","http://resolver.tudelft.nl/uuid:ddbb29f4-a052-49f1-8e44-f7d0c5252ea8","DipSAR: Deep Image Prior for Sparse Sampled Near-Field SAR Millimeter-Wave Imaging","Assabumrungrat, Rawin (Tohoku University); Kumchaiseemak, N. (TU Delft Microwave Sensing, Signals & Systems; Vidyasirimedhi Institute of Science and Technology); Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Wang, D. (TU Delft Microwave Sensing, Signals & Systems); Punpeng, Phoom (Ruamrudee International School); Fioranelli, F. (TU Delft Microwave Sensing, Signals & Systems); Wilaiprasitporn, Theerawit (Vidyasirimedhi Institute of Science and Technology)","","2023","We present a deep learning-based approach called DipSAR for reconstructing millimeter-wave synthetic aperture radar (SAR) images from sparse samples. The primary challenge lies in the requirement of a large training dataset for deep learning schemes. To overcome this issue, we employ the deep image prior (DIP) technique, which eliminates the need for a large dataset and instead utilizes only the sparse sample itself. Our proposed DipSAR model recovers missing samples from sparse data and reconstructs the SAR image using a conventional method. In this study, we utilize an existing SAR dataset and create fourteen different patterns to generate additional sparse samples by removing certain data points. We then evaluate the performance of DipSAR in comparison to the conventional method. The results show that DipSAR outperforms the conventional method in terms of the intersection over union (IoU) score.","deep image prior; millimeter-wave; near-field imaging; sparse data; synthetic aperture radar","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-06","","","Microwave Sensing, Signals & Systems","","",""
"uuid:8c79e3ea-7b18-433f-9e3d-d392e7b5373a","http://resolver.tudelft.nl/uuid:8c79e3ea-7b18-433f-9e3d-d392e7b5373a","Effects of micro-bubble aeration on the pollutant removal and energy-efficient process in a floc-granule sludge coexistence system","Liu, Minghui (Zhengzhou University); Wang, Ju (Zhengzhou University); Peng, Z. (TU Delft Sanitary Engineering; Zhengzhou University)","","2023","To investigate energy-saving approaches in wastewater treatment plants and decrease aeration energy consumption, this study successfully established a floc-granule coexistence system in a sequencing batch airlift reactor (SBAR) employing micro-bubble aeration. The analysis focused on granule formation and pollutant removal under various aeration intensities, and compared its performance with a traditional floc-based coarse-bubble aeration system. The results showed that granulation efficiency was positively associated with aeration intensity, which enhanced the secretion of extracellular polymeric substances (EPSs) and facilitated granule formation. The SBAR with the micro-aeration intensity of 30 mL·min-1 showed the best granulation performance (granulation efficiency 52.6%). In contrast to the floc-based system, the floc-granule coexistence system showed better treatment performance, and the best removal efficiencies of NH4+-N, TN, and TP were 100.0, 77.0, and 89.5%, respectively. The floc-granule coexistence system also enriched higher abundance of nutrients removal microbial species, such as Nitrosomonas (0.05-0.14%), Nitrospira (0.14-2.32%), Azoarcus (2.95-12.17%), Thauera (0.43-1.95%), and Paracoccus (0.76-2.89%). The energy-saving potential was evaluated, which indicated it is feasible for the micro-aeration floc-granule coexistence system to decrease the aeration consumption by 14.4% as well as improve the effluent.","energy saving; granular sludge; micro-bubble; sequencing batch airlift reactor","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:822e124b-702f-4773-b760-d8ed7432d182","http://resolver.tudelft.nl/uuid:822e124b-702f-4773-b760-d8ed7432d182","Effect of Gas Composition on Surfactant Injectivity in a Surfactant-Alternating-Gas Foam Process","Gong, J. (TU Delft Reservoir Engineering; Hohai University); Wang, Yuan (Hohai University); Tewari, Raj Deo (Petronas Research); Kamarul Bahrim, Ridhwan Zhafri B. (Petronas Research); Rossen, W.R. (TU Delft Atmospheric Remote Sensing)","","2023","Aqueous foam is a dispersion of gas in liquid, where the liquid acts as the continuous phase and the gas is separated by thin liquid films stabilized by a surfactant. Foam injection is a widely used technique in various applications, including CO2 sequestration, enhanced oil recovery, soil remediation, etc. Surfactant-alternating-gas (SAG) is a preferred approach for foam injection, and injectivity plays a vital role in determining the efficiency of the SAG process. Different gases can be applied depending on the process requirements and availability. However, the underlying mechanisms by which gas composition impacts injectivity are not yet fully understood. In this work, the effect of gas composition on fluid behavior and injectivity in a SAG process was investigated using three gases: N2, CO2, and Kr. Our observations revealed that gas solubility in liquid was key for the formation and evolution of liquid fingers, and therefore was very important for liquid injectivity. A lower gas solubility in liquid led to a slower increase in surfactant solution injectivity. In addition, the development of surfactant solution injectivity took significantly longer when the surfactant solution was partially pre-saturated compared to when it was unsaturated. Additionally, the propagation of the collapsed-foam bank during gas injection was accelerated when the gas had a greater solubility in water.","foam; surfactant-alternating-gas; injectivity; gas composition; solubility","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:d7be3bdc-bfaf-4ff1-b024-61d8c903c2ac","http://resolver.tudelft.nl/uuid:d7be3bdc-bfaf-4ff1-b024-61d8c903c2ac","Quantification and comparison of hierarchy in Public Transport Networks","Wang, Z. (TU Delft Transport and Planning); Huang, Ketong (Beijing Transport Institute; Student TU Delft); Massobrio, R.M. (TU Delft Transport and Planning; University of Cadiz); Bombelli, A. (TU Delft Air Transport & Operations); Cats, O. (TU Delft Transport and Planning)","","2023","Network hierarchy describes the relative arrangement of network elements and reflects its fundamental structure. We propose a multi-dimensional topology-based method for quantifying and comparing the extent to which different Public Transport Networks (PTNs) exhibit a hierarchical structure. The proposed method considers the uneven distribution of node importance with different definitions (e.g., degree centrality and betweenness centrality) in a PTN, the clustering of nodes and the node connection patterns. We apply the developed method on 63 high-capacity PTNs worldwide using General Transit Feed Specification (GTFS) data. In addition to global indicators, we use the goodness-of-fit between the probability density function of local indicators and a skew-normal distribution to quantify the extent of PTN hierarchy. Results show that the scale-free network structure and preferential attachment do not vary much across PTNs. In contrast, stop accessibility and traffic intermediacy vary considerably across PTNs as reflected by the closeness centrality and betweenness centrality distributions. Lastly, metro systems exhibit a more hierarchical structure than their tram and Bus Rapid Transit (BRT) counterparts. This work makes a first step towards a better mapping and comparison of different PTNs, which can assist academics and practitioners in better (re)designing and planning the PTNs of the future.","Public transport networks; Hierarchy; Network science; Topology; General Transit Feed Specification (GTFS)","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:e742494b-0e5b-4b40-899b-9546d491e636","http://resolver.tudelft.nl/uuid:e742494b-0e5b-4b40-899b-9546d491e636","Inter-Vector Interference Self-Cancellation Scheme for Differential OSDM in Underwater Acoustic Communications","Wang, Yujie (Northwestern Polytechnical University); Zhang, Qunfei (Northwestern Polytechnical University); Ma, Shengqian (Northwestern Polytechnical University); Zhang, Lingling (Northwestern Polytechnical University); Han, Jing (Northwestern Polytechnical University); Leus, G.J.T. (TU Delft Signal Processing Systems)","","2023","Differential orthogonal signal-division multiplexing (OSDM) is attractive for underwater acoustic (UWA) communications because it can eliminate channel estimation, resulting in a substantial reduction of complexity at the receiver. However, when the channel is time-varying, it may suffer from serious inter-vector interference (IVI), which is similar to inter-carrier interference (ICI) in differential orthogonal frequency-division multiplexing (OFDM). To mitigate this degradation of system performance, this paper provides a novel two-hop differential OSDM system based on IVI self-cancellation. Although this method improves system reliability at the cost of losing data rate, it is easy to implement in UWA modems. Finally, numerical simulations demonstrate the effectiveness of the proposed two-hop differential OSDM system over time-varying UWA channels.","Differential OSDM; IVI self-cancellation; timevarying channels; underwater acoustic communications","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-06","","","Signal Processing Systems","","",""
"uuid:9f144dfd-7168-4820-9736-c2c315feb33b","http://resolver.tudelft.nl/uuid:9f144dfd-7168-4820-9736-c2c315feb33b","LeakageScatter: Backscattering LiFi-leaked RF Signals","Mir, Muhammad Sarmad (Carlos III University of Madrid); Cui, Minhao (University of Massachusetts Amherst); Guzman, Borja Genoves (IMDEA Networks Institute); Wang, Q. (TU Delft Embedded Systems); Xiong, Jie (University of Massachusetts Amherst); Giustiniano, Domenico (IMDEA Networks Institute)","","2023","Radio-Frequency (RF) backscatter has emerged as a low-power communication technique. Backscatter systems either rely on active signal generators (spectrum efficient, but dedicated infrastructure) or existing ambient wireless transmissions (existing infrastructure, but spectrum inefficient). In this paper, we aim to make RF backscatter spectrum efficient and at the same time work with existing infrastructure. We propose to leverage the deployment of LiFi networks built upon LED bulbs for pervasive RF backscatter. We experimentally demonstrate that LiFi, which passively leaks RF signals, can be exploited as a radio carrier generator for low-power RF backscatter. We further design LeakageScatter, the first backscatter system operating in the ISM band and exploiting LiFi-leaked RF signals, without the need to actively generate the carrier wave. We customize the design of the loop at the LiFi transmitter, as well as the coil antennas at the tag and RF backscatter receiver, to optimize the system performance. We propose to opportunistically enable the oscillator of the backscatter tag in the software that could reduce the energy consumption on backscattering by up to 75%. Experimental results show that LeakageScatter achieves a backscattering distance up to 10 m and 18 m in indoor and outdoor scenarios, respectively, without using a dedicated RF carrier generator.","backscatter; implementation; leaked RF signals; LiFi; system design","en","conference paper","Association for Computing Machinery (ACM)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-22","","","Embedded Systems","","",""
"uuid:e530e4e5-8720-4d39-be12-c40466d374e0","http://resolver.tudelft.nl/uuid:e530e4e5-8720-4d39-be12-c40466d374e0","Workshop on Understanding and Mitigating Cognitive Biases in Human-AI Collaboration","Boonprakong, Nattapat (University of Melbourne); He, G. (TU Delft Web Information Systems); Gadiraju, Ujwal (TU Delft Web Information Systems); Van Berkel, Niels (Aalborg University); Wang, Danding (Chinese Academy of Sciences); Chen, Si (University of Illinois at Urbana-Champaign); Liu, Jiqun (University of Oklahoma); Tag, Benjamin (Monash University); Goncalves, Jorge (University of Melbourne); Dingler, Tilman (University of Melbourne)","Ames, Morgan (editor); Fussell, Susan (editor); Gilbert, Eric (editor); Liao, Vera (editor); Ma, Xiaojuan (editor); Page, Xinru (editor); Rouncefield, Mark (editor); Singh, Vivek (editor); Wisniewski, Pamela (editor)","2023","AI systems are increasingly incorporated into human decision-making. Yet, human decision-makers are often affected by their cognitive biases. In critical settings, such as medical diagnosis, criminal judgment, or information consumption, these cognitive biases hinder optimal decision outcomes, thereby resulting in dangerous decisions and negative societal impact. The use of AI systems can amplify and exacerbate cognitive biases in their users. In this workshop, we seek to foster discussions on ongoing research around cognitive biases in human-AI collaboration and identify future research directions to understand, quantify, and mitigate the effects of cognitive biases. We will explore cognitive biases appearing in various contexts of human-AI collaboration: what can cause them?; how can we measure, model, mitigate, and manage cognitive biases?; and how can we utilise cognitive biases for the greater good? We will reflect on workshop discussions to form a research community around cognitive biases and bias-aware systems.","Cognitive Bias; Debiasing; Human-AI Collaboration","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Web Information Systems","","",""
"uuid:e92c2dbe-2c98-4ab6-917e-d033c87b2035","http://resolver.tudelft.nl/uuid:e92c2dbe-2c98-4ab6-917e-d033c87b2035","Overcoming communication and information barriers in the dutch energy transition: A Study on Online Sources of Energy-Efficient Retrofits in Homeowners’ Associations","Bingöl, C.K. (TU Delft Design & Construction Management); Wang, T. (TU Delft Design & Construction Management); Ersoy, A. (TU Delft Urban Development Management); van Bueren, Ellen (TU Delft Management in the Built Environment)","Lopes, Marta (editor); Matschoss, Kaisa (editor); Bouman, Thijs (editor)","2023","This paper focuses on the information and communication challenges in the Dutch energy transition in the built environment, with a specific focus on energy-efficient retrofits (EER) in homeowners’ associations (HOAs). The research surveyed the literature on barriers and drivers related to information and communication in EERs. It systematically investigated the information sources and communication channels provided by governmental and non-governmental institutions on financial subsidies, step-by-step guidelines, home evaluation tools, and participation guidelines. Lastly, the research categorised and evaluated the interfaces designed to deliver the information to the Dutch homeowners’ associations. The research also explored the barriers and drivers related to trust issues in EERs as the correlation between trust and information and communication emerged as one of the most prominent factors affecting EERs' acceptance. The paper analysed the online information sources based on readability, credibility, and interactivity, focusing on accessibility and the ability to generate tailor-made suggestions. The analysis revealed that the online information sources are disorganised and dispersed. The online platforms rarely provide information on prior case studies and more on financial subsidies, guidelines, and EER benefits. Lastly, we discussed the main barriers and potential solutions for these challenges.","Communication; Energy efficiency retrofits; Home-owners associations; information on energy transition","en","conference paper","Rijksdienst voor Ondernemend Nederland (RVO)","","","","","","","","","Management in the Built Environment","Design & Construction Management","","",""
"uuid:85745663-fc53-43f8-8cec-8fc1b4d2bd34","http://resolver.tudelft.nl/uuid:85745663-fc53-43f8-8cec-8fc1b4d2bd34","Benchmarking Data Efficiency and Computational Efficiency of Temporal Action Localization Models","Warchocki, J. (Student TU Delft); Oprescu, T. (Student TU Delft); Wang, Y. (Student TU Delft); Dămăcuș, A. (Student TU Delft); Misterka, P.M. (Student TU Delft); Bruintjes, R. (TU Delft Pattern Recognition and Bioinformatics); Lengyel, A. (TU Delft Pattern Recognition and Bioinformatics); Strafforello, O. (TU Delft Pattern Recognition and Bioinformatics); van Gemert, J.C. (TU Delft Pattern Recognition and Bioinformatics)","","2023","In temporal action localization, given an input video, the goal is to predict which actions it contains, where they begin, and where they end. Training and testing current state-of- the-art deep learning models requires access to large amounts of data and computational power. However, gathering such data is challenging and computational resources might be limited. This work explores and measures how current deep temporal action localization models perform in settings constrained by the amount of data or computational power. We measure data efficiency by training each model on a subset of the training set. We find that TemporalMaxer outperforms other models in data-limited settings. Furthermore, we recommend TriDet when training time is limited. To test the efficiency of the models during inference, we pass videos of different lengths through each model. We find that TemporalMaxer requires the least computational resources, likely due to its simple architecture.","","en","conference paper","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:76b71fcb-b818-4187-8e0f-e14ab72342da","http://resolver.tudelft.nl/uuid:76b71fcb-b818-4187-8e0f-e14ab72342da","Crystal Growth and Physical Properties of Hybrid CoSn-YCo6Ge6 Structure Type LnxCo3(Ge1-ySny)3 (Ln = Y, Gd)","Bravo, Moisés (Baylor University); McCandless, Gregory T. (Baylor University); Baumbach, Ryan E. (Florida State University); Wang, Y. (TU Delft QN/Ali Lab; Baylor University; Kavli institute of nanoscience Delft); Ali, M.N. (TU Delft QN/Ali Lab; Baylor University; Kavli institute of nanoscience Delft); Chan, Julia Y. (Baylor University)","","2023","There is an ongoing interest in kagome materials because they offer tunable platforms at the intersection of magnetism and electron correlation. Herein, we examine single crystals of new kagome materials, LnxCo3(Ge1-ySny)3 (Ln = Y, Gd; y = 0.11, 0.133), which were produced using the Sn flux-growth method. Unlike many of the related chemical analogues with the LnM6X6 formula (M = transition metal and X = Ge, Sn), the Y and Gd analogues crystallize in a hybrid YCo6Ge6/CoSn structure, with Sn substitution. While the Y analogue displays temperature-independent paramagnetism, magnetic measurements of the Gd analogue reveal a magnetic moment of 8.48 μB, indicating a contribution from both Gd and Co. Through anisotropic magnetic measurements, the direction of Co-magnetism can be inferred to be in plane with the kagome net, as the Co contribution is only along H//a. Crystal growth and structure determination of YxCo3(Ge,Sn)3 and GdxCo3(Ge,Sn)3, two new hybrid kagome materials of the CoSn and YCo6Ge6 structure types. Magnetic properties, heat capacity, and resistivity on single crystals are reported.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-23","","","QN/Ali Lab","","",""
"uuid:1f5fcf5b-983b-40d4-a7e5-68e3413b10e7","http://resolver.tudelft.nl/uuid:1f5fcf5b-983b-40d4-a7e5-68e3413b10e7","Nowcasting of Extreme Precipitation Using Deep Generative Models","Bi, Haoran (Student TU Delft); Kyryliuk, Maksym (Student TU Delft); Wang, Zhiyi (Student TU Delft); Meo, C. (TU Delft Signal Processing Systems); Wang, Y. (TU Delft Signal Processing Systems); Imhoff, Ruben (Deltares); Uijlenhoet, R. (TU Delft Water Resources); Dauwels, J.H.G. (TU Delft Signal Processing Systems)","","2023","Nowcasting is an observation-based method that uses the current state of the atmosphere to forecast future weather conditions over several hours. Recent studies have shown the promising potential of using deep learning models for precipitation nowcasting. In this paper, novel deep generative models are proposed for precipitation nowcasting. These models are equipped with extreme-value losses to more reliably predict extreme precipitation events. The proposed deep generative model contains a Vector Quantization Generative Adversarial Network and a Transformer (""VQGAN + Transformer""). For enhanced modeling and forecasting of extreme events, Extreme Value Loss (EVL) is incorporated in the autore-gressive Transformer. The numerical results show that the proposed model achieves comparable performance with the state-of-the-art conventional nowcasting method PySTEPS for predicting nominal values. By incorporating an EVL, the proposed model yields more accurate nowcasting of extreme precipitation.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-05","","","Signal Processing Systems","","",""
"uuid:f30423a5-5a9e-4c13-9fc4-3cd92fae5067","http://resolver.tudelft.nl/uuid:f30423a5-5a9e-4c13-9fc4-3cd92fae5067","Stable water isotopes and tritium tracers tell the same tale:: no evidence for underestimation of catchment transit times inferred by stable isotopes in StorAge Selection (SAS)-function models","Wang, S. (TU Delft Water Resources); Hrachowitz, M. (TU Delft Water Resources); Schoups, G.H.W. (TU Delft Water Resources); Stumpp, Christine (BOKU-University of Natural Resources and Life Sciences)","","2023","Stable isotopes (I18O) and tritium (3H) are frequently used as tracers in environmental sciences to estimate age distributions of water. However, it has previously been argued that seasonally variable tracers, such as I18O, generally and systematically fail to detect the tails of water age distributions and therefore substantially underestimate water ages as compared to radioactive tracers such as 3H. In this study for the Neckar River basin in central Europe and based on a >20-year record of hydrological, I18O and 3H data, we systematically scrutinized the above postulate together with the potential role of spatial aggregation effects in exacerbating the underestimation of water ages. This was done by comparing water age distributions inferred from I18O and 3H with a total of 21 different model implementations, including time-invariant, lumped-parameter sine-wave (SW) and convolution integral (CO) models as well as StorAge Selection (SAS)-function models (P-SAS) and integrated hydrological models in combination with SAS functions (IM-SAS). We found that, indeed, water ages inferred from I18O with commonly used SW and CO models are with mean transit times (MTTs) of g1/4g1-2 years substantially lower than those obtained from 3H with the same models, reaching MTTs of g1/410 years. In contrast, several implementations of P-SAS and IM-SAS models not only allowed simultaneous representations of storage variations and streamflow as well as I18O and 3H stream signals, but water ages inferred from I18O with these models were, with MTTs of g1/4g11-17 years, also much higher and similar to those inferred from 3H, which suggested MTTs of g1/4g11-13 years. Characterized by similar parameter posterior distributions, in particular for parameters that control water age, P-SAS and IM-SAS model implementations individually constrained with I18O or 3H observations exhibited only limited differences in the magnitudes of water ages in different parts of the models and in the temporal variability of transit time distributions (TTDs) in response to changing wetness conditions. This suggests that both tracers lead to comparable descriptions of how water is routed through the system. These findings provide evidence that allowed us to reject the hypothesis that I18O as a tracer generally and systematically ""cannot see water older than about 4 years""and that it truncates the corresponding tails in water age distributions, leading to underestimations of water ages. Instead, our results provide evidence for a broad equivalence of I18O and 3H as age tracers for systems characterized by MTTs of at least 15-20 years. The question to which degree aggregation of spatial heterogeneity can further adversely affect estimates of water ages remains unresolved as the lumped and distributed implementations of the IM-SAS model provided inconclusive results. Overall, this study demonstrates that previously reported underestimations of water ages are most likely not a result of the use of I18O or other seasonally variable tracers per se. Rather, these underestimations can largely be attributed to choices of model approaches and complexity not considering transient hydrological conditions next to tracer aspects. Given the additional vulnerability of time-invariant, lumped SW and CO model approaches in combination with I18O to substantially underestimate water ages due to spatial aggregation and potentially other still unknown effects, we therefore advocate avoiding the use of this model type in combination with seasonally variable tracers if possible and instead adopting SAS-based models or time-variant formulations of CO models.","","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:6e1cb924-6f47-4c46-b7d6-9fd13a6657d1","http://resolver.tudelft.nl/uuid:6e1cb924-6f47-4c46-b7d6-9fd13a6657d1","A Mini Review of Ceramic-Based MOF Membranes for Water Treatment","Wang, Xueling (Zhengzhou University); Wang, Man (Zhengzhou University); Chen, M. (TU Delft Sanitary Engineering); Zhang, Yatao (Zhengzhou University)","","2023","Ceramic membranes have been increasingly employed in water treatment owing to their merits such as high-stability, anti-oxidation, long lifespan and environmental friendliness. The application of ceramic membranes mainly focuses on microfiltration and ultrafiltration processes, and some precise separation can be achieved by introducing novel porous materials with superior selectivity. Recently, metal–organic frameworks (MOFs) have developed a wide spectrum of applications in the fields of the environment, energy, water treatment and gas separation due to the diversity and tunable advantages of metal clusters and organic ligands. Although the issue of water stability in MOF materials inhibits the development of MOF membranes in water treatment, researchers still overcome many obstacles to advance the application of MOF membranes in water treatment processes. To the best of our knowledge, there is still a lack of a reviews on the development process and prospects of ceramic-based MOF membranes for water treatment. Therefore, in this review, we mainly summarize the fabrication method for ceramic-based MOF membranes and their application in water treatment, such as water/salt separation, pollutant separation, heavy metal separation, etc. Following this, based on the high structural, thermal and chemical stability of ceramic substrates, and the high controllability of MOF materials, the superiority and insufficient use of ceramic-based MOF membranes in the field of water treatment are critically discussed.","ceramic membrane; metal–organic framework; water treatment; fabrication method","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:03dd1891-0d72-4e6b-9d6b-6f0dc87491ca","http://resolver.tudelft.nl/uuid:03dd1891-0d72-4e6b-9d6b-6f0dc87491ca","Improved Wordpcfg for Passwords with Maximum Probability Segmentation","Li, Wenting (Peking University); Yang, Jiahong (Peking University); Cheng, Haibo (Peking University); Wang, Ping (Peking University); Liang, K. (TU Delft Cyber Security)","","2023","Modeling password distributions is a fundamental problem in password security, benefiting the research and applications on password guessing, password strength meters, honey password vaults, etc. As one of the best segment-based password models, WordPCFG has been proposed to capture individual semantic segments (called words) in passwords. However, we find WordPCFG does not address well the ambiguity of password segmentation by maximum matching, leading to the unreasonable segmentation of many password and further the inaccuracy of modeling password distributions. To address the ambiguity, we improve WordPCFG by maximum probability segmentation with A*-like pruning algorithm. The experimental results show that the improved WordPCFG cracks 99.26%–99.95% passwords, with nearly 5.67%–18.01% improvement.","Password; Probabilistic context-free grammar; maximum probability segmentation","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-05","","","Cyber Security","","",""
"uuid:9e01529f-e133-4794-bb32-eb525b08ede2","http://resolver.tudelft.nl/uuid:9e01529f-e133-4794-bb32-eb525b08ede2","Reinforcement Learning for Safe Robot Control using Control Lyapunov Barrier Functions","Du, D. (TU Delft Robot Dynamics; Harbin Institute of Technology); Han, S. (Student TU Delft); Qi, Naiming (Harbin Institute of Technology); Ammar, Haitham Bou (Huawei Technologies; University College London (UCL)); Wang, Jun (University College London (UCL)); Pan, W. (TU Delft Robot Dynamics; The University of Manchester)","","2023","Reinforcement learning (RL) exhibits impressive performance when managing complicated control tasks for robots. However, its wide application to physical robots is limited by the absence of strong safety guarantees. To overcome this challenge, this paper explores the control Lyapunov barrier function (CLBF) to analyze the safety and reachability solely based on data without explicitly employing a dynamic model. We also proposed the Lyapunov barrier actor-critic (LBAC), a model-free RL algorithm, to search for a controller that satisfies the data-based approximation of the safety and reachability conditions. The proposed approach is demonstrated through simulation and real-world robot control experiments, i.e., a 2D quadrotor navigation task. The experimental findings reveal this approach's effectiveness in reachability and safety, surpassing other model-free RL methods.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-04","","","Robot Dynamics","","",""
"uuid:3fc9087b-c18a-4628-8e5d-723bb6442040","http://resolver.tudelft.nl/uuid:3fc9087b-c18a-4628-8e5d-723bb6442040","GazeNeRF: 3D-Aware Gaze Redirection with Neural Radiance Fields","Ruzzi, Alessandro (ETH Zürich); Shi, X. (TU Delft Pattern Recognition and Bioinformatics); Wang, Xi (ETH Zürich); Li, Gengyan (ETH Zürich); De Mello, Shalini (Nvidia); Chang, Hyung Jin (University of Birmingham); Zhang, X. (TU Delft Pattern Recognition and Bioinformatics); Hilliges, Otmar (ETH Zürich)","O'Conner, Lisa (editor)","2023","We propose GazeNeRF, a 3D-aware method for the task of gaze redirection. Existing gaze redirection methods operate on 2D images and struggle to generate 3D consistent results. Instead, we build on the intuition that the face region and eyeballs are separate 3D structures that move in a coordinated yet independent fashion. Our method leverages recent advancements in conditional image-based neural radiance fields and proposes a two-stream architecture that predicts volumetric features for the face and eye regions separately. Rigidly transforming the eye features via a 3D rotation matrix provides fine-grained control over the desired gaze angle. The final, redirected image is then attained via differentiable volume compositing. Our experiments show that this architecture outperforms naively conditioned NeRF baselines as well as previous state-of-the-art 2D gaze redirection methods in terms of redirection accuracy and identity preservation. Code and models will be released for research purposes.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-22","","","Pattern Recognition and Bioinformatics","","",""
"uuid:9615b9aa-9cf6-4e35-ad42-125756036456","http://resolver.tudelft.nl/uuid:9615b9aa-9cf6-4e35-ad42-125756036456","Stability Analysis of Triple Active Bridge Converter with Hybrid Loads and Different Control Strategies","Yu, Haoyuan (Aalborg University); Zhang, Hanwen (Aalborg University); Wang, Yanbo (Aalborg University); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Chen, Zhe (Aalborg University); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2023","This article investigates the stability of triple active bridge (TAB) converter with different types of loads. In this paper, port2 of TAB converter adopts voltage control to supply a constant power load (CPL), and port3 uses voltage control to supply a resistor or uses current control to supply a battery. Then, an extra element theorem-based (EET) modelling method based on the small signal model of the TAB converter is developed to derive the output impedance of different cases. The AC sweeping is implemented to validate the effectiveness of derivation. Furthermore, the impedance-based analysis method is applied to analyze the system stability. The analysis result shows that the instability issue caused by CPL at port2 can be suppressed by reducing the resistance load value at port3 or output current of port3. Simulation and experimental results are given to validate the stability analysis.","triple active bridge converter; extra element theorem; impedance-based analysis method; constant power load","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-22","","","DC systems, Energy conversion & Storage","","",""
"uuid:c6419e6e-47d4-4d3d-a31c-e4dc8143535b","http://resolver.tudelft.nl/uuid:c6419e6e-47d4-4d3d-a31c-e4dc8143535b","Keyword Search Shareable Encryption for Fast and Secure Data Replication","Wang, Wei (Huazhong University of Science and Technology); Liu, Dongli (Huazhong University of Science and Technology); Xu, Peng (Huazhong University of Science and Technology); Yang, Laurence Tianruo (Huazhong University of Science and Technology); Liang, K. (TU Delft Cyber Security)","","2023","It has become a trend for clients to outsource their encrypted databases to remote servers and then leverage the Searchable Encryption technique to perform secure data retrieval. However, the method has yet to be considered a crucial need for replication on searchable encrypted data. It calls for challenging works on Dynamic Searchable Symmetric Encryption (DSSE) since clients must share the search capability of the encrypted data replicas and guarantee forward and backward privacy. We define a new notion called 'Keyword Search Shareable Encryption' (KS2E2E) and the corresponding security model capturing forward and backward privacy. In our notion, data owners are allowed to share search indexes of the encrypted data with users. A search index will be updated with a new search key before sharing to guarantee the data privacy of the source database. The target database also inherits data search efficiency along with the shared data. We further construct an instance of KS2E called Branch, prove its security, and use real-world datasets to evaluate Branch. The evaluation results show that Branch's performance is comparable to classical DSSE schemes on search efficiency and demonstrate the effectiveness of searching encrypted data replicas from multiple owners.","Cryptography; Data privacy; Databases; Encrypted Data Replication; Encryption; Forward and Backward Privacy; Indexes; Privacy; Searchable Symmetric Encryption; Servers","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-26","","","Cyber Security","","",""
"uuid:c7912a8b-1f91-48f6-b51d-936db204568b","http://resolver.tudelft.nl/uuid:c7912a8b-1f91-48f6-b51d-936db204568b","Probabilistic Risk Assessment for Chance-Constrained Collision Avoidance in Uncertain Dynamic Environments","Khaled Mustafa, K.A. (TU Delft Learning & Autonomous Control); de Groot, O.M. (TU Delft Learning & Autonomous Control); Wang, X. (TU Delft Learning & Autonomous Control); Kober, J. (TU Delft Learning & Autonomous Control); Alonso-Mora, J. (TU Delft Learning & Autonomous Control)","","2023","Balancing safety and efficiency when planning in crowded scenarios with uncertain dynamics is challenging where it is imperative to accomplish the robot's mission without incurring any safety violations. Typically, chance constraints are incorporated into the planning problem to provide probabilistic safety guarantees by imposing an upper bound on the collision probability of the planned trajectory. Yet, this results in an overly conservative behavior on the grounds that the gap between the obtained risk and the specified upper limit is not explicitly restricted. To address this issue, we propose a real-time capable approach to quantify the risk associated with planned trajectories obtained from multiple probabilistic planners, running in parallel, with different upper bounds of the acceptable risk level. Based on the evaluated risk, the least conservative plan is selected provided that its associated risk is below a specified threshold. In such a way, the proposed approach provides probabilistic safety guarantees by attaining a closer bound to the specified risk, while being applicable to generic uncertainties of moving obstacles. We demonstrate the efficiency of our proposed approach, by improving the performance of a state-of-the-art probabilistic planner, in simulations and experiments using a mobile robot in an environment shared with humans.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-04","","","Learning & Autonomous Control","","",""
"uuid:de846c80-7e0e-456d-9b23-9ca55161bae4","http://resolver.tudelft.nl/uuid:de846c80-7e0e-456d-9b23-9ca55161bae4","Wi-Closure: Reliable and Efficient Search of Inter-robot Loop Closures Using Wireless Sensing","Wang, Weiying (Harvard University); Kemmeren, A.C. (Student TU Delft); Son, Daniel (Harvard University); Alonso-Mora, J. (TU Delft Learning & Autonomous Control); Gil, Stephanie (Harvard University)","","2023","In this paper we propose a novel algorithm, Wi-Closure, to improve the computational efficiency and robustness of loop closure detection in multi-robot SLAM. Our approach decreases the computational overhead of classical approaches by pruning the search space of potential loop closures, prior to evaluation by a typical multi-robot SLAM pipeline. Wi-Closure achieves this by identifying candidates that are spatially close to each other measured via sensing over the wireless communication signal between robots, even when they are operating in non-line-of-sight or in remote areas of the environment from one another. We demonstrate the validity of our approach in simulation and in hardware experiments. Our results show that using Wi-closure greatly reduces computation time, by 54.1% in simulation and 76.8% in hardware experiments, compared with a multi-robot SLAM baseline. Importantly, this is achieved without sacrificing accuracy. Using Wi-closure reduces absolute trajectory estimation error by 98.0% in simulation and 89.2% in hardware experiments. This improvement is partly due to Wi-Closure's ability to avoid catastrophic optimization failure that typically occurs with classical approaches in challenging repetitive environments.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-04","","","Learning & Autonomous Control","","",""
"uuid:87c9c52c-5781-4da3-9cd4-8134ce54362b","http://resolver.tudelft.nl/uuid:87c9c52c-5781-4da3-9cd4-8134ce54362b","A General Hierarchical Control System to Model ACC Systems: An Empirical Study","Ruan, Tiancheng (Southeast University); Wang, Hao (Southeast University); Jiang, Rui (Beijing Jiaotong University); Li, Xiaopeng (University of Wisconsin-Madison); Xie, N. (TU Delft Electronic Instrumentation); Xie, Xinjian (Guangzhou Baiyun International Airport Co); Hao, Ruru (Chang'an University); Dong, Changyin (Southeast University)","","2023","Urged by a close future perspective of a traffic flow made of a mix of human-driven vehicles and automated vehicles (AVs), research has recently focused on studying the traffic flow characteristics of Adaptive Cruise Controls (ACCs), the most typical AV. However, in most works, the ACC system is studied under a simplifying and unrealistic assumption, or the ACC system modeled is inaccurate. This paper proposes a general hierarchical control system to model ACC systems with several assumptions based on the deficiencies above. Moreover, a field experiment was conducted, and the corresponding experimental data was used to verify the proposed hierarchical control system and assumptions. In addition, string stability is explored along with sensitivity analyses of control parameters based on an example under the constant time gap policy. The results show that different upper-level controller parameters have different delays, where the delay of the speed is negligible; the introduction of actuator delay and lag in the lower-level controller can significantly improve the model goodness of fit. Furthermore, optimizing the delay and lag in the lower-level controller can significantly enhance the string stability of ACCs than optimizing the control parameters.","Actuators; Adaptive cruise control; Control systems; Data models; Delays; field experiments; hierarchical control system; Mathematical models; Process control; Stability criteria; string stability","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-25","","","Electronic Instrumentation","","",""
"uuid:1547c36b-d00e-49a7-97dc-f0c751794cb5","http://resolver.tudelft.nl/uuid:1547c36b-d00e-49a7-97dc-f0c751794cb5","Tidal amplification and river capture in response to land reclamation in the Ganges-Brahmaputra delta","van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Shanghai Estuarine and Coastal Science Research Center; Deltares); Beemster, J. G.W. (Wageningen University & Research); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); Khan, Z. H. (Institute of Water Modelling); Schrijvershof, R. A. (Deltares; Wageningen University & Research); Hoitink, A. J.F. (Wageningen University & Research)","","2023","At a global scale, intertidal areas are being reclaimed for agriculture as well as urban expansion, imposing high human pressure on the coastal zone. The Ganges-Brahmaputra Delta (GBD) is an exponent of this development. In this delta, land reclamation accelerated in the 1960's to 1980's, when polders were constructed in areas subject to regular marine flooding. A comprehensive analysis of tidal channel evolution in the southwest GBD reveals how land reclamation leads to tidal amplification, channel shoaling, bank erosion, and interaction between channels in which one tidal river captures the storage area of a neighbouring river. We identify-two positive feedback mechanisms that govern these morphological changes. First, reclaiming intertidal areas results in immediate loss of tidal storage, which leads to amplification and faster propagation of the tides. In systems with abundant sediment supply, the blind tidal channels progressively fill in with sediment, leading to a continued loss of tidal storage and therefore further distorting the tides. Secondly, when intertidal areas of parallel (and inter-connected) river delta distributaries are asynchronously or unevenly reclaimed, one channel distributary may expand its intertidal area at the expense of the other. This is initiated by an increasing propagation speed of the tidal wave in the partially reclaimed distributary, travelling into the non-reclaimed distributary through connecting channels. These connecting channels progressively expand while the pristine channel shoals, and potentially degenerates. Both positive feedback loops are very stable and are responsible for pluvial flooding of polders, large-scale bank erosion, and poorly navigable primary waterways, including the navigation channel accessing Bangladesh's second-largest port. Interventions aiming to solve these problems have to account for the complex positive feedback mechanisms identified in this paper and be nature-based and holistic.","Estuary; Fine sediments; Ganges-Brahmaputra delta; Human impacts; Land reclamations; Tidal amplification","en","journal article","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:fe4c27ff-85cb-4084-8dfb-476fa7117f16","http://resolver.tudelft.nl/uuid:fe4c27ff-85cb-4084-8dfb-476fa7117f16","Investigating Effects of Heterogeneity and Fracture Distribution on Two-Phase Flow in Fractured Reservoir with adaptive time strategy","Wang, Lu Yu (The Hong Kong Polytechnic University; GeoRessources Lab); Chen, Wei Zhong (Chinese Academy of Sciences); Zhang, Yan Jun (College of Petroleum Engineering; Xi'an Shiyou University); Zhang, Xiao Dong (GeoRessources Lab); Vuik, Cornelis (TU Delft Delft Institute of Applied Mathematics)","","2023","Modeling of fluid flow in porous media is a pillar in geoscience applications. Previous studies have revealed that heterogeneity and fracture distribution have considerable influence on fluid flow. In this work, a numerical investigation of two-phase flow in heterogeneous fractured reservoir is presented. First, the discrete fracture model is implemented based on a hybrid-dimensional modeling approach, and an equivalent continuum approach is integrated in the model to reduce computational cost. A multilevel adaptive strategy is devised to improve the numerical robustness and efficiency. It allows up to 4-levels adaption, where the adaptive factors can be modified flexibly. Then, numerical tests are conducted to verify the the proposed method and to evaluate its performance. Different adaptive strategies with 3-levels, 4-levels and fixed time schemes are analyzed to evaluate the computational cost and convergence history. These evaluations demonstrate the merits of this method compared to the classical method. Later, the heterogeneity in permeability field, as well as initial saturation, is modeled in a layer model, where the effect of layer angle and permeability on fluid flow is investigated. A porous medium containing multiple length fractures with different distributions is simulated. The fine-scale fractures are upscaled based on the equivalent approach, while the large-scale fractures are retained. The conductivity of the rock matrix is enhanced by the upscaled fine-scale fractures. The difference of hydraulic property between homogeneous and heterogeneous situations is analyzed. It reveals that the heterogeneity may influence fluid flow and production, while these impacts are also related to fracture distribution and permeability.","Fracture distribution; Fractured porous media; Heterogeneity; Multilevel adaptive scheme; Two-phase flow","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-04-03","","","","","",""
"uuid:337bdec5-c994-4d0c-ad23-b24ded0e0a20","http://resolver.tudelft.nl/uuid:337bdec5-c994-4d0c-ad23-b24ded0e0a20","Investigating rural public spaces with cultural significance using morphological, cognitive and behavioural data","Bai, N. (TU Delft Heritage & Values); Nourian, Pirouz (TU Delft Design Informatics); Pereira Roders, A. (TU Delft Heritage & Values); Bunschoten, Raoul (Technical University of Berlin); Huang, Weixin (Tsinghua University); Wang, Lu (Tsinghua University)","","2023","During the rural [re]vitalization process in China, national strategies required rural public spaces with cultural significance to be identified before planning decision-making. However, places identified as culturally significant by planners and visitors can differ from the ones mostly used and valued by locals. Even if there is a growing interest in integrating local perspectives and experiences in planning, studies seldom discuss and compare openly the adequacy of spatial configuration, cognition and behaviour to support it. This study took Anyi Historic Village Cluster as a case study to empirically investigate rural public spaces with three distinct, yet related approaches: (1) Morphological: spatial network centralities based on space syntax; (2) Cognitive: Lynchian village images with semi-structured interviews; (3) Behavioural: spatiotemporal occupation patterns using Wi-Fi positioning tracking. Significant places valued and used by locals and non-locals were detected with the multi-source data. Furthermore, multivariant regression models managed to characterize the relationship among different aspects of investigated rural public spaces, which also helped diagnose places of interest to prioritize in planning, demonstrating the advantage of integrating the sources of information in practice instead of studying them apart. Results can also assist rural planning on how to identify what to preserve, what to enhance, and how to develop such spaces, without overlooking the local needs or losing the rural identity.","Rural Planning; Space Syntax; Cognition; Big Data; Activity Space","en","journal article","","","","","","","","","","","Heritage & Values","","",""
"uuid:d3a38c97-88fb-4d64-bdc1-756bbe5d1c78","http://resolver.tudelft.nl/uuid:d3a38c97-88fb-4d64-bdc1-756bbe5d1c78","The techno-economic integrability of high-temperature heat pumps for decarbonizing process heat in the food and beverages industry","Dumont, Marina (Universiteit Leiden); Wang, Ranran (Universiteit Leiden); Wenzke, Diana (Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Blok, K. (TU Delft Energie and Industrie); Heijungs, Reinout (Universiteit Leiden; Vrije Universiteit Amsterdam)","","2023","High-temperature heat pumps (HTHPs) are an emerging technology to improve overall process efficiency and reduce energy demand while enabling a switch from fossil fuels to renewable electricity. New industrial HTHP technologies aim to achieve an output heat temperature of 250 °C, suitable for decarbonising the food and beverages industry considering its temperature requirements of <250 °C. Here, we employ a bottom-up approach to investigate the techno-economic feasibility of integrating new HTHP technologies into heat processes of the German food and beverages industry and estimate emissions reduction potentials under waste heat scenarios. Our results indicate that the new HTHP technologies could meet 12 TWh of process heat demand in the German food and beverages industry and cut emissions by 9% considering Germany's current electricity fuel mix. A modest carbon tax of 38 €/t CO2 eq. or higher makes the HTHPs cost-competitive with an optimised fossil fuel-based alternative.","GHG emissions abatement; High-temperature heat pumps; Industrial decarbonisation; Techno-economic assessment","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Energie and Industrie","","",""
"uuid:8bc48e89-d9a9-4024-b4cb-01c0982e70e7","http://resolver.tudelft.nl/uuid:8bc48e89-d9a9-4024-b4cb-01c0982e70e7","Reviving the rock-salt phases in Ni-rich layered cathodes by mechano-electrochemistry in all-solid-state batteries","Wang, Zaifa (Yanshan University); Wang, Zhenyu (Guilin Electrical Equipment Scientific Research Institut, Gulin); Xue, Dingchuan (The Pennsylvania State University); Zhao, Jun (Yanshan University); Zhang, Xuedong (Xiangtan University, Xiangtan); Geng, Lin (Yanshan University); Li, Yanshuai (Yanshan University); Du, Congcong (Yanshan University); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2023","The rock-salt phase (RSP) formed on the surface of Ni-rich layered cathodes in liquid-electrolyte lithium-ion batteries is conceived to be electrochemically ""dead"". Here we show massive RSP forms in the interior of LiNixMnyCo(1−x-y)O2 (NMC) crystals in sulfide based all solid state batteries (ASSBs), but the RSP remains electrochemically active even after long cycles. The RSP and the layered structure constitute a two-phase mixture, a material architecture that is distinctly different from the RSP in liquid electrolytes. The tensioned layered phase affords an effective percolation channel into which lithium is squeezed out of the RSPs by compressive stress, rendering the RSPs electrochemically active. Consequently, the ASSBs with predominant RSP in the NMC cathode deliver remarkable long cycle life of 4000 cycles at high areal capacity of 4.3 mAh/cm2. Our study unveils distinct mechano-electrochemistry of RSPs in ASSBs that can be harnessed to enable high energy density and durable ASSBs.","All-solid-state batteries; Mechano-electrochemistry; Ni-rich cathodes; Rock-salt phases","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","RST/Storage of Electrochemical Energy","","",""
"uuid:10b4e1ea-9420-4e98-8cf6-fa75fdd9ed9d","http://resolver.tudelft.nl/uuid:10b4e1ea-9420-4e98-8cf6-fa75fdd9ed9d","A data-driven high spatial resolution model of biomass accumulation and crop yield: Application to a fragmented desert-oasis agroecosystem","Chen, Qiting (Chinese Academy of Sciences); Jia, Li (Chinese Academy of Sciences); Menenti, M. (TU Delft Optical and Laser Remote Sensing; Chinese Academy of Sciences); Hu, Guangcheng (Chinese Academy of Sciences); Wang, Kun (Chinese Academy of Sciences); Yi, Zhiwei (Chinese Academy of Sciences); Zhou, Jie (Central China Normal University); Peng, Fei (Chinese Academy of Sciences, Lanzhou); Ma, Shaoxiu (Chinese Academy of Sciences, Lanzhou)","","2023","Information on crop yield is important for food security, in particular under the conditions of climate change and growing population worldwide. We developed a new fully distributed, high spatial resolution, model of biomass accumulation and crop yield applicable to a highly heterogeneous desert-oasis agroecosystem. The bulk of required input data is obtained by retrieving pixel-wise biogeophysical variables from a suite of very diverse satellite data. Both temperature and water stress conditions at field-scale are given full consideration, while the model was designed to strike a balance between model applicability and satisfactory characterization of the heterogeneous desert-oasis system to estimate field-scale yield. The development of this model relies on three main innovations. First, the start and end of the growing season were estimated for each pixel by calibrating the high spatial and temporal resolution observations of Normalized Difference Vegetation Index (NDVI) by Sentinal-2 (S2) MSI (Multi-Spectral Instrument) against limited local phenological information. Second, to monitor crop water stress, account taken of irrigation, a process-based water and energy balance model was applied to estimate the actual evapotranspiration (ET). This requires knowledge of soil water availability, which is characterized by downscaling the ASCAT (Advanced SCATterrometer) soil moisture data product. To capture the dominant features of the eco-hydrological conditions in the desert and oasis agroecosystem, ET was further downscaled from the 1 km resolution. Third, likewise the water stress indicator, the air temperature stress indicator was mapped after characterizing the thermal contrast and heterogeneity of the desert-oasis system, by generating time series of air temperature at 1 km spatial resolution using the MODIS (Moderate Resolution Imaging Spectroradiometer) Land Surface Temperature (LST) data product. In the temporal dimension, gaps were mitigated by applying time series analysis techniques to reconstruct cloud-free time series of LST, NDVI, fAPAR and albedo. These innovations add up to a high resolution characterization of crop response to the geospatial variability of weather and climate forcing in the desert-oasis agroecosystem. The model was applied to the dominant crops, i.e., spring wheat, maize, sunflower, and melon, in the oases of the Shiyang River Basin (northwestern China) characterized by a rather fragmented land use. The high resolution of pixel-wise ecohydrological parameters, i.e., crop phenology, temperature stress and water stress factors successfully reflect differences of crops with different phenology and location in the oases. The relative errors for wheat and maize yields compared to the census data are less than 5% at district level. At the county level, the relative errors of wheat yields of Liangzhou, Minqin, Gulang, Jinchuan, and Yongchang equal to 0.87%, 24.2%, 9.7%, 12.5%, and 7.2%. For maize, the dominant crop, the error on estimated yields was less than 5%, except in Gulang. The relative error on estimated yield for sunflower was less than 10% compared to agricultural census data. The relative error on estimated melon yield was 16%. This performance highlights the applicability of the model to estimate field-scale yields in agroecosystems characterized by fragmented land use.","Crop yield estimation; Heterogeneous agroecosystem; High resolution; Multi-source remote sensing data","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:76fb06db-5cf1-41de-b804-ec689ec424df","http://resolver.tudelft.nl/uuid:76fb06db-5cf1-41de-b804-ec689ec424df","Self-healing and corrosion-sensing coatings based on pH-sensitive MOF-capped microcontainers for intelligent corrosion control","Liu, Tong (University of Science and Technology Beijing); Zhang, Dawei (University of Science and Technology Beijing); Zhang, Rongjun (University of Science and Technology Beijing); Wang, Jinke (University of Science and Technology Beijing); Ma, Lingwei (University of Science and Technology Beijing); Keil, Patrick (BASF SE); Mol, J.M.C. (TU Delft Team Arjan Mol); Li, Xiaogang (University of Science and Technology Beijing)","","2023","Organic coatings are one of the most used and versatile technologies to mitigate corrosion of metals. However, organic coatings are susceptible to defects and damages that may not be easily detected. If not repaired timely, these defects may develop into major coating failures due to corrosion occurring in the damaged region, thereby limiting the lifetime of the to be protected structure. Thus, the development of smart coatings that can accurately identify corrosion location and reliably recover the damage autonomously is of particular interest. Herein, we reported a robust, corrosion-sensing and self-healing coating which incorporated pH-sensitive ZIF-8-capped CaCO3 microcontainers containing the healing agent tung oil (TO) and the corrosion indicator/inhibitor 1,10-phenanthrolin-5-amine (APhen). The spontaneous leakage of incorporated TO and APhen was restrained, and the release initiated when local pH variation occurred. The corrosion protection performance of the coatings implanted with different contents of smart microcontainers were evaluated. The intact epoxy coating containing 7.5 wt% of the microcontainers exhibited the best protection performance with low water absorption (0.65 wt%), low O2 permeability (0.21 × 10–15 cm3 cm cm−2 s−1 Pa−1), and a high storage modulus (3.0 GPa). Electrochemical impedance spectroscopy (EIS) measurements in 3.5 wt% NaCl solution demonstrated superior durability of the composite coating after self-healing. The immersion test and neutral salt spray test confirmed the coating can accurately report corrosion sites via coloration.","Corrosion protection; Corrosion-sensing; Organic coating; pH-sensitive; Self-healing coatings","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-05-18","","","Team Arjan Mol","","",""
"uuid:c5440135-3b33-4507-a6c9-e9c8f253cbae","http://resolver.tudelft.nl/uuid:c5440135-3b33-4507-a6c9-e9c8f253cbae","On the interlayer toughening of carbon fibre/epoxy composites using surface-activated ultra-thin PEEK films","Quan, D. (TU Delft Structural Integrity & Composites; Shandong University); Wang, Guilong (Shandong University); Zhao, Guoqun (Shandong University); Alderliesten, R.C. (TU Delft Structural Integrity & Composites)","","2023","The exceptional mechanical properties of Polyether-ether-ketone(PEEK) polymers make them ideal candidates for interlayer toughening of carbon fibre/epoxy composites. Herein, ultra-thin PEEK films with a thickness of 8μm, 18μm and 25μm were used for interlayer toughening of an aerospace-grade carbon fibre/epoxy composite. The mode-I and mode-II fracture behaviour of the interleaved laminates were investigated, with the fracture mechanisms being investigated. The surfaces of the PEEK films were treated by a UV-irradiation technique to enhance their intrinsically low surface activities. This significantly increased the adhesion at the interface between the PEEK interlayers and the composite matrix. A topography analysis on the fracture surfaces revealed extensive damage of the PEEK interlayers during the fracture process of the laminates. Owing to the exceptional properties of the PEEK films, significant enhancements in the mode-I and mode-II fracture properties of the laminates were obtained, i.e. the mode-I and mode-II fracture energies were significantly increased by 227% and 441%, respectively. Overall, the UV-treated PEEK films proved superior effectivenesses for laminate toughening when compared to the other state-of-the-art interlayer materials.","Fracture toughness; Interlayer toughening; Polymer-matrix composites (PMCs); Ultra-thin films","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-19","","","Structural Integrity & Composites","","",""
"uuid:c63408d6-be94-477c-af3c-c9cf3e46f72f","http://resolver.tudelft.nl/uuid:c63408d6-be94-477c-af3c-c9cf3e46f72f","Experimental analysis of ballast bed state in newly constructed railways after tamping and stabilizing operation","Xiao, Hong (Beijing Jiaotong University); Zhang, Zhihai (Beijing Jiaotong University); Zhu, Yajie (China Railway Beijing Bureau Group); Gan, Tiancheng (China Railway Beijing Bureau Group); Wang, Haoyu (TU Delft Mechanics and Physics of Structures)","","2023","Before the operation of newly constructed railways, tamping and stabilizing machines should be used to improve the quality of ballast beds. With the expansion of the railway network and increase of speeds and axle loads, higher quality and efficiency for tamping and stabilizing operation are required. However, previous studies did not involve the effects and parameters of three-sleeper tamping and stabilizing operation under complex working conditions. In the paper, the effect of a three-sleeper tamping and stabilizing machine on the ballast bed state has been studied by performing field experiments. The effect of important factors, including tamping modes, stabilizing frequency, and track lifting amount, are discussed in detail. The results show that the tamping operation on newly constructed railways causes a reduction of the lateral resistance by 56.5 % and a reduction of lateral resistance work by 64.9 %. After the stabilizing operation, the lateral resistance and lateral resistance work are increased by 168.6 % and 209.8 %, respectively. The tamping and stabilizing operation can significantly increase the support stiffness of ballast beds, which meets the requirements of train operation. Meanwhile, 2X tamping mode is more beneficial to improve ballast resistance. Besides, it is reasonable for a stabilizing frequency of 25 Hz to be used for newly constructed railways. The track lifting amount also has a large effect on the ballast bed quality, and it is recommended to keep the lift amount in the range of 20 mm ∼ 30 mm to achieve a better tamping quality.","Longitudinal and lateral resistance; Newly constructed railway; Stabilizing frequency; Support stiffness; Tamping and stabilizing operation; Tamping mode","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Mechanics and Physics of Structures","","",""
"uuid:54e72996-74cc-46e6-b5a9-e7a14ce6e71f","http://resolver.tudelft.nl/uuid:54e72996-74cc-46e6-b5a9-e7a14ce6e71f","Understanding the interaction of nucleotides with UVC light: an insight from quantum chemical calculation-based findings","Tan, C. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology); Wang, S. (TU Delft Bio-Electronics; Southern University of Science and Technology); Yang, Huiru (Southern University of Science and Technology); Huang, Qianming (Southern University of Science and Technology); Li, Shizhen (Southern University of Science and Technology); Liu, X. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology); Ye, H. (Southern University of Science and Technology); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2023","Short-wave ultraviolet (also called UVC) irradiation is a well-adopted method of viral inactivation due to its ability to damage genetic material. A fundamental problem with the UVC inactivation method is that its mechanism of action on viruses is still unknown at the molecular level. To address this problem, herein we investigate the response mechanism of genome materials to UVC light by means of quantum chemical calculations. The spectral properties of four nucleotides, namely, adenine, cytosine, guanine, and uracil, are mainly focused on. Meanwhile, the transition state and reaction rate constant of uracil molecules are also considered to demonstrate the difficulty level of adjacent nucleotide reaction without and with UVC irradiation. The results show that the peak wavelengths are 248.7 nm, 226.1 nm (252.7 nm), 248.3 nm, and 205.8 nm (249.2 nm) for adenine, cytosine, guanine, and uracil nucleotides, respectively. Besides, the reaction rate constants of uracil molecules are 6.419 × 10−49 s−1 M−1 and 5.436 × 1011 s−1 M−1 for the ground state and excited state, respectively. Their corresponding half-life values are 1.56 × 1048 s and 1.84 × 10−12 s. This directly suggests that the molecular reaction between nucleotides is a photochemical process and the reaction without UVC irradiation almost cannot occur.","","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:5061f633-d256-4526-9c61-d55a5f147011","http://resolver.tudelft.nl/uuid:5061f633-d256-4526-9c61-d55a5f147011","Synergy of phosphate recovery from sludge-incinerated ash and coagulant production by desalinated brine","Wang, Xiangyang (Beijing University of Civil Engineering & Architecture); Shi, Chen (Beijing University of Civil Engineering & Architecture); Hao, Xiaodi (Beijing University of Civil Engineering & Architecture); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology; Beijing University of Civil Engineering & Architecture); Wu, Yuanyuan (Beijing University of Civil Engineering & Architecture)","","2023","Wet-chemical approach is widely applied for phosphate recovery from incinerated ash of waste activated sludge (WAS), along with metals removed/recovered. The high contents of both aluminum (Al) and iron (Fe) in WAS-incinerated ash should be suitable for producing coagulants with some waste anions like Cl− and SO42− With acid (HCl) leaching and metals’ removing, approximately 88 wt% of phosphorus (P) in the ash could be recovered as hydroxylapatite (HAP: Ca5(PO4)3OH); Fe3+ in the acidic leachate could be selectively removed/recovered by extraction with an organic solvent of tributyl phosphate (TBP), and thus a FeCl3-based coagulant could be synthesized by stripping the raffinate with the original brine (containing abundant Cl− and SO42−). Furthermore, a liquid poly-aluminum chloride (PAC)-based coagulant could also be synthesized with Al3+ removed from the ash and the brine, which behaved almost the same in the coagulation performance as a commercial coagulant on both phosphate and turbidity removals. Both P-recovery from the ash and coagulant production associated with the brine would enlarge the markets of both ‘blue’ phosphate and ‘green’ coagulants.","Ash; Coagulants; Incineration; Metals’ recovery; Phosphorus recovery; Waste activated sludge (WAS)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-23","","","BT/Environmental Biotechnology","","",""
"uuid:8268358b-84fa-436d-a4f2-0414a72ad73e","http://resolver.tudelft.nl/uuid:8268358b-84fa-436d-a4f2-0414a72ad73e","Modulation of sediment load recovery downstream of Three Gorges Dam in the Yangtze River","Zhu, Chunyan (Shanghai Estuarine and Coastal Science Research Center); Zhang, Yuning (Shanghai Estuarine and Coastal Science Research Center); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Shanghai Estuarine and Coastal Science Research Center; Deltares); Xie, Weiming (Shanghai Estuarine and Coastal Science Research Center); Guo, Leicheng (Shanghai Estuarine and Coastal Science Research Center); Wang, Xianye (Shanghai Estuarine and Coastal Science Research Center); He, Qing (Shanghai Estuarine and Coastal Science Research Center)","","2023","The sediment load in the Yangtze River downstream of the Three Gorges Dam (TGD) has substantially declined in recent decades. The decrease is more profound below the TGD, e.g., a 97% decrease at Yichang, compared with that at the delta apex, 1200 km downstream, e.g., a 75% decrease, implying along-river sediment recovery. Two large river-connected lakes, i.e., Dongting and Poyang Lakes, may play a role in the re-establishment of the river’s morphodynamic equilibrium, but a quantitative data-based understanding of this interaction is not yet available. In this work, we collected a series of field data to quantify the sediment gain and loss in the river-lake system in the middle-lower Yangtze River, and evaluate the lake’s response to the reduction in riverine sediment supply. We find that Dongting Lake and Poyang Lake shifted from net sedimentation to erosion in 2006 and 2000, and back to a sedimentation regime again after 2017 and 2018, respectively. Natural morphodynamic adaptation and sand mining play an important role in the regime changes in the Dongting Lake whereas sand mining dominates the abrupt changes in the Poyang Lake. The Dongting and Poyang Lake contributed maximum by 38% (2015) and 17% (2006) (respectively) to the sediment recovery in the erosion regime, whereas the riverbed erosion dominates the main sediment source. These changes in the relative contribution of sediment sources also indicates a response time of ~ 20 years in the lakes towards a new equilibrium state. It is noteworthy that the lakes’ buffer effects may be overestimated as the supplied sediment from the lakes is rather small compared to the significant dam trapping in the upstream basin and sediment source from downstream degradation. The results imply that river management and restoration should take into account of the river-lake interactions and feedback impact at decadal time scales.","Dongting Lake; Middle-lower Yangtze River; Poyang Lake; Sediment supply; Three gorges dam","en","journal article","","","","","","Doi of Correction document: https://doi.org/10.1007/s44218-023-00021-x","","","","","Environmental Fluid Mechanics","","",""
"uuid:7fd7a2af-2eb1-4589-8a51-f02805183146","http://resolver.tudelft.nl/uuid:7fd7a2af-2eb1-4589-8a51-f02805183146","Chemical signal regulated injectable coacervate hydrogels","Wu, B. (TU Delft ChemE/Advanced Soft Matter; East China University of Science and Technology); Lewis, R.W. (TU Delft ChemE/Advanced Soft Matter); Li, G. (TU Delft ChemE/Advanced Soft Matter); Gao, Yifan (East China University of Science and Technology); Fan, B. (TU Delft ChemE/Advanced Soft Matter); Klemm, B. (TU Delft ChemE/Advanced Soft Matter); Huang, J. (East China University of Science and Technology); Wang, Junyou (East China University of Science and Technology); Cohen Stuart, Martien A. (East China University of Science and Technology); Eelkema, R. (TU Delft ChemE/Advanced Soft Matter)","","2023","In the quest for stimuli-responsive materials with specific, controllable functions, coacervate hydrogels have become a promising candidate, featuring sensitive responsiveness to environmental signals enabling control over sol-gel transitions. However, conventional coacervation-based materials are regulated by relatively non-specific signals, such as temperature, pH or salt concentration, which limits their possible applications. In this work, we constructed a coacervate hydrogel with a Michael addition-based chemical reaction network (CRN) as a platform, where the state of coacervate materials can be easily tuned by specific chemical signals. We designed a pyridine-based ABA triblock copolymer, whose quaternization can be regulated by an allyl acetate electrophile and an amine nucleophile, leading to gel construction and collapse in the presence of polyanions. Our coacervate gels showed not only highly tunable stiffness and gelation times, but excellent self-healing ability and injectability with different sized needles, and accelerated degradation resulting from chemical signal-induced coacervation disruption. This work is expected to be a first step in the realization of a new class of signal-responsive injectable materials.","","en","journal article","","","","","","","","","","","ChemE/Advanced Soft Matter","","",""
"uuid:bcd4947a-a3b4-4e2a-837e-01237bd73c7e","http://resolver.tudelft.nl/uuid:bcd4947a-a3b4-4e2a-837e-01237bd73c7e","Bienzymatic Cascade Combining a Peroxygenase with an Oxidase for the Synthesis of Aromatic Aldehydes from Benzyl Alcohols","Ma, Yunjian (South China University of Technology; Macau University of Science and Technology); Li, Zongquan (South China University of Technology); Zhang, Hao (South China University of Technology); Wong, Vincent Kam Wai (Macau University of Science and Technology); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Yonghua (South China University of Technology; Guangdong Youmei Institute of Intelligent Bio-manufacturing Co, Foshan)","","2023","Aromatic aldehydes are important aromatic compounds for the flavour and fragrance industry. In this study, a parallel cascade combining aryl alcohol oxidase from Pleurotus eryngii (PeAAOx) and unspecific peroxygenase from the basidiomycete Agrocybe aegerita (AaeUPO) to convert aromatic primary alcohols into high-value aromatic aldehydes is proposed. Key influencing factors in the process of enzyme cascade catalysis, such as enzyme dosage, pH and temperature, were investigated. The universality of PeAAOx coupled with AaeUPO cascade catalysis for the synthesis of aromatic aldehyde flavour compounds from aromatic primary alcohols was evaluated. In a partially optimised system (comprising 30 μM PeAAOx, 2 μM AaeUPO at pH 7 and 40 °C) up to 84% conversion of 50 mM veratryl alcohol into veratryl aldehyde was achieved in a self-sufficient aerobic reaction. Promising turnover numbers of 2800 and 21,000 for PeAAOx and AaeUPO, respectively, point towards practical applicability.","AaeUPO; aromatic aldehydes; cascade catalysis; flavour compounds; PeAAOx","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:008210d5-61ec-4b11-8799-855609248ddc","http://resolver.tudelft.nl/uuid:008210d5-61ec-4b11-8799-855609248ddc","Effect of CO2-based binary mixtures on the performance of radial-inflow turbines for the supercritical CO2 cycles","Yang, Yueming (Shandong University); Wang, Xurong (Henan University of Urban Construction); Hooman, K. (TU Delft Process and Energy); Han, Kuihua (Shandong University); Xu, Jinliang (North China Electric Power University); He, Suoying (Shandong University); Qi, Jianhui (Shandong University; North China Electric Power University)","","2023","Recently, the supercritical carbon dioxide (SCO2) power cycle has become a hotspot in the field of energy-efficient utilization. The utilization of additives in the power cycle has been proven to be an effective way to improve the SCO2 power cycle efficiency. As one of the core components of the system, the influence of CO2-based mixtures on turbine performance needs to be further explored. In this study, the preliminary design and three-dimensional numerical simulation of a 500 kW radial-inflow turbine (RIT) for small-scale SCO2 power systems were carried out. Furthermore, the design and off-design performance of high Reynolds number and small size turbine under the change of the CO2-based binary mixture compositions and mixing ratios were studied. Increasing the amount of nitrogen, oxygen, or helium into CO2 has a negative effect on the RIT performance, and the appropriate amount of xenon or krypton can improve the turbine efficiency. Moreover, mixtures with higher krypton additions adapt to higher heat source conditions. The loss of the turbine stage passage shows that a large amount of helium greatly reduces the working fluid density, and the high amount of xenon has a great influence on the dynamic viscosity, which all makes the RIT operation deviate from the steady state. Therefore, the CFD model simulation fails indicating that RIT designed based on pure CO2 may not run smoothly and continuously. The losses in the stage with pure CO2 and CO2–Kr mixture were investigated. The results indicate that the losses originated from the stator cannot be ignored and that the improvement of efficiency is mainly owed to the reduction in clearance losses. There is no doubt that the viewpoints proposed in this paper have significant reference value for the practical application of the SCO2 power cycle using mixtures.","CO-based binary mixture; Numerical simulation; Radial-inflow turbine; Supercritical carbon dioxide; Turbine stage losses","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-06-19","","Process and Energy","","","",""
"uuid:194d20f8-2f2b-4715-ad5b-47b38cdc8be0","http://resolver.tudelft.nl/uuid:194d20f8-2f2b-4715-ad5b-47b38cdc8be0","Numerical investigation on the Thermal-hydraulic performance of the modified channel supercritical CO2 printed circuit heat exchanger","Wang, J. (TU Delft Energy Technology; Wuhan University of Technology; MOST); Yan, Xin ping (Wuhan University of Technology; MOST); Boersma, B.J. (TU Delft Marine and Transport Technology); Lu, Ming jian (Wuhan University of Technology; MOST); Liu, Xiaohua (Wuhan University of Technology; MOST)","","2023","Printed circuit heat exchangers (PCHE) are designed to improve heat recovery and energy saving in supercritical CO2 (S-CO2) power cycles. In the current study, a modified channel PCHE is proposed based on the regular straight channel and a zigzag channel. The thermal–hydraulic performance of four different types of PCHE is numerically investigated and the methods are verified by both experimental and numerical results. The numerical results are presented for a Reynolds number based on the inlet conditions between 5 000 and 25 000. From the numerical results, the local pressure loss and local heat transfer coefficients are analyzed and discussed. Subsequently, the global Nusselt number and Fanning friction coefficients are discussed. It is found that the inserted straight section contributes to uniform flow, resulted in significant pressure loss reduction with a slight decrease in heat transfer. The modified channel can reduce the Fanning friction coefficient by 33.1%-84.7% while the global Nusselt number reduction is about 3.6%-30.3%. This leads to a maximum performance evaluation criterion (PEC) enhancement of 45.9%.","CFD; Heat transfer; Modified channel; Printed circuit heat exchanger; Supercritical carbon dioxide","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","Marine and Transport Technology","Energy Technology","","",""
"uuid:25961f04-7ce7-49e5-a9fa-66af10ad8f26","http://resolver.tudelft.nl/uuid:25961f04-7ce7-49e5-a9fa-66af10ad8f26","Inference algorithms for the useful life of safety instrumented systems under small failure sample data","Mao, Qi (China University of Petroleum (East China)); Wang, Haiqing (China University of Petroleum (East China)); Yang, M. (TU Delft Safety and Security Science); Hu, Jason (Covestro Polymers (China) Co.)","","2023","Safety instrumented systems(SIS) have been widely used in petroleum and chemical plants to detect and respond to dangerous events and prevent them from developing into accidents. The in-service time of SIS does not exceed its useful life is one of the crucial assumptions of IEC functional safety standards. The testing method recommended in the IEC standard is essentially a chi-square testing, where the testing effect is proportional to the sample size and, therefore, not suitable for testing the type of data distribution under small samples. In this paper, a rapid inference method of useful life (RIUL) is proposed to: i) determine whether the distribution type of failure data is exponential under small samples with the help of Anderson-Darling testing, and ii) use the Bayesian sequential testing method for estimating the useful life. The sequential posterior odds ratio testing is introduced to test the equipment failure rate one by one. The proposed RIUL approach is applied to the liquid-level protection circuit of the hot high-pressure separator. The engineering simulation results show that compared with IEC standard methods, the proposed method can be performed with fewer failure data, providing a theoretical basis for reasonable maintenance and replacement of equipment.","Failure rate; Reliability; Safety instrumented systems; Small samples; Useful life","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Safety and Security Science","","",""
"uuid:8abb5654-363a-47b6-b11f-1302c118c07a","http://resolver.tudelft.nl/uuid:8abb5654-363a-47b6-b11f-1302c118c07a","Observation of spin-momentum locked surface states in amorphous Bi2Se3","Corbae, Paul (University of California; Lawrence Berkeley National Laboratory); Ciocys, Samuel (Lawrence Berkeley National Laboratory; University of California); Varjas, D. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; Stockholm University); Kennedy, Ellis (University of California; Lawrence Berkeley National Laboratory); Zeltmann, Steven (University of California; Lawrence Berkeley National Laboratory); Molina-Ruiz, Manel (University of California); Griffin, Sinéad M. (Lawrence Berkeley National Laboratory); Jozwiak, Chris (Lawrence Berkeley National Laboratory); Wang, Lin Wang (Lawrence Berkeley National Laboratory)","","2023","Crystalline symmetries have played a central role in the identification and understanding of quantum materials. Here we investigate whether an amorphous analogue of a well known three-dimensional strong topological insulator has topological properties in the solid state. We show that amorphous Bi2Se3 thin films host a number of two-dimensional surface conduction channels. Our angle-resolved photoemission spectroscopy data are consistent with a dispersive two-dimensional surface state that crosses the bulk gap. Spin-resolved photoemission spectroscopy shows this state has an anti-symmetric spin texture, confirming the existence of spin-momentum locked surface states. We discuss these experimental results in light of theoretical photoemission spectra obtained with an amorphous topological insulator tight-binding model, contrasting it with alternative explanations. The discovery of spin-momentum locked surface states in amorphous materials opens a new avenue to characterize amorphous matter, and triggers the search for an overlooked subset of quantum materials outside of current classification schemes.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","QRD/Kouwenhoven Lab","","",""
"uuid:c9b07a1f-57c3-47eb-84c0-81e51907f50a","http://resolver.tudelft.nl/uuid:c9b07a1f-57c3-47eb-84c0-81e51907f50a","Fabrication sequence optimization for minimizing distortion in multi-axis additive manufacturing","Wang, W. (Dalian University of Technology); van Keulen, A. (TU Delft Mechanical, Maritime and Materials Engineering); Wu, J. (TU Delft Materials and Manufacturing)","","2023","Additive manufacturing of metal parts involves phase transformations and high temperature gradients which lead to uneven thermal expansion and contraction, and, consequently, distortion of the fabricated components. The distortion has a great influence on the structural performance and dimensional accuracy, e.g., for assembly. It is therefore of critical importance to model, predict and, ultimately, reduce distortion. In this paper, we present a computational framework for fabrication sequence optimization to minimize distortion in multi-axis additive manufacturing (e.g., robotic wire arc additive manufacturing), in which the fabrication sequence is not limited to planar layers only. We encode the fabrication sequence by a continuous pseudo-time field, and optimize it using gradient-based numerical optimization. To demonstrate this framework, we adopt a computationally tractable yet reasonably accurate model to mimic the material shrinkage in metal additive manufacturing and thus to predict the distortion of the fabricated components. Numerical studies show that optimized curved layers can reduce distortion by orders of magnitude as compared to their planar counterparts.","Fabrication sequence; Multi-axis additive manufacturing; Process planning; Thermal distortion; Topology optimization; Wire arc additive manufacturing","en","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","","Materials and Manufacturing","","",""
"uuid:fc787c51-4285-4312-ae30-e6e33ec1d94a","http://resolver.tudelft.nl/uuid:fc787c51-4285-4312-ae30-e6e33ec1d94a","A photodecarboxylase from Micractinium conductrix active on medium and short-chain fatty acids","Ma, Yunjian (South China University of Technology; Macau University of Science and Technology); Zhong, Xuanru (South China University of Technology); Wu, Bin (South China University of Technology); Lan, Dongming (South China University of Technology); Zhang, Hao (South China University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Yonghua (South China University of Technology; Guangdong Youmei Institute of Intelligent Bio-manufacturing Co, Foshan)","","2023","Hydrocarbons are essential base chemicals as energy carriers and starting materials for chemical manufacture. So-called fatty acid photodecarboxylases (FAPs) represent interesting catalysts for the conversion of natural fatty acids into hydrocarbons thereby giving access to alkanes from renewable feedstock. Today, however, only few FAPs are known. In the current study we report a new FAP from the marine organism Micractinium conductrix (McFAP). In contrast to currently known FAPs McFAP exhibits high catalytic activity towards short and medium fatty acids. Recombinant expression and basic biochemical characterisation of this new member of the FAP family is reported.","Fatty acids; Heterologous expression; Hydrocarbon biofuel; McFAP; Photodecarboxylase","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-06-10","","","BT/Biocatalysis","","",""
"uuid:54db0f5c-6a06-4e95-b4d9-28a843615aca","http://resolver.tudelft.nl/uuid:54db0f5c-6a06-4e95-b4d9-28a843615aca","Automating building element detection for deconstruction planning and material reuse: A case study","Gordon, Matthew (ETH Zürich; Institute for Advanced Architecture of Catalonia); Batallé Garcia, A. (TU Delft Design & Construction Management); De Wolf, Catherine (ETH Zürich); Sollazzo, Aldo (Institute for Advanced Architecture of Catalonia); Dubor, Alexandre (Institute for Advanced Architecture of Catalonia); Wang, T. (TU Delft Design & Construction Management)","","2023","To address the need for a shift from a linear to a circular economy in the built environment, this paper develops a semi-automated assistive process for planning building material deconstruction for reuse using sensing and scanning, Scan-to-BIM, and computer vision techniques. These methods are applied and tested in a real-world case study in Geneva, Switzerland, with a focus on reconstruction and recovery analysis for floor beam systems. First, accessible sensing and scanning tools, such as mobile photography and smartphone-based consumer-grade Lidar devices, are used to capture imagery and other data from an active demolition site. Then, photogrammetry and point cloud data analysis are performed to construct a 3D BIM model of relevant areas. The structural relationships between reconstructed BIM elements are evaluated to score the feasibility for recovery of each element. This study illustrates what is feasible and where further development is necessary for automating building material reuse planning at scale to increase the uptake of circular economy practices in the construction sector.","BIM; Building deconstruction; Circularity; Digitalization; Lidar; Material reuse; Photogrammetry; Point cloud","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:95d9e5ba-6bac-4dc7-a864-1e2225b4871e","http://resolver.tudelft.nl/uuid:95d9e5ba-6bac-4dc7-a864-1e2225b4871e","Risk consequence assessment of dam breach in cascade reservoirs considering risk transmission and superposition","Wang, Te (Zhengzhou University); Li, Zongkun (Zhengzhou University); Ge, W. (TU Delft Safety and Security Science; Zhengzhou University; Yellow River Engineering Consulting Co); zhang, Z.H. (Zhengzhou University); Zhang, Yadong (Zhengzhou University); Sun, Heqiang (Zhengzhou University); Jiao, Yutie (Zhengzhou University)","","2023","Compared with a single reservoir, the risk in cascade reservoirs has the transmission and superposition effect, which increases the complexity of its risk consequence assessment. In view of this problem, the direct consequence (DC) and potential consequence (PC) were defined as two parts of the dam breach risk consequence of cascade reservoirs. The upstream dam-break flood inundation line and the downstream reservoir land acquisition line were taken as the upper and lower boundaries of the assessment space, which made the risk consequence assessment more intuitive and further improved its scientificity and practicability. Subsequently, the conditional probability of downstream dam breach under the upstream dam-break flood was determined to quantify the risk transmission and superposition. On this basis, the relevant concepts and formulas for calculating the dam breach risk consequence in cascade reservoirs were proposed. Taking five cascade reservoirs as examples, the risk consequences of each cascade dam breach were evaluated. The results show that the proposed method is effective in assessing the risk consequence of dam breach in cascade reservoirs and is more in line with the connotation of dam risk management, which can provide reference for the design and risk control of cascade reservoirs.","Cascade reservoirs; Dam breach; Loss; Risk management; Risk transmission","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Safety and Security Science","","",""
"uuid:c487fe21-f61e-4544-ad12-5fe656e48d2a","http://resolver.tudelft.nl/uuid:c487fe21-f61e-4544-ad12-5fe656e48d2a","Sandwich-like heterostructured nanomaterials immobilized laccase for the degradation of phenolic pollutants and boosted enzyme stability","Li, Mengyu (Zhengzhou University); Bai, Yahan (Zhengzhou University); Zhuang, Wei (Zhengzhou University; Nanjing Tech University); Liu, Jinle (Zhengzhou University); Wang, Zhi (Zhengzhou University); Rao, Yuan (Zhengzhou University); Li, Mengran (TU Delft ChemE/Materials for Energy Conversion and Storage); Ying, Hanjie (Nanjing Tech University); Ouyang, Pingkai (Nanjing Tech University)","","2023","A novel magnetic 2D/2D heterogeneous structure MXene@NiFe-LDH@Fe3O4 was prepared for immobilization of laccase. In this work, two-dimensional MXene nanosheets with abundant surface functional groups were heterogeneously assembled with layered double hydroxide (LDH) by in situ co-precipitation method, and magnetic nanoparticle Fe3O4 with excellent biocompatibility and rapid separation of materials and substrates was introduced subsequently, and then silane coupling agent was coated on the surface of MXene@NiFe-LDH@Fe3O4. The functionalized MXene@NiFe-LDH@Fe3O4 was employed as a carrier to immobilize laccase from Trametes-Versicolor. The enzyme loading of the nanocomposite material is as high as 167.9 mg/g. Compared with free enzymes, the immobilized laccase showed a notable improvement in stability in a wider range of pHs (2.0–8.0), temperatures (25–60 °C), and organic solvent concentration (1–5 M). The reusability study suggested that after 7 cycles of repeated catalysis, the degradation efficiency could reach 55.5% for 2,4-dichlorophenol, 92.1% for bisphenol A and70.9% for pyrocatechol. The results provide a new carrier preparation strategy for the efficient immobilization of laccase.","2D nanomaterials; Heterogeneous assembly; Immobilized laccase; Simulated industrial wastewater","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:7a5ae775-e1e7-421d-9528-3785f2983af0","http://resolver.tudelft.nl/uuid:7a5ae775-e1e7-421d-9528-3785f2983af0","Elucidation of the Charging Mechanisms and the Coupled Structural–Mechanical Behavior of Ti3C2Tx (MXenes) Electrodes by In Situ Techniques","Bergman, Gil (Bar-Ilan University); Ballas, Elad (Bar-Ilan University); Gao, Qiang (Oak Ridge National Laboratory); Nimkar, Amey (Bar-Ilan University); Gavriel, Bar (Bar-Ilan University); Levi, Mikhael D. (Bar-Ilan University); Sharon, Daniel (The Hebrew University of Jerusalem); Malchik, Fyodor (al-Farabi Kazakh National University, Almaty); Wang, Xuehang (TU Delft RST/Storage of Electrochemical Energy)","","2023","The discovery of the Ti3C2Tx compounds (MXenes) a decade ago opened new research directions and valuable opportunities for high-rate energy storage applications. The unique ability of the MXenes to host various mono- and multivalent cations and their high stability in different electrolyte environments including aqueous, organic, and ionic liquid solutions, promoted the rapid development of advanced MXene-based electrodes for a large variety of applications. Unlike the vast majority of typical intercalation compounds, the electrochemical performance of MXene electrodes is strongly influenced by the presence of co-inserted solvent molecules, which cannot be detected by conventional current/potential electrochemical measurements. Furthermore, the electrochemical insertion of ions into MXene interspaces results in strong coupling with the intercalation-induced structural, dimensional, and viscoelastic changes in the polarized MXene electrodes. To shed light on the charging mechanisms of MXene systems and their associated phenomena, the use of a large variety of real-time monitoring techniques has been proposed in recent years. This review summarizes the most essential findings related to the charging mechanism of Ti3C2Tx electrodes and their potential induced structural and mechanical phenomena obtained by in situ investigations.","in situ techniques; MXenes; pseudo-capacitors; super-capacitors; Ti C T","en","review","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:3a2eb469-6a98-42fd-8f7a-b83c25b2d8e2","http://resolver.tudelft.nl/uuid:3a2eb469-6a98-42fd-8f7a-b83c25b2d8e2","Forward and reverse logistics for circular economy in construction: A systematic literature review","Ding, L. (TU Delft Design & Construction Management); Wang, T. (TU Delft Design & Construction Management); Chan, P.W.C. (TU Delft Design & Construction Management)","","2023","To close the loop for the circular economy (CE) transition in the construction industry, forward logistics (FL) and reverse logistics (RL), as enabling operations for CE, are important topics to be addressed. However, current research mainly focuses on either FL or RL, with a lack of synthesis that presents an overview of the bi-directional logistics system integrating FL and RL and related mechanisms to close the loop. This review, therefore, explores the current cases of FL and RL in the construction arena through a systematic literature review (SLR) process. A review framework to synthesize and compare both FL and RL operations in various phases of the construction project life cycle (CPLC) has been established for this purpose. The phases include - in FL: design, manufacturing, construction, and operations; and in RL: deconstruction, product reuse, waste distribution, and material reprocessing. The review concludes that while similar methods and CE strategies are used in FL and RL, RL operations require more integration between supply chain actors to close the loop for CE in construction. The findings also indicate that more lateral integration between FL and RL phases beyond the life cycle and industrial boundaries is necessary for CE-driven construction projects, instead of only direct vertical integration with up- and down-stream partners. This review proposes a new conceptual framework of circular logistics integration (CLI) that consists of channel creation, network integration, and inventory management to guide and inspire future research in tackling the systematic barriers that hinder materials and resource flow from RL to FL in construction life cycles.","Circular economy; Circular logistics integration; Conceptual framework; Construction industry; Construction project life cycle phases; Logistics; Supply chain actors","en","review","","","","","","","","","","","Design & Construction Management","","",""
"uuid:3f8cfafc-be8b-4bfe-b683-e0db00d2bfeb","http://resolver.tudelft.nl/uuid:3f8cfafc-be8b-4bfe-b683-e0db00d2bfeb","粉末床熔融的多材料铺粉过程中粉末扩散的数值研究","Wang, L. (TU Delft Resources & Recycling); Li, Erlei (Monash University); Zhou, Zongyan (Monash University; University of Science and Technology Beijing); Zhang, Baicheng (University of Science and Technology Beijing); Yu, Aibing (Monash University)","","2023","Powder bed fusion additive manufacturing has been applied to the fabrication of functionally graded materials. A new design that allows the material composition to change along the direction perpendicular to the powder spreading has been reported in the literature. Based on this design, this work examines the quality of the graded spread powder layer with two powders, which have a large difference of density. The results reveal that during the spreading of graded powders, the volume of particles on the heavy powder side is deposited less than that on the light powder side, indicating that heavy particles diffuse to the light powder side. This diffusion is affected by the spreading speed, but not much by the layer gap. Large spreading speed causes more significant deviation. The results also show that particle size affects diffusion, indicating that decreasing the particle size of the heavy powder may be a solution to reduce diffusion. [Figure not available: see fulltext.]","DEM simulation; Functionally graded material; Powder bed fusion additive manufacturing; Powder spreading","zh","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-09","","","Resources & Recycling","","",""
"uuid:7318bf60-e5c7-47d8-8c3d-14c4685638e5","http://resolver.tudelft.nl/uuid:7318bf60-e5c7-47d8-8c3d-14c4685638e5","Assessing the Mass Concentration of Microplastics and Nanoplastics in Wastewater Treatment Plants by Pyrolysis Gas Chromatography-Mass Spectrometry","Xu, Yanghui (TU Delft Water Management; TU Delft Sanitary Engineering; Chinese Academy of Sciences); Ou, Q. (TU Delft Water Management; TU Delft Sanitary Engineering; Chinese Academy of Sciences); Wang, Xintu (Chinese Academy of Sciences; Guilin University of Technology); Hou, Feng (China Water Environmental Group Limited); Li, Peng (China Water Environmental Group Limited); van der Hoek, J.P. (TU Delft Water Management; TU Delft Sanitary Engineering; Waternet); Liu, G. (TU Delft Water Management; TU Delft Space Systems Egineering; Chinese Academy of Sciences; University of Chinese Academy of Sciences)","","2023","The level of microplastics (MPs) in wastewater treatment plants (WWTPs) has been well evaluated by the particle number, while the mass concentration of MPs and especially nanoplastics (NPs) remains unclear. In this study, pyrolysis gas chromatography-mass spectrometry was used to determine the mass concentrations of MPs and NPs with different size ranges (0.01-1, 1-50, and 50-1000 μm) across the whole treatment schemes in two WWTPs. The mass concentrations of total MPs and NPs decreased from 26.23 and 11.28 μg/L in the influent to 1.75 and 0.71 μg/L in the effluent, with removal rates of 93.3 and 93.7% in plants A and B, respectively. The proportions of NPs (0.01-1 μm) were 12.0-17.9 and 5.6-19.5% in plants A and B, respectively, and the removal efficiency of NPs was lower than that of MPs (>1 μm). Based on annual wastewater effluent discharge, it is estimated that about 0.321 and 0.052 tons of MPs and NPs were released into the river each year. Overall, this study investigated the mass concentration of MPs and NPs with a wide size range of 0.01-1000 μm in wastewater, which provided valuable information regarding the pollution level and distribution characteristics of MPs, especially NPs, in WWTPs.","mass concentration; microplastics; nanoplastics; Py-GC/MS; WWTPs","en","journal article","","","","","","","","","","Water Management","Sanitary Engineering","","",""
"uuid:a648536f-c3b1-40a1-9137-4c5510a21344","http://resolver.tudelft.nl/uuid:a648536f-c3b1-40a1-9137-4c5510a21344","Elevated physical weathering exceeds chemical weathering of clays during the Paleocene-Eocene Thermal Maximum in the continental Bighorn Basin (Wyoming, USA)","Ji, Kaipeng (China University of Geosciences, Wuhan); Wang, C. (TU Delft Applied Geology; China University of Geosciences, Wuhan); Hong, Hanlie (China University of Geosciences, Wuhan); Yin, Ke (China University of Geosciences, Wuhan); Zhao, Chenlei (China University of Geosciences, Wuhan); Prins, Maarten (Vrije Universiteit Amsterdam); Lourens, Lucas J. (Universiteit Utrecht); Gingerich, Philip D. (University of Michigan); Abels, H.A. (TU Delft Applied Geology)","","2023","The Paleocene-Eocene Thermal Maximum (PETM) global warming event at ∼56 million years before present changed catchment weathering and erosion. Increased chemical weathering of silicate minerals is thought to be an important process removing CO2 from the atmosphere. However, changes in clay mineralogy can often be explained by enhanced erosion of catchment laterites during the event. Here, we investigate chemical and physical weathering and erosive flux changes through the PETM interval in the Bighorn Basin, Wyoming, a Laramide foreland basin, in a proximal continental-interior alluvial setting. These show an increase of detrital smectite with a lag time of 20-kyr after the main onset the PETM. The smectite increase continued for at least 50-kyr after the event. In-situ, post-depositional pedogenic clay mineral formation is similar between pre-PETM and PETM soil profiles, despite large macroscopic differences between soils that formed before and during the event. Drier, hotter summers during the PETM probably caused decreased vegetation cover that, in concert with more frequent and heavier rainstorms, intensified the erosion of smectite-rich Cretaceous bentonites on the margins of the catchment, which exceeded changes in chemical weathering within the catchment. The lagged response in reaching full PETM clay mineral values can be explained by the time required for upstream sediment to reach the catchment basin floodplain. The prolonged nature of smectite enhancement after the PETM event may again relate to signal propagation times that are now even longer due to lower fluvial recycling rates. Our results indicate that chemical weathering changes were probably superceded by enhanced physical weathering and clay-mineral transport from basin margins at this continental-interior study site.","Continental weathering; Paleocene-Eocene Thermal Maximum; Paleoclimatology; Polecat Bench; Smectite","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-08-13","","","Applied Geology","","",""
"uuid:b95cd7ad-3ca6-470a-8c3c-8f6f90006850","http://resolver.tudelft.nl/uuid:b95cd7ad-3ca6-470a-8c3c-8f6f90006850","4DEnVar-based inversion system for ammonia emission estimation in China through assimilating IASI ammonia retrievals","Jin, J. (TU Delft Mathematical Physics; Nanjing University of Information Sciences and Technology); Fang, Li (Nanjing University of Information Sciences and Technology); Li, Baojie (Nanjing University of Information Sciences and Technology); Liao, Hong (Nanjing University of Information Sciences and Technology); Wang, Ye (Nanjing University of Information Sciences and Technology); Han, Wei (China Meteorological Administration); Li, Ke (Nanjing University of Information Sciences and Technology); Pang, Mijie (Nanjing University of Information Sciences and Technology); Wu, Xingyi (Nanjing University of Information Sciences and Technology); Lin, H.X. (TU Delft Mathematical Physics; Universiteit Leiden)","","2023","Atmospheric ammonia has been hazardous to the environment and human health for decades. Current inventories are usually constructed in a bottom-up manner and subject to uncertainties and incapable of reproducing the spatiotemporal characteristics of ammonia emission. Satellite measurements, for example, Infrared Atmospheric Sounder Interferometer (IASI) and Cross-Track Infrared Sounder, which provide global coverage of ammonia distribution, have gained popularity in ammonia emission estimation through data assimilation methods. However, satellite-based emission inversion studies on China are limited. In this study, we propose a four-dimensional ensemble variational-based ammonia emission inversion system to optimize ammonia emissions in China. It was developed by assimilating the IASI ammonia retrievals onboard Meteorological Operational satellite A and B into a chemical transport model Goddard Earth Observing System Chemical model (GEOS-Chem). Monthly inversion experiments were conducted in April, July, and October 2016 to test the performance. The inversion result indicated that the prior inventory from the MEIC model captured ammonia spreads in general; however, it heterogeneously underrated the emission intensity. The increments obtained in the assimilation were as high as 50% in North, East, and Northwest China. The posterior emission inventory presented a regional emission flux consistent with relevant studies. Driven by the optimized source estimate, GEOS-Chem provides superior results than using the prior in the evaluation of the assimilated IASI retrievals and the surface ammonia concentration measured by the ground-based Ammonia Monitoring Network in China.","atmospheric ammonia; emission inversion; IASI","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:4dbe0d27-cbe3-439c-bec1-6922e86cd711","http://resolver.tudelft.nl/uuid:4dbe0d27-cbe3-439c-bec1-6922e86cd711","A biomimetic red blood cell inspired encapsulation design for advanced hydrate-based carbon capture","Zhang, Yuxuan (Australian National University); Zhai, Xiaoqiang (Shanghai Jiao Tong University); Zhang, Fengyuan (Australian National University); Zhang, Zhongbin (Nanjing Normal University); Hooman, K. (TU Delft Process and Energy); Zhang, Hai (Shanghai Jiao Tong University); Wang, Xiaolin (Australian National University)","","2023","Enhancing gas-liquid mass transfer is key to promote gas hydrate formation kinetics. Encapsulation of CO2 hydrate is expected to dramatically increase gas-liquid contact to enhance mass transfer. However, gas hydrate encapsulation has never been proposed as the technical issues of gas permeation through capsule shells have never been addressed. In this work, based on the principles of biomimetics, we proposed a novel red blood cell (RBC) inspired carbon capture capsule to promote CO2 hydrate formation kinetics. An experimentally validated model is established to compare the carbon capture performance in an RBC-shaped and a spherical capsule. It is revealed that the gas uptake efficiency of the RBC-shaped capsule is 143% higher than that of the spherical one. The effect of initial pressure and capsule size on CO2 hydrate formation kinetics is also investigated. Furthermore, the structure of RBC is optimised and it is found the average amount of hydrate formation per surface area achieves a peak when the ratio of the height at the centre to the width of the ring is between 0.128 and 0.160, which is close to that of real RBCs in human bodies. This work enables the informed design of hydrate-based carbon capture units with high gas uptake efficiency.","Heat and mass transfer; Hydrate formation kinetics; Hydrate-based carbon capture; Red blood cell","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-08-20","","Process and Energy","","","",""
"uuid:122f5eae-3337-435e-a593-6b3bb6c13c01","http://resolver.tudelft.nl/uuid:122f5eae-3337-435e-a593-6b3bb6c13c01","Developing a long-term management strategy to prepare the Dutch coast for the future, editorial of the VSI future Dutch coast","Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); Lodder, Q.J. (TU Delft Policy Analysis; TU Delft Coastal Engineering; GE Global Research - Europe); van der Spek, A.J.F. (TU Delft Coastal Engineering; Deltares; Universiteit Utrecht); Slinger, J (TU Delft Policy Analysis); Hoekstra, Piet (Universiteit Utrecht; Wadden Academy)","","2023","","Adaptation strategy; Sea level rise; Sediment budget; Shoreface dynamics; Tidal inlets; ‘Research for policy’ cycle","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:9d0ee92a-4cd5-47f7-86fd-7eb9a39b2a1b","http://resolver.tudelft.nl/uuid:9d0ee92a-4cd5-47f7-86fd-7eb9a39b2a1b","Microscopic Traffic Modeling Inside Intersections: Interactions Between Drivers","Zhao, J. (TU Delft Transport and Planning; University of Shanghai for Science and Technology); Knoop, V.L. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning; Technische Universität Dresden)","","2023","Microscopic traffic flow models enable predictions of traffic operations, which allows traffic engineers to assess the efficiency and safety effects of roadway designs. Modeling vehicle trajectories inside intersections is challenging because there is an infinite number of possible paths in a two-dimensional space, and drivers can simultaneously adapt their speeds as well. To date, human driver models for simultaneous longitudinal and lateral vehicle control based on the infrastructure characteristics and interactions with other drivers inside an intersection are still lacking. The contribution of this paper is threefold. First, it proposes an integrated microscopic traffic flow model to describe human-driven vehicle maneuvers under interactions. Drivers plan their heading and acceleration in the predicted future to minimize costs representing undesirable situations. The model works with a joint optimization for an interaction cost term. The weights associated with the interaction cost reflect how selfish or altruistic drivers are. Second, the proposed model endogenously gives the order of vehicles in case of crossing paths. Third, the paper develops a clustered validation method for microscopic traffic flow models with interacting vehicles, which account for interdriver variations. Results show that the model can accurately describe vehicle passing orders of interacting maneuvers, paths, and speeds against empirical data. The model can be applied to assess various intersection designs.","driver interactions; intersections; optimal control; traffic flow model; vehicular trajectory","en","journal article","","","","","","","","","","Transport and Planning","Transport and Planning","","",""
"uuid:0beed756-9307-4c12-bc25-f7f5148ae3cc","http://resolver.tudelft.nl/uuid:0beed756-9307-4c12-bc25-f7f5148ae3cc","Existence of solutions to the generalized periodic fractional boundary value problem","Fečkan, Michal (Comenius University; Mathematical Institute of Slovak Academy of Sciences); Marynets, K. (TU Delft Mathematical Physics); Wang, J. (TU Delft Mechanical, Maritime and Materials Engineering; Guizhou University)","","2023","We study a boundary value problem for a Caputo-type fractional differential equation subjected to periodic boundary conditions. For an auxiliary problem with the simplified right-hand side, we explicitly construct its unique solution. In addition, based on the theory of the topological index, we prove existence of at least one solution to the original problem.","existence of solutions; fractional boundary value problem; periodic boundary conditions; topological index","en","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","","Mathematical Physics","","",""
"uuid:ea3f1c52-83ab-4edb-8987-4e9e1d4abbb8","http://resolver.tudelft.nl/uuid:ea3f1c52-83ab-4edb-8987-4e9e1d4abbb8","Realization of a minimal Kitaev chain in coupled quantum dots","Dvir, T. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, Guanzhong (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); van Loo, N. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Liu, C. (TU Delft QRD/Wimmer Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Mazur, G.P. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Bordin, A. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); ten Haaf, S.L.D. (TU Delft Communication QuTech; TU Delft QRD/Goswami Lab; Kavli institute of nanoscience Delft); van Driel, D. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Zatelli, F. (TU Delft Applied Sciences; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Li, X. (TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Malinowski, F.K. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Gazibegovic, Sasa (Eindhoven University of Technology); Badawy, G.H.A. (Eindhoven University of Technology); Bakkers, Erik P.A.M. (Eindhoven University of Technology); Wimmer, M.T. (TU Delft QN/Wimmer Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)","","2023","Majorana bound states constitute one of the simplest examples of emergent non-Abelian excitations in condensed matter physics. A toy model proposed by Kitaev shows that such states can arise at the ends of a spinless p-wave superconducting chain1. Practical proposals for its realization2,3 require coupling neighbouring quantum dots (QDs) in a chain through both electron tunnelling and crossed Andreev reflection4. Although both processes have been observed in semiconducting nanowires and carbon nanotubes5–8, crossed-Andreev interaction was neither easily tunable nor strong enough to induce coherent hybridization of dot states. Here we demonstrate the simultaneous presence of all necessary ingredients for an artificial Kitaev chain: two spin-polarized QDs in an InSb nanowire strongly coupled by both elastic co-tunnelling (ECT) and crossed Andreev reflection (CAR). We fine-tune this system to a sweet spot where a pair of poor man’s Majorana states is predicted to appear. At this sweet spot, the transport characteristics satisfy the theoretical predictions for such a system, including pairwise correlation, zero charge and stability against local perturbations. Although the simple system presented here can be scaled to simulate a full Kitaev chain with an emergent topological order, it can also be used imminently to explore relevant physics related to non-Abelian anyons.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-08-15","Applied Sciences","","QRD/Kouwenhoven Lab","","",""
"uuid:69c16d7a-23da-49fc-a8e4-80b3a9e58ced","http://resolver.tudelft.nl/uuid:69c16d7a-23da-49fc-a8e4-80b3a9e58ced","Interplay Between Friction and Cohesion: A Spectrum of Retrogressive Slope Failure","Wang, Bin (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Wang, Di (Chinese Academy of Sciences); Hicks, M.A. (TU Delft Geo-engineering); Feng, Xia Ting (Northeastern University)","","2023","Retrogressive failures occur in slopes consisting of sensitive materials such as snow or quick clay. They can be triggered by a small disturbance at the slope toe, but can cause propagated failure spreading miles away. Understanding the physical mechanism and predicting the retrogressive failure process are particularly important. Previous studies have discussed the failure criteria, the soil properties or the method of numerical modeling of retrogressive slope failure. However, little attention has been paid to the microscopic failure mechanism, especially relating to various possible failure patterns. In this study, multiscale modeling is incorporated to study the physical mechanism of different retrogressive failure patterns, including earth flow, flowslide and spread failure, within a unified framework. Utilizing multiscale analysis, we found that earth flow failure is related to the shear failure of granular materials. In contrast, the development of macroscopic shear bands is accompanied by tensile failure. As shear and tension failures are typical failure mechanisms of frictional and cohesive materials, it is deduced that friction and cohesion effects play key roles in different retrogressive failure patterns. Therefore, the distributions of attractive and repulsive contact forces are explored and a novel parameter η is proposed to quantify the interplay between friction and cohesion. Further analysis proves that η can capture the effect of friction and cohesion and distinguish different retrogressive failure patterns. Finally, a spectrum of retrogressive failures for a granular slope is established, in which the failure mechanism is explained by the changeable dominant effect, that is, frictional or cohesive in soil.","cohesion; friction; multiscale modeling; retrogressive slope failure","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-30","","","Geo-engineering","","",""
"uuid:2cd2f7a0-7f1a-47da-84c6-d627b21e5502","http://resolver.tudelft.nl/uuid:2cd2f7a0-7f1a-47da-84c6-d627b21e5502","GlobalMatch: Registration of forest terrestrial point clouds by global matching of relative stem positions","Wang, Xufei (Tongji University); Yang, Z. (TU Delft Urban Data Science; Tongji University); Cheng, Xiaojun (Tongji University); Stoter, J.E. (TU Delft Urban Data Science); Xu, Wenbing (Zhejiang Agriculture and Forestry University); Wu, Zhenlun (Big Data Development Administration of Yichun); Nan, L. (TU Delft Urban Data Science)","","2023","Registering point clouds of forest environments is an essential prerequisite for LiDAR applications in precision forestry. State-of-the-art methods for forest point cloud registration require the extraction of individual tree attributes, and they have an efficiency bottleneck when dealing with point clouds of real-world forests with dense trees. We propose an automatic, robust, and efficient method for the registration of forest point clouds. Our approach first locates tree stems from raw point clouds and then matches the stems based on their relative spatial relationship to determine the registration transformation. The algorithm requires no extra individual tree attributes and has quadratic complexity to the number of trees in the environment, allowing it to align point clouds of large forest environments. Extensive experiments on forest terrestrial point clouds have revealed that our method inherits the effectiveness and robustness of the stem-based registration strategy while exceedingly increasing its efficiency. Besides, we introduce a new benchmark dataset that complements the very few existing open datasets for the development and evaluation of registration methods for forest point clouds. The source code of our method and the dataset are available at https://github.com/zexinyang/GlobalMatch.","Dataset; Forest; Laser scanning; Point cloud; Registration","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-08-01","","","Urban Data Science","","",""
"uuid:8dc781c8-d4bb-425a-abb6-87d6acb10164","http://resolver.tudelft.nl/uuid:8dc781c8-d4bb-425a-abb6-87d6acb10164","The Coastal Genesis 2 research programme: Outputs, Outcomes and Impact","Lodder, Q.J. (TU Delft Policy Analysis; Rijkswaterstaat); Slinger, J (TU Delft Policy Analysis; Rhodes University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); van der Spek, A. J.F. (Deltares); Hijma, M. P. (Deltares); Taal, M. (Deltares); van Gelder-Maas, C. (Rijkswaterstaat); de Looff, H. (Rijkswaterstaat); Litjens, J. (Rijkswaterstaat); Schipper, C. A. (Rijkswaterstaat); Löffler, M. (Bureau Landwijzer); Nolte, A. J. (Deltares); van Oeveren, C. (Deltares); van der Werf, J. J. (Deltares; University of Twente); Grasmeijer, B. T. (Deltares); Elias, E. P.L. (Deltares); Holzhauer, H. (Rijkswaterstaat); Tonnon, P. K. (Deltares)","","2023","The long-term sediment demand of the Dutch coast is integral to the current Dutch Coastal Flood and Erosion Risk Management policy. The Coastal Genesis 2 research programme was initiated to address the sustainability of this policy under sea level rise by focusing on key uncertainties in the conceptual model of the sediment demand of the Dutch coast. The substantive scientific contributions of the Coastal Genesis 2 research programme are analysed in this paper by applying an output-outcome-impact framework. The direct outputs of the programme are categorised in terms of the knowledge types of a 5-element framework, namely measurement data, simulation models, system understanding, conceptual models, and policy and practice. The research outcomes arise from the interactions of these knowledge types. Our analysis of these outcomes highlights that synthesising new scientific insights into shared conceptual models is critical to achieving impact in policy and practice. In the Dutch situation, a new shared conceptual model of the long-term sediment demand enabled the development of four potential nourishment strategies aiming to meet the strategic goals of the Coastal Flood and Erosion Risk Management policy on a timescale up to 20 years. In 2021, the Minister of Infrastructure and Water Management officially articulated her intention to adopt the advised nourishment strategy from 2024 onwards. This represents a lasting impact of the Coastal Genesis 2 research programme in policy and practice. Further, the insight regarding the pivotal role of shared conceptual models as intermediary between science, policy and practice may prove useful in the design of future research programmes aiming to influence policy.","Conceptual model; Dutch Coastal policy development; Flood and Erosion risk; Nourishment strategy; Policy impact; Sediment budget","en","journal article","","","","","","","","","","","Policy Analysis","","",""
"uuid:028a0f1d-691c-4864-a6d3-1acbf9457acf","http://resolver.tudelft.nl/uuid:028a0f1d-691c-4864-a6d3-1acbf9457acf","A Plant-inspired Light Transducer for High-performance Near-infrared Light Mediated Gas Sensing","Liang, Hongping (South China Normal University; Huizhou University); Guo, Xin (South China Normal University); Guo, Lanpeng (South China Normal University); Liu, Siying (South China Normal University); Zhan, Qiuqiang (South China Normal University); Yang, Haihong (The First Affiliated Hospital of Guangzhou Medical University); Li, Hao (South China Normal University); de Rooij, Nicolaas Frans (South China Normal University); Lee, Yi Kuen (The Hong Kong University of Science and Technology); French, P.J. (TU Delft Bio-Electronics); Wang, Yao (South China Normal University); Zhou, Guofu (South China Normal University)","","2023","Constructing near-infrared light (NIR) light-enhanced room temperature gas sensors is becoming more promising for practical application. In this study, learning from the structure and photosynthetic process of chlorophyll thylakoid membranes in plants, the first “Thylakoid membrane” structural formaldehyde (HCHO) sensor is constructed by matching the upconversion emission of the lanthanide-doped upconversion nanoparticles (UCNPs) and the UV–vis adsorption of the as-prepared nanocomposites. The NIR-mediated sensor exhibits excellent performances, including ultra-high response (Ra / Rg = 2.22, 1 ppm), low practical limit of detection (50 ppb), reliable repeatability, high selectivity, and broadband spectral response. The practicality of the NIR-mediated gas sensor is confirmed through the remote and external stimulation test. A study of sensing mechanism demonstrates that it is the UCNPs-based light transducer produces more light-induced oxygen species for gas response in the process of non-radiative/radiative energy transfer, playing a key role in significantly improving the sensing properties of the sensor. The universality of NIR-mediated gas sensors based on UCNPs is verified using ZnO, In2O3, and SnO2 systems. This work paves a way for fabricating high-performance NIR-mediated gas sensors and will expand the application fields of NIR light.","gas sensors; light transducers; NIR-mediation; thylakoid membranes; upconversion nanoparticles","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-04","","","Bio-Electronics","","",""
"uuid:1ad6c54e-35b6-4479-b756-a3e6040d5cb4","http://resolver.tudelft.nl/uuid:1ad6c54e-35b6-4479-b756-a3e6040d5cb4","Modeling and Efficient Passenger-Oriented Control for Urban Rail Transit Networks","Liu, X. (TU Delft Team Bart De Schutter); Dabiri, A. (TU Delft Team Azita Dabiri); Wang, Yihui (Beijing Jiaotong University); De Schutter, B.H.K. (TU Delft Delft Center for Systems and Control)","","2023","Real-time timetable scheduling is an effective way to improve passenger satisfaction and to reduce operational costs in urban rail transit networks. In this paper, a novel passenger-oriented network model is developed for real-time timetable scheduling that can model time-dependent passenger origin-destination demands with consideration of a balanced trade-off between model accuracy and computation speed. Then, a model predictive control (MPC) approach is proposed for the timetable scheduling problem based on the developed model. The resulting MPC optimization problem is a nonlinear non-convex problem. In this context, the online computational complexity becomes the main issue for the real-time feasibility of MPC. To reduce the online computational complexity, the MPC optimization problem is therefore reformulated into a mixed-integer linear programming (MILP) problem. The resulting MILP problem is exactly equivalent to the original MPC optimization problem and can be solved very efficiently by existing MILP solvers, so that we can obtain the solution very fast and realize real-time timetable scheduling. Numerical experiments based on a part of Beijing subway network show the effectiveness and efficiency of the developed model and the MILP-based MPC method.","Model predictive control; real-time timetable scheduling; time-dependent passenger origin-destination demand; urban rail transit","en","journal article","","","","","","","","","","Delft Center for Systems and Control","Team Bart De Schutter","","",""
"uuid:72a43dd5-0181-49d3-86e1-bb1af7d4f865","http://resolver.tudelft.nl/uuid:72a43dd5-0181-49d3-86e1-bb1af7d4f865","Coherent Control of a Nuclear Spin via Interactions with a Rare-Earth Ion in the Solid State","Uysal, Mehmet T. (Princeton University); Raha, Mouktik (Princeton University); Chen, Songtao (Princeton University); Phenicie, Christopher M. (Princeton University); Ourari, Salim (Princeton University); Wang, Mengen (University of California); Van De Walle, Chris G. (University of California); Dobrovitski, V.V. (TU Delft QID/Dobrovitski Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Thompson, Jeff D. (Princeton University)","","2023","Individually addressed Er3+ ions in solid-state hosts are promising resources for quantum repeaters, because of their direct emission in the telecom band and their compatibility with silicon photonic devices. While the Er3+ electron spin provides a spin-photon interface, ancilla nuclear spins could enable multiqubit registers with longer storage times. In this work, we demonstrate coherent coupling between the electron spin of a single Er3+ ion and a single I=1/2 nuclear spin in the solid-state host crystal, which is a fortuitously located proton (1H). We control the nuclear spin using dynamical-decoupling sequences applied to the electron spin, implementing one- and two-qubit gate operations. Crucially, the nuclear spin coherence time exceeds the electron coherence time by several orders of magnitude, because of its smaller magnetic moment. These results provide a path toward combining long-lived nuclear spin quantum registers with telecom-wavelength emitters for long-distance quantum repeaters.","","en","journal article","","","","","","","","","","","QID/Dobrovitski Group","","",""
"uuid:f004ee9f-575d-409e-8602-8aa32a97dd95","http://resolver.tudelft.nl/uuid:f004ee9f-575d-409e-8602-8aa32a97dd95","Plastic waste discharge to the global ocean constrained by seawater observations","Zhang, Yanxu (Nanjing University); Wu, Peipei (Nanjing University); Xu, Ruochong (Nanjing University); Wang, Xuantong (Nanjing University); Lei, Lili (Nanjing University); Schartup, Amina T. (University of California); Peng, Yiming (Nanjing University); Pang, Qiaotong (Nanjing University); Luijendijk, Arjen (TU Delft Coastal Engineering; Deltares)","","2023","Marine plastic pollution poses a potential threat to the ecosystem, but the sources and their magnitudes remain largely unclear. Existing bottom-up emission inventories vary among studies for two to three orders of magnitudes (OMs). Here, we adopt a top-down approach that uses observed dataset of sea surface plastic concentrations and an ensemble of ocean transport models to reduce the uncertainty of global plastic discharge. The optimal estimation of plastic emissions in this study varies about 1.5 OMs: 0.70 (0.13–3.8 as a 95% confidence interval) million metric tons yr−1 at the present day. We find that the variability of surface plastic abundance caused by different emission inventories is higher than that caused by model parameters. We suggest that more accurate emission inventories, more data for the abundance in the seawater and other compartments, and more accurate model parameters are required to further reduce the uncertainty of our estimate.","","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:f19c54bb-f3a0-41f5-af10-7930f1caebab","http://resolver.tudelft.nl/uuid:f19c54bb-f3a0-41f5-af10-7930f1caebab","Pool fire burning characteristics and risks under wind-free conditions: State-of-the-art","Guo, Youwei (Southwest Petroleum University); Xiao, Guoqing (Southwest Petroleum University; Oil & Gas Fire Protection Key Laboratory of Sichuan Province; Gas Reservoir Geol & Exploita); Wang, Lingyuan (Southwest Petroleum University); Chen, C. (TU Delft Safety and Security Science; Southwest Petroleum University); Deng, Hongbo (Southwest Petroleum University); Mi, Hongfu (Chongqing University of Science&technology); Tu, Chu (Institute of Computing Technology Chinese Academy of Sciences); Li, Yuanyuan (Southwest Petroleum University)","","2023","Pool fire is a typical example of fire accidents in chemical process industries. Since fire researchers have implemented a variety of measurements to gain insights into pool fire and to prevent fire disasters, there is a need to illustrate how pool fire models influence the risk assessment results. This review intends to consecutively discuss the effect of different physical factors on the burning behavior of pool fire and fire risk assessment. For the most part, this review extracts representative works from abundant pool fire articles in the last years and is subdivided into mass burning rates, entrainment, flame height, pulsation, radiation transfer sections, and risk assessment. On the basis of the latest research, it is indicated that new fire models can provide more accurate and reliable assessment results than previous models. They are not only to reduce the cumbersome work and resources but also to validate computational fluid dynamics (CFD) models that are essential components of performance-based design in fire prevention. Consequently, providing the latest information about how pool fire evolves and how risk assessment is affected, this review paper would be advantageous to fire experts in the future.","Fire risk; Flame height; Mass burning rate; Pool ire; Radiation","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-08-07","","","Safety and Security Science","","",""
"uuid:0343a8a1-822a-4ecc-9387-bb386edabb2d","http://resolver.tudelft.nl/uuid:0343a8a1-822a-4ecc-9387-bb386edabb2d","An Efficient Simulation Approach for Long-term Assessment of CO2 Storage in Complex Geological Formations","Zhang, Z. (TU Delft Numerical Analysis); Wang, Y. (TU Delft Numerical Analysis); Vuik, Cornelis (TU Delft Delft Institute of Applied Mathematics); Hajibeygi, H. (TU Delft Reservoir Engineering)","","2023","We present an efficient compositional framework for simulation of CO2 storage in saline aquifers with complex geological geometries during a lifelong injection and migration process. To improve the computation efficiency, the general framework considers the essential hydrodynamic physics, including hysteresis, dissolution and capillarity, by means of parameterized space. The parameterization method translates physical models into parameterized spaces during an offline stage before simulation starts. Among them, the hysteresis behavior of constitutive relations is captured by the surfaces created from bounding and scanning curves, on which relative permeability and capillarity pressure are determined directly with a pair of saturation and turning point values. The new development also allows for simulation of realistic reservoir models with complex geological features. The numerical framework is validated by comparing simulation results obtained from the Cartesian-box and the converted corner-point grids of the same geometry, and it is applied to a field-scale reservoir eventually. For the benchmark problem, the CO2 is injected into a layered formation. Key processes such as accumulation of CO2 under capillarity barriers, gas breakthrough and dissolution, are well captured and agree with the results reported in literature. The roles of various physical effects and their interactions in CO2 trapping are investigated in a realistic reservoir model using the corner-point grid. It is found that dissolution of CO2 in brine occurs when CO2 and brine are in contact. The effect of residual saturation and hysteresis behavior can be captured by the proposed scanning curve surface in a robust way. The existence of capillarity causes less sharp CO2-brine interfaces by enhancing the imbibition of the brine behind the CO2 plume, which also increases the residual trapping. Moreover, the time-dependent characteristics of the trapping amount reveals the different time scales on which various trapping mechanisms (dissolution and residual) operate and the interplay. The novelty of the development is that essential physics for CO2 trapping are considered by the means of parameterized space. As it is implemented on corner-point grid geometries, it casts a promising approach to predict the migration of CO2 plume, and to assess the amount of CO2 trapped by different trapping mechanisms in realistic field-scale reservoirs.","","en","conference paper","Society of Petroleum Engineers","","","","","","","","","","Numerical Analysis","","",""
"uuid:358ecbae-1949-4a73-b6a3-870d8573eac0","http://resolver.tudelft.nl/uuid:358ecbae-1949-4a73-b6a3-870d8573eac0","Prediction of estimated time of arrival for multi-airport systems via “Bubble” mechanism","Wang, Lechen (The Chinese University of Hong Kong, Shenzhen); Mao, Jianfeng (The Chinese University of Hong Kong, Shenzhen); Li, L. (TU Delft Air Transport & Operations; City University of Hong Kong); Li, Xuechun (The Chinese University of Hong Kong, Shenzhen); Tu, Yilei (The Chinese University of Hong Kong, Shenzhen)","","2023","Predicting Estimated Time of Arrival (ETA) for a Multi-Airport System (MAS) is much more challenging than for a single airport system because of complex air route structure, dense air traffic volume and vagaries of traffic conditions in an MAS. In this work, we propose a novel “Bubble” mechanism to accurately predict medium-term ETA for a Multi-Airport System (MAS), in which the prediction of travel time of an origin–destination (OD) pair is decomposed into two stages, termed as out-MAS and in-MAS stages. For the out-MAS stage, Auto-Regressive Integrated Moving Average (ARIMA) is used to predict the travel time of a flight to reach the MAS boundary. For the in-MAS stage, we construct new spatio-temporal features based on clustering analysis of trajectory patterns facilitated by a novel data-driven hybrid polar sampling method. A sequence-to-sequence prediction model, Multi-variate Stacked Fully connected Bidirectional Long–Short Term Memory, is further developed to achieve multi-step-ahead predictions of in-MAS travel time for each trajectory pattern using the spatio-temporal features as input. Finally, the medium-term ETA prediction for an MAS is achieved by integrating the out-MAS and in-MAS prediction with the help of trajectory pattern prediction via random forest. A case study of predicting medium-term ETA for a typical MAS in China, Guangdong–Hong Kong–Macao Greater Bay Area, is conducted to demonstrate the usage and promising performance of the proposed method in comparison to several commonly used end-to-end learning methods.","Flight estimated time of arrival; Medium-term prediction; Multi-airport systems; Sequence-to-sequence model; Spatio-temporal features; Trajectory pattern clustering","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-04","","","Air Transport & Operations","","",""
"uuid:aa1468f5-123d-4599-a7f0-f251cac158d3","http://resolver.tudelft.nl/uuid:aa1468f5-123d-4599-a7f0-f251cac158d3","Identification and degradation of structural extracellular polymeric substances in waste activated sludge via a polygalacturonate-degrading consortium","Hu, Zhi Yi (Fuzhou University); Lin, Yi Peng (Fuzhou University); Wang, Qing Ting (Fuzhou University); Zhang, Yi Xin (Fuzhou University); Tang, Jie (Fuzhou University); Wang, Shuai (Fuzhou University); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology); Zeng, Raymond Jianxiong (Fuzhou University); Zhang, Fang (Fuzhou University)","","2023","By maintaining the cell integrity of waste activated sludge (WAS), structural extracellular polymeric substances (St-EPS) resist WAS anaerobic fermentation. This study investigates the occurrence of polygalacturonate in WAS St-EPS by combining chemical and metagenomic analyses that identify ∼22% of the bacteria, including Ferruginibacter and Zoogloea, that are associated with polygalacturonate production using the key enzyme EC 5.1.3.6. A highly active polygalacturonate-degrading consortium (GDC) was enriched and the potential of this GDC for degrading St-EPS and promoting methane production from WAS was investigated. The percentage of St-EPS degradation increased from 47.6% to 85.2% after inoculation with the GDC. Methane production was also increased by up to 2.3 times over a control group, with WAS destruction increasing from 11.5% to 28.4%. Zeta potential and rheological behavior confirmed the positive effect which GDC has on WAS fermentation. The major genus in the GDC was identified as Clostridium (17.1%). Extracellular pectate lyases (EC 4.2.2.2 and 4.2.2.9), excluding polygalacturonase (EC 3.2.1.15), were observed in the metagenome of the GDC and most likely play a core role in St-EPS hydrolysis. Dosing with GDC provides a good biological method for St-EPS degradation and thereby enhances the conversion of WAS to methane.","Anaerobic digestion; Clostridium; Pectate lyases; Polygalacturonate-degrading consortium; Structural extracellular polymeric substances; Waste activated sludge","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-01","","","BT/Environmental Biotechnology","","",""
"uuid:20839c6d-6b1e-48dd-9fed-ba7d31c90fbd","http://resolver.tudelft.nl/uuid:20839c6d-6b1e-48dd-9fed-ba7d31c90fbd","Research on Recycling of Phosphorus Tailings Powder in Open-Graded Friction Course Asphalt Concrete","Xiao, Yue (Wuhan University of Technology); Ju, Xinjiang (Wuhan University of Technology); Li, Chao (Wuhan University of Technology); Wang, Tianlei (Wuhan University of Technology); Mr. Wu, R.W. (TU Delft Pavement Engineering; Wuhan University of Technology)","","2023","The reuse in high-value materials is one of the important resource utilization approaches of phosphorus tailings. At present, a mature technical system has been formed on the reuse of phosphorus slag in building materials, and silicon fertilizers in the extraction of yellow phosphorus. But there is a lack of research on the high-value reuse of phosphorus tailings. In order to make safe and effective utilization of phosphorus tailing resources, this research concentrated on how to solve easy agglomeration and difficult dispersion of phosphorus tailing micro-powder, when it was recycled in road asphalt. In the experimental procedure, phosphorus tailing micro-powder is treated in two methods. One method is to directly add it with different contents in asphalt to form a mortar. Dynamic shear tests were used to explore the effect of phosphorus tailing micro-powder on the high-temperature rheological properties of asphalt influence mechanism of material service behavior. The other method is to replace the mineral powder in asphalt mixture. The effect of phosphate tailing micro-powder on the water damage resistance in open-graded friction course (OGFC) asphalt mixtures was illustrated, based on the Marshall stability test and the freeze–thaw split test. The research results show that the performance indicators of the modified phosphorus tailing micro-powder meet the requirements for mineral powder in road engineering. Compared with standard OGFC asphalt mixtures, the residual stability of immersion and freeze–thaw splitting strength were improved when replace the mineral powder. The residual stability of immersion increased from 84.70% to 88.31%, and freeze–thaw splitting strength increased from 79.07% to 82.61%. The results indicate that phosphate tailing micro-powder has a certain positive effect on the water damage resistance. These performance improvements can be attributed to the larger specific surface area for phosphate tailing micro-powder than ordinary mineral powder, which can effectively adsorb asphalt and form structural asphalt. The research results are expected to support the large-scale reuse of phosphorus tailing powder in road engineering.","asphalt mixture; high-temperature rheological properties; moisture damage resistance; phosphorus tailings; solid waste recycling","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:0e623f20-7ec1-46bf-866a-f97415d0da93","http://resolver.tudelft.nl/uuid:0e623f20-7ec1-46bf-866a-f97415d0da93","River Flow Induced Nonlinear Modulation of M4 Overtide in Large Estuaries","Guo, Leicheng (Shanghai Estuarine and Coastal Science Research Center); Zhu, Chunyan (Shanghai Estuarine and Coastal Science Research Center); Cai, Huayang (School of Ocean Engineering and Technology; Sun Yat-sen University); Wang, Zhengbing (TU Delft Hydraulic Engineering; TU Delft Coastal Engineering; Deltares); Townend, Ian (University of Southampton); He, Qing (Shanghai Estuarine and Coastal Science Research Center)","","2023","River discharge is known to enhance tidal damping and tidal wave deformation in estuaries. While the damping effect on astronomical tides has been well documented, river impact on tidal wave deformation and associated overtide generation (shallow water harmonics of one or more astronomical constituents, such as M4) remains insufficiently understood. Overtides affect tidal asymmetry, extreme water levels, and subsequent sediment transport and flooding management, thus meriting in-depth examination. Being inspired by unusual overtide changes in the landward and seaward parts of the Changjiang Estuary under low and high river discharges, in this work, we use a schematized tidal estuary model to systematically explore overtide variations under different river discharges. Model results show enhanced overtide generation in the case with river discharge compared with that without river impact. The M4 amplitude decreases in the landward parts of the estuary, but increases in the seaward parts under increasing river discharges. The potential energy of M4 integrated throughout the estuary shows nonlinear variations and reaches a transitional maximum when the river discharge to tidal mean discharge (R2T) ratio at the mouth is close to unity. Similar nonlinear behaviors are observed for compound tides like MS4 when more astronomical constituents are prescribed and triad tidal interactions are enabled. The space-dependent overtide variability is more profound in large estuaries with high river discharges like the Amazon and Changjiang estuaries. It is ascribed to the inherently nonlinear river-tide interactions, specifically the twofold effects of river discharge in enhancing bottom stress, which simultaneously enhances dissipation of astronomical constituents and reinforces the energy transfer to overtides. These findings highlight the profound nonlinear impact of river discharge on overtides, and inform the study of tidal asymmetry and compound flood risk in large estuaries and deltas.","Bottom stress; Estuary; Overtide; River discharge","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-08-21","","Hydraulic Engineering","Coastal Engineering","","",""
"uuid:66e50a81-b4cc-4a11-84d1-a393b1b59831","http://resolver.tudelft.nl/uuid:66e50a81-b4cc-4a11-84d1-a393b1b59831","Chemical fingerprinting of volatile organic compounds from asphalt binder for quantitative detection","Chang, Xiwen (Wuhan University of Technology); Long, Yongshuang (Wuhan University of Technology); Wang, C. (TU Delft Pavement Engineering); Xiao, Yue (Wuhan University of Technology)","","2023","Asphalt material is an irreplaceable material in road construction. However, it releases VOCs (Volatile Organic Compounds), which do cause pollution to the surrounding environment, during its full life cycle, especially in high-temperature paving stage and summer service time. Asphalt VOCs release mechanism and effective emission reduction technologies are therefore urgently needed. The chemical analysis of VOCs from asphalt binder always invariably excludes a vast number of compounds of unknown relevance, making the quantitative analysis lower data accuracy. In order to address this problem, fingerprint database was developed and introduced in this study, with the detected VOCs data from 104 kinds of asphalt binders. The analysis parameters, including fingerprint components and calibration curves were optimized through quantitative study. With the help of a self-developed fingerprint database, the calculation formulas of single VOC and total released VOCs were established for quantitative analysis of VOCs from asphalt binder. In addition, the influencing mechanism of heating temperature and asphalt types on VOCs volatilization characteristic were explored to achieve emission reduction in asphalt industry.","Asphalt VOCs; Fingerprint components; Quantitative analysis; Release characteristic; VOCs dependency","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-08-24","","","Pavement Engineering","","",""
"uuid:75da2cf8-4ce3-47c4-8d55-1fb275aad9d0","http://resolver.tudelft.nl/uuid:75da2cf8-4ce3-47c4-8d55-1fb275aad9d0","Interfacial Designs of MXenes for Mild Aqueous Zinc-Ion Storage","Guo, R. (TU Delft RST/Storage of Electrochemical Energy; Shaanxi Normal University); Chen, C. (TU Delft RST/Storage of Electrochemical Energy); Bannenberg, L.J. (TU Delft RID/TS/Instrumenten groep); Wang, H. (TU Delft RST/Storage of Electrochemical Energy; Donghua University); Liu, Haozhe (Student TU Delft; Shaanxi Normal University); Yu, Minghao (Technische Universität Dresden); Sofer, Zdenek (University of Chemistry and Technology Prague); Lei, Zhibin (Shaanxi Normal University); Wang, Xuehang (Donghua University)","","2023","Limited Li resources, high cost, and safety risks of using organic electrolytes have stimulated a strong motivation to develop non-Li aqueous batteries. Aqueous Zn-ion storage (ZIS) devices offer low-cost and high-safety solutions. However, their practical applications are at the moment restricted by their short cycle life arising mainly from irreversible electrochemical side reactions and processes at the interfaces. This review sums up the capability of using 2D MXenes to increase the reversibility at the interface, assist the charge transfer process, and thereby improve the performance of ZIS. First, they discuss the ZIS mechanism and irreversibility of typical electrode materials in mild aqueous electrolytes. Then, applications of MXenes in different ZIS components are highlighted, including as electrodes for Zn2+ intercalation, protective layers of Zn anode, hosts for Zn deposition, substrates, and separators. Finally, perspectives are put forward on further optimizing MXenes to improve the ZIS performance.","2D MXenes; interfacial design; mild aqueous electrolyte; Zn-ion batteries; Zn-ion capacitors","en","review","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:ab2f4a11-1a9a-46cd-ba6b-30b297df61d5","http://resolver.tudelft.nl/uuid:ab2f4a11-1a9a-46cd-ba6b-30b297df61d5","Combined Chemoradionuclide Therapy Using Poly(ε-caprolactone-b-ethylene oxide) Micelles as the Delivery Vehicle","Liu, H. (TU Delft RST/Applied Radiation & Isotopes); Nadar, R.A. (TU Delft RST/Applied Radiation & Isotopes; Erasmus MC); Fauzia, R.P. (TU Delft BT/Biocatalysis); Laan, A.C. (TU Delft RST/Technici Pool); Wang, R. (TU Delft RST/Applied Radiation & Isotopes); van Cooten, Quenteijn (Student TU Delft); Carroll, E.C.M. (TU Delft ImPhys/Carroll group); Eelkema, R. (TU Delft ChemE/Advanced Soft Matter); Denkova, A.G. (TU Delft RST/Applied Radiation & Isotopes)","","2023","Combination of therapies is a common strategy in cancer treatment. Such combined therapies only have merit provided that there is superior therapeutic outcome with fewer side effects, compared to single therapies. Here, this work explores the possibility to combine chemotherapy with radionuclide therapy using polymeric micelles as a delivery vehicle. For this purpose, this work prepares poly(ε-caprolactone-b-ethylene oxide) (PCL-PEO) micelles and load them simultaneously with paclitaxel (PTX) and 177Lu(III). This work chooses a 3D tumor spheroid composed of glioblastoma cells (U87) to evaluate the combined treatment. The diffusion of the micelles in the spheroid is investigated by confocal laser scanning microscopy (CLSM) and light-sheet fluorescence microscopy (LSFM). The results show that the micelles are able to penetrate deep into the spheroid within 24 h of incubation and mainly accumulated around or in the lysosomes once in the cell. Subsequently, this work evaluates the cell killing efficiency of the single treatments (PTX or 177Lu(III)) versus combined treatment (PTX + 177Lu(III)) by measuring the growth of the spheroids as well as by performing a cell-viability assay. The results indicate that the combined therapy achieves a superior therapeutic outcome with better cell growth inhibition and cell killing efficiency compared to the single treatments.","biodistribution; cell viability; chemoradionuclide therapy; polymeric micelles; tumor spheroid","en","journal article","","","","","","","","","","","RST/Applied Radiation & Isotopes","","",""
"uuid:b117e566-b049-4766-92f9-309970f6bd7d","http://resolver.tudelft.nl/uuid:b117e566-b049-4766-92f9-309970f6bd7d","Integrating the flow regime and water quality effects into a niche-based metacommunity dynamics model for river ecosystems","Wang, Yibo (Wuhan University); Liu, Pan (Wuhan University); Solomatine, D.P. (TU Delft Water Resources; IHE Delft Institute for Water Education); Li, Liping (Changjiang Water Resources Commission); Wu, Chen (Wuhan University); Han, Dongyang (Wuhan University); Zhang, Xiaojing (Wuhan University); Yang, Zhikai (Wuhan University); Yang, Sheng (China Energy Science and Technology Research Institute Co.,Ltd)","","2023","Aquatic community dynamics are closely dominated by flow regime and water quality conditions, which are increasingly threatened by dam regulation, water diversion, and nutrition pollution. However, further understanding of the ecological impacts of flow regime and water quality conditions on aquatic multi-population dynamics has rarely been integrated into existing ecological models. To address this issue, a new niche-based metacommunity dynamics model (MDM) is proposed. The MDM aims to simulate the coevolution processes of multiple populations under changing abiotic environments, pioneeringly applied to the mid-lower Han River, China. The quantile regression method was used for the first time to derive ecological niches and competition coefficients of the MDM, which are demonstrated to be reasonable by comparing them with the empirical evidence. Simulation results show that the Nash efficiency coefficients for fish, zooplankton, zoobenthos, and macrophytes are more than 0.64, while the Pearson correlation coefficients for them are no less than 0.71. Overall, the MDM performs effectively in simulating metacommunity dynamics. For all river stations, the average contributions of biological interaction, flow regime effects, and water quality effects to multi-population dynamics are 64%, 21%, and 15%, respectively, suggesting that the population dynamics are dominated by biological interaction. For upstream stations, the fish population is 8%–22% more responsive to flow regime alteration than other populations, while other populations are 9%–26% more responsive to changes in water quality conditions than fish. For downstream stations, flow regime effects on each population account for less than 1% due to more stable hydrological conditions. The innovative contribution of this study lies in proposing a multi-population model to quantify the effects of flow regime and water quality on aquatic community dynamics by incorporating multiple indicators of water quantity, water quality, and biomass. This work has potential for the ecological restoration of rivers at the ecosystem level. This study also highlights the importance of considering threshold and tipping point issues when analyzing the “water quantity-water quality-aquatic ecology” nexus in future works.","Ecological niche; Flow regime; Metacommunity dynamics; Quantile regression; River ecosystem; Water quality","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-11","","","Water Resources","","",""
"uuid:75a194fe-1a00-4558-9c6f-492093373318","http://resolver.tudelft.nl/uuid:75a194fe-1a00-4558-9c6f-492093373318","Entropy-Driven Liquid Electrolytes for Lithium Batteries","Wang, Q. (TU Delft RST/Storage of Electrochemical Energy); Zhao, C. (TU Delft RST/Storage of Electrochemical Energy); Yao, Zhenpeng (Shanghai Jiao Tong University); Wang, Jianlin (Chinese Academy of Sciences); Wu, Fangting (Tsinghua University); Kumar, Sai Govind Hari (University of Toronto); Ganapathy, S. (TU Delft RID/TS/Instrumenten groep); Eustace, S.J. (TU Delft BT/Biocatalysis); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2023","Developing liquid electrolytes with higher kinetics and enhanced interphase stability is one of the key challenges for lithium batteries. However, the poor solubility of lithium salts in solvents sets constraints that compromises the electrolyte properties. Here, it is shown that introducing multiple salts to form a high-entropy solution, alters the solvation structure, which can be used to raise the solubility of specific salts and stabilize electrode–electrolyte interphases. The prepared high-entropy electrolytes significantly enhance the cycling and rate performance of lithium batteries. For lithium-metal anodes the reversibility exceeds 99%, which extends the cycle life of batteries even under aggressive cycling conditions. For commercial batteries, combining a graphite anode with a LiNi0.8Co0.1Mn0.1O2 cathode, more than 1000 charge–discharge cycles are achieved while maintaining a capacity retention of more than 90%. These performance improvements with respect to regular electrolytes are rationalized by the unique features of the solvation structure in high-entropy electrolytes. The weaker solvation interaction induced by the higher disorder results in improved lithium-ion kinetics, and the altered solvation composition leads to stabilized interphases. Finally, the high-entropy, induced by the presence of multiple salts, enables a decrease in melting temperature of the electrolytes and thus enables lower battery operation temperatures without changing the solvents.","entropy-driven electrolytes; high-entropy electrolytes; lithium batteries; temperature-dependent electrolytes; weak solvation structures","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:c2210e62-90e3-4879-a1cc-7cf509199dad","http://resolver.tudelft.nl/uuid:c2210e62-90e3-4879-a1cc-7cf509199dad","A novel supply chain network evolving model under random and targeted disruptions","Wang, Jiepeng (Beihang University; Beijing Key Laboratory of Emergency Support Simulation Technologies for City Operations); Zhou, Hong (Beihang University; Beijing Key Laboratory of Emergency Support Simulation Technologies for City Operations); Sun, Xinlei (Nanjing University of Aeronautics and Astronautics); Yuan, Y. (TU Delft Transport and Planning)","","2023","Due to the fact that there is a lack of comprehensive understanding of how the dynamic nature of supply chain networks (SCNs) interrelates with network structures, particularly network topologies under disruptions. This research employs a novel evolving model of a supply chain network (SCNE model) by modifying the Barabási and Albert (BA) model to capture the phenomenon of regional economy and the factor of firms’ attractiveness, considering the degree, the locality preference, and the heterogeneity of SCN members simultaneously. We then analyze the SCNE model via the mean-field theory and conduct simulation study to identify the scale-free characteristic of the proposed supply chain network model. Additionally, we leverage node and edge removal to emulate random and targeted disruptions. We measure and compare the robustness of four network models, i.e., the SCNE model, the Erdos and Rényi (ER) model, the BA model, and the Watts and Strogatz (WS) model using two essential metrics, i.e., the size of the largest connected component and the network efficiency. We find that the robustness of the SCNE model is better than the BA model and the WS model on the whole in the presence of disruptions. Also, from the node level, the SCNE model maintains resilience, behaving similarly to the ER model against random disruptions while it shows vulnerability under targeted disruptions, responding in line with the BA model and the WS model. From the edge level, the network efficiency of the SCNE model changes slowly, and the topological structure of the SCNE model slightly changes initially but decreases rapidly at some value, as well as the BA model, the WS model, and the ER model. Based on the results, we summarize key points of the implications for research and practice in supply chain management.","Complex network; Robustness; Simulation; Supply chain disruptions; Supply chain management","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-27","","","Transport and Planning","","",""
"uuid:7e89aebf-5db7-4400-93b7-8c7da1a575eb","http://resolver.tudelft.nl/uuid:7e89aebf-5db7-4400-93b7-8c7da1a575eb","The quest for a better solvent for the direct hydration of cyclohexene: From molecular screening to process design","Wang, Xiaoda (Fuzhou University); Zhao, Yuqing (Fuzhou University); Han, Lumin (Fuzhou University); Li, Ling (Fuzhou University); Kiss, A.A. (TU Delft ChemE/Product and Process Engineering)","","2023","Cylcohexanol is an essential bulk chemical that can be produced via cyclohexene hydration, a liquid-liquid two-phase reaction that is limited by the low reaction rate and the equilibrium conversion. Adding an appropriate solvent is the most promising method to break through these limitations. However, in previous works the solvent was almost blindly selected without a global consideration. In this work, a rational multiscale method is proposed for the effective selection of an economical and sustainable solvent for the direct hydration of cyclohexene. At the molecular scale, liquid-liquid phase equilibrium was estimated using group contribution methods to rapidly screen the potential solvent candidates from a range of organics, based on the partition coefficient. At the reactor scale, the candidates were experimentally investigated to pick out the solvents that could significantly improve the conversion, without introducing side reactions or deactivating the catalyst. At the process scale, the total annual cost (TAC), CO2 emission, and other metrics were calculated to evaluate the eco-efficiency of all solvents. Using this multi-scale method, acetophenone was selected as an eco-efficient solvent from over 100 organics, resulting in the reduction of TAC by 8 % and CO2 emission by 17 % in the production process. Using acetophenone also led to the increase of cyclohexanol yield from 12.3 % to 27.6 % without the occurrence of side reactions and catalyst deactivation.","Cyclohexene; Hydration; Multi-scale; Process analysis; Solvent selection","en","journal article","","","","","","","","","","","ChemE/Product and Process Engineering","","",""
"uuid:9cea195a-959e-494a-8737-7eea5ac2a5d5","http://resolver.tudelft.nl/uuid:9cea195a-959e-494a-8737-7eea5ac2a5d5","Perspectives on Compound Flooding in Chinese Estuary Regions","Xu, H. (TU Delft Hydraulic Structures and Flood Risk; East China Normal University); Ragno, E. (TU Delft Hydraulic Structures and Flood Risk); Tan, Jinkai (Sun Yat-sen University); Antonini, A. (TU Delft Coastal Engineering); Bricker, J.D. (TU Delft Hydraulic Structures and Flood Risk; University of Michigan); Jonkman, Sebastiaan N. (TU Delft Hydraulic Structures and Flood Risk); Liu, Qing (East China Normal University); Wang, Jun (East China Normal University)","","2023","Extreme surges and rainfall represent major driving factors for compound flooding in estuary regions along the Chinese coast. The combined effect of extreme surges and rainfall (that is, compound floods) might lead to greater impacts than if the drivers occurred in isolation. Hence, understanding the frequency and severity of compound flooding is important for improving flood hazard assessment and compound flood resilience in coastal cities. In this study, we examined the dependence between extreme surges and corresponding rainfall events in 26 catchments along the Chinese coastline during typhoon and non-typhoon seasons using copula functions, to identify where the two drivers more often occur together and the implication for flood management in these locations. We found that the interaction between flood drivers is statistically significant in 10 catchments located around Hainan Island (south) and Shanghai, where surge peaks occur mainly during the typhoon season and around the Bohai Sea (north), where surge peaks occur mainly during the non-typhoon season. We further applied the copula-based framework to model the dependence between surge peaks and associated rainfall and estimate their joint and conditional probability in two specific locations—Hainan Island and the Bohai Sea, where the correlation between flood drivers is statistically significant. We observed that in Hainan Island where most of the surge peaks occur during the typhoon season, extreme rainfall events during the typhoon season are generally more intense compared to annual maxima rainfall. In contrast, around the Bohai Sea where surge peaks occur mainly outside the typhoon season, rainfall is less intense than annual maxima rainfall. These results show that the interaction between extreme surges and rainfall can provide valuable insight when designing coastal and urban infrastructure, especially in highly populated urban areas prone to both coastal and pluvial flooding, such as many Chinese coastal cities.","China; Coastal catchments; Compound flooding; Copula function; Extreme surge; Optimal threshold","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:d1f9bdaa-c33a-419c-833b-26659a40968b","http://resolver.tudelft.nl/uuid:d1f9bdaa-c33a-419c-833b-26659a40968b","Structure-Based Redesign of a Methanol Oxidase into an “Aryl Alcohol Oxidase” for Enzymatic Synthesis of Aromatic Flavor Compounds","Wu, Bin (South China University of Technology); Wang, S. (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Ma, Yunjian (South China University of Technology); Yuan, Shuguang (Chinese Academy of Sciences); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Yonghua (South China University of Technology)","","2023","Alcohol oxidases (AOxs) catalyze the aerobic oxidation of alcohols to the corresponding carbonyl products (aldehydes or ketones), producing only H2O2 as the byproduct. The majority of known AOxs, however, have a strong preference for small, primary alcohols, limiting their broad applicability, e.g., in the food industry. To broaden the product scope of AOxs, we performed structure-guided enzyme engineering of a methanol oxidase from Phanerochaete chrysosporium (PcAOx). The substrate preference was extended from methanol to a broad range of benzylic alcohols by modifying the substrate binding pocket. A mutant (PcAOx-EFMH) with four substitutions exhibited improved catalytic activity toward benzyl alcohols with increased conversion and kcat toward the benzyl alcohol from 11.3 to 88.9% and from 0.5 to 2.6 s-1, respectively. The molecular basis for the change of substrate selectivity was analyzed by molecular simulation.","alcohol oxidase; flavor compounds; molecular modification; substrate selectivity","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-11","","","BT/Biocatalysis","","",""
"uuid:45d7ce22-97ed-4c26-b3f6-a1b2dd0cdb7d","http://resolver.tudelft.nl/uuid:45d7ce22-97ed-4c26-b3f6-a1b2dd0cdb7d","Ultimate soil resistance of the laterally loaded pile in uniform sand","Wang, H. (TU Delft Geo-engineering; Norwegian Geotechnical Institute); Wang, L. Z. (Zhejiang University); Askarinejad, A. (TU Delft Geo-engineering); Hong, Y. (Zhejiang University); He, B. (PowerChina Huadong Engineering Corporation Limited)","","2023","Piles have been widely used as foundations to resist lateral loads. For the design of a laterally loaded pile, one of the most important inputs is the ultimate soil resistance (pult = KultDσv′,whereKult is the ultimate lateral soil resistance coefficient, D is the pile diameter, and σv′ is the vertical effective stress). However, great discrepancy can be found in the existing design equations for piles in sand. To provide new insights and clarify the discrepancy in previous studies, in this study, a series of numerical simulations were performed on piles of different configurations using the finite element model validated by centrifuge pile tests. The computed results suggest that Kult is a function of depth ratios z/D and z/L for the flexible and rigid piles, respectively (where z is the absolute depth and L is the embedded pile length), and all existing design equations failed to reproduce the magnitude and distribution of Kult . Additionally, the Kult of horizontally translated fixed-head rigid piles exhibits the same pattern as that of free-head flexible piles, suggesting that the difference between free-head flexible piles and rigid piles is caused by the change of failure modes.","finite element modelling; hypoplastic soil model; laterally loaded pile; sand; ultimate soil resistance","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public","","2023-09-15","","","Geo-engineering","","",""
"uuid:f52a6d49-e458-47c6-b1d0-13001deb07f7","http://resolver.tudelft.nl/uuid:f52a6d49-e458-47c6-b1d0-13001deb07f7","Electrical Control of Uniformity in Quantum Dot Devices","Meyer, M. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Déprez, C.C. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); van Abswoude, Timo R. (Kavli institute of nanoscience Delft; Student TU Delft); Meijer, Ilja N. (Kavli institute of nanoscience Delft; Student TU Delft); Liu, Dingshan (Kavli institute of nanoscience Delft; Student TU Delft); Wang, C.A. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Karwal, S. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre); Oosterhout, S.D. (TU Delft BUS/TNO STAFF); Borsoi, F. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Sammak, A. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre); Hendrickx, N.W. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Scappucci, G. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Veldhorst, M. (TU Delft QN/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)","","2023","Highly uniform quantum systems are essential for the practical implementation of scalable quantum processors. While quantum dot spin qubits based on semiconductor technology are a promising platform for large-scale quantum computing, their small size makes them particularly sensitive to their local environment. Here, we present a method to electrically obtain a high degree of uniformity in the intrinsic potential landscape using hysteretic shifts of the gate voltage characteristics. We demonstrate the tuning of pinch-off voltages in quantum dot devices over hundreds of millivolts that then remain stable at least for hours. Applying our method, we homogenize the pinch-off voltages of the plunger gates in a linear array for four quantum dots, reducing the spread in pinch-off voltages by one order of magnitude. This work provides a new tool for the tuning of quantum dot devices and offers new perspectives for the implementation of scalable spin qubit arrays.","hysteresis; quantum dot; spin qubit; uniformity","en","journal article","","","","","","","","","","","QCD/Veldhorst Lab","","",""
"uuid:d9911bd6-3296-4766-9e39-c342188fd4b0","http://resolver.tudelft.nl/uuid:d9911bd6-3296-4766-9e39-c342188fd4b0","Incorporating indirect costs into energy system optimization models: Application to the Dutch national program Regional Energy Strategies","Wang, N. (TU Delft Energie and Industrie; TNO); Verzijlbergh, R.A. (TU Delft Energie and Industrie); Heijnen, P.W. (TU Delft Energie and Industrie); Herder, P.M. (TU Delft ChemE/Chemical Engineering)","","2023","Energy system optimization models are widely used to aid long-term investment decision-making for energy systems. From a socio-technical system viewpoint, existing models focus on the cost modeling of the technical subsystem, while the indirect costs of the social subsystem are not often modeled. This paper incorporates indirect costs into such a model, including those associated with generation capacity, energy production, and bilateral trades, respectively. As a proof-of-concept, the model has been applied to a case study for the Dutch power system, reflecting the Dutch national program Regional Energy Strategies, where regions collectively plan wind and solar energy capacities. We conclude that incorporating indirect costs significantly changed the optimal investment capacities and the associated costs for the regions compared to benchmark results from the conventional models. Furthermore, in this case study, a potential free-rider problem with regard to the national climate target occurs. Our model is used as a negotiation simulator to inform the regions about the hypothetical free-riding behaviors and thus helps to achieve a socially acceptable investment plan. The proposed energy system optimization model with indirect costs goes beyond the prevalent cost-minimization paradigm, and can be used to study transaction costs, trading barriers, and willingness to pay.","Energy markets; Energy system optimization model; Energy system planning; Indirect costs; Transaction costs; Willingness to pay","en","journal article","","","","","","","","","","ChemE/Chemical Engineering","Energie and Industrie","","",""
"uuid:5b9a2c92-6e2f-4da6-9a7f-a598ef190c6a","http://resolver.tudelft.nl/uuid:5b9a2c92-6e2f-4da6-9a7f-a598ef190c6a","Modeling the impact of lane-changing's anticipation on car-following behavior","Chen, Kequan (Southeast University); Knoop, V.L. (TU Delft Transport and Planning); Liu, Pan (Southeast University); Li, Zhibin (Southeast University); Wang, Yuxuan (Southeast University)","","2023","Lane-changing (LC) in congested traffic has been identified as a trigger for the sudden deceleration behavior of the new follower in the target lane, leading to severe traffic disturbances. Thus, investigating the response of the new follower to an LC maneuver is an important research topic in the literature. To date, numerous efforts have been devoted to understanding the impact of the lane changer on the new follower after the insertion, while less attention has been given to this influence during the pre-insertion stage (anticipation). Therefore, this paper aims to establish a new car-following (CF) model to capture the new follower's driving behavior during anticipation. Specifically, we introduce an attention mechanism deviating from Newell's CF rules to quantify the impact of anticipation. Then, we apply a neural network with an attention layer to estimate the attention mechanism and incorporate it into the Newell CF model, which yields a new CF model, denoted as CF_Attention. Using real-world trajectory data, we design three experiments and select three representative CF models to validate the CF_Attention. The results indicate that the CF_Attention outperforms the other models in predicting the new follower's trajectory, which is not affected by the heterogeneous behavior of the new follower and the anticipation duration. Additionally, the CF_Attention is proven effective in capturing the speed-space relationship and the formation of oscillation. Finally, our transferability test suggests that the CF_Attention is promising for different locations and times without requiring retraining. The results of this study could advance the integration of the LC impact and CF behavior, and could be implemented into commercial traffic simulation programs to describe vehicle movements in traffic flow more accurately.","Anticipation; Car-following model; Lane-changing impact; Trajectory data","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-30","","","Transport and Planning","","",""
"uuid:8f16d09c-6485-4564-ae54-87d94f737042","http://resolver.tudelft.nl/uuid:8f16d09c-6485-4564-ae54-87d94f737042","Lateral behavior of monopiles in sand under monotonic loading: Insights and a new simple design model","Wang, H. (TU Delft Geo-engineering); Lehane, B. M. (University of Western Australia); Bransby, M. F. (University of Western Australia); Wang, L. Z. (Zhejiang University); Hong, Y. (Zhejiang University); Askarinejad, A. (TU Delft Geo-engineering)","","2023","This paper presents a synthesis of recent and new research conducted by the authors on laterally loaded monopiles in drained sand. The research involved reduced-scale field tests, centrifuge model tests, finite element (FE) simulations and comparisons of design approaches with published experimental data. The influence of the monopile base on lateral response is first discussed by drawing on field tests and numerical simulations and it is shown that the base generally provides a negligible contribution. The applicability of the API p-y formulation is then investigated through systematic FE analyses. The results show that this formulation leads to inaccurate predictions largely due to the assumption of a high initial stiffness varying linearly with depth and an unrealistic hyperbolic tangent back-bone function. Based on new insights into pile-soil interaction together with elastic simulations of laterally loaded rigid piles and new observations based on 26 pile tests, a simple rotational spring model is proposed to allow rapid quantification of the non-linear response of rigid monopiles in uniform sand. The effect of monopile flexibility is then added through a new straightforward correction factor based on 80 extra FE simulations. Finally, an example application of the proposed approach for a typical monopile design is presented.","Lateral load; Monopiles; Offshore wind turbines; Pile-soil interaction; Sands; Stiffness","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:9152b02a-61cc-4edc-a4c6-e483a82cbcec","http://resolver.tudelft.nl/uuid:9152b02a-61cc-4edc-a4c6-e483a82cbcec","In situ monitoring redox processes in energy storage using UV–Vis spectroscopy","Zhang, Danzhen (Drexel University); Wang, Ruocun (John) (Drexel University); Wang, Xuehang (TU Delft RST/Storage of Electrochemical Energy; Drexel University); Gogotsi, Yury (Drexel University)","","2023","Understanding energy storage mechanisms in electrochemical energy storage devices lays the foundations for improving their energy and power density. Here we introduce in situ ultraviolet–visible (UV–Vis) spectroscopy method to distinguish battery-type, pseudocapacitive and electrical double-layer charge storage processes. On the basis of Ti3C2Tx MXene in aqueous acidic and neutral electrolytes, and lithium titanium oxide in an organic electrolyte, we found a correlation between the evolution of UV–Vis spectra and the charge storage mechanism. The electron transfer number for Ti3C2Tx in an acidic electrolyte was calculated using quantitative analysis, which was close to previous measurements using X-ray absorption spectroscopy. Further, we tested the methodology to distinguish the non-Faradaic process in Ti3C2Tx MXene in a water-in-salt electrolyte, despite well-defined peaks in cyclic voltammograms. In situ UV–Vis spectroscopy is a fast and cost-effective technique that effectively supplements electrochemical characterization to track changes in oxidation state and materials chemistry and determine the charge storage mechanism.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-06","","","RST/Storage of Electrochemical Energy","","",""
"uuid:138bc2a5-6273-4c1e-b3f4-d326dfc559a3","http://resolver.tudelft.nl/uuid:138bc2a5-6273-4c1e-b3f4-d326dfc559a3","Leaderless Consensus of Heterogeneous Multiple Euler-Lagrange Systems With Unknown Disturbance","Wang, Shimin (Queen’s University); Zhang, Hongwei (Harbin Institute of Technology); Baldi, S. (TU Delft Team Bart De Schutter; Southeast University); Zhong, Renxin (Sun Yat-sen University)","","2023","This article studies the leaderless consensus problem of heterogeneous multiple networked Euler-Lagrange systems subject to persistent disturbances with unknown constant biases, amplitudes, initial phases, and frequencies. The main characteristic of this study is that none of the agents has information of a common reference model or of a common reference trajectory. Therefore, the agents must simultaneously and in a distributed way: achieve consensus to a common reference model (group model); achieve consensus to a common reference trajectory; and reject the unknown disturbances. We show that this is possible via a suitable combination of techniques of distributed 'observers,' internal model principle and adaptive regulation. The proposed design generalizes recent results on group model learning, which have been studied for linear agents over undirected networks. In this article, group model learning is achieved for Euler-Lagrange dynamics over directed networks in the presence of persistent unknown disturbances.","Cooperative control; Euler-Lagrange system; leaderless consensus; multiagent system; output regulation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-05","","","Team Bart De Schutter","","",""
"uuid:2ee3d4f7-931e-4740-955f-03ce9efe02f0","http://resolver.tudelft.nl/uuid:2ee3d4f7-931e-4740-955f-03ce9efe02f0","Large-Area and Visible-Light-Driven Heterojunctions of In2O3/Graphene Built for ppb-Level Formaldehyde Detection at Room Temperature","Guo, Lanpeng (South China Normal University); Liang, Hongping (South China Normal University); Hu, Huiyun (South China Normal University); Shi, Shenbin (South China Normal University); Wang, Chenxu (South China Normal University); Li, Hao (South China Normal University); Lee, Yi Kuen (The Hong Kong University of Science and Technology); French, P.J. (TU Delft Bio-Electronics); Wang, Yao (South China Normal University)","","2023","Achieving convenient and accurate detection of indoor ppb-level formaldehyde is an urgent requirement to ensure a healthy working and living environment for people. Herein, ultrasmall In2O3 nanorods and supramolecularly functionalized reduced graphene oxide are selected as hybrid components of visible-light-driven (VLD) heterojunctions to fabricate ppb-level formaldehyde (HCHO) gas sensors (named InAG sensors). Under 405 nm visible light illumination, the sensor exhibits an outstanding response toward ppb-level HCHO at room temperature, including the ultralow practical limit of detection (pLOD) of 5 ppb, high response (Ra/Rg = 2.4, 500 ppb), relatively short response/recovery time (119 s/179 s, 500 ppb), high selectivity, and long-term stability. The ultrasensitive room temperature HCHO-sensing property is derived from visible-light-driven and large-area heterojunctions between ultrasmall In2O3 nanorods and supramolecularly functionalized graphene nanosheets. The performance of the actual detection toward HCHO is evaluated in a 3 m3 test chamber, confirming the practicability and reliability of the InAG sensor. This work provides an effective strategy for the development of low-power-consumption ppb-level gas sensors.","formaldehyde sensing; InO nanorods; room temperature; supramolecularly functionalized graphene; visible-light-driven heterojunctions","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-01","","","Bio-Electronics","","",""
"uuid:5828ef1f-d61e-4c57-9536-5532664a7106","http://resolver.tudelft.nl/uuid:5828ef1f-d61e-4c57-9536-5532664a7106","Hard superconducting gap in germanium","Tosato, A. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Levajac, V. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, J. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Boor, Casper J. (Student TU Delft; Kavli institute of nanoscience Delft); Borsoi, F. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Botifoll, Marc (Catalan Institute of Nanoscience and Nanotechnology, Barcelona); Sammak, A. (TU Delft BUS/TNO STAFF); Veldhorst, M. (TU Delft QN/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Scappucci, G. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)","","2023","The co-integration of spin, superconducting, and topological systems is emerging as an exciting pathway for scalable and high-fidelity quantum information technology. High-mobility planar germanium is a front-runner semiconductor for building quantum processors with spin-qubits, but progress with hybrid superconductor-semiconductor devices is hindered by the difficulty in obtaining a superconducting hard gap, that is, a gap free of subgap states. Here, we address this challenge by developing a low-disorder, oxide-free interface between high-mobility planar germanium and a germanosilicide parent superconductor. This superconducting contact is formed by the thermally-activated solid phase reaction between a metal, platinum, and the Ge/SiGe semiconductor heterostructure. Electrical characterization reveals near-unity transparency in Josephson junctions and, importantly, a hard induced superconducting gap in quantum point contacts. Furthermore, we demonstrate phase control of a Josephson junction and study transport in a gated two-dimensional superconductor-semiconductor array towards scalable architectures. These results expand the quantum technology toolbox in germanium and provide new avenues for exploring monolithic superconductor-semiconductor quantum circuits towards scalable quantum information processing.","","en","journal article","","","","","","","","","","","QCD/Scappucci Lab","","",""
"uuid:a43169e9-a401-4245-96f2-7de5eeac6ce8","http://resolver.tudelft.nl/uuid:a43169e9-a401-4245-96f2-7de5eeac6ce8","Experimental Simulation of Larger Quantum Circuits with Fewer Superconducting Qubits","Ying, Chong (University of Science and Technology of China); Cheng, Bin (University of Technology Sydney; Southern University of Science and Technology); Zhao, Youwei (University of Science and Technology of China); Huang, He Liang (University of Science and Technology of China; Henan Key Laboratory of Quantum Information and Cryptography, Zhengzhou); Zhang, Y.N. (TU Delft QID/Dobrovitski Group; Southern University of Science and Technology); Gong, Ming (University of Science and Technology of China); Wu, Yulin (University of Science and Technology of China); Wang, S. (University of Science and Technology of China); Liang, Futian (University of Science and Technology of China)","","2023","Although near-term quantum computing devices are still limited by the quantity and quality of qubits in the so-called NISQ era, quantum computational advantage has been experimentally demonstrated. Moreover, hybrid architectures of quantum and classical computing have become the main paradigm for exhibiting NISQ applications, where low-depth quantum circuits are repeatedly applied. In order to further scale up the problem size solvable by the NISQ devices, it is also possible to reduce the number of physical qubits by ""cutting""the quantum circuit into different pieces. In this work, we experimentally demonstrated a circuit-cutting method for simulating quantum circuits involving many logical qubits, using only a few physical superconducting qubits. By exploiting the symmetry of linear-cluster states, we can estimate the effectiveness of circuit-cutting for simulating up to 33-qubit linear-cluster states, using at most 4 physical qubits for each subcircuit. Specifically, for the 12-qubit linear-cluster state, we found that the experimental fidelity bound can reach as much as 0.734, which is about 19% higher than a direct implementation on the same 12-qubit superconducting processor. Our results indicate that circuit-cutting represents a feasible approach of simulating quantum circuits using much fewer qubits, while achieving a much higher circuit fidelity.","","en","journal article","","","","","","","","","","","QID/Dobrovitski Group","","",""
"uuid:6a561279-0f2f-48e0-a1dc-585510fb6d73","http://resolver.tudelft.nl/uuid:6a561279-0f2f-48e0-a1dc-585510fb6d73","Lessons Learned from Designing and Evaluating CLAICA: A Continuously Learning AI Cognitive Assistant","Kernan Freire, S. (TU Delft Internet of Things); Niforatos, E. (TU Delft Internet of Things); Wang, C.W. (TU Delft Human-Centred Artificial Intelligence); Ruiz Arenas, S. (TU Delft Internet of Things; Universidad EAFIT); Foosherian, Mina (University of Bremen); Wellsandt, Stefan (University of Bremen); Bozzon, A. (TU Delft Human-Centred Artificial Intelligence)","","2023","Learning to operate a complex system, such as an agile production line, can be a daunting task. The high variability in products and frequent reconfigurations make it difficult to keep documentation up-to-date and share new knowledge amongst factory workers. We introduce CLAICA, a Continuously Learning AI Cognitive Assistant that supports workers in the aforementioned scenario. CLAICA learns from (experienced) workers, formalizes new knowledge, stores it in a knowledge base, along with contextual information, and shares it when relevant. We conducted a user study with 83 participants who performed eight knowledge exchange tasks with CLAICA, completed a survey, and provided qualitative feedback. Our results provide a deeper understanding of how prior training, context expertise, and interaction modality affect the user experience of cognitive assistants. We draw on our results to elicit design and evaluation guidelines for cognitive assistants that support knowledge exchange in fast-paced and demanding environments, such as an agile production line.","chatbots; cognitive assistant; human-centered AI; industry 5.0; knowledge sharing; knowledge-based AI","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Internet of Things","","",""
"uuid:5683d13d-c469-45e0-a15c-a8b5b7337153","http://resolver.tudelft.nl/uuid:5683d13d-c469-45e0-a15c-a8b5b7337153","Effects of phosphate addition on the removal of disinfection by-product formation potentials by biological activated carbon filtration","Wang, Feifei (Shanghai University); Hua, Yulin (Shanghai University); Pan, Jiazheng (Shanghai University); Zhou, Jie (Shanghai University); Hea, Chiquan (Shanghai University); Hofman, J.A.M.H. (University of Bath); Chu, Wenhai (Tongji University); van der Hoek, J.P. (TU Delft Sanitary Engineering; Waternet)","","2023","In drinking water treatment plants (DWTPs), the widely used biological activated carbon filters (BACFs), as the last barrier before disinfection, can remove dissolved organic matter (DOM) known as precursors of disinfection by-products (DBPs). Whether phosphate addition can improve water purification and DBP control of BACFs is still controversial. This study investigated short-term and long-term effects of phosphate addition on controlling DBP formation potentials (FPs) by BACFs via column and batch experiments. The BAC columns presented good water purification performance: they removed around 50 % DOM, nearly all fulvic acid-likes and humic acid-likes as well as 5 %–70 % chlor(am)innated THM4, HAA9 and HAN4 FPs (except chloraminated THM4 FPs), which was mainly contributed by aerobic bacteria not anoxic bacteria. Phosphate addition within 7–14 days further improved removals of DOM, aromatic organics, fluorescence fractions in DOM as well as HAA9 and HAN4 FPs (especially TCAA FP and TCAN FP) to different extent. However, this improvement did not last longer, and removals of DOM, aromatic organics, two fluorescence fractions (soluble microbial byproduct-likes and humic acid-likes) and DBP FPs decreased despite long-term phosphate addition. Oxic and anoxic batch experiments showed that the positive response of water purification to short-term phosphate addition was also mainly attributed to aerobic bacteria and not to anoxic bacteria. For example, the former decreased DOM and DBP FPs, while the latter increased protein- and tryptophan-like substances as well as chloraminated THM4 FPs. Phosphate addition resulted in EPS increase in anoxic reactors and decrease in oxic reactors. These results indicated that a high dissolved oxygen in BACFs may be helpful for water purification and DBP control. Overall, short-term phosphate addition into phosphorus-limited water is beneficial for BACFs to control DBPs while long-term addition has no effect. Therefore, an intermittent phosphate addition into BACFs is suggested to control DBPs in DWTPs.","Anoxic condition; Chloramination; Chlorination; Disinfection by-products; Oxic condition; Phosphate","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-20","","","Sanitary Engineering","","",""
"uuid:cb21b0be-0063-434f-a6ee-ec5c4d30c8f1","http://resolver.tudelft.nl/uuid:cb21b0be-0063-434f-a6ee-ec5c4d30c8f1","Surrogate modelling of railway pantograph-catenary interaction using deep Long-Short-Term-Memory neural networks","Song, Yang (Southwest Jiaotong University; Norwegian University of Science and Technology (NTNU)); Wang, H. (TU Delft Railway Engineering); Frøseth, Gunnstein (Norwegian University of Science and Technology (NTNU)); Nåvik, Petter (Norwegian University of Science and Technology (NTNU)); Liu, Zhigang (Southwest Jiaotong University); Rønnquist, Anders (Norwegian University of Science and Technology (NTNU))","","2023","The interaction performance of the pantograph-catenary is of great importance as it directly determines the current collection quality and operational safety of trains. The finite element method (FEM) is dominantly used for simulating pantograph-catenary interaction, which is normally computationally heavy. In this work, addressing the tremendous computational cost of FEM models, a surrogate model for fast simulations of pantograph-catenary interaction is proposed using deep learning. A dataset containing 30,000 cases of pantograph-catenary interaction is generated by a validated FEM model. A Long-Short-Term-Memory (LSTM) neural network is proposed to learn the inherent nonlinearity between the input model parameters and the output pantograph-catenary contact force from data. The resulting prediction performance indicates that contact forces predicted by the surrogate model are consistent with those simulated by FEM, while the computational efforts of the surrogate model are negligible compared with FEM. Prediction performances using different network architectures and configurations are compared to determine the optimal setting for a pantograph-catenary system. The LSTM-based surrogate model shows high efficiency for simulating pantograph-catenary interactions and promising practicability in optimising catenary structural parameters for design or upgrade.","Contact force; Deep learning; High-speed railway; LSTM; Pantograph-catenary interaction; Surrogate model","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:dfefe8d9-41fa-4aab-a26a-f89467afedc0","http://resolver.tudelft.nl/uuid:dfefe8d9-41fa-4aab-a26a-f89467afedc0","Floodplain Connecting Channels as Critical Paths for Hydrological Connectivity of Deltaic River Networks","Gao, Weilun (Guangdong University of Technology); Wang, Zhengbing (TU Delft Coastal Engineering; Beijing Normal University); Kleinhans, Maarten G. (Universiteit Utrecht); Miao, Chiyuan (Beijing Normal University); Cui, Baoshan (Beijing Normal University); Shao, Dongdong (Beijing Normal University)","","2023","A river bifurcation is critical for distributing water, sediment and nutrients to the downstream branches of deltaic river networks. However, the downstream branches of a bifurcation can be linked by a connecting channel cutting through deltaic floodplains. The floodplain connecting channel as a downstream control can affect water partitioning at the river bifurcation and hence the hydrological connectivity of the river network. However, its effects are still largely elusive. In this study, we explored how a connecting channel linking downstream branches affects water partitioning at the upstream bifurcation and water distribution along the two branches. The investigation was conducted through idealized numerical simulations using Delft3D, followed by analysis of the cascading effects on the hydrological connectivity of river networks using graph theory. The results show that connecting channels can mitigate asymmetric water partitioning at the upstream bifurcation. However, this happens at the expense of inducing more uneven flow at the downstream outlets. The flow adjustment is due to the altered spatial water surface slope in the two branches associated with the flow exchange from one channel to the other via the connecting channel. Further analysis of hydrological connectivity shows that connecting channels can generally reduce the vulnerability of the channel network to hydrological alterations, especially changing inflow, by enhancing flow exchange between the two branches. Our results suggest that connecting channels are critical paths for hydrological connectivity, which have important implications for the management of deltaic river networks and their floodplains.","connecting channel; deltaic river network; floodplain; hydrological connectivity; river bifurcation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-10","","","Coastal Engineering","","",""
"uuid:3a8bd2eb-4941-432a-83c6-74db810206d2","http://resolver.tudelft.nl/uuid:3a8bd2eb-4941-432a-83c6-74db810206d2","Mechanism of assembly of an elongation-competent SARS-CoV-2 replication transcription complex","Klein, M. (TU Delft BN/Martin Depken Lab; Vrije Universiteit Amsterdam); Bera, Subhas C. (Friedrich-Alexander-Universität Erlangen-Nürnberg); Anderson, Thomas K. (University of Wisconsin-Madison); Wang, Bing (Ohio State University); Papini, Flavia S. (Friedrich-Alexander-Universität Erlangen-Nürnberg); Arnold, Jamie J. (University of North Carolina at Chapel Hill); Cameron, Craig E. (University of North Carolina at Chapel Hill); Depken, S.M. (TU Delft BN/Bionanoscience); Dulin, D. (TU Delft BN/Nynke Dekker Lab; Vrije Universiteit Amsterdam)","","2023","","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-08-10","","BN/Bionanoscience","BN/Martin Depken Lab","","",""
"uuid:c89d09f0-22d8-4120-8e27-5f2524a76eee","http://resolver.tudelft.nl/uuid:c89d09f0-22d8-4120-8e27-5f2524a76eee","Adaptation timescales of estuarine systems to human interventions","van Maren, D.S. (TU Delft Environmental Fluid Mechanics; East China Normal Univeristy; Deltares); Colina Alonso, A. (TU Delft Coastal Engineering; Deltares); Engels, A. (Niedersächsischer Landesbetrieb für Wasserwirtschaft); Vandenbruwaene, W. (Flanders Hydraulics Research); de Vet, P.L.M. (TU Delft Coastal Engineering; Deltares); Vroom, J. (Deltares); Wang, Zhengbing (TU Delft Coastal Engineering)","","2023","Many estuaries and tidal basins are strongly influenced by various human interventions (land reclamations, infrastructure development, channel deepening, dredging and disposal of sediments). Such interventions lead to a range of hydrodynamic and morphological responses (a changing channel depth, tidal amplitude and/or suspended sediment concentration). The response time of a system to interventions is determined by the processes driving this change, the size of the system, and the magnitude of the intervention. A quantitative understanding of the response time to an intervention therefore provides important insight into the processes driving the response. In this paper we develop and apply a methodology to estimate the response timescales of human interventions using available morphological and hydraulic data. Fitting an exponential decay function to data with sufficient temporal resolution yields an adaptation timescale (and equilibrium value) of the tidal range and deposited sediment volumes. The method has been applied in the Dutch Wadden Sea, where two large basins were reclaimed and where long-term and detailed bathymetric maps are available. Exponential fitting the morphological data revealed that closure of a very large part of a tidal basin in the Wadden Sea initially led to internal redistribution and import of coarse and fine sediments, and was followed by a phase of extensive redistribution while only fine-grained sediments are imported. Closure of a smaller part of a smaller basin led to shorter response timescales, and these response timescales are also more sensitive to rising mean sea levels or high waters. The method has also been applied to tidal water level observations in the Scheldt and Ems estuaries. Exponential fits to tidal data reveal that adaptation timescales are shortest at the landward limit of dredging. The adaptation time increases in the landward direction because of retrogressive erosion (Scheldt) or lowering of the hydraulic roughness (Ems). The seaward increase in adaptation time is related to the seaward widening of both systems.","human interventions; morphological adaption; response timescales; estuaries; tidal basins","en","journal article","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:3ee9d601-36ea-4e31-8878-524a58a6b0de","http://resolver.tudelft.nl/uuid:3ee9d601-36ea-4e31-8878-524a58a6b0de","EFE: End-to-end Frame-to-Gaze Estimation","Balim, Haldun (ETH Zürich); Park, Seonwook (Lunit Inc.); Wang, Xi (ETH Zürich); Zhang, X. (TU Delft Pattern Recognition and Bioinformatics); Hilliges, Otmar (ETH Zürich)","O’Conner, Lisa (editor)","2023","Despite the recent development of learning-based gaze estimation methods, most methods require one or more eye or face region crops as inputs and produce a gaze direction vector as output. Cropping results in a higher resolution in the eye regions and having fewer confounding factors (such as clothing and hair) is believed to benefit the final model performance. However, this eye/face patch cropping process is expensive, erroneous, and implementation-specific for different methods. In this paper, we propose a frame-to-gaze network that directly predicts both 3D gaze origin and 3D gaze direction from the raw frame out of the camera without any face or eye cropping. Our method demonstrates that direct gaze regression from the raw downscaled frame, from FHD/HD to VGA/HVGA resolution, is possible despite the challenges of having very few pixels in the eye region. The proposed method achieves comparable results to state-of-the-art methods in Point-of-Gaze (PoG) estimation on three public gaze datasets: GazeCapture, MPIIFaceGaze, and EVE, and generalizes well to extreme camera view changes.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-14","","","Pattern Recognition and Bioinformatics","","",""
"uuid:a1317215-c660-437c-84c0-caa969b4c6f5","http://resolver.tudelft.nl/uuid:a1317215-c660-437c-84c0-caa969b4c6f5","Nanoprobes for PET/MR Imaging","Liu, Huanhuan (Zhengzhou University); Wang, R. (TU Delft RST/Applied Radiation & Isotopes); Gao, Haiyan (Zhengzhou University); Chen, Lijuan (Zhengzhou University); Li, Xiaochen (Zhengzhou University); Yu, Xuan (Zhengzhou University); Wu, Yaping (Zhengzhou University); Bai, Yan (Zhengzhou University); Wei, W. (Zhengzhou University); Wang, Meiyun (Zhengzhou University; Henan University)","","2023","The development of clinical imaging techniques significantly improves diagnostic accuracy and provides guidance for personalized treatment of individuals. However, every single imaging modality has its distinct drawbacks that cannot fully fulfil the diagnosis requirement. Thus, rational combination of different imaging modalities can achieve more comprehensive information of disease and in this way provide better personalized treatment strategy. The hybrid PET/MRI has drawn increasing attention since its first clinical application. Imaging probes play an essential role in achieving qualified figures with accurate information of diseases. The application of nanotechnology promotes the development of versatile molecular probes for PET/MRI technique. Though there is an emerging clinical requirement, only a small number of multimodal PET/MRI probes have been investigated in preclinical research. Thus, this review tries to thoroughly summarize the nano-sized PET/MRI probes on their design, preparation and biological application. By discussing the strength and limitations of these current available PET/MRI multimodal probes, this work aims to figure out the further research direction and promote the possible clinic translation of the novel PET/MRI probes.","dual-modality imaging; MRI; nanoprobes; PET; radiolabeling","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-17","","","RST/Applied Radiation & Isotopes","","",""
"uuid:46ccf67c-1e42-4142-902a-a87d360baf4b","http://resolver.tudelft.nl/uuid:46ccf67c-1e42-4142-902a-a87d360baf4b","Super-Resolution Harmonic Retrieval of Non-Circular Signals","Zhang, Yu (Nanjing University of Aeronautics and Astronautics); Wang, Yue (George Mason University); Tian, Zhi (George Mason University); Leus, G.J.T. (TU Delft Signal Processing Systems); Zhang, Gong (Nanjing University of Aeronautics and Astronautics)","","2023","This paper proposes a super-resolution harmonic retrieval method for uncorrelated strictly non-circular signals, whose covariance and pseudo-covariance present Toeplitz and Hankel structures, respectively. Accordingly, the augmented covariance matrix constructed by the covariance and pseudo-covariance matrices is not only low rank but also jointly Toeplitz-Hankel structured. To efficiently exploit such a desired structure for high estimation accuracy, we develop a low-rank Toeplitz-Hankel covariance reconstruction (LRTHCR) solution employed over the augmented covariance matrix. Further, we design a fitting error constraint to flexibly implement the LRTHCR algorithm without knowing the noise statistics. In addition, performance analysis is provided for the proposed LRTHCR in practical settings. Simulation results reveal that the LRTHCR outperforms the benchmark methods in terms of lower estimation errors.","low-rank Toeplitz-Hankel covariance reconstruction; harmonic retrieval; non-circularity; augmented covariance","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-05","","","Signal Processing Systems","","",""
"uuid:c6c8bea0-6b66-4e76-b5e7-36ab749624af","http://resolver.tudelft.nl/uuid:c6c8bea0-6b66-4e76-b5e7-36ab749624af","Slot-VAE: Object-Centric Scene Generation with Slot Attention","Wang, Y. (TU Delft Signal Processing Systems); Liu, Letao (Nanyang Technological University); Dauwels, J.H.G. (TU Delft Signal Processing Systems)","","2023","Slot attention has shown remarkable object-centric representation learning performance in computer vision tasks without requiring any supervision. Despite its object-centric binding ability brought by compositional modelling, as a deterministic module, slot attention lacks the ability to generate novel scenes. In this paper, we propose the Slot-VAE, a generative model that integrates slot attention with the hierarchical VAE framework for object-centric structured scene generation. For each image, the model simultaneously infers a global scene representation to capture high-level scene structure and object-centric slot representations to embed individual object components. During generation, slot representations are generated from the global scene representation to ensure coherent scene structures. Our extensive evaluation of the scene generation ability indicates that Slot-VAE outperforms slot representation-based generative baselines in terms of sample quality and scene structure accuracy.","","en","journal article","","","","","","","","","","","Signal Processing Systems","","",""
"uuid:dddc7853-8bfe-41f1-abdf-610a9b73967d","http://resolver.tudelft.nl/uuid:dddc7853-8bfe-41f1-abdf-610a9b73967d","Technologies in Long-Term Care and Nursing Homes","Wang, Gubing (Tilburg University); Albayrak, A. (TU Delft Applied Ergonomics and Design); Mattace-Raso, Francesco (Erasmus MC); van der Cammen, T.J.M. (TU Delft Applied Ergonomics and Design)","Pilotto, Alberto (editor); Maetzler, Walter (editor)","2023","Long-term care is defined as a variety of services designed to meet a person’s health and personal care needs which help people live as independently and safely as possible when they can no longer perform everyday activities on their own. Depending on the needs and social context of the patient, long-term care can be provided in different places by different kinds of formal or informal caregivers, either at home or in an institutionalised setting, which from here on we will refer to as the nursing home. In all these fields, technology has an increasing role to play.","Caregivers; Dementia care; Falls management; Integrated care; Older adults; Technologies","en","book chapter","Springer Nature","","","","","","","2024-01-22","","","Applied Ergonomics and Design","","",""
"uuid:89517b06-0356-41c2-a01f-06aa80335777","http://resolver.tudelft.nl/uuid:89517b06-0356-41c2-a01f-06aa80335777","Deep learning-based design model for suction caissons on clay","Yin, Xilin (Student TU Delft); Wang, H. (TU Delft Geo-engineering; Norwegian Geotechnical Institute); Pisano, F. (TU Delft Geo-engineering); Gavin, Kenneth (TU Delft Geo-engineering); Askarinejad, A. (TU Delft Geo-engineering); Zhou, Hongpeng (The University of Manchetser)","","2023","Predicting the non-linear loading response is the key to the design of suction caissons. This paper presents a systematic study to explore the applicability of deep learning techniques in foundation design. Firstly, a series of three-dimensional finite element simulations was performed, covering a wide range of embedment ratios and different loading directions, to provide training data for the deep neural network (DNN) model. Then, hyper-parameter tuning was performed and it is found that the basic Fully-Connected (FC) neural network model is sufficient to capture the non-linear response of suction caissons with excellent accuracy and robustness. Furthermore, the optimized FC neural network model was also successfully applied to a database of suction caissons in sand, demonstrating its broad applicability. By comparing three typical DNNs, i.e., FC, Convolutional Neural Network (CNN) and Long Short-Term Memory (LSTM), it was observed that the FC neural network model excels over others in terms of simplicity, efficiency and accuracy. More importantly, by looking into the model's generalization performance, the FC neural network model can also identify the change in foundation failure mechanisms. This study demonstrates the DNN's powerful mapping ability and its potential for future use in offshore foundation design.","Caisson foundation; Deep learning; Load–displacement relationship; Numerical modelling","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:ab8c092f-90fa-4010-99a2-15633722ac36","http://resolver.tudelft.nl/uuid:ab8c092f-90fa-4010-99a2-15633722ac36","Fusion of Gaze and Scene Information for Driving Behaviour Recognition: A Graph-Neural-Network- Based Framework","Yi, Yangtian (Beijing Institute of Technology); Lu, Chao (Beijing Institute of Technology); Wang, Boyang (Beijing Institute of Technology); Cheng, Long (Southeast University); Li, Z. (TU Delft Transport and Planning; Beijing Institute of Technology); Gong, Jianwei (Beijing Institute of Technology)","","2023","Accurate recognition of driver behaviours is the basis for a reliable driver assistance system. This paper proposes a novel fusion framework for driver behaviour recognition that utilises the traffic scene and driver gaze information. The proposed framework is based on the graph neural network (GNN) and contains three modules, namely, the gaze analysing (GA) module, scene understanding (SU) module and the information fusion (IF) module. The GA module is used to obtain gaze images of drivers, and extract the gaze features from the images. The SU module provides trajectory predictions for surrounding vehicles, motorcycles, bicycles and other traffic participants. The GA and SU modules are parallel and the outputs of both modules are sent to the IF module that fuses the gaze and scene information using the attention mechanism and recognises the driving behaviours through a combined classifier. The proposed framework is verified on a naturalistic driving dataset. The comparative experiments with the state-of-the-art methods demonstrate that the proposed framework has superior performance for driving behaviour recognition in various situations.","data fusion; Driving behaviours; gaze information; graph neural network; scene information","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-12","","","Transport and Planning","","",""
"uuid:c5fb5459-968a-433b-96be-f9481535857e","http://resolver.tudelft.nl/uuid:c5fb5459-968a-433b-96be-f9481535857e","MXene Chemistry and Applications","Sofer, Zdenek (University of Chemistry and Technology Prague); Wang, Xuehang (TU Delft RST/Storage of Electrochemical Energy); Yu, Minghao (Technische Universität Dresden)","","2023","","","en","contribution to periodical","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-01","","","RST/Storage of Electrochemical Energy","","",""
"uuid:bc960f8a-41df-4f27-a4f1-7c9b9d601ee5","http://resolver.tudelft.nl/uuid:bc960f8a-41df-4f27-a4f1-7c9b9d601ee5","FABRIC: Fast and secure unbounded cross-system encrypted data sharing in cloud computing","Wang, Lili (University of Electronic Science and Technology of China; Network and Data Security Key Laboratory of Sichuan Province); Lin, Ye (University of Electronic Science and Technology of China; Network and Data Security Key Laboratory of Sichuan Province); Yao, Ting (University of Electronic Science and Technology of China; Network and Data Security Key Laboratory of Sichuan Province); Xiong, Hu (University of Electronic Science and Technology of China; Network and Data Security Key Laboratory of Sichuan Province); Liang, K. (TU Delft Cyber Security)","","2023","Existing proxy re-encryption (PRE) schemes to secure cloud data sharing raise challenges such as supporting the heterogeneous system efficiently and achieving the unbounded feature. To address this problem, we proposed a fast and secure unbounded cross-domain proxy re-encryption scheme, named FABRIC, which enables the delegator to authorize the semi-trusted cloud server to convert one ciphertext of an identity-based encryption (IBE) scheme to another ciphertext of an attribute-based encryption (ABE) scheme. As the first scheme to achieve the feature mentioned above, FABRIC not only enjoys constant computation overhead in the encryption, decryption, and re-encryption phases when the quantity of attributes increases, but is also unbounded such that the new attributes or roles could be adopted into the system anytime. Furthermore, FABRIC achieves adaptive security under the decisional linear assumption (DLIN). Eventually, detailed theoretical and experimental analysis proved that FABRIC enjoys excellent performance in efficiency and practicality in the cloud computing scenario.","Cross-domain data sharing; Encrypted data sharing; Cloud computing; Security; Privacy","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-12-04","","","Cyber Security","","",""
"uuid:5c51ff10-45c3-4235-9d2a-59da0a02e967","http://resolver.tudelft.nl/uuid:5c51ff10-45c3-4235-9d2a-59da0a02e967","Author Correction: Quantification of the Li-ion diffusion over an interface coating in all-solid-state batteries via NMR measurements (Nature Communications, (2021), 12, 1, (5943), 10.1038/s41467-021-26190-2)","Liu, M. (TU Delft RST/Storage of Electrochemical Energy); Wang, C. (TU Delft RST/Storage of Electrochemical Energy); Zhao, C. (TU Delft RST/Storage of Electrochemical Energy; Tsinghua University); van der Maas, E.L. (TU Delft RST/Storage of Electrochemical Energy); Lin, Kui (Tsinghua University); Arszelewska, Violetta (TU Delft RST/Storage of Electrochemical Energy); Li, Baohua (Tsinghua University); Ganapathy, S. (TU Delft RID/TS/Instrumenten groep); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2023","The original version of this article contained errors in Figure 3a and Figure 3f. In Figure 3a, the activation energies (Ea) were calculated using a log scale instead of a logarithm ln scale. In Figure 3f, the y-axis interval was not properly selected. The correct y-axis interval in Figure 3f and the numerical values of the activation energy are now provided in Figure 3a and the main text. These errors have been corrected in the HTML and PDF versions of the article.","","en","journal article","","","","","","Corrections & amendments DOI 10.1038/s41467-021-26190-2","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:b16f042c-06ef-4b71-84ea-f266c42e4ee2","http://resolver.tudelft.nl/uuid:b16f042c-06ef-4b71-84ea-f266c42e4ee2","Erratum: Electrical characteristics and photodetection mechanism of TiO2/AlGaN/GaN heterostructure-based ultraviolet detectors with a Schottky junction (J. Mater. Chem. C (2023) 11 (1704–1713) DOI: 10.1039/D2TC04491A)","Zhan, Teng (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Sun, Jianwen (Tsinghua University); Feng, Tao (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Zhang, Yulong (Tsinghua University); Zhou, Binru (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Zhang, Banghong (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Wang, Junxi (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Sarro, Pasqualina M (TU Delft Electronic Components, Technology and Materials); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2023","The authors regret an error in the abstract of the published article: the text ‘‘(i) the Schottky emission mechanism at a low reverse voltage (0–1 V) before the current is fully turned on.’’ should be changed to ‘‘(i) the Schottky emission mechanism at a low reverse voltage (0 to 1 V) before the current is fully turned on.’’ This change does not affect the main conclusions of the manuscript. The authors would like to apologize for any inconvenience caused. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.","","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:220ce886-dbc1-4131-8438-f077e11b3544","http://resolver.tudelft.nl/uuid:220ce886-dbc1-4131-8438-f077e11b3544","Taming Irregular Cardiac Signals for Biometric Identification","Wang, Weizheng (TU Delft Embedded Systems); Wang, Q. (TU Delft Embedded Systems); Zuniga, Marco (TU Delft Networked Systems)","","2023","Cardiac patterns are being used to provide hard-to-forge biometric signatures in identification applications. However, this performance is obtained under controlled scenarios where cardiac signals maintain a relatively uniform pattern, facilitating the identification process. In this work, we analyze cardiac signals collected in more realistic (uncontrolled) scenarios and show that their high signal variability makes them harder to obtain stable and distinct features. When faced with these irregular signals, the state-of-the-art (SOTA) reduces its performance significantly. To solve these problems, we propose the CardioID framework1 with two novel properties. First, we design an adaptive method that achieves stable and distinct features by tailoring the filtering process according to each user’s heart rate. Second, we show that users can have multiple cardiac morphologies, offering us a bigger pool of cardiac signals compared to the SOTA. Considering three uncontrolled datasets, our evaluation shows two main insights. First, while using a PPG sensor with healthy individuals, the SOTA’s balanced accuracy (BAC) reduces from 90–95% to 75–80%, while our method maintains a BAC above 90%. Second, under more challenging conditions (using smartphone cameras or monitoring unhealthy individuals), the SOTA’s BAC reduces to values between 65–75%, and our method increases the BAC to values between 75–85%.","authentication; biometric identification; Irregular cardiac signals; uncontrolled scenarios","en","journal article","","","","","","","","","","","Embedded Systems","","",""
"uuid:3631b057-6e20-470a-acec-ceb3476a1137","http://resolver.tudelft.nl/uuid:3631b057-6e20-470a-acec-ceb3476a1137","3ET: Efficient Event-based Eye Tracking using a Change-Based ConvLSTM Network","Chen, Qinyu (University of Zürich; ETH Zürich); Wang, Zuowen (University of Zürich; ETH Zürich); Liu, Shih Chii (University of Zürich; ETH Zürich); Gao, C. (TU Delft Electronics)","","2023","This paper presents a sparse Change-Based Convolutional Long Short-Term Memory (CB-ConvLSTM) model for event-based eye tracking, key for next-generation wearable healthcare technology such as AR/VR headsets. We leverage the benefits of retina-inspired event cameras, namely their low-latency response and sparse output event stream, over traditional frame-based cameras. Our CB-ConvLSTM architecture efficiently extracts spatio-temporal features for pupil tracking from the event stream, outperforming conventional CNN structures. Utilizing a delta-encoded recurrent path enhancing activation sparsity, CB-ConvLSTM reduces arithmetic operations by approximately 4.7× without losing accuracy when tested on a v2e-generated event dataset of labeled pupils. This increase in efficiency makes it ideal for real-time eye tracking in resource-constrained devices. The project code and dataset are openly available at https://github.com/qinche106/cb-convlstm-eyetracking.","Pupil tracking; event cameras; sparsity; ConvLSTM; healthcare; AR/VR","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-18","","","Electronics","","",""
"uuid:59595d36-d099-4358-ad54-6d4111e7032b","http://resolver.tudelft.nl/uuid:59595d36-d099-4358-ad54-6d4111e7032b","Blockchain for regenerative built environment governance","Wang, Hongyang (ETH Zürich); Hunhevicz, Jens (ETH Zürich; Swiss Federal Laboratories for Materials Science and Technology (Empa)); Hall, Daniel M. (TU Delft Design & Construction Management); Meier, Gregor (ETH Zürich); De Wolf, Catherine (ETH Zürich)","","2023","Regenerative approaches have gained attention in the built environment, but remain highly conceptual. This position paper argues for new regenerative governance structures that consider data governance, reassess complex stakeholder interactions, and ensure the inclusivity of diverse values and ownership. It then presents early ideas on how blockchain technology could facilitate scalable socio-economic-ecologic interactions along three inquiries, giving practical examples. Overall, the paper aims to inspire and guide further research into the development of modern digital governance tools fostering a regenerative built environment.","","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:a1f1579b-a821-4a59-a581-90f64696b63c","http://resolver.tudelft.nl/uuid:a1f1579b-a821-4a59-a581-90f64696b63c","Controller Placement with Respect to Controller Reachability","Xu, Ran (Student TU Delft); Wang, F. (TU Delft Network Architectures and Services); Kooij, Robert (TU Delft Quantum & Computer Engineering; TNO)","","2023","In this paper we investigate the controller placement problem on networks using controller reachability as the network performance metric. This metric is defined as the probability that each node can reach at least one controller, given that each link is operational with a fixed probability. By exploring placements for more than 100 real-world networks and by varying the number of controllers from two to five, we find that controller reachability varies greatly with different placements. Obviously, increasing the number of controllers increases the controller reachability. However, the extent of this increase depends on the strategy with which the controllers are placed. The findings indicate that efficient controller placement strategies should be developed to ensure good network performance. In this research, we propose four controller placement strategies. One strategy is based on topological network metrics: node degree and path length between controllers and nodes. The other three heuristic strategies are the greedy algorithm, the classic genetic algorithm and the heuristic genetic algorithm. By validating strategies on real-world networks, we find that all four strategies work well to solve the controller placement problem with respect to controller reachability.","Controller reachability; controller placement; heuristic algorithms","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-08","","Quantum & Computer Engineering","Network Architectures and Services","","",""
"uuid:131f55c3-4c9c-43ca-9428-8b3b32638335","http://resolver.tudelft.nl/uuid:131f55c3-4c9c-43ca-9428-8b3b32638335","When to Let the Developer Guide: Trade-offs Between Open and Guided Test Amplification","Brandt, C.E. (TU Delft Software Engineering); Wang, D. (Student TU Delft); Zaidman, A.E. (TU Delft Software Engineering)","Moonen, Leon (editor); Newman, Christian (editor); Gorla, Alessandra (editor)","2023","Test amplification generates new tests by mutating existing, developer-written tests and keeping those tests that improve the coverage of the test suite. Current amplification tools focus on starting from a specific test and propose coverage improvements all over a software project, requiring considerable effort from the software engineer to understand and evaluate the different tests when deciding whether to include a test in the maintained test suite. In this paper, we propose a novel approach that lets the developer take charge and guide the test amplification process towards a specific branch they would like to test in a control flow graph visualization. We evaluate whether simple modifications to the automatic process that incorporate the guidance make the test amplification more effective at covering targeted branches. In a user study and semi-structured interviews we compare our user-guided test amplification approach to the state-of-the-art open test amplification approach. While our participants prefer the guided approach, we uncover several trade-offs that influence which approach is the better choice, largely depending on the use case of the developer.","Software Testing; Test Amplification; Automated Test Code Modification; User-centric Design; Human-Automation Interaction","en","conference paper","IEEE Computer Society - Conference Publishing Services","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-01","","","Software Engineering","","",""
"uuid:39e62c96-d1d9-4882-a003-6b3b8398a7c5","http://resolver.tudelft.nl/uuid:39e62c96-d1d9-4882-a003-6b3b8398a7c5","Estimating intercity heavy truck mobility flows using the deep gravity framework","Yang, Y. (TU Delft Transport and Planning; Beijing Jiaotong University); Jia, Bin (Beijing Jiaotong University; Xi'an Technological University); Yan, Xiao Yong (Beijing Jiaotong University); Chen, Yan (Beijing Jiaotong University); Song, Dongdong (Beijing Jiaotong University); Zhi, Danyue (Beijing Jiaotong University); Wang, Y. (TU Delft Transport and Planning; Ministry of Education, Shanghai); Gao, Ziyou (Beijing Jiaotong University)","","2023","Accurate estimation of intercity heavy truck mobility flows is of vital importance to urban planning, transportation management and logistics operations. The inaccessibility of big data related to intercity transport systems and the heterogeneity of trucking activities pose challenges for the reliable estimation. Recently, the advance of Artificial Intelligence (AI) provides a potential solution to this problem. However, most previous studies focused on the estimation of inter-regional passenger mobility. In-depth studies of estimating intercity heavy truck mobility flows by using deep learning techniques are still scarce. To fill in the gaps, we construct a deep neural network based on the Deep Gravity framework, an advanced predictive model for human mobility. We collect a wide range of data related to heavy truck movements, freight locations, road networks and land uses to train the model, and validate its high performance by comparing to traditional gravity model. Furthermore, we use an explainable AI technique to interpret how the city features contribute to the determination of intercity heavy truck movements, and the results can provide valuable policy implications for logistics operations, businesses and urban planning.","Deep gravity framework; Deep neural network; Heavy trucks; Intercity mobility","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-10","","","Transport and Planning","","",""
"uuid:b2f08b8d-ee04-4ce7-aa39-423d728af097","http://resolver.tudelft.nl/uuid:b2f08b8d-ee04-4ce7-aa39-423d728af097","Subgap spectroscopy along hybrid nanowires by nm-thick tunnel barriers","Levajac, V. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech); Wang, Ji Yin (Kavli institute of nanoscience Delft; QuTech; Beijing Academy of Quantum Information Sciences, Beijing); Sfiligoj, C. (TU Delft BUS/Quantum Delft; Kavli institute of nanoscience Delft; QuTech); Lemang, M.F. (TU Delft QN/Afdelingsbureau; Kavli institute of nanoscience Delft; QuTech); Wolff, J.C. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech); Bordin, A. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech); Badawy, G.H.A. (Eindhoven University of Technology); Gazibegovic, Sasa (Eindhoven University of Technology); Bakkers, Erik P.A.M. (Eindhoven University of Technology); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech)","","2023","Tunneling spectroscopy is widely used to examine the subgap spectra in semiconductor-superconductor nanostructures when searching for Majorana zero modes (MZMs). Typically, semiconductor sections controlled by local gates at the ends of hybrids serve as tunnel barriers. Besides detecting states only at the hybrid ends, such gate-defined tunnel probes can cause the formation of non-topological subgap states that mimic MZMs. Here, we develop an alternative type of tunnel probes to overcome these limitations. After the growth of an InSb-Al hybrid nanowire, a precisely controlled in-situ oxidation of the Al shell is performed to yield a nm-thick AlOx layer. In such thin isolating layer, tunnel probes can be arbitrarily defined at any position along the hybrid nanowire by shadow-wall angle-deposition of metallic leads. In this work, we make multiple tunnel probes along single nanowire hybrids and successfully identify Andreev bound states (ABSs) of various spatial extension residing along the hybrids.","","en","journal article","","","","","","","","","","","QRD/Kouwenhoven Lab","","",""
"uuid:532af9e5-dc99-4cd3-9c96-c5a10f809b03","http://resolver.tudelft.nl/uuid:532af9e5-dc99-4cd3-9c96-c5a10f809b03","Uncertainty-Encoded Multi-Modal Fusion for Robust Object Detection in Autonomous Driving","Lou, Yang (City University of Hong Kong); Song, Q. (TU Delft Embedded Systems); Xu, Qian (City University of Hong Kong); Tan, Rui (Nanyang Technological University); Wang, J. (TU Delft Microwave Sensing, Signals & Systems; City University of Hong Kong)","Gal, Kobi (editor); Gal, Kobi (editor); Nowe, Ann (editor); Nalepa, Grzegorz J. (editor); Fairstein, Roy (editor); Radulescu, Roxana (editor)","2023","Multi-modal fusion has shown initial promising results for object detection of autonomous driving perception. However, many existing fusion schemes do not consider the quality of each fusion input and may suffer from adverse conditions on one or more sensors. While predictive uncertainty has been applied to characterize single-modal object detection performance at run time, incorporating uncertainties into the multi-modal fusion still lacks effective solutions due primarily to the uncertainty's cross-modal incomparability and distinct sensitivities to various adverse conditions. To fill this gap, this paper proposes Uncertainty-Encoded Mixture-of-Experts (UMoE) that explicitly incorporates single-modal uncertainties into LiDAR-camera fusion. UMoE uses individual expert network to process each sensor's detection result together with encoded uncertainty. Then, the expert networks' outputs are analyzed by a gating network to determine the fusion weights. The proposed UMoE module can be integrated into any proposal fusion pipeline. Evaluation shows that UMoE achieves a maximum of 10.67%, 3.17%, and 5.40% performance gain compared with the state-of-the-art proposal-level multi-modal object detectors under extreme weather, adversarial, and blinding attack scenarios.","","en","conference paper","IOS Press","","","","","","","","","","Embedded Systems","","",""
"uuid:0751d93e-5981-4a2e-b89d-7c3958fb39ca","http://resolver.tudelft.nl/uuid:0751d93e-5981-4a2e-b89d-7c3958fb39ca","Condensation du NH3 / H2O avec des concentrations massiques entre 80% et 96%: étude expérimentale dans un échangeur de chaleur à plaque","Toa, X. (TU Delft Engineering Thermodynamics; Hangzhou City University); Shen, Yunwei (Hangzhou City University); Wang, Bo (Hangzhou City University); Infante Ferreira, C.A. (TU Delft Engineering Thermodynamics)","","2023","High concentration NH3/H2O is suitable for Kalina cycles used for the recovery of low grade heat. Plate heat exchangers (PHEs) are compact and reduce the charge of working fluid. This paper investigates the condensation of NH3/H2O with NH3 mass concentrations of 80%-96%. The vapor and liquid concentrations are close to equilibrium state, which are different from normal absorbers. The apparent heat transfer coefficients (HTCs) and frictional pressure drop are presented, covering the mass fluxes of 32–86 kgm−2s−1, the averaged vapor qualities of 0.08–0.65 and the saturated pressure of 610 to 780 kPa. Larger mass fluxes noticeably increase the apparent HTCs and frictional pressure drop. At the mass concentrations of 96%, 91% and 88%, higher vapor qualities increase the apparent HTCs for large mass fluxes. The apparent HTCs decrease slightly with vapor qualities for 80% mass concentration. The experimental results are compared with those of pure NH3. The flow patterns of high concentration NH3/H2O are considered as full film flow and partial film flow, which are the same as for NH3. The mass transfer resistance deteriorates the heat transfer especially for partial film flow, which happens at small liquid mass fluxes. The mass transfer resistance has negligible influences on frictional pressure drop.","Absorption; Condensation heat transfer; Experimental investigation; NH /HO; Plate heat exchanger; Two-phase frictional pressure drop","fr","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-07","","","Engineering Thermodynamics","","",""
"uuid:b2017133-5e97-492f-bbf9-636f59f93e8d","http://resolver.tudelft.nl/uuid:b2017133-5e97-492f-bbf9-636f59f93e8d","Characterizing Behavioral Differences of Autonomous Vehicles and Human-Driven Vehicles at Signalized Intersections Based on Waymo Open Dataset","Wang, Y. (TU Delft Transport and Planning; Tongji University; Ministry of Education, Shanghai); Farah, H. (TU Delft Transport and Planning); Yu, Rongjie (Tongji University; Ministry of Education, Shanghai); Qiu, Shuhan (Tongji University; Ministry of Education, Shanghai); van Arem, B. (TU Delft Transport and Planning)","","2023","Autonomous vehicles (AVs) are being introduced to the traffic system with the promise of improving current traffic status. However, the empirical data also indicate contrary effects with estimated higher crash rate and change of crash patterns. Therefore, it is necessary to investigate the driving behavior of AVs and human-driven vehicles (HDVs) in real mixed traffic. Current studies have analyzed the driving behavior of AVs and HDVs, as well as behavioral adaptations of drivers of HDVs based on empirical data. While they play an important role in traffic systems, signalized intersections have not been studied sufficiently in this context. Therefore, this study aims to utilize the Waymo open dataset to characterize and quantify the behavioral differences of AVs and HDVs at signalized intersections. Five parameters of driving behavior related to signalized intersections were characterized according to five critical maneuver phases, which were identified by wavelet transform and threshold-based method. Statistically significant differences in driving behavior between AVs and HDVs were found, from three categorized situations: vehicle approaching the red light/queue, vehicle responding to the green light (as the first vehicle), and vehicle responding to its preceding vehicle (in the queue). Further, behavioral adaptations of HDV drivers were revealed in that they tended to keep closer to the stopped AVs in a queue and to react more strongly to AV start-up maneuvers when the traffic light turns to green.","automated/autonomous vehicles; operations; traffic flow; traffic flow theory and characteristics","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-04","","","Transport and Planning","","",""
"uuid:c6fd4b90-905f-4c29-b066-1a8ed46f9c56","http://resolver.tudelft.nl/uuid:c6fd4b90-905f-4c29-b066-1a8ed46f9c56","Electrical operation of planar Ge hole spin qubits in an in-plane magnetic field","Sarkar, Abhikbrata (University of New South Wales); Wang, Zhanning (University of New South Wales); Rendell, Matthew (University of New South Wales); Hendrickx, N.W. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Veldhorst, M. (TU Delft QN/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Scappucci, G. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Khalifa, Mohammad (University of British Columbia); Salfi, Joe (University of British Columbia); Saraiva, Andre (University of New South Wales)","","2023","Hole spin qubits in group-IV semiconductors, especially Ge and Si, are actively investigated as platforms for ultrafast electrical spin manipulation thanks to their strong spin-orbit coupling. Nevertheless, the theoretical understanding of spin dynamics in these systems is in the early stages of development, particularly for in-plane magnetic fields as used in the vast majority of experiments. In this work, we present a comprehensive theory of spin physics in planar Ge hole quantum dots in an in-plane magnetic field, where the orbital terms play a dominant role in qubit physics, and provide a brief comparison with experimental measurements of the angular dependence of electrically driven spin resonance. We focus the theoretical analysis on electrical spin operation, phonon-induced relaxation, and the existence of coherence sweet spots. We find that the choice of magnetic field orientation makes a substantial difference for the properties of hole spin qubits. Specifically, we find that (i) EDSR for in-plane magnetic fields varies nonlinearly with the field strength and weaker than for perpendicular magnetic fields. (ii) The EDSR Rabi frequency is maximized when the a.c. electric field is aligned parallel to the magnetic field, and vanishes when the two are perpendicular. (iii) The orbital magnetic field terms make the in-plane g-factor strongly anisotropic in a squeezed dot, in excellent agreement with experimental measurements. (iv) Focusing on random telegraph noise, we show that the effect of noise in an in-plane magnetic field cannot be fully mitigated, as the orbital magnetic field terms expose the qubit to all components of the defect electric field. These findings will provide a guideline for experiments to design ultrafast, highly coherent hole spin qubits in Ge.","","en","journal article","","","","","","","","","","","QCD/Veldhorst Lab","","",""
"uuid:397620a8-d62f-4a0b-95f0-0e68ceebfa9e","http://resolver.tudelft.nl/uuid:397620a8-d62f-4a0b-95f0-0e68ceebfa9e","The magnitudes of multi-physics effects on geothermal reservoir characteristics during the production of enhanced geothermal system","Song, G. (TU Delft Applied Geology); Shi, Yu (Southwest Jiaotong University); Xu, Fuqiang (China University of Petroleum - Beijing); Song, Xianzhi (China University of Petroleum - Beijing); Li, Gensheng (China University of Petroleum - Beijing); Wang, Gaosheng (China University of Petroleum - Beijing); Lv, Zehao (Petrochina Research Institute of Petroleum Exploration and Development)","","2023","The multi-physics coupling process during the heat extraction from enhanced geothermal system, encompassing thermo(T)-hydro(H)-mechanical(M)-chemical(C) interactions, plays a pivotal role in changing geothermal reservoir characteristics. However, a comprehensive quantitative assessment of these multi-physics behaviors has been lacking. In this study, a novel approach was proposed to calculate the magnitude of mechanical, chemical, strong mechanical-chemical coupling, and weak mechanical-chemical coupling effects on the variations of reservoir characteristics. In particular, mechanical-chemical coupling effects are quantified for the first time. They are obtained by the fracture aperture difference results across five distinct coupling models (thermo-hydro, thermo-hydro-chemical, thermo-hydro-mechanical, partially-coupled four-field, and fully-coupled four-field models). The findings indicate that mechanical effects lead to an increase in fracture aperture, while chemical effects contribute to its reduction under underbalanced injection conditions. Strong mechanical-chemical coupling effects, exhibiting a negative correlation with chemical effects, conversely result in a diminished fracture aperture. The influences of these effects are investigated from the temporal and spatial perspectives. Temporally, mechanical effects dominate early production while chemical effects become prominent in later stages. Spatially, there mainly exists two zones when stable production: a mechanical-controlled region surrounding injection wells, and a chemical-controlled area distant from the injection wells. Furthermore, sensitivity analysis of injection concentration indicates its alternation changes the reservoir traits and production performance by modifying the magnitudes of chemical and mechanical-chemical coupling effects. This quantification of multi-physics effects offers insights into optimizing injection strategies for better geothermal development. The approach could hold promising potential in other geo-energy scenarios like carbon and hydrogen storage in reservoirs.","Fracture aperture; Geothermal; Multi-physics effect; Quantitative evaluation; Thermo-hydro-mechanical-chemical coupling","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-12","","","Applied Geology","","",""
"uuid:cf959901-933c-4f1e-85da-0876373a573c","http://resolver.tudelft.nl/uuid:cf959901-933c-4f1e-85da-0876373a573c","Policy-based initiatives on promoting China's affordable housing: Challenges and opportunities","Zhang, Guoqiang (Hunan University); Xu, Keyi (Hunan University); Liu, Zhengxuan (TU Delft Design & Construction Management); Huang, R. (TU Delft Design & Construction Management; Chongqing University); Li, B. (TU Delft Real Estate Management); Wang, Ran (Hunan University)","","2023","The construction industry's commitment to achieving carbon neutrality has underscored the urgency of promoting green and low-carbon sustainable affordable housing. However, the development process has encountered several challenges, including conflicts between the central and local governments arising from differences in value preferences, financial constraints faced by local governments, inadequate access mechanisms, lenient screening processes, insufficient funding, and remote locations. Despite its significance, the policies related to affordable housing, especially in the context of assembly affordable housing, have received limited systematic examination. To address this research gap, this paper presents a comprehensive review and analysis of China's affordable housing policies. Firstly, it compiles and compares recent affordable housing policies in China, serving as a valuable reference for future affordable housing construction endeavors. Secondly, it conducts an in-depth analysis of the barriers and challenges obstructing affordable housing development in China, and proposing corresponding measures for improvement. Moreover, this paper identifies significant opportunities for affordable housing development in the country and explores the potential synergy between the development of assembly buildings and affordable housing by leveraging their respective attributes. By illuminating pertinent policies and associated issues, this research aims to inform policymakers, practitioners, and stakeholders involved in the affordable housing sector. Additionally, it aims to stimulate further research and innovation in the field, contributing to effective and sustainable housing solutions for low-income communities and society at large. This paper systematically analyzes the current status of affordable housing policies, challenges and opportunities. It also discusses the application of assembly building techniques in the realm of affordable housing, proving valuable insights to address traditional housing issues.","Affordable housing; Assembly building; Low carbon; Policy incentive; Sustainable housing","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:31083173-787e-4bfd-bcb4-31a3ee69858e","http://resolver.tudelft.nl/uuid:31083173-787e-4bfd-bcb4-31a3ee69858e","2nd Workshop on Multimodal Motion Sickness Detection and Mitigation Methods for Car Journeys - Finding Consensus in the Field","Pöhlmann, Katharina Margareta Theresa (University of Glasgow; KITE-Toronto Rehabilitation Institute); Al Taie, Ammar Jamal Said (University of Glasgow); Li, Gang (University of Glasgow); Dam, Abhraneil (Virginia Tech); Wang, Yu Kai (University of Technology Sydney); Wei, Chun Shu (National Yang Ming Chiao Tung University); Papaioannou, G. (TU Delft Intelligent Vehicles)","","2023","The adoption of automated vehicles will be a positive step towards road safety and environmental benefits. However, one major challenge that still exist is motion sickness. The move from drivers to passengers who will engage in non-driving related tasks as well as the potential change in the layout of the car interior that will come with automated vehicles are expected to result in a worsened experience of motion sickness. The previous workshop [18] highlighted the need for consensus on guidelines regarding study design for motion sickness research. Hence, this workshop will develop a guide for motion sickness research through reflection and discussions on the current methodologies used by experts in the field. Further it will build on the knowledge collected from the previous workshop and will thereby facilitate not only new research ideas and fruitful collaborations but also find a consensus in the field in regard to study design and methodologies.","Automated Vehicles; Comfort; Detection; Mitigation; Motion Sickness","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Intelligent Vehicles","","",""
"uuid:a07ff354-3da9-4e83-9a46-3b246736232e","http://resolver.tudelft.nl/uuid:a07ff354-3da9-4e83-9a46-3b246736232e","Effects of GBFS content and curing methods on the working performance and microstructure of ternary geopolymers based on high-content steel slag","Yang, Xinkui (Wuhan University of Technology); Wu, Shaopeng (Wuhan University of Technology); Xu, S. (TU Delft Materials and Environment; Wuhan University of Technology); Chen, B. (TU Delft Materials and Environment); Chen, Dongyu (Wuhan University of Technology); Wang, Fusong (Huazhong University of Science and Technology); Jiang, Jian (Shenzhen Sez Construction Group Co., Ltd.); Fan, Lulu (Shenzhen Sez Construction Group Co., Ltd.); Tu, Liangliang (Shenzhen Sez Construction Group Co., Ltd.)","","2023","Aimed to address the low utilization rate of steel slag (SS) and its challenge in resource utilization in China, this study developed ternary geopolymers made by high-content (50%) SS together with fly ash (FA) and granulated blast furnace slag (GBFS). The effects of GBFS content (0–40%) and curing methods (water curing, standard curing, sealed curing, and heat curing) on the working performance and microstructure of geopolymers were investigated. Microscopic analysis such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG-DTG), and scanning electron microscopy (SEM) were utilized to investigate the hydration process and products of geopolymers under different curing conditions and GBFS content. The results indicated that when the GBFS content increased from 0% to 40%, the fluidity of the mixture decreased by 11.7%, the initial setting time of the geopolymer slurry decreased by 76%, and the geopolymer mortar's 28d compressive strength increased from 31.9 MPa to 60.6 MPa. At room temperature, the geopolymer mortar's 28d compressive strength was higher under standard curing (70.8 MPa) compared to water curing (57.5 MPa) and sealed curing (68 MPa). The geopolymer mortar cured at 60 °C for 24 h exhibited the highest 28d compressive strength (76.3 MPa). However, excessively high curing temperatures or prolonged durations led to more shrinkage cracks and reduced the compressive strength. The microscopic analysis revealed that the main gel products of ternary geopolymer were C-(A)-S-H gel. The amount of gel products is directly related to the strength of geopolymers. The developed ternary geopolymer has the potential to promote the large-scale utilization of SS in the concrete industry, making a significant contribution to sustainable development.","Curing methods; Geopolymer; Steel slag; Working performance","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-21","","","Materials and Environment","","",""
"uuid:b9b45940-05c0-4b81-8349-40b54d946bbd","http://resolver.tudelft.nl/uuid:b9b45940-05c0-4b81-8349-40b54d946bbd","Conjugated Polyelectrolyte Thin Films for Pseudocapacitive Applications","Yip, Benjamin Rui Peng (National University of Singapore); Javier Vázquez, Ricardo (National University of Singapore); Jiang, Yan (National University of Singapore); McCuskey, Samantha R. (National University of Singapore; Nanyang Technological University); Quek, Glenn (National University of Singapore); Ohayon, David (National University of Singapore); Wang, Xuehang (TU Delft RST/Storage of Electrochemical Energy); Bazan, Guillermo C. (National University of Singapore; Nanyang Technological University; University of California)","","2023","A subclass of organic semiconductors known as conjugated polyelectrolytes (CPEs) is characterized by a conjugated backbone with ionic pendant groups. The water solubility of CPEs typically hinders applications of thin films in aqueous media. Herein, it is reported that films of an anionic CPE, namely CPE-K, drop cast from water produces single-component solid-state pseudocapacitive electrodes that are insoluble in aqueous electrolyte. That X-ray diffraction experiments reveal a more structurally ordered film, relative to the as-obtained powder from chemical synthesis, and dynamic light scattering measurements show an increase in aggregate particle size with increasing [KCl] indicate that CPE-K films are insoluble because of tight interchain contacts and electrostatic screening by the electrolyte. CPE-K film electrodes can maintain 85% of their original capacitance (84 F g−1) at 500 A g−1 and exhibit excellent cycling stability, where a capacitance retention of 93% after 100 000 cycles at a current density of 35 A g−1. These findings demonstrate that it is possible to use initially water soluble ionic-organic materials in aqueous electrolytes, by increasing the electrolyte concentration. This strategy can be applied to the application of conjugated polyelectrolytes in batteries, organic electrochemical transistors, and electrochemical sensors, where fast electron and ion transport are required.","conjugated polyelectrolytes; cycling stability; high-rate capability; pseudocapacitors","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-28","","","RST/Storage of Electrochemical Energy","","",""
"uuid:44d2ba33-5e5b-473b-a131-6ecb16db9b24","http://resolver.tudelft.nl/uuid:44d2ba33-5e5b-473b-a131-6ecb16db9b24","Effect of Dispersing Solvents for an Ionomer on the Performance of Copper Catalyst Layers for CO2 Electrolysis to Multicarbon Products","Idros, Mohamed Nazmi (University of Queensland); Wu, Yuming (University of Queensland); Duignan, Timothy (University of Queensland); Li, Mengran (TU Delft ChemE/Materials for Energy Conversion and Storage); Cartmill, Hayden (University of Queensland); Maglaya, Irving (University of Queensland); Burdyny, T.E. (TU Delft ChemE/Materials for Energy Conversion and Storage); Wang, Geoff (University of Queensland); Rufford, Thomas E. (University of Queensland)","","2023","To explore the effects of solvent-ionomer interactions in catalyst inks on the structure and performance of Cu catalyst layers (CLs) for CO2 electrolysis, we used a “like for like” rationale to select acetone and methanol as dispersion solvents with a distinct affinity for the ionomer backbone or sulfonated ionic heads, respectively, of the perfluorinated sulfonic acid (PFSA) ionomer Aquivion. First, we characterized the morphology and wettability of Aquivion films drop-cast from acetone- and methanol-based inks on flat Cu foils and glassy carbons. On a flat surface, the ionomer films cast from the Aquivion and acetone mixture were more continuous and hydrophobic than films cast from methanol-based inks. Our study’s second stage compared the performance of Cu nanoparticle CLs prepared with acetone and methanol on gas diffusion electrodes (GDEs) in a flow cell electrolyzer. The effects of the ionomer-solvent interaction led to a more uniform and flooding-tolerant GDE when acetone was the dispersion solvent (acetone-CL) than when we used methanol (methanol-CL). As a result, acetone-CL yielded a higher selectivity for CO2 electrolysis to C2+ products at high current density, up to 25% greater than methanol-CL at 500 mA cm-2. Ethylene was the primary product for both CLs, with a Faradaic efficiency for ethylene of 47.4 ± 4.0% on the acetone-CL and that of 37.6 ± 5.5% on the methanol-CL at a current density of 300 mA cm-2. We attribute the enhanced C2+ selectivity of the acetone-CL to this electrode’s better resistance to electrolyte flooding, with zero seepage observed at tested current densities. Our findings reveal the critical role of solvent-ionomer interaction in determining the film structure and hydrophobicity, providing new insights into the CL design for enhanced multicarbon production in high current densities in CO2 electrolysis processes.","Aquivion conformation; catalyst ink formulation; electrochemical CO reduction; perfluorinated sulfonic acid (PFSA) ionomer; solubility parameter","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-05-06","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:ee2d471b-2b4a-490d-95b8-85b494d7a503","http://resolver.tudelft.nl/uuid:ee2d471b-2b4a-490d-95b8-85b494d7a503","A novel 4H-SiC multiple stepped SGT MOSFET with improved high frequency figure of merit","Zhang, Jingping (Chongqing University); Luo, Houcai (Chongqing University); Wu, Huan (Chongqing University); Wang, Zeping (Chongqing University); Zheng, Bofeng (Chongqing University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Chen, Xianping (Chongqing University)","","2023","A novel 4H-SiC Multiple Stepped SGT MOSFET (MSGT-MOSFET) is presented and investigated utilizing TCAD simulations in this paper. We have quantitatively studied the characteristics of the device through simulation modeling and physical model calculations, and comparatively analyzed the performance and application prospects of this novel device. The gate-to-drain capacitance (Cgd) and gate-to-drain charge (Qgd) of the MSGT-MOSFET are significantly reduced in comparison with the double trench MOSFET (DT-MOSFET) and the conventional SGT MOSFET (CSGT-MOSFET), due to the reduction of the overlapping area of the split gate (SG) structure and drift region. Therefore, the obtained high frequency figure of merit (HF-FOM) defined as [Ron × Cgd] reduced by 23.9% compared with DT-MOSFET and CSGT-MOSFET. And the HF-FOM [Ron × Qgd] for the MSGT-MOSFET significantly decreased by 71% and 50%, respectively, compared to that of the DT-MOSFET and CSGT-MOSFET. Furthermore, the switching loss is also simulated and calculated. And the total switching loss of the proposed MSGT-MOSFET realizes 42.9% and 21.7% reduction in comparison with the DT-MOSFET and CSGT-MOSFET. The overall enhanced performances suggest that the MSGT-MOSFET is an excellent choice for high frequency power electronic applications.","4H-SiC MOSFET; Cgd; HF-FOM; Qgd; SG; switching loss","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-03","","","Electronic Components, Technology and Materials","","",""
"uuid:2590493c-f6ff-49f9-99b2-4930a36b4325","http://resolver.tudelft.nl/uuid:2590493c-f6ff-49f9-99b2-4930a36b4325","Four-flux model combined with optical coherence tomography technique for non-destructive testing of the colour ground layers of the paintings","Wang, X. (TU Delft Structural Integrity & Composites); Anisimov, A. (TU Delft Structural Integrity & Composites); Groves, R.M. (TU Delft Structural Integrity & Composites)","Liang, Haida (editor); Groves, Roger (editor)","2023","The colour of the ground layers of a painting has an influence on its visual appearance. In addition to the commonly used white ground layers, other colour ground layers have been used, for example, the grey ground layer used in Peter Paul Rubens’s painting Portrait of Clara Serena Rubens helps the colour transition of the skin tones. Understanding the effects caused by the colours of the ground layers is of significance for both technical art history and conservation. Optical non-destructive testing (NDT) techniques are useful tools for the investigation of paintings, for example, optical coherence tomography (OCT) can be used to study the surface and subsurface layers non-destructively. In this work, the interaction of light with paint and ground layers is modelled to supplement OCT measurements of paintings with ground layers. A previously described near-infrared light range OCT system provides high spatial and depth resolution measurements. A four-flux model has been developed for analysing the light interaction in the paint and ground layers. This model considers forwards-propagating collimated light, backwards-propagating collimated light, forwards-propagating diffuse light and backwards-propagating diffuse light. The model uses the optical material properties, including refractive index (RI), absorption and layer thickness, as input. This paper describes the construction of the model and an evaluation of its performance by comparison with OCT data.","colour; Four-flux model; ground layer; non-destructive testing; painting","en","conference paper","SPIE","","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:4d5b8bfe-c69b-44f1-86ff-473f3342b9bf","http://resolver.tudelft.nl/uuid:4d5b8bfe-c69b-44f1-86ff-473f3342b9bf","Stiffness profile spectral composition & geometry deterioration of railway tracks","Lu, Tao (Southwest Jiaotong University); Chen, Rong (Southwest Jiaotong University); Wang, Ping (Southwest Jiaotong University); Wu, Junwei (Southwest Jiaotong University); Steenbergen, M.J.M.M. (TU Delft Mechanics and Physics of Structures)","","2023","This work addresses the contribution of the wavelength composition of the spectrum of the rail support stiffness profile to the expected long-term settlement. To that aim, purely harmonic stiffness variations of different wavelength are studied. The frequency-domain model with a double periodicity level previously developed by the first and last authors is adopted to embed the stiffness profile in one of the periodicity layers. Additional resonance velocities at which the resonance frequency of the track system coincides with the support-passing frequency or its multiples are found. The susceptibility to degradation is assessed both by quantifying the mechanical energy dissipated in the substructure under a moving train axle within one wavelength of the support stiffness variation, and the work performed by the wheel-rail contact force. It is shown that shorter wavelengths and larger standard deviations of varying ballast/subgrade stiffness result in an increasing energy dissipation in the substructure, and increase the work performed by the wheel-rail contact force, therefore leading to a reduced lifetime of the track. The energetic quantities increase for lower mean values of the stiffness profile, confirming the proneness of tracks on soft soils to degradation. The influence of varying stiffness vanishes for wavelengths of approximately 16 times the sleeper span, which is equivalent to a track length of about 10 m. High railpad stiffness values result in increased energy dissipation but the influence is limited. In general, an increasing train velocity amplifies the rate of track degradation, with no stabilizing trend in the high-speed regime (300 km/h).","Energy dissipation; Track degradation; Track stiffness; Track stiffness profile; Track stiffness variation","en","journal article","","","","","","","","","","","Mechanics and Physics of Structures","","",""
"uuid:4451192b-c6f8-4fbb-a844-a0c839725e33","http://resolver.tudelft.nl/uuid:4451192b-c6f8-4fbb-a844-a0c839725e33","The recoverability of network controllability with respect to node additions","Wang, F. (TU Delft Network Architectures and Services); Kooij, Robert (TU Delft Quantum & Computer Engineering; TNO)","","2023","Network controllability is a critical attribute of dynamic networked systems. Investigating methods to restore network controllability after network degradation is crucial for enhancing system resilience. In this study, we develop an analytical method based on degree distributions to estimate the minimum fraction of required driver nodes for network controllability under random node additions after the random removal of a subset of nodes. The outcomes of our method closely align with numerical simulation results for both synthetic and real-world networks. Additionally, we compare the efficacy of various node recovery strategies across directed Erdös-Rényi (ER) networks, swarm signaling networks (SSNs), and directed Barabàsi Albert (BA) networks. Our findings indicate that the most efficient recovery strategy for directed ER networks and SSNs is the greedy strategy, which considers node betweenness centrality. Similarly, for directed BA networks, the greedy strategy focusing on node degree centrality emerges as the most efficient. These strategies outperform recovery approaches based on degree centrality or betweenness centrality, as well as the strategy involving random node additions.","network controllability; network resilience; recoverability; recovery strategies","en","journal article","","","","","","","","","","Quantum & Computer Engineering","Network Architectures and Services","","",""
"uuid:d1e5f7b8-c634-4af1-a778-0ae6052bcca5","http://resolver.tudelft.nl/uuid:d1e5f7b8-c634-4af1-a778-0ae6052bcca5","Integrated multimodal freight service network design and pricing with a competing service integrator and heterogeneous shipper classes","Wang, Z. (TU Delft Transport and Logistics; Central South University China); Zhang, Dezhi (Central South University China); Tavasszy, Lorant (TU Delft Transport and Planning; TU Delft Transport and Logistics); Fazi, S. (TU Delft Transport and Logistics)","","2023","In recent years, the highly fragmented multimodal transport offer in several countries has required the integration of these services by logistics service integrators (LSIs). The challenge for LSIs is to set up multimodal transport corridors that can respond efficiently to the heterogeneous demand of shippers and that are cost- and price-competitive against other transport solutions. We develop a bi-level programming model to assess the corridor's pricing and the service network design simultaneously. In the upper level, the model maximizes the profit of the LSI by designing the service network and implementing shipment-based pricing for paths adapted to the heterogeneous demand for transport services. In the lower level, the total cost of shippers in the network who choose services according to their preferences is minimized. We solve the model using reformulation and linearization techniques. Computational experiments based on the real-world case of the New Western Land-Sea Corridor in China are conducted to demonstrate the proposed model and to draw managerial insights. The results show that the shipment-based pricing strategy is beneficial for the LSI to obtain profit increases when considering the shippers’ heterogeneous preferences on time and reliability. The results also revealed that the service design and pricing decisions of the LSI are not only related to operational costs but also depend on the competitors’ offers in the market. Moreover, the impact of the level of frequency discretization, waiting time cost, the penalty cost for not fully utilized services, and the generalized cost of the no-purchase option on the decisions of the LSI are also investigated in the sensitivity analysis.","Heterogeneous preferences; Leader-follower game; Multimodal transport; Service network design; Service pricing","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-03-29","","","Transport and Logistics","","",""
"uuid:6769773e-2195-4998-9af0-698ce848a32f","http://resolver.tudelft.nl/uuid:6769773e-2195-4998-9af0-698ce848a32f","道路沥青挥发性有机化合物减排材料的研究进展","Chang, Xiwen (Wuhan University of Technology); Long, Yongshuang (Wuhan University of Technology); Yi, Mingwei (Wuhan University of Technology; RoadMainT Co., Ltd.); Wang, C. (TU Delft Pavement Engineering); Xiao, Yue (Chang'an University; Wuhan University of Technology)","","2023","Due to the complex organic properties of asphalt materials, the heating process during asphalt pavement construction will lead to the release of asphalt VOCs‧ Asphalt VOCs volatilization will cause irreversible harm to both the environment and health of construction workers‧ Researchers in the field of road construction have carried out extensive research on various emission reduction materials and technologies based on release mechanism of asphalt VOCs‧ There are no comprehensive research and intuitive comparison on emission reduction materials due to the differences between quantitative standards for emission reduction effects‧ This paper summarizes the current research status of asphalt VOCs emission reduction, including the development history of emission reduction technology and reduction mechanism of various asphalt VOCs emission reduction materials mainly based on inhibitors, warm mixing agents and flame retardants‧ In addition, the emission reduction effects of different emission reduction materials are compared and the improvement trend research direction of new and efficient asphalt VOCs reduction technology and materials are proposed to achieve green and low-emission construction‧ Finally, around the environmental protection theme of VOCs emission reduction, this study also put forward the prospect of full life cycle emission mechanism and feasibility of efficient composite materials design to support the urgent need for green transport.","asphalt paving materials; flame retardant; inhibitor; VOCs emission reduction; volatile organic compounds; warm mixing agent; xiaoy@chd.edu.cn","zh","review","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-25","","","Pavement Engineering","","",""
"uuid:6dc462be-9a2c-4674-8ae2-b8774c04326b","http://resolver.tudelft.nl/uuid:6dc462be-9a2c-4674-8ae2-b8774c04326b","PHyL v1.0: A parallel, flexible, and advanced software for hydrological and slope stability modeling at a regional scale","Chen, G. (TU Delft Water Resources; Hohai University); Zhang, Ke (Hohai University); Wang, Sheng (Hohai University); Jia, T. (TU Delft Sanitary Engineering)","","2023","Physically-based hydrological-geotechnical modeling at large scales is difficult, especially due to the time-consuming nature of flow routing and 3D soil stability models. Although parallelization techniques are commonly used for each model individually, there is currently no concurrent parallelization strategy for both. This study proposed an open-source, Parallelized, and modular modeling software for regional Hydrologic processes and Landslides simulation and prediction (PHyL v1.0). It offers parallel computation in both hydrological and 3D slope stability modules, cross-scale modeling ability via a soil moisture downscaling method, and advanced input/output (I/O) and post-processing visualization. Additionally, PHyL v1.0 is flexible and extensible, making it compatible with all mainstream operating systems. We applied PHyL v1.0 in the Yuehe River Basin, where the computational efficiencies, parallel performance, parameter sensitivity analysis, and predictive capabilities were evaluated. The PHyL v1.0 is therefore appropriately used as an advanced software for high-resolution and complex simulations of regional floods and landslides.","3D slope stability model; Flood-landslide events; Hydrological-geotechnical models; Parallel computation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-08","","","Water Resources","","",""
"uuid:224f5147-c85e-44b1-96c2-ccb747521c33","http://resolver.tudelft.nl/uuid:224f5147-c85e-44b1-96c2-ccb747521c33","Impact of Reduced Fluvial Sediment Supply on Saltwater Intrusion in the Yangtze Estuary","Zhu, C. (TU Delft Coastal Engineering; East China Normal University); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Deltares; East China Normal University); Guo, Leicheng (East China Normal University); He, Qing (East China Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2023","A decline of the fluvial sediment supply leads to coastal erosion and land loss. However, the fluvial sediment load may influence not only coastal morphodynamics but also estuarine hydrodynamics and associated saltwater intrusion. Previous studies revealed that suspended sediments influence estuarine hydrodynamics through various flow–sediment interactions. In this contribution, we systematically investigate how changes in fluvial sediment load and other climate-change-induced environmental change influence estuarine hydrodynamics and sediment dynamics. For this purpose, we utilize a well-calibrated fully coupled model in which hydrodynamics, saltwater intrusion, and sediment transport interact with each other, to explore saltwater intrusion in the Yangtze Estuary in response to a decline in the sediment load, modified discharge, and sea-level rise. Model results suggest that a 70% decline in the suspended sediment load weakens the impact of sediments on salinity-induced stratification and thereby reducing saltwater intrusion. Sea-level rise or discharge peak reduction increases saltwater intrusion. However, a fully coupled model accounting for sediment effects predicts a much larger increase in saltwater intrusion compared to noncoupled models. Whether this effect is important depends on estuarine sediment concentrations and therefore the potential role of sediments should be carefully investigated before applying a noncoupled model. This work highlights not only the relevance of a suspended sediment decline but also the use of fully coupled models for predicting saltwater intrusion in turbid estuaries and has broad implications for freshwater resource management in turbid estuarine systems influenced by human interventions and climate change.","fully coupled model; saltwater intrusion; sea-level rise; sediment dynamics; sediment supply; Yangtze Estuary","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:3c588d63-8900-4375-b60e-204cbe5cafd2","http://resolver.tudelft.nl/uuid:3c588d63-8900-4375-b60e-204cbe5cafd2","Tunable Crossed Andreev Reflection and Elastic Cotunneling in Hybrid Nanowires","Bordin, A. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech); Wang, Guanzhong (TU Delft QRD/Wimmer Group; Kavli Institute for Theoretical Sciences; QuTech); Liu, Chun Xiao (Kavli institute of nanoscience Delft; QuTech); ten Haaf, S.L.D. (TU Delft QRD/Goswami Lab; Kavli institute of nanoscience Delft; QuTech); van Loo, N. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech); Mazur, G.P. (TU Delft QRD/Wimmer Group; Kavli institute of nanoscience Delft; QuTech); Xu, D. (TU Delft BUS/Quantum Delft; Kavli institute of nanoscience Delft; QuTech); van Driel, D. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech); Zatelli, F. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech); Gazibegovic, Sasa (Eindhoven University of Technology); Badawy, Ghada (Eindhoven University of Technology); Bakkers, Erik P.A.M. (Eindhoven University of Technology); Wimmer, M.T. (TU Delft QN/Wimmer Group; Kavli institute of nanoscience Delft; QuTech); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech); Dvir, T. (TU Delft Qubit Research Division; TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech)","","2023","A short superconducting segment can couple attached quantum dots via elastic cotunneling (ECT) and crossed Andreev reflection (CAR). Such coupled quantum dots can host Majorana bound states provided that the ratio between CAR and ECT can be controlled. Metallic superconductors have so far been shown to mediate such tunneling phenomena, albeit with limited tunability. Here, we show that Andreev bound states formed in semiconductor-superconductor heterostructures can mediate CAR and ECT over mesoscopic length scales. Andreev bound states possess both an electron and a hole component, giving rise to an intricate interference phenomenon that allows us to tune the ratio between CAR and ECT deterministically. We further show that the combination of intrinsic spin-orbit coupling in InSb nanowires and an applied magnetic field provides another efficient knob to tune the ratio between ECT and CAR and optimize the amount of coupling between neighboring quantum dots.","","en","journal article","","","","","","","","","","Qubit Research Division","QRD/Kouwenhoven Lab","","",""
"uuid:5c9a3be7-548a-4c75-aa3e-7390d8148961","http://resolver.tudelft.nl/uuid:5c9a3be7-548a-4c75-aa3e-7390d8148961","Spin-filtered measurements of Andreev bound states in semiconductor-superconductor nanowire devices","van Driel, D. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech); Wang, Guanzhong (TU Delft QRD/Wimmer Group; Kavli institute of nanoscience Delft; QuTech); Bordin, A. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech); van Loo, N. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech); Zatelli, F. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech); Mazur, G.P. (TU Delft QRD/Wimmer Group; Kavli institute of nanoscience Delft; QuTech); Xu, D. (TU Delft BUS/Quantum Delft; Kavli institute of nanoscience Delft; QuTech); Gazibegovic, Sasa (Eindhoven University of Technology); Badawy, Ghada (Eindhoven University of Technology); Bakkers, Erik P.A.M. (Eindhoven University of Technology); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech); Dvir, T. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech)","","2023","Semiconductor nanowires coupled to superconductors can host Andreev bound states with distinct spin and parity, including a spin-zero state with an even number of electrons and a spin-1/2 state with odd-parity. Considering the difference in spin of the even and odd states, spin-filtered measurements can reveal the underlying ground state. To directly measure the spin of single-electron excitations, we probe an Andreev bound state using a spin-polarized quantum dot that acts as a bipolar spin filter, in combination with a non-polarized tunnel junction in a three-terminal circuit. We observe a spin-polarized excitation spectrum of the Andreev bound state, which can be fully spin-polarized, despite strong spin-orbit interaction in the InSb nanowires. Decoupling the hybrid from the normal lead causes a current blockade, by trapping the Andreev bound state in an excited state. Spin-polarized spectroscopy of hybrid nanowire devices, as demonstrated here, is proposed as an experimental tool to support the observation of topological superconductivity.","","en","journal article","","","","","","","","","","","QRD/Kouwenhoven Lab","","",""
"uuid:a5662ca4-853e-421e-bf12-41f7c9337fe8","http://resolver.tudelft.nl/uuid:a5662ca4-853e-421e-bf12-41f7c9337fe8","Eavesdropping Mobile App Activity via Radio-Frequency Energy Harvesting","Ni, Tao (City University of Hong Kong); Lan, G. (TU Delft Embedded Systems); Wang, Jia (Shenzhen University); Zhao, Qingchuan (City University of Hong Kong); Xu, Weitao (City University of Hong Kong)","","2023","Radio-frequency (RF) energy harvesting is a promising technology for Internet-of-Things (IoT) devices to power sensors and prolong battery life. In this paper, we present a novel side-channel attack that leverages RF energy harvesting signals to eavesdrop mobile app activities. To demonstrate this novel attack, we propose AppListener, an automated attack framework that recognizes fine-grained mobile app activities from harvested RF energy. The RF energy is harvested from a custom-built RF energy harvester which generates voltage signals from ambient Wi-Fi transmissions, and app activities are recognized from a three-tier classification algorithm. We evaluate AppListener with four mobile devices running 40 common mobile apps (e.g., YouTube, Facebook, and WhatsApp) belonging to five categories (i.e., video, music, social media, communication, and game); each category contains five application-specific activities. Experiment results show that AppListener achieves over 99% accuracy in differentiating four different mobile devices, over 98% accuracy in classifying 40 different apps, and 86.7% accuracy in recognizing five sets of application-specific activities. Moreover, a comprehensive study is conducted to show AppListener is robust to a number of impact factors, such as distance, environment, and non-target connected devices. Practices of integrating AppListener into commercial IoT devices also demonstrate that it is easy to deploy. Finally, countermeasures are presented as the first step to defend against this novel attack.","","en","conference paper","USENIX Association","","","","","Funding Information: We sincerely thank our shepherd and anonymous reviewers for their constructive comments. This research was substantially supported by NFSC (Project 62101471) and was partially supported by the Shenzhen Research Institute, City University of Hong Kong, the Research Grants Council of the Hong Kong SAR, China (ECS Project CityU 21201420 and GRF Project CityU 11201422), CityU APRC grant 9610563, CityU SRG-Fd grant 7005853, Shenzhen Science and Technology Funding Fundamental Research Program (Project No. 2021Szvup126), NSF of Shandong Province (Project No. ZR2021LZH010), and a grant from Chow Sang Sang Group Research Fund sponsored by Chow Sang Sang Holdings International Limited (Project No. 9229062). Any opinions, findings, and conclusions in this paper are those of the authors and do not necessarily of supported organizations.","","","","","Embedded Systems","","",""
"uuid:7e34bc5c-fc0e-4001-8dfb-2fe93191d4e2","http://resolver.tudelft.nl/uuid:7e34bc5c-fc0e-4001-8dfb-2fe93191d4e2","Morphodynamic Modeling of Tidal Basins: The Role of Sand-Mud Interaction","Colina Alonso, A. (TU Delft Coastal Engineering; Deltares); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Deltares; East China Normal University); van Weerdenburg, R.J.A. (Deltares); Huismans, Y. (TU Delft Coastal Engineering; Deltares); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2023","The morphology of tide-dominated systems is progressively influenced by human activities and climate change. Quantitative approaches aiming at understanding or forecasting the effects of interventions and climate change are often aggregated, thereby simplifying or schematizing the investigated area. In this work, we advance on the knowledge of sediment transport processes shaping tidal systems and on methodologies translating schematized model output into physically realistic variables. In terms of improved physics, we systematically evaluate the influence of sand-mud interaction processes. Most tidal systems are shaped by a mixture of sand and mud. Morphological models typically compute transport of sand and mud independently, despite studies clearly demonstrating that their physical behavior is mutually dependent. We investigate the effects of two interaction mechanisms (erosion interaction and roughness interaction, applied with varying mud erodibility) with a schematized process-based morphodynamic model. We convert model output into metrics that describe the meso-scale configuration of the modeled systems, allowing a quantitative comparison of scenarios. Modeled patterns and intertidal flat shape, size and composition widely vary with mud erodibility settings, but equally depend on the evaluated sand-mud interaction mechanisms (with erosion interaction having a larger effect than roughness interaction). Sand-mud interaction thus needs to be accounted for from a physical point of view, but also to improve predictions of tidal basin evolution models, particularly the (bimodally distributed) sediment composition of intertidal flats.","Delft3D; modeling; morphodynamics; morphological evolution; sand-mud interaction; tidal basins","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:8406e806-40a6-4de0-8bef-6f39bd640f2a","http://resolver.tudelft.nl/uuid:8406e806-40a6-4de0-8bef-6f39bd640f2a","Short- and long-term temporal network prediction based on network memory","Zou, L. (TU Delft Multimedia Computing); Ceria, A. (TU Delft Multimedia Computing); Wang, H. (TU Delft Multimedia Computing)","","2023","Temporal networks are networks whose topology changes over time. Two nodes in a temporal network are connected at a discrete time step only if they have a contact/interaction at that time. The classic temporal network prediction problem aims to predict the temporal network one time step ahead based on the network observed in the past of a given duration. This problem has been addressed mostly via machine learning algorithms, at the expense of high computational costs and limited interpretation of the underlying mechanisms that form the networks. Hence, we propose to predict the connection of each node pair one step ahead based on the connections of this node pair itself and of node pairs that share a common node with this target node pair in the past. The concrete design of our two prediction models is based on the analysis of the memory property of real-world physical networks, i.e., to what extent two snapshots of a network at different times are similar in topology (or overlap). State-of-the-art prediction methods that allow interpretation are considered as baseline models. In seven real-world physical contact networks, our methods are shown to outperform the baselines in both prediction accuracy and computational complexity. They perform better in networks with stronger memory. Importantly, our models reveal how the connections of different types of node pairs in the past contribute to the connection estimation of a target node pair. Predicting temporal networks like physical contact networks in the long-term future beyond short-term i.e., one step ahead is crucial to forecast and mitigate the spread of epidemics and misinformation on the network. This long-term prediction problem has been seldom explored. Therefore, we propose basic methods that adapt each aforementioned prediction model to address classic short-term network prediction problem for long-term network prediction task. The prediction quality of all adapted models is evaluated via the accuracy in predicting each network snapshot and in reproducing key network properties. The prediction based on one of our models tends to have the highest accuracy and lowest computational complexity.","Network memory; Network-based prediction; Short- and long-term prediction; Temporal networks; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Multimedia Computing","","",""
"uuid:90f1dd5c-15b1-48f2-924e-bb7b86c422f8","http://resolver.tudelft.nl/uuid:90f1dd5c-15b1-48f2-924e-bb7b86c422f8","Continuous Fatty Acid Decarboxylation using an Immobilized Photodecarboxylase in a Membrane Reactor","Zhou, Jianle (South China University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis); He, Qi (South China University of Technology); Chen, Wen (South China University of Technology); Ma, Yunjian (South China University of Technology); Wang, Yonghua (South China University of Technology; GuangdongYoumei Institute of Intelligent Bio-manufacturing Co. Ltd., v)","","2023","The realm of photobiocatalytic alkane biofuel synthesis has burgeoned recently; however, the current dearth of well-established and scalable production methodologies in this domain remains conspicuous. In this investigation, we engineered a modified form of membrane-associated fatty acid photodecarboxylase sourced from Micractinium conductrix (McFAP). This endeavour resulted in creating an innovative assembled photoenzyme-membrane (protein load 5 mg cm−2), subsequently integrated into an illuminated flow apparatus to achieve uninterrupted generation of alkane biofuels. Through batch experiments, the photoenzyme-membrane exhibited its prowess in converting fatty acids spanning varying chain lengths (C6–C18). Following this, the membrane-flow mesoscale reactor attained a maximum space-time yield of 1.2 mmol L−1 h−1 (C8) and demonstrated commendable catalytic proficiency across eight consecutive cycles, culminating in a cumulative runtime of eight hours. These findings collectively underscored the photoenzyme-membrane's capability to facilitate the biotransformation of diverse fatty acids, furnishing valuable benchmarks for the conversion of biomass via photobiocatalysis.","alkane biofuel; continuous photocatalysis; decarboxylation; photoenzyme-membrane; self-assembly","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-15","","","BT/Biocatalysis","","",""
"uuid:9cc2485e-a0ee-4106-a4f1-0e9bccb2181d","http://resolver.tudelft.nl/uuid:9cc2485e-a0ee-4106-a4f1-0e9bccb2181d","High-dimensional analysis reveals an immune atlas and novel neutrophil clusters in the lungs of model animals with Actinobacillus pleuropneumoniae-induced pneumonia","Li, Na (Jilin University); Zhu, Junhui (Jilin University); Chen, Peiru (Jilin University); Bao, Chuntong (Jilin University); Wang, Jun (Jilin University); Abdelaal, T.R.M. (TU Delft Pattern Recognition and Bioinformatics; Leiden University Medical Center); Chen, Dexi (Capital Medical University); Zhu, Sibo (School of Life Sciences Fudan University); Wang, Wenjing (Capital Medical University)","","2023","Due to the increase in bacterial resistance, improving the anti-infectious immunity of the host is rapidly becoming a new strategy for the prevention and treatment of bacterial pneumonia. However, the specific lung immune responses and key immune cell subsets involved in bacterial infection are obscure. Actinobacillus pleuropneumoniae (APP) can cause porcine pleuropneumonia, a highly contagious respiratory disease that has caused severe economic losses in the swine industry. Here, using high-dimensional mass cytometry, the major immune cell repertoire in the lungs of mice with APP infection was profiled. Various phenotypically distinct neutrophil subsets and Ly-6C+ inflammatory monocytes/macrophages accumulated post-infection. Moreover, a linear differentiation trajectory from inactivated to activated to apoptotic neutrophils corresponded with the stages of uninfected, onset, and recovery of APP infection. CD14+ neutrophils, which mainly increased in number during the recovery stage of infection, were revealed to have a stronger ability to produce cytokines, especially IL-10 and IL-21, than their CD14- counterparts. Importantly, MHC-II+ neutrophils with antigen-presenting cell features were identified, and their numbers increased in the lung after APP infection. Similar results were further confirmed in the lungs of piglets infected with APP and Klebsiella pneumoniae infection by using a single-cell RNA-seq technique. Additionally, a correlation analysis between cluster composition and the infection process yielded a dynamic and temporally associated immune landscape where key immune clusters, including previously unrecognized ones, marked various stages of infection. Thus, these results reveal the characteristics of key neutrophil clusters and provide a detailed understanding of the immune response to bacterial pneumonia.","Actinobacillus pleuropneumoniae; bacterial pneumonia; immune response; mass cytometry; neutrophils; piglet; subset","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:114ec390-cf50-4d98-9c83-a2a14ac00f33","http://resolver.tudelft.nl/uuid:114ec390-cf50-4d98-9c83-a2a14ac00f33","Progressive failure mechanisms of geosynthetic-reinforced column-supported embankments over soft soil: Numerical analyses considering the cracks-induced softening","Wang, Heng (Fujian University of Technology; CSCEC Strait Construction and Development Co., Ltd.); Chen, Feng (Fujian University of Technology); Shiau, Jim (University of Southern Queensland); Dias, Daniel (Université Grenoble Alpes); Lai, F. (TU Delft Geo-engineering; Fuzhou University); Huang, Jianhua (Fujian University of Technology)","","2023","Cement-based columns in combination with geosynthetic reinforcement is a well-established soft ground improvement technique to enhance embankment stability. This paper aims to present a finite-element (FE) study based on a case history of a geosynthetic-reinforced column-supported (GRCS) embankment over soft soil. In this study, the columns are simulated with an advanced Concrete model to simulate the development of possible cracking and induced strain-softening. Numerical results are compared against published centrifuge tests, giving confidence to the established FE model with the Concrete model. New insights into the progressive failure mechanisms of GRCS embankments over soft soil are then discussed by examining the stress paths, internal forces, and cracks, as well as the plastic failure zones of columns. In addition, the role of columns and geosynthetics on the progressive failure mechanisms (failure loads and sequences) is also examined by an extensive parametric study. The results suggest that provided the optimization of compressive and tensile forces in the columns combined with the tensile stiffness of the geosynthetics is put in place, more columns can be mobilized to resist global sliding failure and to improve the bearing capacity of GRCS embankments.","Crack; Finite element analysis; Geosynthetic-reinforced column-supported embankment; Progressive failure mechanism; Strain-softening","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-30","","","Geo-engineering","","",""
"uuid:aca57973-db89-4132-abcd-ca26bfa422ef","http://resolver.tudelft.nl/uuid:aca57973-db89-4132-abcd-ca26bfa422ef","A Self-Bias-Flip with Charge Recycle Interface Circuit with No External Energy Reservoir for Piezoelectric Energy Harvesting Array","Li, Zhen (Fudan University); Chen, Zhiyuan (Fudan University); Wang, Jing (Fudan University); Wang, Jiawei (Fudan University); Jiang, Junmin (Southern University of Science and Technology); Du, S. (TU Delft Electronic Instrumentation); Cheng, Xu (Fudan University); Zeng, Xiaoyang (Fudan University); Han, Jun (Fudan University)","","2023","This article presents a piezoelectric energy harvesting (PEH) interface circuit using a new self-bias-flip with the charge recycle (SBFR) technique without employing any additional energy reservoir. Traditional designs, including synchronous-switch harvesting on inductor (SSHI), synchronous-switch harvesting on capacitor (SSHC), synchronous electric charge extraction (SECE), etc., require additional capacitors or inductors to reverse the voltage on the PEH at the zero-crossing point. This design innovatively uses the inherent capacitors of the piezoelectric harvesters as the flipping capacitors. In order to improve the extract efficiency of the interface, the zero-crossing state is split into a charge recycle stage and a voltage-flip stage. For a piezoelectric array with 2^n PEHs, a configuration with (n-1) phases in the charge recycle stage is adopted to reduce the loss caused by direct charge neutralization. The charge redistribution loss is reduced by employing (2n+1) phases in the voltage-flip stage. The proposed principle has been implemented with discrete components and is verified by three different prototypes. The measurement results show that a flipping efficiency of 67% is achieved by utilizing SBFR with four PEHs. And the proposed interface can provide up to 5.2x improvement when compared with the full-bridge rectifier (FBR).","Energy harvesting; maximum output power improving rate (MOPIR); multiple input; piezoelectric energy harvester (PEH); self-bias-flip; synchronous-switch harvesting on inductor (SSHI)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-15","","","Electronic Instrumentation","","",""
"uuid:c069f7c5-5bb8-47c1-8f08-cd3c07497110","http://resolver.tudelft.nl/uuid:c069f7c5-5bb8-47c1-8f08-cd3c07497110","Self-Assembled Lenalidomide/AIE Prodrug Nanobomb for Tumor Imaging and Cancer Therapy","Mai, Zhijian (South China Normal University); Cao, Nengjie (South China Normal University); Cheng, Erzhuo (The First Affiliated Hospital of Guangzhou Medical University); Zeng, Zhiwen (South China Normal University); Feng, Yancong (South China Normal University); Wang, Yao (South China Normal University); French, P.J. (TU Delft Bio-Electronics); Lee, Yi Kuen (The Hong Kong University of Science and Technology); Yang, Haihong (The First Affiliated Hospital of Guangzhou Medical University)","","2023","To develop multifunctional small-molecule prodrugs is highly desirable for cancer treatment but remains challenging in intrinsic traceability. As an acid-cleavable linkage, a Schiff bases benefiting from its distinctive fluorescence quenching ability was selected to prepare a small-molecule prodrug with cancer-targeted and self-indicating. In this study, we designed and developed a multifunctional self-assembled nanobomb of amphiphilic TPE-Lenalidomide prodrug, which comprises a hydrophobic aggregation-induced emission (AIE) probe 4-(1,2,2-triphenylvinyl)benzaldehyde (TPE-CHO) and a hydrophilic anticancer drug Lenalidomide via a Schiff base linkage. We investigated the synergistic effect of d-PET and C═N isomerization which would keep the fluorescence of TPE-Lenalidomide in the “always off” state by density functional theory (DFT) calculation. Once reaching the pathological site, such a vesicular nanobomb of TPE-Lenalidomide will be acidolyzed to release the AIE probe and Lenalidomide molecules simultaneously, consequently realizing high-efficiency effects of tumor imaging and cancer therapy (cell viability: normal cell L929, ∼79.49%; cancer cell 4T1, ∼27.08%; p = 0.000118). This work may pave an avenue to prepare small-molecule prodrugs for tumor-targeted diagnosis and cancer therapy.","aggregation-induced emission; Schiff base linkage; self-assembly; small-molecule prodrug; tumor-targeted diagnosis and therapy","en","journal article","","","","","","","","2024-04-29","","","Bio-Electronics","","",""
"uuid:cc6471ea-5d59-45a4-90df-35b2274af624","http://resolver.tudelft.nl/uuid:cc6471ea-5d59-45a4-90df-35b2274af624","Surrogate models of heat transfer in fractured rock and their use in parameter estimation","Song, G. (TU Delft Applied Geology; China University of Petroleum - Beijing); Roubinet, Delphine (CNRS/Université de Montpellier II); Wang, Xiaoguang (Chengdu University of Technology); Li, Gensheng (China University of Petroleum - Beijing); Song, Xianzhi (China University of Petroleum - Beijing); Tartakovsky, Daniel M. (Stanford University)","","2023","Fracture distribution plays a significant role in the behavior of subsurface environments, affecting such activities as geothermal production, exploitation and management of groundwater resources, and long-term storage of nuclear waste and carbon dioxide. A key challenge in these and other applications is to estimate the fracture network properties from sparse and noisy observations. We evaluate the utility of cross-borehole thermal experiments for this task, using both physics-based particle-tracking (PBPT) heat-transfer approach and its deep neural network (DNN) surrogates. Synthetic data are provided by the PBPT simulations and used to train and test the DNN surrogates over a full range of the fracture network properties. We propose regionalized and step-by-step training techniques to reduce the computational cost of expensive PBPT forward solves over large ranges of the (to-be-estimated) parameters. Our numerical experiments suggest the feasibility of training a regionalized DNN surrogate over parameter ranges for which the PBPT solves are fast and extrapolating its predictions to parameter ranges with few additional data. We analyze the balance between computational cost and model accuracy, and provide both PBPT and DNN models for applications to others kinds of data.","DFN parameter inversion; Fractured rocks; Heat transfer; Particle tracking; Surrogate model","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-14","","","Applied Geology","","",""
"uuid:f95ac433-3b57-420c-aae7-24bdeef36fc3","http://resolver.tudelft.nl/uuid:f95ac433-3b57-420c-aae7-24bdeef36fc3","Innovative Electricity Market Designs to Support a Transition to (Near) 100% Renewable Power System: First Results from H2020 TradeRES Project","Estanqueiro, Ana (Laboratório Nacional de Energia e Geologia); Strbac, Goran (Imperial College London); Chrysanthopoulos, Nikolaos (Imperial College London); Santos, Gabriel (Polytechnic of Porto); Johanndeiter, Silke (EnBW AG); Algarvio, Hugo (Laboratório Nacional de Energia e Geologia); Syse, Helleik (Bityoga); Sperber, Evelyn (Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Wang, Ni (TNO); Sanchez Jimenez, I.J. (TU Delft Energie and Industrie); Qiu, Dawei (Imperial College London); Vale, Zita (Polytechnic of Porto); Nienhaus, Kristina (Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Kochems, Johannes (Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Schimeczek, Christoph (Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Sijm, Jos (DIANA FEA); De Vries, Laurens (TU Delft Energie and Industrie); Lopes, Fernando (Laboratório Nacional de Energia e Geologia); Couto, António (Laboratório Nacional de Energia e Geologia)","","2023","Developing innovative electricity market designs to facilitate a sustainable transition to (near) 100% renewable power systems while meeting societal needs is a crucial and actual topic of research. This article presents preliminary key findings from the H2020 European project TradeRES, addressing this critical topic. The project uses agent-based and optimization models to effectively capture the behaviour of different market players, and to analyse the current and future power system energy mixes of selected European case studies with different physical and spatial scales from: i) local energy communities and local energy markets (LEMs); ii) national/regional - the Netherlands, Germany, and Iberia (Portugal and Spain); and iii) pan-European energy markets. The first results on LEMs indicate a substantial economic benefit for participants and enhanced revenue streams for distributed energy resources, able to i) incentivise further decentralised investments; ii) promote the growth of variable renewable energy systems (vRES) and iii) increase flexibility at the local level. The outcomes are sensitive to the tariffs’ structure, while the retail sector competitiveness was identified as a critical parameter affecting its efficiency. For the pan-European and national/regional case studies, the first set of simulations had consistent outcomes, namely, by pointing out current design of energy-only markets to be insufficient to incentivize the high levels of vRES foreseen in Europe. Different support schemes (e.g., fixed market premia, contract for differences) were tested and results suggest they may play a relevant role in effectively covering the cost of vRES in a market environment.","electricity market; vres large scale integration; near 100% res power systems","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-19","","","Energie and Industrie","","",""
"uuid:80eeeea5-14ba-46c8-aea9-a9a6d0b6fec2","http://resolver.tudelft.nl/uuid:80eeeea5-14ba-46c8-aea9-a9a6d0b6fec2","How Emoji and Explanations Influence Adherence to AI Recommendations","Kernan Freire, S. (TU Delft Internet of Things); Jung, Ji Youn (Student TU Delft); Wang, C.W. (TU Delft Human-Centred Artificial Intelligence); Niforatos, E. (TU Delft Internet of Things); Bozzon, A. (TU Delft Sustainable Design Engineering)","","2023","Emoji have become an essential part of modern communication, helping to convey emotions and tone quickly and concisely. Emoji used by humans and Intelligent Agents (IA) have been shown to affect people’s decision making intentions, suggesting they could be used to manipulate users to follow their advice. We present a mixed-methods crowdsourcing study (N = 194) that shows that adherence to an IA’s recommendation and user experience are not affected by emoji when used in a positive, collaborative way. However, we demonstrate that explanations provided by an IA do increase adherence to its recommendation.","","en","conference paper","Association for Computing Machinery (ACM)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-22","","Sustainable Design Engineering","Internet of Things","","",""
"uuid:9539c468-9e56-4683-a1e2-6fa528298d70","http://resolver.tudelft.nl/uuid:9539c468-9e56-4683-a1e2-6fa528298d70","Electrostatic control of the proximity effect in the bulk of semiconductor-superconductor hybrids","van Loo, N. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Eindhoven University of Technology; Kavli institute of nanoscience Delft); Mazur, G.P. (TU Delft QRD/Wimmer Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Dvir, T. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, Guanzhong (TU Delft QRD/Wimmer Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Dekker, R.C. (TU Delft QN/Steele Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Lemang, M.F. (TU Delft QN/Afdelingsbureau; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Sfiligoj, C. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Bordin, A. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); van Driel, D. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; Kavli institute of nanoscience Delft)","","2023","The proximity effect in semiconductor-superconductor nanowires is expected to generate an induced gap in the semiconductor. The magnitude of this induced gap, together with the semiconductor properties like spin-orbit coupling and g-factor, depends on the coupling between the materials. It is predicted that this coupling can be adjusted through the use of electric fields. We study this phenomenon in InSb/Al/Pt hybrids using nonlocal spectroscopy. We show that these hybrids can be tuned such that the semiconductor and superconductor are strongly coupled. In this case, the induced gap is similar to the superconducting gap in the Al/Pt shell and closes only at high magnetic fields. In contrast, the coupling can be suppressed which leads to a strong reduction of the induced gap and critical magnetic field. At the crossover between the strong-coupling and weak-coupling regimes, we observe the closing and reopening of the induced gap in the bulk of a nanowire. Contrary to expectations, it is not accompanied by the formation of zero-bias peaks in the local conductance spectra. As a result, this cannot be attributed conclusively to the anticipated topological phase transition and we discuss possible alternative explanations.","","en","journal article","","","","","","","","","","","QRD/Kouwenhoven Lab","","",""
"uuid:9f9758ab-4f48-4451-a080-e330f462b891","http://resolver.tudelft.nl/uuid:9f9758ab-4f48-4451-a080-e330f462b891","Enhancing thermal degradation stability of BaSi2O2N2:Eu2+ for white light-emitting diodes by ultra-thin Al2O3 layer via atomic layer deposition","Zhao, Y. (TU Delft ChemE/Product and Process Engineering; Henan University of Science and Technology; Xiamen University); Wang, Xiao (Henan University of Science and Technology); Li, Quan an (Henan University of Science and Technology); Zhang, Xinyu (Xiamen University); Li, Ye (Xiamen University); Xie, Rong Jun (Xiamen University); van Ommen, J.R. (TU Delft ChemE/Product and Process Engineering); Hintzen, H.T.J.M. (TU Delft RST/Luminescence Materials)","","2023","The cyan-emitting BaSi2O2N2:Eu2+ phosphor is a promising narrow-band and high-efficiency luminescent material used in wide-color-gamut white light-emitting diodes (wLEDs). However, its serious degradation under thermal attacks hinders its practical applications and needs to be improved. Herein, we proposed to deposit a nano-sized Al2O3 film around each BaSi2O2N2:Eu2+ particle through atomic layer deposition (ALD) in a fluidized bed reactor to improve its thermal stability. Thermal gravimetric analysis results showed that the Al2O3 layer with a thickness of only 11 nm had an obvious anti-oxidization effect, by which the oxidation temperature in air of the Al2O3 coated phosphor was largely increased from ∼550 to ∼750 °C. Moreover, the Al2O3 coated phosphor remained 93% of its luminescence intensity in comparison to 73% of the uncoated one when degraded under water-steam at 200 °C for 24 h. The oxidization of both the BaSi2O2N2 host matrix and the doped Eu2+ ions was reduced by the Al2O3 layer. Meanwhile, the wLEDs fabricated with the Al2O3 coated phosphor showed a luminous flux of 3 times higher than that of the uncoated one when aged under 100 mA for 300 h. The greatly improved thermal degradation property of BaSi2O2N2:Eu2+ phosphor and the reliability of the wLEDs indicate that the ALD approach could be a feasible route to produce uniform and nano layers on phosphors and enhance their stability.","Atomic layer deposition; Phosphor; Thermal stability; wLED","en","journal article","","","","","","","","","","","ChemE/Product and Process Engineering","","",""
"uuid:cd05702e-a4ec-437b-981c-cd69042679a3","http://resolver.tudelft.nl/uuid:cd05702e-a4ec-437b-981c-cd69042679a3","Investigation on the effect of interface properties on compressive failure behavior of 3D woven composites through micromechanics-based multiscale damage model","Zheng, T. (TU Delft Structural Integrity & Composites; Harbin Institute of Technology); Guo, Licheng (Harbin Institute of Technology); Sun, Ruijian (Beijing Institute of Astronautical Systems Engineering, Beijing); Wang, Tongtong (Harbin Institute of Technology); Hong, Changqing (Harbin Institute of Technology); Benedictus, R. (TU Delft Structural Integrity & Composites); Pascoe, J.A. (TU Delft Structural Integrity & Composites)","","2023","In this paper, the effect of interface properties on the compressive failure behavior of 3D woven composites (3DWC) is investigated by incorporating a micromechanics-based multiscale damage model (MMDM). The correlation between the mesoscopic stress of yarns and microscopic stress of constituents is established by defining a stress amplification factor. With the microscopic stresses, the fiber breakage and matrix failure can be separately evaluated at the microscale, without assuming the yarns as transversely isotropic homogeneous materials. Especially, the interfacial debonding between yarns and matrix is also a dominant damage mode within 3DWC. Given that there is still a lack of studies on the influence of interfacial properties on the compressive failure behavior of 3DWC, it is meaningful to perform numerical parametric studies to reveal how the interface properties contribute to the damage mechanisms of 3DWC under compressions. The predicted results indicate that with the increase of interface strengths and fracture toughness, the compressive resistance of 3DWC can be significantly improved, resulting in higher strength and failure strain. Additionally, the studied 3DWCs with weak, medium and strong interfaces exhibit different damage development processes.","3D woven composites; Compressive failure behavior; Interface; Micromechanics-based multiscale damage model; Numerical parametric study","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-29","","","Structural Integrity & Composites","","",""
"uuid:e8093649-6344-4618-bed4-80d48845ac71","http://resolver.tudelft.nl/uuid:e8093649-6344-4618-bed4-80d48845ac71","Probing resonating valence bonds on a programmable germanium quantum simulator","Wang, C.A. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft); Déprez, C.C. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft); Tidjani, H. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft); Lawrie, W.I.L. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft); Hendrickx, N.W. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft); Sammak, A. (TU Delft BUS/TNO STAFF); Scappucci, G. (TU Delft QCD/Scappucci Lab; Kavli institute of nanoscience Delft); Veldhorst, M. (TU Delft QN/Veldhorst Lab; Kavli institute of nanoscience Delft)","","2023","Simulations using highly tunable quantum systems may enable investigations of condensed matter systems beyond the capabilities of classical computers. Quantum dots and donors in semiconductor technology define a natural approach to implement quantum simulation. Several material platforms have been used to study interacting charge states, while gallium arsenide has also been used to investigate spin evolution. However, decoherence remains a key challenge in simulating coherent quantum dynamics. Here, we introduce quantum simulation using hole spins in germanium quantum dots. We demonstrate extensive and coherent control enabling the tuning of multi-spin states in isolated, paired, and fully coupled quantum dots. We then focus on the simulation of resonating valence bonds and measure the evolution between singlet product states which remains coherent over many periods. Finally, we realize four-spin states with s-wave and d-wave symmetry. These results provide means to perform non-trivial and coherent simulations of correlated electron systems.","","en","journal article","","","","","","","","","","","QCD/Veldhorst Lab","","",""
"uuid:e4ed771f-b526-4f52-9082-4831fbeea3ce","http://resolver.tudelft.nl/uuid:e4ed771f-b526-4f52-9082-4831fbeea3ce","The dependence of light extraction improvement on optimized surface microstructure for AlGaN-based UVC-LEDs considering TM-polarized emission","Zhu, Yifan (University of Science and Technology Beijing); Lu, Huimin (University of Science and Technology Beijing); Wang, Jianping (University of Science and Technology Beijing); Yu, Tongjun (Peking University); Li, Z.Z.L. (TU Delft ImPhys/Esmaeil Zadeh group); Tian, Yucheng (Peking University)","","2023","In order to improve the light extraction of AlGaN-based short wavelength ultraviolet light emitting diodes (DUC-LEDs), a type of microstructure with high aspect ratio is introduced and optimized on the AlN substrate surface. And, particle swarm optimization (PSO) algorithm is used to inverse design of the surface microstructure to maximize the light extraction efficiency (LEE). Considering that the propagation characteristics of TM-polarized light are different from that of TE-polarized light, the optical field distribution and LEE is analyzed for the UVC-LEDs with different TE-polarized component when the optimized surface microstructure is applied. Furthermore, the preparation process tolerance of the high aspect ratio structure is discussed by calculating the LED's LEE when the structural deviation occurs or morphology changes. Simulation results show that, by using the optimized surface microstructure based on parabola cone array, the LEDs' LEE is increased from 4.4% to 8.7% and from 0.4% to 3.7% for TE-polarized and TM-polarized emission, respectively. In addition, it is demonstrated that the light extraction improvement by the surface microstructure has a good tolerance to the structural deviation and morphology. The results are significant for improving light extraction and realizing high efficient short wavelength AlGaN-based UVC-LEDs by designing surface microstructures.","Light extraction efficiency; Polarized component; Ultraviolet light emitting diodes","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-24","","","ImPhys/Esmaeil Zadeh group","","",""
"uuid:52379047-045d-44bc-aac7-75f871a62489","http://resolver.tudelft.nl/uuid:52379047-045d-44bc-aac7-75f871a62489","Design knowledge graph-aided conceptual product design approach based on joint entity and relation extraction","Huang, Y. (TU Delft Design Conceptualization and Communication; Northwestern Polytechnical University); Yu, Suihuai (Northwestern Polytechnical University); Chu, Jianjie (Northwestern Polytechnical University); Su, Zhaojing (Shandong University of Science and Technology); Zhu, Yaokang (East China Normal University); Wang, Hanyu (Northwestern Polytechnical University); Wang, Mengcheng (Northwestern Polytechnical University); Fan, Hao (Northwestern Polytechnical University)","","2023","Design knowledge is critical to creating ideas in the conceptual design stage of product development for innovation. Fragmentary design data, massive multidisciplinary knowledge call for the development of a novel knowledge acquisition approach for conceptual product design. This study proposes a Design Knowledge Graph-aided (DKG-aided) conceptual product design approach for knowledge acquisition and design process improvement. The DKG framework uses a deep-learning algorithm to discover design-related knowledge from massive fragmentary data and constructs a knowledge graph for conceptual product design. The joint entity and relation extraction model is proposed to automatically extract design knowledge from massive unstructured data. The feasibility and high accuracy of the proposed design knowledge extraction model were demonstrated with experimental comparisons and the validation of the DKG in the case study of conceptual product design inspired by massive real data of porcelain.","Conceptual product design; deep learning; design knowledge graph; joint entity and relation extraction; knowledge acquisition","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-12-09","","","Design Conceptualization and Communication","","",""
"uuid:ce8caae5-ca57-46ef-b749-38474a36cba4","http://resolver.tudelft.nl/uuid:ce8caae5-ca57-46ef-b749-38474a36cba4","Recent Advances in MercuryDPM","Thornton, Anthony R. (University of Twente; Mercury Lab BV); Plath, Timo (University of Twente); Ostanin, Igor (University of Twente); Götz, Holger (Friedrich-Alexander-Universität Erlangen-Nürnberg); Bisschop, Jan Willem (University of Twente; Mercury Lab BV); Hassan, Mohamed (University of Twente); Roeplal, R.N. (TU Delft Transport Engineering and Logistics); Wang, Xiuqi (University of Twente); Pourandi, Sahar (University of Twente); Weinhart, Thomas (University of Twente; Mercury Lab BV)","","2023","In this paper we introduce the open-source code MercuryDPM: a code for simulating discrete particles. The paper discusses software and management issues that may be interesting for the developers of other open-source codes. Then we review the new features that have been added since the last publication: an improved Hertz-Mindlin model; a new liquid bridge model of Lian and Seville; a droplet-spray model; better support for re-creating complex, measured particle size distributions; a new implementation of rigid clumps; an implementation of elastic membranes; a wear model for walls; a soft-kill feature and a cloud-deployment interface for AWS.","(Wet) Granular Materials; Cloud compung; DEM; DPM; MercuryDPM; open-source","en","journal article","","","","","","","","","","","Transport Engineering and Logistics","","",""
"uuid:cd3f0258-b2c3-4199-8911-e9cf89987a9f","http://resolver.tudelft.nl/uuid:cd3f0258-b2c3-4199-8911-e9cf89987a9f","Assessment of the impact of tidal power extraction from the Eastern Scheldt storm surge barrier through the evaluation of a pilot plant","de Fockert, Anton (Deltares); Bijlsma, Arnout C. (Deltares); O'Mahoney, Tom S.D. (Deltares); Verbruggen, Wilbert (Deltares); Scheijgrond, Peter C. (Bluespring); Wang, Zhengbing (TU Delft Coastal Engineering)","","2023","Hydraulic structures can be a promising place for tidal energy extraction due to the high flow velocities, easy access to the power grid and easy access for maintenance. However, quantification of the impacts of a tidal power plant in a hydraulic structure is not straight forward. In 2015 a pilot plant consisting of an array of five Tocardo tidal turbines was installed in the Eastern Scheldt Storm Surge Barrier in the Netherlands. This pilot was accompanied by monitoring studies to verify that the operation of the plant had no adverse impact on the barrier and its surroundings. This paper presents the assessment of the hydraulic impact of the tidal power plant in the storm surge barrier based on an analysis of water level and current measurements, combined with numerical modeling and followed by an assessment of the environmental impact with emphasis on the effects on the intertidal areas in the estuary. This validation approach by a pilot plant is imperative to understand the interaction between tidal turbines and the hydraulic structure on the local scale. This understanding gives extra credibility to the predictions of the extrapolated large-scale and large array assessments which will always be fully numerical.","Computation fluid dynamics modelling; Environmental impact; Field measurements; Hydraulic structure; Hydrodynamic modelling; Tidal energy","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:dc2b3fef-e786-4cd4-823c-42d94521f8e7","http://resolver.tudelft.nl/uuid:dc2b3fef-e786-4cd4-823c-42d94521f8e7","Influence of SBS on the Aging Properties of High-Content Terminal Blend Rubber Modified Asphalt","Wang, Sheng (Tongji University); Huang, Weidong (Tongji University); Liu, X. (TU Delft Pavement Engineering); Lin, P. (TU Delft Pavement Engineering)","","2023","The goal of this study was to investigate the effect of styrene-butadiene-styrene (SBS) polymer on the aging properties of high-content terminal blend rubber modified asphalt (HCTBMA). All asphalt was tested for chemo-rheological properties using an attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) test, temperature sweep test, frequency sweep tests, and multiple stress creep recovery (MSCR) test. According to ATR-FTIR observations, SBS can retard the oxidation effect of HCTBMA during short-term aging, but its inhibitory effect is reduced during long-term aging. Furthermore, aging aggravates the degree of desulfurization of crumb rubber in HCTBMA as the SBS content increases. Compared with HCTBMA, neat asphalt has a lower elasticity at high temperatures and a higher elasticity at low temperatures. The addition of SBS to HCTBMA improves the elasticity of the material. The elasticity of HCTBMA decreases and then increases after aging, and SBS can reduce the aging degree of HCTBMA after aging. Moreover, based on Pearson correlation analysis, the correlation between the desulfurization of rubber and the degradation of polybutadiene in HCTBMA during aging is high.","Aging properties; Chemo-rheological properties; High-content terminal blend rubber modified asphalt (HCTBMA); Oxidation effect; Pearson correlation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-12-01","","","Pavement Engineering","","",""
"uuid:56832504-0352-48b8-9af8-e52da77f137a","http://resolver.tudelft.nl/uuid:56832504-0352-48b8-9af8-e52da77f137a","Assessing facial weakness in myasthenia gravis with facial recognition software and deep learning","Ruiter, Annabel M. (Leiden University Medical Center); Wang, Z. (TU Delft Pattern Recognition and Bioinformatics); Yin, Zhao (Student TU Delft); Naber, Willemijn C. (Leiden University Medical Center); Simons, Jerrel (Leiden University Medical Center); Blom, Jurre T. (Jurreblom, Apeldoorn); van Gemert, J.C. (TU Delft Pattern Recognition and Bioinformatics); Verschuuren, Jan J.G.M. (Leiden University Medical Center); Tannemaat, M.R. (Leiden University Medical Center)","","2023","Objective: Myasthenia gravis (MG) is an autoimmune disease leading to fatigable muscle weakness. Extra-ocular and bulbar muscles are most commonly affected. We aimed to investigate whether facial weakness can be quantified automatically and used for diagnosis and disease monitoring. Methods: In this cross-sectional study, we analyzed video recordings of 70 MG patients and 69 healthy controls (HC) with two different methods. Facial weakness was first quantified with facial expression recognition software. Subsequently, a deep learning (DL) computer model was trained for the classification of diagnosis and disease severity using multiple cross-validations on videos of 50 patients and 50 controls. Results were validated using unseen videos of 20 MG patients and 19 HC. Results: Expression of anger (p = 0.026), fear (p = 0.003), and happiness (p < 0.001) was significantly decreased in MG compared to HC. Specific patterns of decreased facial movement were detectable in each emotion. Results of the DL model for diagnosis were as follows: area under the curve (AUC) of the receiver operator curve 0.75 (95% CI 0.65–0.85), sensitivity 0.76, specificity 0.76, and accuracy 76%. For disease severity: AUC 0.75 (95% CI 0.60–0.90), sensitivity 0.93, specificity 0.63, and accuracy 80%. Results of validation, diagnosis: AUC 0.82 (95% CI: 0.67–0.97), sensitivity 1.0, specificity 0.74, and accuracy 87%. For disease severity: AUC 0.88 (95% CI: 0.67–1.0), sensitivity 1.0, specificity 0.86, and accuracy 94%. Interpretation: Patterns of facial weakness can be detected with facial recognition software. Second, this study delivers a ‘proof of concept’ for a DL model that can distinguish MG from HC and classifies disease severity.","","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:748d1ee6-5b9b-41a8-adfc-588b0306995b","http://resolver.tudelft.nl/uuid:748d1ee6-5b9b-41a8-adfc-588b0306995b","A micro graphene high temperature sensor with a single Si3N4 protective layer","Tang, Chenggang (Beijing Jiaotong University); Zeng, Simei (Beijing Jiaotong University); Hong, H. (TU Delft Electronic Components, Technology and Materials); Fang, Yuan (Beijing Jiaotong University); Li, Yuning (Beijing Jiaotong University); Wang, Yuqiang (Beijing Jiaotong University); Zhu, Mingqiang (Beijing Jiaotong University); Sun, Jingye (Beijing Jiaotong University); Deng, Tao (Beijing Jiaotong University)","","2023","Temperature sensors are widely used in industrial production, national defense and military fields. The traditional temperature sensors normally operate in a limited temperature range no more than 200 °C, which cannot be used for extreme high temperature detections. In this paper, a thermal protection method for the sensing graphene membrane is proposed and a graphene high temperature sensor has been fabricated and investigated. By growing a single silicon nitride (Si3N4) protective layer on top of graphene, our design not only solves the problem that graphene is easily oxidized at high temperature, but also prevents graphene from being polluted by impurities, which would lead to the degradation of graphene performance. We further explore the protective effect of Si3N4 layer with different thicknesses on the performance of the sensor. It has been found that the 400 nm Si3N4 protective layer gives the best protective capability. The sensor exhibits a positive temperature coefficient (PTC) from 50 to 600 °C and a maximal temperature coefficient of resistance (TCR) value of 0.29% °C−1 at 150 °C is achieved. It has been demonstrated that our graphene high temperature sensor with protective layer structure maintains good stability not only at high temperature up to 600 °C, but also over a long-period of time under room temperature. In short, the high temperature sensor possesses a wide temperature measurement range with micro dimensions, a relatively high TCR and a smaller thermal hysteresis. The thermal protection approach proposed in this paper provides a new idea for the fabrication of high temperature pressure sensor, which is expected to be applied in aerospace engines and oil wells, etc.","Graphene high temperature sensor; Long-period stability; Temperature measurement; Thermal protection","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-12-18","","","Electronic Components, Technology and Materials","","",""
"uuid:4cf927d9-47c8-4f12-a118-2b7e51b24a2b","http://resolver.tudelft.nl/uuid:4cf927d9-47c8-4f12-a118-2b7e51b24a2b","Designed Multifunctional Spider Silk Enabled by Genetically Encoded Click Chemistry","Jiang, Bojing (The Hong Kong University of Science and Technology; Washington University in St. Louis); Tan, Sin Yen (The Hong Kong University of Science and Technology); Fang, Shiyu (The Hong Kong University of Science and Technology); Feng, Xiaohan (The Hong Kong University of Science and Technology); Park, B.P. (TU Delft ImPhys/Maresca group; The Hong Kong University of Science and Technology); Fok, Hong Kiu Francis (The Hong Kong University of Science and Technology); Yang, Zhongguang (The Hong Kong University of Science and Technology; SPES Tech Limited); Wang, Ri (The Hong Kong University of Science and Technology); Kou, Songzi (Greater Bay Biomedical InnoCenter); Wu, Angela Ruohao (The Hong Kong University of Science and Technology); Sun, Fei (The Hong Kong University of Science and Technology; Greater Bay Biomedical InnoCenter)","","2023","Spider silk is recognized for its exceptional mechanical properties and biocompatibility, making it a versatile platform for developing functional materials. In this study, a modular functionalization strategy for recombinant spider silk is presented using SpyTag/SpyCatcher chemistry, a prototype of genetically encoded click chemistry. The approach involves AlphaFold2-aided design of SpyTagged spider silk coupled with bacterial expression and biomimetic spinning, enabling the decoration of silk with various SpyCatcher-fusion motifs, such as fluorescent proteins, enzymes, and cell-binding ligands. The silk threads can be coated with a silica layer using silicatein, an enzyme for silicification, resulting in a hybrid inorganic–organic 1D material. The threads installed with RGD or laminin cell-binding ligands lead to enhanced endothelial cell attachment and proliferation. These findings demonstrate a straightforward yet powerful approach to 1D protein materials.","biomaterials; cell adhesion; click chemistry; silicification; spider silk","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-12-15","","","ImPhys/Maresca group","","",""
"uuid:ab9002c8-475b-43a9-9455-b92727e8f965","http://resolver.tudelft.nl/uuid:ab9002c8-475b-43a9-9455-b92727e8f965","Selective Peroxygenase-Catalysed Oxidation of Toluene Derivates to Benzaldehydes","Wang, Y. (TU Delft BT/Biocatalysis; Tianjin University); Teetz, Niklas (University of Applied Sciences Mittelhessen); Holtmann, Dirk (University of Applied Sciences Mittelhessen); Alcalde, Miguel (Institute of Catalysis, CSIC, Madrid); van Hengst, J.M.A. (TU Delft BT/Biocatalysis); Liu, Xiaoxiao (Chinese Academy of Sciences); Wang, Mengfan (Tianjin University); Qi, Wei (Tianjin University); Zhang, Wuyuan (Chinese Academy of Sciences); Hollmann, F. (TU Delft BT/Biocatalysis)","","2023","Biocatalytic oxidation reactions of toluene derivates to the corresponding aldehydes are typically challenged by regio- and chemoselectivity issues. In this contribution we address both challenges by a combined reactant- and reaction engineering approach. We demonstrate that the peroxygenase-catalysed transformation of ring-substituted toluenes proceeds highly regioselectively in benzylic position. Furthermore, neat reaction conditions not only enable attractive product concentrations (up to 185 mM) but also result in highly chemoselective oxidations to the aldehyde level.","Benzaldehydes; Biocatalytic oxidation; Peroxygenase; Selective oxyfunctionalisation; Solvent-free biocatalysis","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:5e66b4ac-c1b8-4408-9218-1ef58f22f537","http://resolver.tudelft.nl/uuid:5e66b4ac-c1b8-4408-9218-1ef58f22f537","Asymmetric Sites on the ZnZrOx Catalyst for Promoting Formate Formation and Transformation in CO2 Hydrogenation","Feng, Zhendong (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Tang, Chizhou (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Zhang, Pengfei (Chinese Academy of Sciences); Li, Kun (Chinese Academy of Sciences); Li, G. (TU Delft ChemE/Inorganic Systems Engineering); Wang, Jijie (Chinese Academy of Sciences); Feng, Zhaochi (Chinese Academy of Sciences); Li, Can (Chinese Academy of Sciences; University of Chinese Academy of Sciences)","","2023","The role of formate species for CO2 hydrogenation is still under debate. Although formate has been frequently observed and commonly proposed as the possible intermediate, there is no definite evidence for the reaction of formate species for methanol production. Here, formate formation and conversion over the ZnZrOx solid solution catalyst are investigated by in situ/operando diffuse reflectance infrared Fourier transform spectroscopy-mass spectroscopy (DRIFTS-MS) coupled with density functional theory (DFT) calculations. Spectroscopic results show that bidentate carbonate formed from CO2 adsorption is hydrogenated to formate on Zn-O-Zr sites (asymmetric sites), where the Zn site is responsible for H2 activation and the Zr site is beneficial for the stabilization of reaction intermediates. The asymmetric Zn-O-Zr sites with adjacent and inequivalent features on the ZnZrOx catalyst promote not only formate formation but also its transformation. Both theoretical and experimental results demonstrate that the origin of the excellent performance of the ZnZrOx catalyst for methanol formation is associated with the H2 heterolytic cleavage promoted by the asymmetric Zn and Zr sites.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-12-01","","","ChemE/Inorganic Systems Engineering","","",""
"uuid:af4301b8-c203-41db-9b9c-04c1c4e85028","http://resolver.tudelft.nl/uuid:af4301b8-c203-41db-9b9c-04c1c4e85028","A novel unspecific peroxygenase from Agaricus bisporus var. bisporus for biocatalytic oxyfunctionalisation reactions","Li, Tiantian (South China University of Technology); Liang, Hongjing (South China University of Technology); Wu, Bin (South China University of Technology); Lan, Dongming (South China University of Technology); Ma, Yunjian (South China University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Yonghua (South China University of Technology)","","2023","Unspecific peroxygenases (UPOs) represent an emerging class of catalysts for the selective oxyfunctionalisation of C–H- and C = C groups. Until now, only a few UPOs have been characterised. In this study, we report a new peroxygenase identified from the Unspecific Peroxygenase Database. The UPO from Agaricus bisporus var. bisporus (AbvbUPO) has been heterologously expressed in Aspergillus niger and initially characterised with respect to its basic biochemical features. Furthermore, its catalytic properties were evaluated with enzymatic cascade reactions of choline oxidase (AnChOx) and AbvbUPO, which the AnChOx provided H2O2 necessary via reductive activation of oxygen in situ. Three types of oxyfunctionalizations, such as hydroxylation of ethylbenzene, epoxidations of styrene and cyclohexene, sulfoxidations of methyl phenyl sulfide and phenyl vinyl sulfide, were successfully achieved. We also investigated the activity of AbvbUPO on fatty acids in some more detail. The experimental results show that Under the above conditions, AbvbUPO had the higher activity for cyclohexene epoxidation and sulfonation of sulfide substrates. The concentration of epoxy cyclohexane was 2.91 mM, and the concentration of methyl phenyl sulfoxide was 3.69 mM. The regioselectivity of AbvbUPO was ω-1 bonds position of linear saturated fatty acid. All in all, AbvbUPO exhibits some interesting differences which may put the basis for further understanding of the factors determining peroxygenase selectivity.","Agaricus bisporus var. bisporus; Heme-thiolate peroxidase; Heterologous expression; Oxyfunctionalisation; Unspecific peroxygenase","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:bc824f66-ea8e-4f00-8b6c-b968b798c8ea","http://resolver.tudelft.nl/uuid:bc824f66-ea8e-4f00-8b6c-b968b798c8ea","Stretchable strain sensor based on HfSe2/LIG composite with high sensitivity and good linearity within a wide range","Yang, Huiru (Harbin Institute of Technology; Southern University of Science and Technology); Wang, S. (TU Delft Bio-Electronics); Huang, Qianming (Harbin Institute of Technology; Southern University of Science and Technology); Tan, C. (TU Delft Electronic Components, Technology and Materials); Gao, Chenshan (Southern University of Science and Technology); Xu, Siyuan (Southern University of Science and Technology); Ye, Huaiyu (Southern University of Science and Technology; Chongqing University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2023","Flexible strain sensors based on nanomaterials have sparked a lot of interest in the field of wearable smart electronics. Laser induced graphene (LIG) based sensors in particular stand out due to their straightforward fabrication procedure, three-dimensional porous structures, and exceptional electromechanical capabilities. Recent studies have focused on LIG composites, however, it is still difficult to achieve great sensitivity and excellent linearity in a wide linear working range. Herein, a strain sensor with high sensitivity and good linearity is prepared in this work, which was realized by carbonizing the polyimide film coated with HfSe2 to obtain three-dimensional porous graphene nanosheets decorated with HfSe2 (HfSe2/LIG). After being transferred to the flexible substrate of Ecoflex, it exhibits high stretchability, hydrophobicity and robustness, and obtains excellent electromechanical properties. The HfSe2/LIG strain sensor demonstrated high sensitivity (gauge factor, GF ≈ 46), a low detection limit (0.02%), good linearity (R2 = 0.99) in a large working range (up to 30%), and a quick response time (0.20 s). Additionally, it exhibits good stability and consistent behavior across a large number of strain/release test cycles (>3000 cycles). With these benefits, the sensor can be used to monitor various limb movements (including finger, wrist and neck movements) and minute artery activity, and can generate reliable signals. Therefore, the HfSe2/LIG-based sensor has enormous potential for use in wearable intelligent electronics and movement monitoring.","HfSe/LIG composite; Piezoresistive strain sensor; Wearable electronics","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-12-13","","","Bio-Electronics","","",""
"uuid:b26c67dd-7257-49aa-82df-d039ac6b8f2d","http://resolver.tudelft.nl/uuid:b26c67dd-7257-49aa-82df-d039ac6b8f2d","Efficient simulation of CO2 migration dynamics in deep saline aquifers using a multi-task deep learning technique with consistency","Zhao, M. (TU Delft Aerodynamics); Wang, Y. (China University of Geosciences, Wuhan); Gerritsma, M.I. (TU Delft Aerodynamics); Hajibeygi, H. (TU Delft Reservoir Engineering)","","2023","CO2 sequestration and storage in deep saline aquifers is a promising technology for mitigating the excessive concentration of the greenhouse gas in the atmosphere. However, accurately predicting the migration of CO2 plumes requires complex multi-physics-based numerical simulation approaches, which are prohibitively expensive due to highly nonlinear coupled governing equations and uncertainties in heterogeneous spatial parameter distributions. To address this challenge, we developed an end-to-end deep learning workflow employing encoder–decoder architectures with residual network (ResNet) to efficiently predicts the spatial–temporal evolution of the solution CO2-brine ratio (Rs) and gas saturation (Sg) – the two essential tasks for quantifying the amount of trapped CO2 – given heterogeneous permeability fields as input. Specifically, we introduce a general multi-task learning with consistency (MTLC) framework to simultaneously predict Rs and Sg. The MTLC model leverages related tasks with less computational expensive labeled datasets to improve generalization ability. In our study, predictions for multiple tasks from the same permeability realization are not independent but expected to be consistent, as the proposed framework utilizes data-driven cross-task consistency constraints to augment learning of related tasks. Our deep learning model is trained based on physical trapping mechanisms, which play a dominant role in the CO2 migration process. The results demonstrate that the MTLC model with joint learning yields more accurate predictions and improved generalization for predicting CO2 migration in several test cases. Furthermore, our workflow is 105 times faster than a high-fidelity physics-based numerical simulator, making it a viable alternative for field-scale applications.","Deep learning method; Geologic carbon storage; Multi-task learning; Multiphase flow in porous media","en","journal article","","","","","","","","","","","Aerodynamics","","",""
"uuid:be666916-eb5f-422c-b28c-18fef9f155b9","http://resolver.tudelft.nl/uuid:be666916-eb5f-422c-b28c-18fef9f155b9","Rank classification method for cascade reservoirs considering scale, benefits, and risk consequences","Wang, Te (Zhengzhou University); Li, Zongkun (Zhengzhou University); Ge, W. (TU Delft Safety and Security Science; Zhengzhou University; Yellow River Engineering Consulting Co); Zhang, Yadong (Zhengzhou University); Jiao, Yutie (Zhengzhou University); Jing, Laihong (Yellow River Engineering Consulting Co); van Gelder, P.H.A.J.M. (TU Delft Safety and Security Science)","","2023","Cascade reservoirs are essential in water resource utilization, flood control, and disaster mitigation. They have been built in several rivers worldwide. The rank classification for cascade reservoirs has significant practical implications for resource distribution decisions and risk management strategies and is also essential for ensuring the security of the basin. Internationally, reservoirs are typically classified based on project scale and dam failure consequences, whereas the risk transmission and superposition effect renders the classification method of reservoirs not directly applicable to cascade reservoirs. Therefore, to address this issue, this study proposed a rank classification method for cascade reservoirs. First, based on the scale, benefits, and risk consequences of dam failure, an index system for the rank classification of cascade reservoirs was established. Second, by constructing social risk criteria for cascade reservoirs and establishing a link among “project rank-reliability index-annual failure probability,” the allowable dam failure losses for different project ranks were determined. Thereafter, considering risk transmission and superposition, the rank classification standard and index quantification method for cascade reservoirs were proposed. Finally, five cascade reservoirs were selected for a feasibility study. The proposed method provides a supplement to the current rank classification standard of water conservancy projects in China and can also serve as a reference for risk assessment and classification management of cascade reservoirs in other countries.","Cascade reservoirs; Dam failure; Flood inundation; Risk management; Risk transmission","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-12-24","","","Safety and Security Science","","",""
"uuid:dc2918a4-fbf8-4723-bacb-e3a984ffcbd7","http://resolver.tudelft.nl/uuid:dc2918a4-fbf8-4723-bacb-e3a984ffcbd7","面 向 城 市 场 景 异 源 多 时 相 点 云 的 自 动 配 准","Yang, Z. (TU Delft Urban Data Science; Tongji University); Ye, Qin (Tongji University); Wang, Xufei (Tongji University); Peters, R.Y. (TU Delft Urban Data Science)","","2023","Objective Recent advancements in laser scanners and photogrammetry technology have significantly reduced the cost of acquiring 3D point clouds. Consequently, various types of point clouds have gradually become popular data sources for urban applications. The accurate registration of cross-source and multi-temporal point clouds must be ensured before developing applications based on 3D point clouds. However, this is a challenging task owing to (1) the large amount of data to be considered, (2) the wide discrepancy in characteristics between cross-source point clouds, and (3) the significant changes in a scene represented by multi-temporal point clouds. These data characteristics can harm the extraction and matching of registration primitives, resulting in the poor performance of marker-free registration techniques. In this paper, we propose an automated, efficient, and marker-free method for registering cross-source and multi-temporal point clouds in urban areas. Methods The proposed registration method comprises three stages: keypoint generation, correspondence matching, and transformation estimation. (1) Keypoint generation. We generate object-level virtual keypoints as registration primitives rather than directly extracting local features from point clouds, which are redundant and sensitive to outliers and missing data. Specifically, the ground points are first filtered out via the cloth simulation filtering algorithm. The remaining points are decomposed into planar segments by fitting planes in a region-growing manner. Finally, virtual keypoints are determined as the endpoints of intersecting line segments of two adjacent planes. (2) Correspondence matching. First, local triangles are constructed using the generated virtual keypoints as vertices to encode the relative spatial relationships among keypoints within a point cloud. Second, the triangle sets of both point clouds are mapped to a feature space where the triangles become 3D feature points. For each feature point in the source point cloud, we determine its closest point in the target point cloud, forming triangle pairs between the two point clouds. Finally, we propose an improved global matching approach with linear time complexity to extract correspondences encoded in the triangle pairs. (3) Transformation estimation. As cross-source and multi-temporal point clouds are typically well-leveled, registration can be achieved by aligning the two point clouds horizontally and translating them vertically. We use the horizontal coordinates of the correspondences to estimate the 2D horizontal transformation and their vertical coordinates to calculate the vertical translation. Results and Discussions We evaluated the effectiveness of the proposed method using large-scale real-world urban point clouds. The experimental data consist of six cross-source and multi-temporal point clouds, including three airborne light detection and ranging (LiDAR) point clouds and three photogrammetric point clouds, which cover an urban area of 1. 8 km2 in Rotterdam, the Netherlands. Each point cloud comprises a large number of points (approximately 20‒60 million points per point cloud; refer to Table 1 for details). Additionally, as the point clouds were collected over a long period of time, many of the objects in the scene have changed considerably. These two characteristics make them suitable for performing comprehensive evaluations of automatic marker-free registration methods. To evaluate the registration results qualitatively, we visualized a randomly selected region (Fig. 7) and three manually selected buildings with varying architectural styles (Fig. 8). Despite the different characteristics of cross-source point clouds and the significant changes in scenes, the proposed method could accurately align all five registration pairs formed by the six experimental point clouds. To evaluate the registration results quantitatively, we calculated both matrix-based errors (i. e., rotation and translation errors) as well as pointwise errors. The evaluation is summarized in Table 4. Our automatic registration results have an average pointwise error of 6.4 cm, whereas the average matrix-based errors are 0.2′for rotation and 7.4 cm for translation. Furthermore, despite the massive size of the experimental point clouds, the proposed approach required only 105.7 s to achieve pairwise registration on average. Both qualitative and quantitative results demonstrate the effectiveness of the proposed method for registering cross-source and multi-temporal urban point clouds. Conclusions A fully automated marker-free registration approach is presented for cross-source and multi-temporal point clouds in urban environments. Object-level virtual keypoints are generated from urban point clouds as registration primitives, thereby overcoming the challenge of identifying valid corresponding features. By encoding rigid body spatial relations among the generated virtual keypoints, we establish correspondences between the source and target point clouds, resulting in efficient matching for large-scale urban scenes. Experiments on real-world data demonstrate that the proposed method can automatically, accurately, and efficiently register cross-source and multi-temporal point clouds in urban areas, indicating its practical utility. In the future, we would like to collect more data to test the robustness of the proposed method. Moreover, we intend to study the potential of the proposed matching algorithm in the fusion of general multi-source data, e. g. , aligning 3D building point clouds with 2D building footprints.","cross-source and multitemporal point clouds; kinematics of rigid bodies; light detection and ranging; photogrammetric point clouds; point cloud registration; remote sensing","zh","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-14","","","Urban Data Science","","",""
"uuid:34f87dcb-fec8-4c80-aebd-429c8401958c","http://resolver.tudelft.nl/uuid:34f87dcb-fec8-4c80-aebd-429c8401958c","Direct discharge of sewage to natural water through illicitly connected urban stormwater systems: An overlooked source of dissolved organic matter","Zhang, Ruihua (Tongji University); Xiao, Rong (Tongji University); Wang, Feifei (Shanghai University); Chu, Wenhai (Tongji University; Shanghai Institute of Pollution Control and Ecological Security); Hu, Jinglong (Tongji University); Zhang, Yu (Tongji University); Jin, Wei (Tongji University; Shanghai Institute of Pollution Control and Ecological Security); van der Hoek, J.P. (TU Delft Sanitary Engineering); Xu, Zuxin (Tongji University; Shanghai Institute of Pollution Control and Ecological Security)","","2023","The illicit connection of sewage pipes to stormwater pipes commonly occurs in urban stormwater systems. This brings problems that sewage might be directly discharges into natural water and even drinking water sources without treatment, posing risks to ecological safety. Sewage contains various unknown dissolved organic matter (DOM), which could react with disinfectants and lead to the formation of carcinogenic disinfection byproducts (DBPs). Thus, understanding the impacts of illicit connections on downstream water quality is of significance. This study firstly investigated the characteristics of DOM using fluorescence spectroscopy and the formation of DBPs after chlorination in an urban stormwater drainage system in the case of illicit connections. The results found that the concentrations of dissolved organic carbon and dissolved organic nitrogen ranged from 2.6 to 14.9 mg/L and from 1.8 to 12.6 mg/L, respectively, with the highest levels occurring at the illicit connection points. Concerning DBP precursors, pipe illicit connections introduced considerable precursors of highly toxic haloacetaldehydes and haloacetonitriles into the stormwater pipes. Furthermore, illicit connections introduced more contents of tyrosine-like and tryptophan-like aromatic proteins, which may be related to foods, nutrients, personal care products, etc. in the untreated sewage. This indicated that the urban stormwater drainage system was a significant input source of DOM and DBP precursors to natural water. The results of this study are of great significance for protecting the security of water sources and promoting the sustainability of urban water environment.","Disinfection byproducts; Dissolved organic matter; Illicit connection; Precursors; Urban stormwater system","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-16","","","Sanitary Engineering","","",""
"uuid:8852ee21-5f8c-43be-b7d5-d29c2274fb69","http://resolver.tudelft.nl/uuid:8852ee21-5f8c-43be-b7d5-d29c2274fb69","Air entrainment and free-surface fluctuations in A-type hydraulic jumps with an abrupt drop","Luo, Maoyi (Sichuan University); Wang, Hang (Sichuan University); Zheng, Xiaohui (Sichuan University); Wüthrich, D. (TU Delft Hydraulic Structures and Flood Risk); Bai, Ruidi (Sichuan University); Liu, Shanjun (Sichuan University)","","2023","In high dam construction projects in China, stilling basin design with an abrupt bottom drop is sometimes introduced to reduce the bottom velocity and pressure loads by generating A-type hydraulic jumps. Although the stilling basin design is not new, A-type hydraulic jumps have not been studied taking into account the air entrainment and evolution of internal air–water flow structures. This paper presents an experimental study of self-aerated A-type jumps in terms of bubble transport and free-surface fluctuations over the bottom drop. Four Froude numbers from 4.1 to 10.3 are tested for three drop heights, in addition to the flat-bottom case. Compared to the classic hydraulic jumps, A-jumps are observed with longer jump lengths and weaker free-surface fluctuations. The downward deflection of the jet-shear flow and formation of a bottom roller in the step cavity require a modification to the analytical expression of velocity and void fraction distributions. The relationship between the bubble diffusivity and jump spreading rate differs from that in classic hydraulic jumps, suggesting a faster expansion of the bubble diffusion layer than the turbulent shear flow downstream of the drop, especially for large drop heights. At large approach velocities, the reattachment of the deflected jet-shear flow to the lowered bed may cause a local rise in bubble counts downstream the bottom roller. Further increase in drop height results in a W-jump with overwhelming bottom roller over the surface roller and an arced surface jet, which is beyond the scope of this study.","A-jump; abrupt drop; air entrainment; bottom roller; negative step","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-03-19","","","Hydraulic Structures and Flood Risk","","",""
"uuid:0f88f3d8-20d9-4c53-8f16-dbe0df9e9c64","http://resolver.tudelft.nl/uuid:0f88f3d8-20d9-4c53-8f16-dbe0df9e9c64","Extrinsic self-healing asphalt materials: A mini review","Wan, Pei (Wuhan University of Technology); Wu, Shaopeng (Wuhan University of Technology); Liu, Quantao (Wuhan University of Technology); Wang, Huan (Wuhan University of Technology); Gong, Xing (Wuhan University of Technology); Zhao, Zenggang (Wuhan University of Technology); Xu, S. (TU Delft Materials and Environment; Wuhan University of Technology); Jiang, Jian (Shenzhen Special Economic Zone Construction & Development Group Co. Ltd.); Fan, Lulu (Shenzhen Special Economic Zone Construction & Development Group Co. Ltd.); Tu, Liangliang (Shenzhen Special Economic Zone Construction & Development Group Co. Ltd.)","","2023","Self-healing is a biological phenomenon in which living organism responds to the suffered damage in a complex way. Inspired by the self-healing phenomenon in nature, various biomimetic healing methods rooted in intrinsic or extrinsic healing mechanisms have been explored. Research on novel self-healing asphalt materials with intelligent response is at the cutting-edge of materials science and offers a potential strategy for building long-life and low-carbon asphalt concrete infrastructure. This paper describes the progress of research on extrinsic self-healing asphalt materials and makes a clear distinction between intrinsic and extrinsic self-healing. The asphalt self-healing mechanism is interpreted by capillary flow theory, phase field theory, molecular diffusion theory and surface energy theory form various perspective. The extrinsic self-healing strategies including thermal induced healing and rejuvenator induced healing are proposed to enhance the healing level of cracked asphalt materials. A brief review of the methods including fracture-healing test and fatigue-healing test for assessing the efficacy of different extrinsic healing methods is presented. The thermal induced healing method bring high crack repair efficiency for asphalt concrete and the rejuvenator induced healing strategy not only improve the healing ratio of cracked asphalt concrete but also regenerate the ageing asphalt in situ. Important lessons for prospective research on the creation of novel self-healing asphalt materials are highlighted.","Asphalt materials; Extrinsic self-healing; Mechanisms; Sustainability","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-03-16","","","Materials and Environment","","",""
"uuid:e170c27e-c3d4-4a19-81b5-caed0cd780d1","http://resolver.tudelft.nl/uuid:e170c27e-c3d4-4a19-81b5-caed0cd780d1","Unveiling the inequalities in virtual water transfer in China: The environmental and economic perspectives","Wei, Ziyi (Beijing Forestry University); Huang, Kai (Beijing Forestry University); Chen, Ying (Beijing Forestry University); Wang, D. (TU Delft Sanitary Engineering); Yu, Yajuan (Beijing Institute of Technology); Xu, Ming (Tsinghua University); Kapelan, Z. (TU Delft Sanitary Engineering)","","2023","To alleviate the geographical mismatch between supply and demand of water resources, virtual water trade had attracted extensive attention. Many studies had estimated the virtual water flow and measured the virtual water inequality using Environmental Input-Output (EIO) model. However, EIO model ignores the feedback effect in the trade, which may lead an overestimation or underestimation of virtual water transfer. Moreover, while considering the relation between economic benefits and environmental costs, the studies of virtual water inequality are still limited in both number and methodology. Here, to address these gaps, we recalibrated the virtual water and value-added transfer in China's 30 provinces in 2017 using a new Environmental Spillover-Feedback Effects (ESFEs) model, and then measured the inequality between virtual water transfer and the resource endowments taking the value-added into account. Our results show that the virtual water transfer of half of provinces changed exceeding 50 %, with a maximum of 428 %. The ratio of net virtual water outflow to one-way virtual water inflow (which is called virtual water plunder index in this study) in Xinjiang is up to 935 %, which directly contributing to the inequality among regions. Moreover, the virtual water transfer in different regions is not compensated equally from the perspective of economy. As a result, some regions are getting both water resources and economic benefits, while others are getting the opposite. Our study highlights the importance of considering both the pressure on water resources and economic benefits when measuring the virtual water inequality. Our findings support policymakers in developing adequate responses, i.e., clarifying regional responsibilities of virtual water trade, building a whole industrial chain, and balancing the transfer of value-added and virtual water.","Inequality; Inter-regional transfer; Spillover-feedback effects; Virtual water trade","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-03-18","","","Sanitary Engineering","","",""
"uuid:e978f7eb-09db-4c1a-a897-48dacb1bf57d","http://resolver.tudelft.nl/uuid:e978f7eb-09db-4c1a-a897-48dacb1bf57d","Weakly-supervised Learning for Fine-grained Emotion Recognition using Physiological Signals","Zhang, T. (TU Delft Multimedia Computing; Centrum Wiskunde & Informatica (CWI)); El Ali, Abdallah (Centrum Wiskunde & Informatica (CWI)); Wang, Chen (Xinhua News Agency, Beijing); Hanjalic, A. (TU Delft Intelligent Systems); Cesar, Pablo (TU Delft Multimedia Computing; Centrum Wiskunde & Informatica (CWI))","","2023","Instead of predicting just one emotion for one activity (e.g., video watching), fine-grained emotion recognition enables more temporally precise recognition. Previous works on fine-grained emotion recognition require segment-by-segment, fine-grained emotion labels to train the recognition algorithm. However, experiments to collect these labels are costly and time-consuming compared with only collecting one emotion label after the user watched that stimulus (i.e., the post-stimuli emotion labels). To recognize emotions at a finer granularity level when trained with only post-stimuli labels, we propose an emotion recognition algorithm based on Deep Multiple Instance Learning (EDMIL) using physiological signals. EDMIL recognizes fine-grained valence and arousal (V-A) labels by identifying which instances represent the post-stimuli V-A annotated by users after watching the videos. Instead of fully-supervised training, the instances are weakly-supervised by the post-stimuli labels in the training stage. The V-A of instances are estimated by the instance gains, which indicate the probability of instances to predict the post-stimuli labels. We tested EDMIL on three different datasets, CASE, MERCA and CEAP-360VR, collected in three different environments: desktop, mobile and HMD-based Virtual Reality, respectively. Recognition results validated with the fine-grained V-A self-reports show that for subject-independent 3-class classification (high/neutral/low), EDMIL obtains promising recognition accuracies: 75.63% and 79.73% for V-A on CASE, 70.51% and 67.62% for V-A on MERCA and 65.04% and 67.05% for V-A on CEAP-360VR. Our ablation study shows that all components of EDMIL contribute to both the classification and regression tasks. Our experiments also show that (1) compared with fully-supervised learning, weakly-supervised learning can reduce the problem of overfitting caused by the temporal mismatch between fine-grained annotations and physiological signals, (2) instance segment lengths between 1-2 s result in the highest recognition accuracies and (3) EDMIL performs best if post-stimuli annotations consist of less than 30% or more than 60% of the entire video watching.","Annotations; deep multiple instance learning; Emotion recognition; emotion recognition; Feature extraction; physiological signals; Physiology; Solid modeling; Task analysis; temporal ambiguity; Training","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-05","","Intelligent Systems","Multimedia Computing","","",""
"uuid:1a997c5a-df01-48f8-b5ad-aea533d854ea","http://resolver.tudelft.nl/uuid:1a997c5a-df01-48f8-b5ad-aea533d854ea","Highly efficient carbon assimilation and nitrogen/phosphorus removal facilitated by photosynthetic O2 from algal-bacterial aerobic granular sludge under controlled DO/pH operation","Li, Zejiao (University of Tsukuba); Wang, Jixiang (University of Tsukuba); Liu, Jialin (University of Tsukuba); Chen, Xingyu (University of Tsukuba); Lei, Zhongfang (University of Tsukuba); Yuan, Tian (University of Tsukuba); Lee, Duu Jong (City University of Hong Kong; Yuan Ze University, Chung-Li); Lin, Y. (TU Delft Environmental Fluid Mechanics); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology)","","2023","Reducing CO2 emission and energy consumption is crucial for the sustainable management of wastewater treatment plants (WWTPs). In this study, an algal-bacterial aerobic granular sludge (AGS) system was developed for efficient carbon (C) assimilation and nitrogen (N)/phosphorus (P) removal without the need for mechanical aeration. The photosynthetic O2 production by phototrophic organisms maintained the dissolved oxygen (DO) level at 3-4 mg/L in the bulk liquid, and an LED light control system reduced 10–30% of light energy consumption. Results showed that the biomass assimilated 52% of input dissolved total carbon (DTC), and the produced O2 simultaneously facilitated aerobic nitrification and P uptake with the coexisting phototrophs serving as a C fixer and O2 supplier. This resulted in a stably high total N removal of 81 ± 7% and an N assimilation rate of 7.55 mg/(g-MLVSS∙d) with enhanced microbial assimilation and simultaneous nitrification/denitrification. Good P removal of 92–98% was maintained during the test period at a molar ∆P/∆C ratio of 0.36 ± 0.03 and high P release and uptake rates of 10.84 ± 0.41 and 7.18 ± 0.24 mg/(g- MLVSS∙h), respectively. Photosynthetic O2 was more advantageous for N and P removal than mechanical aeration. This proposed system can contribute to a better design and sustainable operation of WWTPs using algal-bacterial AGS.","Algal-bacterial aerobic granular sludge; Carbon fixation; Nitrogen assimilation; Photosynthetic oxygen; Simultaneous nitrogen and phosphorus removal","en","journal article","","","","","","","","2023-12-30","","","Environmental Fluid Mechanics","","",""
"uuid:e300954a-0bc8-4906-b715-f2b6901a7700","http://resolver.tudelft.nl/uuid:e300954a-0bc8-4906-b715-f2b6901a7700","Structure Design and Processing Strategies of MXene-Based Materials for Electromagnetic Interference Shielding","Oliveira, Filipa M. (University of Chemistry and Technology Prague); Azadmanjiri, Jalal (University of Chemistry and Technology Prague); Wang, Xuehang (TU Delft RST/Storage of Electrochemical Energy); Yu, Minghao (Technische Universität Dresden); Sofer, Zdeněk (University of Chemistry and Technology Prague)","","2023","The development of new materials for electromagnetic interference (EMI) shielding is an important area of research, as it allows for the creation of more effective and high-efficient shielding solutions. In this sense, MXenes, a class of 2D transition metal carbides and nitrides have exhibited promising performances as EMI shielding materials. Electric conductivity, low density, and flexibility are some of the properties given by MXene materials, which make them very attractive in the field. Different processing techniques have been employed to produce MXene-based materials with EMI shielding properties. This review summarizes processes and the role of key parameters like the content of fillers and thickness in the desired EMI shielding performance. It also discusses the determination of power coefficients in defining the EMI shielding mechanism and the concept of green shielding materials, as well as their influence on the real application of a produced material. The review concludes with a summary of current challenges and prospects in the production of MXene materials as EMI shields.","2D materials; electromagnetic interference shielding; green shielding materials; MXenes; power coefficients; processing strategies","en","review","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:4e39c6d0-f26b-402c-8be5-2993088c5bee","http://resolver.tudelft.nl/uuid:4e39c6d0-f26b-402c-8be5-2993088c5bee","A coupled MPM-DEM method for modelling soil-rock mixtures","Li, Jianguo (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Wang, Bin (Chinese Academy of Sciences); Wang, Di (Chinese Academy of Sciences); Zhang, Pei (Westlake University, Hangzhou); Vardon, P.J. (TU Delft Geo-engineering)","","2023","Aiming at modelling the mechanical behaviour of soil-rock mixtures accurately and efficiently, a coupled MPM-DEM formulation combining the material point method (MPM) and the discrete element method (DEM) is proposed. It is solved concurrently via the contact force linking the two individual methods. Specifically, the soil is modelled with MPM as continuums to avoid handling the contacts between fine particles. The rocks are modelled by DEM to capture the contact characteristics of rocks. This method is validated with ball impacting and block sliding tests first for the contact between material points and DEM particles. Its capability in describing the mechanics of soil-rock mixtures is thereafter proved by comparing the simulation results with pure DEM simulations of binary mixtures and laboratory tests of soil-rock mixtures. It is demonstrated that MPM-DEM can reproduce the stress–strain response of soil-rock mixtures and capture the influence of rock contents and rock sizes. In addition, a coarse-graining modelling scheme is implemented, i.e., representing the soil particles with fewer material points, which significantly increases the efficiency compared with pure DEM. Our proposed method provides a novel way to model soil-rock mixtures with reasonable computational efforts, which sheds light on simulating large-scale soil-rock mixtures in nature or engineering.","Binary granular mixture; Discrete element method; Material point method; Soil-rock mixture; Triaxial test","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-10","","","Geo-engineering","","",""
"uuid:f5e89339-8124-453b-9144-b891d7745780","http://resolver.tudelft.nl/uuid:f5e89339-8124-453b-9144-b891d7745780","Learning image representations for content-based image retrieval of radiotherapy treatment plans","Huang, Charles (Stanford University); Vasudevan, Varun (Stanford University); Pastor Serrano, O. (TU Delft RST/Medical Physics & Technology; Stanford University); Islam, Md Tauhidul (Stanford University); Nomura, Yusuke (Stanford University); Dubrowski, Piotr (Stanford University); Wang, Jen Yeu (Stanford University); Schulz, Joseph B. (Stanford University); Yang, Yong (Stanford University)","","2023","Objective. In this work, we propose a content-based image retrieval (CBIR) method for retrieving dose distributions of previously planned patients based on anatomical similarity. Retrieved dose distributions from this method can be incorporated into automated treatment planning workflows in order to streamline the iterative planning process. As CBIR has not yet been applied to treatment planning, our work seeks to understand which current machine learning models are most viable in this context. Approach. Our proposed CBIR method trains a representation model that produces latent space embeddings of a patient’s anatomical information. The latent space embeddings of new patients are then compared against those of previous patients in a database for image retrieval of dose distributions. All source code for this project is available on github. Main results. The retrieval performance of various CBIR methods is evaluated on a dataset consisting of both publicly available image sets and clinical image sets from our institution. This study compares various encoding methods, ranging from simple autoencoders to more recent Siamese networks like SimSiam, and the best performance was observed for the multitask Siamese network. Significance. Our current results demonstrate that excellent image retrieval performance can be obtained through slight changes to previously developed Siamese networks. We hope to integrate CBIR into automated planning workflow in future works.","content based image retrieval; deep learning; representation learning","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-03","","","RST/Medical Physics & Technology","","",""
"uuid:edb99a47-8d0c-4a38-a0a6-8d725503ae10","http://resolver.tudelft.nl/uuid:edb99a47-8d0c-4a38-a0a6-8d725503ae10","Engineering ketoreductases for the enantioselective synthesis of chiral alcohols","Qiao, Li (Hangzhou Normal University); Luo, Zhiyuan (Hangzhou Normal University); Chen, Haomin (Hangzhou Normal University); Zhang, Pengfei (Hangzhou Normal University); Wang, Anming (Hangzhou Normal University); Sheldon, R.A. (TU Delft BT/Biocatalysis; University of Witwatersrand)","","2023","The use of engineered ketoreductases (KREDS), both as whole microbial cells and isolated enzymes, in the highly enantiospecific reduction of prochiral ketones is reviewed. The homochiral alcohol products are key intermediates in, for example, pharmaceuticals synthesis. The application of sophisticated protein engineering and enzyme immobilisation techniques to increase industrial viability are discussed.","","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:75e42c32-4a70-4cc3-9497-7bceabd95855","http://resolver.tudelft.nl/uuid:75e42c32-4a70-4cc3-9497-7bceabd95855","Towards weathering and corrosion resistant, self-warning and self-healing epoxy coatings with tannic acid loaded nanocontainers","Wang, Jinke (University of Science and Technology Beijing); Tan, Weimin (Changzhou Paint and Coatings Industry Research Institute Limited Liability Company); Yang, Hao (University of Science and Technology Beijing); Rao, Xingxing (Changzhou Paint and Coatings Industry Research Institute Limited Liability Company); Luo, Xinliang (Changzhou Paint and Coatings Industry Research Institute Limited Liability Company); Ma, Lingwei (University of Science and Technology Beijing); Ren, Chenhao (University of Science and Technology Beijing); Mol, J.M.C. (TU Delft Team Arjan Mol); Zhang, Dawei (University of Science and Technology Beijing)","","2023","In this work, an active protective epoxy coating with weathering resistant, corrosion-warning, and self-healing properties was developed by incorporating tannic acid (TA) loaded mesoporous silica (MSN-TA) nanocontainers. The introduction of MSN-TA nanocontainers could alleviate the coating degradation via scavenging the radicals generated during UV irradiation. Compared with the blank coating, the coating containing 5 wt.% MSN-TA nanocontainers exhibited much less degradation in surface morphology, wettability and glossiness, and maintained a good barrier property after 384 h of accelerated weathering. Once the coating was damaged, the released TA could react with the Fe3+ ions to form a chelate that endowed the coating scratch with a visible black coloration, i.e. triggering a self-warning capability to indicate the initial onset of corrosion. In addition, the generated chelate could inhibit extensive corrosion propagation, offering a significant self-healing effect demonstrated by the stabilized impedance modulus values during 28 days of immersion in NaCl solution.","","en","journal article","","","","","","","","","","","Team Arjan Mol","","",""
"uuid:43e56678-b1b7-4c0b-86ab-f7bab139a717","http://resolver.tudelft.nl/uuid:43e56678-b1b7-4c0b-86ab-f7bab139a717","Effect of coordination number of particle contact force on rutting resistance of asphalt mixture","Niu, D. (Chang'an University); Shi, Weibo (Chang'an University); Wang, C. (TU Delft Pavement Engineering); Xie, Xiwang (Jiangsu Sobute New Materials Co. Ltd); Niu, Yanhui (Chang'an University)","","2023","Optimizing asphalt mix design at the indoor stage is of significant importance for enhancing the rutting resistance of asphalt mixture, which is affected by its structural characteristics. In this work, the coordination number of particle contact force (CNpcf) was proposed as an indicator to represent contact characteristics of skeleton structure aggregates in asphalt mixture. Nine asphalt mixtures with different gradations were designed, and the relationship of CNpcf with the number of aggregate contact zones (CZ) was established by combining rutting tests and digital image processing technique (DIP). The Mann-Whitney U test was implemented to analyze the distribution properties of inter-particle contacts before and after the rutting test. In addition, the resistance to the further expansion of rutting was analyzed. The results revealed a significant positive correlation (PCCs = 0.843, R2 = 0.711) between CNpcf and CZ. The content of coarse aggregates in the dominant structure did not exhibit monotonic related to anti-rutting performance of the asphalt mixture. Therefore, an optimum aggregate content of 57% was utilized. The Mann-Whitney U test revealed that the mesoscale skeleton structure of the asphalt mixes before and after rutting exhibited excellent stability. This study further indicated the applicability of combining CNpcf to adjust the mix design to enhance the rutting resistance of asphalt mixture and to prevent rutting expansion in flexible pavement.","Asphalt mixture; Digital image technology; Mann-Whitney U test; Road engineering; Rutting resistance; Skeleton structure","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-26","","","Pavement Engineering","","",""
"uuid:95616590-7096-4a00-b2b4-456623e3125e","http://resolver.tudelft.nl/uuid:95616590-7096-4a00-b2b4-456623e3125e","Prototyping Visible Light Communication for the Internet of Things Using OpenVLC","Guzman, Borja Genoves (IMDEA Networks Institute); Mir, Muhammad Sarmad (Carlos III University of Madrid); Fonseca, Dayrene Frometa (IMDEA Networks Institute; Carlos III University of Madrid); Galisteo, Ander (Dojo Five); Wang, Q. (TU Delft Embedded Systems); Giustiniano, Domenico (IMDEA Networks Institute)","","2023","Visible Light Communication (VLC) has emerged in the last few years as a promising technology not only for high-speed communication but also for serving a new generation of Internet of Things (IoT) devices that may leverage the pervasive lighting infrastructures. Integrating VLC in lighting environments for IoT requires the design of networked and intelligent luminaries and new IoT devices, encompassing the development of innovative technologies and new algorithms. A common experimental platform is necessary to lower the entrance barriers of VLC and speed up the research development. In this article, we provide guidelines for prototyping VLC for IoT applications, assisted by the open-source platform OpenVLC. We also introduce the new development on OpenVLC, which guarantees support for more powerful LEDs and much longer distance (extending the communication distance from 6 m to 19 m), dimming adaption, among other features. Its low-cost, open-source, and open-hardware designs allow researchers in the community to swiftly adapt it to suit their research purposes.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-18","","","Embedded Systems","","",""
"uuid:6773b204-263e-4cb8-9774-bc976423e731","http://resolver.tudelft.nl/uuid:6773b204-263e-4cb8-9774-bc976423e731","Exploring the Dynamic Impact of Extreme Climate Events on Vegetation Productivity under Climate Change","Xu, H. (TU Delft Hydraulic Structures and Flood Risk; East China Normal University); Tan, Jinkai (Sun Yat-sen University); Li, Chunlan (East China Normal University); Niu, Yiying (East China Normal University); Wang, Jun (East China Normal University)","","2023","As global warming continues to intensify, the relationship between diurnal temperature range (DTR) and vegetation productivity continues to change over time. However, the impact of DTR changes on vegetation activities remains uncertain. Thus, further study about how DTR changes affect the physiological activities of plants is also urgently needed. In this study, we employed copula function theory to analyze the impact of DTR on Normalized Difference Vegetation Index (NDVI) values during the spring, summer, and autumn seasons from 1982 to 2014 for various land types in the Inner Mongolia Plain (IMP), China. The results showed that the relationship between DTR and NDVI in the IMP was characterized by correlation at the upper tail and asymptotical independence at the lower tail. This demonstrated that the DTR had little effect on NDVI when they reached their minimum value. However, it has a significant impact on NDVI at its maximum values. This study provides valuable insight into the dynamic impact of monthly DTR on different land use types under climate change.","copula theory; diurnal temperature variation; extreme climate index; joint probability; normalized difference vegetation index","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:c1600edf-9d58-4302-9864-5702e568a44e","http://resolver.tudelft.nl/uuid:c1600edf-9d58-4302-9864-5702e568a44e","Chloride penetration resistance of engineered cementitious composite (ECC) subjected to sustained flexural loading","Wang, Chuan (Shandong Hi-Speed Group); Sun, Renjuan (Shandong University); Hu, Xinlei (Chongqing Luneng Development Group Co, Ltd.); Guan, Yanhua (Shandong University); Yang, Yingzi (Harbin Institute of Technology); Lu, Wei (Shandong University); Tian, Jun (Shandong Hi-Speed Group); Zhang, Hongzhi (Shandong University); Ge, Zhi (Shandong University); Šavija, B. (TU Delft Materials and Environment)","","2023","This paper presents a research on the chloride penetration behavior of engineered cementitious composites (ECC) under sustained flexural loads. Three load levels, i.e. 30 %, 60 % and 75 % of the ultimate flexural load were used. Chloride diffusion depth and concentration profile were measured 30, 60 and 150 days after the specimen was exposed to NaCl solution and compared with pre-loaded specimens. Influence of the sustained local bending stress and microcracks were investigated. It shows that under sustained loads, the relationship between the surface chloride content and maximum normal tensile stress can be described using an exponential equation. A binary model was developed to explain the correlation among the chloride ion diffusion coefficient, maximum normal tensile stress and exposure time. Changes of capillary pore structure and phase compositions were measured using mercury intrusion porosimeter and X-ray diffraction, respectively. Unlike mortar, the fiber bridging of ECC helps with limiting crack width and thus the diffusion process, and the measured results were used to explain the observed penetration behavior of ECC. It is believed that the current study provides theoretical foundation for the durable design of the ECC/concrete composite structure.","Chloride penetration behavior; Engineered cementitious composites; Maximum normal tensile stress; Microcracks; Sustained flexural load","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-26","","","Materials and Environment","","",""
"uuid:e99183f7-46f4-40a8-b2d0-7884c60afa6b","http://resolver.tudelft.nl/uuid:e99183f7-46f4-40a8-b2d0-7884c60afa6b","Existence and approximate solutions of a nonlinear model for the antarctic circumpolar current","Chu, Jifeng (Shanghai Normal University); Marynets, K. (TU Delft Delft Institute of Applied Mathematics; TU Delft Mathematical Physics); Wang, Z. (TU Delft Applied Mechanics; Shanghai Normal University)","","2023","We consider a nonlinear Neumann boundary value problem which is derived for the Antarctic Circumpolar Current. By the theory of topological degree, we prove the existence results for the problem with semilinear oceanic vorticity term. We also construct the approximate solutions for such a nonlinear model.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-02","","","Mathematical Physics","","",""
"uuid:c2eab784-af95-4bca-bac7-ccd275c62159","http://resolver.tudelft.nl/uuid:c2eab784-af95-4bca-bac7-ccd275c62159","Refined nonlinear fractional derivative model of vehicle-track coupling dynamics","Yang, Fan (Tongji University; Shanghai Jiao Tong University); Zhang, P. (TU Delft Railway Engineering); Wang, Yuan (Southern University of Science and Technology); Wei, Kai (Southwest Jiaotong University; Ministry of Education); Dong, Liwei (Tongji University); Wang, Ping (Southwest Jiaotong University; Ministry of Education)","","2023","The coupled vehicle-track system (CVTS) dynamics have been extensively investigated for decades. However, the calculation accuracy of prevailing vehicle-track coupling models needs to be improved in the high frequency range due to the inappropriate model simplification and neglect of material nonlinearity. In this study, we propose a refined numerical model of the CVTS that considers the nonlinear properties of the railpads and primary suspension using the fraction derivative Zener model. Furthermore, we more realistically simulate the wheelset, rail and railpad configuration with the elastic axle, solid finite element and surface-support models, respectively, and improve the computation efficiency by employing the mode superposition method. The results demonstrate that the refined CVTS model is more accurate than the classical model in simulating vehicle-track coupling dynamics above 2 kHz. In particular, there are significant differences in the dynamic response of the elastic wheelset model compared to the rigid model over a broad frequency range, with an 11% difference in the bogie acceleration response at the first dominant frequency. When the railpads are modeled using the surface-support model, the rail acceleration differences exceed 41% near 1 kHz and 44% near 2650 Hz, compared to the point-support model. Additionally, the rail response at various locations across the rail cross section can be calculated using the finite element method in this refined model. Overall. the proposed CVTS model provides high accuracy and efficiency for random vibration analysis, especially in the high frequency domain.","Elastic wheelset; Finite element method; High frequency; Nonlinear fractional derivative model; Vehicle-track coupled dynamics","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-17","","","Railway Engineering","","",""
"uuid:f63eedfa-b572-4ed8-ba67-baf1dfbb35b2","http://resolver.tudelft.nl/uuid:f63eedfa-b572-4ed8-ba67-baf1dfbb35b2","Assessment of Vigilance Level during Work: Fitting a Hidden Markov Model to Heart Rate Variability","Wang, Hanyu (Northwestern Polytechnical University); Chen, Dengkai (Northwestern Polytechnical University); Huang, Y. (TU Delft Design Conceptualization and Communication; Northwestern Polytechnical University); Zhang, Yahan (Shanghai Jiao Tong University); Qiao, Yidan (Northwestern Polytechnical University); Xiao, Jianghao (Northwestern Polytechnical University); Xie, Ning (Northwestern Polytechnical University); Fan, Hao (Zhejiang University)","","2023","This study aimed to enhance the real-time performance and accuracy of vigilance assessment by developing a hidden Markov model (HMM). Electrocardiogram (ECG) signals were collected and processed to remove noise and baseline drift. A group of 20 volunteers participated in the study. Their heart rate variability (HRV) was measured to train parameters of the modified hidden Markov model for a vigilance assessment. The data were collected to train the model using the Baum–Welch algorithm and to obtain the state transition probability matrix (Formula presented.) and the observation probability matrix (Formula presented.). Finally, the data of three volunteers with different transition patterns of mental state were selected randomly and the Viterbi algorithm was used to find the optimal state, which was compared with the actual state. The constructed vigilance assessment model had a high accuracy rate, and the accuracy rate of data prediction for these three volunteers exceeded 80%. Our approach can be used in wearable products to improve their vigilance level assessment functionality or in other fields that have key positions with high concentration requirements and monotonous repetitive work.","heart rate variability; hidden Markov model; psychomotor vigilance task; vigilance; visual search task; wearable device","en","journal article","","","","","","","","","","","Design Conceptualization and Communication","","",""
"uuid:d066db36-8155-4986-a95d-6c24c720972c","http://resolver.tudelft.nl/uuid:d066db36-8155-4986-a95d-6c24c720972c","Silicon heterojunction solar cells with up to 26.81% efficiency achieved by electrically optimized nanocrystalline-silicon hole contact layers","Lin, H. (TU Delft Cyber Security; Sun Yat-sen University; LONGi Green Energy Technology); Yang, Miao (LONGi Green Energy Technology); Ru, Xiaoning (LONGi Green Energy Technology); Wang, Genshun (Sun Yat-sen University; LONGi Green Energy Technology); Yin, Shi (LONGi Green Energy Technology); Peng, Fuguo (LONGi Green Energy Technology); Han, C. (TU Delft Photovoltaic Materials and Devices; Sun Yat-sen University); Procel Moya, P.A. (TU Delft Photovoltaic Materials and Devices); Isabella, O. (TU Delft Photovoltaic Materials and Devices)","","2023","Silicon heterojunction (SHJ) solar cells have reached high power conversion efficiency owing to their effective passivating contact structures. Improvements in the optoelectronic properties of these contacts can enable higher device efficiency, thus further consolidating the commercial potential of SHJ technology. Here we increase the efficiency of back junction SHJ solar cells with improved back contacts consisting of p-type doped nanocrystalline silicon and a transparent conductive oxide with a low sheet resistance. The electrical properties of the hole-selective contact are analysed and compared with a p-type doped amorphous silicon contact. We demonstrate improvement in the charge carrier transport and a low contact resistivity (<5 mΩ cm2). Eventually, we report a series of certified power conversion efficiencies of up to 26.81% and fill factors up to 86.59% on industry-grade silicon wafers (274 cm2, M6 size).","","en","journal article","","","","","","","","","","","Cyber Security","","",""
"uuid:f7b79a56-783a-44db-9756-44d927abca22","http://resolver.tudelft.nl/uuid:f7b79a56-783a-44db-9756-44d927abca22","Tacit Knowledge Elicitation for Shop-floor Workers with an Intelligent Assistant","Kernan Freire, S. (TU Delft Internet of Things); Wang, C.W. (TU Delft Human-Centred Artificial Intelligence); Ruiz Arenas, S. (Universidad EAFIT); Niforatos, E. (TU Delft Internet of Things)","","2023","Many industries face the challenge of capturing workers' knowledge to share it, particularly tacit knowledge. The operation of complex systems such as a manufacturing line is knowledge-intensive. Considering this knowledge's breadth and dynamic nature, existing knowledge-sharing solutions are inefficient and resource intensive. Conversational user interfaces are an efficient way to convey information that mimics how humans share knowledge; however, we know little about how to design them specifically for knowledge sharing, especially regarding tacit knowledge. In this work, we present an intelligent assistant that we have developed to support the elicitation of tacit knowledge from workers through systematic reflection. The system can interact with workers by voice or text and generate visualizations of shop floor data to support reflective prompts.","chatbots; human-centered AI; industry 5.0; intelligent assistant; knowledge sharing; systematic reflection; tacit knowledge","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","2023-10-19","","","Internet of Things","","",""
"uuid:5f35fdfd-cb84-4db1-8572-c6a25b8c9034","http://resolver.tudelft.nl/uuid:5f35fdfd-cb84-4db1-8572-c6a25b8c9034","Regeneration mechanisms of aged SBS modified asphalt from RAP materials: Molecule structure, morphology, phase transition, and interface adhesion characteristics","Dong, Fuqiang (Hohai University); Wang, Jincheng (Hohai University); Yu, Xin (Hohai University); Jiang, Mengmeng (Hohai University); Guo, Yongjia (Jiangsu Hi-speed New Material Technology Co., Ltd.); Wang, Shiyu (Hohai University); Zu, Yuanzhe (Hohai University); Ren, S. (TU Delft Pavement Engineering)","","2023","In this study, the environmentally friendly rejuvenators with waste thermal conductive oil, polymer, and the interfacial reinforcing agent were prepared. And the influence of the different rejuvenators on the rejuvenation mechanisms of aged SBS modified asphalt was characterized by different scales including the molecule structure, morphology, phase transition and interface adhesion characteristic, and macro performance. The results show that the thermal-oxidative aging process increases the molecular weight of asphalt, promotes the SBS phase to agglomerate, and decreases the high and low temperature performance, thermal stability, and adhesion. When the rejuvenator was added, the molecular weight distribution of asphalt binders can be improved, while adding the regenerant-II can supplement the SBS modifier and reform the cross-linking structure. Furthermore, the regenerant-II has a better recovery effect on the morphology structure and resumes the thermal behavior. And then softening point and ductility can be recovered by 89.7% and 94.8% of the original SBS modified asphalt. Under the action of the interfacial reinforcing agent, the regenerant-III could increase the adhesion work to 95.49% of the original SBS modified asphalt.","Aged SBS modified asphalt; Interface adhesion characteristics; Molecular structure; Morphology; Regenerant agent; Regeneration mechanisms","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care. Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-10","","","Pavement Engineering","","",""
"uuid:ee6a04b0-6fb6-4523-b64f-43e20f0c018f","http://resolver.tudelft.nl/uuid:ee6a04b0-6fb6-4523-b64f-43e20f0c018f","Investigating the Parameter-Driven Cathode Gas Diffusion of PEMFCs with a Piecewise Linearization Model","Gu, Siwen (Changzhou Institute of Technology Research for Solid State Lighting; Dalian University); Wang, Jiaan (Changzhou Institute of Technology Research for Solid State Lighting); You, X. (TU Delft RST/Fundamental Aspects of Materials and Energy); Zhuang, Yu (Dalian University of Technology)","","2023","Improving mass transfer in gas diffusion layers is critical to achieving high-performance proton-exchange membrane fuel cells (PEMFCs). Leaks through the interface between the gas and the membrane electrode assembly frame have been widely investigated, and the controllability of the cathode gas diffusion has not been achieved in most studies. In this study, we develop a structural parameter to investigate the controllability of the gas diffusion mechanism in the cathode in order to improve upon the design and performance of PEMFCs. This parameter accounts for the cathode gas diffusion layer porosity and carbon loading inside the catalyst layer. It is comprehensively calculated to relax the two segments’ distribution along three directions of the coordinate axis. The experimental and simulation results show that the obtained values of the parameter vary and change during voltage stabilization. According to the results, regardless of the materials in the cathode gas diffusion layer, the same steady-state voltage is obtained when the parameter is fixed. The cell could be controllably operated for a wide range of diffusion layer thicknesses by selecting the optimal parameter.","cathode; gas diffusion; PEMFC; simulation; structural parameter","en","journal article","","","","","","","","","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:3b17ffee-ec47-4e6a-9411-43ea2e0dc149","http://resolver.tudelft.nl/uuid:3b17ffee-ec47-4e6a-9411-43ea2e0dc149","Towards Efficient Personalized Driver Behavior Modeling with Machine Unlearning","Song, Q. (TU Delft Embedded Systems); Tan, Rui (Nanyang Technological University); Wang, J. (City University of Hong Kong)","","2023","Driver Behavior Modeling (DBM) aims to predict and model human driving behaviors, which is typically incorporated into the Advanced Driver Assistance System to enhance transportation safety and improve driving experience. Inverse reinforcement learning (IRL) is a prevailing DBM technique with the goal of modeling the driving policy by recovering an unknown internal reward function from human driver demonstrations. However, the latest IRL-based design is inefficient due to the laborious manual feature engineering processes. Besides, the reward function usually experiences increased prediction errors when deployed for unseen vehicles. In this paper, we propose a novel deep learning-based reward function for IRL-based DBM with efficient model personalization via machine unlearning. We evaluate our approach on a highway simulation constructed using the realistic human driving dataset NGSIM. We deploy our approach on both a server GPU and an embedded GPU. The evaluation results show that our approach achieves a higher prediction accuracy compared with the latest IRL-based DBM approach that uses a weighted sum of trajectory features as the reward function. Our model personalization method obtains the highest accuracy and lowest latency compared with the baselines.","Driver behavior modeling; inverse reinforcement learning; machine unlearning; model personalization; neural network","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Embedded Systems","","",""
"uuid:9d5c8743-b6ad-44f6-b06f-cd122f6ec15e","http://resolver.tudelft.nl/uuid:9d5c8743-b6ad-44f6-b06f-cd122f6ec15e","Evaluating building circularity in the early design phase","van der Zwaag, Marco (Student TU Delft); Wang, T. (TU Delft Design & Construction Management); Bakker, H.L.M. (TU Delft Integral Design & Management); van Nederveen, G.A. (TU Delft Integral Design & Management); Schuurman, A.C.B. (TU Delft Applied Mechanics); Bosma, Douwe (Bam infra)","","2023","Facing circular transition challenges, building circularity should be evaluated in the early design phase to reduce the risks of circular and environmental performance problems found in later project phases. However, due to the current design workflow, such practice is hindered because there is not enough information to evaluate building circularity in detail in the early design phases. An improved workflow to emphasize circularity more in the early design phase is thus needed. This research explores the current workflow and designs an improved workflow by developing an automated decision support system to assess early design phase building circularity with limited available information, aiming to improve the working efficiency and efficacy. This automated system helps in data-driven decision-making by integrating different data sources and presenting the calculated results interactively with business intelligence interfaces. The interfaces involve different types of evaluations based on the data availability in both schematic design and detail design sub-phases. It also visualizes the data quality and future scenarios. This system has been designed based on interviews and literature studies, and verified and validated with practitioners. This study serves as a starting point to rethink the workflow to improve circularity with currently available technology.","Building circularity index; Building information modelling; Circular design workflow; Decision support system; Evaluation tool; Material circularity indicator","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:907a6b1a-062c-429b-abb7-c8a83dc5562d","http://resolver.tudelft.nl/uuid:907a6b1a-062c-429b-abb7-c8a83dc5562d","The Covariation of Color and Orange Fluorescence Instabilities in Yellow Sapphires","Yang, Yunqi (China University of Geosciences, Wuhan; Hubei Gems and Jewelry Engineering Technology Research Center); Wang, C. (TU Delft Applied Geology; China University of Geosciences, Wuhan; Hubei Gems and Jewelry Engineering Technology Research Center); Wang, Chengsi (China University of Geosciences, Wuhan; Hubei Gems and Jewelry Engineering Technology Research Center); Shen, Xibing (China University of Geosciences, Wuhan; Beibu Gulf University); Yin, Ke (China University of Geosciences, Wuhan); Chen, Tao (China University of Geosciences, Wuhan; Hubei Gems and Jewelry Engineering Technology Research Center); Shen, Andy Hsitien (China University of Geosciences, Wuhan; Hubei Gems and Jewelry Engineering Technology Research Center); Algeo, Thomas J. (China University of Geosciences, Wuhan; University of Cincinnati); Hong, Hanlie (China University of Geosciences, Wuhan)","","2023","In recent years, some sapphires were found to fade in sunlight and to increase their color after UV irradiation. This unstable color phenomenon is attributed to the photochromism of corundum. The photochromic effect seriously affects the grading and evaluation of sapphires, although its mechanism is still uncertain. Here, we performed a set of photochromic experiments on sapphire specimens using a 254 nm shortwave UV light source and a D65 light source (which simulates sunlight) to generate different color states exhibiting characteristic absorption, emission, and excitation spectra. We observed that, for different color states, variation in the intensity of the absorption band at ~460 nm was consistent with that of orange fluorescence at 500–800 nm. This observation indicates a relationship between color instability and orange fluorescence. Peaks in excitation spectra at 320, 420, 490, 560, and 637 nm provide insight into the source(s) of excited orange fluorescence, which are related to different types of F-centers and Mg-trapped holes. We propose an explanation for the photochromic phenomenon: the color of photochromic yellow sapphire is the result of a variety of defects that release orange fluorescence simultaneously. Further, we hypothesize that the mechanism of photochromism in yellow sapphires is linked to electron transfer between F-centers and Mg-trapped holes.","corundum; defect; excitation spectrum; F-center; photochromic; trapped hole","en","journal article","","","","","","","","","","","Applied Geology","","",""
"uuid:99f9d133-522e-46f3-b32f-feb800dac4ff","http://resolver.tudelft.nl/uuid:99f9d133-522e-46f3-b32f-feb800dac4ff","Safe Zeroth-Order Optimization Using Linear Programs","Guo, Baiwei (EPFL Switzerland); Wang, Y. (TU Delft Team Riccardo Ferrari); Kamgarpour, Maryam (EPFL Switzerland); Ferrari-Trecate, Giancarlo (EPFL Switzerland)","","2023","To solve unmodeled optimization problems with hard constraints, this paper proposes a novel zeroth-order approach called Safe Zeroth-order Optimization using Linear Programs (SZO-LP). The SZO-LP method solves a linear program in each iteration to find a descent direction, followed by a step length determination. We prove that, under mild conditions, the iterates of SZO- LP have an accumulation point that is also the primal of a KKT pair. We then apply SZO-LP to solve an Optimal Power Flow (OPF) problem on the IEEE 30-bus system. The results demonstrate that SZO-LP requires less computation time and samples compared to state-of-the-art approaches.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-19","","","Team Riccardo Ferrari","","",""
"uuid:036a8038-cd0d-4756-bbce-77b62d131194","http://resolver.tudelft.nl/uuid:036a8038-cd0d-4756-bbce-77b62d131194","Molecular-scale characterization of groundwater treatment sludge from around the world: Implications for potential arsenic recovery","Wang, K. (Geological Survey of Denmark and Greenland); Holm, P. E. (University of Copenhagen); Trettenes, U. Brinkmann (VandCenter Syd); Bandaru, S. R.S. (University of California); van Halem, D. (TU Delft Sanitary Engineering); van Genuchten, C. M. (Geological Survey of Denmark and Greenland)","","2023","Iron (Fe)-based treatment methods are widely applied to remove carcinogenic arsenic (As) from drinking water, but generate toxic As-laden Fe (oxyhydr)oxide waste that has traditionally been ignored for resource recovery by the water sector. However, the European Commission recently classified As as a Critical Raw Material (CRM), thus providing new incentives to re-think As-laden groundwater treatment sludge. Before As recovery techniques can be developed for groundwater treatment waste, detailed information on its structure and composition is essential. To this end, we comprehensively characterized sludge generated from a variety of As-rich groundwater treatment plants in different geographic regions by combining a suite of macroscopic measurements, such as total digestions, leaching tests and BET surface area with molecular-scale solid-phase analysis by Fe and As K-edge X-ray absorption spectroscopy (XAS). We found that the As mass fraction of all samples ranged from ∼200–1200 mg As/kg (dry weight) and the phosphorous (P) content reached ∼0.5–2 mass%. Notably, our results indicated that the influent As level was a poor predictor of the As sludge content, with the highest As mass fractions (940–1200 mg As/kg) measured in sludge generated from treating low groundwater As levels (1.1–22 µg/L). The Fe K-edge XAS data revealed that all samples consisted of nanoscale Fe(III) precipitates with less structural order than ferrihydrite, which is consistent with their high BET surface area (up to >250 m2/g) and large As and P mass fractions. The As K-edge XAS data indicated As was present in all samples predominantly as As(V) bound to Fe(III) precipitates in the binuclear-corner sharing (2C) geometry. Overall, the similar structure and composition of all samples implies that As recovery methods optimized for one type of Fe-based treatment sludge can be applied to many groundwater treatment sludges. Our work provides a critical foundation for further research to develop resource recovery methods for As-rich waste.","Arsenic; Critical raw materials; Groundwater treatment sludge; Resource recovery","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-03-08","","","Sanitary Engineering","","",""
"uuid:e87b6981-743e-42f4-a2a3-cf658f685ebc","http://resolver.tudelft.nl/uuid:e87b6981-743e-42f4-a2a3-cf658f685ebc","Continual driver behaviour learning for connected vehicles and intelligent transportation systems: Framework, survey and challenges","Li, Zirui (Technische Universität Dresden; Beijing Institute of Technology); Gong, Cheng (Beijing Institute of Technology); Lin, Yunlong (Beijing Institute of Technology); Li, G. (TU Delft Transport and Planning); Wang, Xinwei (Queen Mary University of London); Lu, Chao (Beijing Institute of Technology); Wang, Miao (Baidu, Inc.); Chen, Shanzhi (China Information and Communication Technology Group Co., Ltd.); Gong, Jianwei (Beijing Institute of Technology)","","2023","Modelling, predicting and analysing driver behaviours are essential to advanced driver assistance systems (ADAS) and the comprehensive understanding of complex driving scenarios. Recently, with the development of deep learning (DL), numerous driver behaviour learning (DBL) methods have been proposed and applied in connected vehicles (CV) and intelligent transportation systems (ITS). This study provides a review of DBL, which mainly focuses on typical applications in CV and ITS. First, a comprehensive review of the state-of-the-art DBL is presented. Next, Given the constantly changing nature of real driving scenarios, most existing learning-based models may suffer from the so-called “catastrophic forgetting,” which refers to their inability to perform well in previously learned scenarios after acquiring new ones. As a solution to the aforementioned issue, this paper presents a framework for continual driver behaviour learning (CDBL) by leveraging continual learning technology. The proposed CDBL framework is demonstrated to outperform existing methods in behaviour prediction through a case study. Finally, future works, potential challenges and emerging trends in this area are highlighted.","Connected vehicles; Continual learning; Driver behaviours; Intelligent transportation systems; Machine learning","en","review","","","","","","","","","","","Transport and Planning","","",""
"uuid:6f79eb43-eebe-4134-9696-022d01fff7f0","http://resolver.tudelft.nl/uuid:6f79eb43-eebe-4134-9696-022d01fff7f0","Laser-Induced Graphene Formation on Chitosan Derivatives toward Ecofriendly Electronics","Huang, Qian Ming (Harbin Institute of Technology; Southern University of Science and Technology); Yang, Huiru (Harbin Institute of Technology; Southern University of Science and Technology); Wang, S. (TU Delft Bio-Electronics; Southern University of Science and Technology); Liu, X. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology); Tan, C. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology); Luo, Anxin (Southern University of Science and Technology); Xu, Siyuan (Southern University of Science and Technology); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Ye, H. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology)","","2023","Laser-induced graphene (LIG) has aroused a wide range of research interests ranging from micro-nano energy devices to the Internet of Things (IoT). Nevertheless, the non-degradability of most-used synthetic polymer carbon sources poses a serious threat to the environment. In this work, ecofriendly chitosan-based derivatives, including carboxymethyl chitosan (CMCS), chitosan oligosaccharide, and chitosan hydrochloride, are successfully converted into LIGs for the first time via a convenient one-step CO2 laser engraving at ambient air. The obtained LIGs are characterized by a three-dimensional hierarchical porous structure and exhibit good sheet conductivity. The consecutive carbonization and graphitization mechanism of target precursors induced by laser heat accumulation is also deeply discussed. Besides, based on a mechanically reliable LIG/CMCS composite film and tribo-negative acrylic/polyimide anti-layers, two contact-separation mode triboelectric nanogenerators are built and their power densities range from 1.44 to 2.48 mW cm-2. These devices with long cycle life can be used for low-frequency mechanical energy harvesting and commercial capacitance charging, which could be potentially applied in the wireless sensor network nodes. Such a family of chitosan derivatives paves a new route for LIG synthesis and provides new ideas for ecofriendly LIG electronics.","carbon precursor; chitosan derivatives; ecofriendly and biodegradability; laser-induced graphene; triboelectric nanogenerator","en","journal article","","","","","","","","","","","Bio-Electronics","","",""
"uuid:4aa9af42-27c4-4da7-83fe-2f0ab59f6e25","http://resolver.tudelft.nl/uuid:4aa9af42-27c4-4da7-83fe-2f0ab59f6e25","Patching sulfur vacancies: A versatile approach for achieving ultrasensitive gas sensors based on transition metal dichalcogenides","Liu, Xiangcheng (South China Normal University); Niu, Yue (South China Normal University; Great Bay University, Dongguan); Jin, Duo (South China Normal University); Zeng, Junwei (South China Normal University); Li, Wanjiang (South China Normal University); Li, Hao (South China Normal University); Lee, Yi Kuen (The Hong Kong University of Science and Technology); French, P.J. (TU Delft Bio-Electronics); Wang, Yao (South China Normal University)","","2023","Transition metal dichalcogenides (TMDCs) garner significant attention for their potential to create high-performance gas sensors. Despite their favorable properties such as tunable bandgap, high carrier mobility, and large surface-to-volume ratio, the performance of TMDCs devices is compromised by sulfur vacancies, which reduce carrier mobility. To mitigate this issue, we propose a simple and universal approach for patching sulfur vacancies, wherein thiol groups are inserted to repair sulfur vacancies. The sulfur vacancy patching (SVP) approach is applied to fabricate a MoS2-based gas sensor using mechanical exfoliation and all-dry transfer methods, and the resulting 4-nitrothiophenol (4NTP) repaired molybdenum disulfide (4NTP-MoS2) is prepared via a sample solution process. Our results show that 4NTP-MoS2 exhibits higher response (increased by 200 %) to ppb-level NO2 with shorter response/recovery times (61/82 s) and better selectivity at 25 °C compared to pristine MoS2. Notably, the limit of detection (LOD) toward NO2 of 4NTP-MoS2 is 10 ppb. Kelvin probe force microscopy (KPFM) and density functional theory (DFT) reveal that the improved gas sensing performance is mainly attributed to the 4NTP-induced n-doping effect on MoS2 and the corresponding increment of surface absorption energy to NO2. Additionally, our 4NTP-induced SVP approach is universal for enhancing gas sensing properties of other TMDCs, such as MoSe2, WS2, and WSe2.","2D materials; Gas sensing; N-doping; Patching sulfur vacancies; Transition metal dichalcogenides","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-17","","","Bio-Electronics","","",""
"uuid:de111788-28af-4da8-a99e-fc9b2587b753","http://resolver.tudelft.nl/uuid:de111788-28af-4da8-a99e-fc9b2587b753","High-resolution imaging of two radio quasars at the end of the reionization epoch","Perger, Krisztina (Konkoly Observatory Hungarian Academy of Sciences); Zhang, Yingkang (Chinese Academy of Sciences); Frey, Sándor (Konkoly Observatory Hungarian Academy of Sciences; Eötvös University); An, Tao (Chinese Academy of Sciences); Gabányi, Krisztina E. (Konkoly Observatory Hungarian Academy of Sciences; Eötvös University); Gurvits, L. (TU Delft Astrodynamics & Space Missions; Joint Institute for VLBI ERIC); Hwang, Chorng Yuan (National Central University Taiwan); Koptelova, Ekaterina (National Central University Taiwan); Paragi, Zsolt (Joint Institute for VLBI ERIC); Wang, Ailing (Chinese Academy of Sciences)","","2023","There are approximately 250 quasars discovered at redshift z ≥ 6, of which only a handful were detected in radio bands, and even fewer were imaged with the highest resolution very long baseline interferometry (VLBI) technique. Here we report the results of our dual-frequency observations with the Very Long Baseline Array (VLBA) of two such recently discovered quasars, VIKING J231818.35-311346.3 at z = 6.44 and FIRST J233153.20+112952.11 at z = 6.57. Both extremely distant sources were imaged with VLBI for the first time. The radio properties of the former are consistent with those of quasars with young radio jets. The latter has an UV/optical spectrum characteristic of BL Lac objects, of which no others have been found beyond redshift 4 so far. Our VLBA observations revealed a flat-spectrum compact radio source.","","en","journal article","","","","","","","","","","","Astrodynamics & Space Missions","","",""
"uuid:1f1ea706-0b77-43a9-9479-993cafebf1b9","http://resolver.tudelft.nl/uuid:1f1ea706-0b77-43a9-9479-993cafebf1b9","A novel GA-LSTM-based prediction method of ship energy usage based on the characteristics analysis of operational data","Wang, Kai (Dalian Maritime University); Hua, Yu (Dalian Maritime University); Huang, Lianzhong (Dalian Maritime University); Guo, Xin (Dalian Maritime University); Liu, Xing (Dalian Maritime University); Ma, Zhongmin (Dalian Maritime University); Ma, Ranqi (Dalian Maritime University); Jiang, X. (TU Delft Transport Engineering and Logistics)","","2023","Optimization of ship energy efficiency is an efficient measure to decrease fuel usage and emissions in the shipping industry. The accurate prediction model of ship energy usage is the basis to achieve optimization of ship energy efficiency. This study investigates the sequential properties of the actual voyage data from a VLOC. On this basis, a model for predicting ship energy consumption is established by adopting a LSTM neural network that has better prediction performance for sequential datasets. To further enhance the performance of the established LSTM-based model, the network structures and hyperparameters are optimized by using Genetic Algorithm. Lastly, the application analysis is conducted to validate the established GA-LSTM-based model for ship fuel usage prediction. The established model for ship energy usage shows a significant improvement in prediction accuracy, compared to the original LSTM-based model. Meanwhile, the developed prediction model is more accurate than the existing BP, SVR, and ARIMA-based energy consumption models. The prediction errors for the ship's operational energy efficiency adopting the established GA-LSTM-based model can reach as low as 0.29%. Therefore, the established model can effectively predict the ship fuel usage under different conditions, which is essential for the optimization and improvement of ship energy efficiency.","Energy consumption prediction; Genetic algorithm; LSTM neural network; Ship energy efficiency; Shipping decarbonization","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-26","","","Transport Engineering and Logistics","","",""
"uuid:feb5e4f9-770a-447f-bd41-571e992ad79a","http://resolver.tudelft.nl/uuid:feb5e4f9-770a-447f-bd41-571e992ad79a","Rapid extraction of pavement aggregate gradation based on point clouds using deep learning networks","Chen, Siyu (Southeast University); Chen, Can (Southeast University); Ma, Tao (Southeast University); Han, Chengjia (Southeast University; Nanyang Technological University); Luo, Haoyuan (Southeast University); Wang, Siqi (Southeast University); Gao, Y. (TU Delft Pavement Engineering); Yang, Yaowen (Nanyang Technological University)","","2023","Usage of asphalt mixture with poor gradation will most likely lead to pavement deficiency. There is a growing need for rapid and non-destructive methods to extract pavement aggregate gradation. In this study, a deep learning-based method that utilizes point clouds data for gradation extraction was proposed. Firstly, a data enhancement algorithm along with three data format conversion methods (aligned point cloud, voxel, and depth image) were proposed to preprocess the original collected point clouds. Subsequently, different neural network models were designed for each data format to extract gradation. Finally, a multi-feature fusion network was developed, which using extraction network as the backbone and additional auxiliary information. In the case study, the MAE loss of multi-feature fusion networks with PointNet, Vox-ResNet34 and GoogLeNet-v4 as the backbone respectively achieved 0.202, 0.142 and 0.046 on the test set, which means an estimation accuracy of more than 95% for the pavement aggregate gradation.","Aggregate gradation; Artificial neural networks; Asphalt pavement; Multi-feature fusion; Point clouds","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-20","","","Pavement Engineering","","",""
"uuid:9c7fb903-3abb-4641-be12-2662d43b9fb2","http://resolver.tudelft.nl/uuid:9c7fb903-3abb-4641-be12-2662d43b9fb2","Uncertainty quantification in a heterogeneous fluvial sandstone reservoir using GPU-based Monte Carlo simulation","Wang, Y. (TU Delft Reservoir Engineering; Qingdao University of Technology); Voskov, D.V. (TU Delft Reservoir Engineering; Stanford University); Daniilidis, Alexandros (TU Delft Reservoir Engineering); Khait, M. (TU Delft Reservoir Engineering; Stone Ridge Technology); Saeid, S. (TU Delft Reservoir Engineering); Bruhn, D.F. (TU Delft Reservoir Engineering; Fraunhofer IEG)","","2023","The efficient operation and management of a geothermal project can be largely affected by geological, physical, operational and economic uncertainties. Systematic uncertainty quantification (UQ) involving these parameters helps to determine the probability of the focused outputs, e.g., energy production, Net Present Value (NPV), etc. However, how to efficiently assess the specific impacts of different uncertain parameters on the outputs of a geothermal project is still not clear. In this study, we performed a comprehensive UQ to a low-enthalpy geothermal reservoir using the GPU implementation of the Delft Advanced Research Terra Simulator (DARTS) framework with stochastic Monte Carlo samplings of uncertain parameters. With processing the simulation results, large uncertainties have been found in the production temperature, pressure drop, produced energy and NPV. It is also clear from the analysis that salinity influences the producing energy and NPV via changing the amount of energy carried in the fluid. Our work shows that the uncertainty in NPV is much larger than that in produced energy, as more uncertain factors were encompassed in NPV evaluation. An attempt to substitute original 3D models with upscaled 2D models in UQ demonstrates significant differences in the stochastic response of these two approaches in representation of realistic heterogeneity. The GPU version of DARTS significantly improved the simulation performance, which guarantees the full set (10,000 times) UQ with a large model (circa 3.2 million cells) finished within a day. With this study, the importance of UQ to geothermal field development is comprehensively addressed. This work provides a framework for assessing the impacts of uncertain parameters on the concerning system output of a geothermal project and will facilitate analyses with similar procedures.","Energy production; Geothermal uncertainty quantification; GPU platform; Monte Carlo simulation; Net present value","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:5d1a2896-3467-4368-912b-16ee46ce1e41","http://resolver.tudelft.nl/uuid:5d1a2896-3467-4368-912b-16ee46ce1e41","Additive manufacturing of vascular stents","Li, Yageng (University of Science and Technology Beijing); Shi, Yixuan (University of Science and Technology Beijing); Lu, Yuchen (University of Science and Technology Beijing); Li, Xuan (University of Science and Technology Beijing); Zhou, J. (TU Delft Biomaterials & Tissue Biomechanics); Zadpoor, A.A. (TU Delft Biomaterials & Tissue Biomechanics); Wang, Luning (University of Science and Technology Beijing)","","2023","With the advancement of additive manufacturing (AM), customized vascular stents can now be fabricated to fit the curvatures and sizes of a narrowed or blocked blood vessel, thereby reducing the possibility of thrombosis and restenosis. More importantly, AM enables the design and fabrication of complex and functional stent unit cells that would otherwise be impossible to realize with conventional manufacturing techniques. Additionally, AM makes fast design iterations possible while also shortening the development time of vascular stents. This has led to the emergence of a new treatment paradigm in which custom and on-demand-fabricated stents will be used for just-in-time treatments. This review is focused on the recent advances in AM vascular stents aimed at meeting the mechanical and biological requirements. First, the biomaterials suitable for AM vascular stents are listed and briefly described. Second, we review the AM technologies that have been so far used to fabricate vascular stents as well as the performances they have achieved. Subsequently, the design criteria for the clinical application of AM vascular stents are discussed considering the currently encountered limitations in materials and AM techniques. Finally, the remaining challenges are highlighted and some future research directions are proposed to realize clinically-viable AM vascular stents. Statement of significance: Vascular stents have been widely used for the treatment of vascular disease. The recent progress in additive manufacturing (AM) has provided unprecedented opportunities for revolutionizing traditional vascular stents. In this manuscript, we review the applications of AM to the design and fabrication of vascular stents. This is an interdisciplinary subject area that has not been previously covered in the published review articles. Our objective is to not only present the state-of-the-art of AM biomaterials and technologies but to also critically assess the limitations and challenges that need to be overcome to speed up the clinical adoption of AM vascular stents with both anatomical superiority and mechanical and biological functionalities that exceed those of the currently available mass-produced devices.","Additive manufacturing; Biological performance; Biomaterial; Mechanical property; Vascular stent","en","review","","","","","","","","","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:6ef78897-e046-4139-a145-8c9e1f056247","http://resolver.tudelft.nl/uuid:6ef78897-e046-4139-a145-8c9e1f056247","A non-unit line protection method for MMC-HVDC grids based on the curvatures of backward traveling waves","Xie, F. (TU Delft Intelligent Electrical Power Grids; Xi’an Jiaotong University); Hao, Zhiguo (Xi’an Jiaotong University); Ye, Dongmeng (Xi’an Jiaotong University); Yang, Songhao (Xi’an Jiaotong University); Li, Chuanxi (XJ Electric); Dai, Guoan (XJ Electric); Zhang, Baohui (Xi’an Jiaotong University); Wang, Ting (School of Electrical and Electronic Engineering)","","2023","The existing protection techniques for high-voltage direct-current (HVDC) grids suffer from several shortcomings such as high sampling frequency, poor robustness, and reliance on simulation for threshold setting. To solve these problems, this paper proposes a non-unit protection method for modular multilevel converter (MMC)-based HVDC grids using the curvatures of backward traveling waves. To this end, the propagation characteristics of traveling waves and the boundary characteristics of DC lines are first studied, then the analytical expressions of backward traveling waves are derived. Moreover, the curvatures of backward traveling waves are analyzed. On this basis, a non-unit protection method is proposed, including zone selection, disturbance identification, and pole selection. At last, with a protection platform and a real-time digital simulator (RTDS) platform of the MMC-HVDC grid, the accuracy and the robustness of the proposed protection method are verified. The results show that the protection method can correctly identify faults with different distances and resistance in 1 ms and has strong robustness against transition resistance, sampling frequency, boundary value, noise, system topology, and line parameters.","Curvatures; HVDC grids; Modular multilevel converters; Non-unit protection; Traveling waves","en","journal article","","","","","","","","2024-01-08","","","Intelligent Electrical Power Grids","","",""
"uuid:4974ab34-8a3a-437e-9881-4c8726c119c5","http://resolver.tudelft.nl/uuid:4974ab34-8a3a-437e-9881-4c8726c119c5","Synchronization of Coupled Phase Oscillators with Stochastic Disturbances and the Cycle Space of the Graph","Xi, Kaihua (Shandong University); Wang, Zhen (Shandong University); Cheng, Aijie (Shandong University); Lin, H.X. (TU Delft Mathematical Physics); van Schuppen, J.H. (TU Delft Mathematical Physics); Zhang, Chenghui (Shandong University)","","2023","The synchronization stability of a complex network system of coupled phase oscillators is discussed. In case the network is affected by disturbances, a stochastic linearized system of the coupled phase oscillators may be used to determine the fluctuations of phase differences in the lines between the nodes and to identify the vulnerable lines that may lead to desynchronization. The main result is the derivation of the asymptotic variance matrices of the phase differences which characterizes the severity of the fluctuations. It is found that the cycle space of the graph of the system plays a role in this characterization. With theory of the cycle space, the effect of forming small cycles on the fluctuations is evaluated. It is proven that adding a new line or increasing the coupling strength of a line affects the fluctuations in the lines in any cycle including this line, while it does not affect the fluctuations in the other lines. In particular, if the phase differences at the synchronous state are not changed by these actions, then the affected fluctuations reduce.","asymptotic variance; cycle space of graphs; invariant probability distribution; Lyapunov equation; networked system; stochastic Gaussian system; synchronization stability","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:38229a32-8f74-47da-916d-83e27e576db1","http://resolver.tudelft.nl/uuid:38229a32-8f74-47da-916d-83e27e576db1","Use of thermal imaging to measure the quality of hand hygiene","Wang, C.W. (TU Delft Human-Centred Artificial Intelligence); Jiang, W. (Anhui Normal University); Yang, K. (University of Melbourne); Sarsenbayeva, Z. (University of Sydney); Tag, B. (Monash University); Dingler, T. (University of Melbourne); Goncalves, J. (University of Melbourne); Kostakos, V. (University of Melbourne)","","2023","Objectives: Hand hygiene has long been promoted as the most effective way to prevent the transmission of infection. However, due to low compliance and low quality of hand hygiene reported in previous studies, constant monitoring of hand hygiene compliance and quality among healthcare workers is crucial. This study investigated the feasibility of using a thermal camera with an RGB camera to detect hand coverage of alcohol-based formulation, thereby monitoring the quality of hand rubbing. Methods: In total, 32 participants were recruited to participate in this study. Participants were required to perform four types of hand rubbing to achieve different coverage of the alcohol-based formulation. After each task, participants' hands were photographed under a thermal camera and an RGB camera, while an ultraviolet (UV) test was used to provide the ground truth of hand coverage of alcohol-based formulation. U-Net was used to segment areas exposed to alcohol-based formulation from thermal images, and system performance was evaluated by comparing differences in coverage between thermal images and UV images in terms of accuracy and Dice coefficient. Results: This system found promising results in terms of accuracy (93.5%) and Dice coefficient (87.1%) when observations took place 10 s after hand rubbing. At 60 s after hand rubbing, accuracy and Dice coefficient were 92.4% and 85.7%. Conclusions: Thermal imaging has potential for accurate, constant and systematic monitoring of the quality of hand hygiene.","Hand hygiene; Thermal camera; Ultraviolet light; World Health Organization","en","journal article","","","","","","","","","","","Human-Centred Artificial Intelligence","","",""
"uuid:a5beb13b-56f8-426c-acd4-e6a29e50d20e","http://resolver.tudelft.nl/uuid:a5beb13b-56f8-426c-acd4-e6a29e50d20e","Wastewater-based epidemiology predicts COVID-19-induced weekly new hospital admissions in over 150 USA counties","Li, Xuan (University of Technology Sydney); Liu, Huan (University of Technology Sydney); Gao, Li (South East Water); Sherchan, Samendra P. (Morgan State University; Tulane University); Zhou, Ting (University of Technology Sydney); Khan, Stuart J. (University of New South Wales); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology); Wang, Qilin (University of Technology Sydney)","","2023","Although the coronavirus disease (COVID-19) emergency status is easing, the COVID-19 pandemic continues to affect healthcare systems globally. It is crucial to have a reliable and population-wide prediction tool for estimating COVID-19-induced hospital admissions. We evaluated the feasibility of using wastewater-based epidemiology (WBE) to predict COVID-19-induced weekly new hospitalizations in 159 counties across 45 states in the United States of America (USA), covering a population of nearly 100 million. Using county-level weekly wastewater surveillance data (over 20 months), WBE-based models were established through the random forest algorithm. WBE-based models accurately predicted the county-level weekly new admissions, allowing a preparation window of 1-4 weeks. In real applications, periodically updated WBE-based models showed good accuracy and transferability, with mean absolute error within 4-6 patients/100k population for upcoming weekly new hospitalization numbers. Our study demonstrated the potential of using WBE as an effective method to provide early warnings for healthcare systems.","","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:555d035f-deed-4d3c-912b-60a9c4c99969","http://resolver.tudelft.nl/uuid:555d035f-deed-4d3c-912b-60a9c4c99969","Physiomimetic biocompatibility evaluation of directly printed degradable porous iron implants using various cell types","Li, Y. (TU Delft Biomaterials & Tissue Biomechanics; University of Science and Technology Beijing); Pavanram, P. (University Hospital RWTH Aachen); Bühring, J. (Rheinisch-Westfälische Technische Hochschule); Rütten, S. (University Hospital RWTH Aachen); Schröder, K. U. (Rheinisch-Westfälische Technische Hochschule); Zhou, J. (TU Delft Biomaterials & Tissue Biomechanics); Pufe, T. (University Hospital RWTH Aachen); Wang, L. . (University of Science and Technology Beijing); Zadpoor, A.A. (TU Delft Biomaterials & Tissue Biomechanics); Jahr, H. (Rheinisch-Westfälische Technische Hochschule; University Hospital RWTH Aachen)","","2023","Additively manufactured (AM) degradable porous metallic biomaterials offer unique opportunities for satisfying the design requirements of an ideal bone substitute. Among the currently available biodegradable metals, iron has the highest elastic modulus, meaning that it would benefit the most from porous design. Given the successful preclinical applications of such biomaterials for the treatment of cardiovascular diseases, the moderate compatibility of AM porous iron with osteoblast-like cells, reported in earlier studies, has been surprising. This may be because, as opposed to static in vitro conditions, the biodegradation products of iron in vivo are transported away and excreted. To better mimic the in situ situations of biodegradable biomaterials after implantation, we compared the biodegradation behavior and cytocompatibility of AM porous iron under static conditions to the conditions with dynamic in situ-like fluid flow perfusion in a bioreactor. Furthermore, the compatibility of these scaffolds with four different cell types was evaluated to better understand the implications of these implants for the complex process of natural wound healing. These included endothelial cells, L929 fibroblasts, RAW264.7 macrophage-like cells, and osteoblastic MG-63 cells. The biodegradation rate of the scaffolds was significantly increased in the perfusion bioreactor as compared to static immersion. Under either condition, the compatibility with L929 cells was the best. Moreover, the compatibility with all the cell types was much enhanced under physiomimetic dynamic flow conditions as compared to static biodegradation. Our study highlights the importance of physiomimetic culture conditions and cell type selection when evaluating the cytocompatibility of degradable biomaterials in vitro. Statement of Significance: Additively manufactured (AM) degradable porous metals offer unique opportunities for the treatment of large bony defects. Despite the successful preclinical applications of biodegradable iron in the cardiovascular field, the moderate compatibility of AM porous iron with osteoblast-like cells was reported. To better mimic the in vivo condition, we compared the biodegradation behavior and cytocompatibility of AM porous iron under static condition to dynamic perfusion. Furthermore, the compatibility of these scaffolds with various cell types was evaluated to better simulate the process of natural wound healing. Our study suggests that AM porous iron holds great promise for orthopedic applications, while also highlighting the importance of physio-mimetic culture conditions and cell type selection when evaluating the cytocompatibility of degradable biomaterials in vitro.","Additive manufacturing; Biocompatibility; Biodegradation; MG-63, L929, HUVEC, RAW264.7; Perfusion bioreactor; Porous iron","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-01","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:30c50dd2-48bc-4359-aacc-918b69edd42c","http://resolver.tudelft.nl/uuid:30c50dd2-48bc-4359-aacc-918b69edd42c","Sensor Fusion and Advanced Controller for Connected and Automated Vehicles","Li, Boyuan (Zhejiang Lab); Wang, Yafei (Shanghai Jiao Tong University); Papaioannou, G. (TU Delft Intelligent Vehicles); Du, Haiping (University of Wollongong)","","2023","","","en","contribution to periodical","","","","","","","","","","","Intelligent Vehicles","","",""
"uuid:80afdb88-bda1-4613-90e2-42a7113acb76","http://resolver.tudelft.nl/uuid:80afdb88-bda1-4613-90e2-42a7113acb76","Deep Bayesian survival analysis of rail useful lifetime","Zeng, Cheng (The University of Newcastle, Australia); Huang, Jinsong (The University of Newcastle, Australia); Wang, H. (TU Delft Railway Engineering); Xie, Jiawei (The University of Newcastle, Australia); Zhang, Yuting (The University of Newcastle, Australia)","","2023","Reliable estimation of rail useful lifetime can provide valuable information for predictive maintenance in railway systems. However, in most cases, lifetime data is incomplete because not all pieces of rail experience failure by the end of the study horizon, a problem known as censoring. Ignoring or otherwise mistreating the censored cases might lead to false conclusions. Survival approach is particularly designed to handle censored data for analysing the expected duration of time until one event occurs, which is rail failure in this paper. This paper proposes a deep Bayesian survival approach named BNN-Surv to properly handle censored data for rail useful lifetime modelling. The proposed BNN-Surv model applies the deep neural network in the survival approach to capture the non-linear relationship between covariates and rail useful lifetime. To consider and quantify uncertainty in the model, Monte Carlo dropout, regarded as the approximate Bayesian inference, is incorporated into the deep neural network to provide the confidence interval of the estimated lifetime. The proposed approach is implemented on a four-year dataset including track geometry monitoring data, track characteristics data, various types of defect data, and maintenance and replacement (M&R) data collected from a section of railway tracks in Australia. Through extensive evaluation, including Concordance index (C-index) and root mean square error (RMSE) for evaluating model performance, as well as a proposed CW-index for evaluating uncertainty estimations, the effectiveness of the proposed approach is confirmed. The results show that, compared with other commonly used models, the proposed approach can achieve the best concordance index (C-index) of 0.80, and the estimated rail useful lifetimes are closer to real lifetimes. In addition, the proposed approach can provide the confidence interval of the estimated lifetime, with a correct coverage of 81% of the actual lifetime when the confidence interval is 1.38, which is more useful than point estimates in decision-making and maintenance planning of railroad systems.","Bayesian inference; Deep neural networks; Rail useful lifetime; Survival analysis","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:bbc7ca8a-af0d-46e7-b8e1-717ed3fd931f","http://resolver.tudelft.nl/uuid:bbc7ca8a-af0d-46e7-b8e1-717ed3fd931f","Dynamic Growth of Macroscopically Structured Supramolecular Hydrogels through Orchestrated Reaction-Diffusion","Wang, Hucheng (East China University of Science and Technology); Fu, Xiaoming (East China University of Science and Technology); Gu, Guanyao (East China University of Science and Technology); Bai, Shengyu (East China University of Science and Technology); Li, Runlai (National University of Singapore); Zhong, Weimin (East China University of Science and Technology); Guo, Xuhong (East China University of Science and Technology); Eelkema, R. (TU Delft ChemE/Advanced Soft Matter); van Esch, J.H. (TU Delft ChemE/Advanced Soft Matter); Cao, Zhixing (East China University of Science and Technology); Wang, Yiming (East China University of Science and Technology)","","2023","Living organisms are capable of dynamically changing their structures for adaptive functions through sophisticated reaction-diffusion processes. Here we show how active supramolecular hydrogels with programmable lifetimes and macroscopic structures can be created by relying on a simple reaction-diffusion strategy. Two hydrogel precursors (poly(acrylic acid) PAA/CaCl2 and Na2CO3) diffuse from different locations and generate amorphous calcium carbonate (ACC) nanoparticles at the diffusional fronts, leading to the formation of hydrogel structures driven by electrostatic interactions between PAA and ACC nanoparticles. Interestingly, the formed hydrogels are capable of autonomously disintegrating over time because of a delayed influx of electrostatic-interaction inhibitors (NaCl). The hydrogel growth process is well explained by a reaction-diffusion model which offers a theoretical means to program the dynamic growth of structured hydrogels. Furthermore, we demonstrate a conceptual access to dynamic information storage in soft materials using the developed reaction-diffusion strategy. This work may serve as a starting point for the development of life-like materials with adaptive structures and functionalities.","Hydrogels; Non-Equilibrium Systems; Reaction-Diffusion; Self-Assembly; Supramolecular Materials","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-03-06","","","ChemE/Advanced Soft Matter","","",""
"uuid:b4fa45a1-9c9e-4938-8504-3c6b19ce28fa","http://resolver.tudelft.nl/uuid:b4fa45a1-9c9e-4938-8504-3c6b19ce28fa","基于注意力机制的城市轨道交通网络级多步短时客流时空综合预测模型","Zhang, Jinlei (Beijing Jiaotong University); Chen, Yijie (Beijing Jiaotong University); Krishnakumari, P.K. (TU Delft Transport and Planning); Jin, Guangyin (National University of Defense Technology); Wang, Chengcheng; Yang, Lixing (Beijing Jiaotong University)","","2023","Accurate and reliable short- term passenger flow prediction can support operations and decision-making of the URT system from multiple perspectives. In this paper, we propose a URT multi- step short- term passenger flow prediction model at the network level based on a Transformer-based LSTM network, Depth-wise Attention Block, and CNN network, named as Spatial- Temporal Integrated Prediction Model (STIPM). The STIPM comprises three branches. The first branch takes time- series inflow data as input, and a Transformer-based LSTM network is selected to extract the temporal correlations. The second one takes timestep- based OD data as input, and many spatial and temporal features are captured using Depth- wise Attention Blocks. Meanwhile, timestep- based OD data can better include inter- station relations and global information. The third branch takes Point of Interest data (POI) as input and CNN network is utilized for spatiotemporal features extraction, which can also become the bridge between spatial and temporal features. Moreover, the“Multi-inputmulti- output Strategy”for multi- step prediction is used to obtain a longer prediction period and more detailed information under a relatively high forecasting accuracy. The STIPM is applied to two large- scale real- world datasets from the URT system, and the obtained prediction results are compared with ten baselines and four variants from itself, in which STIPM model achieves highest prediction accuracy indicated by RMSE, MAE, and WMAPE evaluations, which demonstrates the superiority and robustness of the STIPM.","deep learning; features fusion; multi-step forecasting; short-term passenger forecasting; spatiotemporal features mining; traffic big-data; urban Rail Transit","zh","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-23","","","Transport and Planning","","",""
"uuid:046880f9-39e1-44e3-8138-ffe45babfb8c","http://resolver.tudelft.nl/uuid:046880f9-39e1-44e3-8138-ffe45babfb8c","Solvent modulation, microstructure evaluation, process optimization, and nanoindentation analysis of micro-Cu@Ag core–shell sintering paste for power electronics packaging","Chen, Haixue (Fudan University); Wang, Xinyue (Fudan University); Zeng, Zejun (Fudan University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Zhang, Jing (Heraeus Materials Technology); Liu, Pan (Fudan University; Research Institute of Fudan University, Ningbo)","","2023","With the development of electronic technology towards high power, miniaturization, and system integration, power electronic packaging is facing increasing challenges, especially for die attachment. This research aims to explore silver-coated copper (Cu@Ag) paste with sufficient mechanical properties and high-temperature reliability, as an alternative solution for silver sintering with lower cost. Firstly, micro-Cu@Ag sintering pastes were investigated under four kinds of polyol-based solvent systems and two types of particle morphologies, which included sphere-type (SCu@Ag) and flake-type (FCu@Ag). Sintering performance and microstructural evolution were compared and analyzed. Notably, sintered joints employing the terpineol–polyethylene glycol solvent system and flake-type morphology displayed a denser microstructure in comparison to SCu@Ag joints. Its bonding strength reached 36.15 MPa, which was approximately 20% higher than SCu@Ag joints. Subsequently, the influence of key sintering process parameters on Cu@Ag joints was analyzed, including sintering temperature, pressure and time. Additionally, high-temperature aging and thermal cycling tests were conducted on the optimized Cu@Ag joints to assess their reliability. Finally, the micromechanical properties of Cu@Ag joints before and after high-temperature aging were further evaluated by nanoindentation including creep properties. The elastoplastic constitutive models of Cu@Ag sintered materials with different particle morphologies were constructed, providing valuable insights for reliability evaluation. The results indicated that FCu@Ag joints exhibited satisfactory creep resistance and high-temperature reliability. In conclusion, the FCu@Ag micro-paste based on the terpineol–polyethylene glycol solvent system proposed in this study demonstrated sufficient bonding strength, high reliability, and adequate mechanical properties as an attractive solution for high-temperature power electronics packaging.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-21","","","Electronic Components, Technology and Materials","","",""
"uuid:7528448c-99ca-445f-8cfa-b28faf5c4553","http://resolver.tudelft.nl/uuid:7528448c-99ca-445f-8cfa-b28faf5c4553","Pseudocapacitive gels based on conjugated polyelectrolytes: thickness and ion diffusion limitations","Vázquez, Ricardo Javier (National University of Singapore); Quek, Glenn (National University of Singapore); Jiang, Yan (National University of Singapore); Rui Peng, Benjamin Yip (National University of Singapore); McCuskey, Samantha R. (National University of Singapore; Nanyang Technological University); Ohayon, David (National University of Singapore); Kundukad, Binu (Nanyang Technological University); Wang, Xuehang (TU Delft RST/Storage of Electrochemical Energy); Bazan, Guillermo C. (National University of Singapore; Nanyang Technological University)","","2023","Conjugated polymer hydrogels (CPHs) are emerging pseudocapacitive materials capable of forming redox-active hydrogels. Current efforts focus on increasing their areal capacitance (CAreal) and cycling stabilities by using binders tolerant to H2SO4-based electrolytes, while alternatives in more environmentally friendly electrolytes underperform due to low-capacity values. Herein, we demonstrate that it is possible to use conjugated polyelectrolyte (CPE), namely CPE-K, to create a single-component binder-free pseudocapacitive gel in environmentally friendly electrolytes (2 M: NaCl, MgCl2, and MgSO4), with CAreal 1.9 times larger than those reported for single-component binder-free CPHs. The resulting pseudocapacitive gel exhibited CAreal (523 mF cm−2 at 0.25 mA cm−2) scalable with its thickness in NaCl electrolytes, providing an attractive solution to improve the capacitance of devices while maintaining a minimal charge-collecting electrode surface footprint. In addition, the CPE-K gel demonstrates 86% capacitance retention after 100 000 cycles at 10 mA cm−2, which is higher than those reported for conventional state-of-the-art conjugated polymers. Electrochemical characterization revealed that CAreal at all cycling rates tested is proportional to dThk up to 750 μm, primarily due to facile ionic diffusion within the 3D conductive network of the gel. Thicker electrodes (dThk = 1250 μm) can be operated at a rate of 15 mA cm−2 with minimal capacity loss. These results demonstrate the potential applications of self-doped CPE gels in designing the next generation of multi-functional electrochemical energy storage and conversion technologies for targeting high energy and power density applications.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-11","","","RST/Storage of Electrochemical Energy","","",""
"uuid:efe55fd8-7f5e-454d-840b-f84e8504c696","http://resolver.tudelft.nl/uuid:efe55fd8-7f5e-454d-840b-f84e8504c696","Designing an enzyme assembly line for green cascade processes using bio-orthogonal chemistry","Qiao, Li (Hangzhou Normal University); Luo, Zhiyuan (Hangzhou Normal University; Shanghai University of Traditional Chinese Medicine); Wang, Ru (Hangzhou Normal University); Pei, Xiaolin (Hangzhou Normal University); Wu, Shujiao (Hangzhou Normal University); Chen, Haomin (Hangzhou Normal University); Xie, Tian (Hangzhou Normal University; Shanghai University of Traditional Chinese Medicine); Sheldon, R.A. (TU Delft BT/Biocatalysis; University of Witwatersrand); Wang, Anming (Hangzhou Normal University)","","2023","Two non-canonical amino acids (ncAAs) with bio-orthogonal reactive groups, namely, p-azido-l-phenylalanine (p-AzF) and p-propargyloxy-l-phenylalanine (p-PaF), were genetically inserted into an aldo-keto reductase (AKR) and an alcohol dehydrogenase (ADH), respectively, at two preselected sites for each enzyme. The variants were expressed in the genome recoded bacterium Escherichia coli C321.ΔA. Supernatants of the individual cell lysates were subsequently mixed to produce orderly combi-crosslinked enzymes (O-CLEs) of AKR and ADH by co-polymerization of the two variants through their reactive bio-orthogonal groups. The site-specific cross-linked enzymes (S-CLEs) and cross-linked enzyme aggregates (CLEAs) were produced using dibenzocycloocta-4a,6a-diene-5,11-diyne (DBA) and glutaraldehyde as the crosslinking agent, respectively. The catalytic efficiencies of the O-CLEs, S-CLEs and combi-CLEAs were determined using the water soluble dihydro-4, 4-dimethyl-2, 3-furandione as a surrogate substrate in aqueous solution at 37 °C. The O-CLEs exhibited the highest catalytic efficiency (Kcat/KM = 11.36 S−1 mM−1) that was 4.24 and 22.27 times that of S-CLEs and combi-CLEAs, respectively. In the asymmetric cascade synthesis of (R)-1-(2-chlorophenyl) ethanol the product yield after 14 h using the O-CLEs, S-CLEs and the combi-CLEAs was 93%, 55% and 16%, respectively. Moreover, high activities and selectivity (ee > 99.99%) were maintained at high substrate concentrations in prolonged operation.","","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:64a44b59-c78e-49c9-bd44-f24aea2fbd6c","http://resolver.tudelft.nl/uuid:64a44b59-c78e-49c9-bd44-f24aea2fbd6c","Climate change - induced hazards on touristic island beaches: Cyprus, Eastern Mediterranean","Monioudi, Isavela N. (University of the Aegean); Velegrakis, Adonis F. (University of the Aegean); Chatzistratis, Dimitris (University of the Aegean); Vousdoukas, Michalis I. (University of the Aegean); Savva, Christos (University of the Aegean); Wang, Dandan (Zhejiang Ocean University); Bove, Gerald (State University of New York at Oneonta); Paprotny, D. (Potsdam Institute for Climate Impact Research); Morales Napoles, O. (TU Delft Hydraulic Structures and Flood Risk)","","2023","This contribution presents an assessment at a regional (island) scale of the beach erosion due to storm events under Climate Change. The approach adopted to assess beach erosion at the island scale consisted of three modules. First, the location, dimensions and other attributes of the Cypriot beaches were recorded on the basis of widely-available satellite imagery. Secondly, sea levels and waves were modeled along the coast under different climatic scenarios and dates in the 21st century. Finally, using these projections beach retreat due to the relative mean sea level rise (RSLR) and extreme sea levels (ESLs) was estimated using ensembles of analytical and numerical cross-shore morphodynamic models, respectively. Extreme sea levels (ESLs) were projected to (a) increase by up to 60% in 2100 from their baseline (2000) levels, and (b) vary along the coast, with the highest ESLs (and corresponding waves) projected for the southern and western coasts. The mostly narrow Cypriot beaches (91% recorded maximum widths of < 50 m) showed increased exposure to erosion. In 2100, about 47% and 72% (based on the median model estimates) of the 241 unprotected Cypriot beaches will be permanently eroded, due to mean sea level rise (SLR), to 50% of their present maximum width, depending on the scenario. In addition to the long-term erosion due to SLR, severe storm erosion is projected by 2050 even under the RCP4.5 scenario; the 100-year extreme sea level event (ESL100) may overwhelm (at least temporarily) 49% of the currently unprotected Cypriot beaches without effective adaptation responses, with the most exposed beaches located along the northern coast. As the beach carrying capacity and hedonic value will be severely compromised, effective adaptation policies and technical measures will be urgently required.","beach erosion; climate change impacts; extreme sea levels; island beaches; sea level rise; shoreline retreat","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:57bfca85-9ee5-470f-b848-4c306335ed70","http://resolver.tudelft.nl/uuid:57bfca85-9ee5-470f-b848-4c306335ed70","Experimental study of dynamic response of passive flapping hydrofoil in regular wave","Wang, Junxian (Cranfield University); Santhosh, Sabin (Cranfield University); Colomés, Oriol (TU Delft Offshore Engineering); Capaldo, Matteo (TotalEnergies); Yang, Liang (Cranfield University)","","2023","The hydrofoil harnesses wave energy and converts it into thrust. In this paper, we present the results of the first experimental study investigating the dynamic behavior of a fully passive foil with spring-loaded pitch and heave in regular waves. Our study shows that the real-time load signal is multi-harmonic with strong superposition, directly proving the robust energy harvesting performance due to the restoring springs. By interpreting the hydrofoil's pose and path from an image sequence captured underwater, we conclude the dynamic evolution of the fully passive hydrofoil interacting with regular waves. The hydrofoil's dynamics exhibit asymmetric surge, pitch, and heave in a motion cycle. Furthermore, we employ a pixel capturing algorithm with self-correction utility to quantify the hydrofoil's forward displacement from the image sequence of the moving carriage. These findings provide valuable insight into the performance and potential of hydrofoils for marine propulsion.","Energy harvesting; Wave power; Spring stiffness; Sensors; Wave mechanics; Fluid dynamics","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-26","","","Offshore Engineering","","",""
"uuid:ebf4b696-c291-4a4b-9bc2-29654d8fc282","http://resolver.tudelft.nl/uuid:ebf4b696-c291-4a4b-9bc2-29654d8fc282","Bloch-Lorentz magnetoresistance oscillations in delafossites","Vilkelis, K. (TU Delft QRD/Wimmer Group; Kavli institute of nanoscience Delft; QuTech); Wang, L. (TU Delft QN/Akhmerov Group; Kavli institute of nanoscience Delft); Akhmerov, A.R. (TU Delft QN/Akhmerov Group; Kavli institute of nanoscience Delft)","","2023","Recent measurements of the out-of-plane magnetoresistance of delafossites (PdCoO2 and PtCoO2) observed oscillations closely resembling the Aharonov-Bohm effect. Here, we show that the magnetoresistance oscillations are explained by the Bloch-like oscillations of the out-of-plane electron trajectories. We develop a semiclassical theory of these Bloch-Lorentz oscillations and show that they are a consequence of the ballistic motion and quasi-2D dispersion of delafossites. Our model identifies the sample wall scattering to be the most likely factor limiting the visibility of these Bloch-Lorentz oscillations in existing experiments.","","en","journal article","","","","","","","","","","","QRD/Wimmer Group","","",""
"uuid:bd3245ff-d66b-494d-ac99-7ad2aa43f32c","http://resolver.tudelft.nl/uuid:bd3245ff-d66b-494d-ac99-7ad2aa43f32c","Organizational structure and dynamic capabilities on business model innovation in project-driven enterprises: evidence from the construction industry","Wang, D. (TU Delft Statistics; Chongqing University); Huang, R. (TU Delft Design & Construction Management; Chongqing University); Li, Kaijian (Chongqing University); Shrestha, Asheem (Deakin University)","","2023","Purpose: Flexibility and efficiency are dual attributes of the organizational structure that are crucial for project-driven enterprises to achieve sustainable development in a dynamic environment. However, there is a lack of research on the patterns by which the dual attributes of a project-driven enterprise’s organizational structure affect business model innovation. Employing organizational theory, this study aims to assess the mediating mechanisms and dynamic capabilities through which the dual attributes of the organizational structure influence business model innovation in project-driven enterprises. Design/methodology/approach: Data were collected from 242 employees from four project-driven companies across 26 cities (e.g. Beijing, Tianjin, Guangzhou and Shenzhen) in China. Structural equation modeling revealed the relationship between organizational structure’s dual attributes and business model innovation. Findings: The findings show that the dual attributes (flexibility and efficiency) of the organizational structure have positive impacts on business model innovation. Moreover, dynamic capabilities mediate the relationship between the dual attributes and business model innovation in project-driven enterprises. Originality/value: This study provides contributions to innovation research in the context of project-driven enterprises by revealing the influence of organizational structure on business model innovation through the firms’ dynamic capabilities. Such knowledge can enable managers of project-driven enterprises to develop effective interventions to promote business model innovation.","Business model innovation; Dynamic capabilities; Organizational efficiency; Organizational flexibility; Project-driven enterprise","en","journal article","","","","","","","","2024-01-01","","","Statistics","","",""
"uuid:602dff4a-0aec-4ad0-9e59-82553541ef5f","http://resolver.tudelft.nl/uuid:602dff4a-0aec-4ad0-9e59-82553541ef5f","Harnessing Large Language Models for Cognitive Assistants in Factories","Kernan Freire, S. (TU Delft Internet of Things); Foosherian, Mina (University of Bremen); Wang, C.W. (TU Delft Human-Centred Artificial Intelligence); Niforatos, E. (TU Delft Internet of Things)","","2023","As agile manufacturing expands and workforce mobility increases, the importance of efficient knowledge transfer among factory workers grows. Cognitive Assistants (CAs) with Large Language Models (LLMs), like GPT-3.5, can bridge knowledge gaps and improve worker performance in manufacturing settings. This study investigates the opportunities, risks, and user acceptance of LLM-powered CAs in two factory contexts: textile and detergent production. Several opportunities and risks are identified through a literature review, proof-of-concept implementation, and focus group sessions. Factory representatives raise concerns regarding data security, privacy, and the reliability of LLMs in high-stake environments. By following design guidelines regarding persistent memory, real-time data integration, security, privacy, and ethical concerns, LLM-powered CAs can become valuable assets in manufacturing settings and other industries.","cognitive assistant; conversational user interfaces; human-centered AI; industry 5.0; knowledge management; knowledge sharing","en","conference paper","Association for Computing Machinery (ACM)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-19","","","Internet of Things","","",""
"uuid:1ca59942-9830-48d9-8f6a-87d5485d20cb","http://resolver.tudelft.nl/uuid:1ca59942-9830-48d9-8f6a-87d5485d20cb","Surface preparations and durability of iron-based shape memory alloy adhesively-bonded joints","Pichler, Niels (ETH Zürich); Wang, Wandong (Northwestern Polytechnical University); Poulis, J.A. (TU Delft Structural Integrity & Composites); Ghafoori, Elyas (Leibniz Universität)","","2023","Developing a bonded prestressed solution for strengthening structures utilizing an iron-based shape memory alloy (Fe-SMA), is of significant interest. This study is the first systematic investigation of adhesively-bonded Fe-SMA joints to achieve complete cohesive failure, which is an essential prerequisite for bond integrity. The Fe-SMA surface was prepared by combining UV/ozone exposure (UV), sol–gel (SG), and primers (PC, PNC), and the failure mode of the joint was investigated using the floating-roller peel test. Furthermore, the joint durability was studied through artificial aging using a salt spray cabinet. Cohesive failure was obtained for all investigated adhesives, and the effect of every surface preparation step was described. The application of sol–gel was found to be a crucial step in obtaining complete adhesive failure.","Durability; Iron-based shape memory alloy; Primers and coupling agents; Surface treatment","en","journal article","","","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:7c05309d-821e-4ed8-a765-656ecdc2a954","http://resolver.tudelft.nl/uuid:7c05309d-821e-4ed8-a765-656ecdc2a954","Simulation of CO2 Storage Using a Parameterization Method for Essential Trapping Physics: FluidFlower Benchmark Study","Wang, Y. (TU Delft Numerical Analysis; China University of Geosciences, Wuhan); Zhang, Z. (TU Delft Numerical Analysis); Vuik, Cornelis (TU Delft Delft Institute of Applied Mathematics); Hajibeygi, H. (TU Delft Reservoir Engineering)","","2023","An efficient compositional framework is developed for simulation of CO 2 storage in saline aquifers during a full-cycle injection, migration and post-migration processes. Essential trapping mechanisms, including structural, dissolution, and residual trapping, which operate at different time scales, are accurately captured in the presented unified framework. In particular, a parameterization method is proposed to efficiently describe the relevant physical processes. The proposed framework is validated by comparing the dynamics of gravity-induced convective transport with that reported in the literature. Results show good agreement for both the characteristics of descending fingers and the associated dissolution rate. The developed simulator is then applied to study the FluidFlower benchmark model. An experimental setup with heterogeneous geological layers is discretized into a two-dimensional computational domain where numerical simulation is performed. Impacts of hysteresis and the diffusion of CO 2 in liquid phase on the migration and trapping of CO 2 plume are investigated. Inclusion of the hysteresis effect does not affect plume migration in this benchmark model, whereas diffusion plays an important role in promoting convective mixing. This work casts a promising approach to predict the migration of the CO 2 plume, and to assess the amount of trapping from different mechanisms for long-term CO 2 storage.","Compositional simulation; Convective mixing; Geological CO storage; Hysteresis; Porous media","en","journal article","","","","","","","","","","","Numerical Analysis","","",""
"uuid:8ec5c395-a0f4-42a2-805d-c99d66ae3721","http://resolver.tudelft.nl/uuid:8ec5c395-a0f4-42a2-805d-c99d66ae3721","Combined CNN and RNN Neural Networks for GPR Detection of Railway Subgrade Diseases","Liu, Huan (China Academy of Railway Sciences; China University of Geosciences); Wang, Shilei (China Academy of Railway Sciences); Jing, Guoqing (Beijing Jiaotong University); Yu, Ziye (China Earthquake Administration); Yang, Jin (China University of Geosciences); Zhang, Yong (China Academy of Railway Sciences); Guo, Y. (TU Delft Railway Engineering)","","2023","Vehicle-mounted ground-penetrating radar (GPR) has been used to non-destructively inspect and evaluate railway subgrade conditions. However, existing GPR data processing and interpretation methods mostly rely on time-consuming manual interpretation, and limited studies have applied machine learning methods. GPR data are complex, high-dimensional, and redundant, in particular with non-negligible noises, for which traditional machine learning methods are not effective when applied to GPR data processing and interpretation. To solve this problem, deep learning is more suitable to process large amounts of training data, as well as to perform better data interpretation. In this study, we proposed a novel deep learning method to process GPR data, the CRNN network, which combines convolutional neural networks (CNN) and recurrent neural networks (RNN). The CNN processes raw GPR waveform data from signal channels, and the RNN processes features from multiple channels. The results show that the CRNN network achieves a higher precision at 83.4%, with a recall of 77.3%. Compared to the traditional machine learning method, the CRNN is 5.2 times faster and has a smaller size of 2.6 MB (traditional machine learning method: 104.0 MB). Our research output has demonstrated that the developed deep learning method improves the efficiency and accuracy of railway subgrade condition evaluation.","CNN; GPR; ground-penetrating radar; RNN; subgrade anomalies","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:db818f60-d125-4f25-9b39-fe42589c89a7","http://resolver.tudelft.nl/uuid:db818f60-d125-4f25-9b39-fe42589c89a7","When VLC Meets Under-Screen Camera","Ye, Hanting (TU Delft Embedded Systems); Xiong, Jie (University of Massachusetts Amherst); Wang, Q. (TU Delft Embedded Systems)","","2023","While radio communication still dominates in 5G, light and radios are expected to complement each other in the coming 6G networks. Visible Light Communication (VLC) is therefore attracting a tremendous amount of attention from both academia and industry. Recent studies showed that the front camera of pervasive smartphones is an ideal candidate to serve as the VLC receiver. While promising, we observe a recent trend with smartphones that can greatly hinder the adoption of smartphones for VLC, i.e., smartphones are moving towards full-screen for the best user experience. This trend forces front cameras to be placed under the devices' screen - -leading to the so-called Under-Screen Camera (USC) - -but we observe a severe performance degradation in VLC with USC: the transmission range is reduced from a few meters to merely 0.04 m, and the throughput is decreased by more than 90%. To address this issue, we leverage the unique spatiotemporal characteristics of the rolling shutter effect on USC to design a pixel-sweeping algorithm to identify the sampling points with minimal interference from the translucent screen. We further propose a novel slope-boosting demodulation method to deal with color shift brought by the leakage interference. We build a proof-of-concept prototype using two commercial smart-phones. Experiment results show that our proposed design reduces the BER by two orders of magnitude on average and improves the data rate by 59×: from 914 b/s to 54.43 kb/s. The transmission range is extended by roughly 100×: from 0.04 m to 4.2 m.","color-shift keying; full-screen; optical camera communication; through-screen VLC; translucent screen; under-screen camera","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Embedded Systems","","",""
"uuid:efae1187-df0b-4dc0-8eb0-b72f36048a9d","http://resolver.tudelft.nl/uuid:efae1187-df0b-4dc0-8eb0-b72f36048a9d","Effect of epoxy resin addition on properties and corrosion behavior of sintered joints in power modules serviced offshore","Wang, Xinyue (Fudan University); Yang, Zhoudong (Fudan University); Wang, Boya (Fudan University); Chen, Wei (Fudan University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Zhang, Jing (Heraeus Materials Technology Shanghai Ltd.); Fan, J. (TU Delft Electronic Components, Technology and Materials; Fudan University); Liu, P. (TU Delft Electronic Components, Technology and Materials; Fudan University)","","2023","Power modules applied in offshore applications are facing risks of corrosion failures on die-attach materials due to high humidity and H2S exposure. To investigate such corrosion behavior for sintered die-attach materials, we conducted a study with four groups of samples fabricated using copper and silver metal particles under different solvent systems. Such samples were firstly subjected to high-humidity-H2S conditions for 168 h to simulate the harsh offshore environment. After undergoing corrosion, the primary compounds formed were CuO/Cu2O and Ag2S through SEM, XRD, and XPS analysis. Notably, the incorporation of epoxy resin into sintered copper joints resulted in a remarkable reduction in corrosion and a substantial improvement in electrical conductivity after the reaction. In contrast, while the addition of epoxy did not evidently reduce corrosion in silver joints, it did lead to a significant increase in shear strength. Furthermore, to gain further insights into the effect of epoxy resin on corrosion behavior, electrochemical analysis, and molecular dynamics simulations were conducted. Finally, the mechanical reliability of the corroded copper and silver joints was evaluated through thermal shock tests. In summary, sintered copper joints exhibited better anti-corrosion behaviors than sintered silver under high humidity and H2S exposure, especially with the addition of epoxy resin. However, the corrosion products of sintered copper suffered from a sharp decrease in shear strength after thermal shock tests than sintered silver, which is probably due to the coefficient of thermal expansion mismatch.","Die-attach; Electrochemical analysis; Gas corrosion; Molecular dynamics simulation; Power module packaging; Sintered joint","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:dba1bf53-dc4f-490b-8abc-ecc524e821e1","http://resolver.tudelft.nl/uuid:dba1bf53-dc4f-490b-8abc-ecc524e821e1","Biosynthesis of cyclic ketones by a H2O2 self-sufficient cascade reaction","Wu, Bin (South China University of Technology); Wang, Xiangyun (South China University of Technology); Yang, Bo (South China University of Technology); Ma, Yunjian (South China University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Yonghua (South China University of Technology; Guangdong Youmei Institute of Intelligent Bio-manufacturing Co. Ltd.)","","2023","In the present work we propose a bienzymatic cascade for the oxyfunctionalisation of cycloalkanes to cyclic alcohols/cyclic ketones. By combining a H2O2-dependent peroxygenase with a O2-consuming and H2O2-producing alcohol oxidase an overall aerobic oxidation system was established. A convincing proof-of-concept is presented and some current limitations are outlined.","Alcohol oxidase; Cyclohexanone; HO self-cycling; Unspecific peroxygenase","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:229f9f45-c876-4b78-8243-226f9557f406","http://resolver.tudelft.nl/uuid:229f9f45-c876-4b78-8243-226f9557f406","Water Adsorption in MOFs: Structures and Applications","Zhang, Bo (Tianjin University); Zhu, Zerui (Nanjing Tech University); Wang, Xuerui (Nanjing Tech University); Liu, X. (TU Delft ChemE/Catalysis Engineering; Tianjin University); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering)","","2023","Metal–organic frameworks (MOFs) are superior sorbents for water adsorption-based applications. The unique step-like water isotherm at a MOF-specific relative pressure allows easy loading and regeneration over a small range of temperature and pressure conditions. With good hydrothermal stability and cyclic durability, it stands out over classical sorbents used in applications for humidity control, water harvesting, and adsorption-based heating and cooling. These are easily regenerated at moderate temperatures using “waste” heat or solar heating. The isotherm thermodynamics and adsorption mechanisms are described, and the presence of MOFs in the water–air system is explained. Based on six selection criteria ≈40 reported MOFs and one COF are identified for potential application. Trends and approaches in further synthesis optimization and production scale-up are highlighted. No-MOF-fits-all, each MOF has its own specific step location matching only with a certain application type. Most applications are technically feasible and demonstrated on the bench-scale or small pilot. Their maturity is benchmarked by their technology readiness level. Retrofitting existing applications with MOFs replacing classical desiccants may lead to rapid demonstration. Studies on techno-economic analysis and life cycle analysis are required for a rational evaluation of the feasibility of promising applications.","adsorption desalination; humidity control; MOF formulation; water adsorption isotherm; water harvesting","en","review","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:20817bd2-c257-48d8-8efe-0a55993f3fe0","http://resolver.tudelft.nl/uuid:20817bd2-c257-48d8-8efe-0a55993f3fe0","FedKNOW: Federated Continual Learning with Signature Task Knowledge Integration at Edge","Luopan, Yaxin (Beijing Institute of Technology); Han, Rui (Beijing Institute of Technology); Zhang, Qinglong (Beijing Institute of Technology); Liu, Chi Harold (Beijing Institute of Technology); Wang, Guoren (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Data-Intensive Systems)","","2023","Deep Neural Networks (DNNs) have been ubiquitously adopted in internet of things and are becoming an integral of our daily life. When tackling the evolving learning tasks in real world, such as classifying different types of objects, DNNs face the challenge to continually retrain themselves according to the tasks on different edge devices. Federated continual learning is a promising technique that offers partial solutions but yet to overcome the following difficulties: the significant accuracy loss due to the limited on-device processing, the negative knowledge transfer caused by the limited communication of non-IID data, and the limited scalability on the tasks and edge devices. In this paper, we propose FedKNOW, an accurate and scalable federated continual learning framework, via a novel concept of signature task knowledge. FedKNOW is a client side solution that continuously extracts and integrates the knowledge of signature tasks which are highly influenced by the current task. Each client of FedKNOW is composed of a knowledge extractor, a gradient restorer and, most importantly, a gradient integrator. Upon training for a new task, the gradient integrator ensures the prevention of catastrophic forgetting and mitigation of negative knowledge transfer by effectively combining signature tasks identified from the past local tasks and other clients' current tasks through the global model. We implement FedKNOW in PyTorch and extensively evaluate it against state-of-the-art techniques using popular federated continual learning benchmarks. Extensive evaluation results on heterogeneous edge devices show that FedKNOW improves model accuracy by 63.24% without increasing model training time, reduces communication cost by 34.28%, and achieves more improvements under difficult scenarios such as large numbers of tasks or clients, and training different complex networks.","communication; continual learning; deep neural networks; Federated learning","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-26","","","Data-Intensive Systems","","",""
"uuid:49124128-422f-4f6e-8ef2-45142046fe5d","http://resolver.tudelft.nl/uuid:49124128-422f-4f6e-8ef2-45142046fe5d","EdgeVisionBench: A Benchmark of Evolving Input Domains for Vision Applications at Edge","Zhang, Qinglong (Beijing Institute of Technology); Han, Rui (Beijing Institute of Technology); Liu, Chi Harold (Beijing Institute of Technology); Wang, Guoren (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Data-Intensive Systems)","","2023","Vision applications powered by deep neural networks (DNNs) are widely deployed on edge devices and solve the learning tasks of incoming data streams whose class label and input feature continuously evolve, known as domain shift. Despite its prominent presence in real-world edge scenarios, existing benchmarks used by domain adaptation methods overlook evolving domains and under represent their shifts in label and feature distributions. To address this gap, we present EdgeVisionBench, a benchmark seeking to generate evolving domains of various types and reflect their realistic label and feature shifts encountered by edge-based vision applications. To facilitate evaluating domain adaptation methods on edge devices, we provide an open-source package that automates workload generation, contains popular DNN models and compression techniques, and standardizes evaluations with interactive interfaces. Code and datasets are available at https://github.com/LINC-BIT/EdgeVisionBench.","benchmark; Edge computing; evolving domains; vision applications","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-26","","","Data-Intensive Systems","","",""
"uuid:5d494e33-1adb-4bda-af27-ede0ecd0cc34","http://resolver.tudelft.nl/uuid:5d494e33-1adb-4bda-af27-ede0ecd0cc34","A 1024-Channel 268 nW/pixel 36x36 μm2/ch Data-Compressive Neural Recording IC for High-Bandwidth Brain-Computer Interfaces","Jang, Moon Hyung (Stanford University); Yu, Wei-Han (University of Macau); Lee, Changuk (Yonsei University); Hays, Maddy (Stanford University); Wang, Pingyu (Stanford University); Vitale, Nick (Stanford University); Tandon, Pulkit (Stanford University); Chae, Youngcheol (Yonsei University); Muratore, D.G. (TU Delft Bio-Electronics)","","2023","This paper presents a neural recording IC featuring lossy compression during digitization, thus preventing data deluge and enabling a compact active digital pixel design. The wired-OR-based compression discards unwanted baseline samples while allowing the reconstruction of spike samples. The IC features a 32x32 MEA with 36 μ m pixel pitch and consumes 268nW per pixel from a single 1V supply. It achieves 9.8 μ VRMS input-referred noise and 0.3-5kHz bandwidth, resulting in NEF/PEF of 3.7/14.1.","brain; compression; interface; neural; recording","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-24","","","Bio-Electronics","","",""
"uuid:1b72b2c7-c148-48be-b019-c03935d3f7f1","http://resolver.tudelft.nl/uuid:1b72b2c7-c148-48be-b019-c03935d3f7f1","Particle fusion of super-resolution data reveals the unit structure of Nup96 in Nuclear Pore Complex","Wang, W. (TU Delft ImPhys/Computational Imaging); Jakobi, A. (TU Delft BN/Arjen Jakobi Lab); Wu, Yu-Le (European Molecular Biology Laboratory Heidelberg); Ries, Jonas (University of Vienna); Stallinga, S. (TU Delft ImPhys/Imaging Physics); Rieger, B. (TU Delft ImPhys/Computational Imaging; TU Delft ImPhys/Rieger group)","","2023","Single molecule localization microscopy offers resolution nearly down to the molecular level with specific molecular labelling, and is thereby a promising tool for structural biology. In practice, however, the actual value to this field is limited primarily by incomplete fluorescent labelling of the structure. This missing information can be completed by merging information from many structurally identical particles in a particle fusion approach similar to cryo-EM single-particle analysis. In this paper, we present a data analysis of particle fusion results of fluorescently labelled Nup96 nucleoporins in the Nuclear Pore Complex to show that Nup96 occurs in a spatial arrangement of two rings of 8 units with two Nup96 copies per unit giving a total of 32 Nup96 copies per pore. We use Artificial Intelligence assisted modeling in Alphafold to extend the existing cryo-EM model of Nup96 to accurately pinpoint the positions of the fluorescent labels and show the accuracy of the match between fluorescent and cryo-EM data to be better than 3 nm in-plane and 5 nm out-of-plane.","","en","journal article","","","","","","","","","","ImPhys/Imaging Physics","ImPhys/Computational Imaging","","",""
"uuid:4e519d5e-7c11-4908-8f76-b1d4faeeae10","http://resolver.tudelft.nl/uuid:4e519d5e-7c11-4908-8f76-b1d4faeeae10","Triplet correlations in Cooper pair splitters realized in a two-dimensional electron gas","Wang, Q. (TU Delft QRD/Goswami Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); ten Haaf, S.L.D. (TU Delft QRD/Goswami Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Kulesh, I. (TU Delft QRD/Goswami Lab; TU Delft QuTech Advanced Research Centre); Xiao, Di (Purdue University); Thomas, Candice (Purdue University); Manfra, Michael J. (Purdue University; Microsoft); Goswami, S. (TU Delft QRD/Goswami Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)","","2023","Cooper pairs occupy the ground state of superconductors and are typically composed of maximally entangled electrons with opposite spin. In order to study the spin and entanglement properties of these electrons, one must separate them spatially via a process known as Cooper pair splitting (CPS). Here we provide the first demonstration of CPS in a semiconductor two-dimensional electron gas (2DEG). By coupling two quantum dots to a superconductor-semiconductor hybrid region we achieve efficient Cooper pair splitting, and clearly distinguish it from other local and non-local processes. When the spin degeneracy of the dots is lifted, they can be operated as spin-filters to obtain information about the spin of the electrons forming the Cooper pair. Not only do we observe a near perfect splitting of Cooper pairs into opposite-spin electrons (i.e. conventional singlet pairing), but also into equal-spin electrons, thus achieving triplet correlations between the quantum dots. Importantly, the exceptionally large spin-orbit interaction in our 2DEGs results in a strong triplet component, comparable in amplitude to the singlet pairing. The demonstration of CPS in a scalable and flexible platform provides a credible route to study on-chip entanglement and topological superconductivity in the form of artificial Kitaev chains.","","en","journal article","","","","","","","","","","","QRD/Goswami Lab","","",""
"uuid:b9025aad-e658-4879-ae06-c146059b33fe","http://resolver.tudelft.nl/uuid:b9025aad-e658-4879-ae06-c146059b33fe","The FluidFlower Validation Benchmark Study for the Storage of CO 2","Flemisch, Bernd (University of Stuttgart); Nordbotten, Jan M. (University of Bergen; Norwegian Research Center); Geiger, S. (TU Delft Applied Geology; Heriot-Watt University); Hajibeygi, H. (TU Delft Reservoir Engineering); Tian, X. (TU Delft Reservoir Engineering); Voskov, D.V. (TU Delft Reservoir Engineering); Wang, Y. (TU Delft Numerical Analysis); Wapperom, M.B. (TU Delft Reservoir Engineering); Zhang, Z. (TU Delft Numerical Analysis)","","2023","Successful deployment of geological carbon storage (GCS) requires an extensive use of reservoir simulators for screening, ranking and optimization of storage sites. However, the time scales of GCS are such that no sufficient long-term data is available yet to validate the simulators against. As a consequence, there is currently no solid basis for assessing the quality with which the dynamics of large-scale GCS operations can be forecasted. To meet this knowledge gap, we have conducted a major GCS validation benchmark study. To achieve reasonable time scales, a laboratory-size geological storage formation was constructed (the “FluidFlower”), forming the basis for both the experimental and computational work. A validation experiment consisting of repeated GCS operations was conducted in the FluidFlower, providing what we define as the true physical dynamics for this system. Nine different research groups from around the world provided forecasts, both individually and collaboratively, based on a detailed physical and petrophysical characterization of the FluidFlower sands. The major contribution of this paper is a report and discussion of the results of the validation benchmark study, complemented by a description of the benchmarking process and the participating computational models. The forecasts from the participating groups are compared to each other and to the experimental data by means of various indicative qualitative and quantitative measures. By this, we provide a detailed assessment of the capabilities of reservoir simulators and their users to capture both the injection and post-injection dynamics of the GCS operations.","Geological carbon storage; Model intercomparison; Validation benchmark; Validation experiment","en","journal article","","","","","","","","","","","Applied Geology","","",""
"uuid:e0c7f043-631e-4add-af40-34877c89396b","http://resolver.tudelft.nl/uuid:e0c7f043-631e-4add-af40-34877c89396b","Rapid Fabrication of High-Performance Flexible Pressure Sensors Using Laser Pyrolysis Direct Writing","Wang, S. (TU Delft Bio-Electronics; Southern University of Science and Technology); Zong, Qihang (Southern University of Science and Technology); Yang, Huiru (Southern University of Science and Technology); Tan, C. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology); Huang, Qianming (Southern University of Science and Technology); Liu, X. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); French, P.J. (TU Delft Bio-Electronics); Ye, H. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology)","","2023","The fabrication of flexible pressure sensors with low cost, high scalability, and easy fabrication is an essential driving force in developing flexible electronics, especially for high-performance sensors that require precise surface microstructures. However, optimizing complex fabrication processes and expensive microfabrication methods remains a significant challenge. In this study, we introduce a laser pyrolysis direct writing technology that enables rapid and efficient fabrication of high-performance flexible pressure sensors with a micro-truncated pyramid array. The pressure sensor demonstrates exceptional sensitivities, with the values of 3132.0, 322.5, and 27.8 kPa-1 in the pressure ranges of 0-0.5, 0.5-3.5, and 3.5-10 kPa, respectively. Furthermore, the sensor exhibits rapid response times (loading: 22 ms, unloading: 18 ms) and exceptional reliability, enduring over 3000 pressure loading and unloading cycles. Moreover, the pressure sensor can be easily integrated into a sensor array for spatial pressure distribution detection. The laser pyrolysis direct writing technology introduced in this study presents a highly efficient and promising approach to designing and fabricating high-performance flexible pressure sensors utilizing micro-structured polymer substrates.","continuous laser pyrolysis; flexible pressure sensor; laser direct writing; micro-truncated pyramid; PDMS; UV laser","en","journal article","","","","","","","","","","","Bio-Electronics","","",""
"uuid:3dd9647a-22d7-4589-87a5-fd7c9cbfce4f","http://resolver.tudelft.nl/uuid:3dd9647a-22d7-4589-87a5-fd7c9cbfce4f","Simulation, Prediction, and Verification of the Corrosion Behavior of Cu-Ag Composite Sintered Paste for Power Semiconductor Die-attach Applications","Wang, Xinyue (Fudan University); Yang, Zhoudong (Fudan University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Zhang, Jing (Heraeus Materials Technology Shanghai Ltd.); Liu, Pan (Fudan University)","","2023","With the popularization of wide band-gap power modules in offshore wind power systems and water surface photovoltaic power stations, packaging materials face challenges of corrosion by salt, blended with high humidity. Copper-silver (Cu-Ag) composite sintered paste was proposed by researchers as a novel die-attach material for a lower cost and anti-electro migration ability. However, the potential difference between copper and silver forms galvanic corrosion in a high-humidity environment, resulting in accelerated failure combined with salt mist. To further promote the application of composite sintered materials, a copper-silver double-sphere galvanic corrosion model based on finite element simulation was proposed in this paper. The relationship between corrosion rate and time of different Cu-Ag particle size combinations under different sintering degrees was predicted by initial exchange current density. Through the electrochemical characterization of the sintered samples, the optimal combination of materials was further discussed. The accuracy of the model was also verified. The conclusions obtained from both the experiments and simulation work provide guidance for future anti-corrosion analysis, as well as the reliability improvement of novel composite sintered materials.","die-attach material; FEM simulation; galvanic corrosion; power electronic packaging","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-30","","","Electronic Components, Technology and Materials","","",""
"uuid:44f83d7c-20bd-4ba3-bdda-f3f95ca10d90","http://resolver.tudelft.nl/uuid:44f83d7c-20bd-4ba3-bdda-f3f95ca10d90","PIVODL: Privacy-Preserving Vertical Federated Learning Over Distributed Labels","Zhu, Hangyu (University of Surrey); Wang, R. (TU Delft Cyber Security); Jin, Yaochu (Bielefeld University; University of Surrey); Liang, K. (TU Delft Cyber Security)","","2023","Federated learning (FL) is an emerging privacy preserving machine learning protocol that allows multiple devices to collaboratively train a shared global model without revealing their private local data. Nonparametric models like gradient boosting decision trees (GBDTs) have been commonly used in FL for vertically partitioned data. However, all these studies assume that all the data labels are stored on only one client, which may be unrealistic for real-world applications. Therefore, in this article, we propose a secure vertical FL framework, named privacy-preserving vertical federated learning system over distributed labels (PIVODL), to train GBDTs with data labels distributed on multiple devices. Both homomorphic encryption and differential privacy are adopted to prevent label information from being leaked through transmitted gradients and leaf values. Our experimental results show that both information leakage and model performance degradation of the proposed PIVODL are negligible. Impact Statement - Federated learning is a distributed machine learning framework proposed for privacy preservation. Most federated learning algorithms work on horizontally partitioned data, with only a few exceptions considering vertically partitioned data that is widely seen in the real world. However, existing vertical federated learning makes an unrealistic assumption that data labels are distributed on only one device and no research has been reported so far that considers data labels distributed on multiple client devices. The PIVODL framework reported in this article allows us to build a secure vertical federated XGBoost system, in which the labels may distributed either on one device or on multiple devices, making it possible to apply federated learning to a wider range of real-world problems.","Encryption; gradient boosting decision tree (GBDT); privacy preservation; vertical federated learning (VFL)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-03-22","","","Cyber Security","","",""
"uuid:3e54aaa0-46f8-4411-a5ca-351a314d73ce","http://resolver.tudelft.nl/uuid:3e54aaa0-46f8-4411-a5ca-351a314d73ce","The Multimodal Information Based Speech Processing (Misp) 2022 Challenge: Audio-Visual Diarization And Recognition","Wang, Zhe (University of Science and Technology of China); Wu, Shilong (University of Science and Technology of China); Chen, Hang (University of Science and Technology of China); He, Mao-Kui (University of Science and Technology of China); Du, Jun (University of Science and Technology of China); Lee, Chin-Hui (Georgia Institute of Technology); Chen, Jingdong (Northwestern Polytechnical University); Watanabe, Shinji (Carnegie Mellon University); Siniscalchi, Sabato Marco (Georgia Institute of Technology; University of Enna Kore); Scharenborg, O.E. (TU Delft Multimedia Computing); Liu, Diyuan (iFlytek)","","2023","The Multi-modal Information based Speech Processing (MISP) challenge aims to extend the application of signal processing technology in specific scenarios by promoting the research into wake-up words, speaker diarization, speech recognition, and other technologies. The MISP2022 challenge has two tracks: 1) audio-visual speaker diarization (AVSD), aiming to solve ""who spoken when"" using both audio and visual data; 2) a novel audio-visual diarization and recognition (AVDR) task that focuses on addressing ""who spoken what when"" with audio-visual speaker diarization results. Both tracks focus on the Chinese language, and use far-field audio and video in real home-tv scenarios: 2-6 people communicating each other with TV noise in the background. This paper introduces the dataset, track settings, and baselines of the MISP2022 challenge. Our analyses of experiments and examples indicate the good performance of AVDR baseline system, and the potential difficulties in this challenge due to, e.g., the far-field video quality, the presence of TV noise in the background, and the indistinguishable speakers.","MISP challenge; speaker diarization; speech recognition; multimodality","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-05","","","Multimedia Computing","","",""
"uuid:b2f7db77-5ab3-4681-a89d-599fa216d1cd","http://resolver.tudelft.nl/uuid:b2f7db77-5ab3-4681-a89d-599fa216d1cd","Learning-based NLOS Detection and Uncertainty Prediction of GNSS Observations with Transformer-Enhanced LSTM Network","Zhang, Haoming (Rheinisch-Westfälische Technische Hochschule); Wang, Zhanxin (Rheinisch-Westfälische Technische Hochschule); Vallery, H. (TU Delft Biomechatronics & Human-Machine Control; Rheinisch-Westfälische Technische Hochschule)","","2023","The global navigation satellite systems (GNSS) play a vital role in transport systems for accurate and consistent vehicle localization. However, GNSS observations can be distorted due to multipath effects and non-line-of-sight (NLOS) receptions in challenging environments such as urban canyons. In such cases, traditional methods to classify and exclude faulty GNSS observations may fail, leading to unreliable state estimation and unsafe system operations. This work proposes a deep-learning-based method to detect NLOS receptions and predict GNSS pseudorange errors by analyzing GNSS observations as a spatio-temporal modeling problem. Compared to previous works, we construct a transformer-like attention mechanism to enhance the long short-term memory (LSTM) networks, improving model performance and generalization. For the training and evaluation of the proposed network, we used labeled datasets from the cities of Hong Kong and Aachen. We also introduce a dataset generation process to label the GNSS observations using lidar maps. In experimental studies, we compare the proposed network with a deep-learning-based model and classical machine-learning models. Furthermore, we conduct ablation studies of our network components and integrate the NLOS detection with data out-of-distribution in a state estimator. As a result, our network presents improved precision and recall ratios compared to other models. Additionally, we show that the proposed method avoids trajectory divergence in real-world vehicle localization by classifying and excluding NLOS observations.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-08-13","","","Biomechatronics & Human-Machine Control","","",""
"uuid:d2d0fa44-c7be-48ca-a777-2e6754acc25e","http://resolver.tudelft.nl/uuid:d2d0fa44-c7be-48ca-a777-2e6754acc25e","Screen Perturbation: Adversarial Attack and Defense on Under-Screen Camera","Ye, Hanting (TU Delft Embedded Systems); Lan, G. (TU Delft Embedded Systems); Jia, Jinyuan (The Pennsylvania State University); Wang, Q. (TU Delft Embedded Systems)","","2023","Smartphones are moving towards the fullscreen design for better user experience. This trend forces front cameras to be placed under screen, leading to Under-Screen Cameras (USC). Accordingly, a small area of the screen is made translucent to allow light to reach the USC. In this paper, we utilize the translucent screen's features to inconspicuously modify its pixels, imperceptible to human eyes but inducing perturbations on USC images. These screen perturbations affect deep learning models in image classification and face recognition. They can be employed to protect user privacy, or disrupt the front camera's functionality in the malicious case. We design two methods, one-pixel perturbation and multiple-pixel perturbation, that can add screen perturbations to images captured by USC and successfully fool various deep learning models. Our evaluations, with three commercial full-screen smartphones on testbed datasets and synthesized datasets, show that screen perturbations significantly decrease the average image classification accuracy, dropping from 85% to only 14% for one-pixel perturbation and 5.5% for multiple-pixel perturbation. For face recognition, the average accuracy drops from 91% to merely 1.8% and 0.25%, respectively.","Under-screen camera; adversarial perturbation; privacy","en","book chapter","Association for Computing Machinery (ACM)","","","","","","","","","","Embedded Systems","","",""
"uuid:e1f2752d-63be-4109-8121-584c2a68632d","http://resolver.tudelft.nl/uuid:e1f2752d-63be-4109-8121-584c2a68632d","Bracelet+: Harvesting the Leaked RF Energy in VLC with Wearable Bracelet Antenna","Cui, Minhao (University of Massachusetts Amherst); Wang, Q. (TU Delft Embedded Systems); Xiong, Jie (University of Massachusetts Amherst)","","2023","Visible Light Communication (VLC) is widely considered a promising technology for the coming 6G networks. Recent studies show that a VLC transmitter not only emits visible light signals but also leaks RF signals during the transmission. In this work, we devote effort to harvesting the free leaked RF energy from VLC transmissions. We observe that the surrounding objects could help a coil antenna harvest significantly more RF energy. Based on this observation, we propose our system Bracelet+, which involves the human body in the harvesting system to increase the harvested power. After careful analysis of the influence of the human body on the harvested power, we prototype the coil antenna as a bracelet that achieves both high harvested power and convenience for wearing. The average power of the RF energy harvested by our design is 10 larger than that of the conventional coil antenna, without causing any interference to the communication of VLC systems. The harvested power can reach up to micro-watts in our tested scenarios. Such a micro-watt level of harvested energy has the potential to power up ultra-low-power sensors such as temperature sensors and glucose sensors.","RF leakage; energy harvesting; human body-augmented; side channel; visible light communication","en","conference paper","Association for Computing Machinery (ACM)","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-24","","","Embedded Systems","","",""
"uuid:ea1ac20e-5081-4e2d-bbb4-ddf7055c4a7f","http://resolver.tudelft.nl/uuid:ea1ac20e-5081-4e2d-bbb4-ddf7055c4a7f","HueSense: Featuring LED Lights Through Hue Sensing","Singh, Jagdeep (Toshiba Europe Ltd); Wang, Q. (TU Delft Embedded Systems); Zuniga, Marco (TU Delft Networked Systems); Farnham, Tim (Toshiba Europe Ltd)","","2023","Visible Light Positioning (VLP) has been prevalent in providing high-precision localization systems in the past decade. However, the commercial availability or usage is still limited primarily due to the requirement of changing the existing lighting infrastructure. In this paper, we propose HueSense, an alternative technique to develop a passive VLP system by extracting light-emission intrinsic features, such as dominant colours present in the white LED light. The method can eliminate the need to change lighting-infrastructure, and only uses cheaper and power-efficient off-the-shelf hue sensors. Our experiments demonstrate that HueSense can achieve a location-mapping accuracy of 80.14% with a moving robot in uncontrolled lighting environments.","passive visible light positioning; colour sensors","en","conference paper","Association for Computing Machinery (ACM)","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-08-13","","","Embedded Systems","","",""
"uuid:5b9709a2-4a02-4793-b6a3-64fe6c762daf","http://resolver.tudelft.nl/uuid:5b9709a2-4a02-4793-b6a3-64fe6c762daf","A bio-inspired and switchable H+/OH− ion-channel for room temperature exhaled CO2 chemiresistive sensing","Chen, Honghao (South China Normal University); Lu, Ruofei (South China Normal University); Gao, Yixun (South China Normal University); Yue, Xiaorui (South China Normal University); Yang, Haihong (The First Affiliated Hospital of Guangzhou Medical University); Li, Hao (South China Normal University); Lee, Yi Kuen (The Hong Kong University of Science and Technology); French, P.J. (TU Delft Bio-Electronics); Wang, Yao (South China Normal University); Zhou, Guofu (South China Normal University)","","2023","Inspired by the CO2-induced reversible activation mechanism of the slow anion channel 1 (SLAC1) in plant stomatal guard cells during plant photosynthesis, we designed and prepared a CO2- switchable H+/OH− ion channel (CSPH ion channel). A high-performance chemiresistive room temperature CO2 sensor has been prepared based on this CSPH ion channel. The obtained CO2 room temperature sensor γ-CD-MOF@RhB exhibits high sensitivity (Rg/R0 = 1.50, 100 ppm), excellent selectivity, good stability (less than 5% reduction in 30 days response value), and 99.96% consistency with commercial infrared CO2 meter. The practical limit of detection (pLOD) of the γ-CD-MOF@RhB sensor reaches 10 ppm at room temperature toward CO2, which is the lowest for reported MOF-derived chemiresistive room temperature CO2 sensors so far. Ion conduction mechanism studies have shown that the CSPH ion channel behaves as a CO2-switchable H+/OH− ion channel with a switching point of approximately 60 000 ppm CO2. As an application attempt, the fabricated low pLOD CO2 sensor has been used for human exhaled CO2 detection to compare CO2 concentration in the breath of individuals before and after exercise and COVID-19. It was also logically indicated that the average concentration of human exhaled CO2 after COVID-19 recovery is different for undiseased subjects.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-03-25","","","Bio-Electronics","","",""
"uuid:d3965460-66ef-4df8-b5c5-7d9a020249c0","http://resolver.tudelft.nl/uuid:d3965460-66ef-4df8-b5c5-7d9a020249c0","Community Detection for Temporal Weighted Bipartite Networks","Fernández Robledo, O. (TU Delft Multimedia Computing); Klepper, M. (Koninklijke KPN); van Boven, E.F.M. (TU Delft Network Architectures and Services; Koninklijke KPN); Wang, H. (TU Delft Multimedia Computing)","Cherifi, Hocine (editor); Mantegna, Rosario Nunzio (editor); Rocha, Luis M. (editor); Cherifi, Chantal (editor); Micciche, Salvatore (editor)","2023","Community detection of temporal (time-evolving) bipartite networks is challenging because it can be performed either on the temporal bipartite network, or on various projected networks, composed of only one type of nodes, via diverse community detection algorithms. In this paper, we aim to systematically design detection methods addressing both network choices and community detection algorithms, and to compare the community structures detected by different methods. We illustrate our methodology by using a telecommunications network as an example. We find that three methods proposed identify evident community structures: one is performed on each snapshot of the temporal network, and the other two, in temporal projections. We characterise the community structures detected by each method by an evaluation network in which the nodes are the services of the telecommunications network, and the weight of the links between them are the number of snapshots that both services were assigned to the same community. Analysing the evaluation networks of the three methods reveals the similarity and difference among these methods in identifying common node pairs or groups of nodes that often belong to the same community. We find that the two methods that are based on the same projected network identify consistent community structures, whereas the method based on the original temporal bipartite network complements this vision of the community structure. Moreover, we found a non-trivial number of node pairs that belong consistently to the same community in all the methods applied.","Bipartite networks; Community detection; Temporal networks","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-26","","","Multimedia Computing","","",""
"uuid:266ac5de-2ed6-46ff-b751-267f1fae97d1","http://resolver.tudelft.nl/uuid:266ac5de-2ed6-46ff-b751-267f1fae97d1","Drug Trafficking in Relation to Global Shipping Network","Leibbrandt, Louise (Student TU Delft); Zhang, S. (TU Delft Multimedia Computing); Roelvink, M.A.T. (TU Delft Support Delft Institute of Applied Mathematics); Bergkamp, Stan (Student TU Delft); Li, Xinqi (Student TU Delft); Bisschop, Lieselot (Erasmus Universiteit Rotterdam); Wingerde, Karin van (Erasmus Universiteit Rotterdam); Wang, H. (TU Delft Multimedia Computing)","Cherifi, Hocine (editor); Mantegna, Rosario Nunzio (editor); Rocha, Luis M. (editor); Cherifi, Chantal (editor); Micciche, Salvatore (editor)","2023","This paper aims to understand to what extent the amount of drug (e.g., cocaine) trafficking per country can be explained and predicted using the global shipping network. We propose three distinct network approaches, based on topological centrality metrics, Susceptible-Infected-Susceptible spreading process and a flow optimization model of drug trafficking on the shipping network, respectively. These approaches derive centrality metrics, infection probability, and inflow of drug traffic per country respectively, to estimate the amount of drug trafficking. We use the amount of drug seizure as an approximation of the amount of drug trafficking per country to evaluate our methods. Specifically, we investigate to what extent different methods could predict the ranking of countries in drug seizure (amount). Furthermore, these three approaches are integrated by a linear regression method in which we combine the nodal properties derived by each method to build a comprehensive model for the cocaine seizure data. Our analysis finds that the unweighted eigenvector centrality metric combined with the inflow derived by the flow optimization method best identifies the countries with a large amount of drug seizure (e.g., rank correlation 0.45 with the drug seizure). Extending this regression model with two extra features, the distance of a country from the source of cocaine production and a country’s income group, increases further the prediction quality (e.g., rank correlation 0.79). This final model provides insights into network derived properties and complementary country features that are explanatory for the amount of cocaine seized. The model can also be used to identify countries that have no drug seizure data but are possibly susceptible to cocaine trafficking.","Drug seizure; Drug trafficking; Network method; Shipping network","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-26","","","Multimedia Computing","","",""
"uuid:59e43f99-3582-4779-bbee-ddffad4c56aa","http://resolver.tudelft.nl/uuid:59e43f99-3582-4779-bbee-ddffad4c56aa","Memory Based Temporal Network Prediction","Zou, L. (TU Delft Multimedia Computing); Wang, An (University of Warwick); Wang, H. (TU Delft Multimedia Computing)","Cherifi, Hocine (editor); Mantegna, Rosario Nunzio (editor); Rocha, Luis M. (editor); Cherifi, Chantal (editor); Micciche, Salvatore (editor)","2023","Temporal networks are networks like physical contact networks whose topology changes over time. Predicting future temporal network is crucial e.g., to forecast and mitigate the spread of epidemics and misinformation on the network. Most existing methods for temporal network prediction are based on machine learning algorithms, at the expense of high computational costs and limited interpretation of the underlying mechanisms that form the networks. This motivates us to develop network-based models to predict the temporal network at the next time step based on the network observed in the past. Firstly, we investigate temporal network properties to motivate our network prediction models and to explain how the performance of these models depends on the temporal networks. We explore the similarity between the network topology (snapshot) at any two time steps with a given time lag/interval. We find that the similarity is relatively high when the time lag is small and decreases as the time lag increases. Inspired by such time-decaying memory of temporal networks and recent advances, we propose two models that predict a link’s future activity (i.e., connected or not), based on the past activities of the link itself or also of neighboring links, respectively. Via seven real-world physical contact networks, we find that our models outperform in both prediction quality and computational complexity, and predict better in networks that have a stronger memory. Beyond, our model also reveals how different types of neighboring links contribute to the prediction of a given link’s future activity, again depending on properties of temporal networks.","Network-Based prediction; Temporal network prediction; Temporal network property","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-08-28","","","Multimedia Computing","","",""
"uuid:51a2d05c-c035-452c-8676-55c2aa0549f0","http://resolver.tudelft.nl/uuid:51a2d05c-c035-452c-8676-55c2aa0549f0","A GNN-Based Architecture for Group Detection from Spatio-Temporal Trajectory Data","Nasri, Maedeh (Universiteit Leiden); Fang, Zhizhou (Universiteit Leiden); Baratchi, Mitra (Universiteit Leiden); Englebienne, Gwenn (University of Twente); Wang, Shenghui (University of Twente); Koutamanis, A. (TU Delft Design & Construction Management); Rieffe, Carolien (Universiteit Leiden; University of Twente; University College London (UCL))","Crémilleux, Bruno (editor); Hess, Sibylle (editor); Nijssen, Siegfried (editor)","2023","Detecting and analyzing group behavior from spatio-temporal trajectories is an interesting topic in various domains, such as autonomous driving, urban computing, and social sciences. This paper revisits the group detection problem from spatio-temporal trajectories and proposes “WavenetNRI”, a graph neural network (GNN) based method. The proposed WavenetNRI extends the previously proposed neural relational inference (NRI) method (an unsupervised learning approach for inferring interactions from observational data) in two directions: (1) symmetric edge features and edge updating processes are applied to generate symmetric edge representations corresponding to the symmetric binary group relationships; (2) a gated dilated residual causal convolutional (GD-RCC) block is adopted to capture both short and long dependency of the edge feature sequences. We evaluated the performance of the proposed model on three simulation datasets and three real-world pedestrian datasets, using the Group Mitre metric to measure the quality of the predicted groups. We compared WavenetNRI with four baseline methods, including two clustering-based and two classification-based methods. In these experiments, NRI and WavenetNRI outperformed all other baselines on the group-interaction simulation datasets, while NRI performed slightly better than WavenetNRI. On the pedestrian datasets, the WavenetNRI outperformed other classification-based baselines. However, it did not compete against the clustering-based methods. Our ablation study showed that while both proposed changes cannot be effective at the same time, either of them can improve the performance of the original NRI on one dataset type.","Deep learning; Group detection; Spatio-temporal data","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care. Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-01","","","Design & Construction Management","","",""
"uuid:4d9c413c-0086-4dc0-8d9d-060d2a1e4931","http://resolver.tudelft.nl/uuid:4d9c413c-0086-4dc0-8d9d-060d2a1e4931","Bituminous Binder and Bituminous Mixture Modified with Waste Polyethylene","Tušar, M. (Slovenian National Building and Civil Engineering Institute); Poulikakos, L. D. (Swiss Federal Laboratories for Materials Science and Technology (Empa)); Kakar, M. R. (Bern University of Applied Sciences); Pasquini, E. (Università degli Studi di Padova); Pasetto, M. (Università degli Studi di Padova); Porot, L. (Kraton Chemical B.V.); Wang, D. (Aalto University); Varveri, Aikaterini (TU Delft Pavement Engineering); Jing, R. (TU Delft Pavement Engineering)","Cannone Falchetto, Augusto (editor); Poulikakos, Lily (editor); Pasquini, Emiliano (editor); Wang, Di (editor)","2023","RILEM TC-279 WMR task group TG 1 studied the performance of waste Polyethylene (PE) in bituminous binders and bituminous mixtures. Several laboratories participated in this study following a common protocol. Locally sources aggregates and bituminous binder and same source of waste PE were utilized. The binder experiments showed that at high temperatures, using MSCR tests, PE modified blends had better resistance to permanent deformation in comparison to the non modified binder. Whereas at intermediate temperatures, using the LAS tests, fatigue performance of the PE blends could withstand more loading cycles under low strains; however, it could sustain less loading cycles under high strains due to the increase in brittleness. Dry process was used for the mixture experiments in order to bypass the stability and inhomogeneity experience that was observed at the binder scale. The PE modified mixtures showed improved workability and increased strength. The higher the PE dosage, the higher the ITS increase with respect to the values measured for the control materials (i.e., without any plastic waste) thanks to the improved cohesion of the plastic modified mastic. The stiffness experiments tended to show an improved performance with a lower time dependence and a higher elasticity when plastic was added. The cyclic compression tests demonstrated a reduced creep rate along with a higher creep modulus thanks to the addition of PE; similar conclusions can be drawn from the experimental findings coming from wheel tracking test. Furthermore, acceptable and often improved moisture resistance was observed for PE modified materials.","Asphalt; Binder; Bituminous mixture; Polyethylene; Waste","en","book chapter","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-01","","","Pavement Engineering","","",""
"uuid:e6245999-4884-497d-a53d-5b7294b64cc6","http://resolver.tudelft.nl/uuid:e6245999-4884-497d-a53d-5b7294b64cc6","Formation Control of Skid-Steered Vehicles Based on Distributed Model Predictive Control","Wang, Yiping (Beijing Institute of Technology); Li, Xueyuan (Beijing Institute of Technology); Liu, Qi (Beijing Institute of Technology); Li, Songhao (Beijing Institute of Technology); Luan, Tian (Beijing Institute of Technology); Li, Z. (TU Delft Transport and Planning; Beijing Institute of Technology)","Fu, Wenxing (editor); Gu, Mancang (editor); Niu, Yifeng (editor)","2023","The skid-steered vehicle has the advantages of simple structure and strong maneuverability. Its formation driving can effectively improve safety, reduce energy consumption and exert its benefits, and has wide application prospects in military and civilian fields. Differential skid steering has strong horizontal and vertical coupling characteristics, so the tracking performance of the vehicle is poor. Therefore, it is of great significance to study horizontal and vertical joint control. Firstly, the mathematical model of the vehicle platoon is established to realize the formation control of skid-steered vehicles. Then, a combined horizontal and vertical control strategy for skid-steered vehicle formation is proposed, and a distributed model predictive controller is designed. Finally, simulation experiments verified that the designed method has good feasibility and stability.","Distributed model predictive control; Formation driving; Lateral and longitudinal control; Skid-steered vehicle","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-10","","","Transport and Planning","","",""
"uuid:25f83678-f36b-48e4-8a06-afaeabf5670d","http://resolver.tudelft.nl/uuid:25f83678-f36b-48e4-8a06-afaeabf5670d","Robustness of Network Controllability with Respect to Node Removals","Wang, F. (TU Delft Network Architectures and Services); Kooij, Robert (DIANA FEA)","Cherifi, Hocine (editor); Mantegna, Rosario Nunzio (editor); Rocha, Luis M. (editor); Cherifi, Chantal (editor); Micciche, Salvatore (editor)","2023","Network controllability and its robustness has been widely studied. However, analytical methods to calculate network controllability with respect to node removals are currently lacking. This paper develops methods, based upon generating functions for the in- and out-degree distributions, to approximate the minimum number of driver nodes needed to control directed networks, during random and targeted node removals. By validating the proposed methods on synthetic and real-world networks, we show that our methods work very well in the case of random node removals and reasonably well in the case of targeted node removals, in particular for moderate fractions of attacked nodes.","Complex networks; Controllability; Node attacks; Node failures","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-26","","","Network Architectures and Services","","",""
"uuid:4ef8308f-ca44-4701-8253-87790026ce90","http://resolver.tudelft.nl/uuid:4ef8308f-ca44-4701-8253-87790026ce90","Photogrammetric Reconstruction of a Stolen Statue","Liu, Z. (TU Delft Emerging Materials; Centre for Perceptual and Interactive Intelligence Limited, Hong Kong); Doubrovski, E.L. (TU Delft Mechatronic Design); Geraedts, Jo M.P. (TU Delft Emerging Materials); Yam, Y (Centre for Perceptual and Interactive Intelligence Limited, Hong Kong); Wang, W. (The Chinese University of Hong Kong; Centre for Perceptual and Interactive Intelligence Limited, Hong Kong); Wang, C.C.L. (The University of Manchester)","Babaei, V. (editor); Skouras, M. (editor)","2023","In this paper, we propose a method to reconstruct a digital 3D model of a stolen/damaged statue using photogrammetric methods. This task is challenging because the number of available photos for a stolen statue is in general very limited – especially the side/back view photos. Besides using standard structure-from-motion and multi-view stereo methods, we match image pairs with low overlap using sliding windows and maximize the normalized cross-correlation (NCC) based patch-consistency so that the image pairs can be well aligned into a complete model to build the 3D mesh surface. Our method is based on the prior of the planar side on the statue’s pedestal, which can cover a large range of statues. We hope this work will motivate more research efforts for the reconstruction of those stolen/damaged statues and heritage preservation.","Computing methodologies; Reconstruction; Mesh models","en","conference paper","","","","","","","","","","","Mechatronic Design","","",""
"uuid:31864b30-7708-4aec-8ef8-17814c10b38f","http://resolver.tudelft.nl/uuid:31864b30-7708-4aec-8ef8-17814c10b38f","Synchronization of power systems under stochastic disturbances","Wang, Zhen (Shandong University); Xi, Kaihua (Shandong University); Cheng, Aijie (Shandong University); Lin, H.X. (TU Delft Mathematical Physics; Universiteit Leiden); Ran, André C.M. (Vrije Universiteit Amsterdam; North-West University); van Schuppen, J.H. (TU Delft Mathematical Physics); Zhang, Chenghui (Shandong University)","","2023","The synchronization of power generators is an important condition for the proper functioning of a power system, in which the fluctuations in frequency and the phase angle differences between the generators are sufficiently small when subjected to stochastic disturbances. Serious fluctuations can prompt desynchronization, which may lead to widespread power outages. Here, we model the stochastic disturbance by a Brownian motion process in the linearized system of the non-linear power systems and characterize the fluctuations by the variances of the frequency and the phase angle differences in the invariant probability distribution. We propose a method to calculate the variances of the frequency and the phase angle differences. For the system with uniform disturbance-damping ratio, we derive explicit formulas for the variance matrices of the frequency and the phase angle differences. It is shown that the fluctuation of the frequency at a node depends on the disturbance-damping ratio and the inertia at this node only, and the fluctuations of the phase angle differences in the lines are independent of the inertia. In particular, the synchronization stability is related to the cycle space of the network. We reveal the influences of constructing new lines and increasing capacities of lines on the fluctuations in the phase angle differences in the existing lines. The results are illustrated for the transmission system of Shandong Province of China. For the system with non-uniform disturbance-damping ratio, we further obtain bounds of the variance matrices.","Invariant probability distribution; Variances; Network topology; Graph theory; System stability; Cycle space","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-08-21","","","Mathematical Physics","","",""
"uuid:9f0f6515-da60-4120-a376-cc98534b0a43","http://resolver.tudelft.nl/uuid:9f0f6515-da60-4120-a376-cc98534b0a43","Quantum states and intertwining phases in kagome materials","Wang, Y. (TU Delft QN/Ali Lab; Kavli institute of nanoscience Delft); Wu, H. (TU Delft QN/Ali Lab; Kavli institute of nanoscience Delft); McCandless, Gregory T. (Baylor University); Chan, Julia Y. (Baylor University); Ali, M.N. (TU Delft QN/Ali Lab; Kavli institute of nanoscience Delft)","","2023","In solid materials, non-trivial topological states, electron correlations and magnetism are central ingredients for realizing quantum properties, including unconventional superconductivity, charge and spin density waves and quantum spin liquids. The kagome lattice, made up of corner-sharing triangles, can host these three ingredients simultaneously and has proved to be a fertile platform for studying diverse quantum phenomena including those stemming from the interplay of these ingredients. This Review introduces the fundamental properties of the kagome lattice and discusses the complex phenomena observed in several materials systems, including the intertwining of charge order and superconductivity in some kagome metals, the modulation of magnetism and topology in some kagome magnets, and the combination of symmetry breaking and Mott physics in ‘breathing’ kagome insulators. The Review also highlights open questions in the field and future research directions in kagome systems.","","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-03-27","","","QN/Ali Lab","","",""
"uuid:c6b28948-bc5a-4d7f-a1f1-4ebea357bfc5","http://resolver.tudelft.nl/uuid:c6b28948-bc5a-4d7f-a1f1-4ebea357bfc5","InfoPrint: Embedding Interactive Information in 3D Prints Using Low-Cost Readily-Available Printers and Materials","Jiang, Weiwei (Anhui Normal University); Wang, C.W. (TU Delft Human-Centred Artificial Intelligence); Sarsenbayeva, Zhanna (University of Sydney); Irlitti, Andrew (University of Melbourne); Wei, Jing (University of Melbourne); Knibbe, Jarrod (University of Melbourne); Dingler, Tilman (University of Melbourne); Goncalves, Jorge (University of Melbourne); Kostakos, Vassilis (University of Melbourne)","","2023","We present a fully-printable method to embed interactive information inside 3D printed objects. The information is invisible to the human eye and can be read using thermal imaging after temperature transfer through interaction with the objects. Prior methods either modify the surface appearance, require customized devices or not commonly used materials, or embed components that are not fully 3D printable. Such limitations restrict the design space for 3D prints, or cannot be readily applied to the already deployed 3D printing setups. In this paper, we present an information embedding technique using low-cost off-the-shelf dual extruder FDM (Fused Deposition Modeling) 3D printers, common materials (e.g., generic PLA), and a mobile thermal device (e.g., a thermal smartphone), by leveraging the thermal properties of common 3D print materials. In addition, we show our method can also be generalized to conventional near-infrared imaging scenarios. We evaluate our technique against multiple design and fabrication parameters and propose a design guideline for different use cases. Finally, we demonstrate various everyday applications enabled by our method, such as interactive thermal displays, user-activated augmented reality, automating thermal triggered events, and hidden tokens for social activities.","3D print; information embedding; near-infrared; Thermal imaging","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-03-27","","","Human-Centred Artificial Intelligence","","",""
"uuid:05a387d7-87a7-4b67-8409-a72ad083527c","http://resolver.tudelft.nl/uuid:05a387d7-87a7-4b67-8409-a72ad083527c","A Long-Term Study Of mmWave Sensing In An Outdoor Urban Scenario","Wang, Weizheng (TU Delft Embedded Systems); Vaidya, G. (TU Delft Networked Systems; Amsterdam Institute for Advanced Metropolitan Solutions (AMS)); Bhattacharjee, A.K. (TU Delft Networked Systems); Fioranelli, F. (TU Delft Microwave Sensing, Signals & Systems); Zuniga, Marco (TU Delft Networked Systems)","O'Conner, L. (editor)","2023","Sensing people with mmWave radars is gaining significant attention. This growing interest is due to two factors: radar monitoring provides more privacy than camera-based alternatives, and radio waves are not as easily blocked as light waves. Most mmWave studies, however, have three common characteristics. They are done indoors, without protecting the sensor (no casing), and the evaluation is performed for short periods of time. To assess the suitability of mmWave sensing in realistic outdoor scenarios, we deploy two nodes to track the flow of pedestrians over a period of three months. This longterm deployment provides three main contributions. First, we follow a detailed process to design a casing that can protect the sensors from harsh environmental conditions. Second, we install our nodes close to a set of cameras that were already deployed in the area. To compare the performance of both types of sensors, we propose a framework that considers the different coverage patterns of cameras and radars. Third, the time frame of our evaluation considers various types of weather, from sunny days to rainy and windy. Our results indicate that mmWave sensors need to be explored further outside the comfort zone of indoor spaces. To the best of our knowledge, this is the first long-term study assessing the reliability of radar sensors in the 60 GHz ISM band.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-03-27","","","Embedded Systems","","",""
"uuid:01a3ced0-59bb-484a-beeb-0bfbe4d904b8","http://resolver.tudelft.nl/uuid:01a3ced0-59bb-484a-beeb-0bfbe4d904b8","Incorporating institutions into optimization-based energy system models","Wang, N. (TU Delft Energie and Industrie)","Herder, P.M. (promotor); Verzijlbergh, R.A. (copromotor); Heijnen, P.W. (copromotor); Delft University of Technology (degree granting institution)","2022","The pledge for a carbon-free energy system in 2050 requires significant investments into renewable energy sources (RES). The relevant questions are: what technologies to select, where to build them, how much the capacities are, and at what cost. In order to answer these techno-economic questions, optimization models are commonly used to sketch a least-cost future energy system. However, the energy system is far more complex than a mathematical model. Although optimization models can provide the least-cost system design, they do not guarantee that we can realize this design because some key aspects are not captured by such models: the impact of public acceptance issues, conflicting interests among stakeholders, and the imperfection of markets. These non-technical aspects are generalized as institutions in this thesis. In a socio- technical system like the energy system, considering both the social aspects, the institutions, and the technical system, is pivotal. Therefore, the goal of this thesis is to improve optimization models by including institutions in energy system planning.
Since institutions are not commonly mentioned in energy system planning models, this thesis starts with standardizing institutions, and we conducted a literature review. The goal is to provide a common ground for discussing institutions and find research trends and gaps in the state-of-the-art. We identified the following research gaps that need deliberate attention: spatial policies, collective decision-making, and bilateral trading with externalities. In this thesis, we developed three models to deal with these institutions. Since these institutions are indispensable in a socio-technical system, including them in optimization models results in socio-technically optimal future energy system designs beyond only the techno-economic optimums.","socio-technical systems; optimization; energy system planning; institutions; spatial policies; energy system optimization models; multi-objective optimization; multi-criteria decision-making; bilateral trading; externalities","en","doctoral thesis","","978-94-6366-630-5","","","","","","","","","Energie and Industrie","","",""
"uuid:fb0fb932-2a5a-44a0-8495-c10b300584e8","http://resolver.tudelft.nl/uuid:fb0fb932-2a5a-44a0-8495-c10b300584e8","Transverse and longitudinal vibrations in axially moving strings","Wang, J. (TU Delft Mathematical Physics)","van Horssen, W.T. (promotor); Wang, J.M. (promotor); Delft University of Technology (degree granting institution)","2022","Varying-length cable systems are widely applied in a vast class of engineering problems which arise in industrial, civil, aerospatial, mechanical, and automotive applications. Due to external excitations, large oscillations can occur when cables are lifted up or down. This phenomenon is caused by resonance. In general, resonance is harmful, and can cause significient deformations and dynamic stresses in machinery and structures, and even can lead to accidents. Therefore, this doctoral dissertation is devoted to the study of transverse and longitudinal resonance phenomena and output feedback stabilization of varying-length cables....","Axially moving string; Resonance; Boundary excitation; Time-varying length; Singular perturbation; Averaging; Backstepping; Vibration control","en","doctoral thesis","","","","","","","","","","","Mathematical Physics","","",""
"uuid:d9752495-9c32-4612-b9c0-e1054c1b764f","http://resolver.tudelft.nl/uuid:d9752495-9c32-4612-b9c0-e1054c1b764f","Navigation and coordination of fixed-wing unmanned aerial vehicles under mission uncertainty","Wang, X. (TU Delft Team Bart De Schutter)","De Schutter, B.H.K. (promotor); Baldi, S. (promotor); Delft University of Technology (degree granting institution)","2022","Unmanned Aerial Vehicles (UAVs) have been emerging as a promising but challenging platform for studying autonomous and cooperative control. This Ph.D. thesis focuses on fixed-wing UAVs which, with their more efficient aerodynamics, can ensure longer flight durations and more autonomy than multi-rotorUAVs. However, in the current state of the art, limited work has been done on deploying formations of fixed-wing UAVs that can operate autonomously even in the presence of large uncertainties. Uncertainties in fixed-wing UAVs include uncertain wind environments, unmodelled longitudinal/lateral dynamics, uncertain load conditions, uncertain communication conditions among the UAVs, and other uncertain factors.
Within this PhD thesis we develope novel adaptive and distributed guidance approaches for fixed-wing UAVs. The following three aspects are studied:
* Vector field guidance under uncertainties
* Distributed formation control with uncertain UAV dynamics
* Testing in the real world to achieve Sim-to-Real transfer","fixed-wing UAV; vector field; unknown dynamics; adaptive guidance control; formation control","en","doctoral thesis","","978-94-6384-387-4","","","","","","","","","Team Bart De Schutter","","",""
"uuid:9ac73753-0036-4b06-9093-d3558bc6182b","http://resolver.tudelft.nl/uuid:9ac73753-0036-4b06-9093-d3558bc6182b","Integrating High-speed Railway Stations and Urban Areas in China: Actors, Processes and Institutions","Wang, B. (TU Delft Urban Development Management)","van Bueren, Ellen (promotor); de Jong, W.M. (promotor); Ersoy, A. (copromotor); Delft University of Technology (degree granting institution)","2022","There is an increasing need for understanding the impacts of institutions on the integrated planning of transport and land use. High-speed railway (HSR) station areas, as nodes in transport networks and mixed-use areas, have become a focus in planning. The fast development of HSR station areas in China causes many problems, such as remote locations, oversized station areas, transfer difficulties, and unsustainable urban development. Facing these problems, this study aims to explore the influences of actors, decision-making processes, and institutions on the planning and development of HSR station areas in China. An analytical framework is built based on Transit-Oriented Development (TOD), Policy Network Theory, Institutional Analysis and Development Framework, and State Entrepreneurialism. Qualitative methods offer an effective way of investigating Chinese governance in the development of HSR station areas, including content analysis, case studies, and interviews. The findings show that HSR station areas are mainly used as a tool to promote urbanization. Both the Chinese national government and local governments have an important role to play in the planning of HSR station areas because they control different resources. Their interactions in the decision-making process, influenced by institutions, determine the location of HSR stations and the size of station areas, and lead to transfer difficulties and slow development of station areas. This dissertation reveals the causes of the development problems of Chinese HSR station areas, demonstrates the drawbacks of the current mechanism, and proposes strategies to promote the integration of transport and land use in China.","High-Speed Railway; station area; Transport planning; Urban Development; China","en","doctoral thesis","A+BE | Architecture and the Built Environment","978-94-6366-613-8","","","","","","","","","Urban Development Management","","",""
"uuid:f43a32d7-cd35-4009-ac13-cfd194f35a86","http://resolver.tudelft.nl/uuid:f43a32d7-cd35-4009-ac13-cfd194f35a86","Associating properties of dissolved organic matter to competitiveness against organic micropollutant adsorption onto activated carbon","Wang, Q. (TU Delft Sanitary Engineering)","Rietveld, L.C. (promotor); Zietzschmann, F.E. (copromotor); Delft University of Technology (degree granting institution)","2022","To eliminate organic micropollutants (OMPs) from (surface) water, activated carbon adsorption is a cost-effective technology to remove a broad range of OMPs without producing any byproducts. However, co-existing dissolved organic matter (DOM), at much higher concentrations (mg C/L) than OMPs (ng/L-μg/L), inducing adsorption competition, can interfere with OMP removal. Direct site competition and pore blocking are two DOM competition mechanisms, and low molecular weight (LMW) DOM has been recognized as the major competitor in the site competition against OMPs. However, the insights into DOM molecular properties are limited with regard to DOM competition. Therefore, the objective of this research was to relate (LMW) DOM properties to the competitiveness against OMPs, clarify the mechanism of direct site competition, and explore a useful DOM surrogate to predict DOM competitiveness.
Model DOM compounds (mDOMs) could be described individually and more accurately with molecular properties than a complex, real DOM matrix in water. To elucidate the impact of LMW DOM characteristics (hydrophobicity/polarity and aromaticity) on DOM competitiveness, fifteen model compounds (mDOM), differed in functional groups (hydroxyl, phenol, carboxyl groups, etc.), were used to represent several elemental structures of LMW DOM. By temporarily occupying adsorption sites prior to OMPs, LMW mDOM was found to be more competitive to inhibit OMP adsorption kinetics than OMP adsorption equilibrium. Although OMPs were more preferentially adsorbed onto activated carbon than mDOM, the large concentration asymmetry (~500 μg DOC/μg OMP) made a few mDOM compounds exert strong competition against OMPs. The mDOM competitiveness increased when compounds were more hydrophobic and more aromatic, whereas π-π interactions were more important to determine mDOM competitiveness than hydrophobic interaction for LMW mDOM compounds. As an integrated indicator, mDOM adsorbability, defined by mDOM adsorption capacity, was considered better to associate with mDOM competitiveness than hydrophobicity and aromaticity individually. The competition was found to be strong between strongly adsorbable mDOM and weakly adsorbable OMPs, where weakly adsorbable mDOM could even co-adsorb with strongly adsorbable OMPs with little to no competition.
To relate DOM adsorbability to competitiveness in natural waters, a two-stage adsorption procedure was designed to differentiate the adsorption of DOM fractions and OMPs by removing variously adsorbable DOM fractions with activated carbon pretreatment and analyzing the competitiveness of the remaining DOM fractions. Our results demonstrated that adsorbable (LMW) DOM was not necessarily competitive against OMPs. In addition, an increasing amount of DOM competitors was observed against the weaker adsorbable OMPs, compared to their stronger adsorbable counterparts. Similarly, more DOM competitors were identified at high initial OMP concentrations, due to the increased loading of OMPs on activated carbon, highlighting the variable roles (varying competitiveness/ complementary adsorption) of differently adsorbable DOM fractions in competition.
To elucidate the role of molecular weight (MW), polarity and aromaticity in DOM competition from a natural DOM with a complex molecular composition, activated carbon and anion exchange resin (AER) pretreatment served for differentiating competitive DOM from natural DOM. Ultrahigh-resolution Fourier transform mass spectrometry was employed for the DOM analysis at the molecular level. A large percentage of molecular formulas in untreated DOM was PAC-absorbable (97.8% for 40 mg PAC/L), while ~75% of PAC-absorbable formulas were considered poorly competitive, since these molecular formulas were not detected in DOM remaining after AER pretreatment that was highly competitive. The semi-quantitative analysis revealed that aromaticity was the dominant factor for LMW DOM adsorbability and competitiveness. In contrast, with higher MW, the competitiveness of an increasing number of aromatic DOM compounds was diminished due to strong dissociation induced by relatively high polarity.
Finally, the interference of ozone-modified NOM with the adsorption of 2-methylisoborneol (MIB, an odorous OMP) was studied in three natural waters and one standard humics solution in order to study how ozonation influences the competitiveness of DOM with different MW distributions. In the three natural waters, it was found that reducing NOM competition against MIB was found to coincide with increasing ozone consumption. The cleavage of the macromolecules in a standard humics solution, with larger molecular weight and higher aromaticity than the humics in natural waters, only induced a slightly stronger competition under low/moderate ozone consumptions. Overall, the declined aromaticity outweighed the produced LMW DOM in the competitiveness of DOM against MIB in ozonated natural waters. The UV absorbance of the LMW DOM was better correlated with the competitiveness of ozonated/non-ozonated waters than the LMW DOM concentration itself, underlining the role of LMW hydrophobic aromatics in competitive adsorption prediction.
From this thesis, it could thus be concluded that the DOM competition against OMPs is not ubiquitous for all (adsorbable, LMW) DOM fractions. The amount of DOM competitors, as well as their competitiveness, strongly varies with to OMP adsorbability and the initial OMP concentrations (i.e., the concentration asymmetry). For LMW DOM, aromaticity was a key characteristic to promote DOM competitiveness, while the high polarity reduced the DOM competitiveness by DOM dissociation (and thus high hydrophilicity/polarity). To project the competitiveness of ozonated DOM of which the hydrophobicity and aromaticity were simultaneously diminished, LMWUV can then be a handy DOM surrogate instead of LMW DOM concentration itself.
crack propagation characteristics at the virgin-aged binder interface in the asphalt mixture with RAM. It was found that the blended binder of virgin and aged binders, and its interfaces with virgin and aged binders appeared to be the crack propagation zones. The relatively more significant matrix contraction of virgin binder and stiffer aged binder at a low temperature can cause more considerable tensile stress at the blended binder and its interfaces. Consequently, interfacial crack propagation became more profound and decreased the low temperature cracking resistance.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Pavement Engineering","","",""
"uuid:f829a427-d4c3-46e2-9092-85898b431117","http://resolver.tudelft.nl/uuid:f829a427-d4c3-46e2-9092-85898b431117","摩擦型轨枕道床的横向阻力研究","Guo, Y. (TU Delft Railway Engineering); Wang, Xinyu (Beijing Jiaotong University); Lian, Dong (Shandong High Speed Railway Construction Equipment Co., Weifang); Wan, Hongyu (Beijing Jiaotong University); Jing, Guoqing (Beijing Jiaotong University)","","2022","The Sichuan−Tibet railway is built under some difficult situations, including limited ballast bed profile, frequent earthquakes and large diurnal temperature variation. These difficulties cause insufficient lateral resistance of ballasted track, which is an urgent problem for the stability and resilience of the continuously welded rail (CWR). Aiming to improve and quantify the stability and resilience of CWR, the lateral resistance of frictional sleepers (designed as that normal sleeper with arrowhead shape groove) is evaluated with the single sleeper push test (SSPT). By performing SSPT, the increment of lateral resistance of ballast bed with frictional sleepers is measured. Shapes of sleeper grooves are properly designed and optimized (three groove shapes with the same size and volume but different arrowhead directions). Whether frictional sleeper applied to ballast bed (reduced ballast shoulder width) will provide enough lateral resistance for the ballast bed at Sichuan−Tibet railway line. Results show that frictional sleepers can increase the lateral resistance by minimum 7% and maximum 21%. Arrowhead directions significantly influence the lateral resistance, which is increased by 7% (same pushing direction) and 24% (opposite pushing direction), compared to normal sleepers. Therefore, strict attention should be paid to the laying direction when laying in curved sections of ballasted track. After reducing the ballast shoulder width from 50 cm to 30 cm, using the frictional sleeper (single arrowhead direction pushed in reversed direction) can still provide enough lateral resistance, which is the same value as a mono-block Type Ⅲ sleeper with 50 cm shoulder width.","Frictional sleeper; Lateral resistance; Resilience; Sichuan−Tibet railway; Single sleeper push test","zh","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Railway Engineering","","",""
"uuid:c2331ae6-2396-4d71-b9cd-6a0e7a047b86","http://resolver.tudelft.nl/uuid:c2331ae6-2396-4d71-b9cd-6a0e7a047b86","Efficient Angle Estimation for MIMO Systems via Redundancy Reduction Representation","Zhang, Yu (Nanjing University of Aeronautics and Astronautics); Wang, Yue (George Mason University); Tian, Zhi (George Mason University); Leus, G.J.T. (TU Delft Signal Processing Systems); Zhang, Gong (Nanjing University of Aeronautics and Astronautics)","","2022","This paper proposes an efficient direction of departure (DOD) and direction of arrival (DOA) estimation method for multi-input multi-output (MIMO) systems. For uncorrelated scenarios, the redundancy of the covariance matrix is first exploited by establishing its concise representation through redundancy reduction, which transforms the original large-size covariance matrix into a smaller-size matrix without loss of useful angle information. Then, the resulting transformed matrix, which retains a salient structure, permits efficient two-dimensional (2D) angle estimators working on a reduced-size problem for DOD and DOA estimation. Compared with conventional subspace-based methods, the proposed method incorporating an appropriate 2D angle estimator is more computationally efficient and can achieve higher estimation accuracy for small numbers of snapshots and low signal-to-noise ratios, which are verified by simulation results.","DOD and DOA estimation; MIMO systems; redundancy reduction representation; transformation matrix construction","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-10-10","","","Signal Processing Systems","","",""
"uuid:1f3ae5d7-166d-487e-b7c8-5bb7c98d32f9","http://resolver.tudelft.nl/uuid:1f3ae5d7-166d-487e-b7c8-5bb7c98d32f9","An efficient adaptive implicit scheme with equivalent continuum approach for two-phase flow in fractured vuggy porous media","Wang, L. (GeoRessources Lab); Golfier, Fabrice (GeoRessources Lab); Tinet, Anne-Julie (GeoRessources Lab); Chen, Weizhong (Chinese Academy of Sciences); Vuik, Cornelis (TU Delft Delft Institute of Applied Mathematics)","","2022","This work investigates numerical method and equivalent continuum approach (ECA) of fluid flow in fractured porous media. The commonly used discrete fracture model (DFM) without upscaling needs full discretization of all fractures. It enjoys the merit of capturing each fracture accurately but will get in trouble with mesh partition and low computational efficiency, especially when a complex geometry is involved. In this study, we develop an efficient implicit scheme with adaptive iteration, in which an improved ECA is devised and then integrated in this scheme. Numerical studies show that the proposed numerical scheme improves the convergence condition and computational efficiency. Then, a test is conducted to demonstrate the feasibility of using superposition principle of permeability tensor in upscaling. Based on these, different strategies are applied to simulate fluid flow in fracture networks with a complex geometry. It is demonstrated that the proposed ECA is able to reproduce the results computed by DFM. The accuracy depends on resolution of background grids. The presented method enjoys a low computational cost and desirable convergence performance compared with the standard DFM in which equivalent continuum is not considered.","Fractured porous media; Two-phase flow; Upscaling; Equivalent permeability tensor; Implicit scheme","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-10-04","","","","","",""
"uuid:f5f9693b-025e-49b7-b3ae-1d36b87f6f36","http://resolver.tudelft.nl/uuid:f5f9693b-025e-49b7-b3ae-1d36b87f6f36","High-Voltage and High-Current IGBT Press-pack Module for Power Grid","Tan, C. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology); Wang, S. (TU Delft Bio-Electronics; Southern University of Science and Technology); Liu, X. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology); Jiang, Jing (Fudan University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Ye, H. (TU Delft Electronic Components, Technology and Materials; Chongqing University)","","2022","On the basis of the development and application requirements of flexible DC transmission techniques, a 1 kA/10 kV half-bridge IGBT press-pack module is studied. The module is composed of three subunits in series, and each subunit consists of IGBT chips in parallel. In order to solve the problem of chips failure caused by non-uniform rigid-contacting pressure in the press-pack modules, the elastic-contacting structure is designed to ensure excellent electrical connection between chips and contact terminal. During the operating conditions, the heat generated by IGBT chips can induce the increasing of internal temperature of the module, affecting the reliability of the module. A cooling structure is introduced between the subunits to solve the heat dissipation problem of the module. In addition, the thermal analysis of subunit and the cooling structure is performed by using the finite element simulation, and the chip layout and water-cooling scheme are optimized. The testing of electrical parameters of the IGBT module is also conducted.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Components, Technology and Materials","","",""
"uuid:54a398de-9d5d-4840-b88c-25b7c3decc14","http://resolver.tudelft.nl/uuid:54a398de-9d5d-4840-b88c-25b7c3decc14","Adaptive Vector Field Guidance Without a Priori Knowledge of Course Dynamics and Wind","Wang, X. (TU Delft Team Bart De Schutter); Roy, Spandan (International Institute of Information Technology); Fari, S. (TU Delft Team Bart De Schutter); Baldi, S. (TU Delft Team Bart De Schutter)","","2022","The high maneuverability of fixed-wing unmanned aerial vehicles (UAVs) exposes these systems to several dynamical and parametric uncertainties, severely affecting the fidelity of modeling and causing limited guidance autonomy. This article shows enhanced autonomy via adaptation mechanisms embedded in the guidance law: a vector-field method is proposed that does not require a priori knowledge of the UAV course time constant, coupling effects, and wind amplitude/direction. Stability and performance are assessed using the Lyapunov theory. The method is tested on software-in-the loop and hardware-in-the-loop UAV platforms, showing that the proposed guidance law outperforms state-of-the-art guidance controllers and standard vector-field approaches in the presence of significant uncertainty.","Adaptive guidance; adaptive sliding-mode control; Adaptive systems; Aerodynamics; Autonomous aerial vehicles; fixed-wing unmanned aerial vehicles (UAV); Navigation; Orbits; Standards; Uncertainty; unknown dynamics; vector field (VF)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Team Bart De Schutter","","",""
"uuid:2f8ee2b3-b3ab-457f-8756-1c06bdf6da31","http://resolver.tudelft.nl/uuid:2f8ee2b3-b3ab-457f-8756-1c06bdf6da31","Active Disturbance Rejection Control for Uncertain Nonlinear Systems With Sporadic Measurements","He, K. (TU Delft Team Bart De Schutter; Beihang University); Dong, Chaoyang (Beihang University); Wang, Qing (Beihang University)","","2022","This paper deals with the problem of active disturbance rejection control (ADRC) design for a class of uncertain nonlinear systems with sporadic measurements. A novel extended state observer (ESO) is designed in a cascade form consisting of a continuous time estimator, a continuous observation error predictor, and a reset compensator. The proposed ESO estimates not only the system state but also the total uncertainty, which may include the effects of the external perturbation, the parametric uncertainty, and the unknown nonlinear dynamics. Such a reset compensator, whose state is reset to zero whenever a new measurement arrives, is used to calibrate the predictor. Due to the cascade structure, the resulting error dynamics system is presented in a non-hybrid form, and accordingly, analyzed in a general sampled-data system framework. Based on the output of the ESO, a continuous ADRC law is then developed. The convergence of the resulting closed-loop system is proved under given conditions. Two numerical simulations demonstrate the effectiveness of the proposed control method.","Active disturbance rejection control (ADRC); extended state observer (ESO); sampled measurements; uncertain nonlinear systems","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Team Bart De Schutter","","",""
"uuid:c1b7f626-4294-498f-ba13-8fc04f7283ba","http://resolver.tudelft.nl/uuid:c1b7f626-4294-498f-ba13-8fc04f7283ba","Rural Post-Earthquake Resettlement Mode Choices: Empirical Case Studies of Sichuan, China","Zhao, Lei (Chengdu University of Technology); Zhou, Sifan (Chengdu University of Technology); Zhong, Jinglin (Chengdu University of Technology); Ao, Yibin (Chengdu University of Technology); Wang, Yan (Sichuan College of Architectural Technology); Wang, T. (TU Delft Design & Construction Management); Chen, Yunfeng (Purdue University)","","2022","Earthquakes occur frequently in rural areas of Sichuan, China, causing huge damage and high mortality. The built environment plays a significant role in providing residents with safe and resilient settlements in such areas. There is yet little research on how rural families in developing countries cope with geological disasters like earthquakes, and how built environmental factors would influence their resettlement choices which would directly affect their quality of life afterward. Urban planning activities should be accompanied by these insights to design and create human-centric resettlements accordingly. In this study, the resettlement choices after three major earthquakes in Sichuan were studied for this reason. Random sampling and face-to-face questionnaire surveys were combined with factor analysis and binary logistic regression to understand the resettlement modes desired by the residents and the influencing factors. The results show that residents who have lived in their current places long and whose houses were not built recently are more likely to choose the in-situ resettlement. Accessibility to employment and public services has a significant impact on residents' choice of in-situ resettlement or reallocated resettlement, and so does the previous resettlement experience. The research results can provide useful suggestions for Chinese rural area post-earthquake resettlement planning following a human-centric approach with empirical data.","post-earthquake resettlement mode; influencing factor; factor analysis; binary logistic regression; Wenchuan earthquake; Changning earthquake; Lushan earthquake","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:ec3078f1-c2d3-4413-80d7-d25e9514a7e9","http://resolver.tudelft.nl/uuid:ec3078f1-c2d3-4413-80d7-d25e9514a7e9","Rules for the Governance of Transport and Land use Integration in High-speed Railway Station Areas in China: The Case of Lanzhou","Wang, B. (TU Delft Urban Development Management); Ersoy, A. (TU Delft Urban Development Management); van Bueren, Ellen (TU Delft Management in the Built Environment); de Jong, Martin (Erasmus Universiteit Rotterdam; Fudan University)","","2022","The rapid high-speed railway development in China has faced many institutional challenges for the integrated development of transport and land use in station areas. This paper aims to gain insight into the institutional rules that structure the actors’ interactions and how they influence the integrated development in station areas. The Institutional Analysis and Development framework has been applied to a specific action situation, named Lanzhou West HSR station area in China. The findings from interviews, document analysis, and field visits reveal that Chinese institutional rules obstruct interactions between actors, thereby hampering the integrated development of functions in HSR station areas.","Rules; institutional analysis; integration of transport and land use; high-speed railway; station area","en","journal article","","","","","","","","","","Management in the Built Environment","Urban Development Management","","",""
"uuid:a89ba010-1640-4eb0-96bc-7be543d056f9","http://resolver.tudelft.nl/uuid:a89ba010-1640-4eb0-96bc-7be543d056f9","Vision-Based Nonlinear Incremental Control for A Morphing Wing with Mechanical Imperfections","Sun, B. (TU Delft Control & Simulation); Mkhoyan, T. (TU Delft Arts & Crafts; TU Delft Aerospace Structures & Computational Mechanics); van Kampen, E. (TU Delft Control & Operations; TU Delft Control & Simulation); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics)","","2022","Morphing structures have acquired much attention in the aerospace community because they enable an aircraft to actively adapt its shape during flight, leading to fewer emissions and fuel consumption. Researchers have designed, manufactured, and tested a morphing wing named SmartX-Alpha, which can actively alleviate loads while achieving the optimal lift distribution. However, the widely existing mechanical imperfections can degrade the performance of the morphing wing and even lead to instabilities. To tackle these issues, this article proposes a vision-based adaptive control approach to actively compensate for mechanical imperfections. In this approach, an incremental model is constructed online to identify the system dynamics using servo commands and vision measurements, and then, nonlinear dynamic inversion control is applied based on the identified model. This data-driven control approach with visual feedback has been validated by real-world experiments on the SmartX-Alpha. The results demonstrate that the vision-based system combined with the proposed control methodology can actively compensate for mechanical imperfections with minimal adjustments to the actual system design. Compared to a controller that only uses a feedforward input-output mapping, this proposed approach improves the system performance and decreases the tracking errors by more than 62% despite disturbances. The results collectively demonstrate the effectiveness of the proposed control system, which sets a foundation for realizing morphing in next-generation aircraft.","Adaptation models; Aerodynamics; Aerospace control; datadriven control; Hysteresis; incremental model; mechanical imperfections; Morphing wing; Nonlinear dynamical systems; Shape; System dynamics; vision-based control","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-01-09","","Control & Operations","Control & Simulation","","",""
"uuid:160db5be-d87b-4bee-a85c-bef2fc223f78","http://resolver.tudelft.nl/uuid:160db5be-d87b-4bee-a85c-bef2fc223f78","Reliability Analysis of FinFET-Based SRAM PUFs for 16nm, 14nm, and 7nm Technology Nodes","Masoumian, S. (TU Delft Computer Engineering; Intrinsic ID B.V.); Selimis, Georgios (Intrinsic ID B.V.); Wang, Rui (Intrinsic ID B.V.); Schrijen, Geert-Jan (Intrinsic ID B.V.); Hamdioui, S. (TU Delft Quantum & Computer Engineering); Taouil, M. (TU Delft Computer Engineering)","","2022","SRAM Physical Unclonable Functions (PUFs) are among other things today commercially used for secure primitives such as key generation and authentication. The quality of the PUFs and hence the security primitives, depends on intrinsic variations which are technology dependent. Therefore, to sustain the commercial usage of PUFs for cutting-edge technologies, it is important to properly model and evaluate their reliability. In this work, we evaluate the SRAM PUF reliability using within class Hamming distance (WCHD) for 16nm, 14nm, and 7nm using simulations and silicon validation for both low-power and high-performance designs. The results show that our simulation models and expectations match with the silicon measurements. From the experiments, we conclude the following: (1) SRAM PUF is reliable in advanced FinFET technology nodes, i.e., the noise is low in 16nm, 14nm, and 7nm, (2) temperature variations have a marginal impact on the reliability, and (3) both low-power and high-performance SRAMs can be used as a PUF without excessive need of error correcting codes (ECCs).","FinFET; measurements; reliability; simulation model; SRAM PUF","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","Quantum & Computer Engineering","Computer Engineering","","",""
"uuid:5dbc5148-f5a7-4102-84c5-f10ca6ff00e3","http://resolver.tudelft.nl/uuid:5dbc5148-f5a7-4102-84c5-f10ca6ff00e3","Effects of biological activated carbon filter running time on disinfection by-product precursor removal","Wang, Feifei (Shanghai University); Pan, Jiazheng (Shanghai University); Hu, Yulin (Shanghai University); Zhou, Jie (Shanghai University); Wang, Haoqian (Shanghai University); Huang, Xin (Shanghai University); Chu, Wenhai (Tongji University); van der Hoek, J.P. (TU Delft Sanitary Engineering; Waternet)","","2022","Biological activated carbon (BAC) filtration is usually considered to be able to decrease formation potentials (FPs) of disinfection by-products (DBPs) in drinking water treatment plant (DWTP). However, BAC filters with long running time may release microbial metabolites to effluents and therefore increase FPs of nitrogenous DBPs with high toxicity. To verify this hypothesis, this study continuously tracked BAC filters in a DWTP for one year, and assessed effects of old (running time 8–9 years) and new (running time 0–13 months) BAC filters on FPs of 15 regulated and unregulated DBPs. Results revealed that dissolved organic carbon (DOC) removal was slightly higher in the new BAC than the old one. All fluorescent components of dissolved organic matter evidently declined after new BAC filtration, but fulvic acid-like and soluble microbial product-like substances increased after old BAC filtration, which could be caused by microbial leakage. Correspondingly, new BAC filter generally removed more DBP FPs than the old one. 46.5% HAA7 FPs from chlorination and 44.3% THM4 FPs from chloramination were removed by new BAC filter. However, some DBP FPs, especially HAN FPs, were poorly removed or even increased by the old BAC filter. Proteobacteria could be a main contributor for DBP precursor removal in BAC filters. Herminiimonas, most abundant genera in new BAC filter, may explain its better DOC and UV254 removal performance and lower DBP FPs, while Bradyrhizobium, most abundant genera in old BAC filter, might produce more extracellular polymeric substances and therefore increased N-DBP FPs in old BAC effluent. This study provided insight into variations of DBP FPs and microbial communities in the new and old BAC filters, and will be helpful for the optimization of DWTP design and operation for public health.","Biological activated carbon; Chlorination; Chloramination; Disinfection by-products; Formation potentials; High-throughput sequencing","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-11-14","","","Sanitary Engineering","","",""
"uuid:547db3fe-b6d2-4533-aa9d-e335d6b3cf04","http://resolver.tudelft.nl/uuid:547db3fe-b6d2-4533-aa9d-e335d6b3cf04","Analysis of longitudinal oscillations in a vertically moving cable subject to nonclassical boundary conditions","Wang, J. (TU Delft Mathematical Physics; Beijing Institute of Technology); van Horssen, W.T. (TU Delft Mathematical Physics)","","2022","In this paper, we study a model of a flexible hoisting system, in which external disturbances exerted on the boundary can induce large vibrations, and so damage to the performance of the system. The dynamics is described by a wave equation on a slow time-varying spatial domain with a small harmonic boundary excitation at one end of the cable, and a moving mass at the other end. Due to the slow variation of the cable length, a singular perturbation problem arises. By using an averaging method, and an interior layer analysis, many resonance manifolds are detected. Further, a three time-scales perturbation method is used to construct formal asymptotic approximations of the solutions. It turns out that for a given boundary disturbance frequency, many oscillation modes jump up from order ε amplitudes to order ε amplitudes, where ε is a small parameter with 0","Resonance; Boundary excitation; Time-varying length; singular perturbation; Averaging","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-12-05","","","Mathematical Physics","","",""
"uuid:874d6c38-9b9d-4a7b-88d2-759cd43161e5","http://resolver.tudelft.nl/uuid:874d6c38-9b9d-4a7b-88d2-759cd43161e5","Modeling the Spectral Sensitivity of Singlet Oxygen Induced by Photochemical Reactions in Cells","Wang, T. (TU Delft Electronic Components, Technology and Materials); Dong, Jianfei (Chinese Academy of Sciences)","","2022","Anti-fungal blue light (ABL) therapies are based on the photochemical reaction of endogenous photosensitizer (PS) in fungal cells. Knowing the spectral sensitivity of these cells for the ability to generate singlet oxygen is thus important to determine the most effective wavelength of such light therapies, and thereby to design ABL therapeutic devices, e.g., by light emitting diodes. We propose a modeling method of such spectral sensitivity in this work, based on the absorption spectra of cells and other inherent characteristic parameters, i.e., singlet oxygen quantum yield and the extinction coefficient of the endogenous PS. Specifically, the absorption spectra are determined by the PSs inside the fungus Candida albicans and human epithelial cells. Then, the concentration of PS in those two types of cells was measured by high-performance liquid chromatography (HPLC) assays. The HPLC assays show that the coproporphyrin (CP) is the main PS in C. albicans, accounting for 60% of the total PS. The simulation results demonstrate that the 390420nm light can stimulate the PS in the cells to generate more singlet oxygen in C. albicans than in epithelial cells; and this range is the same as the CP Soret band. In contrast, the light with wavelengths >450nm is less effective in exciting the PS in C. albicans, and leads to more singlet oxygen generation in V.E. cells than shorter wavelength. We thus conclude that 390420nm light is the most effective range for inhibiting C. albicans with the least damage to human host cells.","Anti-fungal blue light therapy; singlet oxygen; spectral sensitivity; photosensitizer","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Components, Technology and Materials","","",""
"uuid:f8161b4b-7c54-495e-918b-4ec16ade4869","http://resolver.tudelft.nl/uuid:f8161b4b-7c54-495e-918b-4ec16ade4869","Livelihood Capital Effects on Famers’ Strategy Choices in Flood-Prone Areas: A Study in Rural China","Ao, Yibin (Chengdu University of Technology); Tan, Ling (Chengdu University of Technology); Feng, Qiqi (Chengdu University of Technology); Tan, Liyao (Chengdu University of Technology); Li, Hongfu (Chengdu University of Technology); Wang, Yan (Sichuan College of Architectural Technology); Wang, T. (TU Delft Design & Construction Management); Chen, Yunfeng (Purdue University)","","2022","The global climate change has resulted in huge flood damages, which seriously hinders the sustainable development of rural economy and society and causes famers’ livelihood problems. In flood-prone areas, it is imperative to actively study short and long-term strategies and solve farmers’ livelihood problems accordingly. Following the sustainable development analysis framework proposed by the Department for International Development (DFID), this study collects empirical data of 360 rural households in six sample villages in the Jialing River Basin of Sichuan Province, China through a village-to-household field questionnaire and applies the Multinominal Logit Model (MNL) to explore the influence of farmer households’ capital on livelihood strategy choice. Research results show that: (1) In human capital category, the education level of the household head has a significant positive impact on the livelihood strategies of farmers’ families; (2) In physical capital category, farmer households with larger space have more funds to choose among flood adaptation strategies; (3) In natural capital category, house location and the sale of family property for cash have the greatest negative impact on farmers’ livelihood strategies; (4) Rural households with more credit opportunities in financial capital are more willing to obtain emergency relief funds; (5) Farmers’ families helped by the village for a long time will probably not choose to move to avoid floods, but are more likely to choose buying flood insurance. This study provides an empirical reference for effective short and long term prevention and mitigation strategies design and application in rural in flood-prone areas","farmers’ household; flood disaster; capital; livelihood strategy","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:0f9bef1b-4c72-4218-9c93-8a88031a8818","http://resolver.tudelft.nl/uuid:0f9bef1b-4c72-4218-9c93-8a88031a8818","3D-TSV: The 3D trajectory-based stress visualizer","Wang, Junpeng (Technische Universität München); Neuhauser, Christoph (Technische Universität München); Wu, J. (TU Delft Materials and Manufacturing); Gao, Xifeng (Tencent America, Seattle); Westermann, Rüdiger (Technische Universität München)","","2022","In this paper, we present novel algorithms for visualizing the three mutually orthogonal principal stress directions in 3D solids under load and we discuss the efficient integration of these algorithms into the 3D Trajectory-based Stress Visualizer (3D-TSV), a visual analysis tool for the exploration of the principal stress directions of 3D stress field. In the design of 3D-TSV, several perceptual problems have been solved. We present a novel algorithm for generating a space-filling and evenly spaced set of stress lines. The algorithm obtains a more
regular appearance by considering the locations of lines, and enables the extraction of a level-of-detail representation with adjustable sparseness of the trajectories along a certain stress direction. A new combined visualization of two principal directions via oriented ribbons enables to convey ambiguities in the orientation of the principal stress directions. Additional depth cues have been added to improve the perception of the spatial relationships between trajectories. 3D-TSV provides a modular and generic implementation of key algorithms required for a trajectory-based visual analysis of principal stress directions, including the automatic seeding of space-filling stress lines, their extraction using numerical schemes, their mapping to an effective renderable
representation, and rendering options to convey structures with special mechanical properties. 3D-TSV is accessible to end users via a C++- and OpenGL-based rendering frontend that is seamlessly connected to a
MatLab-based extraction backend. The code (BSD license) of 3D-TSV as well as scripts to make ANSYS and ABAQUS simulation results accessible to the 3D-TSV backend are publicly available.","","en","journal article","","","","","","","","","","","Materials and Manufacturing","","",""
"uuid:8dd67149-1ec1-4854-81be-701457962dec","http://resolver.tudelft.nl/uuid:8dd67149-1ec1-4854-81be-701457962dec","Households’ Earthquake Disaster Preparedness Behavior: The Role of Trust in and Help From Stakeholders","Ao, Yibin (Chengdu University of Technology); Tan, Liyao (Chengdu University of Technology); Zhong, Jinglin (Chengdu University of Technology); Zhang, Hongying (Chengdu University of Technology); Wang, Yan (Sichuan College of Architectural Technology); Wang, T. (TU Delft Design & Construction Management)","","2022","Earthquake is one of the most serious natural disasters. Taking scientific and reasonable earthquake preparedness measures can effectively reduce casualties and economic losses caused by earthquakes. It is important to understand how residents choose such earthquake preparedness measures to guide them accordingly. However, the current research has failed to address rural areas in developing countries and has inconsistency conclusions for two aspects related to stakeholders involved: the assistance the victims can get from stakeholders for applying earthquake preparedness measures and the trust in stakeholders’ disaster relief abilities. In this study, the rural residents affected by Wenchuan earthquake, Ya’an earthquake and Yibin earthquake were taken as the research objects, and 674 valid questionnaires were obtained through field household surveys. A Multinominal Logit Model (MNL) was constructed to explore the influence of villagers’ trust in the disaster relief ability of stakeholders and the help they can get from stakeholders on their preparedness behavior. The results show that the less trust the villagers have on the government and the community, and the more help they can get from the outside while preparing measures, the more inclined they are to take the disaster preparedness measures. Furthermore, the education level of villagers in earthquake-stricken areas has significant positive impacts on people’s earthquake preparedness behavior. People who are not born in rural areas are more likely to take earthquake preparedness measures. In addition, male, young and married villagers are more likely to take earthquake preparedness measures in their daily lives. This study enriches the theory of rural disaster prevention and mitigation, and provides reference for the practice of disaster prevention and mitigation in earthquake-stricken rural areas.","multi-stakeholders; MNL model; trust; help; villagers earthquake preparedness behavior","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:3713c378-9e59-48e5-bc39-a415762b938c","http://resolver.tudelft.nl/uuid:3713c378-9e59-48e5-bc39-a415762b938c","Output feedback stabilisation of an axially moving string subject to a spring-mass-dashpot","Wang, Jun-Min (Beijing Institute of Technology); Wang, J. (TU Delft Mathematical Physics; Beijing Institute of Technology); Zhang, Han-Wen (Beijing Institute of Technology)","","2022","In this paper, we consider the output feedback stabilisation of an axially moving string system subject to a spring-mass-dashpot boundary condition. By constructing an invertible backstepping transformation, we design a state feedback controller to stabilise the system. Next, we present an observer to estimate the states of the system, and based on the estimated states, we design an output-feedback controller. The closed-loop system is proved to be exponentially stable by Lyapunov analysis. Numerical simulations are presented to verify the effectiveness of the proposed controller.","backstepping; Moving string; PDE-ODE; spring-mass-dashpot; vibration control","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Mathematical Physics","","",""
"uuid:e7080c12-62ba-4f9e-932a-99d921743365","http://resolver.tudelft.nl/uuid:e7080c12-62ba-4f9e-932a-99d921743365","Assessment of Parkinson's Disease Severity from Videos Using Deep Architectures","Yin, Zhao (Student TU Delft); Geraedts, Victor Jacobus (Leiden University Medical Center); Wang, Z. (TU Delft Pattern Recognition and Bioinformatics); Contarino, Maria Fiorella (Leiden University Medical Center); Dibeklioglu, H. (TU Delft Pattern Recognition and Bioinformatics); van Gemert, J.C. (TU Delft Pattern Recognition and Bioinformatics)","","2022","Parkinson's disease (PD) diagnosis is based on clinical criteria, i.e., bradykinesia, rest tremor, rigidity, etc. Assessment of the severity of PD symptoms with clinical rating scales, however, is subject to inter-rater variability. In this paper, we propose a deep learning based automatic PD diagnosis method using videos to assist the diagnosis in clinical practices. We deploy a 3D Convolutional Neural Network (CNN) as the baseline approach for the PD severity classification and show the effectiveness. Due to the lack of data in clinical field, we explore the possibility of transfer learning from non-medical dataset and show that PD severity classification can benefit from it. To bridge the domain discrepancy between medical and non-medical datasets, we let the network focus more on the subtle temporal visual cues, i.e., the frequency of tremors, by designing a Temporal Self-Attention (TSA) mechanism. Seven tasks from the Movement Disorders Society - Unified PD rating scale (MDS-UPDRS) part III are investigated, which reveal the symptoms of bradykinesia and postural tremors. Furthermore, we propose a multi-domain learning method to predict the patient-level PD severity through task-assembling. We show the effectiveness of TSA and task-assembling method on our PD video dataset empirically. We achieve the best MCC of 0.55 on binary task-level and 0.39 on three-class patient-level classification.","deep learning; Diseases; Feature extraction; multi-domain learning; Parkinson's disease (PD); self-attention; severity classification; Task analysis; Three-dimensional displays; Training; Transfer learning; transfer learning; Videos","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:305177f9-573a-4d3b-83c1-39b49ea06a3a","http://resolver.tudelft.nl/uuid:305177f9-573a-4d3b-83c1-39b49ea06a3a","Neural-adaptive constrained flight control for air ground recovery under terrain obstacles","Su, Zikang (Nanjing University of Aeronautics and Astronautics); Wang, X. (TU Delft Transport and Planning); Wang, Honglun (Beihang University)","","2022","This article contrives a neural-adaptive constrained controller of the cable towed air-ground recovery system subject to terrain obstacles, unmeasurable cable tensions, trailing vortex, wind gust, and actuator saturation. In air-ground recovery system modeling, the towed vehicle's nominal 6 DOF affine nonlinear dynamics and the cable system's finite links-joints dynamics are formulated. To achieve accurate air-ground recovery under terrain obstacles, an asymmetric barrier Lyapunov function-based flight controller of the towed vehicle is proposed, by transforming the terrain obstacles into time-varying constraints on the vehicle's trajectory. Then, to approximate the towed vehicle's lumped unknown dynamics caused by the unmeasurable cable tensions and airflows, several echo state network (ESN) approximators are established for velocity and attitude subsystems. By using the state approximation errors-based neural weights learning strategy and minimal learning parameter technique, these ESNs possess better transient behaviors and lower online computational burden. Furthermore, the actuator saturation is automatically monitored and released, by incorporating a specially designed auxiliary compensating system into the angular rate control law for compensation. The stability of the closed-loop system is analyzed. Finally, numerical simulations under two air-ground recovery scenarios are performed to demonstrate the performance of the proposed controller.","actuator saturation; Actuators; Aerodynamics; Aerospace control; air-ground recovery; Aircraft; constrained flight control; neural approximation; Nonlinear dynamical systems; towed vehicle; Trajectory; Vehicle dynamics","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:b96015d2-2592-4cc6-8af3-5fd0a8336e58","http://resolver.tudelft.nl/uuid:b96015d2-2592-4cc6-8af3-5fd0a8336e58","Prediction of mechanical solutions for a laminated LCEs system fusing an analytical model and neural networks","Wang, Jue (Hohai University); Yuan, Weiyi (Hohai University); Li, Z. (TU Delft Electronic Components, Technology and Materials); Zhu, Yingcan (University of Southern Queensland); Santos, Thebano (Ministry of Science, Technology, Innovation and Communication); Fan, J. (TU Delft Electronic Components, Technology and Materials; Fudan University)","","2022","This paper presents a convenient and efficient method to predict the mechanical solutions of a laminated Liquid Crystal Elastomers (LCEs) system subjected to combined thermo-mechanical load, based on a back propagation (BP) neural network which is trained by machine learning from a database established by analytical solutions. Firstly, the general solutions of temperature, displacement, and stress of any single layer in the LCEs system are obtained by solving the two-dimensional (2D) governing equations of both heat conduction and thermoelasticity. Then, the unknown coefficients in above general solutions are determined by a transfer-matrix method based on the continuity condition at the interface of adjacent layers and the combined thermo-mechanical loads condition at the surface of the LCEs system. The formula derivation and calculator program are verified through convergence studies and comparisons with FEM results. Finally, a database with displacements of LCEs system in a temperature field subjected to 561 sets of mechanical loads is established based on the presented analytical model. The BP neural network based on above database is further applied to establish the relationship between deformation and mechanical load to predict the elastic deformation of the LCEs system in a temperature field subjected to a mechanical load. Moreover, the BP network can also inverse the coefficients of mechanical load which induces the specific deformation in a temperature field. The numerical examples show that: (1) The deformation of a laminated LCEs system due to thermal load is limited within the range of human temperature changes from 36 °C to 40 °C. (2) The thickness of the LCE is a sensitive parameter on the deformation at the bottom surface of the system. (3) The accuracy of predicted displacements induced by the thermo-mechanical load and the inversed mechanical load based on deformation of the LCEs system in a temperature field using BP neural network reaches 99.6% and 98.5% respectively.","Analytical solution; BP neural Network; Laminated liquid crystal elastomers system; Thermo-mechanical load","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Components, Technology and Materials","","",""
"uuid:3a326c93-ad32-49cd-8ae3-1987d4f1b3b5","http://resolver.tudelft.nl/uuid:3a326c93-ad32-49cd-8ae3-1987d4f1b3b5","CFAR-Based Interference Mitigation for FMCW Automotive Radar Systems","Wang, J. (TU Delft Microwave Sensing, Signals & Systems)","","2022","In this paper, constant false alarm rate (CFAR) detector-based approaches are proposed for interference mitigation of Frequency modulated continuous wave (FMCW) radars. The proposed methods exploit the fact that after dechirping and low-pass filtering operations the targets' beat signals of FMCW radars are composed of exponential sinusoidal components while interferences exhibit short chirp waves within a sweep. The spectra of interferences in the time-frequency (t-f) domain are detected by employing a 1-D CFAR detector along each frequency bin and then the detected map is dilated as a mask for interference suppression. The proposed approaches are applicable to the scenarios in the presence of multiple interferences. Compared to the existing methods, the proposed methods reduce the power loss of useful signals and are very computationally efficient. Their interference mitigation performances are demonstrated through both numerical simulations and experimental results.","Beat signal; constant false alarm rate (CFAR) detector; Detectors; FMCW radar; interference mitigation; time-frequency spectrum","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Microwave Sensing, Signals & Systems","","",""
"uuid:19b6cf70-fc08-4fdd-b324-25f1815e3274","http://resolver.tudelft.nl/uuid:19b6cf70-fc08-4fdd-b324-25f1815e3274","Online Optimization of Gear Shift and Velocity for Eco-Driving using Adaptive Dynamic Programming","Li, Guoqiang (Beijing Institute of Technology); Gorges, Daniel (Technische Universität Kaiserslautern); Wang, M. (TU Delft Transport and Planning)","","2022","In this paper a learning-based optimization method for online gear shift and velocity control is presented to reduce the fuel consumption and improve the driving comfort in a car-following process. The continuous traction force and the discrete gear shift are optimized jointly to improve both the powertrain operation and the longitudinal motion. The problem is formulated as a nonlinear mixed-integer optimization problem and solved based on adaptive dynamic programming. A major difference compared to existing approaches is that the developed control method is model-free, i.e. it does not rely on vehicle models. It can address system nonlinearities and adapt to changes in engine characteristics (e.g. consumption map) during vehicle driving. The computation is efficient and enables possible real-time implementation. The proposed control method is studied for an urban driving cycle to evaluate the control performance with respect to the fuel economy and the driving comfort. Simulations indicate that the host vehicle can reduce the fuel consumption by 5.03% and 1.12% for two consumption maps in comparison to the preceding while keeping a desired inter-vehicle distance. The results further show a decrease of 1.59% and 2.32% in fuel consumption compared to a linear quadratic controller with the same gear shift schedule.","adaptive cruise control; adaptive dynamic programming; Biological system modeling; Eco-driving; Engines; Force; Fuel economy; gear shift schedule; Gears; Optimization; reinforcement learning; Vehicle dynamics; velocity optimization","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Transport and Planning","","",""
"uuid:c1053df6-a596-4e7d-adab-b2d5ffc93c38","http://resolver.tudelft.nl/uuid:c1053df6-a596-4e7d-adab-b2d5ffc93c38","An Output Bandwidth Optimized 200-Gb/s PAM-4 100-Gb/s NRZ Transmitter With 5-Tap FFE in 28-nm CMOS","Wang, Zhongkai (University of California); Choi, Minsoo (Samsung Semiconductor); Lee, Kyoungtae (University of California); Park, Kwanseo (University of California); Liu, Zhaokai (University of California); Biswas, Ayan (University of California); Han, Jaeduk (Hanyang University); Du, S. (TU Delft Electronic Instrumentation); Alon, Elad (University of California)","","2022","This article presents a 200-Gb/s pulse amplitude-modulation four-level (PAM-4) and 100-Gb/s non-return-to-zero (NRZ) transmitter (TX) in 28-nm CMOS technology. To achieve the target data rate, the output bandwidth and swing of the proposed TX are optimized by minimizing the output capacitance of the 4:1 multiplexer (MUX) and driver stage with pull-up current sources and adopting a fully reconfigurable 5-tap feed-forward equalizer (FFE). The key circuit includes a segmented 8:4 MUX and 4:1 MUX/driver, a thermal encoder and retimer, and a flexible clock distribution network. Using the layout generated with Berkeley Analog Generator (BAG), the proposed TX achieves an eye opening with >52.9-mV eye height, 0.36 UI eye width, >98% RLM, and 4.63 pJ/b at 200-Gb/s PAM-4 signaling under >6-dB channel loss at 50 GHz, demonstrating the highest data rate achieved using a planar process.","28 nm; 4:1 multiplexer (MUX); Berkeley Analog Generator (BAG); clock distribution; four-level pulse-amplitude modulation (PAM-4); pulse generator; quarter-rate; SerDes; transmitter (TX); wireline","en","journal article","","","","","","","","","","","Electronic Instrumentation","","",""
"uuid:bb71397c-3e47-4cbf-baf2-5dc10ee642f9","http://resolver.tudelft.nl/uuid:bb71397c-3e47-4cbf-baf2-5dc10ee642f9","Analysis of hydrodynamic trapping interactions during full-cycle injectionand migration of CO2 in deep saline aquifers","Wang, Y. (TU Delft Numerical Analysis); Vuik, Cornelis (TU Delft Numerical Analysis); Hajibeygi, H. (TU Delft Reservoir Engineering)","","2022","CO2 injection into deep saline aquifers has shown to be a feasible option, as for their large storage capacity under safe operational conditions. Previous studies have revealed that CO2 can be trapped in the subsurface by several mechanisms. Despite the major advances in studying these trapping mechanisms, their dynamic interactions in different periods of a full-cycle process have not been well understood; i.e., they are studied independently at their so-called ‘separate time scales of importance’. These mechanisms, however, are dynamically interconnected and influence each other even outside of their main time scale of importance. Besides, previous studies on field-scale simulations often choose grid cells which are too coarse to capture flow dynamics especially in post-injection period. To this end, we develop a comprehensive framework to analyze the flow dynamics and the associated hydrodynamic trapping process, in which the CO2 injection, migration and post-migration period are all considered in a unified manner. Through illustrative models with sufficient grid resolution, we quantify the impact of different trapping mechanisms and uncertain reservoir properties through a full-cycle process. We demonstrate that the time scale associated with each trapping mechanism indeed varies, yet their dynamic interplay needs to be considered for accurate and reliable predictions. Results reveal that residual trapping is governed by the advective transport in the injection period, and its contribution to the overall trapped amount becomes more significant in systems with lower permeability. Dissolution trapping operates under varying driving forces at different stages. In the injection period, the dissolution process is controlled by advective transport, and later enhanced by the gravity-induced convection in the post-injection period. Such convective transport diminishes the contribution from residual trapping. Our study sheds light on the impact of the coupled reservoir and fluid time-dependent interactions in estimation of the securely trapped CO2 in saline aquifers.","Compositional simulation; Geologic carbon storage; Multiphase flow in porous media; Multiphysics interaction","en","journal article","","","","","","","","","","","Numerical Analysis","","",""
"uuid:26a551cd-6229-4dc3-9ffc-8ceb8410962b","http://resolver.tudelft.nl/uuid:26a551cd-6229-4dc3-9ffc-8ceb8410962b","CO2 hydrogenation to methanol over Cd4/TiO2 catalyst: Insight into multifunctional interface","Li, G. (Wageningen University & Research); Meeprasert, J. (TU Delft ChemE/Inorganic Systems Engineering); Wang, J. (Chinese Academy of Sciences); Li, C. (Chinese Academy of Sciences); Pidko, E.A. (TU Delft ChemE/Inorganic Systems Engineering)","","2022","Supported metal catalysts have shown to be efficient for CO 2 conversion due to their multifunctionality and high stability. Herein, we have combined density functional theory calculations with microkinetic modeling to investigate the catalytic reaction mechanisms of CO 2 hydrogenation to CH 3OH over a recently reported catalyst of Cd 4/TiO 2. Calculations reveal that the metal-oxide interface is the active center for CO 2 hydrogenation and methanol formation via the formate pathway dominates over the reverse water-gas shift (RWGS) pathway. Microkinetic modeling demonstrated that formate species on the surface of Cd 4/TiO 2 is the relevant intermediate for the production of CH 3OH, and CH 2O # formation is the rate-determining step. These findings demonstrate the crucial role of the Cd-TiO 2 interface for controlling the CO 2 reduction reactivity and CH 3OH selectivity.","CO2; hydrogenation; CH3OH; Cd4/TiO2; multifunctional interface","en","journal article","","","","","","","","","","","ChemE/Inorganic Systems Engineering","","",""
"uuid:4d78313f-452a-4986-9ea0-9f19517e4cfe","http://resolver.tudelft.nl/uuid:4d78313f-452a-4986-9ea0-9f19517e4cfe","A Carrier-based Two-Phase-Clamped DPWM Strategy With Zero-Sequence Voltage Injection for Three-Phase Quasi-Two-Stage Buck-Type Rectifiers","Xu, J. (Shanghai Jiao Tong University); Soeiro, Thiago B. (TU Delft DC systems, Energy conversion & Storage; TU Delft Electrical Sustainable Energy); Wu, Y. (TU Delft DC systems, Energy conversion & Storage); Gao, Fei (Shanghai Jiao Tong University); Wang, Y. (TU Delft Statistics; Shanghai Jiao Tong University); Tang, Houjun (Shanghai Jiao Tong University); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2022","A three-phase buck-type rectifier features a step-down ac-dc conversion function, which is considered as a prominent solution for electric vehicle chargers and telecommunication systems integrated to the grid above 380 V line to line. However, traditional solutions for those applications employ cascaded architectures with an ac-dc boost-type stage and a dc-dc buck-type stage, which may suffer from high switching losses and large dc-link capacitor volume. To relieve this issue, a straightforward carrier-based two-phase-clamped discontinuous pulsewidth modulation (DPWM) strategy with generalized zero-sequence voltage injection is proposed in this article for the commonly employed cascaded circuit. This method can stop the switching actions in the front-end stage during two-third of the grid period, which can yield to the best switching loss reduction. The operations of the front- and back-end converter stages become highly coupled to each other, which reduces the size requirement of the capacitor in the dc link. Therefore, the equivalent circuit behaves as a quasi-two-stage buck-type rectifier allowing an enhancement of the system power density by improving power conversion efficiency and by reducing the volume of passive components and heat sink. The proposed carrier-based two-phase-clamped DPWM strategy is described, analyzed, validated, and compared with different pulsewidth modulation methods on PLECS-based simulation and a 5-kW prototype.","buck-type rectifier; Capacitors; Carrier-based; discontinuous pulsewidth modulation (DPWM); Phase modulation; Pulse width modulation; Switches; Switching loss; Voltage; Voltage control; zero-sequence voltage injection","en","journal article","","","","","","","","","","Electrical Sustainable Energy","DC systems, Energy conversion & Storage","","",""
"uuid:85b1255b-b644-4f3b-b88c-43eb7729bc0e","http://resolver.tudelft.nl/uuid:85b1255b-b644-4f3b-b88c-43eb7729bc0e","Event-triggered intelligent critic control with input constraints applied to a nonlinear aeroelastic system","Sun, B. (TU Delft Control & Simulation); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics); van Kampen, E. (TU Delft Control & Simulation)","","2022","In this paper, we establish an event-triggered intelligent control scheme with a single critic network, to cope with the optimal stabilization problem of nonlinear aeroelastic systems. The main contribution lies in the design of a novel triggering condition with input constraints, avoiding the Lipschitz assumption on the inverse hyperbolic tangent function. Based on an improved weight updating criterion that eliminates the requirement of initial admissible control, the control law is obtained approximately by online training of a single critic network. The Lyapunov stability and the Zeno phenomenon of the closed-loop system are analysed. The feasibility of the established algorithm is verified by applying it to an optimal stabilization task of a nonlinear aeroelastic system. The results reveal that the developed approach can handle input-constrained optimal control problems, with performance comparable to the time-based method that updates control inputs at each instant, while reducing the computational and communication's load.","Adaptive dynamic programming; Artificial neural network; Event-triggered control; Input constraints; Nonlinear aeroelastic system","en","journal article","","","","","","","","","","","Control & Simulation","","",""
"uuid:4f3ad93c-f134-4a63-870c-53cb7da06ff5","http://resolver.tudelft.nl/uuid:4f3ad93c-f134-4a63-870c-53cb7da06ff5","Fuzzy Adaptive Constrained Consensus Tracking of High-Order Multi-agent Networks: A New Event-Triggered Mechanism","Wang, Ning (Air Force Engineering University China); Wang, Ying (Air Force Engineering University China); Wen, Guanghui (Southeast University); Lv, Maolong (TU Delft Team Bart De Schutter; Air Force Engineering University China); Zhang, Fan (Sun Yat-sen University)","","2022","This article aims to realize event-triggered constrained consensus tracking for high-order nonlinear multiagent networks subject to full-state constraints. The main challenge of achieving such goals lies in the fact that the standard designs [e.g., backstepping, event-triggered control, and barrier Lyapunov functions (BLFs)] successfully developed for low-order dynamics fail to work for high-order dynamics. To tackle these issues, a novel high-order event-triggered mechanism is devised to update the actual control input, lowering the communication and computation burden. More precisely, compared with the conventional event-triggered mechanism, not only the amplitudes of control signals and a fixed threshold are considered but a monotonically decreasing function is introduced to allow a relatively big threshold, while guaranteeing consensus tracking error to be small. Then, a high-order tan-type BLF working for both constrained and unconstrained scenarios is incorporated into the distributed adding-one-power-integrator design for the purpose of confining full states within some compact sets all the time. A finite-time convergent differentiator (FTCD) is introduced to circumvent the ``explosion of complexity.'' The consensus tracking error is shown to eventually converge to a residual set whose size can be adjusted as small as desired through choosing appropriate design parameters. Comparative simulations have been conducted to highlight the superiorities of the developed scheme.","Backstepping; Event-triggered control (ETC); full-state constraints; high-order multiagent networks; Laplace equations; Lyapunov methods; Navigation; Standards; Task analysis; Upper bound","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Team Bart De Schutter","","",""
"uuid:3a54439f-2491-46b5-9b12-c751c44dc957","http://resolver.tudelft.nl/uuid:3a54439f-2491-46b5-9b12-c751c44dc957","Remediation potential of agricultural organic micropollutants in in-situ techniques: A review","Bai, Ying (Nanjing Hydraulic Research Institute); Wang, Zongzhi (Nanjing Hydraulic Research Institute); van der Hoek, J.P. (TU Delft Sanitary Engineering; Strategic Centre)","","2022","Agricultural activities can be important source of organic pollution. In agricultural intensive areas, organic chemicals have a high possibility of entering the water cycle, which could pose a potential risk to human health. Low-cost and high efficiency in-situ techniques instead of energy and money consuming ones to control agricultural organic micropollutants (Agro-OMPs) in aquatic system are extremely needed. In this paper, emerging Agro-OMPs were discussed focusing on their occurrence, pathways and risks. The mechanisms, dominant parameters and effectiveness of riverbank filtration, riparian buffer zone, constructed wetland and permeable reactive barriers for removing these pollutants are presented and discussed. Ecological succession in Riverbank Filtration (RBF) system is worth noticing for its stability maintenance. Riparian buffer zone (RBZ) should be explored more focusing on flexibility improvement and construction standardization. Constructed wetland (CW) is quite efficient on antibiotic resistance genes (ARGs) attenuation, but the risk of ARGs propagation still exist. Besides, more innovations should be made on combination, field-scale application and long-term evaluation of in-situ remediation techniques, which will provide references for agricultural water management and water quality improvement.","Agricultural organic micropollutants; Constructed wetland; remediation; Permeable reactive barriers; Riverbank filtration; Riparian buffer zone","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-06-09","","","Sanitary Engineering","","",""
"uuid:27c5042f-1564-40ba-a87c-63c971eea949","http://resolver.tudelft.nl/uuid:27c5042f-1564-40ba-a87c-63c971eea949","Object Detection and Person Tracking in CathLab with Automatically Calibrated Cameras","Jiang, Y. (Student TU Delft); Dai, R. (Student TU Delft); Zeng, J. (Student TU Delft); Butler, R.M. (TU Delft Medical Instruments & Bio-Inspired Technology); Vijfvinkel, T.S. (TU Delft Medical Instruments & Bio-Inspired Technology); Wang, Y. (TU Delft Signal Processing Systems); van den Dobbelsteen, J.J. (TU Delft Medical Instruments & Bio-Inspired Technology); van der Elst, M. (TU Delft Support Biomechanical Engineering); Dauwels, J.H.G. (TU Delft Signal Processing Systems)","Louveaux, Jérôme (editor); Quitin, François (editor)","2022","Workflow analysis is a young research field that has been gaining traction in recent years. Work in this field aims to improve the efficiency and safety in operating rooms by analysing surgical processes and providing feedback or support, where observations are made and evaluated by algorithms rather than human experts. For our study, we mount five cameras from different angles in a Catheterization Laboratory (CathLab) to observe and analyse Cardiac Angiogram procedures. To automate the classification of workflow and personnel activities, we propose a pipeline that first automates the camera calibration of the 5-camera network then detect locations of medical equipment and track personnel activities...","","en","conference paper","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:e5d1029d-9151-4be5-93e0-68557186d90a","http://resolver.tudelft.nl/uuid:e5d1029d-9151-4be5-93e0-68557186d90a","Embedded AI Enabled Air-Writing for a Post-COVID World: Extended Abstract","Goedemondt, K.S. (Student TU Delft); Yang, J. (TU Delft Web Information Systems); Wang, Q. (TU Delft Embedded Systems)","Louveaux, Jérôme (editor); Quitin, François (editor)","2022","Touchscreens and buttons had became a medium for virus transmission during the COVID-19 pandemic. We have seen in our daily life that people use tissues and keys to press buttons inside elevators, on public screens, etc. In the post- COVID world, touch-free interaction with public touchscreens and buttons may become more popular. Motivated by the rise of visible light communication and sensing, we design a real-time embedded system to enable touch-free fingertip writing of the digits 0–9 with only ambient light and simple photodiodes. We propose an embedded deep learning model to learn the spatial and temporal patterns in the dynamic shadow for air-writing digits recognition. The model is devised with a lightweight convolutional architecture such that it can run on a resource-limited device. We evaluate our model using the LightDigit dataset [1] and report the results in terms of accuracy and inference time.","tensors; tensor-train; Kalman filter; SVM; seizure; epilepsy; detection","en","conference paper","","","","","","","","","","","Web Information Systems","","",""
"uuid:7db95ec2-6ff6-464b-af18-545a218d0a16","http://resolver.tudelft.nl/uuid:7db95ec2-6ff6-464b-af18-545a218d0a16","Built Environment Impacts on Rural Residents’ Daily Travel Satisfaction","Li, Haimei (Chengdu University of Technology); Zhang, Yuting (Chengdu University of Technology; Southwest Jiaotong University); Ao, Yibin (Chengdu University of Technology); Wang, Yan (Sichuan College of Architectural Technology); Wang, T. (TU Delft Design & Construction Management); Chen, Yunfeng (Purdue University)","","2022","The rapid urbanization in China urges scholars to investigate the impacts of built environment on the level of travel satisfaction of rural residents to improve their quality of life and make planning exercises more human-centric. This study samples six villages out of the 25 top rural areas in Chengdu, Sichuan, China, as the research object and constructs a structural equation model to explore the direct and indirect impacts of the built environment on daily travel satisfaction of rural residents. The research finds that building density (0.609), road density (0.569), the number of accessible markets (0.314), and private car ownership (0.02) have significant positive impacts on travel satisfaction. Public transport (−0.063) has a direct negative impact on travel satisfaction. Consequently, in order to further improve travel satisfaction, construction departments and rural planners should improve the building and road densities of new rural areas and increase the number of accessible markets. The convenience of rural public transport services also needs improvement.","travel preference; travel satisfaction; rural China; travel mode; built environment","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:f52fd38d-aae3-405a-a8e6-224b1b558863","http://resolver.tudelft.nl/uuid:f52fd38d-aae3-405a-a8e6-224b1b558863","Image Search Engine by Deep Neural Networks","Yao, Y. (Student TU Delft); Zhang, Q. (Student TU Delft); HU, Y. (Student TU Delft); Meo, C. (TU Delft Signal Processing Systems); Wang, Y. (TU Delft Signal Processing Systems); Nanetti, Andrea (Nanyang Technological University); Dauwels, J.H.G. (TU Delft Signal Processing Systems)","Louveaux, Jérôme (editor); Quitin, François (editor)","2022","We typically search for images by keywords, e.g., when looking for images of apples, we would enter the word “apple” as query. However, there are limitations. For example, if users input keywords in a specific language, then they may miss results labeled in other languages. Moreover, users may have an image of the object they want to obtain more information about, e.g., a landmark, but they may not know the name of it. In such scenario, word-based search is not adequate, while imagebased search would be ideally suited. These needs drive us to develop a purely content-based image search engine, meaning that users can search images with an image as query. Motivated by this use case with numerous applications, in this paper we propose and validate an image query based search engine...","","en","conference paper","","","","","","","","","","","Signal Processing Systems","","",""
"uuid:f406f1a4-c78c-47ad-9bf3-07c597ef8856","http://resolver.tudelft.nl/uuid:f406f1a4-c78c-47ad-9bf3-07c597ef8856","Extreme Precipitation Nowcasting using Deep Generative Models","Bi, H. (Student TU Delft); Kyryliuk, M.S. (Student TU Delft); Wang, Z. (Student TU Delft); Meo, C. (TU Delft Signal Processing Systems); Wang, Y. (TU Delft Signal Processing Systems); Imhoff, Ruben (Deltares); Uijlenhoet, R. (TU Delft Water Resources); Dauwels, J.H.G. (TU Delft Signal Processing Systems)","Louveaux, Jérôme (editor); Quitin, François (editor)","2022","Extreme precipitation usually leads to substantial impacts. Floods in the Netherlands, Belgium and Germany in the summer of 2021 have caused loss of lives, destruction of infrastructures, and long-term effect on economics. To avoid such disasters, it is important to develop a reliable and accurate method to predict heavy rain.","","en","conference paper","","","","","","","","","","","Signal Processing Systems","","",""
"uuid:6f466522-97e4-48ad-ba12-38fdff9d0b23","http://resolver.tudelft.nl/uuid:6f466522-97e4-48ad-ba12-38fdff9d0b23","Influence of clustering coefficient on network embedding in link prediction","Fernández Robledo, O. (TU Delft Multimedia Computing); Zhan, X. (TU Delft Multimedia Computing; Hangzhou Normal University); Hanjalic, A. (TU Delft Intelligent Systems); Wang, H. (TU Delft Multimedia Computing)","","2022","Multiple network embedding algorithms have been proposed to perform the prediction of missing or future links in complex networks. However, we lack the understanding of how network topology affects their performance, or which algorithms are more likely to perform better given the topological properties of the network. In this paper, we investigate how the clustering coefficient of a network, i.e., the probability that the neighbours of a node are also connected, affects network embedding algorithms’ performance in link prediction, in terms of the AUC (area under the ROC curve). We evaluate classic embedding algorithms, i.e., Matrix Factorisation, Laplacian Eigenmaps and node2vec, in both synthetic networks and (rewired) real-world networks with variable clustering coefficient. Specifically, a rewiring algorithm is applied to each real-world network to change the clustering coefficient while keeping key network properties. We find that a higher clustering coefficient tends to lead to a higher AUC in link prediction, except for Matrix Factorisation, which is not sensitive to the change of clustering coefficient. To understand such influence of the clustering coefficient, we (1) explore the relation between the link rating (probability that a node pair is the missing link) derived from the aforementioned algorithms and the number of common neighbours of the node pair, and (2) evaluate these embedding algorithms’ ability to reconstruct the original training (sub)network. All the network embedding algorithms that we tested tend to assign higher likelihood of connection to node pairs that share an intermediate or high number of common neighbours, independently of the clustering coefficient of the training network. Then, the predicted networks will have more triangles, thus a higher clustering coefficient. As the clustering coefficient increases, all the algorithms but Matrix Factorisation could also better reconstruct the training network. These two observations may partially explain why increasing the clustering coefficient improves the prediction performance.","Clustering coefficient; Link prediction; Network embedding; OA-Fund TU Delft","en","journal article","","","","","","","","","","Intelligent Systems","Multimedia Computing","","",""
"uuid:a70e80dd-0555-4117-8fb3-bb0186f8dd8a","http://resolver.tudelft.nl/uuid:a70e80dd-0555-4117-8fb3-bb0186f8dd8a","Intelligent Data Fusion for Anomaly Detection in Dutch Railway Catenary Condition Monitoring","Wang, H. (TU Delft Railway Engineering); Hendriks, J.M. (TU Delft Railway Engineering); Dollevoet, R.P.B.J. (TU Delft Railway Engineering); Zoeteman, Arjen (ProRail); Nunez, Alfredo (TU Delft Railway Engineering)","","2022","Aiming to handle the increasing variety and volume of railway infrastructure monitoring data, this paper explores the use of intelligent data fusion methods for automatic anomaly detection of railway catenaries. Three classical data dimensionality reduction methods, namely the principal component analysis (PCA), the autoencoder neural network, and the t-distributed stochastic neighbor embedding (t-SNE) are adopted for the data fusion of catenary monitoring data. Then, anomaly detection can be achieved using new features that are automatically extracted from the original data, which requires no prior knowledge of the data or catenary conditions. A case study using data measured from the Dutch railway is presented to compare the performance of the three methods. Six types of catenary monitoring data, including pantograph-catenary contact force, pantograph-catenary friction force, contact wire thickness, contact wire height and stagger, are used in the presented case study. It is demonstrated that both PCA and autoencoder can detect anomalies from catenary monitoring data, while t-SNE shows little indication of such ability. Further, the autoencoder outperforms PCA in distinguishing anomalies in the case study, likely owing to its superiority in analysing data with nonlinearity. Overall, autoencoder is a promising technique for automating the anomaly detection of railway catenaries. The detection results can provide indicators for failure prediction and maintenance decision making.","railway catenary; data fusion; anomaly detection; condition monitoring","en","conference paper","","","","","","","","","","","Railway Engineering","","",""
"uuid:5e5022f8-2ee1-4803-9716-37d0ca5c399a","http://resolver.tudelft.nl/uuid:5e5022f8-2ee1-4803-9716-37d0ca5c399a","Electron-Irradiation-Induced Degradation of Transfer Characteristics in Super-Junction VDMOSFET","Jiang, Jing (Fudan University); Wang, S. (TU Delft Bio-Electronics; Southern University of Science and Technology); Liu, X. (TU Delft Interactive Intelligence; Southern University of Science and Technology); Liu, Jianhui (Sky Chip Interconnection Technology Co); Li, Jun (Sky Chip Interconnection Technology Co); Zhou, Dexiang (Sky Chip Interconnection Technology Co); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Ye, H. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology; Chongqing University); Tan, C. (TU Delft Electronic Components, Technology and Materials; Chongqing University)","","2022","High electric-field stress is an effective solution to the recovery of irradiated devices. In this paper, the dependence of the recovery level on the magnitude of gate voltage and duration is investigated. Compared with the scheme of high gate-bias voltage with a short stress time, the transfer characteristics are significantly recovered by applying a low electric field with a long duration. When the electric field and stress time are up to a certain value, the threshold voltage almost approaches the limitation, which is less than that before irradiation. Meanwhile, the effect of temperature on the recovery of the irradiated devices is also demonstrated. The result indicates that a high temperature of 175 °C used for the irradiated devices’ annealing does not play a role in promoting the recovery of transfer characteristics. In addition, to obtain a deep-level understanding of threshold degradation, the first-principles calculations of three Si/SiO2 interfaces are performed. It is found that new electronic states can be clearly observed in the conduction bans and valence bands after the Si-H/-OH bonds are broken by electron irradiation. However, their distribution depends on the selection of the passivation scheme. Ultimately, it can be observed that the threshold voltage linearly decreases with the increase in interface charge density. These results can provide helpful guidance in the deep interpretation of threshold degradation and the recovery of the irradiated super-junction devices.","electron irradiation; transfer characteristics; degradation; Si/SiO2 interface; first-principles calculation; interface charge density; threshold variation","en","journal article","","","","","","","","","","","Bio-Electronics","","",""
"uuid:3f28f42e-96fa-4d82-bdef-883ad5e0ab89","http://resolver.tudelft.nl/uuid:3f28f42e-96fa-4d82-bdef-883ad5e0ab89","Simulation and Verification or Cu@Ag Core-shell Sintered Paste for Power Semiconductor Die-attach Applications","Wang, Xinyue (Fudan University); Zeng, Zejun (Fudan University); Zhang, Jing (Heraeus Materials Technology); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Liu, Pan (Fudan University)","O'Conner, L. (editor)","2022","With the increasing application of wide bandgap materials such as silicon carbide and gallium nitride in power devices, the working temperature of power devices has been pushed further. Therefore, it brings higher requirements for packaging materials. Sintered silver is a widely accepted chip connection material. However, silver suffers from high prices and electromigration. Therefore, a novel sintered material based on silver-copper core-shell structured particles raises the attention of researchers to solve this deficiency. To accelerate the development of new materials and their related processes, a four-sphere model of the silver-coated copper structure is established in this paper. The mathematical relationship between the porosity and thermal conductivity of sintered body and the actual sintering process was preliminarily established through the calculation based on a series of FEM simulations. The model was further validated through experiments. The modeling method and conclusion are utilized for future process adjustment, which is of great significance to accelerate the development, application, and reliability of new packaging materials.","die-attach material; power electronic packaging; simulation; Cu@Ag particles","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Components, Technology and Materials","","",""
"uuid:1b86b152-df14-4874-8bc8-1b09fc3ae0b8","http://resolver.tudelft.nl/uuid:1b86b152-df14-4874-8bc8-1b09fc3ae0b8","Adaptive Nonlinear Incremental Flight Control for Systems with Unknown Control Effectiveness","Chang, J. (TU Delft Aerospace Structures & Computational Mechanics); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics)","","2022","This article exposes that although some sensor-based nonlinear fault-tolerant control frameworks including incremental nonlinear dynamic inversion control can passively resist a wide range of actuator faults and structural damage without requiring an accurate model of the dynamic system, their stability heavily relies on a sufficient condition, which is unfortunately violated if the control direction is unknown. Consequently, it is proved in this article that no matter, which perturbation compensation technique (adaptive, disturbance observer, sliding-mode) is implemented, none of the existing nonlinear incremental control methods can guarantee closed-loop stability. Therefore, this article proposes a Nussbaum function-based adaptive incremental control framework for nonlinear dynamic systems with partially known (control direction is unknown) or even completely unknown control effectiveness. Its effectiveness is proved in the Lyapunov sense and is also verified via numerical simulations of an aircraft attitude tracking problem in the presence of sensing errors, parametric model uncertainties, structural damage, actuator faults, as well as inversed and unknown control effectiveness.","Adaptive control; Adaptive Control; Aerospace control; Fault-Tolerant Flight Control; Incremental Control; MIMO communication; Numerical stability; Perturbation methods; Stability criteria; Thermal stability; Unknown Control Direction","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-03-10","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:11dbd512-08cc-489e-b06b-46820d22590f","http://resolver.tudelft.nl/uuid:11dbd512-08cc-489e-b06b-46820d22590f","Influences of the Built Environment on Rural School Children’s Travel Mode Choice: The Case of Chengdu","Li, Haimei (Chengdu University of Technology); Han, Li (Chengdu University of Technology); Ao, Yibin (Chengdu University of Technology); Wang, Yan (Sichuan College of Architectural Technology); Wang, T. (TU Delft Design & Construction Management)","","2022","Since the reform and opening up of China, the rural built environment has changed dramatically. There is a need to understand how such changes have impacted rural children’s school travel mode choice to design the built environment and plan schools accordingly. This paper combines field measurement methods and questionnaires to obtain data on rural children’s school travel behavior and uses the multinomial logit (MNL) model to investigate the impacting factors. The results show the following insights: Age has a significant positive impact on children’s choice of bicycles and buses. The improvements in road layout and facility conditions are significantly and positively associated with children’s choice of electric bicycles for school. There is a significant positive correlation between a good and safe public environment and children’s choice of cycling. Furthermore, distance from home to school has a significant impact on the choice of children’s school travel mode: the greater the distance to school, the higher the probability that children will choose motorized modes of travel such as buses and private cars. This study provides empirical data and evidence in designing rural transport systems for school children based on their preferences concerning built environment factors.","urbanization; rural built environment; school travel; the multinomial logit model","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:bbfd5115-db64-4621-b580-8ff4715ce167","http://resolver.tudelft.nl/uuid:bbfd5115-db64-4621-b580-8ff4715ce167","Building Information Modeling Learning Behavior of AEC Undergraduate Students in China","Peng, Panyu (Chengdu University of Technology); Ao, Yibin (Chengdu University of Technology); Li, Mingyang (Chengdu University of Technology); Wang, Yan (Sichuan College of Architectural Technology); Wang, T. (TU Delft Design & Construction Management); Bahmani, Homa (Chengdu University of Technology)","","2022","With the popularization and application of Building Information Modeling (BIM), the demand for BIM technical talents in the construction industry is increasing. Exploring college students’ BIM technical learning behavior is of great practical significance to improve education activities. Based on the Unified Theory of Acceptance and Use of Technology (UTAUT), this research adds learning attitude variables to construct a theoretical model of influencing factors of college students’ BIM technology learning behavior. Chinese undergraduate students were asked to complete online questionnaires through peer-to-peer contact with sample colleges and universities. Finally, 1090 valid questionnaires were obtained. The students were sampled from research-oriented, applied research-oriented, application-oriented, and private research-oriented universities in seven regions of China: northeast, north, east, south, central, northwest, and southwest. The structural equation model was used to analyze the sampling data. The results indicate that college students’ BIM learning attitude, performance expectations, and social influence positively and directly impact their learning intention, which indirectly impacts their learning behavior. At the same time, promoting factors and learning intention demonstrate a significant positive and direct impact on learning behavior. Therefore, the following suggestions have been put forward to enhance college students’ learning motivation for BIM technology: increase the popularization of BIM technology in colleges and universities and improve the operation level of full-time BIM teachers. The latter enables colleges and universities to continuously and stably export qualified BIM technical talents to society and the market, resulting in a continuous industry development cycle","learning behavior; BIM; influencing factors; UTAUT theoretical model; structural equation modeling","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:04f563e0-5093-4bf4-887b-5ed07c0c9b3a","http://resolver.tudelft.nl/uuid:04f563e0-5093-4bf4-887b-5ed07c0c9b3a","Determinants of villagers’ satisfaction with post-disaster reconstruction: Evidence from surveys ten years after the Wenchuan earthquake","Ao, Yibin (Chengdu University of Technology); Zhong, Jinglin (Chengdu University of Technology); Zhang, Zijun (Chengdu University of Technology); Han, Lili (Chengdu University of Technology); Wang, Yan (Sichuan College of Architectural Technology); Chen, Yunfeng (Purdue University); Wang, T. (TU Delft Design & Construction Management)","","2022","Residents’ satisfaction with post-disaster reconstruction in earthquake-stricken areas directly affects their quality of life, which cannot be ignored in post-disaster reconstruction. More than 10 years after the Wenchuan earthquake, we took ten randomly selected villages in the five areas hardest-hit by the Wenchuan earthquake as research objects and obtained 483 valid completed questionnaires. The villagers were randomly sampled and descriptive statistical analysis, factor analysis, and ordered logistic regression were used to explore the factors and relationships influencing villagers’ satisfaction with post-disaster reconstruction in Wenchuan earthquake-stricken areas. The results show that: 1) the more rural residents know about the post-disaster reconstruction, the greater their level of satisfaction; 2) the more the annual income of families increases after resettlement, the greater the satisfaction of rural residents with the post-disaster reconstruction; 3) six public factors, namely the village committee acts as, housing construction quality, public service, policy of benefiting farmers, cultural environment, and hardware environment, all significantly positively affect residents’ overall satisfaction with post-earthquake reconstruction. This study thus enriches the theory of residents’ satisfaction studies and the practice of post-earthquake reconstruction.","earthquake-stricken area; post-disaster reconstruction; satisfaction analysis; factorial analysis; ordered logistic regression","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:ccc9e53c-1e3c-4f58-ba4a-09b8668b7f78","http://resolver.tudelft.nl/uuid:ccc9e53c-1e3c-4f58-ba4a-09b8668b7f78","Safety-oriented planning of expressway truck service areas based on driver demand","Ding, Wenlong (Tongji University); Wang, Y. (TU Delft Civil Engineering & Geosciences); Chu, Pengzi (Tongji University); Chen, Feng (Tongji University); Song, Yongchao (Chongqing Jiaotong University); Zhang, Ning (University of California); Lin, Dong (University of Aberdeen)","","2022","The rapid development of the economy has promoted the growth of freight transportation. The truck service areas on expressways, as the main places for truck drivers to rest, play an important role in ensuring the driving safety of trucks. If these service areas are constructed densely or provide a plentiful supply of parking areas, they are costly to construct. However, if the distance between two adjacent truck service areas is very large or the number of truck parking spaces in service areas is small, the supply will fail to meet the parking needs of truck drivers. In this situation, the continuous working time of truck drivers will be longer, and this is likely to cause driver fatigue and even traffic accidents. To address these issues, this paper established a non-linear optimization model for truck service area planning of expressways to optimize truck driving safety. An improved genetic algorithm is proposed to solve the model. A case study of a 215.5-kilometers-length section of the Guang-Kun expressway in China was used to demonstrate the effectiveness of the model and algorithm. As validated by this specific case, the proposed model and solution algorithm can provide an optimal plan for the layout of truck service areas that meet the parking needs of truck drivers while minimizing the service loss rate. The research results of this paper can contribute to the construction of truck service areas and the parking management of trucks on expressways.","expressway driving safety; improved genetic algorithm; non-linear optimization model; service loss rate; truck service areas","en","journal article","","","","","","","","","Civil Engineering & Geosciences","","","","",""
"uuid:31a8a4d3-652f-464d-bda5-d9b5de2e9be2","http://resolver.tudelft.nl/uuid:31a8a4d3-652f-464d-bda5-d9b5de2e9be2","Platform Development of BIM-Based Fire Safety Management System Considering the Construction Site","Yang, Yapin (Hunan University); Sun, Ying (Concordia University); Chen, Mingsi (Hunan University); Zhou, Yuekuan (The Hong Kong Polytechnic University; The Hong Kong University of Science and Technology); Wang, Ran (Hunan University); Liu, Zhengxuan (TU Delft Design & Construction Management; Hunan University)","","2022","Fire at a construction site usually results in serious accidents. Therefore, fire management at the construction site is critical to decreasing possible accidents. However, conventional fire safety management can be problematic in many aspects, such as visualization, multi-stage alarm systems, and dynamic escape route optimization. To solve these issues, this paper develops a platform for a BIM-based fire safety management system that considers the construction site. The developed platform contains four subsystems: a remote monitoring subsystem, a fire visualization subsystem, a multi-stage fire alarm subsystem, and an escape route optimization subsystem. It detects the fire hazard in the early stage of the fire by the remote monitoring subsystem and transmits this information to the fire visualization subsystem for displaying. Furthermore, the multi-stage fire alarm subsystem sends warnings or alarms based on the fire’s severity. Moreover, the escape route optimization subsystem dynamically optimizes the evacuation routes by considering the actual number of people at the construction site and the potential crowding as people pass through the escapeway. Results show that this system can provide informative and on-time fire protection measures to different participants at the construction site. This study can also serve as a solution to improve fire safety management at the construction site.","construction site; fire safety management; BIM technology; escape route optimization; visualization","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:b011d7af-3b92-4511-bca2-80d9d3bc3fd3","http://resolver.tudelft.nl/uuid:b011d7af-3b92-4511-bca2-80d9d3bc3fd3","A Scoping Literature Review of Rural Institutional Elder Care","Li, Mingyang (Chengdu University of Technology); Ao, Yibin (Chengdu University of Technology); Deng, Shulin (Chengdu University of Technology); Peng, Panyu (Chengdu University of Technology); Chen, Shuangzhou (University of Hong Kong); Wang, T. (TU Delft Design & Construction Management); Martek, Igor (Deakin University); Bahmani, Homa (Chengdu University of Technology)","","2022","Under circumstances of pervasive global aging combined with weakened traditional family elder care, an incremental demand for institutional elder care is generated. This has led to a surge in research regarding institutional elder care. Rural residents’ institutional elder care is receiving more attention as a major theme in social sciences and humanities research. Based on 94 articles related to rural institutional elder care, this study identified the most influential articles, journals and countries in rural institutional elder care research since 1995. This was done using science mapping methods through a three-step workflow consisting of bibliometric retrieval, scoping analysis and qualitative discussion. Keywords revealed five research mainstreams in this field: (1) the cognition and mental state of aged populations, (2) the nursing quality and service supply of aged care institutions, (3) the aged care management systems’ establishment and improvements, (4) the risk factors of admission and discharge of aged care institutions, and (5) deathbed matters regarding the aged population. A qualitative discussion is also provided for 39 urban and rural comparative research papers and 55 pure rural research papers, summarizing the current research progress status regarding institutional elder care systems in rural areas. Gaps within existing research are also identified to indicate future research trends (such as the multi-dimensional and in-depth comparative research on institutional elder care, new rural institutional elder care model and technology, and correlative policy planning and development), which provides a multi-disciplinary guide for future research.","rural areas; institutional elder care; science mapping; scoping analysis; literature review","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:c6e33c73-1eb3-4953-8150-e6b001140ba2","http://resolver.tudelft.nl/uuid:c6e33c73-1eb3-4953-8150-e6b001140ba2","Scenario Analysis for Resilient Urban Green Infrastructure","Li, Bo (Central South University); Wang, Yue (Central South University); Wang, T. (TU Delft Design & Construction Management); He, Xiaoman (Central South University); Kazak, Jan K. (Wroclaw University of Environmental and Life Sciences)","","2022","With the advancement of urbanization, the stress on the green infrastructure around the urban agglomeration has intensified, which causes severe ecological problems. The uncertainty of urban growth makes it difficult to achieve effective protection only by setting protection red lines and other rigid measures. It is of practical significance to optimize the resilience of the stressed green infrastructure. To this end, we explore a scenario simulation analysis method for the resilience management of green infrastructure under stress. This research applies artificial neural network cellular automata to simulate the impacts of the Chang-Zhu-Tan urban agglomeration expansion on the green infrastructure in 2030 in three scenarios: no planning control, urban planning control, and ecological protection planning control. Based on the analysis, we identify four green infrastructure areas under stress and formulate resilience management measures, respectively. The results show that: (1) The distribution pattern of green infrastructure under stress is different in three scenarios. Even in the scenario of ecological protection planning and control, urban growth can easily break through the ecological protection boundary; (2) Residential, industrial, and traffic facility land are the main types of urban land causing green infrastructure stress, while forest, shrub, and wetland are the main types of the stressed green infrastructure; (3) Efficient protection of green infrastructure and the management of the urban growth boundary should be promoted by resilient management measures such as urban planning adjustment, regulatory detailed planning, development strength control and setting up the ecological protection facilities for the stressed green infrastructure areas of the planning scenarios and the no-planning control scenarios, for the areas to be occupied by urban land, and for the important ecological corridors. The results of this study provide an empirical foundation for formulating policies and the methods of this study can be applied to urban ecological planning and green infrastructure management practice in other areas as well.","green infrastructure; resilience management; biodiversity; scenario analysis; cellular automata model","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:ead36177-821d-4233-a014-71f860d662fd","http://resolver.tudelft.nl/uuid:ead36177-821d-4233-a014-71f860d662fd","Deep Deterministic Policy Gradient for High-Speed Train Trajectory Optimization","Ning, Lingbin (Beijing Jiaotong University); Zhou, Min (Beijing Jiaotong University); Hou, Zhuopu (Beijing Jiaotong University); Goverde, R.M.P. (TU Delft Transport and Planning); Wang, Fei Yue (Chinese Academy of Sciences); Dong, Hairong (Beijing Jiaotong University)","","2022","This paper proposes a novel train trajectory optimization approach for high-speed railways. We restrict our attention to single train operation scenarios with different scheduled/rescheduled running times aiming at generating optimal train recommended trajectories in real time, which can ensure punctuality and energy efficiency of train operation. A learning-based approach deep deterministic policy gradient (DDPG) is designed to generate optimal train trajectories based on the offline training from the interaction between the agent and the trajectory simulation environment. An allocating running time and selecting operation modes (ARTSOM) algorithm is proposed to improve train punctuality and give a series of discrete operation modes (full traction, cruising, coasting, full braking), and thus to produce a feasible training set for DDPG, which can speed up the training process. Numerical experiments show that an optimized speed profile can be generated by DDPG within seconds on a realistic railway line. In addition, the results demonstrate the generalization ability of trained DDPG in solving TTO problems with different running times and line conditions.","deep deterministic policy gradient; energy efficiency; High-speed railway; train trajectory optimization","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Transport and Planning","","",""
"uuid:81790001-cc3b-4de8-bd09-812b8d246714","http://resolver.tudelft.nl/uuid:81790001-cc3b-4de8-bd09-812b8d246714","4S3F Diagnostic Bayesian Network method: discussion about application and technical design","Wang, Z. (TU Delft Building Energy Epidemiology); Meijer, A. (TU Delft Building Energy Epidemiology); Itard, L.C.M. (TU Delft Building Energy Epidemiology)","","2022","In practice, automated energy performance fault diagnosis systems are seldom installed in HVAC systems. The main reason is that a specific Fault Detection and Diagnosis (FDD) setup is time-consuming and expensive because the existing methods are component-specific, not aligned with HVAC design practices, and not fully automated. 4S3F (four symptoms three faults) method, based on system engineering and Diagnostic Bayesian Networks (DBN), was proposed to decrease the gap between the design of HVAC systems for buildings and energy performance diagnosis, and proofs of concepts were tested on diverse parts of the HVAC system of one specific building. In order to test the further applicability potential of the method, it is necessary to expand these tests and to study possible problems arising in practice, like the lack of sensors installed in a specific system or practical difficulties in the construction of the 4S3F Bayesian network by HVAC or control. However, due to the small number of validations carried out on the environment, parameters, and installation process of this method still need further discussion and refinements. In this paper, we investigate how to construct the DBN for the quite generic AHU (Air Handling Unit) of a, with mechanical supply and exhaust, heating and cooling coils, and heat recovery. The paper describes the possible DBN's depending on the technical design and the measurement points. The diverse Bayesians networks are compared, and it is concluded that also, with a limited number of sensors, a diagnostic network can be set up. It is also concluded that step-by-step instructions would be needed to facilitate the work of HVAC engineers when setting up the diagnosis model.","Bayesian network; building energy performance; building energy diagnostics","en","conference paper","TU Delft OPEN Publishing","","","","","","","","","","Building Energy Epidemiology","","",""
"uuid:8cad08a5-2001-46d8-ac8b-ea3eacd18e76","http://resolver.tudelft.nl/uuid:8cad08a5-2001-46d8-ac8b-ea3eacd18e76","An Experimental Study of Wind Resistance and Power Consumption in MAVs with a Low-Speed Multi-Fan Wind System","Olejnik, D.A. (TU Delft Control & Simulation); Wang, S. (TU Delft Control & Simulation); Dupeyroux, J.J.G. (TU Delft Control & Simulation); Stroobants, S. (TU Delft Control & Simulation); Karasek, M. (TU Delft Control & Simulation); de Wagter, C. (TU Delft Control & Simulation); de Croon, G.C.H.E. (TU Delft Control & Simulation)","Pappas, George J. (editor); Kumar, Vijay (editor)","2022","This paper discusses a low-cost, open-source and open-hardware design and performance evaluation of a low-speed, multi-fan wind system dedicated to micro air vehicle (MAV) testing. In addition, a set of experiments with a flapping wing MAV and rotorcraft is presented, demonstrating the capabilities of the system and the properties of these different types of drones in response to various types of wind. We performed two sets of experiments where a MAV is flying into the wake of the fan system, gathering data about states, battery voltage and current. Firstly, we focus on steady wind conditions with wind speeds ranging from 0.5 m S-1 to 3.4 m S-1. During the second set of experiments, we introduce wind gusts, by periodically modulating the wind speed from 1.3 m S−1 to 3.4 m S−1 with wind gust oscillations of 0.5 Hz, 0.25 Hz and 0.125 Hz. The “Flapper” flapping wing MAV requires much larger pitch angles to counter wind than the “CrazyFlie” quadrotor. This is due to the Flapper's larger wing surface. In forward flight, its wings do provide extra lift, considerably reducing the power consumption. In contrast, the CrazyFlie's power consumption stays more constant for different wind speeds. The experiments with the varying wind show a quicker gust response by the CrazyFlie compared with the Flapper drone, but both their responses could be further improved. We expect that the proposed wind gust system will provide a useful tool to the community to achieve such improvements.","","en","conference paper","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Control & Simulation","","",""
"uuid:35039de1-a63c-4352-97d5-8e2a46946390","http://resolver.tudelft.nl/uuid:35039de1-a63c-4352-97d5-8e2a46946390","Battle the Wind: Improving Flight Stability of a Flapping Wing Micro Air Vehicle Under Wind Disturbance With Onboard Thermistor-Based Airflow Sensing","Wang, S. (TU Delft Control & Simulation); Olejnik, D.A. (TU Delft Control & Simulation); de Wagter, C. (TU Delft Control & Simulation); van Oudheusden, B.W. (TU Delft Aerodynamics); de Croon, G.C.H.E. (TU Delft Control & Simulation); Hamaza, S. (TU Delft Control & Simulation)","","2022","Flyers in nature equip different airflow sensing mechanisms to navigate through wind disturbances with remarkable flight stability. Embracing bio-inspiration, airflow sensing with conventional sensors has long been utilized in flight control for larger micro air vehicles (MAVs). Bio-inspired flapping wing MAVs (FWMAVs) have extremely limited power and payload, therefore implementing onboard airflow sensing has remained a challenge in spite of various attempts at miniaturized airflow sensor designs. This work characterizes the measurement performance of a lightweight off-the-shelf thermistor-based airflow sensor through comparison with a hot-wire probe. Wind tunnel tethered flight tests on a 31.3-gram FWMAV Delfly Nimble examine the onboard sensing performance at low flow speeds (up to 2 m/s), under the influence of flapping motion. This performance characterization further motivates a miniaturized re-design of the airflow sensor with over 40% size and weight reduction. The redesigned airflow sensor helps to realize the first flapping wing MAV free flight with onboard airspeed measurements, providing remarkable flight stability under wind speeds in the range of approximately 0.5 to 1.2 m/s. This embodied sensing configuration pushes the weight and power limit of miniaturized electronics for FWMAVs, providing an easy-to-integrate solution with good performance, and paving the way for more complex control of FWMAVs in dynamic conditions.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-01-16","","","Control & Simulation","","",""
"uuid:bf5c4745-4270-4304-a686-095058f5a4e6","http://resolver.tudelft.nl/uuid:bf5c4745-4270-4304-a686-095058f5a4e6","A human-centric machine learning based personalized route choice prediction in navigation systems","Sun, Bingrong (University of Virginia); Gong, Lin (University of Virginia); Shim, J. (TU Delft Transport and Planning); Jang, Kitae (Korea Advanced Institute of Science and Technology); Park, B. Brian (University of Virginia); Wang, Hongning (University of Virginia); Hu, Jia (Tongji University)","","2022","Real-world route navigation data indicate that nontrivial portion of drivers do not prefer the system-recommended best routes. Current navigation systems have simplified assumptions about drivers’ route choice preferences and do not adequately accommodate drivers’ heterogeneous route choice preferences, mainly because of: (i) difficulty in acquiring exogenous criteria (e.g., sociodemographic information) that are typically used to differentiate drivers’ preferences in behavioral modeling; and (ii) difficulty in capturing preference of individuals due to limited preference data at the individual level. To address these, this paper introduced a human-centric machine learning technique named Multi-Task Linear Classification Model Adaption (MT-LinAdapt). It can capture drivers’ common aspects of route choice preferences and yet adapts to each driver’s own preference. In addition, any evolvement of individual drivers’ preferences can be simultaneously integrated to update the common preference for further individual drivers’ preference adaptation. This paper evaluated MT-LinAdapt against two state-of-the-art route recommendation strategies including an aggregate-level and an individual-level data-based strategies, which are categorized based on the data used for modeling. With a real-world dataset containing 30,837 drivers’ navigation usage data in Daegu City, South Korea, MT-LinAdapt was compared to existing strategies for its performance at different levels of data availability, and showed at least the same performance with existing strategies when minimum preference data is available and achieves up to 7% higher prediction accuracy as more data becomes available. Higher prediction accuracies are expected to bring better user satisfaction and compliance rates which can further help with transportation system control and management strategies.","Intelligent transportation system; machine learning; personalized choice prediction; route choice; traveler information system","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Transport and Planning","","",""
"uuid:eb1573d9-d884-4b6e-90e3-84a7be313033","http://resolver.tudelft.nl/uuid:eb1573d9-d884-4b6e-90e3-84a7be313033","Digital Patient Experience: Umbrella Systematic Review","Wang, T. (TU Delft Applied Ergonomics and Design); Giunti, Guido (TU Delft Applied Ergonomics and Design; Oulu University); Melles, M. (TU Delft Applied Ergonomics and Design); Goossens, R.H.M. (TU Delft Human-Centered Design; TU Delft Applied Ergonomics and Design)","","2022","Background: The adoption and use of technology have significantly changed health care delivery. Patient experience has become a significant factor in the entire spectrum of patient-centered health care delivery. Digital health facilitates further improvement and empowerment of patient experiences. Therefore, the design of digital health is served by insights into the barriers to and facilitators of digital patient experience (PEx). Objective: This study aimed to systematically review the influencing factors and design considerations of PEx in digital health from the literature and generate design guidelines for further improvement of PEx in digital health. Methods: We performed an umbrella systematic review following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology. We searched Scopus, PubMed, and Web of Science databases. Two rounds of small random sampling (20%) were independently reviewed by 2 reviewers who evaluated the eligibility of the articles against the selection criteria. Two-round interrater reliability was assessed using the Fleiss-Cohen coefficient (k1=0.88 and k2=0.80). Thematic analysis was applied to analyze the extracted data based on a small set of a priori categories. Results: The search yielded 173 records, of which 45 (26%) were selected for data analysis. Findings and conclusions showed a great diversity; most studies presented a set of themes (19/45, 42%) or descriptive information only (16/45, 36%). The digital PEx-related influencing factors were classified into 9 categories: patient capability, patient opportunity, patient motivation, intervention technology, intervention functionality, intervention interaction design, organizational environment, physical environment, and social environment. These can have three types of impacts: positive, negative, or double edged. We captured 4 design constructs (personalization, information, navigation, and visualization) and 3 design methods (human-centered or user-centered design, co-design or participatory design, and inclusive design) as design considerations. Conclusions: We propose the following definition for digital PEx: ""Digital patient experience is the sum of all interactions affected by a patient's behavioral determinants, framed by digital technologies, and shaped by organizational culture, that influence patient perceptions across the continuum of care channeling digital health."" In this study, we constructed a design and evaluation framework that contains 4 phases-define design, define evaluation, design ideation, and design evaluation-and 9 design guidelines to help digital health designers and developers address digital PEx throughout the entire design process. Finally, our review suggests 6 directions for future digital PEx-related research.","digital health; eHealth; human-computer interaction; influencing factors; mHealth; mobile health; patient experience; telehealth; telemedicine; user experience; user-centered design; OA-Fund TU Delft","en","review","","","","","","","","","","Human-Centered Design","Applied Ergonomics and Design","","",""
"uuid:291137d4-603b-48b3-a650-530f4610de97","http://resolver.tudelft.nl/uuid:291137d4-603b-48b3-a650-530f4610de97","The Effectiveness of Master Plans: Case Studies of Biologically Active Areas in Suburban Zones","Błasik, Magdalena (Wroclaw University of Environmental and Life Sciences); Wang, T. (TU Delft Design & Construction Management); Kazak, Jan K. (Wroclaw University of Environmental and Life Sciences)","","2022","Sustainable development on a local scale requires well-functioning instruments in the spatial planning system. Any weakness in the planning system may result in forms of spatial development that are socially, environmentally or economically disadvantageous. Therefore, the aim of this study was to examine whether master plans and land development monitoring in the Polish system are effective instruments in shaping sustainable spatial development. The factor analyzed was the share of a biologically active area and four villages located near a regional city were analyzed. Data from master plans, cadaster and orthophoto maps were used in this study. Verification of land use made it possible to evaluate whether the properties meet the provisions of spatial planning documents. In each of the analyzed villages, properties that do not meet the provisions of master plans were identified. In one of the villages, more than half of the properties had a smaller share of biologically active areas than per-mitted by the local law. The research also analyzed alternative scenarios of the potential impact of the application of permanent vegetation on sealed surfaces. These results showed that using green roofs, for example, can significantly re-duce the problem of local laws being broken. The results quantitatively confirm that the provision of master plans in the Polish system are not effective tools in regulating land development.","effectiveness; master plan; spatial planning; suburban zon","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:f20e0931-1a72-4ead-8f19-298ef157822f","http://resolver.tudelft.nl/uuid:f20e0931-1a72-4ead-8f19-298ef157822f","Data-driven Methods to Predict the Burst Strength of Corroded Line Pipelines Subjected to Internal Pressure","Cai, Jie (University of Southern Denmark); Jiang, X. (TU Delft Transport Engineering and Logistics); Yang, Yazhou (National University of Defense Technology); Lodewijks, Gabriel (The University of Newcastle, Australia); Wang, Minchang (Hangzhou Silan Microelectronics Co. Ltd.)","","2022","A corrosion defect is recognized as one of the most severe phenomena for high-pressure pipelines, especially those served for a long time. Finite-element method and empirical formulas are thereby used for the strength prediction of such pipes with corrosion. However, it is time-consuming for finite-element method and there is a limited application range by using empirical formulas. In order to improve the prediction of strength, this paper investigates the burst pressure of line pipelines with a single corrosion defect subjected to internal pressure based on data-driven methods. Three supervised ML (machine learning) algorithms, including the ANN (artificial neural network), the SVM (support vector machine) and the LR (linear regression), are deployed to train models based on experimental data. Data analysis is first conducted to determine proper pipe features for training. Hyperparameter tuning to control the learning process is then performed to fit the best strength models for corroded pipelines. Among all the proposed data-driven models, the ANN model with three neural layers has the highest training accuracy, but also presents the largest variance. The SVM model provides both high training accuracy and high validation accuracy. The LR model has the best performance in terms of generalization ability. These models can be served as surrogate models by transfer learning with new coming data in future research, facilitating a sustainable and intelligent decision-making of corroded pipelines.","Burst strength; Corrosion; Data-driven method; Internal pressure; Machine learning; Pipelines","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-01-29","","","Transport Engineering and Logistics","","",""
"uuid:acd2ba81-df63-4e03-a4b9-538c0ee69ca3","http://resolver.tudelft.nl/uuid:acd2ba81-df63-4e03-a4b9-538c0ee69ca3","Safety Performance Boundary Identification of Highly Automated Vehicles: A Surrogate Model-Based Gradient Descent Searching Approach","Wang, Y. (TU Delft Transport and Planning; Tongji University); Yu, Rongjie (Tongji University); Qiu, Shuhan (Tongji University); SUN, J. (Tongji University); Farah, H. (TU Delft Transport and Planning)","","2022","Highly automated vehicles (HAVs) have been introduced to the transportation system for the purpose of providing safer mobility. Considering the expected long co-existence period of HAVs and human-driven vehicles (HDVs), the safety operation of HAVs interacting with HDVs needs to be verified. To achieve this, HAVs' Operational Design Domain (ODD) needs to be identified under the scenario-based testing framework. In this study, a novel testing framework aiming at identifying the Safety performance boundary (SPB) is proposed, which assures the coverage of safety-critical scenarios and compatible with the black-box feature of HAV control algorithm. A surrogate model was utilized to approximate the safety performance of HAV, and a gradient descent searching algorithm was employed to accelerate the search for SPB. For empirical analyses, a three-vehicle following scenario was adopted and the Intelligent Driver Model (IDM) was tested as a case study. The results show that only 4% of the total scenarios are required to establish a reliable surrogate model. And the gradient descent algorithm was able to establish the SPB by identifying 97.42% of collision scenarios and only false alarming 0.29% of non-collision scenarios. Furthermore, the concept of safety tolerance was proposed to measure the possibilities of boundary scenarios dropping in safety performance. The applications of helping to construct ODD and compare different control algorithms were discussed. It shows that the IDM performs better than the Wiedemann 99 (W99) model with larger ODD.","Adaptation models; Aerospace electronics; gradient descent; Highly automated vehicle; Life estimation; operational design domain; Roads; Safety; safety performance boundary; Sampling methods; surrogate model; Testing","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","Transport and Planning","Transport and Planning","","",""
"uuid:e438cca0-245c-4bb0-8f5b-4055b186752b","http://resolver.tudelft.nl/uuid:e438cca0-245c-4bb0-8f5b-4055b186752b","A 200Gb/s PAM-4 Transmitter with Hybrid Sub-Sampling PLL in 28nm CMOS Technology","Wang, Zhongkai (University of California); Choi, Minsoo (Samsung Semiconductor); Kwon, Paul (University of California); Lee, Kyoungtae (University of California); Yin, Bozhi (University of California); Liu, Zhaokai (University of California); Park, Kwanseo (University of California); Biswas, Ayan (University of California); Du, S. (TU Delft Electronic Instrumentation)","","2022","This paper presents a complete 200Gb/s PAM-4 transmitter (TX) in 28nm CMOS technology. The transmitter features a hybrid sub-sampling PLL (SSPLL) with a delta-sigma (?S) modulator, clock distribution network with flexible timing control, and data path with a hybrid 5-tap Feed-Forward Equalizer (FFE) and T-coil for bandwidth extension. The prototype chip achieves 4.69 pJ/bit efficiency, 54mV eye height, 0.27UI eye width, and 97% RLM under -6dB channel loss at 50GHz.","28nm; CMOS; SerDes; Sub-sampling PLL; Transmitter","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Instrumentation","","",""
"uuid:20ed3001-1880-435a-86ef-ed276589b826","http://resolver.tudelft.nl/uuid:20ed3001-1880-435a-86ef-ed276589b826","Decentralized coordination for truck platooning","Zeng, Yikai (Student TU Delft); Wang, M. (TU Delft Transport and Planning; Technische Universität Dresden); Rajan, R.T. (TU Delft Signal Processing Systems)","","2022","Coordination for truck platooning refers to the active formation of a group of heavy-duty vehicles traveling at close spacing to reduce the overall truck operations costs. Conventionally, this coordination is achieved by optimizing various truck-related parameters, such as schedules, velocities, and routes, based on an objective function that minimizes a certain cost, for example, fuel usage. However, prevalent algorithms for the coordination problem are typically integer-constrained, which are not only hard to solve but are not readily scalable to increasing fleet sizes and networks. In this paper, to overcome these limitations, we propose a centralized formulation to optimize the truck parameters and solve a multidimensional objective cost function including fuel, operation time costs and preferential penalty. Furthermore, to improve the scalability of our proposed approach, we propose a decentralized algorithm for the platoon coordination problem involving multiple fleets and objectives. We perform both theoretical and numerical studies to evaluate the performance of our decentralized algorithm against the centralized solution. Our analysis indicates that the computation time of the proposed decentralized algorithms is invariant to the increasing fleet size, at the cost of a small relative gap to the optimum cost given by the centralized method. We discuss these results and present future directions for research.","","en","journal article","","","","","","","","","","Transport and Planning","Signal Processing Systems","","",""
"uuid:ef5e2f0e-dd0d-4825-86a0-87753577317a","http://resolver.tudelft.nl/uuid:ef5e2f0e-dd0d-4825-86a0-87753577317a","Assessing the Potential of the Strategic Formation of Urban Platoons for Shared Automated Vehicle Fleets","Wang, S. (TU Delft Mathematical Physics); Correia, Gonçalo (TU Delft Transport and Planning); Lin, H.X. (TU Delft Mathematical Physics; Universiteit Leiden)","","2022","This paper addresses the problem of studying the impacts of the strategic formation of platoons in automated mobility-on-demand (AMoD) systems in future cities. Forming platoons has the potential to improve traffic efficiency, resulting in reduced travel times and energy consumption. However, in the platoon formation phase, coordinating the vehicles at formation locations for forming a platoon may delay travelers. In order to assess these effects, an agent-based model has been developed to simulate an urban AMoD system in which vehicles travel between service points transporting passengers either forming or not forming platoons. A simulation study was performed on the road network of the city of The Hague, Netherlands, to assess the impact on traveling and energy usage by the strategic formation of platoons. Results show that forming platoons could save up to 9.6% of the system-wide energy consumption for the most efficient car model. However, this effect can vary significantly with the vehicle types and strategies used to form platoons. Findings suggest that, on average, forming platoons reduces the travel times for travelers even if they experience delays while waiting for a platoon to be formed. However, delays lead to longer travel times for the travelers with the platoon leaders, similar to what people experience while traveling in highly congested networks when platoon formation does not happen. Moreover, the platoon delay increases as the volume of AMoD requests decreases; in the case of an AMoD system serving only 20% of the commuter trips (by private cars in the case-study city), the average platoon delays experienced by these trips increase by 25%. We conclude that it is beneficial to form platoons to achieve energy and travel efficiency goals when the volume of AMoD requests is high.","","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:a87385e4-99fa-461d-97df-05b74bfa8a1a","http://resolver.tudelft.nl/uuid:a87385e4-99fa-461d-97df-05b74bfa8a1a","DEFEAT: Deep Hidden Feature Backdoor Attacks by Imperceptible Perturbation and Latent Representation Constraints","Zhao, Zhendong (University of Chinese Academy of Sciences; Chinese Academy of Sciences); Chen, Xiaojun (University of Chinese Academy of Sciences; Chinese Academy of Sciences); Xuan, Yuexin (University of Chinese Academy of Sciences; Chinese Academy of Sciences); Dong, Ye (University of Chinese Academy of Sciences; Chinese Academy of Sciences); Wang, Dakui (University of Chinese Academy of Sciences; Chinese Academy of Sciences); Liang, K. (TU Delft Cyber Security)","","2022","Backdoor attack is a type of serious security threat to deep learning models. An adversary can provide users with a model trained on poisoned data to manipulate prediction behavior in test stage using a backdoor. The backdoored models behave normally on clean images, yet can be activated and output incorrect prediction if the input is stamped with a specific trigger pattern. Most existing backdoor attacks focus on manually defining imperceptible triggers in input space without considering the abnormality of triggers' latent representations in the poisoned model. These attacks are susceptible to backdoor detection algorithms and even visual inspection. In this paper, We propose a novel and stealthy backdoor attack - DEFEAT. It poisons the clean data using adaptive imperceptible perturbation and restricts latent representation during training process to strengthen our attack's stealthiness and resistance to defense algorithms. We conduct extensive experiments on multiple image classifiers using real-world datasets to demonstrate that our attack can 1) hold against the state-of-the-art defenses, 2) deceive the victim model with high attack success without jeopardizing model utility, and 3) provide practical stealthiness on image data.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Cyber Security","","",""
"uuid:bf433d06-13a4-4ec0-856f-18b6b08ffb0f","http://resolver.tudelft.nl/uuid:bf433d06-13a4-4ec0-856f-18b6b08ffb0f","Development of an Active Aeroelastic Parametric Wing Apparatus","Schildkamp, R.R.M. (TU Delft Aerospace Structures & Computational Mechanics); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics); Chang, J. (TU Delft Aerospace Structures & Computational Mechanics); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics); Sodja, J. (TU Delft Aerospace Structures & Computational Mechanics)","","2022","This paper presents the development and initial characterization of an active, para- metric wing section with aileron and spoiler control surfaces. This wing section is intended to replace the currently used passive wing section setup and facilitate research in active con- trol techniques of aeroelastic phenomena such as flutter, gust load alleviation, and limit cycle oscillations. Baseline capabilities of the passive setup such as a variable center of mass, pitch axis location and spring stiffnesses are retained, while control surfaces, sensors, a single-board computer, and a mechanism for adjustable aileron free play were includedin the new design. Various system identification tests, such as a ground vibration test, flutter and control reversal speed tests, the actuator frequency response and static aerodynamic interaction between spoiler and aileron, were performed to identify the characteristics of the wing section. Finally, as a proof-of-concept, gust load alleviation tests show the difference between open- and closed-loop gust response when the aileron and spoiler are controlled with PID control.","aeroelasticity; wind tunnel; experimental; design; spoiler; gust load alleviation","en","conference paper","","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:8737cc6e-6434-4167-9e97-57248acccf4b","http://resolver.tudelft.nl/uuid:8737cc6e-6434-4167-9e97-57248acccf4b","Incremental Nonlinear Control for Aeroelastic Wing Load Alleviation and Flutter Suppression","Schildkamp, R.R.M. (TU Delft Aerospace Structures & Computational Mechanics); Chang, J. (TU Delft Aerospace Structures & Computational Mechanics); Sodja, J. (TU Delft Aerospace Structures & Computational Mechanics); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics)","","2022","This paper proposes an incremental nonlinear control method for aeroelastic sys- tem gust load alleviation and active flutter suppression. These two control objectives can be achieved without modifying the control architecture or the control parameters. The proposed method has guaranteed stability in the Lyapunov sense and also has robustness against external disturbances and model mismatches. The effectiveness of this control method is validated by wind tunnel tests of an active aeroelastic parametric wing apparatus, which is a typical wing section containing heave, pitch, flap, and spoiler degrees of freedom. Wind tunnel experiment results show that the proposed nonlinear incremental control can reduce the maximum gust loads by up to 46.7% and the root mean square of gust loads by up to 72.9%, while expanding the flutter margin by up to 15.9%.","aeroservoelasticity; wind tunnel experiment; gust load alleviation; flutter suppression; nonlinear incremental control","en","conference paper","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-11-09","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:b688c4f9-ea41-4153-bff6-437d6f9e5b3d","http://resolver.tudelft.nl/uuid:b688c4f9-ea41-4153-bff6-437d6f9e5b3d","Downsizing the Linear PM Generator in Wave Energy Conversion for Improved Economic Feasibility","Tan, J. (TU Delft Offshore and Dredging Engineering); Wang, X. (TU Delft Transport Engineering and Logistics); Polinder, H. (TU Delft Transport Engineering and Logistics); Jarquin Laguna, A. (TU Delft Offshore and Dredging Engineering); Miedema, S.A. (TU Delft Offshore and Dredging Engineering)","","2022","A crucial part of wave energy converters (WECs) is the power take-off (PTO) mechanism, and PTO sizing has been shown to have a considerable impact on the levelized cost of energy (LCOE). However, as a dominating type of PTO system in WECs, previous research pertinent to PTO sizing did not take modeling and optimization of the linear permanent magnet (PM) generator into consideration. To fill this gap, this paper provides an insight into how PTO sizing affects the performance of linear permanent magnet (PM) generators, and further the techno-economic performance of WECs. To thoroughly reveal the power production of the WEC, both hydrodynamic modeling and generator modeling are incorporated. In addition, three different methods for sizing the linear generator are applied and compared. The effect of the selection of the sizing method on the techno-economic performance of the WEC is identified. Furthermore, to realistically reflect the relevance of PTO sizing, wave resources from three European sea sites are considered in the techno-economic analysis. The dependence of PTO sizing on wave resources is demonstrated.","wave energy converter; linear PM generator; downsizing","en","journal article","","","","","","","","","","","Offshore and Dredging Engineering","","",""
"uuid:005b3281-eb9d-44ce-9e66-ad37e4931dd6","http://resolver.tudelft.nl/uuid:005b3281-eb9d-44ce-9e66-ad37e4931dd6","A TCAD Simulation Study on the Short-circuit Performance of 650V P-pillar Offset Super-junction MOSFET","Yuan, Wucheng (Southern University of Science and Technology); Liu, Ke (Southern University of Science and Technology); Wang, S. (TU Delft Bio-Electronics); Tan, C. (TU Delft Electronic Components, Technology and Materials); Ye, H. (Southern University of Science and Technology)","","2022","The limitation of Silicon based power MOSFET was broken by the super-junction (SJ) structure, which can provide lower specific on-resistance and higher breakdown voltage compared with the conventional power MOSFET structure. Multi-epitaxial and multi-ion-implant technology, as a mature manufacturing process of the SJ structure, has been widely used in the field of SJ-MOSFET. Therefore, this process is applied to construct the cell structure of 650V SJ-MOSFET in our study. Based on practical application, high current caused by unexpected short circuit will induce an increasing of the internal temperature of SJ-MOSFET, which leads to an irreversible damage in the SJ-MOSFET devices. However, the short-circuit robustness of SJ-MOSFET is still unstable, and the structure needs to be further improved. In our study, the electrical performance of a 650V SJ-MOSFET with offset P-pillar is theoretically investigated by means of technology computer aided design (TCAD) when the SJ-MOSFET is short circuited. The results clearly show that the optimized SJ-MOSFET can withstand the source-drain voltage of 400V for at least 10 μs in the case of the short-circuit. The thermal distribution and peak temperature of the cell structure of SJ-MOSFET are also simulated to assist in the analysis of the short circuit capable of the device. In addition, the hole current density distribution of two SJ-MOSFETs is considered to gain insight into the effect of P-pillar parameters on the short-circuit robustness. The result represents that the structure with offset P-pillar can effectively improve the short-circuit capability.","Super-junction structure; Short circuit; P-pillar offset; TCAD simulation","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Bio-Electronics","","",""
"uuid:5b98065c-8069-4933-8f9e-147edb367f80","http://resolver.tudelft.nl/uuid:5b98065c-8069-4933-8f9e-147edb367f80","Study on Reverse Recovery of a P-pillar Tunable Super-Junction MOSFET*","Liu, Ke (Southern University of Science and Technology); Yuan, Wucheng (Southern University of Science and Technology); Wang, S. (TU Delft Bio-Electronics); Tan, C. (TU Delft Electronic Components, Technology and Materials); Ye, H. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology)","","2022","In this paper, a novel bubble-shift super junction (SJ) MOSFET structure is proposed, and its main static electrical parameters and reverse recovery characteristics are simulated by TCAD software tool. By designing the P-pillar ion implantation windows with a certain offset, the bubble-shift SJ-MOSFET contains a curved pillar region in the upper half of the P-pillar. In the reverse recovery test of the proposed bubble-shift SJ-MOSFET, the peak reverse recovery current (I rrm ) is reduced from 16.04 A to 15.21 A, and the current drop rate (di/dt) is reduced from 1587 A/μs to 815 A/μs. Correspondingly, the proposed device achieves a better reverse recovery characteristic while sacrificing a small fraction of the drain-source breakdown voltage (BV) and drain-source special on-resistance (R on,sp ). Compared with the BV of 700 V and the R on,sp of 9 mΩ·cm 2 of the benchmark SJ-MOSFET. The proposed device has a BV of 650 V and a R on,sp of 12.4 mΩ·cm 2 . Mechanistically, the non-uniform depletion of the curved P-pillar reduces the carrier extraction rate, thereby prolonging the reverse current drop time (t f ) and increasing the softness factor (S) of the bubble-shift SJ-MOSFET.","super junction; reverse recovery; P-pillar; bubbleshift; TCAD","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Bio-Electronics","","",""
"uuid:d870e2f8-78ae-43d5-bef2-351fb755d8d6","http://resolver.tudelft.nl/uuid:d870e2f8-78ae-43d5-bef2-351fb755d8d6","Research on Thermal-Mechanical Properties of GaN Power Module Based on QFN Package by Using Nano Copper/Silver Sinter Paste","Li, Shizhen (Southern University of Science and Technology); Liu, X. (TU Delft Electronic Components, Technology and Materials); Fan, Jiajie (Fudan University); Tan, C. (TU Delft Electronic Components, Technology and Materials); Wang, S. (TU Delft Bio-Electronics); Xie, Bin (Hong Kong Applied Science and Technology Research Institute); Ye, H. (Southern University of Science and Technology)","","2022","The wide-bandgap semiconductors represented by GaN have a broad application prospect because of their high service temperature and high switch frequency. Quad-Flat-No-Lead (QFN) Package is currently one of the mainstream packaging methods due to its low cost and high efficiency. However, the low reliability of QFN used in GaN devices is still a crucial problem caused by elevated temperatures and the thermal stress induced by the mismatch of coefficient of thermal expansion (CTE). Therefore, it is necessary to control the temperature inner the package and increase the mechanical property of the bonding layer. In this paper, the finite element method (FEM) with thermal-mechanical coupling is performed to optimize the reliability of the bonding layer by adopting sinter nano Cu and silver. Based on the conventional QFN package module, we tried to add different metallization on the bonding surface to decrease the influence of CTE mismatch. We should note that the Anand viscoplastic model was used in the materials of Sintered Ag and lead-free solder paste presented by SAC305, which were the most commonly used in die-attachment. The results showed that the utilization of nano copper/silver paste could hardly facilitate thermal performance although sintered Ag had excellent thermal conductivity. Since the Anand modules of Ag and SAC305 were different, there were some impacts on the stress distribution and deformation. During the bonding process, a large thermal stress generated between die-attachment layer and Package or the PCB. The die-attachment layer formed by nano Ag paste suffered the smaller thermal stress because its CTE is comparable to that of thermal pad. In terms of sintered Ag, the bonding layer generated more elastic strain. As the deformation recovered to initial stage, the stress decreased because of the elastic strain. And we also found that the Ag metallization could decreased the maximum stress of model at heating stage. But Ag metallization suffered larger thermal stress as the temperature decreased. The selection of connection materials and metallization are a crucial part of design the structure of electronic package. And this paper could provide a reference for optimize the package structure to further improve their reliability in future works.","GaN; QFN; simulation; sintered Ag; thermal stress","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Components, Technology and Materials","","",""
"uuid:b80e041b-07ce-41a9-acd7-0fd0fc0eaca8","http://resolver.tudelft.nl/uuid:b80e041b-07ce-41a9-acd7-0fd0fc0eaca8","Frozen soil hydrological modeling for a mountainous catchment northeast of the Qinghai-Tibet Plateau","Gao, Hongkai (East China Normal University; Chinese Academy of Sciences); Han, Chuntan (Chinese Academy of Sciences); Chen, Rensheng (Chinese Academy of Sciences); Feng, Zijing (East China Normal University); Wang, Kang (East China Normal University); Fenicia, Fabrizio (Swiss Federal Institute of Aquatic Science and Technology); Savenije, Hubert (TU Delft Water Resources)","","2022","Increased attention directed at frozen soil hydrology has been prompted by climate change. In spite of an increasing number of field measurements and modeling studies, the impact of frozen soil on hydrological processes at the catchment scale is still unclear. However, frozen soil hydrology models have mostly been developed based on a bottom-up approach, i.e., by aggregating prior knowledge at the pixel scale, which is an approach notoriously suffering from equifinality and data scarcity. Therefore, in this study, we explore the impact of frozen soil at the catchment scale, following a top-down approach, implying the following sequence: expert-driven data analysis → qualitative perceptual model → quantitative conceptual model → testing of model realism. The complex mountainous Hulu catchment, northeast of the Qinghai-Tibet Plateau (QTP), was selected as the study site. First, we diagnosed the impact of frozen soil on catchment hydrology, based on multi-source field observations, model discrepancy, and our expert knowledge. The following two new typical hydrograph properties were identified: The low runoff in the early thawing season (LRET) and the discontinuous baseflow recession (DBR). Second, we developed a perceptual frozen soil hydrological model to explain the LRET and DBR properties. Third, based on the perceptual model and a landscape-based modeling framework (FLEX-Topo), a semi-distributed conceptual frozen soil hydrological model (FLEX-Topo-FS) was developed. The results demonstrate that the FLEX-Topo-FS model can represent the effect of soil freeze-Thaw processes on hydrologic connectivity and groundwater discharge and significantly improve hydrograph simulation, including the LRET and DBR events. Furthermore, its realism was confirmed by alternative multi-source and multi-scale observations, particularly the freezing and thawing front in the soil, the lower limit of permafrost, and the trends in groundwater level variation. To the best of our knowledge, this study is the first report of LRET and DBR processes in a mountainous frozen soil catchment. The FLEX-Topo-FS model is a novel conceptual frozen soil hydrological model which represents these complex processes and has the potential for wider use in the vast QTP and other cold mountainous regions.","","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:87f7579a-8ad1-4794-826e-dd330b618948","http://resolver.tudelft.nl/uuid:87f7579a-8ad1-4794-826e-dd330b618948","Predictor-based Adaptive Incremental Nonlinear Dynamic Inversion for Fault-Tolerant Flight Control∗","Chang, J. (Xidian University); Guo, Zongyi (Northwestern Polytechnical University); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics)","","2022","The sensor-based Incremental Nonlinear Dynamic Inversion (INDI) control has shown promising robustness in the aerospace research field. This control framework only requires a partial knowledge of plant (control effectiveness) because of its usage of angular accelerations and actuator output measurements. However, there are still un-negligible uncertainties of the control effectiveness model in the flight control system, especially when the aircraft is subjected to structural damage/actuator faults. This paper shows that the conventional INDI control fails to satisfy the sufficient conditions for closed-loop stability in the presence of severe damage. Therefore, this paper also proposes a predictor-based gain adaptive INDI control (named PGA-INDI) which can successfully deal with control effectiveness parametric errors caused by structural damage, actuator faults, and model uncertainties. Various simulations using a public aircraft model have demonstrated the effectiveness of the proposed approach.","Control Effectiveness Uncertainty; Fault-tolerant Flight Control; Incremental Nonlinear Dynamic Inversion; Predictor","en","journal article","","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:5275b845-24ad-498f-aa21-48c36a3d34c1","http://resolver.tudelft.nl/uuid:5275b845-24ad-498f-aa21-48c36a3d34c1","What Determines’ BIM Competition Results of Undergraduate Students in the Architecture, Engineering and Construction Industry?","Ao, Yibin (Chengdu University of Technology); Peng, Panyu (Chengdu University of Technology); Li, Jiayue (Chengdu University of Technology); Bahmani, Homa (Chengdu University of Technology); Wang, T. (TU Delft Design & Construction Management)","","2022","Building Information Modeling (BIM) has become the development trend in the architecture, engineering, and construction (AEC) industry. BIM discipline competition is an effective way for students of AEC-related disciplines to integrate theory with practice, and it is a key link to cultivate qualified BIM practitioners. This study takes participants of the 8th National College BIM Graduation Design Innovation Competition as the research objects. The Technology Acceptance Model and the Theory of Planned Behavior are combined to build a driving factor model of the competitions. Contestants of the competition were asked to complete online questionnaires, and 451 valid samples were finally obtained. Structural Equation Modeling was used to fit the theoretical model, and it was found that: Behavioral Intention to use BIM is directly and positively affected by Attitude, Perceived Behavioral Control, and Perceived Usefulness, as well as indirectly and positively affected by Perceived Usefulness and Perceived Eased of Usefulness. Competition Results is directly and positively affected by Behavioral Intention to use BIM, Perceived Behavioral Control, and Facilitating Conditions. It is also indirectly and positively affected by Attitude, Perceived Behavior Control, Perceived Usefulness, and Perceived Eased of Usefulness. The results show that the situation of students’ participation in BIM competition can be optimized by increasing the publicity and promotion of BIM and related policies, strengthening the construction of supporting teaching facilities, building the integrated curriculum system of BIM technology, and strengthening teacher training. This study provides a theoretical reference for further BIM practice, and it would help improve the corresponding teaching organization and enhance the internal drive of students’ BIM learning.","BIM; technology acceptance model; theory of planned behavior; behavioral intention; competition results","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:5ab07e69-f948-4e72-b321-af2a425c1cf7","http://resolver.tudelft.nl/uuid:5ab07e69-f948-4e72-b321-af2a425c1cf7","Evolutionary Analysis of Prefabrication Implementation in Construction Projects under Low-Carbon Policies","Shi, Qianqian (Nanjing University of Aeronautics and Astronautics); Wang, Ziyuan (Nanjing University of Aeronautics and Astronautics); LI, Boya (Nanjing University of Aeronautics and Astronautics); Hertogh, M.J.C.M. (TU Delft Integral Design & Management); Wang, Shuyi (National University of Singapore; Southeast University)","","2022","In the context of carbon peak and carbon neutral policies, low-carbon construction has been the focus of most countries worldwide. As one of the most effective ways to achieve green construction, many countries have launched low-carbon policies to promote the development of prefabrication. However, the effectiveness and influencing factors of low-carbon policies on prefabrication need to be further verified under the dynamic game between the government and the construction enterprise. Therefore, this study considered subsidy and carbon tax policies and developed an evolutionary game model to promote the development of the prefabricated construction market. The evolutionary stable strategy of the government and construction enterprise under different scenarios was obtained. Subsequently, a numerical analysis was conducted to further investigate the impact of the key factors on the stable strategy. The results showed that an appropriate hybrid policy of subsidies and taxes could positively promote the prefabrication implementation of the construction enterprise. The government should adopt an appropriate policy intensity according to the maturity of the market. This study can provide effective guidance and practical enlightenment for the government to achieve low-carbon, green, and sustainable construction.","green construction; prefabrication; low-carbon policy; evolutionary game","en","journal article","","","","","","","","","","","Integral Design & Management","","",""
"uuid:2ef56fe3-6fca-4b53-9ef7-3dae4fbbed78","http://resolver.tudelft.nl/uuid:2ef56fe3-6fca-4b53-9ef7-3dae4fbbed78","Effect of rice straw powder on properties of one-part alkali-activated slag","Yin, Kangting (Hohai University); Jiang, Yaqing (Hohai University); Wang, Yu (Hohai University); Zhao, Wenhao (Hohai University); Pan, Zhenghua (Hohai University); Li, Z. (TU Delft Materials and Environment)","","2022","One-part alkali-activated slag (AAS) as a binder material has a promising application in the construction industry. The properties of one-part AAS incorporating agricultural wastes have been seldom studied. In this paper, the fresh and hardened properties of one-part AAS with the addition of rice straw powder (RSP) were investigated. The reaction rate in the acceleration period of AAS is reduced by RSP. The compressive strength of the mixture decreases with the introduction of RSP, while the flexural strength increases. The porosity of the hardened mixtures becomes lower when RSP was incorporated. N-(C)-A-S-H gel was detected in the system when 4.2% RSP was present. The RSP reduces the early-age autogenous shrinkage of AAS by providing internal curing to the matrix, but its effect on long-term drying shrinkage is limited.","one-part material; alkali-activated slag; rice straw powder; hydration; microstructure","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:3627e22b-1d8b-4724-86de-7eae834314fb","http://resolver.tudelft.nl/uuid:3627e22b-1d8b-4724-86de-7eae834314fb","Overview of the SmartX Wing Technology Integrator","De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics); Mkhoyan, T. (TU Delft Arts & Crafts; TU Delft Aerospace Structures & Computational Mechanics); Nazeer, N. (TU Delft Structural Integrity & Composites); Stuber, V.L. (TU Delft Novel Aerospace Materials); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics); Mkhoyan, A. (TU Delft Aerospace Structures & Computational Mechanics); Groves, R.M. (TU Delft Structural Integrity & Composites); van der Zwaag, S. (TU Delft Novel Aerospace Materials); Sodja, J. (TU Delft Aerospace Structures & Computational Mechanics)","","2022","This article describes the challenges of integrating smart sensing, actuation, and control concepts into an over-sensed and over-actuated technology integrator. This technology integrator has more control inputs than the expected responses or outputs (over-actuated), and its every state is measured using more than one sensor system (over-sensed). The hardware integration platform is chosen to be a wind tunnel model of a low-speed aircraft wing such that it can be tested in a large university-level wind tunnel. This hardware technology integrator is designed for multiple objectives. The nature of these objectives is aerodynamic, structural, and aeroelastic, or, more specifically; drag reduction, static and dynamics loads control, aeroelastic stability control, and lift control. Enabling technologies, such as morphing, piezoelectric actuation and sensing, and fibre-optic sensing are selected to fulfil the mentioned objectives. The technology integration challenges are morphing, actuation integration, sensor integration, software and data integration, and control system integration. The built demonstrator shows the intended level of technology integration.","autonomous wing; over-actuated wing; over-sensed wing; technology demonstrator","en","journal article","","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:bc68abb3-9345-40a6-8132-696ff076b5dd","http://resolver.tudelft.nl/uuid:bc68abb3-9345-40a6-8132-696ff076b5dd","Combined effects of photoaging and natural organic matter on the colloidal stability of nanoplastics in aquatic environments","Xu, Yanghui (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Ou, Q. (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Li, Xiaoming (Chinese Academy of Sciences); Wang, Xintu (Chinese Academy of Sciences; Guilin University of Technology); van der Hoek, J.P. (TU Delft Sanitary Engineering; Waternet); Liu, Gang (Chinese Academy of Sciences)","","2022","The transport and fate of nanoplastics (NPs) in aquatic environments are closely associated with their colloidal stability, which is affected by aging and natural organic matter (NOM) adsorption. This study systematically investigated the combined effects of photoaging and NOM (e.g. humic acids, HA; and a model protein, bovine serum albumin, BSA) on the aggregation kinetics of NPs (polystyrene, PS) in NaCl and CaCl2 solutions. Our results showed that photoaged NPs adsorbed less HA than pristine NPs due to weaker hydrophobic and π-π interactions. In return, HA showed weaker impacts on NPs’ stability after photoaging. Differently, photoaged NPs absorbed more BSA than pristine NPs due to stronger hydrogen bonding and electrostatic attraction. Thus, the inhibitory effects of BSA on the aggregation kinetics of NPs were enhanced after photoaging. Regarding the effects of NOM on the aging of NPs, our results showed that HA competed with NPs for photons and underwent photo-degradation. Subsequently, the destruction/reconstruction of adsorbed HA increased (in NaCl) or decreased (in CaCl2) the stability of NPs. Notably, light radiation-induced flocculation of BSA molecules, which wrapped and integrated NPs and lead to their destabilization. Overall, this study provided new insights into the aggregation behavior of NPs in aquatic systems, which have significant implications for predicting the transport and fate of NPs in complex real-world environments.","Nanoplastics; Colloidal stability; Natural organic matter; Photoaging; Steric repulsion; Photo-flocculation","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:1790c9a9-7a73-4aea-9829-c2364a316899","http://resolver.tudelft.nl/uuid:1790c9a9-7a73-4aea-9829-c2364a316899","Spatial-temporal analysis of road raveling and its correlation with traffic flow characteristics","Wang, Z. (TU Delft Transport and Planning); Krishnakumari, P.K. (TU Delft Transport and Planning); Anupam, K. (TU Delft Pavement Engineering); van Lint, J.W.C. (TU Delft Transport and Planning); Erkens, S. (TU Delft Pavement Engineering)","","2022","Understanding the relationship between pavement raveling and traffic characteristics is important to pavement management and maintenance planning. In this work, we propose a framework to empirically quantify this relationship. It consists of an alignment method to tackle the inconsistent spatial-temporal scales of the raveling and traffic measurements and we propose spatial-temporal maps to qualitatively analyze and compare the data. A non-parametric correlation is done on the aligned raveling and traffic flow data. This framework is applied to five study areas in the Dutch highway network. The correlation analysis of the study areas provides empirical evidence to a commonly held theory that traffic flow has effects on raveling. Categorizing the correlation by lanes indicates that the raveling is homogeneous in the through or auxiliary lanes, and the severe raveled sections are parallel to the road discontinuity, suggesting the potential effect of mandatory lane changing on raveling development. The proposed framework can be employed in empirical raveling models that predict raveling based on traffic and other factors.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-05-01","","","Transport and Planning","","",""
"uuid:86b6baee-c5af-4e70-a3c8-8f2bf5fab46f","http://resolver.tudelft.nl/uuid:86b6baee-c5af-4e70-a3c8-8f2bf5fab46f","Train scheduling with flexible coupling and decoupling at stations for an urban rail transit line","Zhao, Kangqi (Beijing Jiaotong University); Wang, Yihui (Beijing Jiaotong University); Ding, Miaomiao (Beijing Jiaotong University); Li, Shukai (Beijing Jiaotong University); Quaglietta, E. (TU Delft Transport and Planning); Meng, Lingyun (Beijing Jiaotong University)","","2022","More and more people in big cities choose urban rail transit as the main means of public transportation. With the increasing unbalanced passenger flow in time and space, the traditional operation mode with fixed train formation (or composition) is difficult to satisfy the varying passenger demands. This paper distinguishes different train formations in urban rail transit, and specifies the definition and the operation process for flexible composition of trains. An integrated train scheduling problem with flexible train composition is proposed, where the key constraints for practical train operation and the utilization of rolling stocks are considered. These constraints involve turnaround constraints, flexible train formation constraints, headway constraints and passenger flow constraints. The resulting problem is a mixed integer nonlinear programming problem, which can be transformed into a mixed integer linear programming problem and then be solved using existing optimization solvers, e.g., CPLEX. Based on the practical infrastructure and passenger demand data of the Beijing Daxing International Airport Express, a set of case studies is carried out to demonstrate the effectiveness of the presented model and solution approach. The computational results show that the train schedule with flexible train compositions can largely reduce the number of waiting passenger when compared with the train schedules with fixed train compositions and with multiple train compositions.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Transport and Planning","","",""
"uuid:3d41ce71-2b76-4b01-ab16-e81f044d9774","http://resolver.tudelft.nl/uuid:3d41ce71-2b76-4b01-ab16-e81f044d9774","Built environment and travel behavior in rural areas: A scientometric literature review","Ao, Yibin (Chengdu University of Technology); Li, Mingyang (Chengdu University of Technology); Ding, Xuan (Chengdu University of Technology); Zheng, Junjie (Chengdu University of Technology); Xiao, Shan (Chengdu University of Technology); Deng, Shulin (Chengdu University of Technology); Zhang, Zijun (Chengdu University of Technology); Wang, Yan (Sichuan College of Architectural Technology); Wang, T. (TU Delft Design & Construction Management); Martek, Igor (Deakin University)","","2022","With the rise of global urbanization, the rural built environment has undergone tremendous changes. As such, the rural built environment impacts on residents’ daily travel behavior is getting more researchers’ attention. To date, most of the research focuses on urban areas in developed countries. To understand the state-of-the-art of interplay between the rural built environment and travel behaviors and to identify future research directions, this study adopts a science mapping approach to identify the relevant topics, authors, journals, and countries of the research done. This study proceeds through bibliometric retrieval of articles from 2005, followed by scientometric analysis and qualitative discussion. 37 documents are found to compare urban and rural domains, with 28 on the rural built environment. Research gaps and the research trends are discussed, of which the main themes are multi-dimensional correlation comparison of rural transportation service systems and emerging transportation modes, the influence of rural social and cultural factors on travel behavior, and low-carbon sustainable transportation. This review provides empirical foundation for current state-of-the-art and identifies the future research directions, specifically for rural built environment impact on travel behavior.","rural built environment; travel behavior; science mapping; scientometric analysis; literature review","en","review","","","","","","","","","","","Design & Construction Management","","",""
"uuid:71a3942a-f4ac-4116-829a-0b4a3af7589c","http://resolver.tudelft.nl/uuid:71a3942a-f4ac-4116-829a-0b4a3af7589c","The Impact of Public Opinion Pressure on Construction Company Green Innovations: The Mediating Effect of Leaders' Environmental Intention and the Moderating Effect of Environmental Regulation","Wang, Bo (Southwest University of Science and Technology); Han, Shan (Southwest University of Science and Technology); Ao, Yibin (Chengdu University of Technology); Liao, Fangwei (Southwest University of Science and Technology); Wang, T. (TU Delft Design & Construction Management); Chen, Yunfeng (Purdue University)","","2022","Media has paid more attention recently on environmental issues caused by construction companies which imposes public opinion pressure on construction companies and could potentially impact their decision-making processes for green innovations. However, research on the relationship between public opinions pressure and construction company green innovation behavior is still limited. To understand how such public opinions pressure can impact construction companies' green transition and formulate advice accordingly, it is necessary to use empirical data to find the correlations. Therefore, this research has gathered questionnaire data of the construction companies in Chengdu-Chongqing economic circle of China to study the influencing mechanism of environmental public opinion pressure on enterprise green innovation behavior, analyzes the realization path of leaders' environmental intention as a mediating variable in the impact of environmental public opinion pressure on enterprise green innovation behavior, and reveals the role boundary of environmental regulation as a moderating variable in the impact of environmental public opinion pressure on enterprise green innovation behavior. The results show that environmental public opinion pressure has a significant positive impact on enterprise green innovation behavior. More specifically, enterprise green innovation behavior is affected by leaders' environmental intention and the latter plays a partial mediating role between environmental public opinion pressure and enterprise green innovation behavior. Environmental regulation also enhances the sensitivity of companies to environmental public opinion pressure, and therefore can significantly strengthen the relationship between environmental public opinion pressure and enterprise green innovation behavior. Further research find that, compared with incentive-based environmental regulations, mandatory environmental regulations make companies more sensitive to environmental public opinion pressure and has a more significant positive moderating effect. The research conclusions could be used to provide theoretical reference with empirical data for accelerating the green innovation transformation and promoting the high-quality development in the construction industry.","","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:601e8d97-24b8-43fc-9910-25872b5e3113","http://resolver.tudelft.nl/uuid:601e8d97-24b8-43fc-9910-25872b5e3113","Nondestructive Monitoring Hydration of Belite Calcium Sulfoaluminate Cement by EIS Measurement","Chi, Lin (University of Shanghai for Science and Technology); Wang, Mian (University of Shanghai for Science and Technology); Wang, Zhuolin (Shanghai Research Institute of Building Sciences); Li, Z. (TU Delft Materials and Environment); Peng, Bin (University of Shanghai for Science and Technology); Li, Junjie (University of Shanghai for Science and Technology)","","2022","In this study, the impact of water-to-cement (w/c) ratios of belite calcium sulfoaluminate cement (BCSA) on the hydration kinetics and the electrochemical impedance spectroscopy (EIS) parameters is studied. According to the analysis of classic hydration measurements, such as calorimetry tests, chemical shrinkage content, and chemically bound water content, it can be concluded that a higher w/c ratio clearly accelerates the hydration of BCSA cement paste. The electrical resistivity of BCSA0.35 cement paste is more than 4.5 times that of BCSA0.45 and BCSA0.5, due to the gradually densified micropore structure blocking the electrical signal transmission rather than the free charged-ion content. The porosity of BCSA0.5 is 27.5% higher than that of BCSA0.35 and 7.8% higher than that of BCSA0.45, which proves the resistivity is clearly related to the variation in microstructure, especially for the porosity and pore size distribution. The novelty of this study is the linear regression with logarithm terms of electrical resistivity and classic hydration parameters such as chemical shrinkage, cumulative hydration heat, and chemically bound water is established to extend the classical expression of cement hydration degree. It indicates that the electrochemical impedance spectroscopy can be taken as a nondestructive testing measurement to real-time monitor the cement hydration process of cement-based materials.","belite calcium sulfoaluminate cement; resistivity; cement hydration; EIS measurement","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:86e2eed5-386e-410c-ab08-0d5a99eefab1","http://resolver.tudelft.nl/uuid:86e2eed5-386e-410c-ab08-0d5a99eefab1","Evaluation of the Aging Properties of Terminal Blend Hybrid Asphalt Based on Chemical and Rheological Methods","Wang, S. (TU Delft Pavement Engineering; Tongji University); Huang, Weidong (Tongji University); Liu, X. (TU Delft Pavement Engineering); Lin, P. (TU Delft Pavement Engineering)","","2022","The chemical and rheological properties of terminal blend hybrid asphalt (TBHA) contributing to the consumption of waste tires before and after aging were studied. Styrene-butadiene-styrene (SBS) polymer, sulphur, crumb rubber (CR), and neat asphalt were chosen to prepare the TBHA. The short-term aging (STA) and long-term aging (LTA) of TBHA were simulated using a rolling thin film oven test (RTFOT) and pressure aging vessel (PAV), separately. The chemical and rheological properties of the TBHA were tested. The results show that the G* and G*/sin δ of TBHA ares generally lower than SBS-modified asphalt (SBSMA) at 76 °C, and the δ, Jnr0.1, and Jnr3.2 of TBHA are generally higher than SBSMA at 76 °C. Additionally, with the decrease of CR, the G* and G*/sin δ of TBHA decreased more obviously, and the G* and G*/sin δ of 5T_3S_0.2Sul (5 wt% CR, 3 wt% SBS, and 0.2 wt% sulphur) were the smallest. Moreover, during the STA, the SBS modifier in the TBHA degraded and made the bitumen predominantly soft; however, during the LTA, the hardening of the bitumen played a dominant role and increased its elasticity. The superior anti-aging properties of TBHA (both STA and LTA) are further demonstrated.","terminal blend hybrid asphalt; rheological properties; short-term aging; long-term aging","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:ed74c3d8-39d1-454c-96fe-e0c3eb148cf8","http://resolver.tudelft.nl/uuid:ed74c3d8-39d1-454c-96fe-e0c3eb148cf8","Ensemble of Metaheuristic and Exact Algorithm Based on the Divide-And-Conquer Framework for Multisatellite Observation Scheduling","Wu, Guohua (Central South University China); Luo, Qizhang (Central South University China; National University of Singapore); Du, Xiao (Central South University China); Chen, Yingguo (National University of Defense Technology); Suganthan, Ponnuthurai Nagaratnam (Qatar University; Nanyang Technological University); Wang, X. (TU Delft Learning & Autonomous Control)","","2022","Satellite observation scheduling plays a significant role in improving the efficiency of Earth observation systems. To solve the large-scale multisatellite observation scheduling problem, this article proposes an ensemble of metaheuristic and exact algorithms based on a divide-And-conquer framework (EHE-DCF), including a task allocation phase and a task scheduling phase. In the task allocation phase, each task is allocated to a proper orbit based on a metaheuristic incorporated with a probabilistic selection and a tabu mechanism derived from ant colony optimization and tabu search, respectively. In the task scheduling phase, we construct a task scheduling model for every single orbit and solve the model by using an exact method (i.e., branch and bound, B&B). The task allocation and task scheduling phases are performed iteratively to obtain a promising solution. To validate the performance of the EHE-DCF, we compare it with B&B, three divide-And-conquer-based metaheuristics, and a state-of-The-Art metaheuristic. Experimental results show that the EHE-DCF can obtain higher scheduling profits and complete more tasks compared with existing algorithms. The EHE-DCF is especially efficient for large-scale satellite observation scheduling problems.","Divide-And-conquer framework (DCF); Ensemble algorithm; Exact algorithm; Metaheuristic algorithm; Observation satellite scheduling","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Learning & Autonomous Control","","",""
"uuid:42562fa2-b725-4bff-9a56-32bdfc6fcb50","http://resolver.tudelft.nl/uuid:42562fa2-b725-4bff-9a56-32bdfc6fcb50","Motion-Guided Global-Local Aggregation Transformer Network for Precipitation Nowcasting","Dong, Xichao (Beijing Institute of Technology; Beijing Institute of Technology Chongqing Innovation Center, Chongqin); Zhao, Zewei (Beijing Institute of Technology); Wang, Yupei (Beijing Institute of Technology); Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Hu, Cheng (Beijing Institute of Technology)","","2022","Nowadays deep learning-based weather radar echo extrapolation methods have competently improved nowcasting quality. Current pure convolutional or convolutional recurrent neural network-based extrapolation pipelines inherently struggle in capturing both global and local spatiotemporal interactions simultaneously, thereby limiting nowcasting performances, e.g., they not only tend to underestimate heavy rainfalls' spatial coverage and intensity but also fail to precisely predict nonlinear motion patterns. Furthermore, the usually adopted pixel-wise objective functions lead to blurry predictions. To this end, we propose a novel motion-guided global-local aggregation Transformer network for effectively combining spatiotemporal cues at different time scales, thereby strengthening global-local spatiotemporal aggregation urgently required by the extrapolation task. First, we divide existing observations into both short- and long-term sequences to represent echo dynamics at different time scales. Then, to introduce reasonable motion guidance to Transformer, we customize an end-to-end module for jointly extracting motion representation of short- and long-term echo sequences (MRS, MRL), while estimating optical flow. Subsequently, based on Transformer architecture, MRS is used as queries to retrospect the most useful information from MRL for an effective aggregation of global long-term and local short-term cues. Finally, the fused feature is employed for future echo prediction. Additionally, for the blurry prediction problem, predictions from our model trained with an adversarial regularization achieve superior performances not only in nowcasting skill scores but also in precipitation details and image clarity over existing methods. Extensive experiments on two challenging radar echo datasets demonstrate the effectiveness of our proposed method.","Weather radar; precipitation nowcasting; attention mechanism; optical flow; Transformers","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Microwave Sensing, Signals & Systems","","",""
"uuid:c956b7ae-daa8-49c4-bd1f-9f6e5a73481c","http://resolver.tudelft.nl/uuid:c956b7ae-daa8-49c4-bd1f-9f6e5a73481c","Spectral characteristics of gold nanoparticle doped optical fibre under axial strain","Wang, X. (TU Delft Structural Integrity & Composites); Benedictus, R. (TU Delft Structural Integrity & Composites); Groves, R.M. (TU Delft Structural Integrity & Composites)","","2022","Nanoparticle (NP) doping of optical fibres can be used to increase the intensity of the backscattered light used for distributed strain sensing and has shown the advantages of high precision strain detection and multiplex sensing experimentally. However, the backscatter spectral characteristics of NP-doped optical fibres have not been described even though they are quite different from the spectra from fibre Bragg gratings (FBGs) or commercial single mode fibres. In this paper, gold NPs, used as the contrast agent in the optical fibre to increase the intensity of the backscattered light, were investigated from the aspect of their spectra. A single scattering model with Mie theory and an effective refractive index (RI) model were used to evaluate the backscattered light spectra and the Monte Carlo Method was used for seeding NPs. The results showed that the strain responsivity of gold-NP doped fibres with low volume ratio doping (single scattering restriction) are close to FBGs and commercial fibres. High volume ratios of gold NP doping increase the imaginary part of the RI of the optical fibre, which has a significant influence on the spectra in the wavenumber domain. These theoretical insights may promote the future engineering design of NP-doped fibre sensors.","","en","journal article","","","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:a540cd9c-b5e7-4352-b908-76886bc7cb3d","http://resolver.tudelft.nl/uuid:a540cd9c-b5e7-4352-b908-76886bc7cb3d","Rail break prediction and cause analysis using imbalanced in-service train data","Zeng, Cheng (The University of Newcastle, Australia); Huang, Jinsong (The University of Newcastle, Australia); Wang, H. (TU Delft Railway Engineering); Xie, Jiawei (The University of Newcastle, Australia); Huang, Shan (The University of Newcastle, Australia)","","2022","Timely detection and identification of rail breaks are crucial for safety and reliability of railway networks. This paper proposes a new deep learning-based approach using the daily monitoring data from in-service trains. A time-series generative adversarial network (TimeGAN) is employed to mitigate the problem of data imbalance and preserve the temporal dynamics for generating synthetic rail breaks. A feature-level attention-based bidirectional recurrent neural networks (AM-BRNN) is proposed to enhance feature extraction and capture two-direction dependencies in sequential data for accurate prediction. The proposed approach is implemented on a three-year dataset collected from a section of railroads (up to 350 km) in Australia. A real-life validation is carried out to evaluate the prediction performance of the proposed model, where historical data is used to train the model and future ’unseen’ rail breaks along the whole track section are used for testing. The results show that the model can successfully predict 9 out of 11 rail breaks three months ahead of time with a false prediction of non-break of 8.2%. Predicting rail breaks three months ahead of time will provide railroads enough time for maintenance planning. Given the prediction results, SHAP method is employed to perform cause analysis for individual rail break. The results of cause analysis can assist railroads to plan appropriate maintenance to prevent rail breaks.","rail break prediction; in-service train data; deep learning-based approach; real-life validation; cause analysis","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Railway Engineering","","",""
"uuid:c89df08a-a597-4d74-9508-c382b26445c0","http://resolver.tudelft.nl/uuid:c89df08a-a597-4d74-9508-c382b26445c0","On-Line Black-Box Aerodynamic Performance Optimization for a Morphing Wing With Distributed Sensing and Control","Mkhoyan, T. (TU Delft Arts & Crafts; TU Delft Aerospace Structures & Computational Mechanics); Ruland, O.L. (TU Delft Control & Operations); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics); Wang, Xuerui (TU Delft Control & Operations; TU Delft Aerospace Structures & Computational Mechanics)","","2022","Inspired by nature, smart morphing technologies enable the aircraft of tomorrow to sense their environment and adapt the shape of their wings in flight to minimize fuel consumption and emissions. A primary challenge on the road to this feature is how to use the knowledge gathered from sensory data to establish an optimal shape adaptively and continuously in flight. To address this challenge, this article proposes an online black-box aerodynamic performance optimization architecture for active morphing wings. The proposed method integrates a global online-learned radial basis function neural network (RBFNN) model with an evolutionary optimization strategy, which can find global optima without requiring in-flight local model excitation maneuvers. The actual wing shape is sensed via a computer vision system, while the optimized wing shape is realized via nonlinear adaptive control. The effectiveness of the optimization architecture was experimentally validated on an active trailing-edge (TE) camber morphing wing demonstrator with distributed sensing and control in an open jet wind tunnel. Compared with the unmorphed shape, a <inline-formula> <tex-math notation=""LaTeX"">$7.8\%$</tex-math> </inline-formula> drag reduction was realized, while achieving the required amount of lift. Further data-driven predictions have indicated that up to <inline-formula> <tex-math notation=""LaTeX"">$19.8\%$</tex-math> </inline-formula> of drag reduction is achievable and have provided insight into the trends in optimal wing shapes for a wide range of lift targets.","Adaptation models; Aerodynamics; Aircraft; Black-box optimization; Computational modeling; evolutionary optimization; morphing; neural networks; Optimization; Sensors; Shape; vision-based control; wind tunnel experiment","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-06-01","","Control & Operations","Arts & Crafts","","",""
"uuid:20e9db2d-9a78-4ad6-a046-d16ee1c31947","http://resolver.tudelft.nl/uuid:20e9db2d-9a78-4ad6-a046-d16ee1c31947","Cancer Diagnosis Using Terahertz-Graphene-Metasurface-Based Biosensor with Dual-Resonance Response: Nanomaterials","Tan, C. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology); Wang, S. (TU Delft Bio-Electronics; Southern University of Science and Technology); Li, Shizhen (Southern University of Science and Technology); Liu, X. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology); Wei, Jia (Guangzhou Regenerative Medicine and Health Guangdong Laboratory); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Ye, H. (Southern University of Science and Technology)","","2022","Owing to the outstanding physical properties of graphene, its biosensing applications implemented by the terahertz metasurface are widely concerned and studied. Here, we present a novel design of the graphene metasurface, which consists of an individual graphene ring and an H-shaped graphene structure. The graphene metasurface exhibits a dual-resonance response, whose resonance frequency strongly varies with the geometrical parameters of the proposed metasurface, the carrier density of graphene, and the analyte composition. The transparency window, including width and position, can be artificially controlled by adjusting the geometrical parameters or the Fermi energy. Furthermore, the sensing parameters of the graphene metasurface for cancerous and normal cells are investigated, focusing on two factors, namely cell quantity and position on the metasurface. The simulated results clearly show that the theoretical sensitivity, figure of merit, and quantity of the graphene metasurface for breast cells reach 1.21 THz/RIU, 2.75 RIU (Formula presented.), and 2.43, respectively. Our findings may open up new avenues for promising applications in the diagnosis of cancers.","graphene metasurface; terahertz sensing; dual-resonance response; cancer diagnosis","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:9c3e1d1e-9a5b-47a3-b5f2-21bf4b3af6eb","http://resolver.tudelft.nl/uuid:9c3e1d1e-9a5b-47a3-b5f2-21bf4b3af6eb","Effectiveness of trip planner data in predicting short-term bus ridership","Wang, Z. (TU Delft Transport and Planning); Pel, A.J. (TU Delft Transport and Planning); Verma, T. (TU Delft Policy Analysis); Krishnakumari, P.K. (TU Delft Transport and Planning); van Brakel, Peter (REISinformatiegroep); van Oort, N. (TU Delft Transport and Planning)","","2022","Predictions on public transport ridership are beneficial as they allow for sufficient and cost-efficient deployment of vehicles. At an operational level, this relates to short-term predictions with lead times of less than an hour. Where conventional data sources on ridership, such as Automatic Fare Collection (AFC) data, may have longer lag times, in contrast, trip planner data is often available in (near) real-time. This paper analyzes how such data from a trip planner app can be utilized for short-term bus ridership predictions. This is combined with AFC data (in this case smart card data) to construct a ground-truth on actual ridership. The trip planner data is studied using correlation analysis to select informative variables, that are then used to develop 4 supervised machine learning models (linear, k-nearest neighbors, random forest, and gradient boosting decision tree). The best performing model relies on random forest regression and reduces the error by approximately half compared to a baseline model based on the weekly trend. We show that this model performance is maintained even for prediction lead times up to 30 minutes ahead, and for different periods of the day.","Public Transport; Trip Planner; Bus Ridership Prediction; Machine Learning","en","conference paper","CASPT","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Transport and Planning","","",""
"uuid:17487f41-b96a-4063-a64f-9760ff465c17","http://resolver.tudelft.nl/uuid:17487f41-b96a-4063-a64f-9760ff465c17","Measuring Bed Exchange Properties of Cohesive Sediments Using Tripod Data","Zhou, Z. (TU Delft Coastal Engineering; East China Normal University); Ge, Jianzhong (Shanghai Estuarine and Coastal Science Research Center; Institute of Eco-Chongming (IEC); East China Normal University); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; East China Normal University; Deltares); Gu, Jinghua (East China Normal University); Ding, Pingxing (East China Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2022","The Krone–Partheniades (K-P) framework has been used for decades to quantify and analyze the sediment exchange at a water–bed interface. Measuring the erosion and deposition parameters that are part of this framework requires time-consuming field observations. Additionally, the erosion parameters are measured independently of deposition parameters, while in reality they are coupled. In numerical models applying the K-P framework these parameters are often assumed to be constant in time and mutually independent. In this study, we develop a relatively simple methodology to determine the erosion and deposition parameters, using conventional near-bed observations of bed level, sediment concentration and flow velocity. This methodology is subsequently applied to tripod observations collected in the Changjiang estuary, China, to compute continuous time-varying erosion and settling parameters. We propose a diagram to visualize the interdependency and accuracy of erosion and deposition parameters, which is the input for K-P framework models requiring this interdependency","Krone–Partheniades equations; observations techniques; settling velocity; critical shear stress","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:d5560d38-7c94-4b92-9263-37da4d931367","http://resolver.tudelft.nl/uuid:d5560d38-7c94-4b92-9263-37da4d931367","Experimental and theoretical study on residual ultimate strength after impact of CF/PEEK-titanium hybrid laminates with nano-interfacial enhancement","Ji, C. (TU Delft Structural Integrity & Composites; Harbin Institute of Technology (Shenzen)); Hu, Jiqiang (Harbin Institute of Technology); Sadighi, M. (TU Delft Structural Integrity & Composites); Alderliesten, R.C. (TU Delft Structural Integrity & Composites); Wang, Bing (Harbin Institute of Technology); Sun, Yuguo (Harbin Institute of Technology)","","2022","Fiber metal laminates (FMLs) provide a reliable approach for achieving lightweight in high-speed aerospace vehicles. However, the weak interfacial properties between metals and composites could significantly affect the deformation and failure modes of FMLs. In this paper, the low-velocity impact responses and damage mechanisms of CF/PEEK-Ti hybrid laminates with nano-interfacial enhancement by multi-walled carbon nanotubes (CNTs) were characterized and analyzed. The post-impact residual tensile strengths (RTS) were investigated experimentally using quasi-static uniaxial tests combined with digital image correlation, and were evaluated theoretically by developing an analytical prediction model that considers the internal thermal stress and dent geometry. Results show that the initial delamination thresholds of force and displacement during impact can be effectively increased via interfacial enhancement of CNT network. By using a 5% decrease in RTS retention rate as a criterion for damage tolerance, a significant strength decrease starts to appear at 3 J for the sandblasted-only laminates, which is improved to 10 J for the laminates with nano-interfacial enhancement. The proposed unified constitutive model can yield an acceptable prediction for RTS and failure strain of the hybrid laminate after impact, providing a guidance for the structural design and engineering applications of FMLs.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-06-01","","","Structural Integrity & Composites","","",""
"uuid:16a0f489-aa91-4693-a9f7-30d4402a1cf6","http://resolver.tudelft.nl/uuid:16a0f489-aa91-4693-a9f7-30d4402a1cf6","Interactive Data Comics","Wang, Zezhong (University of Edinburgh); Romat, Hugo (ETH Zürich); Chevalier, Fanny (University of Toronto); Riche, Nathalie Henry (Microsoft Research); Murray-Rust, D.S. (TU Delft Human Information Communication Design); Bach, Benjamin (University of Edinburgh)","","2022","This paper investigates how to make data comics interactive. Data comics are an effective and versatile means for visual communication, leveraging the power of sequential narration and combined textual and visual content, while providing an overview of the storyline through panels assembled in expressive layouts. While a powerful static storytelling medium that works well on paper support, adding interactivity to data comics can enable non-linear storytelling, personalization, levels of details, explanations, and potentially enriched user experiences. This paper introduces a set of operations tailored to support data comics narrative goals that go beyond the traditional linear, immutable storyline curated by a story author. The goals and operations include adding and removing panels into pre-defined layouts to support branching, change of perspective, or access to detail-on-demand, as well as providing and modifying data, and interacting with data representation, to support personalization and reader-defined data focus. We propose a lightweight specification language, COMICSCRIPT, for designers to add such interactivity to static comics. To assess the viability of our authoring process, we recruited six professional illustrators, designers and data comics enthusiasts and asked them to craft an interactive comic, allowing us to understand authoring workflow and potential of our approach. We present examples of interactive comics in a gallery. This initial step towards understanding the design space of interactive comics can inform the design of creation tools and experiences for interactive storytelling.","Data comics; interactive storytelling; Non-linear narrative","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Human Information Communication Design","","",""
"uuid:896a60a9-8b6a-4079-8dc7-6f80a69ae1d0","http://resolver.tudelft.nl/uuid:896a60a9-8b6a-4079-8dc7-6f80a69ae1d0","A Hybrid Deep Learning Pipeline for Improved Ultrasound Localization Microscopy","Stevens, T.N.M. (Eindhoven University of Technology); Herbst, Elizabeth B. (Philips Research); Luijten, Ben (Eindhoven University of Technology); Ossenkoppele, B.W. (TU Delft ImPhys/Imaging Physics; TU Delft ImPhys/Medical Imaging; Eindhoven University of Technology); Voskuil, Thierry J. (Eindhoven University of Technology); Wang, Shiying (Philips Research); Youn, Jihwan (Eindhoven University of Technology); Errico, Claudia (Philips Research); Pezzotti, Nicola (Eindhoven University of Technology; Philips Research)","","2022","The image quality of ultrasound localization microscopy (ULM) images is driven by the ability to accurately detect and track the location of microbubbles (MBs) in vascular networks. This task becomes increasingly challenging in imaging environments with high MB concentrations and low signal-to-noise ratios, making it difficult to differentiate and localize individual MBs. Recent developments in deep learning (DL) have demonstrated significant improvements over conventional methods but depend on vast amounts of realistic training data with the corresponding ground truth labels, which are difficult to obtain. The alternative, simulated data, in turn, poses challenges in generalizability of the method. In this work, we present a hybrid pipeline for ULM that comprises data generation, localization, and tracking. It combines the current state-of-the-art, utilizing both conventional and DL techniques. We show that using this approach, we can create high-quality velocity maps while being able to generalize well across different domains.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","ImPhys/Imaging Physics","ImPhys/Medical Imaging","","",""
"uuid:76e7e236-66c8-493b-959c-543c57ae2175","http://resolver.tudelft.nl/uuid:76e7e236-66c8-493b-959c-543c57ae2175","More is Better (Mostly): On the Backdoor Attacks in Federated Graph Neural Networks","Xu, J. (TU Delft Cyber Security); Wang, R. (TU Delft Cyber Security); Koffas, S. (TU Delft Cyber Security); Liang, K. (TU Delft Cyber Security); Picek, S. (TU Delft Cyber Security; Radboud Universiteit Nijmegen)","","2022","Graph Neural Networks (GNNs) are a class of deep learning-based methods for processing graph domain information. GNNs have recently become a widely used graph analysis method due to their superior ability to learn representations for complex graph data. Due to privacy concerns and regulation restrictions, centralized GNNs can be difficult to apply to data-sensitive scenarios. Federated learning (FL) is an emerging technology developed for privacy-preserving settings when several parties need to train a shared global model collaboratively. Although several research works have applied FL to train GNNs (Federated GNNs), there is no research on their robustness to backdoor attacks.
This paper bridges this gap by conducting two types of backdoor attacks in Federated GNNs: centralized backdoor attacks (CBA) and distributed backdoor attacks (DBA). Our experiments show that the DBA attack success rate is higher than CBA in almost all cases. For CBA, the attack success rate of all local triggers is similar to the global trigger, even if the training set of the adversarial party is embedded with the global trigger. To explore the properties of two backdoor attacks in Federated GNNs, we evaluate the attack performance for a different number of clients, trigger sizes, poisoning intensities, and trigger densities. Finally, we explore the robustness of DBA and CBA against two state-of-the-art defenses. We find that both attacks are robust against the investigated defenses, necessitating the need to consider backdoor attacks in Federated GNNs as a novel threat that requires custom defenses.","backdoor attacks; graph neural networks; federated learning","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Cyber Security","","",""
"uuid:912200fa-230e-447f-92e8-8ff01bad07c4","http://resolver.tudelft.nl/uuid:912200fa-230e-447f-92e8-8ff01bad07c4","CamPressID: Optimizing Camera Configuration and Finger Pressure for Biometric Authentication","Wang, Weizheng (TU Delft Embedded Systems); Vette, Marek (Student TU Delft); Wang, Q. (TU Delft Embedded Systems); Yang, J. (TU Delft Web Information Systems); Zuniga, Marco (TU Delft Embedded Systems)","Ceballos, Cristina (editor)","2022","To protect sensitive information on smartphones, state-of-the-art (SoA) studies exploit the built-in camera to capture PPG signals from fingertips as a hard-to-forge biometric. However, those studies do not provide a comprehensive analysis to optimize the camera parameters and finger pressure, leading to distorted and unstable PPG signals that degrade the authentication performance. To overcome these limitations, we propose the CamPressID framework. First, we analyze various camera parameters and optimize their configuration to obtain PPG signals with a high signal-to-noise ratio. Second, we investigate different finger pressures to identify the best pressure for every subject, in order to avoid signal distortion. To evaluate the performance of CamPressID, we collect a diverse dataset with 58 subjects. Our evaluation results show that CamPressID can improve the average balanced accuracy (BAC) by 10%. Moreover, the BAC reaches 90%, which is similar to the accuracy reported in the SoA using a dedicated PPG sensor for authentication.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Embedded Systems","","",""
"uuid:586b417c-112a-4176-b36e-1bbe5b4da23d","http://resolver.tudelft.nl/uuid:586b417c-112a-4176-b36e-1bbe5b4da23d","Harmonic Emission Modelling of Electric Vehicle Chargers","Liang, Y. (TU Delft DC systems, Energy conversion & Storage); Wang, L. (TU Delft DC systems, Energy conversion & Storage); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2022","In emerging fast-charging stations, DC fast chargers (DCFCs) are employed which rely on power electronics and control to achieve the required performance. Harmonic emission induced by the complex system behavior is of great concern in the DCFC system. This paper proposes a harmonic emission model for the typical electric vehicle charger design, i.e., two-level active front end. The technique is based on the Fourier series method and the impedance model which is able to reveal the harmonic current emission of DCFCs under different grid conditions. Time-domain simulations are presented subsequently to validate the proposed model.","DC fast charger; Fourier series; harmonics; impedance model","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-06-05","","","DC systems, Energy conversion & Storage","","",""
"uuid:76884511-1a24-467b-8ff7-9a8d0e2c78c8","http://resolver.tudelft.nl/uuid:76884511-1a24-467b-8ff7-9a8d0e2c78c8","A 2m-Range 711uW Body Channel Communication Transceiver Featuring Dynamically-Sampling Bias-Free Interface Front End","Gu, Guanjie (Zhejiang University); Yang, Changgui (Zhejiang University); Li, Zhuhao (Zhejiang University); Feng, Xiangdong (Zhejiang University); Chang, Ziyi (Zhejiang University); Wang, Ting-Hsun (Zhejiang University); Zhang, Yunshan (Zhejiang University); Luo, Yuxuan (Zhejiang University); Zhang, Hong (Zhejiang University); Wang, Ping (Zhejiang University); Du, S. (TU Delft Electronic Instrumentation); Chen, Yong (University of Macau); Zhao, Bo (Zhejiang University)","","2022","Body Channel Communication (BCC) offers a low-loss signal transmission medium for ultra-low-power wearable devices on human body [1]. However, the effective communication range on human body is limited to less than 1m in the state-of-the-art BCC transceivers [2], where the signal loss at the interface of body surface and BCC receiver remains to be one of the main bottlenecks. The limited communication range has blocked the popularization in many WBAN applications, such as signal transmission from to an intelligent insole to smart watch [3]. Relative to the high impedance of human body [4], the lower input impedance of BCC receiver induces significant signal loss. To reduce the interface loss, conventional interface front end (IFE) of BCC receivers was designed to be with a high input impedance [5], but the DC voltage bias decreased both the input impedance and signal gain of IFE.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Instrumentation","","",""
"uuid:bd84cc7a-b0bc-4590-8d50-3639db49f263","http://resolver.tudelft.nl/uuid:bd84cc7a-b0bc-4590-8d50-3639db49f263","An Adaptive Cyber Security Scheme for AC Microgrids","Xiao, J. (TU Delft DC systems, Energy conversion & Storage); Wang, L. (TU Delft DC systems, Energy conversion & Storage); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2022","Distributed secondary control is deemed necessary to restore the state of AC micro-grids to set points. However, for its limited global information, the power electronic system is vulnerable to cyber-attacks that aim to desynchronize converters or even cause a shutdown of micro-grids by unnecessarily triggering the protection schemes. To this end, an adaptive communication weight update for the secondary control layer is proposed. It guarantees frequency synchronization and active power sharing despite the presence of these attacks. Moreover, it automatically dispatches optimal communication lines when all its neighboring data are corrupted to different levels. Finally, the efficacy of the proposed resilient control method is demonstrated using simulations.","AC micro-grid; adaptive control; cyber-attack; distributed control","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-06-05","","","DC systems, Energy conversion & Storage","","",""
"uuid:e72df6c0-b61a-460b-af77-86822adaa574","http://resolver.tudelft.nl/uuid:e72df6c0-b61a-460b-af77-86822adaa574","Detection of cyber attack in smart grid: A Comparative Study","Xiao, J. (TU Delft DC systems, Energy conversion & Storage); Wang, L. (TU Delft DC systems, Energy conversion & Storage); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2022","Smart grid steady control relies heavily on the communication infrastructure among sensors, actuators, and control systems, which makes it vulnerable to cyber-attacks. Accurate acquisition of dynamic state information is deemed vital for efficient detection of these cyber-attacks on a smart grid. However, several popular state estimation methods at the present stage are restricted in practical use and require some assumptions. In this paper, we investigate the security of smart grid systems. We (1) identify and define the security problem in the smart grid, (2) compare the performance of several state estimate methods including Least Square, Kalman filter, Extend Kalman filter, in identifying smart grid dynamic information using measurements, and (3) investigate the Chi-square detector, Euclidean Distance, and Cosine similarity matching approaches for attack detection.","Cyber attack detection; Kalman filter; smart grid; State estimate","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-06-05","","","DC systems, Energy conversion & Storage","","",""
"uuid:dfdbe1ab-b281-496d-9fd3-e0e56ab1a533","http://resolver.tudelft.nl/uuid:dfdbe1ab-b281-496d-9fd3-e0e56ab1a533","Predicting European cities’ climate mitigation performance using machine learning","Hsu, Angel (University of North Carolina at Chapel Hill); Wang, Xuewei (University of North Carolina at Chapel Hill); Tan, Jonas (Yale-NUS College); Toh, Wayne (Yale-NUS College); Goyal, N. (TU Delft Organisation & Governance)","","2022","Although cities have risen to prominence as climate actors, emissions’ data scarcity has been the primary challenge to evaluating their performance. Here we develop a scalable, replicable machine learning approach for evaluating the mitigation performance for nearly all local administrative areas in Europe from 2001-2018. By combining publicly available, spatially explicit environmental and socio-economic data with self-reported emissions data from European cities, we predict annual carbon dioxide emissions to explore trends in city-scale mitigation performance. We find that European cities participating in transnational climate initiatives have likely decreased emissions since 2001, with slightly more than half likely to have achieved their 2020 emissions reduction target. Cities who report emissions data are more likely to have achieved greater reductions than those who fail to report any data. Despite its limitations, our model provides a replicable, scalable starting point for understanding city-level climate emissions mitigation performance.","","en","journal article","","","","","","","","","","","Organisation & Governance","","",""
"uuid:0844ada1-0d6c-44a5-a191-227cc4ecdc10","http://resolver.tudelft.nl/uuid:0844ada1-0d6c-44a5-a191-227cc4ecdc10","On resonances and transverse and longitudinal oscillations in a hoisting system due to boundary excitations","Wang, J. (TU Delft Mathematical Physics; Tianjin Normal University, Tianjin); van Horssen, W.T. (TU Delft Mathematical Physics)","","2022","In this paper, we study transverse and longitudinal oscillations and resonances in a hoisting system induced by boundary disturbances. The dynamics can be described by an initial-boundary value problem for a coupled system of nonlinear wave equations on a slowly time-varying spatial domain. It will be shown how the boundary excitations and the nonlinear terms influence transverse and longitudinal vibrations of the system. Firstly, due to the slow variation of the cable length, a singular perturbation problem arises. By using an interior layer analysis, many resonance manifolds are detected. Secondly, it will be shown that resonances in the system are caused not only by boundary disturbances but also by nonlinear interactions. Based on these observations, a three-timescales perturbation method is used to approximate the solution of the initial-boundary value problem analytically. It turns out that for special frequencies in the boundary excitations and for certain parameter values of the longitudinal stiffness and the conveyance mass, many oscillation modes jump up from small to large amplitudes in the transverse and longitudinal directions. Finally, numerical simulations are presented to verify the obtained analytical results.","Interior layer analysis; Multiple-timescales perturbation method; Nonlinear interactions; Resonance zone; Vertically moving string","en","review","","","","","","","","","","","Mathematical Physics","","",""
"uuid:77462a13-79c1-46a4-9669-9193ff673d73","http://resolver.tudelft.nl/uuid:77462a13-79c1-46a4-9669-9193ff673d73","N24News: A New Dataset for Multimodal News Classification","Wang, Zhen (Student TU Delft); Shan, X. (TU Delft Water Resources); Zhang, Xiangxie (Student TU Delft); Yang, J. (TU Delft Web Information Systems)","Calzolari, Nicoletta (editor); Bechet, Frederic (editor); Blache, Philippe (editor); Choukri, Khalid (editor); Cieri, Christopher (editor); Declerck, Thierry (editor); Goggi, Sara (editor); Isahara, Hitoshi (editor); Maegaard, Bente (editor); Mariani, Joseph (editor); Mazo, Helene (editor); Odijk, Jan (editor); Piperidis, Stelios (editor)","2022","Current news datasets merely focus on text features on the news and rarely leverage the feature of images, excluding numerous essential features for news classification. In this paper, we propose a new dataset, N24News, which is generated from New York Times with 24 categories and contains both text and image information in each news. We use a multitask multimodal method and the experimental results show multimodal news classification performs better than text-only news classification. Depending on the length of the text, the classification accuracy can be increased by up to 8.11%. Our research reveals the relationship between the performance of a multimodal classifier and its sub-classifiers, and also the possible improvements when applying multimodal in news classification. N24News is shown to have great potential to prompt the multimodal news studies.","Multimodal Dataset; News Article; Text Classification","en","conference paper","European Language Resources Association (ELRA)","","","","","","","","","","Water Resources","","",""
"uuid:024b5acb-287e-4fcb-8c5b-a8f8891ed75d","http://resolver.tudelft.nl/uuid:024b5acb-287e-4fcb-8c5b-a8f8891ed75d","Predicting traction return current in electric railway systems through physics-informed neural networks","Kapoor, T. (TU Delft Railway Engineering); Wang, H. (TU Delft Railway Engineering); Nunez, Alfredo (TU Delft Railway Engineering); Dollevoet, R.P.B.J. (TU Delft Railway Engineering)","Ishibuchi, Hisao (editor); Kwoh, Chee-Keong (editor); Tan, Ah-Hwee (editor); Srinivasan, Dipti (editor); Miao, Chunyan (editor); Trivedi, Anupam (editor); Crockett, Keeley (editor)","2022","This paper addresses the problem of determining the distribution of the return current in electric railway traction systems. The dynamics of traction return current are simulated in all three space dimensions by informing the neural networks with the Partial Differential Equations (PDEs) known as telegraph equations. In addition, this work proposes a method of choosing optimal activation functions for training the physics-informed neural network to solve higher-dimensional PDEs. We propose a Monte Carlo based framework to choose the activation function in lower dimensions, mitigating the need for ensemble training in higher dimensions. To further strengthen the applicability of the Monte Carlo based framework, experiments are presented under two loss functions governed by L2 and L∞ norms. The presented method efficiently simulates the traction return current for electric railway systems, even for three-dimensional problems.","Traction return current; electric railway systems; physics-informed neural networks; Monte Carlo; activation functions","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-30","","","Railway Engineering","","",""
"uuid:04251832-8ca4-4137-a42c-7eee041fef5f","http://resolver.tudelft.nl/uuid:04251832-8ca4-4137-a42c-7eee041fef5f","Case Study of the Largest Concrete Earth Pressure Balance Pipe-Jacking Project in the World","Jiang, Xi (Tongji University; The University of Tennessee Knoxville); Zhang, X. (TU Delft Geo-engineering); Wang, Shuai (Shanghai Road and Bridge (Group) Co.,Ltd.); Bai, Yun (Tongji University); Huang, Baoshan (The University of Tennessee Knoxville)","","2022","Pipe jacking has been the dominant trenchless technology for constructing small (\2 m) to medium-diameter (\4 m) tunnels. Uncertainties and construction difficulties increase significantly when the diameter of the tunnel exceeds 4 m. This paper presents a case study of the largest concrete pipe-jacking tunnel project in the world, the sewerage tunnel along Jinshan Lake, Zhenjiang, China. In this project, an underwater tunnel with a diameter of 4.67 m was constructed by the earth pressure balance (EPB) pipe-jacking method. The case study reports project background, and geological and hydrogeology conditions. The key techniques such as the selection of pipe-jacking machine, jacking force estimation and control, design of intermediate jacking station, grouting process control, launching, and reception of the tunnel boring machine, trajectory control of pipe jacking, and ventilation and gas monitoring during the construction period were investigated and discussed. Furthermore, to overcome the technical difficulties associated with the oversized jacked tunnel, the corresponding countermeasures were adopted point by point, so that the safety of the whole project could be guaranteed. This study filled the knowledge gap of technical know-how for large-diameter (over 4.5 m) pipe-jacking tunnel and is expected to provide practical guide for future large-diameter pipe-jacking tunnels.","Grouting; Infrastructure; Lining; Pipe jacking; Tunnels and underground structures","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Geo-engineering","","",""
"uuid:dd2761fa-5009-4dc3-92a0-a5b12f7fe2e8","http://resolver.tudelft.nl/uuid:dd2761fa-5009-4dc3-92a0-a5b12f7fe2e8","Hydrogenated Boron Phosphide THz-Metamaterial-Based Biosensor for Diagnosing COVID-19: A DFT Coupled FEM Study","Tan, C. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology); Wang, S. (TU Delft Bio-Electronics; Southern University of Science and Technology); Yang, Huiru (Southern University of Science and Technology); Huang, Qianming (Southern University of Science and Technology); Li, Shizhen (Southern University of Science and Technology); Liu, X. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology); Ye, H. (Southern University of Science and Technology); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2022","Recent reports focus on the hydrogenation engineering of monolayer boron phosphide and simultaneously explore its promising applications in nanoelectronics. Coupling density functional theory and finite element method, we investigate the bowtie triangle ring microstructure composed of boron phosphide with hydrogenation based on structural and performance analysis. We determine the carrier mobility of hydrogenated boron phosphide, reveal the effect of structural and material parameters on resonance frequencies, and discuss the variation of the electric field at the two tips. The results suggest that the mobilities of electrons for hydrogenated BP monolayer in the armchair and zigzag directions are 0.51 and 94.4 cm2·V−1·s−1, whereas for holes, the values are 136.8 and 175.15 cm2·V−1·s−1. Meanwhile, the transmission spectra of the bowtie triangle ring microstructure can be controlled by adjusting the length of the bowtie triangle ring microstructure and carrier density of hydrogenated BP. With the increasing length, the transmission spectrum has a red-shift and the electric field at the tips of equilateral triangle rings is significantly weakened. Furthermore, the theoretical sensitivity of the BTR structure reaches 100 GHz/RIU, which is sufficient to determine healthy and COVID-19-infected individuals. Our findings may open up new avenues for promising applications in the rapid diagnosis of COVID-19.","hydrogenated boron phosphide monolayer; terahertz metamaterial; bowtie triangle ring microstructure; COVID-19 diagnosis","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:bfd57b52-37cd-4955-90af-56dec2c8a8b7","http://resolver.tudelft.nl/uuid:bfd57b52-37cd-4955-90af-56dec2c8a8b7","High-Enthalpy Geothermal Simulation with Continuous Localization in Physics","Wang, Y. (TU Delft Reservoir Engineering); Voskov, D.V. (TU Delft Reservoir Engineering)","","2022","Simulation of heat production in high-enthalpy geothermal systems is associated with a complex physical process in which cold water invades steam-saturated control volumes. The fully implicit, fully coupled numerical strategy is commonly adopted to solve the governing system composed of mass and energy conservation equations. A conventional nonlinear solver is generally challenged by the strong nonlinearity present during phase transition because of a huge contrast of thermodynamics between hot steam and cool water. In the process of solution, due to the steam condensation, the reduction in fluid volume reduces the pressure in the control volume. This generates multiple local minima in the physical parameter space, which indicates the Newton initial guess should be carefully selected to guarantee the nonlinear convergence. Otherwise, the Newton iteration will approach a local minimum and the solution based on Newton’s update cannot converge and needs to be repeated for a smaller timestep. This problem brings simulation to the stalling behavior where a nonlinear solver wastes a lot of computations and performs at a very small timestep. To tackle this problem, we formulated continuous localization of Newton’s method based on an Operator-Based Linearization (OBL) approach. In OBL, the physical space can be parameterized in terms of operators with supporting points at different levels of resolution. During the simulation, the operator values at supporting points are obtained through reference physics and the remaining part of the space is interpolated. In this way, the nonlinear physical parameter space can be flexibly characterized with different degrees of accuracy. In our proposed approach, the nonlinear Newton iterations are performed in parameter space with different resolutions from coarse to fine. Specifically, the Newton solution under coarser resolution is taken as the initial guess for that under finer resolution. A coarser parameter space represents more linear physics, under which the nonlinear solver quickly converges to a localized solution near the true solution. With refinement in physics, the Newton iteration will approach the true solution and the stalling behaviour in the simulation is avoided. Therefore, a larger timestep can be utilized in the simulation compared with the conventional nonlinear solvers.","continuous localization in physics; high-enthalpy geothermal reservoir; negative compressibility; numerical simulation","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:92e73e76-4dd8-4cb2-85ab-6a96a40b13c1","http://resolver.tudelft.nl/uuid:92e73e76-4dd8-4cb2-85ab-6a96a40b13c1","Mixed-Integer Nonlinear Programming for Energy-Efficient Container Handling: Formulation and Customized Genetic Algorithm","Xin, J. (Zhengzhou University); Meng, Chuang (Zhengzhou University); D'Ariano, Andrea (University of Roma Tre); Wang, Dongshu (Zhengzhou University); Negenborn, R.R. (TU Delft Transport Engineering and Logistics)","","2022","Energy consumption is expected to be reduced while maintaining high productivity for container handling. This paper investigates a new energy-efficient scheduling problem of automated container terminals, in which quay cranes (QCs) and lift automated guided vehicles (AGVs) cooperate to handle inbound and outbound containers. In our scheduling problem, operation times and task sequences are both to be determined. The underlying optimization problem is mixed-integer nonlinear programming (MINLP). To deal with its computational intractability, a customized and efficient genetic algorithm (GA) is developed to solve the studied MINLP problem, and lexicographic and weighted-sum strategies are further considered. An $\epsilon $ -constraint algorithm is also developed to analyze the Pareto frontiers. Comprehensive experiments are tested on a container handling benchmark system, and the results show the effectiveness of the proposed lexicographic GA, compared to results obtained with two commonly-used metaheuristics, a commercial MINLP solver, and two state-of-the-art methods.","Automated container terminals; Containers; Cranes; Energy consumption; energy efficiency; genetic algorithm.; Genetic algorithms; Job shop scheduling; mixed-integer nonlinear programming; Optimization; Task analysis","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Transport Engineering and Logistics","","",""
"uuid:b7ebe186-eaef-43df-8849-ba812bf2b3a1","http://resolver.tudelft.nl/uuid:b7ebe186-eaef-43df-8849-ba812bf2b3a1","Highly dispersed Cd cluster supported on TiO2 as an efficient catalyst for CO2 hydrogenation to methanol","Wang, J. (Chinese Academy of Science); Meeprasert, J. (TU Delft ChemE/Inorganic Systems Engineering); Han, Z. (Chinese Academy of Science; Nankai University); Wang, H. (Chinese Academy of Science); Feng, Z. (University of Chinese Academy of Sciences; Chinese Academy of Science); Tang, C. (University of Chinese Academy of Sciences; Chinese Academy of Science); Sha, F. (Chinese Academy of Sciences; Nankai University); Tang, S. (University of Chinese Academy of Sciences; Chinese Academy of Science); Pidko, E.A. (TU Delft ChemE/Inorganic Systems Engineering)","","2022","The conversion of CO2 with high activity and high selectivity to methanol remains challenging because of both the kinetics and thermodynamics difficulties associated with the chemical reactivity of CO2. Herein, we report a new catalyst of Cd/TiO2 enabling 81% methanol selectivity at 15.8% CO2 conversion with the CH4 selectivity below 0.7%. The combination of experimental and computational studies show that the unique electronic properties of Cd cluster supported on TiO2 are responsible for the high selectivity for CO2 hydrogenation to methanol via a HCOO* pathway realized at the interface catalytic sites.","CO2 hydrogenation; methanol; Cd/TiO2","en","journal article","","","","","","","","","","","ChemE/Inorganic Systems Engineering","","",""
"uuid:4e64e552-8af5-415a-b990-129d823c9e53","http://resolver.tudelft.nl/uuid:4e64e552-8af5-415a-b990-129d823c9e53","Review on Power Quality Issues in EV Charging","Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Wang, L. (TU Delft DC systems, Energy conversion & Storage); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2022","Electric vehicles (EVs) are playing a crucial role in achieving the carbon neutral goal. To make the charging experience comparable with the refueling of the gasoline cars, more and more chargers are installed and connected to the grid. Meanwhile, the charging power is going up. As a result, more and more power quality issues associated with EV charging events have already been reported. In this paper, the power quality issues that are relevant to EV charging, including flicker, harmonics, and supraharmonics, are summarized. Their generation mechanisms, harm to the grid, and the promising mitigation measures are discussed. Case studies are also done to mimic the power quality issues in EV charging, and verify the analysis.","Power Quality; EV Cahrging; Harmonics; voltage fluctuations; Power electronic converter","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-06-05","","","DC systems, Energy conversion & Storage","","",""
"uuid:5fc63aa1-ad14-4344-8cae-193eac1928a8","http://resolver.tudelft.nl/uuid:5fc63aa1-ad14-4344-8cae-193eac1928a8","Large Region Targets Observation Scheduling by Multiple Satellites Using Resampling Particle Swarm Optimization","Gu, Yi (Beihang University); Han, Chao (Beihang University); Chen, Yuhan (China Satellite Network Innovation Company, Ltd.); Liu, Shenggang (Beihang University); Wang, X. (TU Delft Learning & Autonomous Control; Queen Mary University of London)","","2022","The last decades have witnessed a rapid increase of Earth observation satellites (EOSs), leading to the increasing complexity of EOSs scheduling. On account of the widespread applications of large region observation, this article aims to address the EOSs observation scheduling problem for large region targets. A rapid coverage calculation method employing a projection reference plane and a polygon clipping technique is first developed. We then formulate a nonlinear integer programming model for the scheduling problem, where the objective function is calculated based on the developed coverage calculation method. A greedy initialization-based resampling particle swarm optimization (GI-RPSO) algorithm is proposed to solve the model. The adopted greedy initialization strategy and particle resampling method contribute to generating efficient and effective solutions during the evolution process. In the end, extensive experiments are conducted to illustrate the effectiveness and reliability of the proposed method. Compared to the traditional PSO and the widely used greedy algorithm, the proposed GI-RPSO can improve the scheduling result by 5.42% and 15.86%, respectively.","Large region targets; multiple satellites; observation scheduling; resampling particle swarm optimization (PSO)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-03-12","","","Learning & Autonomous Control","","",""
"uuid:526873f8-0696-4610-83b1-98a6836e8b6a","http://resolver.tudelft.nl/uuid:526873f8-0696-4610-83b1-98a6836e8b6a","A 10-mV-Startup-Voltage Thermoelectric Energy Harvesting System With a Piezoelectric Starter","Wang, Ruizhi (Student TU Delft); Liang, Yansong (Student TU Delft); Du, S. (TU Delft Electronic Instrumentation)","","2022","An ultra-low-startup-voltage thermoelectric energy harvesting system assisted by a piezoelectric generator (PEG) is presented in this paper. When the energy harvesting system is implemented in a place where there is mechanical vibration, the associated PEG can generate a stable clock signal and drive the boost converter to start from the cold state even at extremely low thermoelectric generator (TEG) voltage. The proposed system is designed and simulated in a 180-nm BCD process. The simulations show that the proposed system can start the TEG system from the cold state from as low as 10 mV of TEG voltage while keeping a 63.9% efficiency. The peak power conversion efficiency is achieved at 74.9% when the TEG voltage is 50 mV.","Thermoelectric energy harvesting; piezoelectric generator; cold-startup; maximum power point tracking","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Instrumentation","","",""
"uuid:05e2851b-a726-4357-a96c-8a4b00e60873","http://resolver.tudelft.nl/uuid:05e2851b-a726-4357-a96c-8a4b00e60873","CardioID: Mitigating the Effects of Irregular Cardiac Signals for Biometric Identification","Wang, Weizheng (TU Delft Embedded Systems); Wang, Q. (TU Delft Embedded Systems); Zuniga, Marco (TU Delft Embedded Systems)","","2022","Cardiac patterns are being used to obtain hard-to-forge biometric signatures and have led to high accuracy in state-of-the-art (SoA) identification applications. However, this performance is obtained under controlled scenarios where cardiac signals maintain a relatively uniform pattern, facilitating the identification process. In this work, we analyze cardiac signals collected in more realistic (uncontrolled) scenarios and show that their high signal variability (i.e., ir-regularity) makes it harder to obtain stable and distinct user features. Furthermore, SoA usually fails to identify specific groups of users, rendering existing identification methods futile in uncontrolled scenarios. To solve these problems, we propose a framework with three novel properties. First, we design an adaptive method that achieves stable and distinct features by tailoring the filtering spectrum to each user. Second, we show that users can have multiple cardiac morpholo-gies, offering us a much bigger pool of cardiac signals and users compared to SoA. Third, we overcome other distortion effects present in authentication applications with a multi-cluster approach and the Mahalanobis distance. Our evaluation shows that the average balanced accuracy (BAC) of SoA drops from above 90% in controlled scenarios to 75% in uncontrolled ones, while our method maintains an average BAC above 90% in uncontrolled scenarios.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Embedded Systems","","",""
"uuid:5c6513c3-32d3-41fb-8b8e-a5e591a3218f","http://resolver.tudelft.nl/uuid:5c6513c3-32d3-41fb-8b8e-a5e591a3218f","Embodied airflow sensing for improved in-gust flight of flapping wing MAVs","Wang, C. (TU Delft Aerospace Engineering); Wang, S. (TU Delft Control & Simulation); de Croon, G.C.H.E. (TU Delft Control & Simulation); Hamaza, S. (TU Delft Control & Simulation)","","2022","Flapping wing micro aerial vehicles (FWMAVs) are known for their flight agility and maneuverability. These bio-inspired and lightweight flying robots still present limitations in their ability to fly in direct wind and gusts, as their stability is severely compromised in contrast with their biological counterparts. To this end, this work aims at making in-gust flight of flapping wing drones possible using an embodied airflow sensing approach combined with an adaptive control framework at the velocity and position control loops. At first, an extensive experimental campaign is conducted on a real FWMAV to generate a reliable and accurate model of the in-gust flight dynamics, which informs the design of the adaptive position and velocity controllers. With an extended experimental validation, this embodied airflow-sensing approach integrated with the adaptive controller reduces the root-mean-square errors along the wind direction by 25.15% when the drone is subject to frontal wind gusts of alternating speeds up to 2.4 m/s, compared to the case with a standard cascaded PID controller. The proposed sensing and control framework improve flight performance reliably and serve as the basis of future progress in the field of in-gust flight of lightweight FWMAVs.","flapping wing MAV; bio-inspired sensing; adaptive control; in-gust flight; onboard airflow sensing","en","journal article","","","","","","","","","Aerospace Engineering","","Control & Simulation","","",""
"uuid:cc200968-8632-46cf-9b6c-63eaf76fba24","http://resolver.tudelft.nl/uuid:cc200968-8632-46cf-9b6c-63eaf76fba24","A Weekly Diary Study on Playful Study Design, Study Engagement, and Goal Attainment: The Role of Proactive Personality","Wang, Huatian (Lingnan University, Hong Kong; Eindhoven University of Technology); Ren, Yue (Qingdao University of Technology); Liu, W. (TU Delft Design Conceptualization and Communication)","","2022","Students’ learning processes are heavily impeded by the COVID-19 pandemic. Students are experiencing more online learning environment and less face-to-face idea exchange, which may make them feel exhausted and demotivated. Using self-determination and proactivity theories, we propose and examine whether playful study design (PSD)—a proactive study strategy including designing fun and designing competition in learning tasks—is effective in fostering study engagement, which, in turn, improves study goal attainment during the COVID-19 period. Moreover, we examine whether students who are high in proactive personality will benefit more (e.g., reach a higher level of study engagement) when using the PSD strategy. We collected data using a weekly diary approach during four consecutive weeks, including 97 people and 308 within-person observations. Results of multilevel analyses showed that weekly PSD was positively related to weekly study engagement, and in turn, facilitated weekly goal attainment. Moreover, we found that proactive personality moderated and strengthened the positive associations between PSD and goal attainment, study engagement and goal attainment, but not for the relationship between PSD and study engagement. Overall, we provide one of the first attempts to demonstrate how PSD strategy can be used in student study life to improve study engagement and reach their goals. We shed light on how proactive personality can safeguard the success of PSD strategy. Theoretical and practical contributions are discussed.","Diary study; Goal attainment; Playful study design; Proactive personality; Study engagement","en","journal article","","","","","","","","","","","Design Conceptualization and Communication","","",""
"uuid:75604cc8-d7e7-47c9-a2e1-66849441ae08","http://resolver.tudelft.nl/uuid:75604cc8-d7e7-47c9-a2e1-66849441ae08","基于地理分级标准的偏远地区卫生人力资源优化:澳大利亚改良版蒙纳士模型及其对我国的启示","Gan, Y.Y. (TU Delft History, Form & Aesthetics); Wang, Shuping (China National Health Development Research Center, beijing); Wu, Xiaofan (Shihezi University); Yan, Lina (China National Health Development Research Center, beijing)","","2022","In Australia,28% of the population live in remote and rural areas,where they face many health service utilization challenges due to geographical conditions,and generally have lower health status than those living in coastal metropolitan areas. To address the challenges of accessing health services in remote and rural areas,the Australian Government Department of Health and Aged Care has introduced a geographical classification system to help healthcare providers to improve healthcare services since 1994,and regularly updated the system to adapt to the latest sociodemographic and healthcare status,as well as formulated a range of complementary health policies to support rural and remote areas. From 2018,Australian Government Department of Health and Aged Care has adopted a new classification standard,the Modified Monash Model. We reviewed Australia's practices and concluded that,to better deliver high-quality and accessible healthcare services to areas with weak healthcare resources in China,Australia's experience could be used for reference,during taking actions to promote and refine the geographic classification system for healthcare services in a timely manner,formulating policies supporting the enhancement of access to health workers systematically,and taking advantage of modern,high and new technologies.","Australia; Geographical classification; Health equity; Health policy; Health services accessibility; Resource allocation; Rural and remote areas; Rural health","zh","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","History, Form & Aesthetics","","",""
"uuid:06f907ea-7cbb-46bb-863f-87229532e41c","http://resolver.tudelft.nl/uuid:06f907ea-7cbb-46bb-863f-87229532e41c","A Ring-Oscillator Sub-Sampling PLL With Hybrid Loop Using Generator-Based Design Flow","Wang, Zhongkai (University of California); Choi, Minsoo (Samsung Semiconductor); Wright, John (University of California); Lee, Kyoungtae (University of California); Liu, Zhaokai (University of California); Yin, Bozhi (University of California); Han, Jaeduk (Hanyang University); Du, S. (TU Delft Electronic Instrumentation); Alon, Elad (University of California)","","2022","We present a ring-oscillator-based sub-sampling phase-locked loop (PLL) using a generator-based design flow. A hybrid loop with a delta-sigma ($\Delta \Sigma$) modulator is applied to reduce the loop filter (LF) area and the control ripple. The generator automatically produces the ring oscillator and PLL to meet the provided specifications. The 10-GHz PLL instance implemented in 28-nm planar process achieves RMS jitter of}299.5 fs and power of 9.9 mW from a 1-V supply.","PLL; sub-sampling; ring oscillator; hybrid; PLL generator","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Instrumentation","","",""
"uuid:60df9a09-c590-499b-a752-6d0c4de4cc94","http://resolver.tudelft.nl/uuid:60df9a09-c590-499b-a752-6d0c4de4cc94","A PV-assisted 10-mV Startup Boost Converter for Thermoelectric Energy Harvesting","Liang, Yansong (Student TU Delft); Wang, Ruizhi (Student TU Delft); Chen, Zhongsheng (Hunan University of Science and Technology); Du, S. (TU Delft Electronic Instrumentation)","","2022","This paper presents a boost converter for thermo-electric energy harvesting with photovoltaic (PV)-assisted startup. The converter employs a new two-phase startup architecture and the PV cell is used in the first phase to provide an initial high voltage for startup. This high voltage drives the boost converter to charge a startup capacitor, which powers the main control block to continue self-startup in phase 2. The proposed system is designed and simulated in a $0.18\mu{\mathrm{m}}$ BCD process. The simulations show successful cold-start from 10 mV thermoelectric voltage. In addition, maximum power point tracking and zero current switching techniques are adopted in the system to achieve 91% peak efficiency. The proposed system can finish the cold-start within 250 ms.","thermoelectric energy harvesting; startup; boost converter","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Instrumentation","","",""
"uuid:f3fdaf77-3236-454e-8f77-5d156cb20c3b","http://resolver.tudelft.nl/uuid:f3fdaf77-3236-454e-8f77-5d156cb20c3b","Cost-efficient anthropomorphic head phantom for quantitative image quality assessment in cone beam CT","Wang, Yichao (Philips Healthcare Nederland); Dankelman, J. (TU Delft Medical Instruments & Bio-Inspired Technology); Ruijters, Danny (Philips Healthcare Nederland)","","2022","In this study, a novel anthropomorphic head phantom for quantitative image quality assessment in cone beam computed tomography (CBCT) is proposed. The phantom is composed of tissue equivalent materials (TEMs) which are suitable for cost-efficient fabrication methods such as silicone casting and 3D printing. A monocalcium phosphate/gypsum mixture (MCPHG), nylon and a silyl modified polymer gel (SMP) are proposed as bone, muscle and brain equivalent materials respectively. The TEMs were evaluated for their radiodensity in terms of Hounsfield Units (HU) and their x-ray scatter characteristics. The median radiodensity and inter quartile range (IQR) of the MCPHG and SMP were found to be within the range of the theoretical radiodensity for bone and brain tissue: 922 (IQR = 156) and 47 (IQR = 7) HU respectively. The median radiodensity of nylon was slightly outside of the HU range of muscle tissue, but within the HU range of a combination of muscle and adipose tissue: −18 (IQR = 40) HU. The median ratios between the measured scatter characteristics and simulated tissues were between 0.84 and 1.13 (IQR between 0.05 and 0.14). The preliminary results of this study show that the proposed design and TEMs are potentially suitable for the fabrication of a cost-efficient anthropomorphic head phantom for quantitative image quality assessment in CT or CBCT.","anthropomorphic head phantom; cone beam computed tomography; image quality assessment; radiodensity; scatter; tissue equivalent materials","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-05-15","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:a9bb4c3f-ad72-4f9e-b8d0-5db1935f6391","http://resolver.tudelft.nl/uuid:a9bb4c3f-ad72-4f9e-b8d0-5db1935f6391","The built environment impacts on route choice from home to school for rural students: A stated preference experiment","Han, Li (Chengdu University of Technology); Wang, Yan (Sichuan College of Architectural Technology); Ao, Yibin (Chengdu University of Technology); Ding, Xuan (Chengdu University of Technology); Li, Mingyang (Chengdu University of Technology); Wang, T. (TU Delft Design & Construction Management)","","2022","Introduction: Rural roads and built environment in China have been developed enormously, but it is not clear whether these roads fulfill the needs of school children as they need to travel long to school every day.
Objective: It is crucial to understand the influencing factors of their travel mode choices to better design future country roads and built environment, aiming to promote physical activities of school children in a safe built environment.
Method: This study thus attempts to explore the impacts of rural built environment attributes on children's school travel mode preferences. Eight rural built environment attributes are considered: distance from home to school; the number of intersections passed on the way to school; whether there are sidewalks/bicycle lanes; the traffic speed of school access routes; whether there are separation facilities between motor vehicles and non-motor vehicles; whether there are traffic lights and zebra crossings; availability of greenery such as lawns, flower ponds and street trees and whether there are shops on the way to school and at the school gate. Six hundred and thirty eight valid questionnaires were obtained through face-to-face interviews with school-age children in villages. A multinomial logit model was estimated to unravel the preferences and choices of rural school-age children in different models of school travel using the stated choice data.
Results: All the eight attributes have significant impacts on rural children's school travel choices on foot, bicycle, electric bicycle or motorbike. And four rural road design attributes have significant effects on rural children's school travel by private cars. A travel path with pavements or bike lanes, few intersections, low traffic speeds, greenery and shops can facilitate children's school travels on foot or by bike. The conclusions can provide reference for the further upgrading planning, designing and construction of rural roads, as well as enriching the theory and practice of child-friendly villages construction.","rural school travel built environment; stated preference survey; school travel; multinomial logit model; experiment","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:e5ab18b8-b317-4d7f-b966-16d29d8ac360","http://resolver.tudelft.nl/uuid:e5ab18b8-b317-4d7f-b966-16d29d8ac360","Geographical spatial analysis and risk prediction based on machine learning for maritime traffic accidents: A case study of Fujian sea area","Yang, Yang (Jimei University; Xiamen Data Intelligence Academy of CAS); Shao, Zheping (Jimei University); Hu, Yu (Xiamen Data Intelligence Academy of CAS); Mei, Qiang (Shanghai Maritime University; Jimei University); Pan, Jiacai (Jimei University); Song, R. (TU Delft Safety and Security Science); Wang, Peng (Shanghai Maritime University; Institute of Computing Technology Chinese Academy of Sciences)","","2022","Safety analysis according to the spatial distribution characteristics of maritime traffic accidents is critical to maritime traffic safety management. An accident analysis framework based on the geographic information system (GIS) is proposed to characterize the spatial distribution of maritime traffic accidents occurring in the Fujian sea area in 2007–2020 by employing kernel density estimation and spatial autocorrelation techniques. The sea area is divided into various grids, and in each grid, the mapping relationships between the number and severity of the traffic accidents and the traffic characteristics are established. Machine learning (ML) technology is used to assess whether a grid area is an accident-prone area and to predict accident severity in each grid. The accident prediction of different ML models, including random forest (RF) model, Adaboost model, gradient boosting decision tree (GBDT) model, and Stacking combined model, were compared. The optimality of the Stacking combined model was verified by comparing the experimental results of this model with those of classical prediction models, convolutional neural network (CNN), long short term memory (LSTM), and support vector machine (SVM). According to the results, the maritime accident data set of the entire Fujian sea area shows typical clustering characteristics and positive spatial correlation. That is, the kernel density estimation indicates that subareas, including the Ningde sea area, Fuzhou sea area, and Xiamen sea area, generally have high densities of maritime accidents and the highest risk value within the whole Fujian sea area. High-high accident clustering, that is high cluster areas neighbored by other areas of high cluster, is mainly seen in the Ningde and Fuzhou sea areas, while the Xiamen, Putian, and Zhangzhou subareas show low-low clustering, which are low clusters neighbored by low clusters. Among the ML models, the Stacking combined model shows high accuracy, precision, recall, and F1-score values of 0.912, 0.910, 0.912, and 0.904 in predicting whether a grid area is an accident-prone area and 0.750, 0.745, 0.750, and 0.746 in predicting the accident severity in the grid, indicating its superior maritime traffic accident prediction performance. Based on our analysis of the distribution characteristics and geospatial data, our proposed method demonstrates effective and reliable risk prediction.","Accident prediction; Fujian sea area; Geographical spatial analysis; Machine learning; Maritime accident","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Safety and Security Science","","",""
"uuid:588d5ca6-5782-4030-979d-a38cb8c567f8","http://resolver.tudelft.nl/uuid:588d5ca6-5782-4030-979d-a38cb8c567f8","Resilience Assessment of Chemical Process Systems under uncertain Disruptions based on Catastrophe Theory (CT) and Dynamic Bayesian Network (DBN)","Sun, H. (TU Delft Safety and Security Science; China University of Petroleum (East China)); Wang, Haiqing (China University of Petroleum (East China)); Yang, M. (TU Delft Safety and Security Science); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Universiteit Antwerpen; Katholieke Universiteit Leuven)","","2022","Due to the rapid development of technology, process systems become dynamic, automated, and complex, resulting in the strong interdependence and interaction among components and ensuring system safety by conventional methods a challenge. Compared with traditional risk assessment methods, resilience assessment is a more appropriate method for ensuring the safety of process systems under uncertain disruptions. Resilience refers to absorbing and adapting to changing conditions and recovering from disruptions. This paper presents a comprehensive assessment model that combines the catastrophe theory (CT) with the dynamic Bayesian network (DBN) to measure dynamic resilience. Firstly, the CT is employed to quantify the intensity of disruptions. Subsequently, the performance response function (PRF) of the system is determined by DBN. A resilience metric is then introduced to measure system resilience under uncertain disruptions. The method is demonstrated through a release prevention barrier system.","","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:cf55be05-abfe-4943-a14f-6b5c8cb96711","http://resolver.tudelft.nl/uuid:cf55be05-abfe-4943-a14f-6b5c8cb96711","A Novel Bilevel False Data Injection Attack Model Based on Pre-and Post-Dispatch","Gao, Shibin (Southwest Jiaotong University); Lei, Jieyu (Southwest Jiaotong University); Wei, Xiaoguang (Southwest Jiaotong University); Liu, Y. (TU Delft Intelligent Electrical Power Grids); Wang, Tao (Xihua University)","","2022","This letter develops a new bilevel optimization model to construct false data injection attack based on pre- and post- dispatch. In order to enhance the attack concealment, the proposed bilevel model can minimize the variation of uploaded measurements between pre- and post-attack before dispatching, after which the attack can lead the system to an uneconomic and insecure operating state after dispatching. Simulation results validate the effectiveness of the proposed bilevel model in term of operating cost and network overloads.","bilevel optimization model; false data injection","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Intelligent Electrical Power Grids","","",""
"uuid:e254f796-cfd1-4c53-a8cb-c716eb4375fa","http://resolver.tudelft.nl/uuid:e254f796-cfd1-4c53-a8cb-c716eb4375fa","Study on vertical vibration and transmission characteristics of railway ballast using impact hammer test","Liu, Ganzhong (Southwest Jiaotong University); Cong, Jianli (Southwest Jiaotong University); Wang, Ping (Southwest Jiaotong University); Du, Shuai (Southwest Jiaotong University); Wang, L. (TU Delft Railway Engineering; Southwest Jiaotong University); Chen, Rong (Southwest Jiaotong University)","","2022","The vertical vibration and transmission characteristics of ballast are key factors that affect the dynamic stability of railway track structures and control the settlement of ballasted beds. Therefore, the following study was conducted to explore this topic. Firstly, through an impact hammer test on a ballast sensor with embedding chip, the vertical vibration data of the ballast was accurately measured. Therefore, the vertical vibration characteristics of a single ballast can be studied. Then, the vertical vibration characteristics at different positions in the stack were obtained by embedding ballast sensors into a ballasted stack. Finally, combined with field tests, a discrete element numerical model was established, then the vibration transmission speed and diffusion angle in a ballasted stack were calculated. The results of this study show that the damping ratio of ballast particles is less than 0.1, and the natural frequency is above 1000 Hz. The damping ratio and natural frequency of ballasts are greatly affected by their shape. The damping ratio of a ballasted stack is greater than that of ballast particles, and its natural frequency is lower. This indicates that the ballasted stack has the attributes of a soft material. The vertical acceleration transmission rate of ballasts is lower at frequencies below 257.94 Hz. This shows that the vibration suppression ability of the ballasted bed is better in the lower frequency range. As the depth increases, the vertical vibration transmission speed of the ballast gradually decreases, as does the accumulated external force. In the impact hammer test of a ballasted box, the average vertical vibration transmission speed was calculated to be 0.88 mm/μs, and the ballast vibration was transmitted downward at a diffusion angle of 35.32°–54.51° from the direction of gravity.","Ballast; Damping; Discrete element; Natural frequency; Transmission; Vibration","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-06-04","","","Railway Engineering","","",""
"uuid:9440f82c-7849-4bce-a409-99a130c4e660","http://resolver.tudelft.nl/uuid:9440f82c-7849-4bce-a409-99a130c4e660","CO_2 Storage in deep saline aquifers: impacts of fractures on hydrodynamic trapping","Wang, Y. (TU Delft Numerical Analysis); Vuik, Cornelis (TU Delft Numerical Analysis); Hajibeygi, H. (TU Delft Reservoir Engineering)","","2022","Natural or induced fractures are typically present in subsurface geological formations. Therefore, they need to be carefully studied for reliable estimation of the long-term carbon dioxide storage. Instinctively, flow-conductive fractures may undermine storage security as they increase the risk of CO2 leakage if they intersect the CO2 plume. In addition, fractures may act as flow barriers, causing significant pressure gradients over relatively small regions near fractures. Nevertheless, despite their high sensitivities, the impact of fractures on the full-cycle storage process has not been fully quantified and understood. In this study, a numerical model is developed and applied to analyze the role of discrete fractures on the flow and transport mechanism of CO2 plumes in simple and complex fracture geometries. A unified framework is developed to model the essential hydrogeological trapping mechanisms. Importantly, the projection-based embedded discrete fracture model is incorporated into the framework to describe fractures with varying conductivities. Impacts of fracture location, inclination angle, and fracture-matrix permeability ratio are systemically studied for a single fracture system. Moreover, the interplay between viscous and gravity forces in such fractured systems is analyzed. Results indicate that the fracture exhibits differing effects regarding different trapping mechanisms. Generally speaking, highly-conductive fractures facilitate dissolution trapping while weakening residual trapping, and flow barriers can assist dissolution trapping for systems with a relatively low gravity number. The findings from the test cases for single fracture geometries are found applicable to a larger-scale domain with complex fracture networks. This indicates the scalability of the study for field-relevant applications.","Compositional simulation; Embedded discrete fracture model; Geologic carbon storage; Multiphase flow in porous media","en","journal article","","","","","","","","","","","Numerical Analysis","","",""
"uuid:7b8b833c-9b76-4855-ae82-2208e18af2e9","http://resolver.tudelft.nl/uuid:7b8b833c-9b76-4855-ae82-2208e18af2e9","Effect of the location pattern of rural residential buildings on natural ventilation in mountainous terrain of central China","Xie, Mingjing (Central South University China); Wang, Yuran (Central South University China); Liu, Zhengxuan (TU Delft Design & Construction Management; Central South University China; Hunan University); Zhang, Guoqiang (Hunan University)","","2022","The use of natural ventilation in buildings to reduce the energy consumption and CO2 emission has been widely investigated and practiced, but few existing studies have considered the exploration and assessment of natural ventilation in different location patterns of rural residential buildings in the mountainous terrain of China. In this paper, the representative rural residential buildings are firstly selected in Huarong, Pingjiang and Liuyang regions of northern Hunan Province to carry out on-site survey works to determine building types, physical parameters and layout forms. Then, the wind tunnel experiments are carried out to investigate the effectiveness of natural ventilation under different location patterns, and the monitored results are compared with simulated data. The results show that the experiments and simulations are in satisfactory agreement. The experimental data also indicate that when the modelled distance of 120 mm (i.e. 12 m between the building and hilly terrain in practical application) is the best option for building natural ventilation. Based on the investigation and statistical data, the natural ventilation effectiveness under different location patterns and operational conditions is simulated using CFD methods, and it is obtained the most favourable location pattern for natural ventilation. The results show that the winter ventilation of buildings in the existing location pattern is significantly obstructed in the hilly terrain, which is favourable to the indoor thermal environment, however, the natural ventilation is compromised to a certain extent in summer. Furthermore, the findings also show that, regardless of the hilly terrain's height at 50 m or 150 m, the buildings are able to avoid natural ventilation in winter to the maximum extent when the distance between the buildings and the frontier of the hilly terrain is double that of the building height (i.e. 12 m). This study could contribute to theoretical instructions for optimum design of natural ventilation of rural residential buildings in the mountainous terrain of central China.","CFD simulation; Hilly terrains; Location pattern; Natural ventilation; Rural residential buildings; Wind tunnel experiment","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:4b73ce15-7c52-4ef9-9729-372c0ca88400","http://resolver.tudelft.nl/uuid:4b73ce15-7c52-4ef9-9729-372c0ca88400","FMCW Radar-Based Hand Gesture Recognition using Spatiotemporal Deformable and Context-Aware Convolutional 5D Feature Representation","Dong, Xichao (Beijing Institute of Technology); Zhao, Zewei (Beijing Institute of Technology); Wang, Yupei (Beijing Institute of Technology); Zeng, Tao (Beijing Institute of Technology); Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Sui, Yi (Beijing Institute of Technology)","","2022","Recently, frequency-modulated continuous-wave (FMCW) radar-based hand gesture recognition (HGR) using deep learning has achieved favorable performance. However, many existing methods use extracted features separately, i.e., using one of the range, Doppler, azimuth, or elevation angle information, or a combination of any two, to train convolutional neural networks (CNNs), which ignore the interrelation among the 5-D time-varying-range-Doppler-azimuth-elevation feature space. Although there have been methods using the 5-D information, their mining of the interrelation among the 5-D feature space is not sufficient, and there is still room for improvements. This article proposes a new processing scheme of HGR based on 5-D feature cubes that are jointly encoded by a 3-D fast Fourier transform (3-D-FFT)-based method. Then, a CNN is proposed by building two novel blocks, i.e., the spatiotemporal deformable convolution (STDC) block and the adaptive spatiotemporal context-aware convolution (ASTCAC) block. Concretely, STDC is designed to cope with hand gestures' large spatiotemporal geometric transformations in the 5-D feature space. Moreover, ASTCAC is designed for modeling long-distance global relationships, e.g., relationships between pixels of the feature at the upper left corner and lower right corner, and exploring the global spatiotemporal context, in order to enhance the target feature representation and suppress interference. Finally, our presented method is verified on a large radar dataset, including 19 760 sets of 16 common hand gestures, collected by 19 subjects. Our method obtains a recognition rate of 99.53% on the validation dataset and that of 97.22% on the test dataset, which is significantly better than state-of-the-art methods.","Azimuth; Convolution; Doppler effect; Estimation; Feature extraction; Frequency-modulated continuous wave (FMCW) radar; hand gesture recognition; spatiotemporal context modeling; spatiotemporal deformable convolution; Spatiotemporal phenomena; Three-dimensional displays","en","journal article","","","","","","","","","","","Microwave Sensing, Signals & Systems","","",""
"uuid:afd99755-5ee1-40b0-abe8-fd88861b8d82","http://resolver.tudelft.nl/uuid:afd99755-5ee1-40b0-abe8-fd88861b8d82","Answer Quality Aware Aggregation for Extractive QA Crowdsourcing","Zhu, P. (TU Delft Web Information Systems); Wang, Z. (TU Delft Mathematical Physics); Yang, J. (TU Delft Web Information Systems); Hauff, C. (TU Delft Web Information Systems); Anand, A. (TU Delft Web Information Systems)","","2022","Quality control is essential for creating extractive question answering (EQA) datasets via crowdsourcing. Aggregation across answers, i.e. word spans within passages annotated, by different crowd workers is one major focus for ensuring its quality. However, crowd workers cannot reach a consensus on a considerable portion of questions. We introduce a simple yet effective answer aggregation method that takes into account the relations among the answer, question, and context passage. We evaluate answer quality from both the view of question answering model to determine how confident the QA model is about each answer and the view of the answer verification model to determine whether the answer is correct. Then we compute aggregation scores with each answer’s quality and its contextual embedding produced by pre-trained language models. The experiments on a large real crowdsourced EQA dataset show that our framework outperforms baselines by around 16% on precision and effectively conduct answer aggregation for extractive QA task.","","en","conference paper","Association for Computational Linguistics (ACL)","","","","","","","","","","Web Information Systems","","",""
"uuid:8414c0b4-0c3b-4d6b-b3c2-08002052deee","http://resolver.tudelft.nl/uuid:8414c0b4-0c3b-4d6b-b3c2-08002052deee","Efficient Jacobian-Based Inverse Kinematics With Sim-to-Real Transfer of Soft Robots by Learning","Fang, G. (TU Delft Materials and Manufacturing); Tian, Yingjun (The University of Manchester); Yang, Zhi Xin (University of Macau); Geraedts, Jo M.P. (TU Delft Mechatronic Design); Wang, C.C. (The University of Manchester)","","2022","This article presents an efficient learning-based method to solve the <italic>inverse kinematic</italic> (IK) problem on soft robots with highly nonlinear deformation. The major challenge of efficiently computing IK for such robots is due to the lack of analytical formulation for either forward or inverse kinematics. To address this challenge, we employ neural networks to learn both the mapping function of forward kinematics and also the Jacobian of this function. As a result, Jacobian-based iteration can be applied to solve the IK problem. A sim-to-real training transfer strategy is conducted to make this approach more practical. We first generate a large number of samples in a simulation environment for learning both the kinematic and the Jacobian networks of a soft robot design. Thereafter, a sim-to-real layer of differentiable neurons is employed to map the results of simulation to the physical hardware, where this sim-to-real layer can be learned from a very limited number of training samples generated on the hardware.","Computational modeling; Hardware; Inverse kinematics (IKs); Jacobian; Jacobian matrices; Kinematics; learning; Numerical models; sim-to-real; Soft robotics; soft robots; Training","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Materials and Manufacturing","","",""
"uuid:a03ab1c9-bc1f-4a62-b1d2-20783b4d60d4","http://resolver.tudelft.nl/uuid:a03ab1c9-bc1f-4a62-b1d2-20783b4d60d4","An online data driven fault diagnosis and thermal runaway early warning for electric vehicle batteries","Sun, S.Z. (TU Delft DC systems, Energy conversion & Storage; Beijing Institute of Technology); Wang, Zhenpo (Beijing Institute of Technology); Liu, Peng (Beijing Institute of Technology); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Chen, Yong; Han, Yang (The University of Manchester); Wang, Peng (Zhejiang Geely Automobile Research Institute Co); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2022","Battery fault diagnosis is crucial for stable, reliable, and safe operation of electric vehicles, especially the thermal runaway early warning. Developing methods for early failure detection and reducing safety risks from failing high energy lithium-ion batteries has become a major challenge for industry. In this article, a real-time early fault diagnosis scheme for lithium-ion batteries is proposed. By applying both the discrete Fréchet distance and local outlier factor to the voltage and temperature data of the battery cell/module that measured in real time, the battery cell that will have thermal runaway is detected before thermal runaway happens. Compared with the widely used single parameter based diagnosis approach, the proposed one considerably improve the reliability of the fault diagnosis and reduce the false diagnosis rate. The effectiveness of the proposed method is validated with the operational data from electric vehicles with/without thermal runaway in daily use.","Discrete Fréchet distance (DFD); fault diagnosis; lithium-ion battery (LIB); local outlier factor (LOF)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","DC systems, Energy conversion & Storage","","",""
"uuid:b26686ea-717d-4686-b2b1-0b233d369bfc","http://resolver.tudelft.nl/uuid:b26686ea-717d-4686-b2b1-0b233d369bfc","Collision-Aware Fast Simulation for Soft Robots by Optimization-Based Geometric Computing","Fang, G. (TU Delft Emerging Materials; The University of Manchester); Tian, Yingjun (The University of Manchester); Weightman, Andrew (The University of Manchester); Wang, C.C. (The University of Manchester)","","2022","Soft robots can safely interact with environments because of their mechanical compliance. Self-collision is also employed in the modern design of soft robots to enhance their performance during different tasks. However, developing an efficient and reliable simulator that can handle the collision response well, is still a challenging task in the research of soft robotics. This paper presents a collision-aware simulator based on geometric optimization, in which we develop a highly efficient and realistic collision checking / response model incorporating a hyperelastic material property. Both actuated deformation and collision response for soft robots are formulated as geometry-based objectives. The collision-free body of a soft robot can be obtained by minimizing the geometry-based objective function. Unlike the FEA-based physical simulation, the proposed pipeline performs a much lower computational cost. Moreover, adaptive remeshing is applied to achieve the improvement of the convergence when dealing with soft robots that have large volume variations. Experimental tests are conducted on different soft robots to verify the performance of our approach.","","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Emerging Materials","","",""
"uuid:617f7d1b-91b7-4fc7-bb7b-f0ac2352d028","http://resolver.tudelft.nl/uuid:617f7d1b-91b7-4fc7-bb7b-f0ac2352d028","Sandstone body character and river planform styles of the lower Eocene Willwood Formation, Bighorn Basin, Wyoming, USA","Wang, Y. (TU Delft Applied Geology); Baars, T.F. (TU Delft Applied Geology); Sahoo, H. (TU Delft Applied Geology); Storms, J.E.A. (TU Delft Applied Geology); Martinius, A.W. (TU Delft Applied Geology; Equinor ASA); Gingerich, Philip (University of Michigan); Abels, H.A. (TU Delft Applied Geology)","","2022","ABSTRACT The lower Eocene Willwood Formation of the Bighorn Basin, Wyoming, USA, is an alluvial succession with a sand content varying around 25 palaeoenvironments and palaeoclimates, as well as sedimentological and stratigraphic analysis. Channel dynamics were studied at a relatively low resolution throughout the basin over the geological time from late Palaeocene to early Eocene. Here, a high-resolution study is reported to complement previous research at the basin scale. Efforts are made to document the characteristics and river planform styles of most sandstone bodies encountered through ca 300 m of alluvial stratigraphy in a 10 km2 area of the Deer Creek part of the McCullough Peaks area situated in the basin axis of northern Bighorn Basin. Four channel facies associations are recognized and ascribed to four river planform styles: crevasse channel, trunk channel, braided-like channel and sinuous-like channel, with the latter two types dominant. Braided-like and sinuous-like channel sandstone bodies differ significantly in thicknesses, being on average 6.1 m versus 9.0 m, but they have similar palaeoflow–perpendicular widths of on average 231 m and palaeoflow directions of on average N 003°. Braided-like and sinuous-like river planform styles show no spatial dependency in the 10 km2 study area. Results of this study are in line with existing basin-scale depositional models that are composed of a single axial system fed by several transverse systems dominantly from the west. The feeding of these systems could be influenced by palaeoclimate changes possibly controlling their contribution over time, thereby impacting river planform styles. At the same time, changing water discharge hydrograph, sediment load, and overbank cohesiveness may have equally driven the observed river planform style changes within the basin without a major role of catchments.","Bighorn Basin; channel sandstone body; Willwood Formation; palaeogeography; river planform style","en","journal article","","","","","","","","","","","Applied Geology","","",""
"uuid:856a5681-2d68-4f42-9cc6-71c26a06b10e","http://resolver.tudelft.nl/uuid:856a5681-2d68-4f42-9cc6-71c26a06b10e","Prediction-Based Reachability Analysis for Collision Risk Assessment on Highways","Wang, X. (TU Delft Learning & Autonomous Control); Li, Z. (TU Delft Transport and Planning; Beijing Institute of Technology); Alonso-Mora, J. (TU Delft Learning & Autonomous Control); Wang, M. (TU Delft Transport and Planning; Technische Universität Dresden)","","2022","Real-time safety systems are crucial components of intelligent vehicles. This paper introduces a prediction-based collision risk assessment approach on highways. Given a point mass vehicle dynamics system, a stochastic forward reachable set considering two-dimensional motion with vehicle state probability distributions is firstly established. We then develop an acceleration prediction model, which provides multi-modal probabilistic acceleration distributions to propagate vehicle states. The collision probability is calculated by summing up the probabilities of the states where two vehicles spatially overlap. Simulation results show that the prediction model has superior performance in terms of vehicle motion position errors, and the proposed collision detection approach is agile and effective to identify the collision in cut-in crash events.","Road transportation; Intelligent vehicles; Simulation; Stochastic processes; Predictive models; Probability distribution; Risk management","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-01-19","","Transport and Planning","Learning & Autonomous Control","","",""
"uuid:853a5546-a7da-4e99-87e6-44496bb35251","http://resolver.tudelft.nl/uuid:853a5546-a7da-4e99-87e6-44496bb35251","Probabilistic Risk Metric for Highway Driving Leveraging Multi-Modal Trajectory Predictions","Wang, X. (TU Delft Transport and Planning); Alonso-Mora, J. (TU Delft Learning & Autonomous Control); Wang, M. (TU Delft Transport and Planning; Technische Universität Dresden)","","2022","Road traffic safety has attracted increasing research attention, in particular in the current transition from human-driven vehicles to autonomous vehicles. Surrogate measures of safety are widely used to assess traffic safety but they typically ignore motion uncertainties and are inflexible in dealing with two-dimensional motion. Meanwhile, learning-based lane-change and trajectory prediction models have shown potential to provide accurate prediction results. We therefore propose a prediction-based driving risk metric for two-dimensional motion on multi-lane highways, expressed by the maximum risk value over different time instants within a prediction horizon. At each time instant, the risk of the vehicle is estimated as the sum of weighted risks over each mode in a finite set of lane-change maneuver possibilities. Under each maneuver mode, the risk is calculated as the product of three factors: lane-change maneuver mode probability, collision probability and expected crash severity. The three factors are estimated leveraging two-stage multi-modal trajectory predictions for surrounding vehicles: first a lane-change intention prediction module is invoked to provide lane-change maneuver mode possibilities, and then the mode possibilities are used as partial input for a multi-modal trajectory prediction module. Working with the empirical trajectory dataset highD and simulated highway scenarios, the proposed two-stage model achieves superior performance compared to a state-of-the-art prediction model. The proposed risk metric is computationally efficient for real-time applications, and effective to identify potential crashes earlier thanks to the employed prediction model.","Accidents; Computational modeling; Lane-change intention prediction; Measurement; Predictive models; probabilistic collision calculation; risk assessment; Safety; Trajectory; trajectory prediction.; Uncertainty","en","journal article","","","","","","","","","","Transport and Planning","Transport and Planning","","",""
"uuid:aaac9208-ae4d-4d82-8bfb-c04be7b20505","http://resolver.tudelft.nl/uuid:aaac9208-ae4d-4d82-8bfb-c04be7b20505","A virtual experiment for measuring system resilience: a case of chemical process systems","Sun, H. (TU Delft Safety and Security Science; China University of Petroleum (East China)); Yang, M. (TU Delft Safety and Security Science; Universiti Teknologi Malaysia); Wang, Haiqing (China University of Petroleum (East China))","","2022","Resilience is an emergent property of a system, which changes with various internal and external factors. Resilience is also a hidden property of a system that cannot be observed. Thus, experiments should be performed for a given system to measure its resilience. However, physical experiments are practically impossible. Inspired by the tensile test for the stress-strain curve in Material Science, this paper proposes a virtual experiment for measuring system resilience and applies it to a chemical process system. The physical parameters of system resilience of a process system are mapped to those of material resilience. A process system is viewed as a 'specimen' in this experiment. The system performance variation caused by disruptions is seen as the displacement of the specimen caused by the applied load. In absorption phase, the decrease speed of system performance is determined by the failure rate of components under disruptive condition. Response time, including fault diagnosis time and resource allocation time, is used to represent adaptation ability. Restoration ability depends on repair rate of components. For simplicity purpose, the proposed method is applied to resilience assessment of a release prevention barrier system used in the Chevron Richmond refinery crude unit and its associated upstream process.","resilience; process safety; chemical process system; hazardous operation","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:fdbb4fb8-2298-4a44-a326-f077f6860a32","http://resolver.tudelft.nl/uuid:fdbb4fb8-2298-4a44-a326-f077f6860a32","Microstructural Evolution and Behavior of Deuterium in a Ferritic ODS 12 Cr Steel Annealed at Different Temperatures","Marques Pereira, V. (TU Delft Team Kevin Rossi); Wang, S. (Dutch Institute for Fundamental Energy Research); Morgan, T. (Dutch Institute for Fundamental Energy Research); Schut, H. (TU Delft RST/Neutron and Positron Methods in Materials); Sietsma, J. (TU Delft Team Kevin Rossi)","","2022","In the present work, an ODS 12 Cr steel was characterized using Electron Microscopy techniques, in an as-received condition and after annealing treatments between 773 K and 1573 K. Results show a complex microstructure, with the presence of fine Y–Ti–O nanoparticles dispersed in the matrix. After annealing at 1573 K, the average diameter of Y–Ti–O nanoparticles increases from ~ 4 to ~ 7 nm and partial recrystallization occurs. The trapping behavior of deuterium in the steel in its as-received state and annealed at 1573 K was investigated. Samples were exposed to low-energy deuterium plasma and analyzed with thermal desorption spectroscopy, after waiting times of 1 day and 25 days. The samples measured 1 day after exposure released a higher total amount of deuterium than the ones measured after 25 days. The effect of waiting time is explained by the release of deuterium, at 300 K, from sites with low activation energy for detrapping, Ed. In the as-received condition, part of the deuterium detrapped at 300 K was re-trapped by high-Ed sites. For the samples in the annealed condition, the redistribution of deuterium from low-Ed to high-Ed sites was not observed, but the total amount of deuterium released was higher.","","en","journal article","","","","","","","","","","","RST/Neutron and Positron Methods in Materials","","",""
"uuid:0aaef8b0-390d-462e-b456-214ee6986b7d","http://resolver.tudelft.nl/uuid:0aaef8b0-390d-462e-b456-214ee6986b7d","Low-Temperature and Fatigue Characteristics of Degraded Crumb Rubber-Modified Bitumen before and after Aging","Wang, Sheng (Tongji University); Huang, Weidong (Tongji University); Lin, P. (TU Delft Pavement Engineering)","","2022","The high viscosity and poor storage stability of crumb rubber-modified asphalt (CRMA) can be partially addressed by the appropriate degree of degradation of the crumb rubber modifier. However, the low-Temperature and fatigue characteristics of degraded crumb rubber-modified bitumen (DCRMB) in different aging states are not well understood. In this study, two types of DCRMB-namely, terminal blend rubberized asphalt (TBRA) and terminal blend hybrid asphalt (TBHA)-were prepared with sulfur, styrene-butadiene-styrene (SBS) polymer, and crumb rubber (CR). All DCRMB binders were short-Term aged with a rolling thin film oven test (RTFOT) and long-Term aged with a pressure aging vessel (PAV). Afterward, a bending beam rheometer (BBR) test and a linear amplitude sweep (LAS) test were conducted to characterize the low-Temperature and fatigue properties of DCRMB binders at different aging degrees, respectively. Based on the rheological test results, several conclusions can be drawn. First, the BBR results indicated that the increase in CR content led to a slight increase in creep rate and a significant decrease in stiffness. Especially in PAV aging, the low-Temperature properties of DCRMB were much better than those of neat asphalt. Meanwhile, DCRMB demonstrated an advantage over neat asphalt in integrity and fatigue resistance before and after aging. Finally, based on correlation analysis, the LAS test is recommended for evaluating the fatigue properties of DCRMB before and after aging.","Bending beam rheometer (BBR) test; Correlation analysis; Degraded crumb rubber-modified bitumen (DCRMB); Linear amplitude sweep (LAS) test; Short-Term and long-Term aging","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Pavement Engineering","","",""
"uuid:e7636b15-974c-4268-9d8c-918f07b8105d","http://resolver.tudelft.nl/uuid:e7636b15-974c-4268-9d8c-918f07b8105d","Choice modelling in the age of machine learning - Discussion paper","van Cranenburgh, S. (TU Delft Transport and Logistics); Wang, Shenhao (Massachusetts Institute of Technology); Vij, Akshay (University of South Australia); Pereira, Francisco (Technical University of Denmark); Walker, Joan (University of California)","","2022","Since its inception, the choice modelling field has been dominated by theory-driven modelling approaches. Machine learning offers an alternative data-driven approach for modelling choice behaviour and is increasingly drawing interest in our field. Cross-pollination of machine learning models, techniques and practices could help overcome problems and limitations encountered in the current theory-driven modelling paradigm, such as subjective labour-intensive search processes for model selection, and the inability to work with text and image data. However, despite the potential benefits of using the advances of machine learning to improve choice modelling practices, the choice modelling field has been hesitant to embrace machine learning. This discussion paper aims to consolidate knowledge on the use of machine learning models, techniques and practices for choice modelling, and discuss their potential. Thereby, we hope not only to make the case that further integration of machine learning in choice modelling is beneficial, but also to further facilitate it. To this end, we clarify the similarities and differences between the two modelling paradigms; we review the use of machine learning for choice modelling; and we explore areas of opportunities for embracing machine learning models and techniques to improve our practices. To conclude this discussion paper, we put forward a set of research questions which must be addressed to better understand if and how machine learning can benefit choice modelling.","Choice modelling; Literature overview; Machine learning; Research agenda","en","journal article","","","","","","","","","","","Transport and Logistics","","",""
"uuid:67dcf697-9326-4cad-b39a-c3d28ff7e03c","http://resolver.tudelft.nl/uuid:67dcf697-9326-4cad-b39a-c3d28ff7e03c","A STAMP-based approach to quantitative resilience assessment of chemical process systems","Sun, H. (TU Delft Safety and Security Science; China University of Petroleum (East China)); Wang, Haiqing (China University of Petroleum (East China)); Yang, M. (TU Delft Safety and Security Science); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Universiteit Antwerpen; Katholieke Universiteit Leuven)","","2022","Chemical process systems (CPSs) involve complex dynamic processes. Besides, the emergent and uncertain hazards and disruptions cannot be identified entirely and prevented by conventional methods. In those situations, resilience for CPSs plays an essential role in absorbing, adapting to disruptions, and restoring from damages. Systemic modeling plays a vital role in assessing resilience. A system-based analysis model, system-theoretic accident model, and process (STAMP) can provide a robust framework. This paper develops a comprehensive methodology to systematically model and assess system resilience. The STAMP is employed to model and analyze the system safety of a process system. A new method of dynamic resilience assessment is then proposed to quantify the resilience of the system. The proposed method is applied to the diesel oil hydrogenation system. The results show that it quantifies the resilience of complex process systems considering human and organizational factors in a dynamic manner.","Chemical process systems; Resilience assessment; STAMP; Systemic","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:69f97604-bdda-466f-8482-91a0884fcfff","http://resolver.tudelft.nl/uuid:69f97604-bdda-466f-8482-91a0884fcfff","Chemoenzymatic intermolecular haloether synthesis","Chen, Shaohang (Wuhan University of Science and Technology); Zhang, Jiaan (Wuhan University of Science and Technology); Zeng, Zhigang (Wuhan University of Science and Technology); Dai, Zongjie (Chinese Academy of Sciences); Wang, Qinhong (Chinese Academy of Sciences); Wever, Ron (Universiteit van Amsterdam); Hollmann, F. (TU Delft BT/Biocatalysis); Zhang, W. (TU Delft BT/Biocatalysis; Chinese Academy of Sciences)","","2022","A chemoenzymatic method for the synthesis of haloethers is presented. A combination of enzymatic hypohalite synthesis with spontaneous oxidation of alkenes and nucleophilic attack by various alcohols enabled the synthesis of a wide range of haloethers. The reaction system has been characterised and current imitations have been worked out. In the present, aqueous reaction system, hydroxyhalide formation represents the main undesired side reaction. Nevertheless, semi-preparative scale synthesis of a range of haloethers is demonstrated.","Chemoenzymatic synthesis; Ether synthesis; Haloetherification; Vanadium chloroperoxidase","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:b6790c67-339e-407c-8597-2414f27cbf0f","http://resolver.tudelft.nl/uuid:b6790c67-339e-407c-8597-2414f27cbf0f","Mechanisms Controlling the Distribution of Net Water Transport in Estuarine Networks","Wang, Jinyang (Universiteit Utrecht); Dijkstra, Y.M. (TU Delft Mathematical Physics); de Swart, Huib E. (Universiteit Utrecht)","","2022","Net water transport (NWT) in estuaries is important for, for example, salt intrusion and sediment dynamics. While NWT is only determined by river runoff in single channels, in estuarine networks, it results from a complex interplay between tides and residual flows. This study aims to disentangle the various contributions of these physical drivers to NWT in estuarine networks and investigate the sensitivities of NWT to variable forcing conditions, interventions, and sea level rise (SLR). To this end, a processes-based perturbative network model is developed, which accounts for the vertical flow structure to resolve density-driven flow driven by a vertically uniform along-channel salinity gradient. Other identified drivers are river discharge and three tidal rectification processes: Stokes transport and its return flow, momentum advection, and velocity-depth asymmetry. The model is applied to the Yangtze Estuary. NWT due to tidal rectifications and density-driven flow can be comparable to river discharge. Specifically in the North Branch, the direction of NWT may differ from the direction of river discharge. Varying river discharge mainly affects NWT as tide-river interaction is weak and density-driven flow is shown to be insensitive to salt intrusion. Conversely, variations in tidal amplitude strongly affect NWT related to tidal rectification and density-driven flow. The deepening (narrowing) of one channel (Deep Waterway Project), affected the NWT mostly through the density-driven flow (advection). Furthermore, NWT distribution in the Yangtze is insensitive to SLR up to 2 m because the effects of SLR on transport due to different drivers compensate each other.","net water transport; river-tide interaction; Yangtze Estuary","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:32f3c456-d017-47bb-afaf-d57fe15a8123","http://resolver.tudelft.nl/uuid:32f3c456-d017-47bb-afaf-d57fe15a8123","Experimental study and discrete element analysis on lateral resistance of windblown sand railway","Zhang, Zhihai (Beijing Jiaotong University); Xiao, Hong (Beijing Jiaotong University); Wang, Y. (Beijing Jiaotong University); Fang, Jia (Beijing Jiaotong University); Nadakatti, M. M. (KLSGIT); Wang, Haoyu (TU Delft Mechanics and Physics of Structures)","","2022","The lateral resistance of ballast bed is an important parameter to prevent track expansion and maintain track stability. The invasion of sand particles can cause the change of lateral resistance of ballast bed and affect the stability of track structure, but little attention has been paid to the change characteristics of nonlinear lateral resistance of sandy ballast bed. In this paper, the field tests on the lateral resistance of windblown sand ballast bed were carried out to establish a multiscale three-dimensional discrete element model of sleeper-ballast bed. A systematic analysis on the evolution of lateral resistance, resistance to lateral deformation, micro-contact characteristics and lateral stability of ballast bed is performed. The results show that sand intrusion can increase the lateral resistance of ballast bed, which is approximately 40 % higher than that of clean ballast bed. In nonlinear strengthening stage and yield stage, the enhancement effect of sand particles on the lateral resistance of ballast bed is relatively weaker in comparison with the linear growth stage. With the increase in sand intrusion depth, the lateral resistance and resistance work of ballast bed both gradually go up, and the contribution of ballast shoulder to lateral resistance tends to play a leading role. Sand intrusion can increase the lateral stiffness of ballast bed and reduce the elasticity of track structure. Therefore, the maintenance operation should be carried out in time for the section with severe sandstorm.","Contact force; Cyclic loading; Discrete element method; Lateral resistance; Lateral resistance work; Windblown sand ballast bed","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Mechanics and Physics of Structures","","",""
"uuid:d3b1b7aa-f70f-4d03-ae26-c34258cc0e65","http://resolver.tudelft.nl/uuid:d3b1b7aa-f70f-4d03-ae26-c34258cc0e65","Surface Redox Pseudocapacitance of Partially Oxidized Titanium Carbide MXene in Water-in-Salt Electrolyte","Wang, Xuehang (TU Delft RST/Storage of Electrochemical Energy; Drexel University); Bak, Seong Min (Brookhaven National Laboratory); Han, Meikang (Drexel University); Shuck, Christopher E. (Drexel University); Mchugh, Conlan (Drexel University); Li, Ke (Drexel University); Li, Jianmin (Drexel University); Tang, J. (Drexel University); Gogotsi, Yury (Drexel University)","","2022","Achieving pseudocapacitive intercalation in MXenes with neutral aqueous electrolytes and driving reversible redox reactions is scientifically appealing and practically useful. Here, we report that the partial oxidation of MXene intensifies pseudocapacitive Li+ intercalation into Ti3C2Tx MXene from neutral water-in-salt electrolytes. An in situ X-ray absorption near-edge structure analysis shows that the Ti oxidation state changes during the Li+ intercalation, indicating the presence of a surface redox reaction. The Ti oxidation/reduction is further confirmed by an in situ extended X-ray absorption fine structure analysis, which shows a reversible contraction/expansion of the Ti-C interatomic distance. The intensified Li+ pseudocapacitive intercalation can be explained by the higher oxidation state of Ti at the open circuit potential. This work demonstrates the possibility of tuning the pseudocapacitive intercalation by adjusting the initial oxidation state of the transition metal on the MXene and offers a facile way to enhance the pseudocapacitance of various MXenes.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","RST/Storage of Electrochemical Energy","","",""
"uuid:f6d09e83-b104-480d-81c9-bae95821d498","http://resolver.tudelft.nl/uuid:f6d09e83-b104-480d-81c9-bae95821d498","Joint energy consumption optimization method for wing-diesel engine-powered hybrid ships towards a more energy-efficient shipping","Wang, Kai (Dalian Maritime University); Xue, Yu (Dalian Maritime University); Xu, Hao (Dalian Maritime University); Huang, Lianzhong (Dalian Maritime University); Ma, Ranqi (Dalian Maritime University); Zhang, Peng (Dalian Maritime University); Jiang, X. (TU Delft Transport Engineering and Logistics); Yuan, Yupeng (University of Cambridge; MOST); Negenborn, R.R. (TU Delft Transport Engineering and Logistics); Sun, Peiting (Dalian Maritime University)","","2022","Wing-diesel engine-powered hybrid ships can effectively reduce fuel consumption and CO2 emissions by using wind energy as the auxiliary driving power. The energy optimization management of the hybrid system can further improve the ship's energy efficiency. To achieve this purpose, it is significant to establish an effective energy consumption model for the energy optimization management of the hybrid system. Therefore, an energy consumption model is established based on the energy conversion analysis of the hybrid power system in this paper. This model can effectively describe the energy consumption of the hybrid ship under different navigational environmental conditions. Then, a joint optimization method of the wing attack angle and of the sailing speed for the hybrid ship is proposed by adopting a swarm intelligence optimization algorithm, in order to reduce energy consumption and CO2 emissions of the hybrid ship under different navigational environmental conditions. Finally, the energy consumption optimization potentials by adopting the hybrid power system and the proposed joint optimization method are analyzed. The results show that the energy consumption and CO2 emissions along a typical route can be reduced by about 4.5%. This study provides an important basis for future practical operations of wing-diesel engine-powered hybrid ships.","Carbon neutrality; Energy consumption optimization; Hybrid ship; Low carbon shipping; Wind energy","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-07-29","","","Transport Engineering and Logistics","","",""
"uuid:05393515-af12-4189-a6f7-c59e3f13600f","http://resolver.tudelft.nl/uuid:05393515-af12-4189-a6f7-c59e3f13600f","Efficient semiparametric estimation of time-censored intensity-reduction models for repairable systems","Wang, Jinyang (National University of Singapore); Chen, P. (TU Delft Statistics); Ye, Zhisheng (National University of Singapore)","","2022","The rate reduction models have been widely used to model the recurrent failure data for their capabilities in quantifying the repair effects. Despite the widespread popularity, there have been limited studies on statistical inference of most failure rate reduction models. In view of this fact, this study proposes a semiparametric estimation framework for a general class of such models, called extended geometric failure rate reduction (EGFRR) models. Covariates are considered in our analysis and their effects are modeled as a log-linear factor on the baseline failure rate. Unlike the existing inference methods for the EGFRR models that assume the failure data are censored at a fixed number of failures, our study considers covariates and time-censoring, which are more common in practice. The semiparametric maximum likelihood (ML) estimators are obtained by carefully constructing the likelihood function. Asymptotic properties including consistency and weak convergence of the ML estimators are established by using the properties of the martingale process. In addition, we show that the semiparametric estimators are asymptotically efficient. A real example from the automobile industry illustrates the usefulness of the proposed framework and extensive simulations show its outstanding performance when comparing with the existing methods.","imperfect repair; martingale; recurrent events; repairable systems; semiparametric efficiency","en","journal article","","","","","","","","","","","Statistics","","",""
"uuid:b112dd78-7193-4825-8505-6fa01b270235","http://resolver.tudelft.nl/uuid:b112dd78-7193-4825-8505-6fa01b270235","River, tide and morphology interaction in a macro-tidal estuary with active morphological evolutions","Xie, Dongfeng (Zhejiang Institute of Hydraulics and Estuary); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); Huang, Junbao (Zhejiang Institute of Hydraulics and Estuary); Zeng, Jian (Zhejiang Institute of Hydraulics and Estuary)","","2022","Understanding tidal dynamics in estuaries is essential for tidal predictions and assessments of sediment transport and associated morphological changes. Most studies on river-tide interaction ignored the influences of morphological evolutions under natural conditions such as the seasonal and interannual variations of river discharge. This study analyzes the multiple-timescale tidal dynamics in the Qiantang Estuary, a macro-tidal estuary in China with an extremely active morphological evolution. A large dataset including water levels at representative stations, river discharges and bathymetries since 1980 has been collected. The results of the analysis show that within a spring-neap cycle, the tidal amplification in the upper estuary is stronger during spring tide than during neap tide. This unexpected behavior is due to the high sediment concentration and the unique longitudinal profile of the estuary. On the seasonal and interannual timescales, the low water levels in the upper estuary depend on the local bathymetrical conditions. Tidal ranges in the upper estuary are larger in the high flow season and years, than in the low flow season and years, due to the erosion at high flow, in contrast to estuaries with less active morphological changes. During low flow season and years, the bed is gradually recovered, the low waters are elevated, and the tidal ranges decrease accordingly. A good relationship exists between the tidal ranges and the depth of the upper estuary. In the lower estuary, the flood dominance increases continuously due to embankment. In the upper estuary, the flood dominance is increased during the high flow periods, explaining the fast sediment input and bed recovery in the post high flow periods. A conceptual model of river-tide-morphology interaction of the estuary is proposed, which is also applicable for other shallow systems.","Morphological evolution; Qiantang Estuary; River discharge; Tidal amplification; Tidal dynamics","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Coastal Engineering","","",""
"uuid:67bfc3b1-7b01-4ce7-92bf-6021b5ca6cdd","http://resolver.tudelft.nl/uuid:67bfc3b1-7b01-4ce7-92bf-6021b5ca6cdd","Effects of microporous layer on electrolyte flooding in gas diffusion electrodes and selectivity of CO2 electrolysis to CO","Wu, Yuming (University of Queensland); Garg, Sahil (Technical University of Denmark); Li, Mengran (TU Delft ChemE/Materials for Energy Conversion and Storage); Idros, Mohamed Nazmi (University of Queensland); Li, Zhiheng (University of Queensland); Lin, Rijia (University of Queensland); Chen, Jian (University of Queensland); Wang, Guoxiong (University of Queensland); Rufford, Thomas E. (University of Queensland)","","2022","Understanding the relationship between gas diffusion electrode (GDE) structures and the performance of electrochemical CO2 reduction reaction (CO2RR) is crucial to developing industrial-scale technologies to convert CO2 to valuable products. We studied how the microporous layer (MPL) on GDE's coated with silver nanoparticle catalysts affects the electrochemical CO2 conversion to CO in a flow cell electrolyser. We demonstrate a convenient method to measure the rate of catholyte seepage through a GDE during CO2RR experiments and used this method to show how the MPL thickness affects flooding of the GDE. We found the GDE with the thickest MPL (39BB) had the best selectivity for CO and stability at current densities above 100 mA cm−2 as the thick MPL minimized flooding. However, at low current densities the 39BB electrode achieved a lower CO selectivity than the GDE with thinner MPL. These results suggest opportunities to improve CO2 electrolyser performances at high current by optimisation of the MPL structure and wettability.","Electrochemical CO reduction; Electrolyte flooding; Gas diffusion electrode; Microporous layer; Thickness","en","journal article","","","","","","","","","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:cab23bfe-ffe5-439a-b5c9-dea05ade614f","http://resolver.tudelft.nl/uuid:cab23bfe-ffe5-439a-b5c9-dea05ade614f","Multifunctional pressure/temperature/bending sensor made of carbon fibre-multiwall carbon nanotubes for artificial electronic application","Wang, H. (TU Delft Aerospace Manufacturing Technologies; Nanjing University of Aeronautics and Astronautics); Tao, Jie (Nanjing University of Aeronautics and Astronautics); Jin, Kai (Ocean University of China); Wang, Xiaoyue (Nanjing University of Aeronautics and Astronautics); Dong, Ying (Nanjing University of Aeronautics and Astronautics)","","2022","A flexible sensor with excellent pressure, temperature, and bending sensitivity is fabricated based on the conductive skeleton material with hierarchical porous structure. The conductive skeleton material is composed of carbon fibres (CFs) and multiwalled carbon nanotubes (MWCNTs), in which lay perpendicular to each other CFs are used as conductive frames, while MWCNTs are served as bridges to connect the CFs and increase the conductive network formation. Owing to the unique structure and the conductive materials, the as-prepared sensor exhibits a high-pressure sensing performance of 42.7 kPa (0–1 kPa), fast response, relaxation times of<100 ms, wide working range of 0–60 kPa, and high stability over more than 6000 cycles. Furthermore, the fabricated sensor presents a high thermal sensitivity of 2.46 °C−1 between 30 and 40 °C, excellent bending sensitivity of 95.5 % rad−1 in the working range of 0–180°, and great flexibility (over 1000 cycles), demonstrating its potential applications in multifunctional wearable electronics.","Carbon fibres; Carbon nanotube; Freeze casting; Hierarchical porous structure; Multifunctional composites","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Aerospace Manufacturing Technologies","","",""
"uuid:faaf2d5a-635e-47fc-a993-ec99b6000ea0","http://resolver.tudelft.nl/uuid:faaf2d5a-635e-47fc-a993-ec99b6000ea0","Mechanical behaviour and energy evolution of polyurethane-mixed ballast under revised bonding constitutive model","Xiao, Hong (Beijing Jiaotong University); Ling, Xing (Beijing Jiaotong University); Wang, Meng (China Academy of Railway Sciences); Fang, Shu Wei (Beijing Metro Operation Co., Beijing); Wang, Haoyu (TU Delft Mechanics and Physics of Structures)","","2022","The bonding contact presents complex modes in polyurethane-mixed ballast. The commonly used parallel bond model is revised and four different contact models are developed including Ballast-Ballast Contact Bonding, Ballast-Ballast Noncontact Bonding, Ballast-Sleeper Contact Bonding, and Ballast-Sleeper Noncontact Bonding. The mechanical behaviour and energy evolution of polyurethane-mixed ballast with various amounts of glue are studied from the macro and mesoscopic properties. Results show that the elastic strain energy has always been the main form in polyurethane-mixed bed, followed by viscous strain energy, frictional energy, and damping energy. Compared with the common ballast bed, there are more contacts in polyurethane-mixed ballast bed and, when more glue is used, the amount of contacts is further increased while the maximum contact force is reduced. After bonding, the amount of contacts is significantly increased and all forms of energy become more evenly distributed at different surfaces of the sleeper. The kinetic energy of polyurethane-mixed ballast fluctuates with smaller amplitude and convergences more quickly under cyclic loading, which is reflected in the macroscopic aspect that the settlement of polyurethane-mixed ballast bed is relatively small and can be fast completed.","Constitutive model; Energy evolution; Mechanical behaviour; Polyurethane-mixed ballast","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Mechanics and Physics of Structures","","",""
"uuid:88c444bd-2bfe-42c5-a53e-155154d6ddb8","http://resolver.tudelft.nl/uuid:88c444bd-2bfe-42c5-a53e-155154d6ddb8","Zeolite membranes – The importance of support analysis","Kapteijn, F. (TU Delft ChemE/Catalysis Engineering); Wang, Xuerui (Nanjing Tech University)","","2022","Zeolite membranes are highly attractive in energy efficient, selective separation technologies. Their high selectivity originates from selective adsorption, diffusion and even molecular sieving. High flux zeolite membranes (> 1 mol s−1m−2) with a sub-micrometer thickness are mechanically stabilized by a porous, often multilayer, support. Transport mechanisms in zeolite layer and support, however, are counteracting regarding selectivity, and a support may also act as a flux resistance. Several examples are analyzed quantifying the impact of the support on the observed performance, showing the effect of layer thickness, orientation of the asymmetric membrane and operational conditions, resulting in recommendations for the configuration of zeolite membrane modules.","","en","review","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:5f2ebe0b-dc5e-4067-b496-31db3090c2a2","http://resolver.tudelft.nl/uuid:5f2ebe0b-dc5e-4067-b496-31db3090c2a2","Ground vibration induced by high speed trains on an embankment with pile-board foundation: Modelling and validation with in situ tests","Wang, L. (TU Delft Railway Engineering; Southwest Jiaotong University); Wang, Ping (Southwest Jiaotong University); Wei, Kai (Southwest Jiaotong University); Dollevoet, R.P.B.J. (TU Delft Railway Engineering); Li, Z. (TU Delft Railway Engineering)","","2022","To investigate the train-induced ground vibration, an explicit time-domain, three dimensional (3D) finite element (FE) model is developed. The train, track, embankment, pile-board structure and nearby ground soils are all fully coupled in this model. The complex geometries involving the track components and pile-board structure are all modelled in detail, which makes the simulation of wave propagation more realistic from the train to the ground. The model is validated with in situ tests data collected in the Beijing-Shanghai high speed railway line. Good agreements have been achieved between the numerical results and experimental results both in time domain and frequency domain. The proposed model is thus capable of reproducing the dynamic ground response induced by a typical high speed train. Soil responses induced by different number of vehicles are compared. With more vehicles, the spectral peaks of soil responses are more prominent at the integral multiples of the vehicle passing frequency. Too few vehicles will not bring about such phenomenon, thus sufficient number of vehicles should be included in a train to properly model train-induced ground vibration. With the proposed model, the influence of the pile-board foundation on the ground vibration is investigated. It is found that the pile-board foundation can significantly attenuate the low frequency ground vibration. The attenuation of the ground vibration as a function of distance from the track is simulated and the influential factors to the local vibration amplification are investigated. It is found that soil Young's modulus and soil impedance contrast are the two main factors influential to the local vibration amplification. The softer the natural soil, the larger the amplification. The larger soil impedance contrast makes the amplification more obvious. The soil stratification and geometric discontinuity at ground surface are not the main cause of the local vibration amplification in this work.","Finite element model; Ground vibration; High speed railway; Local vibration amplification; Pile-board structure; Soft soil","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-07-27","","","Railway Engineering","","",""
"uuid:b20e5945-bf01-447e-b771-2af092301668","http://resolver.tudelft.nl/uuid:b20e5945-bf01-447e-b771-2af092301668","Subwavelength spinning of particles in vector cosine-Gaussian field with radial polarization","Zhao, Rui (Shandong University of Technology); Jiang, M. (TU Delft ImPhys/Optics); Zhang, Shuoshuo (Shenzhen University); Man, Zhongsheng (Shandong University of Technology; Shandong Normal University); Wang, Benyi (Shandong University of Technology); Ge, Xiaolu (Shandong University of Technology); Zhang, Wenfei (Shandong University of Technology); Zhang, Yuquan (Shenzhen University); Fu, Shenggui (Shandong University of Technology)","","2022","A new type of radially polarized (RP) cosine-Gaussian (CG) field is proposed. Through the analytical model, it is found that such RP CG beam exhibits completely different focusing properties from the reported RP plane waves. More importantly, a stable three-dimensional trap of Rayleigh particle accompanied by a subwavelength spin motion can be easily achieved using this RP CG beam.","Cosine-Gaussian field; Diffractive optics; Optical trapping; Radial polarization","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","ImPhys/Optics","","",""
"uuid:7a9849c6-522c-4922-a0ba-f5ca7214f69c","http://resolver.tudelft.nl/uuid:7a9849c6-522c-4922-a0ba-f5ca7214f69c","Supplementary control based on current source coupling for improving dynamic characteristics of active distribution network","Hou, Jue (Huazhong University of Science and Technology); Liu, Zhou (Aalborg University); Wang, Shaorong (Huazhong University of Science and Technology); Chen, Zhe (Aalborg University); Xie, Wei (The State Grid Shanghai Municipal Electric Power Company); Fang, Cheng (The State Grid Shanghai Municipal Electric Power Company); Wei, Xinchi (The State Grid Shanghai Municipal Electric Power Company); Popov, M. (TU Delft Intelligent Electrical Power Grids)","","2022","Supplementary control (SC) technology is widely leveraged by power supply companies in active distribution networks (ADNs) to improve their stability and dynamic characteristics. Yet, the existed SCs are generally implemented from inside the converter controllers of distributed generators (DGs) or active loads, so there is a need to redesign the internal physical structure of the existing controller, resulting in the increasing work amount of assembling and workability. This paper studies the specific R & D process of a novel external coupling type SC (ECSC), which is based upon current source injection (CSI-ECSC) for improving the dynamic characteristics of ADN. The SC current signals are coupled to the current sampling loop from outside the converter controller. And the employment of the existing current sample makes it unnecessary to redesign the internal physical structure of the existing controller. As a result, the SC assembling is simplified and its workability is improved. In this paper, a detailed exemplary ADN with direct-drive permanent magnet synchronous generator (PMSG) is firstly set up in math for full eigenvalue analysis. Then, the CSI-ECSC is designed with its control loop, interface circuit, and parameter setting. Furthermore, by using PSCAD/EMTDC, groups of case studies are conducted in ADNs where photovoltaics (PVs) and energy storage (ES) are included. Finally, the real-time hardware-in-the-loop (HIL) testing validates the functionality of the realized CSI-ECSC in RTDS.","Active distribution network; Converter controller; Eigenvalue analysis; Hardware in the loop; RTDS; Supplementary control","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-03-03","","","Intelligent Electrical Power Grids","","",""
"uuid:1cfb6b33-55e4-4f70-8b6e-28fa004904a5","http://resolver.tudelft.nl/uuid:1cfb6b33-55e4-4f70-8b6e-28fa004904a5","Revealing the influence of Mo addition on interphase precipitation in Ti-bearing low carbon steels","Dong, Haokai (Tsinghua University; South China University of Technology); Chen, Hao (Tsinghua University); Riyahi khorasgani, Ahmadreza (Center for Interface-Dominated High Performance Materials); Zhang, Boning (Tsinghua University); Zhang, Yongjie (Tohoku University); Wang, Zhenqiang (Harbin Engineering University); Zhou, Xiaosheng (Tsinghua University); Wang, Wei (Baosteel Research Institute); van der Zwaag, S. (TU Delft Novel Aerospace Materials; Tsinghua University)","","2022","Mo is widely used as an effective microalloying element to improve mechanical performance of interphase precipitation steels, but the precise role of Mo in interphase precipitation behavior is not fully understood. In this contribution, interphase precipitation behavior in a series of Ti-Mo-bearing low carbon steels is systematically studied, and the role of Mo in interphase precipitates and its coarsening behavior is revisited. It is found that (Ti, Mo)C precipitates instead of TiC are formed in the Mo-containing alloys, and the average site fraction of Mo in (Ti, Mo)C is almost independent of the bulk Mo content. Moreover, the number density of interphase precipitates can be substantially enhanced by a minor addition of Mo, albeit it does not further rise with increasing the bulk Mo content. This is because the Mo fraction in (Ti, Mo)C rather than the bulk Mo content governs the driving force for precipitation nucleation and the interfacial energy of the (Ti, Mo)C/α and (Ti, Mo)C/γ interfaces. In addition to the reduced interfacial energy, decrease of Ti trans-interface diffusivity has been identified as another key reason for the enhanced carbide coarsening resistance in Mo-containing alloys.","(Ti, Mo)C; Carbide nucleation; Coarsening resistance; Interfacial energy; Interphase precipitation; Trans-interface diffusivity","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-05-16","","","Novel Aerospace Materials","","",""
"uuid:01ab6a89-b472-4a4f-b2f6-49e3013171a1","http://resolver.tudelft.nl/uuid:01ab6a89-b472-4a4f-b2f6-49e3013171a1","Development of intertidal flats in the Dutch Wadden Sea in response to a rising sea level: Spatial differentiation and sensitivity to the rate of sea level rise","Huismans, Y. (TU Delft Coastal Engineering; Deltares); van der Spek, A.J.F. (Deltares; Universiteit Utrecht); Lodder, Q.J. (TU Delft Coastal Engineering; Rijkswaterstaat); Zijlstra, Robert (Rijkswaterstaat); Elias, Edwin (Deltares); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2022","The Wadden Sea is a unique intertidal wetland area, forming an important hub for migratory water birds. A feared effect of accelerated sea-level rise (SLR) is the gradual loss or even disappearance of the ecologically valuable intertidal flats. To date, the effect of SLR on the time-evolution of the intertidal areas in the Dutch Wadden Sea has not been studied. To explore the sensitivity of the intertidal flats to SLR and the spatial differentiation of the response, simulations are carried out with the reduced-complexity model ASMITA for four sea level rise scenarios: one with a stable rate of 2 mm/yr (current rate), and three with accelerated sea level rise rates to respectively 4, 6 and 8 mm/yr. In addition, a scenario with a linearly increasing rate to 17 mm/yr in 2100 has been added to get an impression of what may happen under more extreme SLR-rates. The results show that the intertidal flats in the larger basins are most vulnerable to drowning. Due to differences in tidal flat geometry, the intertidal flats in the smaller basins mainly reduce in average height, while the intertidal flats in the larger basins mainly reduce in surface area. Within the basins, largest losses are expected to occur just off the land reclamation works and along the western part of each tidal watershed. The intertidal flats are sensitive to the rate of SLR. With doubling the rate of SLR, losses nearly double as well. Complete drowning is not predicted for any of the considered scenarios, but for the larger basins volume losses of nearly 50% by 2100 are predicted for the highest considered scenario. This will transform these basins into more lagoon-like basins, which is expected to have major consequences for the ecology.","ASMITA modelling; Intertidal flats; Sea-level rise; Wadden sea","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Coastal Engineering","","",""
"uuid:4e7c06f2-ddd5-4061-8fea-a0ef090d43c3","http://resolver.tudelft.nl/uuid:4e7c06f2-ddd5-4061-8fea-a0ef090d43c3","A single-layer approach for joint optimization of traffic signals and cooperative vehicle trajectories at isolated intersections","Liu, M. (TU Delft Transport and Planning); Zhao, J. (TU Delft Transport and Planning; University of Shanghai for Science and Technology); Hoogendoorn, S.P. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning)","","2022","A joint control approach that simultaneously optimizes traffic signals and trajectories of cooperative (automated) vehicle platooning at urban intersections is presented in this paper. In the proposed approach, the signal phase lengths and the accelerations of the controlled platoons are optimized to maximize comfort and minimize travel delay within the signal cycle, subject to motion constraints on speeds, accelerations and safe following gaps. The red phases are initially considered as logic constraints, and then recast as several linear constraints to enable efficient solutions. The proposed approach is solved by mixed integer linear programming (MILP) techniques after linearization of the objective function. The generated outputs of the MILP problem are the optimal signal timings and the optimal accelerations of all vehicles. This joint control approach is flexible in incorporating multiple platoons and traffic movements under different traffic demand levels and it does not require prespecified terminal conditions on position and speed at the signal cycle tail. The performance of the proposed control approach is verified by simulation at a standard four-arm intersection under the balanced and unbalanced vehicle arrival rates from different arms, taking the released traffic movement numbers, turning proportions, signal cycle lengths and the controlled vehicle numbers into account. The simulation results demonstrate the platoon performance of the joint controller (such as split, merge, acceleration and deceleration maneuvers) under the optimal signals. Based on the simulation results, the optimal patterns of trajectories and signals are explored, which provide insights into the optimal traffic control actions at intersections in a cooperative vehicle environment. Furthermore, the computational performance of the proposed control approach is analyzed, and the benefits of the proposed approach on the average travel delay, throughput, fuel consumption, and emission are proved by comparing with the two-layer approaches using the car following model, the signal optimization models, and the state-of-the-art approach.","Cooperative vehicles; Signal optimization; Trajectory planning; Urban intersections","en","journal article","","","","","","","","","","Transport and Planning","Transport and Planning","","",""
"uuid:f287c369-1e1a-4022-bf91-0a6c4c492757","http://resolver.tudelft.nl/uuid:f287c369-1e1a-4022-bf91-0a6c4c492757","Investigation of the hydration properties of cement with EDTA by alternative current impedance spectroscopy","Chi, Lin (University of Shanghai for Science and Technology; Harbin Institute of Technology); Li, Wenda (Harbin Institute of Technology); Li, Z. (TU Delft Materials and Environment); Wang, Zheng (Harbin Institute of Technology); Lu, Shuang (Harbin Institute of Technology); Liu, Qi (Harbin Institute of Technology)","","2022","Alternative current impedance spectroscopy (ACIS) is a promising non-destructive testing method to monitor long-term change and assess the durability of concrete. This study investigates the influences of Ethylene Diamine Tetraacetic Acid (EDTA) on the hydration of hardening cement by ACIS. It is found that EDTA retards the early-age hydration of cement but can facilitate the later age reaction. Pastes with EDTA show comparable or higher compressive strength than Control at 28 d, especially when the dosage is higher than 0.4%. Microstructural characterization results reveal the working mechanism of EDTA originating from its complexing effect on free ions. The resistivity evolution of the pastes detected by ACIS can well reflect the effects of EDTA on the cement hydration in different ages. Proportional relations are identified between the resistivity and other hydration parameters, such as reaction degree, chemical shrinkage, compressive strength. The results of this study indicate a wider prospect of ACIS in monitoring the microstructure evolution and macro-properties of cementitious materials.","Cement hydration; EDTA; Impedance; Microstructure; Non-destructive testing","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:65c25631-08bf-4e7a-b0b6-d74f8daf6d25","http://resolver.tudelft.nl/uuid:65c25631-08bf-4e7a-b0b6-d74f8daf6d25","Selectivity of vacuum ammonia stripping using porous gas-permeable and dense pervaporation membranes under various hydraulic conditions and feed water compositions","van Linden, N. (TU Delft Sanitary Engineering); Wang, Yundan (Student TU Delft); Sudhölter, Ernst J. R. (TU Delft ChemE/Advanced Soft Matter); Spanjers, H. (TU Delft Sanitary Engineering); van Lier, J.B. (TU Delft Sanitary Engineering)","","2022","Recovery of ammonia (NH3) from residual waters offers various reuse opportunities, such as the production of fertilisers and the generation of electricity and heat. However, simultaneous evaporation of water (H2O) during NH3 stripping under vacuum results in diluted recovered NH3 gas with high H2O contents. Whereas porous gas-permeable membranes are already used for vacuum NH3 stripping, the use of non-porous silica-based pervaporation (PV) membranes showed promising results in recent literature, with respect to more selective transfer of NH3 compared to H2O. In this study, we assessed the selectivity of NH3 over H2O transfer (SNH3/H2O) for different types of membranes, under various hydraulic conditions and feed water compositions. The three following membranes were tested: a porous gas-permeable polytetrafluoroethylene (PTFE) membrane, a hydrophilic (Hybrid Silica PV) membrane and a hydrophobic polydimethylsiloxane PV (PDMS PV) membrane. For the PTFE and the Hybrid Silica PV membrane, SNH3/H2O ranged between 0.1 and 0.4, indicating that the transfer of NH3 was consistently less preferred compared to the transfer of H2O. The preference for H2O over NH3 transfer through the membranes at various hydraulic conditions and feed water compositions can be assigned to the similarity in polarity and kinetic diameter of NH3 and H2O and the low relative concentration of NH3 in the used feed waters (approximately 0.1–1.0 wt%). The PDMS PV membrane showed negligible NH3 transfer and deteriorated rapidly during the NH3 stripping experiments. The SNH3/H2O of both gas-permeable and PV membranes was higher for unsteady than for steady hydraulic conditions. Furthermore, the SNH3/H2O of the both PTFE and the Hybrid Silica decreased when the ionic strength of the feed water increased from 0.0 to 0.8 mol∙L−1 and when the NH3 feed water concentration increased from 1 to 10 g∙L−1. According to the results, the used PV membranes did not show selectivity of NH3 over H2O transfer. In fact, the used PV membranes consistently had a lower SNH3/H2O than the PTFE membrane. Hence, the dense silica-based PV membranes did not allow for the recovery of gaseous NH3 from water, with lower H2O content in the recovered gas, compared to porous PTFE membranes.","Ammonia; Mass transfer coefficient; Pervaporation; Selectivity; Stripping; Water vapour","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:a11611a0-11e8-454f-ac2a-73d15d6f23a4","http://resolver.tudelft.nl/uuid:a11611a0-11e8-454f-ac2a-73d15d6f23a4","Ship docking and undocking control with adaptive-mutation beetle swarm prediction algorithm","Wang, Le (Wuhan University of Technology); Li, Shijie (Wuhan University of Technology); Liu, Jialun (Wuhan University of Technology; National Engineering Research Center for Water Transport Safety (WTSC)); Wu, Qing (Wuhan University of Technology); Negenborn, R.R. (TU Delft Transport Engineering and Logistics; Wuhan University of Technology)","","2022","Autonomous docking and undocking control is an important part of intelligent ship motion control. In this study, the adaptive-mutation beetle swarm prediction (AMBS-P) algorithm is used to propose a control approach for autonomous docking and undocking. Firstly, this paper introduces the principle of the AMBS-P algorithm, then the convergence is proved. Secondly, the “Tito-Neri” model ship is introduced as a case study, and the thrust allocation process is described. Finally, the effect of docking and undocking is verified in multiple scenarios starting from different angles. In the verification, first of all, when designing the docking and undocking controllers, the correctness of the algorithm and the practicality of the control are verified by whether there is ship drag or not. Secondly, by analyzing the parameters of the algorithm, the optimal parameters of it are determined and verified in the real environment. Thirdly, compared with typical proportion–integral–derivative (PID) algorithm and nonlinear model predictive control (NMPC) algorithm, the AMBS-P algorithm has better results for autonomous docking and undocking control, no matter in long-distance or short-distance. The research shows that the AMBS-P algorithm has a fast response and good effect for the ship autonomous docking and undocking, and does not rely too much on the system model.","Docking; Intelligent optimization algorithm; Predictive control; Ship; Undocking","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Transport Engineering and Logistics","","",""
"uuid:71a6e4c5-3555-41bd-ae25-aaf095709d68","http://resolver.tudelft.nl/uuid:71a6e4c5-3555-41bd-ae25-aaf095709d68","Structural analysis and parametric study ballasted track in sandy regions","Xiao, Hong (Beijing Jiaotong University); Zhang, Zhihai (Beijing Jiaotong University); Chi, Yihao (Beijing Jiaotong University); Wang, Xiaoyu (Beijing Jiaotong University); Wang, Haoyu (TU Delft Mechanics and Physics of Structures); Jiang, Ziqing (China Academy of Railway Sciences)","","2022","The sand intrusion in railway tracks in sandy regions can significantly change the mechanical behaviour of tracks and thus threaten the safety of train operation. This paper presents substantial field tests on both sandy and clean railway tracks to study the effect of sand intrusion on the longitudinal resistance of ballast bed and the vibration behaviour of track structures. After that, a 3D multi-scale the discrete element model is developed to study the micro-contact between ballast particles and the vibration behaviour of sandy tracks during train passing in detail. Also, the effect of train speeds and axle loads on the mechanical behaviour of sandy tracks is discussed. The results show that the sand intrusion increases the vibration acceleration amplitude of rail and sleeper by 11.3% and 50.3%, while ballast bed decreases by 44.9%. Besides, the sand intrusion significantly changes the energy distribution in the track, wherein the frequencies of the highest energy of rail and sleeper are increased while that of the ballast bed is decreased. The parametric study shows the high train speed can cause the increase in overall acceleration of the ballast bed and high axle load can cause an increase in the micro-contact forces between ballast particles, diffusion angle of the contact force chain, displacements of ballast particles, acceleration of ballast particles, and sleeper displacements.","Ballasted track; Contact force; Desert railway; Discrete element method; Vibration acceleration","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Mechanics and Physics of Structures","","",""
"uuid:92f35fb0-ea55-4a31-a37d-6c2e15e82130","http://resolver.tudelft.nl/uuid:92f35fb0-ea55-4a31-a37d-6c2e15e82130","A simple rotational spring model for laterally loaded rigid piles in sand","Wang, H. (TU Delft Geo-engineering); Lehane, B. M. (University of Western Australia); Bransby, M. F. (University of Western Australia); Askarinejad, A. (TU Delft Geo-engineering); Wang, L. Z. (Zhejiang University); Hong, Y. (Zhejiang University)","","2022","Monopiles are the most popular foundation for offshore wind turbines. These foundations typically have a low length to diameter ratio and undergo a rigid body rotation when subjected to lateral load. This paper presents results from an extensive numerical investigation involving 3D finite element analyses to demonstrate that the lateral moment-rotation response of a monopile in sand can be represented using a single non-linear rotational spring located at a depth of about 0.75 times the pile embedment. Expressions for the elastic rotational stiffness of a monopile under very low rotations are developed and these combined with observations from measured non-linear variations of rotational stiffness, that are supported by the numerical analyses, are used to develop a simple approximate expression that can be used to determine the response of a monopile to a monotonic lateral load in sand.","Hypoplastic; Lateral load; Pile-soil interaction; Rigid pile; Sands","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:92c9b2ed-9d3d-4d52-b043-3e33c63b7bf2","http://resolver.tudelft.nl/uuid:92c9b2ed-9d3d-4d52-b043-3e33c63b7bf2","Improve the long-term property of heat-cured mortars blended with fly ash by internal curing","Liu, C. (TU Delft Materials and Environment; Wuhan University of Technology); Yang, Lu (Wuhan University of Technology); Li, Z. (TU Delft Materials and Environment); Nie, Shuai (Wuhan University of Technology); Hu, Chuanlin (Wuhan University of Technology); Wang, Fazhou (Wuhan University of Technology)","","2022","Due to the satisfactory property and high productivity, heat-cured concretes have been widely used in engineering practice. However, heat curing process also brings some drawbacks that are detrimental to the long-term property of this material. To address this issue, lightweight fine aggregate (LWFA) was employed to provide internal curing (IC) for a heat-cured mortar (HCM) blended with fly ash (FA). The influences of LWFA on the interior relative humidity of HCM and the reaction environment and behavior of FA were measured. It was found that IC of LWFA could mitigate the drop of interior humidity and enhance the reaction degrees of cement and FA. This contributed significantly to the microstructure densification of HCM, higher compressive strength and better resistance to chloride ion. The results indicate that LWFA benefits to enhancing the efficiency of FA in a heat curing system and the combination of LWFA and FA contribute to improving the long-term property of HCM.","fly ash; Heat-cured mortars; Internal curing; Lightweight fine aggregate; Reaction degree; Synergistic effect","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Materials and Environment","","",""
"uuid:876aa936-ad3f-479b-a30a-0208e67d9894","http://resolver.tudelft.nl/uuid:876aa936-ad3f-479b-a30a-0208e67d9894","A multi-axis robot-based bioprinting system supporting natural cell function preservation and cardiac tissue fabrication","Zhang, Z. (University of Chinese Academy of Sciences; Chinese Academy of Sciences); Wu, Chenming (Tsinghua University); Dai, C. (TU Delft Materials and Manufacturing); Shi, Qingqing (Chinese Academy of Sciences); Fang, G. (TU Delft Materials and Manufacturing; The University of Manchester); Xie, Dongfang (Chinese Academy of Sciences); Zhao, Xiangjie (University of Chinese Academy of Sciences; Chinese Academy of Sciences); Liu, Yong Jin (Tsinghua University); Wang, C.C. (TU Delft Materials and Manufacturing; The University of Manchester); Wang, Xiu Jie (University of Chinese Academy of Sciences; Chinese Academy of Sciences)","","2022","Despite the recent advances in artificial tissue and organ engineering, how to generate large size viable and functional complex organs still remains as a grand challenge for regenerative medicine. Three-dimensional bioprinting has demonstrated its advantages as one of the major methods in fabricating simple tissues, yet it still faces difficulties to generate vasculatures and preserve cell functions in complex organ production. Here, we overcome the limitations of conventional bioprinting systems by converting a six degree-of-freedom robotic arm into a bioprinter, therefore enables cell printing on 3D complex-shaped vascular scaffolds from all directions. We also developed an oil bath-based cell printing method to better preserve cell natural functions after printing. Together with a self-designed bioreactor and a repeated print-and-culture strategy, our bioprinting system is capable to generate vascularized, contractible, and long-term survived cardiac tissues. Such bioprinting strategy mimics the in vivo organ development process and presents a promising solution for in vitro fabrication of complex organs.","3D bioprinting; Artificial organ engineering; Cardiac tissue fabrication; Print-and-culture; Six degree-of-freedom robot","en","journal article","","","","","","","","","","","Materials and Manufacturing","","",""
"uuid:881aceeb-6c6c-4d9a-916f-9a60db0196cf","http://resolver.tudelft.nl/uuid:881aceeb-6c6c-4d9a-916f-9a60db0196cf","Carbon-Iron Electron Transport Channels in Porphyrin–Graphene Complex for ppb-Level Room Temperature NO Gas Sensing","Gao, Yixun (South China Normal University); Wang, Jianqiang (South China Normal University); Feng, Yancong (South China Normal University); Cao, Nengjie (South China Normal University); Li, Hao (National Center for International Research on Green Optoelectronics; South China Normal University); de Rooij, Nicolaas Frans (South China Normal University); Umar, Ahmad (Najran University); French, P.J. (TU Delft Bio-Electronics); Wang, Yao (South China Normal University); Zhou, Guofu (South China Normal University)","","2022","It is a great challenge to develop efficient room-temperature sensing materials and sensors for nitric oxide (NO) gas, which is a biomarker molecule used in the monitoring of inflammatory respiratory diseases. Herein, Hemin (Fe (III)-protoporphyrin IX) is introduced into the nitrogen-doped reduced graphene oxide (N-rGO) to obtain a novel sensing material HNG-ethanol. Detailed XPS spectra and DFT calculations confirm the formation of carbon–iron bonds in HNG-ethanol during synthesis process, which act as electron transport channels from graphene to Hemin. Owing to this unique chemical structure, HNG-ethanol exhibits superior gas sensing properties toward NO gas (Ra/Rg = 3.05, 20 ppm) with a practical limit of detection (LOD) of 500 ppb and reliable repeatability (over 5 cycles). The HNG-ethanol sensor also possesses high selectivity against other exhaled gases, high humidity resistance, and stability (less than 3% decrease over 30 days). In addition, a deep understanding of the gas sensing mechanisms is proposed for the first time in this work, which is instructive to the community for fabricating sensing materials based on graphene-iron derivatives in the future.","carbon -iron bonds; gas sensors; graphene; Hemin; nitric oxide","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Bio-Electronics","","",""
"uuid:ece919fd-a224-490a-ba27-35092eecee75","http://resolver.tudelft.nl/uuid:ece919fd-a224-490a-ba27-35092eecee75","Lightweight design of variable-angle filament-wound cylinders combining Kriging-based metamodels with particle swarm optimization","Wang, Z. (TU Delft Aerospace Structures & Computational Mechanics; University of Electronic Science and Technology of China; Chengdu Aircraft Industrial Group Co. Ltd); Almeida, José Humberto S. (Aalto University; Queen's University Belfast); Ashok, Aravind (Student TU Delft); Wang, Zhonglai (University of Electronic Science and Technology of China); Castro, Saullo G.P. (TU Delft Aerospace Structures & Computational Mechanics)","","2022","Variable-angle filament-wound (VAFW) cylinders are herein optimized for minimum mass under manufacturing constraints, and for various design loads. A design parameterization based on a second-order polynomial variation of the tow winding angle along the axial direction of the cylinders is utilized to explore the nonlinear steering-thickness dependency in VAFW structures, whereby the thickness becomes a function of the filament steering angle. Particle swarm optimization coupled with three Kriging-based metamodels is used to find the optimum designs. A single-curvature Bogner–Fox–Schmit–Castro finite element is formulated to accurately and efficiently represent the variable stiffness properties of the shells, and verifications are performed using a general purpose plate element. Alongside the main optimization studies, a vast analysis of the design space is performed using the metamodels, showing a gap in the design space for the buckling strength that is confirmed by genetic algorithm optimizations. Extreme lightweight while buckling-resistant designs are reached, along with non-conventional optimum layouts thanks to the high degree of thickness build-up tailoring.","Buckling; Design; Filament winding; Lightweight; Mass minimization; Metamodeling; Variable stiffness; Variable-angle","en","journal article","","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:b8a74567-b256-46c8-b1c6-e83b97ce50a4","http://resolver.tudelft.nl/uuid:b8a74567-b256-46c8-b1c6-e83b97ce50a4","On the fracture behaviour of aerospace-grade Polyether-ether-ketone composite-to-aluminium adhesive joints","Quan, D. (TU Delft Structural Integrity & Composites; Shandong University); Wang, Guilong (Shandong University); Zhao, Guoqun (Shandong University); Alderliesten, R.C. (TU Delft Structural Integrity & Composites)","","2022","The inherently low surface energy of carbon fibre reinforced Polyether-ether-ketone (CF/PEEK) composites results in an extremely low compatibility with adhesives. This subsequently causes significant challenges in the adhesive joining of them to other dissimilar materials. Herein, the bonding surfaces of the CF/PEEK composites were treated by a high-power UV-irradiation technique prior to the adhesive bonding, with an attempt to develop hybrid composite-to-aluminium joints with excellent fracture resistance. The mode-I, mode-II and mix-mode fracture behaviour of CF/PEEK-to-aluminium joints bonded by two commercial aerospace adhesives was evaluated. Cohesive failure within the adhesive layers or substrate damage to the CF/PEEK composites were observed in all the cases. This indicated that the adhesion between the CF/PEEK composites and the adhesives was sufficient to prevent an adhesive failure at the composite/adhesive interfaces under different fracture modes. This study explored an effective route to develop strong and tough CF/PEEK-to-aluminium joints for aerospace applications. Additionally, it revealed that the form of the adhesive supporting carrier was a key factor affecting the fracture behaviour and fracture energies of the adhesive joints.","Adhesive joining; Aerospace composite-to-metal joints; Fracture behaviour; Surface treatment","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-09-01","","","Structural Integrity & Composites","","",""
"uuid:1b17a5c1-88f6-47d6-b25e-0340eb05dbe8","http://resolver.tudelft.nl/uuid:1b17a5c1-88f6-47d6-b25e-0340eb05dbe8","Tailoring precipitation/properties and related mechanisms for a high-strength aluminum alloy plate via low-temperature retrogression and re-aging processes","Hou, L. G. (University of Science and Technology Beijing; Brunel University; Nanjing Advanced Transportation Equipment New Technology Research Institute); Yu, H. (Chinese Academy of Geological Sciences); Wang, Y. W. (University of Science and Technology Beijing); You, L. (University of Science and Technology Beijing); He, Z. B. (University of Science and Technology Beijing); Wu, C. M. (Nanjing Advanced Transportation Equipment New Technology Research Institute); Eskin, D. G. (Brunel University; National Research Tomsk State University); Katgerman, L. (TU Delft Team Kevin Rossi; Katgerman Aluminium Technology); Zhuang, L. Z. (University of Science and Technology Beijing); Zhang, J. S. (University of Science and Technology Beijing)","","2022","The retrogression and re-aging (RRA) processes, aimed mainly at tailoring intergranular precipitates, could significantly improve the corrosion resistance (i.e., stress corrosion cracking resistance) without considerably decreasing the strength, which signifies that an efficient control of the size, distribution and evolution of intergranular and intragranular precipitates becomes critical for the integrated properties of the (mid-)thick high-strength Al alloy plates. Compared to RRA process with retrogression at 200 °C (T77), this study investigated the impact of a modified RRA process (MT77) with lower retrogression temperatures (155-175 °C) and first-stage under-aging on the properties of a high-strength AA7050 Al alloy, in combination with detailed precipitate characterization. The study showed that the strength/microhardness of the RRA-treated alloys decreased with raising retrogression temperature and/or prolonging retrogression time, along with the increased electrical conductivity. The rapid responsiveness of microstructure/property typical of retrogression at 200 °C was obviously postponed or decreased by using MT77 process with longer retrogression time that was more suitable for treating the (mid-)thick plates. On the other hand, higher retrogression temperature facilitated more intragranular η precipitates, coarse intergranular precipitates and wide precipitate free zones, which prominently increased the electrical conductivity alongside a considerable strength loss as compared to the MT77-treated alloys. With the preferred MT77 process, the high strength approaching T6 level as well as good corrosion resistance was achieved. However, though a relatively homogeneous through-thickness strength was obtained, some small discrepancies of properties between the central and surface areas of an 86-mm thick 7050 Al alloy plate were observed, possibly related to the quenching sensitivity. The precipitate evolution and mechanistic connection to the properties were discussed and reviewed for high-strength Al alloys along with suggestions for further RRA optimization.","Aluminum alloy; Grain boundary; Heat treatment; Precipitation; Strength","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-09-09","","","Team Kevin Rossi","","",""
"uuid:0d578c70-705e-4411-9990-c38fc5e335e6","http://resolver.tudelft.nl/uuid:0d578c70-705e-4411-9990-c38fc5e335e6","Nanomechanical Characteristics of Interfacial Transition Zone in Nano-Engineered Concrete","Wang, Xinyue (Dalian University of Technology); Dong, Sufen (Dalian University of Technology); Li, Z. (TU Delft Materials and Environment); Han, Baoguo (Dalian University of Technology); Ou, Jinping (Dalian University of Technology)","","2022","This study investigates the effects of nanofillers on the interfacial transition zone (ITZ) between aggregate and cement paste by using nanoindentation and statistical nanoindentation techniques. Moreover, the underlying mechanisms are revealed through micromechanical modeling. The nanoindentation results indicate that incorporating nanofillers increases the degree of hydration in the ITZ, reduces the content of micropores and low-density calcium silicate hydrate (LD C–S–H), and increases the content of high-density C–S–H (HD C–S–H) and ultrahigh-density C–S–H (UHD C–S–H). In particular, a new phase, namely nano-core-induced low-density C–S–H (NCILD C–S–H), with a superior hardness of 2.50 GPa and an indentation modulus similar to those of HD C–S–H or UHD C–S–H was identified in this study. The modeling results revealed that the presence of nanofillers increased the packing density of LD C–S–H and significantly enhanced the interaction (adhesion and friction) among the basic building blocks of C–S–H gels owing to the formation of nano-core–shell elements, thereby facilitating the formation of NCILD C–S–H and further improving the performance of the ITZ. This study provides insight into the effects of nanofillers on the ITZ in concrete at the nanoscale.","Concrete; Interfacial transition zone; Micromechanical modeling; Nano-core effect; Nanofiller; Nanoindentation","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:61bdb7ab-c737-4f3a-b60a-0ab6e9fd7fff","http://resolver.tudelft.nl/uuid:61bdb7ab-c737-4f3a-b60a-0ab6e9fd7fff","Unraveling competition versus adsorbability of dissolved organic matter against organic micropollutants onto activated carbon","Wang, Q. (TU Delft Sanitary Engineering; Chinese Academy of Sciences; University of Chinese Academy of Sciences); Zietzschmann, F.E. (TU Delft Sanitary Engineering; Berliner Wasserbetriebe); Hofman-Caris, Roberta (KWR Water Research Institute); Jiang, N. (TU Delft Sanitary Engineering); Schuster, Jonas (Hamburg University of Technology); Wang, Zheng (Shanghai National Engineering Research Center of Urban Water Resources); Yu, Jianwei (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Yang, Min (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Rietveld, L.C. (TU Delft Water Management)","","2022","It was widely acknowledged that dissolved organic matter (DOM) in natural water has ubiquitous competitiveness against organic micropollutants (OMPs) during adsorption onto activated carbon. However, some (model) low molecular weight organics have been reported to adsorb onto activated carbon, but were not competitive against co-adsorbates. The objective of this study is to identify which adsorbable DOM fractions in natural water contribute to the DOM competitiveness, and what is the impact of the OMP adsorbability and initial OMP concentration on this competitiveness. We, therefore, disassociated the adsorption of DOM fractions and OMPs (carbamazepine, caffeine and sulfamethoxazole) using a two-stage adsorption procedure, removing various adsorbable DOM fractions with powdered activated carbon pretreatment and then unraveling the competitiveness against OMPs of the remaining DOM. Our results demonstrated that DOM competition was not ubiquitous for all adsorbable fractions in natural water, and ∼ 25% of the adsorbable DOM was not competitive. The poorly adsorbable DOM was shown to be a non-competitive co-adsorbate, and its complexation even elevated the adsorption capacity of one of the OMPs (carbamazepine). The amount of DOM competitors increased for weaker adsorbable OMPs, and at higher initial OMP concentrations. The variability in DOM competition, differentiated by DOM adsorbability, has advanced the understanding of DOM competition, from ubiquitous competition to variable roles (varying competitiveness/complementary adsorption) of differently adsorbable DOM fractions during OMP adsorption.","Activated carbon; Adsorbability; Adsorption isotherm; Competitive adsorption; Dissolved organic matter (DOM)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-09-28","","Water Management","Sanitary Engineering","","",""
"uuid:8c131585-c91e-4407-ad3e-329f1e05546c","http://resolver.tudelft.nl/uuid:8c131585-c91e-4407-ad3e-329f1e05546c","Plasmon resonance based gold nanoparticle doped optical fibre strain sensing","Wang, X. (TU Delft Structural Integrity & Composites); Benedictus, R. (TU Delft Structural Integrity & Composites); Groves, R.M. (TU Delft Structural Integrity & Composites)","","2022","Strain-based structural health monitoring (SHM) relies on high performance strain sensing methods. Gold nanoparticle (NP) doped fibre optic sensors not only have the potential to increase the intensity of the backscattered signal to increase the signal to noise ratio but also have plasmon resonance peaks in the visible light range. The spectral peak shift of the plasmon resonance may be used for strain sensing. In this paper, the spectral peak shift of the plasmon resonance of an optical fibre containing gold NPs under axial strain was analysed. A modified Lorentz-Drude (LD) model with the T-matrix method was used and the spectral peak shifts of spheroidal NPs under strain were calculated. An approximate analytical expression was derived for faster calculation. The modelling presented in this paper shows that the ratio of the change of the peak wavelength to the strain can be related to the refractive index (RI) change of the optical fibre under strain, the shape change of the gold NP, and the RI change of the gold NP. The peak shift was also observed experimentally in an optical adhesive containing gold NPs under compression. The peak shifts were analysed at different RI of the optical fibres, 1.35, 1.45, 1.55 and 1.65 respectively, in order to cover the range of RI of fused silica and some polymer materials. The results confirm experimentally that the applied axial strain can induce the peak wavelength shift by the NPs. By choosing a different optical fibre or the properties of the NPs, the wavelength change ratio has the potential to be tuned, which may be used for highly sensitive strain sensing.","Gold nanoparticle; Optical fibre; Plasmon resonance; Strain sensing","en","journal article","","","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:bde655ee-4d45-45e4-a976-4fc948f67c9a","http://resolver.tudelft.nl/uuid:bde655ee-4d45-45e4-a976-4fc948f67c9a","Resilience-based approach to maintenance asset and operational cost planning","Sun, Hao (China University of Petroleum (East China)); Yang, M. (TU Delft Safety and Security Science); Wang, Haiqing (China University of Petroleum (East China))","","2022","Reliability-based and risk-based methods for directing maintenance activities play a critical role in ensuring system safety and reducing unnecessary downtime. Those methods focus on preventive maintenance to avoid component failures and are applicable before unexpected disruptions occur. However, when disruptions are unavoidable, more attention should be paid to systems’ recovery from unwanted changes. As a remedy of preventive maintenance, improving system restoration capacity of resilience through optimizing the system's maintenance asset and operational cost is an efficient way to help system restore from disruption conditions within an optimal cost. In this paper, a resilience-based approach is proposed to optimize maintenance asset and operational cost. A novel resilience metric is developed and utilized to quantify system resilience under various restoration capacities. The minimal acceptable resilience level (MARL) and maximal acceptable restoration time (MART) are proposed to determine the optimal maintenance cost. The proposed approach is applied to the Chevron Richmond refinery crude unit and its upstream process. The results show that it can help practitioners identify the optimal cost to ensure a system is resilient to respond to uncertain disruptions and provide a dynamic resilience profile to support decision-making.","Cost optimization; Maintenance; Process systems; Resilience; Restoration","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:162aa566-fb73-42c0-acd6-cc0a236a2aaa","http://resolver.tudelft.nl/uuid:162aa566-fb73-42c0-acd6-cc0a236a2aaa","Electrochemical CO2 reduction in membrane-electrode assemblies","Ge, Lei (University of Queensland); Rabiee, Hesamoddin (University of Queensland); Li, Mengran (TU Delft ChemE/Materials for Energy Conversion and Storage; University of Queensland); Subramanian, S.S. (TU Delft ChemE/Materials for Energy Conversion and Storage); Zheng, Yao (University of Adelaide); Lee, Joong Hee (Chonbuk National University); Burdyny, T.E. (TU Delft ChemE/Materials for Energy Conversion and Storage); Wang, H. (University of Southern Queensland)","","2022","Electrochemical conversion of gaseous CO2 to value-added products and fuels is a promising approach to achieve net-zero CO2 emission energy systems. Significant efforts have been achieved in the design and synthesis of highly active and selective electrocatalysts for this reaction and their reaction mechanism. To perform an efficient conversion and desired product selectivity in practical applications, we need an active, cost-effective, stable, and scalable electrolyzer design. Membrane-electrode assemblies (MEAs) can be an efficient solution to address the key challenges in the aqueous gas diffusion electrodes (GDE), e.g., ohmic resistances and complex reactor design. This review presents a critical overview of recent advances in experimental design and simulation of MEAs for CO2 reduction reaction, including the shortcomings and remedial strategies. In the last section, the remaining challenges and future research opportunities are suggested to support the advancement of CO2 electrochemical technologies.","electrochemical CO reduction reaction; electrolyzer design; gas diffusion electrodes; membrane-electrode assemblies","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:ee141599-048d-401d-8e6c-567df18822a0","http://resolver.tudelft.nl/uuid:ee141599-048d-401d-8e6c-567df18822a0","The field-free Josephson diode in a van der Waals heterostructure","Wu, H. (TU Delft QN/Ali Lab; Max Planck Institute of Microstructure Physics; Shenzhen University; Kavli institute of nanoscience Delft); Wang, Y. (TU Delft QN/Ali Lab; Max Planck Institute of Microstructure Physics; Kavli institute of nanoscience Delft); Xu, Y. (Max Planck Institute of Microstructure Physics; Princeton University); Sivakumar, Pranava K. (Max Planck Institute of Microstructure Physics); Pasco, Chris (Johns Hopkins University); Filippozzi, U. (TU Delft QN/Caviglia Lab; Kavli institute of nanoscience Delft); Parkin, Stuart S.P. (Max Planck Institute of Microstructure Physics); Zeng, Y. (Shenzhen University); McQueen, Tyrel (Johns Hopkins University); Ali, M.N. (TU Delft QN/Ali Lab; Max Planck Institute of Microstructure Physics; Kavli institute of nanoscience Delft)","","2022","The superconducting analogue to the semiconducting diode, the Josephson diode, has long been sought with multiple avenues to realization being proposed by theorists1–3. Showing magnetic-field-free, single-directional superconductivity with Josephson coupling, it would serve as the building block for next-generation superconducting circuit technology. Here we realized the Josephson diode by fabricating an inversion symmetry breaking van der Waals heterostructure of NbSe2/Nb3Br8/NbSe2. We demonstrate that even without a magnetic field, the junction can be superconducting with a positive current while being resistive with a negative current. The ΔIc behaviour (the difference between positive and negative critical currents) with magnetic field is symmetric and Josephson coupling is proved through the Fraunhofer pattern. Also, stable half-wave rectification of a square-wave excitation was achieved with a very low switching current density, high rectification ratio and high robustness. This non-reciprocal behaviour strongly violates the known Josephson relations and opens the door to discover new mechanisms and physical phenomena through integration of quantum materials with Josephson junctions, and provides new avenues for superconducting quantum devices.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-10-27","","","QN/Ali Lab","","",""
"uuid:f3ac4956-f744-47c9-87ad-379ff9dddc86","http://resolver.tudelft.nl/uuid:f3ac4956-f744-47c9-87ad-379ff9dddc86","IGA-Reuse-NET: A deep-learning-based isogeometric analysis-reuse approach with topology-consistent parameterization[Formula presented]","Wang, Dandan (Hangzhou Dianzi University); Xu, Jinlan (Hangzhou Dianzi University); Gao, Fei (Hangzhou Dianzi University); Wang, C.C. (TU Delft Materials and Manufacturing; The University of Manchester); Gu, Renshu (Hangzhou Dianzi University); Lin, Fei (Hangzhou Dianzi University); Rabczuk, Timon (Bauhaus University Weimar); Xu, Gang (Hangzhou Dianzi University)","","2022","In this paper, a deep learning framework combined with isogeometric analysis (IGA for short) called IGA-Reuse-Net is proposed for efficient reuse of numerical simulation on a set of topology-consistent models. Compared with previous data-driven numerical simulation methods only for simple computational domains, our method can predict high-accuracy PDE solutions over topology-consistent geometries with complex boundaries. UNet3+ architecture with interlaced sparse self-attention (ISSA) module is used to enhance the performance of the network. In addition, we propose a new loss function that combines a coefficients loss and a numerical solution loss. Several training datasets with topology-consistent models are constructed for the proposed framework. To verify the effectiveness of our approach, two different types of Poisson equations with different source functions are solved on three datasets with different topologies. Our framework can achieve a good trade-off between accuracy and efficiency. It outperforms the physics-informed neural network (PINN for short) model and yields promising results of prediction.","Analysis-reuse; CAD/CAE integration; Deep learning; Isogeometric analysis; Topology-consistent model","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Materials and Manufacturing","","",""
"uuid:a99cf48b-bcee-44c0-bbc2-9ba9b82aa1cd","http://resolver.tudelft.nl/uuid:a99cf48b-bcee-44c0-bbc2-9ba9b82aa1cd","Parameter estimation for a global tide and surge model with a memory-efficient order reduction approach","Wang, X. (TU Delft Mathematical Physics); Verlaan, M. (TU Delft Mathematical Physics; Deltares); Apecechea, Maialen Irazoqui (Deltares); Lin, H.X. (TU Delft Mathematical Physics)","","2022","Accurate parameter estimation for the Global Tide and Surge Model (GTSM) benefits from observations with long time-series. However, increasing the number of measurements leads to a large computation demand and increased memory requirements, especially for the ensemble-based methods that assimilate the measurements at one batch. In this study, a memory-efficient parameter estimation scheme using model order reduction in time patterns is developed for a high-resolution global tide model. We propose using projection onto empirical time-patterns to reduce the model output time-series to a much smaller linear subspace. Then, to further improve the estimation accuracy, we introduce an outer-loop, similar to Incremental 4D-VAR, to evaluate model-increments at a lower resolution and subsequently reduce the computational cost. The inner-loop optimizes parameters using the lower-resolution model and an iterative least-squares estimation algorithm called DUD. The outer-loop updates the initial output from the high-resolution model with updated parameters from the converged inner-loop and then restarts the inner-loop. We performed experiments to adjust the bathymetry with observations from the FES2014 dataset. Results show that the time patterns of the tide series can be successfully projected to a lower dimensional subspace, and memory requirements are reduced by a factor of 22 for our experiments. The estimation is converged after three outer iterations in our experiment, and tide representation is significantly improved, achieving a 34.5% reduction of error. The model's improvement is not only shown for the calibration dataset, but also for several validation datasets consisting of one year of time-series from FES2014 and UHSLC tide gauges.","Global tide and surge model; Model order reduction; Parameter estimation","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:1307dc99-0c01-4a43-b182-500ec9367435","http://resolver.tudelft.nl/uuid:1307dc99-0c01-4a43-b182-500ec9367435","Assessment of ballast layer under multiple field conditions in China","Guo, Y. (TU Delft Railway Engineering); Wang, Shilei (China Academy of Railway Sciences); Jing, Guoqing (Beijing Jiaotong University); Yang, Fei (China Academy of Railway Sciences); Liu, Guixian (China Academy of Railway Sciences); Qiang, Weile (China Academy of Railway Sciences); Wang, Yan (China Academy of Railway Sciences)","","2022","Ballast layer condition should be more regularly and accurately inspected to ensure safe train operation; however, traditional inspection methods cannot sufficiently fulfil this task. This paper presents a method of ground penetrating radar (GPR) application to reflect ballast layer fouling levels under diverse field conditions (annual gross passing load, cleaning and renewal year, fouling composition and transportation type). The results show that the GPR-based inspection method can assess the ballast layer fouling level with a 1–7% difference from the traditional sieving results. Fouling composition (especially metal materials) has a great effect on the GPR signals, thus affecting the inspection accuracy of ballast layer fouling level. Developing diverse GPR-based fouling indicators (by distinguishing different GPR signal features) can improve the GPR inspection applicability to the diverse field conditions.","Ballast fouling; GPR; Ground penetrating radar; Railway ballast; Track geometry; Track inspection","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Railway Engineering","","",""
"uuid:ff2aa341-26fd-42b1-b033-f8ef562051dc","http://resolver.tudelft.nl/uuid:ff2aa341-26fd-42b1-b033-f8ef562051dc","Isotopic Exchange Study on the Kinetics of Fe Carburization and the Mechanism of the Fischer-Tropsch Reaction","Chai, Jiachun (Eindhoven University of Technology); Pestman, Robert (Eindhoven University of Technology); Chen, Wei (Eindhoven University of Technology); Donkervoet, Noortje (Eindhoven University of Technology); Dugulan, A.I. (TU Delft RID/TS/Instrumenten groep); Men, Zhuowu (National Institute of Clean-and-Low-Carbon Energy, Shenhua NICE, Future Science and Technology City, Changping District, Beijing 102211, People's Republic of China); Wang, Peng (Eindhoven University of Technology; National Institute of Clean-and-Low-Carbon Energy, Shenhua NICE, Future Science and Technology City, Changping District, Beijing 102211, People's Republic of China); Hensen, Emiel J.M. (Eindhoven University of Technology)","","2022","The kinetics of the transformation of metallic Fe to the active Fe carbide phase at the start of the Fischer-Tropsch (FT) reaction were studied. The diffusion rates of C atoms going in or out of the lattice were determined using 13C-labeled synthesis gas in combination with measurements of the transient 12C and 13C contents in the carbide by temperature-programmed hydrogenation. In the initial 20 min, C diffuses rapidly into the lattice occupying thermodynamically very stable interstitial sites. The FT reaction starts already during these early stages of carburization. When reaching steady state, the diffusion rates of C in and out of the lattice converge and the FT reaction continues via two parallel reaction mechanisms. It appears that the two outer layers of the Fe carbide are involved in hydrocarbon formation via a slow Mars-Van Krevelen-like reaction contributing to ∼10% of the total activity, while the remainder of the activity stems from a fast Langmuir-Hinshelwood reaction occurring over a minor part of the catalyst surface.","carburization; Fe carbide; Fischer-Tropsch reaction; isotopes; mechanism","en","journal article","","","","","","","","","","","RID/TS/Instrumenten groep","","",""
"uuid:cdeb396c-838a-4369-b921-fb626a2c9dc5","http://resolver.tudelft.nl/uuid:cdeb396c-838a-4369-b921-fb626a2c9dc5","Simulation of Poyang Lake water levels and outflow under historical extreme hydrological scenarios","Yu, M. (TU Delft Water Resources; Hohai University; Nanjing Hydraulic Research Institute); Liu, X. (TU Delft Hydraulic Structures and Flood Risk; Southeast University; IHE Delft Institute for Water Education); Wood, Paul (Loughborough University); Wei, Li (Hydrology Monitoring Center of Jiangxi Province, Nanchang); Wang, Guoqing (Nanjing Hydraulic Research Institute); Zhang, Jianyun (Nanjing Hydraulic Research Institute); Li, Qiongfang (Hohai University)","","2022","Due to an intensification of anthropogenic activities and climate change in recent decades, the hydrological connections and relationships between rivers and lakes have been significantly modified globally. Poyang Lake is one of the largest freshwater lakes globally and is one of the few that remain naturally connected to the Yangtze River. To investigate the full hydrological conditions (extreme high and low discharge) of Poyang Lake outflow under current bathymetric conditions, a large-scale 1D- and 2D-coupled high-resolution hydrodynamic model of the Poyang Lake basin–Yangtze River system was developed. We simulated the outflow and water levels of Poyang Lake under nine different extreme hydrological scenarios with high precision and computational efficiency. We propose (1) a novel partition calibration method to characterize the roughness coefficient of large water bodies in complicated geographical terrain both for wet and dry seasons; (2) a new method for setting initial conditions for hydrodynamic simulation of large water bodies subject to strong hydrological regulation. Results indicated that (1) maximum outflow and water levels will reach 37,200 m3/s and 22.28 m when Poyang Lake basin floodwater coincides with flooding on the Yangtze River; (2) precipitation over the lake has increased outflow but this has had very limited influence on its changing hydrological pattern; (3) the effect of hydrological conditions within the system differs for both the lake outflow and water level. The research provides important reference conditions for the application of the InfoWorks ICM model in future applications and studies of large river–lake systems.","flood and drought; hydrodynamic model; outflow; Poyang Lake; rainfall; Yangtze River","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:866554ba-21c8-41aa-8ed5-e3de1400df9f","http://resolver.tudelft.nl/uuid:866554ba-21c8-41aa-8ed5-e3de1400df9f","Spectroscopic thermo-elastic optical coherence tomography for tissue characterization","Deen, Aaron Doug (Erasmus MC); van Beusekom, Heleen M.M. (Erasmus MC); Pfeiffer, Tom (University of Lübeck); Stam, Mathijs (Erasmus MC); Kleijn, Dominique D.E. (University Medical Center Utrecht); Wentzel, Jolanda (Erasmus MC); Huber, Robert (University of Lübeck); van der Steen, A.F.W. (TU Delft ImPhys/Medical Imaging; Erasmus MC; Chinese Academy of Sciences); Van Soest, Gijs (Erasmus MC); Wang, Tianshi (Erasmus MC)","","2022","Optical imaging techniques that provide free space, label free imaging are powerful tools in obtaining structural and biochemical information in biological samples. To date, most of the optical imaging technologies create images with a specific contrast and require multimodality integration to add additional contrast. In this study, we demonstrate spectroscopic Thermo-elastic Optical Coherence Tomography (TE-OCT) as a potential tool in tissue identification. TE-OCT creates images based on two different forms of contrast: optical reflectance and thermo-elastic deformation. TE-OCT uses short laser pulses to induce thermo-elastic tissue deformation and measures the resulting surface displacement using phase-sensitive OCT. In this work we characterized the relation between thermo-elastic displacement and optical absorption, excitation, fluence and illumination area. The experimental results were validated with a 2-dimensional analytical model. Using spectroscopic TE-OCT, the thermo-elastic spectra of elastic phantoms and tissue components in coronary arteries were extracted. Specific tissue components, particularly lipid, an important biomarker for identifying atherosclerotic lesions, can be identified in the TE-OCT spectral response. As a label-free, free-space, dual-contrast, all-optical imaging technique, spectroscopic TE-OCT holds promise for biomedical research and clinical pathology diagnosis.","","en","journal article","","","","","","The formatting of the first, fifth, and ninth authors’ surnames in this paper [1] has been corrected. The paper [1] was corrected on 11 May 2022.","","","","","ImPhys/Medical Imaging","","",""
"uuid:35c0dcac-5a5d-40ad-8216-231f265353ac","http://resolver.tudelft.nl/uuid:35c0dcac-5a5d-40ad-8216-231f265353ac","A comparison between alkali-activated slag/fly ash binders prepared with natural seawater and deionized water","Ren, Jie (Shenzhen University; University of Colorado); Sun, Hongfang (Shenzhen University); Li, Qun (Shenzhen University); Li, Z. (TU Delft Materials and Environment); Zhang, Xiaogang (Shenzhen University); Wang, Yanshuai (Shenzhen University); Li, Linfei (University of Colorado); Xing, Feng (Shenzhen University)","","2022","In this research, the effects of natural seawater (SW) on the properties of alkali-activated slag/fly ash (AASF) are studied. AASF prepared with deionized water is set as the reference mixture. The results showed that the use of natural SW resulted in a prolonged setting time and lower heat release, but no obvious impact on the flowability of AASF specimens. The long-term compressive strength became higher when SW was used, whereas the corresponding flexural strength and fractural toughness turned lower. The use of SW induced the formation of new products that were not identified in the reference mixture, such as Cl–hydrocalumite and gypsum. In addition, it is evidenced that the dissolution of fly ash (FA) particles was significantly delayed with the incorporation of SW. All these results were related to the various ions introduced by the natural SW and their interactions with the alkaline activator as well as the precipitation of salts on slag and FA surfaces or in the matrix.","alkali-activated slag/fly ash; hydration kinetics; mechanical properties; microstructure; seawater; setting time","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:3bbaa07a-58eb-4443-b5df-f88301aa8ce6","http://resolver.tudelft.nl/uuid:3bbaa07a-58eb-4443-b5df-f88301aa8ce6","More efficient enzymatic cascade reactions by spatially confining enzymes via the SpyTag/SpyCatcher technology","Zhong, Xuanru (South China University of Technology); Ma, Yunjian (South China University of Technology; Macau University of Science and Technology); Zhang, Xizhen (South China University of Technology); Zhang, Jiahui (South China University of Technology); Wu, Bin (South China University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Yonghua (South China University of Technology; Guangdong Youmei Institute of Inteligent Bio-manufacturing Co, Guangdong)","","2022","Hydrocarbon synthesis from (waste)oils enabled by a cascade of lipase-catalysed hydrolysis and decarboxylase-catalysed decarboxylation has become an active area of research en route to alternative, biobased fuels. However, Poor substrate transport efficiency is a major issue causing low reaction rates. This study focused on a protein self-assembly strategy based on SpyTag/SpyCatcher to overcome diffusion limitations. For this, two fusion proteins, TLL-Linker-SpyCatcher based on the lipase from Thermomyces lanuginosus and CvFAP-Linker-SpyTag based on the fatty acid photodecarboxylase from Chlorella variabilis were designed. A covalent multi-enzyme complex (TLL-CvFAP) was formed spontaneously by self-assembly of each enzyme. The effects of temperature, pH and molar ratio of self-assembled components on assembly efficiency were investigated. The results showed that the multi-enzyme complex TLL-CvFAP reached about 60% after 12 h of assembly, and the enzyme activity of the multienzyme complex was increased by about 50% compared to that of the corresponding non-assembled enzymes. Under optimized conditions 10 mM soybean oil were converted into 25 mM of the corresponding hydrocarbons, suggesting a good potential of biofuel synthesis.","CvFAP; Hydrocarbon biofuels; Multienzyme complex; SpyTag/SpyCatcher; TLL","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-08-23","","","BT/Biocatalysis","","",""
"uuid:24f9bde5-a689-4388-86d9-168afe814e8e","http://resolver.tudelft.nl/uuid:24f9bde5-a689-4388-86d9-168afe814e8e","On the durability of surgical masks after simulated handling and wear","Varanges, Vincent (Swiss Federal Institute of Technology); Caglar, Baris (TU Delft Aerospace Manufacturing Technologies; Swiss Federal Institute of Technology); Lebaupin, Yann (Swiss Federal Institute of Technology); Batt, Till (Swiss Federal Laboratories for Materials Science and Technology (Empa)); He, Weidong (Swiss Federal Laboratories for Materials Science and Technology (Empa); ETH Zürich); Wang, Jing (Swiss Federal Laboratories for Materials Science and Technology (Empa); ETH Zürich); Rossi, René M. (Swiss Federal Laboratories for Materials Science and Technology (Empa)); Richner, Gilles (Federal Office for Civil Protection FOCP); Delaloye, Jean Romain (Kantonsspital Winterthur); Michaud, Véronique (Swiss Federal Institute of Technology)","","2022","After the spread of COVID-19, surgical masks became highly recommended to the public. They tend to be handled and used multiple times, which may impact their performance. To evaluate this risk, surgical masks of Type IIR were submitted to four simulated treatments: folding, ageing with artificial saliva or sweat and washing cycles. The air permeability, mechanical integrity, electrostatic potential, and filtration efficiency (FE) of the masks were measured to quantify possible degradation. Overall, air permeability and mechanical integrity were not affected, except after washing, which slightly degraded the filtering layers. Electrostatic potential and FE showed a strong correlation, highlighting the role of electrostatic charges on small particle filtration. A slight decrease in FE for 100 nm particles was found, from 74.4% for the reference masks to 70.6% for the mask treated in saliva for 8 h. A strong effect was observed for washed masks, resulting in FE of 46.9% (± 9.5%), comparable to that of a control group with no electrostatic charges. A dry store and reuse strategy could thus be envisaged for the public if safety in terms of viral and bacterial charge is ensured, whereas washing strongly impacts FE and is not recommended.","","en","journal article","","","","","","","","","","","Aerospace Manufacturing Technologies","","",""
"uuid:9d15ad46-f500-4b3a-bc02-50c87dd1e3b7","http://resolver.tudelft.nl/uuid:9d15ad46-f500-4b3a-bc02-50c87dd1e3b7","A literature review of Artificial Intelligence applications in railway systems","Tang, Ruifan (University of Leeds); De Donato, Lorenzo (Università degli Studi di Napoli Federico II); Bešinović, Nikola (TU Delft Transport and Planning); Flammini, Francesco (Linnaeus University; Mälardalen University); Goverde, R.M.P. (TU Delft Transport and Planning); Lin, Zhiyuan (University of Leeds); Liu, Ronghui (University of Leeds); Tang, Tianli (University of Leeds; Southeast University); Vittorini, Valeria (Università degli Studi di Napoli Federico II); Wang, Z. (TU Delft Transport and Planning)","","2022","Nowadays it is widely accepted that Artificial Intelligence (AI) is significantly influencing a large number of domains, including railways. In this paper, we present a systematic literature review of the current state-of-the-art of AI in railway transport. In particular, we analysed and discussed papers from a holistic railway perspective, covering sub-domains such as maintenance and inspection, planning and management, safety and security, autonomous driving and control, revenue management, transport policy, and passenger mobility. This review makes an initial step towards shaping the role of AI in future railways and provides a summary of the current focuses of AI research connected to rail transport. We reviewed about 139 scientific papers covering the period from 2010 to December 2020. We found that the major research efforts have been put in AI for rail maintenance and inspection, while very limited or no research has been found on AI for rail transport policy and revenue management. The remaining sub-domains received mild to moderate attention. AI applications are promising and tend to act as a game-changer in tackling multiple railway challenges. However, at the moment, AI research in railways is still mostly at its early stages. Future research can be expected towards developing advanced combined AI applications (e.g. with optimization), using AI in decision making, dealing with uncertainty and tackling newly rising cybersecurity challenges.","Artificial Intelligence; Autonomous driving; Machine Learning; Maintenance; Railways; Smart mobility; Traffic management; Train control; Transportation","en","review","","","","","","","","","","","Transport and Planning","","",""
"uuid:2a20368f-c8a6-4839-8cd1-0b87a7ce6c65","http://resolver.tudelft.nl/uuid:2a20368f-c8a6-4839-8cd1-0b87a7ce6c65","A two-dimensional ordinary state-based peridynamic model for surface fatigue crack propagation in railheads","Ma, Xiaochuan (East China Jiaotong University); Wang, L. (TU Delft Railway Engineering); Xu, Jinhui (East China Jiaotong University); Feng, Qingsong (East China Jiaotong University); Liu, Linya (East China Jiaotong University); Chen, Huapeng (East China Jiaotong University)","","2022","Based on ordinary state-based peridynamic theory, a 2D peridynamic model has been established to investigate fatigue crack propagation in railheads. The proposed model is verified in terms of rail deformation under a quasi-static load and the ductile material-related fatigue failure model. Good agreements have been achieved between a finite element model and the experimental results. With the proposed model, the effects of the initial crack angle, initial crack length and wheel-rail friction coefficient on crack propagation in railheads are studied. This research provides a new method for studying crack propagation in railheads.","Crack propagation; Fatigue; Peridynamic model; Railway; Wheel-rail contact","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-08-28","","","Railway Engineering","","",""
"uuid:2e3d15f7-775d-4c7a-bf2b-5668ec5285fb","http://resolver.tudelft.nl/uuid:2e3d15f7-775d-4c7a-bf2b-5668ec5285fb","Modelling perceived risk and trust in driving automation reacting to merging and braking vehicles","He, X. (TU Delft Intelligent Vehicles); Stapel, J.C.J. (TU Delft Intelligent Vehicles); Wang, M. (Technische Universität Dresden); Happee, R. (TU Delft Intelligent Vehicles)","","2022","Perceived risk and trust are crucial for user acceptance of driving automation. In this study, we identify important predictors of perceived risk and trust in a driving simulator experiment and develop models through stepwise regression to predict event-based changes in perceived risk and trust. 25 participants were tasked to monitor SAE Level 2 driving automation (ACC + LC) while experiencing merging and hard braking events with varying criticality on a motorway. Perceived risk and trust were rated verbally after each event, and continuous perceived risk, pupil diameter and ECG signals were explored as possible indictors for perceived risk and trust. The regression models show that relative motion with neighbouring road users accounts for most perceived risk and trust variations, and no difference was found between hard braking with merging and hard braking without merging. Drivers trust the automation more in the second exposure to events. Our models show modest effects of personal characteristics: experienced drivers are less sensitive to risk and trust the automation more, while female participants perceive more risk than males. Perceived risk and trust highly correlate and have similar determinants. Continuous perceived risk accurately reflects participants’ verbal post-event rating of perceived risk; the use of brakes is an effective indicator of high perceived risk and low trust, and pupil diameter correlates to perceived risk in the most critical events. The events increased heart rate, but we found no correlation with event criticality. The prediction models and the findings on physiological measures shed light on the event-based dynamics of perceived risk and trust and can guide human-centred automation design to reduce perceived risk and enhance trust.","Automated driving; ECG; Perceived risk; Prediction models; Pupil dilation; Trust","en","journal article","","","","","","","","","","","Intelligent Vehicles","","",""
"uuid:f9b807f2-ffd7-4b3e-84ef-a68d93058129","http://resolver.tudelft.nl/uuid:f9b807f2-ffd7-4b3e-84ef-a68d93058129","Carbon Dots Embedded in Cellulose Film: Programmable, Performance-Tunable, and Large-Scale Subtle Fluorescent Patterning by in Situ Laser Writing","Guo, Yuanyuan (South China Normal University); Wang, Quan (South China Normal University); LI, H. (South China Normal University); Gao, Yixun (South China Normal University); Xu, Xuezhu (South China Normal University); Tang, Biao (South China Normal University); Yang, B. (Jilin University); Lee, Yi Kuen (The Hong Kong University of Science and Technology); French, P.J. (TU Delft Bio-Electronics)","","2022","Fluorescent patterns with multiple functions enable high-security anti-counterfeiting labels. Complex material synthesis and patterning processes limit the application of multifunctional fluorescent patterns, so the technology of in situ fluorescent patterning with tunable multimodal capabilities is becoming more necessary. In this work, an in situ fluorescent patterning technology was developed using laser direct writing on solid cellulose film at ambient conditions without masks. The fluorescent intensity and surface microstructure of the patterns could be adjusted by programmable varying of the laser parameters simultaneously. During laser direct writing, carbon dots are generated in situ in a cellulose ester polymer matrix, which significantly simplifies the fluorescent patterning process and reduces the manufacturing cost. Interestingly, the tunable fluorescent intensity empowers the fabrication of visual stereoscopic fluorescent patterns with excitation dependence, further improving its anti-counterfeiting performance. The obtained fluorescent patterns still show ultrahigh optical properties after being immersed in an acid/base solution (pH 5-12) over one month. In addition, the anti-UV performance of the obtained laser-patterned film with transmittance around 90% is comparable to that of commercial UV-resistant films. This work provided an advanced and feasible approach to fabricating programmable, performance-tunable, subtle fluorescent patterns in large-scale for industrial application.","carbon dots; fluorescent pattern; laser direct writing; surface microstructure; tunable intensity","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Bio-Electronics","","",""
"uuid:b2353f69-def7-43e7-af85-388564926577","http://resolver.tudelft.nl/uuid:b2353f69-def7-43e7-af85-388564926577","A numerical assessment on the managed aquifer recharge to achieve sustainable groundwater development in Chaobai River area, Beijing, China","Liu, S. (TU Delft Water Resources; IHE Delft Institute for Water Education); Zhou, Yangxiao (IHE Delft Institute for Water Education; Hebei University); Luo, Weijia (IHE Delft Institute for Water Education); Wang, Feiran (IHE Delft Institute for Water Education); McClain, M.E. (TU Delft Water Resources; IHE Delft Institute for Water Education); Wang, Xu sheng (China University of Geosciences)","","2022","Intensive groundwater exploitation has depleted groundwater storage and led to a series of geo-environmental problems in Beijing Plain, China. Managed Aquifer Recharge (MAR) has been endorsed to mitigate the groundwater storage depletion and achieve groundwater sustainability. A pilot MAR has been tested in the Chaobai River catchment since 2015. An innovative large-scale MAR consisting of 9 cascade terraced infiltration ponds was proposed and its effectiveness was assessed in this study using an integrated modelling approach. The integrated model coupled the regional and local transient flow and transport processes. The transient regional flow model simulated historical groundwater level declines and storage depletion in the Beijing Plain from 1995 to 2018. The coupled regional and local flow model was used to simulate the pilot MAR test in the Chaobai River from 2015 to 2018. A significant groundwater level increase was observed nearby the pilot MAR since 2015. The transport model results indicate that approximately 40% of the infiltrated water was captured by pumping wells in the No.8 well field. The models were further used to assess the long-term effects of the large-scale MAR from 2020 to 2050. The simulation results show that the groundwater system will reach a new equilibrium state under the implementation of the large-scale MAR scheme. Almost 91% of the abstracted water in the No. 8 well field will come from the MAR infiltration. The proposed large-scale MAR is very effective in restoring the depleted aquifer storage and maintaining the groundwater abstraction in the No.8 well field. However, with the increase of the groundwater level, the infiltration rate of several ponds will decrease. Therefore, it is important to maintain a dynamic balance between artificial recharge and groundwater abstraction in order to achieve a sustainable long-term MAR operation in the region.","Infiltration rate and capacity; Managed aquifer recharge; Restoration of groundwater storage; Simulation models; Sustainability of a large well field","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Water Resources","","",""
"uuid:0a39d7a7-c027-45b3-87c2-731e5770541e","http://resolver.tudelft.nl/uuid:0a39d7a7-c027-45b3-87c2-731e5770541e","Analyzing cell-type-specific dynamics of metabolism in kidney repair","Wang, Gangqi (Leiden University Medical Center); Heijs, Bram (Leiden University Medical Center); Kostidis, Sarantos (Leiden University Medical Center); Mahfouz, A.M.E.T.A. (TU Delft Pattern Recognition and Bioinformatics; Leiden University Medical Center); Rietjens, Rosalie G.J. (Leiden University Medical Center); Bijkerk, Roel (Leiden University Medical Center); Koudijs, Angela (Leiden University Medical Center); van der Pluijm, Loïs A.K. (Leiden University Medical Center); van den Berg, Cathelijne W. (Leiden University Medical Center)","","2022","A common drawback of metabolic analyses of complex biological samples is the inability to consider cell-to-cell heterogeneity in the context of an organ or tissue. To overcome this limitation, we present an advanced high-spatial-resolution metabolomics approach using matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) combined with isotope tracing. This method allows mapping of cell-type-specific dynamic changes in central carbon metabolism in the context of a complex heterogeneous tissue architecture, such as the kidney. Combined with multiplexed immunofluorescence staining, this method can detect metabolic changes and nutrient partitioning in targeted cell types, as demonstrated in a bilateral renal ischemia–reperfusion injury (bIRI) experimental model. Our approach enables us to identify region-specific metabolic perturbations associated with the lesion and throughout recovery, including unexpected metabolic anomalies in cells with an apparently normal phenotype in the recovery phase. These findings may be relevant to an understanding of the homeostatic capacity of the kidney microenvironment. In sum, this method allows us to achieve resolution at the single-cell level in situ and hence to interpret cell-type-specific metabolic dynamics in the context of structure and metabolism of neighboring cells.","","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:db72849c-c043-4cd7-876f-f7fc4a3878ca","http://resolver.tudelft.nl/uuid:db72849c-c043-4cd7-876f-f7fc4a3878ca","Parametric exploration of zero-energy modes in three-terminal InSb-Al nanowire devices","Wang, Ji Yin (Kavli institute of nanoscience Delft); van Loo, N. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Mazur, G.P. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Levajac, V. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Malinowski, F.K. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Lemang, M.F. (TU Delft QN/Afdelingsbureau; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Borsoi, F. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Badawy, G.H.A. (Eindhoven University of Technology); Quintero Perez, M. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; TNO); Heedt, S. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)","","2022","We systematically study three-terminal InSb-Al nanowire devices by using radio-frequency reflectometry. Tunneling spectroscopy measurements on both ends of the hybrid nanowires are performed while systematically varying the chemical potential, magnetic field, and junction transparencies. Identifying the lowest-energy state allows for the construction of the lowest- and zero-energy state diagrams, which show how the states evolve as a function of the aforementioned parameters. Importantly, comparing the diagrams taken for each end of the hybrids enables the identification of states which do not coexist simultaneously, ruling out a significant amount of the parameter space as candidates for a topological phase. Furthermore, altering junction transparencies filters out zero-energy states sensitive to a local gate potential. Such a measurement strategy significantly reduces the time necessary to identify a potential topological phase and minimizes the risk of falsely recognizing trivial bound states as Majorana zero modes.","","en","journal article","","","","","","","","","","","QRD/Kouwenhoven Lab","","",""
"uuid:25778bc8-37e1-4d3c-89db-ee30f1f414da","http://resolver.tudelft.nl/uuid:25778bc8-37e1-4d3c-89db-ee30f1f414da","Risk assessment methods of cascade reservoir dams: a review and reflection","Wang, Te (Zhengzhou University); Li, Zongkun (Zhengzhou University); Ge, W. (TU Delft Safety and Security Science; Zhengzhou University); Zhang, Yadong (Zhengzhou University); Jiao, Yutie (Zhengzhou University); Zhang, Hua (Zhengzhou University); Sun, Heqiang (Zhengzhou University); van Gelder, P.H.A.J.M. (TU Delft Safety and Security Science)","","2022","Risk assessment of cascade reservoir dams is not only the key to ensure the safety of the basin, but also the objective requirement of dam risk management. Based on the development status of cascade reservoirs in China, the complexity of dam risk management of cascade reservoirs compared with a single reservoir was analyzed. By reviewing the advances on the studies of dam risk in cascade reservoirs, this paper summarized their limitations in terms of scientificity and practicability. Moreover, some concepts and methods were proposed on the risk assessment of cascade reservoirs: (1) The dam risk of a cascade reservoir was decomposed into own risk and additional risk, the consequence of its dam breach was decomposed into direct loss and potential loss, and an influence coefficient was defined to reflect the risk transmission and superposition degree among cascade reservoirs; (2) The related concepts and formulas for the calculation of dam risk probability and consequence of cascade reservoirs were proposed, which realized the transition of dam risk assessment method from a single reservoir to cascade reservoirs; (3) A project rank classification method for cascade reservoirs was proposed, which took into account not only the project scale and benefits in socioeconomic development, but also the successive dam breaches possibility and consequences. This study is of great significance to clarify the focus of future research and promote the practical application of dam risk management in cascade reservoirs.","Cascade reservoirs; Dam breach; Probability; Risk assessment; Risk transmission","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Safety and Security Science","","",""
"uuid:e2bbac2c-881a-42d8-8b8b-bafb7924bdeb","http://resolver.tudelft.nl/uuid:e2bbac2c-881a-42d8-8b8b-bafb7924bdeb","Erosion Behavior of Sand-Silt Mixtures: Revisiting the Erosion Threshold","Yao, Peng (Hohai University; Dalian University); Su, Min (Hohai University; Shanghai Estuarine and Coastal Science Research Center); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); van Rijn, Leo C. (LVRS Consultancy); Stive, M.J.F. (TU Delft Coastal Engineering); Xu, Chunyang (Hohai University); Chen, Yongping (Hohai University)","","2022","The erosion threshold, beyond which bed sediments start to move, is a key parameter describing sediment transport processes. For silt-dominated mixtures, in which the grain size is between sand and clay, existing experimental studies exhibit contradictory observations. That is, the erosion was either sand-like or clay-like, suggesting transitional erosion behavior. To explore the underlying mechanism of the transitional erosion behavior of silt-sized sediment, we revisited the topic of the erosion threshold of sand-silt mixtures by carrying out a series of erosion experiments for different bed compositions. The results suggest that there exists a critical silt content of approximately 35%, separating two domains. Below this critical value, the critical bed shear stress follows the Shields criterion, whereas above this value, the erosion threshold of a mixed bed increases abruptly and remains relatively constant with a further increase in silt content. By combining with existing data, we found that the proposed critical silt content acts as a tipping point, beyond which the mixed bed shifts from a sand-dominated to a silt-dominated domain. For the silt-dominated domain, a stable silt skeleton can be formed by attraction forces that resist erosion. However, the attraction forces are too weak to form a stable silt skeleton when the silt content is too small. Based on this finding, a modified critical bed shear stress formula is proposed for silt-dominated mixtures, which results in a better agreement with experimental data (an averaged bias of 10%), performing better than existing formulas (larger than 30%).","critical bed shear stress; erosion threshold; flume experiment; sand-silt mixtures; silt content","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-03-06","","","Coastal Engineering","","",""
"uuid:d86ac5f2-6262-47ce-8f85-ff84d99c99fc","http://resolver.tudelft.nl/uuid:d86ac5f2-6262-47ce-8f85-ff84d99c99fc","Stress topology analysis for porous infill optimization","Wang, Junpeng (Technische Universität München); Wu, J. (TU Delft Materials and Manufacturing); Westermann, Rüdiger (Technische Universität München)","","2022","The optimization of porous infill structures via local volume constraints has become a popular approach in topology optimization. In some design settings, however, the iterative optimization process converges only slowly, or not at all even after several hundreds or thousands of iterations. This leads to regions in which a distinct binary design is difficult to achieve. Interpreting intermediate density values by applying a threshold results in large solid or void regions, leading to sub-optimal structures. We find that this convergence issue relates to the topology of the stress tensor field that is simulated when applying the same external forces on the solid design domain. In particular, low convergence is observed in regions around so-called trisector degenerate points. Based on this observation, we propose an automatic initialization process that prescribes the topological skeleton of the stress field into the density field as solid simulation elements. These elements guide the material deposition around the degenerate points, but can also be remodelled or removed during the optimization. We demonstrate significantly improved convergence rates in a number of use cases with complex stress topologies. The improved convergence is demonstrated for infill optimization under homogeneous as well as spatially varying local volume constraints.","Porous infill; Stress tensor; Topology optimization","en","journal article","","","","","","","","","","","Materials and Manufacturing","","",""
"uuid:611aad1d-1e76-40ed-8d00-9c693bdb6c6f","http://resolver.tudelft.nl/uuid:611aad1d-1e76-40ed-8d00-9c693bdb6c6f","Tomographic SAR imaging with large elevation aperture: a P-band small UAV demonstration","Zeng, Tao (Beijing Institute of Technology; Beijing Institute of Technology Chongqing Innovation Center, Chongqin; Yangtze Delta Region Academy of Beijing Institute of Technology); Liu, Minkun (Beijing Institute of Technology; Beijing Institute of Technology Chongqing Innovation Center, Chongqin); Wang, Yan (Beijing Institute of Technology; Beijing Institute of Technology Chongqing Innovation Center, Chongqin; Yangtze Delta Region Academy of Beijing Institute of Technology); Ding, Zegang (Beijing Institute of Technology; Beijing Institute of Technology Chongqing Innovation Center, Chongqin; Yangtze Delta Region Academy of Beijing Institute of Technology); Li, Linghao (Beijing Institute of Technology; Beijing Institute of Technology Chongqing Innovation Center, Chongqin); Wang, Zhen (Beijing Institute of Technology; Beijing Institute of Technology Chongqing Innovation Center, Chongqin); Wei, Yangkai (Beijing Institute of Technology; Beijing Institute of Technology Chongqing Innovation Center, Chongqin); Wang, J. (TU Delft Microwave Sensing, Signals & Systems)","","2022","Elevation resolution is an important indicator in tomographic SAR imaging as it represents the ability to discriminate closed targets in elevation. In general, the elevation resolution is proportional to the length of the elevation aperture. However, as the elevation aperture increases, the geometric consistency of the image will undesirably deteriorate and hence fails the image coregistration approach required by the traditional super-resolution tomographic imaging. In this paper, a new super-resolution tomographic imaging method is proposed to overcome the inconsistency problem caused by the large elevation aperture. The core strategy is to get rid of two-dimensional image coregistration by applying a three-dimensional (3D) back projection like imaging manner: the 3D space is firstly divided into a 3D imaging grid, each of which is individually imaged via compressive sensing for super-resolution. The effectiveness of the proposed approach is evaluated by both computer simulations and real P-band UAV SAR data.","large elevation aperture; P-band; super-resolution; UAV SAR tomography","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Microwave Sensing, Signals & Systems","","",""
"uuid:5fd7fca6-048d-42c1-a482-479f6134c4d9","http://resolver.tudelft.nl/uuid:5fd7fca6-048d-42c1-a482-479f6134c4d9","Influence of high content crumb rubber and different preparation methods on properties of asphalt under different aging conditions: Chemical properties, rheological properties, and fatigue performance","Wang, Sheng (Tongji University); Huang, Weidong (Tongji University); Liu, X. (TU Delft Pavement Engineering); Lin, P. (TU Delft Pavement Engineering)","","2022","Asphalt pavements are prone to aging in construction and during service, which can affect the properties of the asphalt. The aging behaviors of high content crumb rubber modified asphalt (HCRMA) were investigated in this paper. The binders were aged in the laboratory and the performances before and after aging were tested using the attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) test, temperature sweep (TS) test, frequency sweep tests, multiple stress creep recovery (MSCR) test, zero shear viscosity (ZSV) test, bending beam rheometer (BBR) test, and linear amplitude sweep (LAS) test. The FTIR test result shows that as the aging progresses, the crumb rubber (CR) continues to undergo desulphurization and degradation reactions in the HCRMA, with the release of substances such as silica and S-C bonded material from the CR into the bituminous phase. The elasticity of HCRMA decreases and then increases as the degree of aging increases. Besides, the low temperature performance of HCRMA is controlled by the stiffness value, and the low temperature stress relaxation properties of HCRMA in the aging process are better than that of 20% content crumb rubber modified asphalt. Moreover, aging can reduce the integrity and fatigue resistance of HCRMA while increasing the compatibility of HCRMA.","Aging behaviors; ATR-FTIR; Fatigue resistance; High content crumb rubber modified asphalt; Low temperature performance","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:706d7a44-0294-4cce-ae37-289e92512667","http://resolver.tudelft.nl/uuid:706d7a44-0294-4cce-ae37-289e92512667","Future sediment exchange between the Dutch Wadden Sea and North Sea Coast - Insights based on ASMITA modelling","Lodder, Q.J. (TU Delft Coastal Engineering; Rijkswaterstaat); Huismans, Y. (Deltares); Elias, Edwin (Deltares); de Looff, Harry (Rijkswaterstaat); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2022","The sediment exchange between the Dutch Wadden Sea and the North Sea coastal zone is of key importance to Dutch coastal management. Net sediment import from the coastal zone to the Wadden Sea results in coastal erosion which needs to be compensated through nourishments. At the same time net sediment import is the source of sediment for the intertidal flats in the Wadden Sea to adapt to sea level rise (SLR). Understanding the current and future sediment exchange is therefore essential for sustainable coastal management. Insights in the sediment exchange directly influence the coastal nourishment strategies applied to the Dutch coasts. Projections of the future sediment exchange between the Dutch Wadden Sea and the North Sea are established using the aggregated morphodynamic model ASMITA for five sea level rise scenarios, viz. the present rate of 2 mm/yr and accelerated rates of 4, 6, 8 and 17 mm/yr in 2100. The differences in the projected import rates between the five sea level rise scenarios until 2100 are not as large as the differences in sea level rise rates may suggest. For the Eastern part of the Dutch Wadden Sea, where the morphology is near its dynamic equilibrium, the projected import rate in 2100 varies with a factor 3 (300%), for sea level rise rates from 2 to 17 mm/yr (factor 8.5, 850%). In the western part of the Dutch Wadden Sea, where the morphology is still far from equilibrium due to the closure of the Zuiderzee, the projected import rate in 2100 varies a factor 1.45 (145%) for these sea level rise rates. For the total Dutch Wadden Sea this is a factor 1.7 (170%). The projected increase of the import rate until 2100 with respect to the present situation (2020) is up to a factor 1.45 (145%) for the highest sea level rise scenario, which is significant but not substantial.","ASMITA modelling; Coastal management; Nourishment strategies; Sea level rise; Sediment import; Wadden sea","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:d2ac82ff-aeba-4e4c-b2a6-ba6ecda7e052","http://resolver.tudelft.nl/uuid:d2ac82ff-aeba-4e4c-b2a6-ba6ecda7e052","A stabilized mixed-FE scheme for frictional contact and shear failure analyses in deformable fractured media","Wang, L. (TU Delft Numerical Analysis); Vuik, Cornelis (TU Delft Delft Institute of Applied Mathematics); Hajibeygi, H. (TU Delft Reservoir Engineering)","","2022","Simulation of fracture contact mechanics in deformable fractured media is of paramount important in computational mechanics. Previous studies have revealed that compressive loading may produce mode II fractures, which is quite different from mode I fractures induced by tensile loading. Furthermore, fractures can cross each other. This will increase the complexity of their network deformation under different loading types significantly. In this work, a stabilized mixed-finite element (FE) scheme with Lagrange multipliers is proposed in the framework of variational formulation, which is able to simulate frictional contact, shear failure (mode II) and opening (mode I) of multiple crossing fractures. A novel treatment is devised to guarantee physical solutions at the intersection of crossing fractures. A preconditioner is introduced to re-scale the saddle-point algebraic system and to preserve the numerical robustness. Then, a solution strategy is designed to calculate the unknowns, displacement and Lagrange multipliers, in one algebraic system. Later, numerical tests are conducted to study mechanical behaviors of fractured media. Benchmark study is performed to verify the presented mixed-FE scheme. A deformable medium with crossing fractures is simulated under mixed-mode loading types. The characteristics of fracture contact, surface sliding, opening and variation of stress intensity factor are analyzed. Simulation results show that the curve of slippage induced by compression, as well as the opening induced by internal fluid pressure, along the fracture length holds a parabolic shape. The diagonal contact point, at the intersecting position of the crossing fractures, is studied in detail, specially under different stress states. Finally, the impact of intersecting fractures on frictional contact mechanics is investigated for different loading conditions.","Crossing fractures; Fractured media; Frictional contact; Lagrange multipliers; Mixed-finite element method","en","journal article","","","","","","","","","","","Numerical Analysis","","",""
"uuid:4d977959-be7d-402f-b2ec-776883aca05e","http://resolver.tudelft.nl/uuid:4d977959-be7d-402f-b2ec-776883aca05e","Study on green extraction of limonene from orange peel and cascade catalysis to produce carvol and carvone in deep eutectic solvents","Li, Zongquan (South China University of Technology); Ma, Yunjian (South China University of Technology; Macau University of Science and Technology); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Yonghua (South China University of Technology; Guangdong Youmei Institute of Intelligent Bio-manufacturing Co, Foshan)","","2022","Carvol and carvone are oxidation products from the natural product limonene. They are important raw materials for the flavours and fragrances industry and also act as pharmaceutical active ingredients. Orange waste peels possibly represent an attractive source for limonene, but studies on valorizing orange peel wastes are rare. In this study, we report a new enzymatic cascade system for the in-situ conversion of limonene from orange peel into valued-added carvol and carvone. The use of deep eutectic solvents (DES) allows for efficient in-situ extraction of limonene from waste orange peels. We propose a dual function use of DES as solvent for the extraction and the biocatalytic oxidation of limonene as well as cosubstrate to promote the oxidation reaction. Using ChCl-Pro-H2O DES for the extraction of limonene from waste orange peels, approximately 17 milligrams of limonene per gram of orange peel was achieved at 40°C for 24 h. Then, with ChCl-Pro-H2O DES as the extractant and reaction medium, a cascade reaction system of choline oxidase (ChOx) and unspecific peroxygenase (UPO) was established to catalyse the conversion of limonene into carvol and carvone. The concentration of the final products was up to about 1.6 mmol L−1. This study showed a biocatalytic transformation pathway and provides technical support for the high-value utilization of waste in orange peel.","Carvol; carvone; Cascade reaction; deep eutectic solvents; Orange peel waste","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-11-09","","","BT/Biocatalysis","","",""
"uuid:198ac2a6-1596-4330-b474-8fcdc8bac9fb","http://resolver.tudelft.nl/uuid:198ac2a6-1596-4330-b474-8fcdc8bac9fb","Tuning homogenization of high-strength aluminum alloys through thermodynamic alloying approach","Wang, Yawen (University of Science and Technology Beijing; CRRC, Beijing); Hou, Longgang (University of Science and Technology Beijing; Brunel University London; Nanjing Institute for Advanced Transportation Equipment and Technology, Nanjing); Su, Hui (University of Science and Technology Beijing); Tian, Qingkun (University of Science and Technology Beijing); Yu, Kangcai (University of Science and Technology Beijing; Chinalco Materials Application Research Institution Co., Beijing); Eskin, Dmitry (Brunel University London; National Research Tomsk State University); Katgerman, L. (TU Delft Team Kevin Rossi; Katgerman Aluminium Technology); Zhuang, Linzhong (University of Science and Technology Beijing)","","2022","The alloy design and homogenization processes are intimately associated with the microstructure, phase composition and performance for Al-Zn-Mg-Cu alloys. The microstructures and phase composition of a series of Al-Zn-Mg-Cu alloys before and after the homogenization treatments were investigated along with thermodynamic calculation to understand the underlying relationship. The eutectic microstructures (α-Al + M (Mg(ZnAlCu)2)) are dominating with Cu-enriched [AlCuMgZn] particles, both depending on the Zn:Mg ratio and (Cu + Mg) content, in addition to minor constituent θ (Al2Cu) and Al7Cu2Fe phases in the as-cast alloys. The optimal homogenization process was suggested based on the analysis of the residual phases (i.e., the S (Al2CuMg) phase) since all (for low/mediate-(Cu + Mg) alloys) or partially (for high-(Cu + Mg) alloys (∼>4.24 wt%)) S (Al2CuMg) particles were dissolved during the homogenization. This residual S phase may be transformed from the primary M and/or Cu-enriched [AlCuMgZn] phases. The homogenization kinetics calculation results agreed well with above experimental results. A critical (Cu + Mg) level and a linear correlation between Cu and Mg concentrations were revealed based on the thermodynamically modelling, which can be conductive to determine the optimal homogenization process. Furthermore, the solubility limit and stoichiometric balance principles based on controlling the homogenized microstructures can guide the composition design for advanced high-strength aluminum alloys.","Aluminum alloys; Composition; Homogenization; Microstructure; Thermodynamic calculation","en","journal article","","","","","","","","","","","Team Kevin Rossi","","",""
"uuid:94c31f1b-9472-4a89-a295-d5060c26d75c","http://resolver.tudelft.nl/uuid:94c31f1b-9472-4a89-a295-d5060c26d75c","Extraction of low molecular weight polyhydroxyalkanoates from mixed microbial cultures using bio-based solvents","Elhami, Vahideh (University of Twente); van de Beek, Noor (University of Twente); Wang, Liangshin (Student TU Delft); Picken, S.J. (TU Delft ChemE/Advanced Soft Matter); Tamis, J. (Paques B.V.); Sousa, João A.B. (Paques B.V.); Hempenius, Mark A. (University of Twente); Schuur, Boelo (University of Twente)","","2022","(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) obtained from waste/wastewater using a mixed microbial culture (MMC) usually varies in its properties due to daily variation in the waste/wastewater composition applied as feedstock. In the current study, the average molecular weight (MW) of PHBV was purposely reduced from about 1 MDa to about 200 kDa by drying the PHBV-rich biomass at elevated temperature of 120 °C for 18 h to ease extraction and handling. Furthermore, conversion into value-added chemicals such as trans-crotonic acid (trans-CA) and trans-2-pentenoic acid (2-PA) by thermal decomposition (pyrolysis) benefits from the lower MW. For the extraction of low MW PHBV, the use of the bio-based solvents 2-methyltetrahydroxyfuran (2-MTHF) and dihydrolevoglucosenone (cyrene) was studied. The maximum extraction yield of 62 ± 3 % with purity of > 99 % was achieved with 2-MTHF at 80 °C for an hour with high biomass to solvent ratio of 5 % (g/mL). Cyrene-based extractions resulted in the highest yield of 57 ± 2 % with purity of > 99 % at 120 °C in 2 h with 5 % (g/mL) biomass to solvent ratio. The mass balance closure over the extraction process indicated that about 15 % and 10 % of polymer has remained in the residual biomass after extraction by 2-MTHF and cyrene, respectively. The performance of these new solvents to extract polymers with various average MW was compared to the benchmark extractions using chloroform and dimethyl carbonate (DMC). It was found that for the polymers with low average MW the extraction efficiency of the proposed solvents exceeds the benchmark solvents.","2-Methyltetrahydroxyfuran (2-MTHF); Cyrene; Molecular weight (MW); Poly(3-hydroxybutyrate-co-3-hydroxyvalerate); Solvent extraction; Wastewater","en","journal article","","","","","","","","","","","ChemE/Advanced Soft Matter","","",""
"uuid:d0be1bbc-2a43-4b2f-9db8-cd05a1a1e8a3","http://resolver.tudelft.nl/uuid:d0be1bbc-2a43-4b2f-9db8-cd05a1a1e8a3","On the magnetic nanoparticle injection strategy for hyperthermia treatment","Jiang, Qian (The Hong Kong Polytechnic University); Ren, Feng (The Hong Kong Polytechnic University; Northwestern Polytechnical University); Wang, Chenglei (The Hong Kong Polytechnic University); Wang, Zhaokun (The Hong Kong Polytechnic University); Kefayati, Gholamreza (University of Tasmania); Kenjeres, S. (TU Delft ChemE/Transport Phenomena); Vafai, Kambiz (University of California); Liu, Yang (The Hong Kong Polytechnic University); Tang, Hui (The Hong Kong Polytechnic University)","","2022","We developed a dedicated computational framework by coupling the lattice-Boltzmann-method (LBM) modeling and the particle-swarm-optimization (PSO) algorithm to search optimal strategies of magnetic nanoparticle (MNP) injection for hyperthermia-based cancer treatment. Two simplified tumor models were considered: a circular model representing geometrically regular tumors and an elliptic model representing geometrically irregular tumors, both sharing the same area. The temperature distribution in the tumor and its surrounding healthy tissue was predicted by solving the Pennes’ bio-heat transfer equation (PBHTE). Both single- and multi-site injection strategies were explored. The results suggest that the multi-site injection strategies generally work well, while the single-site injection strategy fails even on the simplest circular tumor model. The more the injection sites, the better the performance. In particular, when the number of injection sites reaches eight, all temperature requirements can be nearly 100% satisfied in both tumor models. Whether or not including the minimum dose requirement in the objective function only affects the optimization results by less than 2%. The thermal dose was also assessed by considering both temperature and heat exposure time. It was found that the optimal multi-site injection strategies perform reasonably well for both tumor models. Although the setting is only two dimensional and the optimization is on very simplified tumor models, the framework adopted in this present study works well and can provide useful insights into magnetic hyperthermia treatment.","Lattice Boltzmann method; Magnetic hyperthermia treatment; Magnetic nanoparticle; Particle swarm optimization","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","ChemE/Transport Phenomena","","",""
"uuid:56123a69-f352-4f48-8c08-c05ea600c285","http://resolver.tudelft.nl/uuid:56123a69-f352-4f48-8c08-c05ea600c285","A designed wall roughness approach to improve turbulent heat transfer to supercritical CO2 flowing in horizontal tubes","Wang, Jianyong (Sun Yat-sen University); Yang, Jun (Sun Yat-sen University); Gong, Jishuang (Sun Yat-sen University); Zhao, Chunrong (University of Sydney); Hooman, K. (TU Delft Process and Energy)","","2022","Supercritical flow through a horizontal pipe leads to a non-uniform peripheral wall temperature distribution even when the wall heat flux is kept constant and uniform. This is attributed to lower heat transfer coefficient at the top section where the denser fluid tends to sink. Hence, to obtain a uniform wall temperature, a designed wall roughness is devised. Uniform sand-grain roughness is employed to only partly cover the top half of the pipe wall. Numerical simulations were conducted using the SST k−ω turbulence model. The simulation results indicate that our proposed design can lead to a more uniform heat transfer distribution over the wall periphery compared with the smooth pipe. An extreme case was also considered where the inner wall was completely covered with roughness elements. While heat transfer augmentation was observed for this case, the excess pressure drop was prohibitively higher compared with a pipe with designed wall roughness.","Horizontal pipe; Partly; Sand-grain roughness; Supercritical flow; Uniform heat transfer","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-03-08","","Process and Energy","","","",""
"uuid:72f466e7-d420-4d22-93bb-fb3f6562b434","http://resolver.tudelft.nl/uuid:72f466e7-d420-4d22-93bb-fb3f6562b434","2D Dion–Jacobson CsPbI3 with Enhanced Interlayer Coupling for Stable and Efficient Photovoltaics","Lei, Yutian (Lanzhou University); Peng, Guoqiang (Lanzhou University); Wang, H. (TU Delft Photovoltaic Materials and Devices); Wang, Gang (Ningbo University); Yang, Siwei (Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences); Wang, Qian (School of Physical Science and Technology; Lanzhou University); Li, Zhen Hua (Lanzhou University); Jin, Zhiwen (Lanzhou University)","","2022","Inorganic 2D layered CsPbI3 is awaiting to overcome the phase instability of traditional 3D components. However, the most reported Ruddlesden–Popper (RP) phase 2D CsPbI3 leads to larger interlayer distance and weaker interlayer coupling since the existence of the van der Waals gap, which deteriorates the performance of the device and makes the improvement of stability unsatisfactory. Herein, this work resorts ethylenediamine cations (EDA2+) to construct a series of Dion–Jacobson (DJ) phase 2D CsPbI3 as (EDA)Csn−1PbnI3n+1 with van der Waals gap eliminated. Combining simulation calculations and experiments, it is found that the (EDA)Csn−1PbnI3n+1 has enhanced intermolecular forces to overcome the problem of insufficient crystallization power caused by large steric hindrance in the film assembly process compared to phenethylammonium-based RP phase analogues. In addition, profit from the reduced interlayer distance and stronger coupling, the rigidity of the structure is increased, and the annoying non-radiative recombination caused by structural fluctuations is alleviated. As a result, the 2D layered DJ phase CsPbI3-based solar cells deliver eminent performance than RP phase analogues, especially the 2D (EDA)(Cs)4Pb5I16 (n = 5) device exhibits a record PCE of 10.43% in this work, and significantly enhanced stability.","2D inorganic perovskite; Dion–Jacobson; efficiency and stability; layer coupling; Ruddlesden–Popper","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-03-27","","","Photovoltaic Materials and Devices","","",""
"uuid:3784d02c-1143-4f5c-b2de-7fdcb99c01af","http://resolver.tudelft.nl/uuid:3784d02c-1143-4f5c-b2de-7fdcb99c01af","Warranty Reserve Management: Demand Learning and Funds Pooling","Wang, Xiao Lin (Business School of Sichuan University); Zhong, Yuanguang (South China University of Technology); Li, L. (TU Delft Air Transport & Operations); Xie, Wei (South China University of Technology); Ye, Zhi Sheng (National University of Singapore)","","2022","Problem definition: Warranty reserves are funds used to fulfill future warranty obligations for a product. In this paper, we investigate the warranty reserve planning problem faced by a manufacturing firm who manages warranties for multiple products. Academic/practical relevance: It is nontrivial to determine a proper amount of reserves to hold, because warranty expenditures are random in nature and reserving either excess or insufficient cash would incur losses. How can warranty reserve levels be optimized and promptly adjusted is a focal issue, especially for firms selling multiple products. Methodology: Inspired by the general pattern of empirical warranty claims data, we first develop an aggregate warranty cost (AWC) forecasting model for a single product by coupling stochastic product sales and failure processes, which can be used to plan for warranty reserves periodically. The reserve levels are then optimized via a distributionally robust approach, because the exact distribution of AWC is generally unknown. To reduce the losses generated from managing the funds, we further investigate two potential loss-reduction approaches: demand learning and funds pooling. Results: For the demand learning algorithm, we prove that, as the sales period grows, the optimal learning parameter asymptotically converges to a constant in a fairly fast rate; our simulation experiments show that the performance of demand learning is promising and robust under general warranty claim patterns. Moreover, we find that the benefits of funds pooling change over different stages of the warranty life cycle; in particular, the relative pooling benefit in terms of reserve losses is nonincreasing over time. Managerial implications: This study offers guidelines on how manufacturers should adaptively forecast and dynamically plan warranty reserves over the warranty life cycle.","adaptive learning; distribution free; newsvendor; reserve management; risk pooling","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Air Transport & Operations","","",""
"uuid:8f0e69d7-9912-42dc-a59f-4773816c3a30","http://resolver.tudelft.nl/uuid:8f0e69d7-9912-42dc-a59f-4773816c3a30","Accurate modeling and simulation of seepage in 3D heterogeneous fractured porous media with complex structures","Wang, L. (TU Delft Numerical Analysis; GeoRessources Lab); Wang, Y. (TU Delft Numerical Analysis); Vuik, Cornelis (TU Delft Delft Institute of Applied Mathematics); Hajibeygi, H. (TU Delft Reservoir Engineering)","","2022","The past decades have witnessed an increasing interest in numerical simulation for flow in fractured porous media. To date, most studies have focused on 2D or pseudo-3D computational models, where the impact of 3D complex structures on seepage has not been fully addressed. This work presents a method for modeling seepage in 3D heterogeneous porous media. The complex structures, typically the stochastic discrete fractures and inclusions, are able to be simulated. A mesh strategy is proposed to discretize the complex domain. In particular, a treatment on the intersected elements is developed to ensure a conforming mesh. Then, numerical discretization is provided, in which the flux interactions of fractures, inclusions and surrounding rock matrix are included. Numerical tests are performed to analyze the hydraulic characteristics of 3D fractured media. First, the developed framework is validated by comparing numerical solutions with the results of embedded discrete fracture model. Next, the effects of orientation, aperture and radius of fractures on fluid flow and equivalent permeability tensor are analyzed. The variations of pressure distribution are studied in heterogeneous and homogeneous media. Finally, the hydraulic properties of a medium with complex structures are investigated to show the difference of hydraulic feature between fractures and inclusions.","Discrete fractures; Fractured porous media; Heterogeneity; Inclusions; Seepage; Three-dimensional modeling","en","journal article","","","","","","","","","","","Numerical Analysis","","",""
"uuid:f1b54fb6-6bea-4e94-8d4b-f18f342bc206","http://resolver.tudelft.nl/uuid:f1b54fb6-6bea-4e94-8d4b-f18f342bc206","Improving Li-ion interfacial transport in hybrid solid electrolytes","Liu, M. (TU Delft RST/Storage of Electrochemical Energy); Zhang, S. (TU Delft RST/Storage of Electrochemical Energy); van Eck, Ernst R.H. (Radboud Universiteit Nijmegen); Wang, C. (TU Delft RST/Storage of Electrochemical Energy); Ganapathy, S. (TU Delft RID/TS/Instrumenten groep); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2022","The development of commercial solid-state batteries has to date been hindered by the individual limitations of inorganic and organic solid electrolytes, motivating hybrid concepts. However, the room-temperature conductivity of hybrid solid electrolytes is still insufficient to support the required battery performance. A key challenge is to assess the Li-ion transport over the inorganic and organic interfaces and relate this to surface chemistry. Here we study the interphase structure and the Li-ion transport across the interface of hybrid solid electrolytes using solid-state nuclear magnetic resonance spectroscopy. In a hybrid solid polyethylene oxide polymer–inorganic electrolyte, we introduce two representative types of ionic liquid that have different miscibilities with the polymer. The poorly miscible ionic liquid wets the polymer–inorganic interface and increases the local polarizability. This lowers the diffusional barrier, resulting in an overall room-temperature conductivity of 2.47 × 10−4 S cm−1. A critical current density of 0.25 mA cm−2 versus a Li-metal anode shows improved stability, allowing cycling of a LiFePO4–Li-metal solid-state cell at room temperature with a Coulombic efficiency of 99.9%. Tailoring the local interface environment between the inorganic and organic solid electrolyte components in hybrid solid electrolytes seems to be a viable route towards designing highly conducting hybrid solid electrolytes.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","RST/Storage of Electrochemical Energy","","",""
"uuid:3d281114-aea5-43ce-8389-b5f4ddb21fe4","http://resolver.tudelft.nl/uuid:3d281114-aea5-43ce-8389-b5f4ddb21fe4","Effectiveness of trip planner data in predicting short-term bus ridership","Wang, Z. (TU Delft Transport and Planning); Pel, A.J. (TU Delft Transport and Planning); Verma, T. (TU Delft Policy Analysis); Krishnakumari, P.K. (TU Delft Transport and Planning); van Brakel, Peter (REISinformatiegroep); van Oort, N. (TU Delft Transport and Planning)","","2022","Predictions on Public Transport (PT) ridership are beneficial as they allow for sufficient and cost-efficient deployment of vehicles. On an operational level, this relates to short-term predictions with lead times of less than an hour. Where conventional data sources on ridership, such as Automatic Fare Collection (AFC) data, may have longer lag times and contain no travel intentions, in contrast, trip planner data are often available in (near) real-time and are used before traveling. In this paper, we investigate how such data from a trip planner app can be utilized for short-term bus ridership predictions. This is combined with AFC data (in this case smart card data) to construct a ground truth on actual ridership. Using informative variables from the trip planner dataset through correlation analysis, we develop 3 supervised Machine Learning (ML) models, including k-nearest neighbors, random forest, and gradient boosting. The best-performing model relies on random forest regression with trip planner requests. Compared with the baseline model that depends on the weekly trend, it reduces the mean absolute error by approximately half. Moreover, using the same model with and without trip planner data, we prove the usefulness of trip planner data by an improved mean absolute error of 8.9% and 21.7% and an increased coefficient of determination from a 5-fold cross-validation of 7.8% and 18.5% for two case study lines, respectively. Lastly, we show that this model performance is maintained even for the trip planner requests with prediction lead times up to 30 min ahead, and for different periods of the day. We expect our methodology to be useful for PT operators to elevate their daily operations and level of service as well as for trip planner companies to facilitate passenger replanning, in particular during peak hours.","Bus ridership prediction; Machine learning; Public transport; Trip planner","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:83fcd7b1-52e2-4256-af2c-98ab1c55df08","http://resolver.tudelft.nl/uuid:83fcd7b1-52e2-4256-af2c-98ab1c55df08","Modeling the competition between multiple Automated Mobility on-Demand operators: An agent-based approach","Wang, S. (TU Delft Mathematical Physics); Correia, Gonçalo (TU Delft Transport and Planning); Lin, H.X. (TU Delft Mathematical Physics; Universiteit Leiden)","","2022","Automated Mobility-on-Demand (AMoD) systems, in which fleets of automated vehicles provide on-demand services, are expected to transform urban mobility systems. Motivated by the rapid development of AMoD services delivered by self-driving car companies, an agent-based model (ABM) has been developed to study the coexistence phenomena of multiple AMoD operators competing for customers. The ABM is used to investigate how changes in pricing strategies, assignment methods, and fleet sizes affect travelers’ choice of different AMoD services and the operating performance of competing operators in the case-study city of The Hague, in the Netherlands. Findings suggest that an optimal assignment algorithm can reduce the average waiting time by up to 24% compared to a simple heuristic algorithm. We also find that a larger fleet could increase demand but lead to higher waiting times for its users and higher travel times for competing operators’ users due to the added congestion. Notably, pricing strategies can significantly affect travelers’ choice of AMoD services, but the effect depends strongly on the time of the day. Low-priced AMoD services can provide high service levels and effectively attract more demand, with up to 64.7% of customers choosing the very early morning service [5:30 AM,7:20 AM]. In the subsequent morning hours, high-priced AMoD services are more competitive in attracting customers as more idle vehicles are available. Based on the quantitative analysis, policies are recommended for the government and service operators.","Agent-based modeling; Automated vehicles; Emerging urban mobility; Future scenarios; Multinomial logit; Operating strategies","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:520c1006-fadc-4dff-80be-dd21687b7bba","http://resolver.tudelft.nl/uuid:520c1006-fadc-4dff-80be-dd21687b7bba","Introducing a comprehensive physics-based modelling framework for tandem and other PV systems","Vogt, M.R. (TU Delft Photovoltaic Materials and Devices); Ruiz Tobon, C.M. (TU Delft Photovoltaic Materials and Devices); Alcañiz Moya, A. (TU Delft Photovoltaic Materials and Devices); Procel Moya, P.A. (TU Delft Photovoltaic Materials and Devices); Blom, Y. (TU Delft Photovoltaic Materials and Devices); Nour El Din, A. (TU Delft Energie and Industrie); Stark, T. (Student TU Delft); Wang, Z. (Student TU Delft); Goma, E. Garcia (Student TU Delft); Etxebarria, J. G. (Student TU Delft); Ziar, H. (TU Delft Photovoltaic Materials and Devices); Zeman, M. (TU Delft Electrical Sustainable Energy); Santbergen, R. (TU Delft Photovoltaic Materials and Devices); Isabella, O. (TU Delft Photovoltaic Materials and Devices)","","2022","We introduce a novel simulation tool capable of calculating the energy yield of a PV system based on its fundamental material properties and using self-consistent models. Thus, our simulation model can operate without measurements of a PV device. It combines wave and ray optics and a dedicated semiconductor simulation to model the optoelectronic PV device properties resulting in the IV-curve. The system surroundings are described via spectrally resolved ray tracing resulting in a cell resolved irradiance distribution, and via the fluid dynamics-based thermal model, in the individual cell temperatures. A lumped-element model is used to calculate the IV-curves of each solar cell for every hour of the year. These are combined factoring in the interconnection to obtain the PV module IV-curves, which connect to the inverter for calculating the AC energy yield. In our case study, we compare two types of 2 terminal perovskite/silicon tandem modules with STC PV module efficiencies of 27.7% and 28.6% with a reference c-Si module with STC PV module efficiency of 20.9%. In four different climates, we show that tandem PV modules operate at 1–1.9 °C lower yearly irradiance weighted average temperatures compared to c-Si. We find that the effect of current mismatch is significantly overestimated in pure optical studies, as they do not account for fill factor gains. The specific yields in kWh/kWp of the tandem PV systems are between −2.7% and +0.4% compared to the reference c-Si system in all four simulated climates. Thus, we find that the lab performance of the simulated tandem PV system translates from the laboratory to outdoors comparable to c-Si systems.","Energy yield modelling; Operating temperature; Opto-electric device simulation; Pervoskite/silicon tandem; Specific yield; Tandem PV systems","en","journal article","","","","","","","","","","Electrical Sustainable Energy","Photovoltaic Materials and Devices","","",""
"uuid:f59eb904-bdb1-4a59-920b-35d058a6ef18","http://resolver.tudelft.nl/uuid:f59eb904-bdb1-4a59-920b-35d058a6ef18","Solvent Engineering for High-Performance Two-Dimensional Ruddlesden-Popper CsPbI3Solar Cells","Chen, Haiqiang (Lanzhou University); Lei, Yutian (Lanzhou University); Yao, Huanhuan (Lanzhou University); Li, Zhizai (Lanzhou University); Peng, Guoqiang (Lanzhou University); Zhou, Xufeng (Liaocheng University); Wang, H. (TU Delft Photovoltaic Materials and Devices); Wang, Qian (Lanzhou University); Jin, Zhiwen (Lanzhou University)","","2022","Two-dimensional (2D) Ruddlesden-Popper (RP) CsPbI3 exhibits enhanced phase stability compared with 3D CsPbI3. However, the issue of the uncontrollable crystallization process limits its photovoltaic performance. Here, the influence of a binary mixed solvent on the film quality and photovoltaic properties of (PEA)2Cs4Pb5I16 (n = 5) is studied in detail. It is demonstrated that the crystallization rate and crystal growth can be controlled by adjusting the amount of dimethyl sulfoxide (DMSO). Optimizing the solvent composition with adding 10% DMSO in pure dimethyl formamide (DMF) leads to perfect coverage, larger flaky 2D grains, reduced grain boundaries, and a better vertical orientation to the substrate due to the formation of a more stable intermediate phase. This can form good interface contact, which is beneficial to charge transport/extraction between TiO2 (electron transport layer, ETL) and perovskite, finally resulting in improved device performance. The enhancement of the power conversion efficiency of the optimized device based on DMF/DMSO (9:1) is 3.57% compared with the reference device based on pure DMF. This work illustrates the role of crystallization kinetics in the RP CsPbI3 film and offers a simple and effective method for high-performance 2D CsPbI3 solar cells.","2D inorganic perovskites; crystallization kinetics; intermediate phase; Ruddlesden-Popper phase; solvent engineering","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-02-19","","","Photovoltaic Materials and Devices","","",""
"uuid:0ed74d6c-6c05-4c3f-95c5-5c08b20e3fb9","http://resolver.tudelft.nl/uuid:0ed74d6c-6c05-4c3f-95c5-5c08b20e3fb9","Radio-Frequency C - V Measurements with Subattofarad Sensitivity","Malinowski, F.K. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Han, L. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); de Jong, D. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, Ji Yin (Kavli institute of nanoscience Delft; Student TU Delft); Prosko, C.G. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre); Krogstrup, Peter (University of Copenhagen); Bakkers, Erik P.A.M. (Eindhoven University of Technology); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Koski, Jonne V. (Microsoft Quantum Lab Delft)","","2022","We demonstrate the use of radio-frequency (rf) resonators to measure the capacitance of nanoscale semiconducting devices in field-effect transistor configurations. The rf resonator is attached to the gate or the lead of the device. Consequently, tuning the carrier density in the conducting channel of the device affects the resonance frequency, quantitatively reflecting its capacitance. We test the measurement method on InSb and InAs nanowires at dilution-refrigerator temperatures. The measured capacitances are consistent with those inferred from the periodicity of the Coulomb blockade of quantum dots realized in the same devices. In an implementation of the resonator using an off-chip superconducting spiral inductor we find the measurement sensitivity values reaching down to 75zF/Hz at 1 kHz measurement bandwidth, and noise down to 0.45 aF at 1 Hz bandwidth. We estimate the sensitivity of the method for a number of other implementations. In particular, we predict a typical sensitivity of about 40zF/Hz at room temperature with a resonator composed of off-the-shelf components. Of several proposed applications, we demonstrate two: the capacitance measurement of several identical 80-nm-wide gates with a single resonator, and the field-effect mobility measurement of an individual nanowire with the gate capacitance measured in situ.","","en","journal article","","","","","","","","","","","QRD/Kouwenhoven Lab","","",""
"uuid:80b324be-727f-4831-8a5e-6a93014fc4f0","http://resolver.tudelft.nl/uuid:80b324be-727f-4831-8a5e-6a93014fc4f0","A Bienzymatic Cascade for the Complete Hydrolysis of Phthalic Acid Esters","Yang, Liu (South China University of Technology); Ma, Yunjian (South China University of Technology; Macau University of Science and Technology); Chen, Yebao (South China University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Yonghua (GuangdongYoumeiInstituteof IntelligentBio-manufacturing, Guangdong)","","2022","Phthalic acid esters (PAEs) are widely used as plastic additives to increase the flexibility and durability of plastics. Constantly leaching out from plastics, PAEs are ubiquitously found in the environment. As PAEs exhibit biological activities such as being endocrine disruptive, the quest for efficient degradation strategies continues. Here, we report a bienzymatic degradation system for PAEs to phthalic acid (PA) using a cascade comprising two hydrolases, EstJ6 and P8219. The reaction conditions were optimized with respect to concentrations of both enzymes, temperature, and initial pH. Finally, the substrate scope of the new cascade was investigated, revealing that particularly PAEs with relatively small alcohols were degraded to more than 90 %. This present study provides a potential doable biocatalytic strategy for the complete hydrolysis of PAEs.","cascade; degradation; hydrolase; phthalic acid; phthalic acid esters","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-02-10","","","BT/Biocatalysis","","",""
"uuid:efbca5b3-433a-4171-9d5a-377aa59a0c18","http://resolver.tudelft.nl/uuid:efbca5b3-433a-4171-9d5a-377aa59a0c18","Nonlocal measurement of quasiparticle charge and energy relaxation in proximitized semiconductor nanowires using quantum dots","Wang, Guanzhong (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Dvir, T. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); van Loo, N. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Mazur, G.P. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Gazibegovic, Sasa (Eindhoven University of Technology); Badawy, G.H.A. (Eindhoven University of Technology); Bakkers, Erik P.A.M. (Eindhoven University of Technology); Kouwenhoven, Leo P. (Microsoft Quantum Lab Delft); de Lange, G. (Microsoft Quantum Lab Delft)","","2022","The lowest-energy excitations of superconductors do not carry an electric charge, as their wave function is equally electron-like and hole-like. This fundamental property is not easy to study in electrical measurements that rely on the charge to generate an observable signal. The ability of a quantum dot to act as a charge filter enables us to solve this problem and measure the quasiparticle charge in superconducting-semiconducting hybrid nanowire heterostructures. We report measurements on a three-terminal circuit, in which an injection lead excites a nonequilibrium quasiparticle distribution in the hybrid system, and the electron or hole component of the resulting quasiparticles is detected using a quantum dot as a tunable charge and energy filter. The results verify the chargeless nature of the quasiparticles at the gap edge and reveal the complete relaxation of injected charge and energy in a proximitized nanowire, resolving open questions in previous three-terminal experiments.","","en","journal article","","","","","","","","","","","QRD/Kouwenhoven Lab","","",""
"uuid:7788c228-d0d5-44cb-853d-fd00158109d9","http://resolver.tudelft.nl/uuid:7788c228-d0d5-44cb-853d-fd00158109d9","Plot-level reconstruction of 3D tree models for aboveground biomass estimation","Fan, Guangpeng (Beijing Forestry University; Beijing Key Laboratory of Urban Spatial Information Engineering); Xu, Zhenyu (Beijing Forestry University); Wang, Jinhu (Chinese Academy of Sciences); Nan, L. (TU Delft Urban Data Science); Xiao, Huijie (Beijing Forestry University); Xin, Zhiming (Chinese Academy of Forestry); Chen, Feixiang (Beijing Forestry University)","","2022","Complexity of forest structure is an important factor contributing to uncertainty in aboveground biomass estimates. In this study, we present a new method for reducing uncertainty in forest aboveground biomass (AGB) estimation based on plot-level terrestrial laser scanner (TLS) point clouds reconstruction. The method estimates the total AGB of plots with complex structures after automatically performing the steps of ground point filtering, single tree segmentation, and three-dimensional (3D) structure reconstruction. We used plot data from temperate and tropical forest ecosystems to verify the effectiveness of the method, reconstructing a 1300 m2 temperate plantation plot and a 5000 m2 mingled forest plot, respectively. The total biomass of 153 trees in the plantation plot was overestimated by 17.12 %, and the total biomass of 61 trees in the mingled forest plot was underestimated by 10.88 %. We found that the uncertainty of aboveground biomass estimation in tropical forests with more complex structures is not necessarily greater than in plantations. Therefore, in large-scale remote sensing observations of forest biomass, the number or area of plots can be increased to reduce the uncertainty of the results caused by the complex structure. The focus of this study is to explore TLS point clouds modeling methods to reduce the uncertainty in AGB estimation caused by the complexity of forest structures, and to provide reference cases for plot-level point clouds reconstruction methods. Forest ecologists can use this method to regularly observe forest growth and obtain indicators related to forest ecology without destroying trees.","Above-ground biomass; Complex forest structure; Estimation uncertainty; Plot-level; TLS point clouds","en","journal article","","","","","","","","","","","Urban Data Science","","",""
"uuid:7311fb79-4215-43be-9c36-0d3e4aebfba9","http://resolver.tudelft.nl/uuid:7311fb79-4215-43be-9c36-0d3e4aebfba9","Railway ballast layer inspection with different GPR antennas and frequencies","Liu, Guixian (China Academy of Railway Sciences); Peng, Zhan (China Academy of Railway Sciences); Jing, Guoqing (Beijing Jiaotong University); Wang, Shilei (China Academy of Railway Sciences); Li, Yaonan (China Academy of Railway Sciences); Guo, Y. (TU Delft Railway Engineering)","","2022","Ground penetrating radar (GPR) is a popular technology for inspecting railway ballast layer, mainly on the ballast fouling level. However, different GPR antennas with different frequencies are suitable for different inspection emphasis and diverse railway lines (weather and sub-structure). In addition, the full-scale track model (with subgrade) for experimental tests was not seen in earlier studies. For further application of GPR in China, the GPR inspections (with 400 MHz, 900 MHz and 2 GHz antennas) were performed on a 30 m long full-scale track and three railway lines (different weather and sub-structure). Results show that ballast layer inspection should be performed mainly with the 2 GHz antenna and supplemented by the 400 MHz and 900 MHz antennas. The weather has great influence on the results of GPR inspection. This study is helpful for supplementing the guidance of ballast layer inspection with GPR.","Ballast fouling; GPR; Ground penetrating radar; Railway ballast; Track geometry; Track inspection","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:547765f6-caf2-4157-845e-410b80f8ae49","http://resolver.tudelft.nl/uuid:547765f6-caf2-4157-845e-410b80f8ae49","Core–shell structured gold nanoparticles as carrier for 166Dy/166Ho in vivo generator","Wang, R. (TU Delft RST/Applied Radiation & Isotopes); Ponsard, Bernard (Belgian Nuclear Research Centre); Wolterbeek, H.T. (TU Delft RST/Applied Radiation & Isotopes); Denkova, A.G. (TU Delft RST/Applied Radiation & Isotopes)","","2022","Background: Radionuclide therapy (RNT) has become a very important treatment modality for cancer nowadays. Comparing with other cancer treatment options, sufficient efficacy could be achieved in RNT with lower toxicity. β− emitters are frequently used in RNT due to the long tissue penetration depth of the β− particles. The dysprosium-166/holmium-166 (166Dy/166Ho) in vivo generator shows great potential for treating large malignancies due to the long half-life time of the mother nuclide 166Dy and the emission of high energy β− from the daughter nuclide 166Ho. However, the internal conversion occurring after β− decay from 166Dy to 166Ho could cause the release of about 72% of 166Ho when 166Dy is bound to conventional chelators. The aim of this study is to develop a nanoparticle based carrier for 166Dy/166Ho in vivo generator such that the loss of the daughter nuclide 166Ho induced by internal conversion is prevented. To achieve this goal, we radiolabelled platinum-gold bimetallic nanoparticles (PtAuNPs) and core–shell structured gold nanoparticles (AuNPs) with 166Dy and studied the retention of both 166Dy and 166Ho under various conditions. Results: The 166Dy was co-reduced with gold and platinum precursor to form the 166DyAu@AuNPs and 166DyPtAuNPs. The 166Dy radiolabelling efficiency was determined to be 60% and 70% for the two types of nanoparticles respectively. The retention of 166Dy and 166Ho were tested in MiliQ water or 2.5 mM DTPA for a period of 72 h. In both cases, more than 90% of both 166Dy and 166Ho was retained. The results show that the incorporation of 166Dy in AuNPs can prevent the escape of 166Ho released due to internal conversion. Conclusion: We developed a chelator-free radiolabelling method for 166Dy with good radiolabelling efficiency and very high stability and retention of the daughter nuclide 166Ho. The results from this study indicate that to avoid the loss of the daughter radionuclides by internal conversion, carriers composed of electron-rich materials should be used.","Dysprosium-166; Gold nanoparticle; Holmium-166; In vivo generator; Internal conversion; Radionuclide therapy; OA-Fund TU Delft","en","journal article","","","","","","","","","","","RST/Applied Radiation & Isotopes","","",""
"uuid:e7d42dd7-48e2-49b9-8c1a-c3fd4356befe","http://resolver.tudelft.nl/uuid:e7d42dd7-48e2-49b9-8c1a-c3fd4356befe","Rational hyperelastic modelling of elastic poured compound for the failure analysis of embedded rail system","Wang, L. (TU Delft Railway Engineering; Southwest Jiaotong University); Li, S. (TU Delft Railway Engineering); Wang, Ping (Southwest Jiaotong University); Chen, Rong (Southwest Jiaotong University); Li, Z. (TU Delft Railway Engineering)","","2022","The continuous homogeneous rail constraint of embedded rail system (ERS) is realized by the encapsulation of rails with the elastic poured compound (EPC) which is a composite material. Previous treatment of EPC as linear elastic material was insufficient in the failure analysis of ERS. In this work, a hyperelastic model is developed to describe the mechanical properties of the EPC with engineering strain up to 150%. Physical tests of uniaxial tension, planar tension and quadruple shear are conducted. A 4-parameter Ogden model is determined by curve fitting and validated with a progressive validation strategy, and then is applied to the failure analysis of ERS. It is found that the material nonlinearity of EPC contributes noticeably to the decrease of the longitudinal stiffness of ERS. The 2nd debonding is more probably caused by the failure of adhesive at the interface between EPC and rail rather than EPC itself.","composite material; elastic poured compound; Embedded rail system; failure analysis; finite element method; hyperelastic model","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:15191ad7-5f97-4033-bd86-878f78a68824","http://resolver.tudelft.nl/uuid:15191ad7-5f97-4033-bd86-878f78a68824","Gravity center change of carbon emissions in Chinese residential building sector: Differences between urban and rural area","Wang, Jiebing (Chongqing University); You, K. (TU Delft Design & Construction Management); Qi, Lingling (Chongqing University); Ren, Hong (Chongqing University)","","2022","In China, dynamic spatial–temporal evolution and urban–rural gap in carbon emissions of residential building sector are crucial for understanding the current state, which is faced with great challenges related to emission mitigation. To overcome the challenge, this study employed the gravity center model to explore spatial–temporal evolution of carbon emissions and analyzed the driving factories leading the differences between urban residential buildings and rural residential buildings via decomposition analysis. Meanwhile, Tapio decoupling index is used to predict the future movement of the gravity center. Our results indicated that: (i) the carbon emissions gravity center of both residential building types tends to move south; (ii) the northeast and northwest regions play the largest role in driving the gravity center movement of urban residential buildings and rural residential buildings, respectively; (iii) per capita disposable income is the primary factors affecting the gravity center movement. (iv) the gravity center of both residential building types might tend to move westward in the future. Overall, this study attempts to remedy the current lack of research pertaining to spatial–temporal evolution laws governing carbon emissions in the Chinese residential building sector and provides a reference point for the implementation of targeted urban and rural emission reduction policies.","Carbon emissions; Gravity center model; Residential building; Spatial–temporal logarithmic mean Divisia index; Tapio decoupling analysis","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:4c6da9fa-794e-4ad3-b561-be2115000def","http://resolver.tudelft.nl/uuid:4c6da9fa-794e-4ad3-b561-be2115000def","BERT Rankers are Brittle: A Study using Adversarial Document Perturbations","Wang, Yumeng (L3S); Lyu, Lijun (L3S); Anand, A. (TU Delft Web Information Systems)","","2022","Contextual ranking models based on BERT are now well established for a wide range of passage and document ranking tasks. However, the robustness of BERT-based ranking models under adversarial inputs is under-explored. In this paper, we argue that BERT-rankers are not immune to adversarial attacks targeting retrieved documents given a query. Firstly, we propose algorithms for adversarial perturbation of both highly relevant and non-relevant documents using gradient-based optimization methods. The aim of our algorithms is to add/replace a small number of tokens to a highly relevant or non-relevant document to cause a large rank demotion or promotion. Our experiments show that a small number of tokens can already result in a large change in the rank of a document. Moreover, we find that BERT-rankers heavily rely on the document start/head for relevance prediction, making the initial part of the document more susceptible to adversarial attacks. More interestingly, we find a small set of recurring adversarial words that when added to documents result in successful rank demotion/promotion of any relevant/non-relevant document respectively. Finally, our adversarial tokens also show particular topic preferences within and across datasets, exposing potential biases from BERT pre-training or downstream datasets.","adversarial attack; bert; biases; neural networks; ranking","en","conference paper","Association for Computing Machinery (ACM)","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Web Information Systems","","",""
"uuid:ae3a739d-fca4-4d2a-bc2c-1ca576fe5faa","http://resolver.tudelft.nl/uuid:ae3a739d-fca4-4d2a-bc2c-1ca576fe5faa","Assessment of architectures for Automatic Train Operation driving functions","Wang, Z. (TU Delft Transport and Planning); Quaglietta, E. (TU Delft Transport and Planning); Bartholomeus, Maarten G.P. (ProRail); Goverde, R.M.P. (TU Delft Transport and Planning)","","2022","Automatic Train Operation (ATO) is well-known in urban railways and gets increasing interest from mainline railways at present to improve capacity and punctuality. A main function of ATO is the train trajectory generation that specifies the speed profile over the given running route considering the timetable and the characteristics of the train and infrastructure. This paper proposes and assesses different possible ATO architecture configurations through allocating the intelligent components on the trackside or onboard. The set of analyzed ATO architecture configurations is based on state-of-the-art architectures proposed in the literature for the related Connected Driver Advisory System (C-DAS). Results of the SWOT analysis highlight that different ATO configurations have diverse advantages or limitations, depending on the type of railway governance and the technological development of the existing railway signaling and communication equipment. In addition, we also use the results to spotlight operational, technological, and business advantages/limitations of the proposed ATO-over-ETCS architecture that is being developed by the European Union Agency for Railways (ERA) and provide a scientific argumentation for it.","ATO-over-ETCS; Automatic Train Operation; Connected Driver Advisory System; SWOT; Train Path Envelope; Train trajectory generation","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:ca74312e-b860-4ece-8a05-b51886e820f2","http://resolver.tudelft.nl/uuid:ca74312e-b860-4ece-8a05-b51886e820f2","Intravascular optical coherence elastography","Wang, Tianshi (Erasmus MC); Pfeiffer, Tom (University of Lübeck); Akyildiz, A.C. (TU Delft Medical Instruments & Bio-Inspired Technology; Erasmus MC); van Beusekom, Heleen M.M. (Erasmus MC); Huber, Robert (University of Lübeck); van der Steen, A.F.W. (TU Delft ImPhys/Medical Imaging; Erasmus MC; Chinese Academy of Sciences); Soest, Gijs Van (Erasmus MC)","","2022","Optical coherence elastography (OCE), a functional extension of optical coherence tomography (OCT), visualizes tissue strain to deduce the tissue’s biomechanical properties. In this study, we demonstrate intravascular OCE using a 1.1 mm motorized catheter and a 1.6 MHz Fourier domain mode-locked OCT system. We induced an intraluminal pressure change by varying the infusion rate from the proximal end of the catheter. We analysed the pixel-matched phase change between two different frames to yield the radial strain. Imaging experiments were carried out in a phantom and in human coronary arteries in vitro. At an imaging speed of 3019 frames/s, we were able to capture the dynamic strain. Stiff inclusions in the phantom and calcification in atherosclerotic plaques are associated with low strain values and can be distinguished from the surrounding soft material, which exhibits elevated strain. For the first time, circumferential intravascular OCE images are provided side by side with conventional OCT images, simultaneously mapping both the tissue structure and stiffness.","","en","journal article","","","","","","","","","","","Medical Instruments & Bio-Inspired Technology","","",""
"uuid:e7d08124-18f9-4f12-a944-d560094ab6cf","http://resolver.tudelft.nl/uuid:e7d08124-18f9-4f12-a944-d560094ab6cf","Putting precision and elegance in enzyme immobilisation with bio-orthogonal chemistry","Pei, Xiaolin (Hangzhou Normal University); Luo, Zhiyuan (Hangzhou Normal University); Qiao, Li (Hangzhou Normal University); Xiao, Qinjie (Hangzhou Normal University); Zhang, Pengfei (Hangzhou Normal University); Wang, Anming (Hangzhou Normal University); Sheldon, R.A. (TU Delft BT/Biocatalysis; University of Witwatersrand)","","2022","The covalent immobilisation of enzymes generally involves the use of highly reactive crosslinkers, such as glutaraldehyde, to couple enzyme molecules to each other or to carriers through, for example, the free amino groups of lysine residues, on the enzyme surface. Unfortunately, such methods suffer from a lack of precision. Random formation of covalent linkages with reactive functional groups in the enzyme leads to disruption of the three dimensional structure and accompanying activity losses. This review focuses on recent advances in the use of bio-orthogonal chemistry in conjunction with rec-DNA to affect highly precise immobilisation of enzymes. In this way, cost-effective combination of production, purification and immobilisation of an enzyme is achieved, in a single unit operation with a high degree of precision. Various bio-orthogonal techniques for putting this precision and elegance into enzyme immobilisation are elaborated. These include, for example, fusing (grafting) peptide or protein tags to the target enzyme that enable its immobilisation in cell lysate or incorporating non-standard amino acids that enable the application of bio-orthogonal chemistry.","","en","review","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:710d628c-8363-41e6-b1f7-fe32341d271d","http://resolver.tudelft.nl/uuid:710d628c-8363-41e6-b1f7-fe32341d271d","An Ensemble Learning Framework for Vehicle Trajectory Prediction in Interactive Scenarios","Li, Z. (TU Delft Transport and Planning; Beijing Institute of Technology); Lin, Yunlong (Beijing Institute of Technology); Cheng, Gong (Beijing Institute of Technology); Wang, X. (TU Delft Transport and Planning); Liu, Qi (Beijing Institute of Technology); Gong, Jianwei (Beijing Institute of Technology); Lu, Chao (Beijing Institute of Technology)","","2022","Precisely modeling interactions and accurately predicting trajectories of surrounding vehicles are essential to the decision-making and path-planning of intelligent vehicles. This paper proposes a novel framework based on ensemble learning to improve the performance of trajectory predictions in interactive scenarios. The framework is termed Interactive Ensemble Trajectory Predictor (IETP). IETP assembles interaction-aware trajectory predictors as base learners to build an ensemble learner. Firstly, each base learner in IETP observes historical trajectories of vehicles in the scene. Then each base learner handles interactions between vehicles to predict trajectories. Finally, an ensemble learner is built to predict trajectories by applying two ensemble strategies on the predictions from all base learners. Predictions generated by the ensemble learner are final outputs of IETP. In this study, three experiments using different data are conducted based on the NGSIM dataset. Experimental results show that IETP improves the predicting accuracy and decreases the variance of errors compared to base learners. In addition, IETP exceeds baseline models with 50% of the training data, indicating that IETP is data-efficient. Moreover, the implementation of IETP is publicly available at https://github.com/BIT-Jack/IETP.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Transport and Planning","","",""
"uuid:eb980480-c76c-4df7-a7e8-fbf3a1e73e71","http://resolver.tudelft.nl/uuid:eb980480-c76c-4df7-a7e8-fbf3a1e73e71","Fast-responsive capsule based on two soluble components for self-healing concrete","Gao, Jian (Southeast University); Jin, Peng (Southeast University); Zhang, Yuze (Southeast University); Dong, H. (TU Delft Materials and Environment); Wang, Ruixing (Southeast University)","","2022","Due to low activity or long mineralization time, traditional mineral agents for self-healing concrete generally need a long time to achieve a desired repair efficiency. Inspired by epoxy resin AB glue which can consolidate in a short time when mixing the two components together, a novel type of fast-responsive capsules based on two soluble components was designed for self-healing concrete. Component A (sodium carbonate) and component B (calcium acetate) were encapsulated in two different groups of capsules, respectively, coated with three layers consisting of epoxy resin and fine sands to achieve superior waterproof and alkali resistance properties. After rupture of the capsules, the rapid response with respect to core material dissolution and precipitation can be realized in presence of water, by which the cracks below 200 μm can be healed in 3 days. Super absorbent resin (SAP) embedded in the capsules could expand in contact with water, and further improve the self-healing efficiency of the capsules by blocking the crack.","Composite-wall structure; Double-component; Fast-responsive capsule; Self-healing","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Materials and Environment","","",""
"uuid:0fe1f741-00cc-4cf1-a5b8-4842ccdd2599","http://resolver.tudelft.nl/uuid:0fe1f741-00cc-4cf1-a5b8-4842ccdd2599","A theoretical study of atmospheric pollutant NO2 on as-doped monolayer WS2 based on DFT method","Hou, Shuhan (Southern University of Science and Technology); Wang, Zhaokun (Southern University of Science and Technology); Yang, Huiru (Southern University of Science and Technology; Harbin Institute of Technology); Jiang, Jing (Fudan University); Gao, Chenshan (Southern University of Science and Technology); Liu, Yufei (Chongqing University); Tang, Xiaosheng (Chongqing University of Posts and Telecommunications); Ye, H. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology)","","2022","For the relevant properties of pristine and doped (Si, P, Se, Te, As) monolayer WS2 before and after the adsorption of CO, CO2, N2, NO, NO2 and O2, density functional theory (DFT) calculations are made. Calculation results reveal that the monolayer WS2 doped with P and As atoms can be substrate materials for NO and NO2 gas sensors. However, after the subsequent CDD and ELF calculations, it is found that P-doped monolayer WS2 adsorbs NO and NO2 in a chemical way, while As-doped monolayer WS2 adsorbs NO and NO2 in a physical way. Also, the charge transfer between As-doped monolayer WS2 and NO is relatively small and not easily detected. Besides, As-doped monolayer WS2 system exhibits greater differences in optical properties (the imaginary part of reflectivity and dielectric function) before and after the adsorption of NO2 gas than before and after adsorption of NO gas. These differences in optical properties assist sensor devices in making gas adsorption-related judgments. Through the analysis of the recovery time, DOS and PDOS, As-doped monolayer WS2 is also verified to be a promising NO2 sensing material, whose recovery time is calculated to be as short as 0.169 ms at 300 K.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Components, Technology and Materials","","",""
"uuid:7ba50857-075e-442d-860c-7f8860d1e2c8","http://resolver.tudelft.nl/uuid:7ba50857-075e-442d-860c-7f8860d1e2c8","Bringing Manufacturing into the MDO domain using MBSE","van der Laan, Ton (Fokker/GKN Aerospace); van Manen, Bas (Fokker/GKN Aerospace); Bruggeman, A.M.R.M. (TU Delft Flight Performance and Propulsion); Wang, Z. (TU Delft Aerospace Structures & Computational Mechanics); Peeters, D.M.J. (TU Delft Aerospace Structures & Computational Mechanics); Sonneveld, J.S. (TU Delft Flight Performance and Propulsion); Timmermans, Huub (Royal Netherlands Aerospace Centre NLR)","","2022","Most MDO problems currently do not include manufacturing as an optimization domain. Within the H2020 project AGILE 4.0 the intent is to bring manufacturing into the MDO domain using MBSE techniques developed within the project. To demonstrate how manufacturing can be brought into the MDO domain application cases are set up that resemble MDO problems from industry. In this paper, the MDO techniques will be used for the design of a Flap for a regional jet. The manufacturing aspect is represented by including the manufacturing cost of the flap in a Design Of Experiments (DOE). In this DOE different flap kinematic mechanisms and different flap sizes and paths are explored. The DOE is set up using the MDO toolset developed within AGILE 4.0. It allows for an automatic definition of the DOE workflow. The DOE results show that the choice of flap configuration has a significant effect on the Flap manufacturing cost, the flap wright and the landing performance of the aircraft. Next steps will be to investigate more flap configurations, improved the manufacturing cost model used and to set up a true flap optimization.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Flight Performance and Propulsion","","",""
"uuid:faee36bd-a712-4bb8-a70e-c2ba0d237632","http://resolver.tudelft.nl/uuid:faee36bd-a712-4bb8-a70e-c2ba0d237632","Composition regulation of composite materials in laser powder bed fusion additive manufacturing","Yao, Dengzhi (Northeastern University); Wang, Ju (Northeastern University); Cai, Yao (Northeastern University); Zhao, Tingting (Dalian University of Technology); An, Xizhong (Northeastern University); Zhang, Hao (Northeastern University); Fu, Haitao (Northeastern University); Yang, Xiaohong (Northeastern University); Zou, Qingchuan (Northeastern University); Wang, L. (TU Delft Resources & Recycling)","","2022","Understanding and controlling the composition segregation during powder spreading is of key importance in the additive manufacturing (AM) of composite materials. Under this circumstance, the segregation behavior of WC/316 L composite powders during spreading in laser powder bed fusion (LPBF) AM was numerically investigated by the discrete element method. The effects of process conditions (i.e., spreader velocity and geometry) and powder properties (i.e., size and shape of the WC powder) on the powder bed composition segregation and related characteristics were systematically analyzed. Corresponding mechanisms were identified from microscopic scale in terms of particle velocity, motion trajectory, mechanical behavior, and energy information. Finally, proper solutions in designing and constructing WC/316 L composite materials with desired gradient structures were proposed. The results show that the small blade velocity (V) will enhance the negative segregation, increase the average packing density ρ¯, and decrease uniformity ρvc in the WC/316 L composite powder bed. Compared with the blade, the roller can increase the negative segregation (Seroller = −0.027 < Seblade = −0.019) and the average packing density (ρ¯roller = 0.31>ρ¯blade = 0.20). When the WC/316 L size ratio increases from 25 μm/45 μm to 45 μm/45 μm, the negative segregation becomes weaker, and its value increases from −0.084 to −0.007. When the size ratio increases to 65 μm/45 μm, the powder behaves positive segregation with Semax = 0.017; in this case, the packing density is the lowest (0.14), and the uniformity is the worst (0.17). In comparison with spherical shape, polyhedral WC powder can reduce the negative segregation of the powder bed (Sesphere = −0.019 < Sepolyhedron = −0.008), while the WC shape has less effect on the packing density and uniformity. The density difference of the WC and 316 L powders leads to the difference in energy and force, resulting in different motion and segregation behaviors in the composite powder bed. For WC/316 L composite powder with a fixed composition, the condition of V = 0.025 m/s, WC/316 L size ratio = 25 μm/45 μm, roller spreader, and spherical WC can realize the proper composition gradient along the spreading direction in the composite powder bed.","LPBF additive manufacturing; Numerical simulation; Powder spreading; Segregation; WC/316L composite material","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Resources & Recycling","","",""
"uuid:150085fa-18cd-4e2b-ad0a-202312530a83","http://resolver.tudelft.nl/uuid:150085fa-18cd-4e2b-ad0a-202312530a83","Conductive Co-based metal organic framework nanostructures for excellent potassium- and lithium-ion storage: Kinetics and mechanism studies","Mao, Pengcheng (Northeastern University); Fan, Huilin (Northeastern University); Liu, Chang (Northeastern University); Lan, Gongxu (Northeastern University); Huang, Wei (Hunan Agricultural University); Li, Zhipeng (University of Science and Technology Beijing); Amin Hassan, H.M. (TU Delft EKL Equipment; Zagazig University); Zheng, Runguo (Northeastern University); Wang, Zhiyuan (Northeastern University); Sun, Hongyu (Northeastern University); Liu, Yanguo (Northeastern University)","","2022","Thanks to the low cost and earth's abundant potassium resources, potassium ion batteries (PIBs) have attracted much interest as alternative energy storage devices. However, there is still a great challenge to develop suitable anode materials for PIBs with high specific capacity, fast charge/discharge and stable ion storage. Nowadays, conductive metal-organic frameworks (c-MOFs) with excellent physicochemical properties are employed for different electrochemical applications, but the study of their potassium storage performance remains unknown, and the detailed potassium storage mechanism needs to be explored. Herein, nanostructured Co3(HHTP)2 c-MOF (Co-CAT MOF, HHTP: 2,3,6,7,10,11-hexahydroxytriphenylene) is synthesized by a liquid-phase method and evaluated as the anode for PIBs. The active sites and open pathways in the conductive Co-CAT MOF promote ion diffusion and electron transfer, exhibiting high reversible specific capacity (332 mA h g−1 at 0.1 A g−1), excellent long-cycle stability (230 mA h g−1 at the current density of 1.0 A g−1 after 700 cycles) and outstanding rate performance (165 mA h g−1 at 4.0 A g−1), which is superior to the typical PIB anodes. Combined with different ex situ characterization techniques, the potassium storage mechanism based on 8-electron transfer is revealed. Furthermore, Co-CAT MOF exhibits excellent Li-ion storage performance. In the half-cell, the Co-CAT MOF electrode displays a high reversible capacity of 800 mA h g−1 at 200 mA g−1. In addition, the Co-CAT//LiCoO2 full cell cycles for 100 cycles at 200 mA h g−1. It is believed that Co-CAT MOF is a promising electrode material for potassium/lithium storage, and the proposed ion storage mechanism can be used to discover other MOF-based electrodes for energy storage.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","EKL Equipment","","",""
"uuid:b3425e89-0087-4f5b-9ffc-7e8845846209","http://resolver.tudelft.nl/uuid:b3425e89-0087-4f5b-9ffc-7e8845846209","Physicochemical model for simulating the chemical processes during the crystallization of minerals from spent ion exchange regenerant","Boncz, M.A. (TU Delft Sanitary Engineering; Universidade Federal de Mato Grosso do Sul); van Linden, N. (TU Delft Sanitary Engineering); Haidari, A.H. (TU Delft Sanitary Engineering); Wang, Y. (TU Delft Civil Engineering & Geosciences); Spanjers, H. (TU Delft Sanitary Engineering)","","2022","Traditionally, industrial processes produce wastes that, even though often containing useful materials, are discarded, contributing to environmental pollution and depletion of natural resources. An example of such wastes are brines, flows of concentrated salts, produced in water treatment processes, which are now routinely discharged into receiving water bodies. Brines however can also be considered as flows of reusable materials which should be recovered, and the Zero Brine cooperation project aims to develop processes for that purpose. For a demineralized water production plant in the port of Rotterdam (the Netherlands), a closed water processing cycle was proposed to treat the large volume of spent Ion Exchange (IEX) regenerant brine which, apart from recovering demineralized water, is also intended to produce magnesium (Mg2+) and calcium (Ca2+) salts, with the highest purity possible, from the otherwise discharged brine. The process scheme includes nanofiltration (NF) for separating mono- and multivalent ions, followed by sequential chemical precipitation of Mg2+ and Ca2+ ions from the NF concentrate, and production of demineralized water by evaporation of the NF permeate. The concentrate of monovalent ions produced in the evaporator, essentially a concentrated sodium chloride solution, in its turn might be reused for IEX regeneration. Part of the supernatant of the sequential precipitation may be fed to the evaporator as well, but bleeding the other part of this supernatant is essential in order to maintain process stability, avoid accumulation of minor pollutants, and reduce scaling. In this study, various scenarios to operate the process were modeled, using PHREEQC and Excel. According to the simulation results, recovery of ≈97% of Mg2+ and Ca2+ is possible, the latter with a higher purity than the former. The main factors affecting the results are the concentration of carbonate present in the spent IEX regenerant, as well as characteristics of the NF membrane and the dosing of sodium hydroxide in the sequential precipitation steps. The results of the simulations were used for the design and operation of a pilot plant, comprising all mentioned process steps.","Brines; Closed cycle; Metal recovery; Phreeqc; Sequential crystallisation","en","journal article","","","","","","","","","Civil Engineering & Geosciences","","Sanitary Engineering","","",""
"uuid:82a0e818-fcfd-4078-ac03-e63637930b0e","http://resolver.tudelft.nl/uuid:82a0e818-fcfd-4078-ac03-e63637930b0e","A Queuing Network Model of a Multi-Airport System Based on Point-Wise Stationary Approximation","Zhao, Xifan (Nanjing University of Aeronautics and Astronautics); Wang, Yanjun (Nanjing University of Aeronautics and Astronautics); Li, L. (TU Delft Air Transport & Operations; City University of Hong Kong); Delahaye, Daniel (Ecole Nationale de l’Aviation Civile (ENAC))","","2022","A multiple-airport system (MAS) consists of more than two airports in a metropolitan area under a large block of terminal airspace that is managed by one or two air traffic control units. When the capacity of an airport or of the terminal airspace drops, flight delays occur in the MAS system. A quick estimation and predication of traffic congestion in the MAS is important yet challenging. This paper aims to develop a queuing network model of MAS using point-wise stationary queues. The model analyzes the changes of non-stationary queues under the principle of flow conservation to capture flight delay propagation in the system. Regression analyses are performed to examine the relationship between the arrival and departure efficiencies of different airports. The model is validated with the data of Guangdong–Hong Kong–Macao Greater Bay Area airports. Simulation results show that the model can effectively estimate flight delays in the MAS.","airspace congestion; delay propagation; M/G/1 system; multiple airport system; queuing network model","en","journal article","","","","","","","","","","","Air Transport & Operations","","",""
"uuid:70709533-f6c9-4e01-85c5-6a2bd1fab92e","http://resolver.tudelft.nl/uuid:70709533-f6c9-4e01-85c5-6a2bd1fab92e","Electronic Properties and Phase Transition in the Kagome Metal Yb0.5Co3Ge3","Wang, Y. (TU Delft QN/Quantum Nanoscience; TU Delft QN/Ali Lab; Kavli institute of nanoscience Delft); McCandless, Gregory T. (Baylor University); Wang, Xiaoping (Oak Ridge National Laboratory); Thanabalasingam, Kulatheepan (Baylor University); Wu, H. (TU Delft QN/Quantum Nanoscience; TU Delft QN/Ali Lab; Kavli institute of nanoscience Delft); Bouwmeester, D. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft); van der Zant, H.S.J. (TU Delft QN/Quantum Nanoscience; TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft); Ali, M.N. (TU Delft QN/Quantum Nanoscience; TU Delft QN/Ali Lab; Kavli institute of nanoscience Delft); Chan, C.L. (Baylor University)","","2022","The Kagome lattice is an important fundamental structure in condensed matter physics for investigating the interplay of electron correlation, topology, and frustrated magnetism. Recent work on Kagome metals in the AV3Sb5 (A = K, Rb, and Cs) family has shown a multitude of correlation-driven distortions, including symmetry breaking charge density waves and nematic superconductivity at low temperatures. Here, we study the new Kagome metal Yb0.5Co3Ge3 and find a temperature-dependent kink in the resistivity that is highly similar to the AV3Sb5 behavior and is commensurate with an in-plane structural distortion of the Co Kagome lattice along with a doubling of the c-axis. The symmetry is lower below the transition temperature, with a breaking the in-plane mirror planes and C6 rotation, while gaining a screw axis along the c-direction. At very low temperatures, anisotropic negative magnetoresistance is observed, which may be related to anisotropic magnetism. This raises questions about the types of the distortions in Kagome nets and their resulting physical properties including superconductivity and magnetism.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-02-02","","QN/Quantum Nanoscience","QN/Ali Lab","","",""
"uuid:bfb7f1d1-a3b3-4583-a33c-32eef08e9b20","http://resolver.tudelft.nl/uuid:bfb7f1d1-a3b3-4583-a33c-32eef08e9b20","Mitigating Electrolyte Flooding for Electrochemical CO2Reduction via Infiltration of Hydrophobic Particles in a Gas Diffusion Layer","Wu, Yuming (University of Queensland); Charlesworth, Liam (University of Queensland); Maglaya, Irving (University of Queensland); Idros, Mohamed Nazmi (University of Queensland); Li, Mengran (TU Delft ChemE/Materials for Energy Conversion and Storage); Burdyny, T.E. (TU Delft ChemE/Materials for Energy Conversion and Storage); Wang, Geoff (University of Queensland); Rufford, Thomas E. (University of Queensland)","","2022","Achieving operational stability at high current densities remains a challenge in CO2 electrolyzers due to flooding of the gas diffusion layer (GDL) that supports the electrocatalyst. We mitigated electrode flooding at high current densities using a vacuum-assisted infiltration method to embed 200-400 nm-sized polytetrafluoroethylene (PTFE) particles at the interface of the microporous layer (MPL) and carbon cloth in a commercial GDL. In CO2 electrolysis to CO over a silver nanoparticle catalyst on the GDL, the PTFE-embedded GDL not only just exhibited less than 10% of the electrolyte seepage rates observed in untreated GDLs at a current density of 300 mA·cm-2 but also expanded the electrochemical active area across the testing conditions. The PTFE-embedded GDL also maintained a Faradaic efficiency for CO2 electrolysis to CO above 80% for more than 100 h at 100 mA·cm-2, which was a 50-fold improvement in the stable operation time of the electrolyzer.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:19a8ef83-67b9-4a2f-a43d-b7bbd5aa40c8","http://resolver.tudelft.nl/uuid:19a8ef83-67b9-4a2f-a43d-b7bbd5aa40c8","Microwave heating mechanism and self-healing performance of asphalt mixture with basalt and limestone aggregates","Wang, Fu (Wuhan Institute of Technology); Zhu, Hongbin (Wuhan Institute of Technology); Shu, Benan (Foshan Transportation Science and Technology Co.); Li, Yuanyuan (Wuhan Institute of Technology); Gu, Dengjun (Wuhan Institute of Technology); Gao, Y. (TU Delft Pavement Engineering); Chen, Anqi (Wuhan University of Technology); Feng, Jianlin (Wuhan Institute of Technology); Wu, Shaopeng (Wuhan University of Technology)","","2022","Traditional asphalt mixtures can't absorb microwave energy efficiently, which limits the development of microwave heating technology in the field of road maintenance. Based on the microwave heating characteristics of basalt aggregates, the overall microwave self-healing rate of the asphalt mixture can be enhanced. The basalt was tested by XRF, XPS, XRD and electromagnetic parameters to reveal its microwave heating mechanism. Through the heating rate test, SCB test and fatigue test of asphalt mixture, its heating characteristics, flexural strength, fatigue resistance and self-healing performance were studied. The results showed that the excellent wave-absorbing properties of basalt are highly correlated with the elements of Si, Fe and Al. Its TanδM was slightly larger than TanδE, which indicated that basalt can absorb microwave energy through dielectric loss and magnetic loss. The aggregate type and particle size both affected the microwave heating rate of the aggregates. After microwave heating, the flexural strength and fatigue resistance of asphalt mixture with basalt and limestone aggregates can recover at least 65% and 23% respectively.","Aggregates; Asphalt mixture; Basalt; Heating characteristics; Microwave heating mechanism; Self-healing performance","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Pavement Engineering","","",""
"uuid:14102983-abab-4e23-a7cd-724418636b7c","http://resolver.tudelft.nl/uuid:14102983-abab-4e23-a7cd-724418636b7c","The Effect of Wet Treatment on the Distribution and Leaching of Heavy Metals and Salts of Bottom Ash from Municipal Solid Waste Incineration","Zhu, Yonghao (Zhejiang University); Hu, Yanjun (Zhejiang University); Guo, Qianqian (Zhejiang University); Zhao, Lingqin (Zhejiang University); Li, Lianming (Jiaxing New Jies Heat & Power Co, Jiaxing); Wang, Y. (Jiaxing New Jies Heat & Power Co, Jiaxing); Hu, Guixiang (Zhejiang University); Wibowo, Haryo (Zhejiang University); Di Maio, F. (TU Delft Resources & Recycling)","","2022","One of the main challenges of bottom ash reutilization is heavy metal and salts' leaching potential. The effect of wet treatment on chemical composition and leaching toxicity of bottom ash were investigated in this study to mitigate this leaching potential. Batch leaching and column leaching tests were first conducted to investigate the leaching behavior of the targeted elements (Cu, Zn, Ni, Cl-, and SO42-) from raw bottom ash and treated bottom ash after wet treatment. X-ray fluorescence analysis was used to analyze the chemical composition of bottom ash, and sequential extraction procedure (SEP) operation was done to analyze the chemical species of the heavy metals of bottom ash. The obtained results showed that the wet treatment applied on raw bottom ash posed a slight influence on the concentration of most of the major elements, 5.57-18.18%. SEP results showed the acid extractable Zn that accounted for 22.4-24.5% of the total Zn, and the iron manganese oxide bound Ni was 25.2-28.4%, and the organic matter bound Cu was 21.4-31.7%. The wet treatment reduced the concentrations and leachable amount of the targeted pollutants, which could decrease the leaching concentration of Cu by 77.1%, Zn by 34.7%, Ni by 100%, Cl by 30.1%, and SO42- by 51.4% based on the batch leaching tests under acid condition. The column leaching tests also suggest that wet treatment decreases Cu, Zn, and Cl- leaching concentration in bottom ash. This indicates that wet treatment improves the suitability of municipal solid waste incineration bottom ash for reutilization in China.","batch leaching; bottom ash; column leaching; heavy metal; municipal solid waste incineration","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Resources & Recycling","","",""
"uuid:0ee8aacc-17f9-4192-b75b-7ddd38385a19","http://resolver.tudelft.nl/uuid:0ee8aacc-17f9-4192-b75b-7ddd38385a19","Manipulate energy transport via fluorinated spacers towards record-efficiency 2D Dion-Jacobson CsPbI3 solar cells","Lei, Yutian (Lanzhou University); Li, Zhen-Hua (Lanzhou University); Wang, H. (TU Delft Photovoltaic Materials and Devices); Wang, Qian (Lanzhou University); Peng, Guoqiang (Lanzhou University); Xu, Youkui (Lanzhou University); Zhang, Haihua (Tianjin University); Wang, Gang (Ningbo University); Ding, Liming (National Center for Nanoscience and Technology (NCNST)); Jin, Zhiwen (Lanzhou University)","","2022","Two-dimensional (2D) Dion-Jacobson (D-J)-type cesium lead iodide CsPbI 3 perform remarkably in terms of stability. However, the complex interactions between spacer and inorganic layers limit its excellent progress in perovskite solar cells (PSCs). Herein, starting from the considerable structural diversity of organic spacers, we engineer 2D CsPbI 3 with fine-tuning functionalities. Specifically, for the first time we embedded fluorinated aromatic cations in 2D D-J CsPbI 3, and successfully applied it into construction of high-performance PSCs. Compared with constitutive 1,4-diaminobenzene (PDA), the fluorinated 2-fluorobenzene-1,4-diamine (F-PDA) component greatly expands the dipole moment from 0.59D to 3.47D, which reduces the exciton binding energy of the system. A theoretical study shows that the spacer layer and inorganic plane are more enriched with charge accumulation in (F-PDA)Cs n– 1Pb nI 3 n+ 1. The results show that (F-PDA)Cs n– 1Pb nI 3 n+ 1 demonstrates more significant charge transfer between organic and inorganic layers than (PDA)Cs n– 1Pb nI 3 n+ 1, and it is confirmed in the femtosecond transient absorption experiment. Moreover, the interactions of the fluorinated spacer with the [PbI 6] 4 – plane effectively manipulate the crystallization quality, and thus the ion migration and defect formation of target 2D CsPbI 3 are inhibited. As a result, we obtained a record power conversion efficiency (PCE) beyond 15% for 2D D-J (F-PDA)Cs 3Pb 4I 13 (n = 4) PSCs with significantly improved environmental stability compared with the three-dimensional (3D) counterparts.","Dion-Jacobson CsPbI; Energy transport; Fluorinated spacers; Interaction","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-12-05","","","Photovoltaic Materials and Devices","","",""
"uuid:80ad5e99-66c6-4b1d-9dda-6df3d050750a","http://resolver.tudelft.nl/uuid:80ad5e99-66c6-4b1d-9dda-6df3d050750a","Dynamic Risk Assessment of Chemical Process Systems using System-Theoretic Accident Model and Process (STAMP) and Failure Propagation Model","Sun, H. (TU Delft Safety and Security Science; China University of Petroleum (East China)); Wang, Haiqing (China University of Petroleum (East China)); Yang, M. (TU Delft Safety and Security Science); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Universiteit Antwerpen; Katholieke Universiteit Leuven)","","2022","Chemical process systems involve complex dynamic processes, and the state of the system often fluctuates during the production process. To ensure the continuation of production, these fluctuations are often ignored or processed online instead of shutting down the unit. However, the interdependence between components in the system is strong, and small fluctuations or faults will be propagated to downstream nodes in turn if the fluctuation is omitted or processed online. A large number of accident investigations prove that the system risk increments as the failure propagates. This may eventually cause the entire system to collapse, causing severe casualties, property losses, and environmental damage. However, little attention has been paid to this type of risk. To measure the dynamic risk profile considering the fluctuation of the production process, this paper proposes a new risk assessment model that integrates the system-theoretic accident model and process (STAMP) and the failure propagation model. Firstly, the STAMP is used to model and analyze the system safety of a process system. An approach is then developed to quantify the risk accumulation of the model based on the failure propagation model. The process of the Chevron Richmond refinery crude unit and its associated upstream process is used to demonstrate the application of the proposed approach.","","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:1f8154f7-28f7-46fd-922f-814e25c4a2a1","http://resolver.tudelft.nl/uuid:1f8154f7-28f7-46fd-922f-814e25c4a2a1","A reliable progressive fatigue damage model for life prediction of composite laminates incorporating an adaptive cyclic jump algorithm","Zheng, T. (TU Delft Structural Integrity & Composites; Harbin Institute of Technology); Guo, Licheng (Harbin Institute of Technology); Wang, Zhenxin (AECC Commercial Aircraft Engine Co., Ltd); Benedictus, R. (TU Delft Structural Integrity & Composites); Pascoe, J.A. (TU Delft Structural Integrity & Composites)","","2022","In this paper, a reliable progressive fatigue damage model (PFDM) for predicting the fatigue life of composite laminates is proposed by combining the normalized fatigue life model, nonlinear residual degradation models and fatigue-improved Puck criterion. To balance the accuracy of life predictions and computational efficiency, an adaptive cyclic jump algorithm is developed and implemented within the PFDM. The sensitivity of life prediction to cyclic jump parameter has been greatly reduced by correlating the cyclic jump with the increment time and viscous coefficient. Therefore, the cyclic jump parameter can be arbitrarily selected within a relatively large range to obtain convergent results. When incorporating the adaptive cyclic jump algorithm, there is no need to define a standard for determining the material failure in numerical calculations, which effectively eliminates an artificially induced uncertainty in life predictions. Two sets of experiments are conducted to validate the proposed PFDM. The numerical predictions including static failure strength and fatigue life correlate reasonably well with the available experimental data.","A. Laminate; A. polymer-matrix composites (PMCs); B. Fatigue; C. Finite element analysis (FEA); D. Life prediction","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Structural Integrity & Composites","","",""
"uuid:11e6c14a-afcd-4daa-b7a3-fae550ebb2ed","http://resolver.tudelft.nl/uuid:11e6c14a-afcd-4daa-b7a3-fae550ebb2ed","Fault-tolerant operation of a logical qubit in a diamond quantum processor","Abobeih, M.H.M.A. (TU Delft QID/Taminiau Lab; Kavli institute of nanoscience Delft); Wang, Y. (TU Delft QCD/Terhal Group); Randall, J.A.D. (TU Delft QID/Taminiau Lab; Kavli institute of nanoscience Delft); Loenen, S.J.H. (TU Delft QID/Taminiau Lab; Kavli institute of nanoscience Delft); Bradley, C.E. (TU Delft QID/Taminiau Lab; Kavli institute of nanoscience Delft); Markham, M. (Element Six Innovation); Twitchen, D. J. (Element Six Innovation); Terhal, B.M. (TU Delft QCD/Terhal Group; TU Delft Quantum Computing; Forschungszentrum Jülich GmbH); Taminiau, T.H. (TU Delft QID/Taminiau Lab; Kavli institute of nanoscience Delft)","","2022","Solid-state spin qubits is a promising platform for quantum computation and quantum networks1,2. Recent experiments have demonstrated high-quality control over multi-qubit systems3–8, elementary quantum algorithms8–11 and non-fault-tolerant error correction12–14. Large-scale systems will require using error-corrected logical qubits that are operated fault tolerantly, so that reliable computation becomes possible despite noisy operations15–18. Overcoming imperfections in this way remains an important outstanding challenge for quantum science15,19–27. Here, we demonstrate fault-tolerant operations on a logical qubit using spin qubits in diamond. Our approach is based on the five-qubit code with a recently discovered flag protocol that enables fault tolerance using a total of seven qubits28–30. We encode the logical qubit using a new protocol based on repeated multi-qubit measurements and show that it outperforms non-fault-tolerant encoding schemes. We then fault-tolerantly manipulate the logical qubit through a complete set of single-qubit Clifford gates. Finally, we demonstrate flagged stabilizer measurements with real-time processing of the outcomes. Such measurements are a primitive for fault-tolerant quantum error correction. Although future improvements in fidelity and the number of qubits will be required to suppress logical error rates below the physical error rates, our realization of fault-tolerant protocols on the logical-qubit level is a key step towards quantum information processing based on solid-state spins.","","en","journal article","","","","","","","","","","","QID/Taminiau Lab","","",""
"uuid:3f431b44-b5f0-4976-a85c-de76e1d8ef6c","http://resolver.tudelft.nl/uuid:3f431b44-b5f0-4976-a85c-de76e1d8ef6c","Joint registration of multiple point clouds for fast particle fusion in localization microscopy","Wang, W. (TU Delft ImPhys/Computational Imaging); Heydarian, H. (TU Delft ImPhys/Computational Imaging); Huijben, T.A.P.M. (TU Delft ImPhys/Computational Imaging); Stallinga, S. (TU Delft ImPhys/Imaging Physics); Rieger, B. (TU Delft ImPhys/Computational Imaging)","","2022","Summary: We present a fast particle fusion method for particles imaged with single-molecule localization microscopy. The state-of-the-art approach based on all-to-all registration has proven to work well but its computational cost scales unfavorably with the number of particles N, namely as N2. Our method overcomes this problem and achieves a linear scaling of computational cost with N by making use of the Joint Registration of Multiple Point Clouds (JRMPC) method. Straightforward application of JRMPC fails as mostly locally optimal solutions are found. These usually contain several overlapping clusters that each consist of well-aligned particles, but that have different poses. We solve this issue by repeated runs of JRMPC for different initial conditions, followed by a classification step to identify the clusters, and a connection step to link the different clusters obtained for different initializations. In this way a single well-aligned structure is obtained containing the majority of the particles. Results: We achieve reconstructions of experimental DNA-origami datasets consisting of close to 400 particles within only 10 min on a CPU, with an image resolution of 3.2 nm. In addition, we show artifact-free reconstructions of symmetric structures without making any use of the symmetry. We also demonstrate that the method works well for poor data with a low density of labeling and for 3D data.","","en","journal article","","","","","","","","","","ImPhys/Imaging Physics","ImPhys/Computational Imaging","","",""
"uuid:8d5c7f02-c24f-4283-bded-c986d61cf061","http://resolver.tudelft.nl/uuid:8d5c7f02-c24f-4283-bded-c986d61cf061","Compound flood impact of water level and rainfall during tropical cyclone periods in a coastal city: the case of Shanghai","Xu, H. (TU Delft Hydraulic Structures and Flood Risk; Southern University of Science and Technology; East China Normal University); Tian, Zhan (Southern University of Science and Technology; Pengcheng Laboratory, Shenzhen); Sun, Laixiang (SOAS University of London; University of Maryland); Ye, Qinghua (TU Delft Coastal Engineering; Deltares); Ragno, E. (TU Delft Hydraulic Structures and Flood Risk); Bricker, J.D. (TU Delft Hydraulic Structures and Flood Risk; University of Michigan); Tan, Jinkai (Sun Yat-sen University); Ke, Q. (TU Delft Hydraulic Structures and Flood Risk); Wang, Shuai (Imperial College London)","","2022","Compound flooding is generated when two or more flood drivers occur simultaneously or in close succession. Multiple drivers can amplify each other and lead to greater impacts than when they occur in isolation. A better understanding of the interdependence between flood drivers would facilitate a more accurate assessment of compound flood risk in coastal regions. This study employed the D-Flow Flexible Mesh model to simulate the historical peak coastal water level, consisting of the storm surge, astronomical tide, and relative sea level rise (RSLR), in Shanghai over the period 1961-2018. It then applies a copula-based methodology to calculate the joint probability of peak water level and rainfall during historical tropical cyclones (TCs) and to calculate the marginal contribution of each driver. The results indicate that the astronomical tide is the leading driver of peak water level, followed by the contribution of the storm surge. In the longer term, the RSLR has significantly amplified the peak water level. This study investigates the dependency of compound flood events in Shanghai on multiple drivers, which helps us to better understand compound floods and provides scientific references for flood risk management and for further studies. The framework developed in this study could be applied to other coastal cities that face the same constraint of unavailable water level records.","","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:c7311211-3010-4ded-9607-621575b5ff08","http://resolver.tudelft.nl/uuid:c7311211-3010-4ded-9607-621575b5ff08","Monitoring the Monthly Expansion Pattern of Pioneer Vegetation in Tidal Flats Using a Terrestrial Laser Scanner","Zhan, Y.J. (TU Delft Coastal Engineering; Shanghai Estuarine and Coastal Science Research Center); Aarninkhof, S.G.J. (TU Delft Hydraulic Engineering); Wang, Zhengbing (TU Delft Coastal Engineering); Zhou, Yunxuan (Shanghai Estuarine and Coastal Science Research Center)","","2022","Research on the expansion pattern of pioneer vegetation in tidal flats is important, because this pattern affects the development of both topography and ecology. This study aimed to determine the monthly expansion patterns of seedlings and tussocks by using terrestrial laser scanning (TLS). Overall change process research and spatial analyses of both seedling recruitment and tussock development were carried out in this work. The results show that the overall change in pioneer vegetation reflected an expansion toward the shoreline in the first year and then a northward colonization in the second year. Moreover, positive feedback effects were observed between vegetation colonization and sedimentation accretion. Colonization accelerated the depositional process at the study site. Moreover, sedimentation accretion in the northern subarea, which is located close to the seawall, promoted the colonization of vegetation in this region. A strong spatial relationship was observed between seedling recruitment and tussock development. Tussocks tended to force seedlings to expand outward by squeezing the established space of the seedlings. Moreover, seedlings were densely concentrated within a certain distance from tussocks. The distances between seedlings and tussocks tended to shorten annually as the entire vegetation area underwent the expansion process. The average distance between seedlings was found to be concentrated from 10 to 20 m. The monthly vegetation expansion process was studied on small and medium scales in this work, revealing the advantages of TLS technology in rapidly acquiring data with high resolution and high precision.","Monthly monitoring; seedling and tussock","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","Hydraulic Engineering","Coastal Engineering","","",""
"uuid:8041b3aa-80b3-4a03-8bac-9bd4dbb71d1a","http://resolver.tudelft.nl/uuid:8041b3aa-80b3-4a03-8bac-9bd4dbb71d1a","Temperature-sensing performance of polymer-derived SiAlCN ceramics up to 1000 °C","Shao, Pengfei (Zhengzhou University); Ma, C. (TU Delft RST/Applied Radiation & Isotopes; Zhengzhou University); Han, Daoyang (Zhengzhou University); Liu, Kun (Zhengzhou University); Li, Mingliang (Zhengzhou University); Liang, Yi (Zhengzhou University); Yao, Meng (Zhengzhou University); Wang, Hailong (Zhengzhou University); Zhang, Rui (Zhengzhou University; Luoyang Institute of Science and Technology, Henan); Shao, Gang (Zhengzhou University)","","2022","Temperature sensors that can operate in high-temperature and harsh environments are highly desired. However, this is a great challenge for sensing materials to operate under extreme working conditions because of oxidation and/or corrosion at high temperature. In this study, polymer-derived SiAlCN ceramics were prepared as sensing materials to overcome the abovementioned issues. A SiAlCN ceramic temperature sensor was designed and fabricated, and it performed excellent temperature-sensing properties with high accuracy, high stability, and high repeatability up to 1000 °C. Compared with traditional thermocouples, the SiAlCN ceramic sensor exhibited a faster response rate (a shorter response time). These results showed that SiAlCN ceramic is a promising sensor material for temperature measurement in high-temperature and harsh environments.","Harsh environment; High-temperature sensor; Negative temperature coefficient; Polymer-derived SiAlCN ceramics","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","RST/Applied Radiation & Isotopes","","",""
"uuid:c650e123-84b2-4607-8403-e0c7c1cbfaea","http://resolver.tudelft.nl/uuid:c650e123-84b2-4607-8403-e0c7c1cbfaea","Lightweight and Accurate DNN-Based Anomaly Detection at Edge","Zhang, Qinglong (Beijing Institute of Technology); Han, Rui (Beijing Institute of Technology); Xin, Gaofeng (Beijing Institute of Technology); Liu, Chi Harold (Beijing Institute of Technology); Wang, Guoren (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Data-Intensive Systems)","","2022","Deep neural networks (DNNs) have been showing significant success in various anomaly detection applications such as smart surveillance and industrial quality control. It is increasingly important to detect anomalies directly on edge devices, because of high responsiveness requirements and tight latency constraints. The accuracy of DNN-based solutions rely on large model capacity and thus long training and inference time, making them inapplicable on resource strenuous edge devices. It is hence imperative to scale DNN model sizes in correspondence to the run-time system requirements, i.e., meeting deadlines with minimal accuracy losses, which are highly dependent on the platforms and real-time system status. Existing scaling techniques either take long training time to pre-generate scaling options or disturb the unsteady training process of anomaly detection DNNs, lacking the adaptability to heterogeneous edge systems and incurring low inference accuracies. In this article, we present LightDNN to scale DNN models for anomaly detection applications at edge, featuring high detection accuracies with lightweight training and inference time. To this end, LightDNN quickly extracts and compresses blocks in a DNN, and provides large scaling space (e.g., 1 million options) by dynamically combining these compressed blocks online. At run-time, LightDNN predicts the DNN's inference latency according to the monitored system status, and optimizes the combination of blocks to maximize its accuracy under deadline constraints. We implement and extensively evaluate LightDNN on both CPU and GPU edge platforms using 8 popular anomaly detection workloads. Comparative experiments with state-of-the-art methods show that our approach provides 145.8 to 0.56 trillion times more scaling options without increasing training and inference overheads, thus achieving as much as 15.05% increase in accuracy under the same deadlines.","Anomaly detection; DNN; edge inference; model scaling; predictable latency","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Data-Intensive Systems","","",""
"uuid:7598bc23-968c-4184-bcac-9d84288e9f51","http://resolver.tudelft.nl/uuid:7598bc23-968c-4184-bcac-9d84288e9f51","Statistical mixture design for carbide residue activated blast furnace slag foamed lightweight concrete","Zhang, Hongzhi (Shandong University); He, Yanchen (Shandong University); Wang, Chuan (Shandong Hi-speed Group); Guan, Yanhua (Shandong University); Ge, Zhi (Shandong University); Sun, Renjuan (Shandong University); Ling, Yifeng (Shandong University); Šavija, B. (TU Delft Materials and Environment)","","2022","Carbide residue activated blast furnace slag is a relatively new kind of eco-friendly construction materials. This work addresses the design of foamed lightweight concrete as road embankment material using such material. A statistical mixture design approach was adopted to assess the influence of each ingredient as well as the interaction between these on the spreadability and compressive strength and thus allowing mixture design. The fitted models were validated using analysis of variance, residual analysis and confirmed by the experiments. Afterwards, the proposed models were used to optimize the mixture. The mixture with the highest compressive strength and the maximum content of carbide residue that allows the mixture to meet the required properties were obtained, respectively.","Blast furnace slag; Carbide residue; Foamed lightweight concrete; Statistical mixture design","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Materials and Environment","","",""
"uuid:bb1a678c-832d-45ec-afeb-49b273783495","http://resolver.tudelft.nl/uuid:bb1a678c-832d-45ec-afeb-49b273783495","Feedback Effects of Sediment Suspensions on Transport Mechanisms in an Estuarine Turbidity Maximum","Zhu, C. (TU Delft Coastal Engineering; Shanghai Estuarine and Coastal Science Research Center); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Shanghai Estuarine and Coastal Science Research Center; Deltares); Guo, Leicheng (Shanghai Estuarine and Coastal Science Research Center); Lin, J. (TU Delft Coastal Engineering; Shanghai Estuarine and Coastal Science Research Center); He, Qing (Shanghai Estuarine and Coastal Science Research Center); Wang, Zhengbing (TU Delft Coastal Engineering; Shanghai Estuarine and Coastal Science Research Center; Deltares)","","2022","The mechanisms controlling the formation of an estuarine turbidity maximum (ETM) in estuaries have been extensively investigated, but one aspect that has received much less scientific attention is the role of high suspended sediment concentrations in combination with tidal asymmetry in ETM formation. Particularly in highly turbid estuaries, sediment suspensions influence ETM development through a combination of horizontal sediment-induced density currents, a reduction in turbulent mixing, and water-bed exchange processes. In this study, we developed a schematic model resembling the Yangtze Estuary where the ETM is controlled by tidal pumping, estuarine circulation, and advection operating simultaneously. Model results suggest that high water slack tide asymmetry with Sediment-induced density effects (SedDE) favors landward migration of the ETM. In addition, without SedDE, stronger flood tidal dominance leads to more pronounced sediment trapping through tidal pumping. Depending on the type of tidal asymmetry, SedDE strengthen ETM growth by increasing estuarine circulation but may also lead to increased or reduced sediment concentration in the ETM due to enhanced or weakened landward tidal pumping, respectively. Higher near-bed sediment concentrations as a result of water-bed exchange processes, in turn, strengthen the effect of estuarine circulation but simultaneously strengthen the divergence of sediment by tidal pumping. Overall, the SedDE and higher near-bed sediment concentration, in combination with tidal asymmetry, play an important role in ETM formation and should be properly accounted for in studies on ETM dynamics in turbid estuaries.","estuarine circulation; estuarine turbidity maximum; fine sediments; tidal asymmetry; tidal pumping; water-bed exchange","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-12-02","","","Coastal Engineering","","",""
"uuid:007c7e1c-561c-4d67-8c35-03c0c29653c5","http://resolver.tudelft.nl/uuid:007c7e1c-561c-4d67-8c35-03c0c29653c5","Estimating loss of life caused by dam breaches based on the simulation of floods routing and evacuation potential of population at risk","Ge, Wei (Zhengzhou University); Jiao, Yutie (Zhengzhou University); Wu, Meimei (Henan University of Technology, Zhengzhou); Li, Zongkun (Zhengzhou University); Wang, Te (Zhengzhou University); Li, Wei (Zhengzhou Railway Vocational and Technical College); Zhang, Yadong (Zhengzhou University); Gao, Weixing (Zhengzhou University); van Gelder, P.H.A.J.M. (TU Delft Safety and Security Science)","","2022","Dam breaches often have catastrophic consequences in downstream areas. Hydrodynamic factors and the evacuation potential of the population at risk (PAR) have significant impacts on the loss of life (LOL) caused by dam breaches. However, the existing comprehensive evaluation models have not conducted in-depth research on the evacuation potential of populations. Thus, limited guidance is available for relevant departments to formulate emergency plans to reduce the potential LOL. Therefore, a new comprehensive evaluation model was proposed in this study. According to the relevant references and disaster theory, the main influencing factors and the process through which the LOL is caused by dam breaches were determined. The specific occurrence process was divided into six stages: a dam breach causes flood, the flood puts the PAR, the PAR complete the preparation work, the PAR evacuate, the un-evacuated population shelter themselves inside buildings, and flood causes the death of the exposed population. To calculate the LOL, the parameters relevant at each stage were defined. Furthermore, the Hydrologic Engineering Center's River Analysis System, Geographic Information System, and related materials were used to simulate the flood routing and evacuation potential of the PAR, quantifying the parameters in the model. The model was applied to 14 towns in the downstream areas of the Luhun Reservoir in Henan Province, China, and its accuracy was verified by comparing the results obtained from the two existing models. In addition, the specific suggestions for reducing the potential LOL were proposed based on the results of the simulation.","Dam breach; Disaster-causing mechanism; Emergency plan; Evacuation potential; Loss of life","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Safety and Security Science","","",""
"uuid:dc53d6f3-fee3-4f92-aa77-23d1ca3c99f3","http://resolver.tudelft.nl/uuid:dc53d6f3-fee3-4f92-aa77-23d1ca3c99f3","Micro-nano bubbles assisted laccase for biocatalytic degradation of bisphenols","Zhang, Jie (Chongqing Technology and Business University); Tan, Lirong (Chongqing Technology and Business University); Hagedoorn, P.L. (TU Delft BT/Biocatalysis); Wang, Ruiqi (Chongqing Technology and Business University); Wen, Li (Chongqing Technology and Business University); Wu, Siwei (Chongqing Technology and Business University); Tan, Xuemei (Chongqing Technology and Business University); Xu, Hui (Chongqing Technology and Business University); Zhou, Xing (Chongqing Academy of Chinese Materia Medica, Chongqing)","","2022","Bisphenols are important industrial materials for example for the production of plastics, but are also well known for their adverse health effects, in particular bisphenol A (BPA) is an endocrine disruptor. The widespread use of plastics has raised concerns. Therefore, the removal of bisphenols from wastewater has sparked the interest of the scientific community. This work introduces a novel hybrid technique of micro-nano bubbles assisted laccase (MNB-Lac) to degrade bisphenols in water. The feasibility of MNB-Lac using BPA as a model contaminant was evaluated by comparing with MNB, Lac, ultrasound (UL), UL-Lac, and UL-MNB-Lac. Comprehensive investigations were carried out to understand the specific influences of key process parameters including the initial pollutant concentration, temperature, air intake, pH, outlet pipe length, and Lac concentration on BPA degradation. The alkaline environment and extended length of outlet pipe could improve the degradation efficiency further. MNB-Lac exhibited 2.3–6.2 folds higher BPA degradation and less time than the other above process under the optimal parameters. The mechanism of MNB-Lac revealed that the generation of hydroxyl radical, high O2 solubility, and high mass transfer efficiency induced by MNB play important roles on enhancing the degradation catalyzed by Lac. MNB-Lac was successfully used for treating bisphenol B, bisphenol C, and the mixture of three bisphenols with high removal efficiency. Subsequently, these degradation products were analyzed by GC–MS. MNB-Lac potentially represents an innovative technology with considerable advantages in contaminant cleanup and time efficiency for treating phenolic contaminated water. Furthermore, the findings provide new insights into the enhancement of the performance of an oxidizing enzyme by introducing MNB technology.","Bisphenol; Degradation; Hydroxyl radical; Laccase; Micro-nano bubbles","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","BT/Biocatalysis","","",""
"uuid:a945dc4c-07cc-41ee-a70a-ad65d05bd343","http://resolver.tudelft.nl/uuid:a945dc4c-07cc-41ee-a70a-ad65d05bd343","Barrier Lyapunov function-based fixed-time FTC for high-order nonlinear systems with predefined tracking accuracy","Wang, Xiaolin (Air Force Engineering University China); Xu, Jihui (Air Force Engineering University China); Lv, Maolong (Air Traffic Control and Navigation College; Air Force Engineering University China; College of Aeronautics Engineering); Zhang, Lei (Air Force Engineering University China); Zhao, Z. (TU Delft Data-Intensive Systems)","","2022","This article proposes a fixed-time adaptive fault-tolerant control methodology for a larger class of high-order (powers are positive odd integers) nonlinear systems subject to asymmetric time-varying state constraints and actuator faults. In contrast with the state-of-the-art control methodologies, the distinguishing features of this study lie in that: (a) high-order asymmetric time-varying tan-type barrier Lyapunov function (BLF) is devised such that the state variables can be convergent to the preassigned compact sets all the time provided their initial values remain therein, which not only preserves the constraints satisfaction, but warrants the validity of the adopted neural network approximator; (b) the proposed control design ensures the tracking errors converge to specified residual sets within fixed time and makes the size of the convergence regions of tracking errors adjustable a priori by means of a new BLF-based tuning function and a projection operator; (c) a variable-separable lemma is delicately embedded into the control design to extract the control terms in a “linear-like” fashion which not only overcomes the difficulty that virtual control signals appear in a non-affine manner, but also solves the problem of actuator faults. Comparative simulations results finally validate the effectiveness of the proposed scheme.","Fixed-time stability; High-order nonlinear systems; High-order tan-type BLF; Predefined tracking accuracy","en","journal article","","","","","","","","","","","Data-Intensive Systems","","",""
"uuid:4eb27dae-1f14-4116-9645-ee67e6d17493","http://resolver.tudelft.nl/uuid:4eb27dae-1f14-4116-9645-ee67e6d17493","Impact damage of composite laminates with high-speed waterjet","Hou, Naidan (Northwestern Polytechnical University; Shaanxi Key Laboratory of Impact Dynamics and Its Engineering Application); Zhao, Renxi (Northwestern Polytechnical University; Shaanxi Key Laboratory of Impact Dynamics and Its Engineering Application); Li, Jian (School of Aeronautics; Northwestern Polytechnical University; Shaanxi Key Laboratory of Impact Dynamics and Its Engineering Application); Wang, Xuan (School of Aeronautics; Northwestern Polytechnical University; Shaanxi Key Laboratory of Impact Dynamics and Its Engineering Application); Li, X. (TU Delft Structural Integrity & Composites); Cui, Hao (School of Civil Aviation; Northwestern Polytechnical University; NPU Yangzi River Delta Research Institute); Li, Yulong (Shaanxi Key Laboratory of Impact Dynamics and Its Engineering Application; Northwestern Polytechnical University; NPU Yangzi River Delta Research Institute)","","2022","Rain erosion may cause substantial damage to aircrafts during supersonic flight. Such event is investigated here via high-speed waterjet impact on composite laminates. An experimental setup is developed to produce waterjets with the speed up to 700m/s and a finite element model of the waterjet-composite impact event is established. The consistency of experiment and simulation results validates the adopted numerical methods. The distribution of the water-hammer pressure is non-uniform and the maximum pressure occurs near the contact periphery when the water is about to eject laterally. After a high-speed (300∼560m/s) waterjet impacts a composite laminate, the impacted surface depression is observed, and the typical surface damage presents a central region with no visible surface damage surrounded by a faded “failure ring” with resin removal, matrix cracking and minor fiber fracture. Delamination occurs at the interfaces of adjacent layers with unequal dimensions and longitudinal matrix cracking appears on the back surface. Both the velocity and the diameter of waterjets are crucial factors on CFRP damage extents. Water-hammer pressure, the stagnation pressure and propagation of stress waves are failure mechanisms for most matrix damage in CFRP impacted by waterjets.","CFRP; Damage mechanics; Finite element analysis; Liquid impact; Water-hammer pressure","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Structural Integrity & Composites","","",""
"uuid:60d2c929-ded9-489c-9ff8-40c70cf97fd8","http://resolver.tudelft.nl/uuid:60d2c929-ded9-489c-9ff8-40c70cf97fd8","Wave Breaking Induced by Opposing Currents in Submerged Vegetation Canopies","Hu, Z. (Sun Yat-sen University; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering; Ministry of Education Hangzhou); Lian, S. (State Oceanic Administration China); Zitman, T.J. (TU Delft Coastal Engineering); Wang, H. (Sun Yat-sen University); He, Z. (Sun Yat-sen University; Ministry of Education Hangzhou); Wei, H. (Sun Yat-sen University; The Hong Kong University of Science and Technology); Ren, L. (Sun Yat-sen University); Uijttewaal, W.S.J. (TU Delft Environmental Fluid Mechanics); Suzuki, T. (TU Delft Environmental Fluid Mechanics; Flanders Hydraulics Research)","","2022","Wave height attenuation in vegetation canopies is often all attributed to the drag force exerted by vegetation, whereas other potential dissipation process is often neglected. Previous studies without vegetation have found that opposing currents can induce wave breaking and greatly increase dissipation. It is not clear if similar process may also occur in vegetation canopies. We conducted systematic flume experiments to show that wave breaking in opposing currents can occur in vegetated flows, but only in submerged canopies with shear currents above vegetation top. Subsequently, we developed a new analytical model to understand and assess the contribution of both drag-induced dissipation in the lower vegetation layer and current-induced breaking in the upper free layer. A new generic drag coefficient relation was applied in the model to quantify drag-induced dissipation with various current-wave combinations. It shows that breaking induced by opposing currents constitutes an essential part (up to 87%) of the total dissipation, which leads to considerably higher dissipation than the cases with following currents. Breaking can occur with various submergence ratios and with small opposing currents in the submerged vegetation field. It indicates that similar breaking process is likely to occur in real vegetation fields. The present study reveals and quantifies the current-induced wave breaking process that has not been reported before, which can improve our understanding of vegetation wave dissipation capacity in field conditions.","drag coefficient; flume; mangroves; wave breaking; wave dissipation; wave-current interactions","en","journal article","","","","","","","","2022-09-22","","","Coastal Engineering","","",""
"uuid:5d3deaf2-647a-4f3d-b27a-608c47a4f911","http://resolver.tudelft.nl/uuid:5d3deaf2-647a-4f3d-b27a-608c47a4f911","In vivo non-invasive confocal fluorescence imaging beyond 1,700 nm using superconducting nanowire single-photon detectors","Wang, Feifei (Stanford University); Ren, Fuqiang (Stanford University); Ma, Zhuoran (Stanford University); Qu, Liangqiong (Stanford University); Gourgues, Ronan (Single Quantum); Esmaeil Zadeh, I.Z. (TU Delft ImPhys/Optics); Los, Johannes W.N. (Single Quantum); Qin-Dregely, Y. (Single Quantum); Dai, Hongjie (Stanford University)","","2022","Light scattering by biological tissues sets a limit to the penetration depth of high-resolution optical microscopy imaging of live mammals in vivo. An effective approach to reduce light scattering and increase imaging depth is to extend the excitation and emission wavelengths to the second near-infrared window (NIR-II) at >1,000 nm, also called the short-wavelength infrared window. Here we show biocompatible core–shell lead sulfide/cadmium sulfide quantum dots emitting at ~1,880 nm and superconducting nanowire single-photon detectors for single-photon detection up to 2,000 nm, enabling a one-photon excitation fluorescence imaging window in the 1,700–2,000 nm (NIR-IIc) range with 1,650 nm excitation—the longest one-photon excitation and emission for in vivo mouse imaging so far. Confocal fluorescence imaging in NIR-IIc reached an imaging depth of ~1,100 μm through an intact mouse head, and enabled non-invasive cellular-resolution imaging in the inguinal lymph nodes of mice without any surgery. We achieve in vivo molecular imaging of high endothelial venules with diameters as small as ~6.6 μm, as well as CD169 + macrophages and CD3 + T cells in the lymph nodes, opening the possibility of non-invasive intravital imaging of immune trafficking in lymph nodes at the single-cell/vessel-level longitudinally.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","ImPhys/Optics","","",""
"uuid:a32cf0fc-92cb-42c5-8581-4eb240c10930","http://resolver.tudelft.nl/uuid:a32cf0fc-92cb-42c5-8581-4eb240c10930","Negative Effects of Inorganic Salt Invasion on the Dissociation Kinetics of Silica-Confined Gas Hydrate via Thermal Stimulation","Fang, B. (TU Delft Engineering Thermodynamics; China University of Geosciences, Wuhan); Lu, T. (China University of Geosciences, Wuhan; Hubei Key Laboratory of Advanced Control and Intelligent Automation for Complex Systems,); Cheng, Liwei (China University of Geosciences, Wuhan); Wang, Dongdong (China University of Geosciences, Wuhan); Ni, Yang (China University of Geosciences, Wuhan); Fan, Bowen (China University of Geosciences, Wuhan); Meng, Jiuling (China University of Geosciences, Wuhan); Vlugt, T.J.H. (TU Delft Engineering Thermodynamics); Ning, Fulong (China University of Geosciences, Wuhan; Qingdao National Laboratory for Marine Science and Technology)","","2022","Methane hydrate dissociation kinetics can be inhibited in NaCl solutions; however, this effect is reversed by promoting bubble formation that enhances dissociation. The negative and positive effects of inorganic salt injection on gas production from hydrate-bearing sediments are still controversial. Here, molecular dynamics simulations were performed to investigate the characteristics of NaCl solution invasion into hydrate-occupied nanopores and the effects on the confined hydrate dissociation kinetics. Two initial configurations comprising liquid and silica pore phases were studied with a low or high NaCl concentration, respectively. The results show that, under the simulation conditions, salt invasion decelerated hydrate dissociation within the silica pore as NaCl invasion into the pore is stepwise. Initially, few ions can diffuse into the pore phase, and gas nanobubbles form on the solid surface mainly via confinement and surface effects, independent of NaCl solution invasion. Subsequently, gradual salt diffusion immersed the residual hydrate in the salt solution and hindered hydrate decomposition until the dissociation finished. More ions could diffuse into the pore phase at the high NaCl concentrations with a low diffusion efficiency, leading to surface nanobubble growth toward the residual hydrate and somewhat accelerated hydrate dissociation. This severely hinders the escape of released methane from the pore. This study yields molecular-level insight into the origin of the negative effect of salt invasion on hydrate dissociation, which should be avoided during gas production from hydrate reservoirs with low permeabilities via salt injection combined with thermal stimulation.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Engineering Thermodynamics","","",""
"uuid:e47b21dc-961a-4a88-95e8-d5ab74a206b0","http://resolver.tudelft.nl/uuid:e47b21dc-961a-4a88-95e8-d5ab74a206b0","Trust in Institutions, Not in Political Leaders, Determines Compliance in COVID-19 Prevention Measures within Societies across the Globe","Badman, Ryan P. (RIKEN); Wang, Ace X. (State University of New York); Skrodzki, M. (TU Delft Computer Graphics and Visualisation; RIKEN); Cho, Heng-Chin (Academia Sinica); Aguilar-Lleyda, David (RIKEN); Shiono, Naoko (RIKEN); Yoo, Seng Bum Michael (Institute for Basic Science; Sungkyunkwan University); Chiang, Yen-Sheng (Academia Sinica); Akaishi, Rei (RIKEN)","","2022","A core assumption often heard in public health discourse is that increasing trust in national political leaders is essential for securing public health compliance during crises such as the COVID-19 pandemic (2019–ongoing). However, studies of national government trust are typically too coarse-grained to differentiate between trust in institutions versus more interpersonal trust in political leaders. Here, we present multiscale trust measurements for twelve countries and territories across the West, Oceania and East Asia. These trust results were used to identify which specific domains of government and social trust were most crucial for securing public health compliance (frequency of mask wearing and social distancing) and understanding the reasons for following health measures (belief in effectiveness of public health measures). Through the use of linear regression and structural equation modeling, our cross-cultural survey-based analysis (N = 3369 subjects) revealed that higher trust in national and local public health institutions was a universally consistent predictor of public health compliance, while trust in national political leaders was not predictive of compliance across cultures and geographical regions. Institutional trust was mediated by multiple types of transparency, including providing rationale, securing public feedback, and honestly expressing uncertainty. These results highlight the importance of distinguishing between components of government trust, to better understand which entities the public gives the most attention to during crises.","COVID-19; institutional trust; political trust; public health compliance; social trust; transparency","en","journal article","","","","","","","","","","","Computer Graphics and Visualisation","","",""
"uuid:c2d15bc9-93ab-4978-9d1c-76441302c247","http://resolver.tudelft.nl/uuid:c2d15bc9-93ab-4978-9d1c-76441302c247","Guanidium-assisted crystallization engineering for highly efficient CsPbI3 solar cells","Wang, Shuo (Lanzhou University); Xu, Youkui (Lanzhou University); Wang, Qian (Lanzhou University); Zhou, Xufeng (Liaocheng University); Li, ZhenHua (Lanzhou University); Wang, Meng (Lanzhou University); Lei, Yutian (Lanzhou University); Zhang, Hong (Lanzhou University); Wang, H. (TU Delft Photovoltaic Materials and Devices); Jin, Zhiwen (Lanzhou University)","","2022","Iodine vacancies and uncoordinated iodide ions of CsPbI3 films are mainly responsible for nonradiative recombination. Here, we report a composition-engineering passivation method that through guanidium (GA+) and I− forms strong hydrogen bonds to passivate iodine vacancies and reduce defects. Both experimental and theoretical results confirmed strong chemical interactions between GA+ and uncoordinated I− in the GAxCs1−xPbI3 bulk or at the grain boundary. Moreover, GA+ doping could slow down the crystallization speed of perovskite films during the deposition process. As a result, we observed GA+ modified films with much lower defect density, larger grain size, and better carrier extraction and transportation. Upon GA+ passivation, the power conversion efficiency (PCE) is boosted from 18.01% to 19.05%, with open-circuit voltage (VOC) enhancement from 1.08 V to 1.14 V.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-10-25","","","Photovoltaic Materials and Devices","","",""
"uuid:1854657d-07a8-44eb-a991-876370b0d456","http://resolver.tudelft.nl/uuid:1854657d-07a8-44eb-a991-876370b0d456","Effect of High Content of Waste Tire Rubber and Sulfur on the Aging Behavior of Bitumen","Wang, Sheng (Tongji University); Huang, Weidong (Tongji University); Liu, X. (TU Delft Pavement Engineering); Lin, P. (TU Delft Pavement Engineering); Ren, S. (TU Delft Pavement Engineering); Li, Yi (The Hong Kong Polytechnic University)","","2022","High content rubber modified bitumen (HCRMB) prepared from the high content of waste tire rubber and bitumen has good performance while allowing greater use of the waste tires. However, HCRMB is subject to aging during use, which can affect its performance. The purpose of this paper was to investigate the effect of high content of waste tire rubber and sulfur on the aging behavior of bitumen. The properties of all bitumen were tested using rolling thin film oven aging (RTFOT) test, pressure aging vessel (PAV) test, frequency sweep tests, temperature sweep (TS) test, multiple stress creep recovery (MSCR) test, and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) test. Test results show that the addition of sulfur to HCRMB leads to an improvement in the elasticity of HCRMB. The elasticity of HCRMB with different amounts of sulfur increases with aging. In addition, the increase in the amount of sulfur can improve the RTFOT aging resistance and the PAV aging resistance of HCRMB. Sulfur cannot reduce the degree of oxidation of HCRMB after aging, but can inhibit the degree of desulfurization of HCRMB. Furthermore, the aging process of HCRMB with different amounts of sulfur is dominated by the degradation of polybutadiene.","aging resistance; ATR-FTIR; frequency sweep tests; high content rubber modified bitumen; sulfur","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:ab7c6263-38a8-4cc6-b28c-b20cc198062b","http://resolver.tudelft.nl/uuid:ab7c6263-38a8-4cc6-b28c-b20cc198062b","A Novel Multiple-Ring Aromatic Spacer Based 2D Ruddlesden–Popper CsPbI3 Solar Cell with Record Efficiency Beyond 16%","Yao, Huanhuan (Lanzhou University); Li, Zhizai (Lanzhou University); Shi, Chang (Lanzhou University); Xu, Youkui (Lanzhou University); Wang, Qian (Lanzhou University); Li, Zhen Hua (Lanzhou University); Peng, Guoqiang (Lanzhou University); Lei, Yutian (Lanzhou University); Wang, H. (TU Delft Photovoltaic Materials and Devices)","","2022","Two-dimensional (2D) Ruddlesden–Popper (RP) CsPbI3 perovskite possesses superior phase stability by introducing steric hindrance. However, due to the quantum and dielectric confinement effect, 2D structures usually exhibit large exciton binding energy, and the charge tunneling barrier across the organic interlayer is difficult to eliminate, resulting in poor charge transport and performance. Here, a multiple-ring aromatic ammonium, 1-naphthylamine (1-NA) spacer is developed for 2D RP CsPbI3 perovskite solar cell (PSC). Theoretical simulations and experimental characterizations demonstrate that the 2D RP CsPbI3 perovskite using 1-NA spacer with extended π-conjugation lengths reduces the exciton binding energy and facilitates the efficient separation of excitons. In addition, its cations have a significant contribution to the conduction band, which can reduce the bandgap, promote electronic coupling between organic and inorganic layers, and improve interlayer charge transport. Importantly, the strong π–π conjugation of 1-NA spacer can enhance intermolecular interactions and hydrogen bonding, and prepare high-quality films with preferred vertical orientation, resulting in lower defect density, and directional charge transport. As a result, the (1-NA)2(Cs)3Pb4I13 PSC exhibits a record 16.62% performance with enhanced stability. This work provides an efficient approach to improve charge transport and device performance by developing multiple-ring aromatic spacers.","charge transport; exciton binding energy; Extended π-conjugation lengths; vertical orientations","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-01-01","","","Photovoltaic Materials and Devices","","",""
"uuid:a18267d7-1894-40e7-9997-19154b2f525c","http://resolver.tudelft.nl/uuid:a18267d7-1894-40e7-9997-19154b2f525c","Reclamation of Tidal Flats Within Tidal Basins Alters Centennial Morphodynamic Adaptation to Sea-Level Rise","Guo, Leicheng (Shanghai Estuarine and Coastal Science Research Center); Zhu, C. (TU Delft Coastal Engineering; Shanghai Estuarine and Coastal Science Research Center); Xu, Fan (Shanghai Estuarine and Coastal Science Research Center); Xie, Weiming (Shanghai Estuarine and Coastal Science Research Center); van der Wegen, Mick (IHE Delft Institute for Water Education; Deltares); Townend, Ian (University of Southampton); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); He, Qing (Shanghai Estuarine and Coastal Science Research Center)","","2022","Reclamation of low-lying tidal flats and floodplains adjacent to present shorelines has been implemented worldwide for both coastal defense and development. While it is technically feasible to monitor the short-term impact of tidal flat embankments, it is challenging to identify long-term and cumulative morphodynamic impact, particularly considering centennial sea-level rise (SLR). In this study, we construct a process-based hydro-morphodynamic model for a schematized tidal basin and examine its morphodynamic evolution under the combined influence of SLR and tidal flat embankments. We see that rising sea levels lead to inundation of low-lying floodplains just above high water, creating new intertidal flats that mitigate the drowning impact of SLR. This mitigation effect is lost if the low-lying floodplains and tidal flats are reclaimed, preventing any shoreline migration under SLR. Removing a large portion of intertidal flats within the tidal basin induces significant changes in basin hypsometry and potentially, a reversal of flood/ebb dominance. The resulting hydro-morphodynamic impact of large-scale tidal flat embankment is more significant than SLR at a centennial time scale. This suggests a need for much greater management awareness regarding the cumulative impact of human activities. These findings imply that allowing lateral shoreline migration under SLR sustains tidal basin's inherent morphodynamic buffering capacity, whereas reclaiming tidal flats significantly alters hydro-morphodynamic adaptation at the decadal to centennial time scales. It highlights the importance of conserving low-lying floodplains and tidal flats in tide-dominated systems to counteract the drowning impact of SLR.","embankment; morphodynamic modeling; sea-level rise; tidal basin","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-12-17","","","Coastal Engineering","","",""
"uuid:470d0944-7409-4633-9e61-23092137c72d","http://resolver.tudelft.nl/uuid:470d0944-7409-4633-9e61-23092137c72d","On the use of transfer modeling to design new steels with excellent rotating bending fatigue resistance even in the case of very small calibration datasets","Wei, Xiaolu (Northeastern University); van der Zwaag, S. (TU Delft Novel Aerospace Materials); Jia, Zixi (Northeastern University); Wang, Chenchong (Northeastern University); Xu, W. (TU Delft Novel Aerospace Materials; Northeastern University)","","2022","In this research a machine learning model for predicting the rotating bending fatigue strength and the high-throughput design of fatigue resistant steels is proposed. In this transfer prediction framework, machine learning models are first trained to estimate tensile properties (yield strength, tensile strength and elongation) on the basis of composition and critical process conditions. Then, based on the predicted tensile properties, transfer models are trained to estimate fatigue strength. The results are compared with those of a similar model not having such a transfer layer. The transfer prediction framework shows high accuracy for fatigue strength prediction with a remarkably high tolerance to limitations in the amount of calibration data available for training. By combining the transfer prediction framework with evolutionary algorithms, a robust high-throughput alloy design model is achieved requiring only tens of fatigue data points to get a decent reliability. The newly designed steel showed the predicted high fatigue strength. The method as presented here might also be applicable to other alloy design challenges in which only a limited database for the property to be optimized is available.","Alloy design; Fatigue strength; Machine learning; Small sample problem; Transfer learning","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-01-02","","","Novel Aerospace Materials","","",""
"uuid:ded518a4-3538-4f0a-9a59-8e598bbc578e","http://resolver.tudelft.nl/uuid:ded518a4-3538-4f0a-9a59-8e598bbc578e","Automatic depression recognition by intelligent speech signal processing: A systematic survey","Wu, Pingping (Nanjing Audit University); Wang, Ruihao (Nanjing Audit University); Lin, Han (Nanjing Audit University); Zhang, Fanlong (Nanjing Audit University); Tu, Juan (Nanjing University); Sun, M. (TU Delft Signal Processing Systems)","","2022","Depression has become one of the most common mental illnesses in the world. For better prediction and diagnosis, methods of automatic depression recognition based on speech signal are constantly proposed and updated, with a transition from the early traditional methods based on hand-crafted features to the application of architectures of deep learning. This paper systematically and precisely outlines the most prominent and up-to-date research of automatic depression recognition by intelligent speech signal processing so far. Furthermore, methods for acoustic feature extraction, algorithms for classification and regression, as well as end to end deep models are investigated and analysed. Finally, general trends are summarised and key unresolved issues are identified to be considered in future studies of automatic speech depression recognition.","","en","review","","","","","","","","","","","Signal Processing Systems","","",""
"uuid:68c0cc39-bbcb-4bff-a336-e45bbb53fa39","http://resolver.tudelft.nl/uuid:68c0cc39-bbcb-4bff-a336-e45bbb53fa39","Periodic structures for melting enhancement: observation of critical cell size and localized melting","Zhao, Chunrong (University of Queensland); Opolot, Michael (University of Queensland); Liu, Ming (University of South Australia); Wang, Ji (University of South Australia); Bruno, Frank (University of South Australia); Mancin, Simone (Università degli Studi di Padova); Hooman, K. (TU Delft Process and Energy)","","2022","The use of metallic periodic structures was considered for melting rate enhancement of a phase change material (PCM) contained in a rectangular enclosure isothermally heated from the side. The critical (optimized) cell size, or pore size, of a periodic structure with fixed porosity, realising the shortest melting time by maximizing the convection and conduction heat transfer rate into the PCM, was studied. Furthermore, the effects of material properties (copper, aluminium, nickel, and stainless steel), enclosure length, wall-melting temperature difference and porosity were numerically investigated. It was observed that increasing porosity and/or reducing thermal conductivity enlarged the critical cell size (i.e. the optimal cell size that minimizes the melting time). The critical PPIs (pores per inch) of copper and aluminium periodic structures for all studied porosities were 10; for nickel, the critical values were 10 PPIs for porosity values of 0.75, 0.8 and 0.85 while it reduces to 5 PPI for the highest porosity considered here being 0.95. Interestingly, showing a different trend, the critical PPI of stainless-steel structures was 5 for the lowest porosity (0.75) and reduced to 3 for higher porosities. The results clearly demonstrated localised melting which was observed in all periodic structures except for the 10 PPI stainless-steel case. Scattered melting islands are observed as opposed to a moving interface when ϕ=(dp/L)αligament/αPCM>1. For such cases, localized melting occurs and the PCM is melted at the ligaments away from the heated wall before the melt front reaches those ligaments.","Critical cell size; PCM melting; Periodic structure","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-12-20","","Process and Energy","","","",""
"uuid:8017c584-6ea0-4538-9268-b23cb0af99ac","http://resolver.tudelft.nl/uuid:8017c584-6ea0-4538-9268-b23cb0af99ac","VLBI observations of VIK J2318-3113, a quasar at z = 6.44","Zhang, Y. (Ska Regional Centre Joint Lab; Chinese Academy of Sciences); An, T. (Chinese Academy of Sciences; Ska Regional Centre Joint Lab; University of Chinese Academy of Sciences); Wang, A. (Ska Regional Centre Joint Lab; Chinese Academy of Sciences; College of Astronomy and Space Sciences; University of Chinese Academy of Sciences); Frey, S. (Konkoly Observatory Hungarian Academy of Sciences; Eötvös University); Gurvits, L. (TU Delft Astrodynamics & Space Missions; Joint Institute for VLBI ERIC); Gabányi, K. E. (Konkoly Observatory Hungarian Academy of Sciences; Eötvös University); Perger, K. (Konkoly Observatory Hungarian Academy of Sciences); Paragi, Z. (Joint Institute for VLBI ERIC)","","2022","The nature of jets in active galactic nuclei (AGNs) in the early Universe and their feedback to the host galaxy remains a highly topical question. Observations of the radio structure of high-redshift AGNs enabled by very long baseline interferometry (VLBI) provide indispensable input into studies of their properties and role in the galaxies' evolution. To date, only five AGNs at redshift z 6 have been studied with the VLBI technique. Aims. VIK J2318-3113 is a recently discovered quasar at z = 6:44 that had not been imaged with VLBI before the current work. Here we present the first VLBI imaging results of this high-redshift quasar, with the aim of corroborating its high-resolution appearance with the physical model of the object. Methods. We carried out VLBI phase-referencing observations of VIK J2318-3113 using the Very Long Baseline Array at two frequencies, 1.6 and 4.7 GHz, and obtained the first view at the radio structure on the milliarcsecond scale. Results. The source was clearly detected at 1.6 GHz. We found that almost all of its radio emission comes from the parsec-scale core region. Our dual-frequency observations constrain the spectral index and brightness temperature of the radio core. Its properties are similar to those of other known high-redshift radio-loud AGNs.","Galaxies: high-redshift; Galaxies: jets; Quasars: general; Quasars: individual: VIK J2318-3113","en","journal article","","","","","","","","","","","Astrodynamics & Space Missions","","",""
"uuid:6e27a89b-6031-40be-8535-61bd5d4dbcf9","http://resolver.tudelft.nl/uuid:6e27a89b-6031-40be-8535-61bd5d4dbcf9","HRBF-Fusion: Accurate 3D Reconstruction from RGB-D Data Using On-the-fly Implicits","Xu, Yabin (Nanjing University of Aeronautics and Astronautics); Nan, L. (TU Delft Urban Data Science); Zhou, Laishui (Nanjing University of Aeronautics and Astronautics); Wang, Jun (Nanjing University of Aeronautics and Astronautics); Wang, C.C. (TU Delft Materials and Manufacturing; The University of Manchester)","","2022","Reconstruction of high-fidelity 3D objects or scenes is a fundamental research problem. Recent advances in RGB-D fusion have demonstrated the potential of producing 3D models from consumer-level RGB-D cameras. However, due to the discrete nature and limited resolution of their surface representations (e.g., point or voxel based), existing approaches suffer from the accumulation of errors in camera tracking and distortion in the reconstruction, which leads to an unsatisfactory 3D reconstruction. In this article, we present a method using on-the-fly implicits of Hermite Radial Basis Functions (HRBFs) as a continuous surface representation for camera tracking in an existing RGB-D fusion framework. Furthermore, curvature estimation and confidence evaluation are coherently derived from the inherent surface properties of the on-the-fly HRBF implicits, which are devoted to a data fusion with better quality. We argue that our continuous but on-the-fly surface representation can effectively mitigate the impact of noise with its robustness and constrain the reconstruction with inherent surface smoothness when being compared with discrete representations. Experimental results on various real-world and synthetic datasets demonstrate that our HRBF-fusion outperforms the state-of-the-art approaches in terms of tracking robustness and reconstruction accuracy.","3D reconstruction; camera tracking; closed-form HRBFs; fusion; registration","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright older of this work and the author uses the Dutch legislation to make this work public.","","2022-10-28","","","Urban Data Science","","",""
"uuid:9864c313-2e8a-4521-a624-dc956ef615fd","http://resolver.tudelft.nl/uuid:9864c313-2e8a-4521-a624-dc956ef615fd","EdgeTuner: Fast Scheduling Algorithm Tuning for Dynamic Edge-Cloud Workloads and Resources","Han, Rui (Beijing Institute of Technology); Wen, Shilin (Beijing Institute of Technology); Liu, Chi Harold; Yuan, Ye (Beijing Institute of Technology); Wang, Guoren (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Data-Intensive Systems)","","2022","Edge-cloud jobs are rapidly prevailing in many application domains, posing the challenge of using both resource-strenuous edge devices and elastic cloud resources. Efficient resource allocation on such jobs via scheduling algorithms is essential to guarantee their performance, e.g. latency. Deep reinforcement learning (DRL) is increasingly adopted to make scheduling decisions but faces the conundrum of achieving high rewards at a low training overhead. It is unknown if such a DRL can be applied to timely tune the scheduling algorithms that are adopted in response to fast changing workloads and resources. In this paper, we propose EdgeTuner to effectively leverage DRL to select scheduling algorithms online for edge-cloud jobs. The enabling features of EdgeTuner are sophisticated DRL model that captures complex dynamics of Edge-Cloud jobs/tasks and an effective simulator to emulate the response times of short-running jobs in accordance to dynamically changing scheduling algorithms. EdgeTuner trains DRL agents offline by directly interacting with the simulator. We implement EdgeTuner on Kubernetes scheduler and extensively evaluate it on Kubernetes cluster testbed driven by the production traces. Our results show that EdgeTuner outperforms prevailing scheduling algorithms by achieving significant lower job response time while accelerating DRL training speed by more than 180x.","DRL; Edge-cloud workloads; Kubernetes; run-time tuning; scheduling algorithm","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Data-Intensive Systems","","",""
"uuid:ae82ccb1-1a78-47c3-a2d0-2c86a9f15046","http://resolver.tudelft.nl/uuid:ae82ccb1-1a78-47c3-a2d0-2c86a9f15046","Dreaming the wrong dream: An exploratory case study of a policy change toward sustainable urban development in a medium-sized Chinese city","Song, Y. (TU Delft Organisation & Governance; Erasmus Universiteit Rotterdam); de Jong, W.M. (TU Delft Organisation & Governance; Erasmus Universiteit Rotterdam; Fudan University); Stead, D. (TU Delft Spatial Planning and Strategy; Aalto University); Yang, Wei (Northeastern University); Wang, B. (TU Delft Urban Development Management)","","2022","Sustainable urban transformation has become a mantra for Chinese cities. While most studies focus on sustainable urbanization in megacities, the far larger number of medium-sized cities is understudied, although the latter face more severe urban problems. This article develops a framework for examining policy change in sustainable urban development initiated at the central level and reactions, tensions, and implementation issues emerging at the local level. It focuses on an in-depth case study of the challenges in realizing a transition from quantity-oriented pro-growth policies to sustainable quality-oriented ones in a medium-sized Chinese city. We find that there is evidence of changes in long-term values and goals toward sustainability at the levels of both central and local government, but also great inconsistency between goals on paper and policy implementation in practice. Sustainability in urban development is much harder to realize as local officials see urban development as a major means to maintain local economic growth, which can be separated from other issues in ecological preservation. The article concludes with a roadmap for future studies focusing on medium-sized cities, especially indicating how narratives on sustainable urban development hide from view financial and environmental risks generated by the actual implementation of the dominant aggressive urban pro-growth model.","infrastructure development; medium-sized cities; Policy paradigm; sustainable urban transition; urban growth","en","journal article","","","","","","","","","","","Organisation & Governance","","",""
"uuid:8bf995b4-ad08-4e36-963d-7be4b193222e","http://resolver.tudelft.nl/uuid:8bf995b4-ad08-4e36-963d-7be4b193222e","Spin-Mixing Enhanced Proximity Effect in Aluminum-Based Superconductor–Semiconductor Hybrids","Mazur, G.P. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); van Loo, N. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); Wang, J. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); Dvir, T. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); Wang, Guanzhong (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); Korneychuk, S. (Kavli institute of nanoscience Delft); Borsoi, F. (TU Delft QCD/Veldhorst Lab; Kavli institute of nanoscience Delft); Dekker, R.C. (TU Delft QN/Steele Lab; Kavli institute of nanoscience Delft); Badawy, G.H.A. (Eindhoven University of Technology); Vinke, Peter (Student TU Delft; Kavli institute of nanoscience Delft); Quintero Perez, M. (TNO); Heedt, S. (TU Delft BUS/Quantum Delft; Kavli institute of nanoscience Delft); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; Kavli institute of nanoscience Delft)","","2022","In superconducting quantum circuits, aluminum is one of the most widely used materials. It is currently also the superconductor of choice for the development of topological qubits. However, aluminum-based devices suffer from poor magnetic field compatibility. Herein, this limitation is resolved by showing that adatoms of heavy elements (e.g., platinum) increase the critical field of thin aluminum films by more than a factor of two. Using tunnel junctions, it is shown that the increased field resilience originates from spin-orbit scattering introduced by Pt. This property is exploited in the context of the superconducting proximity effect in semiconductor–superconductor hybrids, where it is shown that InSb nanowires strongly coupled to Al/Pt films can maintain superconductivity up to 7 T. The two-electron charging effect is shown to be robust against the presence of heavy adatoms. Additionally, non-local spectroscopy is used in a three-terminal geometry to probe the bulk of hybrid devices, showing that it remains free of sub-gap states. Finally, it is demonstrated that proximitized semiconductor states maintain their ability to Zeeman-split in an applied magnetic field. Combined with the chemical stability and well-known fabrication routes of aluminum, Al/Pt emerges as the natural successor to Al-based systems and is a compelling alternative to other superconductors, whenever high-field resilience is required.","aluminum; high-magnetic-field; nanowires; superconductivity","en","journal article","","","","","","","","","","","QRD/Kouwenhoven Lab","","",""
"uuid:097afabf-c77e-49d5-a85e-f3e38b5a3647","http://resolver.tudelft.nl/uuid:097afabf-c77e-49d5-a85e-f3e38b5a3647","Creating coagulants through the combined use of ash and brine","Hao, Xiaodi (Beijing University of Civil Engineering & Architecture); Wang, Xiangyang (Beijing University of Civil Engineering & Architecture); Shi, Chen (Beijing University of Civil Engineering & Architecture); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology; Beijing University of Civil Engineering & Architecture); Wu, Yuanyuan (Beijing University of Civil Engineering & Architecture)","","2022","Sludge incineration and seawater desalination are two approaches that can be used in the disposal of waste activated sludge (WAS) and for obtaining fresh water. As resource recovery from wastewater treatment and water purification is a topic of particular interest in these times, “water mining” has become a focus of research, with phosphate/P-recovery from WAS incineration ash, and extraction of useful elements from the brine of desalination being important steps in the pursuit of a circular/blue economy. However, P-recovery from ash involves removing metals, which need to be disposed of carefully, as does the brine collected. If cations in the ash and anions in the brine could be combined in order to produce coagulants/flocculants, a new circular model would be established. A preliminary experiment for this purpose has demonstrated that a liquid poly‑aluminum chloride (PAC) could be synthesized from the aluminum ion/Al3+ removed from the ash and the original brine. With this work, we synthesized the liquid PAC by a hydrothermal method, and the results from infrared spectrometer demonstrated that the synthesized PAC was similar to a commercial PAC. Moreover, the synthesized PAC was able to efficiently reduce the effluent turbidity of wastewater treatment plants (WWTPs), especially when compared with the commercial PAC. It is therefore important that research in this area be continued in order to improve the quality of synthesized coagulants and to produce different coagulants based on cations and anions in ash and brine.","Brine; Coagulants; Desalination; Phosphorus recovery; Removing metals; Sludge incineration","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","BT/Environmental Biotechnology","","",""
"uuid:d7690b8b-79ff-4747-9460-31dbc58e405e","http://resolver.tudelft.nl/uuid:d7690b8b-79ff-4747-9460-31dbc58e405e","Microwave heating mechanism and Self-healing performance of scrap tire pyrolysis carbon black modified bitumen","Wang, Fu (Wuhan Institute of Technology); Zhu, Hongbin (Wuhan Institute of Technology); Li, Yuanyuan (Wuhan Institute of Technology); Gu, Dengjun (Wuhan Institute of Technology); Gao, Y. (TU Delft Pavement Engineering); Feng, Jianlin (Wuhan Institute of Technology); Shu, Benan (Foshan Transportation Science and Technology Co.); Li, Chao (Foshan Transportation Science and Technology Co.); Wu, Shaopeng (Wuhan University of Technology)","","2022","Conventional asphalt mixture has poor microwave absorbing performance and microwave heating efficiency. Based on the characteristics of dielectric loss of scrap tire pyrolysis carbon black (PCB), it is proposed to improve the microwave absorbing performance and self-healing rate of bitumen. The phase composition and electromagnetic parameters of PCB were tested to reveal its microwave heating mechanism. The preparation parameters, heating characteristics and self-healing properties of PCB modified bitumen were studied through the dispersion uniformity test, microwave heating test and SCB test. The main phases of PCB are microwave absorbing carbon and silicon, indicating that PCB is a good electric loss microwave absorbing material. 40 min is the recommended mixing time of 15% PCB modified bitumen. PCB's dosage, microwave frequency and microwave heating time have significant effects on the microwave heating characteristics of PCB modified bitumen. PCB can improve high-temperature stability, thermal conductance, heat storage capacity and self-healing rate of bitumen.","Bitumen; Heating characteristics; Microwave heating mechanism; Scrap tire pyrolysis carbon black (PCB); Self-healing performance","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Pavement Engineering","","",""
"uuid:32257460-42c8-4f3b-8874-9de931e7351b","http://resolver.tudelft.nl/uuid:32257460-42c8-4f3b-8874-9de931e7351b","Resource Allocation Equity in the China’s Rural Three-Tier Healthcare System","Ao, Yibin (Chengdu University of Technology); Feng, Qiqi (Chengdu University of Technology); Zhou, Zhongli (Chengdu University of Technology); Chen, Yunfeng (Purdue University); Wang, T. (TU Delft Design & Construction Management)","","2022","The rural three-tier healthcare system is an essential part of the Chinese healthcare service system. To ensure rural residents’ equal access to such healthcare services, it is necessary to examine the current status of the healthcare system in rural China and formulate corresponding improvement suggestions. This study therefore collects the data from the China Health Statistics Yearbook, the China Health Yearbook and the China Statistical Yearbook between the years 2004 and 2021 to calculate the Gini coefficient (G), health resource density index (HRDI) and Theil index (T) first, and then perform the Mann–Kendall test afterwards to evaluate the equity of healthcare resource allocation comprehensively. This series of analysis helps in drawing the following conclusions: (1) county and county-level city medical and health institutions (CMHIs) show a higher development trend in comparison with township hospitals (THs) and village clinics (VCs); (2) VCs have higher institutional fairness, while for beds and personnel, CMHIs and THs are more fairly positioned; (3) more specifically for CMHIs and THs, personnel allocation is more fair than beds and institution allocations; (4) the density of healthcare resources in the eastern and central regions is higher than that in the western part, while the intra-regional distribution of beds and personnel in the west and central regions is better than that in the eastern region; (5) intra-regional differences are more significant than inter-regional differences and the fairness according to population distribution is higher than that of geographical area allocation. The results of this study provide theoretical basis for further optimizing the allocation of healthcare resources and improving the fairness of healthcare resources allocation from a macro perspective.","equity; resource allocation; rural China; three-tier healthcare system","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:10b85d45-d3dd-4ec1-b9d2-3f4d37663c7a","http://resolver.tudelft.nl/uuid:10b85d45-d3dd-4ec1-b9d2-3f4d37663c7a","O3HSC: Outsourced Online/Offline Hybrid Signcryption for Wireless Body Area Networks","Liu, Suhui (Southeast University); Chen, Liquan (Southeast University); Wang, Huaqun (Nanjing University of Posts and Telecommunications); Fu, S. (TU Delft Cyber Security); Shi, Lin (Southeast University)","","2022","Wireless body area networks (WBAN) enable ubiquitous monitoring of patients, which can change the future of healthcare services overwhelmingly. As the collected data of patients usually contain sensitive information, how to collect, transfer, store and share data securely and properly has become a concerning issue. Attribute-based encryption (ABE) can achieve data confidentiality and fine-grained access control simultaneously. Identity-based ring signature (IBRS) allows patients to prove their identity without leaking any extra (private) information. However, the heavy computational burden of ABE and IBRS is intolerable for most power-limited mobile devices, which account for a large proportion of WBAN devices. This paper combines the attribute-based online/offline encryption (ABOOE) and IBRS to achieve an outsourced online/offline hybrid signcryption ( O3 HSC) scheme. As far as we know, this scheme is the first signcryption scheme that adopts IBRS and satisfies online/offline signcryption simultaneously. O3 HSC divides the key generation and signcryption into offline and online phases to increase the throughput of the central authority and save the power resources of mobile devices, respectively. Besides, outsourced decryption and public signature verification are also realized. O3 HSC achieves security under CCA and CMIA, and the performance analysis shows that O3 HSC is a lightweight and applicable scheme for WBAN.","Attribute-based online/offline encryption; identity-based ring signature; outsourced decryption; wireless body area network","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Cyber Security","","",""
"uuid:a2bd0f0c-46a0-4f2f-a643-3ce4ba67d32d","http://resolver.tudelft.nl/uuid:a2bd0f0c-46a0-4f2f-a643-3ce4ba67d32d","A neural network-assisted 3D theoretical thermoelastic solution for laminated liquid crystal elastomer plate used in restoring cardiac mechanical function","Wang, Jue (Hohai University); Yuan, Weiyi (Hohai University); Li, Z. (TU Delft Electronic Components, Technology and Materials); Trofimov, Yuri (Center of LED and Optoelectronic Technologies of NAS Belarus, Minsk); Lishik, Sergey (Center of LED and Optoelectronic Technologies of NAS Belarus, Minsk); Fan, J. (TU Delft Electronic Components, Technology and Materials; Fudan University; Chinese Academy of Sciences; Fudan Zhangjiang Institute,)","","2022","Some atrial contractile assist devices applied on the heart surface can be regarded as a laminated Liquid crystal elastomer (LCE) plate under steady temperature loads and a contact mechanical force. An exact solution for the deformation of the laminated LCE plate under combined thermal and mechanical loads is derived by solving the three-dimensional (3D) equilibrium equations including heat conduction and thermoelastic theory. The validity of mathematical formula and computer programming is proved by convergence and comparison examples with finite element method (FEM). In order to simplify the complex calculation of exact solution, a back propagation neural network (BPNN) is further trained with a database containing 9504 sets of thermo-mechanical load conditions and their corresponding deformation which is solved by the exact solutions. Then the deformations of LCE plate subject to combined thermo-mechanical load can be predicted by this BP neural network instead of complex numerical calculation. Moreover, it is also applied to inverse the contact mechanical force at the bottom surface of LCE plate with a given deformation and temperature conditions. The results show that: (1) The results from the exact theoretical solution are in consistence with that from FEM but have a higher computational efficiency and stability; (2) The deformation of the laminated plate is more sensitive to the layered thickness of LCE than the variation of the temperature; (3) 3-D elasticity solutions of a laminated LCE plate under the combined thermos-mechanical load can be effectively predicted by a trained BP neural network.","Exact solution; Laminated plate; Liquid crystal elastomer; Neural network; Thermoelastic theory","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Components, Technology and Materials","","",""
"uuid:448b28ec-e2c4-4613-8aa1-6b6b3f55dcf9","http://resolver.tudelft.nl/uuid:448b28ec-e2c4-4613-8aa1-6b6b3f55dcf9","Monitoring Yearly Change Patterns of the Surface Tidal Trail (STT) in Tidal Flats: A Novel Morphological Indicator Extracted from a Near-Infrared Terrestrial Laser Scanner","Zhan, Y.J. (TU Delft Coastal Engineering; Shanghai Estuarine and Coastal Science Research Center); Aarninkhof, S.G.J. (TU Delft Hydraulic Engineering); Wang, Zhengbing (TU Delft Coastal Engineering); Zhou, Yunxuan (Shanghai Estuarine and Coastal Science Research Center)","","2022","Tidal flats play an important role in the geomorphological and biological dynamics of coasts. Research on the morphological evolution of tidal flats constitutes one of the key research issues pertaining to the sustainability of coastal ecosystems and related coastal defense issues. In this work, a novel indicator, the surface tidal trail (STT), was extracted from a near infrared terrestrial laser scanner and studied. The results show that the area intensity and size of STTs decline yearly. Meanwhile, the position shift of the peak value on the STT curves presents a similar pattern of hydrodynamic force in response to the seawall, which has been studied in previous works. Although no direct correlation between the STT intensity and the deposition rate was found, the corresponding hydrodynamic force data were not available in this work. The change process of STTs still provides a possible speculation that hydrodynamic force and the softness of tidal surfaces are two main factors that form and influence STTs. For future research, establishing the direct quantitative relationships among hydrodynamic force, topography, and STTs on different temporal and spatial scales would help to better understand this novel indicator.","fine-scale; micro topography; Seawall; surface moisture","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","Hydraulic Engineering","Coastal Engineering","","",""
"uuid:599ce3a1-f057-45f9-891d-3b256362b55c","http://resolver.tudelft.nl/uuid:599ce3a1-f057-45f9-891d-3b256362b55c","A comprehensive review on the prediction of ship energy consumption and pollution gas emissions","Wang, K. (TU Delft Transport Engineering and Logistics; Dalian Maritime University); Wang, Jianhang (Dalian Maritime University); Huang, Lianzhong (Dalian Maritime University); Yuan, Yupeng (University of Cambridge; MOST); Wu, Guitao (Dalian Maritime University); Xing, Hui (Dalian Maritime University); Wang, Zhongyi (Dalian Maritime University); Wang, Zhuang (Shanghai Jiao Tong University); Jiang, X. (TU Delft Transport Engineering and Logistics)","","2022","Ship energy consumption and emission prediction are critical for ship energy efficiency management and pollution gas emission control, both of which are major concerns for the shipping industry and hence continue to attract global attention and research interest. This article examined the energy efficiency data sources, big data analysis for energy efficiency, and analyzed the ship energy consumption and emission prediction models. The ship energy consumption and pollution gas emission prediction models are comprehensively summarized based on the modeling method and principles. The theoretical analysis and artificial intelligence-based ship energy consumption model, as well as the top-down and bottom-up ship emission prediction models, are thoroughly examined in terms of influencing factors, model accuracy, data sources, and practical applications. On this basis, the challenges of ship energy consumption and emission prediction are discussed, and future research suggestions are proposed, providing a foundation for the development of ship energy consumption and emission prediction technologies. The analysis results show that the principles, parameters of concern, and data quality all have a significant impact on the performance of the prediction models. Consequently, the prediction model's accuracy can be improved by combining intelligent algorithms and machine learning. In the future, high precision, self-adapting, ship fuel consumption and emission prediction models based on artificial intelligence technology should be further studied, in order to improve their prediction performance, and thus providing solid foundations for the optimization management and control of the ship energy consumption and emissions.","Artificial intelligence; Big data analysis; Energy consumption model; Energy efficiency optimization; Low-carbon shipping; Ship emission prediction","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-05-01","","","Transport Engineering and Logistics","","",""
"uuid:2b75cc88-a569-4d82-91ba-a62e7669cc25","http://resolver.tudelft.nl/uuid:2b75cc88-a569-4d82-91ba-a62e7669cc25","A Novel Unspecific Peroxygenase from Galatian marginata for Biocatalytic Oxyfunctionalization Reactions","Ma, Yunjian (South China University of Technology; Macau University of Science and Technology); Liang, Hongjing (South China University of Technology); Zhao, Zexin (Hubei University of Technology); Wu, Bin (South China University of Technology); Lan, Dongming (South China University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Yonghua (South China University of Technology; Guangdong Youmei Institute of Inteligent Bio-manufacturing Co, Guangdong)","","2022","Unspecific peroxygenases (UPOs, EC 1.11.2.1) are promising oxyfunctionalization catalysts because of their unique stereoselectivity. However, so far only a few UPOs have been reported. In this study, gene mining was used to identify a gene from Galerina marginata that coded for a novel UPO (GmaUPO). GmaUPO was expressed in Pichia pastoris X-33 by scale-up fermentation (the UPO activity of the culture supernatant was 118 U/L). GmaUPO exhibited a molecular weight of 40 kDa and exhibited highest activity at 35°C and pH 9, respectively. Furthermore, GmaUPO was demonstrated to catalyze the epoxidation, sulfoxidation, and hydroxylation of common substrates, particularly fatty acids such as tridecanoic acid. The molecular basis for GmaUPO regioselectivity for fatty acid hydroxylation was explored by molecular modelling. The regioselectivity was mostly governed by the architecture of the enzyme's active site.","Bioinformatics analysis; Galerina marginata; Heterologous expression; Oxyfunctionalization; Unspecific peroxygenase","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:03b30b9a-3100-4203-a286-33790726232d","http://resolver.tudelft.nl/uuid:03b30b9a-3100-4203-a286-33790726232d","A Weighted Surrogate Model for Spatio-Temporal Dynamics with Multiple Time Spans: Applications for the Pollutant Concentration of the Bai River","Huan, Y. (TU Delft Mathematical Physics; TU Delft Beijing Delft Institute of Intelligent Science and Technology); Tian, Yubin (Beijing Institute of Technology); Wang, Dianpeng (Beijing Institute of Technology)","","2022","Simulations are often used to investigate the flow structures and system dynamics of complex natural phenomena and systems, which are significantly harder to obtain from experiments or theoretical analyses. Surrogate models are employed to mimic the results of simulations by reducing computational costs. In order to reduce the amount of computational time consumed, a novel framework for building efficient surrogate models is proposed in this work. The novelty lies in that the new framework runs simulations using the different simulation time spans for different inputs and builds a comprehensive surrogate model through the fusion of non-homogeneous spatio-temporal data by integrating the temporal and spatial correlations in parametric space. This differs from the existing works in the literature, which only consider the situation of spatio-temporal data with a consistent time span during simulations under different inputs. Some simulation studies and real data analysis concerning the pollution of the river in the Sichuan Province of China are used to demonstrate the superior performance of the proposed methods.","cokriging; prediction; proper orthogonal decomposition; spatio-temporal data","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:cf2152af-a575-4c0d-aa5f-89bc0b1cee7f","http://resolver.tudelft.nl/uuid:cf2152af-a575-4c0d-aa5f-89bc0b1cee7f","Workshop on Multimodal Motion Sickness Detection and Mitigation Methods for Car Journeys","Pöhlmann, Katharina Margareta Theresa (University of Glasgow); Li, Gang (University of Glasgow); Dam, Abhraneil (Virginia Polytechnic Institute and State University); Wang, Yu Kai (University of Technology Sydney); Wei, Chun Shu (National Yang Ming Chiao Tung University, Hsinchu); Brietzke, Adrian (Volkswagen AG); Papaioannou, G. (TU Delft Intelligent Vehicles)","","2022","The mass adoption of automated vehicles in the near future will benefit safety (of occupants and pedestrians), the environment (low emissions), and society (accessibility, on-demand travel). There are, however, still challenges that need to be addressed, with one of the most crucial being motion sickness. In automated vehicles, the interior could be transformed into a living room or a working space, allowing occupants to spend their time with non-driving activities. These changes are likely to provoke, and increase, motion sickness incidence. To that end, this workshop will explore the current state of motion sickness detection and mitigation methods from different angles (e.g., closed-loop detection, multimodal motion cues,etc.) through expert talks and reflections, followed by discussions. The workshop will develop an agenda for motion sickness research in automated vehicles, facilitate new research ideas and fruitful collaborations.","Automated Vehicles; Comfort; Detection; Mitigation; Motion Sickness","en","conference paper","Association for Computing Machinery (ACM)","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Intelligent Vehicles","","",""
"uuid:99dc4a89-524a-4740-95f0-bf3af94012a9","http://resolver.tudelft.nl/uuid:99dc4a89-524a-4740-95f0-bf3af94012a9","An Interface Co-modification Strategy for Improving the Efficiency and Stability of CsPbI3Perovskite Solar Cells","Guan, Hui (Lanzhou University); Lei, Yutian (Lanzhou University); Wu, Qiyuan (Lanzhou University); Zhou, Xufeng (Liaocheng University); Wang, H. (TU Delft Photovoltaic Materials and Devices); Wang, Gang (Ningbo University); Li, Wenquan (Qinghai Normal University); Jin, Zhiwen (Lanzhou University); Lan, Wei (Lanzhou University)","","2022","Interface engineering is a simple and effective strategy for improving the photovoltaic performance and stability of perovskite solar cells (PSCs). Herein, an interface co-modification strategy is proposed, using [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and 2-fluoro-1,4-phenylenediammonium iodide (2FPPD) to modify the electron transport layer (ETL)/perovskite (PVK) and the PVK/hole transport layer (HTL) interfaces, respectively. A series of characterizations demonstrate that the PCBM&2FPPD interface co-modification strategy effectively enhances the extraction and transport efficiency of carriers at the interface, passivates surface defects, inhibits the nonradiative recombination of carriers, and simultaneously inhibits ion migration. Moreover, this strategy improves the crystallinity and surface hydrophobicity of PVK and optimizes the energy level alignment of PSCs. As a result, all photovoltaic parameters are improved after optimization, where the power conversion efficiency (PCE) of PSCs has increased from 17.01% to 18.36%. Meanwhile, the optimized PSCs show excellent environmental stability, which can be stably stored in air (RH = 10-20%) for about 800 h.","CsPbI; defect passivation; interface engineering; perovskite solar cell; photovoltaic performance; stability","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-04-27","","","Photovoltaic Materials and Devices","","",""
"uuid:1e194659-cded-4b6a-8873-76e77cf987df","http://resolver.tudelft.nl/uuid:1e194659-cded-4b6a-8873-76e77cf987df","Assembly of Core/Shell Nanospheres of Amorphous Hemin/Acetone-Derived Carbonized Polymer with Graphene Nanosheets for Room-Temperature NO Sensing","Wang, Jianqiang (South China Normal University); Gao, Yixun (South China Normal University); Chen, Fengjia (Sun Yat-sen University); Zhang, Lulu (South China Normal University); Li, Hao (South China Normal University); De Rooij, Nicolaas Frans (South China Normal University); Umar, Ahmad (Najran University); Lee, Yi Kuen (The Hong Kong University of Science and Technology); French, P.J. (TU Delft Bio-Electronics)","","2022","Implementing parts per billion-level nitric oxide (NO) sensing at room temperature (RT) is still in extreme demand for monitoring inflammatory respiratory diseases. Herein, we have prepared a kind of core-shell structural Hemin-based nanospheres (Abbr.: Hemin-nanospheres, defined as HNSs) with the core of amorphous Hemin and the shell of acetone-derived carbonized polymer, whose core-shell structure was verified by XPS with argon-ion etching. Then, the HNS-assembled reduced graphene oxide composite (defined as HNS-rGO) was prepared for RT NO sensing. The acetone-derived carbonized polymer shell not only assists the formation of amorphous Hemin core by disrupting their crystallization to release more Fe-N4 active sites, but provides protection to the core. Owing to the unique core-shell structure, the obtained HNS-rGO based sensor exhibited superior RT gas sensing properties toward NO, including a relatively higher response (Ra/Rg = 5.8, 20 ppm), a lower practical limit of detection (100 ppb), relatively reliable repeatability (over 6 cycles), excellent selectivity, and much higher long-term stability (less than a 5% decrease over 120 days). The sensing mechanism has also been proposed based on charge transfer theory. The superior gas sensing properties of HNS-rGO are ascribed to the more Fe-N4 active sites available under the amorphous state of the Hemin core and to the physical protection by the shell of acetone-derived carbonized polymer. This work presents a facile strategy of constructing a high-performance carbon-based core-shell nanostructure for gas sensing.","carbonized polymer; core-shell structure; graphene; Hemin; nitric oxide sensor","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Bio-Electronics","","",""
"uuid:a64bd1c0-74d3-4c4e-b0eb-1aa43b626e85","http://resolver.tudelft.nl/uuid:a64bd1c0-74d3-4c4e-b0eb-1aa43b626e85","Red-Emitting SrGa2O4:Cu2+Phosphor with Super-Long Persistent Luminescence","Wang, Lei (Hefei University of Technology); Wang, Cailu (Hefei University of Technology); Chen, Y. (Hefei University of Technology); Jiang, Yang (Hefei University of Technology); Chen, Lei (Hefei University of Technology); Xu, Jinzhang (Hefei University of Technology); Qu, Bingyan (Hefei University of Technology); Hintzen, H.T.J.M. (TU Delft RST/Luminescence Materials)","","2022","The red afterglow of current rare-earth-activated long persistent luminescence (LPL) phosphors is largely still less than 6 h, in contrast to the 20 or 30 h long blue- or green-emitting ones, becoming the main obstacle to realize their multiscenario applications in practice. Herein, we report a rare-earth-free red-emitting LPL phosphor SrGa2O4:Cu2+that can exhibit an afterglow at about 622 nm lasting over 30 h, which can largely match with the luminance of current blue- or green-emitting LPL phosphors. We find that the Cu2+ion could be charged by ultraviolet light from 280 to 420 nm, and the emission has a very broad band with a full width at half-maximum of about 150 nm. Combining the thermoluminescence measurement and the first-principles calculation, we find that the O vacancies and the -1 charged Ga vacancies could store the holes and contribute to the LPL of SrGa2O4:Cu2+. Our results may dramatically promote and expand its potential applications and stimulate the research of the multicolor LPL phosphors in future.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","RST/Luminescence Materials","","",""
"uuid:a45a2e16-128d-4eff-9167-dc3b61ae6261","http://resolver.tudelft.nl/uuid:a45a2e16-128d-4eff-9167-dc3b61ae6261","Increasing the molecular weight of conjugated polyelectrolytes improves the electrochemical stability of their pseudocapacitor gels","Vázquez, Ricardo Javier (National University of Singapore; Nanyang Technological University); Quek, Glenn (National University of Singapore); McCuskey, Samantha R. (National University of Singapore; Nanyang Technological University); Llanes, Luana (University of California); Kundukad, Binu (Nanyang Technological University); Wang, Xuehang (TU Delft RST/Storage of Electrochemical Energy); Bazan, Guillermo C. (National University of Singapore; Nanyang Technological University)","","2022","Conjugated polyelectrolyte (CPE) hydrogels synergize the electrical properties of redox-active polymers with the physical properties of hydrogels. Of particular relevance is their implementation as pseudocapacitors due to their high ionic conductivity, strong ionic-electronic coupling, and large electroactive surface area. To date, efforts to improve the cycling stability of such hydrogels are predominated by the use of additives - optimization of the CPE's intrinsic properties remains underexplored. Herein, the systematic increase in the molecular weight (MW) of a self-doped CPE, namely CPE-K, has been demonstrated as an effective strategy to enhance the cycling stability of the resulting hydrogel. At high MW, mechanically stronger hydrogels were obtained with a specific capacitance as high as 88 ± 4 F g−1 at 0.25 A g−1 and a cycling stability of 76% capacitance retention after 100 000 cycles at 2.5 A g−1. Furthermore, this strategy yields a wider working pseudocapacitive window, less internal resistance, and higher ionic conductivity within the 3D conductive network. We attribute the enhanced electrochemical performance to stronger inter-chain contacts for optimal morphological organization, as revealed by rheological measurements, resulting in stress-tolerant hydrogels with a higher degree of percolation within a 3D conductive network. These results position CPE-K hydrogels as a state-of-the-art organic material for long-term pseudocapacitive technologies and potentially for the next generation of multi-functional pseudocapacitive devices that go beyond high energy density and power density.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","RST/Storage of Electrochemical Energy","","",""
"uuid:0f5a692d-7371-4266-b6aa-42a4298df32a","http://resolver.tudelft.nl/uuid:0f5a692d-7371-4266-b6aa-42a4298df32a","Spatial dynamic metabolomics identifies metabolic cell fate trajectories in human kidney differentiation","Wang, Gangqi (Leiden University Medical Center); Heijs, Bram (Leiden University Medical Center); Kostidis, Sarantos (Leiden University Medical Center); Rietjens, Rosalie G.J. (Leiden University Medical Center); Mahfouz, A.M.E.T.A. (TU Delft Pattern Recognition and Bioinformatics; Leiden University Medical Center); Chuva de Sousa Lopes, Susana M. (Leiden University Medical Center); van den Berg, Cathelijne W. (Leiden University Medical Center); van den Berg, Bernard M. (Leiden University Medical Center); Rabelink, Ton J. (Leiden University Medical Center)","","2022","Accumulating evidence demonstrates important roles for metabolism in cell fate determination. However, it is a challenge to assess metabolism at a spatial resolution that acknowledges both heterogeneity and cellular dynamics in its tissue microenvironment. Using a multi-omics platform to study cell-type-specific dynamics in metabolism in complex tissues, we describe the metabolic trajectories during nephrogenesis in the developing human kidney. Exploiting in situ analysis of isotopic labeling, a shift from glycolysis toward fatty acid β-oxidation was observed during the differentiation from the renal vesicle toward the S-shaped body and the proximal tubules. In addition, we show that hiPSC-derived kidney organoids are characterized by a metabolic immature phenotype that fails to use mitochondrial long-chain fatty acids for energy metabolism. Furthermore, supplementation of butyrate enhances tubular epithelial differentiation and maturation in cultured kidney organoids. Our findings highlight the relevance of understanding metabolic trajectories to efficiently guide stem cell differentiation.","cell metabolism; fetal kidney development; hiPSC-derived kidney organoids; MALDI-MSI; multi-omics metabolomics; nephrogenesis; proximal tubule development; single cell; spatial dynamic metabolomics","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:344797c6-a7ae-47a5-a4a8-b069f299cc75","http://resolver.tudelft.nl/uuid:344797c6-a7ae-47a5-a4a8-b069f299cc75","Lanthanide-Doped Nanoprobes as Orthogonal NIR-II Fluorescence Channels for In Vivo Information Storage","Wang, Xiaolu (Capital Normal University); Jia, Q. (TU Delft BT/Biocatalysis; Beijing Normal University); Ma, Liyi (Capital Normal University); Zhai, Xuejiao (Capital Normal University); Liu, Yuxin (Capital Normal University; Max-Planck-Inst. F. Kolloid-und G.); Liao, Xianquan (Capital Normal University); Zhou, Jing (Capital Normal University)","","2022","Information storage in vivo will lead to next-generation identification and security authentication. Here, an information storage method was proposed for in vivo application by using a pair of lanthanide-doped nanoprobes (NdNPs and ErNPs) with orthogonal emissions in the second near-infrared window. The information is stored in different fluorescence channels separately, while the selective readout could be realized by simply manipulating excitation wavelengths. The small-animal experiments primarily confirm the applicability of this method in vivo. The binary numbers ″1″ and ″0″ are implanted under the mice's skin, and the corresponding signals ″on″ and ″off″ can be collected by charge-coupled devices under different laser filter combinations. The design of lanthanide-doped probes with the nanoscale features and orthogonal emissions is expected to provide a new strategy for information storage in vivo. The lanthanide materials with excellent down-conversion near-infrared fluorescence performance have shown great application potential in the field of photonics.","information storage; multichannel imaging; orthogonal; rare earth-based nanoparticles; second near-infrared window","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","BT/Biocatalysis","","",""
"uuid:6a7e0774-322a-42f6-af25-73cd221106a0","http://resolver.tudelft.nl/uuid:6a7e0774-322a-42f6-af25-73cd221106a0","Response of hydrogeological processes in a regional groundwater system to environmental changes: A modeling study of Yinchuan Basin, China","Li, J. (Chang'an University); Zhou, Yangxiao (Hebei University of Geosciences; IHE Delft Institute for Water Education); Wang, Wenke (Chang'an University); Liu, S. (TU Delft Water Resources; IHE Delft Institute for Water Education); Li, Ying (Geological Bureau of Ningxia Hui Autonomous Region, Yinchuan); Wu, Ping (Institute of Hydrogeology and Environmental Geology of Ningxia, Yinchuan)","","2022","The sustainable development of groundwater resources in arid and semi-arid regions is a challenging task hindered by climate change and human activities. The rational utilization and management of groundwater resources is, therefore, dependent on an understanding of the influences of human and climatic factors on the spatial distribution of groundwater resources and their change over time. The thick Quaternary aquifers in the Yinchuan Basin, China were used herein as an example of how to quantitatively assess spatial and temporal trends in groundwater resources in response to human activities and climate change. A 3D transient groundwater flow model was constructed and used to simulate the evolution and spatial variability of hydrogeological processes from 1990 to 2020. By subsequently applying regime shift detection and correlation analysis to the simulation results, we found that: 1) groundwater storage was continuously depleted over the 30-year period, reaching a cumulative depletion of 1.89×109 m3; 2) human activities were mainly responsible for variations in regional hydrogeological processes for a period of up to 30 years. Climate only affected short-term interannual fluctuations in groundwater storage; 3) human activities (e.g., river water diversion and groundwater abstractions) were the decisive factors causing a continuous reduction of groundwater resources. A policy-driven reduction in water diversion from the Yellow River directly led to a significant drop in groundwater storage, which had a consequent effect on surface water and groundwater interactions and altered agricultural irrigation patterns (crop patterns and irrigation methods); 4) the amount of groundwater recharge from the Yellow River and local lakes increased from 1990 to 2020, whereas the discharge of groundwater to the Yellow River and lakes decreased.","Climate change; Human activities; Numerical groundwater flow model; Quaternary sediments, Yinchuan Basin; Surface water-groundwater interactions","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Water Resources","","",""
"uuid:c408e378-44e1-4a02-8c26-77e3885d6fad","http://resolver.tudelft.nl/uuid:c408e378-44e1-4a02-8c26-77e3885d6fad","Turning Maneuver Prediction of Connected Vehicles at Signalized Intersections: A Dictionary Learning-Based Approach","ZHANG, H. (TU Delft Civil Engineering & Geosciences; Chang'an Univieristy); Fu, Rui (Chang'an University); Wang, Chang (Chang'an Univieristy); Guo, Yingshi (Chang'an University); Yuan, W. (Chang'an University)","","2022","Vehicle-to-Infrastructure (V2I) communication has provided a solution for the improvement of the traffic efficiency of smart city intersections. For example, turning maneuvers prediction at signalized intersections in a connected environment helps traffic command centers time traffic lights and dynamically predict traffic flow. However, the modeling methods used in existing research on this topic have some limitations, such as poor scalability and interpretability of machine learning. Thus, this study proposes a dictionary learning-based approach to predict turning maneuvers before the intersection. The proposed dictionary model estimates the LogDet divergence-based sparse inverse covariance matrix (LDbSICM) of driving behavior samples. The graphical lasso method is used to estimate the sparse inverse covariance matrix of the driving samples to construct a dictionary library of the maneuver behavior. The LogDet divergence is used to calculate the difference between each inverse covariance matrix. A driving simulator is utilized to collect experimental data consisting of turning left (TL), turning right (TR), and going straight (GS) behaviors to establish and evaluate the proposed model. The experimental results demonstrate that the proposed dictionary learning-based turning maneuver prediction model achieves 100% prediction accuracy for TL and GS and 97.2% for TR. The proposed model has substantial advantages over existing methods. The model can predict TL, TR, and GS in a connected environment 270, 280, and 290 m, respectively, before the intersection.","Graphical lasso; LogDet divergence; signalized intersection; turning maneuver prediction; Vehicle-to-Infrastructure (V2I)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","Civil Engineering & Geosciences","","","","",""
"uuid:e343e224-9c2e-48e0-bed2-62d58dbf3d67","http://resolver.tudelft.nl/uuid:e343e224-9c2e-48e0-bed2-62d58dbf3d67","Active Fault-Tolerant Incremental Sliding-Mode Flight Control Against Control Reversal","Chang, J. (TU Delft Aerospace Structures & Computational Mechanics; Xidian University); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics)","","2022","","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-04-25","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:831ef593-b474-4678-9cb7-5cdafd91f111","http://resolver.tudelft.nl/uuid:831ef593-b474-4678-9cb7-5cdafd91f111","The Existence and Origin of Multiple Equilibria in Sand-Mud Sediment Beds","Colina Alonso, A. (TU Delft Coastal Engineering; Deltares); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Deltares; Shanghai Estuarine and Coastal Science Research Center); Herman, P.M.J. (TU Delft Environmental Fluid Mechanics; Deltares); van Weerdenburg, R.J.A. (Deltares); Huismans, Y. (TU Delft Coastal Engineering; Deltares); Holthuijsen, S. J. (NIOZ Royal Netherlands Institute for Sea Research; Waardenburg Ecology); Govers, L. L. (NIOZ Royal Netherlands Institute for Sea Research; University Medical Center Groningen); Bijleveld, A. I. (NIOZ Royal Netherlands Institute for Sea Research); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2022","The sediment composition of the seabed governs its mobility, hence determining sediment transport and morphological evolution of estuaries and tidal basins. Bed sediments often consist of mixtures of sand and mud, with spatial gradients in the sand/mud content. This study aims at increasing the understanding of processes driving the sediment composition in tidal basins, focusing on depositional processes. We show that bed sediments in the Wadden Sea tend to be either mud-dominated or sand-dominated, resulting in a bimodal distribution of the mud content where the two modes represent equilibrium conditions. The equilibria depend primarily on the sediment deposition fluxes, with bimodality originating from the dependence of suspended sand/mud concentrations on the local bed composition. Our analysis shows that bimodality is a phenomenon that is not only specific for the Wadden Sea; it can be expected for a wide range of suspended sediment concentrations and thus also in other systems worldwide.","bed composition; morphodynamics; sand-mud; sand-mud segregation; tidal basins; Wadden sea","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:2016a004-76a9-491f-b8b9-89396e79eaa3","http://resolver.tudelft.nl/uuid:2016a004-76a9-491f-b8b9-89396e79eaa3","Astronomical forcing of meter-scale organic-rich mudstone–limestone cyclicity in the Eocene Dongying sag, China: Implications for shale reservoir exploration","Zhang, Jianguo (China University of Geosciences); Jiang, Zaixing (China University of Geosciences); Liang, Chao (China University of Petroleum (East China); Sinopec); Baars, T.F. (TU Delft Applied Geology); Wang, Y. (TU Delft Applied Geology); Abels, H.A. (TU Delft Applied Geology)","","2022","The middle Eocene Dongying sag in the Bohai Bay Basin of China has an estimated shale oil resource of approximately 1.1 billion t (8.06 billion bbl); flows of shale oil have been produced in the succession from tens of wells, where the daily production of a single well generally varies between 10 and 100 t (73.3–733 bbl). Therein, the mudrock successions composed of meter-scale mudstone–limestone couplets are the most important shale oil-producing layers. The controls on the deposition of the meter-scale mudstone–limestone couplets, however, remain enigmatic, constraining the analysis of lithofacies and, therefore, sweet spot distributions. Here, we analyze three continuously cored organic-rich successions of mudstone–limestone couplets (371 m [1217 ft] in total) in the middle Eocene Dongying sag, accompanied by decimeter- to meter-scale sampling and testing of mineralogy, organic geochemistry, and paleontology of the rocks. Our integrated cyclostratigraphic analysis shows that the observed mudstone–limestone couplets occur at periods that coincide with Milankovitch periodicities; 21-k.y. precession cycles are the main driver of the meter-scale mudstone–limestone couplets, with additional imprints of 41-k.y. obliquity cycles. Specifically, precession minima are associated with high summer insolation and consequently high summer monsoonal precipitation, which increased river discharge and terrigenous input to the basin, resulting in the deposition of siliciclastic-rich mudstones. In the study, low summer insolation during precession maxima led to decreased summer monsoonal precipitation, lower river discharge and terrigenous input, and increased lake water salinity, resulting in the deposition of authigenic lime mudstones. The shale reservoir quality kept pace with the orbital climate changes; compared with lime mudstones deposited during precession maxima, mudstones deposited during precession minima had higher total organic carbon, porosity, and oil content, but lower brittleness.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Applied Geology","","",""
"uuid:d1d67ddc-687e-4481-a804-ebb01b466c16","http://resolver.tudelft.nl/uuid:d1d67ddc-687e-4481-a804-ebb01b466c16","Clarifying the Relationship between the Lithium Deposition Coverage and Microstructure in Lithium Metal Batteries","Wang, Q. (TU Delft RST/Storage of Electrochemical Energy); Zhao, C. (TU Delft RST/Storage of Electrochemical Energy); Wang, Shuwei (Tsinghua University); Wang, Jianlin (Chinese Academy of Sciences); Liu, M. (TU Delft RST/Storage of Electrochemical Energy); Ganapathy, S. (TU Delft RID/TS/Instrumenten groep); Bai, Xuedong (Chinese Academy of Sciences); Li, Baohua (Tsinghua University); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2022","Improving the reversibility of lithium metal batteries is one of the challenges in current battery research. This requires better fundamental understanding of the evolution of the lithium deposition morphology, which is very complex due to the various parameters involved in different systems. Here, we clarify the fundamental origins of lithium deposition coverage in achieving highly reversible and compact lithium deposits, providing a comprehensive picture in the relationship between the lithium microstructure and solid electrolyte interphase (SEI) for lithium metal batteries. Systematic variation of the salt concentration offers a framework that brings forward the different aspects that play a role in cycling reversibility. Higher nucleation densities are formed in lower concentration electrolytes, which have the advantage of higher lithium deposition coverage; however, it goes along with the formation of an organic-rich instable SEI which is unfavorable for the reversibility during (dis)charging. On the other hand, the growth of large deposits benefiting from the formation of an inorganic-rich stable SEI is observed in higher concentration electrolytes, but the initial small nucleation density prevents full coverage of the current collector, thus compromising the plated lithium metal density. Taking advantages of the paradox, a nanostructured substrate is rationally applied, which increases the nucleation density realizing a higher deposition coverage and thus more compact plating at intermediate concentration (∼1.0 M) electrolytes, leading to extended reversible cycling of batteries.","","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:fefa9e0c-5150-466d-a4a2-6b2f41d972a3","http://resolver.tudelft.nl/uuid:fefa9e0c-5150-466d-a4a2-6b2f41d972a3","Spatiotemporal Changes and Driving Factors of Ecosystem Health in the Qinling-Daba Mountains","Xiang, Ting (Wuhan University); Meng, Xiaoliang (Wuhan University); Wang, Xinshuang (Ministry of Natural Resources, Xi'an); Xiong, Jing (Hubei Environmental Monitoring Central Station, Wuhan); Xu, Z. (TU Delft Geoscience and Remote Sensing)","","2022","Rapid industrialization and urbanization have accelerated land-use changes in mountainous areas, with dramatic impacts on ecosystem health. In particular, the Qinling-Daba Mountains, as China’s central water tower, ecological green lung, and biological gene bank, have rich resource endowments and extremely high ecological value and are an important protective wall to China’s ecological security. Therefore, understanding the level of ecosystem health and its drivers in the research area contributes to the conservation and restoration of the mountain ecosystem. Based on remote sensing image data and land-use data from 2000 to 2020, we explored the spatial characteristics of ecosystem health, and supplemented with socio-economic data to explore its driving factors. The results show that (1) the ecosystem health in the study area has been continuously improved during the study period, and the regional differences in ecological organization are the most prominent; (2) the level of ecosystem health in the Qinling-Daba Mountains has been spatially improved from the peripheral areas to the central area, showing significant spatial autocorrelation and local spatial aggregation; (3) the ecosystem health is influenced by a combination of natural and anthropogenic factors, among which the negative effect of GRDP is mainly concentrated in the eastern region, the negative effect of the proportion of built-up land gradually spreads to the western region, and the positive effect of the proportion of forest land has a large scale. This study contributes to a better understanding of ecosystem health in mountainous counties in China and provides useful information for policymakers to formulate ecological and environmental management policies.","driving factors; ecosystem health; GWR; Qinling-Daba Mountains; spatiotemporal characteristics","en","journal article","","","","","","","","","","Geoscience and Remote Sensing","","","",""
"uuid:3fdf434c-b508-436a-befa-797a89e741b8","http://resolver.tudelft.nl/uuid:3fdf434c-b508-436a-befa-797a89e741b8","Joint Analysis and Reliability Test of Epoxy-Based Nano Silver Paste Under Different Pressure-Less Sintering Processes","Wang, Xinyue (Fudan University); Zeng, Zejun (Fudan University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Zhang, Jing (Heraeus Materials Technology Shanghai Ltd. Shanghai); Liu, Pan (Fudan University)","","2022","Recent years, the sintered silver paste was introduced and further developed for power electronics packaging due to low processing temperature and high working temperature. The pressure-less sintering technology reduces the stress damage caused by the pressure to the chip, improves reliability, and is widely applied in manufacturing. Currently, most existed studies are focused on alcohol-based sintered silver pastes while resins have been demonstrated to improve the bonding properties of solder joints. Hence, the performance and sintering mechanisms with epoxy-based silver paste need to be further explored. In this work, a methodology for multifactor investigation is settled on the epoxy-based silver paste to reveal the relationship between the strength and the different influence factors. We first analyzed the characteristics of commercialized epoxy-based silver paste samples, including silver content, silver particle size, organic composition, sample viscosity, and thermal conductivity. Samples were then prepared for shear tests and microstructure analysis under different pressure-less sintering temperatures, holding time, substrate surface, and chip size. Full factor analysis results were further discussed in detail for correlation. The influence factors were ranked from strong to weak as follows: sintering temperature, substrate surface, chip size, and holding time. Finally, a thermal cycling test was carried out for reliability analysis. Epoxy residues are one of the possible reasons, which result in shear strength decreasing exponentially.","epoxy-based nano silver paste; low-temperature joint technology; power electronic packaging; pressure-less sintering","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Components, Technology and Materials","","",""
"uuid:d604d2f4-2a01-40d6-9dde-2a6b4b77859f","http://resolver.tudelft.nl/uuid:d604d2f4-2a01-40d6-9dde-2a6b4b77859f","Discrete Element Analysis on Mechanical Properties of Ballast Bed by Tamping in Railway Turnout Areas","Chi, Yihao (Beijing Jiaotong University); Xiao, Hong (Beijing Jiaotong University); Zhang, Zhihai (Beijing Jiaotong University); Fang, Shuwei (Line Branch Company); Wang, Haoyu (TU Delft Mechanics and Physics of Structures)","","2022","Turnout is the key component of the railway tracks for trains to change direction, which is vital to operational safety and passenger comfort. Therefore, it is of great importance to perform a scientific and reasonable tamping operation for turnout areas. In this paper, based on the commercial software EDEM and RECURDYN, a coupled simulation model of the large machine tamping device-rail-sleeper-ballast bed in the turnout area is jointly established, and the correctness of the model is verified by the test results of the lateral resistance of the ballast bed. The influence of tamping operation on the macro-and micromechanical properties of ballast bed at the switching part of railway turnout areas is studied and recommendations for the optimization of tamping operation are proposed. The results show that in the squeezing stage, strong force chains are distributed concentrately under sleepers, where the distribution range is approximately elliptical with a depth of 150 mm. After tamping, only the 200-mm ballast under the sleepers is compacted, where the compactness is increased by 5.9%. On the contrary, the compactness of the ballast in the sleeper crib is reduced by 27.4%, which is the weakest part. To ensure favorable tamping quality, the tamping sequence at the switching part of railway turnout areas is suggested to be conducted in order of first through track and then diverging track.","ballast track; discrete element method (DEM); macro; micro mechanical properties; tamping operation; turnout","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Mechanics and Physics of Structures","","",""
"uuid:667d438c-de8e-411b-84b6-7d9102118bb6","http://resolver.tudelft.nl/uuid:667d438c-de8e-411b-84b6-7d9102118bb6","Electrical characteristics and photodetection mechanism of TiO2/AlGaN/GaN heterostructure-based ultraviolet detectors with a Schottky junction","Zhan, Teng (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Sun, J. (TU Delft Electronic Components, Technology and Materials; Tsinghua University); Feng, Tao (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Zhang, Yulong (Tsinghua University); Zhou, Binru (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Zhang, Banghong (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Wang, Junxi (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Sarro, Pasqualina M (TU Delft Electronic Components, Technology and Materials); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2022","Recent research focusing on wide-bandgap and two-dimensional materials with a Schottky junction has provided a new concept for ultraviolet photodetectors. However, the working mechanism of the Schottky junction-based detector varies depending on the photosensitive materials used and the device structure. We demonstrated a TiO2/AlGaN/GaN heterostructure-based photodetector with a Schottky junction, integrating an ultraviolet photosensitive TiO2 nanolayer, a two-dimensional electron gas (2DEG) field effect transistor, and a metal-semiconductor Schottky diode. The spectral response wavelength region of the detector is 200-365 nm and the peak responsivity is 37.396 A W−1 at −5 V bias under 240 nm UV illumination, respectively. Meanwhile, a peak photo-to-dark current ratio (PDCR) of 5.1 × 102 at −2 V bias voltage was observed under 274 nm UV irradiation. This Schottky-based 2DEG heterostructure detector can realize three dominant working principles: (i) the Schottky emission mechanism at a low reverse voltage (0-1 V) before the current is fully turned on, (ii) the Poole-Frenkel emission mechanism at a medium reverse voltage (−1 to −2 V) with peak PDCR, and (iii) the Fowler-Nordheim tunneling mechanism at a high reverse voltage (>−2 V) with a high responsivity. Continuous cycle response measurement results indicate that the detectors have good response repeatability and reliability. The characteristics of response wavelength, responsivity, and stability show that the detector can be used for several commercial applications, including sunscreen UV monitoring and LED sterilization light source detection.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public. Correction: https://doi.org/10.1039/D2TC04491A","","2023-06-19","","","Electronic Components, Technology and Materials","","",""
"uuid:12832e2e-47b6-4324-b86b-abd4df23b203","http://resolver.tudelft.nl/uuid:12832e2e-47b6-4324-b86b-abd4df23b203","Singlet and triplet Cooper pair splitting in hybrid superconducting nanowires","Wang, Guanzhong (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Dvir, T. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Mazur, G.P. (TU Delft BUS/Quantum Delft; TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Liu, C. (TU Delft Architecture and the Built Environment; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); van Loo, N. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); ten Haaf, S.L.D. (TU Delft QRD/Goswami Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Bordin, A. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Gazibegovic, Sasa (Eindhoven University of Technology); Badawy, G.H.A. (Eindhoven University of Technology); Bakkers, Erik P.A.M. (Eindhoven University of Technology); Wimmer, M.T. (TU Delft QN/Wimmer Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)","","2022","In most naturally occurring superconductors, electrons with opposite spins form Cooper pairs. This includes both conventional s-wave superconductors such as aluminium, as well as high-transition-temperature, d-wave superconductors. Materials with intrinsic p-wave superconductivity, hosting Cooper pairs made of equal-spin electrons, have not been conclusively identified, nor synthesized, despite promising progress1–3. Instead, engineered platforms where s-wave superconductors are brought into contact with magnetic materials have shown convincing signatures of equal-spin pairing4–6. Here we directly measure equal-spin pairing between spin-polarized quantum dots. This pairing is proximity-induced from an s-wave superconductor into a semiconducting nanowire with strong spin–orbit interaction. We demonstrate such pairing by showing that breaking a Cooper pair can result in two electrons with equal spin polarization. Our results demonstrate controllable detection of singlet and triplet pairing between the quantum dots. Achieving such triplet pairing in a sequence of quantum dots will be required for realizing an artificial Kitaev chain7–9.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","Architecture and the Built Environment","","QRD/Kouwenhoven Lab","","",""
"uuid:17dd0e10-330a-4904-b81b-2820c4805b14","http://resolver.tudelft.nl/uuid:17dd0e10-330a-4904-b81b-2820c4805b14","Tunable Superconducting Coupling of Quantum Dots via Andreev Bound States in Semiconductor-Superconductor Nanowires","Liu, C. (TU Delft QRD/Wimmer Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, Guanzhong (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Dvir, T. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wimmer, M.T. (TU Delft QN/Wimmer Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)","","2022","Semiconductor quantum dots have proven to be a useful platform for quantum simulation in the solid state. However, implementing a superconducting coupling between quantum dots mediated by a Cooper pair has so far suffered from limited tunability and strong suppression. This has limited applications such as Cooper pair splitting and quantum dot simulation of topological Kitaev chains. In this Letter, we propose how to mediate tunable effective couplings via Andreev bound states in a semiconductor-superconductor nanowire connecting two quantum dots. We show that in this way it is possible to individually control both the coupling mediated by Cooper pairs and by single electrons by changing the properties of the Andreev bound states with easily accessible experimental parameters. In addition, the problem of coupling suppression is greatly mitigated. We also propose how to experimentally extract the coupling strengths from resonant current in a three-terminal junction. Our proposal will enable future experiments that have not been possible so far.","","en","journal article","","","","","","","","","","","QRD/Wimmer Group","","",""
"uuid:95ec177c-6a5c-401d-8a0a-62df1014ef10","http://resolver.tudelft.nl/uuid:95ec177c-6a5c-401d-8a0a-62df1014ef10","Turbidity maxima in estuarine networks: Dependence on fluvial sediment input and local deepening/narrowing with an exploratory model","Wang, Jinyang (Universiteit Utrecht); Dijkstra, Y.M. (TU Delft Mathematical Physics); de Swart, Huib E. (Universiteit Utrecht)","","2022","An estuarine turbidity maximum (ETM) results from various subtidal sediment transport mechanisms related to, e.g., river, tides, and density gradients, which have been extensively analysed in single-channel estuaries. However, ETMs have also been found in estuaries composed of multiple interconnected tidal channels, where the water and suspended fine sediments are exchanged at the junctions with possible occurrence of sediment overspill. The overall aim of this study is to understand the processes that determine the ETM dynamics in such channel networks. Specifically, focusing on the ETMs formation due to sediment transport by river flow and density-driven flow, the dependence of ETM locations in an idealised three-channel network on fluvial sediment input and the local deepening and narrowing of a seaward channel is investigated. It is found that the ETM dynamics in channels of a network is coupled, and hence, changes in one channel affect the ETM pattern in all channels. Sensitivity results show that, keeping river discharge fixed, a larger fluvial sediment input leads to the upstream shift of ETMs and an increase in the overall sediment concentration. Both deepening or narrowing of a seaward channel may influence the ETMs in the entire network. Furthermore, the effect of either deepening or narrowing of a seaward channel on the ETM locations in the network depends on the system geometry and the dominant hydrodynamic conditions. Therefore, the response of the ETM location to local geometric changes is explained by analysing the dominant sediment transport mechanisms. In addition to the convergence of sediment transport mechanisms in single-estuarine channels, ETM dynamics in networks is found to be strongly affected by net exchange of sediment between the branches of a network. We find that considering the sensitivity of net sediment transport to geometric changes is needed to understand the changing ETM dynamics observed in a real estuarine network.","sediment overspill; sediment transport; sediment trapping; tidal network; turbidity maximum","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:a5b18dde-f63f-45f9-a140-bfb7edb633f2","http://resolver.tudelft.nl/uuid:a5b18dde-f63f-45f9-a140-bfb7edb633f2","Enhancing Classifier Conservativeness and Robustness by Polynomiality","Wang, Z. (TU Delft Pattern Recognition and Bioinformatics); Loog, M. (TU Delft Pattern Recognition and Bioinformatics; University of Copenhagen)","","2022","We illustrate the detrimental effect, such as overconfident decisions, that exponential behavior can have in methods like classical LDA and logistic regression. We then show how polynomiality can remedy the situation. This, among others, leads purposefully to random-level performance in the tails, away from the bulk of the training data. A directly related, simple, yet important technical novelty we subsequently present is softRmax: a reasoned alternative to the standard softmax function employed in contemporary (deep) neural networks. It is derived through linking the standard softmax to Gaussian class-conditional models, as employed in LDA, and replacing those by a polynomial alternative. We show that two aspects of softRmax, conservativeness and inherent gradient regularization, lead to robustness against adversarial attacks without gradient obfuscation.","Adversarial attack and defense; Others; Transfer/low-shot/long-tail learning","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Pattern Recognition and Bioinformatics","","",""
"uuid:5efb5310-00b4-49d6-8d96-03a376c04d73","http://resolver.tudelft.nl/uuid:5efb5310-00b4-49d6-8d96-03a376c04d73","Frequency division multiplexing readout of a transition edge sensor bolometer array with microstrip-type electrical bias lines","Wang, Q. (SRON Netherlands Institute for Space Research; Rijksuniversiteit Groningen); Khosropanah, P. (SRON Netherlands Institute for Space Research); Van Der Kuur, J. (SRON Netherlands Institute for Space Research); de Lange, G. (SRON Netherlands Institute for Space Research); Audley, M. D. (SRON Netherlands Institute for Space Research); Aminaei, A. (SRON Netherlands Institute for Space Research); Ilyas, S. (SRON Netherlands Institute for Space Research); van der Tak, F.M. (SRON Netherlands Institute for Space Research; Rijksuniversiteit Groningen); Gao, J.R. (TU Delft ImPhys/Adam group; SRON Netherlands Institute for Space Research)","","2022","We demonstrate multiplexed readout of 43 transition edge sensor (TES) bolometers operating at 90 mK using a frequency division multiplexing (FDM) readout chain with bias frequencies ranging from 1 to 3.5 MHz and a typical frequency spacing of 32 kHz. We improve the previously reported performance of our FDM system by two important steps. First, we replace the coplanar wires with microstrip wires, which minimize the cross talk from mutual inductance. From the measured electrical cross talk (ECT) map, the ECT of all pixels is carrier leakage dominated. Only five pixels show an ECT level higher than 1%. Second, we reduce the thermal response speed of the TES detectors by a factor of 20 by increasing the heat capacity of the TES, which allows us to bias all TES detectors below 50% in transition without oscillations. We compare the current-voltage curves and noise spectra of the TESs measured in single-pixel mode and multiplexing mode. We also compare the noise equivalent power (NEP) and the saturation power of the bolometers in both modes, where 38 pixels show less than 10% difference in NEP and 5% difference in saturation power when measured in the two different modes. The measured noise spectrum is in good agreement with the simulated noise based on measured parameters from an impedance measurement, confirming that our TES is dominated by phonon noise.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","ImPhys/Adam group","","",""
"uuid:35bef57d-22e9-4202-b8ca-d0ccca6d5edd","http://resolver.tudelft.nl/uuid:35bef57d-22e9-4202-b8ca-d0ccca6d5edd","The feasibility of csem monitoring in gas hydrate production of the range of porosity and saturation","Li, Y. (Beijing University of Technology; Student TU Delft); Lu, H. (Peking University; Beijing University of Technology); Wang, L. (Beihang University); Eltayieb, M.F.M.I. (TU Delft Applied Geophysics and Petrophysics); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics)","Flowers, Simon (editor)","2022","Natural gas hydrates production tests over the last two decades has sown that production is not without risks. Indirect effects in the sedimentary rocks of phase changes are changes in porosity, permeability, and saturation. From a field production test site, porosity changes in the range of 15% to 19% and saturation from 5% to 60% were reported. Monitoring is in principle possible using an electromagnetic survey with a downhole vertical electric source and a horizontal electric field receiver on the seafloor. Computed model responses over a wide frequency range and for many depth locations of an electric current source show that both changes can be detected. Best detectability occurs when the current source is below the reservoir layer in case of changes differences can be detected above, inside and below the reservoir layer at frequencyies below 10 Hz. At a source operating frequency of 0.1 Hz maximum response difference between the two values in saturation occur when the source is 20 m above the top of the reservoir layer unil 100 m below the bottom. Only below the top of the reservoir there is almost no difference in the electric field amplitude between the two saturation levels below 10 Hz.","","en","conference paper","EAGE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Applied Geophysics and Petrophysics","","",""
"uuid:7ce486f0-1c37-4fea-830e-72287af21b6e","http://resolver.tudelft.nl/uuid:7ce486f0-1c37-4fea-830e-72287af21b6e","Fabrication of a Nanosize Hematite Pigment via Waste Ferrous Sulfate Recycling Using Sulfur Reduction","Wang, Ye (Sichuan University); Ren, Genkuan (Yibin University); Jiang, Bing (Sichuan University); Yang, Lin (Sichuan University); Zhang, Zhiye (Sichuan University); Wang, Xinlong (Sichuan University); Zhong, Yanjun (Sichuan University); Chen, Z. (TU Delft (OLD) MSE-3); Yang, Xiushan (Sichuan University); Morita, Kazuki (University of Tokyo); Ma, Wenhui (Kunming University of Science and Technology)","","2022","Nanometer-sized hematite was prepared via a two-step process. In the first step, FeSO4·7H2O was oxidized to Fe2(SO4)3 by oxygen in an acidic solution. In the second step, the Fe2(SO4)3 was reduced to nanosize hematite with sulfur vapor at 550 °C. The hematite has good thermal stability up to 500 °C and good colloid stability in water-based paint. Its properties satisfy the requirements of the international standard ISO 1248-A-I-1-a for an iron oxide red pigment. Graphical abstract: [Figure not available: see fulltext.]","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","(OLD) MSE-3","","",""
"uuid:49663411-1fa3-4294-89ea-cd80664dc6cc","http://resolver.tudelft.nl/uuid:49663411-1fa3-4294-89ea-cd80664dc6cc","Ion-Boosting the Charge Density and Piezoelectric Response of Ferroelectrets to Significantly High Levels","Wang, Ningzhen (University of Connecticut); van Turnhout, J. (TU Delft Team Kevin Rossi); Daniels, Robert (University of Connecticut); Wu, Chao (University of Connecticut); Huo, Jindong (University of Connecticut); Gerhard, Reimund (University of Potsdam); Sotzing, Gregory (University of Connecticut); Cao, Yang (University of Connecticut)","","2022","In contrast to molecular-dipole polymers, such as PVDF, ferroelectrets are a new class of flexible spatially heterogeneous piezoelectric polymers with closed or open voids that act as deformable macro-dipoles after charging. With a spectrum of manufacturing processes being developed to engineer the heterogeneous structures, ferroelectrets are made with attractive piezoelectric properties well-suited for applications, such as pressure sensors, acoustic transducers, etc. However, the sources of the macro-dipole charges have usually been the same, microscopic dielectric barrier discharges within the voids, induced when the ferroelectrets are poled under a large electric field typically via a so-called corona poling, resulting in the separation and trapping of opposite charges into the interior walls of the voids. Such a process is inherently self-limiting, as the reverse internal field from the macro-dipoles eventually extinguishes the microdischarges, resulting in limited density of ions and not too high overall piezoelectric performance. Here, a new method to form ferroelectrets with gigantic electroactivity is proposed and demonstrated with the aid of an external ion booster. A laminate consisting of expanded polytetrafluoroethylene (ePTFE) and fluorinated-ethylene-propylene (FEP) was prefilled with bipolar ions produced externally by an ionizer and sequentially poled to force the separation of positive and negative ions into the open fibrous structure, rendering an impressive piezoelectric d33 coefficient of 1600 pC/N an improvement by a factor of 4 in comparison with the d33 of a similar sandwich poled with nonenhanced corona poling. The (pre)filling clearly increases the ion density in the open voids significantly. The charges stored in the open-cell structure stays at a high level for at least 4 months. In addition, an all-organic nanogenerator was made from an ePTFE-based ferroelectret, with conducting poly(3,4-ethylene dioxythiophene): poly(styrenesulfonate) (PEDOT: PSS) coated fabric electrodes. When poled with this ion-boosting process, it yielded an output power twice that of a similar sample poled in a conventional corona-only process. The doubling in output power is mainly brought about by the significantly higher charge density achieved with the aid of external booster. Furthermore, aside from the bipolar ions, extra monopolar ions can during the corona poling be blown into the open pores by using for instance a negative ionic hair dryer to produce a unipolar ePTFE-based ferroelectret with its d33 coefficient enhanced by a factor of 3. Ion-boosting poling thus unleashes a new route to produce bipolar or unipolar open-cell ferroelectrets with highly enhanced piezoelectric response.","bipolar and unipolar charging; corona charging; ePTFE ferroelectret; ion boost; piezoelectric response; wearable energy harvester","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-03-13","","","Team Kevin Rossi","","",""
"uuid:acabc0a1-e5a9-4a69-98af-36cfe0189687","http://resolver.tudelft.nl/uuid:acabc0a1-e5a9-4a69-98af-36cfe0189687","Urea-Functionalized Silver Catalyst toward Efficient and Robust CO2 Electrolysis with Relieved Reliance on Alkali Cations","Garg, Sahil (University of Queensland; Technical University of Denmark); Li, Mengran (TU Delft ChemE/Materials for Energy Conversion and Storage; University of Queensland); Hussain, Tanveer (University of Queensland; University of New England, Armidale); Idros, Mohamed Nazmi (University of Queensland); Wu, Yuming (University of Queensland); Zhao, Xiu Song (University of Queensland); Wang, Geoff G.X. (University of Queensland); Rufford, Thomas E. (University of Queensland)","","2022","We report a new strategy to improve the reactivity and durability of a membrane electrode assembly (MEA)-type electrolyzer for CO2 electrolysis to CO by modifying the silver catalyst layer with urea. Our experimental and theoretical results show that mixing urea with the silver catalyst can promote electrochemical CO2 reduction (CO2R), relieve limitations of alkali cation transport from the anolyte, and mitigate salt precipitation in the gas diffusion electrode in long-term stability tests. In a 10 mM KHCO3 anolyte, the urea-modified Ag catalyst achieved CO selectivity 1.3 times better with energy efficiency 2.8-fold better than an untreated Ag catalyst, and operated stably at 100 mA cm-2 with a faradaic efficiency for CO above 85% for 200 h. Our work provides an alternative approach to fabricating catalyst interfaces in MEAs by modifying the catalyst structure and the local reaction environment for critical electrochemical applications such as CO2 electrolysis and fuel cells.","CO2 utilization; electrocatalyst; membrane electrode assembly; silver nanoparticles; urea; vapor-fed electrolyzer","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:8c005fb1-e0cf-4fee-bb2d-666d43498d45","http://resolver.tudelft.nl/uuid:8c005fb1-e0cf-4fee-bb2d-666d43498d45","The multiplex relations between cities: a lexicon-based approach to detect urban systems","Tongjing, Wang (Universiteit Utrecht); Meijers, Evert (Universiteit Utrecht); Wang, H. (TU Delft Multimedia Computing)","","2022","Cities relate to other cities in many ways, and much scholarly effort goes into uncovering those relationships. Building on the principle that strongly related cities will co-occur frequently in texts, we propose a novel method to classify those toponym co-occurrences using a lexicon-based text-mining method. Millions of webpages are analysed to retrieve how 293 Chinese cities are related in terms of six types: industry, information technology, finance, research, culture and government. Each class displays different network patterns, and this multiplexity is mapped and analysed. Further refinement of this lexicon-based approach can revolutionize the study of inter-urban relationships.","city networks; multiplexity; text-mining; toponym co-occurrence; urban systems","en","journal article","","","","","","","","","","","Multimedia Computing","","",""
"uuid:09531596-69fb-49ef-9fe7-14a7d08e6778","http://resolver.tudelft.nl/uuid:09531596-69fb-49ef-9fe7-14a7d08e6778","Organizing for permanent beta: performance measurement before vs performance monitoring after release of digital services","van Oorschot, Kim E. (BI Norwegian Business School); Akkermans, Henk A. (Tilburg University); Van Wassenhove, Luk N. (INSEAD, Europe); Wang, Y. (TU Delft Research Data and Software)","","2022","Purpose: Due to the complexity of digital services, companies are increasingly forced to offer their services “in permanent beta”, requiring continuous fine-tuning and updating. Complexity makes it extremely difficult to predict when and where the next service disruption will occur. The authors examine what this means for performance measurement in digital service supply chains. Design/methodology/approach: The authors use a mixed-method research design that combines a longitudinal case study of a European digital TV service provider and a system dynamics simulation analysis of that service provider's digital service supply chain. Findings: With increased levels of complexity, traditional performance measurement methods, focused on detection of software bugs before release, become fragile or futile. The authors find that monitoring the performance of the service after release, with fast mitigation when service incidents are discovered, appears to be superior. This involves organizational change when traditional methods, like quality assurance, become less important. Research limitations/implications: The performance of digital services needs to be monitored by combining automated data collection about the status of the service with data interpretation using human expertise. Investing in human expertise is equally important as investing in automated processes. Originality/value: The authors draw on unique empirical data collected from a digital service provider's struggle with performance measurement of its service over a period of nine years. The authors use simulations to show the impact of complexity on staff allocation.","Digital services; Performance measurement; Resource allocation; System dynamics","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-07-01","","","Research Data and Software","","",""
"uuid:56217175-b7d1-4379-a5e3-d7d97879ccc4","http://resolver.tudelft.nl/uuid:56217175-b7d1-4379-a5e3-d7d97879ccc4","Editorial: Antibiotics in Water: Impacts and Control Technologies","Zhang, Yongjun (Nanjing Tech University); Hu, Jiangyong (National University of Singapore); Nomngongo, Philiswa Nosizo (University of Johannesburg); Wang, Qilin (University of Technology Sydney); Spanjers, H. (TU Delft Sanitary Engineering)","","2022","","advanced oxidation; emerging organic contaminant; ozonation; pharmaceutical; transformation product","en","contribution to periodical","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:a3612e3a-3b53-41c6-88cb-b6bd68e818f0","http://resolver.tudelft.nl/uuid:a3612e3a-3b53-41c6-88cb-b6bd68e818f0","Effect of Bio-oil on Rheology and Chemistry of Organosolv Lignin–Modified Bitumen","Zhang, Y. (TU Delft Pavement Engineering; Chang'an University); Liu, X. (TU Delft Pavement Engineering); Ren, S. (TU Delft Pavement Engineering); Jing, R. (TU Delft Pavement Engineering); Lin, P. (TU Delft Pavement Engineering); Apostolidis, P. (TU Delft Pavement Engineering); Erkens, S. (TU Delft Pavement Engineering); Wang, Xuancang (Chang'an University); Scarpas, Athanasios (TU Delft Pavement Engineering; Khalifa University of Science and Technology)","","2022","Lignin, one of the most abundant natural polymers, has been extensively studied as an additive in bituminous binders. Even though the lignin improves the overall resistance against oxidative aging of bitumen, it could lead to high thermal cracking sensitivity. In this study, a bio-oil (i.e., rapeseed oil) is implemented in lignin-modified bitumen to ameliorate characteristics, such as the resistance to fatigue and cracking. The long-term aging of bitumens formulated by different proportions of bio-oil was simulated by the pressure aging vessel (PAV) method. Fourier Transform Infrared Spectroscopic (FTIR) results demonstrated lignin has a remarkable antiaging effect, but adding bio-oil will slightly deteriorate the antiaging effect. The Brookfield rotational viscometer showed that the addition of bio-oil was able to reduce the binder’s viscosity observably, thereby improving the workability of bitumen. The frequency sweep tests revealed that lignin increased the stiffness and improved the thermal stability. Also, the multiple stress creep recovery tests corroborated that lignin significantly enhanced the rutting resistance of binders. The fatigue and thermal cracking properties of lignin-modified binder could be strengthened by increasing bio-oil content which is confirmed from both linear amplitude sweep, Glover-Rowe parameter, and Bending Beam Rheometer (BBR) tests. Moreover, the relaxation test results demonstrated that bio-oil decreased the residual stress ratio and relaxation time dramatically. Overall, this study has shown preliminary conclusions on the incorporating of bio-oil to enhance the medium-low temperature properties of lignin-modified binders. In the meantime, bio-oil did not interfere with the improvement influence of lignin on the neat bitumen regarding high-temperature performance.","Bio-oil; Chemistry; Fatigue; Lignin-modified bitumen; Rheology; Thermal cracking","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Pavement Engineering","","",""
"uuid:246cc975-0d10-41c0-8274-8d6a7ded9edc","http://resolver.tudelft.nl/uuid:246cc975-0d10-41c0-8274-8d6a7ded9edc","ITIL: Interlaced Topologically Interlocking Lattice for continuous dual-material extrusion","Kuipers, T. (TU Delft Materials and Manufacturing; Ultimaker); Su, Renbo (The University of Manchester); Wu, J. (TU Delft Materials and Manufacturing); Wang, Charlie C.L. (The University of Manchester)","","2022","Material Extrusion (MEX) systems with dual-material capability can unlock interesting applications where flexible and rigid materials are combined. When chemically incompatible materials are concerned the adhesion between the two might be insufficient. Therefore researchers typically rely on dovetail type interlocking geometries in order to affix two bodies mechanically. However, dovetail type interlocking introduces extrusion discontinuities and relies on the material’s resistance to deformation, which is difficult to model. We propose a simple and effective 3D lattice consisting of interlaced horizontal beams in vertically alternating directions which interlock topologically: the interlaced topologically interlocking lattice (ITIL). It ensures continuous extrusion and ensures an interlock even for highly flexible materials. We develop analytical models for optimizing the ultimate tensile strength of the ITIL lattice in two different orientations relative to the interface: straight and diagonal. The analytical models are applied to polypropylene (PP) and polylactic acid (PLA) and verified by finite elements method (FEM) simulations and physical tensile experiments. In the diagonal orientation ITIL can obtain 82% of the theoretical upper bound of 8.6 MPa. ITIL seems to perform comparably to dovetail interlocking designs, while it lends itself to application to non-vertical interfaces. Optimizing the lattice for non-vertical interfaces, however, remains future work.","Continuous extrusion; Interlocking; Lattice structure; Material extrusion; Multi-material","en","journal article","","","","","","","","","","","Materials and Manufacturing","","",""
"uuid:310d0689-6bbc-4af9-8c4e-997d6ac95cbe","http://resolver.tudelft.nl/uuid:310d0689-6bbc-4af9-8c4e-997d6ac95cbe","RILEM TC 279 WMR round robin study on waste polyethylene modified bituminous binders: advantages and challenges","Tušar, Marjan (Slovenian National Building and Civil Engineering Institute; National Institute of Chemistry, Ljubljana); Kakar, Muhammad Rafiq (Swiss Federal Laboratories for Materials Science and Technology (Empa); Bern University of Applied Sciences); Poulikakos, Lily D. (Swiss Federal Laboratories for Materials Science and Technology (Empa)); Pasquini, Emiliano (Università degli Studi di Padova); Baliello, Andrea (Università degli Studi di Padova); Pasetto, Marco (Università degli Studi di Padova); Porot, Laurent (Kraton Chemical B.V.); Wang, Di (Technical University of Braunschweig); Lo Presti, Davide (Università degli Studi di Palermo); Varveri, Aikaterini (TU Delft Pavement Engineering)","","2022","Inter-laboratory experiments were designed to evaluate the impact of plastic waste blended directly in bitumen and to assess the properties, using conventional and advanced bituminous binder testing. The blends targeted 5% of plastic waste in 95% bitumen, using two types of polyethylene (PE) primary (pellets) and secondary (shreds) waste. The experiments showed that the addition of PE waste to bitumen does not alter the chemistry of the bitumen, the blending is physical. The DSR results indicate a strong dependency on the testing temperature as at low temperatures the composite material bitumen and PE behave both elastically whereas, at higher temperatures, the bitumen becomes viscoelastic. The MSCR tests indicated that the neat binder is more sensitive to permanent deformation compared to the blends with PE. The fatigue performance using the Linear Amplitude Sweep test showed a better performance in terms of stress and fatigue life for the PE blends.","Asphalt; performance; plastics; polyethylene; waste","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-07-05","","","Pavement Engineering","","",""
"uuid:66a6b145-9370-49ec-864f-95c1ff470563","http://resolver.tudelft.nl/uuid:66a6b145-9370-49ec-864f-95c1ff470563","OC6 Phase Ia: CFD Simulations of the Free-Decay Motion of the DeepCwind Semisubmersible","Wang, Lu (National Renewable Energy Laboratory); Robertson, Amy (National Renewable Energy Laboratory); Jonkman, Jason (National Renewable Energy Laboratory); Kim, Jang (Front Energies); Shen, Zhi‐Rong (Front Energies); Koop, Arjen (Maritime Research Institute Netherlands (MARIN)); Chandramouli, P. (TU Delft Wind Energy); Viré, A.C. (TU Delft Wind Energy); Ramesh Reddy, L. (TU Delft Wind Energy)","","2022","Currently, the design of floating offshore wind systems is primarily based on mid-fidelity models with empirical drag forces. The tuning of the model coefficients requires data from either experiments or high-fidelity simulations. As part of the OC6 (Offshore Code Comparison Collaboration, Continued, with Correlation, and unCertainty (OC6) is a project under the International Energy Agency Wind Task 30 framework) project, the present investigation explores the latter option. A verification and validation study of computational fluid dynamics (CFD) models of the DeepCwind semisubmersible undergoing free-decay motion is performed. Several institutions provided CFD results for validation against the OC6 experimental campaign. The objective is to evaluate whether the CFD setups of the participants can provide valid estimates of the hydrodynamic damping coefficients needed by mid-fidelity models. The linear and quadratic damping coefficients and the equivalent damping ratio are chosen as metrics for validation. Large numerical uncertainties are estimated for the linear and quadratic damping coefficients; however, the equivalent damping ratios are more consistently predicted with lower uncertainty. Some difference is observed between the experimental and CFD surge-decay motion, which is caused by mechanical damping not considered in the simulations that likely originated from the mooring setup, including a Coulomb-friction-type force. Overall, the simulations and the experiment show reasonable agreement, thus demonstrating the feasibility of using CFD simulations to tune mid-fidelity models.","CFD; validation; free decay; offshore wind; semisubmersible; uncertainty; OC6; IEA; Free decay; Validation; Uncertainty; Semisubmersible; Offshore wind","en","journal article","","","","","","","","","","","Wind Energy","","",""
"uuid:cd4c4470-42b4-4921-a8a3-392469598687","http://resolver.tudelft.nl/uuid:cd4c4470-42b4-4921-a8a3-392469598687","An aeroelastic optimisation framework for manufacturable variable stiffness composite wings including critical gust loads","Wang, Z. (TU Delft Aerospace Structures & Computational Mechanics); Peeters, D.M.J. (TU Delft Aerospace Structures & Computational Mechanics); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics)","","2022","This work presents a new aeroelastic optimisation framework for the preliminary design of variable stiffness composite wing structures. The framework is constructed by sequentially and iteratively solving two sub-problems: aeroelastic tailoring and lay-up retrieval, using gradient-based algorithms with full-analytical sensitivities provided. During aeroelastic tailoring, the wing mass is minimised by optimising the lamination parameters and thickness of wing laminates together with wing jig twist distribution. The load cases cover not only static loads, but also the critical gust loads that are identified across the entire flight envelop at every iteration of optimisation. Further, a cruise shape constraint is included in addition to other aerostructural constraints, so that the optimal aircraft performance can be ensured. During lay-up retrieval, the manufacturable stacking sequence is retrieved according to the optimal lamination parameters with the consideration of minimal steering radius constraint. Moreover, to fix the possible constraint violations caused by lay-up retrieval, a correction strategy is incorporated to tighten the violated constraints for repeating aeroelastic tailoring. Finally, several case studies on the design of NASA common research model wing are carried out and investigated. The results indicate that the critical gust loads and cruise shape constraint have a large influence on the design of tow-steered composite wing structures, which therefore demonstrate the usefulness and benefits of the proposed optimisation framework.","Aeroelastic optimisation; Critical gust loads; Cruise shape constraint; Manufacturability constraint; Variable stiffness composites","en","journal article","","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:e79944b9-b49f-4ec3-9532-52732b0895b0","http://resolver.tudelft.nl/uuid:e79944b9-b49f-4ec3-9532-52732b0895b0","Collaborative Design of a Business Jet Family Using the AGILE 4.0 MBSE Environment","Bussemaker, J.H. (Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Ciampa, P.D. (Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Singh, J. (Bombardier Aviation); Fioriti, M. (Politecnico di Torino); Cabaleiro, C. (Politecnico di Torino); Wang, Z. (TU Delft Aerospace Structures & Computational Mechanics); Peeters, D.M.J. (TU Delft Aerospace Structures & Computational Mechanics); Della Vecchia, Pierluigi (Università degli Studi di Napoli Federico II); Hansmann, P. (Rheinisch-Westfälische Technische Hochschule)","","2022","This paper presents the collaborative model-based design of a business jet family. In family design, a trade-off is made between aircraft performance, reducing fuel burn, and commonality, reducing manufacturing costs. The family is designed using Model-Based Systems Engineering (MBSE) methods developed in the AGILE 4.0 project. The EC-funded AGILE 4.0 project extends the scope of the preliminary aircraft design process to also include systems engineering phases and new design domains like manufacturing, maintenance, and certification. Stakeholders, needs, requirements, and architecture models of the business jet family are presented. Then, the collaborative Multidisciplinary Design Analysis and Optimization (MDAO) capabilities are used to integrate various aircraft design disciplines, including overall aircraft design, onboard systems design, wing structural sizing, tailplane sizing, mission analysis, and cost estimation. Decisions regarding the degree of commonality are implemented by optionally fixing the design of a shared component when sizing an aircraft.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:ff04501f-26f0-4d16-9dc4-7221b07da36d","http://resolver.tudelft.nl/uuid:ff04501f-26f0-4d16-9dc4-7221b07da36d","Multidisciplinary Design and Optimization of Regional Jet Retrofitting Activity","Mandorino1, M. (Università degli Studi di Napoli Federico II); Della Vecchia, Pierluigi (Università degli Studi di Napoli Federico II); Corcione, S. (Università degli Studi di Napoli Federico II); Nicolosi, F. (Università degli Studi di Napoli Federico II); Trifari, V. (Università degli Studi di Napoli Federico II); Cerino, G. (Leonardo Aircraft Division); Fioriti, M. (Politecnico di Torino); Wang, Z. (TU Delft Aerospace Structures & Computational Mechanics); Peeters, D.M.J. (TU Delft Aerospace Structures & Computational Mechanics)","","2022","A retrofit analysis on a 90 passengers regional jet aircraft is performed through a multidisciplinary collaborative aircraft design and optimization highlighting the impact on costs and performance. Two different activities are accounted for selecting the best aircraft retrofit solution: a re-engining operation that allows to substitute a conventional power-plant platform with advanced geared turbofan and an on-board-systems architecture modernization, considering different levels of electrification. Besides the variables that are directly dependent from these activities, also scenario variables are considered during the optimization such as the fuel price, the fleet size and the years of utilization of the upgraded systems. The optimization is led by impacts of the retrofitting process on emissions, capital costs and saving costs, computed at industrial level. Overall aircraft design competences (aerodynamics, masses, performance, noise, and emissions) have been computed increasing the level of fidelity and reliability. The whole process is implemented in the framework of the AGILE 4.0 research project in a collaborative remote multidisciplinary approach. Results show that the engine retrofitting can be a profitable solution for both manufacturers and airliners. Conversely, the on-board-system electrification seems to be not convenient in a retrofitting process due to the high capital costs. Depending on the operative scenario, involved stakeholders can properly orient their decision on a retrofitting strategy.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:cf5d47e5-44fd-4c6e-a72a-bb84d489a904","http://resolver.tudelft.nl/uuid:cf5d47e5-44fd-4c6e-a72a-bb84d489a904","From natural environment to artificial system: Chang'an and its water system in the Western Han Dynasty","Wang, R. (TU Delft History, Form & Aesthetics; Tongji University); Hein, C.M. (TU Delft History, Form & Aesthetics)","","2022","People around the world have shaped societies and urban spaces around water for millennia. They have transformed natural water structures and patterns to serve their diverse needs. The ways in which historical decisions affect contemporary water systems and influence future planning of urban systems still need to be fully recognized. This paper explores the multiple roles of water systems in Chang'an during the Western Han Dynasty. Chang'an, one of the ancient names for the city of Xi'an, was a typical capital city of China and East Asia in early ancient times. This study explores everyday practices pertaining to water as well as its role in defense, gardening, politics and culture. Drawing upon three historical theories, this study presents findings that water was embedded in the design of traditional Chinese capitals. The siting and construction of capital cities was first based on the Theory of Choosing the Center (3rd century BCE) and the Theory of Conforming to Nature (5th–3rd century BCE). However, the final maturation of this urban morphology, including the water system, was closely related to the Theory of Symbolizing and Modeling Heaven and Earth (4th–3rd century BCE), in a way that manifested the imperial power's organization and control of space and time. Through close analysis of historical documents, archaeological reports and modern investigations, the paper aims to clarify, analyze and summarize the historical context and evolution, functional and structural characteristics, as well as the economic, political, cultural and military connotations of water systems in Chang'an. It argues that the coordination of urban construction and the water environment was a key foundation for capital city development. It proposes that people shaped urban water supply in many ways, including daily life, waterway transportation, agricultural irrigation, aquaculture promotion, military defense and fire prevention. The water system in Chang'an also provided an important place for royalty and nobility to go fishing, to hunt and to engage in leisure and naval training. The landscape with this water system as the core, including Taiye Lake and Kunming Lake, had also inspired Chinese gardening history, and had a profound impact on future generations. More importantly, the capital's urban morphology design was a miniature of the world recognized by the monarch, as well as the symbolic image of the supreme rulers' political and cultural desire to control and possess Tianxia, which essentially means the whole world. In conclusion, the paper calls for a closer study of water-based design as a foundation for urban planning.","Capital city; Chang'an; Kunming Lake; Symbolic image; Taiye Lake; Water system; Wei River; Xianyang","en","journal article","","","","","","","","","","","History, Form & Aesthetics","","",""
"uuid:3f9a5b71-0a5f-48b4-8eb7-183df27abd41","http://resolver.tudelft.nl/uuid:3f9a5b71-0a5f-48b4-8eb7-183df27abd41","Planning and developing a high-speed railway new town under state entrepreneurialism in China","Wang, B. (TU Delft Urban Development Management; Tsinghua University); de Jong, Martin (Erasmus Universiteit Rotterdam; Fudan University); van Bueren, Ellen (TU Delft Management in the Built Environment); Ersoy, A. (TU Delft Urban Development Management); Song, Yun (Erasmus Universiteit Rotterdam)","","2022","The development of high-speed railway (HSR) new towns in China represents a new phase of suburbanization and has had a significant impact on urban expansion, but not all of its mechanisms and drivers have been studied. This article aims to understand the booming development of HSR new towns in China through the theoretical lens of state entrepreneurialism. It dissects the entrepreneurial behaviors of the local state in a medium-sized city, which harnesses the HSR project strategically to develop a new town. Our findings reveal that local governments play out state entrepreneurialism in developing HSR new towns. They compete with other cities for HSR projects. They are motivated by land revenue generation, career advancement for officials, and maintaining state power. Furthermore, this article contributes to the understanding of interactions among multi-level governments. Local states in China can also exert influence on the policymaking and resource allocation of the national government.","China; HSR station areas; new towns; state entrepreneurialism","en","journal article","","","","","","","","","","Management in the Built Environment","Urban Development Management","","",""
"uuid:f91f5d79-c2aa-4b93-8274-423b9ea5b16a","http://resolver.tudelft.nl/uuid:f91f5d79-c2aa-4b93-8274-423b9ea5b16a","Lateral variation in slab window viscosity inferred from global navigation satellite system (GNSS)–observed uplift due to recent mass loss at Patagonia ice fields","Russo, Raymond M. (University of Florida); Luo, Haipeng (University of Victoria); Wang, Kelin (University of Victoria; Pacific Geoscience Centre); Ambrosius, B.A.C. (TU Delft Astrodynamics & Space Missions); Mocanu, Victor (Bucharest University); He, Jiangheng (Pacific Geoscience Centre); James, Thomas (University of Victoria; Pacific Geoscience Centre); Bevis, Michael (Ohio State University); Fernandes, Rui (University of Beira Interior)","","2022","The geographic coincidence of the Chile Ridge slab window and the Patagonia ice fields offers a unique opportunity for assessing the effects of slab window rheology on glacial isostatic adjustment (GIA). Mass loss of these ice fields since the Little Ice Age causes rapid but variable crustal uplift, 12–24 mm/yr around the North Patagonia ice field, increasing to a maximum of 41 mm/yr around the South Patagonia ice field, as determined from newly collected or processed geodetic data. We used these observational constraints in a three-dimensional Maxwell viscoelastic finite element model of GIA response above both the subducting slab and slab window in which the upper-mantle viscosity was parameterized to be uniform with depth. We found that the viscosity of the northern part of the slab window, ~2 × 1018 Pa·s, is lower than that of the southern part by approximately an order of magnitude. We propose that this along-strike viscosity contrast is due to late Cenozoic ridge subduction beneath the northern part of the slab window, which increases asthenospheric temperature and reduces viscosity","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Astrodynamics & Space Missions","","",""
"uuid:bce7b85c-1eb4-42bf-a603-f2a6b63370e2","http://resolver.tudelft.nl/uuid:bce7b85c-1eb4-42bf-a603-f2a6b63370e2","Generating Contextual Load Profiles Using a Conditional Variational Autoencoder","Wang, C. (TU Delft Intelligent Electrical Power Grids); Tindemans, Simon H. (TU Delft Intelligent Electrical Power Grids); Palensky, P. (TU Delft Intelligent Electrical Power Grids)","","2022","Generating power system states that have similar distribution and dependency to the historical ones is essential for the tasks of system planning and security assessment, especially when the historical data is insufficient. In this paper, we described a generative model for load profiles of industrial and commercial customers, based on the conditional variational autoencoder (CVAE) neural network architecture, which is challenging due to the highly variable nature of such profiles. Generated contextual load profiles were conditioned on the month of the year and typical power exchange with the grid. Moreover, the quality of generations was both visually and statistically evaluated. The experimental results demonstrate our proposed CVAE model can capture temporal features of historical load profiles and generate ‘realistic’ data with satisfying univariate distributions and multivariate dependencies.","CVAE; generative model; load profiles; synthetic data","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-05-29","","","Intelligent Electrical Power Grids","","",""
"uuid:8b02db61-932b-44e2-a200-6d3351d653dc","http://resolver.tudelft.nl/uuid:8b02db61-932b-44e2-a200-6d3351d653dc","Generating multivariate load states using a conditional variational autoencoder","Wang, C. (TU Delft Intelligent Electrical Power Grids); Sharifnia, E. (TU Delft Intelligent Electrical Power Grids); Gao, Zhi (Student TU Delft); Tindemans, Simon H. (TU Delft Intelligent Electrical Power Grids); Palensky, P. (TU Delft Intelligent Electrical Power Grids)","","2022","For planning of power systems and for the calibration of operational tools, it is essential to analyse system performance in a large range of representative scenarios. When the available historical data is limited, generative models are a promising solution, but modelling high-dimensional dependencies is challenging. In this paper, a multivariate load state generating model on the basis of a conditional variational autoencoder (CVAE) neural network is proposed. Going beyond common CVAE implementations, the model includes stochastic variation of output samples under given latent vectors and co-optimizes the parameters for this output variability. It is shown that this improves statistical properties of the generated data. The quality of generated multivariate loads is evaluated using univariate and multivariate performance metrics. A generation adequacy case study on the European network is used to illustrate model's ability to generate realistic tail distributions. The experiments demonstrate that the proposed generator outperforms other data generating mechanisms.","CVAE; Generative model; Load modelling; Multivariate dependence; System adequacy","en","journal article","","","","","","","","","","","Intelligent Electrical Power Grids","","",""
"uuid:3992c564-6b6c-478e-b566-5c6d5362c9e2","http://resolver.tudelft.nl/uuid:3992c564-6b6c-478e-b566-5c6d5362c9e2","Plasmon resonance spectral peak shift due to morphing of gold nanoparticles for strain sensing","Wang, X. (TU Delft Structural Integrity & Composites); Benedictus, R. (TU Delft Structural Integrity & Composites); Groves, R.M. (TU Delft Structural Integrity & Composites)","Berghmans, Francis (editor); Zergioti, Ioanna (editor)","2022","The plasmon resonance spectral peak of a gold spherical nanoparticle (NP) will shift when the NP shape is changed from sphere to spheroid. This may be used as a novel strain detection method with gold NPs embedded in a medium of different refractive index (RI). Applying a strain to the external medium will cause a change in the shape of the NP from spherical to spheroidal. In our previous work, it was found that when the RI change of the medium surrounding the NPs is close to zero, the shape change induced plasmon resonance spectral peak shift will become important. In order to obtain only the wavelength shift values caused by the shape change of the NPs, the RI of medium surrounding the gold NPs is set at a constant of 1.45 and the RI of the gold NP is assumed unchanged. The T-matrix method is used to calculate the scattered light and light extinction by the NP morphing. The diameters of the gold NPs are set from 100 nm to 400 nm, with the size interval at 10 nm, to cover a wide size range for typical sizes of gold spherical NPs. The spectra of the light scattering and light extinction were calculated on the Delft University high performance computing cluster. The results show that the plasmon resonance spectral peak shift is related to the size of the NPs. Larger sizes of gold NPs have larger peak shift values, but there is an inflection point around 200 nm and the bandwidth of the resonance peak becomes larger which will cause a difficulty in precisely locating the peak.","gold nanoparticle; plasmon resonance; spectral shift; Strain sensing","en","conference paper","SPIE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-11-28","","","Structural Integrity & Composites","","",""
"uuid:53e6cc0b-7ddf-4f89-a8b2-1104c38ec3db","http://resolver.tudelft.nl/uuid:53e6cc0b-7ddf-4f89-a8b2-1104c38ec3db","Preliminary aeroelastic design of composite wings with distributed electric propulsion","Wang, Z. (TU Delft Aerospace Structures & Computational Mechanics); Liu Xu, Vanessa Q. (Student TU Delft); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics)","Fajardo, Pablo (editor)","2022","In the development of electric aircraft, the use of distributed electric propulsion introduces a potential occurrence of propeller whirl flutter, which needs to be taken into account for wing structural design. To this end, this work extends an in-house aeroelastic optimization tool by means of including a post-processing procedure on whirl flutter analysis. In aeroelastic optimization, propellers are modeled as concentrated masses, and the wing mass is minimized by tailoring the lamination parameters and thickness of wing laminates subject to aerostructural design constraints. For the whirl flutter analysis of the optimized wing, a new aeroelastic model is built by coupling propeller motions and aerodynamic loads into wing aeroelastic model. The usefulness of the purposed approach is demonstrated using a numerical example, where the required inputs on propeller mounting properties are determined via a parametric study. The result indicates that flexibly mounting propellers on a flexible wing leads to the decrease of wing flutter speed, and it also confirms that the propeller mounting properties have a large influence on aeroelastic instability of the coupled propeller-wing system.","Aeroelastic optimization; composite wings; DEP; electric aircraft; whirl flutter","en","conference paper","International Forum on Aeroelasticity and Structural Dynamics (IFASD)","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:05387c30-37ea-4fe6-b82a-b6ee3d7b73ec","http://resolver.tudelft.nl/uuid:05387c30-37ea-4fe6-b82a-b6ee3d7b73ec","Effect of pinholes in Nb4C3 MXene sheets on its electrochemical behavior in aqueous electrolytes","Zhao, Shuangshuang (Jilin University; Drexel University; South China Normal University); Wang, Xuehang (TU Delft RST/Storage of Electrochemical Energy; Drexel University); Kurra, Narendra (Drexel University; Indian Institute of Technology Hyderabad); Gogotsi, Yury (Drexel University); Gao, Yu (Jilin University)","","2022","Two-dimensional (2D) niobium carbide, Nb4C3Tx (Tx: O, OH, and F), a representative member of the 43 MXene structural motif, has shown promising electrochemical performance in acidic electrolytes. The capacitive performance of Nb4C3Tx in neutral aqueous electrolytes has been reported as moderate, but little effort has been made to improve it. In this paper, we report a method to introduce nanopores (pinholes) in Nb4C3Tx MXene flakes by adjusting the etching time. The pinholes generated during the etching process improve ion diffusion pathways, which are otherwise hindered by the restacking of the 2D flakes. The “holey Nb4C3Tx” shows a 50 % improved rate capability at charge/discharge time scales of 1–2 s in 1 M Li2SO4, Na2SO4, and (NH4)2SO4 electrolytes. Our strategy of controlling the permeability of Nb4C3Tx sheets can potentially be applied to other MXenes, providing guidance for improving the capacitance and rate capability of 2D materials.","Aqueous electrolyte; MXene; Niobium Carbide; Porous film; Supercapacitor","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:b051a5b8-e734-48b4-afc7-fbc9184396d0","http://resolver.tudelft.nl/uuid:b051a5b8-e734-48b4-afc7-fbc9184396d0","DEKS: A Secure Cloud-Based Searchable Service Can Make Attackers Pay","Zheng, Yubo (Huazhong University of Science and Technology); Xu, Peng (Huazhong University of Science and Technology); Wang, Wei (Huazhong University of Science and Technology); Chen, Tianyang (Huazhong University of Science and Technology); Susilo, Willy (University of Wollongong); Liang, K. (TU Delft Cyber Security); Jin, Hai (Huazhong University of Science and Technology)","Atluri, Vijayalakshmi (editor); Di Pietro, Roberto (editor); Jensen, Christian D. (editor); Meng, Weizhi (editor)","2022","Many practical secure systems have been designed to prevent real-world attacks via maximizing the attacking cost so as to reduce attack intentions. Inspired by this philosophy, we propose a new concept named delay encryption with keyword search (DEKS) to resist the notorious keyword guessing attack (KGA), in the context of secure cloud-based searchable services. Avoiding the use of complex (and unreasonable) assumptions, as compared to existing works, DEKS optionally leverages a catalyst that enables one (e.g., a valid data user) to easily execute encryption; without the catalyst, any unauthenticated system insiders and outsiders take severe time consumption on encryption. By this, DEKS can overwhelm a KGA attacker in the encryption stage before it obtains any advantage. We leverage the repeated squaring function, which is the core building block of our design, to construct the first DEKS instance. The experimental results show that DEKS is practical in thwarting KGA for both small and large-scale datasets. For example, in the Wikipedia, a KGA attacker averagely takes 7.23 years to break DEKS when the delay parameter T= 2 24. The parameter T can be flexibly adjusted based on practical needs, and theoretically, its upper bound is infinite.","Delay encryption with keyword search; Keyword guessing attack; Privacy; Security","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Cyber Security","","",""
"uuid:e088c64a-18a9-46aa-a232-d5d27bd04486","http://resolver.tudelft.nl/uuid:e088c64a-18a9-46aa-a232-d5d27bd04486","Default Prediction Using Network Based Features","Poenaru-Olaru, L. (TU Delft Data-Intensive Systems); Redi, Judith (Miro); Hovanesyan, Artur (Exact Software); Wang, H. (TU Delft Multimedia Computing)","Benito, Rosa Maria (editor); Cherifi, Chantal (editor); Cherifi, Hocine (editor); Moro, Esteban (editor); Rocha, Luis M. (editor); Sales-Pardo, Marta (editor)","2022","Small and medium enterprises (SME) are crucial for economy and have a higher exposure rate to default than large corporates. In this work, we address the problem of predicting the default of an SME. Default prediction models typically only consider the previous financial situation of each analysed company. Thus, they do not take into account the interactions between companies, which could be insightful as SMEs live in a supply chain ecosystem in which they constantly do business with each other. Thereby, we present a novel method to improve traditional default prediction models by incorporating information about the insolvency situation of customers and suppliers of a given SME, using a graph-based representation of SME supply chains. We analyze its performance and illustrate how this proposed solution outperforms the traditional default prediction approaches.","Default prediction; Network centrality; Network features; Network-based models; Transactional network","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Data-Intensive Systems","","",""
"uuid:510e4f10-34c4-466a-bb1f-c161a52d87c6","http://resolver.tudelft.nl/uuid:510e4f10-34c4-466a-bb1f-c161a52d87c6","Markov Modulated Process to Model Human Mobility","Chang, Brian (Student TU Delft); Yang, Liufei (Student TU Delft); Sensi, M. (TU Delft Network Architectures and Services); Achterberg, M.A. (TU Delft Network Architectures and Services); Wang, F. (TU Delft Network Architectures and Services); Rinaldi, M. (TU Delft Transport and Planning); Van Mieghem, P.F.A. (TU Delft Network Architectures and Services)","Benito, Rosa Maria (editor); Cherifi, Chantal (editor); Cherifi, Hocine (editor); Moro, Esteban (editor); Rocha, Luis M. (editor); Sales-Pardo, Marta (editor)","2022","We introduce a Markov Modulated Process (MMP) to describe human mobility. We represent the mobility process as a time-varying graph, where a link specifies a connection between two nodes (humans) at any discrete time step. Each state of the Markov chain encodes a certain modification to the original graph. We show that our MMP model successfully captures the main features of a random mobility simulator, in which nodes moves in a square region. We apply our MMP model to human mobility, measured in a library.","Human mobility; Markov chains; Markov modulated process; Modeling; Time-varying networks","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-02-01","","","Network Architectures and Services","","",""
"uuid:06de7915-6fa6-4012-b7ec-248e6ad880de","http://resolver.tudelft.nl/uuid:06de7915-6fa6-4012-b7ec-248e6ad880de","Lighter is Better: A Lighter Multi-client Verifiable Outsourced Computation with Hybrid Homomorphic Encryption","Wang, Xingkai (Shanghai Jiao Tong University); Cao, Zhenfu (East China Normal University); LIU, Z. (Shanghai Jiao Tong University; Shanghai Qizhi Institute, Shanghai); Liang, K. (TU Delft Cyber Security)","Atluri, Vijayalakshmi (editor); Di Pietro, Roberto (editor); Jensen, Christian D. (editor); Meng, Weizhi (editor)","2022","Gordon et al. (TCC 2015) systematically studied the security of Multi-client Verifiable Computation (MVC), in which a set of computationally-weak clients outsource the computation of a general function f over their private inputs to an untrusted server. They introduced the universally composable (UC) security of MVC and proposed a scheme achieving UC-security, where the protocol remains secure after arbitrarily composed with other UC-secure instances. However, the clients in their scheme have to undertake the heavy computation overhead caused by fully homomorphic encryption (FHE) and further, the plaintext size is linear to the function input size. In this work, we propose a more efficient UC-secure multi-client privacy-preserving verifiable computation protocol, called MVOC, that sharply reduces amortized overheads for clients, in both semi-honest and malicious settings. In particular, our protocol achieves stronger outsourcability by outsourcing more computation to the server, so that it may be more friendly to those lightweight clients. More specifically, we revisit the definition of garbling scheme, and propose a novel garbled circuit protocol whose circuit randomness is non-interactively provided by multiple parties. We also realize the idea of hybrid homomorphic encryption, which makes the FHE plaintext size independent of the input size. We present the detailed proof and analyze the theoretical complexity of MVOC. We further implement our protocol and evaluate the performance, and the results show that, after adopting our new techniques, the computation and communication overheads during input phase can be decreased by 55.15%–68.05% and 62.55%–75% respectively.","Hybrid homomorphic encryption; Outsourced computation; Verifiable computation","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Cyber Security","","",""
"uuid:828dd13b-2d57-4e96-b770-41b4b5c715ea","http://resolver.tudelft.nl/uuid:828dd13b-2d57-4e96-b770-41b4b5c715ea","Federated Learning With Heterogeneity-Aware Probabilistic Synchronous Parallel on Edge","Zhao, Jianxin (Beijing Institute of Technology); Han, Rui (Beijing Institute of Technology); Yang, Yongkai (Beijing Engineering Research Center of Civil Aviation Big Data; Key Laboratory of Intelligent Passenger Service of Civil Aviation-CAAC); Catterall, Benjamin (University of Cambridge); Liu, Chi Harold (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Data-Intensive Systems); Mortier, Richard (University of Cambridge); Crowcroft, Jon (University of Cambridge); Wang, Liang (University of Cambridge)","","2022","With the massive amount of data generated from mobile devices and the increase of computing power of edge devices, the paradigm of Federated Learning has attracted great momentum. In federated learning, distributed and heterogeneous nodes collaborate to learn model parameters. However, while providing benefits such as privacy by design and reduced latency, the heterogeneous network present challenges to the synchronisation methods, or barrier control methods, used in training, regarding system progress and model convergence etc. The design of these barrier mechanisms is critical for the performance and scalability of federated learning systems. We propose a new barrier control technique called Probabilistic Synchronous Parallel (PSP). In contrast to existing mechanisms, it introduces a sampling primitive that composes with existing barrier control mechanisms to produce a family of mechanisms with improved convergence speed and scalability. Our proposal is supported with a convergence analysis of PSP-based SGD algorithm. In practice, we also propose heuristic techniques that further improve the efficiency of PSP. We evaluate the performance of proposed methods using the federated learning specific FEMNSIT dataset. The evaluation results show that PSP can effectively achieve good balance between system efficiency and model accuracy, mitigating the challenge of heterogeneity in federated learning.","Federated learning; edge computing; distributed computing; barrier control","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Data-Intensive Systems","","",""
"uuid:ea16ce19-e4bc-482c-a6a8-debaa300d150","http://resolver.tudelft.nl/uuid:ea16ce19-e4bc-482c-a6a8-debaa300d150","Prior-Guided Deep Interference Mitigation for FMCW Radars","Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Li, Runlong (Beijing University of Posts and Telecommunications); He, Yuan (Beijing University of Posts and Telecommunications); Yang, Yang (Tianjin University)","","2022","In this article, the interference mitigation (IM) problem is tackled as a regression problem. A prior-guided deep learning (DL)-based IM approach is proposed for frequency-modulated continuous-wave (FMCW) radars. Considering the complex-valued nature of radar signals, a complex-valued convolutional neural network, which is different from the conventional real-valued counterparts, is utilized as an architecture for implementation. Meanwhile, as the desired beat signals of FMCW radars and interferences exhibit different distributions in the time–frequency domain, this prior feature is exploited as a regularization term to avoid overfitting of the learned representation. The effectiveness and accuracy of our proposed complex-valued fully convolutional network (CV-FCN)-based IM approach are verified and analyzed through both simulated and measured radar signals. Compared with the real-valued counterparts, the CV-FCN shows a better IM performance with a potential of half memory reduction in low signal-to-interference-plus-noise ratio (SINR) scenarios. The average SINR of interfered signals has been improved from −9.13 to 10.46 dB. Moreover, the CV-FCN trained using only simulated data can be directly utilized for IM in various measured radar signals and shows a superior generalization capability. Furthermore, by incorporating the prior feature, the CV-FCN trained on only 1/8 of the full data achieves comparable performance as that on the full dataset in low SINR scenarios, and the training procedure converges faster.","Complex-valued convolutional neural network (CNN); deep learning (DL); frequency-modulated continuous wave (FMCW); interference mitigation (IM); prior feature","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Microwave Sensing, Signals & Systems","","",""
"uuid:057dfa44-ae59-4312-a17e-7a148b7828da","http://resolver.tudelft.nl/uuid:057dfa44-ae59-4312-a17e-7a148b7828da","Tensile characterization and constitutive modeling of sintered nano-silver particles over a range of strain rates and temperatures","Qian, Cheng (Fudan University); Gu, Tijian (Hohai University); Wang, Ping (Hohai University); Cai, Wei (Hohai University); Fan, Xuejun (Lamar University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Fan, J. (TU Delft Electronic Components, Technology and Materials; Fudan University; Research Institute of Fudan University, Ningbo; Lamar University)","","2022","Sintered nano-silver die-attach materials have been widely used in high-power electronics packaging because of their high thermal and electrical conductivities. In this study, we characterized the tensile properties of sintered nano-silver particles over a range of strain rates and temperatures, and established the constitutive models. First, 50 nm nano-silver particles were sintered at 275 °C for 50 min as test samples, and their tensile tests were conducted under a dynamic thermomechanical analyzer (DMA Q800) and an IBTC 300SL in-situ mechanical test system respectively with different strain rates and ambient temperatures. Then, both Anand and variable-order fractional models (VoFM) were adopted to analyze the obtained stress-strain data and we studied their fitting accuracy and applicability. The results showed that: (1) The Young's modulus of the sintered nano-silver particles decreased with increasing temperature. In addition, the tensile strengths declined under lower strain rates and higher temperature conditions; (2) both the Anand model and VoFM characterized the tensile stress-strain properties of the sintered nano-silver material well. Compared to the Anand model, the VoFM utilized a simpler formula with fewer parameters and higher precision.","Power electronics packaging; Nano-silver sintering; Constitutive model; Anand model; Variable-order fractional model","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Components, Technology and Materials","","",""
"uuid:ff096452-d159-4e54-bd91-7833c6e2d06c","http://resolver.tudelft.nl/uuid:ff096452-d159-4e54-bd91-7833c6e2d06c","Systematic decomposition of sequence determinants governing CRISPR/Cas9 specificity","Fu, Rongjie (The University of Texas MD Anderson Cancer Center); He, Wei (The University of Texas MD Anderson Cancer Center); Dou, Jinzhuang (The University of Texas MD Anderson Cancer Center); Villarreal, Oscar D. (The University of Texas MD Anderson Cancer Center); Bedford, Ella (The University of Texas MD Anderson Cancer Center); Wang, Helen (The University of Texas MD Anderson Cancer Center); Hou, Connie (The University of Texas MD Anderson Cancer Center); Zhang, Liang (The University of Texas MD Anderson Cancer Center); Depken, S.M. (TU Delft BN/Bionanoscience; Kavli institute of nanoscience Delft)","","2022","The specificity of CRISPR/Cas9 genome editing is largely determined by the sequences of guide RNA (gRNA) and the targeted DNA, yet the sequence-dependent rules underlying off-target effects are not fully understood. To systematically explore the sequence determinants governing CRISPR/Cas9 specificity, here we describe a dual-target system to measure the relative cleavage rate between off- and on-target sequences (off-on ratios) of 1902 gRNAs on 13,314 synthetic target sequences, and reveal a set of sequence rules involving 2 factors in off-targeting: 1) a guide-intrinsic mismatch tolerance (GMT) independent of the mismatch context; 2) an “epistasis-like” combinatorial effect of multiple mismatches, which are associated with the free-energy landscape in R-loop formation and are explainable by a multi-state kinetic model. These sequence rules lead to the development of MOFF, a model-based predictor of Cas9-mediated off-target effects. Moreover, the “epistasis-like” combinatorial effect suggests a strategy of allele-specific genome editing using mismatched guides. With the aid of MOFF prediction, this strategy significantly improves the selectivity and expands the application domain of Cas9-based allele-specific editing, as tested in a high-throughput allele-editing screen on 18 cancer hotspot mutations.","","en","journal article","","","","","","","","","","BN/Bionanoscience","","","",""
"uuid:3cc141f9-8cc1-457b-8426-d189cf3a3386","http://resolver.tudelft.nl/uuid:3cc141f9-8cc1-457b-8426-d189cf3a3386","Design-Relevant Factors Affecting the Patient Experience in Digital Health: Preliminary Results of an Umbrella Systematic Review","Wang, T. (TU Delft Applied Ergonomics and Design); Giunti, Guido (TU Delft Applied Ergonomics and Design; University of Oulu); Melles, M. (TU Delft Applied Ergonomics and Design); Goossens, R.H.M. (TU Delft Human-Centered Design; TU Delft Applied Ergonomics and Design)","Otero, Paula (editor); Scott, Philip (editor); Martin, Susan Z. (editor); Huesing, Elaine (editor)","2022","Since Covid-19, digital health interventions (DHIs) have been embraced as never before. The pandemic led to many new challenges, including the patient experience in digital health care delivery. In this literature study, we identified and synthesized factors that impact patient experience in digital health (dPEx), and reviewed the methods and strategies relevant to its design and implementation. We conducted an umbrella review including 15 reviews representing 543 studies. Four themes were identified that describe design-relevant factors that impact dPEx: individual context, content, technical issues, and design features. We propose a preliminary framework to explain the relationship between each factor and support user-centered design efforts. Further research is needed to identify which factors have the most impact.","Quality Improvement; Telemedicine; User-centered Design","en","conference paper","IOS Press","","","","","","","","","Human-Centered Design","Applied Ergonomics and Design","","",""
"uuid:abedaa79-505a-4d94-bbf3-633a2e9f6599","http://resolver.tudelft.nl/uuid:abedaa79-505a-4d94-bbf3-633a2e9f6599","Alluvial Stratigraphic Response to Astronomical Climate Change: Numerical modelling and outcrop study in the Bighorn Basin, Wyoming, USA","Wang, Y. (TU Delft Applied Geology)","Martinius, A.W. (promotor); Abels, H.A. (copromotor); Delft University of Technology (degree granting institution)","2021","Alluvial stratigraphy is influenced by both allogenic and autogenic factors, which are difficult to be distinguished from each other because they operate at overlapping spatial and temporal scales. Moreover, it remains uncertain whether autogenic dynamics can result in sedimentary cyclicity that resembles allogenically-driven stratigraphic products. In order to undertake this challenge and address the uncertainty, we first test what sedimentary processes can produce the alluvial cyclicity observed in outcrops by designing comparable scenarios in the process-based numerical modelling. In the meantime, we systematically characterize floodplain aggradation cycles by tracing them in a UAV-based photogrammetric model. Moreover, we comprehensively describe channelized sandstone bodies in the field and the model to reconstruct the paleogeography. Lastly, we configure the relationships between floodplain aggradation cycles and sandstone bodies of different river styles, based on which we identify the link between orbital forcing and alluvial stratigraphic response.","Alluvial; Orbital forcing; Bighorn Basin; Numerical modelling","en","doctoral thesis","","978-94-6384-262-4","","","","","","","","","Applied Geology","","",""
"uuid:8fa25bbb-a024-4769-b90e-a4907c9366f0","http://resolver.tudelft.nl/uuid:8fa25bbb-a024-4769-b90e-a4907c9366f0","Case-driven category analysis of 3D building property","Ying, Shen (Wuhan University); Sun, Hanrui (Wuhan University); Li, Chengpeng (Wuhan University); Zhang, Wenting (Wuhan University); Wang, Meng (Wuhan University); Zhan, Yong (Chongqing Survey Institute); Zhang, Yu (Guangzhou Urban Planning Survey Design & Research Institute); Chen, Xueye (Key Laboratory of Urban Land Resources Monitoring and Simulation)","","2021","Many immigrants from rural areas pour into urban areas, especially in China, and urban development faces the challenges to provide sufficient space for citizens’ acommodation, works and social contacts. So 3D development and use of land and city space become the reality with various complex buildings and constructions with modern architecture and construction techniques. Many underground constructions like mall and subway with stations are built without clear impression comparing to the above reality scenes. Also many buildings above the earth surface show their special characters with either air building / overpass / viadust or “strange” shapes getting our attentions; but actually they bring new challenges of spatial management to handle the 3D property unit, either in describing their relations with reference to earth surface or in performing administrative processes in transactions of planning, approval and management. From the real cases of buildings or 3D property, this paper first details the relations between 3D properties and earth surface, the relative location relations between 3D building properties and earth surface form, and the correspondence between 3D building properties and surface parcel, then classifies the category according to these three profiles, which would promote the understandings of complex buildings and 3D building properties and would enhance the descriptions and the segmentation of 3D building properties.","spatial relationship; 3D cadastre; building property; ground level; earth surface; location","en","conference paper","","","","","","","","","","","","","",""
"uuid:1b81527f-c493-482c-af9f-cd46adb32729","http://resolver.tudelft.nl/uuid:1b81527f-c493-482c-af9f-cd46adb32729","Graphene-based neuromorphic computing: Artificial spiking neural networks","Wang, H. (TU Delft Computer Engineering)","Cotofana, S.D. (promotor); Wong, J.S.S.M. (promotor); Delft University of Technology (degree granting institution)","2021","The human brain is a natural high-performance computing systemwith outstanding properties, e.g., ultra-low energy consumption, highly parallel information processing, suitability for solving complex tasks, and robustness. As such, numerous attempts have been made to devise neuromorphic systems able to achieve brain-akin computation abilities, which can aid in understanding the complex human brain functionality and can be utilized to solve complex problems, e.g., pattern recognition and data mining. However, the fact that human brain comprises billions of neurons, which are the fundamental information processing units, and trillions of synapses that interconnect them makes the design and implementation of large-scale brain-inspired computing systems quite a challenging task. Graphene appears to be a promising candidate for scalable neuromorphic implementations as it exhibits a wealth of outstanding properties, e.g., ballistic transport, ultimate thinness, flexibility, and graphene devices are capable of emulating complex nonlinear functions and can be readily tuned to provide various conduction dynamicswhile preserving low energy operation and small footprint. Moreover, graphene is biocompatible, which offers perspectives for graphene-based neuromorphic bio-interfaces. This thesis aims to investigate graphene’s potential to enable scalable and energy effective neuromorphic computing. To this end, we first introduce an atomistic-level simulation model for calculating graphene electronic transport properties, that captures the hysteresis effects induced by interface charges trapping/detrapping phenomena. Second, we propose a generic graphene based synapse, which can be tailored to emulate different synaptic plasticity types by properly modifying its Graphene NanoRibbon (GNR) shape and contacts topology, as well as applying external voltages. Subsequently, we introduce a compact graphene-based integrate-and-fire spiking neuron that mimics the basic spiking neuronal dynamics. We further propose a basic SpikingNeuralNetwork (SNN) unit,which can be utilized to implement complex graphene-based SNNstructures. Finally,we introduce a reconfigurable graphene-based SNN architecture and a training methodology for obtaining the initial SNN synaptic weight values. We demonstrate the feasibility of the synaptic weights training methodology and the practical capabilities of the proposedSNNarchitecture by applying them to solve character recognition and edge detection problems. Our experiments clearly indicate that the proposed graphene-based neuromorphic approach enables lowenergy operation at small chip real estate footprint, which are enabling factors for the realization of scalable energy-efficient SNN implementations.","Neuromorphic Computing; Graphene; Spiking Neural Network; Synaptic Plasticity; Spiking Neuron","en","doctoral thesis","","978-94-6384-265-5","","","","","","","","","Computer Engineering","","",""
"uuid:36295f09-923e-4c89-aecc-55994deb2e65","http://resolver.tudelft.nl/uuid:36295f09-923e-4c89-aecc-55994deb2e65","Crumb rubber modified bitumen: Experimental characterization and modelling","Wang, H. (TU Delft Pavement Engineering)","Erkens, S. (promotor); Scarpas, Athanasios (promotor); Liu, X. (copromotor); Delft University of Technology (degree granting institution)","2021","A sustainable pavement, which can minimize environmental impacts through the reduction of energy consumption, natural resources and associated emissions while meeting all performance conditions and standards, is in urgent need to combat the climate change. The current scenario of depleting crude oil, reduced quarry zones, and stringent environmental regulations has driven the use of waste materials and by-products in pavement applications. The utilization of crumb rubber from scrap tires for bitumen modification has become a common engineering practice since last century...
Big mobility data vs. traditional travel survey data has been a topic of long-time debate in human mobility and travel behavior research. Big data are intuitively better but this is not always the case. Big mobility data relate to a large number of travelers and trips but little is known about each individual individual traveler and trip, not to mention that sometimes their information has to be aggregated for privacy concerns. On the other hand, travel survey data, despite reporting only a small group of respondents, tend to include abundant features about each individual traveler, such as age and attitudes, and each trip, such as trip purpose. Assuming that each row represents one traveler and each column represents one feature, big mobility data should have been described as long and thin, and “small” survey data (Chen et al., 2016) as short and wide.","","en","doctoral thesis","","978-90-5584-293-3","","","","","","","","","Transport and Planning","","",""
"uuid:477007fb-bfa5-4284-8705-b7644cc0b248","http://resolver.tudelft.nl/uuid:477007fb-bfa5-4284-8705-b7644cc0b248","Towards Personalised Dementia Care: Approaches, Recommendations and Tools from Design","Wang, G. (TU Delft Applied Ergonomics and Design)","Delft University of Technology (degree granting institution)","2021","According to Person-Centred Care, as far as possible, people with dementia should be cared for in a way that takes into account their personality, life experiences and preferences. Personalisation is hence the core of Person-Centred Care, yet the approaches, recommendations and tools are lacking for this purpose. Therefore, the author investigated how this personalisation could be facilitated by design. Specifically, the author explored how to personalise the care for Behavioural and Psychosocial Symptoms of Dementia (BPSD). This is because BPSD contributes to the most stressful, complex, and costly aspects of dementia care. Non-pharmacological interventions for BPSD care have been developed, which offers ample room for personalisation. From the field of healthcare, the author drew on Person-Centred Care, and from there, she looked at BPSD from the lens of the Need-driven Dementia-compromised Behaviour (NDB) model, where BPSD is interpreted as a way for people with dementia to express their unmet needs. Factors contributing to BPSD have been categorised by this model, which could be unique for each person with dementia. From the field of design, she approached the challenge from the lens of Human-Centered Design and explored three design approaches that are most relevant in designing for personalised BPSD care, namely, Ergonomics in Ageing, Co-design and Data-enabled Design. The author hypothesised that a combination of these three design approaches could reveal insights into the factors contributing to BPSD, as mentioned in the NDB model, for each person with dementia exhibiting BPSD symptoms. She further hypothesised that gaining insights about these factors could facilitate the design of personalised dementia care. The author implemented a series of steps in evaluating these hypotheses from the literature and from the field. The learnings gained throughout the literature and field research enabled the integration of the three design approaches into Knowme, a toolkit for designing for personalised dementia care. The author concludes with a summary of research findings, a reflection on the research approach, and ends with recommendations for future work.","Human-Centered Design; Dementia; Person-centred care; Ergonomics; Co-design; Data-enabled design; Design tools; Research through design; Personalisation; Personalised care","en","doctoral thesis","","978-94-6366-409-7","","","","","","","","","Applied Ergonomics and Design","","",""
"uuid:a7c34b83-8e01-4c54-a27b-bb202500abfd","http://resolver.tudelft.nl/uuid:a7c34b83-8e01-4c54-a27b-bb202500abfd","Data Assimilation in High Dimensional Systems Using Local Particle Filters: Overcoming the curse of dimensionality in hydrology","Wang, Z. (TU Delft Water Resources)","van de Giesen, N.C. (promotor); Hut, R.W. (copromotor); Delft University of Technology (degree granting institution)","2021","This dissertation's ultimate goal is to provide solutions to two problems that the promising data assimilation method, called the Particle Filter, has when applied to high dimensional non-linear models, such as those often used in hydrological research and forecasting. Two local particle filters have been proposed to overcome three major issues. Firstly, the curse of dimensionality caused by high dimensional models. Secondly, the uncertainty brought by the data assimilation method itself and finally the problem of nonlinearity in observation operators that link model states to observations. Both newly introduced data assimilation algorithms have been assessed using the Lorenz model (1996), a toy model that provides a perfect evaluation environment for such methods because it is a one-dimensional discrete chaotic model, which can simulate the behavior of changes of atmosphere. One local particle filter has been used in a practical application in hydrology to improve discharge accuracy in the Rhine river basin by assimilating satellite soil moisture into the PCR-GLOWB hydrological model.
The curse of dimensionality is well-known in particle filters. It happens in high dimensional models because, to remain accurate, the number of particles needs to increase exponentially with the increase of the model scale (ie. model dimension). One possible solution to avoid this curse is to apply localization in particle filters. Both proposed particle filters are based on a localization method. Uncertainty sources in data assimilation are many, and it is not easy to separate all of them clearly and directly. The two variants of the particle filter proposed in this thesis focus on different issues.
The localization used in the first particle filters divided the whole analysis of data assimilation into small batches for each model state. Each local analysis is independent, and it only assimilates observations within the localization scale. In the process it quantifies the uncertainty that is introduced by the data assimilation process itself. The localization method for the second local particle filter variant used another strategy. In its procedure, all observations are assimilated one by one, and each observation only affects near model states within the localization radius. When all observations are assimilated sequentially, all model states are updated. In addition, the second particle filter variant tried to solve the problem caused by nonlinear observation operators. To overcome the latter problems, the nonlinear observation operator was replaced by a surrogate model, named the Gaussian process regression model. For the calculation of the weights for each particle, model states needed to be transferred into the observation space. A Gaussian process regression surrogate model makes the transition process more straightforward in the nonlinear case because it provides the mean and standard deviation of estimates. Both local particle filter variants introduced in this thesis were evaluated thoroughly, and all results demonstrated that they performed satisfactorily in the specific nonlinear case and can be applied in high dimensional systems.
In addition to testing both local particle filters in the controlled Lorenz model, LPF-GT has also been verified as beneficial in a case study with the hydrological model PCR-GLOBWB. The specific study area focused on the Rhine river basin. The local particle filters have been applied to assimilate satellite soil moisture from the SMAP mission into the PCR-GLOBWB model to improve discharge estimates. Results show that the local particle filter performed well and significantly improved discharge accuracy by assimilating SMAP soil moisture. The new LPF-GT only requires a handful of particles to reach better performance in the Rhine river basin. This is particularly useful and practical for large-scale models that are often used in hydrology. Only requiring a small number of particles is the primary advantage of this data assimilation method because it saves lots of computational costs. In addition, the use of the localization in this particle filter makes the update for each model state independent from each other and can be conducted in parallel. Thus, the efficiency of this data assimilation method can be improved further.
In conclusion, the new additions to the particle filter proposed in this thesis are stable and can provide satisfying accuracy in nonlinear cases and for high dimensional models. Both of them have been proven to perform well in a toy model with many dimensions where they have direct value in solving the curse of dimensionality and nonlinearity. More importantly, they are valuable data assimilation methods to give direct insights into how to cope with uncertainty in nonlinear cases and to offer data assimilation frameworks for developing new particle filters in the future. The successful hydrological application of data assimilation using local particle filters in this research shows its considerable potential in hydrology.","Data Assimilation; Particle filters; Hydrology; Localization; PCR-GLOBWB 2.0 model; Satellite soil moisture","en","doctoral thesis","","978-94-6384-228-0","","","","","","2022-12-21","","","Water Resources","","",""
"uuid:79489c85-e9be-41ff-b79a-10d2b974fc94","http://resolver.tudelft.nl/uuid:79489c85-e9be-41ff-b79a-10d2b974fc94","Towards High Energy Density Anode-less Lithium Metal Batteries: A Study of Lithium Dendrites Suppression and Elimination","Wang, C. (TU Delft RST/Storage of Electrochemical Energy)","Wagemaker, M. (promotor); Brück, E.H. (promotor); Delft University of Technology (degree granting institution)","2021","Rechargeable Li-ion batteries for the market of electrical vehicles, portable equipment for entertainment, computing and telecommunication surge for the past decades, but the increasing demands introduce great challenges towards future battery systems that require higher energy and power density, improved safety as well as a longer lifespan. Lithium metal batteries can deliver higher energy densities compared with commercialized LIBs but the practical applications have been hindered due to the growth of lithium dendrites in liquid lithium metal batteries. The uncontrollable dendrite leads to the repeated formation of solid electrolyte interphase, irreversible capacity loss, short circuits, and safety hazards with liquid electrolytes. Compared to liquid electrolytes, solid-state electrolytes might be a better choice, but the reliance of ionic diffusion at the contact of solid particles is crucial presenting a major challenge. Moreover, the effective use of high capacity cathodes in combination with Li metal in a solid-state battery is another big challenge for future battery development. Therefore, to unlock the full potential of LMBs with high energy density and safe operation, it is imperative to devote efforts in solid-state batteries design. This thesis aims to search effective methods for enabling safe and high-energy-density solid-state Li metal batteries, starting from the developments of new concepts in liquid-based batteries and heading for an anode less Li metal solid-state battery configuration step by step.","Lithium metal batteries; high dielectric; dendrite suppression and elimination; high reversibility; high energy density","en","doctoral thesis","","978-94-6423-289-9","","","","","","2023-06-02","","","RST/Storage of Electrochemical Energy","","",""
"uuid:6bce32b4-a74b-4b13-8cdd-ad998b9ca268","http://resolver.tudelft.nl/uuid:6bce32b4-a74b-4b13-8cdd-ad998b9ca268","Influence of different corrosion solutions on reinforced concrete by DIC and traditional strain test","Wang, XiaoX (Southeast University, China); Liu, JiaP (Southeast University, China - State Key laboratory of High Performance Civil Engineering Materials, China); Zhong, PeiH (Southeast University, China)","","2021","When the corrosion expansion stress of the steel reinforcement exceeds the ultimate tensile strength of the concrete, the concrete will crack and eventually cause structural damage. Therefore, direct characterization methods of steel corrosion expansion stress can help predict the concrete cracking time, prevent corrosion expansion and repair the reinforcement concrete in advance. In this paper, by using the digital image correlation technology (DIC) to monitor the surface strain of concrete, and using the hollow steel bar to catch the strain of the steel bar under the condition of constant potential acceleration, the experiment and theory are established to characterized the relationship between the corrosion expansion stress and the concrete surface deformation. Besides, different corrosion solutions were applied to the specimens to investigate the effect of the corrosion solution on the corrosion rate of the steel bars in the concrete. The results show that the corrosion rate is seawater > 3% NaCl solution > 3% NaCl + 5% Na2SO4 composite solution. Among them, sulfate ions inhibited the promotion of chloride ions corroding on steel bars to a certain extent.","DIC; Reinforced concrete; Corrosion; Corrosion expansion stress","en","conference paper","","","","","","","","","","","","","",""
"uuid:e7b360c1-fdb9-47c5-8f2f-486da3b44796","http://resolver.tudelft.nl/uuid:e7b360c1-fdb9-47c5-8f2f-486da3b44796","Strain hardening behaviour of PVA fibre reinforced geopolymer composites","Wang, Yi (University College London, UK); Zhang, Mingzhong (University College London, UK)","","2021","Strain hardening geopolymer composites (SHGC) as a tailored group of fibre reinforced geopolymer composites are featured by large tensile strain capacity with multiple micro-cracks. This paper experimentally investigates the strain hardening behaviour of SHGC in terms of flexural stress-deflection response, failure mode and cracking, flexural strength and toughening mechanisms. SHGC specimens were prepared using fly ash and slag with a weight ratio of 80:20 as the binder, a combination of NaOH and Na2SiO3 as the alkaline activator with the activator/binder ratio of 0.4. The effects of PVA fibre content (0, 1%, 1.5%, and 2%) and microsilica sand content (0, 10%, 20%, 30%, and 40%) on strain hardening behaviour of SHGC specimens were estimated. The toughening mechanisms (fibre bridging, rupture, and pull-out) and features of micro-cracks (number and width) distributed over the tensile side of specimens under four-point bending were characterised using digital microscope. Results indicate that all fibre reinforced specimens exhibited strain hardening behaviour with large deflection and multiple micro-cracks. The addition of PVA fibres up to 2% improved the strain hardening behaviour of SHGC and increased the flexural strength by 126% compared to SHGC specimen without fibre because of fibre bridging effect. The incorporation of microsilica sand up to 20% enhanced the flexural strength by 38.3% but further adding sand to 40% reduced the flexural strength of SHGC specimens. Overall, the SHGC specimen containing 2% PVA fibre and 20% micro-silica sand achieved the optimum strain hardening behaviour.","Toughness; Alkali-activated materials; Engineered geopolymer composites; Fibre reinforced concrete; Flexural behaviour","en","conference paper","","","","","","","","","","","","","",""
"uuid:ab28866f-c857-42a5-a613-2d95566b9898","http://resolver.tudelft.nl/uuid:ab28866f-c857-42a5-a613-2d95566b9898","Effect of early strength agent on cement slurry containing retarder","Wang, Liguo (Southeast University, China); Ju, Siyi (Southeast University, China); Wang, Lanxin (Southeast University, China); Jiang, Jinyang (Southeast University, China)","","2021","Retarders have an important regulation effect on the hydration speed and setting time of cement. However, retarders are not conducive to the early strength development of concrete, so use early strength agents to improve their early performance. In this paper, the effects of different amounts of triethanolamine (TEA) and citric acid (CA) on the hydration dynamics and mechanical properties of silicate cement were investigated. The results showed that, as the CA content increases, the setting time of the cement slurry can be effectively prolonged. And the right amount of TEA can not only make the cement reach the early strength, but also increase the compressive strength in the later stage, and control the setting time of the cement paste. TEA shortens the induction period of CA-incorporated cement and increases the heat release rate during cement hydration induction period.","mechanical properties; Retarders; early strength agents; hydration dynamics","en","conference paper","","","","","","","","","","","","","",""
"uuid:eee716ea-f4f6-4a70-b867-c91a3904612d","http://resolver.tudelft.nl/uuid:eee716ea-f4f6-4a70-b867-c91a3904612d","Effect of ultra-fine fly ash on the mechanical and shrinkage properties of ultra-high performance concrete","Feng, Taotao (Southeast University, China); Jiang, Jinyang (Southeast University, China); Chu, Hongyan (Nanjing Forestry University, China); Wang, Liguo (Southeast University, China)","","2021","This paper reports on a study to determine the possibility of using ultra-fine fly ash (UFA) for partial or total replacement of normal fly ash (NFA) in ultra-high performance concrete (UHPC). Workability, microstructure, porosity, drying shrinkage as well as mechanical properties were comprehensively studied to investigate the influence of UFA on UHPC. The fly ash, which was a compound of NFA and UFA with various mass fractions, had a total content of 30 wt%. The results demonstrated that compressive strength is enhanced if NFA is partially or totally replaced with UFA. Compared to the reference mixture containing 100 wt% NFA, incorporating UFA into UHPC has been shown to improve its workability. Contrarily, adverse effects on drying shrinkage were discovered when NFA is substituted with UFA.","drying shrinkage; Ultra-fine fly ash; ultra-high performance concrete; compressive strength","en","conference paper","","","","","","","","","","","","","",""
"uuid:aa66d0a5-75e0-48e5-ae80-f438a5ad91de","http://resolver.tudelft.nl/uuid:aa66d0a5-75e0-48e5-ae80-f438a5ad91de","Deterioration of organic coatings on concrete under artificial aging","Wang, Haochuan (Southeast University, China); Feng, Pan (Southeast University, China - State Key Laboratory of High Performance Civil Engineering Materials, China); Geng, Zifan (Southeast University, China); Liu, Qi (Southeast University, China)","","2021","The deterioration of organic coatings on concrete is closely linked to the efficiency in the protection process of reinforced structures. In the present work, polyurea resin and epoxy resin, which are widely used engineering coatings, were selected to measure and compare the performance under artificial aging. Fourier Transform infrared spectroscopy, water contact angle and scanning electron microscope were used to determine the deterioration of coatings. X-ray fluorescence method was used to measure chloride content passing through the coatings, which represent the efficiency of protection. Test results demonstrate that both deterioration and resistance to corrosion are important in assessment of the organic coatings under aging.","efficiency; organic coating; concrete; artificial ageing","en","conference paper","","","","","","","","","","","","","",""
"uuid:aa027416-132c-46c9-a1eb-c8c06d6fdc0f","http://resolver.tudelft.nl/uuid:aa027416-132c-46c9-a1eb-c8c06d6fdc0f","A probabilistic approach for estimating corrosion possibility of reinforced concrete structure considering crack development","Wang, Tiao (The University of Tokyo,, Japan); Luan, Yao (Saitama University, Japan)","","2021","Reinforcement corrosion induced by chloride ingress is one of the major threats of reinforced concrete (RC) structures exposed to chloride attack. The cracks of concrete cover provide additional paths of chloride ingress and facilitate the reinforcement corrosion. Current information regarding the influence of crack development on corrosion possibility is insufficient due to lack of proper analytical approach. On this account, a rapid numerical approach (RNA) is developed in this study to study the chloride ingress of cracked concrete. It could consider the crack development and chloride biding effect. This approach is validated through comparisons with the FEM analysis. Based on this approach, it becomes feasible to estimate the corrosion possibility of cracked RC structures.","Corrosion possibility; Chloride content; Crack Development; Rapid numerical approach","en","conference paper","","","","","","","","","","","","","",""
"uuid:dd589aeb-aa7d-449a-885e-42b2f65c6096","http://resolver.tudelft.nl/uuid:dd589aeb-aa7d-449a-885e-42b2f65c6096","Unidirectional sulfate ingress in limestone calcined clay cement (LC3) pastes under cyclic exposure","Wang, Qiao (École Polytechnique Fédérale de Lausanne, Switzerland); Wilson, William (École Polytechnique Fédérale de Lausanne, Switzerland); Scrivener, Karen (École Polytechnique Fédérale de Lausanne, Switzerland)","","2021","If sulfate attack on Portland cement systems has been largely investigated in the last decades, mechanisms of sulfate resistance for systems with new SCMs are still in dim, especially for the emerging materials that are limestone calcined clay cements (LC³). Using a new semi-immersion approach, we forced the penetration of sulfate ions in just one direction into LC³ pastes under the capillary rise effect. To enhance the degradation process, highly concentrated sodium sulfate solution of 50 g/L and a cyclic exposure regime (20˚C & 78% RH followed by 40˚C & 33% RH) were employed in this paper. During exposure, lateral expansion was measured over time, showing almost negligible expansion for the LC³ cement paste even after 56 days of very harsh exposure conditions. Simultaneously, microanalytical studies on the composition of hydration products were carried out by SEM-mapping to explain the expansion mechanisms. The results showed that the novel approach was adequate for cyclic exposure experiments, to investigate the full depth of degradation along the penetrating direction. Based on the analysis of BSE micrographs, phase distribution maps and expansion profiles, the gypsum and the ettringite were found to coexist in the voids resulting in a densified layer which could be associated with the most expansive zone. Overall, this study highlights the potential of the unidirectional semi-immersed method to link the sulfate attack expansion of cement pastes with the underlying mechanisms.","Degradation; LC³; Sulfate attack; Unidirectional penetration; SEM","en","conference paper","","","","","","","","","","","","","",""
"uuid:8c441ff4-cf08-4d55-a9fc-fe07792129bd","http://resolver.tudelft.nl/uuid:8c441ff4-cf08-4d55-a9fc-fe07792129bd","Relationship between the water absorption and the chloride ion penetration of blended cement concrete with various SCMs: A preliminary evaluation on whether water absorption can provide a reliable estimation of other transport properties","Zhuang, Shiyu (Tsinghua University, China); Wang, Qiang (Tsinghua University, China)","","2021","Water absorption is an indicator of other transport properties and even durability of concrete since it provides a dominant invasion mechanism for the penetration of aggressive ions. Relationship between the water absorption and the chloride ion penetration of concrete containing fly ash, slag and silica fume at various water-to-binder ratios is investigated in this study. It is found that water absorption can provide a reliable estimation of chloride ion penetration. There is a good correspondence between the initial water absorption rate and the chloride ion penetration grade. The initial water absorption rate of more than 50×10-3 mm/s0.5, 40-30×10-3 mm/s0.5, 30-20×10-3 mm/s0.5 and less than 20×10-3 mm/s0.5 may correspond to the chloride ion penetration grade of “high”, “moderate”, “low” and “very low”, respectively. The initial water absorption rate can further reflect the transport property and durability of concrete in the same chloride ion penetration grade where the comparison of the specific charge passed values is invalid. Water absorption has the potentiality to act as a deterministic index for the transport properties and the durability of concrete.","supplementary cementitious material; transport property; durability; water absorption; chloride ion penetration","en","conference paper","","","","","","","","","","","","","",""
"uuid:abb4590c-2f21-4ea8-93f5-ba6f0fe9f874","http://resolver.tudelft.nl/uuid:abb4590c-2f21-4ea8-93f5-ba6f0fe9f874","Strength and microstructure of alkali-activated phosphorous slag binder: Effects of activator type/dosage and phosphorous slag chemical composition","Huang, Z. (Tsinghua University, China); Wang, Q (Tsinghua University, China)","","2021","In this paper, the influence of sodium hydroxide and water glass of various modulus, as activators, on the compressive strength, microstructure and hydration products of two alkali-activated phosphorous slag (AAPS) with different chemical composition were studied. Water glass activation shows relatively higher later compressive strength when the slag with a higher Ca content is activated. Phosphorous slag with higher Ca content shows a faster strength development. Heat evolution shows that the alkalinity of the paste determines the intensity of early reaction and the Si content of the paste determines the development of later reaction. X-ray diffraction depicts a well-organized crystal structure in both two phosphorous slags activated by sodium hydroxide. Hydrotalcite formation is also observed in these groups. The main hydration product C-S-H in alkali-activated phosphorous slag with higher Ca content exhibits a higher crystallinity due to the increase of paste’s alkalinity. 29Si and 27Al MAS NMR spectroscopy reveals that the alkalinity plays important role on the disorder of the product. The disorder of the product decreases with the increase of the alkalinity.","NMR; Phosphorous slag; Alkali-activated material; Isothermal calorimetry; XRD","en","conference paper","","","","","","","","","","","","","",""
"uuid:396f9a59-8288-49c5-8717-21267159e64d","http://resolver.tudelft.nl/uuid:396f9a59-8288-49c5-8717-21267159e64d","Effect of fine aggregate on rheological properties of ultra-high performance concrete(UHPC)","Ju, Siyi (Southeast University, China); Feng, Taotao (Southeast University, China); Wang, Liguo (Southeast University, China); Jiang, Jinyang (Southeast University, China)","","2021","In this paper, four kinds of ecological fine aggregates (manufactured sand, recycled sand, aeolian sand and river sand) were used to prepared UHPC, the effects of the fine aggregates on the workability, rheological properties and mechanical properties of UHPC were studied. The results reveal that the type and content of fine aggregate have an effect on the rheological properties and mechanical strength of UHPC. Under the same mix proportion, the yield stress and plastic viscosity of recycled sand UHPC are higher than those of river sand UHPC, manufactured sand UHPC and aeolian sand UHPC, mainly due to its high water absorption. The high intergranular porosity, high surface area and low fineness modulus of aeolian sand contributes to an increase in yield stress, and high rate into thin and irregular shapes of manufactured sand are the major ingredients which affect the workability of UHPC. The yield stress and plastic viscosity of UHPC decrease with the increase of water-binder ratio, and the gap between the four fine aggregate systems is gradually narrowed. The effects of different fine aggregates on the mechanical properties of UHPC are arranged according to the improvement effect: recycled sand > manufactured sand > river sand > aeolian sand.","plastic viscosity; Ultra-high performance concrete; workability; fine aggregate; yield stress","en","conference paper","","","","","","","","","","","","","",""
"uuid:6fb647c7-e262-4f7a-a370-e0e4800ec0fc","http://resolver.tudelft.nl/uuid:6fb647c7-e262-4f7a-a370-e0e4800ec0fc","Effect of CA bacteria on the carbonation process of γ-C2S","Jin, Peng (Southeast University, China); Wang, Ruixing (Southeast University, China); Zhang, Siyi (Southeast University, China); Dong, Hua (Southeast University, China); Chen, Chun (Southeast University, China)","","2021","Carbonation has been proven to be a promising way to improve the mechanism properties and durability of steel slag products. CA bacteria can promote the hydration of CO2. In this study, one kind of alkali-resistant CA bacteria was chosen to investigate its effects on the carbonation process of γ-C2S. Results showed that bacteria could increase the compressive strength of carbonized γ-C2S by 19.0%. Main products of carbonized γ-C2S were vaterite, calcite and SiO2 gel. The addition of bacteria could only accelerate the deposition of calcium carbonate, while hardly changing the types and properties of the carbonation products. Additionally, accelerated carbonation makes it harder for the carbon dioxide to diffuse inward, leading to the decline of accelerating carbonation effect. However, CA bacteria could change the morphology of calcium carbonated during the carbonation process of β-C2S and further accelerate the hydration process of β-C2S. The pore structure can also be refined with the incorporation of bacteria.","Pore Structure; γ-C2S; β-C2S; CA bacteria; Carbonation products","en","conference paper","","","","","","","","","","","","","",""
"uuid:da94c51f-fbce-4d9e-93d7-f2f74067e9c7","http://resolver.tudelft.nl/uuid:da94c51f-fbce-4d9e-93d7-f2f74067e9c7","Effect of reactive aggregate on the early age reaction of water-glass activated slag/fly ash mortars","Wang, Wei (The University of Tokyo, Japan); Zhang, Shizhe (Delft University of Technology, The Netherlands); Guang, Ye (Delft University of Technology, the Netherlands); Noguchi, Takafumi (The University of Tokyo, Japan)","","2021","Alkali activated materials (AAMs) have received worldwide attention due to its lower embodied energy and environmental impact than that of traditional cementitious materials. However, the activators with high alkalinity may raise the risk of alkali silica reaction (ASR) induced deterioration when reactive aggregates are used, which thereby limits the commercial use of AAMs. Not speaking the ASR induced long-term expansion, the early-age reaction of AAMs prepared with reactive aggregates is largely unknown. In this paper, isothermal calorimetry, thermogravimetry (TG) and mercury intrusion porosimetry (MIP) were adopted to study the heat evolution, mineralogical changes and pore structures of early-age ordinary Portland cement (OPC) mortar and water-glass activated slag/fly ash mortars. In each system, emphasis were made to understand the differences between mixtures prepared with standard inert quartz sands and reactive fine aggregates. The results show that the mortars prepared with reactive aggregates generated more heat in the wetting and dissolution stage. Particularly, the water-glass activated slag mortar presented the highest heat flow peak. Meanwhile, the results of TG illustrate that higher amount of reaction products were formed in water-glass activated mortars prepared with reactive aggregates than that with inert quartz sands. These findings suggest that the reactive aggregates are evidently involved in the early-age alkaline reaction of AAMs system.","Pore structure; Alkaline activation; lkali-silica reaction; Early-age; Heat evolution","en","conference paper","","","","","","","","","","","","","",""
"uuid:02e0026c-950a-4f64-8f81-64779ac808ea","http://resolver.tudelft.nl/uuid:02e0026c-950a-4f64-8f81-64779ac808ea","Characteristics of fly ash blended mortars under ammonium chloride solution leaching","Pang, Min (Tongji University, China); Sun, Zhenping (Tongji University, China); Ji, Yanliang (Tongji University, China); Yang, Jingbin (Tongji University, China); Wang, Peiming (Tongji University, China); Xu, Yaling (Shanghai Urban Construction Material Co., China); Li, Huanhuan (Shanghai Urban Construction Material Co., China); Liu, Jiaying (Shanghai Urban Construction Material Co., China); Li, Fei (Shanghai Fupei New Material Technology Co., China)","","2021","Characteristics of fly ash(FA) blended mortars (50%, 70% and 90%) at different curing ages (28 days and 180 days) under ammonium chloride solution(ACS) leaching were investigated. Mass loss under leaching, initial CaO content, Ca(OH)2 content(CH), content of chemical bonded water, and hydration degree of blended pastes were tested by XRF and DSC-TG. Based on correlations between initial CaO content and CH content in blended pastes, correlations between mass loss under leaching and initial CaO content were analyzed, as well as effects of hydration degree of blended pastes and chemical bonded water in blended pastes. Results showed that FA blended mortars experienced a mass-loss period along with immersion in ACS, either 28-day curing regime or 180-day curing regime, and FA could minimize this mass loss obviously. Effects of hydration degree of FA blended pastes on this mass loss were feeble, but remarkable fluctuations could be made by chemical bonded water of FA blended pastes. Effect of FA against ACS leaching should be owed to its pozzolanic reaction which might neutralize attacks from ACS. However, this effect of FA against ACS leaching would weaken as long as alkaline environment increasingly extinguished. Therefore, excessive dosages of FA should be careful for structures and buildings experiencing solution leaching attacks. According to correlations with mass loss under solution leaching attacks, characteristic of initial CaO content in FA blended pastes could be regarded as one effective evaluation against solution leaching attacks.","Ca(OH)2 contentmass loss under leaching; fly ash blended pastes; initial CaO content","en","conference paper","","","","","","","","","","","","","",""
"uuid:0d3dfcdd-a5c1-4696-84d9-389a8515a338","http://resolver.tudelft.nl/uuid:0d3dfcdd-a5c1-4696-84d9-389a8515a338","Effect of Unit-Cell Size on the Barely Visible Impact Damage in Woven Composites","El-Dessouky, Hassan M. (University of Sheffield; Galala University; Mansoura University); Saleh, M. (TU Delft Structural Integrity & Composites); Wang, Ying (The University of Manchester); Alotaibi, Mohamed S. (Galala University; Prince Sattam Bin Abdulaziz University)","","2021","The effect of the weaving architecture and the z-binding yarns, for 2D and 3D woven composites on the low-velocity impact resistance of carbon fibre reinforced composites, is investigated and benchmarked against noncrimp fabric (NCF). Four architectures, namely: NCF, 2D plain weave (2D-PW), 3D orthogonal: plain (ORT-PW) and twill (ORT-TW), were subjected to 15 J impact using a 16 mm-diameter, 6.7 kg hemispherical impactor. Nondestructive techniques, including ultrasonic C-scanning, Digital Image Correlation (DIC) and X-ray computed tomography (CT) were used to map and quantify the size of the induced barely visible impact damage (BVID). The energy absorption of each architecture was correlated to the damage size: both in-plane and in-depth directions. The 3D architectures, regardless of their unit-cell size, demonstrated the highest impact resistance as opposed to 2D-PW and the NCF. X-ray CT segmentation showed the effect of the higher frequency of the z-binding yarns, in the ORT-PW case, in delamination and crack arresting even when compared to the other 3D architecture (ORT-TW). Among all the architectures, ORT-PW exhibited the highest damage resistance with the least damage size. This suggests that accurate design of the z-binding yarns’ path and more importantly its frequency in 3D woven architectures is essential for impact-resistant composite structures.","3-dimensional reinforcement; Carbon fibre; Impact behaviour; Nondestructive testing; X-ray computed tomography","en","journal article","","","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:a5bdb2ef-c02c-45e9-bb92-07961d3ef28b","http://resolver.tudelft.nl/uuid:a5bdb2ef-c02c-45e9-bb92-07961d3ef28b","The impact of heterogeneity on geothermal production: simulation benchmarks and applications","Wang, Y. (TU Delft Reservoir Engineering)","Voskov, D.V. (promotor); Bruhn, D.F. (promotor); Delft University of Technology (degree granting institution)","2021","Numerical simulation plays an important role for the efficient development of geothermal resources, considering all the uncertain and sensitive parameters that exist within the subsurface and during the operations. This thesis describes the numerical modeling of geothermal developments of various types and in various situations using the newly developed open-source numerical simulator, called Delft Advanced Research Terra Simulator, shortly DARTS. The main objective of this thesis is to investigate the influence of heterogeneity to geothermal developments...","heterogeneous reservoir; geothermal benchmark; sensitivity analysis; uncertainty quantification; fractured reservoir","en","doctoral thesis","","978-94-6384-197-9","","","","","","","","","Reservoir Engineering","","",""
"uuid:a737a7c1-d0f8-47c0-ab09-f64043391ebf","http://resolver.tudelft.nl/uuid:a737a7c1-d0f8-47c0-ab09-f64043391ebf","A review of experimental and theoretical fracture characterization of bi-material bonded joints","Wang, W. (TU Delft Structural Integrity & Composites; Swiss Federal Laboratories for Materials Science and Technology (Empa)); Teixeira De Freitas, S. (TU Delft Structural Integrity & Composites); Poulis, J.A. (TU Delft Adhesion Institute); Zarouchas, D. (TU Delft Structural Integrity & Composites)","","2021","High performance structures require the use of different materials to meet their demanding requirements. Especially fibre reinforced polymer composites are nowadays often bonded to metals in order to take the most advantage of the materials properties and to minimize their disadvantages. However, the interface in such bi-material assemblies often represents the weakest point and thus has to be carefully addressed to ensure structural integrity. This review paper presents an overview of the research on bi-material interface crack problems over the past 30 years. Three categories of the research are discussed: mechanical testing, crack driving force and mode partitioning. The literature reveals that the key element to the fracture analysis of the bi-material interface crack is how to perform the mode partitioning. The proposed theories for mode partitioning by many researchers are meaningful yet underdeveloped and need further experimental validation.","Bi-material joints; Mixed-mode fracture; Mode partitioning; Specimen design","en","review","","","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:9d96e6e9-0203-46d1-9edd-1c8c4304571e","http://resolver.tudelft.nl/uuid:9d96e6e9-0203-46d1-9edd-1c8c4304571e","Your Smart Contracts Are Not Secure: Investigating Arbitrageurs and Oracle Manipulators in Ethereum","Tjiam, Kevin (Student TU Delft); Wang, R. (TU Delft Cyber Security); Chen, H. (TU Delft Cyber Security); Liang, K. (TU Delft Cyber Security)","","2021","Smart contracts on Ethereum enable billions of dollars to be transacted in a decentralized, transparent and trustless environment. However, adversaries lie await in the Dark Forest, waiting to exploit any and all smart contract vulnerabilities in order to extract profits from unsuspecting victims in this new financial system. As the blockchain space moves at a breakneck pace, exploits on smart contract vulnerabilities rapidly evolve, and existing research quickly becomes obsolete. It is imperative that smart contract developers stay up to date on the current most damaging vulnerabilities and countermeasures to ensure the security of users' funds, and to collectively ensure the future of Ethereum as a financial settlement layer. This research work focuses on two smart contract vulnerabilities: transaction-ordering dependency and oracle manipulation. Combined, these two vulnerabilities have been exploited to extract hundreds of millions of dollars from smart contracts in the past year (2020-2021). For each of them, this paper presents: (1) a literary survey from recent (as of 2021) formal and informal sources; (2) a reproducible experiment as code demonstrating the vulnerability and, where applicable, countermeasures to mitigate the vulnerability; and (3) analysis and discussion on proposed countermeasures. To conclude, strengths, weaknesses and trade-offs of these countermeasures are summarised, inspiring directions for future research.","arbitrageurs; ethereum; oracle manipulator; security; smart contract; vulnerability","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Cyber Security","","",""
"uuid:3f855d6b-9be2-4017-9cad-a9218bec10e3","http://resolver.tudelft.nl/uuid:3f855d6b-9be2-4017-9cad-a9218bec10e3","Graphene-Based Artificial Synapses with Tunable Plasticity","Wang, H. (TU Delft Computer Engineering); Cucu Laurenciu, N. (TU Delft Computer Engineering); Jiang, Y. (TU Delft Computer Engineering); Cotofana, S.D. (TU Delft Computer Engineering)","","2021","Design and implementation of artificial neuromorphic systems able to provide brain akin computation and/or bio-compatible interfacing ability are crucial for understanding the human brain's complex functionality and unleashing brain-inspired computation's full potential. To this end, the realization of energy-efficient, low-area, and bio-compatible artificial synapses, which sustain the signal transmission between neurons, is of particular interest for any large-scale neuromorphic system. Graphene is a prime candidate material with excellent electronic properties, atomic dimensions, and low-energy envelope perspectives, which was already proven effective for logic gates implementations. Furthermore, distinct from any other materials used in current artificial synapse implementations, graphene is biocompatible, which offers perspectives for neural interfaces. In view of this, we investigate the feasibility of graphene-based synapses to emulate various synaptic plasticity behaviors and look into their potential area and energy consumption for large-scale implementations. In this article, we propose a generic graphene-based synapse structure, which can emulate the fundamental synaptic functionalities, i.e., Spike-Timing-Dependent Plasticity (STDP) and Long-Term Plasticity. Additionally, the graphene synapse is programable by means of back-gate bias voltage and can exhibit both excitatory or inhibitory behavior. We investigate its capability to obtain different potentiation/depression time scale for STDP with identical synaptic weight change amplitude when the input spike duration varies. Our simulation results, for various synaptic plasticities, indicate that a maximum 30% synaptic weight change and potentiation/depression time scale range from [-1.5 ms, 1.1 ms to [-32.2 ms, 24.1 ms] are achievable. We further explore the effect of our proposal at the Spiking Neural Network (SNN) level by performing NEST-based simulations of a small SNN implemented with 5 leaky-integrate-and-fire neurons connected via graphene-based synapses. Our experiments indicate that the number of SNN firing events exhibits a strong connection with the synaptic plasticity type, and monotonously varies with respect to the input spike frequency. Moreover, for graphene-based Hebbian STDP and spike duration of 20ms we obtain an SNN behavior relatively similar with the one provided by the same SNN with biological STDP. The proposed graphene-based synapse requires a small area (max. 30 nm2), operates at low voltage (200 mV), and can emulate various plasticity types, which makes it an outstanding candidate for implementing large-scale brain-inspired computation systems.","Artificial synapse; graphene; LTD; LTP; neuromorphic computing; STDP; synaptic plasticity","en","journal article","","","","","","","","","","","Computer Engineering","","",""
"uuid:7bbd83a1-d4ea-414b-9ffc-2f3365c93caf","http://resolver.tudelft.nl/uuid:7bbd83a1-d4ea-414b-9ffc-2f3365c93caf","The Influence of Linear Permanent Magnet Generator Sizing on the Techno-Economic Performance of a Wave Energy Converter","Tan, J. (TU Delft Offshore and Dredging Engineering); Wang, X. (TU Delft Transport Engineering and Logistics); Jarquin Laguna, A. (TU Delft Offshore and Dredging Engineering); Polinder, H. (TU Delft Transport Engineering and Logistics); Miedema, S.A. (TU Delft Offshore and Dredging Engineering)","","2021","Downsizing the Power Take-off (PTO) rating has been proven to be beneficial for decreasing the Levelized Cost of Energy (LCOE) of wave energy converters (WECs). However, the linear permanent magnet (PM) generator has not yet been modelled and optimized in detail in previous feasibility studies. This paper extends the study of the PTO downsizing to further investigate the influence of the linear PM generator sizing on a WEC's techno-economic performance. The generator is sized for providing different maximum forces, and the effect of sizing on the generator performance is presented. The efficiency map of the selected linear generator design is applied to evaluate the annual energy production (AEP) and finally identify its influence on the techno-economic performance of a WEC.","Downsizing; Linear permanent magnet generator; Techno-economic performance; Wave energy converter","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-02-12","","","Offshore and Dredging Engineering","","",""
"uuid:9d70f19f-11c4-485b-a11a-4fbd792d7c10","http://resolver.tudelft.nl/uuid:9d70f19f-11c4-485b-a11a-4fbd792d7c10","A Delayed and Subsampled Wideband Sparse Array for Joint Angle and Frequency Estimation","Wang, F. (TU Delft Signal Processing Systems); Leus, G.J.T. (TU Delft Signal Processing Systems)","Matthews, Michael B. (editor)","2021","In this paper we consider the problem of joint wideband spectrum sensing and direction-of-arrival (DoA) estimation, where a number of uncorrelated narrowband sources spread over a wide frequency band impinge on a sparse linear array (SLA). To overcome the sampling rate bottleneck for wideband spectrum sensing, we rely on sub-Nyquist sampling for the receiver, and to resolve the sources both in the angle and frequency domain, an additional delayed branch is included for every antenna to gain an extra degree of freedom (DoF). Appropriately designing the delays at the different antennas allows us to use the contemporary machinery of co-array processing. We accordingly propose a joint eigenvalue decomposition (EVD) based algorithm to jointly estimate the angles and frequencies of the different sources with automatic pairing. Furthermore, as a consequence of the co-array processing, we can handle more sources than the number of physical antennas. Simulation results are included to corroborate our findings.","Wideband spectrum sensing; direction-of-arrival (DoA) estimation; sub-Nyquist sampling; sparse linear array (SLA); joint eigenvalue decomposition (EVD)","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-09-04","","","Signal Processing Systems","","",""
"uuid:51d90eb9-c6ee-46dc-80c2-c4bc70f7743a","http://resolver.tudelft.nl/uuid:51d90eb9-c6ee-46dc-80c2-c4bc70f7743a","A Markov Traffic Model for Signalized Traffic Networks Based on Bayesian Estimation","Liu, S. Y. (University of Chinese Academy of Sciences); Lin, S. (University of Chinese Academy of Sciences); Wang, Y. B. (Zhejiang University); De Schutter, B.H.K. (TU Delft Team Bart De Schutter); Lam, W. H.K. (The Hong Kong Polytechnic University)","","2021","In order to better understand the stochastic dynamic features of signalized traffic networks, we propose a Markov traffic model to simulate the dynamics of traffic link flow density for signalized urban traffic networks with demand uncertainty. In this model, we have four different state modes for the link according to different congestion levels of the link. Each link can only be in one of the four link state modes at any time, and the transition probability from one state to the other state is estimated by Bayesian estimation based on the distributions of the dynamic traffic flow densities, and the posterior probabilities. Therefore, we use a first-order Markov Chain Model to describe the dynamics of the traffic flow evolution process. We illustrate our approach for a small traffic network. Compared with the data from the microscopic traffic simulator SUMO, the proposed model can estimate the link traffic densities accurately and can give a reliable estimation of the uncertainties in the dynamic process of signalized traffic networks.","Bayesian; Markov traffic model; Traffic signals; Urban traffic network","en","journal article","","","","","","","","","","","Team Bart De Schutter","","",""
"uuid:641b229c-b904-4e3d-9d3f-8976c2787dcb","http://resolver.tudelft.nl/uuid:641b229c-b904-4e3d-9d3f-8976c2787dcb","Matrix-Pencil Approach-Based Interference Mitigation for FMCW Radar Systems","Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Ding, M. (TU Delft Electrical Engineering, Mathematics and Computer Science); Yarovoy, Alexander (TU Delft Microwave Sensing, Signals & Systems)","","2021","A novel matrix-pencil (MP)-based interference mitigation approach for frequency-modulated continuous-wave (FMCW) radars is proposed in this article. The interference-contaminated segment of the beat signal is first cut out, and then, the signal samples in the cutout region are reconstructed by modeling the beat signal as a sum of complex exponentials and using the MP method to estimate their parameters. The efficiency of the proposed approach for the interference with different parameters (i.e., interference duration, signal-to-noise ratio (SNR), and different target scenarios) is investigated by means of numerical simulations. The proposed interference mitigation approach is intensively verified on experimental data. Comparisons of the proposed approach with the zeroing and other beat-frequency interpolation techniques are presented. The results indicate the broad applicability and superiority of the proposed approach, especially in low SNR and long interference duration situations.","Chirp; Extrapolation; Frequency-modulated continuous-wave (FMCW) radar; Interference; interference mitigation; matrix pencil; Radar; Radar antennas; Radar signal processing; signal fusion.; Signal to noise ratio; signal fusion","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-03-01","Electrical Engineering, Mathematics and Computer Science","","Microwave Sensing, Signals & Systems","","",""
"uuid:cc190a2b-4932-4cac-af8b-f73324b2c4a1","http://resolver.tudelft.nl/uuid:cc190a2b-4932-4cac-af8b-f73324b2c4a1","Lagrangian sediment transport modelling as a tool for investigating coastal connectivity","Pearson, S.G. (TU Delft Environmental Fluid Mechanics; Deltares); Elias, E.P.L. (Deltares); van Ormondt, M (Deltares); Roelvink, F.E. (Deltares); Lambregts, P.M. (TU Delft Geo-engineering; Deltares); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics)","","2021","Estuaries and coasts can be conceptualized as connected networks of water and sediment fluxes. These dynamic geomorphic systems are governed by waves, tides, wind, and river input, and evolve according to complex nonlinear transport processes. To predict their evolution, we need to better understand the pathways that sediment takes from source through temporary storage areas to sink. Knowledge of these pathways is essential for predicting the response of such systems to climate change impacts or human interventions (e.g., dredging and nourishment). The conceptual framework of sediment connectivity has the potential to expand our system understanding and address practical coastal management problems (Pearson et al., 2020). Connectivity provides a structured framework for analyzing these sediment pathways, schematizing the system as a series of geomorphic cells or nodes, and the sediment fluxes between those nodes as links (Heckmann et al., 2015). Once organized in this fashion, the resulting network can be expressed algebraically as an adjacency matrix: sediment moving from a given source to different receptors. There is a wealth of pre-existing statistical tools and techniques that can be used to interpret the data once it is in this form, drawing on developments in other scientific disciplines (Newman, 2018; Rubinov & Sporns, 2010). Lagrangian flow networks have been increasingly used to analyze flow and transport pathways in oceanographic and geophysical applications (Padberg-Gehle & Schneide, 2017; Reijnders et al., 2021; Ser-Giacomi et al., 2015). However, this approach has not yet been adopted to analyze coastal or estuarine sediment transport, and requires a multitude of field measurements or numerical model simulations. Lagrangian particle tracking has been widely used to assess connectivity in the context of oceanography and marine ecology (Hufnagl et al., 2016; van Sebille et al., 2018), because the models record the complete history of a particle’s trajectory, not only its start and end points. Particle tracking models are also relatively fast and lend themselves well to parallel computing (Paris et al., 2013). This approach thus permits a faster and more detailed analysis of sediment connectivity than existing Eulerian approaches (e.g., Pearson et al., (2020)). Although several Lagrangian sediment transport models have been developed (e.g., (MacDonald & Davies, 2007; Soulsby et al., 2011)), they have not been used to support connectivity studies. Hence, there is a need for Lagrangian sediment particle tracking tools tailored to predicting sediment transport pathways and determining connectivity of complex coastal systems. To meet this need, we developed a Lagrangian sediment transport model, SedTRAILS (Sediment TRAnsport vIsualization & Lagrangian Simulator) and used it to develop a sediment connectivity network. Our approach provides new analytical techniques for distilling relevant patterns from the chaotic, spaghetti-like network of sediment pathways that often characterize estuarine and coastal systems. We demonstrate a proof of concept for our approach by applying it to a case using these tools.","Coastal sediment transport; Coastal nourishments and interventions","en","conference paper","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:e87c9837-7d25-409a-ae2c-66cc5395666f","http://resolver.tudelft.nl/uuid:e87c9837-7d25-409a-ae2c-66cc5395666f","A Matheuristic for the Integrated Disruption Management of Traffic, Passengers and Stations in Urban Railway Lines","Bešinović, Nikola (TU Delft Transport and Planning); Wang, Yihui (Beijing Jiaotong University); Zhu, Songwei (Beijing Jiaotong University); Quaglietta, E. (TU Delft Transport and Planning); Tang, Tao (Beijing Jiaotong University); Goverde, R.M.P. (TU Delft Transport and Planning)","","2021","In big cities, the metro lines usually face great pressure caused by huge passengers demand, especially during peak hours. When disruptions occur, passengers accumulate quickly at stations. It is of great importance for dispatchers to take passenger flow control into consideration for the traffic management to ensure passengers' safety and to maintain their satisfaction. This paper proposes an integrated disruption management model, which incorporates train rescheduling and passenger flow control. In this model, the train services can be short-turned, cancelled and rerouted, while the number of passengers entering a station is managed by controlling the station gates with consideration of the capacities of platforms and trains. Moreover, the number of passengers arriving at a station is calculated according to the origin-destination matrices. The objectives are to recover the train operation to the original timetable as soon as possible and to minimize the waiting time of passengers outside the stations. With the interaction between train services, passengers and station gates, an iterative metaheuristic approach is proposed to solve the integrated disruption management problem. Based on the data of a Beijing metro line, numerical experiments are conducted to test the proposed algorithm. The results demonstrate the importance of integrated disruption management and the effectiveness of our solution method.","Delays; disruption; Iterative methods; Logic gates; Mathematical model; passengers; Rail transportation; Rails; Railway; resilience; Safety; stations.; trains","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:bbdbc0a3-7bfd-42ee-87fd-4cb07b971b36","http://resolver.tudelft.nl/uuid:bbdbc0a3-7bfd-42ee-87fd-4cb07b971b36","Wheel-rail impact at an insulated rail joint in an embedded rail system","Yang, Z. (TU Delft Railway Engineering); Zhang, P. (TU Delft Railway Engineering); Wang, L. (TU Delft Railway Engineering)","","2021","With dynamic behaviour different from that of traditional discretely supported tracks, continuously supported embedded rail systems (ERSs) have been increasingly used in railway bridges, level crossings, trams, and high-speed lines. However, studies on ERSs have been limited, and none of them have addressed the wheel-rail impact-induced dynamic response, although wheel-rail impact is a main cause of ERS degradation. This paper studies, numerically and experimentally, the wheel-rail impact at an insulated rail joint (IRJ) used in the ERS. As a weak spot of the track, the IRJ results in discontinuities in the track support stiffness and wheel-rail contact geometry. This study first develops an explicit finite element model to simulate the vibration responses of the IRJ in the ERS when excited by a hammer and passing wheel loads. The simulated dynamic behaviours (represented by the hammer-excitation frequency response function) at a frequency up to 5 kHz and a wheel-rail impact vibration frequency up to 10 kHz are then validated with a field hammer test and a train pass-by measurement, respectively. Both the experimental study and numerical modelling reveals that the major frequencies of the impact vibration at the IRJ in the ERS depend mainly on geometric irregularities in the IRJ region and the train speed, rather than on the resonances of the track structure, as in the case of the discretely supported IRJ. This finding is meaningful to the engineering practice because it indicates a continuously supported IRJ in the ERS is more impact resistant, especially when the IRJ geometry is adequately maintained, e.g. by timely grinding.","Finite element modelling; Embedded rail systems; Wheel-rail impact; Insulated rail joint; Hammer test; Pass-by measurement","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:c501130a-9eca-427a-bc71-2410f15532cf","http://resolver.tudelft.nl/uuid:c501130a-9eca-427a-bc71-2410f15532cf","Impedance Modeling for Three-Phase Inverters with Double Synchronous Reference Frame Current Controller in the Presence of Imbalance","Beloqui Larumbe, L. (TU Delft DC systems, Energy conversion & Storage); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Wang, L. (TU Delft DC systems, Energy conversion & Storage); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2021","This article presents a small-signal model for power-electronics converters that use a typical control structure in wind energy applications: the double synchronous reference frame current control. The article considers the presence of unbalanced currents and voltages, and analyzes their impact on the frequency couplings of the converter. In addition, it is revealed that, in the presence of negative-sequence voltage synchronization, the converter presents an additional coupling at -2f_1-f_p.","Double synchronous reference frame; frequency coupling; impedance modeling; phase locked loop (PLL); small-signal modeling","en","journal article","","","","","","","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:1d2369ce-dca1-423e-a4c2-d2dfe166466b","http://resolver.tudelft.nl/uuid:1d2369ce-dca1-423e-a4c2-d2dfe166466b","Measuring geometric imperfections of variable–angle filament–wound cylinders with a simple digital image correlation setup","Castro, Saullo G.P. (TU Delft Aerospace Structures & Computational Mechanics); Almeida Jr., J.H.S. (Queen's University Belfast; Aalto University); St-Pierre, Luc (Aalto University); Wang, Z. (TU Delft Aerospace Structures & Computational Mechanics; University of Electronic Science and Technology of China)","","2021","Measuring the geometric imperfections in cylindrical shells is a critical step necessary to create accurate numerical models that can capture the imperfection-sensitive behavior of these structures. Modern composite structures, such as variable–angle filament–wound (VAFW) cylinders, have a unique imperfection signature that is still unknown to the scientific community. This new class of variable–stiffness structures developed by our research group combines wide tailoring capabilities with the efficient manufacturability enabled by filament winding process. The present study proposes a novel imperfection measurement method that is simple and applicable to both small and large structures. The topographic data is measured with only a pair of cameras. Practical aspects of using digital image correlation (DIC) are described and discussed in detail, such as lighting, focus adjustment, and calibration. State–of–the–art best–fit routines, based on least–squares optimization, are used to transform raw data into a common coordinate system. Finally, the transformed data is stitched to build a full 3D imperfection pattern that can be readily used in a nonlinear finite element analysis. The developed method is used to measure the imperfections of 12 VAFW cylinders. The mass of the cylinders is used to validate the geometric imperfections and evaluate the variability of the proposed methodology.","Cylindrical shells; Digital image correlation; Experimental characterization; Filament winding; Geometric imperfection; Variable-angle","en","journal article","","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:8d19317c-c4db-4a03-bf3a-10116298fb18","http://resolver.tudelft.nl/uuid:8d19317c-c4db-4a03-bf3a-10116298fb18","A Response Spectrum Analysis of Wind Deflection in Railway Overhead Contact Lines Using Pseudo-Excitation Method","Song, Yang (Norwegian University of Science and Technology (NTNU)); Zhang, Mingjie (Norwegian University of Science and Technology (NTNU)); Wang, H. (TU Delft Railway Engineering)","","2021","The wind deflection of overhead contact lines (OCLs) challenges the stable and safe operation of electrified railways. The steady wind causes the static deflection of the contact line, while the fluctuating wind leads to the OCL buffeting. This paper performs a response spectrum analysis of the wind deflection caused by the combined effects of steady and fluctuating winds. Considering the initial configuration of OCL, an absolute nodal coordinate formulation method is employed to model the OCL. A spatial wind field including the fluctuating wind in three directions is constructed and the aerodynamic forces on the OCL are derived. A nonlinear solution procedure is proposed to include the geometrical nonlinearity and dropper slackness in the evaluation of static wind deflection. The pseudo-excitation method is utilised to evaluate the buffeting response of the OCL with stochastic wind load. The analysis results indicate that the dropper slackness has a significant effect on the vertical static deflection. Under an extreme wind speed of 40 m/s, the contact line is always within the safe working range of pantograph head when only the steady wind load is considered. However, the stochastic wind load causes non-negligible fluctuation of OCL, and the contact line may be outside of the pantograph working range under the same wind speed. Sensitivity analyses on the effects of some key parameters to the OCL buffeting suggest that the increases of damping ratio and the tension class are effective measures to improve the wind-resistance capability of OCL.","Electrified Railway; Overhead Contact Line; Pantograph Working Length; Force; Wind Deflection; Pseudo-Excitation Method; Buffeting","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-08-31","","","Railway Engineering","","",""
"uuid:868f29fd-9095-4201-aa4f-4c1d494306c5","http://resolver.tudelft.nl/uuid:868f29fd-9095-4201-aa4f-4c1d494306c5","Dynamic morphology of the Sittaung estuary, Myanmar: A detailed investigation and modeling of rapid bank erosion","de Haas, H. (Student TU Delft); Wang, Zhengbing (TU Delft Coastal Engineering); Mosselman, E. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Bogaard, T.A. (TU Delft Water Resources); Cleveringa, J. (ARCADIS Nederland)","","2021","","Bank erosion; Sittaung estuary; Numerical modelling","en","poster","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-08-12","","","Coastal Engineering","","",""
"uuid:6a253a71-3c07-48cb-bb93-cdb12afa7886","http://resolver.tudelft.nl/uuid:6a253a71-3c07-48cb-bb93-cdb12afa7886","Micromechanics-based complex modulus prediction of crumb rubber modified bitumen considering interparticle interactions","Wang, H. (TU Delft Pavement Engineering; The Hong Kong Polytechnic University); Zhang, H. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Khalifa University); Leng, Zhen (The Hong Kong Polytechnic University)","","2021","Crumb rubber modified bitumen (CRMB) can be regarded as a binary composite system in which swollen rubber particles are embedded in the bitumen matrix. The current study aims to further improve the prediction accuracy of micromechanical models for CRMB by considering the interparticle interactions. To accomplish this goal, two different strategies were used. Firstly, the (n+1)-phase model was applied to the CRMB system by considering the multilayer properties of swollen rubber particles. Secondly, a new micromechanical scheme called the J-C model was used to account for the interparticle interaction issue. Results show that the (n+1)-phase models slightly increase the prediction accuracy but the underestimation of complex modulus at lower frequencies remains unsolved. The J-C model remedies the underestimation of modulus in the low-frequency range by other models and provides an overall improvement for the relative prediction accuracy by properly addressing the interparticle interactions from the perspective of particle configuration.","complex shear modulus; Crumb rubber modified bitumen; interparticle interaction; micromechanics; radial distribution function","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:dc8d11e3-3097-4396-a8de-a4abe41c6e33","http://resolver.tudelft.nl/uuid:dc8d11e3-3097-4396-a8de-a4abe41c6e33","Improving Annual Energy Production of Doubly-Fed Induction Generators","Wang, X. (TU Delft Transport Engineering and Logistics); Liu, Dong (Hohai University); Polinder, H. (TU Delft Transport Engineering and Logistics)","","2021","Doubly fed induction generator (DFIG) based wind turbines are most employed for onshore applications because of their cost-effectiveness. The drivetrain improvement is barely studied due to the maturity of the DFIG based systems. This paper investigates two methods for improving the annual energy production (AEP) of the DFIG based wind turbines. They are referred to as short-circuited and -Y-connected DFIGs. The origins of the AEP improvement are elaborated from the drivetrain perspective. The improvement is quantified by the aerodynamic model of the turbine and the steady-state model of the DFIG. The two methods are then compared when applied to six regions with different wind speed distributions. The AEP improvements at six regions are evaluated and compared to derive the feasibility of the methods for different locations.","aerodynamic model; annual energy production (AEP); Delta-Y connection; Doubly-fed induction generator (DFIG); short-circuited connection","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-car Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-09-03","","","Transport Engineering and Logistics","","",""
"uuid:ccd741ed-c338-44a0-bff3-17208de8cc2e","http://resolver.tudelft.nl/uuid:ccd741ed-c338-44a0-bff3-17208de8cc2e","Short-circuit characteristics of superconducting permanent magnet generators for 10 MW wind turbines","Liu, Dong (Hohai University); Song, Xiaowei (Vestas Wind System A/S); Wang, X. (TU Delft Transport Engineering and Logistics); Elhindi, Mohamed (Hohai University); Hasanov, Urfan (Hohai University); Gou, Xiaofan (Hohai University); Ye, Changqing (Hohai University)","","2021","Superconducting permanent magnet generators (SCPMGs) are a potential candidate for 10 MW direct-drive wind turbine applications. This paper presents two 10 MW SCPMG designs using MgB<sub>2</sub> cables for the armature winding and investigates the short-circuit characteristics of the designed SCPMGs. The first part of the results shows that the SCPMGs can double the shear stress of a conventional low-speed permanent magnet (PM) generator (from 65 kPa to 130 kPa) whilst avoiding demagnetization of the PMs in rated-load operation. However, the power factor has to drop to a range of 0.7-0.8. The second part of the results shows that during a sudden three-phase short circuit, the superconducting armature winding is prone to quench and the PMs are likely to be demagnetized in both proposed designs.","Demagnetization; MgB2; permanent magnet; short circuit; superconducting generator; wind turbine","en","journal article","","","","","","Accepted Author Manuscript","","","","","Transport Engineering and Logistics","","",""
"uuid:6a5eb501-dc8b-4334-81bf-447fd1ac83f6","http://resolver.tudelft.nl/uuid:6a5eb501-dc8b-4334-81bf-447fd1ac83f6","Sediment Characteristics and Intertidal Beach Slopes along the Jiangsu Coast, China","Kuai, Y. (TU Delft Coastal Engineering); Tao, Jianfeng (Hohai University); Zhou, Z. (TU Delft Coastal Engineering; East China Normal University); Aarninkhof, S.G.J. (TU Delft Hydraulic Engineering); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2021","Tidal flats play an important role in promoting coastal biodiversity, defense against flooding, land reclamation and recreation. Many coastal tidal flats, especially the tide-dominant ones, are muddy. However, the number of studies on the profile shape and surficial sediment distribution of muddy tidal flats is small compared to sandy beaches. Based on high spatial-resolution measurements along the tide-dominant Jiangsu Coast, China, we analyzed the morphology and sediment characteristics of the unvegetated intertidal flats along the Jiangsu Coast. The Jiangsu Coast can be divided into an eroding northern part (north coast) and an accreting southern part (south coast). The beach slope of the north coast shows a southward flattening trend, apart from some outliers related to rocky parts of the coastline. We found alternating very fine and coarse sediment (depending on the local clay content) for different locations along the north coast, which can be explained from consolidation and armoring-induced erosion resistance. In the south coast, we found gradual coarsening of bed surface sediment and gradual flattening of beach slopes to the south. This seemingly unexpected pattern is explained by the flood-dominant current causing landward sediment transport, larger tidal range in the south part, sheltering effect of the Radial Sand Ridges, and contribution of different sediment sources, viz. the Abandoned Yellow River Delta and the Radial Sand Ridges. In the cross-shore direction, the sediment grain size decreases landward. Waves are only of secondary importance for the sediment dynamics at the unvegetated tidal flats along the Jiangsu Coast.","Beach slope; Human intervention; Intertidal beach; Jiangsu Coast; Surficial sediment grain-size","en","journal article","","","","","","","","","","Hydraulic Engineering","Coastal Engineering","","",""
"uuid:ad181111-30bb-4235-9735-e50d427da003","http://resolver.tudelft.nl/uuid:ad181111-30bb-4235-9735-e50d427da003","Clutter-Contaminated Signal Recovery in Spectral Domain for Polarimetric Weather Radar","Yin, Jiapeng (National University of Defense Technology); Schleiss, M.A. (TU Delft Atmospheric Remote Sensing); Wang, Xuesong (National University of Defense Technology)","","2021","The use of spectral polarimetric filters in the range-Doppler domain shows great promise for clutter mitigation in weather radar applications. One limitation of these filters is that they cannot deal with situations in which ground clutter and precipitation overlap. In this letter, we propose a new signal recovery technique based on kriging in the spectral domain to recover the precipitation in clutter-contaminated areas. Using synthetic radar data, we test our new method and compare its performance to that of Gaussian model adaptive processing and bilinear interpolation. Our results indicate that kriging is the most accurate and robust technique out of the three.","Clutter-contaminated; ground clutter (GC); kriging; signal recovery; spectral-polarimetry; weather radar","en","journal article","","","","","","","","","","","Atmospheric Remote Sensing","","",""
"uuid:44794587-66f0-4f0a-876f-cb3716468b0a","http://resolver.tudelft.nl/uuid:44794587-66f0-4f0a-876f-cb3716468b0a","Modelling of light scattering by gold nanoparticles at optical fibre interfaces","Wang, X. (TU Delft Structural Integrity & Composites); Benedictus, R. (TU Delft Structural Integrity & Composites); Groves, R.M. (TU Delft Structural Integrity & Composites)","","2021","Optical fibre backscatter reflectometry is an important technique for Structural Health Monitoring (SHM). In recent years, increasing the intensity of backscattered light in backscatter reflectometry has shown the advantage of improving the signal detection in shape sensing and temperature detection due to the increase of signal to noise ratio and this approach could potentially be used to improve the performance of an SHM system. Doping nanoparticles (NPs) is a method to increase the intensity of backscattered light in distributed fibre optic sensing. The increased intensity of light backscattered by the NPs needs to be investigated to design suitable optical sensing fibres with NPs for backscatter reflectometry. In this work NPs were added to refractive index matching liquid and tested with commercial NP suspensions experimentally between the tips of two optical fibres. An estimate of the intensity of backscattered light from the NPs in this structure was performed by simulation to give a better understanding of the expected levels of intensities of scattered light from NPs in this distributed fibre optic sensing configuration. We present analytical models based on Mie theory and the Monte Carlo Method. Simulated results are presented, for a broad bandwidth Gaussian spectra shape incident light with a central wavelength around 1550 nm, to match the experimental conditions in this work. The novelty is in developing this model for scattered light by NPs at optical fibre interfaces and the evaluation of the possibility of detection by the calculated scattered intensity levels.","backscattering; gold nanoparticle suspension; light scattering model; optical fibre","en","journal article","","","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:5ab708a8-d735-4b1a-89e8-c6c3e0e30cec","http://resolver.tudelft.nl/uuid:5ab708a8-d735-4b1a-89e8-c6c3e0e30cec","Experimental comparisons between one-part and normal (two-part) alkali-activated slag binders","Ren, Jie (Shenzhen University); Sun, Hongfang (Shenzhen University); Li, Qun (Shenzhen University); Li, Z. (TU Delft Materials and Environment); Ling, Li (Shenzhen University); Zhang, Xiaogang (Shenzhen University); Wang, Yanshuai (Shenzhen University); Xing, Feng (Shenzhen University)","","2021","One-part alkali-activated slag (AAS) binders are more promising in large-scale constructions because one-part mixing procedure is safer and easier to handle compared to normal two-part method. Thus, this study aims at investigating different properties of one-part AAS binders and control samples prepared using the two-part method. Experimental results of the former suggested the hardening time was greatly extended, but the workability showed little difference. Besides, compared to the control, one-part AAS binders had similar early compressive strength (within 7 days) and flexural strength in all tested curing stages but lower later compressive strength (from 28 days). The characterisation of the porous structures suggests that there were fewer C-A-S-H gels for one-part binders evidenced by less volume of mesopores but with larger amount of bigger pores. In addition, mineralogical and microstructural analyses imply that there was no hydrotalcite formed in the one-part AAS binders. Moreover, one-part AAS binders are more susceptible to efflorescence, presumably further affecting their surface and long-term durability.","One-part alkali-activated slag; Mechanical properties; Mineralogical and microstructural analysis; Pore microstructure; Efflorescence","en","journal article","","","","","","Accepted author manuscript","","2023-10-09","","","Materials and Environment","","",""
"uuid:120f593c-1522-439f-8e15-8fab9d429ffd","http://resolver.tudelft.nl/uuid:120f593c-1522-439f-8e15-8fab9d429ffd","Removal of Hydrogen Peroxide Residuals and By-Product Bromate from Advanced Oxidation Processes by Granular Activated Carbon","Wang, F. (TU Delft Sanitary Engineering; Shanghai University); Zhang, Lu (Shanghai University); Wei, L. (TU Delft Sanitary Engineering); van der Hoek, J.P. (TU Delft Sanitary Engineering; Waternet)","","2021","During drinking water treatment, advanced oxidation process (AOP) with O3 and H2O2 may result in by-products, residual H2O2 and BrO3−. The water containing H2O2 and BrO3− often flows into subsequent granular activated carbon (GAC) filters. A concentrated H2O2 solution can be used as GAC modification reagent at 60 °C to improve its adsorption ability. However, whether low concentrations of H2O2 residuals from AOP can modify GAC, and the impact of H2O2 residuals on BrO3− removal by the subsequent GAC filter at ambient temperature, is unknown. This study evaluated the modification of GAC surface functional groups by residual H2O2 and its effect on BrO3− removal by GAC. Results showed that both H2O2 and BrO3− were effectively removed by virgin GAC, while pre-loaded and regenerated GACs removed H2O2 but not BrO3− anymore. At the ambient temperature 150 µmol/L H2O2 residuals consumed large amounts of functional groups, which resulted in the decrease of BrO3− removal by virgin GAC in the presence of H2O2 residuals. Redox reactions between BrO3− and surface functional groups played a dominant role in BrO3− removal by GAC, and only a small amount of BrO3− was removed by GAC adsorption. The higher the pH, the less BrO3− removal and the more H2O2 removal was observed.","Bromate; Granular activated carbon; Hydrogen peroxide; Ozone; Surface functional groups","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:8890952b-8e99-4e2b-b55b-3d1c1262874a","http://resolver.tudelft.nl/uuid:8890952b-8e99-4e2b-b55b-3d1c1262874a","Reactive Transport Modelling of Chloride Ingress in Saturated Coral Aggregate Concrete","Guo, Bingbing (Xi'an University of Architecture and Technology); Li, Z. (TU Delft Materials and Environment); Fu, Qiang (Xi'an University of Architecture and Technology); Wang, Yan (Xi'an University of Architecture and Technology); Huang, Daguan (Xi'an University of Architecture and Technology); Niu, Ditao (Xi'an University of Architecture and Technology)","","2021","Utilizing coral aggregate concrete (CAC) for construction on remote islands can significantly reduce construction cost and period, CO2 emission, and consumption of non-renewable energy. The durability of reinforced CAC structures is critically influenced by their resistance to chloride attack. In this study, a reactive transport modelling was developed to investigate chloride ingress in CAC, in which a COMSOL-PHREEQC interface based on MATLAB language was established. The experiment from the literature was taken as a benchmark example. The results show that the developed numerical model can accurately predict chloride transport in CAC. Differing from ordinary aggregate concrete (OAC), Kuzel’s salt does not appear in cement hydrate compounds of CAC during chloride ingress. The numerical results indicate that the penetration depth of chloride in CAC gradually increases as the exposure time is prolonged. When CAC is exposed to an external chloride solution, the decrease in the pH of the pore solution affects the precipitation of Friedel’s salt, which is detrimental to the chemical binding of chloride.","coral aggregates concrete; chloride ingress; reactive transport modelling; chloride binding; corrosion","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:a085f70c-92a5-49cc-956e-a945a2c7f6c4","http://resolver.tudelft.nl/uuid:a085f70c-92a5-49cc-956e-a945a2c7f6c4","Investigating the High- And Low-Temperature Performance of Warm Crumb Rubber-Modified Bituminous Binders Using Rheological Tests","Wang, H. (TU Delft Pavement Engineering; The Hong Kong Polytechnic University); Liu, X. (TU Delft Pavement Engineering); Apostolidis, P. (TU Delft Pavement Engineering); Wang, Di (Technical University of Braunschweig); Leng, Zhen (The Hong Kong Polytechnic University); Lu, Guoyang (The Hong Kong Polytechnic University); Erkens, S. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Khalifa University of Science and Technology)","","2021","Rubberized asphaltic materials have been frequently combined with warm-mix asphalt technologies to tackle the issues of high energy consumptions and emissions during construction. Effective and accurate characterization of binder properties is conducive to the improvement of long-term pavement performance. The current study aims to quantify the effects of rubber content and warm-mix additives on rutting and thermal cracking performance of crumb rubber-modified bitumen (CRMB), and explore the rubber and additives modification mechanisms and their impacts on the binder performance. CRMBs containing different rubber contents and warm-mix additives after long-term aging were subject to multiple stress creep and recovery (MSCR) tests and low-temperature frequency sweep tests using a dynamic shear rheometer (DSR) with 4-mm loading plate to investigate the high- and low-temperature performance, respectively. Rheological tests were also conducted on the bitumen and rubber phases of CRMB to understand the rubber modification mechanism. Results show that CRMB binders have superior rutting and thermal cracking resistance due to rubber modification. The improvement of high- or low-temperature performance is more prominent at higher rubber concentrations. The effects of warm-mix additives on the rutting and thermal cracking performance are different. Generally, the wax-based additive improves the rutting resistance but negatively affects the low-temperature performance. In contrast, the chemical-based additive has an opposite effect except for the high-temperature performance of neat bitumen. The stiffening of the bitumen phase and the contribution of swollen rubber particles in the bitumen matrix together contribute to the peculiar viscoelastic response of CRMB, i.e., stiffer/softer and more elastic at high/low temperatures. This modification mechanism explains the superior rutting and thermal cracking performance of CRMB.","Bitumen; Crumb rubber; Rheology; Rutting; Thermal cracking; Warm-mix additives","en","journal article","","","","","","Accepted Author Manuscript","","","","","Pavement Engineering","","",""
"uuid:e488748a-0547-47bd-9212-b85799f3374b","http://resolver.tudelft.nl/uuid:e488748a-0547-47bd-9212-b85799f3374b","Python Supervised Co-simulation for A Day-long Harmonic Evaluation of EV Charging","Wang, L. (TU Delft DC systems, Energy conversion & Storage); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Beloqui Larumbe, L. (TU Delft DC systems, Energy conversion & Storage); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2021","To accurately simulate electric vehicle DC fast chargers' (DCFCs') harmonic emission, a small time step, i.e., typically smaller than 10 μs, is required owing to switching dynamics. However, in practice, harmonics should be continuously assessed with a long duration, e.g., a day. A trade-off between accuracy and time efficiency thus exists. To address this issue, a multi-time scale modeling framework of fast-charging stations (FCSs) is proposed. In the presented framework, the DCFCs' input impedance and harmonic current emission in the ideal grid condition, that is, zero grid impedance and no background harmonic voltage, are obtained based on a converter switching model with a small timescale simulation. Since a DCFC's input impedance and harmonic current source are functions of the DCFC's load, the input impedance and harmonic emission at different loads are obtained. Thereafter, they are used in the fast-charging charging station modeling, where the DCFCs are simplified as Norton equivalent circuits. In the station level simulation, a large time step, i.e., one minute, is used because the DCFCs' operating power can be assumed as a constant over a minute. With this co-simulation, the FCSs' long-term power quality performance can be assessed time-efficiently, without losing much accuracy.","Power quality; charging infrastructure for electric vehicles (EVs); harmonic modeling","en","journal article","","","","","","","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:efcf4727-5f29-450d-9971-32d4cd9ba16c","http://resolver.tudelft.nl/uuid:efcf4727-5f29-450d-9971-32d4cd9ba16c","Multi-timescale Modeling of Fast Charging Stations for Power Quality Analysis","Wang, L. (TU Delft DC systems, Energy conversion & Storage); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Beloqui Larumbe, L. (TU Delft DC systems, Energy conversion & Storage); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2021","To accurately simulate the harmonic emission of EV DC fast chargers (DCFCs) and the harmonic voltage of the power grid to which the chargers are connected, a small time-step, i.e., typically smaller than 10μs, is required. However, for harmonic assessment, a long timescale, typically a day, is required. A conflict between accuracy and time efficiency exists. To address this issue, a multitimescale modeling framework of fast charging stations (FCSs) is proposed in this paper. In the presented framework, the DCFCs’ input impedance and harmonic current emission in the ideal grid condition, i.e., the grid impedance is zero and there are no background harmonic voltages, is obtained firstly through a converter switch model with a small timescale. Since the DCFC’s input impedance and harmonic current source change in the charging course, the input impedance and harmonic emission at different input power should be obtained. Then, the DCFCs’ input impedance and harmonic emission will be used in the fast-charging station modeling, where the DCFCs are simplified as their Norton equivalent circuits. In the station level modeling, a bigger time step, i.e., 1 minute, is used, since the DCFCs’ operating power can be assumed as a constant in one minute. With this framework, the FCSs’ long-term power quality performance can be assessed efficiently without neglecting the DCFCs’ small timescale dynamics.","Charging Infrastructure for EV's; Power quality; Modeling; Harmonics","en","conference paper","IEEE","","","","","Accepted Author Manuscript","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:3145517c-b402-4adc-89c5-2c1e22c734c9","http://resolver.tudelft.nl/uuid:3145517c-b402-4adc-89c5-2c1e22c734c9","Mapping key features and dimensions of the inclusive city: A systematic bibliometric analysis and literature study","Liang, Danni (Dalian University of Technology); de Jong, Martin (Rotterdam School of Management; Fudan University; Erasmus Universiteit Rotterdam); Schraven, D.F.J. (TU Delft Integral Design & Management); Wang, Lili (Dalian University of Technology)","","2021","Many local governments engaging in sustainable urban development also have a growing interest in becoming inclusive too, brand themselves as such and develop policies to become inclusive cities. However, knowing what exactly this entails and how it can be achieved is not always quite straightforward and requires thorough theoretical and empirical exploration. Consequently, we present a systematic deconstruction of the inclusive city concept in order to develop a better understanding of the main features and dimensions; this is done by means of both a bibliometric analysis and qualitative literature review. The results indicate that inclusiveness is multidimensional and comprised of spatial, social, environmental, economic, and political dimensions in which the characteristics of participation, equity, accessibility and sustainability are sometimes interwoven. Overall, the inclusive city is not merely a precondition for the creation of just space, well-being, and environmental responsibility, but also an opportunity to take stock of interests of stakeholders in cities and to create local public value. The findings have implications for urban policy and practice, more specifically, the clarification of the inclusive city concept and conceptual dimensions will provide significant reference for policymakers and practitioners to make prudent decisions in the process of creating an inclusive city.","Inclusive city; bibliometric analysis; equity; literature review; sustainable urbanization","en","journal article","","","","","","","","","","","Integral Design & Management","","",""
"uuid:b19bbc23-3205-42b3-8080-a448973cdef2","http://resolver.tudelft.nl/uuid:b19bbc23-3205-42b3-8080-a448973cdef2","Modeling the hydraulic excavation of cohesive soil by a moving vertical jet","Wang, Boyao (Student TU Delft); van Rhee, C. (TU Delft Offshore and Dredging Engineering; TU Delft Rivers, Ports, Waterways and Dredging Engineering); Nobel, Arno (Royal Boskalis Westminster); Keetels, G.H. (TU Delft Offshore and Dredging Engineering)","","2021","In dredging, high pressure water jets are commonly applied to assist the mobilization of soil. This work considers the excavation of cohesive soil. The key objective is to predict the development of the cavity in the soil as a function of the undrained shear strength, translation velocity and hydrodynamic pressure of a single nozzle. A generic computational fluid dynamics (CFD) model has been developed that captures both the jet flow and the soil failure in a single framework. The results are compared with data from a previous experimental study. The CFD model predicts the cavity dimensions with reasonable accuracy. In addition the model provides detailed data to study the cyclic nature of the soil failure process. The CFD model is promising and can be applied for more complex nozzle configurations to assist the design process of dragheads and improve production estimates.","Cohesive soil; Computational fluid dynamics (CFD); Dredging; Drift-flux model; Dynamic mesh; Moving jet; OpenFOAM; Undrained soil failure","en","journal article","","","","","","","","","","","Offshore and Dredging Engineering","","",""
"uuid:7f13239d-6a7d-4547-ab36-798f92be9e72","http://resolver.tudelft.nl/uuid:7f13239d-6a7d-4547-ab36-798f92be9e72","Grid Impact of Electric Vehicle Fast Charging Stations: Trends, Standards, Issues and Mitigation Measures - An Overview","Wang, L. (TU Delft DC systems, Energy conversion & Storage); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Slangen, T (ElaadNL); Bauer, P. (TU Delft DC systems, Energy conversion & Storage); van Wijk, T (ElaadNL)","","2021","With growing concern on climate change, widespread adoption of electric vehicles (EVs) is important. One of the main barriers to EV acceptance is range anxiety, which can be alleviated by fast charging (FC). The main technology constraints for enabling FC consist of high-charging-rate batteries, high-power-charging infrastructure, and grid impacts. Although these technical aspects have been studied in literature individually, there is no comprehensive review on FC involving all the perspectives. Moreover, the power quality (PQ) problems of fast charging stations (FCSs) and the mitigation of these problems are not clearly summarized in the literature. In this paper, the state-of-the-art technology, standards for FC (CHAdeMO, GB/T, CCS, and Tesla), power quality issues, IEEE and IEC PQ standards, and mitigation measures of FCSs are systematically reviewed.","Charging stations; electric vehicles; power quality; power system stability","en","journal article","","","","","","","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:f87555ba-18e6-4c2b-83bc-a3531a540f67","http://resolver.tudelft.nl/uuid:f87555ba-18e6-4c2b-83bc-a3531a540f67","Removal of organic micropollutants by well-tailored granular zeolites and subsequent ozone-based regeneration","Fu, Mingyan (TU Delft Sanitary Engineering); Wang, Jiawei (Student TU Delft); Heijman, Sebastiaan (TU Delft Sanitary Engineering); van der Hoek, J.P. (TU Delft Sanitary Engineering; Waternet)","","2021","Advanced technologies to remove organic micropollutants (OMPs) from municipal wastewater have gained much attention over the last decades. Adsorption by zeolites is one of these technologies. In this study, the regeneration performance of well-tailored granular zeolites loaded with OMPs was evaluated. The selected OMPs were categorized into three groups due to the adsorption performance: high, medium and low adsorbance. Gaseous ozone was directly applied to regenerate dried zeolite granules at an ozone concentration of 30 mg/L and a gas flow rate of 0.2 L/min (0.04 m/s). For the high and medium adsorbing OMPs, 45 min of ozonation was long enough to fully restore their adsorption capacity. For the low adsorbing OMPs, the regeneration efficiency reached 60% after 60 min of ozonation. Interestingly, their recovered adsorption capacities firstly decreased and subsequently increased along with the ozonation duration. The dramatically decrease was most probably due to the presence of the transformation products generated from the ozonation of some selected OMPs. In seven sequential adsorption-regeneration cycles, the adsorption capacity for 75% of the selected OMPs was fully recovered at an ozonation duration of 60 min in each regeneration. The assumed accumulation of the ozonation transformation products only influenced the adsorption of low adsorbing OMPs in 7 cycles.","Adsorption; Granular zeolites; Organic micropollutants; Ozone-based regeneration; Transformation products","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:f4a57b84-255e-443b-9994-f37c7c179d4f","http://resolver.tudelft.nl/uuid:f4a57b84-255e-443b-9994-f37c7c179d4f","It Is Me, Chatbot: Working to Address the COVID-19 Outbreak-Related Mental Health Issues in China. User Experience, Satisfaction, and Influencing Factors","Zhu, Yonghan (Chongqing University); Janssen, M.F.W.H.A. (TU Delft Information and Communication Technology); Wang, Rui (Chongqing University); Liu, Yang (Chongqing University)","","2021","The global spread of COVID-19 has caused a huge number of confirmed cases and deaths, which in return leads to a plethora of mental disorders across the world. In order to address citizens’ psychological problems, government agencies in many countries have employed AI-based chatbots to provide mental health services. However, there is a limited understanding of the determinants affecting citizens’ user experience and user satisfaction when mental health services supported by chatbots are provided. Thus, based on the Theory of Consumption Values (TCV), this study proposes an analytical framework to investigate the factors that are important to citizens’ user experience and user satisfaction when they interact with mental health chatbots. Analysis of data collected from 295 chatbot users in Wuhan and Chongqing reveals that personalization, enjoyment, learning, and condition are positively related to user experience and user satisfaction. However, voice interaction fails to devote to citizens’ user experience and user satisfaction. Thus, government agencies and their AI service contractors should enhance the functions and systems of mental health chatbots to ensure citizens’ user experience and user satisfaction. Also, they should more positively promote the use of mental health chatbots during the public health emergency.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-05-01","","","Information and Communication Technology","","",""
"uuid:4c017a9f-22c8-49e7-8cdb-e737eb402b7e","http://resolver.tudelft.nl/uuid:4c017a9f-22c8-49e7-8cdb-e737eb402b7e","Deep Recursive Embedding for High-Dimensional Data","Zhou, Zixia (Fudan University); Zu, Xinrui (University of Twente); Wang, Yuanyuan (Fudan University); Lelieveldt, Boudewijn P.F. (Universiteit Leiden); Tao, Q. (TU Delft ImPhys/Medical Imaging)","","2021","Embedding high-dimensional data onto a low-dimensional manifold is of both theoretical and practical value. In this article, we propose to combine deep neural networks (DNN) with mathematics-guided embedding rules for high-dimensional data embedding. We introduce a generic deep embedding network (DEN) framework, which is able to learn a parametric mapping from high-dimensional space to low-dimensional space, guided by well-established objectives such as Kullback-Leibler (KL) divergence minimization. We further propose a recursive strategy, called deep recursive embedding (DRE), to make use of the latent data representations for boosted embedding performance. We exemplify the flexibility of DRE by different architectures and loss functions, and benchmarked our method against the two most popular embedding methods, namely, t-distributed stochastic neighbor embedding (t-SNE) and uniform manifold approximation and projection (UMAP). The proposed DRE method can map out-of-sample data and scale to extremely large datasets. Experiments on a range of public datasets demonstrated improved embedding performance in terms of local and global structure preservation, compared with other state-of-The-Art embedding methods. Code is available at https://github.com/tao-Aimi/DeepRecursiveEmbedding.","Data visualization; deep embedding network; deep recursive embedding; Feature extraction; Manifolds; Standards; t-distributed stochastic neighbor embedding; Tools; Training; uniform manifold approximation and projection; Unsupervised learning; unsupervised learning","en","journal article","","","","","","","","","","","ImPhys/Medical Imaging","","",""
"uuid:a46ffe78-6595-411a-98ee-397a4a95a09b","http://resolver.tudelft.nl/uuid:a46ffe78-6595-411a-98ee-397a4a95a09b","Incremental fault-tolerant control for a hybrid quad-plane UAV subjected to a complete rotor loss","Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics); Sun, Sihao (Student TU Delft)","","2021","Quad-plane is a popular type of electric vertical and takeoff/landing (eVTOL) vehicle that hybridizes a quadrotor and a fixed-wing airplane. However, the mechanical simplicity of a quad-plane also makes it vulnerable to rotor failures. When a complete rotor fails, it becomes physically impossible to stop the quad-plane from fast yaw spinning, which further induces considerable abnormal aerodynamic forces and moments on the wing. In this paper, a novel incremental adaptive sliding mode control (I-ASMC) is proposed to address these challenges. First, by exploiting sensor measurements, it simultaneously reduces the control model dependency and the minimum possible sliding mode control/observer gains. Second, finite-time convergence is guaranteed in the Lyapunov sense. Third, the control gains are automatically adapted to their minimum possible values without prior-knowledge on the uncertainty bounds. The proposed I-ASMC method is verified on a high fidelity simulation platform with computational fluid dynamic (CFD) aerodynamic models. Simulation results demonstrate that I-ASMC can drive a quad-plane with a complete loss of a single rotor to follow a trajectory. Its robustness to aerodynamic model uncertainties and rotor faults is also better than the linear quadratic regulator (LQR) and the incremental nonlinear dynamic inversion (INDI) control. In conclusion, the reduced model dependency, implementation simplicity, and improved robustness make the proposed I-ASMC promising for enhancing quad-plane safety in real life.","Adaptive sliding mode control; Aerodynamic modeling; Fault-tolerant control; Incremental nonlinear control; Quad-plane","en","journal article","","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:4a4c833a-48aa-4554-b3ec-a06b47566097","http://resolver.tudelft.nl/uuid:4a4c833a-48aa-4554-b3ec-a06b47566097","Morphodynamic modeling the impact of large-scale embankment on the large bar in a convergent estuary","Xie, Dongfeng (Zhejiang Institute of Hydraulics and Estuary); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); van der Wegen, Mick (IHE Delft Institute for Water Education; Deltares); Huang, Junbao (Zhejiang Institute of Hydraulics and Estuary)","","2021","Many alluvial estuaries worldwide include an inside bar system, a large sediment deposit deeply stretched into the estuary. A good example of such a system is the large sediment deposit in the Qiantang Estuary, China. Its length and height reach 130 km and 10 m, respectively. Bathymetrical comparison reveals that the large bar has moved seaward by around 15 km over the last decades, probably related to the large-scale coastal embankment project. This motivated a quantitative investigation of the impact of estuarine planform on the inside bar development. The bar morphology is reproduced by means of an idealized 1-D morphodynamic model. Model results suggest that the bar movement is related to a decreasing tidal prism, increasing flood dominance in the lower reach and enhanced ebb currents in the upper reach, in response to the embankment. The timescale of the morphological response is only several years. The rapid response is related to the strong tidal currents and large sediment fluxes within the estuary. Sensitivity experiments show that the location and dimensions of the bar are related to the convergence length of the estuary. A decrease of the convergence length causes seaward movement and shortening and lowering of the bar. The bar dimensions also depend on the ratio between river and tidal discharges. When the ratio increases, the bar apex moves seaward and the elevation decreases. The bar movement has significantly influenced the tidal bore in the Qiantang Estuary.","Morphodynamic modeling; Inside bar dimensions; Coastal embankment; Tidal bore; Qiantang Estuary; Coastal management","en","journal article","","","","","","Accepted Author Manuscript","","2023-09-24","","","Coastal Engineering","","",""
"uuid:4454ffd9-f43a-430f-838e-5e0597b940ca","http://resolver.tudelft.nl/uuid:4454ffd9-f43a-430f-838e-5e0597b940ca","The continuous swelling-degradation behaviors and chemo-rheological properties of waste crumb rubber modified bitumen considering the effect of rubber size","Ren, S. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Lin, P. (TU Delft Pavement Engineering); Wang, H. (TU Delft Pavement Engineering); Fan, W. (China University of Petroleum (East China)); Erkens, S. (TU Delft Pavement Engineering)","","2021","The chemo-rheological properties of crumb rubber modified bitumen are always unstable due to the mutable and uncontrollable swelling-degradation degree of crumb rubber in bitumen matrix. The study aimed at exploring the continuous swelling and degradation behaviors of crumb rubber modified bitumen (CRMB) considering the influence of rubber size through monitoring the dynamic viscosity changes of CRMB binders. Moreover, the synergistic effects of swelling-degradation degree and rubber size on the chemical and rheological properties of CRMB were investigated. The results revealed that the rubber size significantly influenced the swelling and degradation behaviors of CRMB. The reduction of rubber size shortened the equilibrium swelling and degra-dation time, while increased the related viscosity dramatically. Moreover, during the degradation process, the decrease of rubber size could accelerate the continuous swelling rate, increase the maximum viscosity and reduce the continuous swelling time of CRMB. Meanwhile, the high swelling degree and large rubber size were bene-ficial to enhance the high temperature properties, while the CRMB binder with high degradation degree showed the better low-temperature property, workability and wider Newtonian flow region. Furthermore, the degra-dation degree promoted the formation of free hydroxide groups, aldehydes, carboxylic acids and esters, while the swelling process increased the average molecular weight of whole liquid phase in CRMB binder. The outputs from this fundamental study are beneficial to provide the guidance to preparation conditions optimization of CRMB binders with different viscous property standards","Crumb rubber modified bitumen; Swelling; Degradation; Rubber size; Rheology; Chemical characterization","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:76a618d2-2b68-4195-adf5-f6d289dfb35d","http://resolver.tudelft.nl/uuid:76a618d2-2b68-4195-adf5-f6d289dfb35d","Comparative Assessment of Methods for Coupling Regional and Local Groundwater Flow Models: A Case Study in the Beijing Plain, China","Liu, S. (TU Delft Water Resources; IHE Delft Institute for Water Education); Zhou, Yangxiao (IHE Delft Institute for Water Education; Hebei University of Geosciences); Xie, Mingzhao (IHE Delft Institute for Water Education); McClain, M.E. (TU Delft Water Resources; IHE Delft Institute for Water Education); Wang, Xu Sheng (China University of Geosciences)","","2021","A coupled regional and local model is required when groundwater flow and solute transport are to be simulated in local areas of interest with a finer grid while regional aquifer boundary and major stresses should be retained with a coarser grid. The coupled model should also maintain interactions between the regional and local flow systems. In the Beijing Plain (China), assessment of managed aquifer recharge (MAR), groundwater pollution caused by rivers, capture zone of well fields, and land subsidence at the cone of depression requires a coupled regional and local model. This study evaluates three methods for coupling regional and local flow models for simulating MAR in the Chaobai River catchment in the Beijing Plain. These methods are the conventional grid refinement (CGR) method, the local grid refinement (LGR) method and the unstructured grid (USG) method. The assessment included the comparison of the complexity of the coupled model construction, the goodness of fit of the computed and observed groundwater heads, the consistency of regional and local groundwater budgets, and the capture zone of a well filed influenced by the MAR site. The results indicated that the CGR method based on MODFLOW-2005 is the easiest to implement the coupled model, capable of reproducing regional and local groundwater heads and budget, and already coupled with density and viscosity dependent model codes for transport simulation. However, the CGR method inherits shortcomings of finite difference grids to create multiple local models with inefficient computing efforts. The USG method based on MODFLOW-USG has the advantage of creating multi-scale models and is flexible to simulate rivers, wells, irregular boundaries, heterogeneities and the MAR site. However, it is more difficult to construct the coupled models with the unstructured grids, therefore, a good graphic user interface is necessary for efficient model construction. The LGR method based on MODFLOW-LGR can be used to create multiple local models in uniform aquifer systems. So far, little effort has been devoted to upgrade the LGR method for complex aquifer structures and develop the coupled transport models.","Grid refinement; Groundwater modeling; Multi-scale model","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:29069771-fe02-4ced-9910-ba8670ffa88e","http://resolver.tudelft.nl/uuid:29069771-fe02-4ced-9910-ba8670ffa88e","Coordination Control of Power Flow Controller and Hybrid DC Circuit Breaker in MVDC Distribution Networks","Liao, Jianquan (Sichuan University); Zhou, Niancheng (Chongqing University); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Purgat, P. (TU Delft DC systems, Energy conversion & Storage); Wang, Qianggang (Chongqing University); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2021","The two main challenges of medium voltage direct current (MVDC) distribution network are the flexible control of power flow (PF) and fault protection. In this paper, the power flow controller (PFC) is introduced to regulate the PF and inhibit the fault current during the DC fault. The coordination strategy of series-parallel PFC (SP-PFC) and hybrid DC circuit breaker (DCCB) is proposed. By regulating the polarity and magnitude of SP-PFC output voltage during the fault, the rising speed of fault current can be suppressed so as to reduce the breaking current of hybrid DCCB. The access mode of SP-PFC to the MVDC distribution network and its topology are analyzed, and the coordination strategy between SP-PFC and hybrid DCCB is investigated. Moreover, the emergency control and bypass control strategies of SP-PFC are developed. On this basis, the mathematical model of SP-PFC in different fault stages is derived. With the equivalent model of SP-PFC, the fault current of the MVDC distribution network can be calculated accurately. A simulation model of the MVDC distribution network containing SP-PFC is established in MATLAB/Simulink. The fault current calculation result is compared with the simulation result, and the effectiveness of the proposed coordination strategy is verified.","DC circuit breaker (DCCB); Medium voltage direct current (MVDC) distribution network; fault current; power flow controller (PFC)","en","journal article","","","","","","","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:69060e4e-c4a2-4b7c-b253-345b87746ff2","http://resolver.tudelft.nl/uuid:69060e4e-c4a2-4b7c-b253-345b87746ff2","An optimal control approach of integrating traffic signals and cooperative vehicle trajectories at intersections","Liu, M. (TU Delft Transport and Planning); Zhao, J. (University of Shanghai for Science and Technology); Hoogendoorn, S.P. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning)","","2021","An integrated approach for optimising traffic signals and cooperative vehicle trajectories at urban intersections is proposed. The upper layer determines the optimal signals using enumeration and the lower layer optimises trajectories under each feasible signal plan. In the lower layer, platoon accelerations are optimised considering comfort and delay while satisfying motion constraints and safe requirements. The red phase is enforced as a logic constraint, which restricts vehicles to stay behind the stop-line. Typical platoon manoeuvres such as split and approach can be included in the lower layer. The integrated control approach is adaptive to traffic demands and flexible in incorporating different traffic movements during multiple signal phases. The controller performance is verified by simulation of three designed scenarios. The comparison with trajectory optimization and signal optimization demonstrates the advantages on throughput, fuel economy, delay and vehicle stops, and reveals insights into the optimal patterns on signals and trajectories.","cooperative vehicles; optimal control; signalised intersections; Trajectory planning","en","journal article","","","","","","","","","","Transport and Planning","Transport and Planning","","",""
"uuid:bb382924-46ae-49ac-b0a7-4d502d4c45fe","http://resolver.tudelft.nl/uuid:bb382924-46ae-49ac-b0a7-4d502d4c45fe","Effect of reactive aggregate on the early age reaction of water-glass activated slag/fly ash mortars","Wang, Wei (University of Tokyo); Zhang, Shizhe (TU Delft Materials and Environment); Ye, G. (TU Delft Materials and Environment); Noguchi, Takafumi (University of Tokyo)","Ye, Guang (editor); Dong, Hua (editor); Liu, Jiaping (editor); Schlangen, Erik (editor); Miao, Changwen (editor)","2021","Alkali activated materials (AAMs) have received worldwide attention due to its lower embodied energy and environmental impact than that of traditional cementitious materials. However, the activators with high alkalinity may raise the risk of alkali silica reaction (ASR) induced deterioration when reactive aggregates are used, which thereby limits the commercial use of AAMs. Not speaking the ASR induced long-term expansion, the early-age reaction of AAMs prepared with reactive aggregates is largely unknown. In this paper, isothermal calorimetry, thermogravimetry (TG) and mercury intrusion porosimetry (MIP) were adopted to study the heat evolution, mineralogical changes and pore structures of early-age ordinary Portland cement (OPC) mortar and water-glass activated slag/fly ash mortars. In each system, emphasis were made to understand the differences between mixtures prepared with standard inert quartz sands and reactive fine aggregates. The results show that the mortars prepared with reactive aggregates generated more heat in the wetting and dissolution stage. Particularly, the water-glass activated slag mortar presented the highest heat flow peak. Meanwhile, the results of TG illustrate that higher amount of reaction products were formed in water-glass activated mortars prepared with reactive aggregates than that with inert quartz sands. These findings suggest that the reactive aggregates are evidently involved in the early-age alkaline reaction of AAMs system.","Alkaline activation; Alkali-silica reaction; Early-age; Heat evolution; Pore structure","en","conference paper","Delft University of Technology","","","","","","","","","","Materials and Environment","","",""
"uuid:bf953287-d14a-4b94-8c91-6c930dfc1ac3","http://resolver.tudelft.nl/uuid:bf953287-d14a-4b94-8c91-6c930dfc1ac3","Accelerating Building Energy Retrofitting with BIM-Enabled BREEAM-NL Assessment","Simhachalam, V. (Student TU Delft); Wang, T. (TU Delft Design & Construction Management); Liu, Y. (TU Delft Integral Design & Management); Wamelink, J.W.F. (TU Delft Design & Construction Management); Montenegro, Lorena (Deerns Consulting Engineers); Van Gorp, Geert (Deerns Consulting Engineers)","","2021","The Paris Agreement requires building retrofitting practices to be more efficient and effective. However, the current practice for building energy retrofitting is lacking behind, and one reason for that is the time-consuming process of energy credit evaluation. Energy performance assessment such as BREEAM-NL in the Netherlands could apply a more automatic approach with the help of building information modelling (BIM) for an efficient building energy retrofitting evaluation process. However, to what extent BIM can help in accelerating energy performance evaluation in the BREEAM-NL certification process is under-examined. This paper first combines literature findings with practical interviews from a case study organization to present a holistic overview of the potential for automating energy-related credits evaluation in BREEAM-NL using BIM. To understand the possible impacts of such transition, a responsible, accountable, consulted, and informed (RACI) matrix is developed to map the impacts on different actors involved. Furthermore, to help practitioners in an organizational context to adopt a BIM-enabled energy credits assessment workflow, the case study organization is studied to (1) understand their current BIM use status; (2) propose a suitable starting point to take toward a BIM-enabled energy performance assessment for building energy retrofitting. Finally, the proposed starting point is demonstrated using a customized application, and the project team’s feedback is used to verify its efficiency and future directions are identified.","BREEAM‐NL; Building energy retrofitting; Building information modelling (BIM); Energy performance evaluation; Energy transition; RACI matrix","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:92c4f25e-137c-4e4a-9407-708e0a588c55","http://resolver.tudelft.nl/uuid:92c4f25e-137c-4e4a-9407-708e0a588c55","A Hybrid Submicroscopic-Microscopic Traffic Flow Simulation Framework","Mullakkal-Babu, F.A. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning); Shyrokau, B. (TU Delft Intelligent Vehicles); Happee, R. (TU Delft Intelligent Vehicles)","","2021","Current lane-based microscopic traffic simulators combine car-following and lane changing logic to describe the (often discrete) lateral vehicle motion on multi-lane road segments. However, the simulated lateral trajectories are physically unplausible and inside-lane behavior such as lane-keeping and curve negotiation cannot be modelled. In this work, we integrate lateral vehicle dynamics and yaw motion into a traffic simulation framework, aiming to describe lateral motion and vehicle interactions with more precision. The resulting framework consists of two coupled layers, an upper tactical level that plans maneuvers such as lane-changing; and a lower operational layer with a control module (steering and acceleration control) that operates in a closed loop with the bicycle model of vehicle dynamics. The feedback mechanism between the layers allows for dynamic trajectory re-planning. Unlike the microscopic traffic models, the proposed framework accounts for lateral vehicle dynamics and yaw motion; provides additional variables such as vehicle heading and front wheel steering angle; and is hence termed as submicroscopic. Case study results demonstrate the power of the framework to include lateral maneuvers such as curve negotiation, corrective steering, lane change abortion and fragmented lane changing. The framework was operationalized to model multi-lane traffic flow consisting of human-driven vehicles. At the macroscopic level, the traffic flow simulation can reproduce phenomena such as capacity drop. Thus the framework preserves the properties of the component models and at the same time describe the continuous 2-D planar movement of vehicles.","Traffic model; submicroscopic; microscopic; hybrid; multilane","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-11-06","","","Transport and Planning","","",""
"uuid:99a59249-9ce2-42f0-97f5-0194d477dd46","http://resolver.tudelft.nl/uuid:99a59249-9ce2-42f0-97f5-0194d477dd46","High-performance Reservoir Simulator for Energy Transition Applications","Khait, M. (TU Delft Reservoir Engineering); Wang, Y. (TU Delft Reservoir Engineering); Lyu, X. (TU Delft Reservoir Engineering); Voskov, D.V. (TU Delft Reservoir Engineering; Stanford University)","","2021","Alternative to CPU computing architectures, such as GPU, continue to evolve increasing the gap in peak memory bandwidth achievable on a conventional workstation or laptop. Such architectures are attractive for reservoir simulation, which performance is generally bounded by system memory bandwidth. However, to harvest the benefit of a new architecture, the source code must be inevitably rewritten, sometimes almost completely. One of the biggest challenges here is to refactor the Jacobian assembly which typically involves large volumes of code and complex data processing. We demonstrate an effective and general way to simplify the linearization stage extracting complex physics-related computations from the main simulation loop and leaving only an algebraic multi-linear interpolation kernel instead. In this work, we provide the detailed description of simulation performance benefits from execution of the entire nonlinear loop on the GPU platform. We evaluate the computational performance of Delft Advanced Research Terra Simulator (DARTS) for various energy transition subsurface applications of practical interest on both CPU and GPU platforms, comparing particular workflow phases including Jacobian assembly and linear system solution with both stages of the Constraint Pressure Residual preconditioner.","","en","conference paper","EAGE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-05-01","","","Reservoir Engineering","","",""
"uuid:f36b7b9e-0ead-4273-b8aa-4866eaeeda8f","http://resolver.tudelft.nl/uuid:f36b7b9e-0ead-4273-b8aa-4866eaeeda8f","Review of Partial Discharge Activity Considering Very-Low Frequency and Damped Applied Voltage","Ghaffarian Niasar, M. (TU Delft DC systems, Energy conversion & Storage); Wang, Xiaolei (China Southern Power Grid; Guangdong University of Technology); Kiiza, Respicius Clemence (Dar es Salaam Institute of Technology)","","2021","When detecting the presence of partial discharge (PD) activity in the insulation system in high-voltage equipment, the excitation voltages at variable frequency have been widely used instead of power-frequency (50/60 Hz) sinusoidal voltage in order to reduce the charging power. This work reviews the relevant research on PD activity at very low frequency (VLF) method, including sinusoidal or cosine-rectangular voltage shape, and damped AC (DAC) method. Based on the research history and development status, some major PD characteristics, such as PD inception voltage (PDIV), PD amplitude, PD charge, PD phase-resolved pattern, and several hot issues, such as surface charge decay and statistical time lag, have been discussed. Moreover, the advantages, disadvantages, and applied conditions of two reviewed methods has been summarized. Finally, the prospects have been made on the main development trends of this research field in the future.","Damped AC method; Partial discharge; Very low frequency method","en","journal article","","","","","","","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:5c782f6f-8604-49fa-b374-c7f24757f3af","http://resolver.tudelft.nl/uuid:5c782f6f-8604-49fa-b374-c7f24757f3af","An Investigation on the Current Collection Quality of Railway Pantograph-catenary Systems with Contact Wire Wear Degradations","Song, Yang (Norwegian University of Science and Technology (NTNU)); Wang, H. (TU Delft Railway Engineering); Liu, Zhigang (Southwest Jiaotong University)","","2021","In railway pantograph-catenary systems, the contact surfaces undergo wear in long-term operations, directly affecting interaction performance and potentially deteriorating the current collection quality. The effect of contact wire wear (CWW) on the current collection quality should be evaluated to understand the system's health status in operations. This article presents a stochastic analysis of the pantograph-catenary interaction performance with different levels of CWW based on four years of measurement data. The power spectral density (PSD) estimation is carried out on the measured CWW to obtain their frequency representations. The random time histories of CWW are generated based on the PSDs. A nonlinear finite element model of catenary with a lumped-mass pantograph is built. Using the Monte Carlo method, the stochastic analysis of pantograph-catenary contact force is carried out to investigate the distribution and dispersion of assessment indices with different levels of CWW. The results indicate that the CWW mainly affects the maximum and minimum contact forces instead of the contact force standard deviation. The optimal pantograph-catenary interaction performance is observed certain years after CWW is formed, depending on the traffic density of the railway line, which is at the second year in the presented case study. Then, the performance declines with an increase in service time. Also, higher operating speed causes a more significant dispersion in assessment indices representing a lower current collection quality, particularly at the maximum operating speed (70% of the catenary wave propagation speed).","Contact Force; Contact Wire Wear (CWW); Current Collection Quality; Electrified Railway; Pantograph-catenary Interaction; Stochastic Analysis","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-11-10","","","Railway Engineering","","",""
"uuid:5ce6b416-ef81-41b6-adf9-8456cf455992","http://resolver.tudelft.nl/uuid:5ce6b416-ef81-41b6-adf9-8456cf455992","Show and speak: Directly synthesize spoken description of images","Wang, X. (TU Delft Multimedia Computing; Xi’an Jiaotong University); Feng, S. (TU Delft Multimedia Computing); Zhu, Jihua (Xi’an Jiaotong University); Hasegawa-Johnson, Mark (University of Illinois at Urbana-Champaign); Scharenborg, O.E. (TU Delft Multimedia Computing)","","2021","This paper proposes a new model, referred to as the show and speak (SAS) model that, for the first time, is able to directly synthesize spoken descriptions of images, bypassing the need for any text or phonemes. The basic structure of SAS is an encoder-decoder architecture that takes an image as input and predicts the spectrogram of speech that describes this image. The final speech audio is obtained from the predicted spectrogram via WaveNet. Extensive experiments on the public benchmark database Flickr8k demonstrate that the proposed SAS is able to synthesize natural spoken descriptions for images, indicating that synthesizing spoken descriptions for images while bypassing text and phonemes is feasible.","Encoder-decoder; Image captioning; Image-to-speech; Sequence-to-sequence; Speech synthesis","en","conference paper","IEEE","","","","","Accepted author manuscript","","","","","Multimedia Computing","","",""
"uuid:b1ff1c8d-b8cb-45e9-9b46-870e28c2c7ac","http://resolver.tudelft.nl/uuid:b1ff1c8d-b8cb-45e9-9b46-870e28c2c7ac","A digital platform for facilitating personalized dementia care in nursing homes: Formative evaluation study","Wang, G. (TU Delft Applied Ergonomics and Design); Albayrak, A. (TU Delft Applied Ergonomics and Design); Kortuem, G.W. (TU Delft Internet of Things); van der Cammen, T.J.M. (TU Delft Applied Ergonomics and Design)","","2021","Background: Care personalization is key to the well-being of people with dementia according to person-centered care. With the development of the internet of things, a large quantity of personal data can be collected securely and reliably, which has the potential to facilitate care personalization for people with dementia. Yet, there are limited assistive technologies developed for this purpose, and the user acceptance of assistive technologies is low in nursing homes. Therefore, through a data-enabled design approach, a digital platform was developed for helping the care team in a nursing home to personalize dementia care, specifically in the management of behavioral and psychological dementia symptoms. Objective: This study aimed to evaluate the digital platform in a real-life context with potential users from the following two aspects: (1) to explore if the digital platform could help with generating insights on the current state of each person with dementia and (2) to gather feedback on the digital platform from the care team. Methods: The digital platform was deployed in the nursing home for 7 weeks and the data collected were visualized and presented to the care team via the digital platform. The visualizations were analyzed by the researchers for pattern detection. Meanwhile, the care team was asked to examine the visualizations and were interviewed for the following: (1) if any insights and actions were generated from the examination, (2) the usefulness of the digital platform, and (3) the improvements they would like to see. Results: The data collected on the digital platform demonstrated its potential for pattern detection. Insights were generated by the care team and categorized into “client level,” “ward level,” and “team level.” The corresponding actions taken by the care team were classified into “investigation” and “implementation.” User acceptance varied across the care team, and three aspects of improvement for the digital platform were identified. Conclusions: By evaluating the digital platform, this study gained insights on applying data-enabled design for personalizing dementia care; besides, it offers future researchers some recommendations on how to integrate assistive technologies in the nursing home context.","Assistive technology; Care management; Data visualizations; Data-driven design; Data-enabled design; Health care design; Human-centered design; Internet of things; People with dementia; Person-centered care; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Applied Ergonomics and Design","","",""
"uuid:ac7ff407-1cc9-4113-a69b-cb3b6f04a4b6","http://resolver.tudelft.nl/uuid:ac7ff407-1cc9-4113-a69b-cb3b6f04a4b6","Restoring the top-of-atmosphere reflectance during solar eclipses: a proof of concept with the UV absorbing aerosol index measured by TROPOMI","Trees, V.J.H. (TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI)); Wang, P. (Royal Netherlands Meteorological Institute (KNMI)); Stammes, P. (Royal Netherlands Meteorological Institute (KNMI))","","2021","During a solar eclipse the solar irradiance reaching the top of the atmosphere (TOA) is reduced in the Moon shadow. The solar irradiance is commonly measured by Earth observation satellites before the start of the solar eclipse and is not corrected for this reduction, which results in a decrease in the computed TOA reflectances. Consequently, air quality products that are derived from TOA reflectance spectra, such as the ultraviolet (UV) absorbing aerosol index (AAI), are distorted or undefined in the shadow of the Moon. The availability of air quality satellite data in the penumbral and antumbral shadow during solar eclipses, however, is of particular interest to users studying the atmospheric response to solar eclipses. Given the time and location of a point on the Earth's surface, we explain how to compute the obscuration during a solar eclipse, taking into account wavelength-dependent solar limb darkening. With the calculated obscuration fractions, we restore the TOA reflectances and the AAI in the penumbral shadow during the annular solar eclipses on 26 December 2019 and 21 June 2020 measured by the TROPOMI/S5P instrument. We compare the calculated obscuration to the estimated obscuration using an uneclipsed orbit. In the corrected products, the signature of the Moon shadow disappeared, but only if wavelength-dependent solar limb darkening is taken into account. We find that the Moon shadow anomaly in the uncorrected AAI is caused by a reduction of the measured reflectance at 380 nm, rather than a colour change of the measured light. We restore common AAI features such as the sunglint and desert dust, and we confirm the restored AAI feature on 21 June 2020 at the Taklamakan Desert by measurements of the GOME-2C satellite instrument on the same day but outside the Moon shadow. No indication of local absorbing aerosol changes caused by the eclipses was found. We conclude that the correction method of this paper can be used to detect real AAI rising phenomena during a solar eclipse and has the potential to restore any other product that is derived from TOA reflectance spectra. This would resolve the solar eclipse anomalies in satellite air quality measurements in the penumbra and antumbra and would allow for studying the effect of the eclipse obscuration on the composition of the Earth's atmosphere from space.","","en","journal article","","","","","","","","","","","Atmospheric Remote Sensing","","",""
"uuid:b4b46aaa-57f3-421a-a03d-7c6df5d20f4b","http://resolver.tudelft.nl/uuid:b4b46aaa-57f3-421a-a03d-7c6df5d20f4b","Systems thinking approach for improving maintenance management of discrete rail assets: a review and future perspectives","Shang, Y. (TU Delft Integral Design & Management); Nogal Macho, M. (TU Delft Integral Design & Management); Wang, Haoyu (TU Delft Mechanics and Physics of Structures); Wolfert, A.R.M. (TU Delft Integral Design & Management)","","2021","Performance evaluation and maintenance planning are gaining importance with ageing rail infrastructure and increasing demand on track safety and continuous availability. The discrete/point railway assets (e.g. bridges, level crossings) together with extended track sections constitute the main railway network infrastructure. The former has important implications in train safety, riding comfort and operating expenditures due to local intensified degradation and plays a role in effective network capacity due to their large quantity. The heterogeneity in asset features and operating environment also adds difficulties to efficient maintenance planning of multiple discrete assets. The current review screens the issue to level crossings, as little concern has been engaged to this asset type, and draws together different perspectives related to their maintenance management. The systems thinking approach is integrated and two levels of asset management (i.e. micro- and macro-level) are used to structure the synthesis, which are interdependent and synergistic. Two major approaches, namely, the mechanistic and data-driven modelling are synthesised. Both contribute to the maintenance knowledge and their comparisons are elaborated. Limitations in existing studies are identified and directions for future research are provided, aiming to contribute to a more refined ‘inspection and diagnosis’ process to properly capture the local track issues and move towards system-level maintenance approach for multiple level crossings.","Data-driven modelling; differential settlement; level crossing; railway maintenance; track geometry degradation; transition zone","en","journal article","","","","","","","","","","","Integral Design & Management","","",""
"uuid:2721c211-a0c6-4b15-afb2-a26abd5ab0ed","http://resolver.tudelft.nl/uuid:2721c211-a0c6-4b15-afb2-a26abd5ab0ed","Hydrosedimentological Response to Estuarine Deepening: Conceptual Analysis","Winterwerp, J.C. (TU Delft Environmental Fluid Mechanics); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2021","This paper describes the effects of anthropogenic deepening of tidal rivers in a conceptual way, with focus on tidal distortion and the residual transport of coarse sediment, driven by asymmetries in peak velocity. The rivers under consideration are fairly small, with small river discharge, and may have irregular hypsometry, with substantial intertidal area, or not. Residual sediment transport is driven by asymmetries in tidal velocity (horizontal tide), which is, however, difficult to establish in general. This paper discusses how and under which cases asymmetries in tidal elevations (vertical tide) can provide appropriate information on residual sediment transport. It is argued that deepening may induce a competition between an increase in tidal amplitude by amplification and a reduction in the asymmetry itself. Linear analysis shows that tidal asymmetry may show irregular behavior locally even for regular river configurations. It is therefore expected that these irregularities become larger in natural and engineered rivers. Analysis of local asymmetries may therefore be misleading in assessing the river's response to deepening with respect to the overall residual sediment transport and the river's morphology. Thus analysis of the overall morphodynamic response of a tidal river to tidal asymmetry, as affected by deepening, requires integration of the nonlinear effects along the entire river. It is argued that tidal asymmetry can be quantified by determining the difference in travel times of the high and low waters at any location within the river. This also implies that tidal water level variations and their asymmetries are governed by the entire tidal volume up-river of the cross section under consideration. River discharge further complicates the analyses by affecting residual water flows, effective hydraulic drag, tidal asymmetry, and mean water level. These effects reduce in response to deepening. However, salinity intrusion and gravitational circulation increase with deepening. We believe that assessing the (long-term) effects of deepening a fairway in a tidal river or estuary requires the use of process-based numerical models to account for all these nonlinear interactions, next to appropriate data collection. The current paper may help in analyzing and interpreting the numerical results.","Deepening; Residual sediment transport; Tidal asymmetry; Tidal river","en","journal article","","","","","","Accepted Author Manuscript","","","","","Environmental Fluid Mechanics","","",""
"uuid:0d29ced7-fa73-4087-abb8-648f711998ee","http://resolver.tudelft.nl/uuid:0d29ced7-fa73-4087-abb8-648f711998ee","Characterizing the Composition of Sand and Mud Suspensions in Coastal and Estuarine Environments Using Combined Optical and Acoustic Measurements","Pearson, S.G. (TU Delft Coastal Engineering; TU Delft Environmental Fluid Mechanics; Deltares); Verney, Romaric (Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Tran, Duc (Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)); Hendriks, H.C.M. (TU Delft Environmental Fluid Mechanics; Deltares); Jacquet, Matthias (Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2021","Quantifying and characterizing suspended sediment is essential to successful monitoring and management of estuaries and coastal environments. To quantify suspended sediment, optical and acoustic backscatter instruments are often used. Optical backscatter systems are more sensitive to mud particles (<63 μm) and flocs, whereas acoustic backscatter systems are more responsive to larger sand grains (>63 μm). It is thus challenging to estimate the relative proportion of sand or mud in environments where both types of sediment are present. The suspended sediment concentration measured by these devices depends on the composition of that sediment, thus it is also difficult to confidently measure concentration with a single instrument when the composition varies and extensive calibration is not possible. The objective of this paper is to develop a methodology for characterizing the relative proportions of sand and mud in mixed sediment suspensions by comparing the response of simultaneous optical and acoustic measurements. We derive a sediment composition index (SCI) that is used to directly predict the relative fraction of sand in suspension. Here, we verify the theoretical response of these optical and acoustic instruments in laboratory experiments and successfully apply this approach to field measurements from Ameland ebb-tidal delta (the Netherlands). Increasing sand content decreases SCI, which was verified in laboratory experiments. A reduction in SCI appears during more energetic conditions when sand resuspension is expected. Conversely, the SCI increases in calmer conditions when sand settles out, leaving behind mud. This approach provides crucial knowledge of suspended sediment composition in mixed sediment environments.","suspended sediment composition; optical backscatter; acoustic backscatter; coastal sediment dynamics; sand; fine sediment","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:d9db74f7-97d2-4d17-b970-efec2902b32e","http://resolver.tudelft.nl/uuid:d9db74f7-97d2-4d17-b970-efec2902b32e","Tracking fluorescent and ferrimagnetic sediment tracers on an energetic ebb-tidal delta to monitor grain size-selective dispersal","Pearson, S.G. (TU Delft Coastal Engineering; TU Delft Environmental Fluid Mechanics; Deltares); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Poleykett, Jack (Partrac Ltd.); Wright, Matthew (Partrac Ltd.); Black, Kevin (Partrac Ltd.); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2021","Sediment tracer studies use uniquely identifiable particles to track the pathways and fate of individual sand or silt grains in marine environments. These techniques are best applied to assess connectivity between potential sediment sources and sinks, such as between a sand nourishment and an ecologically sensitive area. Significant challenges exist when applying sediment tracing techniques to further understanding of systems with complicated hydrodynamic, sediment, and morphological regimes. Ebb-tidal deltas are highly dynamic coastal environments shaped by the complex interplay of waves and tides, but have been under-explored. In this study, we use dual signature (fluorescent and ferrimagnetic) sediment tracers to simulate the dispersal of dredged sediment placed as a sand nourishment on an energetic ebb-tidal delta (at Ameland Inlet, the Netherlands). After deployment, sediment dispersal and grain size sorting behaviour were monitored via the collection of seabed grab samples and magnetic sampling of sediment transported in suspension. The tracer content within collected samples were put in context with hydrodynamic conditions observed during the study period. Here we show that the use of such dual signature tracers, in addition to novel tracer recovery and analysis techniques, enables the dispersal of sediment to be monitored even in such complex settings and energetic conditions as an ebb-tidal delta. Our observations show that tracers transported in suspension are significantly finer than tracers that accumulated in the seabed. These suggest that preferential transport as a function of grain size is a key process in shaping the morphology of ebb-tidal deltas and thus governing the dispersal of sand nourishments there. The findings of this study and the approach used here provide valuable tools for assessing the baseline conditions of complex coastal environments today, and for planning the interventions which may be necessary in future responses to climate change. Lessons learned from the application of sediment tracers in this study are provided to assist future researchers and practitioners in applying this technique in dynamic coastal environments.","Sediment tracers nourishment sand transport","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:4889aa60-5b6e-44ff-854a-03435661e359","http://resolver.tudelft.nl/uuid:4889aa60-5b6e-44ff-854a-03435661e359","Intelligent UAV Swarm Cooperation for Multiple Targets Tracking","Zhou, Longyu (University of Electronic Science and Technology of China); Leng, Supeng (University of Electronic Science and Technology of China); Liu, Qiang (University of Electronic Science and Technology of China; School of Information and Communication Engineering, Chengdu); Wang, Q. (TU Delft Embedded Systems)","","2021","With the advantages of easy deployment and flexible usage, Unmanned Aerial Vehicle (UAV) has advanced the Multi-Target Tracking (MTT) applications. The UAV-MTT system has great potentials to execute dull, dangerous, and critical missions for frontier defense and security. A key challenge in UAV-MTT is how to coordinate multiple UAVs to track diverse invading targets accurately and consecutively. In this paper, we propose a UAV swarm-based cooperative tracking architecture to systematically improve the UAV tracking performance. We design an intelligent UAV swarm-based cooperative algorithm for consecutive target tracking and physical collision avoidance. Moreover, we design an efficient cooperative algorithm to predict the trajectory of invading targets accurately. Our simulation results demonstrate that the swarm behaviors stay stable in realistic scenarios with perturbing obstacles. Compared with state-of-the-art solutions such as the matched deep Q-network, our algorithms can increase tracking accuracy by 60%, reduce tracking delay by 23%, and achieve physical collision-avoidance during the tracking process.","Mobile target tracking; prediction; scheduling; unmanned-aerial-vehicle (UAV) swarm intelligence (SI)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-13","","","Embedded Systems","","",""
"uuid:cc14b078-bba2-47d0-b0a5-6af8d3aeff51","http://resolver.tudelft.nl/uuid:cc14b078-bba2-47d0-b0a5-6af8d3aeff51","A Looseness Detection Method for Railway Catenary Fasteners based on Reinforcement Learning Refined Localization","Zhong, Junping (Southwest Jiaotong University); Liu, Zhigang (Southwest Jiaotong University); Wang, H. (TU Delft Railway Engineering); Liu, Wenqiang (Southwest Jiaotong University); Yang, Cheng (Southwest Jiaotong University); Han, Zhiwei (Southwest Jiaotong University); Nunez, Alfredo (TU Delft Railway Engineering)","","2021","Brace sleeve (BS) fasteners, i.e., nut and bolt, are small components but play essential roles in fixing BS and cantilever in railway catenary system. They are commonly inspected by onboard cameras using computer vision to ensure the safety of railway operation. However, most BS fasteners cannot be directly localized because they are too small in the inspection images. Instead, the BS is first localized for detecting the BS fastener. This leads to a new problem that the localized BS boxes may not contain the complete BS fasteners due to low localization accuracy, making it infeasible to further diagnose the fastener conditions. To tackle this problem, this article proposes a novel pipeline for BS fastener looseness diagnosis. First, the competitive deep learning model Faster RCNN ResNet101 is used to coarsely localize BSs. Second, an action-driven reinforcement learning agent is adopted to refine the coarse-localized boxes through a dynamic position searching process. Then, BS fasteners are extracted from the refined localized BS image by the deep segmentation model YOLACT++, which is fast and interpretable. Finally, a looseness diagnosis criterion based on segmented information are proposed. We evaluate the performance of submodels independently and the overall performance of the whole model on a real-life catenary image dataset collected from a high-speed line in China. The test results show that the proposed method is effective for BS looseness detection in railway catenary.","Component segmentation; reinforcement learning (RL); railway catenary fasteners; looseness detection","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-12-07","","","Railway Engineering","","",""
"uuid:b1ba78ac-15c9-4e79-b978-d58c720810b2","http://resolver.tudelft.nl/uuid:b1ba78ac-15c9-4e79-b978-d58c720810b2","Generating Images from Spoken Descriptions","Wang, X. (TU Delft Multimedia Computing; Xi’an Jiaotong University); Qiao, T. (TU Delft Multimedia Computing); Zhu, Jihua (Xi’an Jiaotong University); Hanjalic, A. (TU Delft Intelligent Systems); Scharenborg, O.E. (TU Delft Multimedia Computing)","","2021","Text-based technologies, such as text translation from one language to another, and image captioning, are gaining popularity. However, approximately half of the world's languages are estimated to be lacking a commonly used written form. Consequently, these languages cannot benefit from text-based technologies. This paper presents 1) a new speech technology task, i.e., a speech-to-image generation (S2IG) framework which translates speech descriptions to photo-realistic images 2) without using any text information, thus allowing unwritten languages to potentially benefit from this technology. The proposed speech-to-image framework, referred to as S2IGAN, consists of a speech embedding network and a relation-supervised densely-stacked generative model. The speech embedding network learns speech embeddings with the supervision of corresponding visual information from images. The relation-supervised densely-stacked generative model synthesizes images, conditioned on the speech embeddings produced by the speech embedding network, that are semantically consistent with the corresponding spoken descriptions. Extensive experiments are conducted on four public benchmark databases: two databases that are commonly used in text-to-image generation tasks, i.e., CUB-200 and Oxford-102 for which we created synthesized speech descriptions, and two databases with natural speech descriptions which are often used in the field of cross-modal learning of speech and images, i.e., Flickr8k and Places. Results on these databases demonstrate the effectiveness of the proposed S2IGAN on synthesizing high-quality and semantically-consistent images from the speech signal, yielding a good performance and a solid baseline for the S2IG task.","adversarial learning; Birds; Databases; Electronic mail; Image synthesis; multimodal modelling; Semantics; speech embedding; Speech processing; Speech-to-image generation; Task analysis; speech-to-image generation; Adversarial learning","en","journal article","","","","","","","","","","Intelligent Systems","Multimedia Computing","","",""
"uuid:106e3e52-d0f8-4fde-907f-3fcc72f6347f","http://resolver.tudelft.nl/uuid:106e3e52-d0f8-4fde-907f-3fcc72f6347f","Association in Dense Cell-Free mmWave Networks","Hersyandika, Rizqi (Katholieke Universiteit Leuven); Wang, Q. (TU Delft Embedded Systems); Pollin, Sofie (Katholieke Universiteit Leuven)","","2021","We exploit a dense cell-free mmWave network where User Equipments (UEs) are served by multiple highly directional beams provided by multiple Base Stations (BSs) simultaneously. Such multi-beam scenarios can either offer high spectral efficiency when different information is transmitted through each beam or a diversity gain when each beam transmits the same information. However, this increased spectral efficiency or diversity gain costs a more complex network association phase. A UE requires finding multiple nearby serving BSs and determining the optimal beam pair for each one. Thus, an efficient association process is urgently needed. In this work, we propose a UE-initiated association method for dense cell-free mmWave networks. We design an efficient beam training mechanism with multiple BSs using hybrid beamforming. We evaluate the proposed association method under different network configurations. The simulation results show that compared to traditional solutions, our proposed association method can lead to maximally 100% faster beam training and reduce energy consumption by up to 77%. The proposed UE-initiated association method is also scalable to the number of RF chains and antennas at BSs and UEs, making it very suitable for dense cell-free networks.","Cell-free network; millimeter-wave (mmWave); association; beam training; hybrid beamforming","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-02-17","","","Embedded Systems","","",""
"uuid:dd1d341b-4bdb-4026-8e9d-1eb9864b5d65","http://resolver.tudelft.nl/uuid:dd1d341b-4bdb-4026-8e9d-1eb9864b5d65","A Reconfigurable Graphene-Based Spiking Neural Network Architecture","Wang, H. (TU Delft Computer Engineering); Cucu Laurenciu, N. (TU Delft Computer Engineering); Cotofana, S.D. (TU Delft Computer Engineering)","","2021","In the paper we propose a reconfigurable graphene-based Spiking Neural Network (SNN) architecture and a training methodology for initial synaptic weight values determination. The proposed graphene-based platform is flexible, comprising a programmable synaptic array which can be configured for different initial synaptic weights and plasticity functionalities and a spiking neuronal array, onto which various neural network structures can be mapped according to the application requirements and constraints. To demonstrate the validity of the synaptic weights training methodology and the suitability of the proposed SNN architecture for practical utilization, we consider character recognition and edge detection applications. In each case, the graphene-based platform is configured as per the application tailored SNN topology and initial state and SPICE simulated to evaluate its reaction to the applied input stimuli. For the first application, a 2-layer SNN is used to perform character recognition for 5 vowels. Our simulation indicates that the graphene-based SNN can achieve comparable recognition accuracy with the one delivered by a functionally equivalent Artificial Neural Network. Further, we reconfigure the architecture for a 3-layer SNN to perform edge detection on 2 grayscale images. SPICE simulation results indicate that the edge extraction results are close agreement with the one produced by classical edge detection operators. Our results suggest the feasibility and flexibility of the proposed approach for various application purposes. Moreover, the utilized graphene-based synapses and neurons operate at low supply voltage, consume low energy per spike, and exhibit small footprints, which are desired properties for largescale energy-efficient implementations.","Spiking neural network; character recognition; edge detection; graphene; reconfigurable","en","journal article","","","","","","","","","","","Computer Engineering","","",""
"uuid:4d3d55eb-8b9f-497e-977c-e240fbb99118","http://resolver.tudelft.nl/uuid:4d3d55eb-8b9f-497e-977c-e240fbb99118","Multiple Strategies Differential Privacy on Sparse Tensor Factorization for Network Traffic Analysis in 5G","Wang, Jin (Changsha University of Science and Technology); Han, Hui (Changsha University of Science and Technology); Li, H. (TU Delft Dataintensive Systems); He, Shiming (Changsha University of Science and Technology); Sharma, Pradip Kumar (University of Aberdeen); Chen, Lydia Y. (TU Delft Dataintensive Systems)","","2021","Due to high capacity and fast transmission speed, 5G plays a key role in modern electronic infrastructure. Meanwhile, sparse tensor factorization (STF) is a useful tool for dimension reduction to analyze high-order, high-dimension, and sparse tensor (HOHDST) data, which is transmitted on 5G Internet-of-things (IoT). Hence, HOHDST data relies on STF to obtain complete data and discover rules for real time and accurate analysis. From another view of computation and data security, the current STF solution seeks to improve the computational efficiency but neglects privacy security of the IoT data, e.g., data analysis for network traffic monitor system. To overcome these problems, this article proposes a multiple-strategies differential privacy framework on STF (MDPSTF) for HOHDST network traffic data analysis. MDPSTF comprises three differential privacy (DP) mechanisms, i.e., varepsilon - DP, concentrated DP, and local DP. Furthermore, the theoretical proof of privacy bound is presented. Hence, MDPSTF can provide general data protection for HOHDST network traffic data with high-security promise. We conduct experiments on two real network traffic datasets (Abilene and Ggrave{E}ANT). The experimental results show that MDPSTF has high universality on the various degrees of privacy protection demands and high recovery accuracy for the HOHDST network traffic data.","Differential privacy framework; multiple-strategies privacy protection; network traffic analysis; sparse tensor factorization","en","journal article","","","","","","","","","","","Dataintensive Systems","","",""
"uuid:90caa250-478c-43d3-a1b5-dea587f8d6c0","http://resolver.tudelft.nl/uuid:90caa250-478c-43d3-a1b5-dea587f8d6c0","Quantification of the Li-ion diffusion over an interface coating in all-solid-state batteries via NMR measurements","Liu, M. (TU Delft RST/Storage of Electrochemical Energy); Wang, C. (TU Delft RST/Storage of Electrochemical Energy); Zhao, C. (TU Delft RST/Storage of Electrochemical Energy; Tsinghua University); van der Maas, E.L. (TU Delft RST/Storage of Electrochemical Energy); Lin, Kui (Tsinghua University); Arszelewska, Violetta (TU Delft RST/Storage of Electrochemical Energy); Li, Baohua (Tsinghua University); Ganapathy, S. (TU Delft RID/TS/Instrumenten groep); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2021","A key challenge for solid-state-batteries development is to design electrode-electrolyte interfaces that combine (electro)chemical and mechanical stability with facile Li-ion transport. However, while the solid-electrolyte/electrode interfacial area should be maximized to facilitate the transport of high electrical currents on the one hand, on the other hand, this area should be minimized to reduce the parasitic interfacial reactions and promote the overall cell stability. To improve these aspects simultaneously, we report the use of an interfacial inorganic coating and the study of its impact on the local Li-ion transport over the grain boundaries. Via exchange-NMR measurements, we quantify the equilibrium between the various phases present at the interface between an S-based positive electrode and an inorganic solid-electrolyte. We also demonstrate the beneficial effect of the LiI coating on the all-solid-state cell performances, which leads to efficient sulfur activation and prevention of solid-electrolyte decomposition. Finally, we report 200 cycles with a stable capacity of around 600 mAh g−1 at 0.264 mA cm−2 for a full lab-scale cell comprising of LiI-coated Li2S-based cathode, Li-In alloy anode and Li6PS5Cl solid electrolyte.","OA-Fund TU Delft","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:15c6f200-e3a5-4ddf-a0d4-07f734b6f22e","http://resolver.tudelft.nl/uuid:15c6f200-e3a5-4ddf-a0d4-07f734b6f22e","Author Correction: In-plane selective area InSb–Al nanowire quantum networks (Communications Physics, (2020), 3, 1, (59), 10.1038/s42005-020-0324-4)","op het Veld, R.L.M. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Eindhoven University of Technology; Kavli institute of nanoscience Delft); Xu, D. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Schaller, V. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, Q. (TU Delft QRD/Goswami Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); de Moor, M.W.A. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Hesselmann, Bart (Kavli institute of nanoscience Delft; Student TU Delft); Vermeulen, K.J. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Bommer, J.D.S. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; Microsoft Quantum Lab Delft); Zhang, H. (TU Delft Electronic Components, Technology and Materials; Kavli institute of nanoscience Delft; Tsinghua University; Beijing Academy of Quantum Information Sciences, Beijing)","","2021","The Data availability statement of this article has been modified to add the accession link to the raw data. The old Data availability statement read “Materials and data that support the findings of this research are available within the paper. All data are available from the corresponding author upon request”. This has been replaced by “Materials and data that support the findings of this research are available within the paper. The raw data have been deposited at https://zenodo.org/record/4589484#.YEoEOy1Y7Sd”. This has been corrected in both the HTML and PDF version of the article.","","en","journal article","","","","","","Correction include: The Data availability statement of this article has been modified to add the accession link to the raw data.","","","","","QRD/Kouwenhoven Lab","","",""
"uuid:5212a6c5-c5a6-4925-8f86-49c275f50b22","http://resolver.tudelft.nl/uuid:5212a6c5-c5a6-4925-8f86-49c275f50b22","Efficient long-range conduction in cable bacteria through nickel protein wires","Boschker, H.T.S. (TU Delft BT/Environmental Biotechnology; Universiteit Antwerpen); Cook, Perran L.M. (Monash University); Polerecky, Lubos (Universiteit Utrecht); Eachambadi, Raghavendran Thiruvallur (University of Hasselt); Lozano, Helena (Barcelona Institute of Science and Technology); Hidalgo-Martinez, Silvia (Universiteit Antwerpen); Khalenkow, Dmitry (Universiteit Gent); Wang, Da (Universiteit Antwerpen); Meysman, F.J.R. (TU Delft BT/Environmental Biotechnology; Universiteit Antwerpen)","","2021","Filamentous cable bacteria display long-range electron transport, generating electrical currents over centimeter distances through a highly ordered network of fibers embedded in their cell envelope. The conductivity of these periplasmic wires is exceptionally high for a biological material, but their chemical structure and underlying electron transport mechanism remain unresolved. Here, we combine high-resolution microscopy, spectroscopy, and chemical imaging on individual cable bacterium filaments to demonstrate that the periplasmic wires consist of a conductive protein core surrounded by an insulating protein shell layer. The core proteins contain a sulfur-ligated nickel cofactor, and conductivity decreases when nickel is oxidized or selectively removed. The involvement of nickel as the active metal in biological conduction is remarkable, and suggests a hitherto unknown form of electron transport that enables efficient conduction in centimeter-long protein structures.","","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:e056edc6-a2e5-4f59-99d2-7a9128de2273","http://resolver.tudelft.nl/uuid:e056edc6-a2e5-4f59-99d2-7a9128de2273","Modeling airport congestion contagion by heterogeneous SIS epidemic spreading on airline networks","Ceria, A. (TU Delft Multimedia Computing); Köstler, Klemens (Student TU Delft); Gobardhan, Rommy (Student TU Delft); Wang, H. (TU Delft Multimedia Computing)","","2021","In this work, we explore the possibility of using a heterogeneous Susceptible-Infected-Susceptible SIS spreading process on an airline network to model airport congestion contagion with the objective to reproduce airport vulnerability. We derive the vulnerability of each airport from the US Airport Network data as the congestion probability of each airport. In order to capture diverse flight features between airports, e.g. frequency and duration, we construct three types of airline networks. The infection rate of each link in the SIS spreading process is proportional to its corresponding weight in the underlying airline network constructed. The recovery rate of each node is also heterogeneous, dependent on its node strength in the underlying airline network, which is the total weight of the links incident to the node. Such heterogeneous recovery rate is motivated by the fact that large airports may recover fast from congestion due to their well-equipped infrastructures. The nodal infection probability in the meta-stable state is used as a prediction of the vulnerability of the corresponding airport. We illustrate that our model could reproduce the distribution of nodal vulnerability and rank the airports in vulnerability evidently better than the SIS model whose recovery rate is homogeneous. The vulnerability is the largest at airports whose strength in the airline network is neither too large nor too small. This phenomenon can be captured by our heterogeneous model, but not the homogeneous model where a node with a larger strength has a higher infection probability. This explains partially the out-performance of the heterogeneous model. This proposed congestion contagion model may shed lights on the development of strategies to identify vulnerable airports and to mitigate global congestion by e.g. congestion reduction at selected airports.","","en","journal article","","","","","","","","","","","Multimedia Computing","","",""
"uuid:4b480046-29e5-48da-b8bc-dec3b27d5647","http://resolver.tudelft.nl/uuid:4b480046-29e5-48da-b8bc-dec3b27d5647","Sustainable materials for 3D concrete printing","Bhattacherjee, Shantanu (Indian Institute of Technology Madras); Basavaraj, Anusha S. (Indian Institute of Technology Madras); Rahul, A. V. (Universiteit Gent); Santhanam, Manu (Indian Institute of Technology Madras); Gettu, Ravindra (Indian Institute of Technology Madras); Schlangen, E. (TU Delft Materials and Environment); Chen, Y. (TU Delft Materials and Environment); Copuroglu, Oguzhan (TU Delft Materials and Environment); Wang, Li (Hebei University of Technology)","","2021","This paper explores the sustainability aspects of binders used in concrete 3D concrete printing. Firstly, a prospective approach to conduct sustainability-assessment based on the life cycle of 3D printed structures is presented, which also highlights the importance of considering the functional requirements of the mixes used for 3D printing. The potential of the material production phase is emphasized to enhance the sustainability potential of 3DCP by reducing the embodied impacts. The literature on the different binder systems used for producing 3D printable mixtures is reviewed. This review includes binders based on portland cement and supplementary cementing materials (SCMs) such as fly ash, silica-fume and slag. Also, alternative binders such as geopolymer, calcium sulfo-aluminate cement (CSA), limestone calcined clay cement (LC3) and reactive magnesium oxide systems are explored. Finally, sustainability assessment by quantifying the environmental impacts in terms of energy consumed and CO2 emissions of mixtures is illustrated with different binder systems. This paper underlines the effect of using SCMs and alternative binder systems for improving the sustainability of 3D printed structures.","3D printing; Cementitious binders; Low carbon binder; Low energy binder; Sustainability","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-12-29","","","Materials and Environment","","",""
"uuid:dfe1d866-56c0-471c-8672-c74242bf2e9e","http://resolver.tudelft.nl/uuid:dfe1d866-56c0-471c-8672-c74242bf2e9e","Design and characterization of 2D MXene-based electrode with high-rate capability","Wang, Xuehang (TU Delft RST/Storage of Electrochemical Energy); Bannenberg, L.J. (TU Delft RID/TS/Instrumenten groep; TU Delft RST/Storage of Electrochemical Energy)","","2021","MXenes, two-dimensional transition metal carbides and nitrides, are promising materials for electrochemical energy storage application due to their redox-active surface and flexible interlayer space. Among all reported MXene-based electrodes, some have shown significantly better high-rate energy storage capabilities. Hence, it is crucial to have a systematic understanding on the decisive factors of the rate capability in the MXene family. This article discusses the impact of material properties at three levels, including intralayer composition, interlayer space and morphology, on the charge transfer and ion transport, revealing all the possible rate-limiting factors of MXene-based electrodes. We also describe systematic methods to characterize MXene electrodes as a detailed fundamental understanding of the structural and chemical properties, and the charge storage mechanisms crucial for rationally designing MXene-based electrodes. Graphic abstract: [Figure not available: see fulltext.]","2D MXenes; High-rate capability; Interlayer space; Intralayer compositions; Morphology","en","review","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:e6a8c4b3-c5a5-4ff4-bb8b-6870c9528608","http://resolver.tudelft.nl/uuid:e6a8c4b3-c5a5-4ff4-bb8b-6870c9528608","High-Silica CHA Zeolite Membrane with Ultra-High Selectivity and Irradiation Stability for Krypton/Xenon Separation","Wang, Xuerui (Nanjing Tech University); Zhou, Tao (Nanjing Tech University); Zhang, Ping (Nanjing Tech University); Yan, Wenfu (Jilin University); Li, Yongguo (China Institute for Radiation, Taiyuan); Peng, Li (Nanjing Tech University); Veerman, Dylan (Student TU Delft); Shi, Mengyang (Nanjing Tech University); Gu, Xuehong (Nanjing Tech University); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering)","","2021","Capture and storage of the long-lived 85Kr is an efficient approach to mitigate the emission of volatile radionuclides from the spent nuclear fuel reprocessing facilities. However, it is challenging to separate krypton (Kr) from xenon (Xe) because of the chemical inertness and similar physical properties. Herein we prepared high-silica CHA zeolite membranes with ultra-high selectivity and irradiation stability for Kr/Xe separation. The suitable aperture size and rigid framework endures the membrane a strong size-exclusion effect. The ultrahigh selectivity of 51–152 together with the Kr permeance of 0.7–1.3×10−8 mol m−2 s−1 Pa−1 of high-silica CHA zeolite membranes far surpass the state-of-the-art polymeric membranes. The membrane is among the most stable polycrystalline membranes for separation of humid Kr/Xe mixtures. Together with the excellent irradiation stability, high-silica CHA zeolite membranes pave the way to separate radioactive Kr from Xe for a notable reduction of the volatile nuclear waste storage volume.","CHA zeolite; gas separation; krypton; membrane; xenon","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:602e1728-f7fe-4d6e-a23d-93457277a964","http://resolver.tudelft.nl/uuid:602e1728-f7fe-4d6e-a23d-93457277a964","Improving the Mechanical Properties of Additively Manufactured Micro-Architected Biodegradable Metals","Li, Yageng (University of Science and Technology Beijing); Shi, Jirong (Peking University); Jahr, H. (Medizinische Fakultat und Universitats Klinikum Aachen; Maastricht UMC); Zhou, J. (TU Delft Biomaterials & Tissue Biomechanics); Zadpoor, A.A. (TU Delft Biomaterials & Tissue Biomechanics); Wang, Luning (University of Science and Technology Beijing)","","2021","Additively manufactured (AM) micro-architected biodegradable metals offer a unique combination of properties that are ideal for bone regeneration including biocompatibility, a fully interconnected porous structure, and the possibility to fully regenerate bony defects with native tissue upon biodegradation. Currently, the mechanical properties of AM biodegradable porous metals can only match the values of human trabecular bone, hindering their applications for cortical bone regeneration. So far, different approaches have been applied to improve the mechanical properties of AM biodegradable porous metals. Here, we present the state-of-the-art in AM biodegradable porous metals with a focus on the effects of material composition, geometrical design, AM process, and post-AM treatments on their mechanical properties. We also identify a number of challenges encountered in adopting AM biodegradable porous metals for orthopedic applications from the mechanical viewpoint and suggest some promising areas for future research.","","en","review","","","","","","Accepted Author Manuscript","","2022-10-25","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:04eb4a02-6806-4858-99a9-fb241240565c","http://resolver.tudelft.nl/uuid:04eb4a02-6806-4858-99a9-fb241240565c","Introducing special issue on photocatalysis and photoelectrochemistry","Batista, Victor (Yale University); Li, Can (Dalian Institute of Chemical Physics, Dalian); Smith, W.A. (TU Delft ChemE/Materials for Energy Conversion and Storage); Wang, Dunwei (Boston College)","","2021","","","en","contribution to periodical","","","","","","","","","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:b1654ecb-681e-4a9c-a476-ca29ff226ace","http://resolver.tudelft.nl/uuid:b1654ecb-681e-4a9c-a476-ca29ff226ace","Design and Optimization of Conforming Lattice Structures","Wu, J. (TU Delft Materials and Manufacturing); Wang, W. (TU Delft Materials and Manufacturing; Dalian University of Technology); Gao, Xifeng (Florida State University)","","2021","Inspired by natural cellular materials such as trabecular bone, lattice structures have been developed as a new type of lightweight material. In this paper we present a novel method to design lattice structures that conform with both the principal stress directions and the boundary of the optimized shape. Our method consists of two major steps: the first optimizes concurrently the shape (including its topology) and the distribution of orthotropic lattice materials inside the shape to maximize stiffness under application-specific external loads; the second takes the optimized configuration (i.e., locally-defined orientation, porosity, and anisotropy) of lattice materials from the previous step, and extracts a globally consistent lattice structure by field-aligned parameterization. Our approach is robust and works for both 2D planar and 3D volumetric domains. Numerical results and physical verifications demonstrate remarkable structural properties of conforming lattice structures generated by our method.","3D printing; homogenization; Lattice structures; topology optimization","en","journal article","","","","","","Accepted Author Manuscript","","","","","Materials and Manufacturing","","",""
"uuid:e5edba67-1244-4285-bef6-90090c0f5840","http://resolver.tudelft.nl/uuid:e5edba67-1244-4285-bef6-90090c0f5840","Effect of oxidation ditch and anaerobic-anoxic-oxic processes on CX3R-type disinfection by-product formation during wastewater treatment","Peng, Liqi (Tongji University; Shanghai Institute of Pollution Control and Ecological Security); Wang, Feifei (Shanghai University); Zhang, Di (Tongji University; Shanghai Institute of Pollution Control and Ecological Security); Fang, Chao (Tongji University; Shanghai Institute of Pollution Control and Ecological Security); van der Hoek, J.P. (TU Delft Sanitary Engineering; Waternet); Chu, Wenhai (Tongji University; Shanghai Institute of Pollution Control and Ecological Security)","","2021","The high chlorine dosages in wastewater treatment plants during the COVID-19 pandemic may result in increased formation of disinfection by-products (DBPs), posing great threat to the aquatic ecosystem of the receiving water body and the public health in the downstream area. However, limited information is available on the effect of biological wastewater treatment processes on the formation of CX3R-type DBPs. This study investigated the effect of oxidation ditch (OD) and anaerobic-anoxic-oxic (AAO), two widely used biological wastewater treatment processes, on the formation of five classes of CX3R-type DBPs, including trihalomethanes (THMs), haloacetic acids (HAAs), haloacetaldehydes (HALs), haloacetonitriles (HANs) and halonitromethanes (HNMs), during chlorination. Experimental results showed that biological treatment effectively reduced the dissolved organic carbon (DOC) and UV254, while it increased the dissolved organic nitrogen (DON), and therefore the ratio of DON/DOC. In addition, increases in the contents of soluble microbial product- and humic acid-like matters, and the transformation of high molecular weight (MW) fractions in the dissolved organic matter into low MW fractions were observed after OD and AAO processes. Although biological treatment effectively decreased the formation of Cl-THMs, Cl-HAAs, Cl-HANs and Cl-HNMs, the formation of DBCM, DBAA, BDCAA, DBCAA, DCAL, TCAL and DBAN (where C = chloro, B = bromo, D = di, T = tri) all increased significantly, due to the increased formation reactivity. Moreover, biological treatment increased the ratio of bromide/DOC and bromine incorporation into THMs, HAAs and DHANs except for HALs and THANs. Different from previous studies, this study revealed that biological treatment increased the formation of some DBPs, especially brominated DBPs, despite the efficient removal of organic matters. It provides insights into the DBP risk control in wastewater treatment, particularly during the COVID-19 pandemic.","Disinfection by-products; Wastewater disinfection; Oxidation ditch; Anaerobic-anoxic-oxic; Formation reactivity","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-07-22","","","Sanitary Engineering","","",""
"uuid:8cc8f893-04b6-41c5-8a8e-d7af5002b930","http://resolver.tudelft.nl/uuid:8cc8f893-04b6-41c5-8a8e-d7af5002b930","Incremental Sliding Mode Control for Aeroelastic Launch Vehicles with Propellant Slosh","Mooij, E. (TU Delft Astrodynamics & Space Missions); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics)","","2021","This paper focuses on the attitude control and propellant slosh suppression of aeroelastic launch vehicles. Four candidate controllers are proposed: the Linear Quadratic Regulator (LQR), the Incremental Non-linear Dynamic Inversion (INDI) control, the Incremental Sliding Mode Control (INDI-SMC), and the Feedback Linearisation-based Sliding Mode Control (FL-SMC). Theoretical analyses show INDI itself is unable to deal with under-actuated systems. Therefore, when applied to the launch vehicle directly, it cannot simultaneously track the pitch command and effectively suppress the slosh dynamics. This issue is solved by INDI-SMC, which also has enhanced robustness against both matched and unmatched uncertainties. Furthermore, despite its reduced model dependency, INDI-SMC has better robustness against model uncertainties and external disturbances than FL-SMC. These merits of INDI-SMC are verified by various simulation results. First, when the nominal plant configuration is adopted, the system using INDI-SMC has the smallest pitch-angle tracking error. The slosh motion is also effectively damped out. Second, Monte-Carlo studies are used to test the robustness of LQR, INDI-SMC, and FL-SMC to parametric uncertainties. Among these three controllers, LQR shows the worst performance and largest control-effort outliers. On the contrary, both INDI-SMC and FL-SMC can resist a wider range of perturbations without significant performance degradation. Even so, the tracking and slosh damping performance of INDI-SMC is still the best. Finally, both INDI-SMC and FL-SMC show robustness against unmodeled dynamics, while the robust performance of INDI-SMC is superior.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","Virtual/online event due to COVID-19","","","","","Astrodynamics & Space Missions","","",""
"uuid:955644ad-dc74-41bf-b90e-7097eed6e8a0","http://resolver.tudelft.nl/uuid:955644ad-dc74-41bf-b90e-7097eed6e8a0","Network-Aware Locality Scheduling for Distributed Data Operators in Data Centers","Cheng, Long (North China Electric Power University; Chinese Academy of Sciences); Wang, Ying (Chinese Academy of Sciences); Liu, Qingzhi (Wageningen University & Research); Epema, D.H.J. (TU Delft Dataintensive Systems); Liu, Cheng (Chinese Academy of Sciences); Mao, Ying (Fordham University); Murphy, John (University College Dublin)","","2021","Large data centers are currently the mainstream infrastructures for big data processing. As one of the most fundamental tasks in these environments, the efficient execution of distributed data operators (e.g., join and aggregation) are still challenging current data systems, and one of the key performance issues is network communication time. State-of-the-art methods trying to improve that problem focus on either application-layer data locality optimization to reduce network traffic or on network-layer data flow optimization to increase bandwidth utilization. However, the techniques in the two layers are totally independent from each other, and performance gains from a joint optimization perspective have not yet been explored. In this article, we propose a novel approach called NEAL (NEtwork-Aware Locality scheduling) to bridge this gap, and consequently to further reduce communication time for distributed big data operators. We present the detailed design and implementation of NEAL, and our experimental results demonstrate that NEAL always performs better than current approaches for different workloads and network bandwidth configurations.","Data locality; SDN; big data; coflow scheduling; data centers; distributed operators; metaheuristic","en","journal article","","","","","","Accepted author manuscript","","","","","Dataintensive Systems","","",""
"uuid:dc52d655-d96f-4d0a-adc4-33ae5e0b8a75","http://resolver.tudelft.nl/uuid:dc52d655-d96f-4d0a-adc4-33ae5e0b8a75","The effect of the standing angle on reducing fatigue among prolonged standing workers","Liu, Zhihui (Donghua University); Wang, Li (Donghua University); Kong, Fanlei (Donghua University); Huang, Xia (Donghua University); Tang, Zhi (Donghua University); He, Shi (Donghua University); Vink, P. (TU Delft Materials and Manufacturing)","","2021","BACKGROUND: Many occupations require workers to stand for prolonged periods, which can cause discomfort, pain and even injures. Some supermarkets in life provide a foot pad for checkout staff to let them stand on it at work, thereby reducing standing fatigue caused by standing for a long time. The inclined platform is the same as the foot pad mentioned above. That is, the staff stepped on it and relieved standing fatigue to a certain extent. OBJECTIVE: The study aims to analyze how the standing angle affects fatigue among prolonged standing workers and tries to find an inclined platform with a specific angle to reduce standing fatigue. METHODS: This experiment studied fatigue of the inclined platforms with different angles on prolonged standing workers, eight participants were selected to participate in the test. The plantar pressures and sEMG (Surface Electromyography) were used to collect the physiological information change of prolonged standing participants in the lower limb and waist. The visual analogue scale was used as a subjective method to measure the psychological fatigue. RESULTS AND CONCLUSION: The study highlights the relationship between standing angle and lower limb fatigue. The inclination of the standing platform has different effects on the participants under different time conditions. When participants stand on inclined platforms at 0°, 5° and 10°, the iEMG (Integrated Electromyography) values of the gastrointestinal muscle were not significantly different until the third sampling point (40 minutes). After that self-regulation of lower limb muscles is better when standing on an inclined platform between 5° and 10°, it has a certain effect on alleviating lower limb fatigue. This knowledge is crucial for the design of the inclined working platforms fitting the needs of prolonged standing workers.","inclined platform; lower limb fatigue; Prolonged standing; standing angle; surface electromyography","en","journal article","","","","","","Accepted Author Manuscript","","","","","Materials and Manufacturing","","",""
"uuid:433518dd-b35e-4455-8b7d-58cb4507e34a","http://resolver.tudelft.nl/uuid:433518dd-b35e-4455-8b7d-58cb4507e34a","Nonlinear Incremental Control for Flexible Aircraft Trajectory Tracking and Load Alleviation","Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics); Mkhoyan, T. (TU Delft Aerospace Structures & Computational Mechanics); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics)","","2021","This paper proposes a nonlinear control architecture for flexible aircraft simultaneous trajectory tracking and load alleviation. By exploiting the control redundancy, the gust and maneuver loads are alleviated without degrading the rigid-body command tracking performance. The proposed control architecture contains four cascaded control loops: position control, flight path control, attitude control, and optimal multi-objective wing control. Since the position kinematics are not influenced by model uncertainties, the nonlinear dynamic inversion control is applied. On the contrary, the flight path dynamics are perturbed by both model uncertainties and atmospheric disturbances; thus the incremental sliding mode control is adopted. Lyapunov-based analyses show that this method can simultaneously reduce the model dependency and the minimum possible gains of conventional sliding mode control methods. Moreover, the attitude dynamics are in the strict-feedback form; thus the incremental backstepping sliding mode control is applied. Furthermore, a novel load reference generator is designed to distinguish the necessary loads for performing maneuvers from the excessive loads. The load references are realized by the inner-loop optimal wing controller, while the excessive loads are naturalized by flaps without influencing the outer-loop tracking performance. The merits of the proposed control architecture are verified by trajectory tracking tasks and gust load alleviation tasks in spatial von K\'arm\'an turbulence fields.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","Virtual/online event due to COVID-19","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:0bc0b71f-3b1c-442b-bc35-fc92397c3aee","http://resolver.tudelft.nl/uuid:0bc0b71f-3b1c-442b-bc35-fc92397c3aee","Game Engine-based Point Cloud Visualization and Perception for Situation Awareness of Crisis Indoor Environments","Liu, Zhenyu (Student TU Delft); Fu, Runnan (Student TU Delft); Wang, Linjun (Student TU Delft); Jin, Yuzhen (Student TU Delft); Papakostas, Theodoros (Student TU Delft); Mainelli, Xenia Una (Student TU Delft); Voûte, R.L. (TU Delft GIS Technologie; CGI Nederland B.V); Verbree, E. (TU Delft GIS Technologie)","Basiri, Anahid (editor); Gartner, Georg Gartner (editor); Huang, Haosheng (editor)","2021","Because unknown interior layouts can have serious consequences in time-sensitive situations, crisis response teams request many potential solutions for visualizing indoor environments in crisis scenarios. This research uses a game engine to directly visualize point cloud data input of indoor environments for generating clear interaction between the environment and viewers, to aid decision-making in high-stress moments. The prospective final product is an integration of game-oriented visualization and cartography, hosted within Unreal Engine 4 (UE4), allowing users to navigate throughout an indoor environment, and customizing certain interaction features. The UE4 project consists of 4 modules: data preprocessing, render style, functional module, and user interface. Finally, this research uses a single-floor indoor point cloud dataset collected from a building in Rotterdam, the Netherlands for the implementation.","Game Engine; Unreal Engine 4; 3D Visualization; Situation Awareness; Point Cloud; Indoor Environment; Crisis Scenario","en","conference paper","TU Wien","","","","","","","","","","GIS Technologie","","",""
"uuid:f444f8e7-4893-42c2-9c6d-dbc458f2a318","http://resolver.tudelft.nl/uuid:f444f8e7-4893-42c2-9c6d-dbc458f2a318","Effect of filler on performance of porous asphalt pavement using multiscale finite element method","Du, Cong (Rheinisch-Westfälische Technische Hochschule); Lu, Guoyang (Rheinisch-Westfälische Technische Hochschule); Wang, H. (TU Delft Pavement Engineering); Sun, Yiren (Dalian University of Technology); Liu, Pengfei (Rheinisch-Westfälische Technische Hochschule); Wang, Dawei (Rheinisch-Westfälische Technische Hochschule; Harbin Institute of Technology); Leischner, Sabine (Technische Universität Dresden); Oeser, Markus (Rheinisch-Westfälische Technische Hochschule)","","2021","Porous asphalt (PA) pavements are widely employed in areas with wet climates. As particle enhancement inclusions in asphalt mastic, mineral fillers play essential roles in improving the performance of PA pavements. This study developed a coupled multiscale finite element (FE) model, involving the mesostructure of PA mixture and PA pavement. Four types of mastic properties were employed with four mineral fillers (Granodiorite, Limestone, Dolomite, and Rhyolite) in the mesoscale portion of the pavement model to analyse the effects of filler types on the performance of pavements. The performances (load-bearing capacity, rutting resistance, and ravelling resistance) of pavements with different fillers were identified and ranked, and their correlations with the chemical components of the four fillers were analysed. The computational results showed that pavements with Rhyolite and Granodiorite fillers have higher load-bearing capacities and rutting resistance, while the Limestone and Dolomite fillers can improve the ravelling resistance of the PA pavements. In the correlation analysis, the chemical components Al2O3 and SiO2 play dominant roles in improving the load-bearing capacities and rutting resistance of the PA pavements, and the fillers with high percentages of CaO can improve the ravelling resistance of the PA pavements.","chemical components; correlation analysis; mineral filler; multiscale finite element model; Porous asphalt pavement","en","journal article","","","","","","Accepted Author Manuscript","","2021-08-16","","","Pavement Engineering","","",""
"uuid:7fb2e89c-38ab-4c75-9638-d7ad0a585b23","http://resolver.tudelft.nl/uuid:7fb2e89c-38ab-4c75-9638-d7ad0a585b23","Pseudospectral optimal train control","Goverde, R.M.P. (TU Delft Transport and Planning); Scheepmaker, G.M. (TU Delft Transport and Planning; N.V. Nederlandse Spoorwegen); Wang, P. (TU Delft Transport and Planning)","","2021","In the last decade, pseudospectral methods have become popular for solving optimal control problems. Pseudospectral methods do not need prior knowledge about the optimal control structure and are thus very flexible for problems with complex path constraints, which are common in optimal train control, or train trajectory optimization. Practical optimal train control problems are nonsmooth with discontinuities in the dynamic equations and path constraints corresponding to gradients and speed limits varying along the track. Moreover, optimal train control problems typically include singular solutions with a vanishing Hessian of the associated Hamiltonian. These characteristics make these problems hard to solve and also lead to convergence issues in pseudospectral methods. We propose a computational framework that connects pseudospectral methods with Pontryagin's Maximum Principle allowing flexible computations, verification and validation of the numerical approximations, and improvements of the continuous solution accuracy. We apply the framework to two basic problems in optimal train control: minimum-time train control and energy-efficient train control, and consider cases with short-distance regional trains and long-distance intercity trains for various scenarios including varying gradients, speed limits, and scheduled running time supplements. The framework confirms the flexibility of the pseudospectral method with regards to state, control and mixed algebraic inequality path constraints, and is able to identify conditions that lead to inconsistencies between the necessary optimality conditions and the numerical approximations of the states, costates, and controls. A new approach is proposed to correct the discrete approximations by incorporating implicit equations from the optimality conditions. In particular, the issue of oscillations in the singular solution for energy-efficient driving as computed by the pseudospectral method has been solved.","Optimal train control; Pontryagin's Maximum Principle; Pseudospectral method; Singular solution; Train trajectory optimization","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:fadaa87f-1530-40a6-b244-25b88dae6b78","http://resolver.tudelft.nl/uuid:fadaa87f-1530-40a6-b244-25b88dae6b78","Tuning electron transfer by crystal facet engineering of BiVO4 for boosting visible-light driven photocatalytic reduction of bromate","Liu, Guoshuai (Jiangnan University); Zhu, Yukun (Qingdao University of Technology); Yan, Qun (Jiangnan University; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment); Wang, Han (Jiangnan University); Wu, Peng (Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment); Shen, Yaoliang (Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment); Doekhi-Bennani, Y. (TU Delft Sanitary Engineering)","","2021","Removal of bromate (BrO3−) has gained increasing attention in drinking water treatment process. Photocatalysis technology is an effective strategy for bromate removal. During the photocatalytic reduction of bromate process, the photo-generated electrons are reductive species toward bromate reduction and photo-generated holes responsible for water oxidation. In this study, the monoclinic bismuth vanadate (BiVO4) single crystal was developed as a visible photocatalyst for the effective removal of bromate. The as-synthesized BiVO4 photocatalyst with optimized {010} and {110} facets ratio could achieve almost 100% removal efficiency of BrO3− driven by visible light with a first-order kinetic constant of 0.0368 min−1. As demonstrated by the electron scavenger experiment and density functional theory (DFT) calculations, the exposed facets of BiVO4 should account for the high photocatalytic reduction efficiency. Under visible light illumination, the photo-generated electron and holes were spatially transferred to {010} facets and {110} facets, respectively. The BiVO4 single crystal photocatalyst may serve as an attractive photocatalyst by virtue of its response to the visible light, spatially charge transfer and separation as well as high photocatalytic activity, which will make the removal of BrO3− in water much easier, more economical and more sustainable.","Bismuth vanadate; Bromate; Crystal engineering; Photocatalysis","en","journal article","","","","","","Accepted Author Manuscript","","2023-01-13","","","Sanitary Engineering","","",""
"uuid:301a70da-c750-4f34-8f39-19847e0109ca","http://resolver.tudelft.nl/uuid:301a70da-c750-4f34-8f39-19847e0109ca","Study of loaded versus unloaded measurements in railway track inspection","Wang, Haoyu (TU Delft Mechanics and Physics of Structures; Fugro); Berkers, Jos (Fugro); van den Hurk, Nick (Fugro); Layegh, Nasir Farsad (Fugro)","","2021","To ensure railway operations safe, track geometry parameters, e.g., track gauge, are usually inspected using track geometry cars. The measurement frequency of track geometry cars is low (twice per year) due to high operational costs and track possession. An innovative way to perform track inspection at high frequency and affordable cost is using mobile track inspection systems, which can be easily mounted on passenger or freight trains. Besides track geometry, it also creates a digital copy of railway corridors providing asset managers with the ability to make fully informed decisions on track assets. Differently, the collectors of mobile systems are further away from the axle than track geometry cars, which are regarded as unloaded and loaded measurement respectively. This difference may lead to a discrepancy in measurement results. This paper studies the difference between loaded and unloaded measurements, using experimental and numerical methods. In the experimental research, a section of track was measured using both systems. The track longitudinal level measured using unloaded and loaded methods were compared, and the discrepancy reported. It was found that although the measuring distance can cause discrepancies, the unloaded measurement method still meets the measurement requirement. The largest discrepancies are in track transition zones, which is explained using the numerical method. After that, a case study using the unloaded measurement method is presented, wherein a section of track has been measured every month. The results show the advantages of frequent measurements in track inspections and the potential applications of unloaded track inspections.","Mobile track inspection system; Track geometry; Track geometry car; Track longitudinal level; Unloaded measurement","en","journal article","","","","","","","","","","","Mechanics and Physics of Structures","","",""
"uuid:cc3830da-709c-4621-87bb-a56e32867f89","http://resolver.tudelft.nl/uuid:cc3830da-709c-4621-87bb-a56e32867f89","Unravelling Decision-Making Processes on Location Choices for High-Speed Railway Stations in China: A Comparison of Shenzhen, Lanzhou and Jingmen","Wang, B. (TU Delft Urban Development Management); de Jong, W.M. (Erasmus Universiteit Rotterdam); van Bueren, Ellen (TU Delft Management in the Built Environment); Ersoy, A. (TU Delft Urban Development Management); Chen, Y. (TU Delft Urban Development Management)","","2021","Most High-Speed Railway (HSR) station areas in China can be found at the urban periphery or in suburban areas, a phenomenon that has often been criticised. While debate about the influence these location choices have on the economic and sustainable development of cities rages on, little attention has been paid to the decision-making processes leading to these locations. This paper investigates these processes by comparing HSR stations in three cities: Shenzhen, Lanzhou and Jingmen. Our findings can help actors involved in making location choices develop awareness of different interests and create the conditions for successful development of HSR station areas.","China; decision-making process; HSR station areas; policy networks; transport planning; urban development","en","journal article","","","","","","","","","","Management in the Built Environment","Urban Development Management","","",""
"uuid:c2e211d6-8bea-453c-bd27-601c83f23cec","http://resolver.tudelft.nl/uuid:c2e211d6-8bea-453c-bd27-601c83f23cec","Modeling of multiphase mass and heat transfer in fractured high-enthalpy geothermal systems with advanced discrete fracture methodology","Wang, Y. (TU Delft Reservoir Engineering); de Hoop, S. (TU Delft Applied Geology); Voskov, D.V. (TU Delft Reservoir Engineering; Stanford University); Bruhn, D.F. (TU Delft Reservoir Engineering; German Research Centre for Geosciences); Bertotti, G. (TU Delft Applied Geology)","","2021","Multiphase mass and heat transfer are ubiquitous in the subsurface within manifold applications. The presence of fractures over several scales and complex geometry magnifies the uncertainty of the heat transfer phenomena, which will significantly impact, or even dominate, the dynamic transport process. Capturing the details of fluid and heat transport within the fractured system is beneficial to the subsurface operations. However, accurate modeling methodologies for thermal high-enthalpy multiphase flow within fractured reservoirs are quite limited. In this work, multiphase flow in fractured geothermal reservoirs is numerically investigated. A discrete-fracture model is utilized to describe the fractured system. To characterize the thermal transport process accurately and efficiently, the resolution of discretization is necessarily optimized. A synthetic fracture model is firstly selected to run on different levels of discretization with different initial thermodynamic conditions. A comprehensive analysis is conducted to compare the convergence and computational efficiency of simulations. The numerical scheme is implemented within the Delft Advanced Research Terra Simulator (DARTS), which can provide fast and robust simulation to energy applications in the subsurface. Based on the converged numerical solutions, a thermal Péclet number is defined to characterize the interplay between thermal convection and conduction, which are the two governing mechanisms in geothermal development. Different heat transfer stages are recognized on the Péclet curve in conjunction with production regimes of the synthetic fractured reservoir. A fracture network, sketched and scaled up from a digital map of a realistic outcrop, is then utilized to perform a sensitivity analysis of the key parameters influencing the heat and mass transfer. Thermal propagation and Péclet number are found to be sensitive to flow rate and thermal parameters (e.g., rock heat conductivity and heat capacity). This paper presents a numerical simulation framework for fractured geothermal reservoirs, which provides the necessary procedures for practical investigations regarding geothermal developments with uncertainties.","Discrete-fracture model; High-enthalpy geothermal simulation; Péclet number; Thermal convection and conduction","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:655385c5-eaa0-4a18-b5fe-c16a730f1142","http://resolver.tudelft.nl/uuid:655385c5-eaa0-4a18-b5fe-c16a730f1142","From aircraft tracking data to network delay model: A data-driven approach considering en-route congestion","Lin, Yu (City University of Hong Kong); Li, L. (TU Delft Air Transport & Operations); Ren, Pan (City University of Hong Kong); Wang, Yanjun (Nanjing University of Aeronautics and Astronautics); Szeto, W. Y. (The University of Hong Kong)","","2021","En-route congestion causes delays in air traffic networks and will become more prominent as air traffic demand will continue to increase yet airspace volume cannot grow. However, most existing studies on flight delay modeling do not consider en-route congestion explicitly. In this study, we propose a new flight delay model, Multi-layer Air Traffic Network Delay (MATND) model, to capture the impact of en-route congestion on flight delays over an air traffic network. This model is developed by a data-driven approach, taking aircraft tracking data and flight schedules as inputs to characterize a national air traffic network, as well as a system-level model approach, modeling the delay process based on queueing theory. The two approaches combined make the network delay model a close representation of reality and easy-to-implement for what-if scenario analysis. The proposed MATND model includes 1) a data-driven method to learn a network composed of airports, en-route congestion points, and air corridors from aircraft tracking data, 2) a stochastic and dynamic queuing network model to calculate flight delays and track their propagation at both airports and in en-route congestion areas, in which the delays are computed via a space–time decomposition method. Using one month of historical aircraft tracking data over China's air traffic network, MATND is tested and shows to give an accurate quantification of delays of the national air traffic network. “What-if” scenario analyses are conducted to demonstrate how the proposed model can be used for the evaluation of air traffic network improvement strategies, where the manipulation of reality at such a scale is impossible. Results show that MATND is computationally efficient, well suited for evaluating the impact of policy alternatives on system-wide delay at a macroscopic level.","En-route congestion; Flight delay; Queuing network; Trajectory clustering","en","journal article","","","","","","","","","","","Air Transport & Operations","","",""
"uuid:be7958b4-0b89-4c8f-b952-ddcfb79700ff","http://resolver.tudelft.nl/uuid:be7958b4-0b89-4c8f-b952-ddcfb79700ff","Seasonal Tidal Dynamics in the Qiantang Estuary: The Importance of Morphological Evolution","Xie, Dongfeng (Zhejiang Institute of Hydraulics and Estuary); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2021","Despite the increasing number of studies on the river-tide interactions in estuaries, less attention has been paid to the role of seasonal morphological changes on tidal regime. This study analyzes the seasonal interplay of river and tide in the Qiantang Estuary, China, particularly focusing on the influences of the active morphological evolution induced by the seasonal variation of river discharge. The study is based on the high and low water levels at three representative stations along the estuary and daily river discharge through 2015, an intermediate flow year in which a typical river flood occurred, as well as the bathymetric data measured in April, July and November, 2015. The results show strong seasonal variations of the water level in addition to the spring-neap variation. These variations are obviously due to the interaction between river discharge and tide but can only be fully explained by including the effect of morphological changes. Two types of the influences of the variation of the river discharge on the tidal dynamics in the estuary can be distinguished: one is immediately induced by the high flow and the other continues for a much longer period because of the bed erosion and the following bed recovery. Tidal range in the upper reach can be doubled after the flood because of bed erosion and then decrease under normal discharge periods due to sediment accumulation. Over a relatively short term such as a month or a spring-neap tidal cycle, there exist good relationships between the tidal range, tidal amplification in the upper reach and the tidal range at the mouth, and between the hydraulic head over the upper and lower reaches. Such relationships are unclear if all data over the whole year are considered together, mainly because of the active morphological evolution.","hydraulic head; morphological evolution; qiantang estuary; river floods; tidal dynamics","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:f59b5b31-f890-4d1f-9a2f-aa77bca15333","http://resolver.tudelft.nl/uuid:f59b5b31-f890-4d1f-9a2f-aa77bca15333","An attribute-based model to retrieve storm surge disaster cases","Wang, Ke (Tsinghua University); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Katholieke Universiteit Leuven; Universiteit Antwerpen); Yang, Yongsheng (Tsinghua University); Li, Jian (Tsinghua University); Huang, Quanyi (Tsinghua University)","Adrot, Anouck (editor); Grace, Rob (editor); Moore, Kathleen (editor); Zobel, Christopher W. (editor)","2021","In China, storm surge disasters cause severe damages in coastal regions. One of the most critical tasks is to predict affected regions and their relative damage levels to support decision-making. This study develops a two-stage retrieval model to search the most similar past disaster case to complete prediction. Based on spatial attributes of cases, the top-ranking past cases with a similar location to the target case are selected. Among these past cases, the most similar past case is selected by disaster attribute similarities. Three typical storm surge case studies have been used and implemented into this proposed model, and the results show that all the most affected regions can be predicted. The proposed model simplifies the prediction process and updates results quickly. This study provides valuable information for the government to make real-time response plans.","Affected region prediction; Multiple attributes; Retrieval model; Storm surge disaster","en","conference paper","Information Systems for Crisis Response and Management, ISCRAM","","","","","","","","","","Safety and Security Science","","",""
"uuid:e1d5391b-e01e-40c9-b700-c852b9797b44","http://resolver.tudelft.nl/uuid:e1d5391b-e01e-40c9-b700-c852b9797b44","A New Divergence Method to Quantify Methane Emissions Using Observations of Sentinel-5P TROPOMI","Liu, Mengyao (Royal Netherlands Meteorological Institute (KNMI)); van der A, Ronald (Royal Netherlands Meteorological Institute (KNMI); Nanjing University of Information Sciences and Technology); van Weele, Michiel (Royal Netherlands Meteorological Institute (KNMI)); Eskes, Henk (Royal Netherlands Meteorological Institute (KNMI)); Lu, Xiao (Sun Yat-sen University); Veefkind, j. Pepijn (TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI)); de Laat, Jos (Royal Netherlands Meteorological Institute (KNMI)); Kong, Hao (Peking University); Wang, Jingxu (Ocean University of China)","","2021","We present a new divergence method to estimated methane (CH4) emissions from satellite observed mean mixing ratio of methane (XCH4) by deriving the regional enhancement of XCH4 in the Planetary Boundary Layer (PBL). The applicability is proven by comparing the estimated emissions with its known emission inventory from a 3-month GEOS-Chem simulation. When applied to TROPOspheric Monitoring Instrument observations, sources from well-known oil/gas production areas, livestock farms and wetlands in Texas become clearly visible in the emission maps. The calculated yearly averaged total CH4 emission over the Permian Basin is 3.06 (2.82, 3.78) Tg a−1 for 2019, which is consistent with previous studies and double that of EDGAR v4.3.2 for 2012. Sensitivity tests on PBL heights, on the derived regional background and on wind speeds suggest our divergence method is quite robust. It is also a fast and simple method to estimate the CH4 emissions globally.","divergence; methane emissions; Texas; TROPOMI","en","journal article","","","","","","","","","","","Atmospheric Remote Sensing","","",""
"uuid:7ead3d6c-bfcc-47fa-b161-ad4c12d3969c","http://resolver.tudelft.nl/uuid:7ead3d6c-bfcc-47fa-b161-ad4c12d3969c","Detecting forest response to droughts with global observations of vegetation water content","Konings, Alexandra G. (Stanford University); Saatchi, Sassan S. (California Institute of Technology); Frankenberg, Christian (California Institute of Technology); Keller, Michael (California Institute of Technology; United States Forest Service); Leshyk, Victor (Northern Arizona University); Anderegg, William R.L. (University of Utah); Humphrey, Vincent (California Institute of Technology); Steele-Dunne, S.C. (TU Delft Mathematical Geodesy and Positioning); Wang, Yujie (California Institute of Technology)","","2021","Droughts in a warming climate have become more common and more extreme, making understanding forest responses to water stress increasingly pressing. Analysis of water stress in trees has long focused on water potential in xylem and leaves, which influences stomatal closure and water flow through the soil-plant-atmosphere continuum. At the same time, changes of vegetation water content (VWC) are linked to a range of tree responses, including fluxes of water and carbon, mortality, flammability, and more. Unlike water potential, which requires demanding in situ measurements, VWC can be retrieved from remote sensing measurements, particularly at microwave frequencies using radar and radiometry. Here, we highlight key frontiers through which VWC has the potential to significantly increase our understanding of forest responses to water stress. To validate remote sensing observations of VWC at landscape scale and to better relate them to data assimilation model parameters, we introduce an ecosystem-scale analog of the pressure–volume curve, the non-linear relationship between average leaf or branch water potential and water content commonly used in plant hydraulics. The sources of variability in these ecosystem-scale pressure-volume curves and their relationship to forest response to water stress are discussed. We further show to what extent diel, seasonal, and decadal dynamics of VWC reflect variations in different processes relating the tree response to water stress. VWC can also be used for inferring belowground conditions—which are difficult to impossible to observe directly. Lastly, we discuss how a dedicated geostationary spaceborne observational system for VWC, when combined with existing datasets, can capture diel and seasonal water dynamics to advance the science and applications of global forest vulnerability to future droughts.","drought response; drought-induced tree mortality; microwave remote sensing; pressure–volume; vegetation optical depth; vegetation water content; water potential","en","review","","","","","","","","","","","Mathematical Geodesy and Positioning","","",""
"uuid:dc3b82e4-52b9-47c2-9458-cd8c483f0831","http://resolver.tudelft.nl/uuid:dc3b82e4-52b9-47c2-9458-cd8c483f0831","Development of an adaptive CTM–RPIM method for modeling large deformation problems in geotechnical engineering","Li, Jianguo (University of Chinese Academy of Sciences; Chinese Academy of Sciences); Wang, Bin (University of Chinese Academy of Sciences; Chinese Academy of Sciences); Jiang, Quan (University of Chinese Academy of Sciences; Chinese Academy of Sciences); He, Benguo (Northeastern University); Zhang, Xue (University of Liverpool); Vardon, P.J. (TU Delft Geo-engineering)","","2021","In this paper, a meshfree method called adaptive CTM–RPIM is developed to model geotechnical problems with large deformation. The developed adaptive CTM–RPIM is a combination of the Cartesian transformation method (CTM), the radial point interpolation method (RPIM) and the alpha shape method. To reduce the requirement for meshes, the CTM is adopted to transform domain integrals into line integrals, and the RPIM is applied to construct interpolation functions. The alpha shape method, which is capable of capturing severe boundary evolution due to large deformations, is then introduced into the CTM–RPIM to form the adaptive CTM–RPIM. The accuracy of CTM–RPIM is first verified by considering a cantilever beam under small deformation, where the influence of key parameters on the simulation results is explored. Afterward, the ability of the adaptive CTM–RPIM to handle large deformation problems is demonstrated by simulating cantilever beams with large deformations for which analytical solutions are available. Finally, the ability of the proposed method to model the geotechnical large deformations is illustrated from both quasi-static and dynamic aspects, where a slope failure problem and a footing bearing capacity problem are modeled to evaluate the stability of geotechnical structures; and a 2-D soil collapse experiment using small aluminum bars is simulated to show the method capability in describing the soil flows. These benchmark examples demonstrate that the adaptive CTM–RPIM is a numerical method with broad application prospects for modeling large deformation problems in geotechnical engineering.","Alpha shape method; Cartesian transformation method; Geotechnical engineering; Large deformation; Radial point interpolation method","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-06-07","","","Geo-engineering","","",""
"uuid:c4844fd6-d066-4541-b107-4021c8e1943f","http://resolver.tudelft.nl/uuid:c4844fd6-d066-4541-b107-4021c8e1943f","A study of graphical representations of uncertainty in LCA guide","Tensa, Melissa (Oregon State University); Wang, Jenna (Stanford University); Harris, Roscoe (Stanford University); Faludi, Jeremy (TU Delft Circular Product Design); DuPont, Bryony (Oregon State University)","","2021","This study user-tested different data visualizations for highly uncertain life cycle assessments (LCAs) to determine what best supported decision-making. Precise LCAs can only be performed once designs are finalized, due to the information necessary to complete them, but design changes in such late stages are costly. If designers could have environmental impact data earlier in the process, sustainable design choices could instead be built into the initial designs. We compiled LCAs for various product categories, finding the best means of visualizing the data for online and printable dissemination. Because this LCA data varied widely within each product category, it was necessary to display uncertainty and require users to acknowledge the uncertainty. Here, four different data visualizations were tested with engineering, design, and STEM students and professionals; both quantitative and qualitative analysis determined what visualizations were most favored and forced users to consider uncertainty. We hope that this research helps LCA data be more accessible to designers and engineers in the early phases of design, allowing those without the resources or ability to perform LCA to benefit from it and design more sustainably.","Design engineering; Sustainability; Visualisation","en","journal article","","","","","","","","","","","Circular Product Design","","",""
"uuid:dfe235e7-dbdb-4aae-b843-bda79d8517a4","http://resolver.tudelft.nl/uuid:dfe235e7-dbdb-4aae-b843-bda79d8517a4","Impressed current cathodic protection of chloride-contaminated RC structures with cracking: A numerical study","Guo, Bingbing (Xi'an University of Architecture and Technology); Qiao, Guofu (Harbin Institute of Technology); Li, Z. (TU Delft Materials and Environment); Li, Dongsheng (Dalian University of Technology); Dai, Jinghui (Harbin University of Commerce); Wang, Yan (Xi'an University of Architecture and Technology)","","2021","Impressed current cathodic protection (ICCP) is an effective and direct method for controlling the corrosion of reinforced concrete (RC) structures. However, few investigations related to ICCP in cracked RC structures have been reported. In this study, the effect of cracks in concrete cover on ICCP of chloride-contaminated RC structures was investigated through a numerical model including steel polarisation, electrode reactions, and ionic migration. In the developed numerical model, cracked concrete cover is assumed to consist of sound concrete and cracks, and cracks have their own ionic diffusion coefficients. The results indicate that the ICCP can maintain its ability to remove Cl− if concrete cover does not completely crack. Once the complete cracking in concrete cover occurs, the Cl− removal ability of ICCP would decrease or even disappear. Cracking does not cause any adverse effect on the pH improvement of ICCP. In this case, a stronger cathodic polarisation is recommended.","Cracks; Impressed current cathodic protection; Numerical modelling; Reinforced concrete structures; Steel corrosion","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:cf351f80-caca-482c-985a-2fb14480ae40","http://resolver.tudelft.nl/uuid:cf351f80-caca-482c-985a-2fb14480ae40","The contribution of sand and mud to infilling of tidal basins in response to a closure dam","Colina Alonso, A. (TU Delft Coastal Engineering; Deltares); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Deltares; East China Normal University); Elias, E. P.L. (Deltares); Holthuijsen, S. J. (NIOZ Royal Netherlands Institute for Sea Research); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2021","Human interventions and climate change can heavily influence the large-scale morphological development of tidal basins. This has implications on sediment management strategies, as well as ecological and recreational purposes. Examples of heavily impacted tidal basins are those in the Western Dutch Wadden Sea. The closure of a large sub-basin in 1932 triggered a shift in the sediment budgets of the remaining basins, leading to sediment infilling that is still ongoing. This paper presents a quantitative analysis of the post-closure sediment volumes, differentiating between sand and mud. Analysis of historical sediment composition data combined with bathymetry data revealed that the intervention caused a redistribution of sand and mud sedimentation. The responses of both sediment types differ spatially and temporally. The total infilling of the basins over the last century was substantially caused by mud (~32%, which is much larger than the average mud content in the bed). Initially, large mud volumes accreted in abandoned channels. At present, mud sedimentation along the mainland coast is still ongoing with nearly constant sedimentation rates over the past century, while the net import of sand significantly decreased over time and has been fluctuating around 0 over the last two decades. This research shows the importance of distinguishing between the response of sandy and muddy sediments when analysing the morphodynamic impact of an intervention, since they operate on different time and spatial scales. Sea level rise is currently a major threat for the existence of the Wadden Sea; its future fate will depend on whether the tidal flats are able to keep pace. Our results show that the supply of mud is sufficient to keep pace with the current sea level rise rates.","Closure dam; Human interference; Morphodynamics; Sediment budgets; Tidal basins; Wadden Sea","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:8f29d613-9e61-424c-bda9-91b6d7050599","http://resolver.tudelft.nl/uuid:8f29d613-9e61-424c-bda9-91b6d7050599","The role of H2 in Fe carburization by CO in Fischer-Tropsch catalysts","Chai, Jiachun (Eindhoven University of Technology); Pestman, Robert (Eindhoven University of Technology); Chen, Wei (Eindhoven University of Technology); Dugulan, A.I. (TU Delft RID/TS/Instrumenten groep); Feng, Bo (National Institute of Clean-and-Low-Carbon Energy, Shenhua NICE, Future Science and Technology City, Changping District, Beijing 102211, People's Republic of China); Men, Zhuowu (National Institute of Clean-and-Low-Carbon Energy, Shenhua NICE, Future Science and Technology City, Changping District, Beijing 102211, People's Republic of China); Wang, Peng (Eindhoven University of Technology; National Institute of Clean-and-Low-Carbon Energy, Shenhua NICE, Future Science and Technology City, Changping District, Beijing 102211, People's Republic of China); Hensen, Emiel J.M. (Eindhoven University of Technology)","","2021","The formation of Fe-carbide phases is relevant to the synthesis of Fischer-Tropsch synthesis catalysts. We investigated the carburization of Raney Fe as a model catalyst using spectroscopic and temperature-programmed techniques. IR spectroscopy shows that CO dissociation already occurs at −150 °C, while C diffusion into metallic Fe requires much higher temperature (~180 °C). The carburization rate increases with increasing H2/CO ratio, which can be attributed to the lower overall barrier for O removal as H2O as compared to CO2. O removal frees vacancies that are needed for CO dissociation. The resulting higher C coverage increases the driving force for Fe-carbide formation. A higher driving force leads to predominant formation of the more carbon-rich ε(́)-carbide, while χ-Fe5C2 is formed at lower H2/CO ratio. The removal of surface O appears to be the rate-limiting step under all conditions. Initially, most of deposited C is used for Fe-carbide formation with a small contribution to hydrocarbons formation.","Carburization; Fischer-Tropsch synthesis; Iron; Mechanism; Synthesis gas","en","journal article","","","","","","","","","","","RID/TS/Instrumenten groep","","",""
"uuid:2c178b45-c7f0-4c7b-840f-1753e1f28983","http://resolver.tudelft.nl/uuid:2c178b45-c7f0-4c7b-840f-1753e1f28983","Resilience-based approach to safety barrier performance assessment in process facilities","Sun, Hao (China University of Petroleum (East China)); Wang, Haiqing (China University of Petroleum (East China)); Yang, M. (TU Delft Safety and Security Science); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Universiteit Antwerpen; Katholieke Universiteit Leuven)","","2021","The performance assessment of safety barriers is essential to find vulnerable elements in a safety barrier system. Traditional performance assessment approaches mainly focus on using several static indicators for quantifying the performance of safety barriers. However, with the increasing complexity of the system, emerging hazards are highly uncertain, making it challenging for the static indicators to assess the performance of safety barriers. This paper proposes a resilience−based performance assessment method for safety barriers to overcome this problem. Safety barriers are classified according to their functions first. The dynamic Bayesian network (DBN) is then introduced to calculate the availability function under normal and disruption conditions. The ratio of the system's availability, when affected by the disruption, to the initial availability, is used to determine the absorption capacity of the system. The ratio of the quantity of availability recovery to the total quantity of system represents the adaptation and restoration capacity of the system. The system's resilience is represented by the sum of absorption, adaptation, and restoration capacities. The wax oil hydrogenation process is used to demonstrate the applicability of the proposed methodology.","Availability; Bayesian network; Resilience; Safety barrier management","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-17","","","Safety and Security Science","","",""
"uuid:3cf158cd-c143-4bc8-bb96-7980e401424e","http://resolver.tudelft.nl/uuid:3cf158cd-c143-4bc8-bb96-7980e401424e","The Cancer SENESCopedia: A delineation of cancer cell senescence","Jochems, Fleur (Netherlands Cancer Institute); Thijssen, Bram (Netherlands Cancer Institute); De Conti, Giulia (Netherlands Cancer Institute); Jansen, Robin (Netherlands Cancer Institute); Pogacar, Ziva (Netherlands Cancer Institute); Groot, Kelvin (Netherlands Cancer Institute); Wang, Liqin (Netherlands Cancer Institute); Schepers, Arnout (Netherlands Cancer Institute); Wessels, L.F.A. (TU Delft Pattern Recognition and Bioinformatics; Netherlands Cancer Institute)","","2021","Cellular senescence is characterized as a stable proliferation arrest that can be triggered by multiple stresses. Most knowledge about senescent cells is obtained from studies in primary cells. However, senescence features may be different in cancer cells, since the pathways that are involved in senescence induction are often deregulated in cancer. We report here a comprehensive analysis of the transcriptome and senolytic responses in a panel of 13 cancer cell lines rendered senescent by two distinct compounds. We show that in cancer cells, the response to senolytic agents and the composition of the senescence-associated secretory phenotype are more influenced by the cell of origin than by the senescence trigger. Using machine learning, we establish the SENCAN gene expression classifier for the detection of senescence in cancer cell samples. The expression profiles and senescence classifier are available as an interactive online Cancer SENESCopedia.","ABT-263; cancer; cell cycle; gene expression classifier; SASP; SENCAN; senescence; SENESCopedia; senolytics; transcriptome profiling","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:8121bb36-3124-47c6-a0e1-e902b49ef63f","http://resolver.tudelft.nl/uuid:8121bb36-3124-47c6-a0e1-e902b49ef63f","Maritime broadband communication: Wireless channel measurement and characteristic analysis for offshore waters","Li, Changzhen (Wuhan University of Technology); Yu, Junyi (Samsung Research China); Xue, J. (TU Delft Safety and Security Science); Chen, Wei (Wuhan University of Technology); Wang, Shoufeng (Samsung Research China); Yang, Kun (Zhejiang Ocean University; Super Radio AS)","","2021","For a long time, the development of maritime communication has been restricted by the low data rate, high-latency and high cost of the current communication systems. The upgrade of new generation mobile communication technologies is attracting more and more attention to conduct a shore-based broadband mobile communication network with high-latency and high reliability to serve the maritime industries. This paper presents a solution by means of building a ship-to-infrastructure (S2I) and a ship-to-ship (S2S) wireless communication networks for an offshore region. We characterize the S2I and S2S channels at 5.9 GHz band based on the channel measurements in realistic environments. The channel characteristics, including power delay profile, delay spread, propagation path loss, are extracted and analyzed. In view of the difference between marine and terrestrial communications, we analyze the influencing factors of the offshore water, including effective reflection, divergence and shadowing from the water surface, and diffraction loss caused by the earth curvature. We also predict the power coverage range and the channel capacity for S2I and S2S wireless communications. Finally, the communication performance is evaluated according to the channel measurement and characterization analysis. The research results can be a reference for the construction of maritime communication networks.","Channel measurement; Maritime safety; Performance evaluation; Shore-based maritime communications","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:0c4f72bd-98dc-4a5c-baab-297a2c41817e","http://resolver.tudelft.nl/uuid:0c4f72bd-98dc-4a5c-baab-297a2c41817e","Design, modeling, optimization, manufacturing and testing of variable-angle filament-wound cylinders","Almeida, José Humberto S. (Aalto University; Queen's University Belfast); St-Pierre, Luc (Aalto University); Wang, Z. (TU Delft Aerospace Structures & Computational Mechanics; School of Mechanical and Electrical Engineering; University of Electronic Science and Technology of China); Ribeiro, Marcelo L. (Universidade de São Paulo); Tita, Volnei (Universidade de São Paulo); Amico, Sandro C. (Universidade Federal do Rio Grande do Sul); Castro, Saullo G.P. (TU Delft Aerospace Structures & Computational Mechanics)","","2021","This work demonstrates the potential of manufacturing variable-angle composite cylinders via filament winding (FW), called VAFW. The proposed design strategy allows different filament angles along the axial direction by dividing the cylinder into regions of constant angle called frames. Designs using two, four, or eight frames are herein investigated. A genetic algorithm is applied to optimize each design for maximum axial buckling load. A design with minimum manufacturable filament angle is included in the study. All structures are manufactured and tested under axial compression, with displacements and strains measured by digital image correlation (DIC). The thickness and mid-surface imperfections of the different designs are measured through DIC and used to explain the observed buckling mechanisms. These imperfections are incorporated into a nonlinear numerical model along with a progressive damage analysis. Additionally, a scaling factor is applied on the measured imperfections to enable an imperfection sensitivity study on the proposed designs. The VAFW design shows buckling strength, stiffness, and absorbed energy substantially higher than the constant-angle configuration, attributed to tailored thickness buildup and optimized tow steered angles at particular regions of the cylinder. The experimental and numerical results indicate that VAFW designs can be tailored to postpone buckling so that the material strength can be better exploited.","Buckling; Filament winding; Modeling; Optimization; Variable stiffness; Variable-angle","en","journal article","","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:652032ea-6e1c-4fbb-b36f-20a8d7dbd609","http://resolver.tudelft.nl/uuid:652032ea-6e1c-4fbb-b36f-20a8d7dbd609","Sensing, actuation, and control of the smartx prototype morphing wing in the wind tunnel","Nazeer, N. (TU Delft Structural Integrity & Composites); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics); Groves, R.M. (TU Delft Structural Integrity & Composites)","","2021","This paper presents a study on trailing edge deflection estimation for the SmartX camber morphing wing demonstrator. This demonstrator integrates the technologies of smart sensing, smart actuation and smart controls using a six module distributed morphing concept. The morphing sequence is brought about by two actuators present at both ends of each of the morphing modules. The deflection estimation is carried out by interrogating optical fibers that are bonded on to the wing’s inner surface. A novel application is demonstrated using this method that utilizes the least amount of sensors for load monitoring purposes. The fiber optic sensor data is used to measure the deflections of the modules in the wind tunnel using a multi-modal fiber optic sensing approach and is compared to the deflections estimated by the actuators. Each module is probed by single-mode optical fibers that contain just four grating sensors and consider both bending and torsional deformations. The fiber optic method in this work combines the principles of hybrid interferometry and FBG spectral sensing. The analysis involves an initial calibration procedure outside the wind tunnel followed by experimental testing in the wind tunnel. This method is shown to experimentally achieve an accuracy of 2.8 mm deflection with an error of 9%. The error sources, including actuator dynamics, random errors, and nonlinear mechanical backlash, are identified and discussed.","Actuators; FBG pair; Fiber bragg grating; Morphing wing; Multi-modal sensing; Optical fiber sensing; Servos; Shape sensing; Structural health monitoring; Wind tunnel","en","journal article","","","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:5189a4bb-f45a-45f8-ad5d-94a3d6909f2c","http://resolver.tudelft.nl/uuid:5189a4bb-f45a-45f8-ad5d-94a3d6909f2c","Optimization of light scattering enhancement by gold nanoparticles in fused silica optical fiber","Wang, X. (TU Delft Structural Integrity & Composites); Benedictus, R. (TU Delft Structural Integrity & Composites); Groves, R.M. (TU Delft Structural Integrity & Composites)","","2021","A conventional distributed fiber optic sensing system offers close to linear sensitivity along the fiber length. However gold nanoparticles (NP) have been shown to be able to enhance the contrast ratio to improve the quality of signal detection. The challenge in improving the contrast of reflected signals is to optimise the nanoparticle doping concentration over the densed sensing length to make best use of the distributed fiber sensing hardware. In this paper, light enhancement by spherical gold NPs in the optical fibers was analyzed by considering the size-induced NP refractive index changes. This was achieved by building a new model to relate backscattered light from a gold NP suspension between the optical fiber end tips and backscattered light from gold NPs in the core of the optical fiber. The paper provides a model to determine the optimized sizes and concentrations of NPs for sensing at different desired penetration depths in the optical fiber.","","en","journal article","","","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:2d4a2a08-7f80-4fff-968b-54519c5d0173","http://resolver.tudelft.nl/uuid:2d4a2a08-7f80-4fff-968b-54519c5d0173","Single-Shot Fabrication of Semiconducting–Superconducting Nanowire Devices","Borsoi, F. (TU Delft QCD/Veldhorst Lab; TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); Mazur, G.P. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); van Loo, N. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); Bourdet, L.R. (TU Delft BUS/Quantum Delft; TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); Li, K. (TU Delft BUS/Quantum Delft; TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); Fursina, A. (TU Delft QRD/Kouwenhoven Lab; Microsoft Quantum Lab Delft); Wang, J. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); Levajac, V. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); Memisevic, E. (TU Delft BUS/Quantum Delft; Kavli institute of nanoscience Delft); van Hoogdalem, K.A. (TU Delft BUS/Quantum Delft; Microsoft Quantum Lab Delft); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; Microsoft Quantum Lab Delft); Heedt, S. (TU Delft BUS/Quantum Delft; Microsoft Quantum Lab Delft); Quintero Perez, M. (TU Delft BUS/Quantum Delft; Microsoft Quantum Lab Delft)","","2021","Semiconducting–superconducting hybrids are vital components for the realization of high-performance nanoscale devices. In particular, semiconducting–superconducting nanowires attract widespread interest owing to the possible presence of non-abelian Majorana zero modes, which are quasiparticles that hold promise for topological quantum computing. However, systematic search for Majoranas signatures is challenging because it requires reproducible hybrid devices and reliable fabrication methods. This work introduces a fabrication concept based on shadow walls that enables the in situ, selective, and consecutive depositions of superconductors and normal metals to form normal-superconducting junctions. Crucially, this method allows to realize devices in a single shot, eliminating fabrication steps after the synthesis of the fragile semiconductor/superconductor interface. At the atomic level, all investigated devices reveal a sharp and defect-free semiconducting–superconducting interface and, correspondingly, a hard induced superconducting gap resilient up to 2 T is measured electrically. While the cleanliness of the technique enables systematic studies of topological superconductivity in nanowires, it also allows for the synthesis of advanced nano-devices based on a wide range of material combinations and geometries while maintaining an exceptionally high interface quality.","hybrid devices; interfaces; Josephson junctions; semiconducting nanowires; superconductivity","en","journal article","","","","","","","","","","","QCD/Veldhorst Lab","","",""
"uuid:48fe8e0c-7a19-42f9-9f69-485c712b3eda","http://resolver.tudelft.nl/uuid:48fe8e0c-7a19-42f9-9f69-485c712b3eda","Degradation modeling considering unit-to-unit heterogeneity-A general model and comparative study","Wang, Zhijie (Shanghai University); Zhai, Qingqing (Shanghai University); Chen, P. (TU Delft Delft Institute of Applied Mathematics; TU Delft Statistics)","","2021","The performance of units in the same batch can exhibit considerable heterogeneity due to the variation in the raw materials and fluctuation in the manufacturing process. For products suffering performance degradation in their use, such heterogeneity often results in an increase in the dispersion of the degradation paths of units in a population. The degradation rate of products can be unit-specific and often treated as random effects. This paper develops a novel random-effects Wiener process model to account for the unit-to-unit heterogeneity in the degradation, where the generalized inverse Gaussian (GIG) distribution is used to model the unit-specific degradation rate. The GIG distribution is a very general distribution with broad applications, which includes the inverse Gaussian (IG) distribution and the Gamma distribution as special cases. We investigate the model properties and develop an expectation maximization (EM) algorithm for parameter estimation. By comparing the proposed model with existing models on two real degradation datasets of the infrared LEDs and the GaAs lasers, we show that the proposed model is quite effective for degradation modeling with heterogeneous rates.","EM algorithm; Generalized inverse Gaussian distribution; Heterogeneous degradation; Wiener process model","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-02-01","","","Statistics","","",""
"uuid:bc1b853c-7e8c-4b55-b55d-571f3f3bbeb5","http://resolver.tudelft.nl/uuid:bc1b853c-7e8c-4b55-b55d-571f3f3bbeb5","How properties of low molecular weight model competitors impact organic micropollutant adsorption onto activated carbon at realistically asymmetric concentrations","Wang, Q. (TU Delft Computational Design and Mechanics; Chinese Academy of Sciences; University of Chinese Academy of Sciences); Mitchell, Raja Louisa (Technical University of Berlin); Hofman, Roberta (KWR Water Research Institute); Yu, Jianwei (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Yang, Min (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Rietveld, L.C. (TU Delft Water Management); Zietzschmann, F.E. (TU Delft Sanitary Engineering; Technical University of Berlin; Berliner Wasserbetriebe)","","2021","Low molecular weight (LMW) dissolved organic matter (DOM) is the predominant competitor for adsorption sites against organic micropollutants (OMPs) in activated carbon adsorption. However, top-down approaches using highly complex mixtures of real water DOM do not allow to concisely examine the impacts of specific LMW DOM molecular properties on competitive adsorption. Therefore, we followed a bottom-up approach using fifteen model compounds (mDOM) to elucidate how important DOM characteristics, including hydrophobicity and unsaturated structures (ring, double/triple bond), impact competitiveness. Large concentration asymmetry (~500 μg DOC/μg OMP) made mDOM compounds, which were overall less preferentially adsorbed than OMPs, become competitive against OMPs and inhibit OMP adsorption kinetics by pre-occupation of adsorption sites. Our results revealed that both hydrophobicity interactions and π-interactions increased mDOM competitiveness, while π-interactions outweighed hydrophobic interactions. However, π-interactions could not be satisfactorily evaluated with a parameter such as specific ultraviolet absorbance (SUVA) due to interferences of carboxyl groups in aromatic mDOMs. Instead, mDOM adsorbability, described by mDOM adsorption capacity, proved to be a comprehensive indicator for mDOM competitiveness. To our knowledge, this is the first study that systematically clarifies the impacts of intricately interacting molecular properties on DOM adsorption and the related competition against OMP adsorption. DOM adsorbability may inspire a new fractionation, and assist the further isolation, identification and detailed characterization of LMW DOM competitors in real DOM-containing waters.","Activated carbon; Adsorbability; Competitive adsorption; Complementary adsorption; Dissolved organic matter (DOM); Model compounds","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-18","","Water Management","Computational Design and Mechanics","","",""
"uuid:9032c70c-7390-4fbd-a997-2db77616dfc9","http://resolver.tudelft.nl/uuid:9032c70c-7390-4fbd-a997-2db77616dfc9","Quantification on fuel cell degradation and techno-economic analysis of a hydrogen-based grid-interactive residential energy sharing network with fuel-cell-powered vehicles","He, Yingdong (University of California; Hunan University); Zhou, Yuekuan (The Hong Kong Polytechnic University); Wang, Zhe (Lawrence Berkeley National Laboratory); Liu, Jia (The Hong Kong Polytechnic University); Liu, Zhengxuan (TU Delft Housing Quality and Process Innovation; Hunan University); Zhang, Guoqiang (Hunan University)","","2021","Hydrogen-based (H2-based) interactive energy networks for buildings and transportations provide novel solutions for carbon-neutrality transition, regional energy flexibility and independence on fossil fuel consumption, where vehicle fuel cells are key components for H2-electricity conversion and clean power supply. However, due to the complexity in thermodynamic working environments and frequent on/off operations, the proton exchange membrane fuel cells (PEMFCs) suffer from performance degradation, depending on cabin heat balance and power requirements, and the ignorance of the degradation may lead to the performance overestimation. In order to quantify fuel cell degradation in both daily cruise and vehicle-to-grid (V2G) interactions, this study firstly proposes a two-space cabin thermal model to quantify the ambient temperature of vehicle PEMFCs and the power supply from PEMFCs to vehicle HVAC systems. Afterwards, a stack voltage model is proposed to quantify the fuel cell degradation for multiple purposes, such as daily transportation and V2G interactions. Afterwards, the two models are coupled in a community-level based building-vehicle energy network, consisting of twenty single residential buildings, rooftop PV systems, four hydrogen vehicles (HVs), a H2 station, community-served micro power grid, local main power grid, and local H2 pipelines, located in California, U.S.A. Comparative analysis with and without fuel cell degradation is conducted to study the impact of dynamic fuel cell degradation on the energy flexibility and operating cost. Furthermore, a parametrical analysis is conducted on the integrated HV quantity and the grid feed-in tariff to reach trade-off strategies between associated fuel cell degradation costs and grid import cost savings. The results indicate that, in the proposed hydrogen-based building-vehicle energy network, the total fuel cell degradation is 3.16% per vehicle within one year, where 2.50% and 0.66% are caused by daily transportation and V2G interactions, respectively. Furthermore, in the H2-based residential community, the total fuel cell degradation cost is US$6945.2, accounting for 33.4% of the total operating cost at $20770.61. The sensitivity analysis results showed that, when the HV quantity increases to twenty, the fuel cell degradation of each HV decreases to 2.50%, whereas the total fuel cell degradation cost increases to 42.8% of the total operating cost. Last but not the least, the cost saving by V2G interactions can compensate the fuel cell degradation cost when the grid feed-in tariff is reduced by 40%. Research results can provide basic modelling tools on dynamic fuel cell degradation, in respect to vehicle power supply, vehicle HVAC and V2G interactions, together with techno-economic feasibility analysis, paving path for the development of hydrogen energy for the carbon-neutrality transition.","Cabin thermal model; Distributed hydrogen infrastructure; Fuel cell degradation; Hydrogen energy storage and economy; Solar energy; Wind turbine","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-02-23","","","Housing Quality and Process Innovation","","",""
"uuid:67d15412-58c7-4a5e-9ee3-369297fd7e7d","http://resolver.tudelft.nl/uuid:67d15412-58c7-4a5e-9ee3-369297fd7e7d","Environmental and anthropogenic drivers of surface urban heat island intensity: A case-study in the Yangtze River Delta, China","Wang, Zian (Chinese Academy of Sciences; University of Chinese Academy of Sciences; Sanya Institute of Remote Sensing); Meng, Qingyan (Chinese Academy of Sciences; Sanya Institute of Remote Sensing); Allam, Mona (Chinese Academy of Sciences; National Water Research Center, Egypt); Hu, Die (Chinese Academy of Sciences; Sanya Institute of Remote Sensing); Zhang, Linlin (Chinese Academy of Sciences; Sanya Institute of Remote Sensing); Menenti, M. (TU Delft Optical and Laser Remote Sensing; Chinese Academy of Sciences)","","2021","Nowadays urban climate is a global problem and many studies focused on understanding the relation between urban climate the built-up space using radiometric observations of the land surface temperature to estimate and monitor the surface urban heat island intensity (SUHIs). In this study MODIS land surface temperature (LST) data were used. The Yangtze River Delta Urban Agglomeration (YRDUA), eastern China, was selected as an example to study SUHI and multiple influencing factors in 16 big cities. Anthropogenic factors are considered the most important ones in determining SUHI, while natural factors remain influential. By using stratified random sampling (SRS), 78,085 random points were selected within the 16 cities. Nine influencing factors were selected in this study: distance from building (BD), distance from the main roads (RD), distance from water (WD), digital elevation model product (DEM), gross domestic product (GDP), normalized difference vegetation index product (NDVI), nighttime lighting intensity (NTI), population (POP) and impervious surface area data (%ISA). The SUHI intensity was extracted at each random point as well as the values of the influencing factors, NDVI, DEM, ISA, POP, NTI and GDP. For BD, WD and RD, random points were selected from the water, building and main roads using the near tool in ArcGIS to measure these distances. Boosted regression tree (BRT) model was applied to capture the contributions of the above factors to SUHI. We also applied a different procedure to evaluate the relative influence of Land Use and Land Cover (LULC). The relative influence refers to the contribution of each factor to determine SUHI. The influencing factors were ranked on the basis of the relative influence on SUHI. The results showed that (1) higher SUHI intensity was recorded in Shanghai, Jiaxing and Nanjing cities respectively, while Hangzhou recorded the lowest SUHI. (2) Anthropogenic drivers have slightly higher relative influence on SUHI than natural drivers, i.e. 51.29% and 48.71% respectively. The influence of all drivers on SUHI from high to low is NTI (27.62%), ISA (24.38%), NDVI (12.11%), GDP (7.95%), DEM (7.29%), POP (6.37%), BD (5.33%), WD (4.93%), RD (4.02%). (3) The variation in the socioeconomic level lead to different spatial patterns of different influence factors, further indicating that the overall mean SUHI intensity is affected by the development of the city.","Boosted regression trees; Land surface temperature; Surface urban heat island; Yangtze River Delta","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:91df164c-46b7-44d1-9ae2-001644790d01","http://resolver.tudelft.nl/uuid:91df164c-46b7-44d1-9ae2-001644790d01","Full parity phase diagram of a proximitized nanowire island","Shen, J. (TU Delft Architecture and the Built Environment; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; Chinese Academy of Sciences); Winkler, G. W. (University of California); Borsoi, F. (TU Delft QCD/Veldhorst Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Heedt, S. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; Microsoft Quantum Lab Delft); Levajac, V. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, J. (TU Delft Optical and Laser Remote Sensing; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); van Driel, D. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Bouman, D. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; Microsoft Quantum Lab Delft); van Heck, B. (TU Delft BUS/Quantum Delft; Microsoft Quantum Lab Delft)","","2021","We measure the charge periodicity of Coulomb blockade conductance oscillations of a hybrid InSb-Al island as a function of gate voltage and parallel magnetic field. The periodicity changes from to at a gate-dependent value of the magnetic field, , decreasing from a high to a low limit upon increasing the gate voltage. In the gate voltage region between the two limits, which our numerical simulations indicate to be the most promising for locating Majorana zero modes, we observe correlated oscillations of peak spacings and heights. For positive gate voltages, the transition with low is due to the presence of nontopological states whose energy quickly disperses below the charging energy due to the orbital effect of the magnetic field. Our measurements highlight the importance of a careful exploration of the entire available phase space of a proximitized nanowire as a prerequisite to define future topological qubits.","","en","journal article","","","","","","","","","Architecture and the Built Environment","","QCD/Veldhorst Lab","","",""
"uuid:b2734d80-3504-4553-9be8-673b339a0389","http://resolver.tudelft.nl/uuid:b2734d80-3504-4553-9be8-673b339a0389","Effect of Nb on Microstructural Evolution and Mechanical Properties of Hot-Rolled Quenching and Partitioning Steels Containing Bainite","Chai, Zhisong (Northeastern University); Hu, Jun (Northeastern University); Wang, Chenchong (Northeastern University); Wang, Lingyu (Northeastern University); Sun, Weihua (Shandong Iron & Steel Group Rizhao, Shandong); van der Zwaag, S. (TU Delft Novel Aerospace Materials); Xu, W. (Northeastern University)","","2021","Herein, the effect of Nb content on the phase transformation kinetics, microstructure, and mechanical properties of hot-rolled quenching and partitioning (Q&P) steel is investigated. The characteristics of three C–Mn–Si–Ti steels (0.18C, 2.0Si, 2.6Mn, and 0.015Ti) containing 0, 0.027, or 0.061 wt% Nb are compared. Results reveal that grain boundary pinning by precipitates and Nb solute drag effects refine the austenite grain size during the hot-rolling process; the microstructural refinement is carried over to the final microstructure subjected to the Q&P treatment. The remaining supersaturated Nb suppresses the bainite formation and decreases the final bainite fraction formed in the Q&P process. The microstructural evolution leads to an increase in the ultimate tensile strength (UTS) of the steel containing 0.027 wt% Nb from 1169 to 1228 MPa, while keeping the total elongation at 18%. When the Nb content is increased to 0.061 wt%, the UTS of the steel increases to 1313 MPa, but the elongation at break drops to 16%. The effect is due to the carbon consumption by the Nb precipitates, which causes a decrease in the stability of the retained austenite and reduces the strain hardening at high strain levels.","bainitic transformation; Nb microalloying; quenching and partitioning steel; retained austenite; strength and total elongation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-02-17","","","Novel Aerospace Materials","","",""
"uuid:f420191f-52e0-4d7c-afc3-9d0f164319aa","http://resolver.tudelft.nl/uuid:f420191f-52e0-4d7c-afc3-9d0f164319aa","Influence of Pile Diameter and Aspect Ratio on the Lateral Response of Monopiles in Sand with Different Relative Densities","Wang, H. (TU Delft Geo-engineering; Zhejiang University); Wang, Lizhong (Zhejiang University; Key Laboratory of Offshore Geotechnics and Material of Zhejiang Province); Hong, Yi (Zhejiang University; Key Laboratory of Offshore Geotechnics and Material of Zhejiang Province); Askarinejad, A. (TU Delft Geo-engineering); He, Ben (Power China Huadong Engineering Corporation Limited); Pan, Hualin (Zhejiang Province Energy Group Company Ltd)","","2021","The large-diameter monopiles are the most preferred foundation used in offshore wind farms. However, the influence of pile diameter and aspect ratio on the lateral bearing behavior of monopiles in sand with different relative densities has not been systematically studied. This study presents a series of well-calibrated finite-element (FE) analyses using an advanced state dependent constitutive model. The FE model was first validated against the centrifuge tests on the large-diameter monopiles. Parametric studies were performed on rigid piles with different diameters (D = 4–10 m) and aspect ratios (L/D = 3–7.5) under a wide range of loading heights (e = 5–100 m) in sands with different relative densities (Dr = 40%, 65%, 80%). The API and PISA p-y models were systematically compared and evaluated against the FE simulation results. The numerical results revealed a rigid rotation failure mechanism of the rigid pile, which is independent of pile diameter and aspect ratio. The computed soil pressure coefficient (K = p/Dσ′ v) of different diameter piles at same rotation is a function of z/L (z is depth) rather than z/D. The force–moment diagrams at different deflections were quantified in sands of different relative density. Based on the observed pile–soil interaction mechanism, a simple design model was proposed to calculate the combined capacity of rigid piles.","3D finite element analysis; Combined capacity; Hypoplastic; Large diameter; Monopile; Rigid; Sand","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:e68bebe2-a0ad-45e0-9b7b-43f898ad70f7","http://resolver.tudelft.nl/uuid:e68bebe2-a0ad-45e0-9b7b-43f898ad70f7","Seismic control performance of a three-story frame prototype equipped with semi-active variable stiffness and damping structural joints","Wang, Qinyu (Eindhoven University of Technology); Senatore, Gennaro (Swiss Federal Institute of Technology); Jansen, K.M.B. (TU Delft Emerging Materials; TU Delft Sustainable Design Engineering); Habraken, Arjan (Eindhoven University of Technology); Teuffel, Patrick (Eindhoven University of Technology)","","2021","This paper presents numerical and experimental studies on semi-active seismic response control of structures equipped with variable stiffness and damping structural joints. Such adaptive joints, which are comprised of a shape memory polymer (SMP) core reinforced by an SMP-aramid composite skin, function as load-transfer components as well as semi-active control devices. The SMP core material can transition from a glassy to a rubbery state through thermal actuation resulting in a shift of the structural natural frequencies and a parallel increase of damping ratio, which enables a new semi-active control strategy. Control performance has been evaluated on a three-story frame equipped with 12 adaptive joints and subjected to seismic excitations. Full-transient analysis has shown that when the joints are thermally actuated to the transition temperature (65°C), acceleration and base shear are reduced by up to 62% and 65%, respectively. Shake-table tests have been carried out on a 1/10-scale prototype, confirming that through thermal actuation of the adaptive joints the structural damping ratio increases from 2.6% to 11.3% and the first natural frequency shifts by up to 37%. As the structure becomes more flexible, an increase of displacements and interstory drift might occur. However, depending on the seismic excitation, top-story acceleration and base shear are significantly reduced in the range 43%–50% and 35%–51%, respectively. These results confirm that semi-active control through thermal actuation of variable stiffness and damping structural joints is effective to mitigate the structure response under seismic excitation.","adaptive structures; seismic response control; semi-active control; shake-table test; variable stiffness and damping; viscoelastic material","en","journal article","","","","","","","","","","Sustainable Design Engineering","Emerging Materials","","",""
"uuid:2a29dc7b-66f9-40bc-a39d-48ff4e2f24de","http://resolver.tudelft.nl/uuid:2a29dc7b-66f9-40bc-a39d-48ff4e2f24de","BlendVLC: A cell-free VLC network architecture empowered by beamspot blending","Beysens, Jona (Katholieke Universiteit Leuven); Wang, Q. (TU Delft Embedded Systems); Van Den Abeele, Maxim (Katholieke Universiteit Leuven); Pollin, Sofie (Katholieke Universiteit Leuven)","","2021","In visible light communication (VLC), the quality of communication is primarily dominated by line-of-sight links. To ensure an appropriate link quality anywhere, beamsteering has been proposed where transmitters (TXs) dynamically steer their beams to create beamspots on the users. However, these highly dynamic TXs face the beam tracking problem and result in highly variable illumination. In this work, we propose BlendVLC, a cell-free network architecture to improve the mobility robustness of users by blending the beamspots from both steerable and fixed TXs. We solve the beam tracking by designing a centimeter-level visible light positioning algorithm empowered by a neural network. Relying on this location information, we formulate and solve an optimization problem on the beamspot blending, and design a fast and scalable heuristic for large networks. We build a proof-of-concept testbed as well as a simulator to evaluate BlendVLC. We show that it achieves superior performance compared to denser networks with fully fixed TXs. For example, in a large-scale VLC network of 8 m x 4 m, BlendVLC improves the average system throughput by 30%, while only requiring half the number of TXs.","Beamsteering; Cell-free; Mobility; Positioning; Tracking; Visible light communication","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-02-01","","","Embedded Systems","","",""
"uuid:c4a5b4b7-da40-4437-b89e-f677571ba2ba","http://resolver.tudelft.nl/uuid:c4a5b4b7-da40-4437-b89e-f677571ba2ba","A novel dynamical collaborative optimization method of ship energy consumption based on a spatial and temporal distribution analysis of voyage data","Wang, Kai (Dalian Maritime University); Xu, Hao (Dalian Maritime University); Li, Jiayuan (Dalian Maritime University); Huang, Lianzhong (Dalian Maritime University); Ma, Ranqi (Dalian Maritime University); Jiang, X. (TU Delft Transport Engineering and Logistics); Yuan, Yupeng (MOST; University of Cambridge); Mwero, Ngome A. (Dalian Maritime University; Jomo Kenyatta University of Agriculture and Technology); Sun, Peiting (Dalian Maritime University); Negenborn, R.R. (TU Delft Transport Engineering and Logistics; MOST); Yan, Xinping (MOST)","","2021","It is of significant importance to optimize the energy consumption of ships in order to improve economy and reduce CO2 emissions. However, the energy use of ships is affected by a series of navigational environmental parameters, which have certain spatial and temporal differences and variability. Therefore, the dynamic collaborative optimization method of sailing route and speed, which fully considers the spatial and temporal distribution characteristics of those factors, is of great importance. In this paper, the spatial and temporal distribution characteristics of the environmental factors and their related ship energy consumption profiles are first analyzed. Subsequently, a ship energy consumption model considering various environmental factors is established to realize the prediction of energy use of ships within the navigation region. Then, a novel dynamic collaborative optimization algorithm, which adopts the Model Predictive Control (MPC) strategy and swarm intelligence algorithm, is proposed, to further improve the ship's energy consumption optimization. Finally, a case study is conducted to demonstrate the effectiveness of the proposed method. The results show that the newly developed dynamic collaborative optimization method, which fully considers the continuously time-varying characteristics of environmental and operational parameters, could effectively reduce the energy consumption in comparison to the original operational mode. In addition, the adoption of the MPC strategy produces better performance results compared to the optimization method without the MPC strategy.","energy consumption prediction; intelligent ship; low carbon shipping; Speed optimization; weather routing","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-12-01","","","Transport Engineering and Logistics","","",""
"uuid:d7f4462e-3cce-415c-8ee5-a7bf7688c3da","http://resolver.tudelft.nl/uuid:d7f4462e-3cce-415c-8ee5-a7bf7688c3da","On resonances in transversally vibrating strings induced by an external force and a time-dependent coefficient in a Robin boundary condition","Wang, J. (TU Delft Mathematical Physics; Beijing Institute of Technology); van Horssen, W.T. (TU Delft Mathematical Physics); Wang, Jun-Min (Beijing Institute of Technology)","","2021","In this paper an initial–boundary value problem on a bounded, fixed interval is considered for a one-dimensional and forced string equation subjected to a Dirichlet boundary condition at one end of the string and a Robin boundary condition with a slowly varying time-dependent coefficient at the other end of the string. This problem may serve as a simplified model describing transverse or longitudinal vibrations as well as resonances in axially moving cables for which the length changes in time. By introducing an adapted version of the method of separation of variables, by using averaging and singular perturbation techniques, and by finally using a three time-scales perturbation method, resonances in the problem are detected and accurate, analytical approximations of the solutions of the problem are constructed. It will turn out that small order ɛ excitations can lead to order ɛ responses when the frequency of the external force satisfies certain conditions. Finally, numerical simulations are presented, which are in full agreement with the obtained analytical results.","Interior layer analysis; Multiple-timescales perturbation method; Resonance zone; Robin boundary condition; Time-dependent coefficient","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:4b0db9c3-d702-4851-ba75-bfb6a3eacde6","http://resolver.tudelft.nl/uuid:4b0db9c3-d702-4851-ba75-bfb6a3eacde6","Influential factors on the development of a low-enthalpy geothermal reservoir: A sensitivity study of a realistic field","Wang, Y. (TU Delft Reservoir Engineering); Voskov, D.V. (TU Delft Reservoir Engineering; Stanford University); Khait, M. (TU Delft Reservoir Engineering); Saeid, S. (TU Delft Reservoir Engineering); Bruhn, D.F. (TU Delft Reservoir Engineering; German Research Centre for Geosciences)","","2021","A realistic deep low-enthalpy geothermal reservoir based on real data with high detail and complicated sedimentary structure is utilized to perform sensitivity analyses of the geological features influencing reservoir properties. We perform simulations using the Delft Advanced Research Terra Simulator (DARTS). Compelling numerical performance of DARTS makes it suitable for handling a large ensemble of models including efficient sensitivity and uncertainty analyses. The major finding is that shale facies, generally ignored in hydrocarbon reservoir simulations, can significantly extend the predictive lifetime of geothermal reservoirs exploited by deep well doublets. It is important to accurately account for the shale facies in the simulation, though with an additional computational overhead. The overburden layers can improve doublet performance, but the impact depends on reservoir heterogeneity. In addition, heterogeneity will also divert the flow path with even a minor shift in the well placement. The discharge rate, an essential parameter of geothermal operation strategy, inversely corresponds to the doublet lifetime but positively correlates with the energy production for studied parameter ranges. Low sensitivity of doublet lifetime to vertical-horizontal permeability ratio and permeability-porosity correlation is observed. All these systematic findings for a realistic geothermal field with characterization at unprecedented level of detail can help to provide a general guideline for forward simulation and farther improve the profitability of geothermal energy production in realistic deep geothermal reservoirs through computer-assisted modeling and optimization.","Doublet lifetime; Low-enthalpy geothermal; Numerical simulation; Sensitivity analysis","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:794ec41f-0738-422f-8d77-d50f26500d4b","http://resolver.tudelft.nl/uuid:794ec41f-0738-422f-8d77-d50f26500d4b","Combined effects of elevated temperatures and high strain rates on compressive performance of S30408 austenitic stainless steel","Li, Lijun (Taiyuan University of Technology); Wang, Rui (Taiyuan University of Technology); Zhao, Hui (Taiyuan University of Technology; Tianjin University); Zhang, Haoran (Taiyuan University of Technology); Yan, R. (TU Delft Steel & Composite Structures)","","2021","This paper presents an experimental investigation on the dynamic mechanical performance of S30408 austenitic stainless steel (ASS) under elevated temperatures, which is essential for determining the behaviour of structures made with this type of steel subjected to the coupled fire and impact/explosion. For this purpose, the quasi-static and dynamic compression tests using Split Hopkinson Pressure Bar (SHPB) were conducted under temperatures of 20–600 °C and strain rates from 0.001 to 3000 s−1. In addition, the corresponding microstructures of tested samples were observed. The stress–strain responses, strain rate and temperature effects as well as the microstructural evolutions were analyzed. Test results show that the stress–strain responses are sensitive to the strain rate and temperature. The strain-rate sensitivity coefficient increases as the strain rate and temperature rise. The microstructural observation reveals that the grain dimension declines with an increment of strain rate or a decreasing temperature. Finally, the dynamic compressive stress–strain models for S30408 ASS under 20–600 °C were suggested on the basis of the Johnson-Cook (J-C) model and have been proved to give a reasonable prediction.","Constitutive model; Dynamic response; Elevated temperatures; S30408 austenitic stainless steel; Strain rate","en","journal article","","","","","","Accepted Author Manuscript","","2022-07-28","","","Steel & Composite Structures","","",""
"uuid:181adbe9-de7e-4cda-b569-2917d0969c7b","http://resolver.tudelft.nl/uuid:181adbe9-de7e-4cda-b569-2917d0969c7b","Experimental and numerical study on lateral resistance of frictional sleeper with arrowhead groove","Jing, Guoqing (Beijing Jiaotong University); Jia, W. (TU Delft Railway Engineering); Wang, Xinyu (Beijing Jiaotong University); Markine, V.L. (TU Delft Railway Engineering); Nålsund, Roar (Bane NOR (Norwegian National Rail Administration)); Guo, Y. (TU Delft Railway Engineering)","","2021","To enhance the stability of continuous welded rail (CWR) tracks, frictional sleepers have been developed. The frictional sleepers are new types of sleepers with grooves on the bottom, and different bottom grooves improve lateral resistances at different magnitudes. In this study, single sleeper push test (SSPT) and its model with discrete element method (DEM) were carried out to confirm how much arrowhead groove frictional (AGF) sleeper increases the lateral resistance of ballasted track. The SSPTs were performed to confirm the lateral resistance results, and also to validate and calibrate the DEM models. With the validated models, the groove factors influencing the lateral resistances were studied, including groove sizes (depth, width), arrowhead groove direction and groove numbers. The reason of lateral resistance improvement was studied at mesoscopic level, including the ballast-sleeper contact numbers and contact force chains. Results show that applying the AGF sleeper is able to improve lateral resistance by 7–24%, and it can provide enough lateral resistance after reducing ballast shoulder width from 500 mm to 300 mm. The AGF sleeper can improve the sleeper-ballast interaction by increasing sleeper-ballast contact number. The study is helpful for frictional sleeper design, further improving track stability.","AGF sleeper; Arrowhead groove; Discrete element method; Lateral resistance","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:4a341807-3bad-45b0-adb1-aed96bdee4b2","http://resolver.tudelft.nl/uuid:4a341807-3bad-45b0-adb1-aed96bdee4b2","Effect of ethanol concentration on methane hydrate decomposition: MD simulation insights","Sun, Xiaoliang (China University of Petroleum - Beijing); Zhou, Guanggang (China University of Petroleum - Beijing); Liu, Z. (TU Delft ChemE/Advanced Soft Matter; China University of Petroleum - Beijing); Zhu, Jianwei (China University of Petroleum - Beijing); Guo, Fengzhi (China University of Petroleum - Beijing); Chen, Junqing (China University of Petroleum - Beijing); He, Wenhao (China University of Petroleum - Beijing); Wang, Ning (China University of Petroleum - Beijing); Zhao, Ge (China University of Petroleum - Beijing); Lu, Guiwu (China University of Petroleum - Beijing)","","2021","The controllability of mining is a key factor affecting the commercial application of methane hydrates, and the addition of chemical additives can significantly accelerate the mining process. However, the effect of additive concentration on hydrate decomposition is not yet well understood. In this study, we systematically investigate the effect of ethanol concentration on the decomposition of methane hydrate under varying thermodynamic conditions using molecular dynamics (MD) simulations. To quantitatively characterize the decomposition process and mechanism of methane hydrates, the combination of angular order parameter (AOP), radial distribution function (RDF), mean square displacement (MSD), diffusion coefficients and system energy was for the first time used. The results showed that the addition of ethanol contributed to the formation of methane bubbles and accelerated the decomposition of hydrates. The mass transfer effect of ethanol molecules and the reconstruction of the hydrogen bond network of water molecules determined the stability of hydrates. From 0 to 40 mol% ethanol concentration, the hydrate decomposition increased with increasing the concentration of ethanol. Both increasing the temperature and decreasing the pressure are beneficial to the decomposition of the hydrate system. These results provide the selection of optimal ethanol concentration for the decomposition of methane hydrate and reveal its decomposition mechanism, and shed important light for the controllable production of gas hydrates.","Decomposition; Ethanol concentration; Methane hydrate; Molecular dynamics; Thermodynamics","en","journal article","","","","","","","","","","","ChemE/Advanced Soft Matter","","",""
"uuid:bc719b80-23d8-4376-b510-6a659b308c01","http://resolver.tudelft.nl/uuid:bc719b80-23d8-4376-b510-6a659b308c01","Dependence of tides and river water transport in an estuarine network on river discharge, tidal forcing, geometry and sea level rise","Wang, Jinyang (Universiteit Utrecht); de Swart, Huib E. (Universiteit Utrecht); Dijkstra, Y.M. (TU Delft Mathematical Physics)","","2021","Estuaries are often characterised by a complex network of branching channels, in which the water motion is primarily driven by tides and fresh water discharge. For both scientific reasons and management purposes, it is important to gain more fundamental knowledge about the hydrodynamics in such networks, as well as their implications for turbidity and ecological functioning. A generic 2DV estuarine network model is developed to study tides and river water transport and to understand the dependence of their along-channel and vertical structure on forcings, geometry characteristics and sea level changes. The model is subsequently applied to the Yangtze Estuary to investigate tides and the distribution of river water over channels during dry and wet season, spring tide, as well as prior to and after the formation of Hengsha Passage and the construction of the Deep Waterway Project and sea level rise. Increasing river discharge enhances the friction for tides by increasing both internal and bottom stresses. Changes in tidal forcing are correlated with the friction for both tide and river. A shortcut channel reduces the water level difference in adjacent channels, as well as tidal amplitudes difference. Sea level rise results in larger friction parameters and faster propagation of tides. The distribution of river water transport is hardly affected by above mentioned changes. Model results and current vertical structure are consistent with observations.","Harmonic decomposition; River–tide interaction; Yangtze Estuary","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:392e6400-871c-452c-9bb6-790140906414","http://resolver.tudelft.nl/uuid:392e6400-871c-452c-9bb6-790140906414","Subgeometric hypocoercivity for piecewise-deterministic markov process monte carlo methods","Andrieu, Christophe (University of Bristol); Dobson, P. (TU Delft Statistics); Wang, Andi Q. (University of Bristol)","","2021","We extend the hypocoercivity framework for piecewise-deterministic Markov process (PDMP) Monte Carlo established in [2] to heavy-tailed target distributions, which exhibit subgeometric rates of convergence to equilibrium. We make use of weak Poincaré inequalities, as developed in the work of [15], the ideas of which we adapt to the PDMPs of interest. On the way we report largely potential-independent approaches to bounding explicitly solutions of the Poisson equation of the Langevin diffusion and its first and second derivatives, required here to control various terms arising in the application of the hypocoercivity result.","Hypocoercivity; Markov chain Monte Carlo; Piecewise-deterministic Markov process; Subgeometric convergence","en","journal article","","","","","","","","","","","Statistics","","",""
"uuid:fc3c1730-e0ac-4b53-b606-31596c780dea","http://resolver.tudelft.nl/uuid:fc3c1730-e0ac-4b53-b606-31596c780dea","Learning fine-grained semantics in spoken language using visual grounding","Wang, X. (Xi’an Jiaotong University); Tian, Tian (Student TU Delft); Zhu, Jihua (Xi’an Jiaotong University); Scharenborg, O.E. (TU Delft Multimedia Computing)","","2021","In the case of unwritten languages, acoustic models cannot be trained in the standard way, i.e., using speech and textual transcriptions. Recently, several methods have been proposed to learn speech representations using images, i.e., using visual grounding. Existing studies have focused on scene images. Here, we investigate whether fine-grained semantic information, reflecting the relationship between attributes and objects, can be learned from spoken language. To this end, a Fine-grained Semantic Embedding Network (FSEN) for learning semantic representations of spoken language grounded by fine-grained images is proposed. For training, we propose an efficient objective function, which includes a matching constraint, an adversarial objective, and a classification constraint. The learned speech representations are evaluated using two tasks, i.e., speech-image cross-modal retrieval and speech-to-image generation. On the retrieval task, FSEN outperforms other state-of-the-art methods on both a scene image dataset and two fine-grained datasets. The image generation task shows that the learned speech representations can be used to generate high-quality and semantic-consistent fine-grained images. Learning fine-grained semantics from spoken language via visual grounding is thus possible.","Image generation; Multimodal modelling; Semantic retrieval; Speech representation learning; Visual grounding","en","conference paper","IEEE","","","","","Accepted author manuscript","","","","","Multimedia Computing","","",""
"uuid:e03e6a02-d379-4ab8-981e-bfd328bc95e8","http://resolver.tudelft.nl/uuid:e03e6a02-d379-4ab8-981e-bfd328bc95e8","Proposal and proof-of-principle demonstration of fast-switching broadband frequency shifting for a frequency-multiplexed quantum repeater","Wang, Peng Cheng (Kavli institute of nanoscience Delft; Student TU Delft); Pietx i Casas, O. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Falamarzi Askarani, M. (TU Delft QID/Tittel Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Castro do Amaral, G. (TU Delft BUS/General; TU Delft QID/Hanson Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; PUC-Rio)","","2021","A proposal for fast-switching broadband frequency-shifting technology making use of frequency conversion in a nonlinear crystal is set forth, whereby the shifting is imparted to the converted photons by creating a bank of frequency-displaced pump modes that can be selected by a photonic switch and directed to the nonlinear crystal. Proof-of-principle results show that the expected frequency-shifting operation can be achieved. Even though the dimensions of the currently employed crystal and significant excess loss in the experimental setup prevented conversion of single-photon-level inputs, thorough experimental and theoretical analysis of the noise contribution allowed for estimation of the system performance in an optimized scenario, where the expected signal-to-noise ratio (SNR) for single-photon conversion and frequency shifting can reach up to 25 dB with proper narrowband filtering and state-of-the-art devices. The proposed frequency-shifting solution figures as a promising candidate for applications in frequency-multiplexed quantum repeater architectures with 25 dB output SNR (with 20% conversion efficiency) and capacity for 16 channels spread around a 100 GHz spectral region.","","en","journal article","","","","","","Accepted Author Manuscript","","2022-03-10","","","QCD/Vandersypen Lab","","",""
"uuid:6febb710-4c1b-4102-9bd6-46ba207f6415","http://resolver.tudelft.nl/uuid:6febb710-4c1b-4102-9bd6-46ba207f6415","Public and private value creation using artificial intelligence: An empirical study of AI voice robot users in Chinese public sector","Wang, Changlin (Henan University of Economics and Law); Teo, Thompson S.H. (National University of Singapore); Janssen, M.F.W.H.A. (TU Delft Information and Communication Technology)","","2021","Despite significant theoretical and empirical attention on public value creation in the public sector, the relationship between artificial intelligence (AI) use and value creation from the citizen perspective remains poorly understood. We ground our study in Moore's public value management to examine the relationship between AI use and value creation. We conceptually categorize public service value into public value and private value. We use procedural justice and trust in government as indicators of public value and, based on motivation theory, we use perceived usefulness and perceived enjoyment as indicators of private value. A field survey of 492 AI voice robot users in China was conducted to test our model. The results indicated that the effective use of AI voice robots was significantly associated with private value and procedural justice. However, the relationship between the effective use of AI and trust in government was not found to be significant. Surprisingly, the respondents indicated that private value had a greater effect on overall value creation than public value. This contrasts with the common idea that value creation from the government perspective suggests that social objectives requiring public value are more important to citizens. The results also show that gender and citizens with different experiences show different AI usage behaviors.","Artificial intelligence; Private value; Public value; Value creation; Voice robot","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-02-09","","","Information and Communication Technology","","",""
"uuid:7f36fa70-2bbf-41f0-9d84-e8fd08ed592d","http://resolver.tudelft.nl/uuid:7f36fa70-2bbf-41f0-9d84-e8fd08ed592d","Seasonal variation of floc population influenced by the presence of algae in the Changjiang (Yangtze River) Estuary","Deng, Z. (TU Delft Coastal Engineering; East China Normal University); He, Qing (East China Normal University); Chassagne, C. (TU Delft Environmental Fluid Mechanics; Deltares); Wang, Zhengbing (TU Delft Coastal Engineering; East China Normal University; Deltares)","","2021","The variation of the floc population in the Changjiang Estuary has been studied for both winter and summer season as a function of the presence of living (micro)algae. The influence of algae has been characterized through the use of the chlorophyll-a concentration to suspended sediment concentration (CC/SSC) ratio. Two whole tidal cycle sampling campaigns were carried out and a full set of parameters (particle size distribution, particle concentration, salinity, velocities, chlorophyll-a concentration) was recorded as function of time for 6 vertical depths. It is found that the floc population can be described by three particle classes. The two most dynamic classes (microflocs and macroflocs) co-exist in the water column. It was nonetheless found, due to the correlation between CC/SSC and particle sizes that the system is at steady state, both in summer and in winter. This can be explained by the limited flocculation ability between the classes due to their segregation in the water column. In winter, macroflocs are found at the top of the water column but their amount and size are very reduced with a mean CC/SSC value of 13 ± 11 μg g−1. In summer, algae-rich macroflocs are abundant at the top of the water column with a mean CC/SSC value of 21 ± 18 μg g−1, especially at flood tide. Microflocs, on the other hand, have a higher density and are generally found deeper in the water column. At high water slack, both macroflocs and microflocs will settle but will never catch-up. The fact that the flocs are at steady-state in terms of flocculation is of importance for sediment transport modelling.","Algae; Changjiang Estuary; Floc size; Flocculation; Particle size distribution; Seasonal variation; Tidal variation; Yangtze Estuary","en","journal article","","","","","","Accepted Author Manuscript","","2023-08-18","","","Coastal Engineering","","",""
"uuid:1fb4e494-5f33-4695-88cc-e687dc961558","http://resolver.tudelft.nl/uuid:1fb4e494-5f33-4695-88cc-e687dc961558","Study of Sediment Transport in a Tidal Channel-Shoal System: Lateral Effects and Slack-Water Dynamics","Zhou, Z. (TU Delft Coastal Engineering; East China Normal University); Ge, Jianzhong (East China Normal University; Institute of Eco-Chongming (IEC)); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; East China Normal University; Deltares); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); Kuai, Y. (TU Delft Coastal Engineering); Ding, Pingxing (East China Normal University)","","2021","Lateral flows redistribute sediment and influence the morphodynamics of channel-shoal systems. However, our understanding of lateral transport of suspended sediment during high and low water slack is still fairly limited, especially in engineered estuaries. Human interventions such as dike-groyne structures influence lateral exchange mechanisms. The present study aims to unravel these mechanisms in a heavily engineered, turbid channel-shoal system in the Changjiang Estuary, using a high-resolution unstructured-grid three-dimensional model and in situ observations. Analysis of model results reveals two typical transport patterns during slack-water conditions, that is, shoal-to-channel transport during low water slack and channel-to-shoal transport during high water slack. A momentum balance analysis is carried out to explain mechanisms driving the lateral transport of suspended sediment during high water slack, revealing the importance of lateral pressure gradients, Coriolis force, and the curvature-induced term. Groyne fields play a crucial role in sediment transport, especially during low water slack. A model scenario in which one groyne is removed reveals that groyne fields strongly influence lateral sediment transport. The decomposition of the sediment transport flux reveals that the turbidity maximum is shaped by a balance between seaward advection by residual flows, and landward transport by tidal pumping and gravitational circulation. Within the turbidity maximum, sediment is laterally redistributed by lateral flows during slack-water conditions, greatly influencing estuarine channel morphology.","groyne fields; lateral flow; numerical model; salinity gradient; sediment transport; slack-water dynamics","en","journal article","","","","","","","","2021-08-20","","","Coastal Engineering","","",""
"uuid:b6b9c657-3d3d-42bf-83fb-47d50b5be514","http://resolver.tudelft.nl/uuid:b6b9c657-3d3d-42bf-83fb-47d50b5be514","Computation-Efficient Parameter Estimation for a High-Resolution Global Tide and Surge Model","Wang, X. (TU Delft Mathematical Physics); Verlaan, M. (TU Delft Mathematical Physics; Deltares); Apecechea, Maialen Irazoqui (Deltares); Lin, H.X. (TU Delft Mathematical Physics)","","2021","In this study, a computation-efficient parameter estimation scheme for high-resolution global tide models is developed. The method is applied to Global Tide and Surge Model with an unstructured grid with a resolution of about 2.5 km in the coastal area and about 4.9 million cells. The estimation algorithm uses an iterative least squares method, known as DUD. We use time-series derived from the FES2014 tidal database in deep water as observations to estimate corrections to the bathymetry. Although the model and estimation algorithm run in parallel, directly applying of DUD would not be affordable computationally. To reduce the computational demand, a coarse-to-fine strategy is proposed by using output from a coarser model to replace the fine model. There are two approaches; One is completely replacing the fine model with a coarser model during calibration (Coarse Calibration) and the second is Coarse Incremental Calibration, that replaces the output increments between the initial model and model with modified parameters by coarser grid model simulations. To further reduce the computation time, the parameter dimension is reduced from O(106) to O(102) based on sensitivity analysis, which greatly reduces the required number of model simulations and storage. In combination, these methods form an efficient optimization strategy. Experiments show that the accuracy of the tidal representation can be improved significantly at affordable cost. Validation for other time-periods and using coastal tide-gauges shows that the accuracy is improved significantly. However, the calibration period of two weeks is short and leads to some over-fitting of the model.","bathymetry calibration and validation; coarse-to-fine strategy; computational time reduction; global parameter estimation; global tide and surge model; sensitivity analysis","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:35a4bd15-370b-4a2b-a16a-46de714e7d66","http://resolver.tudelft.nl/uuid:35a4bd15-370b-4a2b-a16a-46de714e7d66","Integrating van der Waals materials on paper substrates for electrical and optical applications","Zhang, Wenliang (Instituto de Ciencia de Materiales de Madrid (ICMM)); Zhao, Qinghua (Instituto de Ciencia de Materiales de Madrid (ICMM); Northwestern Polytechnical University; Ministry of Industry and Information Technology Xi an); Munuera, Carmen (Instituto de Ciencia de Materiales de Madrid (ICMM)); Lee, M. (TU Delft QN/Steeneken Lab; Kavli institute of nanoscience Delft); Flores, Eduardo (Universidad Nacional Autónoma de México); van der Zant, H.S.J. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft); Wang, Tao (Northwestern Polytechnical University; Ministry of Industry and Information Technology Xi an); Frisenda, Riccardo (Instituto de Ciencia de Materiales de Madrid (ICMM)); Castellanos-Gomez, Andres (Instituto de Ciencia de Materiales de Madrid (ICMM))","","2021","Paper holds the promise to replace silicon substrates in applications like internet of things or disposable electronics that require ultra-low-cost electronic components and an environmentally friendly electronic waste management. In the last years, spurred by the abovementioned properties of paper as a substrate and the exceptional electronic, mechanical and optical properties of van der Waals (vdW) materials, many research groups have worked towards the integration of vdW materials-based devices on paper. Recently, a method to deposit a continuous film of densely packed interconnects of vdW materials on paper by simply rubbing the vdW crystals against the rough surface of paper has been presented. This method utilizes the weak interlayer vdW interactions and allows cleaving of the crystals into micro platelets through the abrasion against the paper. Here, we aim to illustrate the general character and the potential of this technique by fabricating films of 39 different vdW materials (including superconductors, semi-metals, semiconductors, and insulators) on standard copy paper. We have thoroughly characterized their optical properties showing their high optical quality: one can easily resolve the absorption band edge of semiconducting vdW materials and even the excitonic features present in some vdW materials with high exciton binding energy. We also measured the electrical resistivity for several vdW materials films on paper finding exceptionally low values, which are in some cases, orders of magnitude lower than those reported for analogous films produced by inkjet printing. We finally demonstrate the fabrication of field-effect devices with vdW materials on paper using the paper substrate as an ionic gate.","Electrical properties; Optical properties; Paper-based electronics; Van der Waals materials","en","journal article","","","","","","","","","","","QN/Steeneken Lab","","",""
"uuid:b0e1dbc6-9bcc-4db7-94cc-c90be7d0b850","http://resolver.tudelft.nl/uuid:b0e1dbc6-9bcc-4db7-94cc-c90be7d0b850","The hydro-mechanical interaction in novel polyurethane-bound pervious pavement by considering the saturation states in unbound granular base course","Lu, Guoyang (The Hong Kong Polytechnic University; Rheinisch-Westfälische Technische Hochschule); Wang, H. (TU Delft Pavement Engineering); Zhang, Yuqing (Aston University); Liu, Pengfei (Rheinisch-Westfälische Technische Hochschule); Wang, Dawei (Rheinisch-Westfälische Technische Hochschule; Harbin Institute of Technology); Oeser, Markus (Rheinisch-Westfälische Technische Hochschule); Grabe, Jürgen (Hamburg University of Technology)","","2021","The pore-water pressure generated by intermittent dynamic vehicle loading under various saturation states is recognized as a critical factor influencing the behaviour of permeable pavement structures, especially the behaviour of UGB layer. However, the underlying mechanisms of hydro-mechanical interaction in the UGB layer and the influence on the pavement structure are still unclear. This study aims to characterize the changes in dynamic response in permeable pavement structures under various saturation conditions by considering the hydro-mechanical interaction within the UGB layer. To achieve this objective, a full-scale test track with a PUPM wearing course was constructed. Pressures and water distribution were characterized by embedded sensors within different layers of the test track when subjected to the accelerating pavement test. Based on the coupled SAME model, the water distribution and the dynamic response of UGB in the rainfall events were both characterised and solved by FEM. The results predicted by the proposed SAME model correspond to the field measurements, and the influence of the water content on the resilient modulus distribution within the UGB layer was then estimated. Based on the predictions for the stress state of the UGB layer, the sensitivity analysis was also proposed.","hydro-mechanical interaction; matric suction; polyurethane bound pervious material (PUPM); unsaturated flow; Water content","en","journal article","","","","","","Accepted Author Manuscript","","2022-05-12","","","Pavement Engineering","","",""
"uuid:e9c62634-5a29-4155-8f21-5abfc7f7ce28","http://resolver.tudelft.nl/uuid:e9c62634-5a29-4155-8f21-5abfc7f7ce28","Effects of Sediment-Induced Density Gradients on the Estuarine Turbidity Maximum in the Yangtze Estuary","Zhu, C. (TU Delft Coastal Engineering; East China Normal University); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; East China Normal University; Deltares); Guo, Leicheng (East China Normal University); Lin, J. (TU Delft Coastal Engineering; East China Normal University); He, Qing (East China Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; East China Normal University; Deltares)","","2021","An estuarine turbidity maximum (ETM) is a region of elevated suspended sediment concentration (SSC) resulting from residual transport mechanisms driven by river flow, tides, and salinity-induced density gradients (SalDG). However, in energetic and highly turbid environments such as the Yangtze Estuary, SedDG may also substantially contribute to the formation and maintenance of the ETM. Since this mechanism is relatively poorly understood, we develop a three-dimensional model to explore the effect of SedDG on tidal dynamics and sediment transport. By running sensitivity simulations considering SalDG and/or SedDG, we conclude that the longitudinal SedDG leads to degeneration and landward movement of the ETM. Moreover, two effects of the vertical SedDG are identified to be responsible for sediment trapping: One by enhancing the vertical sediment concentration gradients, and another by additionally affecting hydrodynamics including the water levels, velocities and salinities. The longitudinal and vertical SedDG leads to seasonal and spring-neap variations of upstream migration of the salt wedge: Vertical SedDG is more pronounced at neap tides in the wet season due to stronger stratification effects, whereas longitudinal SedDG is more pronounced at intermediate tides in the dry season due to weaker mixing and limited deposition. These findings imply that the SedDG contributes substantially to channel siltation and salt intrusion in highly turbid systems, and need to be accounted for when numerically modeling such phenomena.","salt intrusion; sediment trapping; sediment-induced density gradient; turbidity maximum","en","journal article","","","","","","","","2021-10-30","","","Coastal Engineering","","",""
"uuid:f09af991-0b93-4119-b5b8-fd538c7f2120","http://resolver.tudelft.nl/uuid:f09af991-0b93-4119-b5b8-fd538c7f2120","Two-channel system dynamics of the outer weser estuary—a modeling study","Gundlach, Jannek (Leibniz Universität); Zorndt, Anna (Federal Waterways Engineering and Research Institute (BAW)); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2021","In this paper, we unravel the mechanisms responsible for the development of the two-channel system in the Outer Weser Estuary. A process-based morphodynamic model is built based on a flat-bed approach using simplified boundary conditions and accelerated morphological develop-ment. The results are analyzed in two steps: first, by checking for morphodynamic equilibrium in the simulations and second, by applying a newly developed method that interprets simulations based on categorization of the two-channel system and cross-sectional correlation analysis. All simulations reach a morphodynamic equilibrium and develop two channels that vary considerably over time and between the simulations. Variations can be found in the location and depth of the two channels, the development of the dominant channel over time and the alteration in the dominance pattern. The conclusions are that the development of the two-channel system is mainly caused by the tides and the basin geometry. Furthermore, it is shown that the alternation pattern and period are dependent on the dominance of the tides compared to the influence of river discharge.","Delft3D; Long-term; Morphodynamics; Two-channel","en","journal article","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:ab6bccc6-d8ba-4a3c-99d0-fe7a156c53da","http://resolver.tudelft.nl/uuid:ab6bccc6-d8ba-4a3c-99d0-fe7a156c53da","A historical review of sediment export–import shift in the North Branch of Changjiang Estuary","Guo, Leicheng (East China Normal University); Xie, Weiming (East China Normal University); Xu, Fan (East China Normal University); Wang, Xianye (East China Normal University); Zhu, C. (TU Delft Coastal Engineering; East China Normal University); Meng, Yi (East China Normal University); Zhang, Weiguo (East China Normal University); He, Qing (East China Normal University)","","2021","Net sediment transport is predominantly seaward in fluvial-dominated estuaries worldwide. However, a distributary branch in the Changjiang Estuary, the North Branch, undergoes net landward sediment transport, which leads to severe channel aggradation. Its controlling mechanism and the role of human activities remain insufficiently understood, although such knowledge is necessary for better management and restoration opportunities. In this study we revisit the centennial hydro-morphodynamic evolution of the North Branch based on historical maps, field data, and satellite images and provide a synthesis of the regime change from ebb to flood dominance. The North Branch was once a major river and ebb-dominant distributary channel. Within which alternative meandering channels and sand bars developed. Deposition of river-borne sediment leads to infilling of the branch, while tidal flat embankment reduces the bankfull width and modifies the channel configuration, resulting in a profound decline in the sub-tidal flow partition rate. The North Branch then becomes tide-dominant with an occurrence of tidal bores and elongated sand ridges. Once tidal dominance is established, extensive tidal flat reclamation enhances the funnel-shaped planform, amplifying the incoming tides and initiating a positive feedback process that links tidal flat loss, sediment import, and channel aggradation. Overall, the shift in branch dominance is a combined result of a natural southeastward realignment of the deltaic distributary channels and extensive reclamation. One management option to mitigate channel aggradation is to stop the aggressive reclamation and allow tidal flats to build up, which might reduce the sediment import and eventually lead to a morphodynamic equilibrium in the longer term. Understanding the impact of tidal flat reclamation is informative for the management of similar tidal systems under strong human interference.","Changjiang; flood dominance; morphodynamics; reclamation; regime shift","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-07-29","","","Coastal Engineering","","",""
"uuid:416936bf-9906-4cdd-b29d-732e9cf5bc9a","http://resolver.tudelft.nl/uuid:416936bf-9906-4cdd-b29d-732e9cf5bc9a","Towards limiting potential domino effects from single flammable substance release in chemical complexes by risk-based shut down of critical nearby process units","Sun, Hao (China University of Petroleum (East China)); Wang, Haiqing (China University of Petroleum (East China)); Yang, M. (TU Delft Safety and Security Science); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Universiteit Antwerpen; Katholieke Universiteit Leuven)","","2021","The explosion load is a significant escalation factor possibly influencing the potential occurrence of domino accidents in chemical plants. It is not economical to install explosion isolation systems (e.g., extinguishing barrier) for all equipment or process units across a chemical plant. Although shutting down all equipment or process unit can prevent an explosion, it may also cause further economic losses. To prevent domino accidents, the process unit that needs to be shut down accurately should be selected, and the normal operation of other units needs to be ensured. A method to select the process unit to be isolated based on the Dimensioning Accidental Load (DAL) is proposed. By calculating the occurrence probability and consequences of the accident scenarios, the DAL of the surrounding units is determined. DAL is used as the impact intensity of the accident unit on the surrounding units. The probit model is used to calculate the damage probability of surrounding units. The case analysis results show that the method of selecting the process unit to be isolated based on DAL quantifies the impact intensity of the exploded unit on surrounding units from probability and consequence. Under the premise of meeting the acceptable risk criteria, the method can determine which units should be shut down and which units can operate normally when a release accident occurs. While preventing domino accidents, economic losses caused by the shutdown of all process units are reduced and a theoretical basis for accident prevention and safe operation of the plant is provided.","Dimensioning accident load; Domino accident; Safety; Vapor cloud explosion","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-08-23","","","Safety and Security Science","","",""
"uuid:ccc05f44-906d-4b83-9bce-82ae589b1012","http://resolver.tudelft.nl/uuid:ccc05f44-906d-4b83-9bce-82ae589b1012","Temporal gravity model for important node identification in temporal networks","Bi, Jialin (Shandong University); Jin, Ji (Shandong University); Qu, Cunquan (Shandong University); Zhan, X. (TU Delft Intelligent Systems; TU Delft Multimedia Computing); Wang, Guanghui (Shandong University); Yan, Guiying (Chinese Academy of Sciences; University of Chinese Academy of Sciences)","","2021","Identifying important nodes in networks is essential to analysing their structure and understanding their dynamical processes. In addition, myriad real systems are time-varying and can be represented as temporal networks. Motivated by classic gravity in physics, we propose a temporal gravity model to identify important nodes in temporal networks. In gravity, the attraction between two objects depends on their masses and distance. For the temporal network, we treat basic node properties (e.g., static and temporal properties) as the mass and temporal characteristics (i.e., fastest arrival distance and temporal shortest distance) as the distance. Experimental results on 10 real datasets show that the temporal gravity model outperforms baseline methods in quantifying the structural influence of nodes. When using the temporal shortest distance as the distance between two nodes, the proposed model is more robust and more accurately determines the node spreading influence than baseline methods. Furthermore, when using the temporal information to quantify the mass of each node, we found that a novel robust metric can be used to accurately determine the node influence regarding both network structure and information spreading.","Centrality; Important node; Temporal gravity model; Temporal networks","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-10-31","","Intelligent Systems","Multimedia Computing","","",""
"uuid:a1963b16-ade9-44ff-8be3-fb97f9ef9199","http://resolver.tudelft.nl/uuid:a1963b16-ade9-44ff-8be3-fb97f9ef9199","Performance evaluation of surrogate measures of safety with naturalistic driving data","Lu, Chang (Tongji University); He, X. (TU Delft Intelligent Vehicles); van Lint, J.W.C. (TU Delft Transport and Planning); Tu, Huizhao (Tongji University); Happee, R. (TU Delft Intelligent Vehicles); Wang, M. (TU Delft Transport and Planning)","","2021","Surrogate measures of safety (SMoS) play an important role in detecting traffic conflicts and in traffic safety assessment. However, the underlying assumptions of SMoS are different and a certain SMoS may be adequate/inadequate for different applications. A comprehensive approach to evaluate the validity and applicability of SMoS is lacking in the literature. This study proposes such a framework that supports evaluating SMoS in multiple dimensions. We apply the framework to gain insights into the characteristics of six widely-used SMoS for longitudinal maneuvers, i.e., Time to Collision (TTC), single-step Probabilistic Driving Risk Field (S-PDRF), Deceleration Rate to Avoid a Crash (DRAC), Potential Index for Collision with Urgent Deceleration (PICUD), Proactive Fuzzy Surrogate Safety Metric (PFS), and the Critical Fuzzy Surrogate Safety Metric (CFS). To ensure comparability, all measures are calibrated with the same risk detection criterion. Four performance indicators, i.e., Prediction Accuracy, Timeliness, Robustness, and Efficiency are computed for all six SMoS and validated using naturalistic driving data. The strengths and weaknesses of all six measures are compared and analyzed elaborately. A key result is that not a single SMoS performs well in all performance dimensions. S-PDRF performs best in terms of Robustness but consumes the most time for computation. TTC is the most efficient but performs poorly in terms of Timeliness and Robustness. The proposed evaluation approach and the derived insights can support SMoS selection in active vehicle safety system design and traffic safety assessment.","Empirical analysis; Naturalistic driving data; Performance evaluation; Surrogate measure of safety","en","journal article","","","","","","","","","","","Intelligent Vehicles","","",""
"uuid:1f7d4796-c759-4b39-8894-c823a313bcf1","http://resolver.tudelft.nl/uuid:1f7d4796-c759-4b39-8894-c823a313bcf1","Transformation towards a carbon-neutral residential community with hydrogen economy and advanced energy management strategies","He, Yingdong (University of California; Hunan University); Zhou, Yuekuan (The Hong Kong University of Science and Technology); Yuan, Jing (University of California); Liu, Zhengxuan (TU Delft Housing Quality and Process Innovation; Hunan University); Wang, Zhe (Lawrence Berkeley National Laboratory); Zhang, Guoqiang (Hunan University)","","2021","Cleaner power production, distributed renewable generation, building-vehicle integration, hydrogen storage and associated infrastructures are promising for transformation towards a carbon–neutral community, whereas the academia provides limited information through integrated solutions, like intermittent renewable integration, hydrogen sharing network, smart operation on electrolyzer and fuel cell, seasonal hydrogen storage and advanced heat recovery. This study proposes a hybrid electricity-hydrogen sharing system in California, United States, with synergistic electric, thermal and hydrogen interactions, including low-rise houses, rooftop photovoltaic panels, hydrogen vehicles, a hydrogen station, micro and utility power grid and hydrogen pipelines. Advanced energy management strategies were proposed to enhance energy flexibility and grid stability. Besides, simulation-based optimizations on smart power flows of vehicle-to-grid interaction and electrolyzer are conducted for further seasonal grid stability and annual cost saving. The obtained results indicate that, the green renewable-to-hydrogen can effectively reduce reliance on pipelines delivered hydrogen, and the hydrogen station is effective to address security concerns of high-pressure hydrogen and improve participators’ acceptance. Microgrid peer-to-peer sharing can improve hydrogen system efficiency under idling modes. Furthermore, the integrated system can reduce the annual net hydrogen consumption in transportation from 127.0 to 1.2 kg/vehicle. The smart operation (minimum input power of electrolyzer and fuel cell at 65 and 80 kW) can reduce the maximum mean hourly grid power to 78.2 kW by 24.2% and the annual energy cost to 1228.5 $/household by 38.9%. The proposed district hydrogen-based community framework can provide cutting-edge techno-economic guidelines for carbon-neutral transition with district peer-to-peer energy sharing, zero-energy buildings, hydrogen-based transportations together with smart strategies for high energy flexibility.","Distributed hydrogen infrastructure; Distributed renewable energy sharing; Flexible energy management strategy; Hydrogen energy storage and economy; Solar energy","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-04-09","","","Housing Quality and Process Innovation","","",""
"uuid:a688376d-2c9b-4ed6-bc39-9bc3f155d01d","http://resolver.tudelft.nl/uuid:a688376d-2c9b-4ed6-bc39-9bc3f155d01d","Light scattering by gold nanoparticles cured in optical adhesive at optical fibre interfaces","Wang, X. (TU Delft Structural Integrity & Composites); Benedictus, R. (TU Delft Structural Integrity & Composites); Groves, R.M. (TU Delft Structural Integrity & Composites)","Lehmann, Peter (editor); Osten, Wolfgang (editor); Goncalves, Armando Albertazzi (editor)","2021","This study forms a part of the research in using nanoparticles (NPs) to increase the intensity of light scattering signal in the optical fibres. Increasing the intensity of the backscattered light signal in the optical fibres shows the potential to increase the signal-to-noise ratio in order to improve the sensitivity of the backscatter reflectometry. Doping NPs into the optical fibres can greatly increase the scattered light. However, it is not easy to manufacture NP-doped optical fibres to test different designs. To overcome this problem, in our former work we used the method of dropping refractive index matching liquid containing gold NPs at the optical fibres end tips to investigate the intensity change of the scattered light from the interfaces. In this paper, some new initial experimental results for the scattered light between the optical fibre end tips are shown. Gold NPs have been mixed into the optical adhesive (Norland) and is then dropped and cured at the optical fibre end tips. A backscatter reflectometer (LUNA ODiSI-B) was used in the experiment to measure the intensity of scattered light distribution between the optical fibre end tips. We investigated 4 cases of light scattering between the optical fibre end tips: (i) the backscattered light intensity distribution in the case of the air gap between the optical fibre end tips; (ii) the backscattered light intensity distribution with optical adhesive between the optical fibre end tips; (iii) the backscattered light intensity distribution with optical adhesive containing gold NPs (gold nanopowder (<100 nm), Sigma Aldrich) between the optical fibre end tips before curing process and (iv) the backscattered light intensity distribution with optical adhesive containing gold NPs between the optical fibre end tips after the curing process. Our initial findings are that the scattered light by gold NPs at the optical fibre interfaces can be detected by the backscatter reflectometer. By obtaining the differential signal between the distributed light scattering by cured optical adhesive containing gold NPs and only optical adhesive between the optical fibre end tips, the light scattered by the gold NPs has be determined.","Curing process; Gold nanoparticle; Light scattering; Optical adhesive","en","conference paper","SPIE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-04-12","","","Structural Integrity & Composites","","",""
"uuid:c51625d4-bbb7-44e1-b62b-d83c8139afbf","http://resolver.tudelft.nl/uuid:c51625d4-bbb7-44e1-b62b-d83c8139afbf","The impact of wind-waves and sea level rise on the morphodynamics of a sandy estuarine shoal","Zheng, J. (Deltares; Student TU Delft); Elmilady, H.M.S.M.A. (TU Delft Coastal Engineering; Deltares; IHE Delft Institute for Water Education); Röbke, B. R. (Deltares); Taal, M. (Deltares); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); de Vet, P.L.M. (TU Delft Coastal Engineering; Deltares); van der Wegen, M. (Deltares; IHE Delft Institute for Water Education)","","2021","Intertidal shoals are pronounced morphological features found in many estuaries worldwide. Apart from maintaining an ecologically unique intertidal environment, shoals also protect adjacent dyke systems by attenuating waves. The fate of sandy shoals under anticipated sea level rise (SLR) scenarios is underexplored. The current research investigates the long-term morphodynamic evolution of estuarine sandy shoals under forcing by short fetch, locally generated wind-waves, tides, and SLR by means of a numerical, process-based model (Delft3D). The focus lies on a sheltered shoal complex in the Western Scheldt, the Netherlands. Starting from the initial, 1963 bathymetry, we model 50-year morphodynamic development with schematized wind-wave forcing. We analyze in detail the impact of locally generated wind-waves on shoal formation. Finally, we impose regional SLR of 1.10 m and 1.95 m for 100 years. Model results show that, on the spatial scale of intertidal flats, small, locally generated wind-waves lower and widen the shoals while the adjacent channels deepen. However, on the estuarine system scale, wind-waves do not lead to fundamentally different channel–shoal patterns and morphodynamic evolution trends. This suggests that channel–shoal formation is mainly due to tide residual sediment transports, with wind-waves playing a secondary role. SLR leads to a notable intertidal area loss, despite a continuous heightening of the shoals, implying that morphodynamic adaptation lags behind SLR. The inclusion of wind-waves does not fundamentally change the reaction of the estuarine shoal to SLR. Future research may focus on exploring the impact of including multiple sediment classes.","Estuarine morphodynamics; Intertidal flat; Morphodynamic modeling; Sandy shoal evolution; Sea level rise","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:db54be26-4603-47c6-8966-5743c9e9eb1e","http://resolver.tudelft.nl/uuid:db54be26-4603-47c6-8966-5743c9e9eb1e","Exploration of Decadal Tidal Evolution in Response to Morphological and Sedimentary Changes in the Yangtze Estuary","Zhu, C. (TU Delft Coastal Engineering; East China Normal University); Guo, Leicheng (East China Normal University); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; East China Normal University; Deltares); Wang, Zhengbing (TU Delft Coastal Engineering; East China Normal University; Deltares); He, Qing (East China Normal University)","","2021","Estuarine tidal dynamics are influenced by changes in morphology and friction. In this work, we quantified changes in tidal damping in the Yangtze Estuary and explored the impact of morphology and friction using a numerical model. In-depth analyses of tidal data reveal a strong reduction in tidal damping from 1990 to 2010, followed by a slightly enhanced damping from 2010 to 2020 in the South Branch. The reduced tidal damping in the South Branch from 1990 to 2010 is controlled by sediment decline which induces an increase in water depth (erosion), thereby strongly amplifying tides. However, the effective bottom roughness (Manning coefficient) is increased by 60%, which is probably related to the (Formula presented.) 80% decrease in the suspended sediment concentration (SSC). Such an effect may enhance tidal damping, which counteracts the contribution of water depth increase on amplifying tides by (Formula presented.) 75%. From 2010 to 2020, the tides in the South Branch became more damped, suggesting a dominance of the decrease in SSC over the morphological changes. In the mouth zone, tidal dissipation is enhanced from 1997 to 2010, which is mainly caused by an overall increase in effective bottom roughness. Local structures dominate the increase in effective bottom roughness; however, fluid mud formation may contribute to a decrease after 2010. Overall, we argue that estuarine morphological and sedimentary changes in response to riverine sediment decline and local engineering works control the tidal evolution in the Yangtze Estuary, which is important for evaluation of human activities and estuarine management.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-02-02","","","Coastal Engineering","","",""
"uuid:a80e59b6-fd3a-4516-8984-439f31145678","http://resolver.tudelft.nl/uuid:a80e59b6-fd3a-4516-8984-439f31145678","Is the tropical cyclone surge in Shanghai more sensitive to landfall location or intensity change?","Wang, Shuai (Imperial College London); Toumi, Ralf (Imperial College London); Ye, Qinghua (TU Delft Coastal Engineering; Deltares); Ke, Q. (TU Delft Hydraulic Structures and Flood Risk); Bricker, J.D. (TU Delft Hydraulic Structures and Flood Risk; University of Michigan); Tian, Zhan (Southern University of Science and Technology); Sun, Laixiang (University of Maryland; SOAS University of London)","","2021","It has been shown that the proportion of intense tropical cyclones (TCs) has been increasing together with a poleward migration of TC track. However, their relative importance to TC surge at landfall remains unknown. Here we examine the sensitivity of TC surge in Shanghai to landfall location and intensity with a new dynamical modelling framework. We find a surge sensitivity of 0.8 m (°N)−1 to landfall location, and 0.1 m (m s−1)−1 to wind speed in Shanghai during landfall. The landfall location and intensity are comparably important to surge variation. However, based on a plausible range of reported trends of TC poleward migration and intensity, the potential surge hazard due to poleward migration is estimated to be about three times larger than that by intensity change. The long-term surge risk in Shanghai is therefore substantially more sensitive to changes of TC track and landfall location than intensity. This may also be true elsewhere and in the future.","climate change; landfall; storm surge; tropical cyclone","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:9896e66a-2139-47f7-a497-a2a0069c121a","http://resolver.tudelft.nl/uuid:9896e66a-2139-47f7-a497-a2a0069c121a","Changjiang Delta in the Anthropocene: Multi-scale hydro-morphodynamics and management challenges","Guo, Leicheng (East China Normal University); Zhu, C. (TU Delft Coastal Engineering; East China Normal University); Xie, Weiming (East China Normal University); Xu, Fan (East China Normal University); Wu, Hui (East China Normal University); Wan, Yuanyang (Shanghai Estuarine and Coastal Research Center); Wang, Zhanghua (East China Normal University); Zhang, Weiguo (East China Normal University); Shen, Jian (Virginia Institute of Marine Science); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); He, Qing (East China Normal University)","","2021","The Changjiang Delta (CD) is one of well-studied large deltas of critical socio-economical and ecological importance regionally and global representativeness. Cumulated field data and numerical modeling has facilitated scientific understanding of its hydro-morphodynamics at multiple spatial and time scales, but the changing boundary forcing conditions and increasing anthropogenic influences pose management challenges requiring integrated knowledge. Here we provide a comprehensive synthesis of the multi-scale deltaic hydro-morphodynamics, discuss their relevance and management perspectives in a global context, and identify knowledge gaps for future study. The CD is classified as a river-tide mixed-energy, muddy and highly turbid, fluvio-deltaic composite system involving large-scale land-ocean interacted processes. Its hydro-morphodynamic evolution exhibits profound temporal variations at the fortnightly, seasonal, and inter-annual time scales, and strong spatial variability between tidal river and tidal estuary, and between different distributary channels. As the river-borne sediment has declined >70%, the deltaic morphodynamic adaptation lags behind sediment decline because sediment redistribution within the delta emerges to play a role in sustaining tidal flat accretion. However, the deltaic channels have become narrower, deepened and growingly constrained under cumulated human activities, e.g., extensive embankment and construction of jetties and groins, possibly initiating a decrease in morphodynamic activities and sediment trapping efficiency. Overall, the CD undergoes transitions from net sedimentation and naturally slow morphodynamic adaptation to erosion and human-driven radical adjustment. A shift in management priority from delta development to ecosystem conservation provides an opportunity for restoring the resilience to flooding and erosion hazards. The lessons and identified knowledge gaps inform study and management of worldwide estuaries and deltas undergoing intensified human interferences.","Changjiang; Delta; Human activities; Morphology; Sediment; Tide","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-05-05","","","Coastal Engineering","","",""
"uuid:025d26d9-fc7a-4b35-8f17-7ed5092691dc","http://resolver.tudelft.nl/uuid:025d26d9-fc7a-4b35-8f17-7ed5092691dc","High dielectric barium titanate porous scaffold for efficient Li metal cycling in anode-free cells","Wang, C. (TU Delft RST/Storage of Electrochemical Energy); Liu, M. (TU Delft Team Arjan Mol); Thijs, M.A. (TU Delft RID/TS/Technici Pool); Ooms, F.G.B. (TU Delft RST/Technici Pool); Ganapathy, S. (TU Delft RID/TS/Instrumenten groep); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2021","Li metal batteries are being intensively investigated as a means to achieve higher energy density when compared with standard Li-ion batteries. However, the formation of dendritic and mossy Li metal microstructures at the negative electrode during stripping/plating cycles causes electrolyte decomposition and the formation of electronically disconnected Li metal particles. Here we investigate the use of a Cu current collector coated with a high dielectric BaTiO3 porous scaffold to suppress the electrical field gradients that cause morphological inhomogeneities during Li metal stripping/plating. Applying operando solid-state nuclear magnetic resonance measurements, we demonstrate that the high dielectric BaTiO3 porous scaffold promotes dense Li deposition, improves the average plating/stripping efficiency and extends the cycling life of the cell compared to both bare Cu and to a low dielectric scaffold material (i.e., Al2O3). We report electrochemical tests in full anode-free coin cells using a LiNi0.8Co0.1Mn0.1O2-based positive electrode and a LiPF6-based electrolyte to demonstrate the cycling efficiency of the BaTiO3-coated Cu electrode.","OA-Fund TU Delft","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:a3bea884-2d49-4fe0-825d-4836fd6346c4","http://resolver.tudelft.nl/uuid:a3bea884-2d49-4fe0-825d-4836fd6346c4","An incremental clustering method for anomaly detection in flight data","Zhao, Weizun (City University of Hong Kong); Li, L. (TU Delft Air Transport & Operations; City University of Hong Kong); Alam, Sameer (Nanyang Technological University); Wang, Yanjun (Nanjing University of Aeronautics and Astronautics)","","2021","Safety is a top priority for civil aviation. Data mining in digital Flight Data Recorder (FDR) or Quick Access Recorder (QAR) data, commonly referred to as black box data on aircraft, has gained interest for proactive safety management. New anomaly detection methods, primarily clustering methods, have been developed to monitor pilot operations and detect any risks from such flight data. However, all existing anomaly detection methods are offline learning — the models are trained once using historical data and used for all future predictions. In practice, new flight data are accumulated continuously and analyzed every month at airlines. Clustering such dynamically growing data is challenging for an offline method because it is memory and time intensive to re-train the model every time new data come in. If the model is not re-trained, false alarms or missed detections may increase since the model cannot reflect changes in data patterns. To address this problem, we propose a novel incremental anomaly detection method based on Gaussian Mixture Model (GMM) to identify common patterns and detect outliers in flight operations from digital flight data. It is a probabilistic clustering model of flight operations that can incrementally update its clusters based on new data rather than to re-cluster all data from scratch. It trains an initial GMM model based on historical offline data. Then, it continuously adapts to new incoming data points via an expectation–maximization (EM) algorithm. To track changes in flight operation patterns, only model parameters need to be saved, not the raw flight data. The proposed method was tested on three sets of simulation data and two sets of real-world flight data. Compared with the traditional offline GMM method, the proposed method can generate similar clustering results with significantly reduced processing time (57 %–99 % time reduction in testing sets) and memory usage (91 %–95 % memory usage reduction in testing sets). Preliminary results indicate that the incremental learning scheme is effective in dealing with dynamically growing data in flight data analytics.","Anomaly detection; Flight data; Gaussian mixture model; Incremental clustering","en","journal article","","","","","","","","","","","Air Transport & Operations","","",""
"uuid:11274c68-da0b-4104-9d11-dc95c11b9595","http://resolver.tudelft.nl/uuid:11274c68-da0b-4104-9d11-dc95c11b9595","Solvent-Free Three-Dimensional Printing of Biodegradable Elastomers Using Liquid Macrophotoinitiators","Sandmeier, Matthias (ETH Zürich); Paunović, Nevena (ETH Zürich); Conti, Riccardo (ETH Zürich); Hofmann, Leopold (ETH Zürich); Wang, Jieping (ETH Zürich); Luo, Zhi (ETH Zürich); Masania, K. (TU Delft Aerospace Manufacturing Technologies; ETH Zürich); Wu, N. (TU Delft Team Bart De Schutter; Lab of Organic Chemistry; ETH Zürich); Kleger, Nicole (ETH Zürich)","","2021","Vat photopolymerization 3D printing provides new opportunities for the fabrication of tissue scaffolds and medical devices. However, for the manufacturing of biodegradable elastomers, it usually requires the use of organic solvents to dissolve the solid photoinitators and achieve low resin viscosity, making this process environmentally unfriendly and not optimal for biomedical applications. Here, we report solvent-free 3D printing of biodegradable elastomers by digital light processing with well-defined photoinitiator-polymer conjugates. Being in liquid state at room temperature, the macrophotoinitiators enabled high-quality 3D printing in the absence of any organic solvents that are usually used in digital light 3D printing. This allowed the systematic investigation of structure-property relationships of 3D-printed biodegradable elastomers without the interference from reactive diluents. The developed macrophotoinitiators were compatible with various photopolymers and could be applied for solvent-free fabrication of biodegradable shape-memory devices. This work offers new perspectives for the solvent-free additive manufacturing of bioresorbable medical implants and other functional devices.","","en","journal article","","","","","","","","","","","Aerospace Manufacturing Technologies","","",""
"uuid:505d445b-6f4b-4110-9f96-0f9c96f7109a","http://resolver.tudelft.nl/uuid:505d445b-6f4b-4110-9f96-0f9c96f7109a","Micro-scale Realization of Compliant Mechanisms: Manufacturing Processes and Constituent Materials—A Review","Wang, M. (TU Delft Mechatronic Systems Design; Jiangsu University); Ge, Daohan (Jiangsu University); Zhang, Liqiang (Jiangsu University); Herder, J.L. (TU Delft Precision and Microsystems Engineering; TU Delft Mechatronic Systems Design)","","2021","Compliant micromechanisms (CMMs) acquire mobility from the deflection of elastic members and have been proven to be robust by millions of silicon MEMS devices. However, the limited deflection of silicon impedes the realization of more sophisticated CMMs, which often require larger deflections. Recently, some novel manufacturing processes have emerged but are not well known by the community. In this paper, the realization of CMMs is reviewed, aiming to provide help to mechanical designers to quickly find the proper realization method for their CMM designs. To this end, the literature surveyed was classified and statistically analyzed, and representative processes were summarized individually to reflect the state of the art of CMM manufacturing. Furthermore, the features of each process were collected into tables to facilitate the reference of readers, and the guidelines for process selection were discussed. The review results indicate that, even though the silicon process remains dominant, great progress has been made in the development of polymer-related and composite-related processes, such as micromolding, SU-8 process, laser ablation, 3D printing, and the CNT frameworking. These processes result in constituent materials with a lower Young’s modulus and larger maximum allowable strain than silicon, and therefore allow larger deflection. The geometrical capabilities (e.g., aspect ratio) of the realization methods should also be considered, because different types of CMMs have different requirements. We conclude that the SU-8 process, 3D printing, and carbon nanotube frameworking will play more important roles in the future owing to their excellent comprehensive capabilities.","Compliant micromechanism; Constituent material; Manufacturing process","en","review","","","","","","","","","","Precision and Microsystems Engineering","Mechatronic Systems Design","","",""
"uuid:c731b535-5ac4-42e1-9542-67c73678f9c2","http://resolver.tudelft.nl/uuid:c731b535-5ac4-42e1-9542-67c73678f9c2","Study on the aging resistance of polyurethane precursor modified bitumen and its mechanism","Zhang, Liang (Heilongjiang Highway Construction Center); Li, Pengfei (Highway Engineering Cost Station of Heilongjiang Province); Hu, Guanfeng (Heilongjiang Longjian Road bridge 5th Engineering Co); Zhang, Sufeng (Heilongjiang Highway Construction Center); Hong, Bin (Harbin Institute of Technology); Wang, H. (TU Delft Pavement Engineering); Wang, Dawei (Harbin Institute of Technology; Rheinisch-Westfälische Technische Hochschule); Oeser, Markus (Rheinisch-Westfälische Technische Hochschule)","","2021","As an environmentally friendly alternative for the production of high-performance modified asphalt by chemical reactions, a liquid-state polyurethane-precursor-based reactive modifier (PRM) was developed and employed in the asphalt modification. In contrast to the traditional solid bitumen modifier, for example, rubber and thermoplastic elastomers, the PRM as a liquid modifier has more significant advantages in reducing energy consumption and improving asphalt performance, which has attracted widespread attention. However, the aging resistance and its mechanism are not clear. In view of this, the aging performance of two PRM-modified bitumen (PRM-70 and PRM-90), under the short-term thermo-oxidative aging, long-term thermo-oxidative aging, and ultraviolet (UV) aging conditions, was investigated through chemical and mechanical methods. The results show that the PRM-90 is more susceptible to the thermos-oxidative aging and UV aging. The use of low-penetration-grade bitumen and ensuring an adequate reaction are beneficial to enhance the aging resistance of PRM-modified bitumen. The impact of aging on high-temperature performance of PRM-modified bitumen is great, followed by the low-temperature performance and the anti-fatigue performance. The mechanic-relevant rheological aging index (RAI) and fracture energy index (FEI) are recommended to evaluate aging properties for PRM-modified bitumen. This study not only provides support for further research on the relationship between the aging properties and mechanical performance of PRM-modified bitumen, but also provides a reference for conducting mechanism analysis.","Aging resistance; Modified bitumen; Polyurethane precursor; Thermal-oxidation aging; Ultraviolet aging","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:ca60c2cf-a140-4b54-bfa2-582120418bc6","http://resolver.tudelft.nl/uuid:ca60c2cf-a140-4b54-bfa2-582120418bc6","CO2 migration and distribution in multiscale-heterogeneous deep saline aquifers","Ren, Jie (Hohai University); Wang, Yuan (Hohai University); Feng, Di (Hohai University); Gong, J. (TU Delft Reservoir Engineering; Hohai University)","","2021","Large volumes of carbon dioxide (CO2) captured from carbon emission source can be stored in deep saline aquifers as a mean of mitigating climate change. The deep saline aquifers are naturally heterogeneous at multiple scales. It is important to generate representative multiscale heterogeneous fields of various hydrogeologic properties and understand storage safety by studying CO2 migration and distribution in such fields. In this work, a new multiscale heterogeneous model with partly fine multi-facies heterogeneous domain is proposed. A method based on transition probability theory is referred to establish a multi-facies model. A new multiscale heterogeneous model with partly fine multi-facies heterogeneous domain is built up according to the categorized permeability data obtained from the Geological Carbon Storage Frio site in USA. TOUGH2/ECO2N is applied to simulate CO2 migration and distribution in such a multiscale heterogeneous model. The CO2 plume shows obvious viscous fingering and non-uniform migration both in layered and vertical directions, implying vertical and horizontal heterogeneity which cannot be represented by a single-scale model or simulated with the assumption of homogeneous formation. The profile of CO2 migration shown in the numerical simulation at a time of 10 days is in a good accordance with the seismic data of Frio situ in qualitative and quantitative aspects.","CO migration and distribution; Heterogeneous aquifers; Multi-facies; Multi-scale; Transition probability; Viscous fingering flow","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:2484df02-c994-46e3-9ecc-45a43cedc07f","http://resolver.tudelft.nl/uuid:2484df02-c994-46e3-9ecc-45a43cedc07f","Numerical investigation of the flow field and mass transfer characteristics in a jet slurry pump","Qian, Yi’Nan (Wuhan University); Wang, Yuanshun (Shanghai Jiao Tong University); Fang, Zhenlong (Wuhan University of Technology); Chen, X. (TU Delft Offshore and Dredging Engineering); Miedema, S.A. (TU Delft Offshore and Dredging Engineering)","","2021","A jet pump is used to transport a variety of working media and is especially suitable for dredged soil transporting. In this study, a three-dimensional numerical study of a jet pump that is used for slurry delivery was carried out. The characteristics of the internal flow field of the mixing chamber with different working parameters were comprehensively analyzed. The results indicate that the pressure of the axial line decreases with increasing flow ratio (ratio of suction flux and inlet flux) while the pressure of the injected slurry shows a downward trend. With the increase in the flow ratio, the pressure ratio (difference between inlet pressure and suction pressure divided by the difference between exit pressure and suction pressure) falls off while the efficiency presents a parabolic distribution. The pressure ratio can be promoted by properly increasing the length of the mixing chamber so that the available efficiency is broadened. When the mixing chamber length is L = 2.5Dn~4.0Dn (Dn is nozzle outlet diameter), the highly efficient area is wide; in particular, when L = 3.5Dn, the jet slurry pump with the highest efficiency of 27.6% has the best performance.","CFD; Efficiency; Flow ratio; Jet pump; Slurry","en","journal article","","","","","","","","","","","Offshore and Dredging Engineering","","",""
"uuid:16744ca5-a6d5-4af5-b189-76ab23754240","http://resolver.tudelft.nl/uuid:16744ca5-a6d5-4af5-b189-76ab23754240","Mobile services use and citizen satisfaction in government: integrating social benefits and uses and gratifications theory","Wang, Changlin (Henan University of Economics and Law); Teo, Thompson S.H. (National University of Singapore); Dwivedi, Yogesh (Swansea University); Janssen, M.F.W.H.A. (TU Delft Information and Communication Technology)","","2021","Purpose: Citizen satisfaction with the government is a longstanding and continuous concern in public administration. However, past research did not investigate the effect on satisfaction with the government in the context of mobile government (m-government). The purpose of this paper is to evaluate how the social benefits of citizens using m-government affect their satisfaction with the government. Design/methodology/approach: Grounded in the uses and gratifications theory (UGT), the authors suggest that the satisfaction in m-government should be constructed in terms of the satisfaction with m-government and the satisfaction with the government. The research model of citizen satisfaction in the context of m-government is tested through partial least squares (PLS) (SmartPLS 2.0) based on data collected from a survey study in China. Findings: The results indicate that the three important social benefits, e.g. convenience, transparency and participation, are positively associated with process gratification, whereas only convenience is positively associated with content gratification. The results suggest that both process gratification and content gratification are positively associated with citizen satisfaction with the government. Furthermore, the research suggests that process and content gratification have a mediating role, whereas compatibility has a moderating role. Practical implications: This research provides insights to practitioners on how to facilitate citizen satisfaction by increasing citizens’ social benefits and improving process and content gratification. Originality/value: This study contributes to the literature by offering a framework for analyzing the impact of citizens’ use of m-government on their satisfaction with the government. The work also contributes to UGT by categorizing user gratifications into process gratifications, content gratifications and citizen satisfaction with the government.","Citizen satisfaction; Compatibility; E-government; Mobile government; Participation; Transparency; Uses and gratifications theory","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-11-14","","","Information and Communication Technology","","",""
"uuid:03087d00-59e0-42b2-8ff3-32047feb5c89","http://resolver.tudelft.nl/uuid:03087d00-59e0-42b2-8ff3-32047feb5c89","Thermal aging behaviors of the waste tire rubber used in bitumen modification","Wang, H. (TU Delft Pavement Engineering; The Hong Kong Polytechnic University); Liu, X. (TU Delft Pavement Engineering); Varveri, Aikaterini (TU Delft Pavement Engineering); Zhang, H. (TU Delft Materials and Environment; Shandong University); Erkens, S. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Khalifa University of Science and Technology); Leng, Zhen (The Hong Kong Polytechnic University)","","2021","Considering the application scenarios of rubber granules from waste tires in the bitumen modification process (wet or dry process), both aerobic and anaerobic aging of rubber may occur. The current study aims to investigate the thermal aging behavior of waste tire rubber samples using nanoindentation and environment scanning electron microscopy (ESEM) tests. Both aerobic and anaerobic aging tests with different durations were conducted on rubber samples. The complex moduli of aged rubber samples were measured by nanoindentation tests. The surface morphology and elemental composition of aged samples were obtained by ESEM tests together with the energy dispersive X-ray analysis. Results have shown that for both aerobic and anaerobic aging, the equilibrium modulus derived from the complex modulus curve first increases and then decreases with aging time. However, the time needed for the aerobically aged sample to reach the maximum equilibrium modulus is shorter than the anaerobic case. Aging results in crack propagation and an increase of sulfur content on the rubber surface until it reaches the peak. The degree of crosslinking reflected by sulfur content for anaerobic aging is higher than aerobic aging. The morphological change and elemental change of rubber correlate well with the change of mechanical properties. The aging of rubber from the waste truck tire at 180°C can generally be separated into two stages: crosslinking dominant stage and chain scission dominant stage.","EDX; ESEM; nanoindentation; thermal aging; viscoelasticity; Waste tire rubber","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:0674b38c-2a47-4b38-9895-97af8ae7d0d8","http://resolver.tudelft.nl/uuid:0674b38c-2a47-4b38-9895-97af8ae7d0d8","Numerical simulation on reflective cracking behavior of asphalt pavement","Wang, Houzhi (Southeast University); Wu, You (Southeast University); Yang, Jun (Southeast University); Wang, H. (TU Delft Pavement Engineering)","","2021","Cracks are one of the main problems that plague road workers. A correct understanding of the internal crack propagation mechanism of asphalt pavement will help road workers evaluate the road’s working status more comprehensively and make more reasonable decisions in design, construction, and maintenance work. This paper established a three-dimensional asphalt pavement layered model using the software ABAQUS and fracture mechanics theory and the extended finite element method were used to explore the mechanical response of the pavement base layer’s preset reflective cracks. This paper investigated the influence of the modulus of each layer, vehicle load on the principal stress, shear stress, J-integral, and two stress intensity factors (K1, K2) during the pre-determined crack propagation process of the pavement base layer, and the entropy method was used to analyze the above-mentioned mechanical response. The results show that the main factor affecting the propagation of reflective cracks on asphalt pavements is the modulus of the bottom surface layer. However, from a modeling perspective, the effect of increasing load on crack growth is obvious. Therefore, in terms of technical feasibility, the prevention of reflective cracks should still be achieved by controlling the driving load and prohibiting overloading.","Extended finite element method; J-integral; Numerical analysis; Reflection crack; Stress intensity factors","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:e5fb4316-5b3f-40d0-89a5-4d6690bfed5d","http://resolver.tudelft.nl/uuid:e5fb4316-5b3f-40d0-89a5-4d6690bfed5d","Frequency division multiplexing readout of 60 low-noise transition-edge sensor bolometers","Wang, Q. (SRON Netherlands Institute for Space Research; Rijksuniversiteit Groningen); Khosropanah, P. (SRON Netherlands Institute for Space Research); Van Der Kuur, J. (SRON Netherlands Institute for Space Research); de Lange, G. (SRON Netherlands Institute for Space Research); Audley, M. D. (SRON Netherlands Institute for Space Research); Aminaei, A. (SRON Netherlands Institute for Space Research); Ridder, M.L. (SRON Netherlands Institute for Space Research); Van Der Linden, A. J. (SRON Netherlands Institute for Space Research); Bruijn, M. P. (SRON Netherlands Institute for Space Research); Gao, J.R. (TU Delft ImPhys/Optics; SRON Netherlands Institute for Space Research)","","2021","We demonstrate multiplexing readout of 60 transition edge sensor (TES) bolometers operating at 90 mK using a frequency division multiplexing readout chain with bias frequencies ranging from 1 to 3.5 MHz and with a typical frequency spacing of 32 kHz. The readout chain starts with a two-stage SQUID amplifier and has a noise level of 9.5 pA/ Hz. We compare current-voltage curves and noise spectra of TESs measured in a single-pixel mode and in a multiplexing mode. We also map the noise equivalent power (NEP) and the saturation power of the bolometers in both modes, where there are 43 pixels that do not show more than 10% difference in NEP and 5% in saturation power when measured in single pixel and multiplex modes. We have read out a TES with an NEP of 0.45 aW/ Hz in the multiplexing-mode, which demonstrates the capability of reading out ultra-low noise TES bolometer arrays for space applications.","","en","journal article","","","","","","Accepted Author Manuscript","","","","","ImPhys/Optics","","",""
"uuid:d268f674-5f0c-4635-97dc-02274472e049","http://resolver.tudelft.nl/uuid:d268f674-5f0c-4635-97dc-02274472e049","Multi-scale experimental testing on variable stiffness and damping components for semi-active structural control","Wang, Qinyu (Eindhoven University of Technology); Senatore, Gennaro (Swiss Federal Institute of Technology); Jansen, K.M.B. (TU Delft Emerging Materials; TU Delft Sustainable Design Engineering); Habraken, Arjan (Eindhoven University of Technology); Teuffel, Patrick","","2021","This paper presents experimental testing of a new semi-active vibration control device comprising a shape memory polymer (SMP) core that is reinforced by an SMP-aramid composite skin. This control device works as a load-transfer component that can be integrated into truss and frame structures in the form of a joint. At the material level, thermal actuation from ambient (25 °C) to transition temperature (65 °C) causes a significant 40-fold increase in damping due to viscoelastic effects. At the component level, uniaxial tensile and four-point bending tests have shown that tensile strength depends primarily on the bond strength between the reinforcement skin and the structural element while flexural strength depends on the strength of the reinforcement skin fibers. Through cyclic testing, it has been observed that material viscoelasticity is beneficial to ductility and energy dissipation. When the joint core is actuated to the SMP transition temperature, axial and flexural stiffness decrease by up to 50% and 90%, respectively. The property change at material and component levels enable tuning the frequency and damping ratio at the structure level, which has been successfully employed to mitigate the dynamic response of a 1/10 scale three-story prototype frame under resonance and earthquake loadings.","Adaptive structures; Multiscale experimental testing; Semi-active vibration control; Structural joint; Variable stiffness and damping; Viscoelastic material","en","journal article","","","","","","","","","","Sustainable Design Engineering","Emerging Materials","","",""
"uuid:44a28492-a2b5-4021-a481-ae3400ba43ed","http://resolver.tudelft.nl/uuid:44a28492-a2b5-4021-a481-ae3400ba43ed","The role of electrode wettability in electrochemical reduction of carbon dioxide","Li, Mengran (TU Delft ChemE/Materials for Energy Conversion and Storage; University of Queensland); Idros, Mohamed Nazmi (University of Queensland); Wu, Yuming (University of Queensland); Burdyny, T.E. (TU Delft ChemE/Materials for Energy Conversion and Storage); Garg, Sahil (Technical University of Denmark); Zhao, Xiu Song (University of Queensland); Wang, Geoff (University of Queensland); Rufford, Thomas E. (University of Queensland)","","2021","The electrochemical reduction of carbon dioxide (CO2RR) requires access to ample gaseous CO2and liquid water to fuel reactions at high current densities for industrial-scale applications. Substantial improvement of the CO2RR rate has largely arisen from positioning the catalyst close to gas-liquid interfaces, such as in gas-diffusion electrodes. These requirements add complexity to an electrode design that no longer consists of only a catalyst but also a microporous and nanoporous network of gas-liquid-solid interfaces of the electrode. In this three-dimensional structure, electrode wettability plays a pivotal role in the CO2RR because the affinity of the electrode surface by water impacts the observed electrode reactivity, product selectivity, and long-term stability. All these performance metrics are critical in an industrial electrochemical process. This review provides an in-depth analysis of electrode wettability's role in achieving an efficient, selective, and stable CO2RR performance. We first discuss the underlying mechanisms of electrode wetting phenomena and the foreseen ideal wetting conditions for the CO2RR. Then we summarize recent advances in improving cathode performance by altering the wettability of the catalyst layer of gas-diffusion electrodes. We conclude the review by discussing the current challenges and opportunities to develop efficient and selective cathodes for CO2RR at industrially relevant rates. The insights generated from this review could also benefit the advancement of other critical electrochemical processes that involve multiple complex flows in porous electrodes, such as electrochemical reduction of carbon monoxide, oxygen, and nitrogen.","","en","review","","","","","","","","2022-07-08","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:e490df08-a4fa-4ca2-868b-5c3b37706e5b","http://resolver.tudelft.nl/uuid:e490df08-a4fa-4ca2-868b-5c3b37706e5b","Understanding spatiotemporal patterns of typhoon storm surge disasters based on their tropical cyclone track clusters in China","Wang, K. (TU Delft Electrical Engineering, Mathematics and Computer Science; Tsinghua University; Katholieke Universiteit Leuven); Yang, Yongsheng (Tsinghua University); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Katholieke Universiteit Leuven; Universiteit Antwerpen); Huang, Quanyi (Tsinghua University)","","2021","Typhoon storm surge disasters have garnered much attention because of their catastrophic damages. We investigated spatiotemporal patterns of typhoon storm surge disasters based on their tropical cyclone track clusters to support disaster mitigation in China. We aggregated 172 typhoon storm surge disasters in the entire cluster. Then, we used the extended Finite-Mixture-Model to categorize these 172 disasters into three clusters according to their track clusters (westward, northward, and westward shift at the coastline). In general, not all temporal distributions of the frequency and damage showed significant trends in the entire cluster and three clusters from 1983–2018. Between 1983‒2000 and 2001‒2018, the average annual frequency increased, and average annual direct economic loss and average annual fatalities decreased in the entire cluster. Although most temporal patterns in the three clusters were similar to those in the entire cluster, a positive growth ratio in the average annual direct economic loss was apparent between 1983‒2000 and 2001‒2018 in Cluster 3. For spatial patterns, southern and eastern regions were more affected by typhoon storm surge disasters than northern regions. In northern regions, Cluster 2 recorded the most disaster occurrences, direct economic losses, and fatalities. Track characteristics and mitigation measures were introduced to help understand disaster spatiotemporal patterns in the entire cluster and three clusters.","mitigation measures; spatiotemporal patterns; track clustering; tropical cyclone tracks; Typhoon storm surge disaster","en","journal article","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","Safety and Security Science","","",""
"uuid:448774cb-2af6-494e-a314-224bad7dad47","http://resolver.tudelft.nl/uuid:448774cb-2af6-494e-a314-224bad7dad47","Field measurements and numerical modelling of wind-driven exchange flows in a tidal inlet system in the Dutch Wadden Sea","van Weerdenburg, R.J.A. (Deltares); Pearson, S.G. (TU Delft Coastal Engineering; Deltares); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Laan, Stendert (Deltares); Elias, Edwin (Deltares); Tonnon, Pieter Koen (Deltares); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2021","Multiple tidal inlet systems like the Wadden Sea have long been considered as separated basins, bordered by so-called tidal divides. Recently, it was however shown that fluxes of water and sediment occur over the borders of these basins, especially during wind events. In this paper, the wind-driven fluxes over these borders and the residual flow of water through the main inlet are studied. The study is based on flow measurements at the tidal divides and in the main inlet of the Ameland Inlet system in the Dutch Wadden Sea and on numerical modelling. The measurements were carried out during 40 days in the fall of 2017, including both calm conditions and storm events. Numerical simulations of a full year have been used for upscaling results from the measurements to system scale exchange flows, and to unravel the effects of several mechanisms. The wind-driven variability in exchange flows between back-barrier basins at tidal divides was measured in the field and reproduced by the numerical model. Water level set up increases the water depth and thus the conveyance capacity at tidal divides, such that the exchange flows increase in magnitude. The flow conditions due to wind forcing are similar for both tidal divides of the Ameland Basin. The conveyance capacity and therefore the total volume exchange are however different. This leads to a residual compensation flow through the main inlet, which is directed outward (i.e., in the ebb direction) during winds from the prevailing southwestern wind direction. The net discharge through the main inlet is therefore a consequence of the residual flows over the tidal divides.","Exchange flows; Flow measurements; Tidal divides; Wadden sea; Wind-generated currents","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:f3fbdc44-77d6-46a9-abd7-ebfd4570b3f5","http://resolver.tudelft.nl/uuid:f3fbdc44-77d6-46a9-abd7-ebfd4570b3f5","InSbAs Two-Dimensional Electron Gases as a Platform for Topological Superconductivity","Möhle, C.M. (TU Delft QRD/Goswami Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Ke, C. (TU Delft QRD/Goswami Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, Q. (TU Delft QRD/Goswami Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Xiao, Di (Purdue University); Karwal, S. (TU Delft BUS/TNO STAFF; TU Delft QuTech Advanced Research Centre); Lodari, M. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Van De Kerkhof, Vincent (Kavli institute of nanoscience Delft; External organisation); Termaat, Ruben (Kavli institute of nanoscience Delft; Student TU Delft); Scappucci, G. (TU Delft QCD/Scappucci Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Goswami, S. (TU Delft QRD/Goswami Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)","","2021","Topological superconductivity can be engineered in semiconductors with strong spin-orbit interaction coupled to a superconductor. Experimental advances in this field have often been triggered by the development of new hybrid material systems. Among these, two-dimensional electron gases (2DEGs) are of particular interest due to their inherent design flexibility and scalability. Here, we discuss results on a 2D platform based on a ternary 2DEG (InSbAs) coupled to in situ grown aluminum. The spin-orbit coupling in these 2DEGs can be tuned with the As concentration, reaching values up to 400 meV Å, thus exceeding typical values measured in its binary constituents. In addition to a large Landé g-factor of ∼55 (comparable to that of InSb), we show that the clean superconductor-semiconductor interface leads to a hard induced superconducting gap. Using this new platform, we demonstrate the basic operation of phase-controllable Josephson junctions, superconducting islands, and quasi-1D systems, prototypical device geometries used to study Majorana zero modes.","Josephson junctions; spin-orbit interaction; topological superconductivity; tunneling spectroscopy; two-dimensional electron gas","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-05-23","","","QRD/Goswami Lab","","",""
"uuid:576a2614-aa19-4524-b050-f32f632e80e5","http://resolver.tudelft.nl/uuid:576a2614-aa19-4524-b050-f32f632e80e5","Highly Water-Permeable Metal-Organic Framework MOF-303 Membranes for Desalination","Cong, Shenzhen (Tianjin University); Yuan, Ye (Tianjin University); Wang, Jixiao (Tianjin University); Wang, Zhi (Tianjin University); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering); Liu, X. (TU Delft ChemE/Catalysis Engineering; Tianjin University)","","2021","New membrane materials with excellent water permeability and high ion rejection are needed. Metal-organic frameworks (MOFs) are promising candidates by virtue of their diversity in chemistry and topology. In this work, continuous aluminum MOF-303 membranes were prepared on α-Al2O3 substrates via an in situ hydrothermal synthesis method. The membranes exhibit satisfying rejection of divalent ions (e.g., 93.5% for MgCl2 and 96.0% for Na2SO4) on the basis of a size-sieving and electrostatic-repulsion mechanism and unprecedented permeability (3.0 L·m-2·h-1·bar-1·μm). The water permeability outperforms typical zirconium MOF, zeolite, and commercial polymeric reverse osmosis and nanofiltration membranes. Additionally, the membrane material exhibits good stability and low production costs. These merits recommend MOF-303 as a next-generation membrane material for water softening.","","en","journal article","","","","","","Accepted Author Manuscript","","2022-11-23","","","ChemE/Catalysis Engineering","","",""
"uuid:cf0918e9-0256-459a-86a9-fb7f5aa1941e","http://resolver.tudelft.nl/uuid:cf0918e9-0256-459a-86a9-fb7f5aa1941e","Preparing Dicke states in a spin ensemble using phase estimation","Wang, Y. (TU Delft QCD/Terhal Group); Terhal, B.M. (TU Delft QCD/Terhal Group; TU Delft Quantum Computing; Forschungszentrum Jülich GmbH)","","2021","We present a Dicke state preparation scheme which uses global control of N spin qubits: our scheme is based on the standard phase estimation algorithm, which estimates the eigenvalue of a unitary operator. The scheme prepares a Dicke state nondeterministically by collectively coupling the spins to an ancilla qubit via a ZZ interaction, using log2N+1 ancilla qubit measurements. The preparation of such Dicke states can be useful if the spins in the ensemble are used for magnetic sensing: we discuss a possible realization using an ensemble of electronic spins located at diamond nitrogen-vacancy centers coupled to a single superconducting flux qubit. We also analyze the effect of noise and limitations in our scheme.","","en","journal article","","","","","","","","","","","QCD/Terhal Group","","",""
"uuid:70887e9e-3409-4cca-9e13-b427c03e0f9d","http://resolver.tudelft.nl/uuid:70887e9e-3409-4cca-9e13-b427c03e0f9d","Semi-constant Spacing Policy for Leader-Predecessor-Follower Platoon Control via Delayed Measurements Synchronization","Zhang, Y. (TU Delft Transport and Planning; Tongji University); Wang, M. (TU Delft Transport and Planning); Hu, Jia (Tongji University); Bekiaris-Liberis, Nikolaos (Technical University of Crete)","","2021","Constant spacing-based platooning systems cannot guarantee string stability if platoon members only use the preceding vehicle's information. To meet string stability specification, leader-predecessor-follower (LPF) platooning systems are proposed to incorporate the information of both the preceding vehicle and the platoon leader into the control loop. However, string stability of LPF platooning systems is very sensitive to communication and sensing delays. Even a delay of 5 milliseconds may render LPF platooning systems string-unstable. This paper focuses on a new approach to deal with communication and sensing delays in LPF platooning systems. A semi-constant spacing policy that synchronizes delayed measurements of system states obtained from different sources is proposed. This spacing policy aims at tracking the past information of the preceding vehicle to gurantee string stability. Moreover, the delay-synchronizing LPF platooning system puts the same requirements on controller parameters as the nominal LPF platooning system that is not affected by communication and sensing delays. Thus, control gains of the delay-synchronizing LPF platoon can be designed without considering delays.","Communication delay; constant spacing policy; individual vehicle stability; leader-predecessor-follower topology; platooning; string stability; vehicle following","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:d9350bab-7475-4ffa-b78b-945d13a0c965","http://resolver.tudelft.nl/uuid:d9350bab-7475-4ffa-b78b-945d13a0c965","Reinforcement learning control of constrained dynamic systems with uniformly ultimate boundedness stability guarantee","Han, Minghao (Harbin Institute of Technology); Tian, Yuan (Student TU Delft); Zhang, Lixian (Harbin Institute of Technology); Wang, J. (University College London (UCL)); Pan, W. (TU Delft Robot Dynamics)","","2021","Reinforcement learning (RL) is promising for complicated stochastic nonlinear control problems. Without using a mathematical model, an optimal controller can be learned from data evaluated by certain performance criteria through trial-and-error. However, the data-based learning approach is notorious for not guaranteeing stability, which is the most fundamental property for any control system. In this paper, the classic Lyapunov's method is explored to analyze the uniformly ultimate boundedness stability (UUB) solely based on data without using a mathematical model. It is further shown how RL with UUB guarantee can be applied to control dynamic systems with safety constraints. Based on the theoretical results, both off-policy and on-policy learning algorithms are proposed respectively. As a result, optimal controllers can be learned to guarantee UUB of the closed-loop system both at convergence and during learning. The proposed algorithms are evaluated on a series of robotic continuous control tasks with safety constraints. In comparison with the existing RL algorithms, the proposed method can achieve superior performance in terms of maintaining safety. As a qualitative evaluation of stability, our method shows impressive resilience even in the presence of external disturbances.","Constrained dynamic system; Data-based control; Lyapunov's method; Reinforcement learning; Uniformly ultimate boundedness stability","en","journal article","","","","","","","","","","","Robot Dynamics","","",""
"uuid:7722accf-fb33-4781-8348-c85810927b94","http://resolver.tudelft.nl/uuid:7722accf-fb33-4781-8348-c85810927b94","Morphodynamic adaptation of a tidal basin to centennial sea-level rise: The importance of lateral expansion","Guo, Leicheng (East China Normal University); Xu, Fan (East China Normal University); van der Wegen, Mick (IHE Delft Institute for Water Education; Deltares); Townend, Ian (University of Southampton); Wang, Zhengbing (TU Delft Coastal Engineering; East China Normal University; Deltares); He, Qing (East China Normal University)","","2021","Global climate changes have accelerated sea-level rise (SLR), which exacerbates the risks of coastal flooding and erosion. It is of practical interest to understand the long-term hydro-morphodynamic adaptation of coastal systems to SLR at a century time scale. In this work we use a numerical model to explore morphodynamic evolution of a schematized tidal basin in response to SLR of 0.25–2.0 m over 100 years with special emphasis on the impact of lateral basin expansion. Starting from a sloped initial bed, morphodynamic development of the system leads to the formation of alternating bars and meandering channels inside the tidal basin and an ebb-tidal delta extending seaward from the basin. Imposing rising sea level causes progressive inundation of the low-lying floodplains, found along the basin margins, inducing an increase in basin plain area and tidal prism, as well as intertidal area and storage volume. Although the overall channel-shoal structure persists under SLR, lateral shoreline expansion alters the basin hypsometry, leading to enhanced sediment export. The newly-submerged floodplains partly erode, supplying sediment to the system for spatial redistribution, hence buffering the impact of SLR. The vertical accretion rate of the tidal flats inside the tidal basin lags behind the rate of SLR. However, lateral shoreline migration under SLR creates new intertidal flats, compensating intertidal flat loss in the original basin. In contrast, a constrained tidal basin without low-lying floodplains is subject to profound drowning and tidal flat losses under SLR. Overall, the model results suggest that an unconstrained tidal system allowing lateral shoreline migration has buffering capacity for alleviating the drowning impact of SLR by evolving new intertidal areas, sediment redistribution and morphodynamic adjustment. These findings suggest that preserving tidal flats located along the margins of tidal basins (instead of reclaiming them) sustains the system's resilience to SLR.","Accommodation space; Morphodynamic modeling; Sea-level rise; Tidal basin","en","journal article","","","","","","Accepted Author Manuscript","","2022-07-12","","","Coastal Engineering","","",""
"uuid:765a9e4b-ee3c-46c6-ba41-6ad57570613b","http://resolver.tudelft.nl/uuid:765a9e4b-ee3c-46c6-ba41-6ad57570613b","Sbs modified bitumen with organic layered double hydroxides: Compatibility and aging effects on rheological properties","Zhang, Canlin (Fuzhou University); Dong, Hongjun (Fuzhou University); Yan, Zhengli (Fuzhou University); Yu, Meng (Beijing Oriental Yuhong Waterproof Technology Co. Ltd.); Wang, Ting (Fuzhou University); Xu, S. (TU Delft Materials and Environment); Jiang, Zhenliang (Fuzhou University; The Hong Kong University of Science and Technology); Hu, Changbin (Fuzhou University)","","2021","SBS-modified bitumen (SMB) is susceptible to aging, which seriously influences its service performance and life. In order to strengthen the anti-aging ability of SMB, triethoxyvinylsilane was designed to organically modify layered double hydroxides (LDHs) and was applied to modify SMB. The dispersibility and storage stability of LDHs in SMB were markedly enhanced after triethoxyvi-nylsilane organic modification, and the compatibility and storage stability of SBS in bitumen were simultaneously enhanced. Compared with SMB, the introduction of LDHs and organic LDHs (OLDHs) could ameliorate the high-temperature properties of SMB, and the thermostability of SBS in bitumen at a high temperature was also distinctly improved, especially OLDHs. After aging, due to the oxidation of molecular bitumen and the degradation of molecular SBS, SMB became hardened and brittle, and the rheological properties were significantly deteriorated, which had serious im-pacts on the performance of SMB. LDHs can mitigate the detriment of aging to bitumen and SBS, and the deterioration of the rheological properties of SMB is obviously alleviated. As a result of the better dispersibility and storage stability, OLDHs exerted superior reinforcement of the anti-aging ability of SMB.","Aging resistance; Layered double hydroxides; Organic modification; Rheological properties; SBS modified bitumen","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:5bfaf1aa-b26d-487d-b9fc-585e59434eac","http://resolver.tudelft.nl/uuid:5bfaf1aa-b26d-487d-b9fc-585e59434eac","Sustainable construction and financing—asset-backed securitization of expressway’s usufruct with redeemable rights","Zhang, Qiming (Beijing Jiaotong University); Tjia, Linda Yin Nor (City University of Hong Kong); Wang, B. (TU Delft Urban Development Management); Ersoy, A. (TU Delft Urban Development Management)","","2021","Asset-backed securitization will greatly promote the sustainability of infrastructure construction and financing. However, there are quite limited researches conducted in this field. Given the project characteristics of infrastructure project securities, this paper proposes the issuance steps of redeemable asset-backed notes (ABN) based on the infrastructure project’s usufruct as the basic asset. Taking the expressway franchise as an example, the issuing scale and coupon rate of the redeemable ABN are determined by the expected cash flow of the expressway, the term structure of random interest rates, and the option-adjusted spread (OAS). In addition, this research analyzes the duration, convexity, and OAS.","Asset-backed securitization; Infrastructure project; Redeemable asset-backed notes","en","journal article","","","","","","","","","","","Urban Development Management","","",""
"uuid:867583c1-7189-4240-89b3-19ee021ccac0","http://resolver.tudelft.nl/uuid:867583c1-7189-4240-89b3-19ee021ccac0","New innovations in pavement materials and engineering: A review on pavement engineering research 2021","Chen, Jiaqi (Central South University China); Dan, Hancheng (Central South University China); Ding, Yongjie (Chongqing Jiaotong University); Gao, Y. (TU Delft Pavement Engineering); Guo, Meng (Beijing University of Technology); Guo, Shuaicheng (Hunan University); Han, Bingye (Beijing University of Civil Engineering & Architecture); Hong, Bin (Harbin Institute of Technology); Hou, Yue (Beijing University of Technology); Hu, Chichun (South China University of Technology); Hu, Jing (Southeast University); Huyan, Ju (Southeast University; University of Waterloo); Jiang, Jiwang (The Hong Kong Polytechnic University); Jiang, Wei (Chang'an University); Li, Cheng (Chang'an University); Liu, Pengfei (Rheinisch-Westfälische Technische Hochschule); Liu, Yu (Chang'an University); Liu, Zhuangzhuang (Chang'an University); Lu, Guoyang (The Hong Kong Polytechnic University); Ouyang, Jian (Dalian University of Technology); Qu, Xin (Chang'an University); Ren, Dongya (Southwest Jiaotong University); Wang, Chao (Beijing University of Technology); Wang, Chaohui (Chang'an University); Wang, Dawei (Harbin Institute of Technology); Wang, Di (Aalto University); Wang, Hainian (Chang'an University); Wang, Haopeng (University of Nottingham); Xiao, Yue (Wuhan University; Wuhan University of Technology); Xing, Chao (Harbin Institute of Technology); Xu, Huining (Harbin Institute of Technology); Yan, Yu (Tongji University); Yang, Xu (Chang'an University); You, Lingyun (Huazhong University of Science and Technology); You, Zhanping (Michigan Technological University); Yu, Bin (Southeast University); Yu, Huayang (South China University of Technology); Yu, Huanan (Changsha University of Science and Technology); Zhang, Henglong (Hunan University); Zhang, Jizhe (Shandong University); Zhou, Changhong (Guilin University of Electronic Technology); Zhou, Changjun (Dalian University of Technology); Zhu, Xingyi (Tongji University)","","2021","Sustainable and resilient pavement infrastructure is critical for current economic and environmental challenges. In the past 10 years, the pavement infrastructure strongly supports the rapid development of the global social economy. New theories, new methods, new technologies and new materials related to pavement engineering are emerging. Deterioration of pavement infrastructure is a typical multi-physics problem. Because of actual coupled behaviors of traffic and environmental conditions, predictions of pavement service life become more and more complicated and require a deep knowledge of pavement material analysis. In order to summarize the current and determine the future research of pavement engineering, Journal of Traffic and Transportation Engineering (English Edition) has launched a review paper on the topic of “New innovations in pavement materials and engineering: A review on pavement engineering research 2021”. Based on the joint-effort of 43 scholars from 24 well-known universities in highway engineering, this review paper systematically analyzes the research status and future development direction of 5 major fields of pavement engineering in the world. The content includes asphalt binder performance and modeling, mixture performance and modeling of pavement materials, multi-scale mechanics, green and sustainable pavement, and intelligent pavement. Overall, this review paper is able to provide references and insights for researchers and engineers in the field of pavement engineering.","Asphalt binder; Asphalt mixture; Green and sustainable pavement; Intelligent pavement; Modeling of pavement materials; Multi-scale mechanics","en","review","","","","","","","","","","","Pavement Engineering","","",""
"uuid:c35debf4-3cb2-4b36-9802-3b3a5a5cb504","http://resolver.tudelft.nl/uuid:c35debf4-3cb2-4b36-9802-3b3a5a5cb504","The problem of reliable design of vector-field path following in the presence of uncertain course dynamics","Wang, X. (TU Delft Team Bart De Schutter); Roy, Spandan (International Institute of Information Technology); Fari, S. (TU Delft Team Bart De Schutter; Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Baldi, S. (TU Delft Team Bart De Schutter; Southeast University)","","2021","Reliable guidance of fixed-wing Unmanned Aerial Vehicles (UAVs) is challenging, as their high maneuverability exposes them to several dynamical changes and parametric uncertainties. Reliability of state-of-the-art guidance methods is often at stake, as these methods heavily rely on precise UAV course dynamics, assumed in a decoupled first-order form with known time constant. To improve reliability of guidance for fixed-wing UAVs, this work proposes a novel vector field law that can handle uncertain course time constant and state-dependent uncertainty in the course dynamics arising from coupling. Stability is studied in the Lyapunov framework, while reliability of the proposed method is tested on a software-in-the loop UAV simulator. The simulations show that, in the presence of such uncertainty, the proposed method outperforms the standard vector field approaches.","Fixed-wing Unmanned Aerial Vehicles; Guidance navigation and control; Reliable design; Software-in-the loop UAV simulator; Uncertain course dynamics","en","journal article","","","","","","","","","","","Team Bart De Schutter","","",""
"uuid:b177e48a-dd11-486f-9509-a46e478e505a","http://resolver.tudelft.nl/uuid:b177e48a-dd11-486f-9509-a46e478e505a","Quantifying the hierarchy of public transport networks","Buijtenweg, Abel (Student TU Delft); Verma, T. (TU Delft Policy Analysis); Cats, O. (TU Delft Transport and Planning); Donners, Barth (Royal HaskoningDHV); Wang, H. (TU Delft Multimedia Computing)","","2021","Public transport networks constitute critical infrastructure in urban systems. Public transport networks are characterised by their hierarchical structure, yet methods to quantify their underlying hierarchy are lacking. We propose a metric for quantifying the hierarchy in public transport networks which incorporates topological as well as passenger flow information. Our proposed metric consists of three components which jointly define the relative hierarchical position of nodes across the network while the distribution of hierarchy defines the hierarchy of the network itself. We apply the metric to the case studies of Amsterdam and Rotterdam to demonstrate its usefulness in comparing different network states both within and across networks. Using this metric, we identify different patterns in network structures for network states and different spatial distributions of hierarchy between networks. Furthermore, by dividing the network into functional levels, we identify a multilayer hierarchical structure that describes the functionality of the network. The potential application of this metric relates to the assessment of network development scenarios, evaluating bottlenecks and analysing the network vulnerability. Furthermore, the metric is potentially suitable for assessing different network structures such as aviation or maritime networks.","Degree; Hierarchical; Networks; Transportation","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-03-07","","","Policy Analysis","","",""
"uuid:00b58bd6-7a59-4b99-9212-65708ba66285","http://resolver.tudelft.nl/uuid:00b58bd6-7a59-4b99-9212-65708ba66285","An Approach to Map Visibility in The Built Environment from Airborne LiDAR Point Clouds","Zhang, Guan ting (Southeast University); Verbree, E. (TU Delft GIS Technologie); Wang, Xiao jun (Southeast University)","","2021","Sustainable development can only be achieved with an innovative improvement from the way we currently analyze, design, build and manage our urban spaces. Current digital analysis and design methods for cities, such as visibility analysis, deeply rely on mapping and modeling techniques. However, most methods fall short of depicting the real visual landscape in the urban realm and this could bring a significant error in visibility calculations which may lead to an improper decision for urban spaces. The technical development of light detection and ranging(LiDAR) technology introduces new approaches for urban study. LiDAR utilizes point clouds including thousands or even millions of georeferenced points, and thus can support 3-D digital representation of urban landscape with detailed information and high resolution. Besides the superiority in representing urban landscape, LiDAR point clouds also has a clear advantage in quantitative analysis and provides better visibility than traditional models. In this paper, we first introduced a novel approach to map visibility in the urban built environment involving vegetation data directly using airborne LiDAR point clouds. This approach calculates neighborhood statistics for occlusion detection. Then we presented 2 case with different scenarios showing how our approach can be used to obtain a precise visibility in an urban area in the Netherlands. At last, we discussed how point clouds based visibility models can be further explored and can better assist urban design.","airborne LiDAR; Buildings; built environment; Laser radar; point cloud; Three-dimensional displays; urban area; Urban areas; Vegetation; Vegetation mapping; visibility analysis; visual environment; Visualization","en","journal article","","","","","","","","","","","GIS Technologie","","",""
"uuid:5f7df05f-d237-4e2e-8260-88a9e4d365fc","http://resolver.tudelft.nl/uuid:5f7df05f-d237-4e2e-8260-88a9e4d365fc","The Mechanical Properties and Elastic Anisotropy of η’-Cu6Sn5 and Cu3Sn Intermetallic Compounds","Ding, Chao (Guilin University of Electronic Technology); Wang, Jian (Guilin University of Electronic Technology); Liu, Tianhan (Guilin University of Electronic Technology); Qin, Hongbo (Guilin University of Electronic Technology); Yang, Daoguo (Guilin University of Electronic Technology); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials; Guilin University of Electronic Technology)","","2021","Full intermetallic compound (IMC) solder joints present fascinating advantages in high-temperature applications. In this study, the mechanical properties and elastic anisotropy of η’-Cu6Sn5 and Cu3Sn intermetallic compounds were investigated using first-principles calculations. The values of single-crystal elastic constants, the elastic (E), shear (G), and bulk (B) moduli, and Poisson’s ratio (ν) were identified. In addition, the two values of G/B and ν indicated that the two IMCs were ductile materials. The elastic anisotropy of η’-Cu6Sn5 was found to be higher than Cu3Sn by calculating the universal anisotropic index. Furthermore, an interesting discovery was that the above two types of monocrystalline IMC exhibited mechanical anisotropic behavior. Specifically, the anisotropic degree of E and B complied with the following relationship: η’-Cu6Sn5 > Cu3Sn; however, the relationship was Cu3Sn > η’-Cu6Sn5 for the G. It is noted that the anisotropic degree of E and G was similar for the two IMCs. In addition, the anisotropy of the B was higher than the G and E, respectively, for η’-Cu6Sn5; however, in the case of Cu3Sn, the anisotropic degree of B, G, and E was similar.","Elastic anisotropic; First-principles calculates; Intermetallic compounds; Mechanical properties","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:282a8143-e41f-4625-83dc-420f4f179049","http://resolver.tudelft.nl/uuid:282a8143-e41f-4625-83dc-420f4f179049","Sizing and Control of a Hybrid Ship Propulsion System Using Multi-Objective Double-Layer Optimization","Wang, X. (TU Delft Transport Engineering and Logistics); Shipurkar, U. (TU Delft Transport Engineering and Logistics; Maritime Research Institute Netherlands (MARIN)); Haseltalab, A. (TU Delft Transport Engineering and Logistics); Polinder, H. (TU Delft Transport Engineering and Logistics); Claeys, Frans (GEOxyz); Negenborn, R.R. (TU Delft Transport Engineering and Logistics)","","2021","Ship hybridization has received some interests recently in order to achieve the emission target by 2050. However, designing and optimizing a hybrid propulsion system is a complicated problem. Sizing components and optimizing energy management control are coupled with each other. This paper applies a nested double-layer optimization architecture to optimize the sizing and energy management of a hybrid offshore support vessel. Three different power sources, namely diesel engines, batteries and fuel cells, are considered which increases the complexity of the optimization problem. The optimal sizing of the components and their corresponding energy management strategies are illustrated. The effects of the operational profiles and the emission reduction targets on the hybridization design are studied for this particular type of vessel. The results prove that a small emission reduction target of about 10% can be achieved by improving the diesel engine efficiency using the batteries only while the achievement of a larger emission reduction target mainly depends on the amount of the hydrogen and/or on-shore charging electricity consumed. Some design guidelines for hybridization are derived for this particular ship which could be also valid for other vessels with similar operational profiles.","Batteries; control; Energy management; energy management; Fuel cells; Hybrid; Hydrogen; Marine vehicles; offshore support vessel; Optimization; Propulsion; sizing","en","journal article","","","","","","","","","","","Transport Engineering and Logistics","","",""
"uuid:5f86a024-4935-4574-b162-0c1cb9cf0976","http://resolver.tudelft.nl/uuid:5f86a024-4935-4574-b162-0c1cb9cf0976","Game theoretic lane change strategy for cooperative vehicles under perfect information","Ladino, Andres (COSYS); Wang, M. (TU Delft Transport and Planning)","Li, Ruimin (editor); He, Zhengbing (editor)","2021","Lane change maneuvers are main causes of traffic turbulence at highway bottlenecks. We propose a dynamic game framework to derive the system optimum strategy for a network of cooperative vehicles interacting at a merging bottleneck. Cooperative vehicles on the highway mainline seek for optimal strategies (i.e., whether and when to perform courtesy lane change to facilitate the merging vehicle) to minimize their cost, while taking into account potential future interactions at the merging section while minimizing the distance traveled on the acceleration lane. An optimal strategy is found by minimizing the joint cost of all interacting vehicles while respecting behavioral and physical constraints. Numerical examples show the feasibility of the approach in capturing the nature of conflict and cooperation during the merging process, and demonstrate the benefits of sharing information and cooperative control for connected and automated vehicles.","road traffic control; roads; road vehicles; game theory; road safety; road traffic; traffic engineering computing","en","book chapter","Institution of Engineering and Technology","","","","","","","","","","Transport and Planning","","",""
"uuid:ede6e2a0-21d0-4ce5-b878-bb7601e9e60b","http://resolver.tudelft.nl/uuid:ede6e2a0-21d0-4ce5-b878-bb7601e9e60b","Position correction in dust storm forecasting using LOTOS-EUROS v2.1: Grid-distorted data assimilation v1.0","Jin, J. (TU Delft Mathematical Physics; Nanjing University of Information Sciences and Technology); Segers, Arjo (TNO); Lin, H.X. (TU Delft Mathematical Physics); Henzing, Bas (TNO); Wang, X. (TU Delft Mathematical Physics); Heemink, A.W. (TU Delft Mathematical Physics); Liao, Hong (Nanjing University of Information Sciences and Technology)","","2021","When calibrating simulations of dust clouds, both the intensity and the position are important. Intensity errors arise mainly from uncertain emission and sedimentation strengths, while position errors are attributed either to imperfect emission timing or to uncertainties in the transport. Though many studies have been conducted on the calibration or correction of dust simulations, most of these focus on intensity solely and leave the position errors mainly unchanged. In this paper, a grid-distorted data assimilation, which consists of an image-morphing method and an ensemble-based variational assimilation, is designed for realigning a simulated dust plume to correct the position error. This newly developed grid-distorted data assimilation has been applied to a dust storm event in May 2017 over East Asia. Results have been compared for three configurations: a traditional assimilation configuration that focuses solely on intensity correction, a grid-distorted data assimilation that focuses on position correction only and the hybrid assimilation that combines these two. For the evaluated case, the position misfit in the simulations is shown to be dominant in the results. The traditional emission inversion only slightly improves the dust simulation, while the grid-distorted data assimilation effectively improves the dust simulation and forecasting. The hybrid assimilation that corrects both position and intensity of the dust load provides the best initial condition for forecasting of dust concentrations.","","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:00dc2380-4e4c-4a77-bad6-048800dd8b1e","http://resolver.tudelft.nl/uuid:00dc2380-4e4c-4a77-bad6-048800dd8b1e","Aeroelastic optimisation of manufacturable tow-steered composite wings with cruise shape constraint and gust loads","Wang, Z. (TU Delft Aerospace Structures & Computational Mechanics); Peeters, D.M.J. (TU Delft Aerospace Structures & Computational Mechanics); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics)","","2021","In the structural design of aircraft wings, aeroelastic tailoring is used to control the aeroelastic deformation to improve the aerostructural performance by making use of directional stiffness. Recently, tow-steered composites, where the fibre angles continuously vary within each ply, have been proven to have the potential to further expand the advantages of aeroelastic tailoring. This work extends TU Delft aeroelastic tailoring framework PROTEUS by introducing a lay-up retrieval step, so that it can be used for the conceptual design of tow-steered composite wing structures. In the extended framework, aeroelastic tailoring and lay-up retrieval are sequentially and iteratively performed to take static and dynamic loads, manufacturing and cruise shape constraints into consideration. The first step is carried out using PROTEUS, in which the lamination parameters and thickness of the wing sections are optimised under manoeuvre and gust load conditions. Further, for ensuring optimal aircraft performance in cruise flight conditions, the jig twist distribution is allowed to be optimised to maintain a desired prescribed cruise shape. In the second step, the stacking sequence, including minimum steering radius constraint, is retrieved. Since the lamination parameters cannot be matched exactly during the retrieval step, the constraints are checked, and tightened to take the performance loss during retrieval into account. The first step is repeated until all constraints are satisfied after fibre angle retrieval. To demonstrate the usefulness of the proposed optimisation framework, it is applied to the design of the NASA Common Research Model (CRM) wing, of which the objective is minimizing wing mass subjected to aerostructural design constraints, such as aeroelastic stability, aileron effectiveness, material strength and buckling load.","","en","journal article","","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:fd1d3321-6a8f-442e-9d62-e83ab0369e61","http://resolver.tudelft.nl/uuid:fd1d3321-6a8f-442e-9d62-e83ab0369e61","Practical Threshold Multi-Factor Authentication","Li, Wenting (Peking University); Cheng, Haibo (Peking University); Wang, Ping (Peking University); Liang, K. (TU Delft Cyber Security)","","2021","Multi-factor authentication (MFA) has been widely used to safeguard high-value assets. Unlike single-factor authentication (e.g., password-only login), t-factor authentication (tFA) requires a user always to carry and present t specified factors so as to strengthen the security of login. Nevertheless, this may restrict user experience in limiting the flexibility of factor usage, e.g., the user may prefer to choose any factors at hand for login authentication. To bring back usability and flexibility without loss of security, we introduce a new notion of authentication, called (t, n) threshold MFA, that allows a user to actively choose t factors out of n based on preference. We further define the “most-rigorous” multi-factor security model for the new notion, allowing attackers to control public channels, launch active/passive attacks, and compromise/corrupt any subset of parties as well as factors. We state that the model can capture the most practical security needs in the literature. We design a threshold MFA key exchange (T-MFAKE) protocol built on the top of a threshold oblivious pseudorandom function and an authenticated key exchange protocol. Our protocol achieves the “highest-attainable” security against all attacking attempts in the context of parties/factors being compromised/corrupted. As for efficiency, our design only requires 4+t exponentiations, 2 multi-exponentiations and 2 communication rounds. Compared with existing tFA schemes, even the degenerated (t, t) version of our protocol achieves the strongest security (stronger than most schemes) and higher efficiency on computational and communication. We instantiate our design on real-world platform to highlight its practicability and efficiency.","Authentication; Biometrics (access control); Key Exchange; Multi-Factor Authentication; Password; Protocols; Security; Servers; Threshold; Usability","en","journal article","","","","","","","","","","","Cyber Security","","",""
"uuid:7544cd5e-5474-4b64-87ac-c73c504e4d41","http://resolver.tudelft.nl/uuid:7544cd5e-5474-4b64-87ac-c73c504e4d41","Through-Screen Visible Light Sensing Empowered by Embedded Deep Learning","Liu, Hao (Student TU Delft); Ye, Hanting (TU Delft Embedded Systems); Yang, J. (TU Delft Web Information Systems); Wang, Q. (TU Delft Embedded Systems)","","2021","Motivated by the trend of realizing full screens on devices such as smartphones, in this work we propose through-screen sensing with visible light for the application of fingertip air-writing. The system can recognize handwritten digits with under-screen photodiodes as the receiver. The key idea is to recognize the weak light reflected by the finger when the finger writes the digits on top of a screen. The proposed air-writing system has immunity to scene changes because it has a fixed screen light source. However, the screen is a double-edged sword as both a signal source and a noise source. We propose a data preprocessing method to reduce the interference of the screen as a noise source. We design an embedded deep learning model, a customized model ConvRNN, to model the spatial and temporal patterns in the dynamic and weak reflected signal for air-writing digits recognition. The evaluation results show that our through-screen fingertip air-writing system with visible light can achieve accuracy up to 91%. Results further show that the size of the customized ConvRNN model can be reduced by 94% with less than a 10% drop in performance.","embedded AI; embedded deep learning; Through-screen sensing","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Embedded Systems","","",""
"uuid:ce4953a7-4fb0-4122-9e5c-ed6322758f22","http://resolver.tudelft.nl/uuid:ce4953a7-4fb0-4122-9e5c-ed6322758f22","A computational framework for coating fatigue analysis of wind turbine blades due to rain erosion","Hu, Weifei (School of Mechanical Engineering, Zhejiang University); Chen, Weiyi (School of Mechanical Engineering, Zhejiang University); Wang, Xiaobo (School of Mechanical Engineering, Zhejiang University); Jiang, Zhiyu (University of Agder); Wang, Yeqing (Syracuse University); Verma, Amrit Shankar (TU Delft Aerospace Manufacturing Technologies); Teuwen, Julie J.E. (TU Delft Aerospace Manufacturing Technologies)","","2021","The rain-induced fatigue damage in the wind turbine blade coating has attracted increasing attention owing to significant repair and maintenance costs. The present paper develops an improved computational framework for analyzing the wind turbine blade coating fatigue induced by rain erosion. The paper first presents an extended stochastic rain field simulation model that considers different raindrop shapes (spherical, flat, and spindle), raindrop sizes, impact angles, and impact speeds. The influence of these raindrop characteristics on the impact stress of the blade coating is investigated by a smoothed particle hydrodynamics approach. To address the expensive computational time, a stress interpolation method is proposed to calculate the impact stress of all raindrops in a random rain event. Furthermore, coating fatigue analysis is performed by including the fatigue crack initiation in the incubation period and the fatigue crack propagation in the mass-loss-rate increasing period due to raindrop impact. Finally, the proposed computational framework is verified by comparing the estimated fatigue life with those obtained in literature. The results from the study show that by incorporating the statistics of rainfall data, the proposed framework could be used to calculate the expected fatigue life of the blade coating due to rain erosion.","Crack propagation; Fatigue analysis; Rain erosion; Raindrop impact; Smoothed particle hydrodynamics; Wind turbine blade","en","journal article","","","","","","","","2023-02-08","","","Aerospace Manufacturing Technologies","","",""
"uuid:6ff6d617-5c13-449b-b2d2-6371c5a19c9a","http://resolver.tudelft.nl/uuid:6ff6d617-5c13-449b-b2d2-6371c5a19c9a","SpiderWeb: Enabling Through-Screen Visible Light Communication","Ye, Hanting (TU Delft Embedded Systems); Wang, Q. (TU Delft Embedded Systems)","","2021","We are now witnessing a trend of realizing full-screen on electronic devices such as smartphones to maximize their screen-to-body ratio for a better user experience. Thus the bezel/narrow-bezel on today's devices to host various line-of-sight sensors would disappear. This trend not only is forcing sensors like the front cameras to be placed under the screen of devices, but also will challenge the deployment of the emerging Visible Light Communication (VLC) technology, a paradigm for the next-generation wireless communication. In this work, we propose the concept of through-screen VLC with photosensors placed under Organic Light-Emitting Diode (OLED) screen. Though being transparent, an OLED screen greatly attenuates the intensity of passing-through light, degrading the efficiency of intensity-based VLC systems. In this paper, we instead exploit the color domain to build SpiderWeb, a through-screen VLC system. For the first time, we observe that an OLED screen introduces a color-pulling effect at photosensors, affecting the decoding of color-based VLC signals. Motivated by this observation and by the structure of spider's web, we design the SWebCSK Color-Shift Keying modulation scheme and a slope-based demodulation method, which can eliminate the color-pulling effect. We prototype SpiderWeb with off-the-shelf hardware and evaluate its performance thoroughly under various scenarios. The results show that compared to existing solutions, our solutions can reduce the bit error rate by two orders of magnitude and can achieve a 3.4x data rate.","color-pulling effect; Through-screen VLC; transparent OLED screen","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Embedded Systems","","",""
"uuid:5b32564a-d0e9-4917-b4f2-38812b17d414","http://resolver.tudelft.nl/uuid:5b32564a-d0e9-4917-b4f2-38812b17d414","Seamless Active Morphing Wing Simultaneous Gust and Maneuver Load Alleviation","Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics); Mkhoyan, T. (TU Delft Aerospace Structures & Computational Mechanics); Mkhoyan, A. (TU Delft Aerospace Structures & Computational Mechanics); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics)","","2021","This paper deals with the simultaneous gust and maneuver load alleviation problem of a seamless active morphing wing. The incremental nonlinear dynamic inversion with quadratic programming control allocation and virtual shape functions (denoted as INDI-QP-V) is proposed to fulfill this goal. The designed control allocator provides an optimal solution while satisfying actuator position constraints, rate constraints, and relative position constraints. Virtual shape functions ensure the smoothness of the morphing wing at every moment. In the presence of model uncertainties, external disturbances, and control allocation errors, the closed-loop stability is guaranteed in the Lyapunov sense. Wind tunnel tests demonstrate that INDI-QP-V can make the seamless wing morph actively to resist “1-cos” gusts and modify the spanwise lift distribution at the same time. The wing root shear force and bending moment have been alleviated by more than 44% despite unexpected actuator fault and nonlinear backlash. Moreover, during the experiment, all the input constraints were satisfied, the wing shape was smooth all the time, and the control law was executed in real time. Furthermore, as compared with the linear quadratic Gaussian control, the hardware implementation of INDI-QP-V is easier; the robust performance of INDI-QP-V is also superior.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-11-29","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:b5acef2b-6f87-4d59-9d28-902fd63fea2a","http://resolver.tudelft.nl/uuid:b5acef2b-6f87-4d59-9d28-902fd63fea2a","Energy Self-Sustainability in Full-Spectrum 6G","Hu, Jie (University of Electronic Science and Technology of China); Wang, Q. (TU Delft Embedded Systems); Yang, Kun (University of Essex)","","2021","Full-spectrum ranging from sub-6 GHz to THz and visible light will be exploited in 6G in order to reach unprecedented key-performance-indica-tors. However, an extraordinary amount of energy will be consumed by network infrastructure, while functions of massively deployed Internet of Everything (IoE) devices are limited by embedded batteries. Therefore, energy self-sustainable (ESS) 6G is proposed in this article. First of all, it may achieve network-wide energy efficiency by exploiting cell-free and airborne access networks as well as by implementing intelligent reflecting surfaces (IRSs). Second, by exploiting radio-frequency/visible-light signals for on-demand wireless information and energy provision (WIEP) and for enabling passive backscatter communication, 'zero-energy' IoE devices may become a reality. Furthermore, IoE devices actively adapt their transceivers for better performance to a dynamic environment. Case studies of cell-free and IRS based WIEP are provided for demonstrating the advantage of our proposed architecture in terms of energy self-sustainability. This article aims to provide a first glance at primary designing principles of ESS-6G.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-08-31","","","Embedded Systems","","",""
"uuid:e3c86c6b-3aed-460f-b772-773345b65087","http://resolver.tudelft.nl/uuid:e3c86c6b-3aed-460f-b772-773345b65087","Assessing the signal quality of electrocardiograms from varied acquisition sources: A generic machine learning pipeline for model generation","Albaba, Adnan (Katholieke Universiteit Leuven; IMEC); Simões-Capela, Neide (Katholieke Universiteit Leuven; IMEC); Wang, Yuyang (Student TU Delft); Hendriks, R.C. (TU Delft Signal Processing Systems); De Raedt, Walter (IMEC); Van Hoof, Chris (IMEC; Katholieke Universiteit Leuven)","","2021","Background and objective: Long-term electrocardiogram monitoring comes at the expense of signal quality. During unconstrained movements, the electrocardiogram is often corrupted by motion artefacts, which can lead to inaccurate physiological information. In this situation, automated quality assessment methods are useful to increase the reliability of the measurements. A generic machine learning pipeline that generates classification models for electrocardiogram quality assessment is presented in this article. The presented pipeline is tested on signals from varied acquisition sources, towards selecting segments that can be used for heart rate analysis in lifestyle applications. Methods: Electrocardiogram recordings from traditional, wearable and ubiquitous devices, are segmented in 10 s windows and manually labeled by experienced researchers into two quality classes. To capture the electrocardiogram dynamics, a comprehensive set of 43 features is extracted from each segment, based on the time-domain signal, its Fast Fourier Transform, the Autocorrelation function and the Stationary Wavelet Transform. To select the most relevant features for each acquisition source we employ both a customized hybrid approach and the state-of-the-art Neighborhood Component Analysis method and compare them. Support Vector Machines (SVM), Decision Trees, K-Nearest-Neighbors and supervised ensemble methods are tested as possible binary classifiers. Results: The results for the best performing models on traditional, wearable and ubiquitous electrocardiogram datasets are, respectively: balanced-accuracy: 89%, F1-score: 93% with the Fine Gaussian SVM model and 10 features; balanced-accuracy: 93%, F1-score: 93% with the Fine Gaussian SVM model and 11 features; balanced-accuracy: 95%, F1-score: 86%, with the Fine Gaussian SVM model and 8 features. Conclusions: According to the results, our generic pipeline can generate classification models tailored to individual acquisition sources, provided that a standard Lead I or Lead II is available. Such models accurately establish whether the electrocardiogram quality is good or bad for heart rate analysis. Furthermore, removing bad quality segments decreases errors in heart rate calculation.","Classification; Electrocardiogram; Feature selection; Motion artefact; Non-contact; Signal quality; Ubiquitous; Wearables","en","journal article","","","","","","Accepted author manuscript","","2021-12-21","","","Signal Processing Systems","","",""
"uuid:3c4927ae-dcb5-4b63-af88-50016e7def1e","http://resolver.tudelft.nl/uuid:3c4927ae-dcb5-4b63-af88-50016e7def1e","Experimental and numerical study on lateral and longitudinal resistance of ballasted track with nailed sleeper","Guo, Y. (TU Delft Railway Engineering); Zong, Lu (Beijing Jiaotong University); Markine, V.L. (TU Delft Railway Engineering); Wang, Xinyu (Beijing Jiaotong University); Jing, Guoqing (Beijing Jiaotong University)","","2021","Lateral and longitudinal resistance of ballasted track are two main indicators for the track stability quantification. Aiming at improving the lateral and longitudinal resistance, nailed sleeper is studied with single sleeper push tests (SSPTs) and discrete element modelling (DEM). The SSPTs were applied to study how much resistance the nailed sleeper can improve, considering different nail lengths (100, 200, 400 mm), and also used to calibrate and validate the DEM models. With the validated DEM models, different simulation conditions were performed and compared to confirm the optimal nail length (100, 200 mm) and nail number (2, 4). Results show that applying nailed sleepers improves the lateral resistance by 53.7% and the longitudinal resistance by 39.2%. 4 nails, compared to 2 nails, can increase lateral and longitudinal resistance by 20.2% and 10.6% (nail length: 100 mm) as well as 37.0% and 33.5% (nail length: 200 mm), respectively.","ballasted track; DEM; lateral resistance; Longitudinal resistance; nailed sleeper; track stability","en","journal article","","","","","","Accepted Author Manuscript","","2022-01-14","","","Railway Engineering","","",""
"uuid:4ef337e8-ca2d-4a50-b705-a69c78a77703","http://resolver.tudelft.nl/uuid:4ef337e8-ca2d-4a50-b705-a69c78a77703","Effect of different aqueous solutions on physicochemical properties of asphalt binder","Zou, Yingxue (Wuhan University of Technology); Amirkhanian, Serji (University of South Alabama); Xu, S. (TU Delft Materials and Environment); Li, Yuanyuan (Wuhan University of Technology); Wang, Yafei (Wuhan University of Technology); Zhang, Jianwei (Wuhan University of Technology)","","2021","Aqueous solution is one of the main factors of asphalt pavement disease. However, the physicochemical changes of asphalt are ambiguous during immersion in different aqueous solutions. This study evaluated the physicochemical properties of asphalt under the action of different aqueous solutions to further understand the mechanism of moisture erosion. The morphology, chemical structure and four components of asphalt were observed after immersion, while the pH value, total organic carbon (TOC) and characteristic functional groups of residual solutions were monitored. The test results showed that aqueous solution could change the bee structure on the asphalt surface and increased the mean roughness. The carbonyl index (IC=O) and sulfoxide index (IS=O) of asphalt increased with immersion time. And the asphaltenes of asphalt fluctuated and eventually increased during immersion. Solute could accelerate the erosion on asphalt through interaction, the degree of which increased in the order, Na2SO4 saline < NaCl saline < pH 3 acid < pH 11 alkali.","Aqueous solutions; Asphalt; Components; Morphology; Structure","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:f34cfcbb-10ff-421f-8876-974c718b1e79","http://resolver.tudelft.nl/uuid:f34cfcbb-10ff-421f-8876-974c718b1e79","Plasmonic tweezers: for nanoscale optical trapping and beyond","Zhang, Yuquan (Shenzhen University); Min, Changjun (Shenzhen University); Dou, X. (TU Delft ImPhys/Optics; Shenzhen University); Wang, Xianyou (Shenzhen University); Urbach, Paul (TU Delft ImPhys/Optics); Somekh, Michael G. (Shenzhen University); Yuan, Xiaocong (Shenzhen University)","","2021","Optical tweezers and associated manipulation tools in the far field have had a major impact on scientific and engineering research by offering precise manipulation of small objects. More recently, the possibility of performing manipulation with surface plasmons has opened opportunities not feasible with conventional far-field optical methods. The use of surface plasmon techniques enables excitation of hotspots much smaller than the free-space wavelength; with this confinement, the plasmonic field facilitates trapping of various nanostructures and materials with higher precision. The successful manipulation of small particles has fostered numerous and expanding applications. In this paper, we review the principles of and developments in plasmonic tweezers techniques, including both nanostructure-assisted platforms and structureless systems. Construction methods and evaluation criteria of the techniques are presented, aiming to provide a guide for the design and optimization of the systems. The most common novel applications of plasmonic tweezers, namely, sorting and transport, sensing and imaging, and especially those in a biological context, are critically discussed. Finally, we consider the future of the development and new potential applications of this technique and discuss prospects for its impact on science.","","en","review","","","","","","","","","","","ImPhys/Optics","","",""
"uuid:280b59f8-1644-426d-9298-40d937885648","http://resolver.tudelft.nl/uuid:280b59f8-1644-426d-9298-40d937885648","Photoacoustic flow velocity imaging based on complex field decorrelation","Pakdaman Zangabad, Reza (Erasmus MC); Iskander-Rizk, Sophinese (Erasmus MC); van der Meulen, P.Q. (TU Delft Signal Processing Systems); Meijlink, Bram (Erasmus MC); Kooiman, Klazina (Erasmus MC); Wang, Tianshi (Erasmus MC); van der Steen, A.F.W. (TU Delft ImPhys/Medical Imaging; Erasmus MC; Chinese Academy of Sciences); van Soest, Gijs (Erasmus MC)","","2021","Photoacoustic (PA) imaging can be used to monitor flowing blood inside the microvascular and capillary bed. Ultrasound speckle decorrelation based velocimetry imaging was previously shown to accurately estimate blood flow velocity in mouse brain (micro-)vasculature. Translating this method to photoacoustic imaging will allow simultaneous imaging of flow velocity and extracting functional parameters like blood oxygenation. In this study, we use a pulsed laser diode and a quantitative method based on normalized first order field autocorrelation function of PA field fluctuations to estimate flow velocities in an ink tube phantom and in the microvasculature of the chorioallantoic membrane of a chicken embryo. We demonstrate how the decorrelation time of signals acquired over frames are related to the flow speed and show that the PA flow analysis based on this approach is an angle independent flow velocity imaging method.","Functional imaging; Photoacoustic flow velocity imaging; Pulsed Diode Laser; Speckle dynamics","en","journal article","","","","","","","","","","","Signal Processing Systems","","",""
"uuid:b6a3d09e-c0ce-49cc-88b6-2bb7a01e0bf6","http://resolver.tudelft.nl/uuid:b6a3d09e-c0ce-49cc-88b6-2bb7a01e0bf6","A generic high-throughput microstructure classification and quantification method for regular SEM images of complex steel microstructures combining EBSD labeling and deep learning","Shen, Chunguang (Northeastern University); Wang, Chenchong (Northeastern University); Huang, Minghao (Northeastern University); Xu, Ning (Northeastern University); van der Zwaag, S. (TU Delft Novel Aerospace Materials); Xu, W. (TU Delft Novel Aerospace Materials; Northeastern University)","","2021","We present an electron backscattered diffraction (EBSD)-trained deep learning (DL) method integrating traditional material characterization informatics and artificial intelligence for a more accurate classification and quantification of complex microstructures using only regular scanning electron microscope (SEM) images. In this method, EBSD analysis is applied to produce accurate ground truth data for guiding the DL model training. An U-Net architecture is used to establish the correlation between SEM input images and EBSD ground truth data using only small experimental datasets. The proposed method is successfully applied to two engineering steels with complex microstructures, i.e., a dual-phase (DP) steel and a quenching and partitioning (Q&P) steel, to segment different phases and quantify phase content and grain size. Alternatively, once properly trained the method can also produce quasi-EBSD maps by inputting regular SEM images. The good generality of the trained models is demonstrated by using DP and Q&P steels not associated with the model training. Finally, the method is applied to SEM images with various states, i.e., different imaging modes, image qualities and magnifications, demonstrating its good robustness and strong application ability. Furthermore, the visualization of feature maps during the segmenting process is utilised to explain the mechanism of this method's good performance.","Deep learning; Electron backscatter diffraction; Microstructure quantification; Small sample problem","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-12-01","","","Novel Aerospace Materials","","",""
"uuid:6c96293f-aedc-45ca-88fe-888f0f762333","http://resolver.tudelft.nl/uuid:6c96293f-aedc-45ca-88fe-888f0f762333","Numerical analysis of tiny-focal-spot generation by focusing linearly, circularly, and radially polarized beams through a micro/nanoparticle","Shi, Rui (Friedrich Schiller University Jena; LightTrans International UG, Jena); Wang, Zongzhao (Friedrich Schiller University Jena; LightTrans International UG, Jena); Hung, S. (TU Delft Team Raf Van de Plas); Hellmann, Christian (Wyrowski Photonics UG, Jena); Wyrowski, Frank (Friedrich Schiller University Jena)","","2021","Obtaining a tiny focal spot is desired for super resolution. We do a vectorial numerical analysis of the linearly, circularly, and radidally polarized electromagnetic fields being focused through a dielectric micro/nanoparticle of size comparable to the wavelength. We find tiny focal spots (up to ∼ 0.05 λ2) can be obtained behind micro/nanoparticles of various shapes, e.g. spherical, disk-shaped, and cuboid micro/nanoparticles. Furthermore, we also investigate the influence of the misalignment of a real lens system on the tiny focal spots. We find that tiny focal spots can still be generated even though they are distorted due to the misalignment.","","en","journal article","","","","","","","","","","","Team Raf Van de Plas","","",""
"uuid:43d3ee43-4ee0-4c73-bf01-e9deafc4c03d","http://resolver.tudelft.nl/uuid:43d3ee43-4ee0-4c73-bf01-e9deafc4c03d","Cascade CO2 electroreduction enables efficient carbonate-free production of ethylene","Ozden, Adnan (University of Toronto); Wang, Y. (University of Toronto); Li, Fengwang (University of Toronto); Luo, Mingchuan (University of Toronto); Sisler, Jared (University of Toronto); Thevenon, Arnaud (California Institute of Technology); Rosas-Hernández, Alonso (California Institute of Technology); Burdyny, T.E. (TU Delft ChemE/Materials for Energy Conversion and Storage); Lum, Yanwei (University of Toronto)","","2021","CO 2 electroreduction offers a route to net-zero-emission production of C 2H 4—the most-produced organic compound. However, the formation of carbonate in this process causes loss of CO 2 and a severe energy consumption/production penalty. Dividing the CO 2-to-C 2H 4 process into two cascading steps—CO 2 reduction to CO in a solid-oxide electrolysis cell (SOEC) and CO reduction to C 2H 4 in a membrane electrode assembly (MEA) electrolyser—would enable carbonate-free C 2H 4 electroproduction. However, this cascade approach requires CO-to-C 2H 4 with energy efficiency well beyond demonstrations to date. Here, we present a layered catalyst structure composed of a metallic Cu, N-tolyl-tetrahydro-bipyridine, and SSC ionomer that enables efficient CO-to-C 2H 4 in a MEA electrolyser. In the full SOEC-MEA cascade approach, we achieve CO 2-to-C 2H 4 with no loss of CO 2 to carbonate and a total energy requirement of ~138 GJ (ton C 2H 4) −1, representing a ~48% reduction in energy intensity compared with the direct route.","carbon utilization; catalyst design; CO electroreduction; electrolyser; energy efficiency; ethylene electrolysis; membrane electrode assembly; molecular catalyst; solid-oxide electrolyser","en","journal article","","","","","","Accepted Author Manuscript","","2022-02-15","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:35cf6484-2971-4fc6-8df2-2653ca354e6e","http://resolver.tudelft.nl/uuid:35cf6484-2971-4fc6-8df2-2653ca354e6e","Towards an understanding of diffusion mechanism of bio-rejuvenators in aged asphalt binder through molecular dynamics simulation","Ding, Heyang (Chang'an University); Wang, Hainian (Chang'an University); Qu, Xin (Chang'an University); Varveri, Aikaterini (TU Delft Pavement Engineering); Gao, Junfeng (Chang'an University); You, Zhanping (Michigan Technological University)","","2021","The use of reclaimed asphalt pavement (RAP) is a hot research topic in the field of road engineering, as there are still many issues to overcome so as to become standard engineering applications. The diffusion of virgin/aged asphalt binder is a key process to improve RAP performance. In this study, the asphalt binder diffusion models were developed by molecular dynamics (MD) simulation. Two kinds of bio-rejuvenators (BR-1 and BR-5) were chosen to represent the straight-chain and aromatic structures, respectively. The method of relative concentration, radial distribution function (RDF), and microstructure morphology were used to evaluate the effect of bio-rejuvenators on the diffusion process of virgin/aged asphalt binder. The results showed that bio-rejuvenators had a positive effect on the fusion process between virgin and aged asphalt binder. The volume diffusion coefficient based on asphalt binder diffusion models indicated that the bio-rejuvenators accelerated the fusion process between the virgin and asphalt binder. After adding bio-rejuvenators to the aged asphalt binder, the agglomeration intensity in the SARA fractions was reduced to different degrees. Due to the aging of asphalt binder, asphaltenes formed different types of micro-stacking phenomena such as “T-shaped stacking,” “Face to Face stacking,” and “Offset Face to Face stacking.” The bio-rejuvenators of BR-1 and BR-5 exerted different regenerative effects during the diffusion process of aged asphalt binder. For BR-1, the “Pull-Out” and “Intercalation” effect can be observed in the process of asphaltene deagglomeration. “Pull-Out” is the main regenerative effect of BR-5 in aged asphalt binder. A strong electrostatic interaction occurs between BR-5 and PAHs in asphaltenes. Thus, BR-5 achieves the goal of aged asphalt binder regeneration by attracting PAHs.","Aged asphalt binder; Bio-rejuvenators; Diffusion mechanism; Microstructure morphology; Molecular dynamics simulation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-11-25","","","Pavement Engineering","","",""
"uuid:a063b6d7-71fc-4b2b-b65b-2c374e52dd8a","http://resolver.tudelft.nl/uuid:a063b6d7-71fc-4b2b-b65b-2c374e52dd8a","Know-me: A toolkit for designing personalised dementia care","Wang, G. (TU Delft Applied Ergonomics and Design); Albayrak, A. (TU Delft Applied Ergonomics and Design); Hogervorst, Eef (Loughborough University); van der Cammen, T.J.M. (TU Delft Applied Ergonomics and Design)","","2021","Personalisation is a crucial element in providing person-centred care for people with de-mentia. This paper presents the development and evaluation of a design toolkit to facilitate the work of designers and healthcare professionals in personalising dementia care. This toolkit, named “Know-me”, was grounded in the findings of Ergonomics in Aging, Co-design, and Data-enabled Design, derived from literature review and from the field during a four-year doctorate project. “Know-me” was designed to be easily accessible, flexible, and engaging, providing concrete and hands-on guidance for designers and healthcare professionals to use in designing for personalised dementia care. A proof-of-concept evaluation of the “Know-me” toolkit was conducted via student projects on design for dementia care. During this process, we found that “Know-me” could be adapted flexibly so that the care team could use some of the tools by themselves. A feature-by-feature comparison of the “Know-me” toolkit with similar state-of-the-art toolkits was conducted, and based upon this, the strengths and weaknesses of the “Know-me” toolkit are discussed. This preliminary study indicates that the “Know-me” toolkit is a helpful addition to the current pool of toolkits on designing for dementia care.","Co-design; Data-enabled design; Dementia; Design education; Design tool; Ergonomics; Human-centred design; Nursing homes; Personalised dementia care","en","journal article","","","","","","","","","","","Applied Ergonomics and Design","","",""
"uuid:8abdbcdc-eb51-43f7-b5db-5a8169d7bdfa","http://resolver.tudelft.nl/uuid:8abdbcdc-eb51-43f7-b5db-5a8169d7bdfa","Accretion-erosion conversion in the subaqueous Yangtze Delta in response to fluvial sediment decline","Luan, Hua Long (East China Normal University; Changjiang River Scientific Research Institute (CRSRI)); Ding, Ping Xing (East China Normal University); Yang, Shi Lun (East China Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; East China Normal University; Deltares)","","2021","Identifying the pattern of delta morphological change under decreasing sediment flux due to dam construction is essential for sustainable management in such densely populated coastal areas. In this study, we investigated the morphological processes of the Yangtze mouth bar and prodelta based on bathymetric data on a decadal-interannual scale (1958, 1978, 1997, 2002, 2007, 2010, 2013 and 2015). We found that strong accretion (205.1 Mm3 yr−1) occurred during 1958–1978, when a high sediment load (465 Mt yr−1) was supplied by the Yangtze. Afterwards, the net accumulation rate decreased to 31.9 Mm3 yr−1 in 1978–1997 and 114.6 Mm3 yr−1 in 1997–2002 as a result of riverine sediment loads decreasing to 390 Mt yr−1 and 314 Mt yr−1, respectively. Surprisingly, the net accumulation rate increased to 130.8 Mm3 yr−1 in 2002–2007, though the sediment load sharply decreased to 177 Mt yr−1. This anomaly was attributed to the construction of training walls within the mouth bar area, which induced significant accretion in groyne-sheltered areas and nearby regions. Along with a further decrease in sediment load, the entire study area converted to net erosion of −200.4 Mm3 yr−1 in 2007–2010 and −152.2 Mm3 yr−1 in 2010–2013. Stronger erosion in the former period was partly caused by intensive dredging activities in the mouth bar area. The critical sediment discharge for the Yangtze mouth bar and prodelta to retain net accretion was estimated to be ca. 218 Mt yr−1. If deducting the impacts of estuarine engineering projects on accretion/erosion during 1997–2010, the critical sediment discharge is adjusted to ca. 234 Mt yr−1. In combination with previously reported accretion-erosion conversion elsewhere in the Yangtze Delta, we inferred that most portion of the subaqueous delta has most likely converted from net accretion to net erosion in response to fluvial sediment decline, and the mouth bar area showed the latest conversion among portions of the delta. Integrated assessment and adaptive strategies are urgently required for the Yangtze Delta to survive the coming erosional stage.","Accretion-erosion conversion; Estuarine engineering projects; Fluvial sediment decline; Yangtze Delta","en","journal article","","","","","","Accepted author manuscript","","2023-03-13","","","Coastal Engineering","","",""
"uuid:15743967-de12-4544-a8c1-ad25b9001ca1","http://resolver.tudelft.nl/uuid:15743967-de12-4544-a8c1-ad25b9001ca1","Perovskite solar cells with embedded homojunction via nonuniform metal ion doping","Lin, Yuze (University of North Carolina); Li, Tao (University of Nebraska–Lincoln); Liu, Ye (University of North Carolina); Bahrami, Behzad (South Dakota State University, Brookings); Guo, Dengyang (TU Delft ChemE/Opto-electronic Materials); Fang, Yanjun (University of Nebraska); Shao, Yuchuan (University of North Carolina); Wang, Qi (University of North Carolina); Savenije, T.J. (TU Delft ChemE/Opto-electronic Materials)","","2021","A long photoluminescence decay lifetime has been regarded as a generic indication of long charge carrier recombination lifetime in semiconductors such as metal halide perovskites (MHPs), which have shown tremendous success in solar cells. Here, we report that MHP polycrystalline films with extrinsic metal ions have a very long charge recombination lifetime, but a much shorter photoluminescence decay lifetime, and this huge difference can be explained by a model of lateral homojunction within each individual grain. The lateral homojunction is formed due to the doping along grain boundaries by metal ions, and then verified by nanoscale potential mapping and transient photo-response mapping. The built-in electric field within each grain reduces the recombination of free charge carriers within the perovskite grain and along grain boundaries, while the free electrons and holes are collected to cathode and anode through the grain boundaries and grain interiors, respectively. Then, the efficiencies of MHP polycrystalline solar cells are increased.","charge carrier recombination; grain boundary doping; lateral homojunction; metal ion; nonuniform doping; perovskite solar cell","en","journal article","","","","","","","","","","","ChemE/Opto-electronic Materials","","",""
"uuid:f45c053e-f200-4d7b-bf12-e966bb86c3e6","http://resolver.tudelft.nl/uuid:f45c053e-f200-4d7b-bf12-e966bb86c3e6","Fed-Batch Droplet Nanobioreactor for Controlled Growth of Cyberlindnera (Pichia) jadinii: A Proof-Of-Concept Demonstration","Totlani, K. (TU Delft ChemE/Product and Process Engineering); Wang, Yen Chieh (Student TU Delft); Bisschops, Maxime (Student TU Delft); de Riese, Thorben (External organisation); Kreutzer, M.T. (TU Delft Universitaire Faciliteiten; TU Delft ChemE/Afdelingsbureau); van Gulik, W.M. (TU Delft BT/Industriele Microbiologie); van Steijn, V. (TU Delft ChemE/Product and Process Engineering)","","2021","A key bottleneck in bioprocess development is that state-of-the-art tools used for screening of cells and optimization of cultivation conditions do not represent the conditions enforced at industrial scale. At industrial scale, cell growth is strictly controlled (“fed-batch”) to optimize the metabolites produced by the cells. In contrast, cell growth is uncontrolled (“batch”) in microwells commonly used for bioprocess development due to the difficulty to continuously supply minute amounts of nutrients to the cells in these wells over the course of the cultivation experiment. This work addresses this bottleneck through the development of a droplet-based fed-batch nanobioreactor. A key challenge addressed in this work is the implementation of the required non-steady droplet operations on chip to establish a semi-continuous nutrient supply, while keeping the chip and its operation as simple as possible. The ability to study micro-organisms under nutrient-controlled fed-batch conditions is demonstrated using the yeast Cyberlindnera (Pichia) jadinii, with the cell growth rate controlled through the glucose concentration. Given the relative ease of operation and the potential to extend its features, the presented nanobioreactor provides a solid platform technology for further development and use in the field of bioprocess development and beyond.","droplet microfluidics; fed-batch; lab-on-a-chip; yeast","en","journal article","","","","","","","","","","","ChemE/Product and Process Engineering","","",""
"uuid:19121e73-9ea1-4f23-b4e2-d95939219276","http://resolver.tudelft.nl/uuid:19121e73-9ea1-4f23-b4e2-d95939219276","Numerical study of a turbulent co-axial non-premixed flame for methanol hydrothermal combustion: Comparison of the EDC and FGM models","Ren, Mengmeng (Xi'an University of Architecture and Technology); Wang, Shuzhong (Xi’an Jiaotong University); Romero-Anton, N. (University of the Basque Country); Zhao, Junxue (Xi'an University of Architecture and Technology); Zou, Chong (Xi'an University of Architecture and Technology); Roekaerts, D.J.E.M. (TU Delft Fluid Mechanics)","","2021","Eddy dissipation concept (EDC) model and flamelet generated manifolds (FGM) model are developed separately to study the temperature profiles and extinction limits of non-premixed hydrothermal flames. Predictions by the two models are evaluated comparatively by experimental data in literatures. FGM model shows relatively better prediction of temperature than EDC model in the near nozzle field. Extinction temperatures can be predicted by EDC model with deviations of 10–33 K. The extinction flow rates predicted by the FGM model are higher than those by the EDC model. Flow fields and reaction source terms are analysed to identify the inherent mechanism leading different results by the two models. It is illustrated that the positive effect of turbulence on reaction rate near the nozzle by the FGM model is the essential reason causing different flame characteristics from the EDC model by which the turbulence only has negative effect on reaction rate.","Eddy dissipation concept (EDC) model; Extinction limits; Flame temperature profile; Flamelet generated manifolds (FGM) model; Hydrothermal combustion; Turbulence-chemistry interaction","en","journal article","","","","","","Accepted Author Manuscript","","2022-12-15","","","Fluid Mechanics","","",""
"uuid:8c46bc53-d826-4d04-80fd-ea2a722736fb","http://resolver.tudelft.nl/uuid:8c46bc53-d826-4d04-80fd-ea2a722736fb","Regime shifts in the Changjiang (Yangtze River) Estuary: The role of concentrated benthic suspensions","Lin, J. (TU Delft Coastal Engineering; East China Normal University); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Guo, Leicheng (East China Normal University); Zhu, C. (TU Delft Coastal Engineering; East China Normal University); He, Qing (East China Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; East China Normal University; Deltares)","","2021","Channel deepening often triggers positive feedback between tidal deformation, sediment import and drag reduction, which leads to the regime shift in estuaries from low-turbid to hyper-turbid state. In this study, a transition in profiles of suspended sediment concentration (SSC) is hypothesised by including a positive feedback loop of vertical mixing and settling. Such a hypothesis is validated by the historical observations in the North Passage of Changjiang (Yangtze River) Estuary, with decreasing SSC in mid-lower layers and increasing SSC near the bed after the deepening. A mobile pool of concentrated benthic suspensions (CBS) develops in the North Passage, with a tidally averaged length of ~20 km and a mean thickness of ~4 m. The width of the CBS pool is limited (<1 km) as the CBS is concentrated in the Deepwater Navigational Channel. The movements of the CBS pool, combined with tidal asymmetry (e.g., slack-water asymmetry and lateral flow asymmetry), results in sediment trapping in the middle reaches and on the south flank of the channel. Observations by a bottom tripod system show the response of friction/drag coefficient to sediment concentration: (1) nearly linear decrease within low SSC (<10 kg/m3); (2) constant and minimum coefficient (with drag reduction up to 60–80%) in the presence of CBS (10–80 kg/m3). An empirical relationship was derived, which can be used to predict the friction coefficient and the magnitude of drag reduction for sediment transport studies, particularly for modelling regime shifts in estuaries.","Channel deepening; Concentrated benthic suspensions; Drag reduction; Estuarine turbidity maximum; Sediment trapping; Turbulence damping","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-07-02","","","Coastal Engineering","","",""
"uuid:5d5e014e-f483-481b-98c3-33cb95733638","http://resolver.tudelft.nl/uuid:5d5e014e-f483-481b-98c3-33cb95733638","Synthesis and Structure-Property Relationships of Polyimide Covalent Organic Frameworks for Carbon Dioxide Capture and (Aqueous) Sodium-Ion Batteries","van der Jagt, R. (TU Delft RST/Storage of Electrochemical Energy); Vasileiadis, A. (TU Delft RST/Storage of Electrochemical Energy); Veldhuizen, H.V. (TU Delft Novel Aerospace Materials); Ganapathy, S. (TU Delft RST/Storage of Electrochemical Energy; TU Delft RID/TS/Instrumenten groep); Habisreutinger, N.C.P. (TU Delft Novel Aerospace Materials); van der Veen, M.A. (TU Delft ChemE/Catalysis Engineering); Wang, C. (TU Delft RST/Storage of Electrochemical Energy); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy); van der Zwaag, S. (TU Delft Novel Aerospace Materials); Nagai, A. (TU Delft Novel Aerospace Materials)","","2021","Covalent organic frameworks (COFs) are an emerging material family having several potential applications. Their porous framework and redox-active centers enable gas/ion adsorption, allowing them to function as safe, cheap, and tunable electrode materials in next-generation batteries, as well as CO2 adsorption materials for carbon-capture applications. Herein, we develop four polyimide COFs by combining aromatic triamines with aromatic dianhydrides and provide detailed structural and electrochemical characterization. Through density functional theory (DFT) calculations and powder X-ray diffraction, we achieve a detailed structural characterization, where DFT calculations reveal that the imide bonds prefer to form at an angle with one another, breaking the 2D symmetry, which shrinks the pore width and elongates the pore walls. The eclipsed perpendicular stacking is preferable, while sliding of the COF sheets is energetically accessible in a relatively flat energy landscape with a few metastable regions. We investigate the potential use of these COFs in CO2 adsorption and electrochemical applications. The adsorption and electrochemical properties are related to the structural and chemical characteristics of each COF, giving new insights for advanced material designs. For CO2 adsorption specifically, the two best performing COFs originated from the same triamine building block, which-in combination with force-field calculations-revealed unexpected structure-property relationships. Specific geometries provide a useful framework for Na-ion intercalation with retainable capacities and stable cycle life at a relatively high working potential (>1.5 V vs Na/Na+). Although this capacity is low compared to conventional inorganic Li-ion materials, we show as a proof of principle that these COFs are especially promising for sustainable, safe, and stable Na-aqueous batteries due to the combination of their working potentials and their insoluble nature in water.","","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:53e7697a-e379-484f-9c58-ddaf43a459ce","http://resolver.tudelft.nl/uuid:53e7697a-e379-484f-9c58-ddaf43a459ce","Dual-action self-healing protective coatings with photothermal responsive corrosion inhibitor nanocontainers","Ma, Lingwei (University of Science and Technology Beijing; Luoyang Ship Material Research Institute); Wang, Jinke (University of Science and Technology Beijing); Zhang, D. (University of Science and Technology Beijing); Huang, Yao (University of Science and Technology Beijing); Huang, Luyao (University of Science and Technology Beijing); Wang, Panjun (University of Science and Technology Beijing); Qian, Hongchang (University of Science and Technology Beijing); Li, Xiaogang (University of Science and Technology Beijing); Terryn, H.A. (TU Delft Team Arjan Mol; Vrije Universiteit Brussel); Mol, J.M.C. (TU Delft Team Arjan Mol)","","2021","This work introduces a novel nanocomposite coating with dual-action self-healing corrosion protection activated by the photothermal response of plasmonic titanium nitride nanoparticles (TiN NPs). TiN@mesoporous SiO2 core–shell nanocontainers were developed as reservoirs for benzotriazole (BTA) corrosion inhibitors and incorporated into the shape memory epoxy coating matrix. Under near-infrared (NIR) light irradiation, the thermogenesis effect of TiN could not only promote the release of corrosion inhibitors from nanocontainers into the crevice, but also trigger the shape memory effect of damaged epoxy to merge the coating scratch. As such, the dual-action self-healing mechanisms combining the formation of an inhibitor-based protective layer and the scratch closure efficiently suppressed the corrosion process at the exposed metal surface. Surface characterization and electrochemical measurement results proved that the nanocomposite coating incorporated with 2 wt% of TiN-BTA@SiO2 exhibited the optimal corrosion protection as well as an excellent self-healing performance that can be initiated within 30 s of NIR illumination. This photo-controlled self-healing approach is potentially useful in designing next-generation self-healing coatings with ultrafast response time and high healing efficiency.","Corrosion inhibitor; Photothermal response; Plasmonic titanium nitride; Self-healing coating; Shape memory polymer","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-03-24","","","Team Arjan Mol","","",""
"uuid:5a772bd5-bedb-4081-a68a-fc7f61b7c849","http://resolver.tudelft.nl/uuid:5a772bd5-bedb-4081-a68a-fc7f61b7c849","Degradation behaviors and in-vivo biocompatibility of a rare earth- and aluminum-free magnesium-based stent","Bian, Dong (Guangdong Academy of Medical Sciences); Zhou, Xiaochen (Peking University); Liu, Jianing (Peking University); Li, Wenting (Peking University); Shen, Danni (Peking University); Zheng, Yufeng (Peking University; Guangdong Academy of Medical Sciences); Gu, Wenda (Guangdong Academy of Medical Sciences); Jiang, Jingjun (Peking University People’s Hospital); Li, Mei (Guangdong Academy of Medical Sciences); Chu, Xiao (Guangdong Academy of Medical Sciences); Ma, Limin (Guangdong Academy of Medical Sciences); Wang, Xiaolan (Guangdong Academy of Medical Sciences); Zhang, Yu (Guangdong Academy of Medical Sciences); Leeflang, M.A. (TU Delft Biomaterials & Tissue Biomechanics); Zhou, J. (TU Delft Biomaterials & Tissue Biomechanics)","","2021","Biodegradable stents can provide scaffolding and anti-restenosis benefits in the short term and then gradually disappear over time to free the vessel, among which the Mg-based biodegradable metal stents have been prosperously developed. In the present study, a Mg-8.5Li (wt.%) alloy (RE- and Al-free) with high ductility (> 40%) was processed into mini-tubes, and further fabricated into finished stent through laser cutting and electropolishing. In-vitro degradation test was performed to evaluate the durability of this stent before and after balloon dilation. The influence of plastic deformation and residual stress (derived from the dilation process) on the degradation was checked with the assistance of finite element analysis. In addition, in-vivo degradation behaviors and biocompatibility of the stent were evaluated by performing implantation in iliac artery of minipigs. The balloon dilation process did not lead to deteriorated degradation, and this stent exhibited a decent degradation rate (0.15 mm/y) in vitro, but divergent result (> 0.6 mm/y) was found in vivo. The stent was almost completely degraded in 3 months, revealing an insufficient scaffolding time. Meanwhile, it did not induce possible thrombus, and it was tolerable by surrounding tissues in pigs. Besides, endothelial coverage in 1 month was achieved even under the severe degradation condition. In the end, the feasibility of this stent for treatment of benign vascular stenosis was generally discussed, and perspectives on future improvement of Mg-Li-based stents were proposed.","Biocompatibility; Biodegradable stent; Degradation behavior; Iliac artery; Mg-Li alloy","en","journal article","","","","","","Accepted Author Manuscript","","2023-03-20","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:ef52ab26-2cfb-4299-a86a-e79f90a5bad2","http://resolver.tudelft.nl/uuid:ef52ab26-2cfb-4299-a86a-e79f90a5bad2","Shear-slip behaviour of prefabricated composite shear stud connectors in composite bridges","Gao, Yanmei (Chongqing Jiaotong University); Li, Chengjun (Sichuan Vocational and Technical College of Communications); Wang, Xuefei (Chongqing Jiaotong University); Zhou, Zhixiang (Shenzhen University); Fan, Liang (Chongqing Jiaotong University); Heng, J. (TU Delft Steel & Composite Structures; Shenzhen University)","","2021","This paper has investigated the shear-slip behaviour of an innovative prefabricated composite shear stud (PCSS) connector and its application in the prefabricated steel–concrete composite bridges. A series of push-out tests are carried out on a total of 12 specimens, including 6 PCSS specimens and 6 conventional shear stud (CSS) specimens. Further comparison has been carried out between the test result and the data available from the literature. Based on the test, a high-resolution finite element (FE) analysis has been performed to reveal the load transfer mechanism of the PCSS connector at the component-level. After that, an advanced FE model has been established and validated by a full-scale test of the prefabricated composite bridge using the PCSS. With the FE model, the load-slip behaviour and slip distribution are investigated in details. The result highlights the enhanced shear capacity and ductility of the PCSS specimens compared with the CSS specimens, as well as the feasibility of PCSS connectors in composite bridges. Meanwhile, it is further revealed by the detailed investigation that the enhancement could be attributed to the lateral constraint on the concrete by the vertical steel plate in the PCSS. Besides, it is also found that the load-slip behaviour of composite bridges using the PCSS is influenced by the cracking at the seam between deck blocks. Consequently, abrupt changes can be found in the load-slip curve once the cracking occurs, which differs from the traditional composite bridges.","High-resolution finite element analysis; Load-transfer mechanism; Prefabricated composite shear studs connector; Prefabricated steel–concrete composite bridge; Push-out test; Shear-slip behaviour","en","journal article","","","","","","Accepted Author Manuscript","","2023-05-04","","","Steel & Composite Structures","","",""
"uuid:e2eb0e3f-899b-42b2-b13f-aa6bd3b3bce5","http://resolver.tudelft.nl/uuid:e2eb0e3f-899b-42b2-b13f-aa6bd3b3bce5","Synchronized high-resolution bed-level change and biophysical data from 10 marsh-mudflat sites in northwestern Europe","Hu, Zhan (Sun Yat-sen University; Southern Marine Science and Engineering Guangdong Laboratory); Willemsen, Pim W.J.M. (University of Twente; Universiteit Utrecht); Borsje, Bas W. (University of Twente); Wang, Chen (Satellite Application Center for Ecology and Environment); Wang, Heng (Southern Marine Science and Engineering Guangdong Laboratory; Sun Yat-sen University); Van Der Wal, Daphne (University of Twente; NIOZ Royal Netherlands Institute for Sea Research); Zhu, Zhenchang (Guangdong University of Technology); Vuik, V. (TU Delft Coastal Engineering; HKV Consultants); Bouma, Tjeerd J. (NIOZ Royal Netherlands Institute for Sea Research; Universiteit Utrecht)","","2021","Tidal flats provide valuable ecosystem services such as flood protection and carbon sequestration. Erosion and accretion processes govern the ecogeomorphic evolution of intertidal ecosystems (marshes and bare flats) and, hence, substantially affect their valuable ecosystem services. To understand the intertidal ecosystem development, high-frequency bed-level change data are thus needed. However, such datasets are scarce due to the lack of suitable methods that do not involve excessive labour and/or costly instruments. By applying newly developed surface elevation dynamics (SED) sensors, we obtained unique high-resolution daily bed-level change datasets in the period 2013-2017 from 10 marsh-mudflat sites situated in the Netherlands, Belgium, and the United Kingdom in contrasting physical and biological settings. At each site, multiple sensors were deployed for 9-20 months to ensure sufficient spatial and temporal coverage of highly variable bed-level change processes. The bed-level change data are provided with synchronized hydrodynamic data, i.e. water level, wave height, tidal current velocity, medium sediment grain size (D50), and chlorophyll a level at four sites. This dataset has revealed diverse spatial morphodynamics patterns over daily to seasonal scales, which are valuable to theoretical and model development. On the daily scale, this dataset is particularly instructive, as it includes a number of storm events, the response to which can be detected in the bed-level change observations. Such data are rare but useful to study tidal flat response to highly energetic conditions. The dataset is available from 4TU.ResearchData (https://doi.org/10.4121/12693254.v4; Hu et al., 2020), which is expected to expand with additional SED sensor data from ongoing and planned surveys.","","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:cfe09d4c-4486-4656-9fdd-497130378e1b","http://resolver.tudelft.nl/uuid:cfe09d4c-4486-4656-9fdd-497130378e1b","Multi-scale Inequality and Segregation: Theory and Estimation","Owen, Gwilym (University of Sheffield); Manley, D.J. (TU Delft Urban Studies; University of Bristol); Johnston, Ron (University of Bristol); Birabi, Tim (University of Sheffield); Song, Hui (Hebei Institute of Statistical Science, Hebei); Wang, Bifeng (Ningbo University of Technology, Zhejiang)","Pryce, G. (editor)","2021","This chapter explores multi-scale estimation methods as an important future direction for segregation research in China. We explain how these recently developed methods help address many longstanding problems in traditional index-based segregation research and open up new avenues of research on Chinese cities. We explain the conceptual framework underpinning multilevel analysis in the form of a series of propositions that capture the theoretical basis and outline why a multilevel approach to segregation is advantageous. We then illustrate how this approach can be applied to China using census data on Shijiazhuang, the capital city of Hebei Province. We use the model to consider segregation of different ethnic groups and of migrants versus non-migrants. We conclude with a discussion of our findings and our thoughts on future directions for research and the implications for policy.","Index of dissimilarity; Intersectionality; Multilevel segregation; Segregation measurement; Segregation theory; Shijiazhuang, China","en","book chapter","Springer","","","","","","","","","","Urban Studies","","",""
"uuid:bc630552-8061-47d7-b87b-ded59fcf3834","http://resolver.tudelft.nl/uuid:bc630552-8061-47d7-b87b-ded59fcf3834","Suppressing Epidemic Spreading via Contact Blocking in Temporal Networks","Zhao, Xunyi (Student TU Delft); Wang, H. (TU Delft Multimedia Computing)","Benito, Rosa M. (editor); Cherifi, Chantal (editor); Cherifi, Hocine (editor); Moro, Esteban (editor); Rocha, Luis Mateus (editor); Sales-Pardo, Marta (editor)","2021","In this paper, we aim to effectively suppress the spread of epidemic/information via blocking/removing a given fraction of the contacts in a temporal (time evolving) human contact network. We consider the SI (Susceptible- Infected) spreading process, on a temporal contact network to illustrate our methodology: an infected node infects a susceptible node with a probability β when a contact happens between the two nodes. We address the question: which contacts should be blocked in order to minimize the average prevalence over time. We firstly propose systematically a set of link properties (centrality metrics) based on the aggregated network of a temporal network, that captures the number of contacts between each node pair. Furthermore, we define the probability that a contact c(i, j, t) is removed as a function of the centrality of the corresponding link l(i, j) in the aggregated network as well as the time t of the contact. Each of the centrality metrics proposed can be thus regarded as a contact removal strategy. Empirical results on six temporal contact networks show that the epidemic can be better suppressed if contacts between node pairs that have fewer contacts are more likely to be removed and if contacts happened earlier are likely removed. A strategy tends to perform better when the average number contacts removed per node pair has a lower variance. Strategies that lead to a lower largest eigenvalue of the aggregated network after contact removal do not mitigate the spreading better. This contradicts the finding in static networks, that a network with a small largest eigenvalue tends to be robust against epidemic spreading, illustrating the complexity introduced by the underlying temporal networks.","Epidemic mitigation; SI spreading; Temporal network","en","conference paper","Springer","","","","","Accepted author manuscript","","2021-12-20","","","Multimedia Computing","","",""
"uuid:e356cec2-10a7-4153-ba8f-c6d3423110b8","http://resolver.tudelft.nl/uuid:e356cec2-10a7-4153-ba8f-c6d3423110b8","Memory-Efficient Modeling and Slicing of Large-Scale Adaptive Lattice Structures","Liu, Shengjun (Central South University China); Liu, Tao (Central South University); Zou, Qiang (The University of Manchester); Wang, W. (TU Delft Materials and Manufacturing; Dalian University); Doubrovski, E.L. (TU Delft Mechatronic Design); Wang, Charlie C.L. (The University of Manchester)","","2021","Lattice structures have been widely used in various applications of additive manufacturing due to its superior physical properties. If modeled by triangular meshes, a lattice structure with huge number of struts would consume massive memory. This hinders the use of lattice structures in large-scale applications (e.g., to design the interior structure of a solid with spatially graded material properties). To solve this issue, we propose a memory-efficient method for the modeling and slicing of adaptive lattice structures. A lattice structure is represented by a weighted graph where the edge weights store the struts' radii. When slicing the structure, its solid model is locally evaluated through convolution surfaces in a streaming manner. As such, only limited memory is needed to generate the toolpaths of fabrication. Also, the use of convolution surfaces leads to natural blending at intersections of struts, which can avoid the stress concentration at these regions. We also present a computational framework for optimizing supporting structures and adapting lattice structures with prescribed density distributions. The presented methods have been validated by a series of case studies with large number (up to 100 M) of struts to demonstrate its applicability to large-scale lattice structures.","","en","journal article","","","","","","Accepted Author Manuscript","","","","","Materials and Manufacturing","","",""
"uuid:61de8af3-5944-4552-b26b-98b3c5868016","http://resolver.tudelft.nl/uuid:61de8af3-5944-4552-b26b-98b3c5868016","Knitting 4D garments with elasticity controlled for body motion","Liu, Z. (TU Delft Materials and Manufacturing; Centre for Perceptual and Interactive Intelligence Limited, Hong Kong); Han, Xingjian (Boston University); Zhang, Yuchen (Centre for Perceptual and Interactive Intelligence Limited, Hong Kong); Chen, Xiangjia (Centre for Perceptual and Interactive Intelligence Limited, Hong Kong); Lai, Y. (Cardiff University); Doubrovski, E.L. (TU Delft Mechatronic Design); Whiting, Emily (Boston University); Wang, C.C. (The University of Manchester)","","2021","In this paper, we present a new computational pipeline for designing and fabricating 4D garments as knitwear that considers comfort during body movement. This is achieved by careful control of elasticity distribution to reduce uncomfortable pressure and unwanted sliding caused by body motion. We exploit the ability to knit patterns in different elastic levels by single-jersey jacquard (SJJ) with two yarns. We design the distribution of elasticity for a garment by physics-based computation, the optimized elasticity on the garment is then converted into instructions for a digital knitting machine by two algorithms proposed in this paper. Specifically, a graph-based algorithm is proposed to generate knittable stitch meshes that can accurately capture the 3D shape of a garment, and a tiling algorithm is employed to assign SJJ patterns on the stitch mesh to realize the designed distribution of elasticity. The effectiveness of our approach is verified on simulation results and on specimens physically fabricated by knitting machines.","4D garment; computational fabrication; elasticity control; knitting","en","journal article","","","","","","Accepted Author Manuscript","","","","","Materials and Manufacturing","","",""
"uuid:914070cb-d4fe-4bad-8064-bc83154b895b","http://resolver.tudelft.nl/uuid:914070cb-d4fe-4bad-8064-bc83154b895b","Synthesizing Spoken Descriptions of Images","Wang, X. (TU Delft Multimedia Computing; Xi’an Jiaotong University); van der Hout, Justin (Student TU Delft); Zhu, Jihua (Xi’an Jiaotong University); Hasegawa-Johnson, Mark (University of Illinois at Urbana-Champaign); Scharenborg, O.E. (TU Delft Multimedia Computing)","","2021","Image captioning technology has great potential in many scenarios. However, current text-based image captioning methods cannot be applied to approximately half of the world's languages due to these languages’ lack of a written form. To solve this problem, recently the image-to-speech task was proposed, which generates spoken descriptions of images bypassing any text via an intermediate representation consisting of phonemes (image-to-phoneme). Here, we present a comprehensive study on the image-to-speech task in which, 1) several representative image-to-text generation methods are implemented for the image-to-phoneme task, 2) objective metrics are sought to evaluate the image-to-phoneme task, and 3) an end-to-end image-to-speech model that is able to synthesize spoken descriptions of images bypassing both text and phonemes is proposed. Extensive experiments are conducted on the public benchmark database Flickr8k. Results of our experiments demonstrate that 1) State-of-the-art image-to-text models can perform well on the image-to-phoneme task, and 2) several evaluation metrics, including BLEU3, BLEU4, BLEU5, and ROUGE-L can be used to evaluate image-to-phoneme performance. Finally, 3) end-to-end image-to-speech bypassing text and phonemes is feasible.","Speech processing; Image-to-speech generation; multimodal modelling; speech synthesis; cross-modal captioning","en","journal article","","","","","","Accepted author manuscript","","","","","Multimedia Computing","","",""
"uuid:9b8c3af0-8144-4889-942d-e6919dfe060a","http://resolver.tudelft.nl/uuid:9b8c3af0-8144-4889-942d-e6919dfe060a","Direction of Arrival Estimation of Wideband Sources Using Sparse Linear Arrays","Wang, F. (TU Delft Signal Processing Systems); Tian, Zhi (George Mason University); Leus, G.J.T. (TU Delft Signal Processing Systems); Fang, Jun (University of Electronic Science and Technology of China)","","2021","In this paper, we study the problem of wideband direction of arrival (DoA) estimation with sparse linear arrays (SLAs), where a number of uncorrelated wideband signals impinge on an SLA and the data is collected from multiple frequency bins. To boost the performance and perform underdetermined DoA estimation, the difference co-array response matrices for all frequency bins are constructed first. Then, to merge the data from different frequency bins, we resort to the Jacobi-Anger approximation to transform the co-array response matrices of all frequency bins into a single virtual uniform linear array (ULA) response matrix. The major advantage of this approach is that the transformation matrices are all signal independent. For the special case where all sources share an identical distribution of the power spectrum, we develop two super-resolution off-the-grid DoA estimation approaches based on atomic norm minimization (ANM), one with and one without prior knowledge of the power spectrum. Our solution is able to resolve more sources than the number of antennas but also more than the number of degrees of freedom (DoF) of the difference co-array of the SLA. For the general case where each source has an arbitrary power spectrum, we propose a multi-task ANM method to exploit the joint sparsity from all frequency bins. Simulation results show that our proposed methods present a clear performance advantage over existing methods, and achieve an estimation accuracy close to the associated Cramér-Rao bounds (CRBs).","Wideband direction-of-arrival (DoA) estimation; sparse linear array (SLA); Jacobi-Anger approximation; atomic norm minimization (ANM)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-07","","","Signal Processing Systems","","",""
"uuid:77d7e22a-8c4d-4e33-8d94-2355549a4625","http://resolver.tudelft.nl/uuid:77d7e22a-8c4d-4e33-8d94-2355549a4625","Reliability-based buckling optimization with an accelerated Kriging metamodel for filament-wound variable angle tow composite cylinders","Wang, Z. (TU Delft Aerospace Structures & Computational Mechanics; University of Electronic Science and Technology of China); Almeida, José Humberto S. (Aalto University); St-Pierre, Luc (Aalto University); Wang, Zhonglai (University of Electronic Science and Technology of China); Castro, Saullo G.P. (TU Delft Aerospace Structures & Computational Mechanics)","","2020","A reliability-based optimization framework is introduced and used to design filament-wound cylindrical shells with variable angle tow. Seven design cases are investigated to enable a comparison between constant-stiffness and variable angle tow designs, also considering effects of thickness variation created due to overlapping tow paths, determined using the kinematics of the filament winding manufacturing process. The uncertainty in the winding angle is considered in the optimization by means of metamodels constructed using the Kriging method. Moving search windows are incorporated into the Kriging metamodel to accelerate its convergence by reducing the number of training iterations. The results prove the efficacy of the proposed framework and clearly demonstrate the advantage of variable-stiffness designs over conventional ones for achieving a maximum load carrying capacity, while keeping the robustness of the design towards manufacturing uncertainties.","Buckling; Filament winding; Kriging; Metamodeling; Reliability-based optimization; Uncertainty quantification","en","journal article","","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:3e8c514c-5f00-4258-8c01-99a216bd4b02","http://resolver.tudelft.nl/uuid:3e8c514c-5f00-4258-8c01-99a216bd4b02","Interaction characteristics between multi-port hybrid DC circuit breaker and MVDC distribution system under diversified working conditions","Wen, Weijie (China Electric Power Research Institute, Beijing; Tianjin University); Li, Pengyu (Tianjin University); Cao, Hong (China Electric Power Research Institute, Beijing); Liu, Haijin (Tianjin University); Wang, Xingguo (China Electric Power Research Institute, Beijing); Lv, Hui (Tianjin University); Li, Bin (Tianjin University); Popov, M. (TU Delft Intelligent Electrical Power Grids)","","2020","Due to the progressive penetration and usage of renewable sources and loads based on power electronics, medium voltage direct current (MVDC) distribution system is getting broad attention. Direct current circuit breakers (DCCBs) are of vital importance for the reliability and flexibility of power system. With features of low cost and micro-operating losses, multi-port hybrid DCCB with negative voltage source (NVS) has been proposed by the authors and might be a better choice. To further promote its industry application in MVDC system, interaction characteristics between DCCB and power system are investigated in this study. The structure of multi-port hybrid DCCB is briefly introduced. Then, considering the diversified working conditions, e.g. single fault, multiple faults and switching load current with random direction, the cooperation sequence of components in multi-port DCCB under all these working conditions is proposed, respectively. Then, based on simulation model established in PSCAD/EMTDC, transient current/voltage distribution pattern inside multi-port DCCB and its mechanism are discussed, and simulation results have verified the superiority and effectiveness of multi-port hybrid DCCB with NVS in MVDC system.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-08-17","","","Intelligent Electrical Power Grids","","",""
"uuid:e975cb1a-13fe-4b79-93c7-18ea03998213","http://resolver.tudelft.nl/uuid:e975cb1a-13fe-4b79-93c7-18ea03998213","Machine learning for the prediction of pseudorealistic pediatric abdominal phantoms for radiation dose reconstruction","Virgolin, M. (Centrum Wiskunde & Informatica (CWI)); Wang, Ziyuan (Amsterdam UMC); Alderliesten, T. (TU Delft Algorithmics; Amsterdam UMC; Vrije Universiteit Amsterdam); Bosman, P.A.N. (TU Delft Algorithmics; Centrum Wiskunde & Informatica (CWI))","","2020","Purpose: Current phantoms used for the dose reconstruction of long-term childhood cancer survivors lack individualization. We design a method to predict highly individualized abdominal three-dimensional (3-D) phantoms automatically. Approach: We train machine learning (ML) models to map (2-D) patient features to 3-D organ-at-risk (OAR) metrics upon a database of 60 pediatric abdominal computed tomographies with liver and spleen segmentations. Next, we use the models in an automatic pipeline that outputs a personalized phantom given the patient's features, by assembling 3-D imaging from the database. A step to improve phantom realism (i.e., avoid OAR overlap) is included. We compare five ML algorithms, in terms of predicting OAR left-right (LR), anterior-posterior (AP), inferior-superior (IS) positions, and surface Dice-Sørensen coefficient (sDSC). Furthermore, two existing human-designed phantom construction criteria and two additional control methods are investigated for comparison. Results: Different ML algorithms result in similar test mean absolute errors: ∼8 mm for liver LR, IS, and spleen AP, IS; ∼5 mm for liver AP and spleen LR; ∼80 % for abdomen sDSC; and ∼60 % to 65% for liver and spleen sDSC. One ML algorithm (GP-GOMEA) significantly performs the best for 6/9 metrics. The control methods and the human-designed criteria in particular perform generally worse, sometimes substantially (+5-mm error for spleen IS,-10 % sDSC for liver). The automatic step to improve realism generally results in limited metric accuracy loss, but fails in one case (out of 60). Conclusion: Our ML-based pipeline leads to phantoms that are significantly and substantially more individualized than currently used human-designed criteria.","dose reconstruction; machine learning; pediatric cancer; phantom; radiation treatment","en","journal article","","","","","","","","","","","Algorithmics","","",""
"uuid:1d032345-5932-497d-ab68-c1f422c12995","http://resolver.tudelft.nl/uuid:1d032345-5932-497d-ab68-c1f422c12995","Autonomous Shipping Systems: Designing for Safety, Control and Responsibility","Wang, X. (TU Delft Ethics & Philosophy of Technology); Cavalcante Siebert, L. (TU Delft Interactive Intelligence); van den Hoven, M.J. (TU Delft Ethics & Philosophy of Technology)","Pelegrin-Borondo, Jorge (editor); Arias-Oliva, Mario (editor); Murata, Kiyoshi (editor); Palma, Maria Lara (editor)","2020","","Autonomous shipping; Value Sensitive Design; safety; control; Responsibility; task ontology","en","conference paper","","","","","","Virtual/online event due to COVID-19","","","","","Ethics & Philosophy of Technology","","",""
"uuid:d78075cb-7614-4248-b3f5-65a5fd4b3586","http://resolver.tudelft.nl/uuid:d78075cb-7614-4248-b3f5-65a5fd4b3586","Multi-pinhole Molecular Breast Tomosynthesis: from Simulation to Prototype","Wang, B. (TU Delft RST/Biomedical Imaging)","Beekman, F.J. (promotor); Goorden, M.C. (promotor); Delft University of Technology (degree granting institution)","2020","Breast cancer, being the most common cancer among females, is nowadays routinely diagnosed using X-ray mammography. Though this technique has proven its effectiveness in many cases, X-ray mammography has some disadvantages like reduced diagnostic sensitivity for dense breasts, need for strong breast compression and inability to assess tissues at the molecular level.
Therefore, there is a need for alternative imaging modalities to improve breast cancer diagnosis. One option is breast scintigraphy, which images the distribution of radiolabelled molecules, called tracers, that concentrate in the tumours in breasts with a planar gamma detector. Different tracers react in different physiological processes with tumours. Therefore imaging a specific tracer can reveal the specific pathological process that is specific for a certain kind of breast tumour. Despite the fact that breast scintigraphy has been reported to have improved diagnostic sensitivity in dense breasts compared to X-ray mammography and does not require strong compression, it offers only 2D images and information on the third dimension is thus lost. In this research we proposed a molecular breast tomosynthesis scanner which provides 3D images of the radiotracers in the breast. In the proposed system, the patient would lie prone on a patient bed with a hole in which the breast is inserted. Subsequently, two gamma cameras equipped with multi-pinhole collimators (therefore the technique is called multi-pinhole molecular breast tomosynthesis, MP-MBT) scan the pendant breast from both sides.
To estimate the performance of MP-MBT, the system was modelled in Monte Carlo simulations in a clinically realistic setting. The results assured us that it was worth building a prototype of MP-MBT to further investigate its imaging capability. Besides, voxelized raytracing (VRT) software developed earlier in our group to accelerate simulations and facilitate system optimisations was validated with the Monte Carlo simulation results. Subsequently, VRT was used in further studies in this project.
The promising results of MP-MBT simulations partly relied on a gamma detector with high spatial linearity over the whole detector surface. However, conventional gamma detectors used in clinical practice have large dead edges, i.e. about 4 cm from the detector edges is unusable, and a detector with small dead edges would be very expensive, which may make MP-MBT a less competitive technology. Therefore, in order to have a gamma detector suitable for MP-MBT, we came up with a few different designs with NaI(Tl) scintillators and photomultiplier tube (PMT) array readouts and evaluated their performances with Monte Carlo simulations. From the simulation results, we eventually chose a design with a staggered layout of 15 square PMTs, among which two PMTs detected the optical photons from the scintillator through extra-long additional light-guides. This gamma detector was built in our lab, and it turned out to have only about 15 mm dead edge (mainly due to the 12 mm sealing).
The customised gamma detector was equipped with a lead multi-pinhole collimator design based on previous research. The whole gamma camera was mounted on a robot arm to create a movable scanner. We calibrated the scanner with a point source and scanned a resolution phantom and a breast phantom to evaluate MP-MBT's performance. In the phantom study, the scanner showed the capability of detecting tumours down to 5 mm when a realistic tracer (technetium sestamibi) concentration was administered.
However, the current prototype is still far from a device that can be used in the clinic and we have found several problems with MP-MBT, especially the noise pattern in the reconstructed images, which should be given special attention in the future research.","pinhole collimator; gamma detector; Monte Carlo simulation; breast imaging; SPECT imaging; molecular imaging","en","doctoral thesis","","9789463662734","","","","","","","","","RST/Biomedical Imaging","","",""
"uuid:eab8dadb-9706-4c55-a065-da75e9e3ab0a","http://resolver.tudelft.nl/uuid:eab8dadb-9706-4c55-a065-da75e9e3ab0a","Graphene Nanoribbon-based Synapses with Versatile Plasticity","Wang, H. (TU Delft Computer Engineering); Cucu Laurenciu, N. (TU Delft Computer Engineering); Jiang, Y. (TU Delft Computer Engineering); Cotofana, S.D. (TU Delft Computer Engineering)","","2020","Designing and implementing artificial systems that can be interfaced with the human brain or that can provide computational ability akin to brain's processing information efficient style is crucial for understanding human brain fundamental operating principles and to unleashing the full potential of brain-inspired computing. As basic neural network components, responsible for information transfer between neurons, artificial synapses able to emulate analog biological synaptic behaviour are of particular interest. State of the art CMOS and memristor-based synapses suffer from scalability drawbacks (large energy consumption and area footprint), variability-induced instability, and are not bio-compatible. In this paper, we propose a generic Graphene Nanoribbon (GNR) based synapse structure and demonstrate that by changing GNR geometry and external bias voltages it can emulate different synaptic plasticity behaviours, i.e., Spike Timing Dependent Plasticity and LongTerm Depression and Potentiation, and that both excitatory and inhibitory synaptic behavior can be obtained with the same GNR geometry. To demonstrate biologically plausible operation, we make use of low voltage bias, i.e., 0.1V, 0.2 V, and consider inputs consistent with measured brain synapses data, i.e.,-50 mV to 50 mV pre-and post-synaptic spikes voltage range, and-60ms to 60 ms time range. The simulations indicate that by changing the GNR shape we can enrich the plasticity behaviour (potentially beyond the considered cases) and the plasticity change of 100% provided by natural synapses can be achieved. Our investigation clearly suggests that the proposed GNR synapse structure is a promising candidate for large-scale neuromorphic systems integration, which might potentially bring novel insight on brain neurophysiology, as it requires a small footprint, is energy effective, biocompatible, and versatile from the synaptic behaviour point of view.","Artificial Synapse; GNR; Graphene; Neuromorphic Computing; STDP","en","conference paper","IEEE","","","","","Accepted author manuscript","","","","","Computer Engineering","","",""
"uuid:4bd9feb9-3185-459f-a480-bace849641de","http://resolver.tudelft.nl/uuid:4bd9feb9-3185-459f-a480-bace849641de","MVMO-Based Identification of Key Input Variables and Design of Decision Trees for Transient Stability Assessment in Power Systems With High Penetration Levels of Wind Power","Wang, D. (TU Delft Mechanical, Maritime and Materials Engineering); Rueda, José L. (TU Delft Intelligent Electrical Power Grids); Rakhshani, E. (TU Delft Intelligent Electrical Power Grids); van der Meijden, M.A.M.M. (TU Delft Intelligent Electrical Power Grids; TenneT TSO B.V.)","","2020","Unlike synchronous generators, wind turbines cannot directly respond to large disturbances, which may cause transient instability, due to their power electronic-based interface and maximum power control strategy. To effectively monitor the influence of wind turbines, this paper proposes an approach that combines decision trees (DTs), and a newly developed variant of the Mean-Variance Mapping Optimization (MVMO) algorithm, to simultaneously tackle the problem of selecting the key variables that properly reflect the transient stability performance of a system dominated by wind power, and designing the DTs for reliable online assessment of transient stability. The notion of key variables refers to the set of variables that are closely related to the modified power system transient stability performance as a consequence of the replacement of conventional power plants by wind generators. The selection of key variables is formulated as a non-linear optimization problem with weight factors as decision variables and is tackled by MVMO. A weight factor is assigned to each key variable candidate, and its value is considered to reflect the degree of influence of the key variable candidate on the splitting property and estimation accuracy of the DTs. The samples of the key variable candidates and the initialized weight factors are used to build the first group of DTs. Then, MVMO iteratively evolves the weight factors according to its special mapping function with minimizing DTs' estimation error. According to the final list of optimized weight factors, system operators can select a reduced set of variables with the largest weight factors as key variables, depending on the resulting accuracy of the DTs. Meanwhile, DTs built by using key variables are considered as the optimal performance trees for transient stability estimation. In this way, the selection of key variables and the development of DTs are made jointly and automatically, without the interference of the users of the DTs. Test results on the modified IEEE 9 bus system and a synthetic model of a real power system show that the proposed method can correctly identify the set of key variables related to wind turbine dynamics, as well as its ability to provide a reliable estimation of the transient stability margin.","decision trees (DTs); massive InteGRATion of power electronic devices (MIGRATE); mean–variance mapping optimization (MVMO); transient stability; wind power","en","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","","Intelligent Electrical Power Grids","","",""
"uuid:7aa643e0-6be4-483a-8bca-98a3deb43c0c","http://resolver.tudelft.nl/uuid:7aa643e0-6be4-483a-8bca-98a3deb43c0c","Review of Packaging Schemes for Power Module","Hou, F. (TU Delft Electronic Components, Technology and Materials; National Center for Advanced Packaging; Chinese Academy of Sciences); Wang, W. (TU Delft DC systems, Energy conversion & Storage; Shenzhen Institute of Wide-bandgap Semiconductors); Cao, Liqiang (National Center for Advanced Packaging; Chinese Academy of Sciences); Li, Jun (National Center for Advanced Packaging; Chinese Academy of Sciences); Su, Meiying (National Center for Advanced Packaging; Chinese Academy of Sciences); Lin, Tingyu (National Center for Advanced Packaging); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Ferreira, Jan Abraham (TU Delft Electrical Sustainable Energy; University of Twente)","","2020","SiC devices are promising for outperforming Si counterparts in high-frequency applications due to its superior material properties. Conventional wirebonded packaging scheme has been one of the most preferred package structures for power modules. However, the technique limits the performance of a SiC power module due to parasitic inductance and heat dissipation issues that are inherent with aluminum wires. In this article, low parasitic inductance and high-efficient cooling interconnection techniques for Si power modules, which are the foundation of packaging methods of SiC ones, are reviewed first. Then, attempts on developing packaging techniques for SiC power modules are thoroughly overviewed. Finally, scientific challenges in the packaging of SiC power module are summarized.","High-efficient cooling; low parasitic inductance; packaging schemes; scientific challenges; SiC power module","en","review","","","","","","","","","","Electrical Sustainable Energy","Electronic Components, Technology and Materials","","",""
"uuid:966eda00-d1ce-47e8-84d7-6604ed7cb714","http://resolver.tudelft.nl/uuid:966eda00-d1ce-47e8-84d7-6604ed7cb714","Fan-Out Panel-Level PCB-Embedded SiC Power MOSFETs Packaging","Hou, F. (TU Delft Electronic Components, Technology and Materials; National Center for Advanced Packaging; Chinese Academy of Sciences); Wang, Qidong (Chinese Academy of Sciences); Chen, Min (Zhejiang University; Chinese Academy of Sciences); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Ferreira, Jan Abraham (University of Twente); Wang, Wenbo (Shenzhen Institute of Wide-bandgap Semiconductors); Ma, R. (National Center for Advanced Packaging; Chinese Academy of Sciences); Su, Meiying (Chinese Academy of Sciences; National Center for Advanced Packaging); Song, Yang (National Center for Advanced Packaging; Chinese Academy of Sciences)","","2020","In this article, a novel fan-out panel-level printed circuit board (PCB)-embedded package for phase-leg silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET) power module is presented. Electro-thermo-mechanical co-design was conducted, and the maximum package parasitic inductance was found to be about 1.24 nH at 100 kHz. Compared with wire-bonded packages, the parasitic inductances of the PCB-embedded package decreased at least by 87.6%. Compared with blind via structure, the thermal resistance of the proposed blind block structure reduced at most by about 26%, and the stress of the SiC MOSFETs decreased by about 45.2%. Then, a novel PCB-embedded packaging process was developed, and three key packaging processes were analyzed. Furthermore, effect of PCB-embedded package on static characterization of SiC MOSFET was analyzed, and it was found that: 1) Output current of PCB-embedded package was decreased under a certain gate-source voltage compared to SiC die; 2) Miller capacitance of SiC MOSFET was increased thanks to parasitic capacitance induced by package; and 3) compared with SiC die, nonflat miller plateau of the PCB-embedded package extends, and as drain-source voltage increases, the nonflat miller plateau extends. Lastly, switching characteristics of the PCB-embedded package and TO-247 package were compared. The results show that the PCB-embedded package has smaller parasitic inductances.","Electro-thermo-mechanical codesign; phase-leg silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET) power module; printed circuit board (PCB)-embedded package; static characterization; switching characterization","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:e4b10719-3e9a-49d9-acce-044e7ee7c863","http://resolver.tudelft.nl/uuid:e4b10719-3e9a-49d9-acce-044e7ee7c863","Bayesian calibration at the urban scale: A case study on a large residential heating demand application in Amsterdam","Wang, C. (Student TU Delft); Tindemans, Simon H. (TU Delft Intelligent Electrical Power Grids); Miller, Clayton (National University of Singapore); Agugiaro, G. (TU Delft Urban Data Science); Stoter, J.E. (TU Delft Urban Data Science)","","2020","A bottom-up building energy modelling at the urban scale based on Geographic Information System and semantic 3D city models can provide quantitative insights to tackle critical urban energy challenges. Nevertheless, incomplete information is a common obstacle to produce reliable modelling results. The residential building heating demand simulation performance gap caused by input uncertainties is discussed in this study. We present a data-driven urban scale energy modelling framework from open-source data harmonization, sensitivity analysis, heating demand simulation at the postcode level to Bayesian calibration with six years of training data and two years of validation data. Comparing the baseline and the calibrated simulation results, the averaged absolute percentage errors of energy use intensity in the study area have significantly improved from 25.0% to 8.3% and from 19.9% to 7.7% in two validation years, while CVRMSE2016=11.5% and CVRMSE2017=13.2%. The overall methodology is extendable to other urban contexts.","Urban building energy modelling; simulation performance gap; geographic information system; sensitivity analysis; Bayesian calibration; spatial-temporal modelling","en","journal article","","","","","","","","","","","Intelligent Electrical Power Grids","","",""
"uuid:b289803d-6b9f-4e7a-b0f7-5720d97cd86c","http://resolver.tudelft.nl/uuid:b289803d-6b9f-4e7a-b0f7-5720d97cd86c","Low-Complexity Equalization of MIMO-OSDM","Han, Jing (Northwestern Polytechnical University); Ma, Shengqian (Northwestern Polytechnical University); Wang, Yujie (Northwestern Polytechnical University); Leus, G.J.T. (TU Delft Signal Processing Systems)","","2020","Orthogonal signal-division multiplexing (OSDM) is an attractive alternative to conventional orthogonal frequency-division multiplexing (OFDM) due to its enhanced ability in peak-to-average power ratio (PAPR) reduction. Combining OSDM with multiple-input multiple-output (MIMO) signaling has the potential to achieve high spectral and power efficiency. However, a direct channel equalization in this case incurs a cubic complexity, which may be expensive for practical use. To solve the problem, low-complexity per-vector and block equalization algorithms of MIMO-OSDM are proposed in this paper for time-invariant and time-varying channels, respectively. By exploiting the channel matrix structures, these algorithms have only a linear complexity in the transformed domain. Simulation results demonstrate their validity and the related performance comparisons.","equalization; inter-vector interference; MIMO; OSDM; underwater acoustic communication","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-06-04","","","Signal Processing Systems","","",""
"uuid:0480bdb8-d4e6-4a55-b1e9-b5d965c0f062","http://resolver.tudelft.nl/uuid:0480bdb8-d4e6-4a55-b1e9-b5d965c0f062","Entropy generation methodology for defect analysis of electronic and mechanical components-A review","Cai, Miao (Guilin University of Electronic Technology); Cui, Peng (Guilin University of Electronic Technology); Qin, Yikang (Guilin University of Electronic Technology); Geng, Daoshuang (Guilin University of Electronic Technology); Wei, Qiqin (Guilin University of Electronic Technology); Wang, Xiyou (Guilin University of Electronic Technology); Yang, Daoguo (Guilin University of Electronic Technology); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials; Guilin University of Electronic Technology)","","2020","Understanding the defect characterization of electronic and mechanical components is a crucial step in diagnosing component lifetime. Technologies for determining reliability, such as thermal modeling, cohesion modeling, statistical distribution, and entropy generation analysis, have been developed widely. Defect analysis based on the irreversibility entropy generation methodology is favorable for electronic and mechanical components because the second law of thermodynamics plays a unique role in the analysis of various damage assessment problems encountered in the engineering field. In recent years, numerical and theoretical studies involving entropy generation methodologies have been carried out to predict and diagnose the lifetime of electronic and mechanical components. This work aimed to review previous defect analysis studies that used entropy generation methodologies for electronic and mechanical components. The methodologies are classified into two categories, namely, damage analysis for electronic devices and defect diagnosis for mechanical components. Entropy generation formulations are also divided into two detailed derivations and are summarized and discussed by combining their applications. This work is expected to clarify the relationship among entropy generation methodologies, and benefit the research and development of reliable engineering components.","Defect; Diagnosis; Electronic and mechanical components; Entropy generation; Methodology; Reliability","en","review","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:7de36fae-025d-499a-a726-21657cffce6c","http://resolver.tudelft.nl/uuid:7de36fae-025d-499a-a726-21657cffce6c","Metal-organic Framework Mediated Electrode Engineering for Electrochemical CO2 Reduction","Wang, R. (TU Delft ChemE/Catalysis Engineering)","Kapteijn, F. (promotor); Gascon, Jorge (promotor); Delft University of Technology (degree granting institution)","2020","The electrochemical conversion of CO2 constitutes an interesting pathway to close the anthropogenic carbon cycles. The ability to reach stable operation in short time makes this method a perfect candidate to buffer the intermittency of renewable power sources, such as solar cells and wind power. As is the case of heterogeneous catalysis, the key to commercialize a process lies in the optimization of the catalytic phase. In this thesis, we take advantage of the unique properties of metal-organic frameworks (MOFs) to synthesize efficient catalysts for electrochemical CO2 reduction (CO2ER). Specifically, the two properties we utilize are the atomic dispersion of the elements and the highly designable building blocks (Chapter 1)....","","en","doctoral thesis","","978-94-028-1858-1","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:55b8f3fc-2e3c-4b76-9ba3-27e287e05a95","http://resolver.tudelft.nl/uuid:55b8f3fc-2e3c-4b76-9ba3-27e287e05a95","Compact Graphene-Based Spiking Neural Network with Unsupervised Learning Capabilities","Wang, He (Student TU Delft); Cucu Laurenciu, N. (TU Delft Computer Engineering); Jiang, Y. (TU Delft Computer Engineering); Cotofana, S.D. (TU Delft Computer Engineering)","","2020","To fully unleash the potential of graphene-based devices for neuromorphic computing, we propose a graphene synapse and a graphene neuron that form together a basic Spiking Neural Network (SNN) unit, which can potentially be utilized to implement complex SNNs. Specifically, the proposed synapse enables two fundamental synaptic functionalities, i.e., Spike-Timing-Dependent Plasticity (STDP) and Long-Term Plasticity, and both Long-Term Potentiation (LTP) and Long-Term Depression (LTD) can be emulated with the same structure by properly adjusting its bias. The proposed neuron captures the essential Leaky Integrate and Fire spiking neuron behavior with post firing refractory interval. We demonstrate the proper operation of the graphene SNN unit by relying on a mixed simulation approach that embeds the high accuracy of atomistic level simulation of graphene structures conductance within the SPICE framework. Subsequently, we analyze the way graphene synaptic plasticity affects the behavior of a 2-layer SNN example consisting of 6 neurons and demonstrate that LTP significantly increases the number of firing events while LTD is diminishing them, as expected. To assess the plausibility of the graphene SNN reaction to input stimuli we simulate its behavior by means of both SPICE and NEST, a well established SNN simulation framework, and demonstrate that the obtained reactions, characterized in terms of total number of firing events and mean Inter-Spike Interval (ISI) length, are in close agreement, which clearly suggests that the proposed design exhibits a proper behavior. Further, we prove the unsupervised learning capabilities of the proposed design by considering a 2-layer SNN consisting of 30 neurons meant to recognize the characters 'A,' 'E,' 'I,' 'O,' and 'U,' represented with a 5 by 5 black and white pixel matrix. The SPICE simulation results indicate that the graphene SNN is able to perform unsupervised character recognition associated learning and that its recognition ability is robust to input character variations. Finally, we note that our proposal results in a small real-estate footprint (max. 30 nm^2 are required by one graphene-based device) and operates at 200 mV supply voltage, which suggest its suitability for the design of large-scale energy-efficient computing systems.","Character recognition Character recognition; graphene; spiking neural network; synaptic plasticity; unsupervised learning","en","journal article","","","","","","","","","","","Computer Engineering","","",""
"uuid:671ed708-5fb7-4a2a-94ec-3fec866b0936","http://resolver.tudelft.nl/uuid:671ed708-5fb7-4a2a-94ec-3fec866b0936","Reinforcement Learning in Railway Timetable Rescheduling","Zhu, Y. (TU Delft Transport and Planning); Wang, H. (TU Delft Railway Engineering); Goverde, R.M.P. (TU Delft Transport and Planning)","","2020","Real-time railway traffic management is important for the daily operations of railway systems. It predicts and resolves operational conflicts caused by events like excessive passenger boardings/alightings. Traditional optimization methods for this problem are restricted by the size of the problem instances. Therefore, this paper proposes a reinforcement learning-based timetable rescheduling method. Our method learns how to reschedule a timetable off-line and then can be applied online to make an optimal dispatching decision immediately by sensing the current state of the railway environment. Experiments show that the rescheduling solution obtained by the proposed reinforcement learning method is affected by the state representation of the railway environment. The proposed method was tested to a part of the Dutch railways considering scenarios with single initial train delays and multiple initial train delays. In both cases, our method found high-quality rescheduling solutions within limited training episodes.","Railway traffic management; Timetable rescheduling; Reinforcement learning","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-03-23","","","Transport and Planning","","",""
"uuid:0092343c-56bd-46d4-82d2-40f4249807af","http://resolver.tudelft.nl/uuid:0092343c-56bd-46d4-82d2-40f4249807af","PassiveVLP: Leveraging Smart Lights for Passive Positioning","Wang, Weizheng (TU Delft Embedded Systems); Wang, Q. (TU Delft Embedded Systems); Zhang, J. (TU Delft Electrical Engineering, Mathematics and Computer Science); Zuniga, Marco (TU Delft Embedded Systems)","","2020","Positioning based on visible light is gaining significant attention. But most existing studies rely on a key requirement: The object of interest needs to carry an optical receiver (camera or photodiode). We remove this requirement and investigate the possibility of achieving accurate positioning in a passive manner—that is, without requiring objects to carry any optical receiver. To achieve this goal, we propose PassiveVLP, in which we exploit the reflective surfaces of objects and the unique propagation properties of LED luminaires. We present geometric models, a testbed implementation, and empirical evaluations to showcase the opportunities and challenges posed by this new type of passive positioning. Overall, we show that our PassiveVLP can track with high accuracy (a few centimeters) a subset of an object’s trajectory, and it can also identify passively the object’s ID.","system design; visible light communication (VLC); Visible light positioning (VLP); evaluation; implementation; passive; reflection of light","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-12-06","Electrical Engineering, Mathematics and Computer Science","","Embedded Systems","","",""
"uuid:69a11ae5-e401-41d9-9ffb-ff8560e71666","http://resolver.tudelft.nl/uuid:69a11ae5-e401-41d9-9ffb-ff8560e71666","SparkRA: Enabling big data scalability for the GATK RNA-seq pipeline with apache spark","Al-Ars, Z. (TU Delft Computer Engineering); Wang, S. (TU Delft Electrical Engineering, Mathematics and Computer Science); Mushtaq, H. (TU Delft Computer Engineering)","","2020","The rapid proliferation of low-cost RNA-seq data has resulted in a growing interest in RNA analysis techniques for various applications, ranging from identifying genotype–phenotype relationships to validating discoveries of other analysis results. However, many practical applications in this field are limited by the available computational resources and associated long computing time needed to perform the analysis. GATK has a popular best practices pipeline specifically designed for variant calling RNA-seq analysis. Some tools in this pipeline are not optimized to scale the analysis to multiple processors or compute nodes efficiently, thereby limiting their ability to process large datasets. In this paper, we present SparkRA, an Apache Spark based pipeline to efficiently scale up the GATK RNA-seq variant calling pipeline on multiple cores in one node or in a large cluster. On a single node with 20 hyper-threaded cores, the original pipeline runs for more than 5 h to process a dataset of 32 GB. In contrast, SparkRA is able to reduce the overall computation time of the pipeline on the same single node by about 4×, reducing the computation time down to 1.3 h. On a cluster with 16 nodes (each with eight single-threaded cores), SparkRA is able to further reduce this computation time by 7.7× compared to a single node. Compared to other scalable state-of-the-art solutions, SparkRA is 1.2× faster while achieving the same accuracy of the results.","Apache Spark; Computation time; GATK variant calling; RNA-seq; Scalability","en","journal article","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","Computer Engineering","","",""
"uuid:6d2145c6-e94a-4c08-9cd3-5ab196a80f5c","http://resolver.tudelft.nl/uuid:6d2145c6-e94a-4c08-9cd3-5ab196a80f5c","Assessment on China's urbanization after the implementation of main functional areas planning","Xia, Han (Wuhan University); Zhang, Wanshun (Wuhan University); He, Lian (Wuhan University); Ma, Mengyue (Wuhan University; Erasmus Universiteit Rotterdam); Peng, Hong (Wuhan University); Li, Lin (Wuhan University); Ke, Q. (TU Delft Hydraulic Structures and Flood Risk); Hang, Panpan (Wuhan University); Wang, Xintang (Beijing Cstind Science and Technology Co)","","2020","China has implemented main functional areas planning (MFAP) since 2010, which is essential for improving the efficiency of land space utilization and achieving sustainable urban development. Quantitative assessments of the urban development levels (UDLs) at the county level across China after the implementation of MFAP have not been well-documented. In this study, a unified indicator system was developed, and the UDLs of 2850 counties in China after MFAP implementation were evaluated. The results showed that MFAP played a positive role in urban development in China. The UDLs in China generally increased but showed obvious spatial differences. The higher UDLs were mostly found in the counties in the five urban belts, which reflects the overall urban layout of China. The UDLs were generally low in the western counties in comparison with those in the eastern part of China. The differences in the UDLs from east to west were greater than those from north to south. Moreover, the differences in the UDLs presented a spatial agglomeration effect. This study could offer insight into the refinement of MFAP in China and sustainable urban development in developing countries.
examine the implications of aggregation progressing from a three-dimensional (3D) spatial description to a model representing a system as a
single box that exchanges sediment with the adjacent environment. We highlight how all models depend on some forms of parametric closure,
which need to be chosen to suit the scale of aggregation adopted in the model. All such models are therefore aggregated and make use of some
empirical relationships to deal with sub-scale processes. One such appropriately aggregated model, the model for the aggregated scale
morphological interaction between tidal basin and adjacent coast (ASMITA), is examined in more detail and used to illustrate the insight that this
level of aggregation can bring to a problem by considering how tidal inlets and estuaries are impacted by sea level rise.","Aggregation; Morphodynamic modelling; Sea level rise; Sediment transport; Temporal and spatial scales; Tidal inlet and estuary","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:680dd908-1669-4411-9032-b3514399a0b9","http://resolver.tudelft.nl/uuid:680dd908-1669-4411-9032-b3514399a0b9","Understanding the Working Time of Developers in IT Companies in China and the United States","Zhang, Jiayun (Fudan University); Chen, Yang (Fudan University); Gong, Qingyuan (Fudan University); Ding, Aaron Yi (TU Delft Information and Communication Technology); Xiao, Yu (Aalto University); Wang, Xin (Fudan University); Hui, Pan (The Hong Kong University of Science and Technology)","","2020","We identified three temporal patterns shown in commit activities among Chinese and American companies and found that Chinese businesses are more likely to follow long work hours than American ones. We also conducted a survey on the trends of, reasons for, and results of overtime work. Our study could provide references for developers to choose workplaces and for companies to make regulations.","China; Companies; GitHub; IT company; Moon; overtime; Rhythm; Social network services; Software; Software engineering; Time-frequency analysis; United States; working time of developers","en","journal article","","","","","","","","","","","Information and Communication Technology","","",""
"uuid:3341616f-1d54-4a2d-87d8-c01800e20d0b","http://resolver.tudelft.nl/uuid:3341616f-1d54-4a2d-87d8-c01800e20d0b","Importance of Methane Chemical Potential for Its Conversion to Methanol on Cu-Exchanged Mordenite","Zheng, Jian (Pacific Northwest National Laboratory); Lee, Insu (Technische Universität München); Khramenkova, E. (TU Delft ChemE/Inorganic Systems Engineering); Wang, Meng (Pacific Northwest National Laboratory); Peng, B. (Pacific Northwest National Laboratory); Gutiérrez, Oliver Y. (Pacific Northwest National Laboratory); Fulton, John L. (Pacific Northwest National Laboratory); Camaioni, Donald M. (Pacific Northwest National Laboratory); Pidko, E.A. (TU Delft ChemE/Algemeen; TU Delft ChemE/Inorganic Systems Engineering)","","2020","Copper-oxo clusters exchanged in zeolite mordenite are active in the stoichiometric conversion of methane to methanol at low temperatures. Here, we show an unprecedented methanol yield per Cu of 0.6, with a 90–95 % selectivity, on a MOR solely containing [Cu3(μ-O)3]2+ active sites. DFT calculations, spectroscopic characterization and kinetic analysis show that increasing the chemical potential of methane enables the utilization of two μ-oxo bridge oxygen out of the three available in the tricopper-oxo cluster structure. Methanol and methoxy groups are stabilized in parallel, leading to methanol desorption in the presence of water.","chemical potential; copper-trimer; methane oxidation; methanol production; zeolite","en","journal article","","","","","","","","","","","ChemE/Inorganic Systems Engineering","","",""
"uuid:5eb2a864-77ad-4f49-8ae0-4748fdfa66eb","http://resolver.tudelft.nl/uuid:5eb2a864-77ad-4f49-8ae0-4748fdfa66eb","Two-dimensional vehicular movement modelling at intersections based on optimal control","Zhao, J. (TU Delft Transport and Planning; University of Shanghai for Science and Technology); Knoop, V.L. (TU Delft Transport and Planning); Wang, Z. (TU Delft Architecture and the Built Environment)","","2020","Modeling traffic flow at intersections is essential for the design, control, and management of intersections. A challenging feature of microscopic modeling vehicular movement at intersections is that drivers can choose among an infinite number of alternative traveling paths and speeds. This makes it fundamentally different from structured straight road sections with lanes. This study proposes a novel method to model the trajectories of vehicles in two-dimensional space and speed. Based on optimal control theory, it assumes drivers schedule their driving behavior, including the steering and acceleration, to minimize the predicted costs. The costs contain the running costs, which consist of the travel time and driving smoothness (longitudinally and laterally), and the terminal cost, which penalizes the deviations from the desired final state. Different than conventional methods, the vehicle motion dynamics are formulated in distance rather than in time. The model is solved by an iterative numerical solution algorithm based on the Minimum Principle of Pontryagin. The descriptive power, plausibility, and accuracy of the proposed model are investigated by comparing the calculated results under several cases, which can be solved from symmetry or analytically. The proposed model is further calibrated and validated using empirical trajectory data, and the quality of the predicted trajectory is confirmed. Qualitatively, the optimal trajectory changes in the range of the shortest path and smoothest path under different weights of the running cost. The proposed model can be used as a starting point and extended with more considerations of intersection operation in the real world for future applications.","Intersections; Optimal control; Traffic flow model; Vehicular trajectory","en","journal article","","","","","","","","","Architecture and the Built Environment","","Transport and Planning","","",""
"uuid:9c9a1c3d-7981-47c2-ba46-ba99a6d024fc","http://resolver.tudelft.nl/uuid:9c9a1c3d-7981-47c2-ba46-ba99a6d024fc","Ten questions concerning well-being in the built environment","Altomonte, Sergio (Université Catholique de Louvain); Allen, Joseph (Harvard T.H. Chan School of Public Health); Bluyssen, P.M. (TU Delft Indoor Environment); Brager, Gail (University of California); Heschong, Lisa (Independent researcher); Loder, Angela (International WELL Building Institute); Schiavon, Stefano (University of California); Veitch, Jennifer (National Research Council Canada); Wang, Lily (University of Nebraska–Lincoln); Wargocki, Pawel (Technical University of Denmark)","","2020","Well-being in the built environment is a topic that features frequently in building standards and certification schemes, in scholarly articles and in the general press. However, despite this surge in attention, there are still many questions on how to effectively design, measure, and nurture well-being in the built environment. Bringing together experts from academia and the building industry, this paper aims to demonstrate that the promotion of well-being requires a departure from conventional agendas. The ten questions and answers have been arranged to offer a range of perspectives on the principles and strategies that can better sustain the consideration of well-being in the design and operation of the built environment. Placing a specific focus on some of the key physical factors (e.g., light, temperature, sound, and air quality) of indoor environmental quality (IEQ) that strongly influence occupant perception of built spaces, attention is also given to the value of multi-sensory variability, to how to monitor and communicate well-being outcomes in support of organizational and operational strategies, and to future research needs and their translation into building practice and standards. Seen as a whole, a new framework emerges, accentuating the integration of diverse new competencies required to support the design and operation of built environments that respond to the multifaceted physical, physiological, and psychological needs of their occupants.","Building standards; Comfort; Design; Health; Indoor environmental quality; Well-being","en","journal article","","","","","","","","","","","Indoor Environment","","",""
"uuid:6a31d55e-d3ba-43ab-b55c-c793ef67e82b","http://resolver.tudelft.nl/uuid:6a31d55e-d3ba-43ab-b55c-c793ef67e82b","Experimental Validation of a Gamma Detector With a Novel Light-Guide-PMT Geometry to Reduce Dead Edge Effects","Wang, B. (TU Delft RST/Biomedical Imaging); Kreuger, R. (TU Delft RST/Technici Pool); Huizenga, J. (TU Delft RST/Biomedical Imaging); Beekman, F.J. (TU Delft RST/Biomedical Imaging); Goorden, M.C. (TU Delft RST/Biomedical Imaging)","","2020","Photomultiplier tube (PMT)-based scintillation cameras are predominant in molecular imaging but have the drawback that position estimation is severely degraded near the edges (dead edge effect). This leads to sensitivity losses and can cause severe problems in applications like molecular breast imaging and in certain SPECT devices. Using smaller light sensors or semiconductor detectors can solve this issue but leads to increased costs. Here we present a gamma detector based on standard PMTs with a novel light-guide-PMT geometry that strongly reduces dead edges. In our design, a monolithic NaI(Tl) scintillator is read out by square PMTs placed in a staggered arrangement. At the edge of the scintillator we inserted additional light-guides to emulate half-size PMTs. Detector performance was assessed for 99m Tc imaging; an average spatial resolution of 3.6 mm was measured over the whole detector, degrading to 4.0 mm within 30 mm to the critical edge. The dead edge of the scintillator is <; 3 mm. Since a 12-mm seal was used, the overall dead edge is <; 15 mm, which is a significant improvement over conventional Anger cameras (~40-mm dead edge). Therefore, the presented geometry can be useful in creating economical gamma detectors with reduced dead edges.","Anger camera; dead edge; gamma detector; light-guide; molecular breast imaging; scintillator","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-11-13","","","RST/Biomedical Imaging","","",""
"uuid:ef9925ba-214e-4d38-bf44-79d8fc718f3c","http://resolver.tudelft.nl/uuid:ef9925ba-214e-4d38-bf44-79d8fc718f3c","Effects of Coordinated Formation of Vehicle Platooning in a Fleet of Shared Automated Vehicles: An Agent-based model","Wang, S. (TU Delft Mathematical Physics); Correia, Gonçalo (TU Delft Transport and Planning); Lin, H.X. (TU Delft Mathematical Physics)","","2020","This paper aims to explore the performance of the autonomous mobility-on-demand system (AMoD) with the coordinated formation of vehicle platooning. In this study, an agent-based model (ABM) is developed to explicitly simulate the operations of platooning formation and interactions between shared automated vehicles (SAVs) and real-time travel requests. The objective is to capture the real-time behavior of SAVs as trip makers, and then assess the performance of the AMoD system with the mechanism of coordinated formation of platoons. We conclude that the impact of vehicle assignment strategies in the AMoD system with vehicle platooning formation predominately affects the average waiting time and system capacity to transport travelers as a whole; however, vehicle platooning, to some extent, could lengthen the travel time of platoon vehicles. The hold-on time (imposed delay) of leading vehicles in order to form a platoon could affect the average time delay of vehicles part of those platoons. The developed ABM provides the first insight into the impact of the pervasive formation of vehicle platooning on the performance of the AMoD system.","agent-based model; demand-responsive service; shared automated vehicles; vehicle platooning","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:48433c48-8c0b-46a1-bd0f-d9472af14010","http://resolver.tudelft.nl/uuid:48433c48-8c0b-46a1-bd0f-d9472af14010","Evaluating alluvial stratigraphic response to cyclic and non-cyclic upstream forcing through process-based alluvial architecture modelling","Wang, Y. (TU Delft Applied Geology); Storms, J.E.A. (TU Delft Applied Geology); Martinius, A.W. (TU Delft Applied Geology; Statoil ASA); Karssenberg, Derek (Universiteit Utrecht); Abels, H.A. (TU Delft Applied Geology)","","2020","Formation of alluvial stratigraphy is controlled by autogenic processes that mix their imprints with allogenic forcing. In some alluvial successions, sedimentary cycles have been linked to astronomically-driven, cyclic climate changes. However, it remains challenging to define how such cyclic allogenic forcing leads to sedimentary cycles when it continuously occurs in concert with autogenic forcing. Accordingly, we evaluate the impact of cyclic and non-cyclic upstream forcing on alluvial stratigraphy through a process-based alluvial architecture model, the Karssenberg and Bridge (2008) model (KB08). The KB08 model depicts diffusion-based sediment transport, erosion and deposition within a network of channel belts and associated floodplains, with river avulsion dependent on lateral floodplain gradient, flood magnitude and frequency, and stochastic components. We find cyclic alluvial stratigraphic patterns to occur when there is cyclicity in the ratio of sediment supply over water discharge (Qs/Qw ratio), in the precondition that the allogenic forcing has sufficiently large amplitudes and long, but not very long, wavelengths, depending on inherent properties of the modelled basin (e.g. basin subsidence, size, and slope). Each alluvial stratigraphic cycle consists of two phases: an aggradation phase characterized by rapid sedimentation due to frequent channel shifting and a non-deposition phase characterized by channel belt stability and, depending on Qs/Qw amplitudes, incision. Larger Qs/Qw ratio amplitudes contribute to weaker downstream signal shredding by stochastic components in the model. Floodplain topographic differences are found to be compensated by autogenic dynamics at certain compensational timescales in fully autogenic runs, while the presence of allogenic forcing clearly impacts the compensational stacking patterns.","alluvial stratigraphy; compensational timescale; cyclicity; process-based alluvial architecture modelling; signal preservation and shredding","en","journal article","","","","","","","","","","","Applied Geology","","",""
"uuid:b78291cf-5935-4325-a7a4-2377466eb295","http://resolver.tudelft.nl/uuid:b78291cf-5935-4325-a7a4-2377466eb295","Traffic Flow Impacts of Converting an HOV Lane Into a Dedicated CACC Lane on a Freeway Corridor","Xiao, L. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning)","","2020","Cooperative Adaptive Cruise Control (CACC) systems can increase roadway capacity, but the benefits are marginal at low market penetration rates (MPRs). Thus, a CACC dedicated lane is considered to group CACC vehicles for efficient traffic stream. Concepts of converting existing High Occupancy Vehicle (HOV) lanes into CACC lanes emerge, which leverages the infrastructural facilities and experience with HOV lanes. However, it is unclear to which extent changing HOV lanes to CACC lanes can influence freeway operations. This study examines the traffic flow impacts of converting HOV lanes into CACC lanes regarding CACC MPRs on a complex freeway corridor with multiple interacting bottlenecks in California. A simulation model capable of reproducing flow characteristics with HOV lane and CACC systems is employed for the assessment. Special attention is paid to macroscopic congestion patterns, CACC lane utilization, travel time reliability and CACC operation characteristics. The results show that converting to CACC lanes at low MPRs ( % 1 )30 can exacerbate congestion in general purpose lanes, whereas at mediate CACC MPRs (40%–50%) the congestion is drastically alleviated due to a large share of traffic carried by CACC lanes.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-06-17","","","Transport and Planning","","",""
"uuid:35492ec8-16f2-4f8b-8919-8b395efc44c1","http://resolver.tudelft.nl/uuid:35492ec8-16f2-4f8b-8919-8b395efc44c1","An integrated optic and acoustic (IOA) approach for measuring suspended sediment concentration in highly turbid environments","Lin, J. (TU Delft Coastal Engineering; East China Normal University); He, Qing (East China Normal Univeristy); Guo, Leicheng (East China Normal University); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Wang, Zhengbing (TU Delft Coastal Engineering; East China Normal University; Deltares)","","2020","Accurate measurement of suspended sediment concentration (SSC) in highly turbid environments has been a problem due to optical or acoustic signal saturation and attenuation. The saturation returns a limited measurement range, and the attenuation raises an ambiguity problem that a low optical or acoustic output could mean a low or a high SSC. In this study, an integrated optic and acoustic (IOA) approach is proposed to (i) overcome the ambiguity problem; (ii) increase the measurement range to high SSC values; and (iii) obtain high-resolution SSC profiles. The IOA approach is a combination of Argus Suspension Meter (ASM), Optical Backscatter Sensor (OBS) and Acoustic Doppler Velocimeter (ADV). In this approach, the ASM-derived SSC is preferred because of its lowest relative error, followed by OBS and ADV. The ASM can produce high-resolution (1 cm interval) SSC profiles when it is not saturated (usually SSC < 9 g/L). When ASM is saturated, the SSC is recovered by OBS. Since the ambiguity problem is solved, the measurement range of OBS and ADV can be extended up to 300 g/L. The best way to use an ADV, however, is to have a rough estimation first and assist in the OBS conversion, because its estimates contain large uncertainty. To further mitigate the impact of sediment particle size on SSC retrieval, we suggest the usage of in-situ sediment samples for sensor calibration. The IOA approach was verified in the Yangtze Estuary which is a highly turbid system. Comparison of the IOA approach outputs against water sampling results demonstrates the reliability of the IOA approach with a relative error of 17–34%. The observed high SSCs were up to 63 g/L. The field data show that high SSCs were confined in the benthic layer (within 2 m above the bed) in the wet season under a high river discharge, whereas the suspension was better mixed throughout the water column in the dry season.","Acoustic Doppler Velocimeter; Argus Suspension Meter; Concentrated benthic suspension; Optical Backscatter Sensor; Suspended sediment concentration","en","journal article","","","","","","Accepted Author Manuscript","","2021-12-16","","","Coastal Engineering","","",""
"uuid:d1990450-d851-4dfb-8faf-25d7fd4e2506","http://resolver.tudelft.nl/uuid:d1990450-d851-4dfb-8faf-25d7fd4e2506","The role of thermodynamics and kinetics in rubber–bitumen systems: a theoretical overview","Wang, H. (TU Delft Pavement Engineering); Apostolidis, P. (TU Delft Pavement Engineering); Zhu, Jiqing (Swedish National Road and Transport Research Institute); Liu, X. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Khalifa University of Science and Technology); Erkens, S. (TU Delft Pavement Engineering)","","2020","Waste tire rubber has been incorporated into asphalt modification for decades due to its various benefits. There are two main mechanisms during bitumen–rubber interaction: rubber swelling and chemical degradation. This study surveys these two processes from the viewpoint of polymer science. The kinetics of rubber dissolution and thermodynamics of rubber swelling are discussed to provide a fundamental understanding of the interaction process and to demonstrate how optimisation of material selection and processing procedures can lead to the desired binder properties. Factors including the interaction conditions and raw material characteristics are analysed based on the previous theories and compared with experimental results.","chemical degradation; Crumb rubber modified bitumen; diffusion; solubility; swelling; thermodynamics","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:f1df261f-fc1d-49cc-bd2d-31b82d86fb09","http://resolver.tudelft.nl/uuid:f1df261f-fc1d-49cc-bd2d-31b82d86fb09","High-precision frequency sweeping interferometry for absolute distance measurement using a tunable laser with sweeping range of 88 GHz","Shi, G. (TU Delft ImPhys/Optics; Hangzhou Dianzi University); Hei, K. (TU Delft ImPhys/Optics); Wang, Wen (Hangzhou Dianzi University); Bhattacharya, N. (TU Delft ImPhys/Medical Imaging)","","2020","Distance measurement using frequency sweeping interferometry is an absolute distance measurement technique that allows for high accuracy over long distances. Notwithstanding, the measurement accuracy is affected by laser sweeping nonlinearity and limited sweeping range. In this work, an optimized post-processing linearization method is demonstrated to realize high-accuracy arbitrary distance measurement using a laser with small modulation range. The interference signal is sparsely resampled to eliminate the influence of the sweeping nonlinearity, and the absolute distance is obtained by analyzing the phase of the resampled signal. In the measurement system, a high-finesse Fabry-Pérot cavity placed in vacuum is used as the measurement reference, so the effect of dispersion mismatch is negligible. Moreover, the distance measurement result is determined by the linear fit of the phase of each resampled point. Therefore, the influence of target vibration and other external random noise can be partially eliminated, and the reliability of the result is high. In the experiment, the sweeping range of the laser source is only 88 GHz. Comparing with a fringe-counting interferometer, the standard deviation of the residual errors is 34 µm within a distance of 6.7 m.","absolute distance measurement; frequency sweeping interferometry; laser distance measurement","en","journal article","","","","","","Accepted Author Manuscript","","2021-01-06","","","ImPhys/Optics","","",""
"uuid:f4926d0e-a03b-49c7-ad5c-eadb0b9bf1f3","http://resolver.tudelft.nl/uuid:f4926d0e-a03b-49c7-ad5c-eadb0b9bf1f3","Dynamic Response of the Fluid Mud to a Tropical Storm","Ge, Jianzhong (Shanghai Estuarine and Coastal Science Research Center; Institute of Eco-Chongming (IEC)); Chen, Changsheng (University of Massachusetts Lowell); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); Ke, Keteng (Shanghai Investigation Design and Research Institute Co.; Shanghai Estuarine and Coastal Science Research Center); Yi, Jinxu (Shanghai Investigation Design and Research Institute Co.); Ding, Ping Xing (Shanghai Investigation Design and Research Institute Co.)","","2020","Fluid mud (FM) is a unique sedimentary feature in high-turbidity estuaries, where it can make a rapid contribution to morphodynamics. Insufficient field measurements and fixed-point monitoring lead to deficient understandings of the formation, transport, and breakdown of the FM under extreme weather conditions. A field survey was conducted in the Changjiang Estuary during the period of turbidity maximum, just after Typhoon Haikui. The measurements captured the formation of the FM beneath the suspended layers, particularly around the lower reach of the North Passage. The thickness of the observed FM gradually decreased landward along the channel, with the maximum value reaching ~0.9 m. The major features of the observed storm-induced FM were simulated using the Finite-Volume Community Ocean Model. The results indicated that the initial appearance of the FM was the result of a typhoon-intensified, salinity-induced stratification in the outlet region. The subsequent landward propagation of the FM was driven by the combined effects of the FM-induced mud surface pressure gradient force and saltwater intrusion near the bottom. Weak mixing during the subsequent neap tidal period sustained the FM as it rapidly extended into the middle region of the North Passage. This produced a large velocity shear at the interface of the FM and upper suspension layer, increasing the entrainment from the FM to the upper suspension layer. As a result of the increased tidal mixing, the FM weakened and then finally broke down in the subsequent spring tidal period.","fluid mud; FVCOM; saltwater intrusion; sediment dynamics; simulation; storm impact","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-09-10","","","Coastal Engineering","","",""
"uuid:b1563fb1-ff78-44e3-821d-ddbff633fb9b","http://resolver.tudelft.nl/uuid:b1563fb1-ff78-44e3-821d-ddbff633fb9b","Shadow-free motorized capsule enables accurate beam positioning and sectorized OCT imaging of the esophagus","López-Marín, Antonio (Erasmus MC); Springeling, Geert (Erasmus MC); Beurskens, Robert (Erasmus MC); Van Beusekom, Heleen (Erasmus MC); van der Steen, A.F.W. (TU Delft ImPhys/Medical Imaging; Erasmus MC; Chinese Academy of Sciences); Koch, Arjun D. (Erasmus MC); Bouma, Brett E. (Massachusetts General Hospital/Harvard Medical School); Huber, Robert A. (University of Lübeck); Van Soest, Gijs (Erasmus MC); Wang, Tianshi (Erasmus MC)","Tearney, Guillermo J. (editor); Wang, Thomas D. (editor); Suter, Melissa J. (editor)","2020","In this study, we demonstrate a 12x36 mm motorized capsule for OCT imaging of the esophagus. The capsule produces unobstructed images by using a distal reflector design, thus avoiding shadow caused by the motor wires. The motor synchronous control enables three working modes: circumferential imaging, angular sector imaging and accurate beam positioning. Distortion artifacts shown in the sector imaging were found to be induced by velocity changes of the motor. We specifically characterized the motor speed and found a symmetric and repeatable behavior during sector scanning. Resampling of the sector images A-lines was carried out to achieve uniform angular spacing according to the measured speed profile. Also, distortion between consecutive sector frames was corrected using image registration to achieve stable imaging.","Gradient index lenses; Image reconstruction; Light beams; Magnetic fields; Optical Coherence Tomography; Optical imaging","en","conference paper","SPIE","","","","","","","","","","ImPhys/Medical Imaging","","",""
"uuid:f86257c3-8b7a-4bc9-bfaa-0eea8200ce9f","http://resolver.tudelft.nl/uuid:f86257c3-8b7a-4bc9-bfaa-0eea8200ce9f","Thermo-elastic optical coherence microscopy","Doug Deen, Aaron (Erasmus MC); Pfeiffer, Tom (University of Lübeck); Van Beusekom, Heleen (Erasmus MC); Essers, J. (Erasmus MC); Huber, Robert (University of Lübeck); van der Steen, A.F.W. (TU Delft ImPhys/Medical Imaging; Erasmus MC; Chinese Academy of Sciences); Van Soest, Gijs (Erasmus MC); Wang, Tianshi (Erasmus MC)","Cheng, Ji-Xin (editor); Min, Wei (editor); Simpson, Garth J. (editor)","2020","The absorption of laser pulses by tissue leads not only to the generation of acoustic waves, but also to nanometer to sub-micrometer scale displacement. After the initial expansion, a quasi-steady state is achieved in a few microseconds. Previously we introduced the concept of thermo-elastic optical coherence tomography (TE-OCT) to ""visualise"" the rapid thermo-elastic expansion by measuring the Doppler phase shift rather than istening"" to the acoustic wave as in photoacoustic imaging. In this study, we built a microscopic setup for high-speed 3D TE-OCT imaging, by means of thermo-elastic optical coherence microscopy (TE-OCM). The repetition rate of pulsed laser was set to 100 Hz and the line rate of the OCT system is 1.5 MHz. The OCT beam and the laser pulse were focused upon the same location on the sample FWHM spot sizes of 300 μm for the pulsed laser and 40 μm FWHM for the OCT beam. For each laser pulse, an M-mode OCT image consisting of 90 A-lines was acquired. The Doppler phase shift was extracted by comparing the phase signal before and after the pulse arrival. Within 6 minutes, a 3D TE-OCM image (10 × 10 × 4 mm3) can be acquired and processed. Imaging experiments were carried out in swine meat using 1210 nm excitation wavelength to highlight lipid in tissue. The results show that no significant displacement was detected in swine muscle while strong displacement was observed in lipid, owing to the optical absorption features. Furthermore, fatty tissue is easily identified in the 3D TE-OCM image while the conventional OCT images provides the structural information.","","en","conference paper","SPIE","","","","","","","","","","ImPhys/Medical Imaging","","",""
"uuid:1fb01798-c514-4dc9-82c8-5cf038b2136e","http://resolver.tudelft.nl/uuid:1fb01798-c514-4dc9-82c8-5cf038b2136e","Machine learning for automatic construction of pediatric abdominal phantoms for radiation dose reconstruction","Virgolin, M. (Centrum Wiskunde & Informatica (CWI)); Wang, Ziyuan (Universiteit van Amsterdam); Alderliesten, T. (Universiteit van Amsterdam); Bosman, P.A.N. (TU Delft Algorithmics; Centrum Wiskunde & Informatica (CWI))","Chen, Po-Hao (editor); Deserno, Thomas M. (editor)","2020","The advent of Machine Learning (ML) is proving extremely beneficial in many healthcare applications. In pediatric oncology, retrospective studies that investigate the relationship between treatment and late adverse effects still rely on simple heuristics. To capture the effects of radiation treatment, treatment plans are typically simulated on virtual surrogates of patient anatomy called phantoms. Currently, phantoms are built to represent categories of patients based on reasonable yet simple criteria. This often results in phantoms that are too generic to accurately represent individual anatomies. We present a novel approach that combines imaging data and ML to build individualized phantoms automatically. We design a pipeline that, given features of patients treated in the pre-3D planning era when only 2D radiographs were available, as well as a database of 3D Computed Tomography (CT) imaging with organ segmentations, uses ML to predict how to assemble a patient-specific phantom. Using 60 abdominal CTs of pediatric patients between 2 to 6 years of age, we find that our approach delivers significantly more representative phantoms compared to using current phantom building criteria, in terms of shape and location of two considered organs (liver and spleen), and shape of the abdomen. Furthermore, as interpretability is often central to trust ML models in medical contexts, among other ML algorithms we consider the Gene-pool Optimal Mixing Evolutionary Algorithm for Genetic Programming (GP-GOMEA), that learns readable mathematical expression models. We find that the readability of its output does not compromise prediction performance as GP-GOMEA delivered the best performing models.","Dose reconstruction; Machine learning; Pediatric cancer; Phantom; Radiation treatment","en","conference paper","SPIE","","","","","","","","","","Algorithmics","","",""
"uuid:1d0a18e4-a7eb-46bf-bbf2-5f73d516d441","http://resolver.tudelft.nl/uuid:1d0a18e4-a7eb-46bf-bbf2-5f73d516d441","Production of fatty alcohols from non-edible oils by enzymatic cascade reactions","Ma, Yunjian (South China University of Technology); Zhang, Xizhen (South China University of Technology); Li, Yongru (South China University of Technology); Li, Peilin (South China University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Yonghua (South China University of Technology)","","2020","A biocatalytic cascade transforming castor oil into (R,Z)-octadec-9-en-7-ol is presented by combining a lipase catalysed hydrolysis of castor oil into ricinoleic acid followed by a photoenzymatic decarboxylation into (R,Z)-octadec-9-en-7-ol. Conversion of up to 41.7% and overall product concentrations of up to 60 mM, this new bienzymatic and photocatalytic cascade exhibits significant potential for the valorisation of non-edible castor oil. The scope and limitations of the current system are described and discussed.","","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:8785c8f0-319a-4385-901c-05a215b641a0","http://resolver.tudelft.nl/uuid:8785c8f0-319a-4385-901c-05a215b641a0","Designing sexuality and intimacy care for adolescents and young adults (AYAs) with cancer","Wang, Ruocha (Student TU Delft); Groeneveld, B.S. (TU Delft Applied Ergonomics and Design); Albers, Leonore (Leiden University Medical Center); Desmet, P.M.A. (TU Delft Design Aesthetics)","Christer, K. (editor); Craig, C. (editor); Chamberlain, P. (editor)","2020","Adolescents and Young Adults (AYAs) with Cancer are making the transition from childhood to adulthood while handling the burden of cancer. During this extraordinarily challenging time in their growth and development, sexuality and intimacy, an important aspect of AYAs’ wellbeing, are often insufficiently addressed by the healthcare providers, and AYAs are dissatisfied with the available information. The objective of this study was to develop objectives that could help design properly address sexuality and intimacy in AYA care along with a design prototype. The research investigated the big picture of sexuality and intimacy care for AYAs in the Netherlands and looked into AYAs’ unmet needs through literature study, interviews with AYA using the Q-sort method and interviews with healthcare providers. The list of design objectives was proposed based on the interviewees’ opinions and insights, along with an iterative prototype designed by the researcher that reflected the objectives. Through a cyclic interview process, the list of design objectives was revised, and the prototype was refined as a possible solution in the end. Finally, a conclusion on the research findings and the design objectives is provided","Adolescents and young adults (AYAs) with cancer; human-centred design; sexuality and intimacy; sexual health; online intervention","en","conference paper","Sheffield Hallam University","","","","","accepted author manuscript","","","","","Applied Ergonomics and Design","","",""
"uuid:beb4ea3c-f012-414f-a3d8-d2a51f26dd2a","http://resolver.tudelft.nl/uuid:beb4ea3c-f012-414f-a3d8-d2a51f26dd2a","Time dependence of susceptible-infected-susceptible epidemics on networks with nodal self-infections","Van Mieghem, P.F.A. (TU Delft Network Architectures and Services); Wang, F. (TU Delft Network Architectures and Services)","","2020","The average fraction of infected nodes, in short the prevalence, of the Markovian ɛ-SIS (susceptible-infected-susceptible) process with small self-infection rate ɛ>0 exhibits, as a function of time, a typical ""two-plateau"" behavior, which was first discovered in the complete graph KN. Although the complete graph is often dismissed as an unacceptably simplistic approximation, its analytic tractability allows to unravel deeper details, that are surprisingly also observed in other graphs as demonstrated by simulations. The time-dependent mean-field approximation for KN performs only reasonably well for relatively large self-infection rates, but completely fails to mimic the typical Markovian ɛ-SIS process with small self-infection rates. While self-infections, particularly when their rate is small, are usually ignored, the interplay of nodal self-infection and spread over links may explain why absorbing processes are hardly observed in reality, even over long time intervals.","","en","journal article","","","","","","","","","","","Network Architectures and Services","","",""
"uuid:6ca465c1-d132-4d86-9226-b9750a00e23a","http://resolver.tudelft.nl/uuid:6ca465c1-d132-4d86-9226-b9750a00e23a","Influence of wheel polygonal wear on wheel-rail dynamic contact in a heavy-haul locomotive under traction conditions","Liang, Hongqin (Southwest Jiaotong University); Liu, Pengfei (Shijiazhuang Tiedao University); Wang, Tianlong (Shijiazhuang Tiedao University); Wang, Haoyu (TU Delft Mechanics and Physics of Structures); Zhang, Kailong (Shijiazhuang Tiedao University); Cao, Yunqiang (Shijiazhuang Tiedao University); An, Dong (Southwest Jiaotong University)","","2020","For a heavy-haul locomotive within a wheel repairing period, wheel polygonal wear with different operating mileages is obtained by field testing. The test results show that the maximum radial runout of the wheel can increase to 0.87 mm and accompany with the typical damage of wheel tread shelling. Taking the wheel polygons as input excitation, the locomotive-track coupled dynamic model is established, which is verified by the comparisons of test and calculated wheelset vertical acceleration in time and frequency domains. The variable wheel-rail friction coefficient is introduced so as to consider the dry and wet rail conditions. The wheel-rail dynamic contact characteristics under the traction and dry-wet rail surface conditions are analysed simultaneously. It is found that the wheel polygon deteriorates the locomotive traction performance and induces the obvious wheel-rail slipping with large tangential stress, especially in wet rail condition. In dry condition, the wheel-rail could contact generally in the adhesion state. But the longitudinal creep forces fluctuate locally with some larger amplitudes closed to the adhesion force, which is mainly attributed to the excitation of serious wheel polygon. Comparing with the results of the newly repaired wheel, the maximum wheel-rail vertical force, longitudinal force, normal stress and tangential stress at the end of wheel repairing period can increase by 55 kN, 28 kN, 240 MPa and 470 MPa in sequence. The wheel-rail slipping and high-stress state in traction condition should be the dominant factors contributing to the wheel damage of tread shelling.","Heavy-haul locomotive; traction; wheel polygon; wheel-rail contact","en","journal article","","","","","","Accepted author manuscript","","","","","Mechanics and Physics of Structures","","",""
"uuid:4b8effa1-2e61-4ab7-babc-47f432003f92","http://resolver.tudelft.nl/uuid:4b8effa1-2e61-4ab7-babc-47f432003f92","Wideband Direction of Arrival Estimation with Sparse Linear Arrays","Wang, F. (TU Delft Signal Processing Systems; University of Electronic Science and Technology of China); Tian, Zhi (George Mason University); Fang, Jun (University of Electronic Science and Technology of China); Leus, G.J.T. (TU Delft Signal Processing Systems)","","2020","This paper concerns wideband direction of arrival (DoA) estimation with sparse linear arrays (SLAs). We rely on the assumption that the power spectrum of the wideband sources is the same up to a scaling factor, which could in theory allow us to resolve not only more sources than the number of antennas but also more sources than the number of degrees of freedom (DoF) of the difference co-array of the SLA. We resort to the Jacobi-Anger approximation to transform the coarray response matrices of all frequency bins into a single virtual uniform linear array (ULA) response matrix. Based on the obtained model, two super-resolution DoA estimation approaches based on atomic norm minimization (ANM) are proposed, one with and one without prior knowledge of the power spectrum. Simulation results show that our proposed methods outperform the state of the art and are indeed capable of resolving more sources than the number of DoF of the difference co-array.","Jacobi-Anger approximation; Wideband direction of arrival (DoA) estimation; atomic norm minimization (ANM); sparse linear array (SLA)","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-11-14","","","Signal Processing Systems","","",""
"uuid:90ec1e0d-ebd1-4255-9443-c9188c88a64c","http://resolver.tudelft.nl/uuid:90ec1e0d-ebd1-4255-9443-c9188c88a64c","Learning connectivity and higher-order interactions in radial distribution grids","Yang, Qiuling (Beijing Institute of Technology); Coutino, Mario (TU Delft Signal Processing Systems); Wang, Gang (University of Minnesota); Giannakis, Georgios B. (University of Minnesota); Leus, G.J.T. (TU Delft Signal Processing Systems)","","2020","To perform any meaningful optimization task, distribution grid operators need to know the topology of their grids. Although power grid topology identification and verification has been recently studied, discovering instantaneous interplay among subsets of buses, also known as higher-order interactions in recent literature, has not yet been addressed. The system operator can benefit from having this knowledge when re-configuring the grid in real time, to minimize power losses, balance loads, alleviate faults, or for scheduled maintenance. Establishing a connection between the celebrated exact distribution flow equations and the so-called self-driven graph Volterra model, this paper puts forth a nonlinear topology identification algorithm, that is able to reveal both the edge connections as well as their higher-order interactions. Preliminary numerical tests using real data on a 47-bus distribution grid showcase the merits of the proposed scheme relative to existing alternatives.","Distribution microgrid; Graph; Higher-order interaction; Topology identification; Volterra model","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-11-14","","","Signal Processing Systems","","",""
"uuid:76ab6fca-e355-4c15-9913-eff404e0ae5b","http://resolver.tudelft.nl/uuid:76ab6fca-e355-4c15-9913-eff404e0ae5b","Efficient Super-Resolution Two-Dimensional Harmonic Retrieval Via Enhanced Low-Rank Structured Covariance Reconstruction","Wang, Yue (George Mason University); Zhang, Yu (Nanjing University of Aeronautics and Astronautics; George Mason University); Tian, Zhi (George Mason University); Leus, G.J.T. (TU Delft Signal Processing Systems); Zhang, Gong (Nanjing University of Aeronautics and Astronautics)","","2020","This paper develops an enhanced low-rank structured covariance reconstruction (LRSCR) method based on the decoupled atomic norm minimization (D-ANM), for super-resolution two-dimensional (2D) harmonic retrieval with multiple measurement vectors. This LRSCR-D-ANM approach exploits a potential structure hidden in the covariance by transferring the basic LRSCR to an efficient D-ANM formulation, which permits a sparse representation over a matrix-form atom set with decoupled 1D frequency components. The new LRSCR-D-ANM method builds upon the existence of a generalized Vandermonde decomposition of its solution, which otherwise cannot be guaranteed by the basic LRSCR unless a very conservative condition holds. Further, a low-complexity solution of the LRSCR-D-ANM is provided for fast implementation with negligible performance loss. Simulation results verify the advantages of the proposed LRSCR-D-ANM over the basic LRSCR, in terms of the wider applicability and the lower complexity.","2D harmonic retrieval; D-ANM; LRSCR; MMV; Super-resolution","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-11-14","","","Signal Processing Systems","","",""
"uuid:24de5221-cd42-4be4-8fa4-ef55523a27fa","http://resolver.tudelft.nl/uuid:24de5221-cd42-4be4-8fa4-ef55523a27fa","A hierarchical approach for splitting truck platoons near network discontinuities","Duret, Aurelien (Institut Francais des Sciences et Technologies des Transports (IFSTTAR)); Wang, M. (TU Delft Transport and Planning); Ladino, Andres (Institut Francais des Sciences et Technologies des Transports (IFSTTAR))","","2020","Truck platooning has attracted substantial attention due to its pronounced benefits in saving energy and promising business model in freight transportation. However, one prominent challenge for the successful implementation of truck platooning is the safe and efficient interaction with surrounding traffic, especially at network discontinuities where mandatory lane changes may lead to the decoupling of truck platoons. This contribution puts forward an efficient method for splitting a platoon of vehicles near network merges. A model-based bi-level control strategy is proposed. A supervisory tactical strategy based on a first-order car-following model with bounded acceleration is designed to maximize the flow at merge discontinuities. The decisions taken at this level include optimal vehicle order after the merge, new equilibrium gaps of automated trucks at the merging point, and anticipation horizon that the platoon members start to track the new equilibrium gaps. The lower-level operational layer uses a third-order longitudinal dynamics model to compute the optimal truck accelerations so that new equilibrium gaps are created when merging vehicles start to change lane and the transient maneuvers are efficient, safe and comfortable. The tactical decisions are derived from an analytic car-following model and the operational accelerations are controlled via model predictive control with guaranteed stability. Simulation experiments are provided in order to test the feasibility and demonstrate the performance and robustness of the proposed strategy.","Cooperative merging; Cooperative systems; Hierarchical control; Model predictive control; Traffic flow model; Truck platooning","en","journal article","","","","","","","","2022-02-28","","","Transport and Planning","","",""
"uuid:3eb663a2-be22-4142-bac8-94aff261c1be","http://resolver.tudelft.nl/uuid:3eb663a2-be22-4142-bac8-94aff261c1be","Microwave heating simulation of asphalt pavements","Wang, H. (TU Delft Pavement Engineering); Apostolidis, P. (TU Delft Pavement Engineering); Zhang, H. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Erkens, S. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Khalifa University of Science and Technology)","Kumar, A. (editor); Papagiannakis, A.T. (editor); Bhasin, A. (editor); Little, D. (editor)","2020","Microwave heating is a promising heating technology for the maintenance, recycling and deicing of pavement structures. Many experimental studies have been conducted to investigate the microwave heating properties of asphalt mixtures in the laboratory. However, very few studies investigated the application of microwave heating on asphalt pavements. This study aims to simulate microwave heating of paving materials using the finite element method. Results show that the developed three-dimensional model, which couples the physics of electromagnetic waves and heat transfer, shows a great potential for optimizing the design of microwave heating prototypes for pavement applications.","","en","conference paper","Taylor and Francis","","","","","Accepted Author Manuscript","","2021-08-07","","","Pavement Engineering","","",""
"uuid:4866e2e2-5417-4fc4-b63c-ed6c37fcba03","http://resolver.tudelft.nl/uuid:4866e2e2-5417-4fc4-b63c-ed6c37fcba03","Oxidation simulation of thin bitumen film","Apostolidis, P. (TU Delft Pavement Engineering); Wang, H. (TU Delft Pavement Engineering); Zhang, H. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Erkens, S. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Khalifa University of Science and Technology)","Kumar, A. (editor); Papagiannakis, A.T. (editor); Bhasin, A. (editor); Little, D. (editor)","2020","Oxidative aging is a complex phenomenon in bitumen and its fundamental understanding is needed to optimize paving materials with long-lasting characteristics. This research reports on a diffuse-reaction model for predicting the oxidation of bituminous binders over time and under different conditions. As known, the oxidation of bitumen is affected by the material chemistry, film thickness and temperature. Thus, these factors were considered in this research to simulate the oxidation of a thin bitumen film. Carbon compounds were assumed as the oxidation index of a model bitumen and analyses were performed enabling prediction of chemical compositional changes. In the future, the current model can be used to simulate the actual oxidative aging in (un)modified binders, such as epoxy modified asphalt, presented in a companion paper (Apostolidis et al., Kinetics of Epoxy-Asphalt Oxidation. AM3P).","","en","conference paper","Taylor and Francis","","","","","Accepted Author Manuscript","","2021-08-07","","","Pavement Engineering","","",""
"uuid:e81050bd-7813-4df6-afe2-0a3fe83ef871","http://resolver.tudelft.nl/uuid:e81050bd-7813-4df6-afe2-0a3fe83ef871","Dissolution simulation of polymers in bitumen","Wang, H. (TU Delft Pavement Engineering); Apostolidis, P. (TU Delft Pavement Engineering); Zhang, H. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Erkens, S. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Khalifa University of Science and Technology)","Kumar, A. (editor); Papagiannakis, A.T. (editor); Bhasin, A. (editor); Little, D. (editor)","2020","Fundamental models should be developed and utilized in order to facilitate the chemo-mechanical design of modified binder systems for paving applications but not only. Especially, the fact that the incorporation of new chemical substances used as bio-based modifiers or alternative binders is attracting great interest to replace traditional technologies, the development of tools able to provide insight into the various physio-chemical phenomena is crucial. Among other polymer-bitumen interaction phenomena, the dissolution mechanism of polymers in bitumen is a significant aspect that should be considering in order to enhance binder properties through polymer modification. The current research gives emphasis on modelling the mechanism of dissolution for rubbery polymers in bitumen.","","en","conference paper","Taylor and Francis","","","","","Accepted Author Manuscript","","2021-08-07","","","Pavement Engineering","","",""
"uuid:0155bc24-cac4-4846-93d0-a509bd2b8a47","http://resolver.tudelft.nl/uuid:0155bc24-cac4-4846-93d0-a509bd2b8a47","Design and Real-Time Implementation of a Vision-Based Adaptive Model-Free Morphing Wing Motion Control Method [PPT]","Mkhoyan, T. (TU Delft Aerospace Structures & Computational Mechanics); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics); de Visser, C.C. (TU Delft Control & Simulation); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics)","","2020","The advancements made in aircraft control methodology and the tendency towards increasingly lighter aircraft structures open the opportunity to higher structural performance and aerodynamic efficiency. However, with the reduction of structure weight, the structure stiffness reduces typically, which makes the structure more susceptible to external dynamic loads. How the flexibility affects the dynamics of the system, in particular in closed-loop control, cannot always be determined in the early stage of the design process. This introduces uncertainties to the dynamic model and consequently leads to inaccurate performance evaluation. Our proposed approach to fully utilize the potential of the lighter aircraft structure is to actively morph it using distributed actuators commanded by a real-time multi-objective controller. In the literature, model-based feedback control methods are widely used for flexible structure motion suppression. However, the performance of model-based controllers is impaired by model uncertainties and external disturbances. Another challenge in flexible structure control is the real-time state estimation. Although accelerometers and strain gauges can be used to capture the structural vibrations, these sensors have to be installed within the structure, which increases the difficulties in maintenance. A potentially universal, model-free, and non-invasive approach is visual tracking. In combination with robust model-free control laws, this has the potential to create smart adaptive structures that are capable of vibration suppression. In this study, an adaptive model-free state estimation methodology based on visual feedback is developed and demonstrated in unison with a non-linear model-free robust control method in a closed-loop system. The experimental setup consists of high-speed GIGE cameras observing oscillations from a clamped beam subject to disturbances at 140 Hz. The task of the controller is to reject the disturbances through a shaker input under the presence of parametric model uncertainties and external disturbances. The visual tracking utilizes adaptive estimation utilizing high-speed KCF (Kernelized Correlation Filter) tracking and an AEKF (Augmented Extended Kalman Filter) with augmented time-varying mass, stiffness, and damping states. The inclusion of the augmented Kalman filter adds robustness to occlusion and model uncertainties. The nonlinear model-free control method is developed in the incremental control framework, hybridized with sliding mode control for robustness enhancement. The control effectiveness matrix used by the controller is adapted online. Furthermore, the state and state derivative feedback signals are provided by the visual system in real-time. This research is a part of the Smart-X wing project, which represents an autonomous smart morphing wing that is capable of in-flight performance optimisation of multiple objectives. It is shown in this research that the combination of adaptive visual tracking and robust control shows how a flexible uncertain structure can be transformed into a controlled adaptive smart structure. This combination of visual tracking and control shows great potential for robust and model-free stabilization and vibration suppression. Further uses of the methodology are discussed for use in tracking problems for flexible and aeroelastic structures.","","en","other","","","","","","","","","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:5b99f171-2fb8-4d7a-88ed-7d19646bd714","http://resolver.tudelft.nl/uuid:5b99f171-2fb8-4d7a-88ed-7d19646bd714","Stability Evaluation of Concrete Structure Considering the Local Damage Using Nondestructive Detection and Numerical Analysis","Tan, Xuyan (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Chen, Weizhong (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Wang, L. (TU Delft Numerical Analysis; Chinese Academy of Sciences); Yang, Jianping (Chinese Academy of Sciences; University of Chinese Academy of Sciences)","","2020","Shield tunneling is one of the most important technologies for building of underground engineering. Many grouting holes were prefabricated for the requirement of backfill grouting, which is easy to induce local damages and potential disasters, such as leakage and cracking. Accordingly, an integrated workflow for damage detection and stability evaluation was performed based on nondestructive testing (NDT) and numerical simulation. As a case study, this method was applied to an underwater shield tunnel. Firstly, Ground Penetrating Radar (GPR) was used to detect the conditions in grouting holes. Then, the infrared camera was used to determine the damaged positions induced by grouting holes. According to NDT results, the numerical models were developed to analyze the mechanical behaviors of structure. It indicated the geophysical inversion results are consistent with field conditions. The influence area increases with a significant value of water pressure, and stress magnitude would increase to 45KPa if the increment of water pressure reaches to 10KPa. As a promising application, structure stability was evaluated in the light of analytical results.","Mechanical behaviors; Nondestructive testing; Numerical analysis; Stability","en","journal article","","","","","","","","","","","Numerical Analysis","","",""
"uuid:b4015f33-221f-4ca9-af69-161cd054dd31","http://resolver.tudelft.nl/uuid:b4015f33-221f-4ca9-af69-161cd054dd31","Real-Time Coupling of Geographically Distributed Research Infrastructures: Taxonomy, Overview and Real-World Smart Grid Applications","Syed, M.H. (University of Strathclyde); Guillo-Sansano, E. (University of Strathclyde); Wang, Y. (Rolls-Royce); Vogel, S. (Rheinisch-Westfälische Technische Hochschule); Palensky, P. (TU Delft Intelligent Electrical Power Grids); Burt, G. M. (University of Strathclyde); Xu, Y. (Nanyang Technological University); Monti, A. (Rheinisch-Westfälische Technische Hochschule); Hovsapian, R. (National Renewable Energy Laboratory)","","2020","Novel concepts enabling a resilient future power system and their subsequent experimental evaluation are experiencing a steadily growing challenge: large scale complexity and questionable scalability. The requirements on a research infrastructure (RI) to cope with the trends of such a dynamic system therefore grow in size, diversity and costs, making the feasibility of rigorous advancements questionable by a single RI. Analysis of large scale system complexity has been made possible by the real-time coupling of geographically separated RIs undertaking geographically distributed simulations (GDS), the concept of which brings the equipment, models and expertise of independent RIs, in combination, to optimally address the challenge. This article presents the outputs of IEEE PES Task Force on Interfacing Techniques for Simulation Tools towards standardization of GDS as a concept. First, the taxonomy for setups utilized for GDS is established followed by a comprehensive overview of the advancements in real-time couplings reported in literature. The overview encompasses fundamental technological design considerations for GDS. The article further presents four application oriented case studies (real-world implementations) where GDS setups have been utilized, demonstrating their practicality and potential in enabling the analysis of future complex power systems.","Geographically distributed simulations; distributed laboratories; geographically distributed research infrastructures; multi-site simulations; power and energy systems validation; real-time coupling of geographically distributed research infrastructures; real-time simulations; remote coupling","en","journal article","","","","","","""Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.""","","2021-12-22","","","Intelligent Electrical Power Grids","","",""
"uuid:956cb21d-d1dc-4446-a7c3-9037a8cea914","http://resolver.tudelft.nl/uuid:956cb21d-d1dc-4446-a7c3-9037a8cea914","Revealing High Na-Content P2-Type Layered Oxides as Advanced Sodium-Ion Cathodes","Zhao, Chenglong (University of Chinese Academy of Sciences); Yao, Zhenpeng (Harvard University); Wang, Qidi (Tsinghua University); Li, Haifeng (University of Illinois at Chicago); Wang, Jianlin (Chinese Academy of Sciences); Liu, M. (TU Delft RST/Storage of Electrochemical Energy); Ganapathy, S. (TU Delft RID/TS/Instrumenten groep); Lu, Yaxiang (University of Chinese Academy of Sciences); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2020","Layered Na-based oxides with the general composition of NaxTMO2 (TM: transition metal) have attracted significant attention for their high compositional diversity that provides tunable electrochemical performance for electrodes in sodium-ion batteries. The various compositions bring forward complex structural chemistry that is decisive for the layered stacking structure, Na-ion conductivity, and the redox activity, potentially promising new avenues in functional material properties. In this work, we have explored the maximum Na content in P2-type layered oxides and discovered that the high-content Na in the host enhances the structural stability; moreover, it promotes the oxidation of low-valent cations to their high oxidation states (in this case Ni2+). This can be rationalized by the increased hybridization of the O(2p)-TM(3d-eg*) states, affecting both the local TM environment as well as the interactions between the NaO2 and TMO2 layers. These properties are highly beneficial for the Na storage capabilities as required for cathode materials in sodium-ion batteries. It leads to excellent Na-ion mobility, a large storage capacity (>100 mAh g-1 between 2.0-4.0 V), yet preventing the detrimental sliding of the TMO2 layers (P2-O2 structural transition), as reflected by the ultralong cycle life (3000 (dis)charge cycles demonstrated). These findings expand the horizons of high Na-content P2-type materials, providing new insights of the electronic and structural chemistry for advanced cathode materials.","","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:ded75c83-5fbe-47b9-84c8-1ce2b5a0f1a9","http://resolver.tudelft.nl/uuid:ded75c83-5fbe-47b9-84c8-1ce2b5a0f1a9","Measurements of hydrodynamics, sediment, morphology and benthos on Ameland ebb-tidal delta and lower shoreface","van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Tissier, M.F.S. (TU Delft Environmental Fluid Mechanics); de Wit, F.P. (TU Delft Environmental Fluid Mechanics); Pearson, S.G. (TU Delft Coastal Engineering; Deltares); Holzhauer, H. (Deltares; University of Twente); Gawehn, M.A. (Deltares); Antolínez, José A. Á. (TU Delft Coastal Engineering); de Vet, P.L.M. (TU Delft Coastal Engineering; Deltares); Reniers, A.J.H.M. (TU Delft Environmental Fluid Mechanics); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); den Heijer, C. (TU Delft Management Support; Data2day); Wilmink, R.J.A. (Ministry of Infrastructure and the Environment)","","2020","A large-scale field campaign was carried out on the ebb-tidal delta (ETD) of Ameland Inlet, a basin of the Wadden Sea in the Netherlands, as well as on three transects along the Dutch lower shoreface. The data have been obtained over the years 2017-2018. The most intensive campaign at the ETD of Ameland Inlet was in September 2017. With this campaign, as part of KustGenese2.0 (Coastal Genesis 2.0) and SEAWAD, we aim to gain new knowledge on the processes driving sediment transport and benthic species distribution in such a dynamic environment. These new insights will ultimately help the development of optimal strategies to nourish the Dutch coastal zone in order to prevent coastal erosion and keep up with sea level rise. The dataset obtained from the field campaign consists of (i) single-and multi-beam bathymetry; (ii) pressure, water velocity, wave statistics, turbidity, conductivity, temperature, and bedform morphology on the shoal; (iii) pressure and velocity at six back-barrier locations; (iv) bed composition and macrobenthic species from box cores and vibrocores; (v) discharge measurements through the inlet; (vi) depth and velocity from X-band radar; and (vii) meteorological data. The combination of all these measurements at the same time makes this dataset unique and enables us to investigate the interactions between sediment transport, hydrodynamics, morphology and the benthic ecosystem in more detail. The data provide opportunities to calibrate numerical models to a high level of detail. Furthermore, the open-source datasets can be used for system comparison studies. The data are publicly available at 4TU Centre for Research Data at https://doi.org/10.4121/collection:seawad (Delft University of Technology et al., 2019) and https://doi.org/10.4121/collection:kustgenese2 (Rijkswaterstaat and Deltares, 2019). The datasets are published in netCDF format and follow conventions for CF (Climate and Forecast) metadata. The http://data.4tu.nl (last access: 11 November 2020) site provides keyword searching options and maps with the geographical position of the data.","","en","journal article","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:be9aebdf-f535-4b12-b3d4-acaf01cd9c81","http://resolver.tudelft.nl/uuid:be9aebdf-f535-4b12-b3d4-acaf01cd9c81","On the application of the window of opportunity and complex network to risk analysis of process plants operations during a pandemic","Sun, Hao (China University of Petroleum (East China)); Wang, Haiqing (China University of Petroleum (East China)); Yang, M. (TU Delft Safety and Security Science); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Universiteit Antwerpen; Katholieke Universiteit Leuven)","","2020","To quantify the pandemic specific impact with respect to the risk related to the chemical industry, a novel risk analysis method is proposed. The method includes three parts. Firstly, the two types of “window of opportunity” (WO) theory is proposed to divide an accident life cycle into two parts. Then, a qualitative risk analysis is conducted based on WO theory to determine possible risk factors, evolution paths and consequences. The third part is a quantitative risk analysis based on a complex network model, integrating two types of WO. The Fuzzy set theory is introduced to calculate the failure probabilities of risk factors and the concept of risk entropy is used to represent the uncertainty. Then the Dijkstra algorithm is used to calculate the shortest path and the corresponding probability of the accident. The proposed method is applied to the SCR denitrition liquid ammonia storage and transportation system. The results show that it is a comprehensive method of quantitative risk analysis and it is applicable to risk analysis during the pandemic.","Accident evolution; Complex network; Pandemic; Risk analysis; Risk entropy; Window of opportunity","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-04-13","","","Safety and Security Science","","",""
"uuid:248cc691-d63a-4d13-83c1-3b78552f977d","http://resolver.tudelft.nl/uuid:248cc691-d63a-4d13-83c1-3b78552f977d","A spatially explicit planning approach for power systems with a high share of renewable energy sources","Wang, N. (TU Delft Energie and Industrie); Verzijlbergh, R.A. (TU Delft Energie and Industrie); Heijnen, P.W. (TU Delft Energie and Industrie); Herder, P.M. (TU Delft Energy Technology)","","2020","Variable Renewable Energy Sources (VRES) are characterized by intensive land-use and variable production. In existing optimization models that minimize the total cost of the energy system, location-specific VRES production profiles are often used to estimate VRES potential, but land-use and land cover aspects have been largely ignored. In this study, we therefore connect the literature in land cover assessment, VRES potential estimation and energy system optimization modelling by proposing a spatially explicit planning approach. This approach was applied to a case of the Netherlands to showcase its applicability and strength and to give results towards various RES targets. A baseline land-use scenario, a scenario with stricter constraints on land-use that reflects social resistance and spatial policy on wind energy and, thirdly, a scenario assuming unlimited land availability were analyzed. The baseline scenario results show the optimal geographical distribution of the generation capacities over the Netherlands. Wind energy dominates the generation mix and storage is only present at the 100% RES target. Under the strict constraints on land-use, 92% of the suitable land in the country will be deployed to place wind turbines in order to reach 100% RES share compared to 37% in the baseline case. However, the cost of electricity only increases by no more than 5 €/MWh. The unlimited land scenario highlights that the regional optimized capacities are infeasible. Apart from the useful results from the case study, the proposed approach is a first-of-a-kind contribution to the literature and provides a data-driven way to operationalize the location-specific land-use of VRES such that the role of the constraints on the land-use of VRES can be revealed and that policy-relevant results can be obtained.","Generation mix; Land-use; Optimization modelling; Spatial planning; Variable Renewable Energy Sources (VRES); VRES potential","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:5dc881f6-4feb-4524-b4b1-7adeac573476","http://resolver.tudelft.nl/uuid:5dc881f6-4feb-4524-b4b1-7adeac573476","Microwave roasting of blast furnace slag for carbon dioxide mineralization and energy analysis","Han, Zike (Sichuan University); Gao, Jianqiu (Sichuan University); Yuan, Xizhi (Sichuan University); Zhong, Yanjun (Sichuan University); Ma, Xiaodong (University of Queensland); Chen, Z. (TU Delft (OLD) MSE-3); Luo, Dongmei (Sichuan University); Wang, Ye (Sichuan University)","","2020","For both the waste treatment of large quantities of blast furnace (BF) slag and carbon dioxide (CO2) that are discharged in ironworks, mineral carbonation by BF slag was proposed in this decade. However, it has not been widely used due to its high energy consumption and low production efficiency. In this study, a microwave roasting method was employed to mineralize CO2 with BF slag, and the process parameters for the sulfation and energy consumption were investigated. A mixture of BF slag and recyclable ammonium sulfate [(NH4)2SO4] (mass ratio, 1 : 2) was roasted in a microwave tube furnace, and then leached with distilled water at a solid : liquid ratio of 1 : 3 (g mL-1). Under the optimized experiment conditions (T = 340 °C, holding time = 2 min), the best sulfation ratios of calcium (Ca), magnesium (Mg), aluminum (Al), and titanium (Ti) were 93.3%, 98.3%, 97.5%, and 80.4%, respectively. Compared with traditional roasting, the production efficiency of this process was more than 10 times higher, and the energy consumption for mineralizing 1 kg of CO2 could be reduced by 40.2% after simulation with Aspen Plus v8.8. Moreover, 236.1 kg of CO2 could be mineralized by one ton of BF slag, and a series of by-products with economic value could also be obtained. The proposed process offers an energy-efficient method with high productivity and good economy for industrial waste treatment and CO2 storage.","","en","journal article","","","","","","","","","","","(OLD) MSE-3","","",""
"uuid:5cc68b8e-6fc0-4519-b7ad-b5f03d5e63f9","http://resolver.tudelft.nl/uuid:5cc68b8e-6fc0-4519-b7ad-b5f03d5e63f9","Transient Supramolecular Hydrogels Formed by Aging-Induced Seeded Self-Assembly of Molecular Hydrogelators","Wang, Yiming (East China University of Science and Technology); Piskorz, T.K. (TU Delft ChemE/Advanced Soft Matter); Lovrak, M. (TU Delft ChemE/Advanced Soft Matter); Mendes, E. (TU Delft ChemE/Advanced Soft Matter); Guo, Xuhong (East China University of Science and Technology); Eelkema, R. (TU Delft ChemE/Advanced Soft Matter); van Esch, J.H. (TU Delft ChemE/Advanced Soft Matter)","","2020","Here, transient supramolecular hydrogels that are formed through simple aging-induced seeded self-assembly of molecular gelators are reported. In the involved molecular self-assembly system, multicomponent gelators are formed from a mixture of precursor molecules and, typically, can spontaneously self-assemble into thermodynamically more stable hydrogels through a multilevel self-sorting process. In the present work, it is surprisingly found that one of the precursor molecules is capable of self-assembling into nano-sized aggregates upon a gentle aging treatment. Importantly, these tiny aggregates can serve as seeds to force the self-assembly of gelators along a kinetically controlled pathway, leading to transient hydrogels that eventually spontaneously convert into thermodynamically more stable hydrogels over time. Such an aging-induced seeded self-assembly process is not only a new route toward synthetic out-of-equilibrium supramolecular systems, but also suggests the necessity of reporting the age of self-assembling building block solutions in other self-assembly systems.","aging; hydrogels; pathway complexity; self-assembly; supramolecular chemistry","en","journal article","","","","","","","","","","","ChemE/Advanced Soft Matter","","",""
"uuid:e408371b-7f8c-4d9d-9215-987b6a18cecc","http://resolver.tudelft.nl/uuid:e408371b-7f8c-4d9d-9215-987b6a18cecc","Performance influences of a deep high temperature fractured geothermal system","Der Kooij, R. Van (Student TU Delft); Wang, Y. (TU Delft Reservoir Engineering); Daniilidis, Alexandros (TU Delft Reservoir Engineering); Voskov, D.V. (TU Delft Reservoir Engineering)","","2020","To assess the influences of various parameters in ultra deep (>4km), high temperature, fractured geothermal systems, the system's NPV was evaluated as these parameters were varied. The examined fracture network had multiple fractures leading between the wells in a single doublet. The tested input parameters concern rock matrix parameters (permeability, porosity, thermal conductivity and heat capacity), apertures in the fracture network and cold-water injection rates. After simulation of flow, the resulting data has been used for the calculation of NPV, which provided an indication for the performance. Larger values for matrix parameters and higher fracture apertures amplified each other's positive effect they had on the NPV of the system, as they both prevented bottlenecked flow of injected water from injector to producer wells and kept the system lifetime longer by allowing injected water more time to absorb heat before reaching the production well. An optimum exists when selecting injection rate with regards to system NPV. Lower injection rates lead to lower energy production, while higher injection rates lead to shorter lifetimes. A balanced injection rate lead to a maximum NPV. More investigation into optimization of injection rate over system lifetime will prove valuable for maximizing performance.","","en","conference paper","EAGE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-05-01","","","Reservoir Engineering","","",""
"uuid:882b3d68-ab41-4a14-9043-639c11d3e546","http://resolver.tudelft.nl/uuid:882b3d68-ab41-4a14-9043-639c11d3e546","The Longitudinal Profile of a Prograding River and Its Response to Sea Level Rise","Gao, Weilun (Beijing Normal University; Ministry of Education, Shandong); Li, Dongxue (Beijing Normal University; Ministry of Education, Shandong); Wang, Zhengbing (TU Delft Coastal Engineering; Beijing Normal University; Deltares); Nardin, William (University of Maryland Center for Environmental Science); Shao, Dongdong (Beijing Normal University; Ministry of Education, Shandong); Sun, Tao (Beijing Normal University; Ministry of Education, Shandong); University, Beijing (Beijing Normal University); Cui, Baoshan (Beijing Normal University; Ministry of Education, Shandong)","","2020","River longitudinal profile, a key morphological characteristic of the river channel, is subject to river mouth progradation. Given the increasing influence of human activities and climate change on this critical downstream control, understanding its effects on the evolution of the longitudinal profile is imperative. A general theoretical framework is proposed to quantify the relevant effects, which is tested by numerical experiment and compared with field, numerical and laboratory data from the literature. The results suggest the existence of a critical ratio of accommodation space to sediment supply of approximately 0.5, above which the typical concave upward profile tends to form. Further analyses show that sea level rise tends to increase the concavity of the longitudinal profile of a river with a relatively low equilibrium bed slope and progradation rate.","","en","journal article","","","","","","","","2021-04-21","","","Coastal Engineering","","",""
"uuid:50253f83-5f1f-4bdd-9897-9b31c4a33275","http://resolver.tudelft.nl/uuid:50253f83-5f1f-4bdd-9897-9b31c4a33275","Flame-made amorphous solid acids with tunable acidity for the aqueous conversion of glucose to levulinic acid","Beh, Gein Khai (City University of Hong Kong); Wang, Chang Ting (City University of Hong Kong); Kim, Kyungduk (Institute for Basic Science); Qu, Jiangtao (University of Sydney); Cairney, Julie (University of Sydney); Ng, Yun Hau (City University of Hong Kong); An, Alicia Kyoungjin (City University of Hong Kong); Ryoo, Ryong (Korea Advanced Institute of Science and Technology; Institute for Basic Science); Urakawa, A. (TU Delft ChemE/Catalysis Engineering; Barcelona Institute of Science and Technology (BIST)); Teoh, Wey Yang (City University of Hong Kong; University of New South Wales)","","2020","Solid acids of amorphous silica-alumina (a-SA) and amorphous silica-alumina-phosphate (a-SAPO) were prepared by flame spray pyrolysis (FSP). Careful tuning of the acidity of the solid acids was enabled by capitalizing on the advantage of FSP in preserving the metal stoichiometry (i.e., Si, Al, P) in the product nanoparticles. Although the amount of acids on these non-porous solid acids is an order of magnitude lower than the well-recognized strong acidic ZSM-5 zeolite, both exhibit comparable acid strengths. The a-SA and a-SAPO were characterized by a mixture of Brønsted (B) and Lewis (L) acids, and the B/L ratios were composition-tunable. The highest B/L ratios were recorded for a-SA (Al/(Al + Si) = 0.4) and a-SAPO (Si/(P + Si) = 0.25), giving the highest yields of levulinic acid (≥40% carbon yield) from the conversion of glucose in the aqueous phase without requiring the addition of liquid acids or metal halides. Under the same conditions, the almost exclusive Brønsted acid ZSM-5 yielded only 17% levulinic acid. The FSP-made solid acid catalyst exhibited good reusability over at least 4 consecutive runs.","","en","journal article","","","","","","","","2021-11-14","","","ChemE/Catalysis Engineering","","",""
"uuid:3053e617-d6af-494b-b6d2-f7708e1fb7e7","http://resolver.tudelft.nl/uuid:3053e617-d6af-494b-b6d2-f7708e1fb7e7","Interactions between a magnon mode and a cavity photon mode mediated by traveling photons","Rao, J. W. (University of Manitoba; Lanzhou University); Wang, Y. P. (University of Manitoba); Yang, Y. (University of Manitoba); Yu, T. (TU Delft QN/Bauer Group; Kavli institute of nanoscience Delft); Gui, Y. S. (University of Manitoba); Fan, X. (Lanzhou University); Xue, D. S. (Lanzhou University); Hu, C. M. (University of Manitoba)","","2020","We systematically study the indirect interaction between a magnon mode and a cavity photon mode mediated by traveling photons of a waveguide. From a general Hamiltonian, we derive the effective coupling strength between two separated modes, and obtain the theoretical expression of the system's transmission. Accordingly, we design an experimental setup consisting of a shield cavity photon mode, a microstrip line, and a magnon system to test our theoretical predictions. From measured transmission spectra, indirect interaction, as well as mode hybridization, between two modes can be observed. All experimental observations support our theoretical predictions. In this work we clarify the mechanism of traveling photon mediated interactions between two separate modes. Even without spatial mode overlap, two separated modes can still couple with each other through their correlated dissipations into a mutual traveling photon bus. This conclusion may help us understand the recently discovered dissipative coupling effect in cavity magnonics systems. Additionally, the physics and technique developed in this work may benefit us in designing new hybrid systems based on the waveguide magnonics.","","en","journal article","","","","","","","","","","","QN/Bauer Group","","",""
"uuid:0a41eeea-0189-4632-b62d-c67492826161","http://resolver.tudelft.nl/uuid:0a41eeea-0189-4632-b62d-c67492826161","Unsupervised anomaly detection in railway catenary condition monitoring using autoencoders","Wang, H. (TU Delft Railway Engineering)","","2020","The condition monitoring of railway infrastructures is collecting big data for intelligent asset management. Making the most of the big data is a critical challenge facing the railway industry. This study focuses on one of the main railway infrastructures, namely the catenary (overhead line) system that transmits power to trains. To facilitate the effective usage of catenary condition monitoring data, this study proposes an unsupervised anomaly detection approach as a pre-processing measure. The approach trains autoencoders to reduce the dimensionality of multisensor data and generate discriminative features between healthy and anomalous data. By testing the reconstruction errors using the trained autoencoders, anomalous data that indicate potential defects of catenary can be identified without prior information and human intervention. A case study on a section of high-speed railway catenary in China shows that the approach can automatically distinguish between healthy and anomalous data. The output anomalous data can save a considerable amount of computation time and manpower in further interpretations aiming to pinpoint defects.","anomaly detection; autoencoders; condition monitoring; railway catenary; unsupervised learning","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-05-18","","","Railway Engineering","","",""
"uuid:fa43da13-6ee9-4a83-9060-8ec4a634e7fb","http://resolver.tudelft.nl/uuid:fa43da13-6ee9-4a83-9060-8ec4a634e7fb","The residual stress characteristics and mechanical behavior of shot peened fiber metal laminates based on the aluminium-lithium alloy","Li, H. (TU Delft Structural Integrity & Composites; Nanjing Institute of Technology); Wang, Hao (Nanjing University of Aeronautics and Astronautics); Alderliesten, R.C. (TU Delft Structural Integrity & Composites); Xiang, Junxian (Nanjing University of Aeronautics and Astronautics); Lin, Yanyan (Nanjing University of Aeronautics and Astronautics); Xu, Yingmei (Nanjing University of Aeronautics and Astronautics); Zhao, Haidan (Nanjing Institute of Technology); Tao, Jie (Nanjing University of Aeronautics and Astronautics)","","2020","The effect of shot peen forming on the mechanical behavior of fiber metal laminates (FMLs) based on aluminium-lithium alloy was investigated to reveal the strengthening mechanism and to dispel the suspicion that shot peen forming may result in the performance deterioration of FMLs. The interlaminar, static strength and fatigue properties of shot peened FMLs were investigated. The residual stress characteristics of the shot peened FMLs was also involved with finite element analysis to help understanding the unique mechanical behavior. The results indicated that shot peening caused non-negligible work hardening in external metal layers, which increased the tensile strength of the laminates. But the work hardening did not deteriorate the elongations of FMLs since the failure still dominated by the limitation of fiber failure strain. Moreover, two yield stages were observed in the tensile tests of shot peened FMLs owing to the great difference in stress states between external and internal metal layers. The compressive stress introduced by shot peening effectively improved the FCG properties of FMLs. All metal layers possessed similar crack propagation rates despite that the stress difference was up to 300 MPa, which indicated that the fiber bridging effect still dominated the FCG of FMLs.","Aluminum-lithium alloy; Fiber metal laminates; Mechanical behavior; Residual stress; Shot peen forming","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-06-04","","","Structural Integrity & Composites","","",""
"uuid:79054b6f-b10c-4062-b142-ce5f94561e96","http://resolver.tudelft.nl/uuid:79054b6f-b10c-4062-b142-ce5f94561e96","A study of graphene nanoribbon-based gate performance robustness under temperature variations","Jiang, Y. (TU Delft Computer Engineering); Cucu Laurenciu, N. (TU Delft Computer Engineering); Wang, H. (TU Delft Computer Engineering); Cotofana, S.D. (TU Delft Computer Engineering)","","2020","As CMOS scaling is reaching its limits, high power density and leakage, low reliability, and increasing IC production costs are prompting for developing new materials, devices, architectures, and computation paradigms. Additionally, temperature variations have a significant impact on devices and circuits reliability and performance. Graphene's remarkable properties make it a promising post Silicon frontrunner for carbon-based nanoelectronics. While for CMOS gates temperature effects have been largely investigated, for gates implemented with atomic-level Graphene Nanoribbons (GNRs), such effects have not been explored. This paper presents the results of such an analysis performed on a set of GNR-based Boolean gates by varying the operation temperature within the military range, i.e., -55°C to 125°C, and evaluating by means of SPICE simulations gate output signal integrity, propagation delay, and power consumption. Our simulation results reveal that GNR-based gates are robust with respect to temperature variation, e.g., 5.2% and 5.3% maximum variations of NAND output logic '1' (VOH) and logic '0' ($V$OL) voltage levels, respectively. Moreover, even in the worst condition GNR-based gates outperform CMOS FinFET 7nm counterparts, e.g., 1.6× smaller delay and 185× less power consumption for the INV case, which is strengthening their great potential as basic building blocks for future reliable, low-power, nanoscale carbon-based electronics.","Boolean Gates; Carbon Nanoelectronics; GNR; Graphene; NEGF; Phonon Scattering; Reliability; Temperature Effects","en","conference paper","IEEE","","","","","Accepted author manuscript","","","","","Computer Engineering","","",""
"uuid:99bb5226-7e23-4b1f-a8cc-fcb62472fa79","http://resolver.tudelft.nl/uuid:99bb5226-7e23-4b1f-a8cc-fcb62472fa79","Ultra-Compact, Entirely Graphene-based Nonlinear Leaky Integrate-and-Fire Spiking Neuron","Wang, H. (TU Delft Computer Engineering); Cucu Laurenciu, N. (TU Delft Computer Engineering); Jiang, Y. (TU Delft Computer Engineering); Cotofana, S.D. (TU Delft Computer Engineering)","","2020","Designing and implementing artificial neuromorphic systems, which can provide biocompatible interfacing, or the human brain akin ability to efficiently process information, is paramount to the understanding of the human brain complex functionality. Energy-efficient, low-area, and biocompatible artificial neurons are key ubiquitous components of any large scale neural systems. Previous CMOS-based neurons implementations suffer from scalability drawbacks and cannot naturally mimic the analog behavior. Memristor and phase-changed neurons have variability-induced instability drawbacks, and usually rely on additional CMOS circuitry. However, graphene, despite its ballistic transport, inherently analog nature, and biocompatibility, which provide natural support for biologically plausible neuron implementations has only been considered for Boolean logic implementations. In this paper, we propose an ultra-compact, all graphene-based nonlinear Leaky Integrate-and-Fire spiking neuron. By means of SPICE simulations, we validate its basic functionality and investigate the output spikes response under stochastic noisy input spike trains with a variable firing rate, from 20 to 200 spikes per second. Simulation results indicate neuron robustness to noisy scenarios, and neuronal output firing regularity. The small area and the low energy consumption, due to 200mV supply voltage operation, can benefit the implementation of large scale neural networks, and the biologically plausible operating conditions (e.g., 2ms and 100mV spike duration and amplitude), can promote the interfacebility of graphene-based artificial neurons with biological counterparts.","Neuromorphic Computing; Integrate-And-Fire Neuron; Graphene; GNR","en","conference paper","IEEE","","","","","Virtual/online event due to COVID-19","","","","","Computer Engineering","","",""
"uuid:e837f321-fa37-4065-a3dd-d43fdc130982","http://resolver.tudelft.nl/uuid:e837f321-fa37-4065-a3dd-d43fdc130982","User Scheduling and Antenna Topology in Dense Massive MIMO Networks: An Experimental Study","Wang, Cheng Ming (Katholieke Universiteit Leuven); Wang, Q. (TU Delft Embedded Systems); Gaber, Abdo (National Instruments); Guevara, Andrea P. (Katholieke Universiteit Leuven); Pollin, Sofie (Katholieke Universiteit Leuven)","","2020","A massive MIMO network can serve ten's of users simultaneously. However, in dense scenarios the users are potentially closely-spaced, potentially resulting in substantial inter-user interference. Scheduling can overcome this by selecting the users that lead to the highest combined spectral efficiency. As scheduling comes with a significant pilot overhead, an alternative strategy could minimize user correlation by distributing the antenna elements in space. In this paper, we propose a comprehensive system study including antenna topology and distribution, user scheduling and pilot overhead reduction. Our user scheduling and pilot reduction algorithms are evaluated using system level simulations relying on indoor line-of-sight channel measurements from a 64 antenna base station at 2.61GHz. To have a thorough evaluation of the proposed algorithm, we consider four different antenna topologies, including co-located and distributed placement of the base station arrays. Our evaluation shows that in a conference room with 64 densely deployed users, our proposed low complexity algorithm can improve the spectral efficiency by at least 14% compared to random user selection with the best antenna distribution strategy. Finally, our results show that by relying on channel hardening, we reduce the pilot overhead by 3.2 \times.","dense networks; distributed antenna arrays; Massive MIMO networks; testbed measurements; user scheduling","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-08-17","","","Embedded Systems","","",""
"uuid:580a2bfa-36fe-4f57-966d-35d0c3ec640c","http://resolver.tudelft.nl/uuid:580a2bfa-36fe-4f57-966d-35d0c3ec640c","Low-Complexity Gridless 2D Harmonic Retrieval via Decoupled-ANM Covariance Reconstruction","Zhang, Yu (Nanjing University of Aeronautics and Astronautics); Wang, Yue (George Mason University); Tian, Zhi (George Mason University); Leus, G.J.T. (TU Delft Signal Processing Systems); Zhang, Gong (Nanjing University of Aeronautics and Astronautics)","","2020","This paper aims at developing low-complexity solutions for super-resolution two-dimensional (2D) harmonic retrieval via covariance reconstruction. Given the collected sample covariance, a novel gridless compressed sensing approach is designed based on the atomic norm minimization (ANM) technique. The key is to perform a redundancy reduction (RR) transformation that effectively reduces the large problem size at hand, without loss of useful frequency information. For uncorrelated sources, the transformed 2D covariance matrices in the RR domain retain a salient structure, which permits a sparse representation over a matrix-form atom set with decoupled 1D frequency components. Accordingly, the decoupled ANM (DANM) framework can be applied for super-resolution 2D frequency estimation, at low computational complexity on the same order of the 1D case. An analysis of the complexity reduction of the proposed RR-D-ANM compared with benchmark methods is provided as well, which is verified by our simulation results","2D harmonic retrieval; Covariance reconstruction; D-ANM; Low complexity; RR transformation","en","conference paper","Eurasip","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-08-29","","","Signal Processing Systems","","",""
"uuid:34ee3035-f4e7-4356-9ee0-63436187c020","http://resolver.tudelft.nl/uuid:34ee3035-f4e7-4356-9ee0-63436187c020","Effect of Structural Defects and Impurities on the Excited State Dynamics of 2D BA2PbI4 Perovskite","Gelvez Rueda, M.C. (TU Delft ChemE/Opto-electronic Materials); Peeters, Sicco (Student TU Delft); Wang, Peng Cheng (Student TU Delft); Felter, K.M. (TU Delft ChemE/Opto-electronic Materials); Grozema, F.C. (TU Delft ChemE/Opto-electronic Materials)","","2020","In this work, we show that the quality of the precursor and the thin film preparation strongly affect the optoelectronic properties of the 2D perovskite BA2PbI4. 2D perovskites with alkylammonium organic cations such as butylammonium (BA) are relatively soft structures that exhibit large dynamic disorder and phase variations. Here we show, by a variety of spectroscopy techniques (steady state absorption, photoluminescence and ultrafast transient absorption), that at temperatures below the phase transition (253 K) the material exhibits excitonic features from the room temperature phase (due to incomplete structural transition) and a broadband emission at 560–600 nm (due to self-trapped excitons) with varied relative intensities depending on the precursors and processing conditions. This suggests that the processing conditions have a large influence on the crystallization and introduction of extrinsic defect impurities directly affecting the optoelectronic properties. Making absolute statements about the properties of BA2PbI4 requires improved control over the materials thin film deposition and a better understanding of the role of the lattice vibrational dynamics and extrinsic defects on the exciton dynamics.","2D perovskites; femtosecond transient absorption; phase transitions; photoluminescence; thin films","en","journal article","","","","","","","","","","","ChemE/Opto-electronic Materials","","",""
"uuid:b7c82d1f-59a8-4bff-bd83-a8c90e7e04b5","http://resolver.tudelft.nl/uuid:b7c82d1f-59a8-4bff-bd83-a8c90e7e04b5","Wave Controls on Deltaic Shoreline‐Channel Morphodynamics: Insights From a Coupled Model","Gao, Weilun (Beijing Normal University; Ministry of Education); Nienhuis, Jaap (Universiteit Utrecht); Nardin, William (University of Maryland Center for Environmental Science); Wang, Zhengbing (TU Delft Coastal Engineering; Beijing Normal University; Deltares); Shao, Dongdong (Beijing Normal University; Ministry of Education); Sun, Tao (Beijing Normal University; Ministry of Education); Cui, Baoshan (Beijing Normal University; Ministry of Education)","","2020","It is widely recognized that waves inhibit river mouth progradation and reduce the avulsion
timescale of deltaic channels. Nevertheless, those effects may not apply to downdrift‐deflected channels. In this study, we developed a coupled model to explore the effects of wave climate asymmetry and alongshore sediment bypassing on shoreline‐channel morphodynamics. The shoreline position and channel trajectory are simulated using a “shoreline” module which drives the evolution of the river profile in a “channel” module by updating the position of river mouth boundary, whereas the channel module provides the sediment load to river mouth for the “shoreline” module. The numerical results show that regional alongshore sediment transport driven by an asymmetric wave climate can enhance the progradation of deltaic channels if sediment bypassing of the river mouth is limited, which is different from the common assumption that waves inhibit delta progradation. As such, waves can have a trade‐off effect on river mouth progradation that can further influence riverbed aggradation and channel avulsion. This trade‐off effect of waves is dictated by the net alongshore sediment transport, sediment bypassing at the river mouth, and wave diffusivity. Based on the numerical results, we further propose a dimensionless parameter that includes fluvial and alongshore sediment supply relative to wave diffusivity to predict the progradation and aggradation rates and avulsion timescale of deltaic channels. The improved understanding of progradation, aggradation, and avulsion timescale of deltaic channels has important implications for
engineering and predicting deltaic wetland creation, particularly under changing water and sediment input to deltaic systems.","","en","journal article","","","","","","","","2021-02-03","","","Coastal Engineering","","",""
"uuid:9a4ef3ed-66ae-489a-9f4c-b6de77b125b1","http://resolver.tudelft.nl/uuid:9a4ef3ed-66ae-489a-9f4c-b6de77b125b1","Theoretical study on regular reflection of shock wave-boundary layer interactions","Xue, S. (TU Delft Aerodynamics; Nanjing University of Aeronautics and Astronautics; Key Laboratory of Unsteady Aerodynamics and Flow Control); Schrijer, F.F.J. (TU Delft Aerodynamics); van Oudheusden, B.W. (TU Delft Aerodynamics); Wang, Chengpeng (Nanjing University of Aeronautics and Astronautics); Shi, Zhiwei (Nanjing University of Aeronautics and Astronautics); Cheng, Keming (Nanjing University of Aeronautics and Astronautics)","","2020","In this paper the configurations of shock wave-boundary layer interactions (SWBLI) are studied theoretically and experimentally in Mach number 2 and 2.5 flows on test models with various wedge angles ranging from to. The proposed theoretical method couples the free interaction theory (FIT) with the minimum entropy production (MEP) principle to predict the appearance of separation shock, resulting in convex, straight and concave separation shock waves according to different solution combinations, which agree well with current experiments. Additionally, several influences on SWBLI are studied experimentally, in which the parameters related to theoretical solutions are found mostly determining the flow configuration, and SWBLI is much more sensitive to incident shock strength than incoming flow properties. Separation could be suppressed by incident shock when the MEP solution is smaller than the FIT, while it could be intensified when the MEP solution is larger than FIT; by contrast, the effects of separation position and model mounting height could be very weak.","boundary layer separation; high-speed flow; shock waves","en","journal article","","","","","","","","","","","Aerodynamics","","",""
"uuid:a5ab144e-5f12-4fff-9a98-119bfced7932","http://resolver.tudelft.nl/uuid:a5ab144e-5f12-4fff-9a98-119bfced7932","A deep-learning method for radar micro-doppler spectrogram restoration","He, Yuan (Beijing University of Posts and Telecommunications); Li, Xinyu (Beijing University of Posts and Telecommunications); Li, Runlong (Beijing University of Posts and Telecommunications); Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Jing, Xiaojun (Beijing University of Posts and Telecommunications)","","2020","Radio frequency interference, which makes it difficult to produce high-quality radar spectrograms, is a major issue for micro-Doppler-based human activity recognition (HAR). In this paper, we propose a deep-learning-based method to detect and cut out the interference in spectrograms. Then, we restore the spectrograms in the cut-out region. First, a fully convolutional neural network (FCN) is employed to detect and remove the interference. Then, a coarse-to-fine generative adversarial network (GAN) is proposed to restore the part of the spectrogram that is affected by the interferences. The simulated motion capture (MOCAP) spectrograms and the measured radar spectrograms with interference are used to verify the proposed method. Experimental results from both qualitative and quantitative perspectives show that the proposed method can mitigate the interference and restore high-quality radar spectrograms. Furthermore, the comparison experiments also demonstrate the efficiency of the proposed approach.","Fully convolutional network; Generative adversarial network; Image restoration; Radar micro-doppler spectrogram","en","journal article","","","","","","","","","","","Microwave Sensing, Signals & Systems","","",""
"uuid:82ee449b-45a2-4e1f-8d89-61470ff912be","http://resolver.tudelft.nl/uuid:82ee449b-45a2-4e1f-8d89-61470ff912be","A Hierarchical Model-Based Optimization Control Approach for Cooperative Merging by Connected Automated Vehicles","Chen, N. (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning); Alkim, Tom (Ministry of Infrastructure and the Environment); Wang, M. (TU Delft Transport and Planning)","","2020","Gap selection and dynamic speed profiles of interacting vehicles at on-ramps affect the safety and efficiency of highway merging sections. This paper puts forward a hierarchical control approach for Connected Automated Vehicles (CAVs) to achieve efficient and safe merging operations. A tactical layer controller employs a second-order car-following model with a cooperative merging mode to represent a cooperative merging process and generates an optimal vehicle merging sequence and time instants when on-ramp CAVs start to adapt their speeds and positions to prepare merging into the target gaps respectively. An operational layer controller is designed based on Model Predictive Control (MPC). It uses a third-order vehicle dynamics model and optimizes desired accelerations for CAVs and the time instants when the on-ramp CAVs initiate the lane-changing executions respectively. Both the tactical layer controller and operational layer controller derive their control commands by minimizing an objective function for different time horizons. The objective function penalizes deviations of CAVs' inter-vehicle gaps to their desired values, relative speeds to their direct predecessors, and actual or desired accelerations, subject to constraints on velocities, actual or desired accelerations, and inter-vehicle gaps. The performance of the proposed hierarchical control framework and a benchmark on-ramp merging method using a first-in-first-out rule to determine the merging sequence is demonstrated under 135 scenarios with different initial conditions, desired time gap settings, and numbers of on-ramp vehicles. The experimental results show the superiority of the hierarchical control approach.","Connected automated vehicles (CAVs); merging sequence; on-ramp merging; optimization control","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-01-21","","","Transport and Planning","","",""
"uuid:7f0ae54b-520f-43b7-84a1-839559423792","http://resolver.tudelft.nl/uuid:7f0ae54b-520f-43b7-84a1-839559423792","Hypericin: Source, Determination, Separation, and Properties","Zhang, Jie (Chongqing Technology and Business University); Gao, Ling (Chongqing Technology and Business University); Hu, Jie (Chongqing Technology and Business University); Wang, Chongjun (Chongqing Technology and Business University); Hagedoorn, P.L. (TU Delft BT/Biocatalysis); Li, Ning (Chongqing Technology and Business University); Zhou, Xing (Chongqing Academy of Chinese Materia Medica, Chongqing)","","2020","Hypericin is a naturally occurring compound synthesized by certain species of the genus Hypericum, with various pharmacological effects. It is used as a natural photosensitizing agent with great potential in photodynamic therapy. This review discusses the latest results about the biosynthetic pathways and chemical synthetic routes to obtain hypericin. Although many analysis methods can be used for the determination of hypericin purity, HPLC has become the method of choice due to its fast and sensitive analyses. The extraction and purification of hypericin are also described. Hypericin can be used as a photosensitizer due to a large and active π-electron conjugated system in its structure. Medical applications of hypericin are not easy due to several unsolved practical problems, which include hypericin phototoxicity, poor solubility in water, and extreme sensitivity to light, heat, and pH.","extraction; Hypericin; photosensitivity; solubility; stability; synthesis","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:cff87d8a-3363-431f-a23d-8288833511ca","http://resolver.tudelft.nl/uuid:cff87d8a-3363-431f-a23d-8288833511ca","Characterization of a multi-pinhole molecular breast tomosynthesis scanner","Wang, B. (TU Delft RST/Biomedical Imaging); van Roosmalen, J. (TU Delft RST/Biomedical Imaging); Kreuger, R. (TU Delft RST/Technici Pool); Huizenga, J. (TU Delft RST/Technici Pool); Beekman, F.J. (TU Delft RST/Biomedical Imaging; University Medical Center Utrecht; MILabs B.V.); Goorden, M.C. (TU Delft RST/Biomedical Imaging)","","2020","In recent years, breast imaging using radiolabelled molecules has attracted significant interest. Our group has proposed a multi-pinhole molecular breast tomosynthesis (MP-MBT) scanner to obtain 3D functional molecular breast images at high resolutions. After conducting extensive optimisation studies using simulations, we here present a first prototype of MP-MBT and evaluate its performance using physical phantoms. The MP-MBT design is based on two opposing gamma cameras that can image a lightly compressed pendant breast. Each gamma camera consists of a 250 × 150 mm2 detector equipped with a collimator with multiple pinholes focusing on a line. The NaI(Tl) gamma detector is a customised design with 3.5 mm intrinsic spatial resolution and high spatial linearity near the edges due to a novel light-guide geometry and the use of square PMTs. A volume-of-interest is scanned by translating the collimator and gamma detector together in a sequence that optimises count yield from the scan region. Derenzo phantom images showed that the system can reach 3.5 mm resolution for a clinically realistic 99mTc activity concentration in an 11-minute scan, while in breast phantoms the smallest spheres visible were 6 mm in diameter for the same scan time. To conclude, the experimental results of the novel MP-MBT scanner showed that the setup had sub-centimetre breast tumour detection capability which might facilitate 3D molecular breast cancer imaging in the future.","Breast imaging; Gamma camera; Pinhole collimator; SPECT","en","journal article","","","","","","","","","","","RST/Biomedical Imaging","","",""
"uuid:c58914b2-04a2-4d63-a846-72f46df95cd7","http://resolver.tudelft.nl/uuid:c58914b2-04a2-4d63-a846-72f46df95cd7","Design Considerations and Short-Circuit Characteristics of Fully Superconducting Wind Turbine Generators","Liu, Dong (Hohai University); Hasanov, Urfan (Hohai University); Ye, Changqing (Hohai University); Gou, Xiaofan (Hohai University); Wang, X. (TU Delft Transport Engineering and Logistics)","","2020","Compared with partially superconducting generators, fully superconducting generators (F-SCGs) can further increase the torque density in large direct-drive wind turbine applications. Design trends of F-SCGs intend to increase the electrical loading by applying superconducting wires and boost the current density in the armature winding to meet the critical current density with a safety margin. High currents may cause a low power factor and require the power electronic converter to have a much larger capacity. In an F-SCG, furthermore, torques could be too high, and field and armature currents may exceed the critical currents during a generator short circuit. This paper studies the design of a 20 MW F-SCG with consideration of the control strategy and the power factor, and then evaluates the short circuit characteristic of the F-SCG. The results analysis shows that a capacitive load control should be adopted to avoid a significant drop in the power factor and to make full use of the current-carrying capability of superconductors. An I_{d} = 0 control can also be used with a medium current level. During the short circuit, the negative side is that the phase currents exceed the critical currents and cause quenches. The positive side is that the field currents stay below the critical currents and the torques do not exceed the mechanical limitation of three times the rated torque.","Fully superconducting generator; power factor; short circuit; superconducting armature; wind turbine","en","conference paper","IEEE","","","","","Accepted Author Manuscript","","","","","Transport Engineering and Logistics","","",""
"uuid:8f484b95-e0e9-4414-8f03-63ff5b510da2","http://resolver.tudelft.nl/uuid:8f484b95-e0e9-4414-8f03-63ff5b510da2","Influence of Texture Structure on the Perception of Color Composition","Wang, Jing (Bloomburg LP, New York); Zujovic, Jana (Google LLC); Choi, June (Accenture); Chakraborty, Basabdutta (Amway, Ada); van Egmond, R. (TU Delft Human Information Communication Design); de Ridder, H. (TU Delft Human Information Communication Design); Pappas, Thrasyvoulos N. (Northwestern University)","","2020","The authors explore the influence of the structure of a texture image on the perception of its color composition through a series of psychophysical studies. They estimate the color composition of a texture by extracting its dominant colors and the associated percentages. They then synthesize new textures with the same color composition but different geometric structural patterns. They conduct empirical studies in the form of two-alternative forced choice tests to determine the influence of two structural factors, pattern scale and shape, on the perceived amount of target color. The results of their studies indicate that (a) participants are able to consistently assess differences in color composition for textures of similar shape and scale, and (b) the perception of color composition is nonveridical. Pattern scale and shape have a strong influence on perceived color composition: the larger the scale, the higher the perceived amount of the target color, and the more elongated the shape, the lower the perceived amount of the target color. The authors also present a simple model that is consistent with the results of their empirical studies by accounting for the reduced visibility of the pixels near the color boundaries. In addition to a better understanding of human perception of color composition, their findings will contribute to the development of color texture similarity metrics.","OA-Fund TU Delft","en","journal article","","","","","","","","","","","Human Information Communication Design","","",""
"uuid:b77546b5-4ed6-4cfb-bc7b-c7cd47075c1e","http://resolver.tudelft.nl/uuid:b77546b5-4ed6-4cfb-bc7b-c7cd47075c1e","Rational design of layered oxide materials for sodium-ion batteries","Zhao, Chenglong (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Wang, Qidi (Tsinghua University; School of Materials Science and Engineering); Yao, Zhenpeng (Harvard University); Wang, Jianlin (Chinese Academy of Sciences); Sánchez-Lengeling, Benjamín (Harvard University); Ding, Feixiang (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Qi, Xingguo (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Lu, Yaxiang (University of Chinese Academy of Sciences; Chinese Academy of Sciences); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2020","Sodium-ion batteries have captured widespread attention for grid-scale energy storage owing to the natural abundance of sodium. The performance of such batteries is limited by available electrode materials, especially for sodium-ion layered oxides, motivating the exploration of high compositional diversity. How the composition determines the structural chemistry is decisive for the electrochemical performance but very challenging to predict, especially for complex compositions. We introduce the ""cationic potential"" that captures the key interactions of layered materials and makes it possible to predict the stacking structures. This is demonstrated through the rational design and preparation of layered electrode materials with improved performance. As the stacking structure determines the functional properties, this methodology offers a solution toward the design of alkali metal layered oxides.","","en","journal article","","","","","","Accepted Author Manuscript","","2021-06-06","","","RST/Storage of Electrochemical Energy","","",""
"uuid:8cbba7af-7c18-4576-a18b-c58dbfebeb61","http://resolver.tudelft.nl/uuid:8cbba7af-7c18-4576-a18b-c58dbfebeb61","Action-driven Reinforcement Learning for Improving Localization of Brace Sleeve in Railway Catenary","Zhong, J. (Southwest Jiaotong University); Liu, Zhigang (Southwest Jiaotong University); Wang, H. (TU Delft Railway Engineering); Liu, W. (Southwest Jiaotong University); Yang, Cheng (Southwest Jiaotong University); Nunez, Alfredo (TU Delft Railway Engineering)","","2020","Brace Sleeve (BS) plays an essential role in connecting and fixing cantilevers of railway catenary systems. It needs to be monitored to ensure the safety of railway operations. In the literature, image processing techniques that can localize BSs from inspection images are proposed. However, the boxes produced by existing methods can contain incomplete and/or irrelevant information of the localized BS. This reduces the accuracy of BS condition diagnosis in further analyses. To address this issue, this paper proposes the use of an action-driven reinforcement learning method that adopts the coarse-localized box provided by existing methods, and finds the movements needed for the box to approach to the true BS position automatically and accurately. In contrast to the existing methods that predict one position of the box containing a BS, the proposed action-driven method sees the localization problem as a dynamic position searching process. The localization of BS is achieved by following a sequence of actions, which in this paper are position-moving (up, down, left or right), scale-changing (scale up or scale down) and shape-changing (fatter or taller). The policy of selecting dynamic actions is obtained by reinforcement learning. In the experiment, the proposed method is tested with real-life images taken from a high-speed line in China. The results show that our method can effectively improve the localization accuracy for 81.8% of the analyzed images. We also analyze cases where the method did not improve the localization and suggest further research lines.","action-driven learning; brace sleeve; localization; railway catenary; reinforcement learning","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-05-24","","","Railway Engineering","","",""
"uuid:5eaf7aa6-4008-4a61-af8a-0cb8739e0ee2","http://resolver.tudelft.nl/uuid:5eaf7aa6-4008-4a61-af8a-0cb8739e0ee2","Control Design, Stability Analysis, and Traffic Flow Implications for Cooperative Adaptive Cruise Control Systems with Compensation of Communication Delay","Zhang, Y. (TU Delft Transport and Planning; Tongji University); Bai, Yu (Tongji University); Hu, Jia (Tongji University); Wang, M. (TU Delft Transport and Planning)","","2020","Communication delay is detrimental to the performance of cooperative adaptive cruise control (CACC) systems. In this paper, we incorporate communication delay explicitly into control design and propose a delay-compensating CACC. In this new CACC system, the semi-constant time gap (Semi-CTG) policy, which is modified on the basis of the widely-used CTG policy, is employed by a linear feedback control law to regulate the spacing error. The semi-CTG policy uses historical information of the predecessor instead of its current information. By doing so, communication delay is fully compensated, which leads to better stability performance. Three stability properties—local stability, string stability, and traffic flow stability—are analyzed. The local stability and string stability of the proposed CACC system are guaranteed with the desired time gap as small as the communication delay. Both theoretical analysis and simulation results show that the delay-compensating CACC has better string stability and traffic flow stability than the widely-used CACC system. Furthermore, the proposed CACC system also shows the potential for improving traffic throughput and fuel efficiency. Robustness of the proposed system against uncertainties of sensor delay and vehicle dynamics is also verified with simulation.","","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:44b6c8b4-3716-4cca-bf4c-9671a86ba266","http://resolver.tudelft.nl/uuid:44b6c8b4-3716-4cca-bf4c-9671a86ba266","Modeling the decentralized energy investment and operation in the prosumer era: a systematic review","Wang, N. (TU Delft Energie and Industrie); Verzijlbergh, R.A. (TU Delft Energie and Industrie); Heijnen, P.W. (TU Delft Energie and Industrie); Herder, P.M. (TU Delft ChemE/Chemical Engineering)","","2020","This paper reviews the literature on the modeling approaches on decentralized energy investment and operation in the prosumer era. The study has several contributions. Firstly, it adds investment models into the review which have not been previously reviewed for decentralized energy modeling. Secondly, a modeling framework consisting of four building blocks is proposed that covers model conceptualization and model operationalization. Thirdly, the relationship between trading mechanisms and model methods is revealed using four evaluation criteria. Furthermore, by reviewing the papers, several trends in the literature are found. Operational models and local markets have been extensively studied, while wholesale market integration and investment models lack scientific attention. Among different trading mechanisms, the usage of bilateral contracts is most commonly seen. Lastly, optimization models significantly outnumber other model methods, and then it follows that their pitfalls such as the scalability of the model and the existence of stable outcomes need to be further addressed in future research.","Investment; Market design; Modeling; Operation; Prosumers; Review","en","conference paper","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-04-10","","ChemE/Chemical Engineering","Energie and Industrie","","",""
"uuid:8e403bdc-de3d-47b0-8523-6d0eaad800fa","http://resolver.tudelft.nl/uuid:8e403bdc-de3d-47b0-8523-6d0eaad800fa","Empirics and models of fragmented lane changes","Mullakkal-Babu, F.A. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning); Happee, R. (TU Delft Intelligent Vehicles)","","2020","Existing microscopic traffic models represent the lane-changing maneuver as a continuous and uninterrupted lateral movement of the vehicle from its original to the target lane. We term this representation as Continuous Lane-Changing (CLC). Recent empirical studies find that not all lane-changing maneuvers are continuous; the lane-changer may pause its lateral movement during the maneuver resulting in a Fragmented Lane-Changing (FLC). We analysed a set of 1064 lane changes from NGSIM dataset which contains 270 FLCs. In comparison to a CLC, this study investigates the distinction of an FLC in terms of its execution and its effects on neighbouring vehicles. We find that during the execution of an FLC, the lane-changer exhibits distinct kinematics and takes a longer duration to complete the lane-changing. We propose a trajectory model to describe the lateral kinematics during an FLC. Additionally, we find that the FLC induces a distinct effect on the follower in the target lane, and propose a model to describe the transient behavior of the target-follower during an FLC. The modelling results suggest that the accuracy of traffic flow models can be improved by deploying lane change execution and impact models that are specific to FLC and CLC. Besides, this study identifies a set of factors that might be related to the decision-making process behind FLC: an average driver executes an FLC when the preceding and following vehicles in the target lane are slower, and when the follower in the target lane is closer than those observed during the onset of a CLC. Our findings suggest that FLC is motivated by an increased necessity to change lane such as during a mandatory lane change.","Lane-changing trajectory; fragmented lane change; lane-changing execution; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:a3271ee7-df7b-46af-a09c-5a2288fd563f","http://resolver.tudelft.nl/uuid:a3271ee7-df7b-46af-a09c-5a2288fd563f","Incremental Nonlinear Fault-Tolerant Control of a Quadrotor With Complete Loss of Two Opposing Rotors","Sun, Sihao (Student TU Delft); Wang, Xuerui (TU Delft Aerospace Structures & Computational Mechanics); Chu, Q. P. (TU Delft Control & Simulation); de Visser, C.C. (TU Delft Control & Simulation)","","2020","In order to further expand the flight envelope of quadrotors under actuator failures, we design a nonlinear sensor-based fault-tolerant controller to stabilize a quadrotor with failure of two opposing rotors in the high-speed flight condition (>8 m/s). The incremental nonlinear dynamic inversion approach which excels in handling model uncertainties is adopted to compensate for the significant unknown aerodynamic effects. The internal dynamics of such an underactuated system have been analyzed, and subsequently stabilized by redefining the control output. The proposed method can be generalized to control a quadrotor under single-rotor-failure and nominal conditions. For validation, flight tests have been carried out in a large-scale open jet wind tunnel. The position of a damaged quadrotor can be controlled in the presence of significant wind disturbances. A linear quadratic regulator approach from the literature has been compared to demonstrate the advantages of the proposed nonlinear method in the windy and high-speed flight condition.","Air safety; fault tolerant control; nonlinear control systems; unmanned aerial vehicles; Uncertainty; Attitude control; Atmospheric modeling; Rotors; Aerodynamics; Robustness; Nonlinear dynamical systems","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-05","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:e35012b8-4514-46b0-969a-7d15b485916d","http://resolver.tudelft.nl/uuid:e35012b8-4514-46b0-969a-7d15b485916d","Comparative Safety Assessment of Automated Driving Strategies at Highway Merges in Mixed Traffic","Mullakkal-Babu, F.A. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning); Happee, R. (TU Delft Intelligent Vehicles)","","2020","We present a simulation-based approach to assess the safety impacts of vehicles equipped with Automated Driving Systems (ADS) in mixed traffic with Human-driven Vehicles (HV). Specifically, we compare two generic longitudinal strategies of ADS to handle a cut-in: Reactive ADS acting only when the cut-in vehicle crosses the target lane boundary, and Predictive ADS acting at the onset of the cut-in manoeuvre. We identify their distinctive effects on the traffic safety under cut-in maneuvers of adjacent human-driven vehicles at highway merges. We employ a microscopic traffic flow simulator that describes the lane changing process with high detail, accounting for the vehicle interaction and consequent trajectory updates. These high-resolution trajectories are post-processed to estimate a set of relevant surrogate measures of safety. By analyzing these measures, we find that the predictive ADS significantly outperforms the reactive ADS in aspects such as temporal proximity to crash, expected crash severity and the driving risk (combining the two aspects), and the number of aborted lane changes by HV. The negative safety impact of reactive ADS becomes prominent at penetration rate > 10%. The major difference between the two ADS approaches appears in the dynamics of risk during the lane changing. When a vehicle cuts in ahead of Reactive ADS, the risk peaks approximately halfway through the maneuver; whereas with Predictive ADS the risk remains marginal throughout. This work demonstrates the potential of simulation-based safety assessment to differentiate the safety impacts of automation functionalities at an early stage of product development.","Traffic safety; automated driving; microscopic simulation; surrogate measure of safety; tactical decisions.","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-06-03","","","Transport and Planning","","",""
"uuid:3fdef35c-3548-4298-820a-935769098224","http://resolver.tudelft.nl/uuid:3fdef35c-3548-4298-820a-935769098224","S2IGAN: Speech-to-Image Generation via Adversarial Learning","Wang, X. (TU Delft Multimedia Computing; Xi’an Jiaotong University); Qiao, T. (TU Delft Multimedia Computing; Zhejiang University); Zhu, Jihua (Xi’an Jiaotong University); Hanjalic, A. (TU Delft Intelligent Systems); Scharenborg, O.E. (TU Delft Multimedia Computing)","","2020","An estimated half of the world’s languages do not have a written form, making it impossible for these languages to benefit from any existing text-based technologies. In this paper, a speech-to-image generation (S2IG) framework is proposed which translates speech descriptions to photo-realistic images without using any text information, thus allowing unwritten languages to potentially benefit from this technology. The proposed S2IG framework, named S2IGAN, consists of a speech embedding network (SEN) and a relation-supervised densely-stacked generative model (RDG). SEN learns the speech embedding with the supervision of the corresponding visual information. Conditioned on the speech embedding produced by SEN, the proposed RDG synthesizes images that are semantically consistent with the corresponding speech descriptions. Extensive experiments on datasets CUB and Oxford-102 demonstrate the effectiveness of the proposed S2IGAN on synthesizing high-quality and semantically-consistent images from the speech signal, yielding a good performance and a solid baseline for the S2IG task.","Adversarial learning; Multimodal modelling; Speech embedding; Speech-to-image generation","en","conference paper","ISCA","","","","","","","","","Intelligent Systems","Multimedia Computing","","",""
"uuid:75b7dc3f-7fb9-444c-af37-cdd119682061","http://resolver.tudelft.nl/uuid:75b7dc3f-7fb9-444c-af37-cdd119682061","A new dynamic N2O reduction system based on Rh/ceria-zirconia: from mechanistic insight towards a practical application","Wang, Y. (TU Delft ChemE/Catalysis Engineering; Idaho National Laboratory, Idaho Falls); Posthuma De Boer, J; Makkee, M. (TU Delft ChemE/Catalysis Engineering)","","2020","Simultaneous reduction of N2O in the presence of co-existing oxidants, especially NO, from industrial plants, is a challenging task. This study explores the applications of a hydrocarbon reduced Rh/Zr stabilized La doped ceria (Rh/CLZ) catalyst in N2O abatement from oxidant rich industrial exhaust streams e.g. NO, CO2, and O2. The reaction mechanism was studied by the temporal analysis of products. The obtained results revealed that hydrocarbon pretreatment led to the creation of ceria oxygen vacancies and the formation of carbon deposits on the Rh/CLZ catalyst surface. These ceria oxygen vacancies are the active sites for the selective reduction of N2O into N2, while the dissociated O atoms from N2O fill the ceria oxygen vacancies. The oxidation of the deposited carbon via the lattice ceria oxygen generates new ceria oxygen vacancies, thereby extending the catalytic cycle. The reduction of N2O over C3H6 reduced Rh/CLZ is a process combining oxygen vacancy healing and deposited carbon oxidation. The results obtained from fixed-bed reactor experiments demonstrated that the hydrocarbon reduced Rh/CLZ catalyst provided a unique and extraordinary N2O abatement performance in the presence of co-existing competing oxidants (reactivity order: N2O ∼ NO > O2 > CO2 ∼ H2O).","","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:2a206415-c67b-4605-a40f-6775321abaf9","http://resolver.tudelft.nl/uuid:2a206415-c67b-4605-a40f-6775321abaf9","Ultrasound transmission tomography image reconstruction with a fully convolutional neural network","Zhao, Wenzhao (University of Heidelberg); Wang, Hongjian (Donghua University); Gemmeke, Hartmut (Karlsruhe Institut für Technologie); van Dongen, K.W.A. (TU Delft ImPhys/Medical Imaging); Hopp, Torsten (Karlsruhe Institut für Technologie); Hesser, Jürgen (University of Heidelberg)","","2020","Image reconstruction of ultrasound computed tomography based on the wave equation is able to show much more structural details than simpler ray-based image reconstruction methods. However, to invert the wave-based forward model is computationally demanding. To address this problem, we develop an efficient fully learned image reconstruction method based on a convolutional neural network. The image is reconstructed via one forward propagation of the network given input sensor data, which is much faster than the reconstruction using conventional iterative optimization methods. To transform the ultrasound measured data in the sensor domain into the reconstructed image in the image domain, we apply multiple down-scaling and up-scaling convolutional units to efficiently increase the number of hidden layers with a large receptive and projective field that can cover all elements in inputs and outputs, respectively. For dataset generation, a paraxial approximation forward model is used to simulate ultrasound measurement data. The neural network is trained with a dataset derived from natural images in ImageNet and tested with a dataset derived from medical images in OA-Breast Phantom dataset. Test results show the superior efficiency of the proposed neural network to other reconstruction algorithms including popular neural networks. When compared with conventional iterative optimization algorithms, our neural network can reconstruct a 110 × 86 image more than 20 times faster on a CPU and 1000 times faster on a GPU with comparable image quality and is also more robust to noise.","Breast cancer; Fully convolutional neural network; Image reconstruction; Paraxial approximation; Ultrasound transmission tomography","en","journal article","","","","","","Accepted Author Manuscript","","2021-11-25","","","ImPhys/Medical Imaging","","",""
"uuid:8a9680a8-bd8e-471a-b07f-788e1f097ad6","http://resolver.tudelft.nl/uuid:8a9680a8-bd8e-471a-b07f-788e1f097ad6","A Network-Based Model of Passenger Transfer Flow between Bus and Metro: An Application to the Public Transport System of Beijing","Wang, Wenjing (Beijing University of Technology; Ministry of Transport of the People's Republic of China); Wang, Y. (TU Delft Transport and Planning); Correia, Gonçalo (TU Delft Transport and Planning); Chen, Y. (TU Delft Transport and Planning)","","2020","In a multimodal public transport network, transfers are inevitable. Planning and managing an efficient transfer connection is thus important and requires an understanding of the factors that influence those transfers. Existing studies on predicting passenger transfer flows have mainly used transit assignment models based on route choice, which need extensive computation and underlying behavioral assumptions. Inspired by studies that use network properties to estimate public transport (PT) demand, this paper proposes to use the network properties of a multimodal PT system to explain transfer flows. A statistical model is estimated to identify the relationship between transfer flow and the network properties in a joint bus and metro network. Apart from transfer time, the number of stops, and bus lines, the most important network property we propose in this study is transfer accessibility. Transfer accessibility is a newly defined indicator for the geographic factors contributing to the possibility of transferring at a station, given its position in a multimodal PT network, based on an adapted gravity-based measure. It assumes that transfer accessibility at each station is proportional to the number of reachable points of interest within the network and dependent on a cost function describing the effect of distance. The R-squared of the regression model we propose is 0.69, based on the smart card data, PT network data, and Points of Interest (POIs) data from the city of Beijing, China. This suggests that the model could offer some decision support for PT planners especially when complex network assignment models are too computationally intensive to calibrate and use.","","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:e674fff6-6bbf-4318-a6e3-1da508bb4df4","http://resolver.tudelft.nl/uuid:e674fff6-6bbf-4318-a6e3-1da508bb4df4","Integration of Active Morphing Technology With Smart Morphing Wing Concept for Simultaneous In-Flight Performance Optimisation, Load Alleviation and Flight Dynamic Control (PPT)","Mkhoyan, T. (TU Delft Arts & Crafts; TU Delft Aerospace Structures & Computational Mechanics); Stuber, V.L. (TU Delft Novel Aerospace Materials); Nazeer, N. (TU Delft Structural Integrity & Composites); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics); Groves, R.M. (TU Delft Structural Integrity & Composites); Groen, W.A. (TU Delft Aerospace Structures & Materials); van der Zwaag, S. (TU Delft Novel Aerospace Materials); Sodja, J. (TU Delft Aerospace Structures & Computational Mechanics); Wang, X. (TU Delft ChemE/Catalysis Engineering)","","2020","PowerPoint presentation","","en","other","","","","","","","","","","Aerospace Structures & Materials","Arts & Crafts","","",""
"uuid:fe5749fe-a392-45a9-aa97-564f6df20564","http://resolver.tudelft.nl/uuid:fe5749fe-a392-45a9-aa97-564f6df20564","Dynamic rolling horizon scheduling of waterborne AGVs for inter terminal transport","Zheng, Huarong (Zhejiang University); Jin, Chen (Beihang University); Luo, Xiling (Beihang University); Negenborn, R.R. (TU Delft Transport Engineering and Logistics); Wang, Yuexuan (Zhejiang University)","","2020","The demand for transport between terminals within port areas, known as inter terminal transport (ITT), is increasing. This paper proposes a dynamic rolling horizon scheduling strategy for ITT using waterborne Autonomous Guided Vessels (waterborne AGVs). The strategy is dynamic in that it can handle the dynamically arriving ITT requests and adapt transport schedules accordingly in real time. Specifically, every certain period of time, we formulate and solve a pick-up and delivery problem considering the dynamic vessel states, waterway network topology, and ITT requests over a future time horizon. In the dynamic setting, waterborne AGVs are allowed to divert from the previously scheduled destination. Moreover, the distances between terminals are not calculated simply as the Euclidean metric but based on the complex port waterway network, which complicates the dynamic problem even more. Time windows of ITT requests, capacity constraints of waterborne AGVs and load/unload service times at terminals are also taken into account. A waterborne ITT transport network in the Port of Rotterdam is constructed. Simulation results demonstrate the effectiveness of the proposed dynamic scheduling strategy.","Vehicle dynamics; Dynamic scheduling; Containers; Routing; Real-time systems; Euclidean distance; Task analysis","en","conference paper","IEEE","","","","","Accepted Author Manuscript","","","","","Transport Engineering and Logistics","","",""
"uuid:6e70e11e-d76e-4589-bb6b-0708137893ab","http://resolver.tudelft.nl/uuid:6e70e11e-d76e-4589-bb6b-0708137893ab","Exploiting Blockage in VLC Networks Through User Rotations","Beysens, Jona (Katholieke Universiteit Leuven); Wang, Q. (TU Delft Embedded Systems); Pollin, Sofie (Katholieke Universiteit Leuven)","","2020","Visible Light Communication (VLC) has attracted significant attention over the past decade. Although numerous research studies have been performed to improve the data rate of VLC links, an important fact has been largely neglected: human bodies that host VLC receivers could block their Line-of-Sight (LOS) downlinks, and thus, degrade the system performance greatly. In this paper, we propose a system that can significantly improve the robustness for VLC networks by avoiding performance degradation due to blockage. A novel user-in-the-loop mechanism is designed in which users (including human bodies and VLC receivers) are guided by the network to rotate themselves to improve the system performance and the individual user experience. Both our simulation and experimental results demonstrate that the proposed user-in-the-loop mechanism can improve the system throughput and user fairness on average by 48% and 14%, respectively. For individual users, the average gain in throughput can reach up to 135%. Furthermore, to make the system more practical, two lightweight heuristics are designed and implemented which can achieve similar gains while reducing the computational complexity by 99%.","Blockage; robust; user rotation; user-in-the-loop; visible light communication.","en","journal article","","","","","","","","","","","Embedded Systems","","",""
"uuid:0c762b6d-7dbc-4946-879c-3c59537d772b","http://resolver.tudelft.nl/uuid:0c762b6d-7dbc-4946-879c-3c59537d772b","Poster: Securing IoT through Coverage-Bounding Wireless Communication with Visible Light","Wang, Q. (TU Delft Embedded Systems); Beysens, Jona (Katholieke Universiteit Leuven); Singelee, Dave (Katholieke Universiteit Leuven); Pollin, Sofie (Katholieke Universiteit Leuven)","Guérin, Roch (editor); Steenkiste, Peter (editor)","2020","We propose a concept of coverage-bounding and 'visual' wireless communication-HODOR 1-to secure the Internet of Things (IoT). Coverage-bounding means the communication coverage is controlled accurately in 3-dimensions. 'Visual' implies that the communication coverage and process are visible to user, representing an important and user-friendly side-channel for se-curing IoT. HODOR can provide secure wireless communication both psychologically (visible to users) and technically (nodes only communicate with each other within their delimited coverage). It can benefit IoT applications for secure wireless communications, especially those that demand secure interactions in proximity.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-05-21","","","Embedded Systems","","",""
"uuid:2c36f3b7-baf5-4983-86d2-a20e8b11de9a","http://resolver.tudelft.nl/uuid:2c36f3b7-baf5-4983-86d2-a20e8b11de9a","Adversarial Reconstruction Based on Tighter Oriented Localization for Catenary Insulator Defect Detection in High-Speed Railways","Wang, H. (TU Delft Railway Engineering); Nunez, Alfredo (TU Delft Railway Engineering)","","2020","The catenary insulator maintains electrical insulation between catenary and ground. Its defects may happen due to the long-term impact from vehicle and environment. At present, the research of defect detection for catenary insulator faces several challenges. 1) Localization accuracy is low, which causes the localized object to be incomplete or/and merge with unnecessary background. 2) Horizontal localization brings inevitable unnecessary information because horizontal box cannot fit well with the shape of insulator. 3) Supervised learning models for defects recognition are unreliable as the available defect samples are insufficient to train models well. To address these issues, this article proposes a novel two-stage defect detection method. In the localization stage, a novel localization network called TOL-Framework is constructed to reduce the background and realize tighter oriented localization. Compared with general basic framework Faster R-CNN, the TOL-Framework cascades a regression module inside basic framework and adds an external postprocess network, which is adversarially trained by standard insulators to refine the localization. These two novel steps greatly improve the oriented localization accuracy. In the defect detection stage, an adversarial reconstruction model that is trained only using normal samples is proposed to evaluate the defect states. A comparison with other methods is conducted using a dataset collected from a 60km section of the Changsha-Zhuzhou railway line in China. The results show the proposed method has the highest localization accuracy, and is effective for insulator defect detection.","Catenary insulator; tighter oriented localization; generative adversarial network; defect detection; deep learning; high-speed railways","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-03-10","","","Railway Engineering","","",""
"uuid:27e99d23-065c-44d4-816f-6231af80373f","http://resolver.tudelft.nl/uuid:27e99d23-065c-44d4-816f-6231af80373f","Unraveling the Hierarchy of Public Transport Networks","Wang, Z. (TU Delft Transport and Planning); Luo, D. (TU Delft Transport and Planning); Cats, O. (TU Delft Transport and Planning); Verma, T. (TU Delft Policy Analysis)","","2020","Hierarchy is regarded as a natural phenomenon of public transport networks (PTN). The imbalanced distribution of passenger flow result in a hierarchical structure of PTN and it is also related to the development of technology and the introduction of new modes. However, there is still a lack of knowledge on how to identify the hierarchical structure of the multi-layer PTN. This study proposes a three-step passenger transfer flow based methodology for separating and ranking the PTN: (1) using passenger journey data to derive transfer flow matrix; (2) applying network representation with Louvain method of community detection to separate the PTN layers; (3) performing ranking method, separating inner-transfer and inter-transfer flow. To demonstrate our method, we use one-month smart card data of The Hague, the Netherlands provided by the PTN operator HTM. Our results show that our method is able to, regardless of the geographic location and the mode of transportation, identify the hierarchy of PTN based on the passenger transfer flow pattern. Temporal attributes are also discussed to illustrate how hierarchy is time-dependent, e.g. with respect to the day of the week and the time of the day. Our method supports public transport (PT) operators during design and optimization of PTN and in determining which sets of higher-level service to prioritize during different time periods.","public transport network; hierarchy; community detection; data-driven","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-06-24","","","Transport and Planning","","",""
"uuid:88ef2786-b058-414e-80d8-d869b34918b9","http://resolver.tudelft.nl/uuid:88ef2786-b058-414e-80d8-d869b34918b9","Optimization of Traffic Efficiency at On-ramps with Connected Automated Vehicles","Chen, N. (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning)","","2020","This paper aims to optimize on-ramp merging processes for connected automated vehicles by utilizing an existing hierarchical control architecture including a decision-maker and an operational controller. The decision-maker employs surrogate linear models to predict future vehicular acceleration analytically and computes a merging sequence to minimize merging times of on-ramp vehicles. The operational controller is formulated as a model predictive control problem, which utilizes a second-order vehicle dynamics model, and regulates vehicles' accelerations and time instants to execute lateral movements of on-ramp vehicles for the merging processes respectively. Constraints on vehicular acceleration, speed, and inter-vehicle distance are considered by the decision-maker and the operational controller for practical usage. The proposed method to minimize the merging times of on-ramp vehicles and a first-in-first-out method are tested under different initial settings, including initial vehicular speeds, distributions of vehicular positions, and desired time gaps. The simulation results show that the proposed method is superior to the first-in-first-out method widely used in literature in improving merging traffic efficiency. We find that cooperation among vehicles makes the on-ramp vehicles join mainline traffic faster, and the acceptable time gap for merging affect choices of optimal merging sequences.","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-05-05","","","Transport and Planning","","",""
"uuid:e39f2bd0-b739-4c2d-8d6e-9f4c1d5d01d1","http://resolver.tudelft.nl/uuid:e39f2bd0-b739-4c2d-8d6e-9f4c1d5d01d1","Sao Paulo Cycling Network Development Design: A Minimum Spanning Tree Approach","Wang, Z. (TU Delft Transport and Planning)","Wei, Heng (editor); Wang, Haizhong (editor); Zhang, Lei (editor); An, Yisheng (editor); Zhao, Xiangmo (editor)","2020","Cycling is a heated topic in social media and a political hotspot in São Paulo. The implementation of bicycles took place in the city after the cooperation agreement signed by the Municipal Bureau of International and the Institute for Transportation and development policy in 2009. The recent 10-year development of the cycling infrastructure resulted in an unconnected and scattered network throughout the city. To improve the accessibility and increase the service coverage, the study proposed the minimum spanning tree to design a well-connected cycling network. A case study of 4 center districts has been researched. The new plan aims to serve 94.49% inhabitants within 350 m of the walking distance and create links to the daily trip destinations in the regions, such as public transport stations, schools, shopping malls, hospitals, etc.","","en","conference paper","American Society of Civil Engineers (ASCE)","","","","","Accepted Author Manuscript","","","","","Transport and Planning","","",""
"uuid:552ddb83-fa0d-4d9f-943f-b50c4b27b027","http://resolver.tudelft.nl/uuid:552ddb83-fa0d-4d9f-943f-b50c4b27b027","Model+Learning-based Optimal Control: An Inverted Pendulum Study","Baldi, S. (TU Delft Team Bart De Schutter; Southeast University); Rosa, Muhammad Ridho (Student TU Delft; Telkom University, Bandung); Wang, Yuzhang (Southeast University; Student TU Delft)","","2020","This work extends and compares some recent model+learning-based methodologies for optimal control with input saturation. We focus on two methodologies: a model-based actor-critic (MBAC) strategy, and a nonlinear policy iteration strategy. To evaluate the performance of the algorithms, these strategies are applied to the swinging up an inverted pendulum. Numerical simulations show that the neural network approximation in the MBAC strategy can be poor, and the algorithm may converge far from the optimum. In the MBAC approach neither stabilization nor monotonic convergence can be guaranteed, and it is observed that the best value function is not always corresponding to the last one. On the other side the nonlinear policy iteration approach guarantees that every new control policy is stabilizing and generally leads to a monotonically decreasing cost.","","en","conference paper","IEEE","","","","","Accepted Author Manuscript","","","","","Team Bart De Schutter","","",""
"uuid:513a5ff4-6c25-4d98-8635-6d92b078a5af","http://resolver.tudelft.nl/uuid:513a5ff4-6c25-4d98-8635-6d92b078a5af","Deep characteristics analysis on travel time of emergency traffic","Yao, Jiao (University of Shanghai for Science and Technology); Dai, Yaxuan (University of Shanghai for Science and Technology); Ni, Yiling (University of Shanghai for Science and Technology); Wang, Jin (Changsha University of Science and Technology); Zhao, J. (TU Delft Transport and Planning)","","2020","Owing to the rapid development of emergency rescue transportation in cities and the frequent emergencies, demand for emergency rescue is increasing drastically. How to select an emergency rescue route quickly and shorten the rescue travel time under the condition of limited urban road resources is of great significance. Based on the characteristics analysis of emergency rescue, this paper classifies priority levels of different emergency traffic, moreover, the travel times are also analysed with three scenarios: 1) emergency rescue vehicles encountering no queues; 2) encountered queues but lanes available; 3) encountered queues with no available lanes. Related case study shows that model in this paper can effectively shorten travel time of emergency traffic in the route and improve its efficiency.","Deep characteristics analysis; Emergency rescue traffic; Frequent emergencies; Limited urban road resources; Priority levels; Travel time","en","journal article","","","","","","Accepted Author Manuscript","","2021-05-04","","","Transport and Planning","","",""
"uuid:b682281e-2b8c-494b-858d-5b8d3738428a","http://resolver.tudelft.nl/uuid:b682281e-2b8c-494b-858d-5b8d3738428a","A method of personalized driving decision for smart car based on deep reinforcement learning","Wang, X. (TU Delft Electrical Engineering, Mathematics and Computer Science; Wuhan University of Technology); Wu, Chaozhong (Wuhan University of Technology); Xue, J. (TU Delft Safety and Security Science; Wuhan University of Technology); Chen, Z. (TU Delft Electrical Engineering, Mathematics and Computer Science; Wuhan University of Technology)","","2020","To date, automatic driving technology has become a hotspot in academia. It is necessary to provide a personalization of automatic driving decision for each passenger. The purpose of this paper is to propose a self-learning method for personalized driving decisions. First, collect and analyze driving data from different drivers to set learning goals. Then, Deep Deterministic Policy Gradient algorithm is utilized to design a driving decision system. Furthermore, personalized factors are introduced for some observed parameters to build a personalized driving decision model. Finally, compare the proposed method with classic Deep Reinforcement Learning algorithms. The results show that the performance of the personalized driving decision model is better than the classic algorithms, and it is similar to the manual driving situation. Therefore, the proposed model can effectively learn the human-like personalized driving decisions of different drivers for structured road. Based on this model, the smart car can accomplish personalized driving.","Data visualization; Deep reinforcement learning; Driving decision; Human-like; Personalization; Smart car","en","journal article","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","Safety and Security Science","","",""
"uuid:d1732d8c-f8fb-4a76-bf75-0c2e81d70c07","http://resolver.tudelft.nl/uuid:d1732d8c-f8fb-4a76-bf75-0c2e81d70c07","Flash flood early warning coupled with hydrological simulation and the rising rate of the flood stage in a mountainous small watershed in Sichuan province, China","Tu, Huawei (Wuhan University); Wang, Xiekang (Sichuan University); Zhang, Wanshun (Wuhan University); Peng, Hong (Wuhan University); Ke, Q. (TU Delft Hydraulic Structures and Flood Risk); Chen, Xiaomin (Wuhan University)","","2020","Flash floods in mountainous areas have become more severe and frequent as a result of climate change and are a threat to public safety and social development. This study explores the application of distributed hydrological models in flash floods risk management in a small watershed in Sichuan Province, China, and aims to increase early warning lead time in mountainous areas. The Hydrologic Engineering Center's Hydrologic Modeling System (HEC-HMS) model was used to simulate the flash flood process and analyze the variation in flood hydrographs. First, the HEC-HMS model was established based on geospatial data and the river network shape, and eight heavy rainfall events from 2010 to 2015 were used for model calibration and validation, showing that the HEC-HMS model was effective for the simulation of mountain floods in the study area. Second, with the assumption that rainfall and flood events have the same frequency, the flood hydrographs with different frequencies (p = 1%, 2%, 5%, and 10%) were calculated by the HEC-HMS model. The rising limbs of the flood hydrographs were significantly different and can be divided into three parts (0-5 h, 6-10 h, and 11-15 h). The rising rate of the flood stage for each part of the flood hydrograph increases in multiples. According to the analysis of the flood hydrographs, two critical early warning indicators with an invention patent were determined in the study: the flood stage for immediate evacuation and the rising rate. The application of the indicators in the study shows that it is feasible to advance the time of issuing an early warning signal, and it is expected that the indicators can offer a reference for flash flood early warning in the study area and other small watersheds in mountainous areas.","Earlywarning indicators; Flash floods; HEC-HMS model; Mountainous area; Smallwatershed","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:b8bd9657-c203-4575-a8e5-44fe3d1f7f9b","http://resolver.tudelft.nl/uuid:b8bd9657-c203-4575-a8e5-44fe3d1f7f9b","A semi-physical platform for guidance and formations of fixed-wing unmanned aerial vehicles","Yang, Jun (China State Shipbuilding Corporation); Thomas, Arun Geo (Student TU Delft); Singh, Satish (Student TU Delft); Baldi, S. (TU Delft Team Bart De Schutter; Southeast University); Wang, X. (TU Delft Team Bart De Schutter)","","2020","Unmanned Aerial Vehicles (UAVs) have multi-domain applications, fixed-wing UAVs being a widely used class. Despite the ongoing research on the topics of guidance and formation control of fixed-wing UAVs, little progress is known on implementation of semi-physical validation platforms (software-in-the-loop or hardware-in-the-loop) for such complex autonomous systems. A semi-physical simulation platform should capture not only the physical aspects of UAV dynamics, but also the cybernetics aspects such as the autopilot and the communication layers connecting the different components. Such a cyber-physical integration would allow validation of guidance and formation control algorithms in the presence of uncertainties, unmodelled dynamics, low-level control loops, communication protocols and unreliable communication: These aspects are often neglected in the design of guidance and formation control laws for fixed-wing UAVs. This paper describes the development of a semi-physical platform for multi-fixed wing UAVs where all the aforementioned points are carefully integrated. The environment adopts Raspberry Pi’s programmed in C++, which can be interfaced to standard autopilots (PX4) as a companion computer. Simulations are done in a distributed setting with a server program designed for the purpose of routing data between nodes, handling the user inputs and configurations of the UAVs. Gazebo-ROS is used as a 3D visualization tool.","Cyber-physical systems; Fixed-wing UAVs; Formation control; Guidance law; Smart sensor systems; Unmanned Aerial Vehicles (UAVs)","en","journal article","","","","","","","","","","","Team Bart De Schutter","","",""
"uuid:328a8215-0f1b-4fb8-815e-0ffa44ecaaec","http://resolver.tudelft.nl/uuid:328a8215-0f1b-4fb8-815e-0ffa44ecaaec","An efficient numerical simulator for geothermal simulation: A benchmark study","Wang, Y. (TU Delft Reservoir Engineering); Voskov, D.V. (TU Delft Reservoir Engineering; Stanford University); Khait, M. (TU Delft Reservoir Engineering); Bruhn, D.F. (TU Delft Reservoir Engineering; Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences)","","2020","Accurate prediction of temperature and pressure distribution is essential for geothermal reservoir exploitation with cold water re-injection. Depending on our knowledge about the heterogeneous structure of the subsurface, the reservoir development scheme can be optimized and the overall lifetime of the geothermal field can be extended. In this study, we present Delft Advanced Research Terra Simulator (DARTS), which provides fast and accurate energy production evaluation for geothermal applications. This simulation framework is suitable for uncertainty analysis with a large ensemble of models. In DARTS, we select the molar formulation with pressure and enthalpy as primary variables. Besides, the fully-coupled fully-implicit two-point flux approximation on unstructured grids is implemented to solve the mass and energy conservation equations. For the nonlinear solution, we employ the recently developed Operator-Based Linearization (OBL) approach. In our work, DARTS is compared with the state-of-the-art simulation frameworks using a set of benchmark tests. We demonstrate that DARTS achieves a good match for both low- and high-enthalpy conditions in comparison to other simulators. At the same time, DARTS provides high performance and flexibility of the code due to the OBL approach, which makes it particularly useful for uncertainty quantification in processes involving complex physics.","Benchmark test; Geothermal simulation; Operator-based linearization","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:46747ad7-8d45-4c86-b3f8-39ce262b4309","http://resolver.tudelft.nl/uuid:46747ad7-8d45-4c86-b3f8-39ce262b4309","The dead line for oil and gas and implication for fossil resource prediction","Pang, Xiongqi (China University of Petroleum - Beijing); Jia, Chengzao (China University of Petroleum - Beijing; Research Institute of Petroleum Exploration and Development, PetroChina, Beijing); Zhang, Kun (China University of Petroleum - Beijing; University College London (UCL)); Li, Maowen (Sinopec); Wang, Y. (TU Delft Applied Geology; China University of Petroleum - Beijing); Peng, Junwen (Bureau of Economic Geology); Li, Boyuan (China University of Petroleum - Beijing); Chen, Junqing (China University of Petroleum - Beijing)","","2020","Fossil fuel resources are invaluable to economic growth and social development. Understanding the formation and distribution of fossil fuel resources is critical for the search and exploration of them. Until now, the vertical distribution depth of fossil fuel resources has not been confirmed due to different understandings of their origins and the substantial variation in reservoir depths from basin to basin. Geological and geochemical data of 13 634 source rock samples from 1286 exploration wells in six representative petroliferous basins were examined to identify the maximum burial depth of active source rocks in each basin, which is referred to in this study as the active source rock depth limit (ASDL). Beyond the ASDL, source rocks no longer generate or expel hydrocarbons and become inactive. Therefore, the ASDL also sets the maximum depth for fossil fuel resources. The ASDLs of basins around the world are found to range from 3000 to 16 000 m, while the thermal maturities (Ro) of source rocks at the ASDLs are almost the same, with Ro ≈ 3:5±0:5 %. The Ro of 3.5% can be regarded as a general criterion to identify ASDLs. High heat flow and more oil-prone kerogen are associated with shallow ASDLs. In addition, tectonic uplift of source rocks can significantly affect ASDLs; 21.6 billion tons of reserves in six representative basins in China and 52 926 documented oil and gas reservoirs in 1186 basins around the world are all located above ASDLs, demonstrating the universal presence of ASDLs in petroliferous basins and their control on the vertical distribution of fossil fuel resources. The data used in this study are deposited in the repository of the PANGAEA database at: https://doi.org/10.1594/PANGAEA.900865 (Pang et al., 2019).","","en","journal article","","","","","","","","","","","Applied Geology","","",""
"uuid:5f4fee40-73b7-4211-989c-e75f9f3ec608","http://resolver.tudelft.nl/uuid:5f4fee40-73b7-4211-989c-e75f9f3ec608","Experimental characterization of storage stability of crumb rubber modified bitumen with warm-mix additives","Wang, H. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Erkens, S. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Petroleum Institute)","","2020","One of the main drawbacks of crumb rubber modified bitumen (CRMB) is the storage stability issue. The storage instability of CRMB impedes its further application. This study aims to develop a robust methodology to evaluate the storage stability of CRMB binders using both mechanical and morphological tests. The effects of rubber contents (0, 5%, 10%, 15%, 22% by weight of bitumen) and different non-foaming warm-mix additives (wax-based and chemical-based additives) on the storage stability of CRMB were investigated. Laboratory tests were also performed on the constituents of CRMB to have a deep understanding of the mechanism of storage instability. Standard tube separation tests were conducted on different binders. Both rheological tests and X-ray computed tomography (CT) scan tests were performed on the binder samples collected from different parts of the tube test. Separation indices were developed based on the difference in mechanical property and rubber content from the tube samples respectively. Results show that CRMB with a higher rubber content is more storage stable than that with a lower rubber content. The addition of warm-mix additives is detrimental to the storage stability of the studied CRMB. Rheological tests were performed on the individual constituents of CRMB (i.e., bitumen phase and rubber phase) to understand better the dynamic asymmetry potentially existing within the unstable CRMB binder. Results show that the residual bitumen becomes stiffer while the swollen rubber becomes softer after interaction because of the preferential absorption of light components of bitumen by rubber. The dynamic asymmetry existing between the bitumen phase and the rubber phase of CRMB results in storage instability. When the bitumen phase has similar dynamic properties as the rubber phase, the resulted binder system will be stable. It is possible to manipulate raw material properties and interaction conditions to achieve the desired crossover between two phases of CRMB and hence obtain a storage-stable CRMB blend.","Crumb rubber modified bitumen; Dynamic asymmetry; Frequency sweep; Multiple stress creep recovery; Storage stability; Warm mix asphalt; x-ray CT scan","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:bf211bb4-0627-4ee9-ae48-043b4392e924","http://resolver.tudelft.nl/uuid:bf211bb4-0627-4ee9-ae48-043b4392e924","Nagaoka ferromagnetism observed in a quantum dot plaquette","Dehollain Lorenzana, J.P. (TU Delft QCD/Vandersypen Lab; Kavli institute of nanoscience Delft); Mukhopadhyay, U. (TU Delft QuTech Advanced Research Centre; TU Delft QCD/Vandersypen Lab; Kavli institute of nanoscience Delft); Michal, V.P. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, Y. (Harvard University); Wunsch, B. (Harvard University); Reichl, C. (ETH Zürich); Wegscheider, W. (ETH Zürich); Rudner, M. S. (University of Copenhagen); Demler, E. (Harvard University); Vandersypen, L.M.K. (TU Delft QuTech Advanced Research Centre; TU Delft QCD/Vandersypen Lab; TU Delft QN/Vandersypen Lab; Kavli institute of nanoscience Delft)","","2020","Engineered, highly controllable quantum systems are promising simulators of emergent physics beyond the simulation capabilities of classical computers1. An important problem in many-body physics is itinerant magnetism, which originates purely from long-range interactions of free electrons and whose existence in real systems has been debated for decades2,3. Here we use a quantum simulator consisting of a four-electron-site square plaquette of quantum dots4 to demonstrate Nagaoka ferromagnetism5. This form of itinerant magnetism has been rigorously studied theoretically6–9 but has remained unattainable in experiments. We load the plaquette with three electrons and demonstrate the predicted emergence of spontaneous ferromagnetic correlations through pairwise measurements of spin. We find that the ferromagnetic ground state is remarkably robust to engineered disorder in the on-site potentials and we can induce a transition to the low-spin state by changing the plaquette topology to an open chain. This demonstration of Nagaoka ferromagnetism highlights that quantum simulators can be used to study physical phenomena that have not yet been observed in any experimental system. The work also constitutes an important step towards large-scale quantum dot simulators of correlated electron systems.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-09-02","","","QCD/Vandersypen Lab","","",""
"uuid:b40e56aa-7720-4887-9675-c5025bdde134","http://resolver.tudelft.nl/uuid:b40e56aa-7720-4887-9675-c5025bdde134","In-plane selective area InSb–Al nanowire quantum networks","op het Veld, R.L.M. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Eindhoven University of Technology; Kavli institute of nanoscience Delft); Xu, D. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Schaller, V. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, Q. (TU Delft QRD/Goswami Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); de Moor, M.W.A. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Vermeulen, K.J. (TU Delft BUS/Quantum Delft; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Bommer, J.D.S. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Kouwenhoven, Leo P. (TU Delft QN/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Microsoft Quantum Lab Delft; Kavli institute of nanoscience Delft); Zhang, H. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; Tsinghua University)","","2020","Strong spin–orbit semiconductor nanowires coupled to a superconductor are predicted to host Majorana zero modes. Exchange (braiding) operations of Majorana modes form the logical gates of a topological quantum computer and require a network of nanowires. Here, we utilize an in-plane selective area growth technique for InSb–Al semiconductor–superconductor nanowire networks. Transport channels, free from extended defects, in InSb nanowire networks are realized on insulating, but heavily mismatched InP (111)B substrates by full relaxation of the lattice mismatch at the nanowire/substrate interface and nucleation of a complete network from a single nucleation site by optimizing the surface diffusion length of the adatoms. Essential quantum transport phenomena for topological quantum computing are demonstrated in these structures including phase-coherence lengths exceeding several micrometers with Aharonov–Bohm oscillations up to five harmonics and a hard superconducting gap accompanied by 2e-periodic Coulomb oscillations with an Al-based Cooper pair island integrated in the nanowire network.","","en","journal article","","","","","","","","","","","QRD/Kouwenhoven Lab","","",""
"uuid:6b7d0615-a043-4d3c-838d-b0799e9ce481","http://resolver.tudelft.nl/uuid:6b7d0615-a043-4d3c-838d-b0799e9ce481","Small angle neutron scattering quantifies the hierarchical structure in fibrous calcium caseinate","Tian, B. (TU Delft RST/Neutron and Positron Methods in Materials); Wang, Zhaojun (Wageningen University & Research); de Campo, Liliana (Australian Nuclear Science and Technology Organisation); Gilbert, Elliot P. (Australian Nuclear Science and Technology Organisation; University of Queensland); Dalgliesh, Robert M. (Rutherford Appleton Laboratory); Velichko, E. (TU Delft RST/Neutron and Positron Methods in Materials); van der Goot, Atze Jan (Wageningen University & Research); Bouwman, W.G. (TU Delft RST/Neutron and Positron Methods in Materials)","","2020","Pronounced fibres are formed through simple shearing of a dense calcium caseinate dispersion. Both mechanical tests and scanning electron microscopy images demonstrate that the material is anisotropic. It is hypothesised that calcium caseinate aggregates, under shear, align into micro-fibres and bundle further into a hierarchical structure. Yet no direct evidence at the sub-micron length scale can support the assumption. Small angle neutron scattering (SANS) experiments were conducted on calcium caseinate samples prepared at different conditions. Analysis of the SANS data revealed that the micro-fibres have a diameter of ∼100nm and a length of ∼300nm. The addition of enzyme and air contributed to longer and thinner micro-fibres. Furthermore, the extent of fibre alignment at the micro-scale and the macroscopic anisotropy index followed the same trends with varying processing conditions. It is concluded that the material does indeed possess a hierarchical structure and the micro-fibres are responsible for the anisotropy on the macro-scale.","Anisotropic Guinier–Porod model; Calcium caseinate; Fibrous structure; Mechanical property; Small angle neutron scattering (SANS)","en","journal article","","","","","","","","","","","RST/Neutron and Positron Methods in Materials","","",""
"uuid:3f6b8355-4c2d-46f2-873e-688903ff7dbb","http://resolver.tudelft.nl/uuid:3f6b8355-4c2d-46f2-873e-688903ff7dbb","Water and Metal-Organic Frameworks: From Interaction toward Utilization","Liu, X. (TU Delft ChemE/Catalysis Engineering; Tianjin University); Wang, X. (TU Delft ChemE/Catalysis Engineering; Nanjing Tech University); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering)","","2020","The steep stepwise uptake of water vapor and easy release at low relative pressures and moderate temperatures together with high working capacities make metal-organic frameworks (MOFs) attractive, promising materials for energy efficient applications in adsorption devices for humidity control (evaporation and condensation processes) and heat reallocation (heating and cooling) by utilizing water as benign sorptive and low-grade renewable or waste heat. Emerging MOF-based process applications covered are desiccation, heat pumps/chillers, water harvesting, air conditioning, and desalination. Governing parameters of the intrinsic sorption properties and stability under humid conditions and cyclic operation are identified. Transport of mass and heat in MOF structures, at least as important, is still an underexposed topic. Essential engineering elements of operation and implementation are presented. An update on stability of MOFs in water vapor and liquid systems is provided, and a suite of 18 MOFs are identified for selective use in heat pumps and chillers, while several can be used for air conditioning, water harvesting, and desalination. Most applications with MOFs are still in an exploratory state. An outlook is given for further R&D to realize these applications, providing essential kinetic parameters, performing smart engineering in the design of systems, and conceptual process designs to benchmark them against existing technologies. A concerted effort bridging chemistry, materials science, and engineering is required. ©","","en","review","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:94910114-f97c-4a50-91e6-23174e8fe9e9","http://resolver.tudelft.nl/uuid:94910114-f97c-4a50-91e6-23174e8fe9e9","A new quantitative approach to tree attributes estimation based on LiDAR point clouds","Fan, Guangpeng (Beijing Forestry University; National Forestry and Grassland Administration); Nan, L. (TU Delft Urban Data Science); Chen, Feixiang (Beijing Forestry University; National Forestry and Grassland Administration); Dong, Yanqi (Beijing Forestry University); Wang, Zhiming (Beijing Forestry University); Li, Hao (Beijing Forestry University); Chen, Danyu (Beijing Forestry University)","","2020","Tree-level information can be estimated based on light detection and ranging (LiDAR) point clouds. We propose to develop a quantitative structural model based on terrestrial laser scanning (TLS) point clouds to automatically and accurately estimate tree attributes and to detect real trees for the first time. This model is suitable for forest research where branches are involved in the calculation. First, the Adtree method was used to approximate the geometry of the tree stem and branches by fitting a series of cylinders. Trees were represented as a broad set of cylinders. Then, the end of the stem or all branches were closed. The tree model changed from a cylinder to a closed convex hull polyhedron, which was to reconstruct a 3D model of the tree. Finally, to extract effective tree attributes from the reconstructed 3D model, a convex hull polyhedron calculation method based on the tree model was defined. This calculation method can be used to extract wood (including tree stem and branches) volume, diameter at breast height (DBH) and tree height. To verify the accuracy of tree attributes extracted from the model, the tree models of 153 Chinese scholartrees from TLS data were reconstructed and the tree volume, DBH and tree height were extracted from the model. The experimental results show that the DBH and tree height extracted based on this model are in better consistency with the reference value based on field survey data. The bias, RMSE and R2 of DBH were 0.38 cm, 1.28 cm and 0.92, respectively. The bias, RMSE and R2 of tree height were-0.76 m, 1.21 m and 0.93, respectively. The tree volume extracted from the model is in better consistency with the reference value. The bias, root mean square error (RMSE) and determination coefficient (R2) of tree volume were-0.01236 m3, 0.03498 m3 and 0.96, respectively. This study provides a new model for nondestructive estimation of tree volume, above-ground biomass (AGB) or carbon stock based on LiDAR data.","Algorithm; LiDAR; Nondestructive estimation; Quantitative structure model; Tree attributes","en","journal article","","","","","","","","","","","Urban Data Science","","",""
"uuid:fd50f309-2722-460c-abb4-891ec3122fc6","http://resolver.tudelft.nl/uuid:fd50f309-2722-460c-abb4-891ec3122fc6","Asymmetric Excitation of Surface Plasmon Polaritons via Paired Slot Antennas for Angstrom Displacement Sensing","Zang, Tianyang (University of Science and Technology of China); Zang, Haofeng (University of Science and Technology of China); Xi, Z. (TU Delft ImPhys/Optics); Du, Jing (University of Science and Technology of China); Wang, Han (University of Science and Technology of China); Lu, Yonghua (University of Science and Technology of China); Wang, Pei (University of Science and Technology of China)","","2020","Optical antennas enable efficient coupling between propagating light and bonding electromagnetic waves like surface plasmon polaritons (SPPs). Under the illumination of inhomogeneous optical fields, propagating SPPs mediated by multimode antennas could be spatially asymmetric and the asymmetry strongly depends on the position of the antennas relative to the illumination field. Here we develop such asymmetric excitation of SPPs through illuminating a pair of slot antennas with the (1,0) mode Hermite-Gaussian beam. The physical scenario of the interaction between the illumination optical field and the paired slot antennas are elaborated by full-wave electromagnetic simulations. We also carry out experiments to monitor the asymmetric SPPs propagation with a back-focal plane imaging technique. By retrieving the asymmetric intensity ratio of the SPP pattern in the back-focal plane image, lateral displacement of the antennas down to angstrom level is demonstrated.","","en","journal article","","","","","","","","","","","ImPhys/Optics","","",""
"uuid:1019521f-a86f-40e1-8a22-8d87782f758a","http://resolver.tudelft.nl/uuid:1019521f-a86f-40e1-8a22-8d87782f758a","Ecological impact of land reclamation on Jiangsu coast (China): A novel ecotope assessment for Tongzhou Bay","Muller, J.R.M. (TU Delft Coastal Engineering; Royal Boskalis Westminster); Chen, Yong ping (Hohai University); Aarninkhof, S.G.J. (TU Delft Hydraulic Engineering); Chan, Ying chi (Rijksuniversiteit Groningen; NIOZ Royal Netherlands Institute for Sea Research); Piersma, Theunis (Rijksuniversiteit Groningen; NIOZ Royal Netherlands Institute for Sea Research); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Deltares); Tao, Jian feng (Hohai University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); Gong, Zheng (Hohai University)","","2020","China's continuous and rapid economic growth has led to the reclamation of large sections of the intertidal mud coast in combination with port construction, such as that of the proposed Tongzhou Bay port on the Jiangsu coast. These reclamations threaten the local ecosystem services. An ecotope distribution map was created and a hydrodynamic numerical model of Tongzhou Bay was set up to quantify the impacts of reclamation on the ecosystem. Based on the field data and model results, several abiotic features were classified into 11 ecotopes and visualized in an ecotope map of the Tongzhou Bay ecosystem. Validation with spatial distributions of two threatened shorebird species (bar-tailed godwit and great knot) showed confirmation with the mid-range and low-range littoral zones (inundated from 40% to 100% of a tidal cycle), indicating the importance of the areas with these conditions to these populations. Overlaying the ecotope map with recent and proposed land reclamation schemes revealed a loss of ecotopes, composed of the high-range (42%), mid-range (48%), and low-range (38%) littoral habitats, corresponding to a 44%–45% loss of the most important ecotopes for bar-tailed godwit and great knot (mid-range and low-range littoral zones). These results confirm the applicability of the novel ecotope assessment approach in practice.","Ecotope; Ecotope map; Intertidal mudflats; Jiangsu coast; Mapping; Migratory shorebirds; Reclamation; Tongzhou Bay","en","journal article","","","","","","","","","","Hydraulic Engineering","Coastal Engineering","","",""
"uuid:f0e86e88-a079-4750-8bfa-79a57ceb36cb","http://resolver.tudelft.nl/uuid:f0e86e88-a079-4750-8bfa-79a57ceb36cb","Addressing Unmodeled Path-Following Dynamics via Adaptive Vector Field: A UAV Test Case","Fari, S. (TU Delft Team Bart De Schutter; Politecnico di Milano; Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Wang, X. (TU Delft Team Bart De Schutter; China State Shipbuilding Corporation); Roy, S. (TU Delft Ship Design, Production and Operations); Baldi, S. (TU Delft Team Bart De Schutter; Southeast University)","","2020","The actual performance of model-based path-following methods for unmanned aerial vehicles (UAVs) shows considerable dependence on the wind knowledge and on the fidelity of the dynamic model used for design. This study analyzes and demonstrates the performance of an adaptive vector field (VF) control law which can compensate for the lack of knowledge of the wind vector and for the presence of unmodeled course angle dynamics. Extensive simulation experiments, calibrated on a commercial fixed-wing UAV and proven to be realistic, show that the new VF method can better cope with uncertainties than its standard version. In fact, while the standard VF approach works perfectly for ideal first-order course angle dynamics (and perfect knowledge of the wind vector), its performance degrades in the presence of unknown wind or unmodeled course angle dynamics. On the other hand, the estimation mechanism of the proposed adaptive VF effectively compensates for wind uncertainty and unmodeled dynamics, sensibly reducing the path-following error as compared to the standard VF.","Adaptive vector field; fixed-wing unmanned aerial vehicles (UAV); path-following; unmodeled course angle dynamics","en","journal article","","","","","","Accepted Author Manuscript","","","","","Team Bart De Schutter","","",""
"uuid:0566c099-8662-4b65-b7b3-71ed5f485809","http://resolver.tudelft.nl/uuid:0566c099-8662-4b65-b7b3-71ed5f485809","Assimilation of middepth velocities from Argo floats in the western South China Sea","Wang, Pinqiang (National University of Defense Technology); Zhang, Weimin (National University of Defense Technology; Laboratory of Software Engineering for Complex Systems); Wang, Huizan (National University of Defense Technology); Dai, Haijin (National University of Defense Technology); Wang, X. (TU Delft Mathematical Physics; College of Meteorology and Oceanography; National University of Defense Technology)","","2020","Previous studies are mainly limited to temperature and salinity (T/S) profiling data assimilation, while data assimilation based on Argo float trajectory information has received less research focus. In this study, a new method was proposed to assimilate Argo trajectory data: The middepth (indicates the parking depth of Argo floats in this study, ~1200 m) velocities are estimated from Argo trajectories and subsequently assimilated into the Regional Ocean Model System (ROMS) using four-dimensional variational data assimilation (4DVAR) method. This method can avoid a complicated float trajectory model in direct position assimilation. The 2-month assimilation experiments in South China Sea (SCS) showed that this proposed method can effectively assimilate Argo trajectory information into the model and improve middepth velocity field by adjusting the unbalanced component in the velocity increments. The assimilation of the Argo trajectory-derived middepth velocity with other observations (satellite observations and T/S profiling data) together yielded the best performance, and the velocity fields at the float parking depth are more consistent with the Argo float trajectories. In addition, this method will not decrease the assimilation performance of other observations [i.e., sea level anomaly (SLA), sea surface temperature (SST), and T/S profiles], which is indicative of compatibility with other observations in the 4DVAR assimilation system.","","en","journal article","","","","","","","","2020-07-01","","","Mathematical Physics","","",""
"uuid:95a793f0-97a2-4c3f-973b-bf03a2333d8f","http://resolver.tudelft.nl/uuid:95a793f0-97a2-4c3f-973b-bf03a2333d8f","A high responsivity and controllable recovery ultraviolet detector based on a WO3gate AlGaN/GaN heterostructure with an integrated micro-heater","Sun, J. (TU Delft Electronic Components, Technology and Materials); Zhang, Shuo (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Zhan, Teng (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Liu, Zewen (Tsinghua University); Wang, Junxi (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Yi, Xiaoyan (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Li, Jinmin (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Sarro, Pasqualina M (TU Delft Electronic Components, Technology and Materials); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials; Shenzhen Institute of Wide-bandgap Semiconductors)","","2020","A high responsivity and controllable recovery ultraviolet (UV) photodetector based on a tungsten oxide (WO3) gate AlGaN/GaN heterostructure with an integrated micro-heater is reported for the first time. The WO3nanolayer was deposited by physical vapor deposition (PVD) for deep UV absorption and the micro-heater was integrated for chip level heating and cooling. Our device when exposed to UV wavelength exhibits a high responsivity of 1.67 × 104A W−1at 240 nm and a sharp cut-off wavelength of 275 nm. More importantly, the persistent photoconductivity (PPC) effect can be eliminated by a novel method, mono-pulse heating reset (MHR), which consists in applying an appropriate pulse voltage to the micro-heater right after the removal of the UV illumination. The recovery time was reduced from hours to just seconds without reducing the high responsivity and stability of the photodetector. The UV detection, high responsivity, high stability, controllable recovery process and low production cost of GaN-based photodetectors make these devices extremely attractive for several applications, such as fire detection and missile and rocket warning.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-07-28","","","Electronic Components, Technology and Materials","","",""
"uuid:02d2a4fe-cc14-4c3b-a414-8ed30c06fb76","http://resolver.tudelft.nl/uuid:02d2a4fe-cc14-4c3b-a414-8ed30c06fb76","Experimental Investigation of Rubber Swelling in Bitumen","Wang, H. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Apostolidis, P. (TU Delft Pavement Engineering); Erkens, S. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Khalifa University of Science and Technology)","","2020","Rubber swelling in bitumen, which is a diffusion-induced volume expansion process, plays a dominant role in the design of crumb rubber modified bitumen binders and their properties development. This study aims to investigate the kinetics of bitumen diffusion into truck tire rubber, the equilibrium swelling characteristics of rubber, and the mechanical properties of rubber before and after swelling at different high temperatures. Fourier transform infrared spectroscopy results indicate that no rubber dissolution happens during the interaction in the temperature range from 160°C to 200°C. Aliphatic compounds from bitumen preferentially diffused into rubber during the swelling process. The diffusion coefficients of bitumen into rubber were determined by the sorption test using the gravimetric method. The diffusion coefficient increases with the increase of temperature in an Arrhenius form. The volume expansion of rubber during swelling was captured by the X-ray computed tomography scan images. Rubber swells faster at the earlier stages, then the expansion rate slows down. The swelling ratio of rubber increased from 1.97 at 160°C to 3.03 at 200°C after 36 h interaction. Mechanical tests by dynamic shear rheometer reveal that swollen rubber becomes softer compared with the dry rubber and exhibits obvious viscoelastic behaviors. With the increase of temperature, the softening and viscous effect are more significant. The obtained parameters can be implemented to swelling and micromechanical models to better predict the binder properties.","","en","journal article","","","","","","Accepted Author Manuscript","","","","","Pavement Engineering","","",""
"uuid:e0a4f1dd-2798-442c-b5c1-e139b49321ac","http://resolver.tudelft.nl/uuid:e0a4f1dd-2798-442c-b5c1-e139b49321ac","Optimization of mesa etch for a quasi-vertical gan schottky barrier diode (Sbd) by inductively coupled plasma (icp) and device characteristics","Sun, Y. (TU Delft Electronic Components, Technology and Materials; Shenzhen Institute of Wide-bandgap Semiconductors; Chinese Academy of Sciences); Kang, Xuanwu (Chinese Academy of Sciences); Zheng, Yingkui (Chinese Academy of Sciences); Wei, Ke (Chinese Academy of Sciences); Li, Pengfei (Chinese Academy of Sciences); Wang, Wenbo (Shenzhen Institute of Wide-bandgap Semiconductors); Liu, Xinyu (Chinese Academy of Sciences); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2020","The optimization of mesa etch for a quasi-vertical gallium nitride (GaN) Schottky barrier diode (SBD) by inductively coupled plasma (ICP) etching was comprehensively investigated in this work, including selection of the etching mask, ICP power, radio frequency (RF) power, ratio of mixed gas, flow rate, and chamber pressure, etc. In particular, the microtrench at the bottom corner of the mesa sidewall was eliminated by a combination of ICP dry etching and tetramethylammonium hydroxide (TMAH) wet treatment. Finally, a highly anisotropic profile of the mesa sidewall was realized by using the optimized etch recipe, and a quasi-vertical GaN SBD was demonstrated, achieving a low reverse current density of 10−8 A/cm2 at −10 V.","Dry etch; GaN; Inductively coupled plasma (ICP); Mesa; Quasi-vertical; Schottky barrier diode (SBD); Sidewall profile","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:ab10927f-4e8f-4c1c-965d-1e9616dc86ec","http://resolver.tudelft.nl/uuid:ab10927f-4e8f-4c1c-965d-1e9616dc86ec","A multi-state train-following model for the analysis of virtual coupling railway operations","Quaglietta, E. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); Goverde, R.M.P. (TU Delft Transport and Planning)","","2020","The increasing need for capacity has led the railway industry to explore next generation signalling concepts such as Virtual Coupling which takes moving-block operations further by separating trains by a relative braking distance, like cars on the road. By means of a Vehicle-to-Vehicle (V2V) communication architecture trains can move in a virtually coupled platoon which can be treated as a single convoy at junctions to improve capacity. This concept however introduces the need for additional safety constraints, especially at diverging junctions, which could make actual capacity improvements insufficient to justify investments. Hence, there is a need to understand capacity performances of Virtual Coupling and potential gains over state-of-practice signalling systems. This paper addresses this need by developing an innovative train-following model that captures operational states and corresponding transitions of trains running under Virtual Coupling. A comparative capacity analysis has been conducted for a portion of the South West Main Line in the UK. Promising results have been obtained, showing that the biggest capacity gains returned by Virtual Coupling relate to operational scenarios normally found in practice with trains having service stops and using different routes.","Railway capacity; Train separation; Train-following model; Virtual coupling","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:b9065219-7841-442d-8ea0-0d3473607254","http://resolver.tudelft.nl/uuid:b9065219-7841-442d-8ea0-0d3473607254","Development of spectral-phenological features for deep learning to understand Spartina alterniflora invasion","Tian, Jinyan (Capital Normal University); Wang, Le (University at Buffalo, State University of New York); Yin, Dameng (University at Buffalo, State University of New York); Li, Xiaojuan (Capital Normal University); Diao, Chunyuan (University of Illinois at Urbana-Champaign); Gong, Huili (Capital Normal University); Shi, Chen (Capital Normal University); Menenti, M. (TU Delft Optical and Laser Remote Sensing; Chinese Academy of Sciences); Ge, Yong (Chinese Academy of Sciences)","","2020","Invasive Spartina alterniflora (S. alterniflora), a native riparian species in the U.S. Gulf of Mexico, has led to serious degradation to the ecosystem and biodiversity as well as economic losses since it was introduced to China in 1979. Although multi-temporal remote sensing offers unique capability to monitor S. alterniflora over large areas and long time periods, three major hurdle exist: (1) in the coastal zone where S. alterniflora occupies, frequent cloud coverage reduces the number of available images that can be used; (2) prominent spectral variations exist within the S. alterniflora due to phonological variations; (3) poor spectral separability between S. alterniflora and its co-dominant native species is often presented in the territories where S. alterniflora intruded in. To articulate these questions, we proposed a new pixel-based phenological feature composite method (Ppf-CM) based on Google Earth Engine. The Ppf-CM method was brainstormed to battle the aforementioned three hurdles as the basic unit for extracting phonological feature is individual pixel in lieu of an entire image scene. With the Ppf-CM-derived phenological feature as inputs, we took a step further to investigate the performance of the latest deep learning method as opposed to that of the conventional support vector machine (SVM); Lastly, we strive to understand how S. alterniflora has changed its spatial distribution in the Beibu Gulf of China from 1995 to 2017. As a result, we found (1) the developed Ppf-CM method can mitigate the phonological variation and augment the spectral separability between S. alterniflora and the background species regardless of the significant cloud coverage in the study area; (2) deep learning, compared to SVM, presented better potentials for incorporating the new phenological features generated from the Ppf-CM method; and (3) for the first time, we discovered a S. alterniflora invasion outbreak occurred during 1996–2001.","Cloudy coastal zone; Deep learning; Google earth engine; Invasive species; Phenology; Remote sensing big data","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:aac0a9e2-baed-4f1d-bb34-94d9a197ecea","http://resolver.tudelft.nl/uuid:aac0a9e2-baed-4f1d-bb34-94d9a197ecea","Comparative Study on the Early Stage of Skid Resistance Development between Polyurethane-Bound Porous Mixture and Asphalt Mixture","Shi, Jiachen (Tongji University); Cong, Lin (Tongji University); Yang, Fan (Tongji University); Wang, T. (TU Delft Urban Studies); Tan, Le (Tongji University); Yu, Meng (Beijing Oriental Yuhong Waterproof Technology Co.)","","2020","Polyurethane-bound porous mixture (PPM) is a new type of pavement material that has shown some potential for overcoming common asphalt mixtures mechanical failures. However, little research has been done on its skid resistance performance. This work presents a comparative study of the skid resistance development between PPM and asphalt mixtures at their early stage. In this study, the three mixtures were bonded by three type binders. The three type binders were polyurethane, 70# virgin bitumen, and styrene-butadiene-styrene (SBS) modified asphalt. In order to distinguished the three type mixtures, we named them PPM, BAM, and SAM respectively. A Taber abraser was used to test the polishing property of binders. A third-scale model mobile loading simulator (MMLS3) was used to simulate the traffic loadings on mixtures, and a British pendulum tester was used to measure the skid resistance of the three types of mixtures in the loading process. The binder polishing test results show a good linear relationship between the binder's mass loss and the polishing cycle. The slope of the fitting line of the two parameters was defined as binder coefficient (BC) to characterize the polishing property of the binder. The mixture test results show that the skid resistance development trend of three mixtures is similar, as it first increases, then decreases, then finally flattens. However, the British pendulum number peak value and stable value of PPM are lower than that of SAM. The order of the number of loading times of peak (NLTP) of the three mixtures is SAM>PPM>BAM. Another good linear relationship is found between BC and NLTP, and the R2 of the fitting model is 0.85, which indicates that the polishing property of binder is effective for predicting the moment of occurrence of the mixture skid resistance peak.","Model mobile load simulator equipment; Polishing property of binder; Polyurethane-bound porous mixtures; Skid resistance development","en","journal article","","","","","","Accepted Author Manuscript","","","","","Urban Studies","","",""
"uuid:e2964583-4236-47c4-b157-580d84a2710e","http://resolver.tudelft.nl/uuid:e2964583-4236-47c4-b157-580d84a2710e","Experimental and numerical investigation of damage development in embedded rail system under longitudinal force","Wang, L. (TU Delft Railway Engineering; Southwest Jiaotong University); Wang, Ping (Southwest Jiaotong University); Chen, Rong (Southwest Jiaotong University); Li, S. (TU Delft Railway Engineering); Li, Z. (TU Delft Railway Engineering)","","2020","Embedded rail system (ERS) is a new type of track structure with many advantages due to its continuous rail support. The rapid development of urban rail transit all over the world renders its application prospect broad. However, the cracks and debonds in ERS present a threat to the traffic safety and a possibility for high maintenance costs. In this work, a longitudinal pushing experiment was designed to explore the damage development process in ERS in order to help structural optimization and performance maintenance. The first order derivative of displacement-longitudinal force curve indicates that the damage process of ERS could be divided into three stages: linear elasticity, damage initiation and damage acceleration stages. The surface deformation of the elastic poured compound (EPC) was analyzed with the particle velocimetry and it is shown that the damage is possibly localized in a small EPC part. Statistics of the absolute displacements of a large number of interrogation areas show that their percentage distribution changes in agreement with the increment of rail displacement, which could be the basis for monitoring of EPC deformation in the breathing zone of continuous welded rail. The analysis of the deformation of EPC from side views, together with the qualitative analysis with finite element method, reveals that the large shear strain of rubber strip and the intense shear strain of EPC at rail foot are the main causes of damage initiation and growth in ERS under longitudinal force.","Damage development; Digital image correlation; Embedded rail system; Finite element analysis; Particle image velocity; Shear strain","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-11-16","","","Railway Engineering","","",""
"uuid:ff15478b-5805-45fe-b198-f5a5fe7be6fe","http://resolver.tudelft.nl/uuid:ff15478b-5805-45fe-b198-f5a5fe7be6fe","Experimental and analytical studies on shear behaviors of FRP-concrete composite sections","Zou, Xingxing (Missouri University of Science and Technology); Feng, Peng (Tsinghua University); Bao, Yi (Stevens Institute of Technology); Wang, Jingquan (Southeast University); Xin, H. (TU Delft Steel & Composite Structures)","","2020","The design of FRP profile-concrete composite sections, including beams and decks, is usually governed by the shear strength of the FRP profiles. However, analytical methods that can precisely predict the shear capacity of the composite sections have not been well developed, because there is lack of knowledge of the FRP-concrete composite action and distribution of shear stress along the FRP. This paper investigates the shear behaviors of FRP-concrete composite sections and develops formulae to predict the shear capacity of the composite sections. First, flexural tests of three FRP-concrete composite beams were conducted to investigate the shear failure mode and interface behaviors. All the beams failed in FRP shear fracture along horizontal direction. Then, push-out tests were used to determine the slip property for the FRP-concrete interface which reveals that FRP stay-in-place form and steel bolts can ensure full and partial composite action, respectively. Based on the experimental study, closed-form equations to compute the maximum shear stress are derived and validated against experimental data in this paper and literature. Finally, simple yet reliable equations of shear capacity are derived and recommended for engineers to design the FRP-concrete composite sections.","Composite action; FRP-concrete composite sections; Shear capacity; Shear connection; Slip effect","en","journal article","","","","","","Accepted author manuscript","","2022-05-08","","","Steel & Composite Structures","","",""
"uuid:282697ba-7bee-41a1-b4f9-79972cca891e","http://resolver.tudelft.nl/uuid:282697ba-7bee-41a1-b4f9-79972cca891e","Seismoelectric numerical simulation in 2D vertical transverse isotropic poroelastic medium","Tohti, Munirdin (Chinese Academy of Sciences); Wang, Yibo (Chinese Academy of Sciences); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics); Zheng, Yikang (Chinese Academy of Sciences); Chang, Xu (Chinese Academy of Sciences); Yao, Yi (Chinese Academy of Sciences)","","2020","Seismoelectric coupling in an electric isotropic and elastic anisotropic medium is developed using a primary–secondary formulation. The anisotropy is of vertical transverse isotropic type and concerns only the poroelastic parameters. Based on our finite difference time domain algorithm, we solve the seismoelectric response to an explosive source. The seismic wavefields are computed as the primary field. The electric field is then obtained as a secondary field by solving the Poisson equation for the electric potential. To test our numerical algorithm, we compared our seismoelectric numerical results with analytical results obtained from Pride's equation. The comparison shows that the numerical solution gives a good approximation to the analytical solution. We then simulate the seismoelectric wavefields in different models. Simulated results show that four types of seismic waves are generated in anisotropic poroelastic medium. These are the fast and slow longitudinal waves and two separable transverse waves. All of these seismic waves generate coseismic electric fields in a homogenous anisotropic poroelastic medium. The tortuosity has an effect on the propagation of the slow longitudinal wave. The snapshot of the slow longitudinal wave has an oval shape when the tortuosity is anisotropic, whereas it has a circular shape when the tortuosity is isotropic. In terms of the Thomsen parameters, the radiation anisotropy of the fast longitudinal wave is more sensitive to the value of ε, while the radiation anisotropy of the transverse wave is more sensitive to the value of δ.","Poroelastic medium; Seismoelectric coupling; Thomsen parameters; Vertical transverse isotropy","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-10-13","","","Applied Geophysics and Petrophysics","","",""
"uuid:ab6fe53c-2d8d-4dc8-a5ed-54eeb0c63953","http://resolver.tudelft.nl/uuid:ab6fe53c-2d8d-4dc8-a5ed-54eeb0c63953","Numerical investigation of the behavior of stone ballast mixed by steel slag in ballasted railway track","Jing, Guoqing (Beijing Jiaotong University); Wang, Jingru (Beijing Jiaotong University); Wang, Haoyu (TU Delft Mechanics and Physics of Structures); Siahkouhi, Mohammad (Beijing Jiaotong University)","","2020","Recently, implementing steel slag ballast has been proposed as an appropriate material to substitute stone ballast. In this regard, one of the technical concerns is the behavior of steel slag ballast in both time and frequency domains that needs to be assessed, properly. Furthermore, the combination of stone ballast and steel slag is unavoidable in steel slag ballasted tracks during track maintenance concerning the limitation of steel slag resources. Therefore, this paper suggests an optimal stone ballast-steel slag (SB-SS) combination regarding the dynamic behavior of five SB-SS combinations as 0%SS, 25%SS, 50%SS, 75%SS and 100%SS by weight of ballast using a finite element method (FEM) model of a 50-meter test track. Moreover, using elasticity modulus and Moher-coulomb parameters obtained via a series of plate load and shear strength tests for each SB-SS combination turns FEM model to be more close to the real test track results. Experimental results show that adding steel slag particles to stone ballast increases elasticity modulus and friction angle of ballast layer resulting in the improvement of mechanical behavior of railway track. Consequently, the maximum deflections and root mean square (RMS) of accelerations decrease by increasing steel slag content. Analyzing free vibration of ballast layer combinations reveals that damping ratios of 100%SS ballast layer is the maximum value as 0.25 followed by 75%SS, 50%SS, 25%SS and 0%SS combinations. Moreover, the dominant frequencies of each ballast layer combinations determine that 0%SS, 25%SS and 50%SS coincides within the track excitation frequency range made by wheel sets, while 75%SS and 100%SS are out of which. Finally, according to all results, 75%SS ballast layer is proposed as the optimal SB-SS combination.","Finite element method; Mohr-Coulomb parameters; Plain ballasted railway track; Steel slag; Sustainable design","en","journal article","","","","","","Accepted author manuscript","","2022-07-04","","","Mechanics and Physics of Structures","","",""
"uuid:58660251-e71b-4650-8ecf-5565b1f9870f","http://resolver.tudelft.nl/uuid:58660251-e71b-4650-8ecf-5565b1f9870f","A novel bi-level distributed dynamic optimization method of ship fleets energy consumption","Wang, K. (TU Delft Transport Engineering and Logistics; Dalian Maritime University); Li, Jiayuan (Dalian Maritime University); Yan, Xinping (MOST; Wuhan University of Technology); Huang, Lianzhong (Dalian Maritime University); Jiang, X. (TU Delft Transport Engineering and Logistics); Yuan, Yupeng (Wuhan University of Technology; University of Cambridge); Ma, Ranqi (Dalian Maritime University); Negenborn, R.R. (TU Delft Transport Engineering and Logistics; MOST)","","2020","The optimization of ship energy consumption is attracting a great deal of attention, as societies seek to save energy and reduce emissions. Shipping companies are more concerned with the energy consumption of a ship fleet, as opposed to that of a single ship. Because the energy consumption of a fleet is influenced by multiple factors including environmental factors, port operations and transport demands, an improvement in a single ship's energy consumption does not necessarily mean that the overall energy consumption of a fleet is good. In addition, those factors are usually varying over time, making it hard to optimize the fleet's energy consumption by methods that do not consider these time-varying factors. Therefore, a bi-level distributed dynamic optimization method based on distributed model predictive control is proposed. Moreover, an upper-level optimization model for fleet operational decision-making and a lower-level dynamic optimization model of fleet energy consumption are established. Based on these, a control algorithm for the dynamic optimization of fleet energy consumption is developed. Finally, a case study is carried out to demonstrate the effectiveness of the method. It can further reduce the energy consumption of each ship by at least 1.1% and about 6.8% for the whole fleet.","Distributed model predictive control; EEOI; Fleet energy consumption; Speed dynamic optimization","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-07-30","","","Transport Engineering and Logistics","","",""
"uuid:efdb488a-8320-413d-a892-08769ab6caea","http://resolver.tudelft.nl/uuid:efdb488a-8320-413d-a892-08769ab6caea","Parameterization and Application of Stanghellini Model for Estimating Greenhouse Cucumber Transpiration","Yan, H. (Jiangsu University; Nanjing Hydraulic Research Institute); Huang, Song (Jiangsu University); Zhang, C. (Jiangsu University); Coenders-Gerrits, Miriam (TU Delft Water Resources); Wang, Guoqing (Nanjing Hydraulic Research Institute); Zhang, Jianyun (Nanjing Hydraulic Research Institute); Zhao, Baoshan (Jiangsu University; Shenzhen Water Planning & Design Institute Co); Acquah, Samuel Joe (Jiangsu University); Wu, Haimei (Jiangsu University); Fu, Hanwen (Jiangsu University)","","2020","Accurate estimation of transpiration (Tr) is important in the development of precise irrigation scheduling and to enhance water-use efficiency in agricultural production. In this study, the air temperature (Ta) and relative humidity (RH) were measured at three different heights (0.5, 1.0, and 1.8 m above the ground near the plant canopy) parameterize aerodynamic resistance (ra) based on the heat transfer coefficient method and to estimate Tr using the Stanghellini model (SM) during two growing seasons of cucumber in a greenhouse. The canopy resistance (rc) was parameterized by an exponential relationship of stomata resistance and solar radiation, and the estimated Tr was compared to the values measured with lysimeters. After parameterization of ra and rc, the efficiency (EF) and the Root Mean Square Error (RMSE) of the estimated Tr by the SM based on micrometeorological data at a height of 0.5 m were 95% and 18 W m−2, respectively, while the corresponding values were 86% and 29 W m−2 at a height of 1.8 m for the autumn planting season. For the spring planting season, the EF and RMSE were 92% and 34 W m−2 at a height of 0.5 m, while the corresponding values were 81% and 56 W m−2 at a height of 1.8 m, respectively. This work demonstrated that when micrometeorological data within the canopy was applied alongside the data measured above the canopy, the SM led to better agreement with the lysimeter measurements.","Aerodynamic resistance; Canopy resistance; Different observation heights; Micrometeorological data; Stanghellini model; Transpiration","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:9536b6ac-3ef2-4b23-a201-43f1733b18d8","http://resolver.tudelft.nl/uuid:9536b6ac-3ef2-4b23-a201-43f1733b18d8","Surface pretreatments on CFRP and titanium for manufacturing adhesively bonded bi-material joints","Wang, W. (TU Delft Structural Integrity & Composites); Poulis, J.A. (TU Delft Adhesion Institute); Teixeira De Freitas, S. (TU Delft Structural Integrity & Composites); Zarouchas, D. (TU Delft Structural Integrity & Composites)","","2020","Adhesive bonding is a highly desirable joining technique to join composites to metals. The surfaces of both composite and metal substrates have to be carefully treated before bonding them together, in order to avoid interface failure between the adherend's surface and adhesive. This paper describes the surface pretreatments on carbon fiber reinforced plastic (CFRP) and Titanium for the manufacturing of adhesively bonded CFRP-Titanium joints. Different treatments were applied in order to roughen and activate both substrate surfaces. The quality of the surface pretreatment using different treatment methods was initially checked by contact angle measurements. Destructive tests on the bonded specimens after various surface pretreatments, including those which provided the lowest contact angle, were performed to validate the mechanical performance of the surface treatment on the bond quality. The test procedure and results on adhesively bonded CFRP-CFRP specimens and Titanium-Titanium specimens will be presented and discussed. 100% cohesive failure in both CFRP-CFRP and Titanium-Titanium joint types guarantees the high quality of the adhesively bonded joints, and proves that the respective surface pretreatments on CFRP and Titanium excludes adhesive failures in bonded CFRP-Titanium joints.","Adhesive bonding; Bonded bi-material joints; Cohesive failure; Contact angle measurement; Surface pretreatment","en","conference paper","Applied Mechanics Laboratory","","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:d6117646-bcb8-4b0d-b0c0-e72febca837d","http://resolver.tudelft.nl/uuid:d6117646-bcb8-4b0d-b0c0-e72febca837d","Evaluation of rheological behaviors and anti-aging properties of recycled asphalts using low-viscosity asphalt and polymers","Ren, S. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Wang, H. (TU Delft Pavement Engineering); Fan, Weiyu (China University of Petroleum (East China)); Erkens, S. (TU Delft Pavement Engineering)","","2020","Recycling technology is widely used in the asphalt road construction due to its environmental and economic effects. Many efforts have focused on the performance restoration of aged base asphalt by adding light oil, but the possibility of recycling the aged asphalt using low-viscosity asphalt and polymers has been few explored. Therefore, the objective of this research is to use polymer-modified low-viscosity asphalt as rejuvenator to recycle the aged asphalt. The conventional properties, rheological behaviors as well as anti-aging performance of polymer-modified recycled asphalts were evaluated by rotational viscosity (RV) tests, dynamic shear rheometer (DSR) tests and bending beam rheometer (BBR) tests. Moreover, the effects of the concentration ratio between polymer-modified low-viscosity asphalt rejuvenator and aged asphalt on the high-temperature anti-rutting, low-temperature cracking resistance, fatigue and aging resistance abilities of recycled asphalt were studied. The results show that the low-viscosity asphalt can increase viscous components and restore the workability of aged asphalt. However, the addition of low-viscosity asphalt weakens the high-temperature properties, temperature sensitivity and anti-aging performance of aged asphalt. Fortunately, the high-temperature rutting resistance, temperature sensitivity, viscoelastic properties, low-temperature cracking resistance, anti-fatigue and aging resistance performance of recycled asphalt can be enhanced remarkably by adding SBS and CR. Meanwhile, SBS-modified recycled asphalt has better fatigue and low temperature cracking resistance properties, while CR-modified recycled asphalt has the advantages on the rutting resistance, anti-aging and temperature sensitivity performance. Furthermore, SBS5-5 and CR6-4 modified recycled asphalts both have better pavement performance than others, which is superior to the requirements of polymer modified asphalt. Therefore, it is meaningful and feasible to recycle the aged base asphalt to be polymer-modified asphalt.","Aged asphalt; Crumb rubber (CR); Low-viscosity asphalt; Recycling; Styrene-butadiene-styrene (SBS)","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:5ef3f96b-3441-4955-9f27-7bd2340860dc","http://resolver.tudelft.nl/uuid:5ef3f96b-3441-4955-9f27-7bd2340860dc","Pyrophosphate Phosphor Solid Solution with High Quantum Efficiency and Thermal Stability for Efficient LED Lighting","Zhong, Yuan (Hunan Agricultural University); Xia, Mao (Hunan Agricultural University); Chen, Zhi (Hunan Agricultural University); Gao, Peixing (Hunan Agricultural University); Hintzen, H.T.J.M. (TU Delft RST/Luminescence Materials); Wong, Wai Yeung (The Hong Kong Polytechnic University); Wang, Jing (Sun Yat-sen University); Zhou, Zhi (Hunan Agricultural University)","","2020","Phosphors with high quantum efficiency and thermal stability are greatly desired for lighting industries. Based on the design strategy of solid solution, a series of deep-blue-emitting phosphors (Sr0.99-xBax)2P2O7:0.02Eu2+ (SBxPE x = 0–0.5) are developed. Upon excitation at 350 nm, the optimized SB0.3PE phosphor shows a relatively narrow full width at half maximum (FWHM = 32.7 nm) peaking at 420 nm, which matches well with the plant absorption in blue region. Moreover, this phosphor exhibits obvious enhancement of internal quantum efficiency (IQE) (from 74% to 100%) and thermal stability (from 88% to 108% of peak intensity and from 99% to 124% of integrated area intensity at 150°C) compared with the pristine one. The white LED devices using SB0.3PE as deep-blue-emitting component show good electronic properties, indicating that SB0.3PE is promising to be used in plant growth lighting, white LEDs, and other photoelectric applications. Inorganic Materials; Materials Application; Optical Materials","Inorganic Materials; Materials Application; Optical Materials","en","journal article","","","","","","","","","","","RST/Luminescence Materials","","",""
"uuid:fb92d00c-86f3-4fe7-ac39-eb5f81cce7d4","http://resolver.tudelft.nl/uuid:fb92d00c-86f3-4fe7-ac39-eb5f81cce7d4","Fatigue performance of long-term aged crumb rubber modified bitumen containing warm-mix additives","Wang, H. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); van de Ven, Martin (TU Delft Pavement Engineering); Lu, Guoyang (Rheinisch-Westfälische Technische Hochschule); Erkens, S. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Khalifa University of Science and Technology)","","2020","Recently warm mix asphalt (WMA) technologies have been introduced to rubberized asphalt mixtures to decrease the required construction temperatures and to alleviate the hazardous gas emissions. Rubberized asphalt pavements combining with WMA have the potential to improve the long-term pavement performance. This study aims to investigate the fatigue performance of crumb rubber modified bitumen (CRMB) containing warm-mix additives using different characterization methods. The effects of crumb rubber modifier (CRM) content (5%, 10%, 15% and 22% by weight of base bitumen) and warm-mix additives on the binder fatigue performance were investigated. Various laboratory tests, including frequency sweep tests, time sweep (TS) tests and linear amplitude sweep (LAS) tests, were conducted on the long-term aged binders to obtain indicators of fatigue performance. Results show that there is a good correlation between the measured fatigue life determined by TS tests using the dissipated energy concept and the predicted fatigue life determined by LAS tests using the simplified viscoelastic continuum damage (S-VECD) theory. However, the traditional Superpave fatigue parameter and the G-R parameter cannot characterize accurate enough the fatigue performance of modified binders. CRMB binders exhibit superior fatigue performance compared to the neat bitumen. The effects of warm-mix additives on the fatigue performance are different for neat bitumen compared to CRMB binder. Based on the findings in this study, rubberized asphalt mixture combining with WMA additives is expected to have a promising long-term fatigue performance.","Crumb rubber modified bitumen; Fatigue; Linear amplitude sweep; Time sweep; Warm mix asphalt","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:b01af067-7234-4d40-ab81-c091df49eda1","http://resolver.tudelft.nl/uuid:b01af067-7234-4d40-ab81-c091df49eda1","Equalization of OSDM over time-varying channels based on diagonal-block-banded matrix enhancement","Han, Jing (Northwestern Polytechnical University); Wang, Yujie (Northwestern Polytechnical University); Gong, Zehui (Northwestern Polytechnical University); Leus, G.J.T. (TU Delft Signal Processing Systems)","","2020","Orthogonal signal-division multiplexing (OSDM) has recently emerged as a promising alternative to orthogonal frequency division multiplexing (OFDM) for high-rate wireless communications. Although providing more flexibility in system design, it suffers from a special interference structure, namely inter-vector interference (IVI), when channel time variations are present. In this paper, we first derive the general OSDM signal model over time-varying channels, and then show that a time-domain window can be used to enhance the diagonal-block-banded (DBB) approximation of the channel matrix in a transformed domain. Furthermore, based on the DBB matrix enhancement, a low-complexity OSDM equalization algorithm is designed. Simulation results indicate that the proposed equalizer has significant performance advantages over that using the direct DBB approximation.","Equalization; Inter-vector interference; OSDM; Time-varying channel; Underwater acoustic communication","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-09-30","","","Signal Processing Systems","","",""
"uuid:939e2480-5181-476e-aeb3-a50536d90224","http://resolver.tudelft.nl/uuid:939e2480-5181-476e-aeb3-a50536d90224","Micromechanical modelling of complex shear modulus of crumb rubber modified bitumen","Wang, H. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Zhang, H. (TU Delft Pavement Engineering); Apostolidis, P. (TU Delft Pavement Engineering); Erkens, S. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Petroleum Institute)","","2020","Crumb rubber modified bitumen (CRMB) can be considered as a binary composite system where rubber particles are embedded in the bitumen matrix. The bitumen-rubber interaction process (mainly swelling) significantly changes the mechanical properties of both bitumen and rubber phases. This study aims to predict the complex moduli of CRMB binders with more representative constituent parameters using micromechanical models. To achieve this goal, frequency sweep tests using a dynamic shear rheometer were performed on the liquid phase of CRMB and swollen rubber samples to represent the essential properties of bitumen matrix and rubber inclusion. In addition, the numerical swelling model was developed to estimate the effective volume concentration of rubber after swelling. Results show that the liquid phases of CRMB are stiffer and more elastic than the neat bitumen while the swollen rubber is softer and more viscous than the dry rubber. The effective volume concentration of rubber can increase to 2.126 times as the blend percentage based on the finite element analysis. Using the liquid phase of CRMB binder and swollen rubber properties as the micromechanical model inputs yield more accurate predictions. The used four micromechanical models predict well at higher frequencies while underestimating the complex modulus at lower frequencies.","Complex modulus; Crumb rubber modified bitumen; Finite element model; Micromechanics; Swelling","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:1e2dc3b5-dca1-4473-9595-66ee7e7571b9","http://resolver.tudelft.nl/uuid:1e2dc3b5-dca1-4473-9595-66ee7e7571b9","Hard or soft flood adaptation? Advantages of a hybrid strategy for Shanghai","Du, Shiqiang (Shanghai Normal University; Vrije Universiteit Amsterdam); Scussolini, Paolo (Vrije Universiteit Amsterdam); Ward, Philip J. (Vrije Universiteit Amsterdam); Zhang, Min (Shanghai Normal University); Wen, Jiahong (Shanghai Normal University); Wang, Luyang (Shanghai Normal University); Koks, Elco (Vrije Universiteit Amsterdam); Diaz-Loaiza, Andres (TU Delft Hydraulic Structures and Flood Risk; Vrije Universiteit Amsterdam); Gao, Jun (Shanghai Normal University); Ke, Q. (TU Delft Hydraulic Structures and Flood Risk); Aerts, Jeroen C.J.H. (Vrije Universiteit Amsterdam)","","2020","Flood risk is expected to increase in coastal cities, particularly in Asian megacities such as Shanghai. This paper presents an integrated modeling framework to simulate changes in the flood risk in Shanghai and provide a cost-benefit analysis of multiple adaptation strategies used to reduce risk. The results show that the potential flood risk will increase dramatically as a result of sea level rise, land subsidence, and socioeconomic development. By 2100, the expected annual damage could reach 0.8% (uncertainty range: 0.4%–1.4%) of local GDP under an optimistic emission scenario (RCP4.5), compared to the current value of 0.03%. All of the adaptation strategies can effectively reduce the flood risk under the current conditions and those in 2050. In contrast to the ‘hard’ flood protection strategies (i.e., storm-surge barriers and floodwalls), the ‘soft’ strategies (i.e., building codes and nature-based measures) cannot substantially reduce the flood risk in 2100. However, the soft strategies can play a critical role in reducing the residual risk resulting from the hard strategies. A ‘hybrid’ strategy combining a storm-surge barrier, wet-proofing, and coastal wetland development outperforms both hard and soft strategies in terms of low residual risk and high benefit/cost ratio. Additionally, the hybrid strategy can also enable a larger reduction in casualties. These findings imply that managing flood risk is more than the use of single adaptation measures. The methodology developed in this paper can enlighten Shanghai and other coastal cities on an economically and socially feasible adaptation strategy in an uncertain future.","Climate change; Coastal flood; Cost-benefit analysis; Nonstationarity; Risk management","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:b33997ae-ddac-418e-8c8f-7a096a137bc7","http://resolver.tudelft.nl/uuid:b33997ae-ddac-418e-8c8f-7a096a137bc7","Effect of laboratory aging on chemistry and rheology of crumb rubber modified bitumen","Wang, H. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Apostolidis, P. (TU Delft Pavement Engineering); van de Ven, Martin (TU Delft Pavement Engineering); Erkens, S. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Khalifa University of Science and Technology)","","2020","Aging during construction and in-service substantially changes the chemical composition and physical properties of bitumen thereof influences the performance of asphalt pavements. The modification of bitumen by crumb rubber modifier (CRM) significantly increases the complexity of the aging mechanism and is expected to improve the aging resistance of bitumen. This study aims to investigate the effects of laboratory short-term and long-term aging on the chemistry and rheology of crumb rubber modified bitumen (CRMB). Neat bitumen and CRMB with four different CRM contents were studied. Fourier transform infrared spectroscopy and dynamic shear rheometer were employed to measure the change in the chemical composition and rheological properties of binders at different aging states. Bitumen hardening, which was rheologically revealed by the frequency sweep and multiple creep recovery test results, was also reflected in the growth of carbonyl and sulfoxide functional groups. In addition, the aliphaticity and aromaticity indices of binders before and after aging were also investigated. CRMB binders showed improved aging resistance compared to neat bitumen as reflected by the decreased carbonyl and sulfoxide indices as well as the lower change in rheological parameters. Higher resistance against aging was achieved when increasing the CRM content. The results also highlight the correlation between chemistry and rheology of bitumen. Among six selected mechanical parameters of binder, the non-recoverable creep compliance and percent recovery show better correlations with the combined chemical aging index (sum of carbonyl and sulfoxide indices) than the parameters derived from the linear viscoelastic region.","Aging; Chemical composition; Crumb rubber modified bitumen; Oxidation; Rheological property","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:d44c8340-335e-4759-822e-e50b38f66c1c","http://resolver.tudelft.nl/uuid:d44c8340-335e-4759-822e-e50b38f66c1c","Design and characterization of variable stiffness structural joints","Wang, Qinyu (Eindhoven University of Technology); Senatore, Gennaro (Swiss Federal Institute of Technology); Jansen, K.M.B. (TU Delft Emerging Materials); Habraken, Arjan (Eindhoven University of Technology); Teuffel, Patrick (Eindhoven University of Technology)","","2020","This paper presents design and characterization of a new type of structural joint which can vary its stiffness through actuation. Stiffness variation is employed to control the dynamic response of frame structures equipped with such joints. The joint is made of a shape memory polymer (SMP) core which is reinforced by an SMP-aramid composite skin. A controlled stiffness reduction of the joint core material, induced by resistive heating, results in a shift of the structure natural frequencies. This work comprises two main parts: 1) characterization of material thermomechanical properties and viscoelastic behavior; 2) numerical simulations of the dynamic response of a one-story planar frame equipped with two such variable stiffness joints. The experimental material model obtained through Dynamic Mechanical Analysis has been used to carry out modal and non-linear transient analysis. However, control time delays due to heating and cooling as well as fatigue are not considered in the numerical simulations. Results have shown that through joint stiffness control, the fundamental frequency shifts up to 8.72% causing a drastic reduction of the dynamic response under resonance loading. The SMP-aramid skin is effective to restrain the joint deformation in the activated state while maintaining viscoelastic damping properties.","Adaptive structures; Control; Natural frequency shift; Structural dynamics; Variable stiffness joint; Viscoelastic material","en","journal article","","","","","","","","","","","Emerging Materials","","",""
"uuid:be8b7eca-68d6-4d49-a00b-dbf18f7fe5dc","http://resolver.tudelft.nl/uuid:be8b7eca-68d6-4d49-a00b-dbf18f7fe5dc","Influence of particle size distribution on anaerobic degradation of phenol and analysis of methanogenic microbial community","Wang, Jing (Hefei University of Technology); Wu, Benteng (Hefei University of Technology); Muñoz Sierra, Julian (TU Delft Sanitary Engineering; KWR Water Research Institute); He, Chunhua (Hefei University of Technology); Hu, Zhenhu (Hefei University of Technology); Wang, Wei (Hefei University of Technology)","","2020","Sludge morphology considerably affects the mechanism underlying microbial anaerobic degradation of phenol. Here, we assessed the phenol degradation rate, specific methanogenic activity, electron transport activity, coenzyme F420 concentration, and microbial community structure of five phenol-degrading sludge of varying particle sizes (i.e., < 20, 20–50, 50–100, 100–200, and > 200 μm). The results indicated an increase in phenol degradation rate and microbial community structure that distinctly correlated with an increase in sludge particle size. Although the sludge with the smallest particle size (< 20 μm) showed the lowest phenol degradation rate (9.3 mg COD·gVSS−1 day−1), its methanogenic activity with propionic acid, butyric acid, and H2/CO2 as substrates was the best, and the concentration of coenzyme F420 was the highest. The small particle size sludge did not contain abundant syntrophic bacteria or hydrogenotrophic methanogens, but contained abundant acetoclastic methanogens. Moreover, the floc sizes of the different sludge varied in important phenol-degrading bacteria and archaea, which may dominate the synergistic mechanism. This study provides a new perspective on the role of sludge floc size on the anaerobic digestion of phenol.","Anaerobic digestion; Methanogenic activity; Microbial community structure; Particle size distribution; Phenol degradation; Phenol-degrading sludge","en","journal article","","","","","","Accepted author manuscript","","2021-01-14","","","Sanitary Engineering","","",""
"uuid:876a71c4-d51e-46a3-aec7-fd84958a90f5","http://resolver.tudelft.nl/uuid:876a71c4-d51e-46a3-aec7-fd84958a90f5","Transient Pressure Analysis for Multifractured Horizontal Well with the Use of Multilinear Flow Model in Shale Gas Reservoir","Wang, Guangdong (CNPC); Jia, Ailin (CNPC); Wei, Yunsheng (CNPC); Xiao, C. (TU Delft Mathematical Physics)","","2020","Shale gas reservoirs (SGR) have been a central supply of carbon hydrogen energy consumption and hence widely produced with the assistance of advanced hydraulic fracturing technologies. On the one hand, due to the inherent ultralow permeability and porosity, there is stress sensitivity in the reservoirs generally. On the other hand, hydraulic fractures and the stimulated reservoir volume (SRV) generated by the massive hydraulic fracturing operation have contrast properties with the original reservoirs. These two phenomena pose huge challenges in SGR transient pressure analysis. Limited works have been done to take the stress sensitivity and spatially varying permeability of the SRV zone into consideration simultaneously. This paper first idealizes the SGR to be four linear composite regions. What is more, the SRV zone is further divided into subsections on the basis of nonuniform distribution of proppant within the SRV zone which easily yields spatially varying permeability away from the main hydraulic fracture. By means of perturbation transformation and Laplace transformation, an analytical multilinear flow model (MLFM) is obtained and validated as a comparison with the previous models. The flow regimes are identified, and the sensitivity analysis of critical parameters is conducted to further understand the transient pressure behaviors. The research results provided by this work are of significance for an effective recovery of SGR resources.","","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:10a47179-6f2c-46ed-88d2-a985d772c7b3","http://resolver.tudelft.nl/uuid:10a47179-6f2c-46ed-88d2-a985d772c7b3","Data driven modeling of the reactive oxygen species stimulated by photon energy in light therapies","Dong, Jianfei (Chinese Academy of Sciences); Wang, T. (TU Delft Electronic Components, Technology and Materials; Chinese Academy of Sciences)","","2020","Light therapies can be used to treat fungal infections. A general mechanism is attributed to the generation of cytotoxic reactive oxygen species (ROS) due to light stimulation. The effectiveness of these therapies has been widely studied in the literature via conducting biological experiments, where fungi are exposed to light with various wavelengths and power. However, despite the large amount of work reporting the experimental results, few efforts have been given to build a mathematical model that describes the amount of generated ROS as a function of the photon energy and power of the stimulating light. The lack of such a model still hinders the optimization of the light doses. In this work, we propose a novel modeling method based on experimental data, so as to establish a mathematical relationship between the ROS concentration and the stimulating photon energy and light fluence (energy density). The anti-fungal experiments were performed on Candida {}albicans (C. {}albicans) using four LED light sources with different wavelengths ranging from 385nm to 450nm. Both the viability of the fungi and the ROS concentration therein were measured during the experiments. High fitting accuracy has been achieved by the model, which therefore demonstrates the effectiveness of the proposed modeling techniques.","Biomedical engineering; data driven modeling; light therapy; light-emitting diodes; parameter estimation","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:1067b75f-1dd2-4f86-b3fd-9e85fb0145f5","http://resolver.tudelft.nl/uuid:1067b75f-1dd2-4f86-b3fd-9e85fb0145f5","The ADOP and PDOP: Two Complementary Diagnostics for GNSS Positioning","Wang, Kan (Curtin University); Teunissen, P.J.G. (TU Delft Mathematical Geodesy and Positioning; Curtin University); El-Mowafy, Ahmed (Curtin University)","","2020","Ambiguity dilution of precision (ADOP) and position dilution of precision (PDOP) are two popular scalar-diagnostics used in Global Navigation Satellite System (GNSS) positioning. Where the ADOP is a predictor for carrier-phase ambiguity resolution performance, the PDOP is meant to predict the receiver-satellite geometry's capability for precise positioning. We will show, however, that although the PDOP works well for code-based positioning, one has to exercise great care in using the PDOP for real-time kinematic (RTK) positioning. We show that the ADOP and PDOP have distinct behaviors, an important consequence of which is that one can have time periods with small PDOPs, and thus seemingly good geometry for precise positioning, but at the same time large ADOPs, thus showing that successful ambiguity resolution and therefore precise positioning will not be possible. Also, the reverse situation may occur, i.e., having large PDOPs with small ADOPs. In such a situation, the large PDOPs should not automatically lead to the conclusion of poor position performance, because the large gain that ambiguity resolution brings will often still make precise positioning possible. We will analyze and explain this complementary behavior of the PDOP and ADOP and demonstrate this both analytically and empirically. For this analysis we use real Global Positioning System (GPS) single- and multifrequency signals and GPS/Quasi-Zenith Satellite System (QZSS), GPS/Navigation with Indian Constellation (NAVIC) L5 signals of two baselines located in Perth, Australia.","Ambiguity dilution of precision (ADOP); Ambiguity success-rate (ASR); Instantaneous positioning; Integer ambiguity resolution (IAR); Position dilution of precision (PDOP); Real-time kinematic (RTK)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-08-20","","","Mathematical Geodesy and Positioning","","",""
"uuid:aba4747d-49a2-4caa-90a8-b8c659cb604a","http://resolver.tudelft.nl/uuid:aba4747d-49a2-4caa-90a8-b8c659cb604a","Projecting competition between 2-methylisoborneol and natural organic matter in adsorption onto activated carbon from ozonated source waters","Wang, Q. (TU Delft Sanitary Engineering; University of Chinese Academy of Sciences; Chinese Academy of Sciences); Zietzschmann, F.E. (TU Delft Sanitary Engineering; Berliner Wasserbetriebe); Yu, Jianwei (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Hofman, Roberta (KWR Water Research Institute); An, Wei (Chinese Academy of Sciences); Yang, Min (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Rietveld, L.C. (TU Delft Sanitary Engineering)","","2020","Though the ozone-activated carbon process has been widely applied for drinking water purification, little is known about how ozone-modified natural organic matter (NOM) competes with micropollutants in activated carbon adsorption. In this study, three natural waters and one synthetic water (standard humics solution) with highly heterogeneous NOM compositions were employed to investigate the interference of ozonated NOM with the adsorption of 2-methylisoborneol (MIB). Analysis using liquid chromatography with online carbon and UV254 detection (LC-OCD-UVD) revealed that ozonation led to various disintegration patterns of macromolecules in NOM, and UV absorbance was reduced markedly for nearly all NOM fractions. Powdered activated carbon (PAC) adsorption experiments showed that increasing ozone consumption coincided with reducing NOM competition against MIB in the three natural waters, as expressed by the fitted initial concentrations of the equivalent background compound (c0,EBC). In the synthetic water, in contrast, competition increased under low/moderate specific ozone consumptions and then decreased with further elevation of ozone consumptions. Regarding the significance on affecting ozonated NOM interference, aromaticity reduction outweighed formation of low molecular weight (LMW) organics in most cases, enhancing MIB adsorption capacity. However, disintegration of the humics fraction with larger molecular weight (1,103 g/mol, as compared to 546–697 g/mol in three natural waters) into smaller, more competitive fractions caused the observed initial deteriorated MIB adsorption in synthetic water. A superior correlation between c0,EBC and the UV absorbance of LMW organics (R2 = 0.93) over concentrations of LMW organics underlined the importance of the aromatic properties in competitive adsorption projection for ozone pretreated natural waters. Furthermore, the change of relative concentration of UV absorbing compounds during ozonation could help estimate the decrease of c0,EBC, which could be a promising tool for waterworks to adjust PAC doses for MIB removal in ozonated waters.","Activated carbon; Competitive adsorption; MIB; Natural organic matter; Ozonation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-08-04","","","Sanitary Engineering","","",""
"uuid:392c969a-cf3b-4ef0-943c-8f38e8ab14d1","http://resolver.tudelft.nl/uuid:392c969a-cf3b-4ef0-943c-8f38e8ab14d1","In-vitro and in-vivo imaging of coronary artery stents with Heartbeat OCT","Cecchetti, Leonardo (Erasmus MC); Wang, Tianshi (Erasmus MC); Hoogendoorn, Ayla (Erasmus MC); Witberg, Karen T. (Erasmus MC); Ligthart, Jurgen M.R. (Erasmus MC); Daemen, Joost (Erasmus MC); van Beusekom, Heleen M.M. (Erasmus MC); Pfeiffer, Tom; van der Steen, A.F.W. (TU Delft ImPhys/Medical Imaging; Erasmus MC; Chinese Academy of Sciences)","","2020","To quantify the impact of cardiac motion on stent length measurements with Optical Coherence Tomography (OCT) and to demonstrate in vivo OCT imaging of implanted stents, without motion artefacts. The study consists of: clinical data evaluation, simulations and in vivo tests. A comparison between OCT-measured and nominal stent lengths in 101 clinically acquired pullbacks was carried out, followed by a simulation of the effect of cardiac motion on stent length measurements, experimentally and computationally. Both a commercial system and a custom OCT, capable of completing a pullback between two consecutive ventricular contractions, were employed. A 13 mm long stent was implanted in the left anterior descending branch of two atherosclerotic swine and imaged with both OCT systems. The analysis of the clinical OCT images yielded an average difference of 1.1 ± 1.6 mm, with a maximum difference of 7.8 mm and the simulations replicated the statistics observed in clinical data. Imaging with the custom OCT, yielded an RMS error of 0.14 mm at 60 BPM with the start of the acquisition synchronized to the cardiac cycle. In vivo imaging with conventional OCT yielded a deviation of 1.2 mm, relative to the length measured on ex-vivo micro-CT, while the length measured in the pullback acquired by the custom OCT differed by 0.20 mm. We demonstrated motion artefact-free OCT-imaging of implanted stents, using ECG triggering and a rapid pullback.","Drug-eluting stent; Innovation; Optical coherence tomography","en","journal article","","","","","","","","","","","ImPhys/Medical Imaging","","",""
"uuid:320176af-7f75-4848-8995-50e1f401be68","http://resolver.tudelft.nl/uuid:320176af-7f75-4848-8995-50e1f401be68","Sediment Disposals in Estuarine Channels Alter the Eco-Morphology of Intertidal Flats","de Vet, P.L.M. (TU Delft Coastal Engineering; Deltares); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Colosimo, I. (TU Delft Environmental Fluid Mechanics); Ysebaert, T. (NIOZ Royal Netherlands Institute for Sea Research; Wageningen University & Research; Universiteit Utrecht); Herman, P.M.J. (TU Delft Environmental Fluid Mechanics; Deltares); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2020","Dredging of navigation channels in estuaries affects estuarine morphology and ecosystems. In the Western Scheldt, a two-channel estuary in the Netherlands, the navigation channel is deepened and the sediment is relocated to other parts of the estuary. We analyzed the response of an intertidal flat to sediment disposals in its adjacent channel. Decades of high-frequency monitoring data from the intertidal flat show a shift from erosion toward accretion and reveal a sequence of cascading eco-morphological consequences. We document significant morphological changes not only at the disposal sites, but also at the nearby intertidal flats. Disposals influence channel bank migration, driving changes in the evolution of the intertidal flat hydrodynamics, morphology, and grain sizes. The analyzed disposals related to an expansion of the channel bank, an increase in bed level of the intertidal flat, a decrease in flow velocities on this higher elevated flat, and locally a decrease in grain sizes. These changes in turn affect intertidal flat benthic communities (increased in quantity in this case) and the evolution of the adjacent salt marsh (retreated less or even expanded in this case). The shifts in evolution may occur years after dredged disposal begins, especially in zones of the flats farther away from the disposal locations. The consequences of sediment disposals that we identify stress the urgency of managing such interventions with integrated strategies on a system scale.","ecology; estuaries; intertidal flats; morphology; sediment disposals; sediment management","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:fd61f15c-9d07-4c2a-a21e-59f0b563dab2","http://resolver.tudelft.nl/uuid:fd61f15c-9d07-4c2a-a21e-59f0b563dab2","Physically-based landslide prediction over a large region: Scaling low-resolution hydrological model results for high-resolution slope stability assessment","Wang, S. (TU Delft Water Resources; Hohai University); Zhang, Ke (Hohai University); van Beek, Ludovicus P.H. (Universiteit Utrecht); Tian, X. (TU Delft Water Resources); Bogaard, T.A. (TU Delft Water Resources)","","2020","Rainfall-triggered shallow landslides are widespread natural hazards around the world, causing many damages to human lives and property. In this study, we focused on predicting landslides in a large region by coupling a 1 km-resolution hydrological model and a 90 m-resolution slope stability model, where a downscaling method for soil moisture via topographic wetness index was applied. The modeled hydrological processes show generally good agreements with the observed discharges: relative biases and correlation coefficients at three validation stations are all <20% and >0.60, respectively. The derived scaling law for soil moisture allows for near-conservative downscaling of the original 1-km soil moisture to 90-m resolution for slope stability assessment. For landslide prediction, the global accuracy and true positive rate are 97.2% and 66.9%, respectively. This study provides an effective and computationally efficient coupling method to predict landslides over large regions in which fine-scale topographical information is incorporated.","Hydrological model; Infinite slope model; Landslide prediction; Scaling","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-06-18","","","Water Resources","","",""
"uuid:9c31e4c9-5193-4b65-84ef-af24d79a6740","http://resolver.tudelft.nl/uuid:9c31e4c9-5193-4b65-84ef-af24d79a6740","Accelerated healing in asphalt concrete via laboratory microwave heating","Wang, H. (TU Delft Pavement Engineering); Yang, Jun (Southeast University); Lu, Guoyang (Rheinisch-Westfälische Technische Hochschule); Liu, X. (TU Delft Pavement Engineering)","","2020","Self-healing of asphalt concrete (AC) is highly dependent on temperature, and its healing capacity increases with elevated temperatures. The main objective of this study is to investigate the effect of microwave heating on promotion of self-healing in AC. With this purpose, two types of AC specimens (neat AC without additives and conductive AC containing steel fiber and graphite) were prepared to for use in thermal conductivity, microwave heating speed tests, four-point bending fatigue, and healing tests. In addition, oscillatory frequency sweep tests were carried out to obtain the flow behavior of asphalt binder. Results indicated that AC containing electrically conductive additives had a higher thermal conductivity and microwave heating speed than neat AC. It was also found that the fatigue resistance and healing capacity of conductive AC after microwave heating were higher than that of neat AC. Moreover, there exists a critical temperature (corresponding to near-Newtonian behavior temperature of asphalt binder) above which healing of AC starts and an optimum heating time (temperature) to maximize the healing effect. Finally, it was found that an intermittent heating mode with a cooling process is more effective than the consecutive heating mode to enhance the healing capacity of AC. Based on these findings, it is concluded that self-healing efficiency of AC can be enhanced via microwave heating.","Asphalt concrete; Fatigue damage; Flow behavior; Healing; Microwave heating","en","journal article","","","","","","","","2020-09-18","","","Pavement Engineering","","",""
"uuid:227dbe94-16d9-4241-8bf0-c4f5f57dd898","http://resolver.tudelft.nl/uuid:227dbe94-16d9-4241-8bf0-c4f5f57dd898","Dialysis membrane enclosed laccase catalysis combines a controlled conversion rate and recyclability without enzyme immobilization","Zhang, Jie (Chongqing University); Li, Fukun (Chongqing University); Wang, Ruiqi (Chongqing University); Tan, Xuemei (Chongqing University); Hagedoorn, P.L. (TU Delft BT/Biocatalysis)","","2020","Laccase is a versatile multicopper oxidase that holds great promise for many biotechnological applications. For such applications, it is essential to explore good biocatalytic systems for high activity and recyclability. The feasibility of membrane enclosed enzymatic catalysis (MEEC) for enzyme recycling with laccase was evaluated. The dialysis membrane enclosed laccase catalysis (DMELC) was tested for the conversion of the non-phenolic model substrate 2,2′-Azino-bis(3-ethylbenzthiazoline-6-sulfonate) (ABTS). Trametes versicolor laccase was found to be completely retained by the dialysis membrane during the process. The ABTS total conversion after DMELC reached the same values as the batch reaction of the enzyme in solution. The efficiency of DMELC conversion of ABTS under different process conditions including shaking speed, temperature, ABTS concentration and pH was investigated. The repetitive dialysis minimally affected the activity and the protein content of the enclosed laccase. DMELC retained 70.3 ± 0.8% of its initial conversion after 5 cycles. The usefulness of MEEC extends to other enzymes with the benefit of superior activity of an enzyme in solution and the recyclability which is normally only obtained with immobilized enzymes.[Figure not available: see fulltext.]","Dialysis membrane; Enzyme recycling; Laccase; Membrane enclosed enzymatic catalysis; Recyclability; OA-Fund TU Delft","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:51dc014d-5b26-4a03-8eca-a3e5f7f6485a","http://resolver.tudelft.nl/uuid:51dc014d-5b26-4a03-8eca-a3e5f7f6485a","Noise Measurements of a Low-Noise Amplifier in the FDM Readout System for SAFARI","Wang, Qian (SRON Netherlands Institute for Space Research; Rijksuniversiteit Groningen); Audley, Michael D. (SRON Netherlands Institute for Space Research); Khosropanah, Pourya (SRON Netherlands Institute for Space Research); van der Kuur, Jan (SRON Netherlands Institute for Space Research); de Lange, Gert (SRON Netherlands Institute for Space Research); Aminaei, Amin (SRON Netherlands Institute for Space Research); Boersma, Dick (SRON Netherlands Institute for Space Research); van der Tak, Floris (SRON Netherlands Institute for Space Research; Rijksuniversiteit Groningen); Gao, J.R. (TU Delft QN/Gao Lab; SRON Netherlands Institute for Space Research)","","2020","The SPICA-SAFARI instrument requires extremely sensitive transition edge sensor (TES) arrays with a noise equivalent power of 2×10-19W/Hz and a readout system with an output noise that is dominated by the detector noise. It is essential to ensure the frequency domain multiplexing (FDM) readout system in SAFARI meets the noise requirement. The FDM system in SAFARI consists essentially of LC filters, a superconducting quantum interference device, a room-temperature low-noise amplifier (LNA), and a demultiplexer. Here we present a noise study of the LNA from a laboratory amplifier chain. We found the equivalent current and voltage noise of the LNA to be 5.4pA/Hz and 315pV/Hz, respectively, which are low enough to read out SAFARI’s TES arrays.","Low-noise amplifier; Readout noise; SQUID; Transition edge sensor","en","journal article","","","","","","","","","","","QN/Gao Lab","","",""
"uuid:c88bce34-49cc-49d7-b718-5e86547c299d","http://resolver.tudelft.nl/uuid:c88bce34-49cc-49d7-b718-5e86547c299d","Human health impacts of aviation biofuel production: Exploring the application of different life cycle impact assessment (LCIA) methods for biofuel supply chains","Wang, Z. (TU Delft BT/Biotechnology and Society); Osseweijer, P. (TU Delft BT/Biotechnology and Society); Posada Duque, J.A. (TU Delft BT/Biotechnology and Society)","","2020","The life cycle human health (HH) impacts related to aviation biofuels have been understood in a limited way. Life cycle impact assessment (LCIA) methods for assessing HH are often associated with a high level of uncertainty and a low level of consensus. As a result, it remains challenging to perform a robust assessment of HH impacts with a suitable LCIA method. This study aims to systematically compare six commonly used LCIA methods for quantifying HH impacts, in order to empirically understand the potential impacts of aviation biofuel production on HH and how the results are affected by the choice of methods. Three aviation biofuel production pathways based on different feedstocks (sugarcane, eucalyptus, and macauba) were analyzed and compared to fossil aviation biofuels, on the basis of a functional unit of 1 MJ aviation fuel. The majority of the LCIA methods suggest that, in respect to midpoint impacts, macauba-based biofuel is associated with the lowest impacts and eucalyptus-based biofuel the highest; whereas at endpoint level, the results are more scattered. The LCIA methods agree that biomass conversion into aviation biofuel, H2 production, and feedstock cultivation are major contributors to life cycle HH impacts. Additionally, we provide a guideline for determining an appropriate method for assessing HH impacts.","Aviation biofuel; Human health impacts; Human toxicity; LCIA method; Life cycle assessment; Life cycle impacts assessment; Sustainability assessment","en","journal article","","","","","","","","","","","BT/Biotechnology and Society","","",""
"uuid:d9c41930-bc1d-4cc6-8008-6db717aa5817","http://resolver.tudelft.nl/uuid:d9c41930-bc1d-4cc6-8008-6db717aa5817","In-situ and numerical investigation on the dynamic response of unbounded granular material in permeable pavement","Lu, Guoyang (Rheinisch-Westfälische Technische Hochschule; The Hong Kong Polytechnic University); Wang, H. (TU Delft Pavement Engineering); Törzs, Tom (Hamburg University of Technology); Liu, Pengfei (Rheinisch-Westfälische Technische Hochschule); Zhang, Yuqing (Aston University); Wang, Dawei (Rheinisch-Westfälische Technische Hochschule; Harbin Institute of Technology); Oeser, Markus (Rheinisch-Westfälische Technische Hochschule); Grabe, Jürgen (Hamburg University of Technology)","","2020","Permeable pavements have been widely used as an effective means to improve hydrological characteristics and the ecology of the urban environment. This study aims to investigate the response of fully permeable pavement (FPP) subjected to dynamic loading under dry and saturated conditions. A full-scale test track topped with polyurethane bound permeable material (PUPM) was built to obtain the stress response with an accelerated pavement test (APT) system. In addition, comprehensive analyses were performed based on the coupled Stress-dependent Moisture-sensitive Cross-anisotropic Elastoplastic (SMAEP) model in FEM. The APT test showed that the worst state was observed when the pavement structure was fully saturated, and that and brittle failure of the pavement surface occurred when the critical load level was achieved. The prediction of vertical stress predicted by Stress-dependent Cross-anisotropic Elastic (SAE) and SMAEP were both validated with the field data. The horizontal stress predicted by SAE gave a very high and unreasonable tensile stress prediction at the bottom of the unbounded granular base (UGB) layer when subjected to the high load level. With the consideration of moisture effect and the plastic properties of the material, the prediction made by SMAEP is effective to estimate the dynamic response of the UGB layer. Based on the sensitivity analysis, the optimized designs for FPP based on PUPM were suggested.","Accelerated pavement test (APT); Finite element modeling (FEM); Pervious pavement; Polyurethane-bound pervious mixtures (PUPM); Unbounded granular base","en","journal article","","","","","","Accepted Author Manuscript","","2021-07-28","","","Pavement Engineering","","",""
"uuid:6b08638f-6d48-4ba3-873a-f307245fea6c","http://resolver.tudelft.nl/uuid:6b08638f-6d48-4ba3-873a-f307245fea6c","Effect of CaO content in raw material on the mineral composition of ferric-rich sulfoaluminate clinker","Yao, X. (TU Delft Materials and Environment; Shandong University); Yang, Shizhao (Shandong University); Dong, H. (TU Delft Materials and Environment); Wu, Shuang (Shandong University); Liang, X. (TU Delft Materials and Environment); Wang, Wenlong (Shandong University)","","2020","Ferric-rich calcium sulfoaluminate (FR-CSA) cement is an eco-friendly cement. Fe2O3 exists in different minerals of FR-CSA clinker, e.g., Ca4Al2Fe2O10 (C4AF), Ca2Fe2O5 (C2F), and Ca4Al6-2xFe2xSO16 (C4A3-xFxS-). The mineral composition depends on the chemical composition of the raw materials and significantly determines the reactivity of FR-CSA cement. To optimize the phase composition of the FR-CSA clinker, chemical reagent raw mixtures with different amounts of CaO were used to prepare the FR-CSA clinker. X-ray diffraction (XRD) analysis, Rietveld quantitative phase analysis (RQPA), Fourier Transform Infrared spectroscopy (FT-IR), and scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS) were used to identify the mineralogical conditions of the FR-CSA clinker. The results indicated that the amounts of CaO in raw materials greatly affected the iron-bearing phase formation in the FR-CSA clinker. With decreasing CaO content involved in calcination reaction, the amounts of Fe2O3 incorporated in C4A3-xFxS- increased up to 17.72 wt% (where x = 0.36). The findings make it possible to optimize the mineral composition of the FR-CSA clinker by changing the CaO content in raw materials. Furthermore, low CaO content in the raw material is beneficial to the formation of C4A3-xFxS-, which enables the use of solid wastes containing low calcium for producing FR-CSA cement.","CaO; Ferric-rich sulfoaluminate cement; Iron-bearing phase; Phase composition","en","journal article","","","","","","Accepted author manuscript","","2022-09-06","","","Materials and Environment","","",""
"uuid:6ac44401-2c02-4550-a38c-f117bd925017","http://resolver.tudelft.nl/uuid:6ac44401-2c02-4550-a38c-f117bd925017","Light scattering and rheological effects in an optical fibre coupled nanoparticle suspension","Wang, X. (TU Delft Structural Integrity & Composites); Benedictus, R. (TU Delft Structural Integrity & Composites); Groves, R.M. (TU Delft Structural Integrity & Composites)","Berghmans, Francis (editor); Mignani, Anna G. (editor)","2020","This study forms the first part of research into enhancing the forward and back scattering of light in an optical fibre using nanoparticles (NPs). This approach has the potential to enhance the sensitivity of optical fibre sensing by increasing the signal-to-noise ratio. The work described in this paper is focused on understanding the scattering of light by a suspension of NPs in refractive index matching liquid. It was noted early in the experimental work that rheological effects related to the viscosity and flow of the liquid affect the scattered light measured and therefore these effects are considered in the analysis. Gold nanoparticles in the tens to hundreds of micrometre size range were selected as the scattering particles based on their optical properties. These are suspended in a refractive index liquid with a similar refractive index to the optical fibre core. Effort was needed to transfer the NPs from their aqueous sodium citrate solution to the paraffin based solution. We investigated two types of interaction with the optical fibre: (i) dropping the NP suspension onto the end of a single-mode optical fibre and (ii) using the NP suspension as an interface between two single-mode optical fibres. It was noted that the surface tension of the liquid, the diameter of the fibre and the spacing between the fibres in case (ii) influence the reflected and transmitted light. In case of excess liquid, droplets flowed down the fibre and interestingly in case (ii) modified the reflected and forward transmitted light as it passed across the fibre interface. Our initial findings are that the influence of the gap between two optical fibres decreased after dropping refractive index liquid into the gap after fibre collimation, which is a beneficial result for understanding the influence of scattered light from a liquid containing NPs. Note, the position between the two fibres can also change due to the weight of the droplet and the fibre ends had to be re-collimated to investigate the influence of the moving droplets. These results will be expanded by additional experiments and modelling of the scattering from the nanoparticales and droplets.","Light scattering; Nanoparticle; Optical fibre; Rheological effect","en","conference paper","SPIE","","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:53a3460e-d4b0-4e30-9240-3f899d9c0bc0","http://resolver.tudelft.nl/uuid:53a3460e-d4b0-4e30-9240-3f899d9c0bc0","Unsupervised Feature Transfer for Batch Process Based on Geodesic Flow Kernel","Zhang, Zheming (Taiyuan University of Technology); Wang, Fang (Taiyuan University of Technology); Pang, Y. (TU Delft Transport Engineering and Logistics); Yan, Gaowei (Taiyuan University of Technology)","","2020","The problem of misalignment of the original measurement model is caused by nonlinear, time-varying characteristic of the batch process. In this paper, a method based on geodesic flow kernel (GFK) for feature transfer is proposed. By mapping data into the manifold space, the feature transfer from source domain to target domain is implemented. Distribution adaptation of real-time data and modeling data is performed to reduce the distribution difference between them. The historical data through distribution adaptation is used to establish a regression model to predict the real-time data, by which the unsupervised batch process soft sensor modeling is realized. The application of predicting the concentration of penicillin between different batches during the fermentation of penicillin demonstrated that the prediction accuracy of the model can be improved more effectively than the traditional soft sensor method.","Batch process; feature transfer; geodesic flow kernel; penicillin; unsupervised","en","conference paper","IEEE","","","","","Accepted Author Manuscript","","","","","Transport Engineering and Logistics","","",""
"uuid:f6899203-fc44-4147-b5e0-25b39bf2c551","http://resolver.tudelft.nl/uuid:f6899203-fc44-4147-b5e0-25b39bf2c551","Constructing dataset of classified drainage areas based on surface water-supply patterns in High Mountain Asia","Lu, Jieyu (Hunan University of Science and Technology; Chinese Academy of Sciences); Qiu, Yubao (Chinese Academy of Sciences; Finnish Meteorological Institute (FMI)); Wang, Xingxing (Chinese Academy of Sciences; Finnish Meteorological Institute (FMI)); Liang, Wenshan (Chinese Academy of Sciences); Xie, Pengfei (Chinese Academy of Sciences); Shi, Lijuan (Chinese Academy of Sciences; Finnish Meteorological Institute (FMI)); Menenti, M. (TU Delft Optical and Laser Remote Sensing; Chinese Academy of Sciences); Zhang, Dongshui (Hunan University of Science and Technology)","","2020","The High Mountain Asia (HMA) region, ranging from the Hindu Kush and Tien Shan in the west to the Himalaya in the south with an altitude between 2000 and 8844 m, holds the largest reservoir of glaciers and snow outside Earth Polar Regions. In the last decades, numerous glaciers and lake areas there have undergone tremendous changes with water redistribution. In order to increase understanding of the pattern of distribution of water resources, and their dynamic changes at the basin scale, a watershed classification based on the water replenishment patterns dataset was constructed. The input dataset are from the Randolph Glacier Inventory V.6.0 and the vector data of rivers and streams. Four datasets were thus obtained: Glacier-fed and Runoff-fed Drainage Area (GRDA), Glacier-fed and Runoff-free Drainage Area (GDA), Glacier-free and Runoff-fed Drainage Area (RDA), and the Glacier-free and Runoff-free Drainage Area (NGRDA), and the numbers of these four types of basins are 87, 107, 32, and 448 separately. The statistical results show GRDA has the largest surface area, accounting for 82.2% of the total basin area in HMA, mainly in the region of the basin with outflow rivers or streams. Dominated by small basins, the GDA area accounts for the smallest area, only 3.86% and the RDA accounts for 5.62%. For NGRDA, most are with small areas, accounting for 8.32%, and mainly distributes in the closed basin of the Qiangtang Plateau. This dataset provides a fundamental classified data source for research on water resources, climate, ecology, and environment in HMA. The published data are available at https://data.4tu.nl/download/uuid:d07d748f-d10b-4308-9626-199ef05cc9af/ and http://www.dx.doi.org/10.11922/sciencedb.923.","glacial recharge; High Mountain Asia; surface water system; water resources; watershed classification","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:4a3d26cb-b71d-4ee3-b163-7e1b1fde781b","http://resolver.tudelft.nl/uuid:4a3d26cb-b71d-4ee3-b163-7e1b1fde781b","Train trajectory optimization for improved on-time arrival under parametric uncertainty","Wang, Pengling (ETH Zürich); Trivella, Alessio (ETH Zürich); Goverde, R.M.P. (TU Delft Transport and Planning); Corman, Francesco (ETH Zürich)","","2020","In this paper we study the problem of computing train trajectories in an uncertain environment in which the values of some system parameters are difficult to determine. Specifically, we consider uncertainty in traction force and train resistance, and their impact on travel time and energy consumption. Our ultimate goal is to be able to control trains such that they will arrive on-time, i.e. within the planned running time, regardless of uncertain factors affecting their dynamic or kinematic performance. We formulate the problem as a Markov decision process and solve it using a novel numerical approach which combines: (i) an off-line approximate dynamic programming (ADP) method to learn the energy and time costs over iterations, and (ii) an on-line search process to determine energy-efficient driving strategies that respect the real-time time windows, more in general expressed as train path envelope constraints. To evaluate the performance of our approach, we conducted a numerical study using real-life railway infrastructure and train data. Compared to a set of benchmark driving strategies, the trajectories from our ADP-based method reduce the probability of delayed arrival, and at the same time are able to better use the available running time for energy saving. Our results show that accounting for uncertainty is relevant when computing train trajectories and that our ADP-based method can handle this uncertainty effectively.","Approximate dynamic programming; Parametric uncertainty; Train trajectory optimization","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:0c7e457d-4f43-4d4d-8785-0f932a1bc17e","http://resolver.tudelft.nl/uuid:0c7e457d-4f43-4d4d-8785-0f932a1bc17e","Critical review of mitigation solutions for SSO in modern transmission grids","Sewdien, V.N. (TU Delft Intelligent Electrical Power Grids; TenneT TSO B.V.); Wang, Xiongfei (Aalborg University); Rueda, José L. (TU Delft Intelligent Electrical Power Grids); van der Meijden, M.A.M.M. (TU Delft Intelligent Electrical Power Grids; TenneT TSO B.V.)","","2020","The replacement of conventional generation by power electronics-based generation changes the dynamic characteristics of the power system. This results in, among other things, the increased susceptibility to subsynchronous oscillations (SSO). First, this paper discusses three recently emerging SSO phenomena, which arise due to the interactions between (1) a doubly-fed induction generator and a series compensated transmission system; (2) a voltage source converter (VSC) and a weak grid; and (3) nearby VSCs. A fundamental review of these phenomena resulted in the requirement for a reclassification of the existing SSO phenomena. This reclassification is proposed in this work and is based on interacting components identified using participation factor analysis for the distinct phenomena. Second, a critical review of the existing mitigation measures is performed for these phenomena, highlighting the advantages and disadvantages of the solutions. The influence of the wind speed, grid strength, number of wind turbines, and several converter controller parameters are also discussed. To assist equipment manufacturers, control design engineers, and system operators in selecting and designing effective mitigation measures, the existing solutions are categorized in control solutions, hardware solutions, and solutions based on system level coordination. Finally, perspectives on open issues conclude this paper.","DFIG; FACTS; MIGRATE; Power electronic converters; Series compensation; SSCI; SSR; Stability and control","en","review","","","","","","","","","","","Intelligent Electrical Power Grids","","",""
"uuid:91e7c7d3-cf61-42f3-ad36-e362436e46e4","http://resolver.tudelft.nl/uuid:91e7c7d3-cf61-42f3-ad36-e362436e46e4","Analysis of local damages effect on mechanical responses of underwater shield tunnel via field testing and numerical simulation","Tan, Xuyan (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Chen, Weizhong (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Wang, L. (TU Delft Numerical Analysis; University of Chinese Academy of Sciences); Yang, Jianping (Chinese Academy of Sciences; University of Chinese Academy of Sciences)","","2020","The investigation of concrete structural performance is crucial to maintain the stability of infrastructure. In order to assess structural stability, this work focuses on the development of an integrated framework to detect damaged conditions in the field and analyze their effect on mechanical performance through nondestructive testing (NDT) technology and numerical models. First, a ground penetrating radar (GPR) and an infrared camera work collaboratively to identify the damaged positions of the concrete structure, with parameters calibrated by laboratory experiments. Then, a finite element model is established to study structural mechanical performance based on field conditions and detected results. In addition, the influenced regions induced by local damage are studied under different boundary conditions. As a case study, the devised method was employed in the Nanjing Yangtze River tunnel for stability assessment and disaster prevention. The detected results of the damaged conditions agree well with the actual conditions in the field. Numerical results show that the circumferential stress component is more significant than that observed longitudinally. The effect of local damage on stress implies a positive correlation with the rise of water pressure, in which the maximum stress response to the variation of water level is 45KPa per meter.","Damage; Mechanical response; Nondestructive testing; Numerical simulation; Underground structure","en","journal article","","","","","","","","","","","Numerical Analysis","","",""
"uuid:07144e7f-4d9d-466a-810c-692632f64b9e","http://resolver.tudelft.nl/uuid:07144e7f-4d9d-466a-810c-692632f64b9e","Flexural strength and rotation capacity of welded I-section steel beams with longitudinally profiled flanges","Liu, X. (Tsinghua University); Wang, Yuanqing (Tsinghua University); Ban, Huiyong (Tsinghua University); Liu, Ming (Angang Steel Company Limited, Anshan); Veljkovic, M. (TU Delft Steel & Composite Structures); Bijlaard, F.S.K. (TU Delft Steel & Composite Structures)","","2020","Application of longitudinally profiled (LP) steel plate in the flange of flexural members may provide a good solution to optimize their mechanical performance and to improve the efficiency of steel use, whilst existing design codes provide no design guidance or prediction methodology for such advanced beams in terms of flexural behaviour. To clarify their flexural strength and rotation capacity, tests on two full-scale welded I-section steel beams with longitudinally profiled flanges (LPB members) are carried out herein, as well as two traditional beams with uniform cross-section for comparison. All the specimens exhibit sufficient flexural strength and rotation capacity for seismic plastic design, and specifically, the LPB members possess even better performance in case of identical steel usage. Parametric analyses of 250 beams incorporating a wide range of flange slenderness and steel grades, are conducted by employing the validated nonlinear FE model to investigate the effects of rate of thickness change for the LP flanges. The results show that the effect is limited on the flexural strength but significant on rotation capacity. The existing design provisions for beams with uniform cross-section give generally conservative design results for the flexural strength of the LPB members, but limiting values of flange slenderness needs to be reduced. The research outcomes may provide an important basis for promoting the application of LP plates in flexural members.","Flexural strength; Longitudinally profiled steel plate; Rate of thickness change; Rotation capacity; Welded I-section steel beam","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-01-25","","","Steel & Composite Structures","","",""
"uuid:673b6d1d-be70-49f2-a313-4b7a2f9774e7","http://resolver.tudelft.nl/uuid:673b6d1d-be70-49f2-a313-4b7a2f9774e7","Photoenzymatic Production of Next Generation Biofuels from Natural Triglycerides Combining a Hydrolase and a Photodecarboxylase","Ma, Yunjian (South China University of Technology); Zhang, Xizhen (South China University of Technology); Zhang, W. (TU Delft BT/Biocatalysis); Li, Peilin (South China University of Technology); Li, Yongru (South China University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Yonghua (South China University of Technology)","","2020","A photobiocatalytic cascade transforming natural triglycerides into alkanes/alkenes is proposed. Starting from natural triglycerides, free fatty acids have been obtained using lipases. The free fatty acids were then, in a photoenzymatic step, decarboxylated into the C1-shortened alkanes using a recently described photodecarboxylase from Chlorella variabilis NC64A. This cascade produced alkanes from various natural (waste) oils in significant amounts (up to 24 g L−1) and may provide a basis for valorisation of waste oils into a next generation of biodiesel.","biocatalysis; biodiesel; cascade reactions; decarboxylation; photocatalysis","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:f4370302-31ae-4d81-8cc4-539dd70254e6","http://resolver.tudelft.nl/uuid:f4370302-31ae-4d81-8cc4-539dd70254e6","Ballast Mechanical Performance with and without Under Sleeper Pads","Guo, Y. (TU Delft Railway Engineering); Wang, Jianxi (Shijiazhuang Tiedao University); Markine, V.L. (Shijiazhuang Tiedao University); Jing, Guoqing (Beijing Jiaotong University)","","2020","With the train speed and axle load increasing, excessive stresses are produced and transmitted to the ballast layer, inducing rapid ballast degradation. To solve this issue, the under sleeper pads (USPs) have been widely applied between sleepers and ballast particles as the elastic layer. In this research, laboratory tests using half-sleeper track were carried out to study the ballast bed performance with or without the USPs under static and cyclic loading. Results show that applying the USPs reduces the track stiffness and can decrease the settlement. However, installing the USPs increases the ballast bed acceleration and the sleeper vertical acceleration. The contact areas of sleeper-ballast with USPs are over 5 times as those without USPs. The USPs assist reducing ballast degradation mainly by avoiding the ballast particle breakage at the sleeper-ballast interface and can increase the stress distribution at the longitudinal direction.","Ballast; Breakage; Cyclic loading; Settlement; USPs","en","journal article","","","","","","Accepted Author Manuscript","","2021-09-15","","","Railway Engineering","","",""
"uuid:e7db9ffc-f061-42a9-8d08-69a5c9193b02","http://resolver.tudelft.nl/uuid:e7db9ffc-f061-42a9-8d08-69a5c9193b02","Probabilistic field approach for motorway driving risk assessment","Mullakkal-Babu, F.A. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); He, X. (TU Delft Intelligent Vehicles); van Arem, B. (TU Delft Transport and Planning); Happee, R. (TU Delft Intelligent Vehicles)","","2020","We present an approach to assess the risk taken by on-road vehicles within the framework of artificial field theory, envisioned for safety analysis and design of driving support/automation applications. Here, any obstacle (neighboring entity on the road) to the subject vehicle is treated as a finite scalar risk field that is formulated in the predicted configuration space of the subject vehicle. The driving risk estimate is the strength of the risk field at the subject vehicle's future location. This risk field is formulated as the product of two factors: collision probability and expected crash energy. The collision probability with neighboring vehicles is estimated based on probabilistic motion predictions. The risk can be assessed for a single time step or over multiple future time steps, depending on the required temporal resolution of the estimates. We verified the single step approach in three near-crash situations from a naturalistic dataset and in cut-in and hard-braking scenarios with simulation and showed the application of the multi-step approach in selecting the safest path in a lane-drop section. The risk descriptions from the proposed approach qualitatively reflect the narration of the situation and are in general consistent with Time To Collision. Compared to current surrogate measures of safety, the proposed risk estimate provides a better basis to assess the driving safety of an individual vehicle by considering the uncertainty over the future ambient traffic state and magnitude of expected crash consequences. The proposed driving risk model can be used as a component of intelligent vehicle safety applications and as a comprehensive surrogate measure for assessing traffic safety.","Driver behaviour; Driving risk; Potential field; Surrogate measure of safety; Uncertainty","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:bcffaa70-1b38-4021-8298-7c5b11d598be","http://resolver.tudelft.nl/uuid:bcffaa70-1b38-4021-8298-7c5b11d598be","A novel method about the representation and discrimination of traffic state","Jiang, Junfeng (Wuhan Technology and Business University); Chen, Qiushi (Wuhan University of Technology); Xue, J. (TU Delft Safety and Security Science); Wang, Haobo (Wuhan University of Technology); Chen, Zhijun (Wuhan University of Technology)","","2020","The representation and discrimination of various traffic states play an essential role in solving traffic accidents and congestion as the foundation of traffic state prediction. However, the existing representation of the traffic state usually only considers the road congestion layer and divides the traffic state into congested and unblocked. Representation only at the congestion layer is difficult to reflect the road traffic state comprehensively. Therefore, we select three indicators from the layers of road congestion, road safety, and road stability, respectively, then utilizing K-means to cluster the traffic state. The clustering results can be regarded as a new type for the representation of a traffic state. As a result, the traffic states are divided into four classes, which comprehensively reflects the level of road congestion, safety, and stability. Using the four traffic states obtained from the clustering results as class labels, we applied a multi-layer perceptron (MLP) to classify the different traffic states, and the receiver operating characteristic (ROC) curve is assessed to verify the superiority of the classification results. Finally, a visual display of the real-time traffic state in a city’s central area was given.","K-means; Multi-layer perceptron (MLP); Road safety; Traffic accidents; Traffic congestion; Traffic flow; Traffic state","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:dbfe6d5a-b16b-4d34-ad78-6b0082e3e1a4","http://resolver.tudelft.nl/uuid:dbfe6d5a-b16b-4d34-ad78-6b0082e3e1a4","A review on the pumping behavior of modern concrete","Li, Huajian (Railway Engineering Research Institute); Sun, Deyi (Railway Engineering Research Institute); Wang, Zhen (Railway Engineering Research Institute); Huang, Fali (Railway Engineering Research Institute); Yi, Zhonglai (Railway Engineering Research Institute); Yang, Zhengxian (Fuzhou University); Zhang, Y. (TU Delft Materials and Environment; Fuzhou University)","","2020","Pumping is the most common technique used to transport fresh concrete in construction sites. The large-scale use of concrete all over the world makes the pumping increasingly important. A wide variety of additives and admixtures are incorporated into modern concrete in order for sustainable development. The performance of modern concrete is rather complex and its pumping behavior differs significantly from that of conventional concrete, especially in the fresh stage. This paper presents a comprehensive overview on the state of the art of concrete pumping. The models and methods used for characterizing the concrete pumpability and lubrication layer are described. The factors influencing the pumping behavior are discussed. A couple of ultra-high pumping engineering of concrete conducted in China are introduced.","","en","journal article","","","","","","Accepted Author Manuscript","","","","","Materials and Environment","","",""
"uuid:03e5ca34-19ee-4c38-9b44-27f9bac7faef","http://resolver.tudelft.nl/uuid:03e5ca34-19ee-4c38-9b44-27f9bac7faef","Improvements of developed graphite based composite anti-aging agent on thermal aging properties of asphalt","Hu, Zhihui (Nanjing Forestry University); Xu, Tao (Nanjing Forestry University); Liu, Pengfei (Rheinisch-Westfälische Technische Hochschule); Oeser, Markus (Rheinisch-Westfälische Technische Hochschule); Wang, H. (TU Delft Pavement Engineering)","","2020","To reduce the thermal-oxidative aging of asphalt and the release amount of harmful volatiles during the construction of asphalt pavement, a new composite anti-aging agent was developed. Since the volatiles were mainly released from saturates and aromatics during the thermal-oxidative aging of asphalt, expanded graphite (EG) was selected as a stabilizing agent to load magnesium hydroxide (MH) and calcium carbonate (CaCO3) nanoparticles for preparing the anti-aging agents of saturates and aromatics, respectively. Thermal stability and volatile constituents released from saturates and aromatics before and after the thermal-oxidative aging were characterized using the isothermal Thermogravimetry/Differential Scanning Calorimetry-Fourier Transform Infrared Spectrometer test (TG/DSC-FTIR test). Test results indicate that anti-aging agents of EG/MH and EG/CaCO3 effectively inhibit the volatilization of light components in asphalt and improve the thermal stability of saturates and aromatics. Then, the proportions of EG, MH, and CaCO3 added in the developed composite anti-aging agent of EG/MH/CaCO3 are 2:1:3 by weight. EG/MH/CaCO3 plays a synergetic effect on inhibiting the thermal-oxidative aging of asphalt, and reduces the release amount of harmful volatiles during the thermal-oxidative aging after EG/MH/CaCO3 is added into asphalt at the proposed content of 10 wt. %. EG plays a synergistic role with MH and CaCO3 nanoparticles to prevent the chain reactions, inhibiting the thermal-oxidative aging of asphalt.","Asphalt; Composite anti-aging agent; Synergistic effect; Thermal-oxidative aging; Volatile constituents","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:9a3a13dc-7fe9-4ea5-a0d7-4f956df9e44a","http://resolver.tudelft.nl/uuid:9a3a13dc-7fe9-4ea5-a0d7-4f956df9e44a","Using Complex Network Analysis for Optimization of Water Distribution Networks","Sitzenfrei, Robert (University of Innsbruck); Wang, Qi (Guangdong University of Technology); Kapelan, Z. (TU Delft Sanitary Engineering; University of Exeter); Savić, Dragan (University of Exeter; KWR Water Research Institute)","","2020","The optimization of water networks supports the decision-making process by identifying the optimal trade-off between costs and performance (e.g., resilience and leakage). A major challenge in the domain of water distribution systems (WDSs) is the network (re)design. While the complex nature of WDS has already been explored with complex network analysis (CNA), literature is still lacking a CNA of optimal water networks. Based on a systematic CNA of Pareto-optimal solutions of different WDSs, several graph characteristics are identified, and a newly developed CNA design approach for WDSs is proposed. The results show that obtained designs are comparable with results found by evolutionary optimization, but the CNA approach is applicable for large networks (e.g., 150,000 pipes) with a substantially reduced computational effort (runtime reduction up to 5 orders of magnitude).","characteristics of optimal WDSs; edge betweenness centrality; graph analysis; large networks","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:45deadb1-18cc-4e3e-97c2-b6baab2a3f46","http://resolver.tudelft.nl/uuid:45deadb1-18cc-4e3e-97c2-b6baab2a3f46","3-D Short-Range Imaging with Irregular MIMO Arrays Using NUFFT-Based Range Migration Algorithm","Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Aubry, P.J. (TU Delft Microwave Sensing, Signals & Systems); Yarovoy, Alexander (TU Delft Microwave Sensing, Signals & Systems)","","2020","3-D imaging with irregular planar multiple-input-multiple-output (MIMO) arrays is discussed. Due to signal acquisition on irregular spatial sampling grids by using these antenna arrays, the fast Fourier transform (FFT)-based imaging algorithms cannot readily be used for image formation. To avoid the application of computationally intensive coherent summation algorithms such as filtered backprojection or Kirchhoff migration, we propose a nonuniform FFT (NUFFT)-based MIMO Range Migration Algorithm (i.e., NUFFT-based MIMO-RMA) for efficient microwave imaging. The algorithm exploits NUFFT to reconstruct the wavenumber-domain spectra related to each Fourier frequency. It is generic and applicable to 3-D imaging with irregular planar MIMO arrays. The effects of irregular spatial sampling and signal bandwidth on the imaging performance and computational efficiency of the proposed algorithm are analyzed. Finally, some numerical simulations and experimental results are presented to demonstrate the performance of the proposed imaging algorithm.","3-D imaging; microwave imaging; multiple-input-multiple-output (MIMO) array; nonuniform fast Fourier transform (NUFFT); range migration","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-07-29","","","Microwave Sensing, Signals & Systems","","",""
"uuid:6fc592aa-2c65-4ee5-b9a8-ebe39ce915e1","http://resolver.tudelft.nl/uuid:6fc592aa-2c65-4ee5-b9a8-ebe39ce915e1","A Globally Conforming Lattice Structure for 2D Stress Tensor Visualization","Wang, Junpeng (Technische Universität München); Wu, J. (TU Delft Materials and Manufacturing); Westermann, Rüdiger (Technische Universität München)","","2020","We present a visualization technique for 2D stress tensor fields based on the construction of a globally conforming lattice. Conformity ensures that the lattice edges follow the principal stress directions and the aspect ratio of lattice elements represents the stress anisotropy. Since such a lattice structure cannot be space-filling in general, it is constructed from multiple intersecting lattice beams. Conformity at beam intersections is ensured via a constrained optimization problem, by computing the aspect ratio of elements at intersections so that their edges meet when continued along the principal stress lines. In combination with a coloring scheme that encodes relative stress magnitudes, a global visualization is achieved. By introducing additional constraints on the positional variation of the beam intersections, coherent visualizations are achieved when external loads or material parameters are changed. In a number of experiments using non-trivial scenarios, we demonstrate the capability of the proposed visualization technique to show the global and local structure of a given stress field.","","en","journal article","","","","","","Accepted Author Manuscript","","2021-07-18","","","Materials and Manufacturing","","",""
"uuid:c896f63e-7e40-4b62-9f89-d85634a7fc3b","http://resolver.tudelft.nl/uuid:c896f63e-7e40-4b62-9f89-d85634a7fc3b","Building for nature: Preserving threatened bird habitat in port design","Muller, J.R.M. (TU Delft Coastal Engineering; Royal Boskalis Westminster); Chan, Ying Chi (Rijksuniversiteit Groningen; Universiteit Utrecht); Piersma, Theunis (Rijksuniversiteit Groningen; Universiteit Utrecht; Global Flyway Network); Chen, Yong Ping (Hohai University); Aarninkhof, S.G.J. (TU Delft Hydraulic Engineering); Hassell, Chris J. (Global Flyway Network); Tao, Jian Feng (Hohai University); Gong, Zheng (Hohai University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Deltares)","","2020","The fast economic development of the People's Republic of China has created an increasing demand for usable land, resulting in large-scale land reclamations along the coastal zone. One of these regions is Tongzhou Bay (Jiangsu coast), a region characterized by large intertidal mudflats and deep tidal channels with potential for the development of agri-aquaculture and the construction of a deep-sea port. However, these intertidal mudflats also provide vital ecosystem services and support many wildlife species, including several endangered migratory shorebirds within the East Asian-Australasian Flyway. With increasing realization of the importance of maintaining such ecological values, a more integrated coastal development strategy is needed. This study aims to develop a sustainable integrated design for the Tongzhou Bay port, following a ""Building with Nature"" approach. We use a morphodynamic model to compute habitat suitability for two shorebird species (Great Knot Calidris tenuirostris and Bar-tailed Godwit Limosa lapponica). Several port configurations were developed on the basis of three design criteria: (1) create area for future port development, whilst (2) preserving existing high-value ecotopes for shorebirds and (3) enhance the natural accretion rate of such ecotopes. Simulation results showed a clear difference in siltation patterns, preservation and enhancement of preferred ecotopes. This work therefore demonstrates the potential and importance of morphological and habitat suitability modelling when designing large-scale reclamations and port constructions, especially in dynamic areas such as Tongzhou Bay.","Ecotope; Ecotope map; Intertidal mudflats; Jiangsu coast; Mapping; Migratory shorebirds; Reclamations; Tongzhou bay","en","journal article","","","","","","","","","","Hydraulic Engineering","Coastal Engineering","","",""
"uuid:f04b76a7-7402-4f6e-95ed-238119ef5f49","http://resolver.tudelft.nl/uuid:f04b76a7-7402-4f6e-95ed-238119ef5f49","Enhanced potential ecological risk induced by a large scale water diversion project","Yu, M. (TU Delft Water Resources; Hohai University; Research Center for Climate Change of Ministry of Water Resources); Wood, Paul (Loughborough University); van de Giesen, N.C. (TU Delft Water Resources); Liu, X. (TU Delft Hydraulic Structures and Flood Risk; IHE Delft Institute for Water Education); Li, Qiongfang (Hohai University); Wang, Guoqing (Research Center for Climate Change of Ministry of Water Resources); Zhang, Jianyun (Research Center for Climate Change of Ministry of Water Resources)","","2020","River regulation by the construction of reservoirs represents one of the greatest challenges to the natural flow regime and ecological health of riverine systems globally. The Danjiangkou (DJK) Reservoir is the largest reservoir on the Hangjiang River and commenced operations in 1967. The reservoir was upgraded in 2012 to provide water resource for the South–North water transfer project through central China. However, the effect of the reservoir operations on the downstream hydrological regime and ecological health of the Hanjiang River following the upgrade (increase in dam height and reservoir capacity) has not been examined thus far. The daily discharge series from four stations along the main stem of the Hanjiang River, including a site upstream, were examined from 1950 to 2017. The study series was divided into three periods based on the difference stages of the reservoir operation: (1) 1950–1966, (2) 1967–2012 and (3) 2013–2017. The nature of hydrological alteration, ecological flow requirement and potential ecological risk during the different periods were investigated. The results clearly indicate that the DJK reservoir has significantly modified the hydrological regime in the middle and downstream section of the Hanjiang River, with most significant modifications recorded immediately downstream of the reservoir. None of the observed ‘Range of Variability Approach’ hydrological indicators fell within the expected range at Huangjiagang following the increase in reservoir capacity. As a result, the ecological flow requirements could not be guaranteed, and the frequency and intensity of ecodeficit increased. The river ecosystem immediately downstream of the dam was observed to be at high risk of ecosystem degradation during the post-dam periods considered.","Danjiangkou reservoir; Ecodeficit; Ecological risk; Hydrological alteration; South–North water transfer project","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-02-24","","","Water Resources","","",""
"uuid:c05554e4-b3f4-48cf-9a8d-efde53a86f15","http://resolver.tudelft.nl/uuid:c05554e4-b3f4-48cf-9a8d-efde53a86f15","Interface chemistry of an amide electrolyte for highly reversible lithium metal batteries","Wang, Qidi (Tsinghua University); Yao, Zhenpeng (Harvard University); Zhao, Chenglong (Chinese Academy of Sciences); Verhallen, T.W. (TU Delft RST/Storage of Electrochemical Energy); Tabor, Daniel P. (Harvard University); Liu, M. (TU Delft RST/Storage of Electrochemical Energy); Ooms, F.G.B. (TU Delft RST/Technici Pool); Kang, Feiyu (Tsinghua University); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2020","Metallic lithium is a promising anode to increase the energy density of rechargeable lithium batteries. Despite extensive efforts, detrimental reactivity of lithium metal with electrolytes and uncontrolled dendrite growth remain challenging interconnected issues hindering highly reversible Li-metal batteries. Herein, we report a rationally designed amide-based electrolyte based on the desired interface products. This amide electrolyte achieves a high average Coulombic efficiency during cycling, resulting in an outstanding capacity retention with a 3.5 mAh cm−2 high-mass-loaded LiNi0.8Co0.1Mn0.1O2 cathode. The interface reactions with the amide electrolyte lead to the predicted solid electrolyte interface species, having favorable properties such as high ionic conductivity and high stability. Operando monitoring the lithium spatial distribution reveals that the highly reversible behavior is related to denser deposition as well as top-down stripping, which decreases the formation of porous deposits and inactive lithium, providing new insights for the development of interface chemistries for metal batteries.","OA-Fund TU Delft","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:4549cd3c-7488-4081-a791-6c57680063ec","http://resolver.tudelft.nl/uuid:4549cd3c-7488-4081-a791-6c57680063ec","Surface characterization of carbonated recycled concrete fines and its effect on the rheology, hydration and strength development of cement paste","Ouyang, Xiaowei (Guangzhou University); Wang, Liquan (Guangzhou University); Xu, Shida (Guangzhou University); Ma, Yuwei (Guangzhou University); Ye, G. (TU Delft Materials and Environment)","","2020","Carbonation treatment can effectively improve the performance of recycled concrete aggregate and fines due to the reactions of CO2 with CH and C–S–H gel of cement paste. To better understand the mechanisms involved in the performance improvement, the surface properties of carbonated recycled cement paste powder (CRP) and its effect on the rheology, hydration and strength development of cement paste was studied. The results showed that during the carbonation, the surface of CRP was covered by a layer of amorphous silica gel. The generated CaCO3 was wrapt by the silica gel and seldom exposed. The silica layer led to the poor flowability of CRP-cement paste due to that the silica gel on the surface of CRP has a strong affinity for H2O. During the very early hydration, the silica gel dissolved and then CaCO3 was exposed. CaCO3 is capable of chemically absorbing Ca2+, which facilitated the nucleation of C–S–H nuclei and stabilized the C–S–H phase. As a result, the C–S–H grew densely, uniformly and perpendicularly on the surface of CRP. In addition, the chemically absorbing Ca2+ enabled the chemical bond to be formed between CaCO3 and C–S–H. Due to increased C–S–H resulted from reactions of silica gel with CH at the interface and the stronger bond formed between CaCO3 and C–S–H, the interface between CRP and hydration products was much stronger than that between recycled cement paste powder (RP) and hydration products.","Carbonation treatment; Hydration; Recycled concrete aggregate; Recycled concrete fines; Rheology; Strength development","en","journal article","","","","","","Accepted Author Manuscript","","2022-09-11","","","Materials and Environment","","",""
"uuid:ec976b28-f98a-4ac5-a01e-b4241f07215d","http://resolver.tudelft.nl/uuid:ec976b28-f98a-4ac5-a01e-b4241f07215d","SmartVLC: Co-Designing Smart Lighting and Communication for Visible Light Networks","Wu, Hongjia (Simula Research Laboratory); Wang, Q. (Katholieke Universiteit Leuven); Xiong, Jie (University of Massachusetts Amherst); Zuniga, Marco (TU Delft Embedded Systems)","","2020","Visible Light Communication (VLC) based on LEDs has been a hot topic investigated for over a decade. However, most of the research efforts assume the intensity of LED light is constant. This hypothesis is not true when Smart Lighting is introduced to VLC, which requires LEDs to adapt their brightness based on the intensity of natural ambient light. Smart lighting saves power consumption and improves user comfort. However, intensity adaptation severely affects the throughput performance of data communication. In this paper, we propose SmartVLC, a system that can maximize the throughput (benefit communication) while still maintaining the LEDs' illumination function (benefit smart lighting). A novel Adaptive Multiple Pulse Position Modulation (AMPPM) scheme is proposed to support fine-grained dimming levels to avoid flickering while maximizing the throughput under each dimming level. SmartVLC is implemented on off-the-shelf commodity hardware. Several real-life challenges in both hardware and software are addressed to make it a robust real-time system. Comprehensive experiments are carried out to evaluate the system performance under multifaceted scenarios. Experimental results demonstrate that SmartVLC supports a communication distance up to 3.6m, and improves the throughput achieved with two state-of-the-art approaches by 40 and 12 percent on average, respectively, without bringing any flickering to users.","AMPPM; evaluation; flickering-free; illumination; implementation; system design; Visible light communication","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-08-17","","","Embedded Systems","","",""
"uuid:942fb134-ef1f-4aae-be2e-0953bdedd2a8","http://resolver.tudelft.nl/uuid:942fb134-ef1f-4aae-be2e-0953bdedd2a8","Controlling the Lithium-Metal Growth to Enable Low-Lithium-Metal-Excess All-Solid-State Lithium-Metal Batteries","Liu, M. (TU Delft RST/Storage of Electrochemical Energy); Wang, C. (TU Delft RST/Storage of Electrochemical Energy); Cheng, Z. (TU Delft RST/Storage of Electrochemical Energy); Ganapathy, S. (TU Delft RID/TS/Instrumenten groep); Haverkate, Lucas A. (TNO); Unnikrishnan, Sandeep (TNO); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2020","Solid-state lithium-metal batteries are considered to be promising candidates for next-generation high-energy density storage devices to power electrical vehicles. Critical challenges for solid-state lithium-metal batteries include the large morphological changes associated with the plating and stripping of lithium metal and decomposition of the solid electrolyte, because of the reductive nature of the lithium metal, both increasing the lithium metal-solid electrolyte interface resistance. This is especially challenging when starting in the discharged state with a bare anode or ""anode-less""current collector facing the solid electrolyte. To overcome this, a 100-nm thin layer of ZnO is deposited on the copper current collector with atomic layer deposition (ALD). During the first charge, this results in more homogeneous lithium-metal growth, rationalized by the formation of a Zn-Li alloy that acts as seed crystals for the lithium metal. The resulting more homogeneous lithium-metal growth maintains better contact with the solid electrolyte, leading to more reversible cycling of lithium metal. Minor prelithiating of the ZnO/Cu anode with 1 mAh/cm2 further improves the cycling performance, as demonstrated in a full all-solid-state cell using LiFePO4 as a cathode, resulting in an average Coulombic efficiency of >95%. These findings mark the first steps in an interface strategy to overcome the challenges at the solid electrolyte/lithium-metal interface in solid-state lithium-metal batteries.","","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:af7b272e-ecbe-4811-8d1e-a135af384d0e","http://resolver.tudelft.nl/uuid:af7b272e-ecbe-4811-8d1e-a135af384d0e","Variations in storm-induced bed level dynamics across intertidal flats","de Vet, P.L.M. (TU Delft Coastal Engineering; Deltares); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Colosimo, I. (TU Delft Environmental Fluid Mechanics); Steiner, N. (Universiteit Utrecht; NIOZ Royal Netherlands Institute for Sea Research); Ysebaert, T. (Universiteit Utrecht; Wageningen University & Research; NIOZ Royal Netherlands Institute for Sea Research); Herman, P.M.J. (TU Delft Environmental Fluid Mechanics; Deltares); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2020","Hydrodynamic forces on intertidal flats vary over a range of temporal and spatial scales. These spatiotemporal inhomogeneities have implications for intertidal flat morphodynamics and ecology. We determine whether storm events are capable of altering the long-term morphological evolution of intertidal flats, and unravel the contributions of tidal flow, wind-driven flow, waves, and water depth on inhomogeneities in bed level dynamics (bed level changes over ~days) across these areas. We complement decades of bed level measurements on eight intertidal flats in two estuaries in the Netherlands with an extensive 1-month field campaign on one of those flats. Across this intertidal flat, the hydrodynamics and morphodynamics of a storm event were captured, including the post-storm recovery. We show that individual events can persistently alter the morphological evolution of intertidal flats; magnitudes of some bed level changes are even comparable to years of continuous evolution. The morphological impacts of events are largely controlled by the relative timing of the forcing processes, and not solely by their magnitudes. Spatiotemporal variations in bed level dynamics of intertidal flats are driven by a combination of: (1) the inhomogeneous distributions of the hydrodynamic forcing processes (including the under-explored role of the wind); and (2) the linear proportionality between bed level dynamics and the local bed slope.","","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:b40ff9e6-c2a9-41f4-867b-752ffe540a04","http://resolver.tudelft.nl/uuid:b40ff9e6-c2a9-41f4-867b-752ffe540a04","Investigations of mixing technique on the rheological properties of self-compacting concrete","Li, Huajian (China Academy of Railway Sciences; State Key Laboratory of High Speed Railway Track Technology); Huang, Fali (China Academy of Railway Sciences; State Key Laboratory of High Speed Railway Track Technology); Yi, Zhonglai (China Academy of Railway Sciences; State Key Laboratory of High Speed Railway Track Technology); Wang, Zhen (China Academy of Railway Sciences; State Key Laboratory of High Speed Railway Track Technology); Zhang, Y. (TU Delft Materials and Environment; Fuzhou University); Yang, Zhengxian (Fuzhou University)","","2020","Rheological properties are of significant importance in successful placement and performance of self-compacting concrete (SCC). In this work, the rheological properties of SCC, combined with a powder-viscosity modifying admixture, were investigated based on a series of experimental studies. The modified Bingham model was applied to determine the rheological parameters and shear thickening behavior of SCC. The effects of mixing procedures, including charging sequence, mixing time and mixing speed, were analyzed. The results show that the shear thickening of SCC is reduced by first mixing the aggregate and water and then adding other raw materials. The direct contact between aggregate and water leads to a large amount of free water to be adsorbed by the aggregate system, resulting in an increase of the yield stress. In order to ensure an excellent fluidity and a low shear thickening behavior of SCC, the mixing time should be controlled at 4-5 min and the mixing speed at 30-45 r/min.","Charging sequence; Mixing speed; Mixing time; Rheological properties; Self-compacting concrete","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:881588cf-b872-4c6d-8735-8083fa1478ff","http://resolver.tudelft.nl/uuid:881588cf-b872-4c6d-8735-8083fa1478ff","An opportunistic maintenance strategy for offshore wind turbine system considering optimal maintenance intervals of subsystems","Li, M. (TU Delft Transport Engineering and Logistics; Harbin Engineering University); Wang, Mian (CSSC Cruise Technology Development); Kang, Jichuan (Harbin Engineering University; Naval Architecture and Offshore Technology); Sun, Liping (Harbin Engineering University); Jin, Peng (Harbin Engineering University)","","2020","Operation and maintenance (O&M) costs account for a large proportion of the total costs for offshore wind energy. Performing a reasonable maintenance strategy is an effective approach to reduce O&M costs and gain more profits. In this paper, an opportunistic maintenance strategy for offshore wind turbine systems considering maintenance intervals of each subsystem is proposed to minimize the total maintenance cost. First, a Non-homogeneous Continuous-Time Markov Process based state transition model is established to study degradation process of subsystems. The influence of maintenance time schedule on the maintenance cost is studied to obtain the optimal maintenance intervals of each subsystems. Then, an opportunistic maintenance model considering economic dependencies between multiple subsystems is proposed to optimize the maintenance strategy by combining maintenance activities of individual subsystems to a grouping maintenance activity. A numerical example is used to indicate the significant effectiveness of the maintenance model. The result shows that the total maintenance cost of an offshore wind turbine system will be reduced by adopting the opportunistic maintenance strategy when compared with conventional preventive maintenance strategy.","Cost-effective maintenance; Maintenance optimization; Offshore wind energy; Operation and maintenance","en","journal article","","","","","","Accepted Author Manuscript","","2022-09-21","","","Transport Engineering and Logistics","","",""
"uuid:4c92a6c2-0de6-4405-816e-6c5926b8e63e","http://resolver.tudelft.nl/uuid:4c92a6c2-0de6-4405-816e-6c5926b8e63e","A Bayesian Network Approach for Condition Monitoring of High-Speed Railway Catenaries","Wang, H. (TU Delft Railway Engineering); Nunez, Alfredo (TU Delft Railway Engineering); Liu, Zhigang (Southwest Jiaotong University); Zhang, Dongliang (Southwest Jiaotong University); Dollevoet, R.P.B.J. (TU Delft Railway Engineering)","","2020","The growing variety of data from condition monitoring of high-speed railways offer unprecedented opportunities to improve railway infrastructure maintenance. For condition monitoring of railway catenaries, this paper proposes a data-driven approach that uses a Bayesian network (BN) to integrate the inspection data from catenaries into a key performance indicator (KPI). The BN topology is structured based on the physical relationships among data types, including train speed, dynamic stagger and height of the contact wire, pantograph head acceleration, and pantograph-catenary contact force. The tailored performance indicators are individually defined and extracted from the five types of data as the BN input. As the output of the BN, the KPI is defined as the overall condition level of the catenary considering all defects that can be reflected by the data types. Finally, using historical inspection data and maintenance records from a section of the Beijing-Guangzhou high-speed line in China, the BN parameters are estimated to establish a probabilistic relationship between the input and output. An approach that applies the estimated BN to catenary condition monitoring is proposed. Testing of the BN-based approach using new inspection data shows that the output KPI can adequately represent the catenary condition, leading to a nearly 66.2% reduction in the false alarm rate of defect detection compared with current practice. It is also tested that when the input data quality is not ideal, the approach can still work acceptably on noisy data with a signal-to-noise ratio greater than 3 dB or with one type of data missing.","Bayesian network; catenary; condition monitoring; High-speed railway; inspection data; key performance indicator","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-04-30","","","Railway Engineering","","",""
"uuid:d37eace9-48fb-4ed9-9339-6397fcdedbaa","http://resolver.tudelft.nl/uuid:d37eace9-48fb-4ed9-9339-6397fcdedbaa","Planning Jerk-Optimized Trajectory with Discrete Time Constraints for Redundant Robots","Dai, C. (TU Delft Materials and Manufacturing; Chinese University of Hong Kong); Lefebvre, Sylvain (Institut National de Recherche en Informatique et en Automatique (INRIA)); Yu, Kai Ming (The Hong Kong Polytechnic University); Geraedts, Jo M.P. (TU Delft Mechatronic Design); Wang, C.C. (Chinese University of Hong Kong)","","2020","We present a method for effectively planning the motion trajectory of robots in manufacturing tasks, the tool paths of which are usually complex and have a large number of discrete time constraints as waypoints. Kinematic redundancy also exists in these robotic systems. The jerk of motion is optimized in our trajectory planning method at the meanwhile of fabrication process to improve the quality of fabrication. Our method is based on a sampling strategy and consists of two major parts. After determining an initial path by graph search, a greedy algorithm is adopted to optimize a path by locally applying adaptive filers in the regions with large jerks. The filtered result is obtained by numerical optimization. In order to achieve efficient computation, an adaptive sampling method is developed for learning a collision-indication function that is represented as a support-vector machine. Applications in robot-Assisted 3-D printing are given in this article to demonstrate the functionality of our approach. Note to Practitioners-In robot-Assisted manufacturing applications, robotic arms are employed to realize the motion of workpieces (or machining tools) specified as a sequence of waypoints with the positions of tool tip and the tool orientations constrained. The required degree of freedom (DOF) is often less than the robotic hardware system (e.g., a robotic arm has six-DOF). Specifically, rotations of the workpiece around the axis of a tool can be arbitrary (see Fig. 1 for an example). By using this redundancy, i.e., there are many possible poses of a robotic arm to realize a given waypoint, the trajectory of robots can be optimized to consider the performance of motion in velocity, acceleration, and jerk in the joint space. In addition, when fabricating complex models, each tool path can have a large amount of waypoints. It is crucial for a motion planning algorithm to compute a smooth and collision-free trajectory of robot to improve the fabrication quality. The time taken by the planning algorithm should not significantly lengthen the total manufacturing time; ideally, it would remain hidden as computing motions for a layer can be done while the previous layer is printing. The method presented in this article provides an efficient framework to tackle this problem. The framework has been well tested on our robot-Assisted additive manufacturing system to demonstrate its effectiveness and can be generally applied to other robot-Assisted manufacturing systems.","Discrete time constraints; kinematic redundancy; robotic fabrication; trajectory planning","en","journal article","","","","","","","","","","","Materials and Manufacturing","","",""
"uuid:6a758bf2-b94c-4971-a98e-e43a68686039","http://resolver.tudelft.nl/uuid:6a758bf2-b94c-4971-a98e-e43a68686039","Reinforced FDM: Multi-axis filament alignment with controlled anisotropic strength","Fang, G. (TU Delft Materials and Manufacturing); Zhang, Tianyu (Chinese University of Hong Kong); Zhong, Sikai (Wayne State University); Chen, Xiangjia (Chinese University of Hong Kong); Zhong, Zichun (Wayne State University); Wang, C.C. (The University of Manchester)","","2020","The anisotropy of mechanical strength on a 3D printed model can be controlled in a multi-axis 3D printing system as materials can be accumulated along dynamically varied directions. In this paper, we present a new computational framework to generate specially designed layers and toolpaths of multi-axis 3D printing for strengthening a model by aligning filaments along the directions with large stresses. The major challenge comes from how to effectively decompose a solid into a sequence of strength-aware and collision-free working surfaces. We formulate it as a problem to compute an optimized governing field together with a selected orientation of fabrication setup. Iso-surfaces of the governing field are extracted as working surface layers for filament alignment. Supporting structures in curved layers are constructed by extrapolating the governing field to enable the fabrication of overhangs. Compared with planar-layer based Fused Deposition Modeling (FDM) technology, models fabricated by our method can withstand up to 6.35× loads in experimental tests.","3D printing; anisotropic strength; multi-axis motion; reinforcement","en","journal article","","","","","","","","","","","Materials and Manufacturing","","",""
"uuid:9e8cc387-6a24-4ad0-ac0e-75f5d02bf11c","http://resolver.tudelft.nl/uuid:9e8cc387-6a24-4ad0-ac0e-75f5d02bf11c","Passive visible light networks: Taxonomy and opportunities","Wang, Q. (TU Delft Embedded Systems); Zuniga, Marco (TU Delft Embedded Systems)","","2020","Artificial lighting has been used mainly for illumination for more than a century. Only recently, we have started to transform our lighting infrastructure to provide new services such as sensing and communication. These advancements have two key requirements: the ability to modulate light sources (for data transmission) and the presence of photodetectors on objects (for data reception). These requirements assume that the system has direct control over the transmitter and receiver, as in any traditional communication system. But not all lights can be modulated, and most objects do not have photodetectors. To overcome these limitations, researchers are developing novel networks that (i) exploit passive light sources that cannot be directly modulated, such as the sun, and (ii) leverage reflections from the external surfaces of objects to create a new generation of sensing and communication networks with visible light that is sustainable and does not require active control over the system. In this survey, we propose a taxonomy to analyze state-of-the-art contributions. We also identify the overarching principles, challenges, and opportunities of this new rising area.","applications; opportunities; passive visible light communication; passive visible light sensing; taxonomy","en","conference paper","Association for Computing Machinery (ACM)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-08-17","","","Embedded Systems","","",""
"uuid:a86d95e0-17c4-4720-bc93-d8f49b14a9c1","http://resolver.tudelft.nl/uuid:a86d95e0-17c4-4720-bc93-d8f49b14a9c1","Sediment Connectivity: A Framework for Analyzing Coastal Sediment Transport Pathways","Pearson, S.G. (TU Delft Coastal Engineering; Deltares); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Elias, Edwin P.L. (USGS Pacific Coastal and Marine Science Center); Vitousek, Sean (USGS Pacific Coastal and Marine Science Center); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2020","Connectivity provides a framework for analyzing coastal sediment transport pathways, building on conceptual advances in graph theory from other scientific disciplines. Connectivity schematizes sediment pathways as a directed graph (i.e., a set of nodes and links). This study presents a novel application of graph theory and connectivity metrics like modularity and centrality to coastal sediment dynamics, exemplified here using Ameland Inlet in the Netherlands. We divide the study site into geomorphic cells (i.e., nodes) and then quantify sediment transport between these cells (i.e., links) using a numerical model. The system of cells and fluxes between them is then schematized in a network described by an adjacency matrix. Network metrics like link density, asymmetry, and modularity quantify system-wide connectivity. The degree, strength, and centrality of individual nodes identify key locations and pathways throughout the system. For instance, these metrics indicate that under strictly tidal forcing, sand originating near shore predominantly bypasses Ameland Inlet via the inlet channels, whereas sand on the deeper foreshore mainly bypasses the inlet via the outer delta shoals. Connectivity analysis can also inform practical management decisions about where to place sand nourishments, the fate of nourishment sand, or how to monitor locations vulnerable to perturbations. There are still open challenges associated with quantifying connectivity at varying space and time scales and the development of connectivity metrics specific to coastal systems. Nonetheless, connectivity provides a promising technique for predicting the response of our coasts to climate change and the human adaptations it provokes.","coastal sediment transport; graph theory; network analysis; sediment connectivity; sediment transport pathway; tidal inlet","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:e24abfab-0625-48e0-9be4-35d163b30bb3","http://resolver.tudelft.nl/uuid:e24abfab-0625-48e0-9be4-35d163b30bb3","A novel method for joint optimization of the sailing route and speed considering multiple environmental factors for more energy efficient shipping","Wang, K. (TU Delft Transport Engineering and Logistics; Dalian Maritime University); Li, Jiayuan (Dalian Maritime University); Huang, Lianzhong (Dalian Maritime University); Ma, Ranqi (Dalian Maritime University); Jiang, X. (TU Delft Transport Engineering and Logistics); Yuan, Yupeng (MOST; University of Cambridge); Mwero, Ngome A. (Dalian Maritime University); Negenborn, R.R. (TU Delft Transport Engineering and Logistics; MOST); Sun, Peiting (Dalian Maritime University); Yan, Xinping (MOST)","","2020","Energy saving and emission reduction have attracted a great deal of attention in the maritime industry. The optimization of a ship's energy efficiency can reduce energy consumption and CO2 emissions effectively. However, most of the available studies only focus on either the sailing speed or route optimization, and the interaction between speed and route under the influence of multiple environmental factors was not accounted properly. In this paper, a novel joint optimization method of the sailing route and speed, which considers the interaction between route and speed as well as multiple environmental factors, is proposed to fully exploit the energy efficiency's potential. Moreover, a joint optimization model of the sailing route and speed, which is based on an energy consumption model that considers multiple environmental factors, is established. Next, a solution algorithm for the joint optimization model is investigated in order to achieve joint decision-making with regard to the sailing route and speed. Finally, a case study is conducted that demonstrates the effectiveness of the proposed method. The results show that the proposed method can achieve the optimal sailing route and speed under complex environmental conditions, as well as a reduction in fuel consumption and CO2 emissions of about 4%.","CO emission; Energy consumption; Energy system; Route optimization; Speed optimization","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-03-02","","","Transport Engineering and Logistics","","",""
"uuid:ce7bf8d2-de2b-4e58-ab9e-820036e3fe6d","http://resolver.tudelft.nl/uuid:ce7bf8d2-de2b-4e58-ab9e-820036e3fe6d","Analysis on mechanical characteristics of welded joint with a new reinforced device in high-speed railway","Xiao, Hong (Beijing Jiaotong University); Yan, Dongwei (Beijing Jiaotong University); Liu, Guangpeng (Beijing Jiaotong University); Wang, Haoyu (TU Delft Mechanics and Physics of Structures)","","2020","High-speed railways adopt continuous welded rail to maintain the smoothness and continuity of the rail surface. However, the welded joint became one of the weakest parts. In order to clear the characteristics and mechanical properties of the new reinforced device, a dynamic three-dimensional vehicle-reinforced device-track coupling model is established. The mechanical characteristics of the track structure under high-speed train load were simulated and analyzed. After installing the new reinforced device, the dynamic response and service life of the track structure are obviously improved compared with the unreinforced rail. When the train speed is 300 km/h, the dynamic bending stress at the bottom of rail is reduced by 26.90%, the vertical and lateral acceleration of the rail are reduced by 42.78% and 21.56%, the vertical and lateral displacement of the rail are reduced by 6.36% and 8.67%, and the theoretical service life of the rail is greatly extended.","dynamic characteristics; fatigue life; high-speed railway; Reinforced device; welded joint","en","journal article","","","","","","","","","","","Mechanics and Physics of Structures","","",""
"uuid:6b6099c0-d0fa-4aca-9041-50a8f9e13aa1","http://resolver.tudelft.nl/uuid:6b6099c0-d0fa-4aca-9041-50a8f9e13aa1","Spin-orbit coupling and linear crossings of dipolar magnons in van der Waals antiferromagnets","Liu, J. (Beijing Normal University); Wang, L. (TU Delft QN/Akhmerov Group; Kavli institute of nanoscience Delft); Shen, Ka (Beijing Normal University)","","2020","A magnon spin-orbit coupling, induced by the dipole-dipole interaction, is derived in monoclinic-stacked bilayer honeycomb spin lattice with perpendicular magnetic anisotropy and antiferromagnetic interlayer coupling. Linear crossings are predicted in the magnon spectrum around the band minimum in Γ valley, as well as in the high-frequency range around the zone boundary. The linear crossings in K and K′ valleys, which connect the acoustic and optical bands, can be gapped when the intralayer dipole-dipole or Kitaev interactions exceed the interlayer dipole-dipole interaction, resulting in a phase transition from semimetal to insulator. Our results are useful for analyzing the magnon spin dynamics and transport properties in van der Waals antiferromagnets.","","en","journal article","","","","","","","","","","","QN/Akhmerov Group","","",""
"uuid:98b06910-2a4e-44f6-b341-ed144ffbd484","http://resolver.tudelft.nl/uuid:98b06910-2a4e-44f6-b341-ed144ffbd484","Susceptible-infected-spreading-based network embedding in static and temporal networks","Zhan, X. (TU Delft Multimedia Computing); Li, Z. (TU Delft Web Information Systems); Masuda, Naoki (University at Buffalo, State University of New York); Holme, Petter (Tokyo Institute of Technology); Wang, H. (TU Delft Multimedia Computing)","","2020","Link prediction can be used to extract missing information, identify spurious interactions as well as forecast network evolution. Network embedding is a methodology to assign coordinates to nodes in a low-dimensional vector space. By embedding nodes into vectors, the link prediction problem can be converted into a similarity comparison task. Nodes with similar embedding vectors are more likely to be connected. Classic network embedding algorithms are random-walk-based. They sample trajectory paths via random walks and generate node pairs from the trajectory paths. The node pair set is further used as the input for a Skip-Gram model, a representative language model that embeds nodes (which are regarded as words) into vectors. In the present study, we propose to replace random walk processes by a spreading process, namely the susceptible-infected (SI) model, to sample paths. Specifically, we propose two susceptible-infected-spreading-based algorithms, i.e., Susceptible-Infected Network Embedding (SINE) on static networks and Temporal Susceptible-Infected Network Embedding (TSINE) on temporal networks. The performance of our algorithms is evaluated by the missing link prediction task in comparison with state-of-the-art static and temporal network embedding algorithms. Results show that SINE and TSINE outperform the baselines across all six empirical datasets. We further find that the performance of SINE is mostly better than TSINE, suggesting that temporal information does not necessarily improve the embedding for missing link prediction. Moreover, we study the effect of the sampling size, quantified as the total length of the trajectory paths, on the performance of the embedding algorithms. The better performance of SINE and TSINE requires a smaller sampling size in comparison with the baseline algorithms. Hence, SI-spreading-based embedding tends to be more applicable to large-scale networks.","Link prediction; Network embedding; SI spreading process; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Multimedia Computing","","",""
"uuid:f5eb7406-ebf3-471b-860a-7fd97c989a72","http://resolver.tudelft.nl/uuid:f5eb7406-ebf3-471b-860a-7fd97c989a72","Reliability assessment of ultra-deep oil and gas wellbore casing using data statistics and numerical simulations","Yang, Shangyu (State Key Laboratory of Performance and Structural Safety for Petroleum Tubular Goods and Equipment Materials); Zhang, Renren (Xi'an University of Architecture and Technology); Wang, Jianjun (State Key Laboratory of Performance and Structural Safety for Petroleum Tubular Goods and Equipment Materials); Li, Xinhong (Xi'an University of Architecture and Technology); Fan, Heng (Xi'an Shiyou University); Yang, M. (TU Delft Safety and Security Science)","","2020","Ultra-deep oil and gas wells have become a new development trend in onshore oil and gas exploitation. However, Ultra-deep oil and gas wellbore casing is with high failure risk due to the harsh environment. It is essential to evaluate the reliability of wellbore casing. This paper assesses the operational reliability of wellbore casing using data statistics and numerical simulation. Firstly, the theoretical model for reliability analysis of wellbore casing is established, and the variables in the model are determined, including rock mechanics, cement ring, and casing string strength factors. Subsequently, considering the random distribution of model variables, many statistics and analyses are performed to determine the distribution parameters of the model variables. Eventually, Monte Carlo based numerical simulations are carried out to obtain the residual strength distribution and the reliability of wellbore casing. The production casing in the ultra-deep well with a depth of 6.5 km in China as an industrial case is used to illustrate the present study. It is observed that this study can be useful to guide a more accurate assessment of the reliability of ultra-deep wellbore casing.","Data statistics; Monte-carlo; Numerical model; Reliability assessment; Wellbore casing","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-06-13","","","Safety and Security Science","","",""
"uuid:71994566-6d40-462f-bf6d-b9fa297ee54b","http://resolver.tudelft.nl/uuid:71994566-6d40-462f-bf6d-b9fa297ee54b","A Local Particle Filter Using Gamma Test Theory for High-Dimensional State Spaces","Wang, Z. (TU Delft Water Resources); Hut, R.W. (TU Delft Water Resources); van de Giesen, N.C. (TU Delft Water Resources)","","2020","Particle filters are non-Gaussian filters, which means that the assumption that the error distribution of the ensemble should be Gaussian is unnecessary. Like the ensemble Kalman filter, particle filters are based on the Monte Carlo approximation to represent the distribution of model states. It requires a substantial number of particles to approximate the probability density function of states in high-dimensional models, which is prohibitive for real applications. In order to overcome problems with high dimensionality, localization was applied in an Ensemble-type data assimilation system. This study combines the localization in LETKF (Local Ensemble Transformation Kalman Filter) with particle filters and proposes a new local particle filter with the model state space correction using Gamma test theory for high-dimensional models. A series of tests with various parameter settings, including different the numbers of particles, observation intervals, localization scale, inflation factors, and observation operators, were used to evaluate the performance of this new method using a Lorenz model with 40 variables. Besides, the proposed filter was applied in the Lorenz model with 1,000 variables to evaluate its performance in the model with higher dimensions. The results show that this approach can deal with the issue of dimensionality, which otherwise leads to the collapse of the particle filters in high-dimensional systems. The local particle filter is stable and has considerable potential for complex higher-dimensional models.","data assimilation; Gamma test; high-dimensional models; localization; Lorenz model (1996); particle filters; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:6f7f8607-a052-448b-a393-7d5741abb46f","http://resolver.tudelft.nl/uuid:6f7f8607-a052-448b-a393-7d5741abb46f","Modelling the operation of vehicles at signalised intersections with special width approach lane based on field data","Zhao, J. (TU Delft Transport and Planning; University of Shanghai for Science and Technology); Kiptoo Kigen, Kevin (University of Shanghai for Science and Technology); Wang, M. (TU Delft Transport and Planning)","","2020","The intersection with special width approach lane (SWAL) is a newly proposed unconventional intersection design. A microscopic traffic flow model was proposed for describing the operation of vehicles at signalised intersections with SWAL. The operation process of driving on the SWAL was divided into four segments, including entering segment, transition segment, special width lane segment, and exiting segment. The car-following and lane selection behaviours of vehicles in these segments are analysed. The parameters used in the model were calibrated using the field data collected in Germany. The proposed model was realised in a time-discretised simulation. The sensitivity analyses of geometric, traffic, and signal factors were conducted. The results show that for the car-following behaviour, the passenger cars on the narrowed lanes cannot drive as efficient as on the normal width lane. For lane selection behaviour, it mainly depends on the distance between the two nearest vehicles in front of the two narrow lanes. The effectiveness of the SWAL depends on whether it is long enough to accommodate the queuing vehicles, which is a combined result of the layout design and the signal timing.","","en","journal article","","","","","","Accepted Author Manuscript","","","","","Transport and Planning","","",""
"uuid:4f2af618-318b-40d4-968f-0d4784e06a4d","http://resolver.tudelft.nl/uuid:4f2af618-318b-40d4-968f-0d4784e06a4d","Vibration Suppression Through Variable Stiffness and Damping Structural Joints","Wang, Qinyu (Eindhoven University of Technology); Senatore, Gennaro (Swiss Federal Institute of Technology); Jansen, K.M.B. (TU Delft Emerging Materials); Habraken, Arjan (Eindhoven University of Technology); Teuffel, Patrick (Eindhoven University of Technology)","","2020","This paper introduces a new semi-active strategy for vibration control of truss and frame structures equipped with variable stiffness and damping joints which consist of a shape memory polymer (SMP) core reinforced by an SMP-aramid composite skin. When the joints are actuated to the transition temperature through thermal actuation, the SMP core transitions from a glassy to a rubbery state through a viscoelastic region, which causes a stiffness reduction and an increase of damping. The mechanic behavior of the joint can be thought of as transitioning from a moment to a pin connection. This way, it is possible to cause a shift of the structure natural frequencies and to increase damping, which is employed to obtain a significant reduction of the dynamic response. This paper comprises two parts: (1) characterization of a variable stiffness and damping material model through experimental testing; (2) numerical simulations of a truss bridge and a four-story frame, which are equipped with variable stiffness and damping joints. The truss bridge (case A) is subjected to a resonance and a moving load while the four-story frame (case B) is subjected to El Centro earthquake loading. For case A under resonance loading, the dynamic response can be reduced exclusively through a frequency shift and ignoring viscoelastic effects. For case A under moving load and case B under earthquake loading, vibration suppression is mostly caused by the increase of damping due to viscoelastic effects. Control time delays due to joint heating have been included in the analysis. When the joints are actuated to the transition range 55°C–65°C, which is specific to the SMP adopted in this study, the acceleration peak amplitude reduces by up to 95% and 87%, for case A and case B, respectively. For both cases, damping increases by up to 2.2% from undamped conditions (25°C). This work has shown that the adoption of variable stiffness and damping structural joints has great potential to enable a new and effective semi-active control strategy to significantly reduce the structure response under a wide range of dynamic loading conditions.","adaptive structures; frequency shift; structural dynamics; variable stiffness and damping joint; vibration control; viscoelastic material","en","journal article","","","","","","","","","","","Emerging Materials","","",""
"uuid:07cad159-3012-4173-b173-f23ed77b6d81","http://resolver.tudelft.nl/uuid:07cad159-3012-4173-b173-f23ed77b6d81","Borehole research in New York State can advance utilization of low-enthalpy geothermal energy, management of potential risks, and understanding of deep sedimentary and crystalline geologic systems","Jordan, Teresa (Cornell University); Fulton, Patrick (Cornell University); Tester, Jefferson (Cornell University); Bruhn, D.F. (TU Delft Reservoir Engineering); Asanuma, Hiroshi (National Institute of Advanced Industrial Science and Engineering); Harms, Ulrich (VolcanoTectonics Junior Research Group); Wang, Chaoyi (Purdue University); Schmitt, Doug (Purdue University); Vardon, P.J. (TU Delft Geo-engineering)","","2020","In January 2020, a scientific borehole planning workshop sponsored by the International Continental Scientific Drilling Program was convened at Cornell University in the northeastern United States. Cornell is planning to drill test wells to evaluate the potential to use geothermal heat from depths in the range of 2700-4500 m and rock temperatures of about 60 to 120 °C to heat its campus buildings. Cornell encourages the Earth sciences community to envision how these boreholes can also be used to advance high-priority subsurface research questions. Because nearly all scientific boreholes on the continents are targeted to examine iconic situations, there are large gaps in understanding of the ""average"" intraplate continental crust. Hence, there is uncommon and widely applicable value to boring and investigating a ""boring"" location. The workshop focused on designing projects to investigate the coupled thermal-chemical-hydrological-mechanical workings of continental crust. Connecting the practical and scientific goals of the boreholes are a set of currently unanswered questions that have a common root: the complex relationships among pore pressure, stress, and strain in a heterogeneous and discontinuous rock mass across conditions spanning from natural to human perturbations and short to long timescales. The need for data and subsurface characterization vital for decision-making around the prospective Cornell geothermal system provides opportunities for experimentation, measurement, and sampling that might lead to major advances in the understanding of hydrogeology, intraplate seismicity, and fluid/chemical cycling. Subsurface samples could also enable regional geological studies and geobiology research. Following the workshop, the U.S. Department of Energy awarded funds for a first exploratory borehole, whose proposed design and research plan rely extensively on the ICDP workshop recommendations.","","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:2614350a-026a-488b-824d-a5eb52f9ae25","http://resolver.tudelft.nl/uuid:2614350a-026a-488b-824d-a5eb52f9ae25","Biogas productivity of anaerobic digestion process is governed by a core bacterial microbiota","Tao, Y. (TU Delft Sanitary Engineering; Imperial College London); Ersahin, M.E. (TU Delft Sanitary Engineering; Istanbul Technical University); Ghasimi, S.M.D. (TU Delft Sanitary Engineering; University of Kurdistan Hewlêr (UKH)); Ozgun, H. (TU Delft Sanitary Engineering; Istanbul Technical University); Wang, H. (TU Delft Sanitary Engineering); Zhang, X. (TU Delft Sanitary Engineering); Guo, Miao (Imperial College London); Yang, Yunfeng (Tsinghua University); Stuckey, David C. (Imperial College London); van Lier, J.B. (TU Delft Sanitary Engineering)","","2020","Anaerobic digestion (AD) has been commercially operated worldwide in full scale as a resource recovery technology underpinning a circular economy. However, problems such as a long start-up time, or system instability, have been reported in response to operational shocks. These issues are usually linked to the dynamics of the functional microbiota in AD. Exploring the microbiota-functionality nexus (MFN) could be pivotal to understand the reasons behind these difficulties, and hence improving AD performance. Here we present a systematic MFN study based on 138 samples taken from 20 well-profiled lab-scale AD reactors operated for up to two years. All the reactors were operated in the same lab within the same period of time using the same methodology to harvest physio-chemical and molecular data, including key monitoring parameters, qPCR, and 16S sequencing results. The results showed a core bacterial microbiota prevailing in all reactor types, including Bacillus, Clostridium, Bacteroides, Eubacterium, Cytophaga, Anaerophaga, and Syntrophomonas, while various methanogens dominated different communities due to different inocula origins, reactor temperatures, or salinity levels. This core bacterial microbiota well correlated with biogas production (Pearson correlation coefficient of 0.481, p < 0.0001). Such strong correlation was even comparable to that between the biogas production and the methanogenic 16S rRNA gene content (Pearson correlation coefficient of 0.481, p < 0.0001). The results indicated that AD performance only modestly correlated with microbial diversity, a key governing factor. AD microbiota was neither functionally redundant nor plastic, and a high variety in communities can exhibit a strong difference in reactor performance. Our study demonstrates the importance of a core bacterial microbiota in AD and supports inspiring considerations for design, bioaugmentation, and operational strategies of AD reactors in the future.","Anaerobic digestion; Biogas; Bioreactor; Microbiota","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-02-05","","","Sanitary Engineering","","",""
"uuid:635d7a4d-7fc0-45b4-9802-51924d7a64e9","http://resolver.tudelft.nl/uuid:635d7a4d-7fc0-45b4-9802-51924d7a64e9","Fast and robust low-rank approximation for five-dimensional seismic data reconstruction","Wu, Juan (Yangtze University, Wuhan); Bai, Min (Yangtze University, Wuhan); Zhang, D. (TU Delft ImPhys/Medical Imaging; TU Delft ImPhys/Computational Imaging); Wang, Hang (Zhejiang University); Huang, Guangtan (Zhejiang University); Chen, Yangkang (Zhejiang University)","","2020","Five-dimensional (5D) seismic data reconstruction becomes more appealing in recent years because it takes advantage of five physical dimensions of the seismic data and can reconstruct data with large gap. The low-rank approximation approach is one of the most effective methods for reconstructing 5D dataset. However, the main disadvantage of the low-rank approximation method is its low computational efficiency because of many singular value decompositions (SVD) of the block Hankel/Toeplitz matrix in the frequency domain. In this paper, we develop an SVD-free low-rank approximation method for efficient and effective reconstruction and denoising of the seismic data that contain four spatial dimensions. Our SVD-free rank constraint model is based on an alternating minimization strategy, which updates one variable each time while fixing the other two. For each update, we only need to solve a linear least-squares problem with much less expensive QR factorization. The SVD-based and SVD-free low-rank approximation methods in the singular spectrum analysis (SSA) framework are compared in detail, regarding the reconstruction performance and computational cost. The comparison shows that the SVD-free low-rank approximation method can obtain similar reconstruction performance as the SVD-based method but with a large computational speedup.","Low-rank approximation; Matrix completion; Multidimensional seismic data; Seismic data processing; Seismic reconstruction","en","journal article","","","","","","","","","","","ImPhys/Medical Imaging","","",""
"uuid:e18aaf5e-a7a9-43f3-8f9c-a010e99e9a24","http://resolver.tudelft.nl/uuid:e18aaf5e-a7a9-43f3-8f9c-a010e99e9a24","Receding horizon cooperative platoon trajectory planning on corridors with dynamic traffic signal","Liu, M. (TU Delft Transport and Planning); Hoogendoorn, S.P. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning)","","2020","In this paper, a trajectory control approach using model predictive control is proposed for cooperative (automated) vehicles. This control approach optimizes accelerations of the controlled connected and automated vehicle (CAV) platoon along a corridor with signalized intersections. The objectives of the proposed approach are to maximize the throughput first and optimize comfort, travel delay, and fuel consumption simultaneously after that. The throughput is determined according to the maximal number of CAVs that can pass the intersection during the green phase. Safety is included by penalizing smaller gaps between CAVs in the running cost. The red phase is taken into account as a virtual vehicle at the stop-line during the red time, thus the safe gap penalty with the virtual vehicle causes the first-stopping vehicle to decelerate or even stop facing the red phase. The acceleration and speed are constrained within the upper and lower bounds. The proposed approach is flexible in dealing with platoon merging, splitting, stopping, and queue-discharging characteristics at signalized intersections. Finally, the proposed control approach is verified by simulation under a baseline scenario and four scenarios, which consider signal settings and the anticipation of the red phase. The simulation results demonstrate the benefits of the proposed control approach on fuel savings, compared with the state-of-art approach which used the virtual vehicle term without anticipation. The adjustments of signal parameters in Scenario 3 and Scenario 4 demonstrate the applicability of the control approach under actuated signal control.","","en","journal article","","","","","","","","","","Transport and Planning","Transport and Planning","","",""
"uuid:c2d2e514-4523-498a-8b73-3221f9049665","http://resolver.tudelft.nl/uuid:c2d2e514-4523-498a-8b73-3221f9049665","Vertical greenery systems: From plants to trees with self-growing interconnections","Wang, X. (TU Delft Bio-based Structures & Materials); Gard, W.F. (TU Delft Bio-based Structures & Materials); Borska, Helena (Student TU Delft); Ursem, W.N.J. (TU Delft BT/Botanical Garden Delft); van de Kuilen, J.W.G. (TU Delft Bio-based Structures & Materials; Technische Universität München)","","2020","The integration of buildings into vegetation has become a necessity in many metropolitan areas of the world today. It expands the potential of vertical and horizontal, exterior and interior, exposed and enclosed spaces in a building that can be used to accommodate plants. Green infrastructures have benefits both on urban and building scales. They can be categorized into green roofs and vertical greenery systems that can be divided further into green façade, green wall, green terraces, elevated forest and vertical forest. There are many design and planting considerations for architects, structural engineers and botanists when using living architectures to mimic natural systems, such as plant characteristics and environmental conditions. Plants used for vertical greenery are more likely to be hardwood species to adjust solar radiation during cooling and heating periods, as well as for aesthetic pleasure. Take Bosco Verticale, which is located in Milan, as an example to look into engineering methods when trees grow on balconies of high-rise buildings. It can be concluded that planting restraint safety systems and regular maintenance are necessary for the tree growth in the sky. However, the change in growing conditions causes various problems such as stability and irregular growth of trees. Instead of using steel cables and cages to prevent trees from falling off in the sky, the concept of self-growing connections is proposed to act as natural bracings and provide the stability for vertical forests. This paper is meant to generate awareness of the possibilities of the vertical integration of trees into buildings, show application considerations, and inspire future developments.","","en","journal article","","","","","","","","","","","Bio-based Structures & Materials","","",""
"uuid:604759b0-e900-420e-a0da-81eef49154a9","http://resolver.tudelft.nl/uuid:604759b0-e900-420e-a0da-81eef49154a9","Organocatalytic Control over a Fuel-Driven Transient-Esterification Network","van der Helm, M. (TU Delft ChemE/Advanced Soft Matter); Wang, Chang Lin (Student TU Delft); Fan, B. (TU Delft ChemE/Advanced Soft Matter); Macchione, M. (TU Delft ChemE/Advanced Soft Matter); Mendes, E. (TU Delft ChemE/Advanced Soft Matter); Eelkema, R. (TU Delft ChemE/Advanced Soft Matter)","","2020","Signal transduction in living systems is the conversion of information into a chemical change, and is the principal process by which cells communicate. In nature, these functions are encoded in non-equilibrium (bio)chemical reaction networks (CRNs) controlled by enzymes. However, man-made catalytically controlled networks are rare. We incorporated catalysis into an artificial fuel-driven out-of-equilibrium CRN, where the forward (ester formation) and backward (ester hydrolysis) reactions are controlled by varying the ratio of two organocatalysts: pyridine and imidazole. This catalytic regulation enables full control over ester yield and lifetime. This fuel-driven strategy was expanded to a responsive polymer system, where transient polymer conformation and aggregation are controlled through fuel and catalyst levels. Altogether, we show that organocatalysis can be used to control a man-made fuel-driven system and induce a change in a macromolecular superstructure, as in natural non-equilibrium systems.","acetylation; chemical reaction networks; organocatalysis; out-of-equilibrium systems; polymers","en","journal article","","","","","","","","","","","ChemE/Advanced Soft Matter","","",""
"uuid:6d68dff5-9381-4488-a448-d15507340a94","http://resolver.tudelft.nl/uuid:6d68dff5-9381-4488-a448-d15507340a94","A multi-actor perspective on multi-objective regional energy system planning","Wang, N. (TU Delft Energie and Industrie); Heijnen, P.W. (TU Delft Energie and Industrie); Imhof, Pieter (Student TU Delft)","","2020","Renewable energy investment is a complex process where multiple actors are often involved with their own, sometimes conflicting, interests. Here we propose a multi-actor multi-objective regional energy system planning approach to help actors gain mutual understanding regarding each other’s optimal investment wishes, in order to advance the planning process. This approach combines two models: Multi-Objective Optimization (MOO) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The approach uses illustrative objectives and actors which is then applied to the greater Amsterdam region to showcase its usage and strength. The four chosen objectives, i.e. total Capital Expenditure, total Operation & Maintenance costs, land-use and visually impacted area are minimized simultaneously to obtain a set of Pareto-optimal solutions. These solutions are then evaluated for governments, funders and local residents with different preferences using TOPSIS. The case study shows that our approach is unique and useful when multiple actors have to decide together upon the energy investment capacities. It is able to provide quantitative and optimal decision-aiding from the multi-actor perspective and generate also sub-optimal yet acceptable solutions for all the actors. Based on our approach, the impacts of policy options can be revealed from the actors’ perspectives as well.","Energy system planning; Land-use; Multi-actor perspective; Multi-criteria decision-making; Multi-objective optimization; Visually impacted area","en","journal article","","","","","","","","","","","Energie and Industrie","","",""
"uuid:5accb495-1a6f-4cf1-9b97-8c03c1cfc38c","http://resolver.tudelft.nl/uuid:5accb495-1a6f-4cf1-9b97-8c03c1cfc38c","Uncertainty quantification of a real low-enthalpy geothermal reservoir","Wang, Y. (TU Delft Reservoir Engineering); Voskov, D.V. (TU Delft Reservoir Engineering; Stanford University); Daniilidis, Alexandros (TU Delft Reservoir Engineering); Khait, M. (TU Delft Reservoir Engineering); Saeid, S. (TU Delft Reservoir Engineering); Bruhn, D.F. (TU Delft Reservoir Engineering; Helmholtz Center Potsdam Gfz)","","2020","The efficient development of a geothermal field can be largely affected by the inherent geological and physical uncertainties. Besides, the uncertain operational and economic parameters can also impact the profit of a project. Systematic uncertainty quantification involving these parameters helps to determine the probability of concerning outputs. In this study, a low-enthalpy geothermal reservoir with strong heterogeneity, located in the West Netherlands Basin, is selected as the research area. Detailed geological model is constructed based on various static data including seismic and log interpretation. However, significant uncertainties still exist in definition of the model parameters, mainly reservoir permeability and porosity. Besides, the fluid properties have not been sampled in this field and can vary in the range between brackish to highly saline water. Also, the heat price and operational investment fluctuate with time and add up to uncertainty. Taking all interested parameters into consideration, the Monte Carlo method is utilized to select specific input data set. The forward simulations are powered by the GPU version of Delft Advance Research Terra Simulator (DARTS), which provides efficient simulation capabilities for geothermal applications. Through this investigation, a wide range of production temperature has been observed due to the uncertainty of the input parameters.","","en","conference paper","EAGE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-04-26","","","Reservoir Engineering","","",""
"uuid:42894883-22ba-49a7-94d2-14e69fa5c7bb","http://resolver.tudelft.nl/uuid:42894883-22ba-49a7-94d2-14e69fa5c7bb","Transient supramolecular hydrogels formed by catalytic control over molecular self-assembly","Wang, Hucheng (East China University of Science and Technology); Liu, Liqun (East China University of Science and Technology); Bai, Shengyu (East China University of Science and Technology); Guo, Xuhong (East China University of Science and Technology); Eelkema, R. (TU Delft ChemE/Advanced Soft Matter); van Esch, J.H. (TU Delft ChemE/Advanced Soft Matter); Wang, Y. (East China University of Science and Technology)","","2020","The present work shows how transient supramolecular hydrogels can be formed by catalytically controlled molecular self-assembly. Catalysis formation of molecular gelators leads the self-assembly along a kinetically favored pathway, resulting in transient hydrogels. This work demonstrates an effective approach towards pathway-dependent supramolecular materials.","","en","journal article","","","","","","Accepted Author Manuscript","","2021-09-22","","","ChemE/Advanced Soft Matter","","",""
"uuid:1452fd3f-a423-46a5-89da-6eb96b648948","http://resolver.tudelft.nl/uuid:1452fd3f-a423-46a5-89da-6eb96b648948","Dipolar spin waves in uniaxial easy-axis antiferromagnets: A natural topological nodal-line semimetal","Liu, J. (Beijing Normal University); Wang, L. (TU Delft QN/Akhmerov Group; Kavli institute of nanoscience Delft); Shen, Ka (Beijing Normal University)","","2020","The existence of magnetostatic surface spin waves in ferromagnets, known as the Damon-Eshbach mode, was recently demonstrated to originate from the topology of the dipole-dipole interaction. In this work, we study the topological characteristics of magnons in easy-axis antiferromagnets with uniaxial anisotropy. The dipolar spin waves are found to be, driven by the dipole-dipole interaction, in a topological nodal-line semimetal phase, which hosts Damon-Eshbach-type surface modes due to the bulk-edge correspondence. The long-wavelength character of dipolar spin waves makes our proposal valid for any natural uniaxial easy-axis antiferromagnet and, thus, enriches the candidates of topological magnonic materials. In contrast to the nonreciprocal property in the ferromagnetic case, surface modes with opposite momentum coexist at each surface, but with different chiralities. Such chirality-momentum or spin-momentum locking, similar to that of electronic surface states in topological insulators, offers the opportunity to design novel chirality-based magnonic devices in antiferromagnets.","","en","journal article","","","","","","","","","","","QN/Akhmerov Group","","",""
"uuid:d13a1a1c-1be0-49e5-9cc0-78da3e54780e","http://resolver.tudelft.nl/uuid:d13a1a1c-1be0-49e5-9cc0-78da3e54780e","Laboratory evaluation of the effects of long-term aging on high content polymer modified asphalt binder","Lin, P. (Tongji University); Huang, Weidong (Tongji University); Liu, X. (TU Delft Pavement Engineering); Apostolidis, P. (TU Delft Pavement Engineering); Wang, H. (TU Delft Pavement Engineering); Yan, Chuanqi (Tongji University)","","2020","One of the most widely used polymer-based modifiers in asphalt binders is styrene–butadiene–styrene (SBS), which results in binders of increased modulus, strength, toughness, and resistance to permanent deformation. These properties are further improved with the increase of SBS polymer content in asphalt binders, producing binders such as high-content polymer-modified asphalt (HCPMA). Although the HCPMA binders commonly are used in porous asphalt pavements, limited research has been conducted on their aging performance. This paper used gel permeation chromatography (GPC), Fourier transform infrared (FTIR) spectroscopy, and the dynamic shear rheometer (DSR) to explore the evolution of chemical and rheological properties of aging HCPMA binders. The study found that the aging of HCPMA is a combination of oxidation of the base asphalt binder and degradation of the SBS polymer, leading to modulus increase and phase angle decrease. The degradation of SBS happened mostly at the beginning and slowed after pressure-aging vessel (PAV) conditioning for 20 h, which resulted in the lowest rutting resistance of HCPMA binders. When SBS content was higher than 7.5%, more than half the SBS polymer remained after 80 h of PAV conditioning. Although the molecular weight of SBS decreased from 230,000 to 70,000 due to degradation, its modification effect was still significant. Moreover, high modification of SBS can retard the oxidation and hardening of base asphalt binder, especially after PAV conditioning for 20 h. Principal component analysis showed that 10 parameters used in this study could be explained by SBS content and asphalt binder aging extent. Based on PCA results, the complex modulus (G∗) and phase angle (δ) of HCPMA binders can be well fitted by the exponential function of SBS content and aging index.
A), FHR (fluid-like hydrocarbon, SB), and solid organic matter (SC). We propose a set of quantitative evaluation criterions comparing the results of pyrograms, for different types of the hydrocarbons, at different cleaning conditions. We showed that a modified pyrogram achieves complete cleaning with SA and SB removed while SC remains almost intact. The modified pyrogram achieves complete removal of FHR in the second stage of pyrogram, while earlier researches often report residual FHR. The introduced method improves the accuracy in the identification of production potential in kerogen-rich shale reservoirs up to about 3% of the total pore volume. Further, the new approach allows a quantitative assessment for the cleaning quality without altering the sample's organic matrix. Future studies on the petrophysical properties of the hydrocarbon-bearing reservoir rocks may benefit from the thorough hydrocarbon removal achieved through the modified pyrogram methods proposed in this study.","core cleaning; kerogen richness; modified pyrolysis method; quantitative evaluation; shale","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:3c0e4277-1aff-48ad-b72b-6926d2c876c2","http://resolver.tudelft.nl/uuid:3c0e4277-1aff-48ad-b72b-6926d2c876c2","Data-based Dynamic Condition Assessment of Railway Catenaries","Wang, H. (TU Delft Railway Engineering)","Dollevoet, R.P.B.J. (promotor); Nunez, Alfredo (copromotor); Delft University of Technology (degree granting institution)","2019","Railway catenary is the main infrastructure that delivers electric power for train operation. It is a structure commonly constructed along the railway line with contact wires suspended above the track. One or multiple pantographs mounted on the roof of a moving train collects electric current from the catenary through the sliding contact with a contact wire. With the increase of train speed and traffic density in recent years, the catenary is subject to higher impacts from pantographs, leading to critical failures such as the breakage of contact wire. This results in not only an increasing cost for reactive maintenance, but also disruptions of train service that affect many passengers.
To reduce the life cycle cost and failure rate of catenary in practice, planned and predictive maintenance is desired based on the condition monitoring of catenary. However, the monitoring data are underutilized to effectively assess the catenary condition and facilitate maintenance decision-making. This dissertation contributes in improving the dynamic condition assessment of catenary using the data from condition monitoring. New performance indicators (PIs) of catenary are defined in a way that is adaptive to the variations of monitoring data measured under different circumstances, such as the changes of catenary structure, pantograph type and train speed. The relationship between the monitoring data and the contact wire irregularities is studied using historical data and simulations. Data-based approaches are developed for the quantitative assessment of dynamic catenary condition.
First, an intrinsic wavelength contained in the pantograph-catenary contact force is identified and defined as the catenary structure wavelength (CSW). It is caused by the periodic variations of contact wire stiffness attributed to the cyclic structure of catenary that must regulate the height of contact wire in every spans and interdropper distances. An approach that adaptively extracts the CSWs of pantograph-catenary contact force is proposed based on the empirical mode decomposition algorithm. It extracts the CSW signals corresponding to the span lengths and interdropper distances, respectively, summing to form a characteristic signal of CSWs. The residual signal of the contact force excluding the CSWs is regarded as the non-CSW signal. The mean and standard deviation of the CSWs signal are used as PIs to indicate the condition of the main catenary geometric parameters. A PI based on the quadratic time-frequency representation of the non-CSW signal is proposed for detecting and localizing the local irregularities of contact wire. The proposed PIs are tested by simulation and measurement data and proven effective and adaptive owning to the use of CSWs and non-CSW signal.
Second, the concept of CSW is expanded to the pantograph head acceleration from which the CSWs and non-CSW signal can also be extracted using the same approach developed for the contact force. Considering the characteristics of pantograph head acceleration, the wavelet packet entropy of the CSWs and non-CSW signal is proposed as PIs for detecting contact wire irregularities with different lengths. The entropy of CSWs is used for detecting irregularities with a length longer than 5 m, while the entropy of non-CSW signal is for the short-length local irregularities. An approach to detect and verify contact wire irregularities using the measurement data of pantograph head vertical acceleration from frequent inspections is proposed. The approach is tested using historical inspection data from which irregularities at all lengths are detected and verified. Maintenance resources can thus be specifically allocated to verified detection results to save cost and time.
Third, through analyzing historical inspection data and data-based simulation results, it is found that while the contact wire irregularity deteriorates the pantograph-catenary interaction, the formation of irregularity is also associated with the effects of the interaction like variations of contact and friction forces. Concretely, the contact wire height irregularity with an amplitude of 8 mm can cause considerable increase in the standard deviation of pantograph-catenary contact force. In addition, the irregularity with a certain wavelength can induce the dynamic response with the same wavelength in the contact force. This in turn makes the irregularity part deteriorating faster than the other parts of catenary. At a smaller scale, when the wear irregularity of contact wire has an average wire thickness loss of about 1.5 mm, it can also increase the standard deviation of contact force by more than 5%. Due to the fixing effect at the registration arms and droppers, the wear irregularity commonly contains structural wavelengths of catenary including span lengths and interdropper distances. It is also found that the wear irregularity tends to grow and spread toward in the common or dominant running direction of trains in the specific line. Nevertheless, an existing defect may not affect every pantograph passage and every type of data measured. It is thus advised to measure multiple types of data and perform more frequent inspections to avoid undetected defects.
Last, a data-driven approach using the Bayesian network (BN) to fuse the available inspection data of catenary into an integrated PI is proposed. The BN topology is first structured based on the physical relations between five data types including the train speed, dynamic stagger and height of contact wire, pantograph head acceleration, and pantograph-catenary contact force. Then, tailored PIs are individually defined and extracted from the five types of data as the BN input. As the output of BN, an integrated PI is defined as the overall condition level of catenary considering all defects that can be reflected by the five types of data. Finally, using historical inspections data and maintenance records from a section of high-speed line, the BN parameters are estimated to establish a probabilistic relationship between the input and the output PI. By testing the BN-based approach using new inspection data from the same railway line, it is shown that the integrated PI can adequately represent the catenary condition, leading to considerable reduction in the false alarm rate of catenary defect detection compared with the current practice. The approach can also work acceptably with noisy or partly missing data.
In summary, this dissertation answers how to adequately transform the condition monitoring data of catenary into quantitative assessments of the dynamic catenary condition. The proposed approaches are intended for generic implementations in railway catenaries worldwide.","railway catenary; condition assessment; pantograph-catenary interaction; performance indicator; adaptive data processing; data-driven approach; catenary structure wavelength","en","doctoral thesis","","978-94-6323-962-2","","","","","","2019-11-18","","","Railway Engineering","","",""
"uuid:a07f9851-1949-43f8-ae79-9b4518a3f367","http://resolver.tudelft.nl/uuid:a07f9851-1949-43f8-ae79-9b4518a3f367","Workload-Adaptive Configuration Tuning for Hierarchical Cloud Schedulers","Han, Rui (Beijing Institute of Technology); Liu, Chi Harold (Beijing Institute of Technology); Zong, Zan (Tsinghua University); Chen, Lydia Y. (TU Delft Data-Intensive Systems); Liu, Wending (Beijing Institute of Technology); Wang, Siyi (Institute of Computing Technology Chinese Academy of Sciences); Zhan, Jianfeng (Institute of Computing Technology Chinese Academy of Sciences)","","2019","Cluster schedulers provide flexible resource sharing mechanism for best-effort cloud jobs, which occupy a majority in modern datacenters. Properly tuning a scheduler's configurations is the key to these jobs' performance because it decides how to allocate resources among them. Today's cloud scheduling systems usually rely on cluster operators to set the configuration and thus overlook the potential performance improvement through optimally configuring the scheduler according to the heterogeneous and dynamic cloud workloads. In this paper, we introduce AdaptiveConfig, a run-time configurator for cluster schedulers that automatically adapts to the changing workload and resource status in two steps. First, a comparison approach estimates jobs' performances under different configurations and diverse scheduling scenarios. The key idea here is to transform a scheduler's resource allocation mechanism and their variable influence factors (configurations, scheduling constraints, available resources, and workload status) into business rules and facts in a rule engine, thereby reasoning about these correlated factors in job performance comparison. Second, a workload-adaptive optimizer transforms the cluster-level searching of huge configuration space into an equivalent dynamic programming problem that can be efficiently solved at scale. We implement AdaptiveConfig on the popular YARN Capacity and Fair schedulers and demonstrate its effectiveness using real-world Facebook and Google workloads, i.e., successfully finding best configurations for most of scheduling scenarios and considerably reducing latencies by a factor of two with low optimization time.","Cloud datacenter; cluster scheduler; configuration; job latency; YARN","en","journal article","","","","","","","","","","","Data-Intensive Systems","","",""
"uuid:81cbbf9e-8e64-427b-840a-886bd0e2c769","http://resolver.tudelft.nl/uuid:81cbbf9e-8e64-427b-840a-886bd0e2c769","Delamination toughening in a low carbon microalloyed steel plate rolled in the dual-phase region","Shen, X. J. (Northeastern University); Li, D. Z. (Northeastern University); Tang, S. (Northeastern University); Chen, J. (Northeastern University); Fang, H. (TU Delft RST/Fundamental Aspects of Materials and Energy; TU Delft Novel Aerospace Materials); Wang, G. D. (Northeastern University)","","2019","It is still a big challenge to obtain excellent low-temperature toughness for bulk steel materials. Delamination is an effective method to improve low-temperature toughness. In the present study, delamination toughening in a low carbon microalloyed steel plate with elongated and ultrafine-grained microstructure rolled in the dual-phase region has been investigated in detail. When toughness was measured along normal direction, the steel plate had a high upper shelf energy and no delamination occurred in the upper shelf region. A large delaminated crack parallel to rolling plane started to appear and changed the propagation path of main crack when testing temperature was lower than −60 °C. We find this kind of delamination induces a second upper shelf in the Charpy transition–temperature curve. The second upper shelf, reaching up to 300 J in the temperature range of −60 °C to −140 °C, results in excellent low-temperature toughness for the steel plate, and the ductile-brittle transition temperature is lowered to −157 °C. The developed steel plate also has high low-temperature toughness measured along transverse direction due to delamination. The effect factors on upper shelf energy, delamination mechanism and delamination toughening are discussed.","Crystallographic texture; Delamination toughening; Elongated and ultrafine-grained microstructure; Steel plates","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-05-06","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:9f197186-0b19-4057-812c-4ef1db17c5db","http://resolver.tudelft.nl/uuid:9f197186-0b19-4057-812c-4ef1db17c5db","Matching images and text with multi-modal tensor fusion and re-ranking","Wang, Tan (University of Electronic Science and Technology of China); Hanjalic, A. (TU Delft Intelligent Systems); Xu, Xing (University of Electronic Science and Technology of China); Shen, Heng Tao (University of Electronic Science and Technology of China); Yang, Yang (University of Electronic Science and Technology of China); Song, Jingkuan (University of Electronic Science and Technology of China)","","2019","A major challenge in matching images and text is that they have intrinsically different data distributions and feature representations. Most existing approaches are based either on embedding or classification, the first one mapping image and text instances into a common embedding space for distance measuring, and the second one regarding image-text matching as a binary classification problem. Neither of these approaches can, however, balance the matching accuracy and model complexity well. We propose a novel framework that achieves remarkable matching performance with acceptable model complexity. Specifically, in the training stage, we propose a novel Multi-modal Tensor Fusion Network (MTFN) to explicitly learn an accurate image-text similarity function with rank-based tensor fusion rather than seeking a common embedding space for each image-text instance. Then, during testing, we deploy a generic Cross-modal Re-ranking (RR) scheme for refinement without requiring additional training procedure. Extensive experiments on two datasets demonstrate that our MTFN-RR consistently achieves the state-of-the-art matching performance with much less time complexity.","Cross-modal re-ranking; Image-text matching; Tensor fusion","en","conference paper","Association for Computing Machinery (ACM)","","","","","Accepted author manuscript","","","","Intelligent Systems","","","",""
"uuid:e6dda2cc-c117-40c0-bb58-41fbbb1bf5a3","http://resolver.tudelft.nl/uuid:e6dda2cc-c117-40c0-bb58-41fbbb1bf5a3","Vertical Forest Engineering: Applications of Vertical Forests with Self-Growing Connections in High-Rise Buildings","Wang, Xiuli (Delft University of Technology); Gard, Wolfgang (Delft University of Technology); van de Kuilen, J.W.G (Delft university of technology - Technical University of Munich)","","2019","Living architecture is thriving. The integration of buildings with vegetation has become a necessity in many metropolitan areas of the world today, including Singapore, New York City, Shanghai and Milan, to name a few. It expands the potential of vertical and horizontal, exterior and interior, exposed and enclosed spaces in a building that can be used to accommodate plants. Green infrastructures have benefits both on urban and building scales. They can be categorized into green roofs and vertical greenery systems that can be divided further into green façade, green/living wall, green terraces, elevated forests and vertical forests. There are many design and planting considerations for architects, structural engineers and botanists when using living architectures to mimic natural systems, such as climatic and regional considerations, primary functions and design objectives, structural support systems, maintenance, irrigation and so on. Plants used for vertical greenery are more likely to be hardwood species to adjust solar radiation during cooling and heating periods, and also for aesthetic pleasure. Take Bosco Verticale, which is located in Milan, as an example to look into engineering methods when trees grow on balconies of high rise buildings. It could be concluded that planting restraint safety system and regular maintenance are necessary for trees growing in the sky. But the change of growing conditions causes various problems such as stability and growth of trees. Instead of using steel cages and bracings to prevent falling off of trees in the sky, the concept of self-growing connections is proposed to provide the stability of vertical forests. This paper is meant to generate awareness of the possibilities of the integration of greenery vertically with buildings, show application considerations, and inspire future developments in typologies and integration with forests.","","en","conference paper","","","","","","","","","","","","","",""
"uuid:59d2590b-609b-4178-b2dd-960880c03994","http://resolver.tudelft.nl/uuid:59d2590b-609b-4178-b2dd-960880c03994","Vertical Forest Engineering: Applications of Vertical Forests with Self-Growing Connections in High-Rise Buildings: Poster presentation","Wang, Xiuli (Delft University of Technology); Gard, Wolfgang (Delft University of Technology); van de Kuilen, J.W.G (Delft university of technology - Technical University of Munich)","","2019","Living architecture is thriving. The integration of buildings with vegetation has become a necessity in many metropolitan areas of the world today, including Singapore, New York City, Shanghai and Milan, to name a few. It expands the potential of vertical and horizontal, exterior and interior, exposed and enclosed spaces in a building that can be used to accommodate plants. Green infrastructures have benefits both on urban and building scales. They can be categorized into green roofs and vertical greenery systems that can be divided further into green façade, green/living wall, green terraces, elevated forests and vertical forests. There are many design and planting considerations for architects, structural engineers and botanists when using living architectures to mimic natural systems, such as climatic and regional considerations, primary functions and design objectives, structural support systems, maintenance, irrigation and so on. Plants used for vertical greenery are more likely to be hardwood species to adjust solar radiation during cooling and heating periods, and also for aesthetic pleasure. Take Bosco Verticale, which is located in Milan, as an example to look into engineering methods when trees grow on balconies of high rise buildings. It could be concluded that planting restraint safety system and regular maintenance are necessary for trees growing in the sky. But the change of growing conditions causes various problems such as stability and growth of trees. Instead of using steel cages and bracings to prevent falling off of trees in the sky, the concept of self-growing connections is proposed to provide the stability of vertical forests. This paper is meant to generate awareness of the possibilities of the integration of greenery vertically with buildings, show application considerations, and inspire future developments in typologies and integration with forests.","","en","conference paper","","","","","","","","","","","","","",""
"uuid:6fed8ff8-ad7e-42cd-9a41-28846f1863f4","http://resolver.tudelft.nl/uuid:6fed8ff8-ad7e-42cd-9a41-28846f1863f4","Acoustic emission-based damage characterization of 70 MPa type IV hydrogen composite pressure vessels during hydraulic tests","Liao, B. B. (Zhejiang University); Wang, D. L. (Zhejiang University); Hamdi, M. (TU Delft Structural Integrity & Composites); Zheng, J. Y. (Zhejiang University); Jiang, P. (Zhejiang University; Northeast Petroleum University); Gu, C. H. (Zhejiang University); Hong, W. R. (Zhejiang University)","","2019","This paper aims to characterize the damage mechanisms of 70 MPa Type IV hydrogen composite pressure vessels using the acoustic emission (AE) method. First, AE signals were captured during the 0–105 MPa and 0–158 MPa hydraulic tests of two vessels using multi-step loading method. Second, the AE feature parameters in time-domain and frequency-domain such as amplitude, frequency, and energy are studied. A multi-parameter statistical analysis (MPSA) method based on empirical mode decomposition (EMD) and K-means algorithm is performed to cluster AE events for the vessels. Intrinsic mode functions (IMFs) are decomposed by EMD and three IMFs with high frequency are chosen to reconstruct the feature parameters and provide signal pre-processing for K-means clustering analysis. Based on the relationship between AE features and damage modes, three main clusters with separate amplitude, absolute energy, and energy are correlated to matrix cracking, fiber/matrix debonding, and fiber breakage damage mechanisms. Besides, the effectiveness of MPSA method for signal classification is validated by principal component analysis (PCA) and fast Fourier transformation (FFT) method. Finally, the AE feature parameters such as amplitude and counts to peak for the three main damage modes are studied for the hydraulic proof tests and the burst tests to explore the damage evolution behaviors of the vessels with pressure increasing. Results show that AE method can be reliably used to characterize damage evolution mechanisms in composite pressure vessels.","Damage evolution mechanisms; Damage modes recognition; Hydraulic tests; Hydrogen composite pressure vessel","en","journal article","","","","","","","","2021-08-10","","","Structural Integrity & Composites","","",""
"uuid:c8259a08-bbee-4af0-b570-1350a2dd8d89","http://resolver.tudelft.nl/uuid:c8259a08-bbee-4af0-b570-1350a2dd8d89","Incremental sliding mode flight control","Wang, Xuerui (TU Delft Control & Simulation)","Mulder, Max (promotor); van Kampen, E. (copromotor); Delft University of Technology (degree granting institution)","2019","The swift growth of air traffic volume stresses the importance of flight safety enhancement. Statistical data shows that fly-by-wire technology with automatic flight control systems can effectively reduce the fatal accident rate of loss of control in-flight. Although the dynamics of an aircraft are nonlinear and time-varying, it is common practice to design flight control laws based on local linear time-invariant (LTI) dynamic models, and apply gain-scheduling method. Here, the flight envelope is divided into many smaller operating regimes, and LTI model-based controllers are designed and tuned for each of them. However, this approach is cumbersome and cannot guarantee flight stability and performance in-between operational points. In view of the challenges encountered by LTI model-based control, nonlinear control methods have attracted attention from the flight control community. Nonlinear dynamic inversion (NDI) and backstepping (BS) are two frequently used nonlinear control methods in flight control. These two approaches cancel the nonlinearities in the closed loop using a nonlinear model of the system. However, mismatches between the model and real dynamics inevitability exist, especially when an aircraft encounters atmospheric disturbances and when sudden actuator faults or even structural damages occur. To enhance the robustness of model-based nonlinear control methods to model mismatches, a commonly adopted approach is to augment them with online model identification. This process, however, is computational intensive and requires sufficient excitation, which can make an impaired aircraft fly out of the diminished safe flight envelope. In consideration of these challenges, the main goal of this thesis is: To design a stability-guaranteed nonlinear flight control framework with reduced model dependency and enhanced robustness.","Incremental control; nonlinear control; fault-tolerant control; aeroservoelastic system; sliding mode control; sliding mode disturbance observer; quadrotor flight control","en","doctoral thesis","","978-94-6384-046-0","","","","","","","","","Control & Simulation","","",""
"uuid:7346f710-4474-44a3-8e67-164f2815abc2","http://resolver.tudelft.nl/uuid:7346f710-4474-44a3-8e67-164f2815abc2","Flexible Aircraft Gust Load Alleviation with Incremental Nonlinear Dynamic Inversion","Wang, Xuerui (TU Delft Control & Simulation); van Kampen, E. (TU Delft Control & Simulation); Chu, Q. P. (TU Delft Control & Simulation); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics)","","2019","This paper designs an incremental nonlinear dynamic inversion control law for free-flying flexible aircraft, which can regulate rigid-body motions, alleviate gust loads, reduce the wing root bending moment, and suppress elastic modes. By fully exploring the sensor measurements, the model dependency of the proposed control law can be reduced while maintaining desirable robustness, which simplifies the implementation process and reduces the onboard computational load. The elastic states are observed online from accelerometer measurements, with a Padé approximation to model the pure time delay. Theoretical analyses based on the Lyapunov methods and the nonlinear system perturbation theory show that the proposed control has inherent robustness to model uncertainties, external disturbances, and sudden actuator faults. These merits are demonstrated by time-domain simulations in various spatial turbulence and gust fields, as well as by a Monte Carlo study.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-05","","","Control & Simulation","","",""
"uuid:34cfdbae-a3ef-422d-9050-5cc2636ca82f","http://resolver.tudelft.nl/uuid:34cfdbae-a3ef-422d-9050-5cc2636ca82f","Where ergonomics meets geriatrics: The connection between comprehensive geriatric assessment and design for ageing","van der Cammen, T.J.M. (TU Delft Applied Ergonomics and Design; Erasmus MC); Wang, G. (TU Delft Applied Ergonomics and Design); Albayrak, A. (TU Delft Applied Ergonomics and Design)","","2019","","Ageing; Ergonomics; Human factors; Comprehensive geriatric assessment; Capability consideration; Technology","en","contribution to periodical","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-08-09","","","Applied Ergonomics and Design","","",""
"uuid:3761d7e1-90f3-432b-98d4-b773b4170312","http://resolver.tudelft.nl/uuid:3761d7e1-90f3-432b-98d4-b773b4170312","Experimental and numerical study on behaviour of square steel tube confined reinforced concrete stub columns after fire exposure","Liu, Faqi (Harbin Institute of Technology); Yang, Hua (Harbin Institute of Technology); Yan, R. (TU Delft Steel & Composite Structures); Wang, Wei (Harbin Institute of Technology)","","2019","The behaviour of square steel tube confined reinforced concrete columns after fire exposure was studied experimentally and numerically in this paper. Eighteen stub columns were first heated following the ISO 834 standard fire including both heating and cooling phases, and were subsequently loaded to failure after cooling to ambient temperature. Failure modes, temperatures in specimens, axial load versus deformation curves and strains in steel tube were monitored and discussed. A finite element model was developed using the sequentially coupled thermal-stress analysis method and was validated against tests found in literatures and this study. Parametric study was performed to identify influences of key parameters, where are heating time, cross-sectional dimension, strengths of materials, steel tube to concrete area ratio and reinforcement ratio, on residual capacity and compressive stiffness. Finally, a simplified method is proposed for predicting residual cross-sectional capacity and compressive stiffness of square steel tube confined reinforced concrete columns after fire exposure.","Compressive stiffness; Numerical simulation; Post-fire; Residual capacity; Square steel tube confined reinforced concrete; Test","en","journal article","","","","","","Accepted Author manuscript","","2021-03-06","","","Steel & Composite Structures","","",""
"uuid:c0d6a2ef-5341-4c8e-9cee-fc948e1acb89","http://resolver.tudelft.nl/uuid:c0d6a2ef-5341-4c8e-9cee-fc948e1acb89","Strain-based methodology for mixed-mode I plus II fracture: A new partitioning method for bi-material adhesively bonded joints: A new partitioning method for bi-material adhesively bonded joints","Moreira Arouche, M. (TU Delft Structural Integrity & Composites; Federal centre for technological education of Rio de Janeiro); Wang, W. (TU Delft Structural Integrity & Composites); Teixeira De Freitas, S. (TU Delft Structural Integrity & Composites); de Barros, Silvio (Université de Nantes; Federal centre for technological education of Rio de Janeiro)","","2019","The dissemination of composite materials introduces applications of hybrid structures with composite and metal parts. The development of reliable methodologies to evaluate the performance of these structures is required. In this work, the mixed-mode fracture behaviour of a bi-material adhesively bonded joint is investigated. A new strain-based criterion for the design of the mixed-mode bending (MMB) bi-material specimen is suggested. A new analytical partitioning method based on the ‘global method’ is proposed and tested on a composite-to-metal bonded joint and compared with a finite element model using the virtual crack closure technique (VCCT). The results show that the proposed strain-based design methodology can be successfully used in MMB test for bi-material joints. The fracture mode partitioning is accurately predicted by the analytical method. However, the absolute values of the strain energy release rate (SERR) predicted by the analytical method are only accurate if the shear deformation in the test is not significant.","analytical models; composites; finite element analysis; Fracture mechanics; mixed-mode fracture; MMB test","en","journal article","","","","","","","","2020-02-01","","","Structural Integrity & Composites","","",""
"uuid:5ee86b87-8b0e-4aca-b95f-4d77447679e2","http://resolver.tudelft.nl/uuid:5ee86b87-8b0e-4aca-b95f-4d77447679e2","Design of air traffic control weather related training program","Pierson, E. (The University of Akron); Ling, C. (The University of Akron); Alshaqah, A. (The University of Akron); James, J. (The University of Akron); Wang, S. (The University of Akron)","","2019","Essential components of a new scenario-based air traffic control (ATC) training platform whose effectiveness is being analyzed are outlined with respect to its use in the decision-making skills of trainees when confronted with emergency situations. The custom designed platform allows the trainee to interact with the program such that the 10-minute ramification of a proposed aircraft redirection can be explored visually before a decision is made. Actual previous extreme weather incidences are used. Testing of the platform is ongoing with ATC students from Kent State University. Data from subjective pre- and postquestionnaires as well as objective decision parameters are currently being taken.","","en","conference paper","","","","","","","","","","","","","",""
"uuid:efc1f7e2-6296-4ad5-90d9-f0ab77ba7ac2","http://resolver.tudelft.nl/uuid:efc1f7e2-6296-4ad5-90d9-f0ab77ba7ac2","Factors affecting air traffic controller’s weather dissemination to pilots","Alshaqah, A. (University of Akron); Ling, C. (University of Akron); Pierson, E. (University of Akron); Wang, S. (University of Akron)","","2019","As the number of flights in the United States continues to rise steadily, an equally amplified need for reliability and safety has come to the forefront of aviation research. One of the most alarming trends is the number of general aviation (GA) accidents during severe weather events that occur yearly, with fatalities occurring in more than half of these cases. This study focuses on identifying factors influencing weather dissemination of Air Traffic Controllers (ATC) to GA pilots. Ten factors affecting controllers’ performance during severe weather events were identified through an in-depth literature review including controller mental workload, situation awareness, weather information format and accuracy, weather information needs, weather tool limitations, inaccurate assumption and bias, controller training and expereince, regulatory factor, supervisory factors, and pilot-controller relationship. Recommendation can be developed to address each factors so that aviation safety could be enhanced in severe weather situations.","","en","conference paper","","","","","","","","","","","","","",""
"uuid:b922a199-9de9-4921-be92-2c767c8fb374","http://resolver.tudelft.nl/uuid:b922a199-9de9-4921-be92-2c767c8fb374","Practical experience of sensitivity analysis: Comparing six methods, on three hydrological models, with three performance criteria","Wang, Anqi (Hohai University); Solomatine, D.P. (TU Delft Water Resources; IHE Delft Institute for Water Education; Russian Academy of Sciences)","","2019","Currently, practically no modeling study is expected to be carried out without some form of Sensitivity Analysis (SA). At the same time, there is a large number of various methods and it is not always easy for practitioners to choose one. The aim of this paper is to briefly review main classes of SA methods, and to present the results of the practical comparative analysis of applying them. Six different global SA methods: Sobol, eFAST (extended Fourier Amplitude Sensitivity Test), Morris, LH-OAT, RSA (Regionalized Sensitivity Analysis), and PAWN are tested on three conceptual rainfall-runoff models with varying complexity: (GR4J, Hymod, and HBV) applied to the case study of Bagmati basin (Nepal). The methods are compared with respect to effectiveness, efficiency, and convergence. A practical framework of selecting and using the SA methods is presented. The result shows that, first of all, all the six SA methods are effective. Morris and LH-OAT methods are the most efficient methods in computing SI and ranking. eFAST performs better than Sobol, and thus it can be seen as its viable alternative for Sobol. PAWN and RSA methods have issues of instability, which we think are due to the ways Cumulative Distribution Functions (CDFs) are built, and using Kolmogorov-Smirnov statistics to compute Sensitivity Indices. All the methods require sufficient number of runs to reach convergence. Difference in efficiency of different methods is an inevitable consequence of the differences in the underlying principles. For SA of hydrological models, it is recommended to apply the presented practical framework assuming the use of several methods, and to explicitly take into account the constraints of effectiveness, efficiency (including convergence), ease of use, and availability of software.","Bootstrapping resample; Global Sensitivity Analysis; Hydrological model","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:c71f55e1-9049-47ae-85ba-cda251757064","http://resolver.tudelft.nl/uuid:c71f55e1-9049-47ae-85ba-cda251757064","Self-Sorting and Directed Molecular Self-Assembly towards New Soft Materials","Wang, Y. (TU Delft ChemE/Advanced Soft Matter)","van Esch, J.H. (promotor); Eelkema, R. (promotor); Delft University of Technology (degree granting institution)","2019","Molecular self-assembly has been realized as a powerful approach to control the organization of materials from molecular to macroscopic length scale. While for a long time molecular self-assembly has focused on the investigation of systems involving a single component and under thermodynamic equilibrium. In recent years the interests are shifting towards more complex multicomponent and non-equilibrium self-assembly systems, where the richest functions of the resulted supramolecular objects can be harnessed. In this thesis, multicomponent supramolecular self-assembly and directed molecular self-assembly leading to out-of-equilibrium supramolecular systems are investigated, with the aim to construct new soft functional materials.","","en","doctoral thesis","","","","","","","","","","","ChemE/Advanced Soft Matter","","",""
"uuid:b9fefd3f-a9fc-45ba-8c6b-ef30361ca341","http://resolver.tudelft.nl/uuid:b9fefd3f-a9fc-45ba-8c6b-ef30361ca341","SlimML: Removing Non- critical Input Data in Large-scale Iterative Machine Learning","Han, Rui (Beijing Institute of Technology); Liu, Chi Harold (Beijing Institute of Technology); Li, Shilin (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Dataintensive Systems); Wang, Guoren (Beijing Institute of Technology); Tang, Jian (DiDi AI Labs); Ye, Jieping (DiDi AI Labs)","","2019","The core of many large-scale machine learning (ML) applications, such as neural networks (NN), support vector machine (SVM), and convolutional neural network (CNN), is the training algorithm that iteratively updates model parameters by processing massive datasets. From a plethora of studies aiming at accelerating ML, being data parallelization and parameter server, the prevalent assumption is that all data points are equivalently relevant to model parameter updating. In this article, we challenge this assumption by proposing a criterion to measure a data point's effect on model parameter updating, and experimentally demonstrate that the majority of data points are non-critical in the training process. We develop a slim learning framework, termed SlimML, which trains the ML models only on the critical data and thus significantly improves training performance. To such an end, SlimML efficiently leverages a small number of aggregated data points per iteration to approximate the criticalness of original input data instances. The proposed approach can be used by changing a few lines of code in a standard stochastic gradient descent (SGD) procedure, and we demonstrate experimentally, on NN regression, SVM classification, and CNN training, that for large datasets, it accelerates model training process by an average of 3.61 times while only incurring accuracy losses of 0.37 percent.","Iterative machine learning; MapReduce; large input datasets; model parameter updating","en","journal article","","","","","","","","","","","Dataintensive Systems","","",""
"uuid:800401f1-e9d4-4226-8c9e-f5bd5531b088","http://resolver.tudelft.nl/uuid:800401f1-e9d4-4226-8c9e-f5bd5531b088","Quantum error correction with the toric Gottesman-Kitaev-Preskill code","Vuillot, C. (TU Delft QCD/Terhal Group); Asasi, Hamed (University of California); Wang, Y. (TU Delft QCD/Terhal Group); Pryadko, Leonid P. (University of California); Terhal, B.M. (TU Delft QCD/Terhal Group; TU Delft Quantum Computing; JARA Institute for Quantum Information)","","2019","We examine the performance of the single-mode Gottesman-Kitaev-Preskill (GKP) code and its concatenation with the toric code for a noise model of Gaussian shifts, or displacement errors. We show how one can optimize the tracking of errors in repeated noisy error correction for the GKP code. We do this by examining the maximum-likelihood problem for this setting and its mapping onto a 1D Euclidean path-integral modeling a particle in a random cosine potential. We demonstrate the efficiency of a minimum-energy decoding strategy as a proxy for the path integral evaluation. In the second part of this paper, we analyze and numerically assess the concatenation of the GKP code with the toric code. When toric code measurements and GKP error correction measurements are perfect, we find that by using GKP error information the toric code threshold improves from 10% to 14%. When only the GKP error correction measurements are perfect we observe a threshold at 6%. In the more realistic setting when all error information is noisy, we show how to represent the maximum likelihood decoding problem for the toric-GKP code as a 3D compact QED model in the presence of a quenched random gauge field, an extension of the random-plaquette gauge model for the toric code. We present a decoder for this problem which shows the existence of a noise threshold at shift-error standard deviation σ0 ≈ 0.243 for toric code measurements, data errors and GKP ancilla errors. If the errors only come from having imperfect GKP states, then this corresponds to states with just four photons or more. Our last result is a no-go result for linear oscillator codes, encoding oscillators into oscillators. For the Gaussian displacement error model, we prove that encoding corresponds to squeezing the shift errors. This shows that linear oscillator codes are useless for quantum information protection against Gaussian shift errors.","","en","journal article","","","","","","","","","","","QCD/Terhal Group","","",""
"uuid:73830b2c-deb1-4da9-b19c-5e848c5cfa4d","http://resolver.tudelft.nl/uuid:73830b2c-deb1-4da9-b19c-5e848c5cfa4d","Measurement, Assessment, Analysis and Improvement of Transition Zones in Railway Track","Wang, Haoyu (TU Delft Railway Engineering)","Dollevoet, R.P.B.J. (promotor); Markine, V.L. (copromotor); Delft University of Technology (degree granting institution)","2019","Transition zones in railway tracks are locations with considerable changes in the vertical stiffness of the track support, which can be found near bridges, culverts and tunnels. In such locations, the stiffness variation and the differential settlement of tracks (uneven settlement of the track on the embankment and of the engineering structure) result in amplification of the dynamic track forces. This amplification speeds up the degradation of ballast and subgrade, ultimately resulting in deterioration of the vertical track geometry, which can lead to deterioration of the passenger’s comfort, failure of the track components, and in extreme cases to train derailment. Therefore, the track maintenance in transition zones requires substantial effort, up to eight times more effort than on open tracks (i.e. ballast tracks without any special elements).
Although the poor performance of the track in transition zones is frequently reported, the transition zones have not been paid enough attention. First of all, there is no specific experimental method for assessment of the track condition in transition zones. Therefore, the transition zones are usually treated as open tracks during inspections. Secondly, the effect of the differential settlement (one of the factors causing the transition zone problem) on the track degradation has not been sufficiently studied as compared to the effects of the stiffness variation. Also, due to the insufficient knowledge on the track behaviour in transition zones, the track settlement in transition zones cannot be predicted precisely. As a result, the maintenance is performed in a reactive way. Finally, although many countermeasures have been proposed for transition zones, the tools for assessment of their performance (especially on a long term) are still lacking, which causes difficulties for track designers when selecting the countermeasures. Clearly, the knowledge on the measurement, dynamic behaviour, degradation, and assessment of the track in transition zones should be improved.
This study intended to give answers to the following questions: (1) How to assess the condition of the tracks in transition zones? using which tool? (2) Which factor contributes more to the track degradation in transition zones, the uneven settlement or the stiffness variation? (3) How to predict the track settlement in transition zones on a long term? (4) How to assess the performance of the countermeasures for transition zones?
In attempt to answer these questions, an integrated methodology combing an innovative experimental method and numerical model for analysis of the dynamic behaviour and degradation of railway tracks in transition zones has been developed. The methodology consists of the following three parts:
- An advanced measurement technique based on the DIC (Digital Image Correlation) method that is used to measure the absolute dynamic displacements of rails/sleepers due to the passing trains. The advantage of this technique is that the vertical track displacements are measured simultaneously at multiple points, allowing obtaining the dynamic profile of the track section. Also, no track possession is required during the measurement. The measurement technique provides a basis for assessment of the track condition in the transition zones.
- A novel model for analysis of the dynamic responses in transition zones that uses the explicit Finite Element (FE) method. The track model accounts for both the vertical stiffness variation and the differential track settlement in transition zones. The nonlinear contact elements are used to model the sleeper-ballast interface, which allows the sleeper-ballast interaction to more realistically be described as compared to the existing models.
- A novel procedure to predict the long-term track behaviour (settlement) in transition zones, which is based on the developed FE model of the transition zones and an empirical settlement model of ballast (developed by Y. Sato). Using this procedure, the track settlement in transition zones due to multiple passages of trains can be predicted, which can provide a basis for planning track maintenance in transition zones.
To demonstrate the developed methodology, it was used in a number of applications in this study such as:
- Assessment of the track condition in various transition zones,
- Numerical analysis of the track behaviour and of the factors influencing initiation and propagation of the track settlement in transition zones,
- Assessment of the performance of various countermeasures for transition zones.
Some additional studies on the effect of the moisture condition on track performance in transition zones and on the feasibility of using satellite radar for structural health monitoring of transition zones have been performed as well. The main conclusions of these studies can be summarised as follow:
o The numerical and experimental results confirmed the higher degradation of the track near engineering structures in transition zones as compared to the open track observed in situ.
o The track degradation and the length of the settlement affected zone in the Embankment-Bridge (EB) and the Bridge-Embankment (BE) transitions, which is defined by the train moving direction, are different. That was confirmed by the measurement and numerical results, and by field observations. This phenomenon was explained using the numerical model, namely that the initial location of the track settlement in the EB transition is primarily defined by the pitch motion of the bogies, while in the BE transition it is affected by the ‘gliding’ and ‘bouncing’ motion of the vehicle. The settlement affected zone in the BE transition is longer (depending on the velocity, approx. 2 times for 140 km/h) than the EB transition.
o The track condition in transition zones was successfully assessed using the measurement method. The condition assessment results have good correlation with maintenance history, and satellite data of the considered transition zones.
o The performance of various countermeasures for transition zones was successfully assessed using the developed methodology. The numerical results have shown that the sleepers with modified dimensions (preventive countermeasure) and the adjustable fasteners (corrective countermeasure) can significantly improve the track performance, 51% reduction in ballast stress and 93% reduction in the wheel-rail contact force respectively.
Using the integrated methodology, the research questions have been answered. The proposed methodology provides suitable tools for measurement, assessment, analysis and improvement of the tracks in transition zones. The methodology can be further applied to the design and optimisation of the track in transition zones.","Transition zone; Measurement; Finite Element Method (FEM); Degradation; Prediction; Countermeasure","en","doctoral thesis","","9789463235396","","","","Haoyu Wang was on born in Shenyang, China in 1987. He received a bachelor’s degree in civil engineering and a master’s degree in railway engineering at Beijing Jiaotong University (Beijing, China). He joined the railway section of Delft University of Technology (Delft, the Netherlands) for PhD research in 2011 and worked partly as a teaching assistant in 2015 and 2016. In 2017, he worked as a consultant/railway specialist in Roadscanners (Tampere, Finland). Since 2018, he has worked as a developer/railway specialist in Fugro (Utrecht, the Netherlands). He is specialised in researching and solving problems in the railway industry, focusing on the track structure analysis, condition monitoring, and quality evaluation.","","","","","Railway Engineering","","",""
"uuid:7d912f69-47d5-4f2e-9f8c-b6a6721adb55","http://resolver.tudelft.nl/uuid:7d912f69-47d5-4f2e-9f8c-b6a6721adb55","Indentation hardness, plasticity and initial creep properties of nanosilver sintered joint","Zhang, H. (TU Delft Electronic Components, Technology and Materials; Harbin University of Science and Technology); Liu, Y. (TU Delft Electronic Components, Technology and Materials; Harbin University of Science and Technology); Wang, Lingen (Boschman Technologies); Sun, Fenglian (Harbin University of Science and Technology); Fan, Xuejun (Lamar University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2019","The nanoindentation test was conducted in this paper to investigate the indentation hardness, plasticity and initial creep properties of pressure sintered nanosilver joint at various test temperatures. The effects of strain rate on the indentation hardness were first investigated. Then yield stress of nanosilver sintered joint was studied in various pressures sintered joints and the corresponding plastic stress-strain constitutive equations were gained. The maximum indentation depth of nanosilver sintered joint was obviously affected by the test temperature and sintering pressure. The indentation hardness of nanosilver sintered joint decreased with increasing test temperature from 140 to 200°C, which can be attributed to the increased amount of thermal vacancies at high temperatures. However, the indentation modulus exhibited decrease trend as the temperature increased. It is suggested that the distance between adjacent atoms was enlarged at elevated temperatures and furtherly resulted in the decrease of indentation modulus. In addition, the increased sintering pressure from 5 to 30 MPa improved the indentation hardness and modulus of sintered joint. The initial creep was observed in nanosilver sintered joint at temperatures ranged from 140 to 200°C. The increase of sintering pressure improved the resistance to creep of nanosilver sintered joint.","Indentation hardness; Initial creep; Nanosilver; Plastic deformation; Sintering pressure; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:54e41f8c-4ba6-454d-9f87-6471cb1b5a52","http://resolver.tudelft.nl/uuid:54e41f8c-4ba6-454d-9f87-6471cb1b5a52","Forward-Looking GPR Imaging with Near-Optimal 3-D Synthetic Array","Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Yarovoy, Alexander (TU Delft Microwave Sensing, Signals & Systems)","","2019","In this paper, we propose an Elevation-Radial scanned Synthetic Aperture Radar (E-RadSAR) for forward-looking ground penetrating radar (GPR) imaging. The E-RadSAR exploits the advantages of both RadSAR and Elevation-Circular SAR (E-CSAR) by utilizing the SAR technique in the cross- and down-range directions for signal acquisition. It could be implemented with fewer antennas compared to the RadSAR but provides higher spatial resolutions than that of E-CSAR. These features make it very attractive for space-and/or cost-constrained imaging applications, for instance, the GPR systems used for tunnel boring machines (TBM). However, the E-RadSAR synthesizes a three-dimensional (3-D) array by taking measurements in a volume, which makes the traditional sampling criterion no longer applicable for its sampling strategy design. To tackle 3-D (synthetic) array sampling/design, we formulate it as a sensor selection problem and suggest an efficient selection algorithm, i.e., modified clustered FrameSense (modified CFS). Then it is used for 3-D array sampling design. The imaging performances of the resultant near-optimal 3-D arrays are demonstrated through numerical simulations.","Forward-looking imaging; Ground penetrating radar; Sampling design; Three-dimensional (3-D) synthetic array","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","","","","Microwave Sensing, Signals & Systems","","",""
"uuid:0913c6df-9f01-42a5-add2-302ff0f2b156","http://resolver.tudelft.nl/uuid:0913c6df-9f01-42a5-add2-302ff0f2b156","Highly efficient absorption heat pump and refrigeration systems based on ionic liquids: Fundamentals & Applications","Wang, M. (TU Delft Engineering Thermodynamics)","Infante Ferreira, C.A. (promotor); Vlugt, T.J.H. (promotor); Delft University of Technology (degree granting institution)","2019","Improving efficiencies of thermal energy conversion systems is an important way to slow down global warming and mitigate climate change. Vapor absorption heat pump and refrigeration cycles are highly efficient ways of heating and cooling. These thermally activated systems also provide opportunities for the integration with a wide spectrum of low-grade and renewable heat sources, such as district heating networks, exhaust industrial heat, concentrated solar thermal energy and biomass. New fluids - ionic liquids - have been introduced into the absorption refrigeration/ heat pump field as absorbents to overcome drawbacks of traditional working fluids and to improve the energetic efficiency of systems. Some ionic liquids show high boiling points, superior thermal and chemical stabilities and strong affinities with refrigerants. Ammonia (NH3) is an environmentally friendly refrigerant with favorable thermodynamic and transport performance. Thus, studies in this thesis placed emphasis on the ammonia/ionic liquids working pairs. Studies in this thesis focus on exploring applications of ammonia/ionic liquid based vapor absorption refrigeration cycles, from a practical point of view in the refrigeration and heat pump field. By applying multi-scale evaluations covering thermodynamic and heat and mass transport aspects, it is intended to further understand the fundamentals of applying ionic liquids in heating and cooling systems. The highlights include: Assessments of equilibriummodels applied for ammonia-ionic liquid working fluids; Prediction of properties of ammoniaionic liquid fluids using molecular simulation; Collection and modeling of relevant thermophysical properties; Evaluation of the heat and mass transfer performance. Besides, concepts of using ionic liquids as absorbents with ammonia as the refrigerant in various thermodynamic cycles are analyzed and evaluated for applications in the built environment and industry...","Absorption cycle; ionic liquid; Ammonia; refrigeration; Heat pump; Plate heat exchanger","en","doctoral thesis","","978-94-6366-134-8","","","","","","","","","Engineering Thermodynamics","","",""
"uuid:132acaed-13ad-480a-8b3c-5f56c692bb6d","http://resolver.tudelft.nl/uuid:132acaed-13ad-480a-8b3c-5f56c692bb6d","Multi-train trajectory optimization for energy-efficient timetabling","Wang, P. (TU Delft Transport and Planning); Goverde, R.M.P. (TU Delft Transport and Planning)","","2019","This paper proposes a novel approach for energy-efficient timetabling by adjusting the running time allocation of given timetables using train trajectory optimization. The approach first converts the arrival and departure times to time window constraints in order to relax the given timetable. Then a train trajectory optimization method is developed to find optimal arrival/departure times and optimal energy-efficient speed profiles within the relaxed time windows. The proposed train trajectory optimization method includes two types, a single-train trajectory optimization (STTO), which focuses on optimizing individual train movements within the relaxed arrival and departure time windows, and a multi-train trajectory optimization (MTTO), which computes multi-train trajectories simultaneously with a shared objective of minimizing multi-train energy consumption and an additional target of eliminating conflicts between trains. The STTO and MTTO are re-formulated as a multiple-phase optimal control problem, which has the advantage of accurately incorporating varying gradients, curves and speed limits and different train routes. The multiple-phase optimal control problem is then solved by a pseudospectral method. The proposed approach is applied in case studies to fine-tune two timetables, for a single-track railway corridor and a double-track corridor of the Dutch railway. The results suggest that the proposed approach is able to improve the energy efficiency of a timetable.","Energy efficient timetabling; Pseudospectral method; Train trajectory optimization; Transportation","en","journal article","","","","","","","","2020-09-19","","","Transport and Planning","","",""
"uuid:915f33c8-ecc2-4b50-8ab1-c820d8d138f5","http://resolver.tudelft.nl/uuid:915f33c8-ecc2-4b50-8ab1-c820d8d138f5","Progradation Speed of Tide-Dominated Tidal Flats Decreases Stronger Than LinearlyWith Decreasing Sediment Availability and LinearlyWith Sea Level Rise","Maan, D.C. (TU Delft Coastal Engineering); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Wang, Zhengbing (TU Delft Coastal Engineering)","","2019","We use the results of a one-dimensional morphodynamic model and the basis of the “Lagrangian equilibrium state” (Maan et al., 2015, https://doi.org/10.1002/2014JF003311) to derive a quantitative relationship between the progradation speed of tidal flats and the suspended sediment concentration in their adjacent waters and show that the speed increases more than linearly with the concentration. We also show that horizontally prograding flats rise vertically with sea level rise at the expense of their horizontal speed via a linear relationship. If accretion rates are insufficient to keep up with sea level rise, however, the intertidal flat submerges and retreats landward at the same time. We apply the obtained relationships to the Yangtze Estuary to estimate the critical sediment concentration level below which a shift from progradation to retreat can be expected.","coastal retreat; intertidal flats; progradation speed; sea level rise; sediment availability; waves","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:179832e2-6e82-4e73-84f6-c5cbbf75ab03","http://resolver.tudelft.nl/uuid:179832e2-6e82-4e73-84f6-c5cbbf75ab03","Improved aerosol correction for OMI tropospheric NO2 retrieval over East Asia: Constraint from CALIOP aerosol vertical profile","Liu, Mengyao (Peking University; Royal Netherlands Meteorological Institute (KNMI)); Lin, Jintai (Peking University); Folkert Boersma, K. (Royal Netherlands Meteorological Institute (KNMI); Wageningen University & Research); Pinardi, Gaia (Royal Belgian Institute for Space Aeronomy (BIRA-IASB)); Wang, Yang (Max Planck Institute of Chemistry); Chimot, J.J. (TU Delft Atmospheric Remote Sensing); Wagner, Thomas (Max Planck Institute of Chemistry); Xie, Pinhua (Chinese Academy of Sciences; University of Science and Technology of China); Eskes, Henk (Royal Netherlands Meteorological Institute (KNMI))","","2019","Satellite retrieval of vertical column densities (VCDs) of tropospheric nitrogen dioxide (NO2) is critical for NOx pollution and impact evaluation. For regions with high aerosol loadings, the retrieval accuracy is greatly affected by whether aerosol optical effects are treated implicitly (as additional effective clouds) or explicitly, among other factors. Our previous POMINO algorithm explicitly accounts for aerosol effects to improve the retrieval, especially in polluted situations over China, by using aerosol information from GEOS-Chem simulations with further monthly constraints by MODIS/Aqua aerosol optical depth (AOD) data. Here we present a major algorithm update, POMINO v1.1, by constructing a monthly climatological dataset of aerosol extinction profiles, based on level 2 CALIOP/CALIPSO data over 2007-2015, to better constrain the modeled aerosol vertical profiles. We find that GEOS-Chem captures the month-to-month variation in CALIOP aerosol layer height (ALH) but with a systematic underestimate by about 300-600 m (season and location dependent), due to a too strong negative vertical gradient of extinction above 1 km. Correcting the model aerosol extinction profiles results in small changes in retrieved cloud fraction, increases in cloud-top pressure (within 2 %-6 % in most cases), and increases in tropospheric NO2 VCD by 4 %-16 % over China on a monthly basis in 2012. The improved NO2 VCDs (in POMINO v1.1) are more consistent with independent ground-based MAX-DOAS observations (R2=0.80, NMB =-3.4 %, for 162 pixels in 49 days) than POMINO (R2=0.80, NMB =-9.6 %), DOMINO v2 (R2=0.68, NMB =-2.1 %), and QA4ECV (R2=0.75, NMB =-22.0 %) are. Especially on haze days, R2 reaches 0.76 for POMINO v1.1, much higher than that for POMINO (0.68), DOMINO v2 (0.38), and QA4ECV (0.34). Furthermore, the increase in cloud pressure likely reveals a more realistic vertical relationship between cloud and aerosol layers, with aerosols situated above the clouds in certain months span id=page2 instead of always below the clouds. The POMINO v1.1 algorithm is a core step towards our next public release of the data product (POMINO v2), and it will also be applied to the recently launched S5P-TROPOMI sensor.","","en","journal article","","","","","","","","","","","Atmospheric Remote Sensing","","",""
"uuid:12bd3d46-9b6a-47ce-9e08-7709ec70c40a","http://resolver.tudelft.nl/uuid:12bd3d46-9b6a-47ce-9e08-7709ec70c40a","Guided Stochastic Optimization for Motion Planning","Magyar, Bence (Heriot-Watt University); Tsiogkas, Nikolaos (Heriot-Watt University; Katholieke Universiteit Leuven; Flanders Make); Ferreira de Brito, B.F. (TU Delft Learning & Autonomous Control; Fraunhofer IPA); Patel, Mayank (Fraunhofer IPA); Lane, David (Heriot-Watt University); Wang, Sen (Heriot-Watt University)","","2019","Learning from Demonstration (LfD) is a family of methods used to teach robots specific tasks. It is used to assist them with the increasing difficulty of performing manipulation tasks in a scalable manner. The state-of-the-art in collaborative robots allows for simple LfD approaches that can handle limited parameter changes of a task. These methods however typically approach the problem from a control perspective and therefore are tied to specific robot platforms. In contrast, this paper proposes a novel motion planning approach that combines the benefits of LfD approaches with generic motion planning that can provide robustness to the planning process as well as scaling task learning both in number of tasks and number of robot platforms. Specifically, it introduces Dynamical Movement Primitives (DMPs) based LfD as initial trajectories for the Stochastic Optimization for Motion Planning (STOMP) framework. This allows for successful task execution even when the task parameters and the environment change. Moreover, the proposed approach allows for skill transfer between robots. In this case a task is demonstrated to one robot via kinesthetic teaching and can be successfully executed by a different robot. The proposed approach, coined Guided Stochastic Optimization for Motion Planning (GSTOMP) is evaluated extensively using two different manipulator systems in simulation and in real conditions. Results show that GSTOMP improves task success compared to simple LfD approaches employed by the state-of-the-art collaborative robots. Moreover, it is shown that transferring skills is feasible and with good performance. Finally, the proposed approach is compared against a plethora of state-of-the-art motion planners. The results show that the motion planning performance is comparable or better than the state-of-the-art.","learning from demonstration; motion planning; robot learning; robot manipulation; trajectory optimization","en","journal article","","","","","","","","","","","Learning & Autonomous Control","","",""
"uuid:1bab7da8-0e46-4b39-beb1-2b4232895aa1","http://resolver.tudelft.nl/uuid:1bab7da8-0e46-4b39-beb1-2b4232895aa1","Comparison of three control structures for inducing higher-order sliding modes","Wang, Xuerui (TU Delft Control & Simulation; TU Delft Aerospace Structures & Computational Mechanics); van Kampen, E. (TU Delft Control & Simulation); Chu, Q. P. (TU Delft Control & Simulation)","","2019","For mitigating the chattering effect in the sliding mode control (SMC), many adaption mechanisms have been proposed to reduce the switching gains. However, less attention is paid to the control structure, which influences the resulting uncertainty term and determines the minimum possible gains. This paper compares three control structures for inducing higher-order sliding modes in finite time: nonlinear dynamic inversion (NDI) based SMC, higher-order sliding mode control (HOSMC) with artificially increased relative degree, and the recently proposed incremental nonlinear dynamic inversion (INDI) based SMC. The latter two control structures have reduced model dependency as compared to NDI-SMC. Moreover, their nominal control increments are found to be approximately equivalent if the sampling interval is sufficiently small and if their gains satisfy certain conditions. Under the same circumstances, the norm value of the resulting uncertainty using INDI-SMC is several orders of magnitude smaller than those using other control structures. For maintaining the sliding modes, the minimum possible gains required by HOSMC approximately equal those needed by INDI-SMC divided by the sampling interval. Nevertheless, these two approaches have comparable chattering degrees, which are effectively reduced as compared to NDI-SMC. The analytical results are verified by numerical simulations.","","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-05","","","Control & Simulation","","",""
"uuid:9c998486-a746-4e05-9acd-60ee75c05105","http://resolver.tudelft.nl/uuid:9c998486-a746-4e05-9acd-60ee75c05105","Entropy-Based Local Irregularity Detection for High-Speed Railway Catenaries With Frequent Inspections","Wang, H. (TU Delft Railway Engineering); Liu, Zhigang (Southwest Jiaotong University); Nunez, Alfredo (TU Delft Railway Engineering); Dollevoet, R.P.B.J. (TU Delft Railway Engineering)","","2019","The condition-based maintenance of high-speed railway catenary is an important task to ensure the continuous availability of train power supply. To improve the condition monitoring of catenary, this paper presents a novel scheme to detect catenary local irregularities using pantograph head acceleration measurements. First, a series of experimental inspections is carried out in a section of the Beijing-Guangzhou high-speed line in China. The time intervals between the inspections are shortened from the traditional six months to about 40 days, which enables monitoring the short-term degradation of local irregularities. Then, based on the wavelet packet entropy, an approach is proposed to detect local irregularities with different scales in length. Criteria for identifying and verifying the local irregularities are established based on the gradient and repeatability of entropy from multiple measurements. Results from the experimental inspections show that different scales of local irregularities can be detected by the proposed scheme. By using frequent inspections, local irregularities can be effectively verified after about seven inspections. The spatial distribution of local irregularities is found to be closely related to the catenary structure. These findings provide valuable information to deploy the scheme for a railway network.","Catenary condition monitoring; high-speed railway; inspection interval; local irregularity; wavelet packet entropy.","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-06-04","","","Railway Engineering","","",""
"uuid:726d850b-81a7-4e16-a9d1-0ff79f317198","http://resolver.tudelft.nl/uuid:726d850b-81a7-4e16-a9d1-0ff79f317198","Benefits and risks of truck platooning on freeway operations near entrance ramp","Wang, M. (TU Delft Transport and Planning); van Maarseveen, Sander (Student TU Delft); Happee, R. (TU Delft Intelligent Vehicles); Tool, Onno (Ministry of Infrastructure and the Environment); van Arem, B. (TU Delft Transport and Planning)","","2019","Truck platooning attracts considerable attention thanks to the promising fuel consumption benefits and business model. Nevertheless, concerns over the influence of long truck platoons on other traffic are raised by road operators. It is intriguing to understand under what conditions truck platooning will influence other traffic and what are the magnitudes of the influence. To this end, this paper reports a simulation study on examining the effects of truck platooning on freeway operations near an on-ramp. Systematic experiments were conducted with varying demand, market penetration rates (MPRs), intra-platooning gap, and platoon size. Moreover, three alternative strategies for truck platooning to accommodate merging traffic were tested: allowing courtesy lane change of trucks, active yielding, and keeping a larger intra-platoon gap than the acceptable gap for human drivers to change lane. Simulation results show that at high MPRs of truck platooning, the system mitigates congestion and increases throughput, at the expense of merging failures. The merge location distributions shift toward the end of the acceleration lane at congested flow and high MPRs. The effect on average merging speed is insignificant, but the merging speed in saturated traffic with truck platooning shows larger variability. At free flow and low MPRs, the influence is insignificant. Evaluation of the three alternatives concludes that the yielding strategy is most effective in resolving the merging problem with truck platooning. Courtesy lane change is not always possible because of the high speed difference between lanes and keeping a larger time gap suppresses the benefits in congestion mitigation and throughput increase.","","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:d9fbdf16-36be-4946-a372-9a7679a646c1","http://resolver.tudelft.nl/uuid:d9fbdf16-36be-4946-a372-9a7679a646c1","Optimal Platoon Trajectory Planning Approach at Arterials","Liu, M. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); Hoogendoorn, S.P. (TU Delft Transport and Planning)","","2019","Cooperative (automated) vehicles have the potential to enhance traffic efficiency and fuel economy on urban roads, especially at signalized intersections. An optimal control approach to optimize the trajectories of cooperative vehicles at fixed-timing signalized intersections along an arterial is presented. The proposed approach aims to optimize throughput first, and then to maximize comfort while minimizing travel delay and fuel consumption. The proposed approach is flexible in dealing with both quadratic and more complex cost functions. Assuming fixed timing signal control in a cycle and vehicle-to-infrastructure communication, the red phase is taken into account in position constraints for vehicles that cannot pass the intersection in the green phase. Safety is guaranteed by constraining the inter-vehicle distance larger than some desired value. The approach is scalable and can be used for joint trajectory planning of one platoon approaching another stationary platoon. It can also be extended to multiple intersections with fixed signal plans. To verify the performances of the controlled platoon, simulation under three different traffic scenarios is conducted, namely: an isolated intersection with/without downstream vehicle queues, and platoon control at multiple intersections. Three baseline scenarios without control are also designed to compare performances in relation to both mobility and fuel consumption in each controlled scenario. The results demonstrate that the controlled vehicles generate plausible behavior under control objectives and constraints. Moreover, the consideration of downstream vehicle queues and the application at both an isolated signalized intersection and arterial corridors on urban roads verify the flexible characteristics of the control framework.","","en","journal article","","","","","","","","","","Transport and Planning","Transport and Planning","","",""
"uuid:4b5e8a18-fed4-4070-a78b-7d817a0d2781","http://resolver.tudelft.nl/uuid:4b5e8a18-fed4-4070-a78b-7d817a0d2781","Sand‐Mud Tidal Flat Morphodynamics Influenced by Alongshore Tidal Currents","Wang, Yunwei (Hohai University); Wang, Yaping (East China Normal University); Yu, Qian (Nanjing University); Du, Zhiyun (Nanjing University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); Gao, Shu (East China Normal University)","","2019","Tidal flats, where significant land‐ocean interactions take place, are often abstracted as a cross‐shore bed profile with sediment zonation from the lower sand flat to the upper mud flat. However, in addition to cross‐shore tidal currents, the impact of the alongshore components on cross‐shore sediment transport, morphological evolution, and sediment grain‐size change remains unclear. Here we investigated sand‐mud tidal flat morphodynamics in the absence of waves by combining approaches of field observations, numerical modeling, and analytical interpretations, based on the example of the tidal flat on the central Jiangsu coast, China. The results show that the morphodynamic processes are complicated by the interactions of cross‐shore and alongshore tidal currents, cross‐shore flat morphology, and sediment zonation. With amplified phase lags of the alongshore tidal level at the boundaries, alongshore currents become dominant over cross‐shore tidal currents on the lower flat, while the upper flat is always dominated by the cross‐shore currents. Therefore, bed profiles and mud content on the upper flat were independent of the alongshore tidal current magnitude, being convex‐up and consisting of mud. In contrast, the strong alongshore currents can erode mud on the lower flat and promote landward sand transport from the subtidal area to the lower flat, forming a sand flat. The maximum tidal bed shear stress is almost spatially uniform across the muddy area but pronouncedly elevated where the bed sediment coarsens on the lower flat. The contributions of the alongshore tidal currents and sand‐mud sorting processes should be appropriately addressed in similar coastal environments.","","en","journal article","","","","","","Accepted Author Manuscript","","","","","Coastal Engineering","","",""
"uuid:f393c27a-b0a1-4058-a0c8-4b7b4c94f988","http://resolver.tudelft.nl/uuid:f393c27a-b0a1-4058-a0c8-4b7b4c94f988","Platoon of SAE Level-2 Automated Vehicles on Public Roads: Setup, Traffic Interactions, and Stability","Knoop, V.L. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); Wilmink, Isabel (TNO); Hoedemaeker, D. Marika (TNO); Maaskant, Mark (Prodrive Advanced Driver Training); Van der Meer, Evert-Jeen (Aon Risk Solutions, Trade and Manufacturing)","","2019","An increasing amount of vehicles are equipped with driver assistance systems; many of the vehicles currently on the market can be optionally equipped with adaptive cruise control and lane centering systems. Using both systems at the same time brings the vehicle to SAE level-2 automation . This means a driver does not need to perform longitudinal and lateral operational driving, although the driver should be ready to intervene at any time. While this can provide comfort, the interaction between vehicles operated by these systems might cause some undesired effects. This becomes particularly relevant with increasing market penetration rates. This paper describes an experiment with seven SAE level-2 vehicles driven as a platoon on public roads for a trip of almost 500 km. The paper discusses how the experiment was organized and the equipment of the vehicles. It also discusses the interaction of the platoon in traffic, as well as, in basic terms, the interaction between the automated vehicles. The experiences can be useful for other studies setting up field tests. The conclusion from this platoon test is: intentionally creating platoons on public roads is difficult in busy traffic conditions. Moreover, interactions between the vehicles in the platoon show that the current SAE level-2 systems are not suitable for driving as platoons of more than typically three to four vehicles, because of instabilities in the car-following behavior.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-11-07","","","Transport and Planning","","",""
"uuid:156d1eb2-bb3b-4566-9b3d-6000dddbf548","http://resolver.tudelft.nl/uuid:156d1eb2-bb3b-4566-9b3d-6000dddbf548","CrossFill: Foam Structures with Graded Density for Continuous Material Extrusion","Kuipers, T. (TU Delft Materials and Manufacturing; Ultimaker); Wu, J. (TU Delft Materials and Manufacturing); Wang, C.C. (The Chinese University of Hong Kong)","","2019","The fabrication flexibility of 3D printing has sparked a lot of interest in designing structures with spatially graded material properties. In this paper, we propose a new type of density graded structure that is particularly designed for 3D printing systems based on filament extrusion. In order to ensure high-quality fabrication results, extrusion-based 3D printing requires not only that the structures are self-supporting, but also that extrusion toolpaths are continuous and free of self-overlap. The structure proposed in this paper, called CrossFill, complies with these requirements. In particular, CrossFill is a self-supporting foam structure, for which each layer is fabricated by a single, continuous and overlap-free path of material extrusion. Our method for generating CrossFill is based on a space-filling surface that employs spatially varying subdivision levels. Dithering of the subdivision levels is performed to accurately reproduce a prescribed density distribution. We demonstrate the effectiveness of CrossFill on a number of experimental tests and applications.","Space-filling surface; Graded density; Continuous material extrusion; Functionally graded material; Fused deposition modeling","en","journal article","","","","","","Accepted author manuscript","","2021-06-11","","","Materials and Manufacturing","","",""
"uuid:246d5484-7c3e-49dd-a169-efd43ac21642","http://resolver.tudelft.nl/uuid:246d5484-7c3e-49dd-a169-efd43ac21642","The use of solubility parameters and free energy theory for phase behaviour of polymer-modified bitumen: a review","Zhu, Jiqing (Swedish National Road and Transport Research Institute); Balieu, Romain (KTH Royal Institute of Technology); Wang, H. (TU Delft Pavement Engineering)","","2019","Advances related to the use of solubility parameters and free energy theory for the phase behaviour study of polymer-modified bitumen (PMB) are reviewed in this paper. The origin and effects of PMB phase behaviour are criticised with a focus on PMB storage stability, morphology and swelling ratio. An overview of the solubility approach for studying PMB is given regarding the historical and future developments. Free energy expressions for PMB systems are analysed, including the free energy of mixing, elastic free energy and gradient energy. The kinetic aspects are discussed with respect to the diffusion and flow processes. It is indicated that the solubility bodies in the three-dimensional Hansen space and their degree of intersection can be useful for analysing the PMB thermodynamic equilibrium and thus storage stability. But they give no indication by themselves on the PMB morphology. With solubility parameters linked to the PMB free energy, however, an integrated thermodynamic approach can assist in understanding both PMB storage stability and morphology comprehensively. Due to the chemical complexity of bitumen and certain modifiers, the solubility body centres and radiuses should be both considered for a proper expression of the polymer-bitumen interaction in PMB. A hypothetical dilution process can simplify this process, but with limitations. The introduction of elastic free energy may lead to a new and more realistic expression of free energy for PMB system. With this overview, it is expected that a preliminary foundation is established towards a comprehensive and realistic thermodynamic framework for interpreting and predicting PMB phase behaviour.","free energy; phase behaviour; polymer-modified bitumen; solubility parameters; thermodynamics","en","review","","","","","","","","","","","Pavement Engineering","","",""
"uuid:15af4b3c-10cc-4c76-9836-983554c202ff","http://resolver.tudelft.nl/uuid:15af4b3c-10cc-4c76-9836-983554c202ff","A multi-state train-following model for the analysis of Virtual Coupling railway operations","Quaglietta, E. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); Goverde, R.M.P. (TU Delft Transport and Planning)","Peterson, Anders (editor); Joborn, Martin (editor); Bohlin, Markus (editor)","2019","The increasing need for capacity has led the railway industry to explore next generation signalling concepts such as Virtual Coupling which takes moving-block operations further by separating trains by a relative braking distance, like cars on the road. By means of a Vehicle-to-Vehicle (V2V) communication architecture trains can move in a virtually coupled platoon which can be treated as a single convoy at junctions, to improve capacity. This concept however introduces the need for additional safety constraints, especially at diverging junctions, which could make actual capacity improvements insufficient to justify investments. Hence, there is a need to understand capacity performances of Virtual Coupling and potential gains over state-of-practice signalling systems. This paper addresses this need by developing an innovative train-following model that captures operational states and corresponding transitions of trains running under Virtual Coupling. A comparative capacity analysis has been conducted for a portion of the South West Main Line in the UK. Promising results have been obtained, showing that the biggest capacity gains returned by Virtual Coupling relate to operational scenarios normally found in practice with trains having service stops and using different routes.","Virtual Coupling; train-following model; train separation; railway capacity","en","conference paper","","","","","","Accepted Author Manuscript","","2020-07-16","","","Transport and Planning","","",""
"uuid:1df54921-b164-4d4d-a796-cd1c910049ea","http://resolver.tudelft.nl/uuid:1df54921-b164-4d4d-a796-cd1c910049ea","Fully convolutional networks for street furniture identification in panorama images","Ao, Y. (University of Twente); Wang, J. (TU Delft Optical and Laser Remote Sensing); Zhou, M. (Chinese Academy of Sciences); Lindenbergh, R.C. (TU Delft Optical and Laser Remote Sensing); Yang, M. Y. (University of Twente)","","2019","Panoramic images are widely used in many scenes, especially in virtual reality and street view capture. However, they are new for street furniture identification which is usually based on mobile laser scanning point cloud data or conventional 2D images. This study proposes to perform semantic segmentation on panoramic images and transformed images to separate light poles and traffic signs from background implemented by pre-trained Fully Convolutional Networks (FCN). FCN is the most important model for deep learning applied on semantic segmentation for its end to end training process and pixel-wise prediction. In this study, we use FCN-8s model that pre-trained on cityscape dataset and finetune it by our own data. The results show that in both pre-trained model and fine-tuning, transformed images have better prediction results than panoramic images.","Fully Convolutional Networks; Object Identification; Panoramic Images; Semantic Segmentation; Street Furniture","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:e9289d5c-490d-4b67-8543-b831ebb230b7","http://resolver.tudelft.nl/uuid:e9289d5c-490d-4b67-8543-b831ebb230b7","Landscape Approach South-Florida: Landscape architecture explorations in Miami, Biscayne National Park, Lake Okeechobee & Everglades City through seven MSc-graduation projects","Huang, Cai (Student TU Delft); Wang, Yilin (Student TU Delft); Zhang, Xudong; Seminario Thulin, Andres (Student TU Delft); van Driel, Iris (Student TU Delft); Liu, Danyan (Student TU Delft); Droge, Jean Pierre (Student TU Delft)","Nijhuis, S. (editor)","2019","The coastal landscape of South Florida faces many challenges connected to climate change and urbanization. Sea level rise, loss of ecosystems, land subsidence, aquifer depletion are some of the issues that need serious attention. Landscape Approach Florida is showcasing results of a Landscape Architecture Design Lab where seven MSc-graduates explored the possibilities of landscape-based approaches to address the challenges from an integral and multi-scale spatial design perspective. Students employed landscape-based systemic strategies and design interventions that facilitate the ecological restoration of wetlands, provide flood protection, and increase urban resilience through green-blue infrastructures.","Landscape architecture; Flowscapes; Miami; research-by-design; Graduation studio; Florida; Adaptive design; Resilience and robustness; Landscape-based approach","en","report","TU Deflt","","","","","","","","","","Landscape Architecture","","",""
"uuid:388be3a7-9c12-444f-bcc4-220bdcce1ad7","http://resolver.tudelft.nl/uuid:388be3a7-9c12-444f-bcc4-220bdcce1ad7","A Morphodynamic Modeling Study on the Formation of the Large‐Scale Radial Sand Ridges in the Southern Yellow Sea","Tao, Jianfeng (Hohai University; Student TU Delft); Wang, Zhengbing (TU Delft Coastal Engineering; Hohai University; Deltares); Zhou, Zeng (Hohai University; The University of Auckland); Xu, Fan (Hohai University; The University of Auckland; East China Normal University); Zhang, Changkuan (Hohai University); Stive, M.J.F. (TU Delft Coastal Engineering)","","2019","The radial sand ridges (denoted as “RSRs” hereafter) in the Southern Yellow Sea, China, are morphologically striking because of the remarkable size and radial planar orientation, standing out as a unique coastal geomorphology among the worldwide sand ridge systems. The formation of this giant fan‐shaped geomorphic feature requires delicate conditions and awaits in‐depth investigation. Using an idealized morphodynamic model, this study unravels the governing factors for the formation of the unique large‐scale RSRs, in comparison with other types of sand ridge systems over the world. The effects of the M2 tidal constituent, the Coriolisforcing, the bed resistance, and the initial water depths on the morphodynamic behavior of the RSRs are explored. Numerical results indicate that the tidal regime, characterized by rotational and progressive current action associated with the tidal bulge, is dependent on the eastern coastline of China as well as latitudinal effects. Through the comparison between the simulated and the measured morphology, this tidal regime is demonstrated to be the key driverin forming and maintaining the present‐day RSRs. The runs with different parameters further suggest that the asymmetric pattern of the RSRs, which shows larger northern sand ridges than the southern ones, results from both the asymmetric distribution of current activity caused by the tidal bulge and unequal sediment supply. Overall, this study highlights the delicate condition, predominantly represented by the particular currents set up by the tidal wave system and the sediment supply, required to shape the striking large‐scale RSRs in the Southern Yellow Sea.","Jiangsu Coast; morphodynamic modeling; radial sand ridges; Southern Yellow Sea; tidal wave systems","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-01-05","","","Coastal Engineering","","",""
"uuid:954a05de-b6af-4fab-bd2c-239e9cddd757","http://resolver.tudelft.nl/uuid:954a05de-b6af-4fab-bd2c-239e9cddd757","Decadal morphological evolution of the mouth zone of the Yangtze Estuary in response to human interventions","Zhu, C. (TU Delft Coastal Engineering; East China Normal University); Guo, Leicheng (East China Normal University); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Deltares); Tian, Bo (East China Normal University); Wang, Xianye (East China Normal University); He, Qing (East China Normal Univeristy); Wang, Zhengbing (TU Delft Coastal Engineering; East China Normal University; Deltares)","","2019","The morphology of the Yangtze Estuary has changed substantially at decadal time scales in response to natural processes, local human interference and reduced sediment supply. Due to its high sediment load, the morphodynamic response time of the estuary is short, providing a valuable semi-natural system to evaluate large-scale estuarine morphodynamic responses to interference. Previous studies primarily addressed local morphologic changes within the estuary, but since an overall sediment balance is missing, it remains unclear whether the estuary as a whole has shifted from sedimentation to erosion in response to reduced riverine sediment supply (e.g. resulting from construction of the Three Gorges Dam). In this paper we examine the morphological changes of two large shoals in the mouth zone (i.e. the Hengsha flat and the Jiuduan shoal) using bathymetric data collected between 1953 and 2016 and a series of satellite images. We observe that the two shoals accreted at different rates before 2010 but reverted to erosion thereafter. Human activities such as dredging and dumping contribute to erosion, masking the impacts of sediment source reduction. The effects of local human intervention (such as the construction of a navigation channel) are instantaneous and are likely to have already resulted in new dynamic equilibrium conditions. The morphodynamic response time of the mouth zone to riverine sediment decrease is further suggested to be >30 years (starting from the mid-1980s). Accounting for the different adaptation time scales of various human activities is essential when interpreting morphodynamic changes in large-scale estuaries and deltas.","channel–shoal system; human activities; morphology; response time; Yangtze Estuary","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-11-06","","","Coastal Engineering","","",""
"uuid:a48fe424-7be2-41e0-8a71-6ed0e2874610","http://resolver.tudelft.nl/uuid:a48fe424-7be2-41e0-8a71-6ed0e2874610","Amplification and deformation of tidal wave in the Upper Scheldt Estuary","Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); Vandenbruwaene, Wouter (Waterbouwkundig Laboratorium, Antwerpen); Taal, Marcel (Deltares); Winterwerp, J.C. (TU Delft Environmental Fluid Mechanics; Deltares)","","2019","The records ofHWand LWin the most upper part of the Scheldt Estuary since 1971 have been analysed together with the daily river discharge. The tidal range, the hydraulic head and the ratio between the rising tide period to falling tide period have been determined for investigating the tidal amplification, the water surface slope along the river and the tidal asymmetry. The purpose of the investigation is to find out if a regime shift to high turbidity and strong tidal amplification is developing in the system. The results of the analysis show that both the hydraulic head and the tidal amplification have increased over time. The tide in this part of the estuary is flood-dominant, but the flood-dominancy is decreasing in time. These developments of the tide can be plausibly explained by a decrease of the river width followed by gradual deepening in the river. The most upper part of the Scheldt Estuary still behaves normally as a not too muddy system. No decisive answer can be given whether or not a regime shift towards a high-turbid system with strong tidal amplification may develop. How the system will develop depends on the change in capacity of pumping mud towards the upper reaches of the estuary. The increasing tidal amplitude can enhance this capacity although the flood-dominance itself is decreasing. Further study is recommended to better specify the potential danger of a regime shift to high-turbid system.","Hydraulic drag; Scheldt Estuary; Tidal amplification; Tidal asymmetry","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:5494c17c-f28f-409d-b402-b6962ff6fb45","http://resolver.tudelft.nl/uuid:5494c17c-f28f-409d-b402-b6962ff6fb45","Urbanization impact on Biotope in Shanghai: a comparative study between Huangpu District and Pujin Block","Song, Y. (TU Delft Environmental Technology and Design); Wang, Min (Tongji University)","","2019","Biotopes reveal a crucial role in the urban ecology, as they positively create habitat for the biodiversity development. With the increasing severe ecological challenge of urban high-density area and rising ecological awareness, people gradually realized the importance of biodiversity and began to explore the impact of urbanization on the biotope. This study in the city of Shanghai sets the framework for a study of the relation between spatial morphology and urban biotope, aims to discuss the impact of urbanization on the urban biotope. Two of high-density urban spaces and sub-urban spaces in the context of Shanghai area were examined as case studies, Huangpu District and Pujin Block, to demonstrate the biotope situations by disparate urbanization impact. In each study area, the urban biotope mapping methodology was developed base upon a general biotope classification method adapted to urban context. Main outputs are GIS based maps representing different biotopes, showing spatial difference in each area. Seven core biotope evaluation indicators of urban biodiversity were calculated: 1) area; 2) density; 3) shape index; 4) diversity index; 5) saturation index; 6) fragmentation index; 7) value index. Huangpu District and Pujin Block, although similar in size, exhibit distinct characteristics and perform different biotope situation by the impact of urbanization. This research aims to contribute to a better understanding and promotion of the relationship between biotope and urbanization, particularly for the disciplines involved in urban landscape planning, design and management.","biotope; urbanisation; Shanghai; Huangpu District; Pujin Block","en","poster","","","","","","","","","","","Environmental Technology and Design","","",""
"uuid:f8b5b23d-7099-4315-aee6-e7418e6f81c5","http://resolver.tudelft.nl/uuid:f8b5b23d-7099-4315-aee6-e7418e6f81c5","NUFFT-Based Range Migration for 3-D Imaging with Irregular Planar Array","Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Yarovoy, Alexander (TU Delft Microwave Sensing, Signals & Systems)","","2019","In this paper, a Nonuniform fast Fourier transform (NUFFT)-based range migration algorithm (RMA) is proposed for three-dimensional (3-D) imaging with irregular planar arrays. The proposed imaging algorithm takes advantage of NUFFT to reconstruct the signal spectra in the wavenumber domain, which overcomes the constraint of irregular spatial sampling on the utilization of Fourier-based imaging algorithms. Compared to the conventional coherent summation algorithms, i.e., backprojection and Kirchhoff migration, it is a very efficient method for 3-D image formation with nonuniform spatial sampling. To demonstrate its imaging performance, some numerical simulations are presented and discussed.","Nonuniform fast Fourier transform (NUFFT); Nonuniform spatial sampling; Planar array; Range migration; Three-dimensional(3-D) imaging","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","","","","Microwave Sensing, Signals & Systems","","",""
"uuid:a9a3f925-5a8b-4347-abd5-213e19ee5cfb","http://resolver.tudelft.nl/uuid:a9a3f925-5a8b-4347-abd5-213e19ee5cfb","Future Response of the Wadden Sea Tidal Basins to Relative Sea-Level rise—An Aggregated Modelling Approach","Lodder, Q.J. (TU Delft Coastal Engineering); Wang, Zhengbing (TU Delft Coastal Engineering); Elias, Edwin P.L.; van der Spek, A.J.F. (TU Delft Coastal Engineering); de Looff, Harry (Rijkswaterstaat - WVL); Townend, Ian (University of Southampton)","","2019","Climate change, and especially the associated acceleration of sea-level rise, forms a serious threat to the Wadden Sea. The Wadden Sea contains the world’s largest coherent intertidal flat area and it is known that these flats can drown when the rate of sea-level rise exceeds a critical limit. As a result, the intertidal flats would then be permanently inundated, seriously affecting the ecological functioning of the system. The determination of this critical limit and the modelling of the transient process of how a tidal basin responds to accelerated sea-level rise is of critical importance. In this contribution we revisit the modelling of the response of the Wadden Sea tidal basins to sea-level rise using a basin scale morphological model (aggregated scale morphological interaction between tidal basin and adjacent coast, ASMITA). Analysis using this aggregated scale model shows that the critical rate of sea-level rise is not merely influenced by the morphological equilibrium and the morphological time scale, but also depends on the grain size distribution of sediment in the tidal inlet system. As sea-level rises, there is a lag in the morphological response, which means that the basin will be deeper than the systems morphological equilibrium. However, so long as the rate of sea-level rise is constant and below a critical limit, this offset becomes constant and a dynamic equilibrium is established. This equilibrium deviation as well as the time needed to achieve the dynamic equilibrium increase non-linearly with increasing rates of sea-level rise. As a result, the response of a tidal basin to relatively fast sea-level rise is similar, no matter if the sea-level rise rate is just below, equal or above the critical limit. A tidal basin will experience a long process of ‘drowning’ when sea-level rise rate exceeds about 80% of the critical limit. The insights from the present study can be used to improve morphodynamic modelling of tidal basin response to accelerating sea-level rise and are useful for sustainable management of tidal inlet systems.","Aggregated modelling; Intertidal flat; Sea-level rise; Wadden Sea","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:343b9965-e8e8-46c3-95e4-f0b4930e8ce9","http://resolver.tudelft.nl/uuid:343b9965-e8e8-46c3-95e4-f0b4930e8ce9","Residents' willingness to participate in green infrastructure: Spatial differences and influence factors in Shanghai, China","Yu, Yang (Shanghai Normal University); Xu, Hui (Shanghai Normal University); Wang, Xiaohan (Shanghai Normal University); Wen, Jiahong (Shanghai Normal University); Du, Shiqiang (Shanghai Normal University); Zhang, Min (Shanghai Normal University; Shanghai Estuarine and Coastal Science Research Center); Ke, Q. (TU Delft Hydraulic Structures and Flood Risk)","","2019","Green infrastructure (GI) plays a fundamental role in achieving urban pluvial flood management, mitigating urban heat island effect, and improving living suitability. Residents' participation is the main driving force of GI implementation. Based on semi-structured interviews, GIS spatial analysis, and multiple regression, we investigated residents' willingness to participate in the implementation of GI in public and private space and identified the influence factors in Shanghai, China. The results show that, compared with private space, residents prefer to implement GI in public space, where they have different preferences of GI measures. On urban scale, residents' willingness to participate in the implementation of GI in private space is characterized as ""high in the inner city, low in the suburban areas"", while the spatial difference is insignificant for public space. In addition, the factors affecting residents' willingness to participate in the implementation of GI are different in private and public space. The deterministic factors of GI participation are gender, education level, and floor for private space, while only include building age for public space, in addition to the common factors of free time, cognition of GI, perception of pluvial flood risk, supportive factors, and environment-improving factors that can influence both private and public space GI participation. Our analysis therefore provides valuable information for policymakers concerning nature-based solutions to climate change adaptation and urban sustainability.","Green infrastructure; Influence factor; Residents' willingness; Shanghai; Spatial difference","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:99827774-7669-47aa-8f38-d57156c4dddc","http://resolver.tudelft.nl/uuid:99827774-7669-47aa-8f38-d57156c4dddc","Study of Lateral Flow in a Stratified Tidal Channel-Shoal System: The Importance of Intratidal Salinity Variation","Zhou, Z. (TU Delft Coastal Engineering; East China Normal University); Ge, Jianzhong (East China Normal University; Institute of Eco-Chongming (IEC)); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Deltares); Ma, Jianfei (East China Normal Univeristy); Ding, Ping Xing (East China Normal Univeristy)","","2019","Lateral flow significantly contributes to the near-bottom mass transport of salinity in a channel-shoal system. In this study, an integrated tripod system was deployed in the transition zone of a channel-shoal system of the Changjiang Estuary (CE), China, to observe the near-bottom physics with high temporal/spatial resolution, particularly focusing on the lateral-flow-induced mass transport. These in situ observations revealed a small-scale salinity fluctuation around low water slack during moderate and spring tidal conditions. A simultaneous strong lateral current was also observed, which was responsible for this small-scale fluctuation. A high-resolution unstructured-grid Finite-Volume Community Ocean Model has been applied for the CE to better understand the mechanism of this lateral flow and its impact on salinity transport. The model results indicate that a significant southward near-bed shoal-to-channel current is generated by the salinity-driven baroclinic pressure gradient. This lateral current affects the salinity transport pattern and the residual current in the cross-channel direction. Cross-channel residual current shows a two-layer structure in the vertical, especially in the intermediate tide when the lateral flow notably occurred. Both observation and model results indicate that near-bottom residual transport of water moved consistently southward (shoal to channel). Mechanisms for this intratidal salinity variation and its implications can be extended to other estuaries with similar channel-shoal features.","channel-shoal system; lateral flow; momentum balance; salinity","en","journal article","","","","","","Accepted Author Manuscript","","2020-02-29","","","Coastal Engineering","","",""
"uuid:61c21b75-bda0-460a-b185-dac7459020f4","http://resolver.tudelft.nl/uuid:61c21b75-bda0-460a-b185-dac7459020f4","Quadrotor Fault Tolerant Incremental Sliding Mode Control driven by Sliding Mode Disturbance Observers","Wang, Xuerui (TU Delft Control & Simulation); Sun, S. (TU Delft Control & Simulation); van Kampen, E. (TU Delft Control & Simulation); Chu, Q. P. (TU Delft Control & Simulation)","","2019","This paper proposes an Incremental Sliding Mode Control driven by Sliding Mode Disturbance Observers (INDI-SMC/SMDO), with application to a quadrotor fault tolerant control problem. By designing the SMC/SMDO based on the control structure of the sensor-based Incremental Nonlinear Dynamic Inversion (INDI), instead of the model-based Nonlinear Dynamic Inversion (NDI) in the literature, the model dependency of the controller and the uncertainties in the closed-loop system are simultaneously reduced. This allows INDI-SMC/SMDO to passively resist a wider variety of faults and external disturbances using continuous control inputs with lower control and observer gains. When applied to a quadrotor, both numerical simulations and real-world flight tests demonstrate that INDI based SMC/SMDO has better performance and robustness over NDI based SMC/SMDO, in the presence of model uncertainties, wind disturbances, and sudden actuator faults. Moreover, the implementation process is simplified because of the reduced model dependency and smaller uncertainty variations of INDI-SMC/SMDO. Therefore, the proposed control method can be easily implemented to improve the performance and survivability of quadrotors in real life.","Fault-Tolerant Control; Incremental Nonlinear Dynamic Inversion; Quadrotor flight tests; Sliding Mode Control; Sliding Mode Disturbance Observer","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-05","","","Control & Simulation","","",""
"uuid:c581ee72-a9e8-4a26-8bd0-c93f5178f61f","http://resolver.tudelft.nl/uuid:c581ee72-a9e8-4a26-8bd0-c93f5178f61f","Stability Analysis for Incremental Nonlinear Dynamic Inversion Control","Wang, Xuerui (TU Delft Control & Simulation); van Kampen, E. (TU Delft Control & Simulation); Chu, Q. P. (TU Delft Control & Simulation); Lu, Peng (The Hong Kong Polytechnic University)","","2019","As a sensor-based control method, incremental nonlinear dynamic inversion (INDI) has been applied to various aerospace systems and has shown desirable robust performance against aerodynamic model uncertainties. However, its previous derivation based on the time scale separation principle has some limitations. There is also a need for stability and robustness analysis for INDI. Therefore, this paper reformulates the INDI control law without using the time scale separation principle and generalizes it for systems with arbitrary relative degree, with consideration of the internal dynamics. The stability of the closed-loop system in the presence of external disturbances is analyzed using Lyapunov methods and nonlinear system perturbation theory. Moreover, the robustness of the closed-loop system against regular and singular perturbations is analyzed. Finally, this reformulated INDI control law is verified by a Monte Carlo simulation for an aircraft command tracking problem in the presence of external disturbances and model uncertainties.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-05","","","Control & Simulation","","",""
"uuid:4d0a0dbc-6388-4671-bb5f-447ab281bd25","http://resolver.tudelft.nl/uuid:4d0a0dbc-6388-4671-bb5f-447ab281bd25","Single-Epoch, Single-Frequency Multi-GNSS L5 RTK under High-Elevation Masking","Wang, Kan (Curtin University); Chen, Pei (Beihang University); Teunissen, P.J.G. (TU Delft Mathematical Geodesy and Positioning; TU Delft Geoscience and Remote Sensing; Curtin University)","","2019","The Japanese Quasi-Zenith Satellite System (QZSS) satellite system has placed in orbit four satellites by October 2017. The Indian Regional Navigation Satellite System (IRNSS) system has launched the new satellite IRNNSS-11 in April 2018, completing seven operational satellites. Together with the GPS block IIF satellites and the Galileo satellites, four different global navigation satellite systems (GNSSs) are providing precise L5 signals on the frequency of 1176.45 MHz. In this contribution, we challenge the strength of the multi-GNSS model by analysing its single-frequency (L5), single-epoch (instantaneous) precise positioning capabilities under high-elevation masking (up to 40 degrees). With more satellites available, multi-GNSS real time kinematic (RTK) positioning is possible using L5-only signals with a high customary elevation mask. This helps to enable positioning in areas with constrained measurement geometry, and could significantly reduce the multipath effects in difficult measurement environments like urban canyons and mountainous areas. In this study, benefiting from the location of the Asia⁻Australia area, instantaneous multi-GNSS L5 RTK analysis is performed with respect to the ambiguity resolution and positioning performance. Formal results are shown and discussed for baselines located in different grids covering Australia, part of the Pacific Ocean, Indian Ocean and Asia, and empirical analysis is given for two baselines in Perth, Australia. Compared to the stand-alone cases, for baselines in Perth, it is shown that combining L5 signals from GPS/Galileo/QZSS/IRNSS significantly improves both the ambiguity success rates (ASR) and the positioning performance under high elevation mask. While the average single-system ASR is under 50% even with a low elevation mask of 10 degrees, combining all the four systems increases the ASR to above 95% under an elevation cut-off angles of 40 degrees. With an elevation mask of 40 degrees, using satellites from one system does not allow for meaningful positioning solutions of more than 8 h within the test day, while mm-to-cm level ambiguity-fixed standard deviations could be obtained based on the positioning results of almost the entire day when combining all the four systems. In addition to that, simulation was also performed for receivers with larger signal standard deviations, i.e., for low-cost receivers or receivers located in environments with larger multipath.","High elevation masking; Instantaneous positioning; L5 frequency; Multi-GNSS; Single-epoch ambiguity resolution","en","journal article","","","","","","This article belongs to the section Remote Sensors","","","","Geoscience and Remote Sensing","Mathematical Geodesy and Positioning","","",""
"uuid:8ee914fb-be96-40cf-8d14-7c4b10dcfed6","http://resolver.tudelft.nl/uuid:8ee914fb-be96-40cf-8d14-7c4b10dcfed6","Sixty years of global progress in managed aquifer recharge","Dillon, P. (CSIRO Land and Water; Flinders University); Stuyfzand, Pieter Jan (TU Delft Geo-engineering; KWR Water Research Institute); Grischek, T. (Dresden University of Applied Sciences); Lluria, M. (Hydrosystems Inc.); Jain, R. C. (CGWB, New Delhi); Wang, W. (University Jinan, Jinan); Fernandez, E. (Tragsa); Zheng, Y. (Southern University of Science and Technology); Rossetto, R. (Scuola Superiore Sant’Anna)","","2019","The last 60 years has seen unprecedented groundwater extraction and overdraft as well as development of new technologies for water treatment that together drive the advance in intentional groundwater replenishment known as managed aquifer recharge (MAR). This paper is the first known attempt to quantify the volume of MAR at global scale, and to illustrate the advancement of all the major types of MAR and relate these to research and regulatory advancements. Faced with changing climate and rising intensity of climate extremes, MAR is an increasingly important water management strategy, alongside demand management, to maintain, enhance and secure stressed groundwater systems and to protect and improve water quality. During this time, scientific research—on hydraulic design of facilities, tracer studies, managing clogging, recovery efficiency and water quality changes in aquifers—has underpinned practical improvements in MAR and has had broader benefits in hydrogeology. Recharge wells have greatly accelerated recharge, particularly in urban areas and for mine water management. In recent years, research into governance, operating practices, reliability, economics, risk assessment and public acceptance of MAR has been undertaken. Since the 1960s, implementation of MAR has accelerated at a rate of 5%/year, but is not keeping pace with increasing groundwater extraction. Currently, MAR has reached an estimated 10 km3/year, ~2.4% of groundwater extraction in countries reporting MAR (or ~1.0% of global groundwater extraction). MAR is likely to exceed 10% of global extraction, based on experience where MAR is more advanced, to sustain quantity, reliability and quality of water supplies.","Artificial recharge; History of hydrogeology; Managed aquifer recharge; Review; Water banking","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:3f0434da-6d5d-4a5e-9da9-8cd53d114b96","http://resolver.tudelft.nl/uuid:3f0434da-6d5d-4a5e-9da9-8cd53d114b96","Cross-Comparison and Calibration of Two Microscopic Traffic Simulation Models for Complex Freeway Corridors with Dedicated Lanes","Kan, Xingan (University of California); Xiao, L. (TU Delft Transport and Planning); Liu, Hao (Institute of Transportation Studies); Wang, M. (TU Delft Transport and Planning); Schakel, W.J. (TU Delft Transport and Planning); Lu, Xiao-Yun (Institute of Transportation Studies); van Arem, B. (TU Delft Transport and Planning); Shladover, SE (Institute of Transportation Studies); Ferlis, Robert A. (Federal Highway Administration)","","2019","Realistic microscopic traffic simulation is essential for prospective evaluation of the potential impacts of new traffic control strategies. Freeway corridors with interacting bottlenecks and dedicated lanes generate complex traffic flow phenomena and congestion patterns, which are difficult to reproduce with existing microscopic simulation models. This paper discusses two alternative driving behavior models that are capable of modeling freeways with multiple bottlenecks and dedicated lanes over an extended period with varying demand levels. The models have been calibrated using archived data from a complicated 13-mile long section of the northbound SR99 freeway near Sacramento, California, for an 8-hour time period in which the traffic fluctuated from free-flow to congested conditions. The corridor includes multiple bottlenecks, multiple entry and exit ramps, and an HOV lane. Calibration results show extremely good agreement between field data and model predictions. The models have been cross-validated and produced similar macroscopic traffic performance. The main behavior that should be captured for successful modeling of such a complex corridor includes the anticipative and cooperative driver behavior near merges, lane preference in presence of dedicated lanes, and variations in desired headway along the corridor.","","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:2bfc63f4-52f4-4109-a501-14531d5445f5","http://resolver.tudelft.nl/uuid:2bfc63f4-52f4-4109-a501-14531d5445f5","Effect of tungsten based coating characteristics on microstructure and thermal conductivity of diamond/Cu composites prepared by pressueless infiltration","Jia, Jinhao (National University of Defense Technology); Bai, Shuxin (National University of Defense Technology); Xiong, Degan (National University of Defense Technology); Wang, Jie (Student TU Delft); Chang, J. (TU Delft ImPhys/Optics)","","2019","Tungsten coatings were deposited on diamond particles by vacuum magnetron sputtering. The coated diamond particles were firstly heat treated at different temperatures, and diamond/copper (Cu) composites were fabricated by using a pressureless infiltration method afterwards. The influences of heat treatment on the microstructure and composition of tungsten based coating surface and diamond/copper composites were analysed. Notable differences were found in the microstructure with heating temperatures. Moreover, the tungsten based coating surface contained large quantities of oxidised tungsten, and the phase composition of the coatings varied within the range of tungsten–W 2 C–WC as the heat treatment temperature increased. The fracture surface morphologies in the copper matrix composites reinforced with diamond particles with coatings were identically characterised with the presence of ductile fracture of matrix accompanied by dissociation of diamond particles from the matrix. The thermal conductivity (TC) and gas tightness behaviours of the diamond/copper composites were also explored. A maximum TC of 768 W m −1 K −1 and a fine gas tightness of 2.5 × 10-10 Pa m 3 /s were obtained with reinforcement of tungsten-coated diamond particles treated at 800 °C. The value of the interface thermal resistance between copper and diamond particles was also estimated and specifically discussed.","Diamond/Cu composites; Heat treatment; Thermal conductivity; Tungsten coating","en","journal article","","","","","","Accepted Author Manuscript","","2021-02-25","","","ImPhys/Optics","","",""
"uuid:f639b961-938a-4e4d-8569-0311d0e0f0aa","http://resolver.tudelft.nl/uuid:f639b961-938a-4e4d-8569-0311d0e0f0aa","Quadrotor fault-tolerant incremental nonsingular terminal sliding mode control","Wang, Xuerui (TU Delft Control & Simulation); van Kampen, E. (TU Delft Control & Simulation); Chu, Q. P. (TU Delft Control & Simulation)","","2019","This paper proposes incremental nonsingular terminal sliding mode control for a class of multi-input and multi-output nonlinear systems considering model uncertainties, external disturbances, and sudden actuator faults. This method is free from singularity because it does not involve any negative fractional power. The convergence time in both reaching and sliding phases are proved to be finite. Moreover, by fully exploiting sensor measurements, the proposed incremental control method simultaneously reduces model dependency and the uncertainty remaining in the closed-loop system. The reduction of model dependency simplifies the implementation process and reduces the computational load, while the reduction of uncertainty decreases the minimum possible sliding mode control gains, which is beneficial to chattering reduction. These merits are verified by a quadrotor trajectory tracking problem. Simulation results demonstrate that the proposed method has better robustness against model uncertainties, gusts, and actuator faults than the model-based nonsingular terminal sliding mode control in the literature.","Disturbance rejection; Fault-tolerant control; Nonsingular terminal sliding mode control; Quadrotor trajectory control; Sensor-based incremental control","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-05","","","Control & Simulation","","",""
"uuid:337dd7d3-a28d-44f2-be89-313f54aff797","http://resolver.tudelft.nl/uuid:337dd7d3-a28d-44f2-be89-313f54aff797","Adaptive joints with variable stiffness: Strategically arranged materials with transduction properties","Bier, H.H. (TU Delft Architectural Engineering); Wang, Qinyu (Eindhoven University of Technology); Teuffel, Patrick (Eindhoven University of Technology); Senatore, Gennaro (Swiss Federal Institute of Technology)","","2019","The environment around buildings keeps changing, while the static design solutions of buildings cannot perform well during the whole service life. In order to improve structural performances including strength (i.e. avoid collapse) and serviceability, adaptive structures are likely to establish as one of future trends in both research and application for the built environment. This project aims to synthesize a type of structural joints with variable stiffness capabilities. Stiffness variation is achieved by strategically arranged materials with transduction properties. Shape memory polymers (SMPs) feature large variation of stiffness between a glassy and a rubbery state, which makes them good candidates for application in shape control of adaptive structures. The structures will change themselves into optimal shapes corresponding to different load conditions. However, large shape changes require significant flexibility of the joints because their fixity can affect load-path and shape control. To address this problem, a variable stiffness joint is proposed. During shape/load-path control, the joint reduces its stiffness so that required deformation patterns can be achieved with low actuation energy. After shape control the joint recovers rigidity. Experimental studies showed the potential for application of joints with variable stiffness in adaptive structures.","Adaptive; Changes; Control; Joint; Load; Shape; Stiffness; Structures","en","journal article","","","","","","Energy Innovation #5: 4TU.BOUW Lighthouse projects + PDEng ISBN 978-94-6366-246-8","","","","","Architectural Engineering","","",""
"uuid:3f5524c6-ce5c-4875-8275-cb6307885dbb","http://resolver.tudelft.nl/uuid:3f5524c6-ce5c-4875-8275-cb6307885dbb","Vertical Forest Engineering: Applications of Vertical Forests with Self-Growing Connections in High-Rise Buildings","Wang, X. (TU Delft Bio-based Structures & Materials); Gard, W.F. (TU Delft Bio-based Structures & Materials); van de Kuilen, J.W.G. (TU Delft Bio-based Structures & Materials; Technische Universität München)","van de Kuilen, Jan-Willem (editor); Gard, Wolfgang (editor)","2019","Living architecture is thriving. The integration of buildings with vegetation has become a necessity in many metropolitan areas of the world today, including Singapore, New York City, Shanghai and Milan, to name a few. It expands the potential of vertical and horizontal, exterior and interior, exposed and enclosed spaces in a building that can be used to accommodate plants. Green infrastructures have benefits both on urban and building scales. They can be categorized into green roofs and vertical greenery systems that can be divided further into green façade, green/living wall, green terraces, elevated forests and vertical forests. There are many design and planting considerations for architects, structural engineers and botanists when using living architectures to mimic natural systems, such as climatic and regional considerations, primary functions and design objectives, structural support systems, maintenance, irrigation and so on. Plants used for vertical greenery are more likely to be hardwood species to adjust solar radiation during cooling and heating periods, and also for aesthetic pleasure. Take Bosco Verticale, which is located in Milan, as an example to look into engineering methods when trees grow on balconies of high rise buildings. It could be concluded that planting restraint safety system and regular maintenance are necessary for trees growing in the sky. But the change of growing conditions causes various problems such as stability and growth of trees. Instead of using steel cages and bracings to prevent falling off of trees in the sky, the concept of self-growing connections is proposed to provide the stability of vertical forests. This paper is meant to generate awareness of the possibilities of the integration of greenery vertically with buildings, show application considerations, and inspire future developments in typologies and integration with forests.","","en","conference paper","Delft University of Technology","","","","","","","","","","Bio-based Structures & Materials","","",""
"uuid:50f96286-9084-4c3e-b702-606bcdbc4e77","http://resolver.tudelft.nl/uuid:50f96286-9084-4c3e-b702-606bcdbc4e77","Observations Of Suspended Particle Size Distribution On An Energetic Ebb-Tidal Delta","Pearson, S.G. (TU Delft Coastal Engineering; Deltares); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); de Wit, F.P. (TU Delft Environmental Fluid Mechanics); Meijer-Holzhauer, H. (University of Twente; Deltares); de Looff, A.P. (Rijkswaterstaat); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2019","Sustainable management of barrier islands and tidal inlet systems requires a knowledge of sediment transport pathways throughout the system. This paper places in situ suspended sediment observations (obtained using a LISST) in context with seabed sediment samples and hydrodynamic measurements to identify such pathways. The results indicate two distinct populations of sediment in suspension on the ebb-tidal delta: locally resuspended fine sand and (largely flocculated) mud exported from the Wadden Sea on ebb tide. This reinforces the notion of the strong dependence of sediment pathways on particle size. Future work will combine additional lines of evidence to better distinguish suspended sand from sand-sized flocs and provide a more robust definition of these pathways.","","en","conference paper","World Scientific Publishing","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-12-01","","","Coastal Engineering","","",""
"uuid:62b1ac94-b8b2-4179-89d5-b78143f9de60","http://resolver.tudelft.nl/uuid:62b1ac94-b8b2-4179-89d5-b78143f9de60","Design, modelling and evaluation of a GaN based motor drive for a solar car","Wang, Lu (Student TU Delft); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Dong, J. (TU Delft DC systems, Energy conversion & Storage); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2019","In recent years, electrical vehicle (EV) starts showing its unique advantages that the conventional combustion vehicles do not have. Together with the increasing interests on EV, the motor drive with higher efficiency and lighter weight also becomes more attractive. A promising solution is to apply the wide band gap (WBG) components including gallium nitride (GaN) and silicon carbide (SiC) in the motor drive. Thus, the performance of the GaN, SiC and Si based motor drive in this application are compared. Besides, as the current maximum current rating of the GaN and SiC MOSFET is limited and insufficient to satisfy the large phase current in the acceleration and braking process, the inverter topology that adds the parallel MOSFETs in one position is considered. To reduce the time and cost for the development, this paper proposes the modelling of the motor drive, with which the voltage and current stress, power loss, thermal and electromagnetic performance can all be evaluated. The modelling to be introduced consists of the 1-D power loss, simplified thermal modelling of the motor drive and the 3-D modelling of the electromagnetic performance, detailed thermal performance of the motor drive. In the 3-D modelling, to make the heat transfer simulation closer to the realistic, computational fluid dynamic (CFD) is used to evaluated the heat transfer coefficient on the surface with forced air-cooling.","","en","conference paper","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-06-09","","","DC systems, Energy conversion & Storage","","",""
"uuid:cdbbad5b-0a26-4e3b-9988-3018ba6ed6d3","http://resolver.tudelft.nl/uuid:cdbbad5b-0a26-4e3b-9988-3018ba6ed6d3","Exploring the Performance of Different On-Demand Transit Services Provided by a Fleet of Shared Automated Vehicles: An Agent-Based Model","Wang, S. (TU Delft Mathematical Physics); Correia, Gonçalo (TU Delft Transport and Planning); Lin, H.X. (TU Delft Mathematical Physics)","","2019","Automated vehicles used as public transport show a great promise of revolutionizing current transportation systems. Still, there are many questions as to how these systems should be organized and operated in cities to bring the best out of future services. In this study, an agent-based model (ABM) is developed to simulate the on-demand operations of shared automated vehicles (SAVs) in a parallel transit service (PTS) and a tailored time-varying transit service (TVTS). The proposed TVTS system can switch service schemes between a door-to-door service (DDS) and a station-to-station service (SSS) according to what is best for the service providers and the travelers. In addition, the proposed PTS system that allows DDS and SSS to operate simultaneously is simulated. To test the conceptual design of the proposed SAV system, simulation experiments are performed in a hypothetical urban area to show the potential of different SAV schemes. Simulation results suggest that SAV systems together with dynamic ridesharing can significantly reduce average waiting time, the vehicle kilometres travelled and empty SAV trips. Moreover, the proposed optimal vehicle assignment algorithm can significantly reduce the empty vehicle kilometres travelled (VKT) for the pickups for all tested SAV systems up to about 40% and improve the system capacity for transporting the passengers. Comparing the TVTS system, which has inconvenient access in peak hours, with the PTS systems, which always makes available door-to-door transport, we conclude that the latter could achieve a similar system performance as the former in terms of average waiting time, service time and system capacity.","","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:d746dec7-c1d8-4ab8-94af-a9eaaed45c97","http://resolver.tudelft.nl/uuid:d746dec7-c1d8-4ab8-94af-a9eaaed45c97","Self-avoiding pruning random walk on signed network","Wang, H. (TU Delft Multimedia Computing); Qu, C. (TU Delft Multimedia Computing; Shandong University); Jiao, Chongze (Student TU Delft); Ruszel, W.M. (TU Delft Applied Probability)","","2019","A signed network represents how a set of nodes are connected by two logically contradictory types of links: positive and negative links. In a signed products network, two products can be complementary (purchased together) or substitutable (purchased instead of each other). Such contradictory types of links may play dramatically different roles in the spreading process of information, opinion, behaviour etc. In this work, we propose a self-avoiding pruning (SAP) random walk on a signed network to model e.g. a user's purchase activity on a signed products network. A SAP walk starts at a random node. At each step, the walker moves to a positive neighbour that is randomly selected, the previously visited node is removed and each of its negative neighbours are removed independently with a pruning probability r. We explored both analytically and numerically how signed network topological features influence the key performance of a SAP walk: the evolution of the pruned network resulted from the node removals, the length of a SAP walk and the visiting probability of each node. These findings in signed network models are further verified in two real-world signed networks. Our findings may inspire the design of recommender systems regarding how recommendations and competitions may influence consumers' purchases and products' popularity.","random walk; signed network; self-avoiding walk; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Multimedia Computing","","",""
"uuid:04cf8fe3-8d12-4925-94ea-2eb36f4776d0","http://resolver.tudelft.nl/uuid:04cf8fe3-8d12-4925-94ea-2eb36f4776d0","Bas-Relief Modeling from Normal Layers","Wei, Mingqiang (Nanjing University of Aeronautics and Astronautics); Tian, Yang (The Chinese University of Hong Kong; Chinese Academy of Sciences); Pang, Wai-Man (Caritas Institute of Higher Education); Wang, C.C. (TU Delft Materials and Manufacturing); Pang, Ming-Yong (Nanjing Normal University); Wang, Jun (Nanjing University of Aeronautics and Astronautics); Qin, Jin (The Hong Kong Polytechnic University); Heng, Pheng-Ann (The Chinese University of Hong Kong; Chinese Academy of Sciences)","","2019","Bas-relief is characterized by its unique presentation of intrinsic shape properties and/or detailed appearance using materials raised up in different degrees above a background. However, many bas-relief modeling methods could not manipulate scene details well. We propose a simple and effective solution for two kinds of bas-relief modeling (i.e., structure-preserving and detail-preserving), which is different from the prior tone mapping alike methods. Our idea originates from an observation on typical 3D models which are decomposed into a piecewise smooth base layer and a detail layer in normal field. Proper manipulation of the two layers contributes to both structure-preserving and detail-preserving bas-relief modeling. We solve the modeling problem in a discrete geometry processing setup that uses normal-based mesh processing as a theoretical foundation. Specifically, using the two-step mesh smoothing mechanism as a bridge, we transfer the bas-relief modeling problem into a discrete space, and solve it in a least-squares manner. Experiments and comparisons to other methods show that (i) geometry details are better preserved in the scenario with high compression ratios, and (ii) structures are clearly preserved without shape distortion and interference from details.","Bas-relief modeling; detail-preserving; discrete geometry processing; normal decomposition; structure-preserving","en","journal article","","","","","","Accepted author manuscript","","","","","Materials and Manufacturing","","",""
"uuid:dc18fedd-0b16-4d10-ab79-06f977756d02","http://resolver.tudelft.nl/uuid:dc18fedd-0b16-4d10-ab79-06f977756d02","MOHA: A Multi-Mode Hybrid Automaton Model for Learning Car-Following Behaviors","Lin, Q. (TU Delft Cyber Security); Zhang, Yihuan (Tongji University); Verwer, S.E. (TU Delft Cyber Security); Wang, Jun (Tongji University)","","2019","This paper proposes a novel hybrid model for learning discrete and continuous dynamics of car-following behaviors. Multiple modes representing driving patterns are identified by partitioning the model into groups of states. The model is visualizable and interpretable for car-following behavior recognition, traffic simulation, and human-like cruise control. The experimental results using the next generation simulation datasets demonstrate its superior fitting accuracy over conventional models.","car-following behavior; Computational modeling; Data mining; Data models; Hybrid automaton; Learning automata; Numerical models; simulation and control.; Time series analysis; Vehicles","en","journal article","","","","","","Accepted author manuscript","","","","","Cyber Security","","",""
"uuid:926c5022-2ac7-4b0d-9218-618b3ab89ea2","http://resolver.tudelft.nl/uuid:926c5022-2ac7-4b0d-9218-618b3ab89ea2","Sulfonamides removal under different redox conditions and microbial response to sulfonamides stress during riverbank filtration: A laboratory column study","Bai, Ying (Nanjing University); Ruan, Xiaohong (Nanjing University); Wang, F. (TU Delft Sanitary Engineering); Garnier, Antoine (The National Engineering School of Rennes); van der Hoek, J.P. (TU Delft Sanitary Engineering)","","2019","Riverbank filtration (RBF) as a barrier of pathogenic microorganisms and organic micropollutants recently has been proven capable of removing sulfonamides. However, the study about the effect of redox conditions on biodegradation of common and persistent sulfonamides in RBF is limited and the response of microbial communities to sulfonamides stress during RBF is unknown. In this study, two column set-ups (with residence time 5 days and 11 days respectively), simulating different redox conditions of riverbank filtration systems, were operated for seven months to investigate 1) the long-term effect of redox conditions on ng∙L−1 level sulfonamides (sulfapyridine, sulfadiazine, sulfamethoxazole, sulfamethazine, sulfaquinoxaline) removal, and 2) the microbial community evolution represented by the phylogenetic and metabolic function shift under non-lethal selective pressures of sulfonamides. The results showed that sulfonamides were more degradable under anoxic conditions than oxic and suboxic conditions. In the sulfonamides stressed community, the phylogenetic diversity increased slightly. Relative abundance of an intrinsic sulfonamides resistant bacteria Bacillus spp. increased, suggesting that sulfonamide resistance developed in specific bacteria under sulfonamides contamination pressure in RBF systems. At the same time, an activated transport function in the stressed microbial community was noticed. The predicted relative abundance of gene folP, which encodes dihydropteroate synthase, also increased significantly, indicating a detoxification mechanism and sulfonamides resistance potential under non-lethal selective pressures of sulfonamides in RBF systems.","Riverbank filtration; Sulfonamides; Redox condition; Microbial community structure; Metagenome prediction","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-06-26","","","Sanitary Engineering","","",""
"uuid:618a1d1f-2497-44d2-a574-8b415098835d","http://resolver.tudelft.nl/uuid:618a1d1f-2497-44d2-a574-8b415098835d","A Structure-Reconfigurable Series Resonant DC-DC Converter With Wide-Input and Configurable-Output Voltages","Shen, Yanfeng (Aalborg University); Wang, Huai (Aalborg University); Al Durra, Ahmed (Khalifa University of Science and Technology); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Blaabjerg, Frede (Aalborg University)","","2019","This paper proposes a new series resonant DC-DC converter with four configurable operation states depending on the input voltage and output voltage levels. It suits well for the DC-DC stage of grid-connected photovoltaic (PV) systems with a wide-input voltage range and different grid voltage levels, i.e., 110/120 V and 220/230/240 V. The proposed converter consists of a dual-bridge structure on the primary side and a configurable half- or full-bridge rectifier on the secondary side. The root-mean-square (RMS) currents are kept low over a fourfold voltage-gain range; The primary-side MOSFETs and secondary-side diodes can achieve zero-voltage switching (ZVS) on and zero-current switching (ZCS) off, respectively. Therefore, the converter can maintain high efficiencies over a wide voltage gain range. A fixed-frequency pulse width modulated (PWM) control scheme is applied to the proposed converter, which makes the gain characteristics independent of the magnetizing inductance and thereby simplifies the design optimization of the resonant tank. The converter topology and operation principle are first described. Then the characteristics, i.e., the dc voltage gain, soft-switching, and RMS currents, are detailed before a performance comparison with conventional resonant topologies is carried out. Furthermore, the design guidelines of the proposed converter are also presented. Finally, the experimental results from a 500-W converter prototype verify feasibility of the proposed converter.","configurable output voltage; DC-DC converter; DC-DC power converters; Inverters; reconfigurable structure; Rectifiers; Renewable energy sources; Resonant converters; series resonant converter; Topology; wide input voltage range; Zero voltage switching","en","journal article","","","","","","Accepted Author Manuscript","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:05c9fc08-c81f-4356-857e-48a27e7ec7f6","http://resolver.tudelft.nl/uuid:05c9fc08-c81f-4356-857e-48a27e7ec7f6","Effects of sintering pressure on the densification and mechanical properties of nanosilver double side sintered power module","Zhang, H. (TU Delft Electronic Components, Technology and Materials; Harbin University of Science and Technology); Liu, Y. (Harbin University of Science and Technology); Wang, Lingen (Boschman Technologies); Sun, Fenglian (Harbin University of Science and Technology); Fan, Jiajie (Hohai University); Placette, Mark D. (Iowa State University); Fan, Xuejun (Lamar University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2019","Modern power electronics has the increased demands in current density and high-temperature reliability. However, these performance factors are limited due to the die attach materials used to affix power dies microchips to electric circuitry. Although several die attach materials and methods exist, nanosilver sintering technology has received much attention in attaching power dies due to its superior high-temperature reliability. This paper investigated the sintering properties of nanosilver film in double-side sintered power packages. X-ray diffraction results revealed that the size of nanosilver particles increased after pressure-free sintering. Compared with the pressure-free sintered nanosilver particles, the 5-MPa sintered particles showed a higher density. When increasing sintering pressure from 5 to 30 MPa, the shear strength of the sintered package increased from 8.71 to 86.26 MPa. When sintering at pressures below 20 MPa, the fracture areas are mainly located between the sintered Ag layer and the surface metallization layer on the fast recovery diode (FRD) die. The fracture occurs through the FRD die and the metallization layer on the bottom molybdenum substrate when sintering at 30 MPa.","Fracture; nanosilver sintering; power electronics; shear strength","en","journal article","","","","","","Accepted author manuscript","","","","","Electronic Components, Technology and Materials","","",""
"uuid:645096af-a8b6-4e9a-a1b0-3646b13a3074","http://resolver.tudelft.nl/uuid:645096af-a8b6-4e9a-a1b0-3646b13a3074","Structural transition in interdependent networks with regular interconnections","Wang, X. (TU Delft Network Architectures and Services); Kooij, Robert (TU Delft Network Architectures and Services; Singapore University of Technology and Design); Moreno, Yamir (University of Zaragoza; ISI Foundation); Van Mieghem, P.F.A. (TU Delft Network Architectures and Services)","","2019","Networks are often made up of several layers that exhibit diverse degrees of interdependencies. An interdependent network consists of a set of graphs G that are interconnected through a weighted interconnection matrix B, where the weight of each intergraph link is a non-negative real number p. Various dynamical processes, such as synchronization, cascading failures in power grids, and diffusion processes, are described by the Laplacian matrix Q characterizing the whole system. For the case in which the multilayer graph is a multiplex, where the number of nodes in each layer is the same and the interconnection matrix B=pI, I being the identity matrix, it has been shown that there exists a structural transition at some critical coupling p∗. This transition is such that dynamical processes are separated into two regimes: if p>p∗, the network acts as a whole; whereas when p<p∗, the network operates as if the graphs encoding the layers were isolated. In this paper, we extend and generalize the structural transition threshold p∗ to a regular interconnection matrix B (constant row and column sum). Specifically, we provide upper and lower bounds for the transition threshold p∗ in interdependent networks with a regular interconnection matrix B and derive the exact transition threshold for special scenarios using the formalism of quotient graphs. Additionally, we discuss the physical meaning of the transition threshold p∗ in terms of the minimum cut and show, through a counterexample, that the structural transition does not always exist. Our results are one step forward on the characterization of more realistic multilayer networks and might be relevant for systems that deviate from the topological constraints imposed by multiplex networks.","","en","journal article","","","","","","","","","","","Network Architectures and Services","","",""
"uuid:85f5f3cf-a0ee-4fc5-bc53-3b616d8e2784","http://resolver.tudelft.nl/uuid:85f5f3cf-a0ee-4fc5-bc53-3b616d8e2784","Quantification of Tidal Asymmetry and Its Nonstationary Variations","Guo, Leicheng (Shanghai Estuarine and Coastal Science Research Center); Wang, Zhengbing (TU Delft Coastal Engineering); Townend, Ian (University of Southampton); He, Qing (Shanghai Estuarine and Coastal Science Research Center)","","2019","Tidal wave deformation and tidal asymmetry widely occur in tidal estuaries and lagoons. Tidal asymmetry has been intensively studied because of its controlling role on residual sediment transport and large‐scale morphological evolution. There are several methods available to characterize tidal asymmetry prompting the need for an overview of their applicability and shortcomings. In this work we provide a brief review and evaluation of two methods, namely, the harmonic method and the statistical method. The latter comprises several statistical measures that estimate the probability density function and various forms of skewness. We find that both the harmonic and statistical methods are effective and have complementary advantages. The harmonic method is applicable to predominantly semidiurnal or diurnal regimes, while the statistical methods can be used in mixed tidal regimes. Assisted by harmonic data, a modified skewness measure can isolate the contribution of different tidal interactions on net tidal asymmetry and also reveal its subtidal variations. The application of the skewness measure to nonstationary river tides reveals stronger tidal asymmetry during spring tides than neap tides, and the nonlinear effects of river discharges on tidal asymmetry in the upper and lower regions of long estuaries.","harmonic; residual sediment transport; skewness; tidal asymmetry","en","journal article","","","","","","","","2019-07-31","","","Coastal Engineering","","",""
"uuid:e32e92a0-8b42-44ef-8ee4-7f82e56f8f0e","http://resolver.tudelft.nl/uuid:e32e92a0-8b42-44ef-8ee4-7f82e56f8f0e","Incremental Sliding-Mode Fault-Tolerant Flight Control","Wang, Xuerui (TU Delft Control & Simulation); van Kampen, E. (TU Delft Control & Simulation); Chu, Q. P. (TU Delft Control & Simulation)","","2019","This paper proposes a novel control framework that combines the recently reformulated incremental nonlinear dynamic inversion with (higher-order) sliding-mode controllers/observers, for generic multi-input/multi-output nonlinear systems, named incremental sliding-mode control. As compared to the widely used approach that designs (higher-order) sliding-mode controllers/observers based on nonlinear dynamic inversion, the proposed incremental framework can further reduce the uncertainties while requiring less model knowledge. Because the uncertainties are reduced in the incremental framework, theoretical analyses demonstrate that the incremental sliding-mode control can passively resist a wider range of perturbations with reduced minimum possible control/observer gains. These merits are validated via numerical simulations for aircraft command tracking problems, in the presence of sudden actuator faults and structural damage.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-05","","","Control & Simulation","","",""
"uuid:f13a288b-54d1-43eb-ba44-774b6815e5f1","http://resolver.tudelft.nl/uuid:f13a288b-54d1-43eb-ba44-774b6815e5f1","Graphene Nanoribbon Based Complementary Logic Gates and Circuits","Jiang, Y. (TU Delft Computer Engineering); Cucu Laurenciu, N. (TU Delft Computer Engineering); Wang, H. (TU Delft Computer Engineering); Cotofana, S.D. (TU Delft Computer Engineering)","","2019","As CMOS feature size is reaching atomic dimensions, unjustifiable static power, reliability, and economic implications are exacerbating, thereby prompting for conducting research on new materials, devices, and/or computation paradigms. Within this context, graphene nanoribbons (GNRs), owing to graphene's excellent electronic properties, may serve as basic structures for carbon-based nanoelectronics. In this paper, we make use of the fact that GNR behavior can be modulated via top/back gate contacts to mimic a given functionality and combine complementary GNRs for constructing Boolean gates. We first introduce a generic gate structure composed of a pull-up GNR performing the gate Boolean function and a pull-down GNR performing its complement. Then, we seek GNR dimensions and gate topologies required for the design of 1-, 2-, and 3-input graphene-based Boolean gates, validate the proposed gates by means of SPICE simulation, which makes use of a non-equilibrium Green's function Landauer formalism based Verilog-A model to calculate GNR conductance, and evaluate their performance with respect to propagation delay, power consumption, and active area footprint. Simulation results indicate that, when compared with 7 nm FinFET CMOS counterparts, the proposed gates exhibit 6 × to 2 orders of magnitude smaller propagation delay, 2 to 3 orders of magnitude lower power consumption, and necessitate 2 orders of magnitude smaller active area footprint. We further present full adder (FA) and SRAM cell GNR designs, as they are currently fundamental components for the construction of any computation system. For an effective FA implementation, we introduce a 3-input MAJORITY gate, which apart of being able to directly compute FA's carry-out is an essential element in the implementation of error correcting codes codecs, which outperforms the CMOS equivalent carry-out calculation circuit by 2 and 3 orders of magnitude in terms of delay and power consumption, respectively, while requiring 2 orders of magnitude less area. The proposed FA exhibits 6.2 × smaller delay, 3 orders of magnitude less power consumption, while requiring 2 orders of magnitude less area, when compared with the 7 nm FinFET CMOS counterpart. However, because of the effective carry-out circuitry, a GNR-based n-bit ripple carry adder, whose performance is linear in the carry-out path, will be 108 × faster than an equivalent CMOS implementation. The GNR-based SRAM cell provides a slightly better resilience to dc-noise characteristics, while performance-wise has a 3.6 × smaller delay, consumes 2 orders of magnitude less power, and requires 1 order of magnitude less area than the CMOS equivalent. These results clearly indicate that the proposed GNR-based approach is opening a promising avenue toward future competitive carbon-based nanoelectronics.","Carbon-Nanoelectronics; GNR; Graphene; Graphene-based Boolean Gates","en","journal article","","","","","","Accepted author manuscript","","","","","Computer Engineering","","",""
"uuid:ea44a0be-9eeb-4912-903f-f99f3f47cf42","http://resolver.tudelft.nl/uuid:ea44a0be-9eeb-4912-903f-f99f3f47cf42","Long-Term Cumulative Effects of Intra-Annual Variability of Unsteady River Discharge on the Progradation of Delta Lobes: A Modeling Perspective","Gao, Weilun (Beijing Normal University); Shao, Dongdong (Beijing Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; Beijing Normal University); Nardin, William (University of Maryland Center for Environmental Science); Rajput, Prateek (Indian Institute of Technology Kanpur); Yang, Wei (Beijing Normal University); Sun, Tao (Beijing Normal University); Cui, Baoshan (Beijing Normal University)","","2019","Rivers, regardless of their scales and geographic locations, are characterized with natural and human-induced variability in their discharges. While previous studies have established the effects of both interannual and intra-annual variabilities of unsteady river discharge on delta morphological evolution, the long-term cumulative effects of intra-annual unsteadiness on the progradation of delta lobes has remained hitherto elusive. To address this issue, numerical experiments using simplified unsteady discharges were performed in Delft3D and compared with those assuming constant bank-full discharges. A modified box model was further used to explore the effects of varying intra-annual unsteadiness on the progradation of delta lobes at reduced computational cost. While the overall trends of the progradation and the ultimate area created were found to be similar between the unsteady discharge scenarios and their corresponding constant bank-full discharge scenarios, the nuances of intermittent zig-zag variation in natural delta lobe area were well reproduced by model simulations assuming unsteady river discharges. In addition, long-term predictions suggested the potential existence of a tipping point in the area growth trajectory beyond which the delta lobe area declines during periods of low discharge. When confounding factors such as waves and variable sediment capture ratio were further taken into consideration, simulation results for unsteady river discharge scenarios exhibit significant deviations from constant bank-full discharge scenarios. The implications of the modeling results for delta protection and restoration measures, such as the water-sediment regulation scheme in the Yellow River and artificial channel diversions in the Mississippi River Delta, are also discussed.","delta progradation; delta restoration; numerical modeling; unsteady river discharge","en","journal article","","","","","","Accepted Author Manuscript","","","","","Coastal Engineering","","",""
"uuid:0709187b-238e-4012-9af7-bca370367b6c","http://resolver.tudelft.nl/uuid:0709187b-238e-4012-9af7-bca370367b6c","Engineering Metal–Organic Frameworks for the Electrochemical Reduction of CO2: A Minireview","Wang, R. (TU Delft ChemE/Catalysis Engineering); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering); Gascon, Jorge (TU Delft ChemE/Catalysis Engineering; King Abdullah University of Science and Technology)","","2019","The electrochemical reduction of CO2 holds great promise for lowering the concentration of CO2 in the Earth′s atmosphere. However, several challenges have hindered the commercialization of this technology, including energy efficiency, the solubility of CO2 in the aqueous phase, and electrode stability. In this Minireview, we highlight and summarize the main advantages and limitations that metal–organic frameworks (MOFs) may offer in this field of research, either when used directly as electrocatalysts or when used as catalyst precursors.","carbon dioxide; electrochemistry; metal–organic frameworks; reduction; synthetic methods","en","review","","","","","","Accepted Author Manuscript","","2020-06-26","","","ChemE/Catalysis Engineering","","",""
"uuid:2a7d5730-b175-43d0-be68-2e5b72464403","http://resolver.tudelft.nl/uuid:2a7d5730-b175-43d0-be68-2e5b72464403","Chemoenzymatic Halocyclization of γ,δ-Unsaturated Carboxylic Acids and Alcohols","Younes, S.H.H. (TU Delft BT/Biocatalysis; Sohag University); Tieves, F. (TU Delft BT/Biocatalysis); Lan, Dongming (South China University of Technology); Wang, Yonghua (South China University of Technology); Süss, Philipp (Enzymicals AG, Greifswald); Brundiek, Henrike (Enzymicals AG, Greifswald); Wever, Ron (Van ’t Hoff Institute of Molecular Sciences); Hollmann, F. (TU Delft BT/Biocatalysis)","","2019","A chemoenzymatic method for the halocyclization of unsaturated alcohols and acids by using the robust V-dependent chloroperoxidase from Curvularia inaequalis (CiVCPO) as catalyst has been developed for the in situ generation of hypohalites. A broad range of halolactones and cyclic haloethers are formed with excellent performance of the biocatalyst.","biocatalysis; enzymes; etherification; haloperoxidases; lactones","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:043e1118-cc8f-47c0-b436-b5d871c6d633","http://resolver.tudelft.nl/uuid:043e1118-cc8f-47c0-b436-b5d871c6d633","Preparation of a poly(acrylic acid) based hydrogel with fast adsorption rate and high adsorption capacity for the removal of cationic dyes","Yuan, Zhenyu (East China University of Science and Technology); Wang, Jie (East China University of Science and Technology); Wang, Y. (TU Delft ChemE/Advanced Soft Matter); Liu, Q. (TU Delft ChemE/Advanced Soft Matter); Zhong, Yujie (East China University of Science and Technology); Wang, Yu (East China University of Science and Technology); Li, Li (East China University of Science and Technology); Lincoln, Stephen F. (University of Adelaide); Guo, Xuhong (East China University of Science and Technology; Shihezi University)","","2019","A biocompatible Dex-MA/PAA hydrogel was prepared through copolymerization of glycidyl methacrylate substituted dextran (Dex-MA) with acrylic acid (AA), which was applied as the adsorbent to remove cationic dyes from aqueous solutions. Dex-MA/PAA hydrogel presented a fast adsorption rate and the removal efficiency of Methylene Blue (MB) and Crystal Violet (CV) reached 93.9% and 86.4%, respectively within one minute at an initial concentration of 50 mg L-1. The adsorption equilibrium data fitted the Sips isotherm model well with high adsorption capacities of 1994 mg g-1 for MB and 2390 mg g-1 for CV. Besides, dye adsorption occurred efficiently over the pH range 3-10 and the temperature range 20-60 °C. Moreover, the removal efficiencies for MB and CV were still >95% even after five adsorption/desorption cycles which indicates the robust nature of the Dex-MA/PAA hydrogel and its potential as an eco-friendly adsorbent for water treatment.","","en","journal article","","","","","","","","","","","ChemE/Advanced Soft Matter","","",""
"uuid:976a1b95-219c-47ca-9bfe-4418b65075a7","http://resolver.tudelft.nl/uuid:976a1b95-219c-47ca-9bfe-4418b65075a7","How to predict the location of the defect levels induced by 3d transition metal ions at octahedral sites of aluminate phosphors","Qu, Bingyan (Hefei University of Technology); Zhou, Rulong (Hefei University of Technology); Wang, L. (TU Delft RST/Fundamental Aspects of Materials and Energy; Hefei University of Technology); Dorenbos, P. (TU Delft RST/Luminescence Materials)","","2019","How the 3d transition metal (TM) ions induce defect levels in wide band gap compounds and how these defect levels evolve from compound to compound is very important in understanding and predicting the luminescent properties of TM activated phosphors. This issue is discussed by studying the ground state 3dn level locations of the TM impurity ions (Sc-Zn) incorporated at the octahedral sites of many oxides. These ground state 3dn level locations are obtained by collecting the CT bands from the literature of the past 50 years and also by first-principles calculations. By taking the vacuum level as the reference, we scaled all the locations of the TM ion in 3+ and 2+ states and constructed a zig-zag-curve scheme in α-Al2O3 through connecting the 3dn ground state energies of Sc to Zn. The scheme can be extended to other aluminates easily and so offers a first estimate on where TM levels are located in compounds without complicated theoretical calculations. The estimate can be improved to a higher accuracy if the position of the valence band is known. Our work provides new insights for understanding the luminescent behavior of 3d-TM doped phosphors and may aid in developing 3d ion doped functional materials further.","","en","journal article","","","","","","Accepted Author Manuscript","","2019-11-23","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:4f2630e4-0fbd-4ece-a9c5-d220cd4dd7fa","http://resolver.tudelft.nl/uuid:4f2630e4-0fbd-4ece-a9c5-d220cd4dd7fa","Precise regional L5 positioning with IRNSS and QZSS: stand-alone and combined","Wang, Kan (Curtin University); Chen, Pei (Curtin University; Beihang University); Zaminpardaz, S. (Curtin University); Teunissen, P.J.G. (TU Delft Mathematical Geodesy and Positioning; Curtin University)","","2019","In this contribution we analyze the single-frequency L5 positioning capabilities of the two regional satellite navigation systems IRNSS and QZSS, stand alone as well as combined. The positioning analysis is done for two different baselines, having a mix of receivers, providing ambiguity-float and ambiguity-fixed positioning for models with and without zenith tropospheric delay (ZTD) estimation. The analyses include a precision analysis of the observed signals, as well as an analysis of the ambiguity resolution performance. This is done for both the multipath-uncorrected case as well as the multipath-mitigated case. It is shown that although single-system positioning performance is rather poor, the ZTD-fixed, single-epoch ambiguity success rates (ASRs) are close to 100% when the two regional systems are combined, thus providing mm-to-cm level precision for instantaneous ambiguity-fixed positioning. When the ZTD is estimated as well, only a few additional epochs are needed to get the ASRs close to 100%.","Ambiguity resolution; Ambiguity success-rate; IRNSS; L5 RTK positioning; Multipath; QZSS","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","","","","Mathematical Geodesy and Positioning","","",""
"uuid:10d459e7-f0f2-4e1a-918b-3fe5a2e31090","http://resolver.tudelft.nl/uuid:10d459e7-f0f2-4e1a-918b-3fe5a2e31090","Ship motion control based on AMBPS-PID algorithm","Wang, L. (Wuhan University of Technology); Wu, Qing (Wuhan University of Technology); Liu, Jialun (National Engineering Research Center for Water Transport Safety (WTSC); Wuhan University of Technology); Li, Shijie (Wuhan University of Technology); Negenborn, R.R. (TU Delft Transport Engineering and Logistics)","","2019","Intelligent motion control is one of the key technologies of ships. This paper studies the application of Adaptive Mutation Beetle Particle Swarm (AMBPS)-PID algorithm in ship motion control. Firstly, the ship MMG model is established. Then the BAS algorithm is introduced, and AMBPS algorithm is improved and designed on this basis. Secondly, ship heading and path following controllers are designed according to the algorithm, and rudder turning rate constraint is introduced to limit the rudder angle. Thirdly, through the test function effect analysis of AMBPS and other similar algorithms, the improved effect of this algorithm is verified. Finally, from manual tuning PID parameters to off-line and on-line optimizing parameters based on AMBPS algorithm, the optimal control parameters are obtained step by step, and the optimal heading and path following simulation results are achieved. Compared with the results of traditional PID, AMBPS-PID algorithm has a better adaptive control effect on ship motion control, reduces the error of manual tuning parameters and improves efficiency.","Motion control; heading control; path following; AMBPS-PID algorithm","en","journal article","","","","","","","","","","","Transport Engineering and Logistics","","",""
"uuid:f537ef4d-4917-4e2d-a117-dc82f548e495","http://resolver.tudelft.nl/uuid:f537ef4d-4917-4e2d-a117-dc82f548e495","State-of-the-Art Research on Motion Control of Maritime Autonomous Surface Ships","Wang, L. (Wuhan University of Technology); Wu, Qing (Wuhan University of Technology); Liu, Jialun (Wuhan University of Technology); Li, Shijie (Wuhan University of Technology); Negenborn, R.R. (TU Delft Transport Engineering and Logistics)","","2019","At present, with the development of waterborne transport vehicles, research on ship faces a new round of challenges in terms of intelligence and autonomy. The concept of maritime autonomous surface ships (MASS) has been put forward by the International Maritime Organization in 2017, in which MASS become the new focus of the waterborne transportation industry. This paper elaborates on the state-of-the-art research on motion control of MASS. Firstly, the characteristics and current research status of unmanned surface vessels in MASS and conventional ships are summarized, and the system composition of MASS is analyzed. In order to better realize the self-adaptability of the MASS motion control, the theory and algorithm of ship motion control-related systems are emphatically analyzed under the condition of classifying ship motion control. Especially, the application of intelligent algorithms in the ship control field is summarized and analyzed. Finally, this paper summarizes the challenges faced by MASS in the model establishment, motion control algorithms, and real ship experiments, and proposes the composition of MASS motion control system based on variable autonomous control strategy. Future researches on the accuracy and diversity of developments and applications to MASS motion control are suggested.","maritime autonomous surface ships (MASS); unmanned surface vehicles (USV); motion control; intelligent algorithms; autonomous control strategy","en","journal article","","","","","","","","","","","Transport Engineering and Logistics","","",""
"uuid:3aeb90a8-e115-4074-b62c-6d8d664f7178","http://resolver.tudelft.nl/uuid:3aeb90a8-e115-4074-b62c-6d8d664f7178","Probabilistic recursive reasoning for multi-agent reinforcement learning","Wen, Ying (University College London (UCL)); Yang, Yaodong (University College London (UCL)); Luo, Rui (University College London (UCL)); Wang, Jun (University College London (UCL)); Pan, W. (TU Delft Robot Dynamics)","","2019","Humans are capable of attributing latent mental contents such as beliefs, or intentions to others. The social skill is critical in everyday life to reason about the potential consequences of their behaviors so as to plan ahead. It is known that humans use this reasoning ability recursively, i.e. considering what others believe about their own beliefs. In this paper, we start from level-1 recursion and introduce a probabilistic recursive reasoning (PR2) framework for multi-agent reinforcement learning. Our hypothesis is that it is beneficial for each agent to account for how the opponents would react to its future behaviors. Under the PR2 framework, we adopt variational Bayes methods to approximate the opponents' conditional policy, to which each agent finds the best response and then improve their own policy. We develop decentralized-training-decentralized-execution algorithms, PR2-Q and PR2-Actor-Critic, that are proved to converge in the self-play scenario when there is one Nash equilibrium. Our methods are tested on both the matrix game and the differential game, which have a non-trivial equilibrium where common gradient-based methods fail to converge. Our experiments show that it is critical to reason about how the opponents believe about what the agent believes. We expect our work to contribute a new idea of modeling the opponents to the multi-agent reinforcement learning community.","","en","poster","","","","","","","","","","","Robot Dynamics","","",""
"uuid:c4a586f9-18ac-478a-973d-179000dc3401","http://resolver.tudelft.nl/uuid:c4a586f9-18ac-478a-973d-179000dc3401","Characterization of bitumen modified with pyrolytic carbon black from scrap tires","Wang, H. (TU Delft Pavement Engineering); Lu, Guoyang (Rheinisch-Westfälische Technische Hochschule); Feng, Shuyin (University of Bristol); Wen, Xiaobo (JSTI Group); Yang, Jun (Southeast University)","","2019","Pyrolytic carbon black (CB p ) from scrap tire pyrolysis is a potential modifier for the bitumen industry. Binders containing different contents of CB p were prepared and experimentally investigated to examine the effects of CB p on the electrical and thermal conductivity, conventional physical properties, rheological properties, high-temperature antirutting performance, aging resistance, and storage stability. Laboratory test results indicated that the incorporation of CB p effectively improves the electrothermal properties, rheological properties, high-temperature rutting resistance, and aging resistance. It also increases the viscosity and decreases the storage stability of bitumen. The study confirms that CB p -modified bitumen with proper selection of content can be a multifunctional paving material.","Bitumen; Carbon black; Electrical conductivity; Rheological property; Scrap tire pyrolysis; Storage stability","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:e077325a-2a09-41f4-b2f1-4cd43bc66dc6","http://resolver.tudelft.nl/uuid:e077325a-2a09-41f4-b2f1-4cd43bc66dc6","Suppression of persistent photoconductivity AlGaN/GaN heterostructure photodetectors using pulsed heating","Sun, J. (TU Delft Electronic Components, Technology and Materials); Zhan, Teng (Chinese Academy of Sciences; State Key Laboratory of Solid State Lighting); Liu, Zewen (Tsinghua University); Wang, Junxi (Chinese Academy of Sciences; State Key Laboratory of Solid State Lighting); Yi, Xiaoyan (Chinese Academy of Sciences; State Key Laboratory of Solid State Lighting); Sarro, Pasqualina M (TU Delft Electronic Components, Technology and Materials); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials; State Key Laboratory of Solid State Lighting)","","2019","This paper demonstrates a method to reduce the decay time in AlGaN/GaN photodetectors by a pulsed heating mode. A suspended AlGaN/GaN heterostructure photodetector integrated with a micro-heater is fabricated and characterized under ultraviolet illumination. We have observed that the course of persistent photoconductivity was effectively accelerated by applying pulsed heating. The decay time is significantly reduced from 175 s by DC heating to 116 s by 50 Hz pulsed heating at the same power (280 mW). With the same pulse duty cycle and a 50 Hz pulsed heating frequency, a reduction of 30%-45% in decay time is measured compared to DC heating.","pulsed heating; AlGaN; GaN; UV detector","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-08-02","","","Electronic Components, Technology and Materials","","",""
"uuid:82608b6e-6040-4961-8e98-2be26891cb5d","http://resolver.tudelft.nl/uuid:82608b6e-6040-4961-8e98-2be26891cb5d","A forward collision avoidance algorithm based on driver braking behavior","Xiong, Xiaoxia (Jiangsu University); Wang, M. (TU Delft Transport and Planning); Cai, Yingfeng (Jiangsu University); Cheng, Long (Jiangsu University); Farah, H. (TU Delft Transport and Planning); Hagenzieker, Marjan (TU Delft Transport and Planning)","","2019","Measuring risk is critical for collision avoidance. The paper aims to develop an online risk level classification algorithm for forward collision avoidance systems. Assuming risk levels are reflected by braking profiles, deceleration curves from critical evasive braking events from the Virginia “100-car” database were first extracted. The curves are then clustered into different risk levels based on spectrum clustering, using curve distance and curve changing rate as dissimilarity metrics among deceleration curves. Fuzzy logic rules of safety indicators at critical braking onset for risk classification were then extracted according to the clustered risk levels. The safety indicators include time to collision, time headway, and final relative distance under emergency braking, which characterizes three kinds of uncertain critical conditions respectively. Finally, the obtained fuzzy risk level classification algorithm was tested and compared with other Automatic Emergency Braking (AEB) algorithms under Euro-NCAP testing scenarios in simulation. Results show the proposed algorithm is promising in balancing the objectives of avoiding collision and reducing interference with driver's normal driving compared with other algorithms.","Cluster analysis; Collision avoidance; Deceleration curve; Driver braking behavior profile; Dynamic time warping; Fuzzy logic","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-11-16","","","Transport and Planning","","",""
"uuid:72757c08-a7e9-4fcc-9795-18de82c2631f","http://resolver.tudelft.nl/uuid:72757c08-a7e9-4fcc-9795-18de82c2631f","Space-time topology optimization for additive manufacturing: Concurrent optimization of structural layout and fabrication sequence","Wang, W. (TU Delft Materials and Manufacturing; Dalian University of Technology); Munro, D.P. (TU Delft Computational Design and Mechanics); Wang, C.C. (TU Delft Materials and Manufacturing); van Keulen, A. (TU Delft Computational Design and Mechanics); Wu, J. (TU Delft Materials and Manufacturing)","","2019","The design of optimal structures and the planning of (additive manufacturing) fabrication sequences have been considered typically as two separate tasks that are performed consecutively. In the light of recent advances in robot-assisted (wire-arc) additive manufacturing which enable addition of material along curved surfaces, we present a novel topology optimization formulation which concurrently optimizes the structure and the fabrication sequence. For this, two sets of design variables, i.e., a density field for defining the structural layout, and a time field which determines the fabrication process order, are simultaneously optimized. These two fields allow to generate a sequence of intermediate structures, upon which manufacturing constraints (e.g., fabrication continuity and speed) are imposed. The proposed space-time formulation is general, and is demonstrated on three fabrication settings, considering self-weight of the intermediate structures, process-dependent critical loads, and time-dependent material properties.","Additive manufacturing; Manufacturing process planning; Space-time optimization; Topology optimization","en","journal article","","","","","","","","","","","Materials and Manufacturing","","",""
"uuid:1268b5aa-2f7e-4a91-9760-840ae5629209","http://resolver.tudelft.nl/uuid:1268b5aa-2f7e-4a91-9760-840ae5629209","Suspended tungsten trioxide (WO3) gate AlGaN/GaN heterostructure deep ultraviolet detectors with integrated micro-heater","Sun, J. (TU Delft Electronic Components, Technology and Materials); Zhan, Teng (Chinese Academy of Sciences; State Key Laboratory of Solid State Lighting); Liu, Zewen (Tsinghua University); Wang, Junxi (Chinese Academy of Sciences; State Key Laboratory of Solid State Lighting); Yi, Xiaoyan (Chinese Academy of Sciences; State Key Laboratory of Solid State Lighting); Sarro, Pasqualina M (TU Delft Electronic Components, Technology and Materials); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials; State Key Laboratory of Solid State Lighting)","","2019","A suspended WO3-gate AlGaN/GaN heterostructure photodetector integrated with a micro-heater is micro-fabricated and characterized for ultraviolet photo detection. The transient optical characteristics of the photodetector at different temperatures are studied. The 2DEG-based photodetector shows a recovery (170 s) time under 240 nm illumination at 150 ℃. The measured spectral response of WO3-gate AlGaN/GaN heterostructure shows a high response in deep ultraviolet range. Responsivity at 240 nm wavelength is 4600 A/W at 0.5 V bias. These characteristics support the feasibility of a high accuracy deep UV detector based on the suspended AlGaN/GaN heterostructure integrated with a micro-heater.","","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:5c0cb0cd-e37a-4717-9511-3f468959c80c","http://resolver.tudelft.nl/uuid:5c0cb0cd-e37a-4717-9511-3f468959c80c","An extensive investigation of an eco-approach controller under a partially connected and automated vehicle environment","Jiang, Huifu (Ministry of Transport); Hu, Jia (Tongji University); Park, Byungkyu Brian (University of Virginia); Wang, M. (TU Delft Transport and Planning); Zhou, Wei (Ministry of Transport)","","2019","This study evaluated the performance of an eco-approach control system at signalized intersections under a partially connected and automated vehicle (CAV) environment. This system has the first eco-approach controller able to function with the existence of surrounding human-driven traffic. A previous evaluation only confirmed its benefits. The purpose of this study was to conduct a further extensive test on the controller to identify room for improvement. Two different networks were tested, including an isolated signalized intersection and a corridor with two signalized intersections. The measures of effectiveness (MOEs) adopted were throughput and fuel consumption. All the before-and-after MOEs were compared using t-tests. The results indicate that the controller generally improved the fuel efficiency without harm to the mobility, and its environmental performance was affected by the minimum CAV speed, green ratio, congestion level, and marker penetration rate of CAVs. A detailed investigation revealed that no significant environmental benefit was generated under high congestion levels when the minimum speed of CAVs was more than 20 mph, and the shockwaves caused by the eco-approach control may result in a gating effect that reduces the throughput at the upstream intersection of the corridor under high congestion levels.","Eco-approach; Fuel consumption; Partially connected and automated vehicles environment; Signalized intersections; Throughput","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:d88e0dff-8de0-4dfe-9134-6d4ab83ffce7","http://resolver.tudelft.nl/uuid:d88e0dff-8de0-4dfe-9134-6d4ab83ffce7","Rheological properties, compatibility, and storage stability of SBS latex-modified asphalt","Ren, S. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Fan, Weiyu (China University of Petroleum (East China)); Wang, H. (TU Delft Pavement Engineering); Erkens, S. (TU Delft Pavement Engineering)","","2019","A styrene-butadiene-styrene (SBS) latex modifier can be used for asphalt modification due to the fact of its energy-saving, construction convenience, and economic advantages. The objective of this study was to investigate the influence of asphalt type and SBS latex dosage on the rheological properties, compatibility, and storage stability of asphalt through temperature and frequency sweep, steady-state flow, multiple stress creep and recovery (MSCR) tests, Cole-Cole plots and thermal storage tests. The results indicated that high SBS latex content is beneficial for improving anti-rutting, anti-fatigue, viscous flow resistance, and elastic recovery abilities of modified asphalt. The chemical composition of asphalt had a significant effect on the properties of the SBS latex-modified asphalt. High asphaltenes and low resins were favorable to enhancing anti-rutting and recovery properties but weakened the anti-fatigue, compatibility, and storage stability of modified asphalt. Furthermore, compared to SBS particle-modified asphalt, SBS latex-modified asphalt had greater rutting and fatigue resistance. However, SBS latex-modified asphalt had some disadvantages in compatibility and storage stability. Comprehensively considering the balance of viscoelastic properties, compatibility, and storage stability of SBS latex-modified asphalt, the mixing dosage of SBS latex modifier is recommended at 4.0 wt% which could feasibly replace SBS particle in asphalt modification.","Compatibility; Rheological properties; SBS latex; SBS-modified asphalt; Storage stability","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:45b6b4a6-5d9d-4aa1-8c21-8db01c3e2a0d","http://resolver.tudelft.nl/uuid:45b6b4a6-5d9d-4aa1-8c21-8db01c3e2a0d","Risk analysis of earth-rock dam breach based on dynamic Bayesian network","Li, Zongkun (Zhengzhou University); Wang, Te (Zhengzhou University); Ge, W. (TU Delft Safety and Security Science; Zhengzhou University); Wei, Dong (Zhengzhou University); Li, Hanyu (Zhengzhou University)","","2019","Despite the fact that the Bayesian network has great advantages in logical reasoning and calculation compared with the other traditional risk analysis methods, there are still obvious shortcomings in the study of dynamic risk. The risk factors of the earth-rock dam breach are complex, which vary with time during the operation period. Static risk analysis, limited to a specific period of time, cannot meet the needs of comprehensive assessment and early warning. By introducing time factors, a dynamic Bayesian network model was established to study the dynamic characteristics of dam-breach probability. Combined with the calculation of the conditional probability of nodes based on the Leaky Noisy-Or gate extended model, the reasoning results of Bayesian networks were modified by updating the data of different time nodes. Taking an earth-rock dam as an example, the results show that it has less possibility to breach and keep stable along the time axis. Moreover, the factors with vulnerability and instability were found effective, which could provide guidance for dam risk management.","Conditional probability; Dam breach; Dynamic Bayesian network; Earth-rock dam; Risk","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:73588eef-c914-4082-9cb6-c3bd74dc45cc","http://resolver.tudelft.nl/uuid:73588eef-c914-4082-9cb6-c3bd74dc45cc","Data based violated behavior analysis of taxi driver in metropolis in China","Yao, Jiao (University of Shanghai for Science and Technology); Ni, Yiling (University of Shanghai for Science and Technology); Zhao, J. (TU Delft Transport and Planning); Niu, Huiwei (University of Shanghai for Science and Technology); Liu, Shanyong (University of Shanghai for Science and Technology); Zheng, Yuhui (Nanjing University of Information Sciences and Technology); Wang, Jin (Changsha University of Science and Technology; Fujian University of Technology)","","2019","Violation probability of taxi drivers in metropolis is far more than that of normal drivers because they are labor-intensive, overconfident of self-driving skill, and always searching potential customers, sometimes even picking up or dropping off passengers randomly. In this paper, four types of violated behavior of taxi drivers in metropolis were first summarized, based on which corresponding scale table was initial designed with social statistical method. Furthermore, with certain samples, relative item analysis, exploratory factor analysis, validity analysis and reliability analysis were conducted to verify validity of the initial scale table, based on which some improvements were made, and we can see that the modified scale table in the paper has high fitness degree, good reliability and validity to detect violated behavior of taxi driver accurately. Finally, large area survey data of taxi driver questionnaire from Shanghai was collected with the modified scale table above, the analysis results showed that among four types of violated behavior of taxi drivers in metropolis, the probability over-speed is top to 89.57%, in which probabilities of behaviors of “driving over-speed at mid-night” and “accelerating to across the intersection during the yellow signal” are top to 64.2% and 58.2% respectively, which is meaningful for the improvement of taxi drivers’ behaviors specification and traffic safety regulation.","Exploratory factor analysis; Scale table design; Taxi driver; Validity analysis; Violated behavior","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:9414753f-1de7-4097-b945-c96738eabce5","http://resolver.tudelft.nl/uuid:9414753f-1de7-4097-b945-c96738eabce5","Motorized capsule for shadow-free OCT imaging and synchronous beam control","López-Marín, Antonio (Erasmus MC); Springeling, Geert (Erasmus MC); Beurskens, Robert (Erasmus MC); van Beusekom, Heleen (Erasmus MC); van der Steen, A.F.W. (TU Delft ImPhys/Acoustical Wavefield Imaging; Erasmus MC; Chinese Academy of Sciences); Koch, Arjun D. (Erasmus MC); Bouma, Brett E. (Harvard Medical School); Huber, Robert (University of Lübeck); Soest, Gijs V.A.N. (Erasmus MC); Wang, Tianshi (Erasmus MC)","","2019","We demonstrate a tethered motorized capsule for unobstructed optical coherence tomography (OCT) imaging of the esophagus. By using a distal reflector design, we avoided the common shadow artifact induced by the motor wires. A synchronous driving technique features three types of beam-scanning modes of the capsule, i.e., circumferential beam scanning, localized beam scanning, and accurate beam positioning. We characterized these three modes and carried out ex vivo imaging experiments using the capsule. The results show that the capsule can potentially be a useful tool for diagnostic OCT imaging and OCT-guided biopsy and therapy of the esophagus.","","en","journal article","","","","","","","","","","","ImPhys/Acoustical Wavefield Imaging","","",""
"uuid:342706f1-eb8a-4a83-89a5-68a9eeb2ec26","http://resolver.tudelft.nl/uuid:342706f1-eb8a-4a83-89a5-68a9eeb2ec26","High moisture accelerated mechanical behavior degradation of phosphor/silicone composites used in white light-emitting diodes","Fan, J. (TU Delft Electronic Components, Technology and Materials; Hohai University; Changzhou Institute of Technology Research for Solid State Lighting); Wang, Zhen (Hohai University; Changzhou Institute of Technology Research for Solid State Lighting); Zhang, Xunwei (Hohai University); Deng, Zentao (Lamar University); Fan, Xuejun (Lamar University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2019","In a high-power white light emitting diode (LED) package, the phosphor/silicone composite is typically used for photometric and colorimetric conversions, ultimately producing the white light. However, the phosphor/silicone composite is always exposed under harsh environments with high temperature, high blue light irradiation and high moisture when the LED operates. Therefore, its reliability issue has become one of the critical bottlenecks to improve the lifetime of a high-power white LED package. As the curing process and mechanical behavior of phosphor/silicone composite essentially determine its reliability, this paper firstly uses an in situ viscosity monitoring approach combined with Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR) analysis to explain the curing mechanism of a phosphor/silicone composite by taking the effects of temperature and phosphor mass fraction into consideration. Then, the mechanical properties of phosphor/silicone composites aged under a long-term high moisture condition are evaluated by using the tensile test. Meanwhile, the finite element (FE) simulations, the Mori-Tanaka theoretical estimations and the microstructure analysis are applied to investigate the high moisture induced degradation mechanisms. The results show that: (1) the in situ measured isothermal viscosity curves of both pristine silicone and phosphor/silicone composites follow the Arrhenius empirical model, and high temperature and high phosphor mass fraction can increase the curing rate; (2) the hydrosilylation reaction between silicones determines the curing mechanism of phosphor/silicone composite; (3) the tensile test, FE simulation and Mori-Tanaka theoretical prediction results confirm that the Young's modulus of phosphor/silicone composite increases by gradually adding phosphors; and (4) the Young's modulus of phosphor/silicone composite increases after the high moisture ageing test, which can be attributed to the oxidation and cross-linking reaction of silicone and the hydrolysis of phosphor powders.","Curing mechanism; Light-emitting diode; Mechanical properties; Moisture; Phosphor/silicone composite","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:94c687d1-76b9-4cb5-bf8c-2d94d69ca58c","http://resolver.tudelft.nl/uuid:94c687d1-76b9-4cb5-bf8c-2d94d69ca58c","A study on the effect of ceramic polishing powder on the nucleation and growth of hydrates in cement paste","Wang, Liquan (Guangzhou University); Liu, Ziyang (Guangzhou University); Xu, Shida (Guangzhou University); Ouyang, Xiaowei (Guangzhou University); Ouyang, Dong (Jinan University); Jiao, Chujie (Guangzhou University); Zhang, Y. (TU Delft Materials and Environment)","","2019","The production of cement leads to a large amount of CO2 emission. Using industrial waste slag, such as ceramic polishing powder (PP), to replace part of Portland cement can reduce the pollution caused by the cement industry and solid waste disposal. In order to use PP as a replacement for cement, its effects on the properties of cement paste need to be clarified. In this study, the effect of PP on the nucleation and growth of hydrates in cement paste at very early ages was investigated. Quartz was used as a reference. The interactions of their surface with various ions in cement paste solution, which has an important effect on the nucleation and growth of hydrates, were studied by using the zeta potential test. The morphology of the nucleus and crystal of hydrates was investigated by using SEM. The zeta potential measurements showed that the affinity of the surface of PP and quartz to ions in the pore solution of cement paste is similar. The image of SEM indicated that there is also not much difference in the crystallization of hydrates on the surfaces of PP and quartz. These evidences suggested that PP has similar surface charge properties as quartz, and its effects on the properties of cement paste are the same as that of quartz. From the viewpoint of the effect on very early hydration, PP can be used in cement paste, similar to quartz power.","C-S-H; Cement paste; Ceramic polishing powder; Crystal; Ions interaction; Nucleation; Quartz; Zeta potential","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:305a7400-3f5b-4780-8c83-b331873927ce","http://resolver.tudelft.nl/uuid:305a7400-3f5b-4780-8c83-b331873927ce","Ab initio exact diagonalization simulation of the Nagaoka transition in quantum dots","Wang, Yao (Harvard University); Dehollain, Juan Pablo (Kavli institute of nanoscience Delft; University of Technology Sydney); Liu, Fang (Massachusetts Institute of Technology); Mukhopadhyay, U. (TU Delft QCD/Vandersypen Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Rudner, Mark S. (University of Copenhagen); Vandersypen, L.M.K. (TU Delft TU Delft Library; TU Delft QCD/Vandersypen Lab; TU Delft QN/Vandersypen Lab); Demler, Eugene (Harvard University)","","2019","Recent progress of quantum simulators provides insight into the fundamental problems of strongly correlated systems. To adequately assess the accuracy of these simulators, the precise modeling of the many-body physics, with accurate model parameters, is crucially important. In this paper, we employed an ab initio exact diagonalization framework to compute the correlated physics of a few electrons in artificial potentials. We apply this approach to a quantum-dot system and study the magnetism of the correlated electrons, obtaining good agreement with recent experimental measurements in a plaquette. Through control of dot potentials and separation, including geometric manipulation of tunneling, we examine the Nagaoka transition and determine the robustness of the ferromagnetic state. While the Nagaoka theorem considers only a single-band Hubbard model, in this work we perform extensive ab initio calculations that include realistic multiorbital conditions in which the level splitting is smaller than the interactions. This simulation complements the experiments and provides insight into the formation of ferromagnetism in correlated systems. More generally, our calculation sets the stage for further theoretical analysis of analog quantum simulators at a quantitative level.","","en","journal article","","","","","","","","","","TU Delft Library","QCD/Vandersypen Lab","","",""
"uuid:67537835-f37d-4780-8950-23582967e01f","http://resolver.tudelft.nl/uuid:67537835-f37d-4780-8950-23582967e01f","Novel high performance poly(p-phenylene benzobisimidazole) (PBDI) membranes fabricated by interfacial polymerization for H 2 separation","Shan, M. (TU Delft ChemE/Catalysis Engineering); Liu, X. (TU Delft ChemE/Catalysis Engineering); Wang, X. (TU Delft ChemE/Catalysis Engineering); Liu, Z. (TU Delft OLD ChemE/Organic Materials and Interfaces); Iziyi, H. (Student TU Delft); Ganapathy, S. (TU Delft RST/Storage of Electrochemical Energy); Gascon, Jorge (TU Delft ChemE/Catalysis Engineering; King Abdullah University of Science and Technology); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering)","","2019","Membranes with high selectivity and permeance are needed to reduce energy consumption in hydrogen purification and pre-combustion CO 2 capture. Polybenzimidazole (PBI) is one of the leading membrane materials for this separation. In this study, we present superior novel supported PBI (poly(p-phenylene benzobisimidazole), PBDI) membranes prepared by a facile interfacial polymerization (IP) method. The effect of IP reaction duration, operating temperature and pressure on membrane separation performance was systematically investigated. The best performance was achieved for membranes prepared in a 2 h reaction time. The resulting membranes display an ultrahigh mixed-gas H 2 /CO 2 selectivity of 23 at 423 K together with an excellent H 2 permeance of 241 GPU, surpassing the membrane performance of conventional polymers (the 2008 Robeson upper bound). These separation results, together with the facile manufacture, pressure resistance, long-term thermostability (>200 h) and economic analysis, recommend the PBDI membranes for industrial use in H 2 purification and pre-combustion CO 2 capture. Besides, PBDI membranes possess high selectivities towards H 2 /N 2 (up to 60) and H 2 /CH 4 (up to 48) mixtures, indicating their potential applications in ammonia synthesis and syngas production.","","en","journal article","","","","","","Accepted Author Manuscript","","2020-03-14","","","ChemE/Catalysis Engineering","","",""
"uuid:59072523-6390-4d96-a9ee-aa4740d0b63d","http://resolver.tudelft.nl/uuid:59072523-6390-4d96-a9ee-aa4740d0b63d","High-performance polybenzimidazole membranes for helium extraction from natural gas","Wang, X. (TU Delft ChemE/Catalysis Engineering); Shan, M. (TU Delft ChemE/Transport Phenomena); Liu, X. (TU Delft ChemE/Catalysis Engineering); Wang, M. (TU Delft Engineering Thermodynamics); Doherty, Cara M. (Oceans and Atmosphere); Osadchii, D. (TU Delft ChemE/Catalysis Engineering); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering)","","2019","Increasing helium use in research and production processes necessitates separation techniques to secure sufficient supply of this noble gas. Energy-efficient helium production from natural gas is still a big challenge. Membrane gas separation technology could play an important role. Herein, a novel poly(p-phenylene benzobisimidazole) (PBDI) polymeric membrane for helium extraction from natural gas with low He abundance is reported. The membranes were fabricated by a facile interfacial polymerization at room temperature. The thin and defect-free membrane structure was manipulated by the confined polymerization of monomers diffusing through the interface between two immiscible liquids. Both He/CH4 selectivity and He permeance are competitive over those of other commercial perfluoropolymers. Even at low He content of 1%, separation performance of the PBDI membrane transcended the current upper bound. The unprecedented selectivity (>1000) together with the excellent stability (∼360 h) endows PBDI membranes with a great potential for energy-efficient industrial recovery and production of this precious He resources from reservoirs with low abundance.","He separation; interfacial polymerization; membrane; natural gas; polybenzimidazole","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:5c6f820d-aaa4-42ea-9827-3e794de6ba0b","http://resolver.tudelft.nl/uuid:5c6f820d-aaa4-42ea-9827-3e794de6ba0b","Deterministic creation and braiding of chiral edge vortices","Beenakker, C.W.J. (Universiteit Leiden); Baireuther, P. (Universiteit Leiden); Herasymenko, Y. (Universiteit Leiden); Adagideli, I. (Sabancı University); Wang, L. (TU Delft QN/Akhmerov Group; Kavli institute of nanoscience Delft); Akhmerov, A.R. (TU Delft QN/Akhmerov Group; Kavli institute of nanoscience Delft)","","2019","Majorana zero modes in a superconductor are midgap states localized in the core of a vortex or bound to the end of a nanowire. They are anyons with non-Abelian braiding statistics, but when they are immobile one cannot demonstrate this by exchanging them in real space and indirect methods are needed. As a real-space alternative, we propose to use the chiral motion along the boundary of the superconductor to braid a mobile vortex in the edge channel with an immobile vortex in the bulk. The measurement scheme is fully electrical and deterministic: Edge vortices (π-phase domain walls) are created on demand by a voltage pulse at a Josephson junction and the braiding with a Majorana zero mode in the bulk is detected by the charge produced upon their fusion at a second Josephson junction.","","en","journal article","","","","","","","","","","","QN/Akhmerov Group","","",""
"uuid:24739610-fc02-4113-9379-5a9647a9675e","http://resolver.tudelft.nl/uuid:24739610-fc02-4113-9379-5a9647a9675e","Self-orienting hydrogel micro-buckets as novel cell carriers","Liu, Q. (TU Delft ChemE/Advanced Soft Matter; Beijing Normal University); Zhao, M. (TU Delft (OLD) MSE-1); Mytnyk, S. (TU Delft ChemE/Product and Process Engineering); Klemm, B. (TU Delft ChemE/Advanced Soft Matter); Zhang, K. (TU Delft ChemE/Advanced Soft Matter); Wang, Y. (TU Delft ChemE/Advanced Soft Matter); Yan, Dadong (Beijing Normal University); Mendes, E. (TU Delft ChemE/Advanced Soft Matter); van Esch, J.H. (TU Delft ChemE/Advanced Soft Matter)","","2019","Hydrogel microparticles are important in materials engineering, but their applications remain limited owing to the difficulties associated with their manipulation. Herein, we report the self-orientation of crescent-shaped hydrogel microparticles and elucidate its mechanism. Additionally, the microparticles were used, for the first time, as micro-buckets to carry living cells. In aqueous solution, the microparticles spontaneously rotated to a preferred orientation with the cavity facing up. We developed a geometric model that explains the self-orienting behavior of crescent-shaped particles by minimizing the potential energy of this specific morphology. Finally, we selectively modified the particles’ cavities with RGD peptide and exploited their preferred orientation to load them with living cells. Cells could adhere, proliferate, and be transported and released in vitro. These micro-buckets hold a great potential for applications in smart materials, cell therapy, and biological engineering.","cell carriers; hydrogels; microfluidics; self-orientation; soft matter","en","journal article","","","","","","","","","","","ChemE/Advanced Soft Matter","","",""
"uuid:4c4508a9-e978-4030-af4d-fe5cf5918451","http://resolver.tudelft.nl/uuid:4c4508a9-e978-4030-af4d-fe5cf5918451","Selectivity Map for Molecular Beam Epitaxy of Advanced III-V Quantum Nanowire Networks","Aseev, P. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Fursina, A. (TU Delft QRD/Kouwenhoven Lab; Microsoft Quantum Lab Delft); Boekhout, F. (TU Delft QRD/Kouwenhoven Lab; TU Delft Safety and Security; TU Delft QuTech Advanced Research Centre); Borsoi, F. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Heedt, S. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, Guanzhong (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Binci, L. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Koops, R. (TU Delft BUS/General; TU Delft Safety and Security; TU Delft QuTech Advanced Research Centre); Uccelli, E. (TU Delft BUS/General; TU Delft Safety and Security; TU Delft QuTech Advanced Research Centre); Kouwenhoven, Leo P. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Microsoft Quantum Lab Delft; Kavli institute of nanoscience Delft); Caroff-Gaonac'h, P. (TU Delft QRD/Kouwenhoven Lab; Microsoft Quantum Lab Delft)","","2019","Selective-area growth is a promising technique for enabling of the fabrication of the scalable III-V nanowire networks required to test proposals for Majorana-based quantum computing devices. However, the contours of the growth parameter window resulting in selective growth remain undefined. Herein, we present a set of experimental techniques that unambiguously establish the parameter space window resulting in selective III-V nanowire networks growth by molecular beam epitaxy. Selectivity maps are constructed for both GaAs and InAs compounds based on in situ characterization of growth kinetics on GaAs(001) substrates, where the difference in group III adatom desorption rates between the III-V surface and the amorphous mask area is identified as the primary mechanism governing selectivity. The broad applicability of this method is demonstrated by the successful realization of high-quality InAs and GaAs nanowire networks on GaAs, InP, and InAs substrates of both (001) and (111)B orientations as well as homoepitaxial InSb nanowire networks. Finally, phase coherence in Aharonov-Bohm ring experiments validates the potential of these crystals for nanoelectronics and quantum transport applications. This work should enable faster and better nanoscale crystal engineering over a range of compound semiconductors for improved device performance.","epitaxy; GaAs; III?V nanowire; InAs; molecular beam epitaxy; Selective-area growth; selectivity","en","journal article","","","","","","","","","","","QRD/Kouwenhoven Lab","","",""
"uuid:f75f9555-0f4a-4b08-82ee-01659a56fd69","http://resolver.tudelft.nl/uuid:f75f9555-0f4a-4b08-82ee-01659a56fd69","Hierarchically Compartmentalized Supramolecular Gels through Multilevel Self-Sorting","Wang, Y. (TU Delft ChemE/Advanced Soft Matter); Lovrak, M. (TU Delft ChemE/Advanced Soft Matter); Liu, Q. (TU Delft ChemE/Advanced Soft Matter); Maity, C. (TU Delft ChemE/Advanced Soft Matter); le Sage, V.A.A. (TU Delft ChemE/Advanced Soft Matter); Guo, Xuhong (East China University of Science and Technology; Shihezi University); Eelkema, R. (TU Delft ChemE/Advanced Soft Matter); van Esch, J.H. (TU Delft ChemE/Advanced Soft Matter)","","2019","Hierarchical compartmentalization through the bottom-up approach is ubiquitous in living cells but remains a formidable task in synthetic systems. Here we report on hierarchically compartmentalized supramolecular gels that are spontaneously formed by multilevel self-sorting. Two types of molecular gelators are formed in situ from nonassembling building blocks and self-assemble into distinct gel fibers through a kinetic self-sorting process; interestingly, these distinct fibers further self-sort into separated microdomains, leading to microscale compartmentalized gel networks. Such spontaneously multilevel self-sorting systems provide a ""bottom-up"" approach toward hierarchically structured functional materials and may play a role in intracellular organization.","","en","journal article","","","","","","","","","","","ChemE/Advanced Soft Matter","","",""
"uuid:6dd5646c-f2bc-455e-bd06-05a7a6607ca6","http://resolver.tudelft.nl/uuid:6dd5646c-f2bc-455e-bd06-05a7a6607ca6","Identifying protein complexes from dynamic temporal interval protein-protein interaction networks","Zhang, Jinxiong (South China University of Technology; Guangxi University); Zhong, Cheng (Guangxi University); Lin, H.X. (TU Delft Mathematical Physics); Wang, Mian (Guangxi University)","","2019","Identification of protein complex is very important for revealing the underlying mechanism of biological processes. Many computational methods have been developed to identify protein complexes from static protein-protein interaction (PPI) networks. Recently, researchers are considering the dynamics of protein-protein interactions. Dynamic PPI networks are closer to reality in the cell system. It is expected that more protein complexes can be accurately identified from dynamic PPI networks. In this paper, we use the undulating degree above the base level of gene expression instead of the gene expression level to construct dynamic temporal PPI networks. Further we convert dynamic temporal PPI networks into dynamic Temporal Interval Protein Interaction Networks (TI-PINs) and propose a novel method to accurately identify more protein complexes from the constructed TI-PINs. Owing to preserving continuous interactions within temporal interval, the constructed TI-PINs contain more dynamical information for accurately identifying more protein complexes. Our proposed identification method uses multisource biological data to judge whether the joint colocalization condition, the joint coexpression condition, and the expanding cluster condition are satisfied; this is to ensure that the identified protein complexes have the features of colocalization, coexpression, and functional homogeneity. The experimental results on yeast data sets demonstrated that using the constructed TI-PINs can obtain better identification of protein complexes than five existing dynamic PPI networks, and our proposed identification method can find more protein complexes accurately than four other methods.","","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:0475d555-416d-4feb-97fb-066c951c6c5a","http://resolver.tudelft.nl/uuid:0475d555-416d-4feb-97fb-066c951c6c5a","How To Break the Janus Effect of H 2 O 2 in Biocatalysis? Understanding Inactivation Mechanisms To Generate more Robust Enzymes","Zhao, Ze Xin (South China University of Technology); Lan, Dongming (South China University of Technology); Tan, Xiyu (South China University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis); Bornscheuer, Uwe T. (Greifswald University); Yang, Bo (South China University of Technology); Wang, Yonghua (South China University of Technology)","","2019","H 2 O 2 , is an attractive oxidant for synthetic chemistry, especially if activated as percarboxylic acid. H 2 O 2 , however, is also a potent inactivator of enzymes. Protein engineering efforts to improve enzyme resistance against H 2 O 2 in the past have mostly focused on tedious probabilistic directed evolution approaches. Here we demonstrate that a rational approach combining multiscale MD simulations and Born-Oppenheimer ab initio QM/MM MD simulations is an efficient approach to rapidly identify improved enzyme variants. Thus, the lipase from Penicillium camembertii was redesigned with a single mutation (I260R), leading to drastic improvements in H 2 O 2 resistance while maintaining the catalytic activity. Also the extension of this methodology to other enzymes is demonstrated.","epoxidation; H O; inactivation; lipase; multiscale MD; QM/MM MD","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-08-28","","","BT/Biocatalysis","","",""
"uuid:e3681529-d8df-4f01-9b88-fc43c1b205e9","http://resolver.tudelft.nl/uuid:e3681529-d8df-4f01-9b88-fc43c1b205e9","A network-centric approach for estimating trust between open source software developers","Sapkota, Hitesh (Rochester Institute of Technology); Murukannaiah, P.K. (TU Delft Interactive Intelligence); Wang, Yi (Rochester Institute of Technology)","","2019","Trust between developers influences the success of open source software (OSS) projects. Although existing research recognizes the importance of trust, there is a lack of an effective and scalable computational method to measure trust in an OSS community. Consequently, OSS project members must rely on subjective inferences based on fragile and incomplete information for trust-related decision making. We propose an automated approach to assist a developer in identifying the trustworthiness of another developer. Our two-fold approach, first, computes direct trust between developer pairs who have interacted previously by analyzing their interactions via natural language processing. Second, we infer indirect trust between developers who have not interacted previously by constructing a community-wide developer network and propagating trust in the network. A large-scale evaluation of our approach on a GitHub dataset consisting of 24,315 developers shows that contributions from trusted developers are more likely to be accepted to a project compared to contributions from developers who are distrusted or lacking trust from project members. Further, we develop a pull request classifier that exploits trust metrics to effectively predict the likelihood of a pull request being accepted to a project, demonstrating the practical utility of our approach.","","en","journal article","","","","","","","","","","","Interactive Intelligence","","",""
"uuid:e27fa935-b576-4eec-826f-050499979d79","http://resolver.tudelft.nl/uuid:e27fa935-b576-4eec-826f-050499979d79","An Efficient Strategy for the Production of Epoxidized Oils: Natural Deep Eutectic Solvent-Based Enzymatic Epoxidation","Zhang, Tianyu (South China University of Technology); Ma, Yunjian (South China University of Technology); Tan, Chin Ping (Universiti Putra Malaysia); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Jianrong (South China University of Technology); Yang, Bo (South China University of Technology); Wang, Yonghua (South China University of Technology)","","2019","Poor H 2 O 2 -resistance by enzymes is a key bottleneck in the epoxidation process of oil by enzymatic methods. In this study, the stability of three lipases, from Aspergillus oryzae lipase (AOL), Aspergillus fumigatus lipase B (AflB), and marine Janibacter (MAJ1), in the presence of H 2 O 2 was evaluated in different types of natural deep eutectic solvents (NADES). This stability was strengthened significantly in the NADES compared to the buffer. Specifically, AOL retained 84.7% of its initial activity in the presence of choline chloride/sorbitol (1:1 M ratio) and 3 mol L −1 H 2 O 2 after 24 h incubation at 40°C. In addition, the two-phase epoxidation process was optimized with AOL in ChCl/sorbitol to reach up to 96.8% conversion under the optimized conditions (molar ratio of octanoic acid/H 2 O 2 /C=C-bonds = 0.3:1.5:1, enzyme loading of 15 U g −1 of soybean oil, ChCl/sorbitol content of 70.0% of the weight of hydrophilic phase, and reaction temperature of 50°C). Moreover, the lipase dispersed in NADES retained approximately 66% of its initial activity after being used for seven batch cycles. Overall, NADES-based enzymatic epoxidation is a feasible and promising strategy for the synthesis of epoxidized oils.","Enzyme catalysis; Epoxidation; Lipase; Natural deep eutectic solvent; Soybean oil","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-09-20","","","BT/Biocatalysis","","",""
"uuid:6c006057-759e-47e0-b392-4546713cce20","http://resolver.tudelft.nl/uuid:6c006057-759e-47e0-b392-4546713cce20","From the headwater to the delta: A synthesis of the basin-scale sediment load regime in the Changjiang River","Guo, Leicheng (East China Normal University); Su, Ni (Tongji University); Townend, Ian (University of Southampton; East China Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; East China Normal University; Deltares); Zhu, C. (TU Delft Coastal Engineering; East China Normal University); Wang, Xianye (East China Normal University); Zhang, Yuning (East China Normal University); He, Qing (East China Normal Univeristy)","","2019","Many large rivers in the world delivers decreasing sediment loads to coastal oceans owing to reductions in sediment yield and disrupted sediment deliver. Understanding the sediment load regime is a prerequisite of sediment management and fluvial and deltaic ecosystem restoration. This work examines sediment load changes across the Changjiang River basin based on a long time series (1950–2017) of sediment load data stretching from the headwater to the delta. We find that the sediment loads have decreased progressively throughout the basin at multiple time scales. The sediment loads have decreased by ~96% and ~74% at the outlets of the upper basin and entire basin, respectively, in 2006–2017 compared to 1950–1985. The hydropower dams in the mainstem have become a dominant cause of the reduction, although downstream channel erosion causes moderate sediment load recovery. The basin-scale sediment connectivity has declined as the upper river is progressively dammed, the middle-lower river is leveed and river-lake interplay weakens. The middle-lower river has changed from a slight depositional to a severe erosional environment, from a sediment transport conduit to a new sediment source zone, and from a transport-limited to a supply-limited condition. These low-level sediment loads will likely persist in the future considering the cumulative dam trapping and depleted channel erosion. As a result, substantial hydro-morphological changes have occurred that affect the water supply, flood mitigation, and the aquatic ecosystem. The findings and lessons in this work can shed light on other large river systems subject to intensified human interference.","Changjiang; Sediment load; Sediment starvation; Source-to-sink","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-01-13","","","Coastal Engineering","","",""
"uuid:a99cc4d6-1594-46b6-9afb-282e5f022f00","http://resolver.tudelft.nl/uuid:a99cc4d6-1594-46b6-9afb-282e5f022f00","Investigation on band segregate formation during the electroslag remelting of H13 die steel","Kim, K.H. (TU Delft (OLD) MSE-3; Wuhan University of Science and Technology); Wang, X. J. (Wuhan University of Science and Technology); Li, G. Q. (Wuhan University of Science and Technology); Liu, Y. (Wuhan University of Science and Technology)","","2019","Band segregation has been found in the H13 die steel produced by the electroslag remelting (ESR) technology. Chemical and metallographic studies have been carried out on a one ton ESR ingot of H13 die steel, so as to understand the formation mechanism of the band segregation. The results indicate that the T.O content and S content decreased because of cleanliness improvement of ESR process. Transverse macrosegregation of S content decreased after ESR. The overall removal ratio of the inclusion is around 65.8%. The original complex inclusions would be modified to the CaO•Al2O3 inclusions. Al2O3 and MnS inclusions can be found after ESR. Both of Al2O3 and MnS inclusions were found to be the core of primary carbides. The net like structure in ESR ingot and banded structure in the forged steel were observed. V, Mo, Cr and S are rich in the segregation areas of ESR ingot. Besides, black and white segregation bands can be observed on the forged steel samples after etching. Uneven distribution of carbides rich in V, Mo and Cr was observed in banded structure.","","en","journal article","","","","","","","","","","","(OLD) MSE-3","","",""
"uuid:0c0495e0-74b1-4043-85d0-9e69a2e22962","http://resolver.tudelft.nl/uuid:0c0495e0-74b1-4043-85d0-9e69a2e22962","The Effects of Fiber Length and Volume on Material Properties and Crack Resistance of Basalt Fiber Reinforced Concrete (BFRC)","Wang, Xinzhong (Hunan City University); He, Jun (Changsha University of Science and Technology; Heriot-Watt University); Mosallam, Ayman S. (University of California); Li, Chuanxi (Changsha University of Science and Technology); Xin, H. (TU Delft Steel & Composite Structures)","","2019","Basalt fiber reinforced concrete (BFRC) has been widely utilized in various constructions such as buildings, large industrial floors, and highways, due to its excellent physical and mechanical properties, as well as low production cost. In order to address the influence of basic parameters such as fiber volume fraction (0.05∼0.40%), fiber length (12∼36 mm) of BF, and compressive strength (30, 40, and 50 MPa) of concrete on both physical and mechanical properties of BFRC including compressive strength, tensile and flexural strength, workability, and anti-dry-shrinkage cracking properties, a series of standard material tests were conducted. Experimental results indicated that clumping of fibers may occur at relatively higher fiber volume fraction resulting in mixing and casting problems. Based on experimental values of mechanical properties and anti-dry-shrinkage cracking resistance of BFRC, the reasonable basalt fiber length and fiber volume fractions are identified. The addition of a small amount of short basalt fibers can result in a considerable increase in both compressive strength and modulus of rupture (MoR) of BFRC and that the proposed fiber length and content are 12.0 mm and 0.10%∼0.15%, respectively. As the length of basalt fibers increases, the development of early shrinkage cracks decreases initially and then increases slowly and the optimal fiber length is 18.0 mm. Results of the study also indicated that early shrinkage cracks decrease with the increase of fiber volume fraction, and when the volume fraction of 0.20% is used, no cracks were observed. All the findings of the present study may provide reference for the material proportion design of BFRC.","","en","journal article","","","","","","","","","","","Steel & Composite Structures","","",""
"uuid:ea241a32-56c8-4623-8ea9-762c7022f76a","http://resolver.tudelft.nl/uuid:ea241a32-56c8-4623-8ea9-762c7022f76a","Stress analysis of pressure-assisted sintering for the double-side assembly of power module","Liu, Y. (TU Delft Electronic Components, Technology and Materials; Harbin University of Science and Technology); Zhang, H. (TU Delft Electronic Components, Technology and Materials; Harbin University of Science and Technology); Wang, Lingen (Boschman Technologies); Fan, Xuejun (Lamar University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Sun, Fenglian (Harbin University of Science and Technology)","","2019","Purpose: Crack and stress distribution on dies are key issues for the pressure-assisted sintering bonding of power modules. The purpose of this research is to build a relationship among stress distributions, sintering sequences and sintering pressures during the sintering processes. Design/methodology/approach: Three sintering sequences, S(a), S(b) and S(c), have been designed for the double-side assembly of power module in this paper. Experiments and finite element method (FEM) analysis are conducted to investigate the crack and stress distribution. Findings: The sintering sequence had significant effects on the crack generation in the chips during the sintering process under 30-MPa pressure. The simulation results revealed that the module sintered by S(a) showed lower chip stress than those by the other two sintering sequences under 30 MPa. In contrast, the chip stress is the highest when the sintering sequence follows S(b). The simulation results explained the crack generation and prolongation in the experiments. S(a) was recommended as the best sintering sequence because of the lowest chip stress and highest yield rate. Originality/value: This study investigated the stress distributions of the double-side sintered power modules under different sintering pressures. Based on the results of experiments and FEM analysis, the best sintering sequence design is provided under various sintering pressures.","Double-side assembly; Power chip; Reliability; Sintering","en","journal article","","","","","","Accepted author manuscript","","","","","Electronic Components, Technology and Materials","","",""
"uuid:644b752d-302d-4953-9a5a-78a9d3384b6c","http://resolver.tudelft.nl/uuid:644b752d-302d-4953-9a5a-78a9d3384b6c","Laboratory and numerical investigation of microwave heating properties of asphalt mixture","Wang, H. (TU Delft Pavement Engineering); Zhang, Yue (Rheinisch-Westfälische Technische Hochschule); Zhang, Yi (Chang'an University); Feng, Shuyin (University of Bristol); Lu, Guoyang (Rheinisch-Westfälische Technische Hochschule); Cao, Lintao (Hubei University of Arts and Science)","","2019","Microwave heating is an encouraging heating technology for the maintenance, recycling, and deicing of asphalt pavement. To investigate the microwave heating properties of asphalt mixture, laboratory tests and numerical simulations were done and compared. Two types of Stone Mastic Asphalt (SMA) mixture samples (with basalt aggregates and steel slag aggregates) were heated using a microwave oven for different times. Numerical simulation models of microwave heating of asphalt mixture were developed with finite element software COMSOL Multiphysics. The main thermal and electromagnetic properties of asphalt mixture, served as the model input parameters, were measured through a series of laboratory tests. Both laboratory-measured and numerical simulated surface temperatures were recorded and analyzed. Results show that the replacement of basalt aggregates with steel slag aggregates can significantly increase the microwave heating efficiency of asphalt mixture. Numerical simulation results have a good correlation with laboratory test results. It is feasible to use the developed model coupling electromagnetic waves with heat transfer to simulate the microwave heating process of asphalt mixture.","Asphalt mixture; Dielectric loss; Electromagnetic; Microwave heating; Numerical simulation; Steel slag","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:0c24955e-06a2-40d0-ac2c-3cb5fa25d824","http://resolver.tudelft.nl/uuid:0c24955e-06a2-40d0-ac2c-3cb5fa25d824","Temporal information gathering process for node ranking in time-varying networks","Qu, C. (Shandong University); Zhan, X. (TU Delft Multimedia Computing); Wang, Guanghui (Shandong University); Wu, Jianliang (Shandong University); Zhang, Zi-ke (Hangzhou Normal University; Ministry of Education Hangzhou)","","2019","Many systems are dynamic and time-varying in the real world. Discovering the vital nodes in temporal networks is more challenging than that in static networks. In this study, we proposed a temporal information gathering (TIG) process for temporal networks. The TIG-process, as a node's importance metric, can be used to do the node ranking. As a framework, the TIG-process can be applied to explore the impact of temporal information on the significance of the nodes. The key point of the TIG-process is that nodes' importance relies on the importance of its neighborhood. There are four variables: temporal information gathering depth n, temporal distance matrix D, initial information c, and weighting function f. We observed that the TIG-process can degenerate to classic metrics by a proper combination of these four variables. Furthermore, the fastest arrival distance based TIG-process (fad-tig) is performed optimally in quantifying nodes' efficiency and nodes' spreading influence. Moreover, for the fad-tig process, we can find an optimal gathering depth n that makes the TIG-process perform optimally when n is small.","Social networks; Data mining; Graph theory; Covariance and correlation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-07-01","","","Multimedia Computing","","",""
"uuid:d8ceaf3c-ade5-44c0-9cce-4867e9e442c7","http://resolver.tudelft.nl/uuid:d8ceaf3c-ade5-44c0-9cce-4867e9e442c7","All-in-one improvement toward Li6PS5Br-Based solid electrolytes triggered by compositional tune","Zhang, Zhixia (Yanshan University); Zhang, Long (Yanshan University); Yan, Xinlin (Technische Universität Wien); Wang, Hongqiang (Hebei University); Liu, Yanyan (Yanshan University); Yu, C. (TU Delft RST/Storage of Electrochemical Energy); Cao, Xiaoting (Yanshan University); van Eijck, L. (TU Delft RST/Neutron and Positron Methods in Materials); Wen, Bin (Yanshan University)","","2019","Sulfide solid electrolytes possess high ionic conductivity and moderate dendrite suppression capability, but rather poor compatibility against oxide cathodes and metallic Li. Here, we report O-doped Li6PS5Br as solid electrolyte synthesized by a facile solid-state sintering. Different from other O-incorporated sulfides, the O atoms in Li6PS5-xOxBr prefer to substitute the S atoms at free S2− sites rather than those at the PS4 tetrahedra. Remarkably, without deteriorating the ionic conductivity, this inorganic solid electrolyte with O doping exhibits comprehensively enhanced properties including excellent dendrite suppression capability, superior electrochemical and chemical stability against Li metal as well as high voltage oxide cathodes, and good air stability. Li(Ni0.8Co0.1Mn0.1)O2 and LiCoO2-based all-solid-state batteries with Li6PS4.7O0.3Br electrolyte deliver high specific capacity, superior rate capability, and outstanding cycling stability accompanied with low interfacial resistivity. This type of inorganic solid electrolytes is promising for all-solid-state batteries with high energy density.","All-solid-state batteries; Argyrodites; Interfacial stability; Li dendrite suppression; Solid electrolytes","en","journal article","","","","","","","","2020-11-13","","","RST/Storage of Electrochemical Energy","","",""
"uuid:2e2cd06e-41e7-4e5e-bc2a-81b8c2389b5c","http://resolver.tudelft.nl/uuid:2e2cd06e-41e7-4e5e-bc2a-81b8c2389b5c","Optimization models for high-speed train unit routing problems","Wang, Ying (Beijing Jiaotong University); Gao, Yuan (Beijing Jiaotong University); Yu, Xiaoyuan (Beijing Jiaotong University); Hansen, I.A. (TU Delft Transport and Planning); Miao, Jianrui (Beijing Jiaotong University)","","2019","Train unit routing problem determines the number of train units needed to carry out involved trips, which is a significant part of railway operation cost. In this paper, we focus on high-speed train unit routing problems, in which maintenance resource constraints both on time and distance are taken into account. Based on a connection network, this paper first proposes a general train unit routing model. Then, the general model is specialized to meet the circulation and maintenance conditions of high-speed train units in China, which is based on a special connection network with a two-day time horizon. A strategy is proposed to reduce the scale of the connection network, which improves the model's solvability. Furthermore, an extension on multi-depot train unit routing problem is discussed. Finally, numerical experiments based on the real data of Chinese high-speed railway are carried out to verify the effectiveness and efficiency of the proposed mode and method.","High-speed railway; Integer programming; Maintenance; Train unit routing problem","en","journal article","","","","","","Accepted Author Manuscript","","2021-06-30","","","Transport and Planning","","",""
"uuid:6db7d744-e1e7-4a7a-99da-dd6c00db5c7a","http://resolver.tudelft.nl/uuid:6db7d744-e1e7-4a7a-99da-dd6c00db5c7a","Stratification of nitrifier guilds in granular sludge in relation to nitritation","Soler Jofra, A. (TU Delft BT/Environmental Biotechnology); Wang, R. (TU Delft BT/Environmental Biotechnology; Zhejiang University); Kleerebezem, R. (TU Delft BT/Environmental Biotechnology); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology); Pérez, Julio (TU Delft BT/Environmental Biotechnology; Universitat Autònoma de Barcelona)","","2019","A lab-scale partial nitritation granular sludge air-lift reactor was operated in continuous mode treating low strength synthetic medium (influent ca. 50 mg-N-NH4 +/L). Granules were initially stratified with AOB in the external shell and NOB in the inner core at 20 °C. Once temperature was decreased progressively from 20 °C to 15 °C, nitrate production was initially observed during several weeks. However, by maintaining relatively high ammonium concentrations in the liquid (ca. 28 mg-N-NH4 +/L), effluent nitrate concentrations in the reactor decreased in time and process performance was recovered. Batch tests were performed in the reactor at different conditions. To understand the experimental results an existing one-dimensional biofilm model was used to simulate batch tests and theoretically assess the impact of stratification, dissolved oxygen (DO) and short-term effects of temperature on time course concentrations of ammonium, nitrite and nitrate. This theoretical assessment served to develop an experimental methodology for the evaluation of in-situ batch tests in the partial nitritation reactor. These batch tests proved to be a powerful tool to easily monitor the extent of stratification of nitrifier guilds in granular sludge and to determine the required bulk ammonium concentration to minimize nitrite oxidation. When nitrifier guilds were stratified in the granular sludge, a higher bulk ammonium concentration was required to efficiently repress NOB at lower temperature (ca. 19 versus 7 mg-N-NH4 +/L at 15 and 20 °C, respectively).","Biofilm; Nitrate-oxidizing bacteria repression; Partial nitrification; Residual ammonium concentration; Temperature","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:96b7d29a-6a48-4e9b-bde0-852dc39abdc1","http://resolver.tudelft.nl/uuid:96b7d29a-6a48-4e9b-bde0-852dc39abdc1","Air bubbles in calcium caseinate fibrous material enhances anisotropy","Wang, Zhaojun (Wageningen University & Research); Tian, B. (TU Delft RST/Neutron and Positron Methods in Materials); Boom, Remko (Wageningen University & Research); van der Goot, Atze Jan (Wageningen University & Research)","","2019","Dense calcium caseinate dispersions can be transformed into hierarchically fibrous structures by shear deformation. This transformation can be attributed to the intrinsic properties of calcium caseinate. Depending on the dispersion preparation method, a certain amount of air gets entrapped in the sheared protein matrix. Although anisotropy is obtained in the absence of entrapped air, the fibrous appearance and mechanical anisotropy of the calcium caseinate materials are more pronounced with dispersed air present. The presence of air induces the protein fibers to be arranged in microscale bundles, and the fracture strain and stress in the parallel direction are larger compared with the material without air. The effects can be understood from the alignment of the fibers in the parallel direction, providing strain energy dissipation. This study shows that creation of anisotropy is the result of interactions between multiple phases.","Air bubble; Anisotropy; Fibrous material; Mechanical property; Microstructure","en","journal article","","","","","","","","","","","RST/Neutron and Positron Methods in Materials","","",""
"uuid:9cec4a81-9652-4f6d-ba45-4235558eccf9","http://resolver.tudelft.nl/uuid:9cec4a81-9652-4f6d-ba45-4235558eccf9","Precision analysis of troposphere sensing using GPS single-frequency signals","Wang, K. (Curtin University); Khodabandeh, A. (Curtin University; University of Melbourne); Teunissen, P.J.G. (TU Delft Mathematical Geodesy and Positioning; Curtin University)","","2019","Various studies have been performed to investigate the accuracy of troposphere zenith wet delays (ZWDs) determined from GPS. Most of these studies use dual-frequency GPS data of large-scale networks with long baselines to determine the absolute ZWDs. For small-scale networks the estimability of the absolute ZWDs deteriorates due to high correlation between the solutions of the ZWDs and satellite-specific parameters as satellite clocks. However, as relative ZWDs (rZWDs) can always be estimated, irrespective of the size of the network, it is of interest to understand how the large-scale network rZWD-performance of dual-frequency GPS using an ionosphere-float model compares to the small-scale network rZWD-performance of single-frequency GPS using an ionosphere-weighted model. In this contribution such an analysis is performed using undifferenced and uncombined network parametrization modelling. In this context we demonstrate the ionosphere weighted constraints, which allows the determination of the rZWDs independent from signals on the second frequency. Based on an analysis of both simulated and real data, it is found that under quiet ionosphere conditions, the accuracy of the single-frequency determined rZWDs in the ionosphere-weighted network is comparable to that of the large-scale dual-frequency network without ionospheric constraints. Making use of the real data from two baselines of 15 days, it was found that the absolute differences of the rZWDs applying the two strategies are within 1 cm in over 90% and 95% of the time for ambiguity-float and -fixed cases, respectively.","Dual-frequency; Global Positioning System (GPS); Ionosphere; Single-frequency; Troposphere; Zenith Wet Delay (ZWD)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","","","","Mathematical Geodesy and Positioning","","",""
"uuid:f58aa038-8395-454c-b6e9-cadc05120201","http://resolver.tudelft.nl/uuid:f58aa038-8395-454c-b6e9-cadc05120201","Supercritical water oxidation of quinoline with moderate preheat temperature and initial concentration","Ren, M. (TU Delft Fluid Mechanics; Xian Jiaotong University); Wang, Shuzhong (Xian Jiaotong University); Yang, Chuang (Xian Jiaotong University); Xu, Haitao (Xian Jiaotong University); Guo, Yang (Xian Jiaotong University); Roekaerts, D.J.E.M. (TU Delft Fluid Mechanics)","","2019","This work reports an experimental study on supercritical water oxidation of quinoline. Moderate preheat temperature (420 °C–510 °C) and initial concentration (1 wt%–10 wt%) are selected to address the possibility of utilizing the heat released during the reaction, in order to realize high conversion rate at relatively low preheat temperature. The effects of temperature, residence time, oxidation ratio, pressure and concentration are analyzed. The results show that considerable conversion can happen at relatively low preheat temperature, while increase in temperature will significantly promote the complete conversion. The yield of carbon dioxide increases with the residence time but there is an upper limit due to the stronger dependence on oxidizer concentration, for which an estimated reaction order is 1.90. When the quinoline concentration is larger than 8 wt%, clear exothermic peaks with temperature rise about 100 °C are detected. These exothermic peaks can be interpreted as a sign of ignition interrupted by the heat loss to the surrounding salt bath. An analogy is made between the start temperatures of these exothermic peaks and the ignition temperatures reported in methanol and isopropanol hydrothermal flame research. We conclude that quinoline solutions can be ignited without co-fuels, at comparable ignition temperature as methanol and isopropanol around 450 °C.","Heat release; Ignition; Initial concentration; Preheat temperature; Quinoline; Supercritical water oxidation (SCWO)","en","journal article","","","","","","Accepted Author Manuscript","","2020-09-29","","","Fluid Mechanics","","",""
"uuid:083af444-2039-4595-bc5a-7917090c4dd9","http://resolver.tudelft.nl/uuid:083af444-2039-4595-bc5a-7917090c4dd9","Influence of surface pretreatment on phosphate conversion coating on AZ91 Mg alloy","Zhang, Chunyan (Harbin Engineering University; Chinese Academy of Sciences); Liu, Bin (Harbin Engineering University); Yu, Baoxing (Chinese Academy of Sciences); Lu, Xiaopeng (Northeastern University); Wei, Yong (Harbin Engineering University); Zhang, Tao (Harbin Engineering University; Chinese Academy of Sciences; Northeastern University); Mol, J.M.C. (TU Delft (OLD) MSE-6); Wang, Fuhui (Northeastern University)","","2019","Surface pretreatment is generally applied before application of protective coatings on Mg alloys, which influences surface microstructure and electrochemical activity of the substrate and has an effect on the coating properties. The effect of various pretreatment processes (sand-blasting, grinding and polishing) on the microstructure and corrosion protection performance of phosphate conversion coating (PCC) on AZ91D Mg alloy was investigated in the present study. Sand-blasting cleaning significantly increases the surface roughness and electrochemical activity of the substrate, leading to formation of a porous PCC with inferior corrosion protection performance. In the case of ground/polished Mg alloy, the uniformity and corrosion resistance of the resultant conversion coating are mainly related to the surface roughness. Relatively low surface roughness of the substrate facilitates formation of a corrosion protective PCC.","Corrosion protection; Mg alloy; Phosphate conversion coating; Surface pretreatment","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-06-22","","","(OLD) MSE-6","","",""
"uuid:b50798d7-2f8a-4aeb-8911-72d5219990bc","http://resolver.tudelft.nl/uuid:b50798d7-2f8a-4aeb-8911-72d5219990bc","Carbon deposition in porous nickel/yttria-stabilized zirconia anode under methane atmosphere","Chen, Z. (TU Delft (OLD) MSE-3; University of Science and Technology Beijing); Wang, Li jun (University of Science and Technology Beijing); Du, Xiao jia (Suzhou Huatsing Jingkun New Energy Technology Co.); Sun, Zai hong (Suzhou Huatsing Jingkun New Energy Technology Co.); Li, Fu shen (University of Science and Technology Beijing); Chou, Kuo Chih (University of Science and Technology Beijing)","","2019","A commercial solid oxide fuel cell with a Ni/YSZ anode was characterized under a pure methane atmosphere. The amount of deposited carbon increased with an increase in temperature but decreased when the temperature exceeded 700°C. The reactivity of carbon decreased with increasing deposition temperature. Filamentous carbon was deposited from 400 to 600°C, whereas flake carbon was deposited at 700 and 800°C. With increasing temperature, the intensity ratio of the D band over the sum of the G and D bands was constant at the beginning and then decreased with the transformation of the carbon morphology. The crystallite size increased from 2.9 to 13 nm with increasing temperature. The results also indicated that the structure of the deposited carbon was better ordered with increasing deposition temperature. In comparison with pure Ni powders, the interaction between the YSZ substrate and Ni particles could not only modify the carbon deposition kinetics but also reduce the temperature effect on the structure and reactivity variation of carbon.","anode; coking; hydrocarbon fuel; Raman spectrum; solid oxide fuel cell","en","journal article","","","","","","Accepted Author Manuscript","","2020-03-08","","","(OLD) MSE-3","","",""
"uuid:58b45c36-1aaa-4d36-9cbf-7f705734621f","http://resolver.tudelft.nl/uuid:58b45c36-1aaa-4d36-9cbf-7f705734621f","Assessment of numerical methods for fully resolved simulations of particle-laden turbulent flows","Brändle de Motta, J. C. (Université de Rouen; Université de Toulouse); Simões Costa, P. (TU Delft Fluid Mechanics; KTH Royal Institute of Technology); Derksen, J. J. (University of Aberdeen); Peng, C. (University of Delaware); Wang, L. P. (University of Delaware; Southern University of Science and Technology); Breugem, W.P. (TU Delft Multi Phase Systems); Estivalezes, J. L. (ONERA Centre de Toulouse; Université de Toulouse); Vincent, S. (Université Paris-Est); Climent, E. (Université de Toulouse); Fede, P. (Université de Toulouse); Barbaresco, P. (Université de Toulouse); Renon, N. (Université de Toulouse)","","2019","During the last decade, many approaches for resolved-particle simulation (RPS) have been developed for numerical studies of finite-size particle-laden turbulent flows. In this paper, three RPS approaches are compared for a particle-laden decaying turbulence case. These methods are, the Volume-of-Fluid Lagrangian method, based on the viscosity penalty method (VoF-Lag); a direct forcing Immersed Boundary Method, based on a regularized delta function approach for the fluid/solid coupling (IBM); and the Bounce Back scheme developed for Lattice Boltzmann method (LBM-BB). The physics and the numerical performances of the methods are analyzed. Modulation of turbulence is observed for all the methods, with a faster decay of turbulent kinetic energy compared to the single-phase case. Lagrangian particle statistics, such as the velocity probability density function and the velocity autocorrelation function, show minor differences among the three methods. However, major differences between the codes are observed in the evolution of the particle kinetic energy. These differences are related to the treatment of the initial condition when the particles are inserted in an initially single-phase turbulence. The averaged particle/fluid slip velocity is also analyzed, showing similar behavior as compared to the results referred in the literature. The computational performances of the different methods differ significantly. The VoF-Lag method appears to be computationally most expensive. Indeed, this method is not adapted to turbulent cases. The IBM and LBM-BB implementations show very good scaling.","Direct numerical simulations; Finite-size particles; Particle-laden flows; Turbulence","en","journal article","","","","","","Accepted Author Manuscript","","2019-10-30","","","Fluid Mechanics","","",""
"uuid:b09bb5e3-27a5-4871-86a4-74fe108b2c3d","http://resolver.tudelft.nl/uuid:b09bb5e3-27a5-4871-86a4-74fe108b2c3d","Fuzzy adaptive DSC design for an extended class of MIMO pure-feedback non-affine nonlinear systems in the presence of input constraints","Wang, Ning (Air Force Engineering University); Wang, Ying (Air Force Engineering University); Lv, Maolong (TU Delft Team Bart De Schutter; Air Force Engineering University)","","2019","A novel adaptive fuzzy dynamic surface control (DSC) scheme is for the first time constructed for a larger class of (multi-input multi-output) MIMO non-affine pure-feedback systems in the presence of input saturation nonlinearity. First of all, the restrictive differentiability assumption on non-affine functions has been canceled after using the piecewise functions to reconstruct the model for non-affine nonlinear functions. Then, a novel auxiliary system with bounded compensation term is firstly introduced to deal with input saturation, and the dynamic system employed in this work designs a bounded compensation term of tangent function. Thus, we successfully relax the strictly bounded assumption of the dynamic system. Additionally, the fuzzy logic systems (FLSs) are used to approximate unknown continuous systems functions, and the minimal learning parameter (MLP) technique is exploited to simplify control design and reduce the number of adaptive parameters. Finally, two simulation examples with input saturation are given to validate the effectiveness of the developed method.","","en","journal article","","","","","","","","","","","Team Bart De Schutter","","",""
"uuid:807820d2-0bbe-441f-b787-b943187d1509","http://resolver.tudelft.nl/uuid:807820d2-0bbe-441f-b787-b943187d1509","Comparative performance of upflow anaerobic sludge blanket reactor and anaerobic membrane bioreactor treating phenolic wastewater: Overcoming high salinity","Muñoz Sierra, Julian (TU Delft Sanitary Engineering); Oosterkamp, M.J. (TU Delft Sanitary Engineering); Wang, W. (TU Delft Sanitary Engineering; Hefei University of Technology); Spanjers, H. (TU Delft Sanitary Engineering); van Lier, J.B. (TU Delft Sanitary Engineering)","","2019","Anaerobic membrane bioreactors (AnMBRs) offer an attractive option for treating industrial wastewaters under extreme conditions that might hamper granulation, biomass retention and reduce biological activity. This study assesses the long-term performance of an upflow anaerobic sludge blanket reactor (UASB) and an AnMBR treating highly saline phenolic wastewater. Analysis of bioreactor conversion, biomass characteristics and microbial community dynamics under increasing sodium and phenol concentrations is presented. The results demonstrated that compared to the UASB, the AnMBR process exhibited higher stability, likely due to its enhanced biomass retention. The AnMBR retained specialized microorganisms under increasing influent concentrations of phenol up to 5 gPh·L−1 and salinity up to 26 gNa+·L−1. In contrast, when the UASB reached this high influent phenol and high sodium concentration, deflocculation of biomass, apparently due to calcium leaching, was observed leading to a severe conversion capacity loss. Microbial community dynamics showed higher species evenness in the AnMBR compared to the UASB, leading to a higher methanogenic ability to respond to disturbances such as high phenol and sodium concentration increases. These findings highlighted the promising features of AnMBR technology, in widening the application potentials of high-rate anaerobic wastewater treatment and overcoming specific challenges in the treatment of chemical wastewater streams under extreme environmental conditions such as high salinity.","AnMBR; Deflocculation; Microbial dynamics; Phenol; Salinity; UASB","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:65a5f5d2-a864-49b0-b9b2-190f8f7b545e","http://resolver.tudelft.nl/uuid:65a5f5d2-a864-49b0-b9b2-190f8f7b545e","A numerical Bayesian-calibrated characterization method for multiscale prepreg preforming simulations with tension-shear coupling","Zhang, Weizhao (Northwestern University); Bostanabad, Ramin (Northwestern University); Liang, Biao (Northwestern University); Su, Xuming (Ford Motor Company); Zeng, Danielle (Ford Motor Company); Bessa, M.A. (TU Delft (OLD) MSE-5); Wang, Yanchao (Tongji University); Chen, Wei (Northwestern University); Cao, Jian (Northwestern University)","","2019","Carbon fiber reinforced plastics (CFRPs) are attracting growing attention in industry because of their enhanced properties. Preforming of thermoset carbon fiber prepregs is one of the most common production techniques of CFRPs. To simulate preforming, several computational methods have been developed. Most of these methods, however, obtain the material properties directly from experiments such as uniaxial tension and bias-extension where the coupling effect between tension and shear is not considered. Neglecting this coupling effect deteriorates the prediction accuracy of simulations. To address this issue, we develop a Bayesian model calibration and material characterization approach in a multiscale finite element preforming simulation framework that utilizes mesoscopic representative volume element (RVE) to account for the tension-shear coupling. A new geometric modeling technique is first proposed to generate the RVE corresponding to the close-packed uncured prepreg. This RVE model is then calibrated with a modular Bayesian approach to estimate the yarn properties, test its potential biases against the experiments, and fit a stress emulator. The predictive capability of this multiscale approach is further demonstrated by employing the stress emulator in the macroscale preforming simulation which shows that this approach can provide accurate predictions.","Bayesian calibration; Gaussian processes; Multiscale simulations; Preforming; Prepreg","en","journal article","","","","","","Accepted Author Manuscript","","2019-11-22","","","(OLD) MSE-5","","",""
"uuid:9e4a74f1-d072-4189-9cac-addd480be280","http://resolver.tudelft.nl/uuid:9e4a74f1-d072-4189-9cac-addd480be280","Abundant grain boundaries activate highly efficient lithium ion transportation in high rate Li4Ti5O12 compact microspheres","Ma, Jiaming (Tsinghua University); Wei, Yinping (Tsinghua University); Gan, Lin (Tsinghua University); Wang, C. (TU Delft RST/Fundamental Aspects of Materials and Energy; TU Delft RST/Storage of Electrochemical Energy); Xia, Heyi (Tsinghua University); Lv, Wei (Tsinghua University); Li, Jia (Tsinghua University); Li, Baohua (Tsinghua University); Yang, Quan Hong (Tianjin University); Kang, Feiyu (Tsinghua University); He, Yan Bing (Tsinghua University)","","2019","It is a huge challenge for high-tap-density electrodes to achieve high volumetric energy density but without compromising the ionic transportation. Herein, we prepared compact Li4Ti5O12 (LTO) microspheres consisting of densely packed primary nanoparticles. The real space distribution of lithium ions inside the compact LTO was revealed by using scanning transmission electron microscopy with electron energy loss spectroscopy (STEM-EELS) to identify the function of grain boundaries for lithium ion transportation during lithiation. The as-prepared LTO microspheres possess a high tap density (1.23 g cm-3) and an ultra-small specific surface area (2.40 m2 g-1). Impressively, the compact LTO microspheres present excellent electrochemical performance. At high rates of 5C, 10C and 20C, the LTO microspheres show a specific capacity of 146.6, 138.2 and 111 mA h g-1, respectively. The capacity retention remains at 97.8% at 5C after 500 cycles. The STEM-EELS results indicate that the lithiation reaction of LTO is firstly initiated at grain boundaries during the high rate lithiation process and then diffuses to the bulk area. The abundant grain boundaries in compact LTO microspheres can form a highly efficient conductive network to preferentially transport the ions, which contributes to high volumetric and gravimetric energy density simultaneously.","","en","journal article","","","","","","Accepted Author Manuscript","","2019-12-05","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:35d0df5a-e06f-4609-8003-3492888eef52","http://resolver.tudelft.nl/uuid:35d0df5a-e06f-4609-8003-3492888eef52","Understanding the role of air and protein phase on mechanical anisotropy of calcium caseinate fibers","Wang, Zhaojun (Wageningen University & Research); Tian, B. (TU Delft RST/Neutron and Positron Methods in Materials); Boom, Remko (Wageningen University & Research); van der Goot, Atze Jan (Wageningen University & Research)","","2019","Calcium caseinate dispersions can be transformed into anisotropic, fibrous materials using the concept of shear-induced structuring. The aim of this study is to further investigate the relative importance of air bubbles and protein on the mechanical anisotropy of calcium caseinate material. In this study, the effect of air on mechanical anisotropy of these fibrous materials was described with a load-bearing model, with the void fraction, and the bubble length and width as input parameters. The anisotropy of the protein phase was estimated using materials obtained from deaerated dispersions after shearing at different shear rates. We concluded that the deformation of air bubbles can only partly explain the mechanical anisotropy; the anisotropy of the protein phase is more important. Based on all results, we further concluded that the anisotropy of the protein phase was affected by the air bubbles present during the structuring process. This effect was explained by locally higher shear rate in the protein matrix during the structuring process.","Air bubbles; Anisotropy; Calcium caseinate; Fibers; Mechanical property; Shear","en","journal article","","","","","","","","","","","RST/Neutron and Positron Methods in Materials","","",""
"uuid:a738f885-102e-4811-855e-a4fd679ae75e","http://resolver.tudelft.nl/uuid:a738f885-102e-4811-855e-a4fd679ae75e","Using advanced adaptive cruise control systems to reduce congestion at sags: An evaluation based on microscopic traffic simulation","Goni Ros, B. (TU Delft Transport and Planning); Schakel, W.J. (TU Delft Transport and Planning); Papacharalampous, Alexandros E. (AETHON Engineering Consultants); Wang, M. (TU Delft Transport and Planning); Knoop, V.L. (TU Delft Transport and Planning); Sakata, Ichiro (Toyota Motor Europe); van Arem, B. (TU Delft Transport and Planning); Hoogendoorn, S.P. (TU Delft Transport and Planning)","","2019","Sags are roadway sections along which the gradient increases gradually in the direction of traffic. Sags are generally bottlenecks in freeway networks. Previous research suggests that traffic management measures using advanced Adaptive Cruise Control (ACC) systems could reduce congestion on freeways, but little is known about their potential effectiveness at sags. This article evaluates the effectiveness of a basic ACC system (B-ACC) and two advanced ACC systems – Traffic State-Adaptive ACC (TSA-ACC) and Cooperative ACC (C-ACC) – in mitigating congestion at sags. TSA-ACC adapts the ACC parameters to the macroscopic traffic state estimated by the vehicle itself. C-ACC uses information of other vehicles in the surroundings to adjust its accelerations. Results are obtained using microscopic traffic simulations with different penetration rates. They show that, under high-demand conditions, congestion decreases with increasing percentage of vehicles equipped with B-ACC. With high penetration rates (75% and above), traffic no longer becomes congested at the sag. Moreover, the results show that TSA-ACC and C-ACC reduce congestion more than B-ACC, mainly because they increase the queue discharge capacity of the sag. The two advanced ACC systems prevent the formation of congestion at the sag at lower penetration rates than B-ACC. TSA-ACC is the most effective system. C-ACC is only more effective than B-ACC in scenarios with 20% penetration rate or higher; below that, connectivity between equipped vehicles is too low. Our findings show the potential of using advanced ACC systems to mitigate congestion at sags and indicate some challenges of this traffic management approach.","Adaptive Cruise Control; Freeway capacity; Microscopic traffic simulation; Sag vertical curve; Traffic management","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-09-27","","Transport and Planning","Transport and Planning","","",""
"uuid:2837149c-3d1c-4ff7-b573-675e3a7bf91e","http://resolver.tudelft.nl/uuid:2837149c-3d1c-4ff7-b573-675e3a7bf91e","Time-domain oversampled orthogonal signal-division multiplexing underwater acoustic communications","Han, J. (Northwestern Polytechnical University); Wang, Yujie (Northwestern Polytechnical University); Zhang, Lingling (Northwestern Polytechnical University); Leus, G.J.T. (TU Delft Signal Processing Systems)","","2019","Orthogonal signal-division multiplexing (OSDM) is a recently emerging modulation scheme which, compared to conventional orthogonal frequency-division multiplexing, can effectively lower the peak-to-average power ratio and introduce intra-vector frequency diversity. In this paper, a time-domain oversampled OSDM system for underwater acoustic (UWA) communications is designed, where each OSDM vector is equivalently transmitted over multiple virtual channels, and thus an enhanced frequency diversity gain can be achieved. Moreover, at the receiver, zero vectors and frequency-shifted Chu sequences are used for Doppler compensation and channel estimation, respectively, while low-complexity per-vector equalization is performed based on the composite channel matrix factorization. Finally, the performance of the proposed OSDM system is evaluated through both numerical simulations and a short-range field experiment, and its effectiveness over time-varying UWA channels is confirmed.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-07-22","","","Signal Processing Systems","","",""
"uuid:cd374afc-9df4-435e-90c5-ec2cd3911418","http://resolver.tudelft.nl/uuid:cd374afc-9df4-435e-90c5-ec2cd3911418","Forecasting pedestrian movements using recurrent neural networks: An application of crowd monitoring data","Duives, D.C. (TU Delft Transport and Planning); Wang, Guangxing (University of Queensland); Kim, Jiwon (University of Queensland)","","2019","Currently, effective crowd management based on the information provided by crowd monitoring systems is difficult as this information comes in at the moment adverse crowd movements are already occurring. Up to this moment, very little forecasting techniques have been developed that predict crowd flows a longer time period ahead. Moreover, most contemporary state estimation methods apply demanding pre-processing steps, such as map-matching. The objective of this paper is to design, train and benchmark a data-driven procedure to forecast crowd movements, which can in real-time predict crowd movement. This procedure entails two steps. The first step comprises of a cell sequence derivation method that allows the representation of spatially continuous GPS traces in terms of discrete cell sequences. The second step entails the training of a Recursive Neural Network (RNN) with a Gated Recurrent Unit (GRU) and six benchmark models to forecast the next location of pedestrians. The RNN-GRU is found to outperform the other tested models. Some additional tests of the ability of the RNN-GRU to forecast illustrate that the RNN-GRU preserves its predictive power when a limited amount of data is used from the first few hours of a multi-day event and temporal information is incorporated in the cell sequences.","Deep learning algorithms; Forecasting; GPS trajectories; Pedestrian crowd movements; Recursive Neural Network (RNN) with Gated Recurrent Unit (GRU)","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:23187ae3-8898-4b2a-8ed9-ca221b693adc","http://resolver.tudelft.nl/uuid:23187ae3-8898-4b2a-8ed9-ca221b693adc","Ammonia absorption in ionic liquids-based mixtures in plate heat exchangers studied by a semi-empirical heat and mass transfer framework","Wang, M. (TU Delft Engineering Thermodynamics); He, Lijuan (Inner Mongolia Normal University China); Infante Ferreira, C.A. (TU Delft Engineering Thermodynamics)","","2019","Unfavorable transport properties have always been pointed out as the key factors that hinder the application of ammonia/ionic liquids (NH 3 /ILs) in absorption cycles, while heat and mass transfer of these new fluids in components have been rarely reported. In this study, a corrugated plate heat exchanger is selected as the geometry for exploring the absorption of NH 3 in the proposed NH 3 /ILs working fluids. The process is studied making use of a semi-empirical framework: experimental data is needed to determine unknown information of heat and mass transfer, and a numerical model is developed making use of frequently applied theories. In addition, relevant transport properties of the NH 3 /ILs working fluids are modeled based on collected experimental data. The proposed model is used to study the heat and mass transfer performance during the absorption of NH 3 vapor into NH 3 /ILs fluids. Distribution of local parameters and overall heat and mass transfer characteristics are obtained. The performance of absorption of NH 3 into different working fluids is investigated as well. The overall heat transfer coefficient is found around 1.4 kW/(m 2 ·K) for the most promising working fluid NH 3 /[emim][SCN].","Absorption; Ammonia; Heat transfer; Ionic liquid; Lithium nitrate; Mass transfer; Plate heat exchanger","en","journal article","","","","","","","","","","","Engineering Thermodynamics","","",""
"uuid:8421ded7-6354-4300-b3dd-ca76a1fe9141","http://resolver.tudelft.nl/uuid:8421ded7-6354-4300-b3dd-ca76a1fe9141","Information diffusion backbones in temporal networks","Zhan, X. (TU Delft Multimedia Computing); Hanjalic, A. (TU Delft Intelligent Systems); Wang, H. (TU Delft Multimedia Computing)","","2019","Progress has been made in understanding how temporal network features affect the percentage of nodes reached by an information diffusion process. In this work, we explore further: which node pairs are likely to contribute to the actual diffusion of information, i.e., appear in a diffusion trajectory? How is this likelihood related to the local temporal connection features of the node pair? Such deep understanding of the role of node pairs is crucial to tackle challenging optimization problems such as which kind of node pairs or temporal contacts should be stimulated in order to maximize the prevalence of information spreading. We start by using Susceptible-Infected (SI) model, in which an infected (information possessing) node could spread the information to a susceptible node with a given infection probability β whenever a contact happens between the two nodes, as the information diffusion process. We consider a large number of real-world temporal networks. First, we propose the construction of an information diffusion backbone G B (β) for a SI spreading process with an infection probability β on a temporal network. The backbone is a weighted network where the weight of each node pair indicates how likely the node pair appears in a diffusion trajectory starting from an arbitrary node. Second, we investigate the relation between the backbones with different infection probabilities on a temporal network. We find that the backbone topology obtained for low and high infection probabilities approach the backbone G B (β → 0) and G B (β = 1), respectively. The backbone G B (β → 0) equals the integrated weighted network, where the weight of a node pair counts the total number of contacts in between. Finally, we explore node pairs with what local connection features tend to appear in G B (β = 1), thus actually contribute to the global information diffusion. We discover that a local connection feature among many other features we proposed, could well identify the (high-weight) links in G B (β = 1). This local feature encodes the time that each contact occurs, pointing out the importance of temporal features in determining the role of node pairs in a dynamic process.","OA-Fund TU Delft","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","","","Intelligent Systems","Multimedia Computing","","",""
"uuid:6ac32251-bf6d-4261-b70e-2b3f23b285a8","http://resolver.tudelft.nl/uuid:6ac32251-bf6d-4261-b70e-2b3f23b285a8","Design and characterization of zero magnetic field chambers for high efficiency neutron polarization transport","Dadisman, Ryan (Oak Ridge National Laboratory); Shen, Jiazhou (Indiana University - Purdue University); Feng, Hao (Indiana University - Purdue University); Crow, Lowell (Oak Ridge National Laboratory); Jiang, Chenyang (Oak Ridge National Laboratory); Wang, Tianhao (Oak Ridge National Laboratory); Zhang, Yuxuan (Oak Ridge National Laboratory); Bilheux, Hassina (Oak Ridge National Laboratory); Parnell, S.R. (TU Delft RID/TS/Instrumenten groep)","","2019","Several methods of polarized neutron scattering call for a zero magnetic field (ZF) region to reduce magnetic field integral aberrations while preserving the neutron polarization. Though the design for large angle neutron scattering has been presented in various places, the design characterization and tuning has not been discussed before. In this report, the tuning procedure will be discussed with both neutron polarization transport method and utilization of fluxgate magnetometers. As a tuning procedure, polarized neutrons are sensitive to any local field distortions along all trajectories within the beam, but the process is slow. With fluxgates, the entire beam region cannot be accessed simultaneously, but very fast and precise measurements can be made in accessible regions of interest. Consequently, we would like to benchmark the usage of fluxgates as a fast tuning probe compared with polarization measurements made with neutrons. Polarization transport results for tuned ZF chambers, up to 2.25 m in length, are presented.","Large-angle neutron scattering; Larmor labeling; Magnetic Wollaston prisms; Polarization transport; Small-angle neutron scattering; Zero magnetic field","en","journal article","","","","","","Accepted Author Manuscript","","2021-06-18","","","RID/TS/Instrumenten groep","","",""
"uuid:7c16adfa-1f1f-4b6e-9210-a4dcf9ad7b55","http://resolver.tudelft.nl/uuid:7c16adfa-1f1f-4b6e-9210-a4dcf9ad7b55","Tweeting with Sunlight: Encoding Data on Mobile Objects","Bloom, Rens (AMS Institute); Zuniga, Marco (TU Delft Embedded Systems; AMS Institute); Wang, Q. (Katholieke Universiteit Leuven); Giustiniano, Domenico (IMDEA Networks Institute)","","2019","We analyze and optimize the performance of a new type of channel that exploits sunlight for wireless communication. Recent advances on visible light backscatter have shown that if mobile objects attach distinctive reflective patterns to their surfaces, simple photosensors deployed in our environments can decode the reflected light signals. Although the vision is promising, only initial feasibility studies have been performed so far. There is no analysis on how much information this channel can transmit or how reliable the links are. Achieving this vision is a complex endeavour because we have no control over (i) the sun or clouds, which determine the amount and direction of light intensity, and (ii) the mobile object, which determines the modulated reflection of sunlight. We investigate the impact of the surrounding light intensity and physical properties of the object (reflective materials, size and speed) to design a communication system that optimizes the encoding and decoding of information with sunlight. Our experimental evaluation, performed with a car moving on a regular street, shows that our analysis leads to significant improvements across many dimensions. Compared to the state of the art, we can encode seven times more information, and decode this information reliably from an object moving three times faster (53km/h) at a range that is four times longer (4m) and with three times lower light intensity (cloudy day).","","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-08-17","","","Embedded Systems","","",""
"uuid:55c3facc-0897-4ab5-9857-1664d0d4a69e","http://resolver.tudelft.nl/uuid:55c3facc-0897-4ab5-9857-1664d0d4a69e","Numerical investigation of rubber swelling in bitumen","Wang, H. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Apostolidis, P. (TU Delft Pavement Engineering); Erkens, S. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Khalifa University of Science and Technology)","","2019","Crumb rubber modified bitumen (CRMB) has been utilized in the asphalt paving industry for decades due to its various benefits. The main mechanisms of bitumen-crumb rubber interaction include rubber particle swelling and chemical degradation. Crumb rubber modifier (CRM) swelling plays a dominant role in controlling the property development of CRMB during the traditional interaction process. To have a better understanding of the swelling behavior of rubber in bitumen, this study developed a finite element model capable to simulate the multiphysics swelling phenomenon consisting of mass diffusion and volume expansion. The effects of various factors including material characteristics and process conditions on the rubber swelling in bitumen were investigated. The results indicate that the coupled diffusion-expansion model can predict the swelling behavior of rubber in bitumen. A good correlation between the simulation results and the previously reported evidences was observed. The effects of bitumen composition, rubber type and size, interaction temperature and time on swelling were successfully demonstrated by using the developed model with dedicated input parameters. With this study as a foundation, the estimated rubber swelling behavior in bitumen can be implemented into suitable micromechanical models to predict the viscoelastic properties of CRMB and consequently to optimize the design and process of bitumen-rubber blends.","Crumb rubber modified bitumen; Diffusion; Finite element method; Multiphysics; Swelling","en","journal article","","","","","","Accepted author manuscript","","2021-04-23","","","Pavement Engineering","","",""
"uuid:529ee65c-4233-46a3-95f7-81e6e039cad2","http://resolver.tudelft.nl/uuid:529ee65c-4233-46a3-95f7-81e6e039cad2","Scenario-based extreme flood risk of residential buildings and household properties in Shanghai","Shan, Xinmeng (Shanghai Normal University); Wen, Jiahong (Shanghai Normal University); Zhang, Min (Shanghai Normal University; East China Normal University); Wang, Luyang (Shanghai Normal University); Ke, Q. (TU Delft Hydraulic Structures and Flood Risk); Li, Weijiang (Shanghai Normal University); Du, Shiqiang (Shanghai Normal University); Shi, Yong (Zhengzhou University); Chen, Kun (Shanghai Normal University)","","2019","Extreme flooding usually causes huge losses of residential buildings and household properties, which is critical to flood risk analysis and flood resilience building in Shanghai. We developed a scenario-based multidisciplinary approach to analyze the exposure, losses and risks of residential buildings and household properties, and their spatial patterns at the neighborhood committee level in Shanghai, based on extreme storm flood scenarios of 1/200, 1/500, 1/1000 and 1/5000-year. Our findings show that the inundation area of the residential buildings caused by a 1/200-year storm flood reaches 24.9 km2, and the total loss of residential buildings and household properties is 29.7 billion CNY (Chinese Yuan) (or 4.4 billion USD), while the inundation area of residential buildings and the total loss increases up to 162.4 km2 and 366.0 billion CNY (or 54.2 billion USD), respectively for a 1/5000-year storm flood. The estimated average annual loss (AAL) of residential buildings and household properties for Shanghai is 590 million CNY/year (or 87.4 million USD/year), with several hot spots distributed around the main urban area and on the bank of the Hangzhou Bay. Among sixteen districts, Pudong has the highest exposure and annual expected loss, while the inner city is also subject to extreme flooding with an AAL up to near half of the total. An analysis of flood risk in each of 209 subdistricts/towns finds that those most vulnerable to storm flooding are concentrated in Pudong, Jiading, Baoshan Districts and the inner city. Our work can provide meaningful information for risk-sensitive urban planning and resilience building in Shanghai. The methodology can also be used for risk analysis in other coastal cities facing the threat of storm flooding.","Extreme flooding; Household property; Residential building; Risk analysis; Shanghai","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:c98e848f-f865-4b52-89cb-3a9422ca9239","http://resolver.tudelft.nl/uuid:c98e848f-f865-4b52-89cb-3a9422ca9239","Co-designing with people with dementia: A scoping review of involving people with dementia in design research","Wang, G. (TU Delft Applied Ergonomics and Design); Marradia, Chiara (Student TU Delft); Albayrak, A. (TU Delft Applied Ergonomics and Design); van der Cammen, T.J.M. (TU Delft Applied Ergonomics and Design; Erasmus MC)","","2019","Co-designing with people with dementia (PwD) can uncover their needs and preferences, which have been often overlooked. It is difficult for PwD to understand designers and express themselves in a conventional co-design session. This study aims to evaluate the effects of involving PwD in design research on both PwD and the design process; to identify the trends of involving PwD in design research; to extract tools, recommendations, and limitations of involving PwD from reviewed studies to update the recommendations on how to co-design with PwD. A scoping review was carried out within the electronic databases PubMed and Scopus, and eight research questions were proposed, in order to gain specific knowledge on the involvement of PwD in design research. Twenty-six studies met the inclusion criteria, and 32 sessions were evaluated. Beneficial effects on both PwD and the design process were reported. The number of studies involving PwD in the moderate and severe stages of dementia has increased. Based on the review, an update of the existing tools and recommendations for co-designing with PwD is provided and a list of limitations of involving PwD is presented. The review shows that involving PwD in design research is beneficial for both the PwD and the design process, and there is a shift towards involving people who are in the moderate and severe stages of dementia. The authors propose that multidisciplinary meetings and case studies should be carried out to evaluate and refine the list of tools and recommendations as well as the list of limitations generated in this review.","Co-design; Dementia stage; Design process; Design research; Recommendations; Scoping review","en","review","","","","","","","","","","","Applied Ergonomics and Design","","",""
"uuid:50ed4f22-38ce-4860-a52b-4cf7c2c38250","http://resolver.tudelft.nl/uuid:50ed4f22-38ce-4860-a52b-4cf7c2c38250","Bulk viscosity of CO2 from Rayleigh-Brillouin light scattering spectroscopy at 532 nm","Wang, Yuanqing (Vrije Universiteit Amsterdam); Ubachs, Wim (Vrije Universiteit Amsterdam); van de Water, W. (TU Delft Fluid Mechanics)","","2019","Rayleigh-Brillouin scattering spectra of CO 2 were measured at pressures ranging from 0.5 to 4 bars and temperatures from 257 to 355 K using green laser light (wavelength 532 nm, scattering angle of 55.7°). These spectra were compared to two line shape models, which take the bulk viscosity as a parameter. One model applies to the kinetic regime, i.e., low pressures, while the second model uses the continuum, hydrodynamic approach and takes the rotational relaxation time as a parameter, which translates into the bulk viscosity. We do not find a significant dependence of the bulk viscosity with pressure or temperature. At pressures where both models apply, we find a consistent value of the ratio of bulk viscosity over shear viscosity η b /η s = 0.41 ± 0.10. This value is four orders of magnitude smaller than the common value that is based on the damping of ultrasound and signifies that in light scattering only relaxation of rotational modes matters, while vibrational modes remain ""frozen.""","","en","journal article","","","","","","","","2020-04-17","","","Fluid Mechanics","","",""
"uuid:fc427072-c32b-42c5-ac92-11779370db0c","http://resolver.tudelft.nl/uuid:fc427072-c32b-42c5-ac92-11779370db0c","Socioeconomic effects of aviation biofuel production in Brazil: A scenarios-based Input-Output analysis","Wang, Z. (TU Delft BT/Biotechnology and Society); Pashaei Kamali, F. (TU Delft BT/Biotechnology and Society); Osseweijer, P. (TU Delft BT/Biotechnology and Society); Posada Duque, J.A. (TU Delft BT/Biotechnology and Society)","","2019","Derived from renewable feedstocks, aviation biofuel is generally perceived as inherently sustainable. However, its production involves a wide range of sectors and interacts with different actors in society. It is therefore important to understand and evaluate not only the environmental impacts of that process, but also its socioeconomic effects. At present, empirical studies assessing socioeconomic aspects of aviation biofuel are rare in scientific literature. The aim of this study, therefore, is to assess key effects of aviation biofuel production on employment, GDP, and trade balance. A scenarios-based Input-Output (IO) analysis was used to evaluate these socioeconomic effects, taking Brazilian aviation biofuel production to 2050 as an example. To address the uncertainty of IO analysis, we have proposed a stochastic simulation approach for the technical coefficients in the IO model. Four distinct scenarios were developed. In each, three potential combinations of technologies and feedstocks for producing aviation biofuel were evaluated: sugarcane via alcohol to jet (ATJ), macauba via hydro-processed esters and fatty acids (HEFA), and eucalyptus via Fischer-Tropsch (FT). Among other things, we found that the production of aviation biofuel would create around 12,000–65,000 jobs, while contributing US$200-1100 million to Brazil's GDP under different scenarios with different supply chains. The socioeconomic effects calculated deterministically were generally higher than the stochastic outcomes, which can be explained by factors such as technological learning and economic growth. Aviation biofuel production showed large positive net socioeconomic effects on employment and GDP, although some of the fossil sectors would be negatively affected. Overall, the macauba-HEFA chain (with the highest effects on employment and GDP, and the lowest effects on imports) seemed to be the most favorable of the scenarios studied, despite the relatively high level of uncertainty associated with it.","Aviation biofuel; Employment; Input-output analysis; Social development; Socioeconomic effect; Sustainability","en","journal article","","","","","","Accepted Author Manuscript","","2021-05-22","","","BT/Biotechnology and Society","","",""
"uuid:bb446724-a85d-4b1f-887c-2806b6260f88","http://resolver.tudelft.nl/uuid:bb446724-a85d-4b1f-887c-2806b6260f88","Guided or factual computer support for kidney patients with different experience levels and medical health situations: Preferences and usage","Wang, W. (TU Delft Interactive Intelligence; TNO); van Lint, Céline L. (Leiden University Medical Center); Brinkman, W.P. (TU Delft Interactive Intelligence); Rövekamp, Ton J.M. (TNO); van Dijk, Sandra (Leiden University Medical Center; Universiteit Leiden); van der Boog, Paul (Leiden University Medical Center); Neerincx, M.A. (TU Delft Interactive Intelligence; TNO)","","2019","Personalization of eHealth systems is a promising technique for improving patients’ adherence. This paper explores the possibility of personalisation based on the patients’ medical health situation and on their health literacy. The study is set within the context of a self-management support system (SMSS) for renal transplant patients. A SMSS is designed with layering, nudging, emphaticizing, and focusing principles. It has two communication styles: (1) a guided style that provided more interpretation support and addressed emotional needs; and (2) a factual style that showed only measurement history, medical information, and recommendations. To evaluate the design, 49 renal transplant patients with three different experience levels participated in a lab study, in which they used the system in imaginary scenarios to deal with three medical health situations (alright, mild concern, and concern). A 96% understanding and 87% adherence rate was observed, with a significant interaction effect on adherence between patient group and health situation. Furthermore, compared to recently transplanted patients, not recently transplanted patients were relatively more positive towards the factual than the guided communication style in the “alright” condition. Furthermore, additional medical information was searched more often in health situations that causes mild concern and a majority of patients did not change the communication style to their preferred styles. By attuning the communication style to patient’s experience and medical health situation according to the applied principles and acquired insights, SMSSs are expected to be better used.","Adherence; Explainable artificial intelligence; Health literacy; Renal transplant patient; Self-management support system; User interface","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-12-03","","","Interactive Intelligence","","",""
"uuid:ca6b050f-574a-4463-baea-8c2c30e9defd","http://resolver.tudelft.nl/uuid:ca6b050f-574a-4463-baea-8c2c30e9defd","Numerical study of the counterflow diffusion flames of methanol hydrothermal combustion: The real-fluid effects and flamelet analysis","Ren, M. (TU Delft Fluid Mechanics; Xi’an Jiaotong University); Wang, Shuzhong (Xi’an Jiaotong University); Roekaerts, D.J.E.M. (TU Delft Fluid Mechanics)","","2019","Counterflow diffusion flames of methanol hydrothermal combustion are investigated to improve the understanding of hydrothermal flames. It is indicated that the thermodynamic properties by the Peng-Robinson equation of state and the modified transport properties can reduce the flame temperature by about 500 K. The Takahashi correlation for mass diffusivity is found to be appropriate for hydrothermal combustion through comparison with the experimental data of Wellig et al. (J. Supercrit. Fluids, 2009, 49, 1). Compared to the Kolmogorov length scale in the experimental combustor, the thickness of the calculated counterflow flame is ten times larger, which means that the flame would be affected by the turbulence. The flame stable range is also reproduced well by the developed hydrothermal counterflow flame model. In the end, a Flamelet Generated Manifold (FGM) table is generated, promising to provide good closure of the non-equilibrium chemical source term in further turbulent flame simulations.","Counterflow flames; FGM (Flamelet Generated Manifold) model; Flamelet; Hydrothermal combustion; Real-fluid properties; SCWO (Supercritical Water Oxidation)","en","journal article","","","","","","Accepted Author Manuscript","","2021-06-13","","","Fluid Mechanics","","",""
"uuid:845ff0b2-e5e9-428b-a6f8-e1bcf5962866","http://resolver.tudelft.nl/uuid:845ff0b2-e5e9-428b-a6f8-e1bcf5962866","Efficient Li-Metal Plating/Stripping in Carbonate Electrolytes Using a LiNO3-Gel Polymer Electrolyte, Monitored by Operando Neutron Depth Profiling","Liu, M. (TU Delft RST/Storage of Electrochemical Energy); Cheng, Z. (TU Delft RST/Storage of Electrochemical Energy; Nanjing University); Qian, K. (TU Delft RST/Storage of Electrochemical Energy); Verhallen, T.W. (TU Delft RST/Storage of Electrochemical Energy); Wang, C. (TU Delft RST/Storage of Electrochemical Energy); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2019","The development of safe and high-performance Li-metal anodes is crucial to meet the demanded increase in energy density of batteries. However, severe reactivity of Li metal with typical electrolytes and dendrite formation leads to a poor cycle life and safety concerns. Therefore, it is essential to develop electrolytes that passivate the reactivity toward Li metal and suppress dendrite formation. Carbonate electrolytes display severe reactivity toward Li metal; however, they are preferred above the more volatile ether-based electrolytes. Here, a carbonate electrolyte gel polymer approach is combined with LiNO3 as an additive to stabilize Li-metal plating. This electrolyte design strategy is systematically monitored by operando neutron depth profiling (NDP) to follow the evolution of the plated Li-metal density and the inactive lithium in the solid electrolyte interface (SEI) during cycling. Individually, the application of the LiNO3 electrolyte additive and the gel polymer approach are shown to be effective. Moreover, when used in conjunction, the effects are complementary in increasing the plated Li density, reducing inactive Li species, and reducing the overpotentials. The LiNO3 additive leads to more compact plating; however, it results in a significant buildup of inactive Li species in a double-layer SEI structure, which challenges the cell performance over longer cycling. In contrast, the gel polymer strongly suppresses the buildup of inactive Li species by immobilizing the carbonate electrolyte species; however, the plating is less dense and occurs with a significant overpotential. Combining the LiNO3 additive with the gel polymer approach results in a thin and homogeneous SEI with a high conductivity through the presence of Li3N and a limited buildup of inactive Li species over cycling. Through this approach, even high plating capacities, reaching 7 mAh/cm2, can be maintained at a high efficiency. The rational design strategy, empowered by monitoring the Li-density evolution, demonstrates the possibilities of achieving stable operation of Li metal in carbonate-based electrolytes.","","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:a309e294-5ab4-455e-9321-7461bd970d2e","http://resolver.tudelft.nl/uuid:a309e294-5ab4-455e-9321-7461bd970d2e","Enhancing Indoor IoT Communication with Visible Light and Ultrasound","Haus, Michael (Technische Universität München); Ding, Aaron Yi (TU Delft Information and Communication Technology); Wang, Qing (Katholieke Universiteit Leuven); Toivonen, Juhani (University of Helsinki); Tonetto, Leonardo (Technische Universität München); Tarkoma, Sasu (University of Helsinki); Ott, Jorg (Technische Universität München)","","2019","The number of deployed Internet of Things (IoT) devices is steadily increasing to manage and interact with community assets of smart cities, such as transportation systems and power plants. This may lead to degraded network performance due to the growing amount of network traffic and connections generated by various IoT devices. To tackle these issues, one promising direction is to leverage the physical proximity of communicating devices and inter-device communication to achieve low latency, bandwidth efficiency, and resilient services. In this work, we aim at enhancing the performance of indoor IoT communication (e.g., smart homes, SOHO) by taking advantage of emerging technologies such as visible light and ultrasound. This approach increases the network capacity, robustness of network connections across IoT devices, and provides efficient means to enable distance-bounding services. We have developed communication modules using off-the-shelf components for visible light and ultrasound and evaluate their network performance and energy consumption. In addition, we show the efficacy of our communication modules by applying them in a practical indoor IoT scenario to realize secure IoT group communication.","Edge computing; IoT; Multi-access; Proximity-aware device grouping; Ultrasound; Visible light","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","","","","","","Information and Communication Technology","","",""
"uuid:18f036a0-d2ff-4d4f-9c90-f22295621cfa","http://resolver.tudelft.nl/uuid:18f036a0-d2ff-4d4f-9c90-f22295621cfa","New Deep-Blue-Emitting Ce-Doped A4- mBnC19+2 mX29+ m (A = Sr, La; B = Li; C = Si, Al; X = O, N; 0 ≤ m ≤ 1; 0 ≤ n ≤ 1) Phosphors for High-Color-Rendering Warm White Light-Emitting Diodes","Wang, Chun Yun (National Institute for Materials Science; Hokkaido University; Tsinghua University); Takeda, Takashi (National Institute for Materials Science; Hokkaido University); ten Kate, O.M. (TU Delft ChemE/Product and Process Engineering; National Institute for Materials Science); Funahashi, Shiro (National Institute for Materials Science); Xie, Rong Jun (Xiamen University); Takahashi, Kohsei (National Institute for Materials Science); Hirosaki, Naoto (National Institute for Materials Science)","","2019","A new sialon Eu3.60LiSi13.78Al6.03O6.82N22.59 has been discovered via the single-particle diagnosis approach. Its crystal structure (space group P3m1) was solved and refined from single-crystal X-ray diffraction data. It has the interesting feature of two types of disorder at the Eu2 site: positional disorder (Eu2a/Eu2b) and substitutional disorder with (Si/Al)2(O/N). The structure is generalized to the formula A4-mBnC19+2mX29+m (A = Sr, La, Eu, Ce; B = Li; C = Si, Al; X = O, N; 0 ≤ m ≤ 1; 0 ≤ n ≤ 1), of which Sr3.61LiSi14.27Al5.61O6.19N23.25 (Sr-sialon, m = 0.41, n = 1) and La2.85Sr0.76LiSi14.86Al4.93O2.89N26.51 (LaSr-sialon, m = 0.40, n = 1) are two examples that have been obtained as a single-phase powder. Sr-sialon:Eu and LaSr-sialon:Eu both show blue to yellow emission, depending on the Eu concentration, whereas Sr-sialon:1% Ce shows a deep-blue emission band centered at 422 nm with a full width at half-maximum of 80 nm and an internal quantum efficiency of 80% (λex = 355 nm). The latter phosphor has very good thermal stability of both emission intensity and color. A white light-emitting diode (LED) containing the newly discovered Sr-sialon:5% Ce as the blue phosphor component shows excellent color-rendering indices (Ra = 96 and R12 = 97) with a correlated color temperature of 4255 K. This indicates that Sr-sialon:Ce is a highly promising deep-blue phosphor for illumination grade white LEDs.","deep-blue-emitting; high-color-rendering; new sialon phosphors; single-particle diagnosis approach; warm white LEDs","en","journal article","","","","","","Accepted Author Manuscript","","2020-07-11","","","ChemE/Product and Process Engineering","","",""
"uuid:32521168-4d03-41f2-9e5c-c759cbf43972","http://resolver.tudelft.nl/uuid:32521168-4d03-41f2-9e5c-c759cbf43972","Bayesian operational modal analysis of offshore rock lighthouses: Close modes, alignment, symmetry and uncertainty","Brownjohn, James Mark William (University of Exeter; Full Scale Dynamics LTD); Raby, Alison (Plymouth University); Au, Siu Kui (Nanyang Technological University); Zhu, Zuo (University of Liverpool); Wang, Xinrui (University of Liverpool); Antonini, A. (TU Delft Coastal Engineering); Pappas, Athanasios (University College London (UCL)); D'Ayala, Dina (University College London (UCL))","","2019","Despite use of GPS, lighthouses remain critical infrastructure for preserving safety of mariners and maritime trade, and the most dramatic examples are probably the Victorian era masonry towers located on remote offshore reefs around the British Isles and exposed to extreme weather conditions. Due to their age and likely increasing future loading, dynamic field investigations were undertaken for condition assessment. The field investigations of a sample of seven lighthouses had focused on experimental modal analysis (EMA) of shaker force and acceleration response data in order to identify sets of modal parameters (MPs) specifically including modal mass, which is useful for linking loading and response. However, the EMA missed significant useful information, which could be recovered from operational modal analysis (OMA) of additional ambient vibration data recorded during the field measurements, as well as from subsequent long-term monitoring of Wolf Rock lighthouse. Horizontal vibration modes of the towers appear as pairs of modes of similar shape and with close natural frequency due to the quasi-axisymmetric structural form(s), and the lowest frequency pairs are most important to identify since they contribute most to response to breaking wave impact loads. Reliably identifying both the close natural frequencies and the corresponding mode shape orientations was impossible with EMA. Bayesian OMA (BAYOMA) provided the most insight into the modal behaviour, while at the same time providing insight into the fundamental limitations for identifying close modes. Specific conclusions from the OMA described in this paper are: • Due to varying degree of asymmetry in the ‘concave elliptic frustum’ lighthouse shapes, mode frequencies in a pair were found to differ by between 0.75% and 3.8%. • Unlike EMA, OMA was able to identify (or estimate) the horizontal directions of the mode pairs corresponding to the very close natural frequencies. • Visually apparent structural symmetry may not be strongly linked to mode shape orientations. • Mode frequency variation over time may exceed -but is not accounted for in- the calculated identification uncertainty of MPs. • There is a trade-off between mode shape orientation uncertainty and closeness of frequencies in a close-mode pair.","BAYOMA; Close modes; Lighthouse condition assessment system identification; OMA","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:a2951180-d0b5-43ab-9c23-312fe8869c2e","http://resolver.tudelft.nl/uuid:a2951180-d0b5-43ab-9c23-312fe8869c2e","The dynamic behavior of gas hydrate dissociation by heating in tight sandy reservoirs: A molecular dynamics simulation study","Fang, Bin (China University of Geosciences, Wuhan); Ning, Fulong (China University of Geosciences, Wuhan; Qingdao National Laboratory for Marine Science and Technology); Ou, Wenjia (China University of Geosciences, Wuhan); Wang, Dongdong (China University of Geosciences, Wuhan); Zhang, Zhun (China University of Geosciences, Wuhan; Qingdao National Laboratory for Marine Science and Technology); Yu, Yanjiang (Ministry of Land and Resources of China); Lu, Hongfeng (Ministry of Land and Resources of China); Wu, Jianyang (Xiamen University); Vlugt, T.J.H. (TU Delft Engineering Thermodynamics)","","2019","Knowledge on the kinetics of gas hydrate dissociation in microporous sediments is very important for developing safe and efficient approaches to gas recovery from natural gas hydrate (NGH) deposits. Herein, molecular dynamics (MD) simulations are used to study the dissociation kinetics in microporous sediments. The hydrate phase occupies a confined sandy nanopore formed by two hydroxylated silica surfaces with a buffering water layer between the hydrate and silica phase, meanwhile, this system is in contact with the bulk phase outside the pore. The hydrates in this sediment system dissociate layer-by-layer in a shrinking core manner. The released methane molecules aggregate and eventually evolve into nanobubbles, most of which are spherical cap-shaped on the hydroxylated silica surfaces. At high initial temperatures, a faster decomposition of the hydrate phase is observed, however, fewer methane molecules migrate to the bulk phase from the pore phase. These phenomena may occur because more methane molecules are released from the hydrate phase and facilitate the formation of nanobubbles with large heat injection; these nanobubbles can stably adsorb on the surface of silica and capture the surrounding methane molecules, thereby decreasing the number of methane molecules in the water phase. In addition, the injection speed of heat flow should be significantly increased at high dissociation temperatures when using the thermal stimulation method to extract gas from hydrates in tight sediments. This study provides molecular level insight into the kinetic mechanism of hydrate dissociation and theoretical guidance for gas production by thermal injection from sediments with low permeabilities.","Dissociation kinetics; Heat injection; Methane hydrate; Molecular simulation; Nanobubbles; Tight sandy sediments","en","journal article","","","","","","Accepted Author Manuscript","","2021-09-10","","","Engineering Thermodynamics","","",""
"uuid:dd3f7da5-0a28-4569-b7f1-c8978a489db5","http://resolver.tudelft.nl/uuid:dd3f7da5-0a28-4569-b7f1-c8978a489db5","A software-in-the-loop implementation of adaptive formation control for fixed-wing UAVs","Yang, Jun (China State Shipbuilding Corporation); Wang, X. (TU Delft Team Bart De Schutter); Baldi, S. (TU Delft Team Bart De Schutter; Southeast University); Singh, Satish (Student TU Delft); Fari, S. (Politecnico di Milano; Institute of Space Systems)","","2019","This paper discusses the design and software-in-the-loop implementation of adaptive formation controllers for fixed-wing unmanned aerial vehicles (UAVs) with parametric uncertainty in their structure, namely uncertain mass and inertia. In fact, when aiming at autonomous flight, such parameters cannot assumed to be known as they might vary during the mission (e.g. depending on the payload). Modelingg and autopilot design for such autonomous fixed-wing UAVs are presented. The modeling is implemented in Matlab, while the autopilot is based on ArduPilot, a popular open-source autopilot suite. Specifically, the ArduPilot functionalities are emulated in Matlab according to the Ardupilot documentation and code, which allows us to perform software-in-the-loop simulations of teams of UAVs embedded with actual autopilot protocols. An overview of realtime path planning, trajectory tracking and formation control resulting from the proposed platform is given. The software-in-the-loop simulations show the capability of achieving different UAV formations while handling uncertain mass and inertia.","adaptive formation control; ArduPilot; Fixed-wing UAVs; software-in-the-loop simulations","en","journal article","","","","","","Accepted Author Manuscript","","","","","Team Bart De Schutter","","",""
"uuid:9e5de706-0275-46b3-b074-aa291b9247d7","http://resolver.tudelft.nl/uuid:9e5de706-0275-46b3-b074-aa291b9247d7","Structure-activity relationships in metal organic framework derived mesoporous nitrogen-doped carbon containing atomically dispersed iron sites for CO2 electrochemical reduction","Sun, X. (TU Delft ChemE/Catalysis Engineering); Wang, R. (TU Delft ChemE/Catalysis Engineering); Ould-Chikh, Samy (King Abdullah University of Science and Technology); Osadchii, D. (TU Delft ChemE/Catalysis Engineering); Li, G. (TU Delft ChemE/Inorganic Systems Engineering; TU Delft ChemE/Catalysis Engineering); Aguilar, Antonio (Université Grenoble Alpes); Hazemann, Jean louis (Université Grenoble Alpes); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering); Gascon, Jorge (TU Delft ChemE/Catalysis Engineering; King Abdullah University of Science and Technology)","","2019","Mesoporous nitrogen-doped carbon nanoparticles with atomically dispersed iron sites (named mesoNC-Fe) are synthesized via high-temperature pyrolysis of an Fe containing ZIF-8 MOF. Hydrolysis of tetramethyl orthosilicate (TMOS) in the MOF framework prior to pyrolysis plays an essential role in maintaining a high surface area during the formation of the carbon structure, impeding the formation of iron (oxide) nanoparticles. To gain inside on the nature of the resulting atomically dispersed Fe moieties, HERFD-XANES, EXAFS and valence-to-core X-ray emission spectroscopies have been used. The experimental spectra (both XAS and XES) combined with theoretical calculations suggest that iron has a coordination sphere including a porphyrinic environment and OH/H2O moieties responsible for the high activity in CO2 electroreduction. DFT calculations demonstrate that CO formation is favored in these structures because the free energy barriers of *COOH formation are decreased and the adsorption of *H is impeded. The combination of such a unique coordination environment with a high surface area in the carbon structure of mesoNC-Fe makes more active sites accessible during catalysis and promotes CO2 electroreduction.","Atomically dispersed sites; CO; Electroreduction; Iron","en","journal article","","","","","","Accepted Author Manuscript","","2021-09-25","","","ChemE/Catalysis Engineering","","",""
"uuid:86521684-e047-449a-98c2-335de1de6fa9","http://resolver.tudelft.nl/uuid:86521684-e047-449a-98c2-335de1de6fa9","Super-Resolution Channel Estimation for Arbitrary Arrays in Hybrid Millimeter-Wave Massive MIMO Systems","Wang, Yue (George Mason University); Zhang, Yu (Nanjing University of Aeronautics and Astronautics; George Mason University); Tian, Zhi (George Mason University); Leus, G.J.T. (TU Delft Signal Processing Systems); Zhang, Gong (Nanjing University of Aeronautics and Astronautics)","","2019","This paper develops efficient channel estimation techniques for millimeter-wave (mmWave) massive multiple-input multiple-output (MIMO) systems under practical hardware limitations, including an arbitrary array geometry and a hybrid hardware structure. Taking on an angle-based approach, this work adopts a generalized array manifold separation approach via Jacobi-Anger approximation, which transforms a non-ideal, non-uniform array manifold into a virtual array domain with a desired uniform geometric structure to facilitate super-resolution angle estimation and channel acquisition. Accordingly, structure-based optimization techniques are developed to effectively estimate both the channel covariance and the instantaneous channel state information (CSI) within a short sensing time. The different time-varying scales of channel path angles versus path gains are capitalized to design a two-step CSI estimation scheme that can quickly sense fading channels. Theoretical results are provided on the fundamental limits of the proposed technique in terms of sample efficiency. For computational efficiency, a fast iterative algorithm is developed via the alternating direction method of multipliers. Other related issues such as spurious-peak cancellation in non-uniform linear arrays and extensions to higher-dimensional cases are also discussed. Simulations testify the effectiveness of the proposed approaches in hybrid mmWave massive MIMO systems with arbitrary arrays.","Arbitrary array; gridless compressive sensing; hybrid structure; Jacobi-Anger approximation; mmWave massive MIMO; super-resolution channel estimation; Vandermonde structure","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-02-26","","","Signal Processing Systems","","",""
"uuid:43685fe4-4548-4e5e-999d-5b610ff75d5d","http://resolver.tudelft.nl/uuid:43685fe4-4548-4e5e-999d-5b610ff75d5d","Tandem Interface and Bulk Li-Ion Transport in a Hybrid Solid Electrolyte with Microsized Active Filler","Liu, M. (TU Delft RST/Storage of Electrochemical Energy); Cheng, Z. (TU Delft RST/Storage of Electrochemical Energy; Nanjing University); Ganapathy, S. (TU Delft RST/Storage of Electrochemical Energy); Wang, C. (TU Delft RST/Storage of Electrochemical Energy); Haverkate, Lucas A. (TNO); Tułodziecki, Michał (TNO); Unnikrishnan, Sandeep (TNO); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2019","In common hybrid solid electrolytes (HSEs), either the ionic conductivity of the polymer electrolyte is enhanced by the presence of a nanosized inorganic filler, which effectively decrease the glass-transition temperature, or the polymer solid electrolyte acts mostly as a flexible host for the inorganic solid electrolyte, the latter providing the conductivity. Here a true HSE is developed that makes optimal use of the high conductivity of the inorganic solid electrolyte and the flexibility of the polymer matrix. It is demonstrated that the LAGP (Li1.5Al0.5Ge1.5(PO4)3) participates in the overall conductivity and that the interface environment between the poly(ethylene oxide) (PEO) and LAGP plays a key role in utilizing the high conductivity of the LAGP. This HSE demonstrates promising cycling versus Li-metal anodes and in a full Li-metal solid-state battery. This strategy offers a promising route for the development of Li-metal solid-state batteries, aiming for safe and reversible high-energy-density batteries.","","en","journal article","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:b72b58f2-80f9-4955-9e01-317e4ef8ce9f","http://resolver.tudelft.nl/uuid:b72b58f2-80f9-4955-9e01-317e4ef8ce9f","Adverse effects of potassium on NOx reduction over Di-Air catalyst (Rh/La-Ce-Zr)","Wang, Y. (TU Delft ChemE/Catalysis Engineering); Makkee, M. (TU Delft ChemE/Catalysis Engineering)","","2019","The influence of potassium in Rh on a lanthium promoted zirconia stablised ceria (CZ) catalysts was studied toward NOxreduction reactivity and selectivity. The results are compared with a Rh/CZ catalyst. The samples were characterised by N2 adsorption, XRD, SEM, ICP, and H2-TPR. The study highlighted the importance of stored NOx regeneration over potassium in determining the overall performance of the Rh/K/CZ catalyst. The NOx stored over Rh/K/CZ in the previous NO gas stream cannot be regenerated sufficiently during the C3H6 gas stream, and stored NOxgradually decreased from one cycle to the next, resulting in deteriorating performance of Rh/K/CZ. Besides, problem of NOx slip, the formation of both NH3 and N2O (selectivities up to 30% for each side product) were observed by the addition of potassium into the Rh/CZ catalyst system, depending on the reaction conditions applied and the severity of the catalyst deactivation.","Ceria; Di-Air; NO Reduction; Potassium; Rh","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:e38b067f-5984-4f66-ad37-aa7382722b2a","http://resolver.tudelft.nl/uuid:e38b067f-5984-4f66-ad37-aa7382722b2a","Maximizing Ag Utilization in High-Rate CO2 Electrochemical Reduction with a Coordination Polymer-Mediated Gas Diffusion Electrode","Wang, R. (TU Delft ChemE/Catalysis Engineering); Haspel, Henrik (King Abdullah University of Science and Technology); Pustovarenko, Alexey (TU Delft ChemE/Catalysis Engineering; King Abdullah University of Science and Technology); Dikhtiarenko, A. (TU Delft ChemE/Catalysis Engineering; King Abdullah University of Science and Technology); Osadchii, D. (TU Delft ChemE/Catalysis Engineering); Ma, M. (TU Delft ChemE/Materials for Energy Conversion and Storage); Smith, W.A. (TU Delft ChemE/Materials for Energy Conversion and Storage); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering); Gascon, Jorge (King Abdullah University of Science and Technology)","","2019","We report the preparation and electrocatalytic performance of silver-containing gas diffusion electrodes (GDEs) derived from a silver coordination polymer (Ag-CP). Layer-by-layer growth of the Ag-CP onto porous supports was applied to control Ag loading. Subsequent electro-decomposition of the Ag-CP resulted in highly selective and efficient CO2-to-CO GDEs in aqueous CO2 electroreduction. Afterward, the metal-organic framework (MOF)-mediated approach was transferred to a gas-fed flow electrolyzer for high current density tests. The in situ formed GDE, with a low silver loading of 0.2 mg cm-2, showed a peak performance of jCO ≈ 385 mA cm-2 at around -1.0 V vs RHE and stable operation with high FECO (>96%) at jTotal = 300 mA cm-2 over a 4 h run. These results demonstrate that the MOF-mediated approach offers a facile route for manufacturing uniformly dispersed Ag catalysts for CO2 electrochemical reduction by eliminating ill-defined deposition steps (drop-casting, etc.) while allowing control of the catalyst structure through self-assembly.","","en","journal article","","","","","","Accepted Author Manuscript","","2020-07-29","","","ChemE/Catalysis Engineering","","",""
"uuid:8b50a05a-bde0-47b6-9708-275d6e2f87e6","http://resolver.tudelft.nl/uuid:8b50a05a-bde0-47b6-9708-275d6e2f87e6","Enhancement of Transient Stability in Power Systems with High Penetration Level of Wind Power Plants","Wang, D. (TU Delft Intelligent Electrical Power Grids); Rueda, José L. (TU Delft Intelligent Electrical Power Grids); Perilla Guerra, A.D. (TU Delft Intelligent Electrical Power Grids); Rakhshani, E. (TU Delft Intelligent Electrical Power Grids); Palensky, P. (TU Delft Intelligent Electrical Power Grids); van der Meijden, M. (TenneT TSO B.V.)","","2019","Due to the power electronic converter based interface and maximum power control strategy, wind generators cannot directly respond to power system transients. This brings new challenges on power system transient stability. Taking wind turbine type 4 (WT4) as one example, this paper analyses its influence on transient stability with respect to locations, low voltage ride through parameters, wind power plant installation capacity and penetration levels. Based on the sensitivity analysis carried out for the influence of WT4, a supplementary transient stability control is proposed. The results on a 3-area system show that this supplementary control can improve transient stability of power systems with high penetration of wind power.","Low voltage ride through; Migrate; Sensitivity analysis; Transient stability; Wind turbine control","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-12-08","","","Intelligent Electrical Power Grids","","",""
"uuid:9f1d6f9c-9543-4501-907e-d3c3bc9b34bd","http://resolver.tudelft.nl/uuid:9f1d6f9c-9543-4501-907e-d3c3bc9b34bd","Immersion precipitation route towards high performance thick and flexible electrodes for Li-ion batteries","Harks, P.P.R.M.L. (TU Delft ChemE/Materials for Energy Conversion and Storage); Robledo, C.B. (TU Delft Energy Technology); George, C. (TU Delft RST/Storage of Electrochemical Energy); Wang, C. (TU Delft RST/Storage of Electrochemical Energy); van Dijk, Thomas (E-Stone); Sturkenboom, Leon (E-Stone); Roesink, Erik D.W. (University of Twente); Mulder, F.M. (TU Delft ChemE/Materials for Energy Conversion and Storage)","","2019","Enabling the transition to renewable power sources requires further optimization of batteries in terms of energy/power density and cost-effectiveness. Increasing the practical thickness of Li ion battery electrodes not only can improve energy density on cell level but reduces manufacturing cost. However, thick electrodes exhibit sluggish charge-transport kinetics and are mechanically less stable, typically resulting in substandard battery performance compared to the current commercial standards (~50 μm). Here we disclose a novel method based on immersion precipitation by employing a non-solvent to solidify the battery binder, instead of solvent evaporation. This method allows for the fabrication of thick and suitable density electrodes (>100 μm with ultra-high mass loading) offering excellent electrochemical performance and mechanical stability. Using commercial electrode active materials at a remarkable mass-loading of 24 mg cm−2, the electrodes processed via immersion method are shown to deliver 3.5 mAh cm−2 at a rate of 2C and operate at rates up to 10C. As additional figure of merit, this method produces electrodes that are both stand-alone and highly flexible, which have been evaluated in flexible full-cells. Furthermore, via immersion precipitation the commonly used more toxic N-Methyl-2-pyrrolidone can be supplanted by environmentally benign dimethyl sulfoxide as solvent for processing electrode layers.","Batteries; Electrodes; Flexible batteries; Immersion precipitation; Phase inversion","en","journal article","","","","","","","","","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:588da2f8-7c8c-45ea-a777-6e14bc825ea7","http://resolver.tudelft.nl/uuid:588da2f8-7c8c-45ea-a777-6e14bc825ea7","Structural adaptation through stiffness tuning","Hidding, A.J. (TU Delft Architectural Engineering); Bier, H.H. (TU Delft Architectural Engineering); Wang, Qinyu (Eindhoven University of Technology); Teuffel, Patrick (Eindhoven University of Technology); Senatore, Gennaro (Swiss Federal Institute of Technology)","","2019","Adaptive design strategies have been employed to improve structural performances in terms of load-bearing efficiency and energetic impact as well as to achieve multi-functionality. In this work, we investigate a passive adaptation strategy that employs variable stiffness in robotically printed materials. This paper focuses on the design and robotic fabrication of a chaise longue that can change shape to function as both recliner and chair depending on user requirements. The approach is unique in the way computational design is linked with robotic production. In this context, the design of the chaise longue is not limited to a formal process, but extends to the synthesis of the material distribution layout in order to achieve the intended functional behaviour.","Adaptive design strategies; Robotic printing; Structural adaptation","en","journal article","","","","","","Cyber-physical Architecture #2: Apparatisation in & of Architecture ISBN 978-94-6366-200-0","","","","","Architectural Engineering","","",""
"uuid:0e031e5c-01b3-4f05-b99d-022ae45b05b5","http://resolver.tudelft.nl/uuid:0e031e5c-01b3-4f05-b99d-022ae45b05b5","A method for identifying protein complexes with the features of joint co-localization and joint co-expression in static PPI networks","Zhang, Jinxiong (South China University of Technology; Guangxi University); Zhong, Cheng (Guangxi University); Huang, Yiran (Guangxi University); Lin, H.X. (TU Delft Mathematical Physics); Wang, Mian (Guangxi University)","","2019","Identifying protein complexes in static protein-protein interaction (PPI) networks is essential for understanding the underlying mechanism of biological processes. Proteins in a complex are co-localized at the same place and co-expressed at the same time. We propose a novel method to identify protein complexes with the features of joint co-localization and joint co-expression in static PPI networks. To achieve this goal, we define a joint localization vector to construct a joint co-localization criterion of a protein group, and define a joint gene expression to construct a joint co-expression criterion of a gene group. Moreover, the functional similarity of proteins in a complex is an important characteristic. Thus, we use the CC-based, MF-based, and BP-based protein similarities to devise functional similarity criterion to determine whether a protein is functionally similar to a protein cluster. Based on the core-attachment structure and following to seed expanding strategy, we use four types of biological data including PPI data with reliability score, protein localization data, gene expression data, and gene ontology annotations, to identify protein complexes. The experimental results on yeast data show that comparing with existing methods our proposed method can efficiently and exactly identify more protein complexes, especially more protein complexes of sizes from 2 to 6. Furthermore, the enrichment analysis demonstrates that the protein complexes identified by our method have significant biological meaning.","Core-attachment structure; Joint co-expression; Joint co-localization; Protein complexes; Seed expanding strategy; Static PPI networks","en","journal article","","","","","","Accepted author manuscript","","2020-07-31","","","Mathematical Physics","","",""
"uuid:cf63d46e-48db-4b55-81e3-329719ac1028","http://resolver.tudelft.nl/uuid:cf63d46e-48db-4b55-81e3-329719ac1028","Effect of Nano-SnS and Nano-MoS2 on the corrosion protection performance of the polyvinylbutyral and zinc-rich polyvinylbutyral coatings","Qu, Zuopeng (North China Electric Power University); Wang, Lei (North China Electric Power University); Tang, H. (TU Delft Electronic Components, Technology and Materials; Changzhou Institute of Technology Research for Solid State Lighting); Ye, H. (TU Delft Electronic Components, Technology and Materials); Li, Meicheng (North China Electric Power University)","","2019","In this paper, four composite coatings of nano-SnS/polyvinylbutyral (PVB), nano-MoS2/PVB, nano-SnS-Zn/PVB, and nano-MoS2-Zn/PVB were prepared, and their anti-corrosion mechanism was analyzed by experimental and theoretical calculations. The results of the electrochemical experiments show that the effect of nano-MoS2 on the corrosion protection performance of PVB coating is better than that of nano-SnS in 3% NaCl solution, and that the addition of Zn further enhances this effect, which is consistent with the results of weight loss measurements. Furthermore, the observation of the corrosion matrix by the field emission scanning electron microscope (FESEM) further confirmed the above conclusion. At last, the molecular dynamics (MD) simulation were carried out to investigate the anti-corrosion mechanism of the nanofillers/PVB composites for the copper surface. The results show that both nano-SnS and nano-MoS2 are adsorbed strongly on the copper surface, and the binding energy of nano-MoS2 is larger than that of nano-SnS.","Anti-corrosion; Composite coating; Electrochemical test; Molybdenum disulfide (MoS); Tin sulfide (SnS)","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:25197f17-6371-4988-b7a0-90c3d77b87ac","http://resolver.tudelft.nl/uuid:25197f17-6371-4988-b7a0-90c3d77b87ac","Risk Factors and Neuropsychological Assessments of Subjective Cognitive Decline (plus) in Chinese Memory Clinic","Hao, Lixiao (Xuanwu Hospital of Capital Medical University, Beijing); Xing, Yue (University of Nottingham); Li, Xuanyu (Xuanwu Hospital of Capital Medical University, Beijing); Mu, Bin (Xuanwu Hospital of Capital Medical University, Beijing); Zhao, Weina (Hongqi Hospital of Mudanjiang Medical University, Mudanjiang); Wang, G. (TU Delft Applied Ergonomics and Design); Wang, Ting (School of General Practice and Continuing Education of Capital Medical University, Beijing); Jia, Jianguo (Xuanwu Hospital of Capital Medical University, Beijing); Han, Ying (Xuanwu Hospital of Capital Medical University, Beijing; Beijing Institute of Geriatrics, Beijing; National Clinical Research Center for Geriatric Disorders, Beijing; Beijing Institute for Brain Disorders, Beijing)","","2019","Background: Since subjective cognitive decline (SCD) was standardized in 2014, many studies have investigated its features. However, the risk of SCD (plus) progressing to AD is much higher, and yet there have been few studies reporting the risk factors and neuropsychological assessment characteristics of SCD (plus). Objective: To characterize SCD (plus) by comparing it with normal control (NC), amnesic mild cognitive impairment (aMCI), and Alzheimer Disease (AD) regarding their demographics, lifestyle, family history of dementia, multimorbidity and the neuropsychological assessments. Methods: A total of 135 participants were recruited, including 23 NC, 30 SCD (plus), 45 aMCI and 37 AD. Descriptive statistics were provided. A logistic regression model was used to analyze the affecting factors of SCD (plus), and finally the Receiver Operating Characteristic (ROC) analysis was applied to distinguish between SCD (plus) and NC. Results: (1) SCD (plus) group was younger than both the aMCI group and AD group. It consisted of more participants with mental work and higher body mass index (BMI) than the AD group. (2) Scores of Auditory Verbal Learning Test - Immediate recall (AVLT-IR) and AVLT-Long delayed recall (AVLT-LR) decreased in the following order: NC→SCD (plus)→aMCI→AD. (3) The Area Under Curve (AUC) for discriminating SCD (plus) and NC group was from 0.673 to 0.838. Conclusion: Aging is an important risk factor of both NC progressing to SCD (plus), and SCD (plus) progressing to aMCI or AD. In addition to aging, lower education level and lower BMI were significantly associated with greater odds of SCD (plus) progressing to aMCI or AD patients, whereas mental work was a protective factor of SCD (plus) progressing to AD. Finally, AVLT is a sensitive indicator of the cognitive decline and impairment in SCD (plus) in relative to normal controls.","Alzheimer Disease; neuropsychological assessment; objective cognitive features; risk factors; subjective cognitive decline","en","journal article","","","","","","","","","","","Applied Ergonomics and Design","","",""
"uuid:3c967673-b728-4ef3-ba8a-71d473b59273","http://resolver.tudelft.nl/uuid:3c967673-b728-4ef3-ba8a-71d473b59273","Potential impact of a large-scale cascade reservoir on the spawning conditions of critical species in the Yangtze River, China","Yu, Meixiu (Hohai University; Research Center for Climate Change of Ministry of Water Resources); Yang, Daqing (Environment Canada); Liu, X. (TU Delft Hydraulic Structures and Flood Risk; IHE Delft Institute for Water Education); Li, Qiongfang (Hohai University); Wang, Guoqing (Research Center for Climate Change of Ministry of Water Resources)","","2019","Dam building and reservoir operations alter the downstream hydrological regime, and as a result, affect the health of the river aquatic ecosystem, particularly for large-scale cascade reservoirs. This study investigated the impact of the Gezhouba Reservoir (GR) and the Three Gorges Reservoir (TGR) on the spawning conditions of two critical taxa, i.e., the endemic four major carps and the endangered Chinese sturgeon in the Yangtze River. We analyzed the flow, sediment, and thermal regime in these two taxa spawning seasons and compared their features between the predam and postdam periods. Our results revealed that the GR and the TGR had altered the frequency distributions of flow, sediment, and water temperature to different degrees, with the impact by the GR on the carps and Chinese sturgeon ranked as water temperature > flow, sediment > water temperature > flow, and the effect of the TGR on these two taxa were ordered as flow > water temperature, sediment > flow > water temperature. For the GR, the satisfying degree of the suitable flow and water temperature of the carps increased, whilst the suitable flow, sediment, and water temperature for the Chinese sturgeon decreased. These changes in TGR showed a significant ascending (descending) trend in the suitable flow (water temperature) for the carps, and a clear decreasing trend in the flow, sediment, and temperature for Chinese sturgeon. Both the TGR and the GR had negative impacts on the spawning of these two taxa in terms of the rising/falling flow characteristics.","Chinese sturgeon; Flow; Four major carps; Gezhouba Reservoir; Sediment; Three Gorges Reservoir; Water temperature","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:82d5b65e-f7a6-4f3e-8a2e-2d806b4af7f2","http://resolver.tudelft.nl/uuid:82d5b65e-f7a6-4f3e-8a2e-2d806b4af7f2","Bayesian oma of offshore rock lighthouses: Surprises with close modes, symmetry and alignment","Brownjohn, James (University of Exeter); Raby, Alison (Plymouth University); Au, Siu Kui (University of Liverpool); Zhu, Zuo (University of Liverpool); Wang, Xinrui (University of Liverpool); Antonini, A. (TU Delft Coastal Engineering)","Amador, Sandro D. R. (editor); Brincker, Rune (editor); Katsanos, Evangelos I. (editor); Lopez Aenlle, Manuel (editor); Fernandez, Pelayo (editor)","2019","A set of seven rock lighthouses around the British Isles was studied by a combination of forced and ambient vibration tests executed with some extreme logistical constraints. Forced vibration testing of the circular section masonry towers combined with experimental modal analysis identified modes with alignment assumed the same as the shaker as well as some interesting effects of helideck retrofit, whereas operational modal analysis revealed the considerable degree of uncertainty in mode shape alignment. Hence Bayesian operational modal analysis was used to characterise the uncertainty and find the best representation of mode shape direction. While perfectly axisymmetric towers would show a single frequency omnidirectional mode, OMA reveals the split modes and allows un unbiased view of directionality. The variability and uncertainty of these mode shape directions are further revealed using Bayesian OMA.","Assessment; Bayesian; Condition; Identification; Lighthouse; OMA; System","en","conference paper","International Operational Modal Analysis Conference (IOMAC)","","","","","Accepted Author Manuscript","","","","","Coastal Engineering","","",""
"uuid:6db72bfd-c8a5-4cc3-a639-20768c8a0863","http://resolver.tudelft.nl/uuid:6db72bfd-c8a5-4cc3-a639-20768c8a0863","Review of the recent progress on GaN-based vertical power Schottky barrier diodes (SBDs)","Sun, Y. (TU Delft Electronic Components, Technology and Materials); Kang, Xuanwu (Chinese Academy of Sciences); Zheng, Yingkui (Chinese Academy of Sciences); Lu, Jiang (Chinese Academy of Sciences); Tian, Xiaoli (Chinese Academy of Sciences); Wei, Ke (Chinese Academy of Sciences); Wu, Hao (Chinese Academy of Sciences); Wang, Wenbo; Liu, Xinyu (Chinese Academy of Sciences); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2019","Gallium nitride (GaN)-based vertical power Schottky barrier diode (SBD) has demonstrated outstanding features in high-frequency and high-power applications. This paper reviews recent progress on GaN-based vertical power SBDs, including the following sections. First, the benchmark for GaN vertical SBDs with different substrates (Si, sapphire, and GaN) are presented. Then, the latest progress in the edge terminal techniques are discussed. Finally, a typical fabrication flow of vertical GaN SBDs is also illustrated briefly.","Edge termination techniques; GaN; Schottky barrier diode (SBD); Vertical power devices","en","review","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:f6d1d9d2-4863-41ea-aa07-0c6e36e4623c","http://resolver.tudelft.nl/uuid:f6d1d9d2-4863-41ea-aa07-0c6e36e4623c","Characterization of PCB Embedded Package Materials for SiC MOSFETs","Hou, F. (TU Delft DC systems, Energy conversion & Storage; Institute of Microelectronics of Chinese Academy of Sciences); Wang, W. (TU Delft DC systems, Energy conversion & Storage); Lin, Tingyu (National Center for Advanced Packaging); Cao, Liqiang (Chinese Academy of Sciences; National Center for Advanced Packaging); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Ferreira, Jan Abraham (TU Delft ESE Programmes)","","2019","In this paper, a novel fan-out panel-level printed circuit board (PCB) embedded package technology for silicon carbide (SiC) MOSFET power module is presented to address parasitic inductances, heat dissipation, and reliability issues that are inherent with aluminum wires used in conventional packaging scheme. To withstand high temperature beyond 175 °C and high voltage over 1.2 kV and improve thermomechanical reliability of the fan-out panel-level PCB embedded SiC power module, bismaleimide-triazine (BT) laminate and prepreg with high-temperature stability, high dielectric strength, coefficient of thermal expansion (CTE) matching with SiC, and high T-g are selected as PCB embedded package materials. Then, high-temperature stabilities, dielectric breakdown strength, and thermomechanical performances of the embedded materials are characterized. The experimental results show that the PCB embedded materials can withstand high temperature beyond 200 °C and a high voltage above 1.2 kV. T-g is as high as over 260 °C, and CTE is matching with SiC. Besides, in order to provide one guideline for the high-temperature and high-pressure laminating process during the PCB embedded SiC MOSFETs packaging, cure kinetics of BT prepreg are analyzed. The results show that 1-h curing time at 280 °C curing temperature and 2-h curing time at 210 °C curing temperature can ensure the full cure of the BT prepreg.","High temperature; high voltage; material characterization; printed circuit board (PCB) embedded package; silicon carbide (SiC) MOSFETs","en","journal article","","","","","","Accepted author manuscript","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:f1254cd4-f218-49a9-a854-115742be8de0","http://resolver.tudelft.nl/uuid:f1254cd4-f218-49a9-a854-115742be8de0","Physical metallurgy-guided machine learning and artificial intelligent design of ultrahigh-strength stainless steel","Shen, Chunguang (Northeastern University China); Wang, Chenchong (Northeastern University China); Wei, Xiaolu (Northeastern University China); Li, Yong (Northeastern University China); van der Zwaag, S. (TU Delft Novel Aerospace Materials); Xu, W. (TU Delft Novel Aerospace Materials; Northeastern University China)","","2019","With the development of the materials genome philosophy and data mining methodologies, machine learning (ML) has been widely applied for discovering new materials in various systems including high-end steels with improved performance. Although recently, some attempts have been made to incorporate physical features in the ML process, its effects have not been demonstrated and systematically analysed nor experimentally validated with prototype alloys. To address this issue, a physical metallurgy (PM) -guided ML model was developed, wherein intermediate parameters were generated based on original inputs and PM principles, e.g., equilibrium volume fraction (Vf) and driving force (Df) for precipitation, and these were added to the original dataset vectors as extra dimensions to participate in and guide the ML process. As a result, the ML process becomes more robust when dealing with small datasets by improving the data quality and enriching data information. Therefore, a new material design method is proposed combining PM-guided ML regression, ML classifier and a genetic algorithm (GA). The model was successfully applied to the design of advanced ultrahigh-strength stainless steels using only a small database extracted from the literature. The proposed prototype alloy with a leaner chemistry but better mechanical properties has been produced experimentally and an excellent agreement was obtained for the predicted optimal parameter settings and the final properties. In addition, the present work also clearly demonstrated that implementation of PM parameters can improve the design accuracy and efficiency by eliminating intermediate solutions not obeying PM principles in the ML process. Furthermore, various important factors influencing the generalizability of the ML model are discussed in detail.","Alloy design; Machine learning; Physical metallurgy; Small sample problem; Stainless steel","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-02-01","","","Novel Aerospace Materials","","",""
"uuid:621872ae-1b62-452b-a34a-c9a2ad72fbbd","http://resolver.tudelft.nl/uuid:621872ae-1b62-452b-a34a-c9a2ad72fbbd","Double helical conformation and extreme rigidity in a rodlike polyelectrolyte","Wang, Ying (Virginia Tech); He, Yadong (Virginia Tech); Yu, Zhou (Virginia Tech); Gao, J. (TU Delft Novel Aerospace Materials); ten Brinck, Stephanie (Universiteit van Amsterdam); Hegde, M. (TU Delft Novel Aerospace Materials; University of North Carolina); Moore, Robert B. (Virginia Tech); Ensing, Bernd (Universiteit van Amsterdam); Dingemans, T.J. (TU Delft Novel Aerospace Materials; University of North Carolina)","","2019","The ubiquitous biomacromolecule DNA has an axial rigidity persistence length of ~50 nm, driven by its elegant double helical structure. While double and multiple helix structures appear widely in nature, only rarely are these found in synthetic non-chiral macromolecules. Here we report a double helical conformation in the densely charged aromatic polyamide poly(2,2′-disulfonyl-4,4′-benzidine terephthalamide) or PBDT. This double helix macromolecule represents one of the most rigid simple molecular structures known, exhibiting an extremely high axial persistence length (~1 micrometer). We present X-ray diffraction, NMR spectroscopy, and molecular dynamics (MD) simulations that reveal and confirm the double helical conformation. The discovery of this extreme rigidity in combination with high charge density gives insight into the self-assembly of molecular ionic composites with high mechanical modulus (~ 1 GPa) yet with liquid-like ion motions inside, and provides fodder for formation of other 1D-reinforced composites.","","en","journal article","","","","","","","","","","","Novel Aerospace Materials","","",""
"uuid:41cdf59f-f0ad-4d0a-b400-f546660099bb","http://resolver.tudelft.nl/uuid:41cdf59f-f0ad-4d0a-b400-f546660099bb","Incremental Backstepping Sliding Mode Fault-Tolerant Flight Control","Wang, Xuerui (TU Delft Control & Simulation); van Kampen, E. (TU Delft Control & Simulation)","","2019","Fault-tolerant flight control has the potential of improving the aircraft survivability in real life. This paper proposes an Incremental Backstepping Sliding Mode Control (IBSMC) framework for multi-input/output nonlinear strict-feedback systems considering model uncertainties, sudden faults, and external disturbances. This approach is a hybridization of the Sliding Mode Control (SMC) and a reformulated Incremental Backstepping (IBS). By virtue of the benefits contributed by both SMC and IBS, theoretical analyses prove IBSMC has less model dependency and enhanced robustness as compared to backstepping and backstepping hybridized with SMC (BSMC). When applied to an aircraft fault-tolerant control problem, numerical simulations demonstrate IBSMC can passively tolerate a wider range of model uncertainties, sudden actuator faults, and sudden structural damages as compared to backstepping and BSMC, using smooth control inputs with lower gains.","","en","conference paper","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-05","","","Control & Simulation","","",""
"uuid:fbc34ac3-cedf-42be-8d6f-dac1d8cb0a32","http://resolver.tudelft.nl/uuid:fbc34ac3-cedf-42be-8d6f-dac1d8cb0a32","Design of 3D Wireless Power Transfer System Based on 3D Printed Electronics","Hou, T. (TU Delft Mechatronic Design; School of Mechatronic Engineering and Automation); Xu, J. (TU Delft Mechatronic Design); Elkhuizen, W.S. (TU Delft Mechatronic Design); Wang, C.C. (Chinese University of Hong Kong); Jiang, Jiehui (Shanghai Institute for Advanced Communication and Data Science; Shanghai University); Geraedts, Jo M.P. (TU Delft Mechatronic Design); Song, Y. (TU Delft Mechatronic Design)","","2019","2D coil design limits the use of wireless power transfer (WPT) in many products with freeform outer shapes. In this paper, enabled by 3D printed electronics, we propose a systematic approach to design and fabricate 3D coils for WPT. Based on the circular spiral and rectangular spiral patterns, 3D receiver and transmitter coils can be generated on an arbitrarily selected region of a product and its offset, respectively. Mathematical models are proposed to estimate the self-inductance and the mutual-inductance of the 3D arbitrarily shaped coils for 3D WPT. This leads to a new design approach of a 3D WPT system. Several sets of 3D printed WPT systems were designed, simulated, and prototyped to demonstrate the effectiveness of the proposed design approach as well as the mathematical models. The calculation speed of the proposed mathematical models is 30 times faster than the simulation, and compared with the measurement results, the calculation results have mean absolute errors of 2.63% and 4.45% regarding the self- and the mutual-inductance, where the simulation results have mean absolute errors of 1.20% and 2.38%, respectively. Measurements also indicate that with a 5V input, the prototypes are able to deliver 1-watt power at an efficiency ranging between 20.9% and 25.3%. It was concluded that the proposed approach is feasible and promising for designing and manufacturing WPT using 3D printed electronics.","3D coil; 3D printed electronics; design; IPT; WPT; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Mechatronic Design","","",""
"uuid:83c3544e-24db-4fb2-9ebf-e81a3f092b30","http://resolver.tudelft.nl/uuid:83c3544e-24db-4fb2-9ebf-e81a3f092b30","Relationships between mobile phone usage and activity-travel behavior: A review of the literature and an example","Wang, Y. (TU Delft Transport and Planning); Correia, Gonçalo (TU Delft Transport and Planning; Universidade de Coimbra); van Arem, B. (TU Delft Transport and Planning)","Ben-Elia, Eran (editor)","2019","Almost everyone has a mobile phone today. In addition to calls and text messages, people are utilizing mobile apps and websites to connect to the world and explore different content anytime and anywhere. The use of smart phones generates billions of records, including spatiotemporal trajectories, and various mobile phone usage details, such as call duration, and frequency of visiting a certain type of website. Most transportation researchers have only focused on spatiotemporal traces, which represent activity-travel behavior of users. However, it is worth making full use of smart phone data to study how mobile phone usage is related to activity-travel behavior. This chapter first reviews the existing literature on the relevant topics to demonstrate the lack of research on the relationship between mobile internet usage and activity-travel behavior. Based on an 11-day dataset from Shanghai that includes not only spatiotemporal traces but also the frequencies of browsing different categories of mobile internet content (e.g., tourism and finance), we examine several relationships between mobile internet usage and activity-travel behavior.","Activity patterns; Commuting behavior; Location choice; Mobile internet usage; Mobile phone data; Mobile phone usage; Spatiotemporal traces; Travel behavior; Variety seeking","en","book chapter","Elsevier","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2020-02-23","","","Transport and Planning","","",""
"uuid:5cd82d37-fbb2-438b-80a5-45d31e6bc794","http://resolver.tudelft.nl/uuid:5cd82d37-fbb2-438b-80a5-45d31e6bc794","Inconsistencies Among Spectral Robustness Metrics","Wang, X. (TU Delft Mathematical Physics); Feng, Ling (A*STAR Computational Resource Centre (A*CRC)); Kooij, Robert (TU Delft Network Architectures and Services; Singapore University of Technology and Design); Marzo, Jose L. (University of Girona)","Phan, Van Ca (editor); Duong, Trung Q. (editor); Vo, Nguyen-Son (editor)","2019","Network robustness plays a critical role in the proper functioning of modern society. It is common practice to use spectral metrics, to quantify the robustness of networks. In this paper we compare eight different spectral metrics that quantify network robustness. Four of the metrics are derived from the adjacency matrix, the others follow from the Laplacian spectrum. We found that the metrics can give inconsistent indications, when comparing the robustness of different synthetic networks. Then, we calculate and compare the spectral metrics for a number of real-world networks, where inconsistencies still occur, but to a lesser extent. Finally, we indicate how the concept of the R∗-value, a weighted sum of robustness metrics, can be used to resolve the found inconsistencies.","Graph spectra; Graph theory; Inconsistency; Network theory; Robustness metrics","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-11-29","","","Mathematical Physics","","",""
"uuid:d9144886-e99a-49cd-95f4-1aad4da85a0b","http://resolver.tudelft.nl/uuid:d9144886-e99a-49cd-95f4-1aad4da85a0b","Non-pharmacological interventions for people with dementia: Design recommendations from an ergonomics perspective","Wang, G. (TU Delft Applied Ergonomics and Design); Albayrak, A. (TU Delft Applied Ergonomics and Design); Molenbroek, J.F.M. (TU Delft Applied Ergonomics and Design); van der Cammen, T.J.M. (TU Delft Applied Ergonomics and Design)","Bagnara, S. (editor); Tartaglia, R. (editor); Albolino, S. (editor); Alexander, T. (editor); Fujita, Y. (editor)","2019","Non-pharmacological interventions have been applied to manage Behavioural and Psychological Symptoms of Dementia (BPSD). However, these interventions have not been assessed from an ergonomics perspective. Ergonomics has investigated the age-related capability changes in terms of sensory, cognition and movement aspects. This study aims to review the existing non-pharmacological interventions for BPSD targeting nursing home residents and generate design recommendations based on the domain of ergonomics in ageing. The electronic databases MEDLINE, EMBASE, PsycINFO were searched for studies which applied non-pharmacological interventions for treating BPSD in nursing home residents. A total of 67 studies met the inclusion criteria; from which 16 types of interventions were identified. Within these intervention types, the main capabilities required from the interventions for People with Dementia (PwD) were identified. The interventions were then categorized into sensory-, cognition-, and movement-oriented according to the main capabilities. Design recommendations were then generated for the interventions with knowledge from the domain of ergonomics in ageing.","Ageing population; Behavioural and psychological symptoms of dementia; Cognition; Intervention design; Movement; Sensory capabilities","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-02-05","","","Applied Ergonomics and Design","","",""
"uuid:7addebae-e9f5-490e-8e52-f41f43475c3e","http://resolver.tudelft.nl/uuid:7addebae-e9f5-490e-8e52-f41f43475c3e","Characterizing temporal bipartite networks - Sequential- Versus cross-tasking","Peters, Lucas J.J.M. (Student TU Delft); Cai, J. (TU Delft Statistics); Wang, H. (TU Delft Multimedia Computing)","Aiello, Luca Maria (editor); Cherifi, Chantal (editor); Cherifi, Hocine (editor); Lambiotte, Renaud (editor); Lió, Pietro (editor); Rocha, Luis M. (editor)","2019","Temporal bipartite networks that describe how users interact with tasks or items over time have recently become available. Such temporal information allows us to explore user behavior in-depth. We propose two metrics, the relative switch frequency and distraction in time to measure a user’s sequential-tasking level, i.e. to what extent a user interacts with a task consecutively without interacting with other tasks in between. We analyze the sequential-tasking level of users in two real-world networks, an user-project and an user-artist network that record users’ contribution to software projects and users’ playing of musics from diverse artists respectively. We find that users in the user-project network tend to be more sequential-tasking than those in the user-artist network, suggesting a major difference in user behavior when subject to work related and hobby-related tasks. Moreover, we investigate the relation (rank correlation) between the two sequential-tasking measures and another 10 nodal features. Users that interact less frequently or more regularly in time (low deviation in the time interval between two interactions) or with fewer items tend to be more sequential-tasking in the user-project network. No strong correlation has been found in the user-artist network, which limits our ability to identify sequential-tasking users from other user features.","","en","conference paper","Springer","","","","","Accepted author manuscript","","2020-12-05","","","Statistics","","",""
"uuid:09dc1f25-47e7-47df-86b2-c71e0a1b8a85","http://resolver.tudelft.nl/uuid:09dc1f25-47e7-47df-86b2-c71e0a1b8a85","FloodCitiSense: Early Warning Service for Urban Pluvial Floods for and by Citizens and City Authorities","Verbeiren, Boud (Vrije Universiteit Brussel; Brussels Company for Water Management (SBGE/BMWB)); Seyoum, Solomon Dagnachew (Vrije Universiteit Brussel); Lubbad, Ihab (Vrije Universiteit Brussel); Tian, X. (TU Delft Water Resources); ten Veldhuis, Marie-claire (TU Delft Water Resources); Onof, Christian (Imperial College London); Wang, Li Pen (Imperial College London; RainPlusPlus Ltd.); Ochoa-Rodriguez, Susana (RPS Group Plc); Veeckman, Carina (Vrije Universiteit Brussel)","Mannina, Giorgio (editor)","2019","FloodCitiSense aims at developing an urban pluvial flood early warning service for, but also by citizens and city authorities, building upon the state-of-the-art knowledge, methodologies and smart technologies provided by research units and private companies. FloodCitiSense targets the co-creation of this innovative public service in an urban living lab context with all local actors. This service will reduce the vulnerability of urban areas and citizens to pluvial floods, which occur when heavy rainfall exceeds the capacity of the urban drainage system. Due to their fast onset and localized nature, they cause significant damage to the urban environment and are challenging to manage. Monitoring and management of peak events in cities is typically in the hands of local governmental agencies. Citizens most often just play a passive role as people negatively affected by the flooding, despite the fact that they are often the ‘first responders’ and should therefore be actively involved. The FloodCitiSense project aims at integrating crowdsourced hydrological data, collaboratively monitored by local stakeholders, including citizens, making use of low-cost sensors and web-based technologies, into a flood early warning system. This will enable ‘citizens and cities’ to be better prepared for and better respond to urban pluvial floods. Three European pilot cities are targeted: Brussels – Belgium, Rotterdam – The Netherlands and Birmingham – UK.","Citizen science; Flood early warning system; Urban pluvial flooding","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-03-01","","","Water Resources","","",""
"uuid:70fcb01e-7e6a-4748-8f24-d5760e60d29f","http://resolver.tudelft.nl/uuid:70fcb01e-7e6a-4748-8f24-d5760e60d29f","Cumulative learning","Thórisson, Kristinn R. (Reykjavik University); Bieger, J.E. (TU Delft Information and Communication Technology; Reykjavik University); Li, X. (Temple University); Wang, Pei (Temple University)","Hammer, Patrick (editor); Agrawal, Pulin (editor); Goertzel, Ben (editor); Iklé, Matthew (editor)","2019","An important feature of human learning is the ability to continuously accept new information and unify it with existing knowledge, a process that proceeds largely automatically and without catastrophic side-effects. A generally intelligent machine (AGI) should be able to learn a wide range of tasks in a variety of environments. Knowledge acquisition in partially-known and dynamic task-environments cannot happen all-at-once, and AGI-aspiring systems must thus be capable of cumulative learning: efficiently making use of existing knowledge while learning new things, increasing the scope of ability and knowledge incrementally—without catastrophic forgetting or damaging existing skills. Many aspects of such learning have been addressed in artificial intelligence (AI) research, but relatively few examples of cumulative learning have been demonstrated to date and no generally accepted explicit definition exists of this category of learning. Here we provide a general definition of cumulative learning and describe how it relates to other concepts frequently used in the AI literature.","Artificial general intelligence; Autonomous knowledge acquisition; Cumulative learning; Knowledge representation","en","conference paper","Springer","","","","","","","","","","Information and Communication Technology","","",""
"uuid:f3924975-6944-48d9-aba5-df902503ee20","http://resolver.tudelft.nl/uuid:f3924975-6944-48d9-aba5-df902503ee20","Color-Based Proprioception of Soft Actuators Interacting with Objects","Scharff, R.B.N. (TU Delft Materials and Manufacturing); Doornbusch, Rens M. (Student TU Delft); Doubrovski, E.L. (TU Delft Mechatronic Design); Wu, J. (TU Delft Materials and Manufacturing); Geraedts, Jo M.P. (TU Delft Mechatronic Design); Wang, C.C. (TU Delft Materials and Manufacturing; Chinese University of Hong Kong)","","2019","Actuators using soft materials feature a large number of degrees of freedom. This tremendous flexibility allows a soft actuator to passively adapt its shape to the objects under interaction. In this paper, we propose a novel proprioception method for soft actuators during real-time interaction with previously unknown objects. First, we design a color-based sensing structure that instantly translates the inflation of a bellow into changes in color, which are subsequently detected by a miniaturized color sensor. The color sensor is small and, thus, multiple of them can be integrated into soft pneumatic actuators to reflect local deformations. Second, we make use of a feed-forward neural network to reconstruct a multivariate global shape deformation from local color signals. Our results demonstrate that deformations of the actuator during interaction, including sigmoid-like shapes, can be accurately reconstructed. The accurate shape sensing represents a significant step toward closed-loop control of soft robots in unstructured environments.","Color sensor; pneumatic actuator; sensor fusion; shape prediction; soft robotics","en","journal article","","","","","","","","","","","Materials and Manufacturing","","",""
"uuid:b55d70d8-a79e-4060-b1f0-4165ac15e4b3","http://resolver.tudelft.nl/uuid:b55d70d8-a79e-4060-b1f0-4165ac15e4b3","Monitoring sediment transport patterns on an energetic ebb-tidal delta using dual-signature tracers","Pearson, S.G. (TU Delft Coastal Engineering); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Poleykett, Jack (Partrac); Wright, Matthew (Partrac); Black, Kevin (Partrac); Wang, Zhengbing (TU Delft Coastal Engineering)","","2018","","","en","poster","","","","","","","","","","","Coastal Engineering","","",""
"uuid:34b8397c-0204-4617-be6a-ed9576b895c6","http://resolver.tudelft.nl/uuid:34b8397c-0204-4617-be6a-ed9576b895c6","Calibration and validation for the vessel maneuvering prediction (VMP) model using AIS data of vessel encounters","Shu, Y. (TU Delft Transport and Planning); Daamen, W. (TU Delft Transport and Planning); Ligteringen, H. (TU Delft Rivers, Ports, Waterways and Dredging Engineering); Wang, M. (TU Delft Transport and Planning); Hoogendoorn, S.P. (TU Delft Transport and Planning)","","2018","The Vessel Maneuvering Prediction (VMP) model, which was developed in a previous work with the aim of predicting the interaction between vessels in ports and waterways, is optimized in this paper by considering the relative position and vessel size (length and beam). The calibration is carried out using AIS data of overtaking vessels in the port of Rotterdam. The sensitivity analysis of the optimal parameters shows the robustness of the calibrated VMP model. For the validation, the optimal parameters are used to simulate the whole path of overtaken vessels and vessels in head-on encounters. Compared to the AIS data, the validation results show that the different deviations in longitudinal direction range from 33 m to 112 m, which is less than 5% of the waterway stretch. Both the calibration and validation show that the VMP model has the potential to simulate vessel traffic in ports and waterways.","Calibration; Head-on encounter; Overtaking encounter; The VMP model; Validation","en","journal article","","","","","","","","2020-10-06","","Transport and Planning","Transport and Planning","","",""
"uuid:48821553-26e0-4b80-b662-11a120ed6e40","http://resolver.tudelft.nl/uuid:48821553-26e0-4b80-b662-11a120ed6e40","Contractor cooperation mechanism and evolution of the green supply chain in mega projects","Zhu, Jianbo (Nanjing University); Fang, Miao (Nanjing University); Shi, Q. (TU Delft Integral Design & Management; Nanjing University); Wang, Peng (Curtin University; Southwestern University); Li, Qian (Nanjing University)","","2018","The large scale of construction in mega projects leads to significant environmental and socioeconomic impacts; thus, the projects should also exhibit greater social responsibility. Adopting green supply chain management in the construction process is an important way to realize the goal of sustainable development of mega projects. Because the green supply chain behavior during construction is mainly demonstrated by contractors, it is especially important to study the evolutionary trend of their behavior. Thus, to explore the cooperative relationship among contractors, this paper considers a lengthy construction period, multi-agent participation dynamics, and opportunistic behavior-all are key features of mega projects-and establishes an evolutionary game model. Specifically, a replicator dynamic equation is used to describe the long-term effects of the contractor's decisions. Equilibrium determinants are then analyzed and simulated. The results show that the initial probabilities of the two types of contractors (main contractor and subcontractor) demonstrating opportunistic behaviors have a significant effect on the direction of evolution of the mega project. The main contractor, who dominates the subsidy allocation by the government and project owner, should pay attention to maintaining a balance in the income distribution between him or her and the subcontractor. Additionally, there is an optimal distribution coefficient for the subsidy that minimizes the overall probability of opportunistic behavior. This paper provides a point of reference for the decisions of the main contractor and the subcontractor in the green supply chain of mega projects.","Cooperation mechanism; Evolution; Green supply chain; Mega projects","en","journal article","","","","","","","","","","","Integral Design & Management","","",""
"uuid:656c870d-086f-43f2-bc7d-721f1b3da31e","http://resolver.tudelft.nl/uuid:656c870d-086f-43f2-bc7d-721f1b3da31e","Morphodynamic Feedback Loops Control Stable Fringing Flats","Maan, D.C. (TU Delft Coastal Engineering); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Zhu, Q.; Wang, Zhengbing (TU Delft Coastal Engineering)","","2018","We apply a 2-D horizontal process-based model (Delft3D) to study the feedback mechanisms that control the long-term evolution of a fringing intertidal flat in the Western Scheldt Estuary. The hydrodynamic model is validated using a comparison with measurements on the intertidal flat and the sediment transport module is calibrated against long-term morphology data. First, the processes that lead to net sediment exchange between channel and flat are studied. Then, long-term simulations are performed and the dependency of sediment fluxes on the tidal flat bathymetry, and the corresponding morphodynamic feedback mechanisms are explained. In the long run, relatively stable states can be approached, which are shown to be typical for wave-dominated fringing mudflats. The system behavior can be explained by the typical feedback mechanisms between the intertidal bathymetry and the hydrodynamic forces on the flat. In the subtidal domain, the impact of small (5–10 cm) wind waves increases with a rising elevation due to decreasing water depths. In the intertidal domain, the wave impact
increases with increasing cross-sectional slope due to wave shoaling. These relationships result in negative (stabilizing) morphodynamic feedback loops. The tidal current velocities and tide-induced bed shear stresses, on the other hand, are largely determined by the typical horizontal geometry. A stabilizing
feedback loop fails, so that there is no trend toward an equilibrium state in the absence of wind waves.","","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:223d4465-39b6-423f-8713-eef3625f1eaf","http://resolver.tudelft.nl/uuid:223d4465-39b6-423f-8713-eef3625f1eaf","Beyond the orthogonal: On the influence of build orientation on fatigue crack growth in SLM Ti-6Al-4V","Rans, C.D. (TU Delft Structural Integrity & Composites); Michielssen, J. (TU Delft Education AE); Walker, M.S. (TU Delft Structural Integrity & Composites); Wang, W. (TU Delft Structural Integrity & Composites); Hoen-Velterop, Ludmila ’t (Royal Netherlands Aerospace Centre NLR)","","2018","A challenge in developing an in-depth understanding of the crack growth resistance of Additively Manufactured materials is the fact that their mechanical properties have been shown to be both process and part-geometry dependent. Up to now, no studies have investigated the influence of off-axis (beyond the three orthogonal build orientations) orientations on the fatigue crack growth behaviour of selective laser melted Ti-6Al-4V. Furthermore, the widespread use of compact tension specimens for investigating the material behaviour generates data more suitable for plane-strain conditions, rather than the plane-stress state which is more applicable to many lightweight aerospace structures. To address this gap in knowledge, a comprehensive study was carried out to investigate the influence of off-axis build direction in thin SLM Ti-6Al-4V plates, with a focus on the influence of columnar grain orientation on the fatigue crack growth behaviour. It was found that although a macroscopic columnar grain structure is visible on the specimens, it had no discernible influence on the crack growth resistance when the specimen had undergone a stress relieving or HIP heat treatment.","Additive manufacturing; Anisotropy; Fatigue crack growth; Selective laser melting; Titanium","en","journal article","","","","","","","","2020-07-10","","","Structural Integrity & Composites","","",""
"uuid:50a13d17-79b3-4ced-bf62-9ded968d64dd","http://resolver.tudelft.nl/uuid:50a13d17-79b3-4ced-bf62-9ded968d64dd","Extracting individual bricks from a laser scan point cloud of an unorganized pile of bricks","Shen, Y. (TU Delft Optical and Laser Remote Sensing; Hohai University); Lindenbergh, R.C. (TU Delft Optical and Laser Remote Sensing); Wang, Jinguo (Hohai University); Ferreira, Vagner G. (Hohai University)","","2018","Bricks are the vital component of most masonry structures. Their maintenance is critical to the protection of masonry buildings. Terrestrial Light Detection and Ranging (TLidar) systems provide massive point cloud data in an accurate and fast way. TLidar enables us to sample and store the state of a brick surface in a practical way. This article aims to extract individual bricks from an unorganized pile of bricks sampled by a dense point cloud. The method automatically segments and models the individual bricks. The methodology is divided into five main steps: Filter needless points, brick boundary points removal, coarse segmentation using 3D component analysis, planar segmentation and grouping, and brick reconstruction. A novel voting scheme is used to segment the planar patches in an effective way. Brick reconstruction is based on the geometry of single brick and its corresponding nominal size (length, width and height). The number of bricks reconstructed is around 75%. An accuracy assessment is performed by comparing 3D coordinates of the reconstructed vertices to the manually picked vertices. The standard deviations of differences along x, y and z axes are 4.55 mm, 4.53 mm and 4.60 mm, respectively. The comparison results indicate that the accuracy of reconstruction based on the introduced methodology is high and reliable. The work presented in this paper provides a theoretical basis and reference for large scene applications in brick-like structures. Meanwhile, the high-accuracy brick reconstruction lays the foundation for further brick displacement estimation.","3D connected component analysis; Accuracy assessment; Brick reconstruction; Planar segmentation; Terrestrial LiDAR; Unorganized bricks","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:f228ab63-c420-4d71-a643-3fab728aa829","http://resolver.tudelft.nl/uuid:f228ab63-c420-4d71-a643-3fab728aa829","Unravelling effects of cooperative adaptive cruise control deactivation on traffic flow characteristics at merging bottlenecks","Xiao, L. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); Schakel, W.J. (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning)","","2018","Cooperative Adaptive Cruise Control (CACC) systems have the potential to increase roadway capacity and mitigate traffic congestion thanks to the short following distance enabled by inter-vehicle communication. However, due to limitations in acceleration and deceleration capabilities of CACC systems, deactivation and switch to ACC or human-driven mode will take place when conditions are outside the operational design domain. Given the lack of elaborate models on this interaction, existing CACC traffic flow models have not yet been able to reproduce realistic CACC vehicle behaviour and pay little attention to the influence of system deactivation on traffic flow at bottlenecks. This study aims to gain insights into the influence of CACC on highway operations at merging bottlenecks by using a realistic CACC model that captures driver-system interactions and string length limits. We conduct systematic traffic simulations for various CACC market penetration rates (MPR) to derive free-flow capacity and queue discharge rate of the merging section and compare these to the capacity of a homogeneous pipeline section. The results show that an increased CACC MPR can indeed increase the roadway capacity. However, the resulting capacity in the merging bottleneck is much lower than the pipeline capacity and capacity drop persists in bottleneck scenarios at all CACC MPR levels. It is also found that CACC increases flow heterogeneity due to the switch among different operation modes. A microscopic investigation of the CACC operational mode and trajectories reveals a close relation between CACC deactivation, traffic congestion and flow heterogeneity.","Authority transitions; Capacity drop; Cooperative Adaptive Cruise Control; Merging; Microscopic simulation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-03-12","","","Transport and Planning","","",""
"uuid:9d79cf6d-19a5-4f0f-a01e-6573f8e1b2ce","http://resolver.tudelft.nl/uuid:9d79cf6d-19a5-4f0f-a01e-6573f8e1b2ce","Linearity Research of A CMOS Image Sensor","Wang, F. (TU Delft Electronic Instrumentation)","Theuwissen, A.J.P.A.M. (promotor); Delft University of Technology (degree granting institution)","2018","This thesis provides a thorough analysis of the linearity characteristics of a CMOS image sensor. Firstly, this thesis analyzes the factors that cause the nonlinearity of the image sensors. These factors are then verified by simulation results of a proposed behavioral model and the measurements in a prototype chip. Secondly, different techniques are presented to improve the linearity of the whole imaging system; and the effectiveness of these techniques is further confirmed by measurement results of several test chips.","","en","doctoral thesis","","978-94-028-1233-6","","","","","","","","","Electronic Instrumentation","","",""
"uuid:885c033a-4d5b-4cf6-9440-b9552e45fb17","http://resolver.tudelft.nl/uuid:885c033a-4d5b-4cf6-9440-b9552e45fb17","Digital Cartographic Model of 3D Cadastre: An Initial Design and Implementation","Wang, Chen; Yu, Chang-bin","","2018","Despite the abundant research discoveries in 3D cadastre visualization, there still lacks a synthesis method of concreate symbology instructions and 3D graphical content as an easy entry for designers, implementors, and visualization systems. In cartography domain, introducing DCM (Digital Cartographic Model) on top of DLM (Digital Landscape Model) is a method that could enable unambiguous depiction of portrayal and improve the visualization interoperability. Currently, no investigation has explored the applicability of this method in 3D cadastre visualization. The aim of this research is to evaluate the applicability of using DCM for 3D cadastre visualization regarding symbology encoding, graphic content creation, and 3D content exchange. In this research, the 3D cadastre DCM contains 1, a 3D symbology encoding module to structurally describe the employment of 3D design features; 2, a 3D graphic content module to represent the symbology result. We first investigated the current 3D cadastre visualization features. According to these features, we then designed a tentative 3D symbology encoding model and select COLLADA and glTF as 3D content models. We invited scholar and student participants to learn, use, and judge 3D SE for the description of 3D cadastre visualization instructions. We constructed a prototypical program that can read 3D symbology encoding and then convert DLM data automatically to COLLADA and glTF encoded 3D graphic content. Finally, we export the COLLADA and glTF files to multiple visualization platforms and evaluate the visualization result. The work of this research shows that applying DCM in 3D cadastre is applicable and improves the visualization interoperability. It enables structured symbology description, automatic graphic content creation, and promotes the 3D content exchange. Current design and implementation are still at an early stage. It may have improvement in multiple parts, including the more advanced feature filtering of XML based data, and the finer rendering control.","digital cartographic model; 3D cadastre; visualization; symbology","en","conference paper","","","","","","","","","","","","","",""
"uuid:ec81594a-8c32-4008-b71a-7ed2338fe92d","http://resolver.tudelft.nl/uuid:ec81594a-8c32-4008-b71a-7ed2338fe92d","Australia-first high-precision positioning results with new Japanese QZSS regional satellite system","Zaminpardaz, S. (TU Delft Mathematical Geodesy and Positioning; Curtin University); Wang, Kan (Curtin University); Teunissen, P.J.G. (TU Delft Mathematical Geodesy and Positioning; Curtin University)","","2018","The Japanese Quasi-Zenith Satellite System (QZSS) has recently (October 2017) reached its first 4-satellite constellation. In this contribution, the standalone performance of this 4-satellite QZSS constellation is assessed by means of its triple-frequency (L1 + L2 + L5) real-time kinematic (RTK) integer ambiguity resolution and precise positioning capabilities. Our analyses are carried out for data collected in Perth, Australia, and include a study of the noise characteristics of the QZSS code and phase data, particularly concerning their precision, time correlation and multipath. Our results show that while the phase observations on different frequencies are of similar precision, the code observations on different frequencies show considerably different precisions and can be ordered, from high to low, as L5, L2 and L1. As to positioning and ambiguity resolution, we demonstrate that the Position Dilution Of Precision (PDOP) and the Ambiguity Dilution Of Precision (ADOP) exhibit complementary characteristics, both of which are important for predicting precise positioning capabilities. We show that despite the large PDOPs, the ADOPs are sufficiently small to indicate (almost) instantaneous successful ambiguity resolution. This is confirmed by our empirical data analyses, demonstrating that instantaneous ambiguity resolution is feasible, despite the relatively poor 4-satellite receiver-to-satellite positioning geometry over Australia, thus showing that already now centimeter-level stand-alone QZSS positioning is possible with the current 4-satellite constellation (February–March 2018).","Ambiguity resolution; Multipath; QZSS; RTK; Stochastic properties; Time correlation","en","journal article","","","","","","","","","","","Mathematical Geodesy and Positioning","","",""
"uuid:d5fb6947-dc54-424f-a3b0-43af4c75dd9d","http://resolver.tudelft.nl/uuid:d5fb6947-dc54-424f-a3b0-43af4c75dd9d","International benchmarking of terrestrial laser scanning approaches for forest inventories","Liang, Xinlian (Finnish Geospatial Research Institute); Hyyppä, Juha (Finnish Geospatial Research Institute); Kaartinen, Harri (Finnish Geospatial Research Institute; University of Turku); Lehtomäki, Matti (Finnish Geospatial Research Institute); Pyörälä, Jiri (Finnish Geospatial Research Institute; University of Helsinki); Pfeifer, Norbert (Technische Universität Wien); Holopainen, Markus (Finnish Geospatial Research Institute; University of Helsinki); Wang, Di (Technische Universität Wien); Wang, J. (TU Delft Optical and Laser Remote Sensing)","","2018","The last two decades have witnessed increasing awareness of the potential of terrestrial laser scanning (TLS) in forest applications in both public and commercial sectors, along with tremendous research efforts and progress. It is time to inspect the achievements of and the remaining barriers to TLS-based forest investigations, so further research and application are clearly orientated in operational uses of TLS. In such context, the international TLS benchmarking project was launched in 2014 by the European Spatial Data Research Organization and coordinated by the Finnish Geospatial Research Institute. The main objectives of this benchmarking study are to evaluate the potential of applying TLS in characterizing forests, to clarify the strengths and the weaknesses of TLS as a measure of forest digitization, and to reveal the capability of recent algorithms for tree-attribute extraction. The project is designed to benchmark the TLS algorithms by processing identical TLS datasets for a standardized set of forest attribute criteria and by evaluating the results through a common procedure respecting reliable references. Benchmarking results reflect large variances in estimating accuracies, which were unveiled through the 18 compared algorithms and through the evaluation framework, i.e., forest complexity categories, TLS data acquisition approaches, tree attributes and evaluation procedures. The evaluation framework includes three new criteria proposed in this benchmarking and the algorithm performances are investigated through combining two or more criteria (e.g., the accuracy of the individual tree attributes are inspected in conjunction with plot-level completeness) in order to reveal algorithms’ overall performance. The results also reveal some best available forest attribute estimates at this time, which clarify the status quo of TLS-based forest investigations. Some results are well expected, while some are new, e.g., the variances of estimating accuracies between single-/multi-scan, the principle of the algorithm designs and the possibility of a computer outperforming human operation. With single-scan data, i.e., one hemispherical scan per plot, most of the recent algorithms are capable of achieving stem detection with approximately 75% completeness and 90% correctness in the easy forest stands (easy plots: 600 stems/ha, 20 cm mean DBH). The detection rate decreases when the stem density increases and the average DBH decreases, i.e., 60% completeness with 90% correctness (medium plots: 1000 stem/ha, 15 cm mean DBH) and 30% completeness with 90% correctness (difficult plots: 2000 stems/ha, 10 cm mean DBH). The application of the multi-scan approach, i.e., five scans per plot at the center and four quadrant angles, is more effective in complex stands, increasing the completeness to approximately 90% for medium plots and to approximately 70% for difficult plots, with almost 100% correctness. The results of this benchmarking also show that the TLS-based approaches can provide the estimates of the DBH and the stem curve at a 1–2 cm accuracy that are close to what is required in practical applications, e.g., national forest inventories (NFIs). In terms of algorithm development, a high level of automation is a commonly shared standard, but a bottleneck occurs at stem detection and tree height estimation, especially in multilayer and dense forest stands. The greatest challenge is that even with the multi-scan approach, it is still hard to completely and accurately record stems of all trees in a plot due to the occlusion effects of the trees and bushes in forests. Future development must address the redundant yet incomplete point clouds of forest sample plots and recognize trees more accurately and efficiently. It is worth noting that TLS currently provides the best quality terrestrial point clouds in comparison with all other technologies, meaning that all the benchmarks labeled in this paper can also serve as a reference for other terrestrial point clouds sources.","Benchmarking; Forest; Modeling; Point cloud; State-of-the-art; Terrestrial laser scanning; TLS","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:c6ac0c9f-6a92-447a-8e22-62289059d4b3","http://resolver.tudelft.nl/uuid:c6ac0c9f-6a92-447a-8e22-62289059d4b3","Non-Newtonian behaviors of crumb rubber-modified bituminous binders","Wang, H. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Apostolidis, P. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Petroleum Institute)","","2018","Crumb rubber-modified bitumen (CRMB) has been utilized in the asphalt paving industry for decades due to its various benefits. The complex interaction between bitumen and crumb rubber as well as the addition of warm-mix additives makes the typical laws of Newtonian fluids insufficient to describe the behaviors of highly modified bituminous binders. To systematically explore the non-Newtonian behaviors of CRMB, a dynamic shear rheometer was utilized to apply shear loading on the samples at various temperatures and shear rates. Results show that the viscosity of different binders are highly temperature- and shear rate-dependent, while highly modified binders exhibit more obvious shear-thinning behaviors at certain temperatures. With the help of zero shear viscosity and yield stress, the shear-thinning behaviors of non-Newtonian binders can be sufficiently characterized. The Arrhenius equation is invalid to describe viscosity-temperature characteristics of bitumen in the non-Newtonian region. A second-order polynomial function was proposed to characterize the viscosity-temperature dependence with a high correlation degree.","Bitumen; Crumb rubber modifier (CRM); Non-Newtonian behavior; Viscosity; Warm mix asphalt","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:38c73d4d-ab85-43a3-a2aa-b66ab4adfbe2","http://resolver.tudelft.nl/uuid:38c73d4d-ab85-43a3-a2aa-b66ab4adfbe2","Impact of long-term salinity exposure in anaerobic membrane bioreactors treating phenolic wastewater: Performance robustness and endured microbial community","Muñoz Sierra, Julian (TU Delft Sanitary Engineering); Oosterkamp, M.J. (TU Delft Sanitary Engineering); Wang, W.W. (TU Delft Sanitary Engineering; Hefei University of Technology); Spanjers, H. (TU Delft Sanitary Engineering); van Lier, J.B. (TU Delft Sanitary Engineering)","","2018","Industrial wastewaters are becoming increasingly associated with extreme conditions such as the presence of refractory compounds and high salinity that adversely affect biomass retention or reduce biological activity. Hence, this study evaluated the impact of long-term salinity increase to 20 gNa+.L−1 on the bioconversion performance and microbial community composition in anaerobic membrane bioreactors treating phenolic wastewater. Phenol removal efficiency of up to 99.9% was achieved at 14 gNa+.L−1. Phenol conversion rates of 5.1 mgPh.gVSS−1.d−1, 4.7 mgPh.gVSS−1.d−1, and 11.7 mgPh.gVSS−1.d−1 were obtained at 16 gNa+.L−1,18 gNa+.L−1 and 20 gNa+.L−1, respectively. The AnMBR's performance was not affected by short-term step-wise salinity fluctuations of 2 gNa+.L−1 in the last phase of the experiment. It was also demonstrated in batch tests that the COD removal and methane production rate were higher at a K+:Na+ ratio of 0.05, indicating the importance of potassium to maintain the methanogenic activity. The salinity increase adversely affected the transmembrane pressure likely due to a particle size decrease from 185 μm at 14 gNa+.L−1 to 16 μm at 20 gNa+.L−1. Microbial community was dominated by bacteria belonging to the Clostridium genus and archaea by Methanobacterium and Methanosaeta genus. Syntrophic phenol degraders, such as Pelotomaculum genus were found to be increased when the maximum phenol conversion rate was attained at 20 gNa+.L−1. Overall, the observed robustness of the AnMBR performance indicated an endured microbial community to salinity changes in the range of the sodium concentrations applied.","AnMBR; Microbial community; Phenol; Salinity; Sodium; Wastewater treatment","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:86bb89a5-a0a2-40a2-94dd-c1419667a0ec","http://resolver.tudelft.nl/uuid:86bb89a5-a0a2-40a2-94dd-c1419667a0ec","Achieving economically sustainable subcontracting through the hotelling model by considering the spillover effect","Zhu, Jianbo (Nanjing University; Curtin University); Shi, Q. (TU Delft Integral Design & Management; Nanjing University); Wu, Peng (Curtin University); Sheng, Zhaohan (Nanjing University); Wang, Xiangyu (Chongqing Normal University; Kyung Hee University)","","2018","In the process of internationalization of construction contractors, international enterprises as main contractors (IMC) need to consider whether part of the contract should be subcontracted to local subcontractors (LSC) to gain a competitive advantage when competing with local main contractors (LMC). The involvement of local subcontractors can usually help reduce cost through the cost spillover effect. However, it should be noted that the share of local subcontractors with local main contractors with an inferior quality may lead to quality spillover. The Hotelling model is therefore adopted to investigate the subcontracting decisions of main contractors considering both cost and quality spillover effects. Many scenarios are simulated and the results show that LMCs with inferior quality can always choose the subcontracting strategy to obtain increased profit regardless of the strategy that IMCs adopt. On the other hand, IMCs need to balance the cost spillover of subcontracting and the quality spillover for improving the quality level of LSCs. The results are useful for contractors to make decisions that are relevant to the adoption of subcontracting strategies to obtain competitive advantages.","Decision making; Hotelling model; Internationalization; Spillover effect; Subcontracting","en","journal article","","","","","","","","","","","Integral Design & Management","","",""
"uuid:a60d1d10-4abb-4177-97b8-7f637984d7b8","http://resolver.tudelft.nl/uuid:a60d1d10-4abb-4177-97b8-7f637984d7b8","NOx reduction in the Di-Air system over noble metal promoted ceria","Wang, Y. (TU Delft ChemE/Catalysis Engineering); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering); Makkee, M. (TU Delft ChemE/Catalysis Engineering)","","2018","In this study, the role of the noble metals Pt and Rh (0.5 wt.%) for the selective reduction of NO into N2 is evaluated by the transient TAP technique and in-situ spectroscopy using a commercial stable ceria support (denoted as CZ) and applying isotopically labelled 15NO and 18O2. The transient operation was mimicked by multi-pulse oxidation (using O2 or NO) and reduction cycles (using CO, H2, C3H6 and C3H8), while following quantitatively the catalyst and reactants response. Pt and Rh significantly lowered the temperature of CZ reduction. CO and H2 only reduce the surface of CZ, while a 2.5 times deeper reduction was achieved by the hydrocarbons C3H6 and C3H8, removing also lattice oxygen. Pt and Rh also promoted carbon deposition after surface reduction. Rh was a more active promoter than Pt, while propene was more reactive than propane over both metals. During the NO reduction the pre-reduced CZ support became gradually re-oxidised and after filling 70–80% of the oxygen vacancies the NO started to appear in the product mixture. In the presence of carbon deposits the lattice oxygen of the CZ reacted with the carbon keeping the CZ in a reduced state, extending the NO decomposition process as long as the carbon was present. The reduction of NO over pre-reduced noble metal/CZ showed a selective formation N2, while N2O and NO2 were never observed. During the NO reduction process some unidentified N-species remained on the catalyst, the amount depending on the type of catalyst, but finally all nitrogen was released as N2. The presence of the noble metal led less unidentified N-species on the CZ surface and to a faster N2 formation rate than that over the bare CZ.","Ceria; FT-IR; Noble metal; Raman; Selective NO reduction; TAP","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:855bd3ac-ab7c-4d81-b2b5-3be74b0c7093","http://resolver.tudelft.nl/uuid:855bd3ac-ab7c-4d81-b2b5-3be74b0c7093","Theoretical analysis of fatigue failure in mechanically fastened Fibre Metal Laminate joints containing multiple cracks","Wang, W. (TU Delft Structural Integrity & Composites); Rans, C.D. (TU Delft Structural Integrity & Composites); Benedictus, R. (TU Delft Aerospace Structures & Materials; TU Delft Structural Integrity & Composites)","","2018","Mechanically fastened joints are susceptible to the presence of multiple-site damage (MSD) cracks in the critical fastener row. Different from the MSD growth in joints consisting of metallic substrates, the two coupled metal crack growth and interfacial delamination propagation failure mechanisms in Fibre Metal Laminates (FMLs) make the prediction of fatigue behaviour in FML joints with MSD scenario burdensome and impractical when considering all factors influencing the fatigue performance. This paper presents a theoretical study on the MSD crack growth behaviour in mechanically fastened FML joints with a focus of modelling the effects of bearing and bypass loads. The proposed model in this paper is built upon analytical models dealing with MSD growth in flat FML panels and single crack growth in FML panels subjected to a combined tension-pin loading case. This model would be particularly useful for symmetric FML joints where no secondary bending effects present. A deliberately designed symmetric FML joint was tested to validate the proposed model. The model captures the rapid crack growth in the vicinity of fastener holes due to bearing stresses and crack acceleration due to the interaction of cracks. It is identified that the load redistribution between intact fastener rows and the cracked fastener row accelerates crack growth with crack length. The effects of secondary bending stresses in FML joints on the crack growth behaviour is extensively discussed. The performance of the proposed model for single lap FML joints is also examined using test data from open literature. It is found that the proposed model provides a conservative prediction for the tested single shear lap FML joint from open literature.","Crack growth acceleration; Fibre Metal Laminates; Load redistribution mechanism; Mechanically fastened joints; MSD","en","journal article","","","","","","","","2020-04-30","","Aerospace Structures & Materials","Structural Integrity & Composites","","",""
"uuid:c484eb96-694c-456c-91d7-704facf82834","http://resolver.tudelft.nl/uuid:c484eb96-694c-456c-91d7-704facf82834","Corrective countermeasure for track transition zones in railways: Adjustable fastener","Wang, Haoyu (TU Delft Railway Engineering); Markine, V.L. (TU Delft Railway Engineering)","","2018","Transition zones in railway tracks are the locations with considerable variation in the vertical stiffness of supporting structures. Typically, they are located near engineering structures, such as bridges, culverts, tunnels and level crossings. In such locations, the variation of the vertical stiffness and the differential track settlement result in amplification of the dynamic forces acting on the track. This amplification contributes to the degradation process of ballast and subgrade, ultimately resulting in the increase of maintenance costs. The paper studies a corrective countermeasure that can mitigate the track degradation in transition zones when differential settlement appears. The countermeasure is the adjustable rail fastener and its working principle is to eliminate the gap under hanging sleepers by adjusting the shims (height of the fastener). The adjustable fasteners are first tested on three transition zones, wherein the adjusted heights of fasteners (accumulated voiding) are recorded after the 2-month and 5-month operation. The test results show the adjustable fasteners are effective to mitigate the track degradation in the transition zones. The effect of the adjustable fasteners on the dynamic behaviour of transition zones is analysed using the FE method. The results show that the adjustable fasteners are effective to reduce the amplification of wheel forces, achieve a better stress distribution in ballast, and decrease the normal stresses in rails in transition zones. Parametric studies are also performed to study the applicability of the adjustable fasteners.","Adjustable fasteners; Corrective countermeasures; Finite element method; Railway track modelling; Transition zone","en","journal article","","","","","","","","2020-05-16","","","Railway Engineering","","",""
"uuid:391ada66-d4a5-49a1-b56c-c1477aafdf60","http://resolver.tudelft.nl/uuid:391ada66-d4a5-49a1-b56c-c1477aafdf60","Evolving wastewater infrastructure paradigm to enhance harmony with nature","Wang, Xu (Chinese Academy of Sciences; University of Exeter); Daigger, Glen (University of Michigan); Lee, Duu Jong (National Taiwan University of Science and Technology; National Taiwan University); Liu, Junxin (Chinese Academy of Sciences); Ren, Nan Qi (Harbin Institute of Technology); Qu, Jiuhui (Chinese Academy of Sciences; Tsinghua University); Liu, G. (TU Delft Sanitary Engineering); Butler, David (University of Exeter)","","2018","Restoring and improving harmony between human activities and nature are essential to human well-being and survival. The role of wastewater infrastructure is evolving toward resource recovery to address this challenge. Yet, existing design approaches for wastewater systems focus merely on technological aspects of these systems. If system design could take advantage of natural ecological processes, it could ensure infrastructure development within ecological constraints and maximize other benefits. To test this hypothesis, we illustrate a data-driven, systems-level approach that couples natural ecosystems and the services they deliver to explore how sustainability principles could be embedded into the life phases of wastewater systems. We show that our design could produce outcomes vastly superior to those of conventional paradigms that focus on technologies alone, by enabling high-level recovery of both energy and materials and providing substantial benefits to offset a host of unintended environmental effects. This integrative study advances our understanding and suggests approaches for regaining a balance between satisfying human demands and maintaining ecosystems.","","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:4e70daa3-92a7-49a2-b7ee-6c9b32f9dad9","http://resolver.tudelft.nl/uuid:4e70daa3-92a7-49a2-b7ee-6c9b32f9dad9","Five-frequency Galileo long-baseline ambiguity resolution with multipath mitigation","Wang, Kan (Curtin University); Khodabandeh, Amir (Curtin University; University of New South Wales); Teunissen, P.J.G. (TU Delft Mathematical Geodesy and Positioning; Curtin University)","","2018","For long-baseline over several hundreds of kilometers, the ionospheric delays that cannot be fully removed by differencing observations between receivers hampers rapid ambiguity resolution. Compared with forming ionospheric-free linear combination using dual- or triple-frequency observations, estimating ionospheric delays using uncombined observations keeps all the information of the observations and allows extension of the strategy to any number of frequencies. As the number of frequencies has increased for the various GNSSs, it is possible to study long-baseline ambiguity resolution performance using up to five frequencies with uncombined observations. We make use of real Galileo observations on five frequencies with a sampling interval of 1 s. Two long baselines continuously receiving signals from six Galileo satellites during corresponding test time intervals were processed to study the formal and empirical ambiguity success rates in case of full ambiguity resolution (FAR). The multipath effects are mitigated using the measurements of another day when the constellation repeats. Compared to the results using multipath-uncorrected Galileo observations, it is found that the multipath mitigation plays an important role in improving the empirical ambiguity success rates. A high number of frequencies are also found to be helpful to achieve high ambiguity success rate within a short time. Using multipath-uncorrected observations on two, three, four and five frequencies, the mean empirical success rates are found to be about 73, 88, 91, and 95% at 10 s, respectively, while the values are increased to higher than 86, 95, 98, and 99% after mitigating the multipath effects.","Ambiguity resolution; Five frequencies; Galileo; Long-baseline","en","journal article","","","","","","","","","","","Mathematical Geodesy and Positioning","","",""
"uuid:9782f79e-3612-4f87-97bd-1944c337e420","http://resolver.tudelft.nl/uuid:9782f79e-3612-4f87-97bd-1944c337e420","Molecular-Scale Hybrid Membranes Derived from Metal-Organic Polyhedra for Gas Separation","Liu, X. (TU Delft ChemE/Catalysis Engineering); Wang, X. (TU Delft ChemE/Catalysis Engineering); Bavykina, A.V. (King Abdullah University of Science and Technology); Chu, L. (TU Delft OLD ChemE/Organic Materials and Interfaces); Shan, M. (TU Delft ChemE/Catalysis Engineering); Sabetghadam, Anahid (Student TU Delft); Miro, H. (TU Delft QN/Kavli Nanolab Delft; Kavli institute of nanoscience Delft); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering); Gascon, Jorge (TU Delft ChemE/Catalysis Engineering; King Abdullah University of Science and Technology)","","2018","The preparation and the performance of mixed matrix membranes based on metal-organic polyhedra (MOPs) are reported. MOP fillers can be dispersed as discrete molecular units (average 9 nm in diameter) when low filler cargos are used. In spite of the low doping amount (1.6 wt %), a large performance enhancement in permeability, aging resistance, and selectivity can be achieved. We rationalize this effect on the basis of the large surface to volume ratio of the filler, which leads to excellent dispersion at low concentrations and thus alters polymer packing. Although membranes based only on the polymer component age quickly with time, the performance of the resulting MOP-containing membranes meets the commercial target for postcombustion CO2 capture for more than 100 days.","cage; gas separation; hybrid membrane; metal-organic polyhedron; molecular scale","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:508646a5-50c4-475c-b8c4-9d6f879a57b1","http://resolver.tudelft.nl/uuid:508646a5-50c4-475c-b8c4-9d6f879a57b1","Biological performance and sludge filterability of anaerobic membrane bioreactors under nitrogen limited and supplied conditions","Dereli, R.K. (TU Delft Sanitary Engineering; Istanbul Technical University); Wang, Xiaofei (New University of Lisbon); van der Zee, F. (Veolia Water Technologies); van Lier, J.B. (TU Delft Sanitary Engineering)","","2018","The impact of nitrogen on biological performance and sludge filterability of anaerobic membrane bioreactors was investigated in two lab-scale cross-flow anaerobic membrane bioreactors that were fed with cheese whey at two different COD:TKN ratios (50 and 190). Nitrogen deprivation adversely affected the biological treatment performance and reactor stability, as indicated by volatile fatty acids accumulation. On the other hand, nitrogen (urea) supplementation resulted in a reduced sludge median particle size and decreased sludge filterability. Standard filterability parameters such as capillary suction time and specific resistance to filtration tended to rapidly increase in the nitrogen supplemented reactor. The critical fluxes in the nitrogen limited and supplemented reactors were 20 and 9 L m−2 h−1, respectively. The rapid deterioration of sludge filterability under nitrogen supplemented conditions was attributed to abundant growth of dispersed biomass. Thus, the COD:TKN ratio of wastewater affected both bioconversion and filterability performance in the anaerobic membrane bioreactors.","Anaerobic membrane bioreactor; Cheese whey; COD:TKN ratio; Filterability; Nitrogen","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-09-07","","","Sanitary Engineering","","",""
"uuid:bc9f6b58-98f8-4eeb-ac89-49c3ba70e2a1","http://resolver.tudelft.nl/uuid:bc9f6b58-98f8-4eeb-ac89-49c3ba70e2a1","Pareto-based maintenance decisions for regional railways with uncertain weld conditions using the Hilbert spectrum of axle box acceleration","Nunez, Alfredo (TU Delft Railway Engineering); Jamshidi, A. (TU Delft Railway Engineering); Wang, H. (TU Delft Railway Engineering)","","2018","This paper presents a Pareto-based maintenance decision system for rail welds in a regional railway network. Weld health condition data are collected using a train in operation. A Hilbert spectrum-based approach is used for data processing to detect and assess the weld quality based on multiple registered dynamic responses in the axle box acceleration measurements. The assessment of the welds is stochastic in nature and variant over time, so a set of robust and predictive key performance indicators is defined to capture the weld degradation dynamics during a given maintenance period. Using a scenario-based approach, two objective functions are defined, performance and the number of weld replacements. Evolutionary multi-objective optimization is employed to optimize the objective functions so that the trade-offs between performance and cost support decision-making for railway network maintenance. The results of the proposed methodology show that the infrastructure manager can localize field inspections and maintenance efforts on the area with the most critical welds. To showcase the capability of the proposed methodology, measurements from a regional railway network in Transylvania, Romania are employed.","Acceleration; Acceleration measurements; Axles; Degradation; Evolutionary multi-objective optimization; Maintenance; Maintenance engineering; Rail transportation; Rails; Railway infrastructure; Welding","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-12-15","","","Railway Engineering","","",""
"uuid:d093f187-9e76-4f96-8635-e5593c621170","http://resolver.tudelft.nl/uuid:d093f187-9e76-4f96-8635-e5593c621170","Infrastructure assisted adaptive driving to stabilise heterogeneous vehicle strings","Wang, M. (TU Delft Transport and Planning)","","2018","Literature has shown potentials of Connected/Cooperative Automated Vehicles (CAVs) in improving highway operations, especially on roadway capacity and flow stability. However, benefits were also shown to be negligible at low market penetration rates. This work develops a novel adaptive driving strategy for CAVs to stabilise heterogeneous vehicle strings by controlling one CAV under vehicle-to-infrastructure (V2I) communications. Assumed is a roadside system with V2I communications, which receives control parameters of the CAV in the string and estimates parameters imperfectly of non-connected automated vehicles. It determines the adaptive control parameters (e.g. desired time gap and feedback gains) of the CAV if a downstream disturbance is identified and sends them to the CAV. The CAV changes its behaviour based on the adaptive parameters commanded by the roadside system to suppress the disturbance. The proposed adaptive driving strategy is based on string stability analysis of heterogeneous vehicle strings. To this end, linearised vehicle dynamics model and control law are used in the controller parametrisation and Laplace transform of the speed and gap error dynamics in time domain to frequency domain enables the determination of sufficient string stability criteria of heterogeneous strings. The analytical string stability conditions give new insights into automated vehicular string stability properties in relation to the system properties of time delays and controller design parameters of feedback gains and desired time gap. It further allows the quantification of a stability margin, which is subsequently used to adapt the feedback control gains and desired time gap of the CAV to suppress the amplification of gap and speed errors through the string. Analytical results are verified via systematic simulation of both homogeneous and heterogeneous strings. Simulation demonstrates the predictive power of the analytical string stability conditions. The performance of the adaptive driving strategy under V2I cooperation is tested in simulation. Results show that even the estimation of control parameters of non-connected automated vehicles are imperfect and there is mismatch between the model used in analytical derivation and that in simulation, the proposed adaptive driving strategy suppresses disturbances in a wide range of situations.","Automated vehicles; Car following; Cooperative driving; Heterogeneous platoon; Mixed traffic; String stability; Vehicle-infrastructure communication","en","journal article","","","","","","","","2020-04-21","","","Transport and Planning","","",""
"uuid:bfcfda6d-c591-4f25-9cef-b8f5d174610f","http://resolver.tudelft.nl/uuid:bfcfda6d-c591-4f25-9cef-b8f5d174610f","Calibration and validation of cellular automaton traffic flow model with empirical and experimental data","Jin, C.J. (TU Delft Transport and Planning; Southeast University; Jiangsu Province Collaborative Innovation Center of Modern Urban Traffic Technologies); Knoop, V.L. (TU Delft Transport and Planning); Jiang, Rui (MOE Key Laboratory for Urban Transportation Complex Systems Theory and Technology); Wang, Wei (Southeast University; Jiangsu Province Collaborative Innovation Center of Modern Urban Traffic Technologies); Wang, Hao (Southeast University; Jiangsu Province Collaborative Innovation Center of Modern Urban Traffic Technologies)","","2018","For traffic flow models, calibration and validation are essential. Cellular automaton (CA) models are a special class of models, describing the movement of vehicles in discretised space and time. However, the previous work on calibration and validation does not discuss CA models systematically. This study calibrates and validates a stochastic CA model. The authors use a simple CA model, which only has two important parameters to be calibrated. The methodology for optimisation is to minimise the relative root mean square error between two properties: The averaged velocity and the variation of velocities in a platoon at a given density. Three different sites are used as cases to show the methodology, for which different types of data (video trajectories or GPS data) are available. The authors find that the best model parameters vary for the different locations. This may result from various driving strategies and potential tendencies. Thus, it is concluded that for CA models, various traffic flow phenomena need to be simulated by various parameters.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-08-14","","","Transport and Planning","","",""
"uuid:5022ef7a-bb3e-44fe-b114-1c0eed25e855","http://resolver.tudelft.nl/uuid:5022ef7a-bb3e-44fe-b114-1c0eed25e855","Validating a workflow for tree inventory updating with 3d point clouds obtained by mobile laser scanning","Wang, J. (TU Delft Optical and Laser Remote Sensing; Fugro); Lindenbergh, R.C. (TU Delft Optical and Laser Remote Sensing)","","2018","Urban trees are an important component of our environment and ecosystem. Trees are able to combat climate change, clean the air and cool the streets and city. Tree inventory and monitoring are of great interest for biomass estimation and change monitoring. Conventionally, parameters of trees are manually measured and documented in situ, which is not efficient regarding labour and costs. Light Detection And Ranging (LiDAR) has become a well-established surveying technique for the acquisition of geo-spatial information. Combined with automatic point cloud processing techniques, this in principle enables the efficient extraction of geometric tree parameters. In recent years, studies have investigated to what extend it is possible to perform tree inventories using laser scanning point clouds. Give the availability of a city of Delft Open data tree repository, we are now able to present, validate and extend a workflow to automatically obtain tree data from tree location until tree species. The results of a test over 47 trees show that the proposed methods in the workflow are able to individual urban trees. The tree species classification results based on the extracted tree parameters show that only one tree was wrongly classified using k-means clustering.","Mobile laser scanning; Point cloud data; Tree classification; Tree inventory","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:b3e3a462-45b4-4430-8137-0653012e5399","http://resolver.tudelft.nl/uuid:b3e3a462-45b4-4430-8137-0653012e5399","Synthesis and characterization of argyrodite solid electrolytes for all-solid-state Li-ion batteries","Zhang, Zhixia (Yanshan University); Zhang, Long (Yanshan University); Liu, Yanyan (Yanshan University); Yu, C. (TU Delft RST/Fundamental Aspects of Materials and Energy); Yan, Xinlin (Technische Universität Wien); Xu, Bo (Yanshan University); Wang, L. (Yanshan University)","","2018","Li6PS5X (X = Cl, Br, I) argyrodites possess high ionic conductivity but with rather scattered values due to various processing conditions. In this work, Li6PS5X solid electrolytes were prepared by solid-state sintering or mechanical alloying and optimized with or without excess Li2S. Solid-state sintering prefers excess Li2S, whereas mechanical alloying prefers stoichiometric Li2S to synthesize high-purity samples with high ionic conductivity. Solid-state sintering is also more suitable than mechanical milling for high ionic conductivity. Li6PS5Cl with the highest ionic conductivity among Li6PS5X was comprehensively characterized for electrochemical performance and air stability. MoS2/Li6PS5Cl all-solid-state batteries assembled with Li6PS5Cl-coated MoS2 as cathode and with Li6PS5Cl as solid electrolyte demonstrate high capacity and good cycling stability.","All-solid-state batteries; Argyrodites; LiPSCl; Solid electrolytes; Sulfides","en","journal article","","","","","","Accepted Author Manuscript","","2020-03-08","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:1ed16811-3dc1-4eaa-adf5-3b87375dd2c7","http://resolver.tudelft.nl/uuid:1ed16811-3dc1-4eaa-adf5-3b87375dd2c7","Rainfall-induced slope collapse with coupled material point method","Wang, B. (TU Delft Geo-engineering; Chinese Academy of Sciences); Vardon, P.J. (TU Delft Geo-engineering); Hicks, M.A. (TU Delft Geoscience and Engineering; TU Delft Geo-engineering)","","2018","Rainfall-induced slope failures are a major category of slope failure, with incidents likely to increase with the predicted escalation of extreme rainfall events. Traditional numerical methods such as the finite element method are often restricted in their applicability to small deformation analyses. Therefore, incomplete descriptions of the failure mechanism and failure consequence may be obtained, due to the evolving deformations and progressive failure being ignored. A one-point, two-phase material point method (MPM) formulation is proposed to consider the influence of rainfall on slope failure. Due to the characteristics of MPM in capturing the large deformations, the complete failure process, from initiation to failure, of a slope subjected to rainfall infiltration is presented. The soil behaviour is described by a Mohr–Coulomb strain-softening model based on Bishop's effective stress. The two-phase analysis shows that the rainfall-affected slope is initially stable, until the soil shear strength reduces due to the reduction of suction in the slope starting from the surface, leading to a superficial failure mode, which in turn leads to a complete slope failure. Friction angle and residual cohesion are shown to play important roles in the development of the slope failure.","Large deformations; Material point method; Rainfall-induced failure; Slope stability; Unsaturated soils","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-10-01","","Geoscience and Engineering","Geo-engineering","","",""
"uuid:d36194de-1203-4342-bf20-8d03380c5b40","http://resolver.tudelft.nl/uuid:d36194de-1203-4342-bf20-8d03380c5b40","Managed aquifer recharge as a barrier for ozone-based advanced oxidation by-products: BrO3- and H2O2","Wang, F. (TU Delft Sanitary Engineering)","van der Hoek, J.P. (promotor); van Halem, D. (promotor); Delft University of Technology (degree granting institution)","2018","Managed Aquifer Recharge (MAR) is a technology that relies on soil passage - after pond infiltration - for water treatment. MAR is a proven technology for the removal of pathogenic micro-organisms, turbidity and a selection of specific organic micro-pollutions (OMPs). Nevertheless, removal of the wide variety of OMPs found in surface waters requires additional treatment. The application of O3-based advanced oxidation processes (AOPs) before MAR has been proposed as a smart solution, because previous studies have documented complementary and synergetic benefits for the removal of OMPs. However, the effect of the installation of O3-based AOP as a chemical process on the subsequent MAR as a biological process is not known yet. Especially the behaviour and fate of O3-based AOP by-products and residuals on MAR raise many questions. This thesis focused on the behaviour and fate of BrO3 - as an O3-based AOP by-product and
H2O2 as an AOP residual during MAR.","Managed aquifer recharge; Advanced oxidation processes; Bromate; Hydrogen peroxide; By-product; Iron; Denitrifying bacteria","en","doctoral thesis","","978-90-6562-422-2","","","","","","","","","Sanitary Engineering","","",""
"uuid:edbcde5f-0ec6-4683-9fcd-891500d198a8","http://resolver.tudelft.nl/uuid:edbcde5f-0ec6-4683-9fcd-891500d198a8","Metal-Organic-Framework-Mediated Nitrogen-Doped Carbon for CO2 Electrochemical Reduction","Wang, R. (TU Delft ChemE/Catalysis Engineering); Sun, X. (TU Delft ChemE/Catalysis Engineering); Ould-Chikh, Samy (King Abdullah University of Science and Technology); Osadchii, D. (TU Delft ChemE/Catalysis Engineering); Bai, F. (TU Delft ChemE/Catalysis Engineering; TU Delft Applied Sciences); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering); Gascon, Jorge (TU Delft ChemE/Catalysis Engineering; King Abdullah University of Science and Technology)","","2018","A nitrogen-doped carbon was synthesized through the pyrolysis of the well-known metal-organic framework ZIF-8, followed by a subsequent acid treatment, and has been applied as a catalyst in the electrochemical reduction of carbon dioxide. The resulting electrode shows Faradaic efficiencies to carbon monoxide as high as ∼78%, with hydrogen being the only byproduct. The pyrolysis temperature determines the amount and the accessibility of N species in the carbon electrode, in which pyridinic-N and quaternary-N species play key roles in the selective formation of carbon monoxide.","CO electrochemical reduction; electrocatalyst; MOF-mediated synthesis; nitrogen-doped carbon; ZIF-8","en","journal article","","","","","","Accepted Author Manuscript","","2019-05-18","Applied Sciences","","ChemE/Catalysis Engineering","","",""
"uuid:21c0153d-98a7-4132-8e27-ee0632180beb","http://resolver.tudelft.nl/uuid:21c0153d-98a7-4132-8e27-ee0632180beb","Comparative performance of different scale-down simulators of substrate gradients in Penicillium chrysogenum cultures: the need of a biological systems response analysis","Wang, G. (East China University of Science and Technology); Zhao, Junfei (East China University of Science and Technology); Haringa, C. (TU Delft ChemE/Transport Phenomena); Tang, W. (East China University of Science and Technology); Xia, Jianye (East China University of Science and Technology); Chu, Ju (East China University of Science and Technology); Zhuang, Yingping (East China University of Science and Technology); Zhang, Siliang (East China University of Science and Technology); Deshmukh, A.T. (DSM); van Gulik, W.M. (TU Delft OLD BT/Cell Systems Engineering); Heijnen, J.J. (TU Delft OLD BT/Cell Systems Engineering); Noorman, H.J. (TU Delft BT/Bioprocess Engineering; DSM)","","2018","In a 54 m3 large-scale penicillin fermentor, the cells experience substrate gradient cycles at the timescales of global mixing time about 20–40 s. Here, we used an intermittent feeding regime (IFR) and a two-compartment reactor (TCR) to mimic these substrate gradients at laboratory-scale continuous cultures. The IFR was applied to simulate substrate dynamics experienced by the cells at full scale at timescales of tens of seconds to minutes (30 s, 3 min and 6 min), while the TCR was designed to simulate substrate gradients at an applied mean residence time ((Formula presented.)) of 6 min. A biological systems analysis of the response of an industrial high-yielding P. chrysogenum strain has been performed in these continuous cultures. Compared to an undisturbed continuous feeding regime in a single reactor, the penicillin productivity (qPenG) was reduced in all scale-down simulators. The dynamic metabolomics data indicated that in the IFRs, the cells accumulated high levels of the central metabolites during the feast phase to actively cope with external substrate deprivation during the famine phase. In contrast, in the TCR system, the storage pool (e.g. mannitol and arabitol) constituted a large contribution of carbon supply in the non-feed compartment. Further, transcript analysis revealed that all scale-down simulators gave different expression levels of the glucose/hexose transporter genes and the penicillin gene clusters. The results showed that qPenG did not correlate well with exposure to the substrate regimes (excess, limitation and starvation), but there was a clear inverse relation between qPenG and the intracellular glucose level.","","en","journal article","","","","","","","","","","","ChemE/Transport Phenomena","","",""
"uuid:b3195587-b4da-4ef4-b706-84b9c63a1f4d","http://resolver.tudelft.nl/uuid:b3195587-b4da-4ef4-b706-84b9c63a1f4d","Satellite-clock modeling in single-frequency PPP-RTK processing","Wang, Kan (Curtin University); Khodabandeh, Amir (Curtin University); Teunissen, P.J.G. (TU Delft Mathematical Geodesy and Positioning; Curtin University); Nadarajah, Nandakumaran (Curtin University)","","2018","The real-time kinematic precise point positioning (PPP-RTK) technique enables integer ambiguity resolution by providing singlereceiver users with information on the satellite phase biases next to the standard PPP corrections. Using undifferenced and uncombined observations, rank deficiencies existing in the design matrix need to be eliminated to formestimable parameters. In this contribution, the estimability of the parameters was studied in single-frequency ionosphere-weighted scenario, given a dynamic satellite-clock model in the network Kalman filter. In case of latency of the network corrections, the estimable satellite clocks, satellite phase biases, and ionospheric delays need to be predicted over short time spans. With and without satellite-clock models incorporated in the network Kalman filter, different approaches were used to predict the network corrections. This contribution shows how the predicted network corrections responded to the presence and absence of satellite-clock models. These differences in the predicted network corrections were also reflected in the user positioning results. Using three different 1-Hz global positioning system (GPS) single-frequency data sets, two user stations in one small-scale network were used to compute the positioning results, applying predicted network corrections. The latency of the network products ranges from 3 to 10 s. It was observed that applying strong satellite-clock constraints in the network Kalman filter (i.e., with the process noise of 1 or 0.5mm per square root of second) reduced the root-mean squares (RMS) of the user positioning results to centimeters in the horizontal directions and decimeters in the vertical direction for latencies larger than 6 s, compared to the cases without a satellite-clock model.","Prediction; Real-time kinematic precise point positioning (PPP-RTK); Satellite-clock modeling; Single-frequency","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-09-12","","","Mathematical Geodesy and Positioning","","",""
"uuid:6ee0ecb4-336c-4ab3-9e5c-185d6cf0c94d","http://resolver.tudelft.nl/uuid:6ee0ecb4-336c-4ab3-9e5c-185d6cf0c94d","Understanding travellers’ preferences for different types of trip destination based on mobile internet usage data","Wang, Y. (TU Delft Transport and Planning); Correia, Gonçalo (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning); Timmermans, H. J.P.(Harry) (Eindhoven University of Technology; Nanjing University of Aeronautics and Astronautics)","","2018","New mobility data sources like mobile phone traces have been shown to reveal individuals’ movements in space and time. However, socioeconomic attributes of travellers are missing in those data. Consequently, it is not possible to partition the population and have an in-depth understanding of the socio-demographic factors influencing travel behaviour. Aiming at filling this gap, we use mobile internet usage behaviour, including one's preferred type of website and application (app) visited through mobile internet as well as the level of usage frequency, as a distinguishing element between different population segments. We compare the travel behaviour of each segment in terms of the preference for types of trip destinations. The point of interest (POI) data are used to cluster grid cells of a city according to the main function of a grid cell, serving as a reference to determine the type of trip destination. The method is tested for the city of Shanghai, China, by using a special mobile phone dataset that includes not only the spatial-temporal traces but also the mobile internet usage behaviour of the same users. We identify statistically significant relationships between a traveller's favourite category of mobile internet content and more frequent types of trip destinations that he/she visits. For example, compared to others, people whose favourite type of app/website is in the “tourism” category significantly preferred to visit touristy areas. Moreover, users with different levels of internet usage intensity show different preferences for types of destinations as well. We found that people who used mobile internet more intensively were more likely to visit more commercial areas, and people who used it less preferred to have activities in predominantly residential areas.","Data fusion; Mobile internet usage; Mobile phone data; Mobility analysis; Travel behaviour","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-09-23","","","Transport and Planning","","",""
"uuid:f7b3666c-67e4-4aeb-b33c-d67cb4f3c582","http://resolver.tudelft.nl/uuid:f7b3666c-67e4-4aeb-b33c-d67cb4f3c582","The Ozone Monitoring Instrument: Overview of 14 years in space","Levelt, Pieternel Felicitas (TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI)); Joiner, Joanna (NASA Goddard Space Flight Center); Tamminen, Johanna (Finnish Meteorological Institute (FMI)); Veefkind, j. Pepijn (TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI)); Bhartia, Pawan K. (NASA Goddard Space Flight Center); Zweers, Deborah C.Stein (Royal Netherlands Meteorological Institute (KNMI)); Duncan, Bryan N. (NASA Goddard Space Flight Center); Streets, David G. (Argonne National Laboratory); Eskes, Henk (Royal Netherlands Meteorological Institute (KNMI)); Van Der, Ronald A. (Royal Netherlands Meteorological Institute (KNMI)); McLinden, Chris (Environment Canada); Fioletov, Vitali (Environment Canada); Carn, Simon (Michigan Technological University); De Laat, Jos (Royal Netherlands Meteorological Institute (KNMI)); Deland, Matthew (Science Systems and Applications Inc.); Marchenko, Sergey (Science Systems and Applications Inc.); McPeters, Richard (NASA Goddard Space Flight Center); Ziemke, Jerald (NASA Goddard Space Flight Center; Morgan State University); Fu, Dejian (California Institute of Technology); Liu, Xiong (Harvard-Smithsonian Center for Astrophysics); Pickering, Kenneth (NASA Goddard Space Flight Center; University of Maryland); Apituley, Arnoud (Royal Netherlands Meteorological Institute (KNMI)); Abad, Gonzalo González (Harvard-Smithsonian Center for Astrophysics); Arola, Antti (Finnish Meteorological Institute (FMI)); Boersma, Folkert (Royal Netherlands Meteorological Institute (KNMI); Wageningen University & Research); Miller, Christopher Chan (Harvard-Smithsonian Center for Astrophysics); Chance, Kelly (Harvard-Smithsonian Center for Astrophysics); de Graaf, M. (Royal Netherlands Meteorological Institute (KNMI)); Hakkarainen, Janne (Finnish Meteorological Institute (FMI)); Hassinen, Seppo (Finnish Meteorological Institute (FMI)); Ialongo, Iolanda (Finnish Meteorological Institute (FMI)); Kleipool, Quintus (Royal Netherlands Meteorological Institute (KNMI)); Krotkov, Nickolay (NASA Goddard Space Flight Center); Li, Can (University of Maryland); Lamsal, Lok (Universities Space Research Association); Newman, Paul (NASA Goddard Space Flight Center); Nowlan, Caroline (Harvard-Smithsonian Center for Astrophysics); Suleiman, Raid (Harvard-Smithsonian Center for Astrophysics); Tilstra, Lieuwe Gijsbert (Royal Netherlands Meteorological Institute (KNMI)); Torres, Omar (NASA Goddard Space Flight Center); Wang, Huiqun (Harvard-Smithsonian Center for Astrophysics); Wargan, Krzysztof (NASA Goddard Space Flight Center; Science Systems and Applications Inc.)","","2018","This overview paper highlights the successes of the Ozone Monitoring Instrument (OMI) on board the Aura satellite spanning a period of nearly 14 years. Data from OMI has been used in a wide range of applications and research resulting in many new findings. Due to its unprecedented spatial resolution, in combination with daily global coverage, OMI plays a unique role in measuring trace gases important for the ozone layer, air quality, and climate change. With the operational very fast delivery (VFD; direct readout) and near real-time (NRT) availability of the data, OMI also plays an important role in the development of operational services in the atmospheric chemistry domain.","","en","review","","","","","","","","","","","Atmospheric Remote Sensing","","",""
"uuid:35205c17-6607-4674-8739-aeecfe5d7a48","http://resolver.tudelft.nl/uuid:35205c17-6607-4674-8739-aeecfe5d7a48","Discretionary lane-changing behavior: empirical validation for one realistic rule-based model","Jin, C.J. (TU Delft Transport and Planning; Southeast University); Knoop, V.L. (TU Delft Transport and Planning); Li, Dawei (Southeast University); Meng, Ling Yu (Southeast University); Wang, Hao (Southeast University)","","2018","In this paper, we discuss the mechanisms for discretionary lane-changing behavior in traffic flow. NGSIM video data are used to check the validity of different lane-changing rules, and 373 lane changes at 4 locations in US-101 highway are analyzed. We find that the classical lane-changing rules of rule-based model cannot explain many cases in the empirical dataset. Therefore, we propose one new decision rule, comparing the position after a time horizon of several seconds without a lane-change. This rule can be described as “to have a further position within 9 seconds”. The tests on NGSIM data show that this rule can explain most (76%) of the lane-changing cases. Besides, some data when lane changes do not occur are also studied. We find that most (81%) of non-lane-changing vehicles do not fulfill the new rule. Thus, it can be considered as one sufficient and necessary condition for discretionary lane-changing.","Discretionary lane change; lane-changing model; NGSIM data; non-lane-changing vehicles; rule-based model","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-10-23","","","Transport and Planning","","",""
"uuid:396839e6-4811-41de-8bbe-e22309e92a81","http://resolver.tudelft.nl/uuid:396839e6-4811-41de-8bbe-e22309e92a81","A Partition-Enabled Multi-Mode Band Approach to Arterial Traffic Signal Optimization","Ma, Wanjing (Tongji University); Zou, Li (Tongji University); An, Kun (Monash University); Gartner, Nathan H. (University of Massachusetts Lowell); Wang, M. (TU Delft Transport and Planning)","","2018","Arterial traffic signal coordination makes traffic flow more efficient and safer. This paper presents a partition-enabled multi-mode band (PM-BAND) model that is designed to solve the signal coordination problem for arterials with multiple modes, i.e., passenger cars and transit vehicles. The proposed method permits the progression bands to be broken if necessary and optimizes system partition and signal coordination in one unified framework. The impacts of traffic demand of passenger cars and transit vehicles as well as the geometry characteristics of the arterials are taken into account. Signal timings and waiting time of transit vehicles at stations are optimized simultaneously. The PM-BAND model is formulated as a mixed-integer linear program, which can be solved by the standard branch-and-bound technique. Numerical example results have demonstrated that the PM-BAND model can significantly reduce the average number of stops and delay compared with the other models, i.e., MAXBAND and MULTIBAND. Moreover, the progression bands generated by the PM-BAND model have a higher reliability and effectiveness.","Arterial signal coordination; Arteries; Automobiles; Bandwidth; Delays; Numerical models; Optimization; progression band; system partition; transit vehicles","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:1a8b777d-d66b-4193-9d46-24cb33dc47f4","http://resolver.tudelft.nl/uuid:1a8b777d-d66b-4193-9d46-24cb33dc47f4","A Robust Longitudinal Control Strategy of Platoons under Model Uncertainties and Time Delays","Chen, N. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); Alkim, Tom (Ministry of Infrastructure and the Environment); van Arem, B. (TU Delft Transport and Planning)","","2018","Automated vehicles are designed to free drivers from driving tasks and are expected to improve traffic safety and efficiency when connected via vehicle-to-vehicle communication, that is, connected automated vehicles (CAVs). The time delays and model uncertainties in vehicle control systems pose challenges for automated driving in real world. Ignoring them may render the performance of cooperative driving systems unsatisfactory or even unstable. This paper aims to design a robust and flexible platooning control strategy for CAVs. A centralized control method is presented, where the leader of a CAV platoon collects information from followers, computes the desired accelerations of all controlled vehicles, and broadcasts the desired accelerations to followers. The robust platooning is formulated as a Min-Max Model Predictive Control (MM-MPC) problem, where optimal accelerations are generated to minimize the cost function under the worst case, where the worst case is taken over the possible models. The proposed method is flexible in such a way that it can be applied to both homogeneous platoon and heterogeneous platoon with mixed human-driven and automated controlled vehicles. A third-order linear vehicle model with fixed feedback delay and stochastic actuator lag is used to predict the platoon behavior. Actuator lag is assumed to vary randomly with unknown distributions but a known upper bound. The controller regulates platoon accelerations over a time horizon to minimize a cost function representing driving safety, efficiency, and ride comfort, subject to speed limits, plausible acceleration range, and minimal net spacing. The designed strategy is tested by simulating homogeneous and heterogeneous platoons in a number of typical and extreme scenarios to assess the system stability and performance. The test results demonstrate that the designed control strategy for CAV can ensure the robustness of stability and performance against model uncertainties and feedback delay and outperforms the deterministic MPC based platooning control.","OA-Fund TU Delft","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:a2dacf4c-c10f-4800-81ca-5cf7e55be736","http://resolver.tudelft.nl/uuid:a2dacf4c-c10f-4800-81ca-5cf7e55be736","Forward-Looking Ultra-Wideband Synthetic Array Imaging","Wang, J. (TU Delft Microwave Sensing, Signals & Systems)","Yarovoy, Alexander (promotor); Delft University of Technology (degree granting institution)","2018","The expansion of microwave imaging applications in various fields proposes increasingly higher requirements (including spatial resolution, dynamic range, and signal-to-noise ratio) for microwave imaging systems. To achieve high-quality imaging, microwave imaging systems generally exploit spatial-, frequency- and polarization-diversities to probe objects of interest for information extraction. In practice, they are implemented by using array-, wideband/Ultra-wideband (UWB)-and polarimetry-techniques. So properly exploring these techniques is of great importance to design an advanced microwave imaging system. A motivation for the research presented in the thesis is to develop a ground penetrating radar (GPR) system to predict hazards ahead of tunnel boring machines (TBM) during tunnel excavation. In this circumstance, GPR antennas are mounted on the cutter-head of a TBM. With the rotation of the TBM cutter-head, GPR antennas collect electromagnetic (EM) signals over a synthetic circular aperture, which leads to the Radial-scanned Synthetic Aperture Radar (RadSAR). The rotation of the antenna array benefits the formation of the RadSAR but makes it distinct from traditional SAR modalities as well.","microwave imaging; Synthetic Aperture Radar; Full Polarimetry; Rotated antenna array; signal fusion; array design; Ultra-wide band (UWB); Ground penetrating radar","en","doctoral thesis","","978-94-028-1007-3","","","","","","","","","Microwave Sensing, Signals & Systems","","",""
"uuid:f4e3eb5b-6c8b-43a8-8b9d-80d213984aa8","http://resolver.tudelft.nl/uuid:f4e3eb5b-6c8b-43a8-8b9d-80d213984aa8","Quantized Majorana conductance","Zhang, H. (TU Delft QRD/Kouwenhoven Lab); Liu, Chun Xiao (University of Maryland); Gazibegovic, S. (TU Delft QRD/Kouwenhoven Lab; Eindhoven University of Technology); Xu, D. (TU Delft QRD/Kouwenhoven Lab); Logan, John A. (University of California); Wang, Guanzhong (TU Delft QRD/Kouwenhoven Lab); van Loo, N. (TU Delft Applied Sciences); Bommer, J.D.S. (TU Delft QRD/Kouwenhoven Lab); de Moor, M.W.A. (TU Delft QRD/Kouwenhoven Lab); Car, D. (TU Delft QRD/Kouwenhoven Lab; Eindhoven University of Technology); op het Veld, R.L.M. (TU Delft QRD/Kouwenhoven Lab; Eindhoven University of Technology); Van Veldhoven, Petrus J. (Eindhoven University of Technology); Kölling, S. (TU Delft QRD/Kouwenhoven Lab; Eindhoven University of Technology); Verheijen, M.P.A.M. (TU Delft Integral Design & Management; Eindhoven University of Technology; Philips Research); Pendharkar, Mihir (University of California); Pennachio, Daniel J. (University of California); Shojaei, Borzoyeh (University of California); Lee, Joon Sue (University of California); Palmstrøm, Chris J. (University of California); Bakkers, E.P.A.M. (TU Delft QN/Bakkers Lab; Eindhoven University of Technology); Sarma, S. Das (University of Maryland); Kouwenhoven, Leo P. (TU Delft QRD/Kouwenhoven Lab; Microsoft Quantum Lab Delft)","","2018","Majorana zero-modes - a type of localized quasiparticle - hold great promise for topological quantum computing. Tunnelling spectroscopy in electrical transport is the primary tool for identifying the presence of Majorana zero-modes, for instance as a zero-bias peak in differential conductance. The height of the Majorana zero-bias peak is predicted to be quantized at the universal conductance value of 2e 2 /h at zero temperature (where e is the charge of an electron and h is the Planck constant), as a direct consequence of the famous Majorana symmetry in which a particle is its own antiparticle. The Majorana symmetry protects the quantization against disorder, interactions and variations in the tunnel coupling. Previous experiments, however, have mostly shown zero-bias peaks much smaller than 2e 2 /h, with a recent observation of a peak height close to 2e 2 /h. Here we report a quantized conductance plateau at 2e 2 /h in the zero-bias conductance measured in indium antimonide semiconductor nanowires covered with an aluminium superconducting shell. The height of our zero-bias peak remains constant despite changing parameters such as the magnetic field and tunnel coupling, indicating that it is a quantized conductance plateau. We distinguish this quantized Majorana peak from possible non-Majorana origins by investigating its robustness to electric and magnetic fields as well as its temperature dependence. The observation of a quantized conductance plateau strongly supports the existence of Majorana zero-modes in the system, consequently paving the way for future braiding experiments that could lead to topological quantum computing.","Electronic properties and materials; Nanowires; Superconducting properties and materials","en","journal article","","","","","","Accepted Author Manuscript This title has a addendum: editorial expression of concern, see Relations below","","2018-09-28","Applied Sciences","","QRD/Kouwenhoven Lab","","",""
"uuid:91bae1df-939e-4b7c-ad6f-310977978baf","http://resolver.tudelft.nl/uuid:91bae1df-939e-4b7c-ad6f-310977978baf","Multi-GNSS PPP-RTK: From large- to Small-Scale networks","Nadarajah, Nandakumaran (Curtin University); Khodabandeh, Amir (Curtin University); Wang, Kan (Curtin University); Choudhury, Mazher (Curtin University); Teunissen, P.J.G. (TU Delft Mathematical Geodesy and Positioning; Curtin University)","","2018","Precise point positioning (PPP) and its integer ambiguity resolution-enabled variant, PPP-RTK (real-time kinematic), can benefit enormously from the integration of multiple global navigation satellite systems (GNSS). In such a multi-GNSS landscape, the positioning convergence time is expected to be reduced considerably as compared to the one obtained by a single-GNSS setup. It is therefore the goal of the present contribution to provide numerical insights into the role taken by the multi-GNSS integration in delivering fast and high-precision positioning solutions (sub-decimeter and centimeter levels) using PPP-RTK. To that end, we employ the Curtin PPP-RTK platform and process data-sets of GPS, BeiDou Navigation Satellite System (BDS) and Galileo in stand-alone and combined forms. The data-sets are collected by various receiver types, ranging from high-end multi-frequency geodetic receivers to low-cost single-frequency mass-market receivers. The corresponding stations form a large-scale (Australia-wide) network as well as a small-scale network with inter-station distances less than 30 km. In case of the Australia-wide GPS-only ambiguity-float setup, 90% of the horizontal positioning errors (kinematic mode) are shown to become less than five centimeters after 103 min. The stated required time is reduced to 66 min for the corresponding GPS + BDS + Galieo setup. The time is further reduced to 15 min by applying single-receiver ambiguity resolution. The outcomes are supported by the positioning results of the small-scale network.","Carrier phase ambiguity resolution; Global Navigation Satellite Systems (GNSS); Ionosphere weighted model; Network in-loop; PPP-RTK network and user","en","journal article","","","","","","","","","","","Mathematical Geodesy and Positioning","","",""
"uuid:b867135c-0df5-439a-a0f7-702d4f67a593","http://resolver.tudelft.nl/uuid:b867135c-0df5-439a-a0f7-702d4f67a593","On the stability relations between tidal asymmetry and morphologies of tidal basins and estuaries","Zhou, Zeng; Coco, Giovanni (The University of Auckland); Townend, Ian (University of Southampton); Gong, Zheng; Wang, Zhengbing (TU Delft Coastal Engineering); Zhang, Changkuan","","2018","Simple stability relationships are practically useful to provide a rapid assessment of coastal and estuarine landforms in response to human interventions and long‐term climate change. In this contribution, we review a variety of simple stability relationships which are based on the analysis of tidal asymmetry (shortened to “TA”). Most of the existing TA‐based stability relationships are derived using the one‐dimensional tidal flow equations assuming a certain regular shape of the tidal channel cross‐sections. To facilitate analytical solutions, specific assumptions inevitably need to be made e.g. by linearising the friction term and dropping some negligible terms in the tidal flow equations. We find that three major types of TA‐based stability relationships have been proposed between three non‐dimensional channel geometric ratios (represented by the ratio of channel widths, ratio of wet surface areas and ratio of storage volumes) and the tide‐related parameter a/h (i.e. the ratio between tidal amplitude and mean water depth). Based on established geometric relations, we use these non‐dimensional ratios to re‐state the existing relationships so that they are directly comparable. Available datasets are further extended to examine theutility of these TA‐based relationships. Although a certain agreement is shown for these relationships, we also observe a large scatter of data points which are collected in different types of landscape, hydrodynamic and sedimentologic settings over the world. We discuss in detail the potential reasons for this large scatter and subsequently elaborate on the limited applicability of the various TA‐based stability relationships for practical use. We highlight the need to delve further into what constitutes equilibrium and what is needed to develop more robust measures to determine the morphological state of these systems.","tidal basins; estuarine morphologies; tidal asymmetry; stability relationships","en","journal article","","","","","","","","2019-04-01","","","Coastal Engineering","","",""
"uuid:a4ac58a3-eba4-4013-b8ab-b7db09d84ce0","http://resolver.tudelft.nl/uuid:a4ac58a3-eba4-4013-b8ab-b7db09d84ce0","Bromate reduction by iron(II) during managed aquifer recharge: A laboratory-scale study","Wang, F. (TU Delft Sanitary Engineering); Salgado Ismodes, V.A.; van der Hoek, J.P. (TU Delft Sanitary Engineering; Strategic Centre); van Halem, D. (TU Delft Sanitary Engineering)","","2018","The removal of bromate (BrO3 -) as a byproduct of ozonation in subsequent managed aquifer recharge (MAR) systems has so far gained little attention. This preliminary study with anoxic batch experiments was executed to explore the feasibility of chemical BrO3 - reduction in Fe-reducing zones of MAR systems and to estimate potential inhibition by NO3 -. Results show that the reaction rate was affected by initial Fe2+/BrO3 - ratios and by pH. The pH dropped significantly due to the hydrolysis of Fe3+ to hydrous ferric oxide (HFO) flocs. These HFO flocs were found to adsorb Fe2+, especially at high Fe2+/BrO3 - ratios, whereas at low Fe2+/BrO3 - ratios, the mass sum loss of BrO3 - and Br- indicated intermediate species formation. Under MAR conditions with relatively low BrO3 - and Fe2+ concentrations, BrO3 - can be reduced by naturally occurring Fe2+, as the extensive retention time in MAR systems will compensate for the slow reaction kinetics of low BrO3 - and Fe2+ concentrations. Under specific flow conditions, Fe2+ and NO3 - may co-occur during MAR, but NO3 - hardly competes with BrO3 -, since Fe2+ prefers BrO3 - over NO3 -. However, it was found that when NO3 - concentration exceeds BrO3 - concentration by multiple orders of magnitude, NO3 - may slightly inhibit BrO3 - reduction by Fe2+.","Bromate reduction; Drinking water treatment; Iron-reducing zones; Managed aquifer recharge; Nitrate; Ozonation; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:60512fac-bfc5-42ac-8cc5-872231043cc1","http://resolver.tudelft.nl/uuid:60512fac-bfc5-42ac-8cc5-872231043cc1","Effect of salt on the metabolism of 'Candidatus Accumulibacter' clade I and II","Wang, Zhongwei (King Abdullah University of Science and Technology); Dunne, Aislinn (King Abdullah University of Science and Technology); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology); Saikaly, Pascal E. (King Abdullah University of Science and Technology)","","2018","Saline wastewater is known to affect the performance of phosphate-accumulating organisms (PAOs) in enhanced biological phosphorus removal (EBPR) process. However, studies comparing the effect of salinity on different PAO clades are lacking. In this study, 'Candidatus Accumulibacter phosphatis' Clade I and II (hereafter referred to as PAOI and PAOII) were highly enriched (~90% in relative abundance as determined by quantitative FISH) in the form of granules in two sequencing batch reactors. Anaerobic and aerobic batch experiments were conducted to evaluate the effect of salinity on the kinetics and stoichiometry of PAOI and PAOII. PAOI and PAOII communities showed different priority in using polyphosphate (poly-P) and glycogen to generate ATP in the anaerobic phase when exposed to salt, with PAOI depending more on intracellular poly-P degradation (e.g., the proportion of calculated ATP derived from poly-P increased by 5-6% at 0.256 mol/L NaCl or KCl) while PAOII on glycolysis of intracellularly stored glycogen (e.g., the proportion of calculated ATP derived from glycogen increased by 29-30% at 0.256 mol/L NaCl or KCl). In the aerobic phase, the loss of phosphate uptake capability was more pronounced in PAOII due to the higher energy cost to synthesize their larger glycogen pool compared to PAOI. For both PAOI and PAOII, aerobic conversion rates were more sensitive to salt than anaerobic conversion rates. Potassium (K+) and sodium (Na+) ions exhibited different effect regardless of the enriched PAO culture, suggesting that the composition of salt is an important factor to consider when studying the effect of salt on EBPR performance.","'Candidatus Accumulibacter phosphatis' clade I and II; Enhanced biological phosphorus removal; Phosphate-accumulating organism (PAO); Saline wastewater; Water scarcity","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:58172132-5e18-471f-94c9-cc83c54c5f9d","http://resolver.tudelft.nl/uuid:58172132-5e18-471f-94c9-cc83c54c5f9d","Review of warm mix rubberized asphalt concrete: Towards a sustainable paving technology","Wang, H. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Apostolidis, P. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering)","","2018","In recent years, transportation agencies and the general public alike are demanding increased considerations of sustainability in transport infrastructure. Warm mix asphalt (WMA) is developed for reducing energy consumptions and emissions in asphalt paving industry. In addition, the use of rubberized asphalt concrete (RAC) has proven to be economically and environmentally sound and effective in improving the performance of pavements around the world. The combination of WMA and RAC, namely WarmRAC, is a novel and promising paving technology that can realize pavement sustainability from principles to practices. This study summarizes the best practices and recent research findings on warm mix rubberized asphalt concrete, including mix design, construction techniques, performance evaluation, feasibility of recycling, and environmental and economic benefits. Although most research findings to date about WarmRAC are positive, it still has a long way for WarmRAC to be fully adopted worldwide. Therefore, life cycle assessment including environmental and economic impacts, and long-term performance of WarmRAC need further research with involvement of transportation agencies, industry and academia.","Asphalt rubber; Construction; Mix design; Rubberized asphalt concrete; Sustainability; Warm mix asphalt","en","journal article","","","","","","","","2020-01-02","","","Pavement Engineering","","",""
"uuid:4f87a746-5088-4fc2-b711-15c50be2411b","http://resolver.tudelft.nl/uuid:4f87a746-5088-4fc2-b711-15c50be2411b","Shear capacity of a novel joint between corrugated steel web and concrete lower slab","Wang, Sihao (Tongji University); He, Jun (Changsha University of Science and Technology); Liu, Yuqing (Tongji University); Li, Chuanxi (Changsha University of Science and Technology); Xin, H. (TU Delft Steel & Composite Structures; Tongji University)","","2018","Composite girder with corrugated steel web is one of the promising concrete-steel hybrid structures with superior properties and cost effectiveness widely applied in highway and railway bridges. The connection between concrete slabs and corrugated steel web is an important part of such composite structure. In order to improve pouring quality and durability of concrete for joint structure between corrugated steel webs and concrete lower slab, the validity of placing lower slab on the inner side of corrugated steel webs was confirmed and a new joint structure with perforated plate connectors was proposed. Push-out tests on proposed joint structure with different parameters including the welding width and the plate thickness were carried out to study their shear strength, shear stiffness, failure modes and relative slip characteristics. Subsequently, three-dimensional finite element models taking material non-linearity and nonlinear contact between steel and concrete interface into consideration were built and validated by the push-out tests. Afterwards, parametric studies were performed to further investigate the influences of geometrical parameters (such as width, height and thickness of perforated steel plate) and material parameters including steel yielding strength and concrete compressive strength on ultimate shear strength and failure mode of the joint structure. Analytical results indicate that the shear loading capacity is increased with the thickness, the width and height of perforated plate, and the compressive strength of concrete. However, steel yielding strength, presence or absence of perforating rebar, have a negligible effect on ultimate shear strength of the joint structure. Finally, prediction equations of shear capacity were provided and compared with experimental and numerical results. The calculated shear capacity agrees well with experimental and numerical ones, indicating provided analytical equations can accurately predict shear capacity for such novel joint structure.","Composite girder; Corrugated steel web; Finite element analysis; Joint structure; Push-out tests; Shear capacity","en","journal article","","","","","","","","2020-02-29","","","Steel & Composite Structures","","",""
"uuid:fbaea3ac-1120-487b-87dc-87a93bd0b119","http://resolver.tudelft.nl/uuid:fbaea3ac-1120-487b-87dc-87a93bd0b119","Analytical solutions for crack opening displacements of eccentric cracks in thin-walled metallic plates","Wang, W. (TU Delft Structural Integrity & Composites); Rans, C.D. (TU Delft Structural Integrity & Composites); Benedictus, R. (TU Delft Structural Integrity & Composites)","","2018","In the context of the prevalence of thin-walled metallic aerospace structures, the added resistance to crack propagation offered by a built-up structure is desirable from a damage tolerance standpoint. The analysis of failure in such structures, however, is limited by the lack of crack opening solutions. This paper develops analytical models that calculate crack opening displacements (CODs) for a more general cracking scenario, i.e. non-symmetric cracks. The proposed models are based on the Westergaard stress functions. It is then found that the COD solution of one model is particularly accurate. The potential significance of the obtained solutions lies in analysing failure in built-up structures containing non-symmetric cracks. The crack opening solution is particularly useful in estimating the load transfer between cracked body and intact bridging structures in built-up structures using the principle of displacement compatibility.","Crack opening displacement; Eccentric crack; Load redistribution; Stress intensity factor; Westergaard stress distribution","en","journal article","","","","","","","","2019-12-01","","","Structural Integrity & Composites","","",""
"uuid:66a07f85-d096-4bf0-83e1-fc6ac8d7174b","http://resolver.tudelft.nl/uuid:66a07f85-d096-4bf0-83e1-fc6ac8d7174b","Modelling of the long-term behaviour of transition zones: Prediction of track settlement","Wang, Haoyu (TU Delft Railway Engineering); Markine, V.L. (TU Delft Railway Engineering)","","2018","Transition zones in railway tracks are the locations with considerable changes in the vertical support structures. Typically, they are located near engineering structures, such as bridges, culverts, tunnels and level crossings. In such locations, the variation of the vertical stiffness and the differential settlement of the track (when the foundation settles unevenly) result in amplification of the dynamic forces acting on the track. This amplification contributes to the degradation process of ballast and subgrade, ultimately resulting in the deterioration of vertical track geometry (settlement). To analyse and predict the accumulated settlement of the track in transition zones, a methodology using the iterative procedure is proposed. The methodology includes the finite element simulations of the vehicle-track and sleeper-ballast interaction during a train passing a transition zone; and iterative calculations of accumulated track settlement, based on an empirical model for ballast settlement. The simulations are performed using a 3-D dynamic finite element model (explicit integration) of a track transition zone, which accounts for the differential stiffness and the differential settlement of the track. Also, nonlinear contact elements between sleepers and ballast are used. As a result, the model can perform the detailed analysis of the stresses in ballast and accounts for the effects of vehicle dynamics. The model was validated against field measurements. The empirical settlement model describes the two-stage settlement of ballast and the nonlinear relationship between ballast stresses and permanent settlement. The proposed methodology is demonstrated by calculating the track settlement in the transition zone for 60,000 loading cycles (3.5 MGT). The dynamic responses such as ballast stresses are analysed to study the effect of the settlement. The parametric study of the iteration step used in the accumulated settlement procedure has been performed, based on which the optimal step is suggested.","Empirical settlement model; Railway track modelling; Settlement prediction; Transition zone","en","journal article","","","","","","","","2019-12-22","","","Railway Engineering","","",""
"uuid:d40ae2df-8c80-4cbc-a0b1-0a31ae1d6009","http://resolver.tudelft.nl/uuid:d40ae2df-8c80-4cbc-a0b1-0a31ae1d6009","Structural health monitoring of railway transition zones using satellite radar data","Wang, Haoyu (TU Delft Railway Engineering); Chang, L. (TU Delft Railway Engineering); Markine, V.L. (TU Delft Railway Engineering)","","2018","Transition zones in railway tracks are locationswith considerable changes in the rail-supporting structure. Typically, they are located near engineering structures, such as bridges, culverts and tunnels. In such locations, severe differential settlements often occur due to the different material properties and structure behavior. Without timely maintenance, the differential settlement may lead to the damage of track components and loss of passenger’s comfort. To ensure the safety of railway operations and reduce the maintenance costs, it is necessary to consecutively monitor the structural health condition of the transition zones in an economical manner and detect the changes at an early stage. However, using the current in situ monitoring of transition zones is hard to achieve this goal, because most in situ techniques (e.g., track-measuring coaches) are labor-consuming and usually not frequently performed (approximately twice a year in the Netherlands). To tackle the limitations of the in situ techniques, a Satellite Synthetic Aperture Radar (InSAR) system is presented in this paper, which provides a potential solution for a consecutive structural health monitoring of transition zones with bi-/tri-weekly data update and mm-level precision. To demonstrate the feasibility of the InSAR system for monitoring transition zones, a transition zone is tested. The results show that the differential settlement in the transition zone and the settlement rate can be observed and detected by the InSAR measurements. Moreover, the InSAR results are cross-validated against measurements obtained using a measuring coach and a Digital Image Correlation (DIC) device. The results of the three measuring techniques show a good correlation, which proves the applicability of InSAR for the structural health monitoring of transition zones in railway track.","Railway; Satellite InSAR; Settlement; Structural health inspection; Transition zones; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:4149ddc1-d80e-41fc-aec7-251024d35ab6","http://resolver.tudelft.nl/uuid:4149ddc1-d80e-41fc-aec7-251024d35ab6","Multistable mechanical metamaterials for 3D positioning","Zhang, Y. (TU Delft Computational Design and Mechanics); Wang, Q. (TU Delft Computational Design and Mechanics); Tichem, M. (TU Delft Micro and Nano Engineering); van Keulen, A. (TU Delft Computational Design and Mechanics)","","2018","","multistability; metamaterials; positioning","en","abstract","","","","","","","","","","","Computational Design and Mechanics","","",""
"uuid:a36435d7-35a0-4587-b142-a7e2f44ba606","http://resolver.tudelft.nl/uuid:a36435d7-35a0-4587-b142-a7e2f44ba606","High-Speed Flight of Quadrotor Despite Loss of Single Rotor","Sun, Sihao (Student TU Delft); Sijbers, Leon (Student TU Delft); Wang, Xuerui (TU Delft Control & Simulation); de Visser, C.C. (TU Delft Control & Simulation)","","2018","In order to achieve high-speed flight of a damaged quadrotor with complete loss of a single rotor, a multiloop hybrid nonlinear controller is designed. By fully making use of sensor measurements, the model dependence of this control method is reduced, which is conducive to handling disturbance from the unknown aerodynamic effects. This controller is tested on a quadrotor vehicle with one rotor completely removed in the high-speed condition. Free flights are performed in the Open Jet Facility, a large-scale wind tunnel. Over 9 m/s flight speed is reached for the damaged quadrotor in these tests. In addition, several high-speed spin-induced aerodynamic effects are discovered and analyzed.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-05","","","Control & Simulation","","",""
"uuid:6cddf1c4-24ce-45df-b6c7-cd461676eab7","http://resolver.tudelft.nl/uuid:6cddf1c4-24ce-45df-b6c7-cd461676eab7","Decoupled textures for broadband absorption enhancement beyond Lambertian light trapping limit in thin-film silicon-based solar cells","Vismara, R. (TU Delft Photovoltaic Materials and Devices); Dane Linssen, N. P. (Student TU Delft); Wang, Ken X. (Stanford University; Huazhong University of Science and Technology); Fan, Shanhui (Stanford University); Isabella, O. (TU Delft Photovoltaic Materials and Devices); Zeman, M. (TU Delft Electrical Sustainable Energy)","Freundlich, Alex (editor); Topic, Marko (editor); Yamada, Akira (editor)","2018","We present a modelling study of thin silicon based solar cells endowed with periodic and decoupled front/back textures. After careful optimization, the proposed device models exhibit absorption beyond the Lambertian light trapping limit for a wide range of light angles of incidence. The advanced light management scheme is applied to (nano)crystalline silicon solar cells, where the benefits of texturing the absorber rather than the supporting layers is clear and to barium (di)silicide solar cells, which could achieve an implied photocurrent densityof41.1 mA/cm2 for a thickness of only 2 \mum.","barium silicide; Lambertian scattering; light trapping; nano-crystalline silicon; periodic gratings; thin-film silicon","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","","","Electrical Sustainable Energy","Photovoltaic Materials and Devices","","",""
"uuid:176ddb86-5cc9-4ddd-87d0-aebee47b5b1e","http://resolver.tudelft.nl/uuid:176ddb86-5cc9-4ddd-87d0-aebee47b5b1e","Committee III.2: Fatigue and Fracture","Garbatov, Y.; Ås, S.K.; Branner, Kim; Choi, B.K.; den Besten, J.H. (TU Delft Ship Hydromechanics and Structures); Dong, P.; Lillemäe, I.; Lindstrom, P.; Lourenço de Souz, M.; Parmentier, G.; Quéméner, Y.; Rizzo, C.M.; Rörup, J.; Vhanmane, Suhas; Villavicencio, R.; Wang, F.; Yuan, Yue","Kaminski, M.L. (editor); Rigo, P. (editor)","2018","Concern for crack initiation and growth under cyclic loading as well as unstable crack propagation and tearing in the ship and offshore structures. Due attention shall be paid to the suitability and uncertainty of physical models and testing. Consideration is to be given to practical application, statistical description and fracture control methods in design, fabrication and service.","Fatigue; fracture; steel; aluminium; polymer composites; damage accumulation; crack growth; fabrication; inspection; maintenance; reliability; design; verification; fitness for service; rules; standards","en","conference paper","IOS Press","","","","","","","","","","Ship Hydromechanics and Structures","","",""
"uuid:2052f042-bae5-467d-bd35-f0999bdcda64","http://resolver.tudelft.nl/uuid:2052f042-bae5-467d-bd35-f0999bdcda64","Experimental Assessment of the Coarray Concept for DoA Estimation in Wireless Communications","Wang, Jiachen (Katholieke Universiteit Leuven); Xu, Hantao (Katholieke Universiteit Leuven); Leus, G.J.T. (TU Delft Signal Processing Systems); Vandenbosch, Guy A.E. (Katholieke Universiteit Leuven)","","2018","The direction of arrival (DoA) estimation performance of three different coarray structures, namely, the nested array, the coprime sampling array, and the sparse ruler array are presented and compared. The coarray concept makes it possible to detect the DoAs of much more sources than the number of physical antennas. Crucial is that for the first time, these coarrays are investigated based on real measurements conducted on a demonstrator platform. Based on the results obtained, the conclusion is clear. The MUSIC algorithm-based coarray concept with spatial smoothing is not suitable for DoA estimation in practical circumstances due to the unavoidable multipath phenomenon.","Coarray; Coprime Sampling Array; Data Measurements; Direction of Arrival (DoA) estimation; MUSIC; Nested Array; Sparse Ruler Array; Spatial Smoothing","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-12-31","","","Signal Processing Systems","","",""
"uuid:b31008b0-7fdc-41fe-a717-42998c3de700","http://resolver.tudelft.nl/uuid:b31008b0-7fdc-41fe-a717-42998c3de700","Efficient C2-weighting for image warping","Xian, Chuhua (South China University of Technology); Jin, Shuo (The Chinese University of Hong Kong); Wang, C.C. (TU Delft Materials and Manufacturing)","","2018","Handle-driven image warping based on linear blending is widely used in many applications because of its merits on intuitiveness, efficiency, and ease of implementation. In this paper, we develop a method to compute high-quality weights within a closed domain for image warping. The property of C2 continuity in weights is guaranteed by the carefully formulated basis functions. The efficiency of our algorithm is ensured by a closed-form formulation of the computation for weights. The cost of inserting a new handle is only the time to evaluate the distances from the new handle to all other sample points in the domain. A virtual handle insertion algorithm is developed to allow users to freely place handles within the domain while preserving the satisfaction of all expected criteria on weights for linear blending. Experimental examples for real-time applications are shown to demonstrate the effectiveness of this method.","applications; computer graphics; hardware; image warping; integrated circuits; memory technologies; standard cells; types and design styles","en","journal article","","","","","","Accepted author manuscript","","2020-01-31","","","Materials and Manufacturing","","",""
"uuid:3b45f86a-8608-41bd-87d3-fbf1896bc2af","http://resolver.tudelft.nl/uuid:3b45f86a-8608-41bd-87d3-fbf1896bc2af","Active gust load alleviation of high-aspect ratio flexible wing aircraft","Ferrier, Yvonne L.; Nguyen, Nhan T. (NASA Ames Research Center); Ting, Eric (NASA Ames Research Center); Chaparro, Daniel (NASA Ames Research Center); Wang, Xuerui (TU Delft Control & Simulation); de Visser, C.C. (TU Delft Control & Simulation); Chu, Q. P. (TU Delft Control & Simulation)","","2018","This paper presents a novel active gust load alleviation approach within a multi-objective flight control framework developed by NASA for a flexible wing aircraft. The aircraft model is based on the NASA Generic Transport Model (GTM). The wing structures incorporate an aerodynamic control surface known as the Variable Camber Continuous Trailing Edge Flap (VCCTEF). Previous work already showed the ability of the VCCTEF to perform aeroelastic mode suppression, drag minimization and maneuver load alleviation in a multi-objective flight control framework. In this paper, the multi-objective flight control framework is extended to include active gust load alleviation. A Linear-Quadratic Gaussian (LQG) controller is augmented with Model Reference Adaptive Control (MRAC) to provide active gust load alleviation. Disturbance estimation is done using an Extended State Observer (ESO) to support the design of the active gust load alleviation controller. The results demonstrate the potential of active gust load alleviation within a multi-objective flight control framework for a high-aspect ratio flexible wing aircraft embodied with the VCCTEF.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","","","","Control & Simulation","","",""
"uuid:ed2399b2-1039-404f-a2ed-39e00a888b56","http://resolver.tudelft.nl/uuid:ed2399b2-1039-404f-a2ed-39e00a888b56","Spatial spillover effects of environmental pollution in China's Central Plains Urban Agglomeration","Xiong, Lichun (Beijing Forestry University); de Jong, W.M. (TU Delft Organisation & Governance; Fudan University); Wang, Fengting (China Agricultural University); Cheng, Baodong (Beijing Forestry University); Yu, Chang (Beijing Forestry University)","","2018","Promoting the rise of Central China is one of the most important national strategies regarding the promotion of China's economic development. However, the environmental issues in the central regions have become remarkably severe. It is therefore worthwhile exploring how economic development and environmental protection can be coordinated. Focusing on the 29 prefecture-level cities in the Central Plains Urban Agglomeration, the authors empirically analyze the relationship between the economy and the environment from 2004 to 2014. The combined methods of the spatial autocorrelation model, the environmental Kuznets curve, and the global spatial correlation test are systematically employed. The results show that: (1) a strong spatial correlation exists between industrial wastewater discharge, industrial sulfur dioxide, and dust emissions in the Central Plains Urban Agglomeration; (2) the relationship between the economy and the environment of this urban agglomeration reveals an inverted ""U"" curve, which confirms the classical environmental Kuznets curve hypothesis. Industrial dust emissions have surpassed the inflection point of the Kuznets curve, but its spatial spillover effect still remains strong. This is caused by an accumulation effect and a lag effect; (3) the proportion of the secondary industry and population has a strong positive effect on pollution discharge; investments in science and technology have a certain inhibitory effect on industrial sulfur dioxide emission. Moreover, an increase in the number of industrial enterprises has a negative effect on industrial wastewater emission. At the end, the authors put forward policy recommendations regarding the establishment of a joint supervisory department and unified environmental standards at the regional level to deal with the spillover effects of pollution.","Central PlainsUrbanAgglomeration; EnvironmentKuznets Curve; Spatial auto-correlationmodel","en","journal article","","","","","","","","","","","Organisation & Governance","","",""
"uuid:1d801d23-69ae-489f-989e-7cc131a08067","http://resolver.tudelft.nl/uuid:1d801d23-69ae-489f-989e-7cc131a08067","The Relative Biological Effect of Spread-Out Bragg Peak Protons in Sensitive and Resistant Tumor Cells","Lin, Yu-Fen (University of Texas Southwestern); Chen, Banjamin P. (University of Texas Southwestern); Li, Wende (Massachusetts General Hospital/Harvard Medical School); Perko, Z. (TU Delft RST/Reactor Physics and Nuclear Materials); Wang, Yi (Massachusetts General Hospital/Harvard Medical School); Testa, Mauro (Massachusetts General Hospital/Harvard Medical School); Robert, Schneider (Massachusetts General Hospital/Harvard Medical School); Lu, Hsaio-Ming (Massachusetts General Hospital/Harvard Medical School); Gerweck, Leo E. (Massachusetts General Hospital/Harvard Medical School)","","2018","Purpose: Variations in the radiosensitivity of tumor cells within and between tumors impact tumor response to radiation, including the dose required to achieve permanent local tumor control. The increased expression of DNA-PKcs, a key component of a major DNA damage repair pathway in tumors treated by radiation, suggests that DNA-PKcs– dependent repair is likely a cause of tumor cell radioresistance. This study evaluates the relative biological effect of spread-out Bragg-peak protons in DNA-PKcs–deficient cells and the same cells transfected with a functional DNA-PKcs gene. Materials and Methods: A cloned radiation-sensitive DNA-PKcs–deficient tumor line and its DNA-PKcs–transfected resistant counterpart were used in this study. The
presence of functional DNA-PKcs was evaluated by DNA-PKcs autophosphorylation.
Cells to be proton irradiated or x-irradiated were obtained from the same single cell suspension and dilution series to maximize precision. Cells were concurrently exposed to 6-MV x-rays or mid 137-MeV spread-out Bragg peak protons and cultured for colony formation. Results: The surviving fraction data were well fit by the linear-quadratic model for each of 8 survival curves. The results suggest that the relative biological effectiveness of mid spread-out Bragg peak protons is approximately 6% higher in DNA-PKcs–mediated resistant tumor cells than in their DNA-PKcs–deficient and radiation-sensitive counterpart.
Conclusion: DNA-PKcs–dependent repair of radiation damage is less capable of
repairing mid spread-out Bragg peak proton lesions than photon-induced lesions, suggesting protons may be more efficient at sterilizing DNA-PKcs–expressing cells that are enriched in tumors treated by conventional fractionated dose x-irradiation.","","en","journal article","","","","","","","","","","","RST/Reactor Physics and Nuclear Materials","","",""
"uuid:ff1e54e7-4395-4ef7-ab0c-c642d90174f8","http://resolver.tudelft.nl/uuid:ff1e54e7-4395-4ef7-ab0c-c642d90174f8","A Novel Rotated Antenna Array Topology for Near-Field 3-D Fully Polarimetric Imaging","Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Aubry, P.J. (TU Delft Microwave Sensing, Signals & Systems); Yarovoy, Alexander (TU Delft Microwave Sensing, Signals & Systems)","","2018","In this communication, a novel approach to rotated antenna array topology design is proposed for fully polarimetric short-range imaging. The rotated antenna array proposed acquires two co-pol and one cross-pol signals in terms of the “local” polarization basis by means of three antenna pairs. Then, the fully polarimetric signals in a global polarization basis are retrieved via simple polarization basis transformation, which overcomes the spatially varied polarizations of the signals acquired at different positions and makes valid the assumption of traditional imaging algorithms that the polarization is constant within the aperture. The proposed rotated antenna array takes advantage of the synthetic aperture technique to synthesize a 2-D array for 3-D full-pol imaging.
It utilizes a significantly smaller number of antennas in comparison to traditional fully polarimetric imaging arrays and also provides sufficiently accurate estimation to the full-pol electromagnetic signals scattered from targets. Both numerical simulations and experimental measurements have been performed and the results show the tolerance of the antenna array topology proposed to the quasi-monostatic measurements, its effectiveness, and accuracy for full-pol short-range microwave imaging.","Fully polarimetric imaging; microwave imaging; rotated array; signal retrieval/estimation; deband (UWB) radar","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","","","","Microwave Sensing, Signals & Systems","","",""
"uuid:fc403e7f-a91d-4190-a82c-b0c27841bbb8","http://resolver.tudelft.nl/uuid:fc403e7f-a91d-4190-a82c-b0c27841bbb8","MSE-impact of PPP-RTK ZTD estimation strategies","Wang, K. (Curtin University); Khodabandeh, A. (Curtin University); Teunissen, P.J.G. (TU Delft Mathematical Geodesy and Positioning; Curtin University)","","2018","In PPP-RTK network processing, the wet component of the zenith tropospheric delay (ZTD) cannot be precisely modelled and thus remains unknown in the observation equations. For small networks, the tropospheric mapping functions of different stations to a given satellite are almost equal to each other, thereby causing a near rank-deficiency between the ZTDs and satellite clocks. The stated near rank-deficiency can be solved by estimating the wet ZTD components relatively to that of the reference receiver, while the wet ZTD component of the reference receiver is constrained to zero. However, by increasing network scale and humidity around the reference receiver, enlarged mismodelled effects could bias the network and the user solutions. To consider both the influences of the noise and the biases, the mean-squared errors (MSEs) of different network and user parameters are studied analytically employing both the ZTD estimation strategies. We conclude that for a certain set of parameters, the difference in their MSE structures using both strategies is only driven by the square of the reference wet ZTD component and the formal variance of its solution. Depending on the network scale and the humidity condition around the reference receiver, the ZTD estimation strategy that delivers more accurate solutions might be different. Simulations are performed to illustrate the conclusions made by analytical studies. We find that estimating the ZTDs relatively in large networks and humid regions (for the reference receiver) could significantly degrade the network ambiguity success rates. Using ambiguity-fixed network-derived PPP-RTK corrections, for networks with an inter-station distance within 100 km, the choices of the ZTD estimation strategy is not crucial for single-epoch ambiguity-fixed user positioning. Using ambiguity-float network corrections, for networks with inter-station distances of 100, 300 and 500 km in humid regions (for the reference receiver), the root-mean-squared errors (RMSEs) of the estimated user coordinates using relative ZTD estimation could be higher than those under the absolute case with differences up to millimetres, centimetres and decimetres, respectively.","Mean-Squared Error (MSE); Mismodelled effects; Near rank-deficiency; PPP-RTK; Zenith Tropospheric Delay (ZTD)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","","","","Mathematical Geodesy and Positioning","","",""
"uuid:3e9873dd-a6d6-49d6-8fc5-57c0ab99acae","http://resolver.tudelft.nl/uuid:3e9873dd-a6d6-49d6-8fc5-57c0ab99acae","Current and future trends in topology optimization for additive manufacturing","Liu, Jikai (University of Pittsburgh); Gaynor, Andrew T. (U.S. Army Research Laboratory); Chen, Shikui (State University of New York); Kang, Zhan (Dalian University of Technology); Suresh, Krishnan (University of Wisconsin-Madison); Takezawa, Akihiro (Hiroshima University); Li, Lei (University of Notre Dame); Kato, Junji (Tohoku University); Tang, Jinyuan (Central South University); Wang, C.C. (TU Delft Materials and Manufacturing); Cheng, Lin (University of Pittsburgh); Liang, Xuan (University of Pittsburgh); To, Albert. C. (University of Pittsburgh)","","2018","Manufacturing-oriented topology optimization has been extensively studied the past two decades, in particular for the conventional manufacturing methods, for example, machining and injection molding or casting. Both design and manufacturing engineers have benefited from these efforts because of the close-to-optimal and friendly-to-manufacture design solutions. Recently, additive manufacturing (AM) has received significant attention from both academia and industry. AM is characterized by producing geometrically complex components layer-by-layer, and greatly reduces the geometric complexity restrictions imposed on topology optimization by conventional manufacturing. In other words, AM can make near-full use of the freeform structural evolution of topology optimization. Even so, new rules and restrictions emerge due to the diverse and intricate AM processes, which should be carefully addressed when developing the AM-specific topology optimization algorithms. Therefore, the motivation of this perspective paper is to summarize the state-of-art topology optimization methods for a variety of AM topics. At the same time, this paper also expresses the authors’ perspectives on the challenges and opportunities in these topics. The hope is to inspire both researchers and engineers to meet these challenges with innovative solutions.","Additive manufacturing; Lattice infill; Material feature; Multi-material; Post-treatment; Support structure; Topology optimization; Uncertainty","en","journal article","","","","","","Accepted author manuscript","","2019-06-30","","","Materials and Manufacturing","","",""
"uuid:d6a81a6c-ce0d-4f37-a7d6-c61f9b22a0f4","http://resolver.tudelft.nl/uuid:d6a81a6c-ce0d-4f37-a7d6-c61f9b22a0f4","Multi-Objective Performance Evaluation of the Detection of Catenary Support Components Using DCNNs","Liu, W. (Southwest Jiaotong University); Liu, Zhigang (Southwest Jiaotong University); Nunez, Alfredo (TU Delft Railway Engineering); Wang, Liyou (Southwest Jiaotong University); Liu, Kai (Southwest Jiaotong University); Lyu, Yang (Southwest Jiaotong University); Wang, H. (Southwest Jiaotong University)","De Schutter, Bart (editor); Ferrara, Antonella (editor)","2018","The goal of this paper is to evaluate from a multi-objective perspective the performance on the detection of catenary support components when using state-of-the-art deep convolutional neural networks (DCNNs). The detection of components is the first step towards a complete automatized monitoring system that will provide actual information about defects in the catenary support devices. A series of experiments in an unified test environment for detection of components are performed using Faster-CNN, R-FCN, SSD, and YOLOv2. Through the comparison of different assessment indicators, such as precision, recall, average precision and mean average precision, the detection performance of the different DCNNs methods for the components of the catenary support devices is analyzed, discussed and evaluated. The experiment results show that among all considered methods, R-FCN is the more suitable for the detection of catenary support components.","Catenary; Railway Systems; Multi-Objective Performance Evaluation; Deep convolutional neural networks (DCNNs","en","conference paper","","","","","","","","","","","Railway Engineering","","",""
"uuid:e0bb3ff6-e974-4aad-af5c-c8b9b80843fc","http://resolver.tudelft.nl/uuid:e0bb3ff6-e974-4aad-af5c-c8b9b80843fc","Air bubbles in fibrous caseinate gels investigated by neutron refraction, X-ray tomography and refractive microscope","Tian, B. (TU Delft RST/Neutron and Positron Methods in Materials); Wang, Zhaojun (Wageningen University & Research); van der Goot, Atze Jan (Wageningen University & Research); Bouwman, W.G. (TU Delft RST/Neutron and Positron Methods in Materials)","","2018","","","en","journal article","","","","","","","","","","","RST/Neutron and Positron Methods in Materials","","",""
"uuid:12c289e3-060c-4d6e-ae65-e868783389fb","http://resolver.tudelft.nl/uuid:12c289e3-060c-4d6e-ae65-e868783389fb","Induction healing of asphalt mixes with steel slag","Apostolidis, P. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Wang, H. (TU Delft Pavement Engineering); van de Ven, Martin (TU Delft Pavement Engineering); Scarpas, Athanasios (Khalifa University of Science and Technology)","Masad, Eyad (editor); Bhasin, Amit (editor); Scarpas, Tom (editor); Menapace, Ilaria (editor); Kumar, Anupam (editor)","2018","Asphaltic mixes are self-healing materials since they have the capacity to close internal microcracks at higher temperatures or under external force. To trigger their self-healing, asphalt mixes modified with inductive agents can be heated and in that way healed through applying alternating magnetic fields with the aid of an induction coil and this technique is named induction healing. This paper assesses the potential of implementing induction healing in an existing asphalt pavement with steel slag. Cores have been drilled from a field section of a mix with steel slag and were fatigue damaged in an indirect tensile test and healed via induction. The material induction healing potential has been visualized through different X-ray CT scans over the thickness of samples. The induction heating speed of asphalt mixes with steel slag was evaluated as well. The main conclusion in this study was that the total fatigue life of asphalt with steel slag can be enhanced with induction heating. The efficiency of micro-cracks closure was the same over the thickness of asphalt mixes and in combination with the high heating speed (~1.8 °C /sec), induction becomes a very promising alternative for various pavement operations.","","en","conference paper","CRC Press","","","","","","","","","","Pavement Engineering","","",""
"uuid:17f29ac9-95d6-4ed3-a70b-3ca326ffbe88","http://resolver.tudelft.nl/uuid:17f29ac9-95d6-4ed3-a70b-3ca326ffbe88","Rheological Behavior and Its Chemical Interpretation of Crumb Rubber Modified Asphalt Containing Warm-Mix Additives","Wang, H. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Apostolidis, P. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Khalifa University of Science and Technology)","","2018","The microstructure and chemical composition of asphalt binders have a significant effect on their rheological properties and, therefore, their performance as road paving binders. This study aims to investigate the effects of warm-mix asphalt (WMA) additives, organic type and chemical type, on the rheological properties and chemical internal structure of base asphalt and crumb rubber modified asphalt (CRMA). A set of dynamic shear rheometer (DSR) tests was conducted to obtain the rheological parameters (e.g., complex viscosity, complex modulus, phase angle) of asphalt binders. The flow activation energy was
calculated from Arrhenius equation based on viscosity data to rank the thermal susceptibility. Black diagrams and master curves of complex modulus and phase angle were utilized to analyze the rheological properties. The molecular weight distributions of asphalt binders were inverted from the phase angle master curve to evaluate the molecular weight characteristics. It was found that the the addition of crumb rubber into base asphalt improves the rheological properties of enhanced modulus and elasticity. Organic and chemical types of WMA additives have different chemo-physical effects on both base asphalt and CRMA. Phase angle inversion method provides a powerful tool to monitor the molecular structure change and, therefore, the chemo-physical interactions of asphalt binders induced by modifications. Finally, there is a good correlation between
flow activation energy and molecular weight","","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:7005d49f-4c41-442c-bf93-4541cec18dcb","http://resolver.tudelft.nl/uuid:7005d49f-4c41-442c-bf93-4541cec18dcb","A recognition model of driving risk based on Belief Rule-Base methodology","Sun, Chuan (Huanggang Normal University); Wu, Chaozhong (Wuhan University of Technology); Chu, Duanfeng (Wuhan University of Technology); Lu, Z. (TU Delft Intelligent Vehicles); Tan, Jian (Huanggang Normal University); Wang, Jianyu (Huanggang Normal University)","","2018","This paper aims to recognize driving risks in individual vehicles online based on a data-driven methodology. Existing advanced driver assistance systems (ADAS) have difficulties in effectively processing multi-source heterogeneous driving data. Furthermore, parameters adopted for evaluating the driving risk are limited in these systems. The approach of data-driven modeling is investigated in this study for utilizing the accumulation of on-road driving data. A recognition model of driving risk based on belief rule-base (BRB) methodology is built, predicting driving safety as a function of driver characteristics, vehicle state and road environment conditions. The BRB model was calibrated and validated using on-road data from 30 drivers. The test results show that the recognition accuracy of our proposed model can reach about 90% in all situations with three levels (none, medium, large) of driving risks. Furthermore, the proposed simplified model, which provides real-time operation, is implemented in a vehicle driving simulator as a reference for future ADAS and belongs to research on artificial intelligence (AI) in the automotive field.","ADAS; belief rule-base; data-driven; Driving data; vehicle driving risk","en","journal article","","","","","","","","","","","Intelligent Vehicles","","",""
"uuid:c151739e-716f-40e4-b1c7-66039ac7d643","http://resolver.tudelft.nl/uuid:c151739e-716f-40e4-b1c7-66039ac7d643","Data-driven hazardous gas dispersion modeling using the integration of particle filtering and error propagation detection","Zhu, Zhengqiu (National University of Defense Technology); Qiu, S. (TU Delft Web Information Systems; National University of Defense Technology); Chen, Bin (National University of Defense Technology); Wang, Rongxiao (National University of Defense Technology); Qiu, Xiaogang (National University of Defense Technology)","","2018","The accurate prediction of hazardous gas dispersion process is essential to air quality monitoring and the emergency management of contaminant gas leakage incidents in a chemical cluster. Conventional Gaussian-based dispersion models can seldom give accurate predictions due to inaccurate input parameters and the computational errors. In order to improve the prediction accuracy of a dispersion model, a data-driven air dispersion modeling method based on data assimilation is proposed by applying particle filter to Gaussian-based dispersion model. The core of the method is continually updating dispersion coefficients by assimilating observed data into the model during the calculation process. Another contribution of this paper is that error propagation detection rules are proposed to evaluate their effects since the measured and computational errors are inevitable. So environmental protection authorities can be informed to what extent the model output is of high confidence. To test the feasibility of our method, a numerical experiment utilizing the SF6 concentration data sampled from an Indianapolis field study is conducted. Results of accuracy analysis and error inspection imply that Gaussian dispersion models based on particle filtering and error propagation detection have better performance than traditional dispersion models in practice though sacrificing some computational efficiency.","Atmospheric dispersion; Data-driven modeling; Error propagation; Gaussian dispersion model; Particle filter; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Web Information Systems","","",""
"uuid:797864cd-050e-4a30-b269-3602f51b579a","http://resolver.tudelft.nl/uuid:797864cd-050e-4a30-b269-3602f51b579a","Morphodynamic impacts of large-scale engineering projects in the Yangtze River delta","Luan, Hualong (East China Normal University; Changjiang River Scientific Research Institute (CRSRI)); Ding, P (East China Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; East China Normal University; Deltares); Yang, S.L. (East China Normal University); Lu, Jin You (Changjiang River Scientific Research Institute (CRSRI))","","2018","Morphodynamics of world's river deltas are increasingly affected by human activities, which are of great ecological, economic and social implications. However, impacts of human interventions in deltaic regions are insufficiently
understood, especially superimposed upon diminishing sediment supplies. This study uses the heavily interfered Yangtze River delta as an example to address this issue. The morphodynamic impacts of the Deepwater Navigation Channel Project (DNCP) during 1997–2013 are investigated through process-based
modeling approach (Delft3D) and bathymetric data analysis. The DNCP was implemented in the mouth bar area of the Yangtze River delta including the twin dikes and 19 groynes with the total length of 132.0 km. Hydrodynamic simulations indicate that the training walls resulted in weaker tidal flow and longer slack period at the East Hengsha Shoal (EHS) and stronger tidal flow at the subaqueous delta. Thus, the EHS is characterized as a sediment accumulation zone after the completion of the training walls. Subsequently, morphological
modeling shows enhanced accretion at the EHS and enhanced erosion at the subaqueous delta when the training walls are taken into account. Numerical experiments further demonstrate that the above changes are mainly attributed to the seaward half of the northern training walls constructed in 2002–2005. This is probably the reason for the observed accretion peak of the EHS in 2002–2007 and the gradual increase in the erosion rate of the subaqueous delta after 2002. The schematized paths of sediment transport after the DNCP indicate that
sediment eroded from the subaqueous delta serves as an important source for accretion of the mouth bar area. It is suggested that siltation promoting projects within the mouth bar area increased shallow shoal accretion and aggravated erosion at the subaqueous delta. With the overall erosion of the Yangtze River delta due to river sediment reduction, large-scale estuarine engineering projects substantially increase the complicacy of its morphodynamic pattern, which merits close attention for sustainable delta management.","Morphodynamics; Estuarine engineering projects; Process-based modeling; Yangtze river delta","en","journal article","","","","","","","","2020-09-03","","","Coastal Engineering","","",""
"uuid:b3d3f3b7-532f-4902-8eaa-56fc2ef35d3f","http://resolver.tudelft.nl/uuid:b3d3f3b7-532f-4902-8eaa-56fc2ef35d3f","PowerFactory-Python based assessment of frequency and transient stability in power systems dominated by power electronic interfaced generation","Mola Jimenez, Jorge (Student TU Delft); Rueda, José L. (TU Delft Intelligent Electrical Power Grids); Perilla Guerra, A.D. (TU Delft Intelligent Electrical Power Grids); Wang, D. (TU Delft Intelligent Electrical Power Grids); Palensky, P. (TU Delft Intelligent Electrical Power Grids); van der Meijden, M.A.M.M. (TenneT TSO B.V.)","","2018","The deployment of variable renewable energy based power plants is increasing all over the world, however, unlike conventional power plants these are mostly connected to the grid via power electronic interfaces. High penetration of power electronic interfaced generation (PEIG) has an important impact on the inertia of the system, which is of major concern for frequency and large disturbance rotor angle (transient) stability. Therefore, it is desirable to study the effectiveness of widely used approaches to assess the stability of a system with high penetration of PEIG. This paper concerns with the modelling and control aspects of a power system for the evaluation of the most widely used metrics (indicators) to assess the dynamics of the power system related to frequency and rotor angle stability. The functionalities of Python are used to automate the generation of operational scenarios, the execution of time domain simulations, and the extraction of signal records to compute the aforesaid indicators. The paper also provides a discussion about possible improvements in the application of these indicators in monitoring tasks.","frequency stability; key performance indicators; power electronics interfaced generation; power system dynamics; transient stability; wind power","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-12-08","","","Intelligent Electrical Power Grids","","",""
"uuid:5000e635-e70a-42f0-bc8a-b5aefc1ef856","http://resolver.tudelft.nl/uuid:5000e635-e70a-42f0-bc8a-b5aefc1ef856","A condition-based maintenance methodology for rails in regional railway networks using evolutionary multiobjective optimization: Case study line Braşov to Zărneşti in Romania","Nunez, Alfredo (TU Delft Railway Engineering); Jamshidi, A. (TU Delft Railway Engineering); Wang, H. (TU Delft Railway Engineering); Hendriks, J.M. (TU Delft Railway Engineering); Ramirez Fonseca, I. (TU Delft Railway Engineering); Moraal, J. (TU Delft Railway Engineering); Dollevoet, R.P.B.J. (TU Delft Railway Engineering); Li, Z. (TU Delft Railway Engineering)","Vellasco, M. (editor); Estevez, P. (editor); Yen, Gary G. (editor)","2018","In this paper, we propose a methodology based on signal processing and evolutionary multiobjective optimization to facilitate the maintenance decision making of infra-managers in regional railways. Using a train in operation (with passengers onboard), we capture the condition of the rails using Axle Box Acceleration measurements. Then, using Hilbert-Huang Transform, the locations where the major risks are detected and ssessed with a degradation model. Finally,
evolutionary multiobjective optimization is employed to solve the maintenance decision problem, and to facilitate the visualization of the trade-offs between number of interventions and performance. Real-life measurements from the track from Braşov to Zărneşti in Romania are included to show the methodology.","Multiobjective optimization; acceleration measurements; Railway Engineering; ARMOEA; KPIs","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-01-13","","","Railway Engineering","","",""
"uuid:fbae5c23-b48c-4b00-8e71-b21807c87dbf","http://resolver.tudelft.nl/uuid:fbae5c23-b48c-4b00-8e71-b21807c87dbf","A new hermetic sealing method for ceramic package using nanosilver sintering technology","Zhang, H. (TU Delft Electronic Components, Technology and Materials; Changzhou Institute of Technology Research for Solid State Lighting); Liu, Yang (Harbin University of Science and Technology); Wang, Lingen (Boschman Technologies); Fan, Jiajie (Hohai University; Beijing Research Center; Changzhou Institute of Technology Research for Solid State Lighting); Fan, Xuejun (Lamar University; Changzhou Institute of Technology Research for Solid State Lighting); Sun, Fenglian (Harbin University of Science and Technology); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials; Changzhou Institute of Technology Research for Solid State Lighting)","","2018","High reliable packaging materials are needed for electronics when they work at harsh environments. Among which, the nanosilver material has been widely studied and applied in power electronics due to its low processing temperature and high reliability. This paper investigates the bonding properties of nanosilver sintered hermetic cavity. There are two kinds of lids used in this study, including copper lid and silicon lid. The X-ray and C-Mode Scanning Acoustic Microscopy (C-SAM) results revealed that delamination tended to happen in Cu lid sintered cavity as the recovery of deformed Cu lid was hindered by sintered dense Ag layer. However, no delamination or cracks were found in Si lid sintered cavity. Finite element analysis (FEA) method was used to investigate the effects of lid materials on the stress distribution of lid. The results indicated that the Cu lid sintered cavity showed a much higher stress than the Si lid sintered cavity under the sintering parameters of 250 °C and 10 MPa. There is no obvious change in the stress distribution areas on Cu lid with the increasing of pressures from 5 to 30 MPa. However, the distribution area of stress on Si lid expanded obviously only when the sintering pressure increased to 30 MPa. With the increase of sintering pressures from 5 to 30 MPa, the maximum stresses on Cu lid are almost the same, while increasing trend was found on Si lid.","Harsh environments; Nanosilver; Sintered; Lid; Stress","en","journal article","","","","","","Accepted author manuscript","","2020-01-04","","","Electronic Components, Technology and Materials","","",""
"uuid:9b8a77b0-ed9a-4254-9347-33f123fd66c4","http://resolver.tudelft.nl/uuid:9b8a77b0-ed9a-4254-9347-33f123fd66c4","Effect of Sintering Pressure on the Porosity and the Shear Strength of the Pressure-Assisted Silver Sintering Bonding","Liu, Yang (Harbin University of Science and Technology); Zhang, H. (Harbin University of Science and Technology); Wang, Lingen (Boschman Technologies); Fan, Xuejun (Lamar University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Sun, Fenglian (Harbin University of Science and Technology)","","2018","The microstructure, thickness, porosity, and shear performance of the silver (Ag) sintering layers under different sintering pressures were investigated. Experimental results demonstrated that the thickness and the porosity of the sintering layer decreased when the sintering pressure varied from 5 MPa to 30 MPa. This densification phenomenon facilitated the enhancement of the Ag sintering layers. The shear strength was improved significantly from 44.19 MPa to 69.41 MPa when the sintering pressure increased from 5 MPa to 10 MPa. When the sintering pressure ranged from 10 MPa to 30 MPa, the shear strength presented a slow increase from 69.41 MPa to 73.38 MPa. According to the results of the failure analysis, fracture mode transformation was considered as the basic reason for this phenomenon. The increasing sintering pressure promoted the bonding of the nano-Ag particles during the sintering process. Consequently, the fracture of the sintered-Ag layer transformed from brittle fracture to ductile fracture because of the increasing sintering pressure. The delamination area between Cu and Ni layers coated on the bottom Mo plate was clearly enlarged with the increasing sintering pressure. The delamination between Cu and Ni layers coated on the bottom Mo plate turned to be the main failure mode when the sintering pressure was higher than 10 MPa.","Reliability; sintering; porosity; strength; bonding","en","journal article","","","","","","Accepted author manuscript","","","","","Electronic Components, Technology and Materials","","",""
"uuid:09808c27-e933-4cf3-8629-a0bd66f404ea","http://resolver.tudelft.nl/uuid:09808c27-e933-4cf3-8629-a0bd66f404ea","Biocatalytic Oxidation Reactions: A Chemist's Perspective","Dong, J. (TU Delft BT/Biocatalysis); Fernandez Fueyo, E. (TU Delft BN/Greg Bokinsky Lab); Hollmann, F. (TU Delft BT/Biocatalysis); Paul, C.E. (TU Delft BT/Biocatalysis); Pesic, M. (TU Delft BT/Biocatalysis); Schmidt, S. (TU Delft BT/Biocatalysis); Wang, Yonghua (South China University of Technology); Younes, S.H.H. (TU Delft BT/Biocatalysis); Zhang, W. (TU Delft BT/Biocatalysis)","","2018","Oxidation chemistry using enzymes is approaching maturity and practical applicability in organic synthesis. Oxidoreductases (enzymes catalysing redox reactions) enable chemists to perform highly selective and efficient transformations ranging from simple alcohol oxidations to stereoselective halogenations of non‐activated C−H bonds. For many of these reactions, no “classical” chemical counterpart is known. Hence oxidoreductases open up shorter synthesis routes based on a more direct access to the target products. The generally very mild reaction conditions may also reduce the environmental impact of biocatalytic reactions compared to classical counterparts. In this Review, we critically summarise the most important recent developments in the field of biocatalytic oxidation chemistry and identify the most pressing bottlenecks as well as promising solutions.","German Edition :D OI:10.1002/ange.201800343 Bioc atalys is International Edition :DOI:10.1002/anie.201800343 Biocatalytic Oxidation Reactions :AChemist s Perspectiv e JiaJia Dong ,Elena Fern μ ndez-Fueyo ,Frank Hollmann,* Caroline E. Paul, Milja Pesic,Sandy Schmidt, Yonghua Wang,Sabry Younes,and Baeyer–Villiger oxidation; biocatalysis; halogenation; oxidation; oxyfunctionalisation","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:9848d77d-a98a-45c5-8077-aa3735d53f04","http://resolver.tudelft.nl/uuid:9848d77d-a98a-45c5-8077-aa3735d53f04","Production and immobilization of lipase PCL and its application in synthesis of α‐linolenic acid‐rich diacylglycerol","Liu, Nan (South China University of Technology); Liu, D. (South China University of Technology); Wang, Weifei (Guangdong Academy of Agricultural Sciences); Hollmann, F. (TU Delft BT/Biocatalysis); Xu, Long (South China University of Technology); Ma, Yunjian (South China University of Technology); Yang, Bo (South China University of Technology); Bai, Weidong (Zhongkai University of Agriculture and Engineering); Sun, Xiaotao (Beijing Technology and Business University); Wang, Yonghua (South China University of Technology)","","2018","α‐Linolenic acid‐rich diacylglycerol has been demonstrated with promising health promotion functions. This study examined the production, immobilization of lipase PCL, and its application in the synthesis of diacylglycerol by esterification of α‐linolenic acid with glycerol. The resin ECR8806 was selected as an effective support for the immobilization of lipase PCL. Fourier transform infrared and Laser scanning confocal microscope analysis proved that the lipase was successfully immobilized on the resin. Compared with the free PCL, the immobilized one exhibited higher temperature tolerance. Under optimized reaction conditions, a DAG content of 54.49% were obtained. After further purified by molecular distillation, the purity of DAG was up to 99.28%. During esterification, the immobilized PCL was quite stable and retained more than 91.60% of its initial activity after 10 cycles. These new findings on the immobilized PCL will make it to be a prospective enzyme in oils and fats industry.","diacylglycerol; esterification; immobilization; reusability; a-Linolenic acid","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-01-23","","","BT/Biocatalysis","","",""
"uuid:518b6034-1b68-426c-bd3f-980a84c17464","http://resolver.tudelft.nl/uuid:518b6034-1b68-426c-bd3f-980a84c17464","Ammonia/ionic liquid based double-effect vapor absorption refrigeration cycles driven by waste heat for cooling in fishing vessels","Wang, M. (TU Delft Engineering Thermodynamics); Becker, T. (TU Delft Engineering Thermodynamics); Schouten, Bob (Student TU Delft); Vlugt, T.J.H. (TU Delft Engineering Thermodynamics); Infante Ferreira, C.A. (TU Delft Engineering Thermodynamics)","","2018","To use high-temperature waste heat generated by diesel engines for onboard refrigeration of fishing vessels, an ammonia-based double-effect vapor absorption refrigeration cycle is proposed. Non-volatile ionic liquids are applied as absorbents in the double-effect absorption system. In comparison to systems using ammonia/water fluid, the complexity of the system can be reduced by preventing the use of rectification sections. In this study, a multi-scale method is implemented to study the proposed system, including molecular simulations (the Monte Carlo method) for computing vapor-liquid equilibrium properties at high temperatures and pressures, thermodynamic modeling of the double-effect absorption cycles, and system evaluations by considering practical integration. The Monte Carlo simulations provide reasonable vapor-liquid equilibrium predictions. 1-butyl-3-methylimidazolium tetrafluoroborate is found to be the best performing candidate among the investigated commercialized ionic liquids. In the proposed cycle, the best working fluid achieves a coefficient of performance of 1.1 at a cooling temperature of −5 C, which is slightly higher than that obtained with generator-absorber cycles. Integrated with the exhaust gas from diesel engines, the cooling capacity of the system is sufficient to operate two refrigeration seawater plants for most of the engine operating modes in high-latitude areas. Thereby, the carbon emission of onboard refrigeration of the considered fishing vessel could be reduced by 1633.5 tons per year compared to the current practice. Diagrams of vapor pressures and enthalpies of the studied working fluids are provided as appendices.","Double-effect absorption refrigeration cycle; Ionic liquid; Ammonia; Monte Carlo simulation; Fishing vessel; Waste heat recovery","en","journal article","","","","","","","","","","","Engineering Thermodynamics","","",""
"uuid:098a0959-f449-4c14-9276-ee1cf810b36c","http://resolver.tudelft.nl/uuid:098a0959-f449-4c14-9276-ee1cf810b36c","The relationship between inundation duration and Spartina alterniflora growth along the Jiangsu coast, China","Li, R. (TU Delft Coastal Engineering); Yu, Qian (Nanjing University); Wang, Yunwei (Hohai University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); Gao, Shu (East China Normal Univeristy); Flemming, Burg (Senckenberg Institute)","","2018","The above-ground biomass of Spartina alterniflora salt marsh meadows is influenced by numerous interacting factors, among them elevation, tidal range and inundation duration. Bio-geomorphological models make use of either linear or quadratic equations, but it is important to be aware that the variables are area specific and hence not generic. In order to explore the vegetation growth pattern and its influencing factors along the Jiangsu coast, China, field surveys were conducted in two typical S. alterniflora marshes along the coast of Dafeng and Rudong. To combine the influence of elevation and the effect of tidal range, the inundation ratio (IR) is introduced as a novel parameter, which is the ratio between inundation duration and the duration of the whole tidal period concerned. The relationship between above-ground biomass and IR can be expressed by a quadratic equation. The optimal inundation ratio for S. alterniflora along the Jiangsu coast ranges from 0.21 to 0.26, which is much lower than, for example, that for the marsh of North Inlet (0.35), South Carolina, and the Virginia Coast Reserve
(0.41), USA. Tidal range plays a significant role in that a larger tidal range leads to a smaller optimal IR, and that the landward and seaward limits are displaced toward higher ground elevations. In macrotidal regions the submergence depth is larger, which results in enhanced submergence and salinity stress for the entire marsh, causing it to shift toward higher elevations. Tidal range is an important factor influencing the growth pattern of S. alterniflora, but geomorphological factors such as topographic profiles, and the presence of cliffs and tidal creeks must also be taken into account.","Spartina alterniflora; Above-ground biomass; Inundation duration; Jiangsu coast","en","journal article","","","","","","","","2020-09-10","","","Coastal Engineering","","",""
"uuid:5609ed78-47f5-468a-97c0-65814153746a","http://resolver.tudelft.nl/uuid:5609ed78-47f5-468a-97c0-65814153746a","Morphodynamics of the Qiantang Estuary, China: Controls of river flood events and tidal bores","Xie, Dongfeng (Zhejiang Institute of Hydraulics and Estuary; Zhejiang Provincial Key Laboratory for Estuarine and Coastal Research); Pan, Cunhong (Zhejiang Institute of Hydraulics and Estuary; Zhejiang Provincial Key Laboratory for Estuarine and Coastal Research); Gao, Shu (East China Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2018","The importance of seasonal variations in river discharge on the morphological development of estuaries has been recognized in recent years, yet in situ observations about such variations are rare. Here we report a long-term dataset of bathymetry in the middle reach of the Qiantang Estuary, China, characterized by the presence of a large inner bar. Moreover, a hydrographic survey was carried out in the Yanguan reach where one of the largest tidal bores in the world occurs, covering a spring-neap tidal cycle in 2015. Meanwhile, detailed seasonal bathymetric data together with daily river discharges of 2015 were collected. The bed morphology shows strong seasonal and inter-annual variations. During the high flow season, the river flow erodes the bed and transports a large amount of sediments seaward. A good power-law relationship exists between the high river discharge and the channel volume at the upper estuary. Flood tides dominate under usual river flow condition. In particular, the tidal bore during spring and intermediate tides is characterized by large current velocity and high suspended sediment concentration, and transports a large amount of sediment landward. Over a year, a dynamic morphological equilibrium can be maintained. Moreover, the estuary has also been significantly influenced by the large-scale embankment in recent decades, constraining the lateral thalweg migration, bank erosion and point bar deposition, which usually occur in natural sinuous estuaries.","Morphodynamic equilibrium; Sediment transport; River discharge; Tidal bore; Qiantang Estuary; Hangzhou Bay","en","journal article","","","","","","","","2020-09-11","","","Coastal Engineering","","",""
"uuid:3d8ad1c0-4040-4297-956b-5f35a9ddea39","http://resolver.tudelft.nl/uuid:3d8ad1c0-4040-4297-956b-5f35a9ddea39","Organizational Effectiveness: Collaboration in an Integrated Project Team","Bakker, H.L.M. (TU Delft Integral Design & Management); Wang, Fan (Student TU Delft); Bosch-Rekveldt, M.G.C. (TU Delft Integral Design & Management); Eykelenboom, MG","","2018","Projects in the process industry are getting more complex from a technical as well as an organizational point of view. These projects can be considered as series of multi-phase and multi-discipline design and engineering activities involving contributions from many parties on many locations. In order to successfully perform such projects collaboration is required. This paper presents the results of studying a refinery revamp project. In this project the opportunity was offered to investigate the collaboration in the project team. Objective was to study the effectiveness of the organization in a multi-actor, multi-office and multi-discipline environment and identify potential areas for improving the collaboration. The method chosen was to study the business process model and combine this with a social network analysis (SNA) via observations, surveys and interviews. The differences shown in the comparison between the SNA and the business process model indicated areas where the collaboration could be improved. Furthermore, early identification of potential overload of people has been discovered from the social network analysis. SNA showed to be a powerful analysis method for investigating softer factors in projects, which is not yet common practice in the process industry.","","en","journal article","","","","","","","","","","","Integral Design & Management","","",""
"uuid:e20ee6db-ab55-4d4c-b26f-95f6ee751852","http://resolver.tudelft.nl/uuid:e20ee6db-ab55-4d4c-b26f-95f6ee751852","Regulatory supervision with computational audit in international supply chains","Wang, Y. (TU Delft ImPhys/Optics); Hulstijn, Joris (Tilburg University); Tan, Y. (TU Delft Information and Communication Technology)","Hinnant, C. (editor); Zuiderwijk, A. (editor)","2018","Nowadays, as international trade with cross-border logistics increases, the administrative burden of regulatory authorities has been dramatically raised. In order to reduce repetitive and redundant supervisory controls and promote automatic administration procedures, electronic data interchange (EDI) 1 and other forms of information sharing are introduced and implemented. Compliance monitoring ensures data quality for information exchange and audit purpose. However, failure to be compliant with various regulations is still a general phenomenon globally among stakeholders in supply chains, leading to more problems such as delay of goods delivery, missing inventory, and security issues. To address these problems, traditional physical auditing methods are widely used but turned out to be timeconsuming and costly, especially when multiple stakeholders are involved. Since there is limited empirical research on compliance monitoring for regulatory supervision in international supply chains, we propose a compliance monitoring framework that can be applied with data sharing and analytics. ""e framework implementation is validated by an extensive case study on customs supervision in the Netherlands using process mining techniques. Practically, both public and private sectors will benefit from our descriptive and prescriptive analytics for audit purposes. ""eoretically, our control strategies developed at the operational level facilitates mitigation of risks at root causes.","Audit; Compliance; Process mining; Regulatory supervision; Supply chains","en","conference paper","Association for Computing Machinery (ACM)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-12-01","","","ImPhys/Optics","","",""
"uuid:193eed47-c6fa-4093-8736-cbaef8af2915","http://resolver.tudelft.nl/uuid:193eed47-c6fa-4093-8736-cbaef8af2915","Scanning tunneling spectroscopy investigations of superconducting-doped topological insulators: Experimental pitfalls and results","Wilfert, Stefan (University of Würzburg); Sessi, Paolo (University of Würzburg); Wang, Zhiwei (University of Cologne); Schmidt, Henrik (University of Würzburg); Martinez Velarte, M.C. (TU Delft QN/Otte Lab); Lee, S.H. (The Pennsylvania State University; Missouri University of Science and Technology); Hor, Yew San (Missouri University of Science and Technology); Otte, A. F. (TU Delft QN/Otte Lab); Ando, Yoichi (University of Cologne); Wu, Weida (Rutgers University; University of Würzburg); Bode, Matthias (University of Würzburg)","","2018","Recently, the doping of topological insulators has attracted significant interest as a potential route towards topological superconductivity. Because many experimental techniques lack sufficient surface sensitivity, however, definite proof of the coexistence of topological surface states and surface superconductivity is still outstanding. Here we report on highly surface sensitive scanning tunneling microscopy and spectroscopy experiments performed on Tl-doped Bi2Te3, a three-dimensional topological insulator which becomes superconducting in the bulk at TC=2.3 K. Landau level spectroscopy as well as quasiparticle interference mapping clearly demonstrated the presence of a topological surface state with a Dirac point energy ED=-(118±1) meV and a Dirac velocity vD=(4.7±0.1)×105 m/s. Tunneling spectra often show a superconducting gap, but temperature- and field-dependent measurements show that both TC and μ0HC strongly deviate from the corresponding bulk values. Furthermore, in spite of a critical field value which clearly points to type-II superconductivity, no Abrikosov lattice could be observed. Experiments performed on normal-metallic Ag(111) prove that the gapped spectrum is caused only by superconducting tips, probably caused by a gentle crash with the sample surface during approach. Nearly identical results were found for the intrinsically n-type compound Nb-doped Bi2Se3. Our results suggest that the superconductivity in superconducting-doped V-VI topological insulators does not extend to the surface where the topological surface state is located.","","en","journal article","","","","","","","","","","","QN/Otte Lab","","",""
"uuid:51ebfb9e-6ac2-4189-8e0e-44d502ff786a","http://resolver.tudelft.nl/uuid:51ebfb9e-6ac2-4189-8e0e-44d502ff786a","Enhanced interconnection model in geographically interdependent networks","Rueda, Diego F. (University of Girona); Calle, Eusebi (University of Girona); Wang, X. (TU Delft Mathematical Physics); Kooij, Robert (TU Delft Network Architectures and Services)","","2018","Interconnection between telecommunication networks and other critical infrastructures is usually established through nodes that are spatially close, generating a geographical interdependency. Previous work has shown that in general, geographically interdependent networks are more robust with respect to cascading failures when the interconnection radius (r) is large. However, to obtain a more realistic model, the allocation of interlinks in geographically interdependent networks should consider other factors. In this paper, an enhanced interconnection model for geographically interdependent networks is presented. The model proposed introduces a new strategy for interconnecting nodes between two geographical networks by limiting the number of interlinks. Results have shown that the model yields promising results to maintain an acceptable level in network robustness under cascading failures with a decrease in the number of interlinks.","Cascading failures; Interdependent critical infrastructures; Region-based interconnection; Robustness","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:00387f74-f43c-484f-9c31-175148be7dcf","http://resolver.tudelft.nl/uuid:00387f74-f43c-484f-9c31-175148be7dcf","Modelling tidal-induced sediment transport in a sand-silt mixed environment from days to years: Application to the Jiangsu coastal water, China","Yao, P. (TU Delft Coastal Engineering; Sun Yat-sen University); Su, M. (TU Delft Coastal Engineering; Sun Yat-sen University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); van Rijn, L.C. (Leo van Rijn Sediment Consultancy); Zhang, Changkuan (Hohai University); Stive, M.J.F. (TU Delft Coastal Engineering)","","2018","In the present study a new multi-fractional, depth-averaged sediment transport module was developed and embedded into a morphodynamic model for a sand-silt mixed shallow water environment. Subsequently, the model was applied to the case of the Jiangsu coast, which features a silt enriched sedimentary environment bordered by two large-scale geomorphological units: the Old Yellow River Delta (OYRD) in the north and the Radial Sand Ridge Field (RSRF) in the south. Based on this case, the predictive abilities of the present model are
assessed on both the short-term and the long-term. Comparisons with measurements over two successive tidal cycles indicate that the present model produces very good results on short-time scales. The model performance is
extended and further validated by comparing the overall annual Suspended Sediment Concentration (SSC) pattern, the annual morphological changes, the annual sediment budget and the evolution trend of the bed composition. Also, these long-term results agree well with existing observations over the past several decades. Hence, an essential feature of the present modelling approach is the ability to simulate sediment transport and morphological changes over a relatively long time span (i.e., time scale of years) in a sand-silt mixed sedimentary environment, based on its validated short-term performance.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-03-15","","","Coastal Engineering","","",""
"uuid:24e0c72b-74e4-499c-a9d8-63c1c88c5844","http://resolver.tudelft.nl/uuid:24e0c72b-74e4-499c-a9d8-63c1c88c5844","Sediment budget and morphological development of the Dutch Wadden Sea: Impact of accelerated sea-level rise and subsidence until 2100","Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); Elias, Edwin P.L. (Deltares-USA); van der Spek, A.J.F. (Universiteit Utrecht; Deltares); Lodder, Q.J. (TU Delft Coastal Engineering; Ministry of Infrastructure and the Environment)","","2018","The Wadden Sea is a unique coastal wetland containing an uninterrupted stretch of tidal flats that span a distance of nearly 500 km along the North Sea coast from the Netherlands to Denmark. The development of this system is under pressure of climate change and especially the associated acceleration in sea-level rise (SLR). Sustainable management of the system to ensure safety against flooding of the hinterland, to protect the environmental value and to optimise the economic activities in the area requires predictions of the future morphological development.
The Dutch Wadden Sea has been accreting by importing sediment from the ebb-tidal deltas and the North Sea coasts of the barrier islands. The average accretion rate since 1926 has been higher than that of the local relative SLR. The large sediment imports are predominantly caused by the damming of the Zuiderzee and Lauwerszee rather than due to response to this rise in sea level. The intertidal flats in all tidal basins increased in height to compensate for SLR.
The barrier islands, the ebb-tidal deltas and the tidal basins that comprise tidal channels and flats together form a sediment-sharing system. The residual sediment transport between a tidal basin and its ebb-tidal delta through the tidal inlet is influenced by different processes and mechanisms. In the Dutch Wadden Sea, residual flow, tidal asymmetry and dispersion are dominant. The interaction between tidal channels and tidal flats is governed by both tides and waves. The height of the tidal flats is the result of the balance between sand supply by the tide and resuspension by waves.
At present, long-term modelling for evaluating the effects of accelerated SLR mainly relies on aggregated models. These models are used to evaluate the maximum rates of sediment import into the tidal basins in the Dutch Wadden Sea. These maximum rates are compared to the combined scenarios of SLR and extraction-induced subsidence, in order to explore the future state of the Dutch Wadden Sea.
For the near future, up to 2030, the effect of accelerated SLR will be limited and hardly noticeable. Over the long term, by the year 2100, the effect depends on the SLR scenarios. According to the low-end scenario, there will be hardly any effect due to SLR until 2100, whereas according to the high-end scenario the effect will be noticeable already in 2050.","Morphology; Sea-level rise; Sedimentation; Sediment budget; Wadden Sea","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:8ab241bd-269b-4b91-8f95-298e7ed99c42","http://resolver.tudelft.nl/uuid:8ab241bd-269b-4b91-8f95-298e7ed99c42","Support-Free Hollowing","Wang, Weiming (Dalian University of Technology); Liu, Yong-Jin (Tsinghua University); Wu, J. (TU Delft Materials and Manufacturing); Tian, Shengjing (Dalian University of Technology); Wang, C.C. (TU Delft Materials and Manufacturing); Liu, Ligang (University of Science and Technology of China); Liu, Xiuping (Dalian University of Technology)","","2018","Offsetting-based hollowing is a solid modeling operation widely used in 3D printing, which can change the model's physical properties and reduce the weight by generating voids inside a model. However, a hollowing operation can lead to additional supporting structures for fabrication in interior voids, which cannot be removed. As a consequence, the result of a hollowing operation is affected by these additional supporting structures when applying the operation to optimize physical properties of different models. This paper proposes a support-free hollowing framework to overcome the difficulty of fabricating voids inside a solid. The challenge of computing a support-free hollowing is decomposed into a sequence of shape optimization steps, which are repeatedly applied to interior mesh surfaces. The optimization of physical properties in different applications can be easily integrated into our framework. Comparing to prior approaches that can generate support-free inner structures, our hollowing operation can reduce more volume of material and thus provide a larger solution space for physical optimization. Experimental tests are taken on a number of 3D models to demonstrate the effectiveness of this framework.","shape optimization; support-free; hollowing; topology variation; 3D printing","en","journal article","","","","","","Accepted author manuscript","","","","","Materials and Manufacturing","","",""
"uuid:9f3425b3-287b-45a5-8392-e8143a8d7499","http://resolver.tudelft.nl/uuid:9f3425b3-287b-45a5-8392-e8143a8d7499","Delta DLP 3-D printing of large models","Yi, Ran (Tsinghua University); Wu, Chenming (Tsinghua University); Liu, Yong-Jin (Tsinghua University); He, Ying (Nanyang Technological University); Wang, C.C. (TU Delft Materials and Manufacturing)","","2018","This paper presents a 3-D printing system that uses a low-cost off-the-shelf consumer projector to fabricate large models. Compared with traditional digital light processing (DLP) 3-D printers using a single vertical carriage, the platform of our DLP 3-D printer using delta mechanism can also move horizontally in the plane. We show that this system can print 3-D models much larger than traditional DLP 3-D printers. The major challenge to realize 3-D printing of large models in our system comes from how to cover a planar polygonal domain by a minimum number of rectangles with fixed size, which is NP-hard. We propose a simple yet efficient approximation algorithm to solve this problem. The key idea is to segment a polygonal domain using its medial axis and afterward merge small parts in the segmentation. Given an arbitrary polygon Ω with n generators (i.e., line segments and reflex vertices in Ω), we show that the time complexity of our algorithm is O(n²log² n) and the number of output rectangles covering Ω is O(Kn), where K is an input-polygon-dependent constant. A physical prototype system is built and several large 3-D models with complex geometric structures have been printed as examples to demonstrate the effectiveness of our approach.","Manufacturing; mechanisms; primary topics; secondary topics","en","journal article","","","","","","Accepted author manuscript","","","","","Materials and Manufacturing","","",""
"uuid:87796e61-7687-4c5d-901b-3e239a3d0131","http://resolver.tudelft.nl/uuid:87796e61-7687-4c5d-901b-3e239a3d0131","A Dual Active Bridge Converter with an Extended High-Efficiency Range by DC Blocking Capacitor Voltage Control","Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Shen, Yanfeng (Aalborg University); Loh, Poh Chiang (The Chinese University of Hong Kong); Wang, Huai (Aalborg University); Blaabjerg, Frede (Aalborg University)","","2018","A Dual Active Bridge (DAB) converter can achieve a wide high-efficiency range when its input and output voltages are equal, assuming a 1:1 turns ratio for its isolation transformer. If its input or output voltage is doubled, efficiency of the DAB will drop significantly, because of the introduction of hard switching and high circulating power. Thus, a new modulation scheme has been proposed, whose main idea is to introduce a voltage offset across the dc blocking capacitor connected in series with the transformer. Operational principle of the proposed modulation has been introduced, before analyzing its soft-switching area and circulating power mathematically. The final modulation scheme is not difficult to implement, but can help the DAB achieve soft switching, low circulating power, and thereby high efficiency, even with its input or output voltage doubled.
These features have been verified by experimental results obtained with a 1.2 kW prototype.","dual active bridge; modulation; high efficiency; soft switching; circulating power","en","journal article","","","","","","Accepted Author Manuscript","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:6226ea2c-9462-4cdf-8d05-8fb963bed3d9","http://resolver.tudelft.nl/uuid:6226ea2c-9462-4cdf-8d05-8fb963bed3d9","In Light and In Darkness, In Motion and In Stillness: A Reliable and Adaptive Receiver for the Internet of Lights","Wang, Q. (TU Delft Embedded Systems); Giustiniano, Domenico (IMDEA Networks Institute); Zuniga, Marco (TU Delft Embedded Systems)","","2018","LEDs in our buildings, vehicles, and consumer products are rapidly gaining visible light communication capabilities. LED links however are notorious for being unreliable: shadowing, blockage, mobility, external light, all of these issues can disrupt the connectivity easily. Therefore, unless a reliable and cost-efficient data link layer is designed, VLC will be confined to niche applications. In this paper, we reveal a reason for unreliable VLC: a single type of photodetector at the receiver cannot establish a reliable link. We show that the photodetectors with complementary properties, in terms of optical spectral response and field-of-view, are necessary to handle the wide dynamic range of optical noise (such as the sun and other unwanted light sources) and mobility of users. Motivated by our experimental observations, we design a reliable and adaptive receiver for VLC (REAL-VLC) for low-end communication systems, an inexpensive receiver that senses light with complementary photodetectors and configures itself (physical and data link layers) dynamically to maintain the communication link. We implement the hardware and the software of REAL-VLC in low-end platforms, and experimentally validate it in representative test scenarios and a proofof-
concept application that consists of mobile nodes maintaining a VLC link under various lighting and path conditions.","Light emitting diodes; Optical receivers; Optical sensors; Optical transmitters; Photodetectors; Reliability; Design; Evaluation; FOV; Implementation; Internet of Lights; Reliable link; Spectral response; Tradeoff","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-08-17","","","Embedded Systems","","",""
"uuid:6f681b7d-4b4d-476e-8e48-e6553ed6728a","http://resolver.tudelft.nl/uuid:6f681b7d-4b4d-476e-8e48-e6553ed6728a","Automatic Defect Detection of Fasteners on the Catenary Support Device Using Deep Convolutional Neural Network","Chen, Junwen (Southwest Jiaotong University); Liu, Zhigang (Southwest Jiaotong University); Wang, H. (TU Delft Railway Engineering); Nunez, Alfredo (TU Delft Railway Engineering); Han, Zhiwei (Southwest Jiaotong University)","","2018","The excitation and vibration triggered by the long-term operation of railway vehicles inevitably result in defective states of catenary support devices. With the massive construction of high-speed electrified railways, automatic defect detection of diverse and plentiful fasteners on the catenary support device is of great significance for operation safety and cost reduction. Nowadays, the catenary support devices are periodically captured by the cameras mounted on the inspection vehicles during the night, but the inspection still mostly relies on human visual interpretation. To reduce the human involvement, this paper proposes a novel vision-based method that applies the deep convolutional neural networks (DCNNs) in the defect detection of the fasteners. Our system cascades three DCNN-based detection stages in a coarse-to-fine manner, including two detectors to sequentially localize the cantilever joints and their fasteners and a classifier to diagnose the fasteners' defects. Extensive experiments and comparisons of the defect detection of catenary support devices along the Wuhan-Guangzhou high-speed railway line indicate that the system can achieve a high detection rate with good adaptation and robustness in complex environments.","Automatic defect detection; Cameras; catenary support device; Computer architecture; deep convolutional neural network (DCNN); Detectors; fastener; Fasteners; Feature extraction; high-speed railway.; Rail transportation","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:7f313ebf-1702-4afb-84f1-da870e9db5c8","http://resolver.tudelft.nl/uuid:7f313ebf-1702-4afb-84f1-da870e9db5c8","Modeling of information diffusion on social networks with applications to WeChat","Liu, L. (TU Delft Multimedia Computing; National University of Defense Technology); Qu, B. (TU Delft Multimedia Computing); Chen, Bin (National University of Defense Technology); Hanjalic, A. (TU Delft Intelligent Systems); Wang, H. (TU Delft Multimedia Computing)","","2018","Traces of user activities recorded in online social networks open new possibilities to systematically understand the information diffusion process on social networks. From the online social network WeChat, we collected a large number of information cascade trees, each of which tells the spreading trajectory of a message/information such as which user creates the information and which users view or forward the information shared by which neighbors. In this work, we propose two heterogeneous non-linear models, one for the topologies of the information cascade trees and the other for the stochastic process of information diffusion on a social network. Both models are validated by the WeChat data in reproducing and explaining key features of cascade trees.
Specifically, we apply the Random Recursive Tree (RRT) to model the growth of cascade trees. The RRT model could capture key features, i.e. the average path length and degree variance of a cascade tree in relation to the number of nodes (size) of the tree. Its single identified parameter quantifies the relative depth or broadness of the cascade trees and indicates that information propagates via a star-like broadcasting or viral-like hop by hop spreading. The RRT model explains the appearance of hubs, thus a possibly smaller average path length as the cascade size increases, as observed in WeChat. We further propose the stochastic Susceptible View Forward Removed (SVFR) model to depict the dynamic user behavior including creating, viewing, forwarding and ignoring a message on a given social network. Beside the average path length and degree variance of the cascade trees in relation to their sizes, the SVFR model could further explain the power-law cascade size distribution in WeChat and unravel that a user with a large number of friends may actually have a smaller probability to read a message (s)he receives due to limited attention.","Information cascade; Stochastic model; Social networks; WeChat; Random recursive tree","en","journal article","","","","","","Accepted author manuscript","","2020-02-06","","Intelligent Systems","Multimedia Computing","","",""
"uuid:deb42044-2dbd-4050-a24a-18ec590ae5a6","http://resolver.tudelft.nl/uuid:deb42044-2dbd-4050-a24a-18ec590ae5a6","The Effects of Aeroelastic Tailoring on Flight Dynamic Stability","Natella, M. (TU Delft Aerospace Structures & Computational Mechanics); Wang, Xuerui (TU Delft Control & Simulation); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics)","","2018","This paper presents a unified framework for aeroelastic tailoring of free-flying aircraft with composite wings. A continuous-time state-space model is used to describe the flow. The 3D composite wing structures is condensed into a Timoshenko beam model by means of a cross-sectional modeler. The aerodynamic and structural models are closely coupled with the six degrees of freedom flight dynamic equations of motion in the state-space formulation. This paper refers to the clamped-wing aeroelastic tailoring as classic aeroelastic tailoring. Hence, the term aeroelastic tailoring will point at the novel approach that includes free-flying aeroelastic phenomena into the optimization process. The emphasis of the present paper is to show the effects of aeroelastic tailoring on body-freedom flutter and flight dynamic stability at large. The results of this paper will be used in the further development of aeroelastic tailoring practices for composite aircraft design.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-05","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:0795e7df-2fdc-4015-a34a-aee394e86cc0","http://resolver.tudelft.nl/uuid:0795e7df-2fdc-4015-a34a-aee394e86cc0","A DSC method for strict-feedback nonlinear systems with possibly unbounded control gain functions","Lv, Maolong (TU Delft Team Bart De Schutter; Air Force Engineering University); Wang, Ying (Air Force Engineering University); Baldi, S. (TU Delft Team Bart De Schutter); Liu, Zongcheng (Air Force Engineering University); Wang, Zutong (National Defence University)","","2018","In dynamic surface control (DSC) methods, the control gain functions of systems are always assumed to be bounded, which is a restrictive assumption. This work proposes a novel DSC approach for an extended class of strict-feedback nonlinear systems whose control gain functions are continuous and possibly unbounded. Appropriate compact sets are constructed in such a way that the trajectories of the closed-loop system do not leave these sets, therefore, in these sets, maximums and minimums values of the continuous control gain functions are well defined even if the control gain functions are possibly unbounded. By using Lyapunov theory and invariant set theory, semi-globally uniformly ultimately boundedness is analytically proved: all the signals of closed-loop system will always stay in these compact sets, while the tracking error is shown to converge to a residual set that can be made as small as desired by adjusting design parameters appropriately. Finally, the effectiveness of the designed method is demonstrated via two examples.","Adaptive neural control; Dynamic surface control; Invariant set theory; Robust control","en","journal article","","","","","","Accepted Author Manuscript","","2019-12-19","","","Team Bart De Schutter","","",""
"uuid:a7f1f393-d9d1-409f-9ae6-37dc13bb119d","http://resolver.tudelft.nl/uuid:a7f1f393-d9d1-409f-9ae6-37dc13bb119d","An analysis on half century morphological changes in the Changjiang Estuary: Spatial variability under natural processes and human intervention","Zhao, Jie (East China Normal University); Guo, Leicheng (East China Normal University); He, Qing (East China Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; East China Normal University; Deltares); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Deltares); Wang, X. (East China Normal University)","","2018","Examination of large scale, alluvial estuarine morphology and associated time evolution is of particular importance regarding management of channel navigability, ecosystem, etc. In this work, we analyze morphological evolution and changes of the channel-shoal system in the Changjiang Estuary, a river- and tide-controlled coastal plain estuary, based on bathymetric data between 1958 and 2016. We see that its channel-shoal pattern is featured by meandering and bifurcated channels persisting over decades. In the vertical direction, hypsometry curves show that the sand bars and shoals are continuously accreted while the deep channels are eroded, leading to narrower and deeper estuarine channels. Intensive human activities in terms of reclamation, embankment, and dredging play a profound role in controlling the decadal morphological evolution by stabilizing coastlines and narrowing channels. Even though, the present Changjiang Estuary is still a pretty wide and shallow system with channel width-to-depth ratios>1000, much larger than usual fluvial rivers and small estuaries. In-depth analysis suggests that the Changjiang Estuary as a whole exhibited an overall deposition trend over 59 years, i.e., a net deposition volume of 8.3×108m3. Spatially, the pan-South Branch was net eroded by 9.7×108m3 whereas the mouth bar zone was net deposited by 18×108m3, suggesting that the mouth bar zone is a major sediment sink. Over time there is no directional deposition or erosion trend in the interval though riverine sediment supply has decreased by 2/3 since the mid-1980s. We infer that the pan-South Branch is more fluvial controlled therefore its morphology responds to riverine sediment load reduction fast while the mouth bar zone is more controlled by both river and tides that its Morphological response lags to riverine sediment supply changes at a time scale>10 years, which is an issue largely ignored in previous studies. We argue that the time lag effect needs particular consideration in projecting future estuarine morphological changes under a low sediment supply regime and sea-level rise. Overall, the findings in this work can have implications on management of estuarine ecosystem, navigation channel and coastal flooding in general.","Changjiang Estuary; Morphological evolution; Sediment supply","en","journal article","","","","","","","","2020-03-05","","","Coastal Engineering","","",""
"uuid:2f15a1d4-bc86-450c-a6cc-26cfa225b417","http://resolver.tudelft.nl/uuid:2f15a1d4-bc86-450c-a6cc-26cfa225b417","Flexible Aircraft Gust Load Alleviation with Incremental Nonlinear Dynamic Inversion","Wang, Xuerui (TU Delft Control & Simulation); van Kampen, E. (TU Delft Control & Simulation); Chu, Q. P. (TU Delft Control & Simulation); De Breuker, R. (TU Delft Aerospace Structures & Computational Mechanics)","","2018","In this paper, an Incremental Nonlinear Dynamic Inversion (INDI) controller is
developed for the flexible aircraft gust load alleviation (GLA) problem. First, a flexible aircraft model captures both inertia and aerodynamic coupling effects between flight dynamics and structural vibration dynamics is presented. Then an INDI GLA controller is designed for this aircraft model based on sensor measurements and the Kalman filter online estimation. Besides, the fifth order Padé approximation is used to model the pure time delay in the state estimation. Furthermore, simulations of the flexible aircraft flying through various spatial turbulence and gust fields demonstrate the effectiveness of the proposed controller on rigid-body motion regulation, vertical load alleviation, wing root bending moment reduction and elastic modes suppression. Additionally, numerical perturbation tests and a Monte-Carlo study show the robustness of the proposed controller to aerodynamic model uncertainties.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-05","","","Control & Simulation","","",""
"uuid:d871c4f2-bc1a-4f70-9ebb-b75e9c1b04a9","http://resolver.tudelft.nl/uuid:d871c4f2-bc1a-4f70-9ebb-b75e9c1b04a9","Stability Analysis for Incremental Nonlinear Dynamic Inversion Control","Wang, Xuerui (TU Delft Control & Simulation); van Kampen, E. (TU Delft Control & Simulation); Chu, Q. P. (TU Delft Control & Simulation); Lu, P (Swiss Federal Institute of Technology)","","2018","As a sensor-based control approach, the Incremental Nonlinear Dynamic Inversion (INDI) method has been successfully applied on various aerospace systems and shown desirable robust performance to aerodynamic model uncertainties. However, its previous derivations based on the so-called time scale separation principle is not mathematically rigorous. There also
lack of stability and robustness analysis for INDI. Therefore, this paper reformulated the INDI control law without using the time scale separation principle and generalized it to not necessarily relative-degree-one problems, with consideration of the internal dynamics. Besides, the stability of the closed-loop system in the presence of external disturbances is analyzed using
Lyapunov methods and nonlinear system perturbation theory. Moreover, the robustness of the closed-loop system against regular and singular perturbations is analyzed. Finally, the reformulated INDI control law and main conclusions are verified by a rigid aircraft gust load alleviation problem.","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-01-05","","","Control & Simulation","","",""
"uuid:37a97768-f579-41ff-b48b-6be7f16f13ea","http://resolver.tudelft.nl/uuid:37a97768-f579-41ff-b48b-6be7f16f13ea","Road Network Design in a Developing Country Using Mobile Phone Data: An Application to Senegal","Wang, Y. (TU Delft Transport and Planning); Correia, Gonçalo (TU Delft Transport and Planning); de Romph, E. (TU Delft Transport and Planning; TNO); Santos, Bruno F. (TU Delft Air Transport & Operations)","","2018","This study uses mobile phone data to understand mobility patterns in a country, with limited mobility data, in order to give advice about decisions on how to design the national and regional road network. Our method consists of three parts: (1) filtering mobile phone traces to derive mobility patterns, (2) building an adapted formulation of the gravity-based trip distribution model, which considers telecommunication intensity (i.e., aggregate number of calls and text messages) and travel time as input to forecast the influence of road improvements on country-wide mobility, and (3) optimizing the road network investment based on the adapted trip distribution model by using a local search algorithm. The method was applied to the case study country of Senegal. The mobile phone data was transformed to support informed decisions on road network development in that country given different objectives, namely accessibility and equity. We believe that the methodology is valuable and reproducible to other countries where traditional mobility data is scarce but mobile phone data is available to transport planners.","Adaptation models; Mobile handsets; Planning; Predictive models; Roads; Sociology; Statistics","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-12-08","","","Transport and Planning","","",""
"uuid:3a166b5d-2315-4ab3-a684-c4c15ae28865","http://resolver.tudelft.nl/uuid:3a166b5d-2315-4ab3-a684-c4c15ae28865","A university building test case for occupancy-based building automation","Swaminathan, Siva (Student TU Delft); Wang, X. (TU Delft Team Bart De Schutter; China State Shipbuilding Corporation); Zhou, Bingyu (Siemens AG); Baldi, S. (TU Delft Team Bart De Schutter)","","2018","Heating, ventilation and air-conditioning (HVAC) units in buildings form a system-of-subsystems entity that must be accurately integrated and controlled by the building automation system to ensure the occupants' comfort with reduced energy consumption. As control of HVACs involves a standardized hierarchy of high-level set-point control and low-level Proportional-Integral-Derivative (PID) controls, there is a need for overcoming current control fragmentation without disrupting the standard hierarchy. In this work, we propose a model-based approach to achieve these goals. In particular: The set-point control is based on a predictive HVAC thermal model, and aims at optimizing thermal comfort with reduced energy consumption; the standard low-level PID controllers are auto-tuned based on simulations of the HVAC thermal model, and aims at good tracking of the set points. One benefit of such control structure is that the PID dynamics are included in the predictive optimization: in this way, we are able to account for tracking transients, which are particularly useful if the HVAC is switched on and off depending on occupancy patterns. Experimental and simulation validation via a three-room test case at the Delft University of Technology shows the potential for a high degree of comfort while also reducing energy consumption.","Demand side management; Heating ventilation and air-conditioning (hvac); Occupancy-based control; Optimization; Predicted mean vote (pmv)","en","journal article","","","","","","","","","","","Team Bart De Schutter","","",""
"uuid:46ef3f74-0cf8-4637-a215-f09084439cef","http://resolver.tudelft.nl/uuid:46ef3f74-0cf8-4637-a215-f09084439cef","Combined Effects of Unsteady River Discharges and Wave Conditions on River Mouth Bar Morphodynamics","Gao, Weilun (Beijing Normal University); Shao, Dongdong (Beijing Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; Beijing Normal University; Deltares); Nardin, William (University of Maryland); Yang, Wei (Beijing Normal University); Sun, Tao (Beijing Normal University); Cui, Baoshan (Beijing Normal University)","","2018","River mouth bar formation, a key process in fluvial-deltaic morphodynamics, is subject to both river discharge and waves. Given the increasing variability of both forcings under continuous climate change and human interventions, assessing their combined effects on mouth bar formatio n is an imperative issue. In this study, an extensive set of combined high and low river flows coupled with varying wave conditions and sediment grain sizes was assumed for numerical experiments conducted in Delft3D-SWAN. The results suggested that three regimes existed for mouth bar formation, namely, stable, ephemeral, and absent. These regimes corresponded to consistently weak, initially-weak-then-strong, and initially strong relative wave strengths, respectively, during the onset and reworking stages. Suppression of mouth bar formation further led to the inhibition of deltaic distributary networks. These findings have important implications for water and sediment management strategies, such as water diversion and dam regulation, in estuaries and deltas to prevent coastal erosion.","","en","journal article","","","","","","","","2019-07-01","","","Coastal Engineering","","",""
"uuid:c060783b-eb39-4a3b-9eb1-313fd0fe334d","http://resolver.tudelft.nl/uuid:c060783b-eb39-4a3b-9eb1-313fd0fe334d","Fast Phase-Only Positioning with Triple-Frequency GPS","Wang, Kan (Curtin University); Chen, Pei (Curtin University; Beihang University); Teunissen, P.J.G. (TU Delft Mathematical Geodesy and Positioning; Curtin University)","","2018","In this contribution, we study the phase-only ambiguity resolution and positioning performance of GPS for short baselines. It is well known that instantaneous (single-epoch) ambiguity resolution is possible when both phase and code (pseudorange) data are used. This requires, however, a benign multipath environment due to the severe effects multipath has on the code measurements. With phase-only processing, one would be free from such severe effects, be it that phase-only processing requires a change in receiver-satellite geometry, as a consequence of which it cannot be done instantaneously. It is thus of interest to know how much change in the relative receiver-satellite geometry is needed to achieve successful phase-only ambiguity resolution with correspondingly high precision baseline solutions. In this contribution, we study the two-epoch phase-only performance of single-, dual-, and triple-frequency GPS for varying time spans from 60 s down to 1 s. We demonstrate, empirically as well as formally, that fast phase-only very-precise positioning is indeed possible, and we explain the circumstances that make this possible. The formal analyses are also performed for a large area including Australia, a part of Asia, the Indian Ocean, and the Pacific Ocean. We remark that in this contribution ""phase-only"" refers to phase-only measurements in the observation model, while the code data are thus only used to compute the approximate values needed for linearizing the observation equations.","Ambiguity Dilution of Precision (ADOP); ambiguity resolution; GPS; phase-only; success-rate","en","journal article","","","","","","","","","","","Mathematical Geodesy and Positioning","","",""
"uuid:dde46a25-60c2-40f1-a7e0-5e879693fc90","http://resolver.tudelft.nl/uuid:dde46a25-60c2-40f1-a7e0-5e879693fc90","The Importance of Combined Tidal and Meteorological Forces for the Flow and Sediment Transport on Intertidal Shoals","de Vet, P.L.M. (TU Delft Environmental Fluid Mechanics; Deltares); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Schrijvershof, R. A. (Deltares); van der Werf, J. J. (Deltares; University of Twente); Ysebaert, T. (Universiteit Utrecht; Wageningen University & Research); Schrijver, M. C. (Ministry of Infrastructure and the Environment); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2018","Estuarine intertidal areas are shaped by combined astronomical and meteorological forces. This paper reveals the relative importance of tide, surge, wind, and waves for the flow and sediment transport on large intertidal shoals. Results of an intensive field campaign have been used to validate a numerical model of the Roggenplaat intertidal shoal in the Eastern Scheldt Estuary, the Netherlands, in order to identify and quantify the importance of each of the processes over time and space. We show that its main tidal creeks are not the cause for the dominant direction of the net flow on the shoal. The tidal flow over the shoal is steered by the water level differences between the surrounding channels. Also during wind events, the tidal flow (enhanced by surge) is dominant in the creeks. In contrast, wind speeds of order 40 times the typical tidal flow velocity are sufficient to completely alter the flow direction and magnitude on an intertidal shoal. This has significant consequences for the sediment transport patterns. Apart from this wind-driven flow dominance during these events, the wind also increases the bed shear stress by waves. For the largest intertidal part of the Roggenplaat, only ∼1–10% of the yearly transport results from the 50% least windy tides, even if the shoal is artificially lowered half the tidal range. This dominance of energetic meteorological conditions in the transports matches with field observations, in which the migration of the creeks and high parts of the shoal are in line with the predominant wind direction.","hydrodynamics; intertidal area; morphology; numerical model; sediment transport; wind","en","journal article","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:93d812f6-4f91-4854-8942-cf2a35832210","http://resolver.tudelft.nl/uuid:93d812f6-4f91-4854-8942-cf2a35832210","Super resolution DOA for FMCW automotive radar imaging","Xu, S. (TU Delft Microwave Sensing, Signals & Systems); Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Yarovoy, Alexander (TU Delft Microwave Sensing, Signals & Systems)","Pichot, C. (editor); Lindén, M. (editor); Petrovic, N. (editor)","2018","Radar imaging using ultra-wideband (UWB) automotive radar is investigated. To overcome poor cross-range resolution of traditional beamforming (BF) algorithms, super resolution technique is applied for the Direction of Arrival (DOA) estimation. Both super-resolution algorithm and conventional BF method are used to process experimental data collected with UWB frequency modulated continuous wave (FMCW) automo- tive radar. Algorithm performances are thoroughly compared.","","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","","","","Microwave Sensing, Signals & Systems","","",""
"uuid:11473b8b-33da-49f6-8a78-83aff6f0072c","http://resolver.tudelft.nl/uuid:11473b8b-33da-49f6-8a78-83aff6f0072c","Synthesis of stable and low-Co2 selective Ɛ-iron carbide Fischer-Tropsch catalysts","Wang, Peng (National Institute of Clean-and-Low-Carbon Energy, Shenhua NICE, Future Science and Technology City, Changping District, Beijing 102211, People's Republic of China; Eindhoven University of Technology); Chen, Wei (Eindhoven University of Technology); Chiang, Fu-Kuo (National Institute of Clean-and-Low-Carbon Energy, Shenhua NICE, Future Science and Technology City, Changping District, Beijing 102211, People's Republic of China); Dugulan, A.I. (TU Delft RST/Fundamental Aspects of Materials and Energy); Song, Yuanjun (University of Science and Technology Beijing); Pestman, Robert (Eindhoven University of Technology); Zhang, Kui (National Institute of Clean-and-Low-Carbon Energy, Shenhua NICE, Future Science and Technology City, Changping District, Beijing 102211, People's Republic of China); Yao, Jinsong (National Institute of Clean-and-Low-Carbon Energy, Shenhua NICE, Future Science and Technology City, Changping District, Beijing 102211, People's Republic of China); Feng, Bo (National Institute of Clean-and-Low-Carbon Energy, Shenhua NICE, Future Science and Technology City, Changping District, Beijing 102211, People's Republic of China); Miao, Ping (National Institute of Clean-and-Low-Carbon Energy, Shenhua NICE, Future Science and Technology City, Changping District, Beijing 102211, People's Republic of China); Xu, Wayne (National Institute of Clean-and-Low-Carbon Energy, Shenhua NICE, Future Science and Technology City, Changping District, Beijing 102211, People's Republic of China); Hensen, Emiel J.M. (Eindhoven University of Technology)","","2018","","","en","journal article","","","","","","","","","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:6ef727ec-9b66-46d3-9b62-c36f26fac65e","http://resolver.tudelft.nl/uuid:6ef727ec-9b66-46d3-9b62-c36f26fac65e","An integrated operational system to reduce O&M cost of offshore wind farms","Wang, K. (TU Delft Transport Engineering and Logistics; Wuhan University of Technology); Jiang, X. (TU Delft Transport Engineering and Logistics); Negenborn, R.R. (TU Delft Transport Engineering and Logistics); Yan, X. (Wuhan University of Technology); Yuan, Y. (Wuhan University of Technology)","Guedes Soares, Carlos (editor); Santos, T.A. (editor)","2018","Offshore wind is a relatively new industry and it is generally more expensive to generate electricity than many alternative renewable sources. Operation & Maintenance (O&M) makes up a significant part of the overall cost of running Offshore Wind Turbines (OWT). Since the O&M associated responsibility is shared among turbine manufacturers, wind farm operators and the offshore transmission owners, this has inevitably led to lack of information, duplication of effort and less efficiency. Big data analytics is one great technique that will drive future growth. In this paper, an integrated operational system of offshore wind farm is proposed deploying big data analytics. Firstly, the current state of the O&M of offshore wind farm and the big data analytics are introduced. Afterwards, a predictive maintenance model and a maintenance implementation model are proposed, and an integrated operational system is developed incorporating those two models in order to optimize maintenance planning and implementation. Finally, the possible contribution of such a system to a more effective O&M of offshore wind farm is discussed.","","en","conference paper","CRC Press / Balkema - Taylor & Francis Group","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-10-16","","","Transport Engineering and Logistics","","",""
"uuid:6c83bfc3-a1b8-4ec2-8274-29ec38853207","http://resolver.tudelft.nl/uuid:6c83bfc3-a1b8-4ec2-8274-29ec38853207","Biocatalytic synthesis of lactones and lactams","Hollmann, F. (TU Delft BT/Biocatalysis); Kara, Selin (Aarhus University); Opperman, Diederik J. (University of the Free State); Wang, Yonghua (South China University of Technology)","","2018","Cyclic esters and amides (lactones and lactams) are important active ingredients and polymer building blocks. In recent years, numerous biocatalytic methods for their preparation have been developed including enzymatic and chemoenzymatic Baeyer–Villiger oxidations, oxidative lactonisation of diols, and reductive lactonisation and lactamisation of ketoesters. The current state of the art of these methods is reviewed.","Baeyer–Villiger oxidation; biocatalysis; lactams; lactones; oxidative Lactonisation","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:bb492bb2-3700-4224-8ee3-3b70ce87be91","http://resolver.tudelft.nl/uuid:bb492bb2-3700-4224-8ee3-3b70ce87be91","Asphalt-rubber interaction and performance evaluation of rubberised asphalt binders containing non-foaming warm-mix additives","Wang, H. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Zhang, H. (TU Delft Pavement Engineering); Apostolidis, P. (TU Delft Pavement Engineering); Scarpas, Athanasios (TU Delft Pavement Engineering; Petroleum Institute); Erkens, S. (TU Delft Pavement Engineering)","","2018","Warm mix asphalt (WMA) technology has been increasingly utilised in rubberised asphalt pavements to reduce the production and compaction temperatures and the incidental fumes and odours. This study aims to investigate the high, intermediate and low-temperature performance of crumb rubber modified asphalt binders containing WMA additives. The asphalt-rubber interactions under various mixing combinations of temperature and time were investigated through both microscopic and mechanical methods to obtain the optimum mixing procedure. The effects of WMA additives (wax-based and chemical-based products) on the binder performance were investigated by multiple stress creep and recovery (MSCR) test, linear amplitude sweep (LAS) test and low-temperature frequency sweep test. Results show that rubberised asphalt binders significantly improve the binder performance of base asphalt at different temperature ranges. The effects of WMA additives on binder performance varied with base asphalt and rubberised asphalt binder. In addition, the nonrecoverable compliance difference was found not suitable to characterise the stress sensitivity of rubberised binders and the difference in the nonrecoverable compliance for an incremental change in applied stress was proved to be a more accurate alternative. For the cyclic LAS test, the failure energy was found to have a strong correlation with the predicted fatigue life using simplified viscoelastic continuum damage analysis and therefore can be considered as a simple indicator for binder fatigue performance ranking. Relaxation modulus and rate derived from low-temperature frequency sweep tests produced comparable results for ranking the low-temperature performance of different binders. It is feasible and promising to use a unified DSR test methodology to characterise the binder performance covering the whole service temperature range.","crumb rubber modifier; frequency sweep; LAS; MSCR; warm mix asphalt","en","journal article","","","","","","","","2020-01-01","","","Pavement Engineering","","",""
"uuid:0b9a68ab-cb71-426d-9adb-bd15352c75d7","http://resolver.tudelft.nl/uuid:0b9a68ab-cb71-426d-9adb-bd15352c75d7","Improved Microwave Imaging by Wavenumber Domain Multiband Data Fusion","Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Aubry, P.J. (TU Delft Microwave Sensing, Signals & Systems); Yarovoy, Alexander (TU Delft Microwave Sensing, Signals & Systems)","","2018","A matrix-pencil based wavenumber-domain multiband fusion approach is proposed for improved microwave imaging. The suggested fusion approach is based on the fact from the Born approximation that the wavenumber-domain signal in a given scattering direction can be represented as a sum of the same number of contributions over the whole bandwidth. Utilizing this fact, the wavenumber-domain signal in each radial direction can be modeled as a superposition of damped/undamped exponential functions, where measured multiband data are part of the observations of the whole-band signal. Then the multiband signal fusion is addressed by estimating a unified signal model over the while bandwidth with the matrix pencil approach in the wavenumber domain. By using the estimated signal model, the missing data in the frequency gap can be extrapolated, thus synthesizing an equivalent wideband signal spectrum. After an inverse Fourier transform, the synthesize spectrum leads to a focused image with enhanced resolution. Compared to the existing frequency-domain method, the proposed fusion approach can be used for radar imaging with the signals acquired by either collocated or non-collocated arrays in different frequency bands. The effectiveness and accuracy of the proposed fusion approach are demonstrated through some numerical simulations.","","en","conference paper","IEEE","","","","","green","","","","","Microwave Sensing, Signals & Systems","","",""
"uuid:fd47c799-c03f-4018-9653-a1463ba93534","http://resolver.tudelft.nl/uuid:fd47c799-c03f-4018-9653-a1463ba93534","3D Cadastres Best Practices, Chapter 5: Visualization and New Opportunities","Pouliot, Jacynthe (Université Laval); Ellul, Claire (University College London (UCL)); Hubert, Frederic (Université Laval); Wang, Chen (Anhui University); Rajabifard, Abbas (University of Melbourne); Kalantari, Mohsen (University of Melbourne); Shojaei, Davood (Land Use Victoria); Atazadeh, Behnam (University of Melbourne); van Oosterom, P.J.M. (TU Delft OLD Department of GIS Technology); de Vries, M.E. (TU Delft OLD Department of GIS Technology); Ying, Shen (Wuhan University)","","2018","This paper proposes a discussion on opportunities offered by 3D visualization to improve the understanding and the analysis of cadastre data. It first introduce the rationale of having 3D visualization functionalities in the context of cadastre applications. Second the publication outline some basic concepts in 3D visualization. This section specially addresses the visualization pipeline as a driven classification schema to understand the steps leading to 3D visualization. In this section is also presented a brief review of current 3D standards and technologies. Next is proposed a summary of progress made in the last years in 3D cadastral visualization. For instance, user’s requirement, data and semiotics, and platforms are highlighted as main actions performed in the development of 3D cadastre visualization. This review could be perceived as an attempt to structure and emphasise the best practices in the domain of 3D cadastre visualization and as an inventory of issues that still need to be tackled. Finally, by providing a review on advances and trends in 3D visualization, the paper initiates a discussion and a critical analysis on the benefit of applying these new developments to cadastre domain. This final section discusses about enhancing 3D techniques as dynamic transparency and cutaway, 3D generalization, 3D visibility model, 3D annotation, 3D data and web platform, augmented reality, immersive virtual environment, 3D gaming, interaction techniques and time.","3D Cadastral Visualization; Users; User Requirements; Usability; Modelling; Presenting Information; 3D Environments; Interaction","en","conference paper","International Federation of Surveyors (FIG)","","","","","","","","","","OLD Department of GIS Technology","","",""
"uuid:c16fa090-4953-4a08-ad1f-0834efef1f3a","http://resolver.tudelft.nl/uuid:c16fa090-4953-4a08-ad1f-0834efef1f3a","The impact of on-demand service schemes provided by a fleet of shared autonomous vehicles","Wang, S. (TU Delft Transport and Planning; TU Delft Mathematical Physics); Correia, Gonçalo (TU Delft Transport and Planning); Lin, H.X. (TU Delft Mathematical Physics)","","2018","The introduction of the concept of a fleet of shared autonomous vehicle (SAVs) which function as a centralized taxi service system presents an innovative way in transport modes. A fleet of SAVs can provide tailored on-demand services via a centralized operation to serve travel demand over time. In our study, An agent-based model (ABM) is developed to simulate tailored time-varying service (TVS) provided by a fleet of SAVs in a demand-responsive fashion. The proposed system can switch the service scheme between the door-to-door service (DDS) and station-to-station service (SSS) automatically based on the time of day; In peak hours, the SAV system aims to serve as many trips as possible with predesignated stations as a SSS by providing an on-demand service. In o-peak hours, a DDS in a demand-responsive fashion is provided by a fleet of SAVs
which can benet the travelers with great convenience. Also, DDS and
SSS provided by SAVs in a demand responsive fashion are simulated separately. The potential benets of TVS provided by SAVs are investigated and then compare it with DDS and SSS. The simulation results indicate that the tailored TVS can increase the utilization of SAVs by 2.5% and number of passengers transported per days by 2.9%. Compared with DDS in peak hours, there are reductions of averaging waiting time and energy consumption up to 25.5 % and 3.7% respectively. In o-peak hour, the TVS can be easily employed to eliminate the avearge 9-minute walking time of the SSS. In addition, we nd out that there is a signicant increase of trips by empty SAVs at around 82% for all service schemes. It is an important issue for further investigation.","Shared autonomous vehicles; on-demand service; quality of service; agent-based model","en","conference paper","","","","","","","","","","","Transport and Planning","","",""
"uuid:43b01ad5-c435-465e-816e-e1755b48ab96","http://resolver.tudelft.nl/uuid:43b01ad5-c435-465e-816e-e1755b48ab96","The data and services analysis of Chinese NSDI based on Backx model","Wang, Wei (Tianjin Institute of Surveying and Mapping); Xue, Mei (Chongqing Surveying Institute); Luo, Chengfeng (Chinese Academy of Surveying and Mapping); Wang, Xiaomeng (Beijing Urban Planning and Land Resource Committee); van Loenen, B. (TU Delft OLD Geo-information and Land Development)","Jiang, J. (editor); Shaker, A. (editor); Zhang, H. (editor); Liang, X. (editor); Osmanoglu, B. (editor); , et al. (editor)","2018","The data and services analysis are indispensable for the refined development of SDI. This paper, taking Chinese NSDI as a study case, analyzed the data and services advantages and shortcomings of Chinese NSDI and developed a recommendable data and services framework which could improve the Chinese NSDI better services for public and private sectors from known, attainable and usable aspects by using Backx model. And the recommendation framework can also be referenced by other national and local SDI for its better services and applications.","Data and Service Analysis; Chinese NSDI; Backx Model","en","conference paper","","","","","","","","","","","OLD Geo-information and Land Development","","",""
"uuid:5e296945-5638-44ba-a1ca-14175c2029e4","http://resolver.tudelft.nl/uuid:5e296945-5638-44ba-a1ca-14175c2029e4","A systematic review of non-pharmacological interventions for BPSD in nursing home residents with dementia: From a perspective of ergonomics","Wang, G. (TU Delft Applied Ergonomics and Design); Albayrak, A. (TU Delft Applied Ergonomics and Design); van der Cammen, T.J.M. (TU Delft Applied Ergonomics and Design; Erasmus MC; Brighton and Sussex Medical School)","","2018","Background:
Non-pharmacological interventions for Behavioral and Psychological Symptoms of Dementia (BPSD) have been developed; however, a systematic review on the effectiveness of this type of intervention from a perspective of ergonomics is lacking. According to ergonomics, the capabilities of Persons with Dementia (PwD) should be considered in the interventions for the outcomes to be reliable. We aimed to systematically review the non-pharmacological interventions for BPSD in nursing home residents with an additional assessment criterion based on ergonomics, specifically, capability consideration.
Methods:
The electronic databases MEDLINE, EMBASE, and PsycINFO were searched for non-pharmacological interventions treating BPSD in nursing homes. The interventions were categorized according to the capabilities of PwD required to participate. Study quality was assessed by National Health and Medical Research Council (NHMRC) evidence hierarchy and the capability consideration.
Results:
Sixty-four clinical trials met the inclusion criteria; 41 trials reported a significant reduction in at least one BPSD symptom; 20 trials reported no significant reduction in BPSD symptoms; three trials reported adverse effects after the intervention. Interventions were categorized into sensory-, cognition-, and movement-oriented. Capabilities of PwD were not considered in 28 trials, especially for sensory capabilities.
Conclusions:
The majority of the clinical trials reported a significant reduction in BPSD. The quality of evidence for nonpharmacological interventions in these trials is low due to the lack of capability consideration, data inhomogeneity, and inadequate study design and reporting. Future studies should focus on improving the quality of evidence by including capability consideration and examining if a relationship between capability consideration and effectiveness of non-pharmacological interventions exists.
2 capture","Shan, M. (TU Delft ChemE/Catalysis Engineering; TU Delft ChemE/Transport Phenomena); Liu, X. (TU Delft ChemE/Catalysis Engineering); Wang, X. (TU Delft ChemE/Catalysis Engineering); Yarulina, I. (TU Delft ChemE/Catalysis Engineering; King Abdullah University of Science and Technology); Seoane, Beatriz (TU Delft ChemE/Catalysis Engineering; Debye Institute); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering); Gascon, Jorge (TU Delft ChemE/Catalysis Engineering; King Abdullah University of Science and Technology)","","2018","The development of new membranes with high H2 separation performance under industrially relevant conditions (high temperatures and pressures) is of primary importance. For instance, these membranes may facilitate the implementation of energy-efficient precombustion CO2 capture or reduce energy intensity in other industrial processes such as ammonia synthesis. We report a facile synthetic protocol based on interfacial polymerization for the fabrication of supported benzimidazole-linked polymer membranes that display an unprecedented H2/CO2 selectivity (up to 40) at 423 K together with high-pressure resistance and long-term stability (>800 hours in the presence of water vapor).","","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:813e08e7-6925-4781-b89c-aded3f65448e","http://resolver.tudelft.nl/uuid:813e08e7-6925-4781-b89c-aded3f65448e","Copper adparticle enabled selective electrosynthesis of n-propanol","Li, Jun (University of Toronto); Che, Fanglin (University of Toronto); Pang, Yuanjie (University of Toronto); Zou, Chengqin (University of Toronto; Tianjin University); Howe, Jane Y. (Hitachi High Technologies America, Inc.); Burdyny, T.E. (TU Delft ChemE/Materials for Energy Conversion and Storage; University of Toronto); Edwards, Jonathan P. (University of Toronto); Wang, Yuhang (University of Toronto); Li, Fengwang (University of Toronto); Wang, Ziyun (University of Toronto)","","2018","The electrochemical reduction of carbon monoxide is a promising approach for the renewable production of carbon-based fuels and chemicals. Copper shows activity toward multi-carbon products from CO reduction, with reaction selectivity favoring two-carbon products; however, efficient conversion of CO to higher carbon products such as n-propanol, a liquid fuel, has yet to be achieved. We hypothesize that copper adparticles, possessing a high density of under-coordinated atoms, could serve as preferential sites for n-propanol formation. Density functional theory calculations suggest that copper adparticles increase CO binding energy and stabilize two-carbon intermediates, facilitating coupling between adsorbed *CO and two-carbon intermediates to form three-carbon products. We form adparticle-covered catalysts in-situ by mediating catalyst growth with strong CO chemisorption. The new catalysts exhibit an n-propanol Faradaic efficiency of 23% from CO reduction at an n-propanol partial current density of 11 mA cm−2.","","en","journal article","","","","","","Correction:The original version of this Article incorrectly omitted the received/accepted dates of Received: 05 June 2018; Accepted: 10 October2018. This has now been corrected in the PDF and HTML versions of the Article with 10.1038/s41467-020-14883-z","","","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:b446cc7c-5e63-4793-985c-6a914a32ce8f","http://resolver.tudelft.nl/uuid:b446cc7c-5e63-4793-985c-6a914a32ce8f","Range image technique for change analysis of rock slopes using dense point cloud data","Shen, Y. (TU Delft Optical and Laser Remote Sensing; Hohai University); Wang, Jinguo (Hohai University); Lindenbergh, R.C. (TU Delft Optical and Laser Remote Sensing); Hofland, Bas (TU Delft Hydraulic Structures and Flood Risk); Ferreira, Vagner G. (Hohai University)","","2018","The use of a terrestrial laser scanner is examined to measure the changes of rock slopes subject to a wave attack test. Real scenarios are simulated in a water flume facility using a wave attack experiment representing a storm of 3000 waves. The stability of two rock slopes of different steepness was evaluated under the set conditions. For quantification of the changes of the slopes after the wave attack test, terrestrial laser scanning was used to acquire dense 3D point cloud data sampling for slope geometries before and after the wave attack experiment. After registration of the two scans, representing situations before and after the wave attack, the cloud-to-cloud distance was determined to identify areas in the slopes that were affected. Then, a range image technique was introduced to generate a raster image to facilitate a change analysis. Using these raster images, volume change was estimated as well. The results indicate that the area around the artificial coast line is most strongly affected by wave attacks. Another interesting phenomenon considers the change in transport direction of the rocks between the two slopes: from seaward transport for the steeper slope to landward transport for the milder slope. Using the range image technique, the work in this article shows that terrestrial laser scanning is an effective and feasible method for change analysis of long and narrow rock slopes.","Change analysis; Range image; Rock slopes; TLS; Wave attack simulation","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:255b1395-e3b9-43a9-a27f-348af4ba4044","http://resolver.tudelft.nl/uuid:255b1395-e3b9-43a9-a27f-348af4ba4044","The influence of CO2 on NO reduction into N2 over reduced ceria-based catalyst","Wang, Y. (TU Delft ChemE/Catalysis Engineering); Makkee, M. (TU Delft ChemE/Catalysis Engineering)","","2018","Oxygen defects in reduced ceria are the catalytic sites for the NO reduction into N2 in the Toyota Di-Air DeNOx abatement technology. Traces of NO (several hundred ppm) have to compete with the excess amount of other oxidants, e.g., 5% CO2 and 5% O2, in an exhaust gas of a lean burn (diesel) engine. The reactivities of CO2 and NO over a reduced ceria and noble metal loaded reduced ceria have been investigated under ultra-high vacuum system in TAP and under atmosphere pressure in in-situ Raman and flow reactor set-up. The results showed that CO2 was a mild oxidant which was able to oxidise the oxygen defects, but hardly oxidised deposited carbon over both ceria and noble metal loaded ceria. NO was a stronger oxidant and more efficient in refilling the oxygen defects and able to convert the deposited carbon, which acted as buffer reductant to extend the NO reduction time interval. NO was selectively and completely converted into N2. The presence of excess CO2 hardly affected the NO reduction process into N2.","Ceria; CO activation; NO reduction; Noble metal; Oxygen defects","en","journal article","","","","","","Accepted Author Manuscript","","","","","ChemE/Catalysis Engineering","","",""
"uuid:490ae800-84b3-4ed6-a4bb-356f5446d61f","http://resolver.tudelft.nl/uuid:490ae800-84b3-4ed6-a4bb-356f5446d61f","Wavenumber-Domain Multiband Signal Fusion With Matrix-Pencil Approach for High-Resolution Imaging","Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Aubry, P.J. (TU Delft Microwave Sensing, Signals & Systems); Yarovoy, Alexander (TU Delft Microwave Sensing, Signals & Systems)","","2018","In this paper, a wavenumber-domain matrix-pencil-based multiband signal fusion approach was proposed for multiband microwave imaging. The approach proposed is based on the Born approximation of the field scattered from a target resulting in the fact that in a given scattering direction, the scattered field can be represented over the whole frequency band as a sum of the same number of contributions. Exploiting the measured multiband data and taking advantage of the parametric modeling for the signals in a radial direction, a unified signal model can be estimated for a large bandwidth in the wavenumber domain. It can be used to fuse the signals at different subbands by extrapolating the missing data in the frequency gaps between them or coherently integrating the overlaps between the adjacent subbands, thus synthesizing an equivalent wideband signal spectrum. Taking an inverse Fourier transform, the synthesized spectrum results in a focused image with improved resolution. Compared with the space-time domain fusion methods, the proposed approach is applicable for radar imaging with the signals collected by either collocated or noncollocated arrays in different frequency bands. Its effectiveness and accuracy are demonstrated through both numerical simulations and experimental imaging results.","Matrix-pencil approach (MPA); microwave imaging; multiband signal; signal fusion; wavenumber domain.","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","","","","Microwave Sensing, Signals & Systems","","",""
"uuid:a18674ca-abc2-4114-985b-26fa324249bb","http://resolver.tudelft.nl/uuid:a18674ca-abc2-4114-985b-26fa324249bb","Interface-Engineered Li7La3Zr2O12-Based Garnet Solid Electrolytes with Suppressed Li-Dendrite Formation and Enhanced Electrochemical Performance","Zhang, Zhaoshuai (Yanshan University); Zhang, Long (Yanshan University); Liu, Yanyan (Yanshan University); Wang, Hongqiang (Hebei University); Yu, C. (TU Delft RST/Storage of Electrochemical Energy); Zeng, Hong (China Iron & Steel Research Institute Group); Wang, L. (Yanshan University); Xu, B. (Yanshan University)","","2018","High grain-boundary resistance, Li-dendrite formation, and electrode/Li interfacial resistance are three major issues facing garnet-based solid electrolytes. Herein, interfacial architecture engineering by incorporating 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide (BMP-TFSI) ionic liquid into a garnet oxide is proposed. The “soft” continuous BMP-TFSI coating with no added Li salt generates a conducting network facilitating Li+ transport and thus changes the ion conduction mode from point contacts to face contacts. The compacted microstructure suppresses Li-dendrite growth and shows good interfacial compatibility and interfacial wettability toward Li metal. Along with a broad electrochemical window larger than 5.5 V and an Li+ transference number that practically reaches unity, LiNi0.8Co0.1Mn0.1O2/Li and LiFePO4/Li solid-state batteries with the hybrid solid electrolyte exhibit superior cycling stability and low polarization, comparable to those with commercial liquid electrolytes, and excellent rate capability that is better than those of Li-salt-based ionic-liquid electrolytes.","batteries; garnet; interfaces; ionic liquids; solid electrolytes","en","journal article","","","","","","Accepted Author Manuscript","","2019-09-07","","","RST/Storage of Electrochemical Energy","","",""
"uuid:adb60487-10de-4d0e-9ba7-ffcbb309b369","http://resolver.tudelft.nl/uuid:adb60487-10de-4d0e-9ba7-ffcbb309b369","A narrative perspective on institutional work in environmental governance – insights from a beach nourishment case study in Sweden","Bontje, L.E. (TU Delft Policy Analysis); Gomes, S.L. (TU Delft Policy Analysis); Wang, Zilin (Student TU Delft); Slinger, J (TU Delft Policy Analysis)","","2018","Institutional work offers a promising lens for understanding institutional change, focusing on the efforts of actors in creating, maintaining or disrupting institutions. In this paper, we explore the capacity of a narrative approach to provide insights on institutional work, using a case study from the coast of Sweden. We identify four narratives that compete in the policy discourse regarding erosion and beach nourishment in the coastal province of Scania. The narratives reveal that actors hold different beliefs concerning the magnitude of the erosion problem, the division of responsibilities and the suitability of sand nourishment as a coastal protection measure. The narrative competition is considered reflective of past institutional discussions and ongoing institutional work in coastal management in Scania, confirming that narratives are used as sense-making and meaning-giving devices in institutional discussions.","beach nourishment; case study; coastal management; institutional work; narratives","en","journal article","","","","","","","","","","","Policy Analysis","","",""
"uuid:f4210396-7abd-426a-85be-96dfd3794fc0","http://resolver.tudelft.nl/uuid:f4210396-7abd-426a-85be-96dfd3794fc0","Submicroscopic framework to model mixed highway traffic","Mullakkal-Babu, F.A. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning); Happee, R. (TU Delft Intelligent Vehicles)","Ciuffo, B (editor); Alonso Raposo, M (editor); Mourtzouchou, A (editor); Belov, A (editor); Makridis, M (editor); Mattas, K (editor); Mogno, C (editor)","2018","","","en","conference paper","Publications Office of the European Union","","","","","","","","","","Transport and Planning","","",""
"uuid:724d3e5d-a5ba-43c0-93a2-0f019c7e4b89","http://resolver.tudelft.nl/uuid:724d3e5d-a5ba-43c0-93a2-0f019c7e4b89","Optimization modeling of regional energy systems considering coordination mechanisms","Wang, N. (TU Delft Energie and Industrie); Heijnen, P.W. (TU Delft Energie and Industrie); Verzijlbergh, R.A. (TU Delft Energie and Industrie); Kunneke, R.W. (TU Delft Economics of Technology and Innovation); Herder, P.M. (TU Delft Energy Technology; TU Delft Energie and Industrie)","","2018","Dutch regional municipalities increasingly take an active role in the transition to more sustainable and autonomous energy supply systems, using local energy sources like wind, solar and biomass. The ambition, on the one hand, concerns how an optimal local energy supply system can be designed such that local energy targets can be realized with minimum dependence on the national energy grids. On the other hand, it is of importance to consider the coordination mechanisms between actors such as municipalities, local communities and grid operators, since they will influence the technical configuration of the system. In the literature about renewables-based regional energy systems, the technical optimizations are done mostly from a central planner point of view. Therefore, there lacks a study on the optimization models for regional renewable energy planning that has a comprehensive view on coordination mechanisms and their influence on the system performance. The objective of this work is to enhance the formulation of for self-sufficient regional energy systems by taking coordination mechanisms into account, in order to understand their influences on the system performance. In this paper, a toy model for making optimal long-term investment decisions in electricity generation and transmission will be presented. Two coordination mechanisms, namely one with a central planner, and the other one with a regional market, are considered. In addition, the different modeling approaches for rural and urban energy systems will be discussed. Initial results show that the coordination with a central planner has the least system cost. In the market-based coordination, it is recognized that the degree of shared information and of market participation influences the problem formulation. This results in the cost differences for different coordination mechanisms and for different actors, and thus gives policy implications in the choice of coordination mechanisms and in cost allocation.","Renewable energy sources; regional energy system modeling; optimization methods; coordination mechanisms","en","abstract","","","","","","","","","","","Energie and Industrie","","",""
"uuid:1436e9aa-8f8f-4ba4-b5b6-cec50d572f9d","http://resolver.tudelft.nl/uuid:1436e9aa-8f8f-4ba4-b5b6-cec50d572f9d","SimEx 2018 - Digital Exercise Environment","Meesters, Kenny (TU Delft Policy Analysis); Wang, Y. (TU Delft Management Support)","","2018","During SimEx2018 the large-scale field exercise was augmented with a digital environment. This digital environment consists of the digital presence of role-players on social media, the use of modern web technologies and the involvement of the Digital humanitarian Network (DHN). In SimEx2018 the DHN, specifically the Standby Task Force (SBTF) was activated and collaborated closely with UNDAC team. The value of DHN involvement was well recognized and proved to contribute to the response operations during the exercise. This report highlights the setup of the digital environment of SimEx, the activities executed prior and during the exercise, the management of SimEx digital environment and the lessons learned / reflections for future exercise and DHN development.","","en","report","","","","","","","","","","","Policy Analysis","","",""
"uuid:1d57be72-71f7-47bd-959b-94c5085b69c8","http://resolver.tudelft.nl/uuid:1d57be72-71f7-47bd-959b-94c5085b69c8","A nano-fibrous platform of copolymer patterned surfaces for controlled cell alignment","Zhang, K. (TU Delft ChemE/Advanced Soft Matter); Gil Arranja, A. (TU Delft RST/Applied Radiation & Isotopes; TU Delft ChemE/Advanced Soft Matter; University Medical Center Utrecht); Chen, Hongyu (Virginia Tech); Mytnyk, S. (TU Delft ChemE/Product and Process Engineering); Wang, Y. (TU Delft ChemE/Advanced Soft Matter); Oldenhof, S. (TU Delft ChemE/Advanced Soft Matter; Netherlands Forensic Institute - NFI); van Esch, J.H. (TU Delft ChemE/Advanced Soft Matter); Mendes, E. (TU Delft ChemE/Advanced Soft Matter)","","2018","The last decade has witnessed great progress in understanding and manipulating self-assembly of block copolymers in solution. A wide variety of micellar structures can be created and many promising applications in bioscience have been reported. In particular, nano-fibrous micelles provide a great platform to mimic the filamentous structure of native extracellular matrix (ECM). However, the evaluation of this kind of filomicellar system with potential use in tissue engineering is virtually unexplored. The question behind it, such as if the block copolymer nano-fibrous micelles can regulate cellular response, has lingered for many years because of the difficulties in preparation and 3D manipulation of these tiny objects. Here, by using a combination approach of self-assembly of block copolymers and soft lithography, we establish a novel and unique nano-fibrous 2D platform of organized micelles and demonstrate that patterned micelles enable control over the cellular alignment behavior. The area density and orientation of fibrous micelles determine the alignment degree and directionality of cells, respectively. Furthermore, when cells were cultured on multi-directionally aligned micelles, a competitive response was observed. Due to the virtually infinite possibilities of functionalization of the micelle corona, our work opens a new route to further mimic the native fibrous networks with artificial micelles containing various functionalities.","","en","journal article","","","","","","","","","","","ChemE/Advanced Soft Matter","","",""
"uuid:4b86cd28-c0a6-444e-a0f8-2d6a760ed417","http://resolver.tudelft.nl/uuid:4b86cd28-c0a6-444e-a0f8-2d6a760ed417","Absorption refrigeration cycles with ammonia-ionic liquid working pairs studied by molecular simulation","Becker, T. (TU Delft Engineering Thermodynamics); Wang, M. (TU Delft Engineering Thermodynamics); Kabra, Abhishek (Student TU Delft); Jamali, S.H. (TU Delft Engineering Thermodynamics); Ramdin, M. (TU Delft Engineering Thermodynamics); Dubbeldam, D. (TU Delft Engineering Thermodynamics; Universiteit van Amsterdam); Infante Ferreira, C.A. (TU Delft Engineering Thermodynamics); Vlugt, T.J.H. (TU Delft Engineering Thermodynamics)","","2018","For absorption refrigeration, it has been shown that ionic liquids have the potential to replace conventional working pairs. Due to the huge number of possibilities, conducting lab experiments to find the optimal ionic liquid is infeasible. Here, we provide a proof-of-principle study of an alternative computational approach. The required thermodynamic properties, i.e., solubility, heat capacity, and heat of absorption, are determined via molecular simulations. These properties are used in a model of the absorption refrigeration cycle to estimate the circulation ratio and the coefficient of performance. We selected two ionic liquids as absorbents: [emim][Tf2N], and [emim][SCN]. As refrigerant NH3 was chosen due to its favorable operating range. The results are compared to the traditional approach in which parameters of a thermodynamic model are fitted to reproduce experimental data. The work shows that simulations can be used to predict the required thermodynamic properties to estimate the performance of absorption refrigeration cycles. However, high-quality force fields are required to accurately predict the cycle performance.","","en","journal article","","","","","","","","","","","Engineering Thermodynamics","","",""
"uuid:9ecbacfc-1675-4e72-8d59-9049668b016f","http://resolver.tudelft.nl/uuid:9ecbacfc-1675-4e72-8d59-9049668b016f","Cooperative Economic Scheduling for Multiple Energy Hubs: A Bargaining Game Theoretic Perspective","Fan, Songli (Shanghai Jiao Tong University); Li, Zhengshuo (Tsinghua University); Wang, Jianhui (Southern Methodist University); Piao, L. (TU Delft Algorithmics); Ai, Qian (Shanghai Jiao Tong University)","","2018","Under the background of global energy conservation, the energy hub (EH)-based integrated energy system is becoming the transition direction of future energy structure. In this paper, we study the cooperative economic scheduling problem for multiple neighboring integrated energy systems on the basis of EH. Different with the traditional non-cooperative mode where each EH operates individually, these EHs constitute a cooperative community and can share energy among them. Considering the autonomy and selfinterest of different EHs, the coordinated management problem is modeled as a bargaining cooperative game, where involved EHs will bargain with each other about the exchanged energy and the associated payments. The bargaining solution can achieve a fair and Pareto-optimal balance among the objective functions of different EHs. A distributed optimization is applied to find the bargaining solution of the cooperative system, to guarantee the autonomous scheduling and information privacy of EHs. Numerical studies demonstrate the effectiveness of the bargaining-based cooperative economic scheduling framework, and also show the improvement of benefits of the community system.","Cooperative game; distributed approach; energy hub; energy trading; multiple energy system; Nash bargaining","en","journal article","","","","","","","","","","","Algorithmics","","",""
"uuid:5155aa7a-2b76-4599-b4f5-8d6a3c859e9f","http://resolver.tudelft.nl/uuid:5155aa7a-2b76-4599-b4f5-8d6a3c859e9f","Computational fluid dynamics simulation of an industrial P. chrysogenum fermentation with a coupled 9-pool metabolic model: Towards rational scale-down and design optimization","Haringa, C. (TU Delft ChemE/Transport Phenomena); Tang, W. (TU Delft OLD BT/Cell Systems Engineering); Wang, G. (TU Delft OLD BT/Cell Systems Engineering); Deshmukh, A.T. (TU Delft OLD BT/Cell Systems Engineering); van Winden, Wouter A. (DSM); Chu, Ju (East China University of Technology); van Gulik, W.M. (TU Delft OLD BT/Cell Systems Engineering); Heijnen, J.J. (TU Delft OLD BT/Cell Systems Engineering); Mudde, R.F. (TU Delft ChemE/Transport Phenomena); Noorman, H.J. (TU Delft BT/Bioprocess Engineering)","","2018","We assess the effect of substrate heterogeneity on the metabolic response of P. chrysogenum in industrial bioreactors via the coupling of a 9-pool metabolic model with Euler-Lagrange CFD simulations. In this work, we outline how this coupled hydrodynamic-metabolic modeling can be utilized in 5 steps. (1) A model response study with a fixed spatial extra-cellular glucose concentration gradient, which reveals a drop in penicillin production rate qp of 18–50% for the simulated reactor, depending on model setup. (2) CFD-based scale-down design, where we design a 1-vessel scale down simulator based on the organism lifelines. (3) Scale-down verification, numerically comparing the model response in the proposed scale-down simulator with large-scale CFD response. (4) Reactor design optimization, reducing the drop in penicillin production by a change of feed location. (5) Long-term fed-batch simulation, where we verify model predictions against experimental data, and discuss population heterogeneity. Overall, these steps present a coupled hydrodynamic-metabolic approach towards bioreactor evaluation, scale-down and optimization.","CFD; Euler-Langrange; Industrial; Metabolic model; Scale-down","en","journal article","","","","","","","","","","","ChemE/Transport Phenomena","","",""
"uuid:6eb5f815-3f5c-4936-aab3-d8cc5c36e427","http://resolver.tudelft.nl/uuid:6eb5f815-3f5c-4936-aab3-d8cc5c36e427","Throbbing between two lives: Resource pooling in service supply chains","van Oorschot, Kim (BI Norwegian Business School); Wang, Y. (TU Delft Research Data and Software; TU Delft Management Support); Akkermans, Henk (Tilburg School of Economics and Management)","Bui, Tung X. (editor)","2018","Resource pooling is known to benefit performance through reduced congestion, but primarily in settings with homogenous demand. In settings where demand is heterogeneous, pooling can be counter effective. The effects of pooling of staff when demand is heterogeneous and dependent are not known. We present a simulation model based on a service supply chain that delivers Interactive TV to customers. Customers expect high performance in terms of innovativeness and reliability. Based on the results of simulation analysis, we find that when target innovativeness of the service is increased, pooling outperforms not pooling, but the delays that are involved with pooling will make the system and hence its performance unstable. Stable and high performance can be realized through “unbalanced” hiring. This means that a target performance increase in the upstream stage of the chain (innovation), is accompanied by hiring staff in the downstream stages of the chain (QA and operation).","","en","conference paper","IEEE","","","","","","","","","","Research Data and Software","","",""
"uuid:bb1d09e5-9a11-4db2-9d37-2338778e232e","http://resolver.tudelft.nl/uuid:bb1d09e5-9a11-4db2-9d37-2338778e232e","Reconstructing phylogeny by aligning multiple metabolic pathways using functional module mapping","Huang, Yiran (Guangxi University; South China University of Technology; Guangxi Teachers Education University); Zhong, Cheng (Guangxi University); Lin, H.X. (TU Delft Mathematical Physics); Wang, Jianyi (Guangxi University); Peng, Yuzhong (Guangxi Teachers Education University)","","2018","Comparison of metabolic pathways provides a systematic way for understanding the evolutionary and phylogenetic relationships in systems biology. Although a number of phylogenetic methods have been developed, few efforts have been made to provide a unified phylogenetic framework that sufficiently reflects the metabolic features of organisms. In this paper, we propose a phylogenetic framework that characterizes the metabolic features of organisms by aligning multiple metabolic pathways using functional module mapping. Our method transforms the alignment of multiple metabolic pathways into constructing the union graph of pathways, builds mappings between functional modules of pathways in the union graph, and infers phylogenetic relationships among organisms based on module mappings. Experimental results show that the use of functional module mapping enables us to correctly categorize organisms into main categories with specific metabolic characteristics. Traditional genome-based phylogenetic methods can reconstruct phylogenetic relationships, whereas our method can offer in-depth metabolic analysis for phylogenetic reconstruction, which can add insights into traditional phyletic reconstruction. The results also demonstrate that our phylogenetic trees are closer to the classic classifications in comparison to existing classification methods using metabolic pathway data.","Functional module mapping; Metabolic pathway alignment; Phylogenetic tree; Union graph","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:6a79b9f7-ab20-4c1b-8554-687b7de569dd","http://resolver.tudelft.nl/uuid:6a79b9f7-ab20-4c1b-8554-687b7de569dd","Novel light-guide-PMT geometries to reduce dead edges of a scintillation camera","Wang, B. (TU Delft RST/Biomedical Imaging); Kreuger, R. (TU Delft RST/Biomedical Imaging); Beekman, F.J. (TU Delft RST/Biomedical Imaging; MILabs B.V.); Goorden, M.C. (TU Delft RST/Biomedical Imaging)","","2018","Anger cameras based on monolithic NaI scintillators read out by an array of PMTs are predominant in planar gamma imaging and SPECT. However, position estimation of gamma interactions is usually severely degraded near the edges of the scintillator which can be extremely undesirable for applications like breast imaging. Here we propose a relatively cost-effective solution based on the use of scintillators with absorptive edges with an unconventional light-guide-PMT layout employing a maximum likelihood positioning algorithm. The basic design on which we aim to improve consists of a monolithic NaI(Tl) scintillator read out by 3 × 5 square PMTs (conventional layout, CL) that could be suitable for molecular breast imaging. To better detect gamma interactions near the crystal's critical edge, we tried different set-ups: we replaced the 5 large PMTs near the edge by 11 smaller PMTs (small-sensor layout, SSL); we emulated rectangular PMTs along the critical edge by inserting a row of 5 rectangular light-guides that direct the light toward square PMTs placed behind (shifted layout, SL); we inserted rectangular light-guides alternatingly, such that the PMTs are in an interlocking pattern (alternating shifted layout, ASL). The performance of our designs was tested with Monte Carlo simulations. Results showed that SSL, SL, and ASL gave better spatial resolution near the critical edge than CL (3.4, 3.6, and 4.1 mm near the edge compared with 5.3 mm for CL), and thus resulted in a larger usable detector area. To conclude, for applications where small dead edges are crucial, our designs may be cost-effective solutions.","Dead edge; Gamma-ray detectors; Maximum likelihood estimation; Photomultiplier tube","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-10-10","","","RST/Biomedical Imaging","","",""
"uuid:dcc76b44-6b02-4c20-9cde-8895edc8aa48","http://resolver.tudelft.nl/uuid:dcc76b44-6b02-4c20-9cde-8895edc8aa48","An Extended Chemical Plant Environmental Protection Game on Addressing Uncertainties of Human Adversaries","Zhu, Zhengqiu (National University of Defense Technology); Chen, B. (National University of Defense Technology); Qiu, S. (TU Delft Web Information Systems; National University of Defense Technology); Wang, Rongxiao (National University of Defense Technology); Chen, Feiran (National University of Defense Technology); Wang, Yiping (Naval 902 Factory); Qiu, Xiaogang (National University of Defense Technology)","","2018","Chemical production activities in industrial districts pose great threats to the surroundingatmospheric environment and human health. Therefore, developing appropriate and intelligentpollution controlling strategies for the management team to monitor chemical production processesis significantly essential in a chemical industrial district. The literature shows that playing a chemicalplant environmental protection (CPEP) game can force the chemical plants to be more compliantwith environmental protection authorities and reduce the potential risks of hazardous gas dispersionaccidents. However, results of the current literature strictly rely on several perfect assumptions whichrarely hold in real-world domains, especially when dealing with human adversaries. To addressbounded rationality and limited observability in human cognition, the CPEP game is extended togenerate robust schedules of inspection resources for inspection agencies. The present paper isinnovative on the following contributions: (i) The CPEP model is extended by taking observationfrequency and observation cost of adversaries into account, and thus better reflects the industrialreality; (ii) Uncertainties such as attackers with bounded rationality, attackers with limited observationand incomplete information (i.e., the attacker’s parameters) are integrated into the extended CPEPmodel; (iii) Learning curve theory is employed to determine the attacker’s observability in the gamesolver. Results in the case study imply that this work improves the decision-making process forenvironmental protection authorities in practical fields by bringing more rewards to the inspectionagencies and by acquiring more compliance from chemical plants.","Bounded rationality; Chemical plant environmental protection game; Human cognition; Learning curves; Limited observation","en","journal article","","","","","","","","","","","Web Information Systems","","",""
"uuid:a7a44200-864d-4d88-bb04-0a4224f9271e","http://resolver.tudelft.nl/uuid:a7a44200-864d-4d88-bb04-0a4224f9271e","Hazardous Source Estimation Using an Artificial Neural Network, Particle Swarm Optimization and a Simulated Annealing Algorithm","Wang, Rongxiao (National University of Defense Technology); Chen, B. (National University of Defense Technology); Qiu, S. (TU Delft Web Information Systems; National University of Defense Technology); Ma, Liang (National University of Defense Technology); Zhu, Zhengqiu (National University of Defense Technology); Wang, Yiping (Naval 902 Factory); Qiu, Xiaogang (National University of Defense Technology)","","2018","Locating and quantifying the emission source plays a significant role in the emergency management of hazardous gas leak accidents. Due to the lack of a desirable atmospheric dispersion model, current source estimation algorithms cannot meet the requirements of both accuracy and efficiency. In addition, the original optimization algorithm can hardly estimate the source accurately, because of the difficulty in balancing the local searching with the global searching. To deal with these problems, in this paper, a source estimation method is proposed using an artificial neural network (ANN), particle swarm optimization (PSO), and a simulated annealing algorithm (SA). This novel method uses numerous pre-determined scenarios to train the ANN, so that the ANN can predict dispersion accurately and efficiently. Further, the SA is applied in the PSO to improve the global searching ability. The proposed method is firstly tested by a numerical case study based on process hazard analysis software (PHAST), with analysis of receptor configuration and measurement noise. Then, the Indianapolis field case study is applied to verify the effectiveness of the proposed method in practice. Results demonstrate that the hybrid SAPSO algorithm coupled with the ANN prediction model has better performances than conventional methods in both numerical and field cases.","Artificial neural network; Atmospheric dispersion model; Particle swarm optimization; Simulated annealing algorithm; Source estimation","en","journal article","","","","","","","","","","","Web Information Systems","","",""
"uuid:0d475332-5377-45d3-8dc6-212ff990cd58","http://resolver.tudelft.nl/uuid:0d475332-5377-45d3-8dc6-212ff990cd58","On solving wave equations on fixed bounded intervals involving Robin boundary conditions with time-dependent coefficients","van Horssen, W.T. (TU Delft Mathematical Physics); Wang, Y. (TU Delft Mathematical Physics; China University of Mining and Technology); Cao, G. (China University of Mining and Technology)","","2018","In this paper, it is shown how characteristic coordinates, or equivalently how the well-known formula of d'Alembert, can be used to solve initial-boundary value problems for wave equations on fixed, bounded intervals involving Robin type of boundary conditions with time-dependent coefficients. A Robin boundary condition is a condition that specifies a linear combination of the dependent variable and its first order space-derivative on a boundary of the interval. Analytical methods, such as the method of separation of variables (SOV) or the Laplace transform method, are not applicable to those types of problems. The obtained analytical results by applying the proposed method, are in complete agreement with those obtained by using the numerical, finite difference method. For problems with time-independent coefficients in the Robin boundary condition(s), the results of the proposed method also completely agree with those as for instance obtained by the method of separation of variables, or by the finite difference method.","Characteristic coordinates; Formula of d'Alembert; Robin boundary condition; Time-dependent coefficient; Wave equation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-02-25","","","Mathematical Physics","","",""
"uuid:3d57c515-a297-474b-a91d-73a1b7583d17","http://resolver.tudelft.nl/uuid:3d57c515-a297-474b-a91d-73a1b7583d17","Dynamic optimization of ship energy efficiency considering time-varying environmental factors","Wang, K. (TU Delft Transport Engineering and Logistics; Wuhan University of Technology); Yan, Xinping (Wuhan University of Technology; MOST); Yuan, Yupeng (Wuhan University of Technology; University of Cambridge); Jiang, X. (TU Delft Transport Engineering and Logistics); Lin, X. (TU Delft Transport Engineering and Logistics); Negenborn, R.R. (TU Delft Transport Engineering and Logistics)","","2018","Nowadays, optimization of ship energy efficiency attracts increasing attention in order to meet the requirement for energy conservation and emission reduction. Ship operation energy efficiency is significantly influenced by environmental factors such as wind speed and direction, water speed and depth. Owing to inherent time-variety and uncertainty associated with these various factors, it is very difficult to determine optimal sailing speeds accurately for different legs of the whole route using traditional static optimization methods, especially when the weather conditions change frequently over the length of a ship route. Therefore, in this paper, a novel dynamic optimization method adopting the model predictive control (MPC) strategy is proposed to optimize ship energy efficiency accounting for these time-varying environmental factors. Firstly, the dynamic optimization model of ship energy efficiency considering time-varying environmental factors and the nonlinear system model of ship energy efficiency are established. On this basis, the control algorithm and controller for the dynamic optimization of ship energy efficiency (DOSEE) are designed. Finally, a case study is carried out to demonstrate the validity of this optimization method. The results indicate that the optimal sailing speeds at different time steps could be determined through the dynamic optimization method. This method can improve ship energy efficiency and reduce CO2 emissions effectively.","Dynamic optimization; Energy conservation and emission reduction; Model predictive control; Ship energy efficiency; Speed optimization","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-11-01","","","Transport Engineering and Logistics","","",""
"uuid:2c8d7d7d-8d86-47d3-9c9c-77f79b0ffe24","http://resolver.tudelft.nl/uuid:2c8d7d7d-8d86-47d3-9c9c-77f79b0ffe24","Dynamic simulation of a multi-cable driven parallel suspension platform with slack cables","Wang, Y. (TU Delft Mathematical Physics; China University of Mining and Technology); Cao, G. (China University of Mining and Technology); van Horssen, W.T. (TU Delft Mathematical Physics)","","2018","In this paper, a modelling method and an accurate numerical procedure are presented to simulate the dynamical responses of a multi-cable driven parallel suspension platform system. For such systems, the cables might become slack due to external excitations and due to the fact that cables can become tensionless when been pushed in longitudinal direction. In lateral and torsional directions, the constraint forces between the cables and platform can be positive as well as negative. This paper will deal with the non-smooth cable vibrations (in longitudinal, lateral and torsional directions) by taking into account the slackness of the cables. Firstly, the Lagrange equation with constraints is used to derive the equations of motion of the multi-cable suspension platform. Then, by expressing the equations of motion and constraint equations at velocity level, a non-smooth algorithm is used to numerically solve the equations. Finally, the numerical results are compared with an ADAMS simulation, and the two results agree well with each other. Moreover, the results in this paper significantly improve the numerical results used in the analysis of the dynamics for multi-cable systems which usually neglect the lateral properties of the cables.","Multi-cable driven manipulators; Non-smooth cable vibrations; Non-smooth generalized-α scheme; Slack cable","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-03-31","","","Mathematical Physics","","",""
"uuid:98661794-6d17-4a32-bc85-784838e3894f","http://resolver.tudelft.nl/uuid:98661794-6d17-4a32-bc85-784838e3894f","Efficient Implementation of GPR Data Inversion in Case of Spatially Varying Antenna Polarizations","Wang, J. (TU Delft Microwave Sensing, Signals & Systems); Aubry, P.J. (TU Delft Microwave Sensing, Signals & Systems); Yarovoy, Alexander (TU Delft Microwave Sensing, Signals & Systems)","","2018","Ground penetrating radar imaging from the data acquired with arbitrarily oriented dipole-like antennas is considered. To take into account variations of antenna orientations resulting in spatial rotation of antenna radiation patterns and polarizations of transmitted fields, the full-wave method that accounts for the near-, intermediate-, and far-field contributions to the radiation patterns is applied for image reconstruction, which is formulated as a linear inversion problem. Two approaches, namely, an interpolation-based method and a nonuniform fast Fourier transform-based method, are suggested to efficiently implement the full-wave method by computing exact Green's functions. The effectiveness and accuracy of the method proposed have been verified via both numerical simulations and experimental measurements, and significant improvement of the reconstructed image quality compared with the traditional scalar-wave-based migration algorithms is demonstrated. The results can be directly utilized by forward-looking microwave imaging sensors such as installed at tunnel boring machine or can be used for the observation matrix computation in regularization-based inversion algorithms.","Antenna radiation patterns; Dipole antennas; Green's function (GF); Ground penetrating radar; ground penetrating radar (GPR); Microwave antenna arrays; microwave imaging; nonuniform fast Fourier transform (NUFFT); Radar antennas; radiation pattern; rotated array.","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-12-03","","","Microwave Sensing, Signals & Systems","","",""
"uuid:86266ed1-b6db-4f87-8f6f-e89fdb90df7b","http://resolver.tudelft.nl/uuid:86266ed1-b6db-4f87-8f6f-e89fdb90df7b","Improvement of mechanical performance of bioresorbable magnesium alloy coronary artery stents through stent pattern redesign","Wang, Qian (Tsinghua University); Fang, Gang (Tsinghua University); Zhao, Ying Hong (Shanghai Bio-heart Biological Technology Co. Ltd.); Zhou, J. (TU Delft Biomaterials & Tissue Biomechanics)","","2018","Optimized stent pattern design can effectively enhance the mechanical performance of magnesium alloy stents by adjusting strain distribution and evolution during stent deformation, thereby overcoming the limitations imposed by the intrinsic mechanical properties of magnesium alloys. In the present study, a new stent design pattern for magnesium alloys was proposed and compared to two existing stent design patterns. Measures of the mechanical performance of these three stents, including crimping and expanding deformability, radial scaffolding capacity, radial recoil and bending flexibility, were determined. Three-dimensional finite element (FE) models were built to predict the mechanical performance of the stents with the three design patterns and to assist in understanding the experimental results. The results showed that, overall, the stent with the new design pattern was superior to the stents based on the existing designs, though the expanding capacity of the newly designed stent still needed to be improved.","Bioresorbable stent; Deformation behavior; Finite element analysis; Magnesium; Mechanical property","en","journal article","","","","","","","","","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:1058f0be-3bea-48e8-9317-069bf943f83d","http://resolver.tudelft.nl/uuid:1058f0be-3bea-48e8-9317-069bf943f83d","Parity transitions in the superconducting ground state of hybrid InSb-Al Coulomb islands","Shen, J. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); Heedt, S. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); Borsoi, F. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); van Heck, B. (TU Delft QRD/Kouwenhoven Lab; University of California; Microsoft Quantum Lab Delft); Gazibegovic, S. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; Eindhoven University of Technology); op het Veld, R.L.M. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; Eindhoven University of Technology); Car, D. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; Eindhoven University of Technology); Ramakers, S.J.J. (TU Delft Applied Sciences; Kavli institute of nanoscience Delft); Wang, Guanzhong (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); Xu, D. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); Bouman, D. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft); Geresdi, A. (TU Delft QRD/Geresdi Lab; Kavli institute of nanoscience Delft); Bakkers, E.P.A.M. (TU Delft QN/Bakkers Lab; Kavli institute of nanoscience Delft; Eindhoven University of Technology); Kouwenhoven, Leo P. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; Microsoft Quantum Lab Delft)","","2018","The number of electrons in small metallic or semiconducting islands is quantised. When tunnelling is enabled via opaque barriers this number can change by an integer. In superconductors the addition is in units of two electron charges (2e), reflecting that the Cooper pair condensate must have an even parity. This ground state (GS) is foundational for all superconducting qubit devices. Here, we study a hybrid superconducting-semiconducting island and find three typical GS evolutions in a parallel magnetic field: a robust 2e-periodic even-parity GS, a transition to a 2e-periodic odd-parity GS, and a transition from a 2e- to a 1e-periodic GS. The 2e-periodic odd-parity GS persistent in gate-voltage occurs when a spin-resolved subgap state crosses zero energy. For our 1e-periodic GSs we explicitly show the origin being a single zero-energy state gapped from the continuum, i.e., compatible with an Andreev bound states stabilized at zero energy or the presence of Majorana zero modes.","","en","journal article","","","","","","","","","Applied Sciences","","QRD/Kouwenhoven Lab","","",""
"uuid:dcac7bfe-3c14-40e0-8ba8-d7d0ac9e5c6b","http://resolver.tudelft.nl/uuid:dcac7bfe-3c14-40e0-8ba8-d7d0ac9e5c6b","Spin-Orbit Interaction and Induced Superconductivity in a One-Dimensional Hole Gas","de Vries, F.K. (TU Delft QRD/Goswami Lab; TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Shen, J. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Skolasinski, R.J. (TU Delft Quantum Computing Division; TU Delft QRD/Wimmer Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Nowak, M.P. (AGH University of Science and Technology); Varjas, D. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, L. (TU Delft QN/Akhmerov Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wimmer, M.T. (TU Delft QRD/Wimmer Group; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Zwanenburg, F.A. (University of Twente); Li, A. (Eindhoven University of Technology); Kölling, S. (Eindhoven University of Technology); Verheijen, M.P.A.M. (Eindhoven University of Technology; Philips Research); Bakkers, E.P.A.M. (Eindhoven University of Technology); Kouwenhoven, Leo P. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; Microsoft Quantum Lab Delft)","","2018","Low dimensional semiconducting structures with strong spin-orbit interaction (SOI) and induced superconductivity attracted great interest in the search for topological superconductors. Both the strong SOI and hard superconducting gap are directly related to the topological protection of the predicted Majorana bound states. Here we explore the one-dimensional hole gas in germanium silicon (Ge-Si) core-shell nanowires (NWs) as a new material candidate for creating a topological superconductor. Fitting multiple Andreev reflection measurements shows that the NW has two transport channels only, underlining its one-dimensionality. Furthermore, we find anisotropy of the Landé g-factor that, combined with band structure calculations, provides us qualitative evidence for the direct Rashba SOI and a strong orbital effect of the magnetic field. Finally, a hard superconducting gap is found in the tunneling regime and the open regime, where we use the Kondo peak as a new tool to gauge the quality of the superconducting gap.","g-factor anisotropy; hole transport; Josephson junction; multiple Andreev reflection; nanowires; Spin-orbit interaction","en","journal article","","","","","","","","","","Quantum Computing Division","QRD/Goswami Lab","","",""
"uuid:260e1e55-b567-4bda-96de-c8b3b1a81561","http://resolver.tudelft.nl/uuid:260e1e55-b567-4bda-96de-c8b3b1a81561","Fundamental understanding of the Di-Air system (an alternative NOx abatement technology). I: The difference in reductant pre-treatment of ceria","Wang, Y. (TU Delft ChemE/Catalysis Engineering); Makkee, M. (TU Delft ChemE/Catalysis Engineering)","","2018","Toyota's Di-Air DeNOx system is a promising DeNOx system to meet NOx emission requirement during the real driving, yet, a fundamental understanding largely lacks, e.g. the benefit of fast frequency fuel injection. Ceria is the main ingredient in Di-Air catalyst composition. Hence, we investigated the reduction of ceria by reductants, e.g. CO, H2, and hydrocarbons (C3H6 and C3H8), with Temporal Analysis of Product (TAP) technique. The results show that the reduction by CO yielded a faster catalyst reduction rate than that of H2. However, they reached the same final degree of ceria reduction. Hydrocarbons generated almost three times deeper degree of ceria reduction than that with CO and H2. In addition, hydrocarbons resulted in carbonaceous deposits on the ceria surface. The total amount of converted NO over the C3H6 reduced sample is around ten times more than that of CO. The deeper degree of reduction and the deposition of carbon by hydrocarbon explain why hydrocarbons are the most powerful reductants in Toyota's Di-Air NOx abatement system.","Ceria; CO oxidation; Di-Air; Hydrocarbon oxidation/cracking; TAP","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:0c630414-d76f-466c-a2de-3de526766ea7","http://resolver.tudelft.nl/uuid:0c630414-d76f-466c-a2de-3de526766ea7","Enabling nanoscale flexoelectricity at extreme temperature by tuning cation diffusion","Molina-Luna, Leopoldo (Technische Universität Darmstadt); Wang, Shuai (Technische Universität Darmstadt); Pivak, Yevheniy (DENSsolutions); Zintler, Alexander (Technische Universität Darmstadt); Perez Garza, H.H. (DENSsolutions); Spruit, R.G. (DENSsolutions); Xu, Q. (TU Delft QN/Zandbergen Lab; DENSsolutions; Kavli institute of nanoscience Delft); Yi, Min (Technische Universität Darmstadt); Xu, Bai Xiang (Technische Universität Darmstadt); Acosta, Matias (Technische Universität Darmstadt)","","2018","Any dielectric material under a strain gradient presents flexoelectricity. Here, we synthesized 0.75 sodium bismuth titanate −0.25 strontium titanate (NBT-25ST) core–shell nanoparticles via a solid-state chemical reaction directly inside a transmission electron microscope (TEM) and observed domain-like nanoregions (DLNRs) up to an extreme temperature of 800 °C. We attribute this abnormal phenomenon to a chemically induced lattice strain gradient present in the core–shell nanoparticle. The strain gradient was generated by controlling the diffusion of strontium cations. By combining electrical biasing and temperature-dependent in situ TEM with phase field simulations, we analyzed the resulting strain gradient and local polarization distribution within a single nanoparticle. The analysis confirms that a local symmetry breaking, occurring due to a strain gradient (i.e. flexoelectricity), accounts for switchable polarization beyond the conventional temperature range of existing polar materials. We demonstrate that polar nanomaterials can be obtained through flexoelectricity at extreme temperature by tuning the cation diffusion.","","en","journal article","","","","","","","","","","","QN/Zandbergen Lab","","",""
"uuid:63b115c9-6ec1-40d7-8bb3-33dcc6d4cb10","http://resolver.tudelft.nl/uuid:63b115c9-6ec1-40d7-8bb3-33dcc6d4cb10","Underwater Source Localization Using TDOA and FDOA Measurements with Unknown Propagation Speed and Sensor Parameter Errors","Zhang, Bingbing (National University of Defense Technology); Hu, Y. (TU Delft Signal Processing Systems); Wang, Hongying (National University of Defense Technology); Zhuang, Zhaowen (National University of Defense Technology)","","2018","Underwater source localization problems are complicated and challenging: a) the sound propagation speed is often unknown and the unpredictable ocean current might lead to the uncertainties of sensor parameters (i.e. position and velocity); b) the underwater acoustic signal travels much slower than the radio one in terrestrial environments, thus resulting into a significantly severe Doppler effect; c) energy-efficient techniques are urgently required and hence in favour of the design with a low computational complexity. Considering these issues, we propose a simple and efficient underwater source localization approach based on time difference of arrival (TDOA) and frequency difference of arrival (FDOA) measurements, which copes with unknown propagation speed and sensor parameter errors. The proposed method mitigates the impact of the Doppler effect for accurately inferring the source parameters (i.e. position and velocity). The Cramér-Rao lower bounds (CRLBs) for this kind of localization are derived and, moreover, the analytical study shows that our method can yield the performance that is very close to the CRLB, particularly under small noise. The numerical results not only confirm the above conclusions but also show that our method outperforms other competing approaches.","algebraic solution; Covariance matrices; Current measurement; Doppler effect; frequency difference of arrival (FDOA); Measurement uncertainty; Oceans; Sea measurements; sensor node uncertainty; sound propagation speed uncertainty; time difference of arrival (TDOA); Uncertainty; Underwater localization","en","journal article","","","","","","","","","","","Signal Processing Systems","","",""
"uuid:04d2de5b-ab39-44ba-be2b-562fa0a26075","http://resolver.tudelft.nl/uuid:04d2de5b-ab39-44ba-be2b-562fa0a26075","Benzimidazole linked polymers (BILPs) in mixed-matrix membranes: Influence of filler porosity on the CO2/N2 separation performance","Shan, M. (TU Delft ChemE/Catalysis Engineering; TU Delft ChemE/Transport Phenomena); Seoane, Beatriz (Debye Institute); Pustovarenko, Alexey (King Abdullah University of Science and Technology); Wang, X. (TU Delft ChemE/Catalysis Engineering); Liu, X. (TU Delft ChemE/Catalysis Engineering); Yarulina, I. (King Abdullah University of Science and Technology); Abou-Hamad, Edy (King Abdullah University of Science and Technology); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering); Gascon, Jorge (TU Delft ChemE/Catalysis Engineering; King Abdullah University of Science and Technology)","","2018","The performance of mixed-matrix membranes (MMMs) based on Matrimid® and benzimidazole-linked polymers (BILPs) have been investigated for the separation CO2/N2 and the dependency on the filler porosity. BILPs with two different porosities (BILP-101 and RT-BILP-101) were synthesized through controlling the initial polymerization rate and further characterized by several techniques (DRIFTs, 13C CP/MAS NMR, SEM, TEM, N2 and CO2 adsorption). To investigate the influence of porosity, the two types of fillers were incorporated into Matrimid® to prepare MMMs at varied loadings (8, 16 and 24 wt%). SEM confirmed that both BILP-101 and RT-BILP-101 are well dispered, indicating their good compatibility with the polymeric matrix. The partial pore blockage in the membrane was verified by CO2 adsorption isotherms on the prepared membranes. In the separation of CO2 from a 15:85 CO2:N2 mixture at 308 K, the incorporation of both BILPs fillers resulted in an enhancement in gas permeability together with constant selectivity owing to the fast transport pathways introduced by the porous network. It was noteworthy that the initial porosity of the filler had a large impact in separation permeability. The best improvement was achieved by 24 wt% RT-BILP-101 MMMs, for which the CO2 permeability increases up to 2.8-fold (from 9.6 to 27 Barrer) compared to the bare Matrimid®.","Benzimidazole-linked polymers; CO separation; Mixed-matrix membranes","en","journal article","","","","","","Accepted Author Manuscript","","2020-09-07","","","ChemE/Catalysis Engineering","","",""
"uuid:20bd1de1-f419-47aa-a093-e7356ce6c20d","http://resolver.tudelft.nl/uuid:20bd1de1-f419-47aa-a093-e7356ce6c20d","Synthesis of severe lattice distorted MoS2 coupled with hetero-bonds as anode for superior lithium-ion batteries","Liu, Yanyan (Yanshan University); Zhang, Long (Yanshan University); Wang, Hongqiang (Hebei University); Yu, C. (TU Delft RST/Fundamental Aspects of Materials and Energy); Yan, Xinlin (Technische Universität Wien); Liu, Qiunan (Yanshan University); Xu, Bo (Yanshan University); Wang, Li min (Yanshan University)","","2018","Exploration of advanced anode materials is a highly relevant research topic for next generation lithium-ion batteries. Here, we report severe lattice distorted MoS2 nanosheets with a flower-like morphology prepared with PEG400 as additive, which acts not only as surfactant but importantly, also as reactant. Notably, in the absence of a carbon-related incorporation/decoration, it demonstrates superior electrochemical performance with a high reversible capacity, a good cycling stability, and an excellent rate capability, originated from the advantages of synthesized MoS2 including enlarged interlayer spacing, 1T-like metallic behavior, and coupling of Mo–O–C (and Mo–O) hetero-bonds. PEG-assisted synthesis is believed applicable to other anode materials with a layered structure for lithium-ion batteries.","Lattice distortion; Lithium-ion batteries; MoS; Oxygen-containing groups; Polyethylene glycol","en","journal article","","","","","","","","2020-02-05","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:e679f5d7-2df0-4db6-9f6c-37f735444b27","http://resolver.tudelft.nl/uuid:e679f5d7-2df0-4db6-9f6c-37f735444b27","Integration of real-time traffic management and train control for rail networks: Part 2: Extensions towards energy-efficient train operations","Luan, X. (TU Delft Transport Engineering and Logistics); Wang, Y. (Beijing Jiaotong University); De Schutter, B.H.K. (TU Delft Team Bart De Schutter); Meng, Lingyun (Beijing Jiaotong University); Lodewijks, G. (University of New South Wales); Corman, F. (ETH Zürich)","","2018","We study the integration of real-time traffic management and train control by using mixed-integer nonlinear programming (MINLP) and mixed-integer linear programming (MILP) approaches. In Part 1 of the paper (Luan et al., 2018), three integrated optimization problems, namely the PNLP problem (NLP: nonlinear programming), the PPWA problem (PWA: piecewise affine), and the PTSPO problem (TSPO: train speed profile option), have been developed for real-time traffic management that inherently include train control. A two-level approach and a custom-designed two-step approach have been proposed to solve these optimization problems. In Part 2 of the paper, aiming at energy-efficient train operation, we extend the three proposed optimization problems by introducing energy-related formulations. We first evaluate the energy consumption of a train motion. A set of nonlinear constraints is first proposed to calculate the energy consumption, which is further reformulated as a set of linear constraints for the PTSPO problem and approximated by using a piecewise constant function for the PNLP and PPWA problems. Moreover, we consider the option of regenerative braking and present linear formulations to calculate the utilization of the regenerative energy obtained through braking trains. We focus on two objectives, i.e., delay recovery and energy efficiency, through using a weighted-sum formulation and an ε-constraint formulation. With these energy-related extensions, the nature of the three optimization problems remains same to Part 1. In numerical experiments conducted based on the Dutch test case, we consider the PNLP approach and the PTSPO approach only and compare their performance with the inclusion of the energy-related aspects; the PPWA approach is neglected due to its bad performance, as evaluated in Part 1. According to the experimental results, the PTSPO approach still yields a better performance within the required computation time. The trade-off between train delay and energy consumption is investigated. The results show the possibility of reducing train delay and saving energy at the same time through managing train speed, by up to 4.0% and 5.6% respectively. In our case study, applying regenerative braking leads to a 22.9% reduction of the total energy consumption.","Energy efficient train operation; Integrated optimization; Real-time traffic management; Regenerative braking; Train control","en","journal article","","","","","","Accepted Author Manuscript","","2020-07-18","","","Transport Engineering and Logistics","","",""
"uuid:e681175a-09f1-4ad3-a599-fd2cd876a9d7","http://resolver.tudelft.nl/uuid:e681175a-09f1-4ad3-a599-fd2cd876a9d7","Comparison of Machine Learning Models for Hazardous Gas Dispersion Prediction in Field Cases","Wang, Rongxiao (National University of Defense Technology); Chen, B. (National University of Defense Technology); Qiu, S. (TU Delft Web Information Systems; National University of Defense Technology); Zhu, Zhengqiu (National University of Defense Technology); Wang, Yiduo (National University of Defense Technology); Wang, Yiping (Naval 902 Factory); Qiu, Xiaogang (National University of Defense Technology)","","2018","Dispersion prediction plays a significant role in the management and emergency response to hazardous gas emissions and accidental leaks. Compared with conventional atmospheric dispersion models, machine leaning (ML) models have both high accuracy and efficiency in terms of prediction, especially in field cases. However, selection of model type and the inputs of the ML model are still essential problems. To address this issue, two ML models (i.e., the back propagation (BP) network and support vector regression (SVR) with different input selections (i.e., original monitoring parameters and integrated Gaussian parameters) are proposed in this paper. To compare the performances of presented ML models in field cases, these models are evaluated using the Prairie Grass and Indianapolis field data sets. The influence of the training set scale on the performances of ML models is analyzed as well. Results demonstrate that the integrated Gaussian parameters indeed improve the prediction accuracy in the Prairie Grass case. However, they do not make much difference in the Indianapolis case due to their inadaptability to the complex terrain conditions. In addition, it can be summarized that the SVR shows better generalization ability with relatively small training sets, but tends to under-fit the training data. In contrast, the BP network has a stronger fitting ability, but sometimes suffers from an over-fitting problem. As a result, the model and input selection presented in this paper will be of great help to environmental and public health protection in real applications.","Back propagation network; Field case; Hazardous gas dispersion prediction; Input selection; Support vector regression","en","journal article","","","","","","","","","","","Web Information Systems","","",""
"uuid:5c0c0fa8-2784-4528-8534-0a0f810bcfb9","http://resolver.tudelft.nl/uuid:5c0c0fa8-2784-4528-8534-0a0f810bcfb9","Integration of real-time traffic management and train control for rail networks: Part 1: Optimization problems and solution approaches","Luan, X. (TU Delft Transport Engineering and Logistics); Wang, Y. (Beijing Jiaotong University); De Schutter, B.H.K. (TU Delft Team Bart De Schutter); Meng, Lingyun (Beijing Jiaotong University); Lodewijks, G. (University of New South Wales); Corman, F. (ETH Zürich)","","2018","We study the integration of real-time traffic management and train control by using mixed-integer nonlinear programming (MINLP) and mixed-integer linear programming (MILP) approaches. Three innovative integrated optimization approaches for real-time traffic management that inherently include train control are developed to deliver both a train dispatching solution (including train routes, orders, departure and arrival times at passing stations) and a train control solution (i.e., train speed trajectories). Train speed is considered variable, and the blocking time of a train on a block section dynamically depends on its real speed. To formulate the integrated problem, we first propose an MINLP problem (PNLP), which is solved by a two-level approach. This MINLP problem is then reformulated by approximating the nonlinear terms with piecewise affine functions, resulting in an MILP problem (PPWA). Moreover, we consider a preprocessing method to generate the possible speed profile options for each train on each block section, one of which is further selected by a proposed MILP problem (PTSPO) with respect to safety, capacity, and speed consistency constraints. This problem is solved by means of a custom-designed two-step approach, in order to speed up the solving procedure. Numerical experiments are conducted using data from the Dutch railway network to comparatively evaluate the effectiveness and efficiency of the three proposed approaches with heterogeneous traffic. According to the experimental results, the MILP approach (PTSPO) yields the best overall performance within the required computation time. The experimental results demonstrate the benefits of the integration, i.e., train delays can be reduced by managing train speed.","Delay recovery; Integrated optimization; Mixed integer linear programming (MILP); Real-time traffic management; Train control","en","journal article","","","","","","Accepted Author Manuscript","","2020-07-07","","","Transport Engineering and Logistics","","",""
"uuid:9e215466-bc4a-40f1-96f9-6cdba36441e5","http://resolver.tudelft.nl/uuid:9e215466-bc4a-40f1-96f9-6cdba36441e5","Promoting sensitivity and selectivity of HCHO sensor based on strained InP3 monolayer: A DFT study","Yang, Huiru (Chongqing University); Wang, Zeping (Chongqing University); Ye, H. (TU Delft Electronic Components, Technology and Materials; Chongqing University); Zhang, Kai (Guangdong University of Technology); Chen, X. (TU Delft Electronic Components, Technology and Materials; Chongqing University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2018","Sensitive materials for formaldehyde (HCHO) sensor need high sensitivity and selectivity. The research on two dimensional (2D) sensitive material is growing, and most studies focus on the pristine or modified graphene. So it is essential to introduce other 2D materials into HCHO gas sensor. In this report, the adsorption behaviors of organic gas molecules including C2H6, C2H4, C2H2, C6H6, C2H5OH and HCHO over indium triphosphide (InP3) monolayer were studied by using first-principle atomistic simulations. The calculation results demonstrate that InP3 monolayer has a high sensitivity and selectivity to HCHO than others. By comparing the structures and adsorption results of InP3 monolayer, graphene and single-layered MoS2, it was found that the polarity bonds and steric effect of the site on monolayer play an important role in the detection of HCHO. The effect of strain on the gas/substrate adsorption systems was also studied, implying that the stained InP3 monolayer could enhance the sensitivity and selectivity to HCHO. This study provides useful insights into the gas-surface interaction that may assist future experimental development of 2D material for HCHO sensing and performance optimization based on strain.","First-principles calculation; HCHO sensing; InP monolayer; Strain","en","journal article","","","","","","Accepted author manuscript","","2020-08-09","","","Electronic Components, Technology and Materials","","",""
"uuid:0e384129-0ef3-4e50-968a-efad15e1c1ba","http://resolver.tudelft.nl/uuid:0e384129-0ef3-4e50-968a-efad15e1c1ba","Behaviour change in post-consumer recycling: Applying agent-based modelling in social experiment","Tong, Xin (Peking University); Nikolic, I. (TU Delft Energie and Industrie); Dijkhuizen, B.C.J. (TU Delft System Engineering); van den Hoven, M.F.S. (TU Delft Education and Student Affairs); Minderhoud, M. (TU Delft Policy Analysis); Wäckerlin, N. (TU Delft System Engineering); Wang, T. (TU Delft Signal Processing Systems; Peking University); Tao, Dongyan (Peking University)","","2018","Change in consumer behavior that leads to increased waste separation and recycling has been identified as a critical component of Chinese national strategy for constructing a “Circular Economy”. Various innovative solutions at community level targeting consumer behaviors are emerging in Chinese cities, using information technology that can track the volume and quality of the sorting process. In order to evaluate the potential impact of these novel solutions, we studied the behavioral change of households by initiating an experimental recycling program in a residential community in Beijing, and developed an Agent Based Model based on Theory of Planned Behavior (TPB) to identify key factors in changing behavior. The results show that the Social Norm (SN) has a decisive effect on whether an area starts recycling or not. As to the effectiveness of intervention, the Perceived Behavioral Control (PBC) plays a large role in the determination of the recycling behavior in this study, while the role of attitude is relatively small. The model outcomes can be corroborated with observations in different communities using similar technical solutions. In conclusion, we suggest that efficient local interactions among various stakeholders are needed in forming the social norm and common space that favorite recycling activities at the community level.","Agent-based modelling (ABM); Community-based tool; Recycling; Theory of planned behavior (TPB); Waste separation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2018-09-26","","","Energie and Industrie","","",""
"uuid:422284b9-4646-4549-be75-9552564de16e","http://resolver.tudelft.nl/uuid:422284b9-4646-4549-be75-9552564de16e","Simulation of the Flexural Response of Ultrahigh Performance Fiber-Reinforced Concrete with Lattice Fracture Model","Gu, C. (TU Delft Microlab; TU Delft Materials and Environment; Zhejiang University); Wang, Qiannan (Southeast University); Sun, Wei (Southeast University)","","2018","The flexural response of ultrahigh performance fiber-reinforced concrete (UHPFRC) was simulated based on the lattice fracture model. Fiber was modelled as separated beam that was connected to the matrix with interface beams. The simulated results were compared with the experimental results. Deviations occurred at the late stage of the strain-softening period. But both the strain-hardening behavior and multicracking phenomenon were observed in the simulation. The effects of fiber orientation and fiber content were studied with the lattice fracture model. The flexural strength and toughness of UHPFRC improved as the fibers were aligned distributed or the fiber content increased. The proposed model has the potential to help with the materials design of UHPFRC, and the limitations of the model were also discussed in the paper.","","en","journal article","","","","","","","","","","","Microlab","","",""
"uuid:918eae0b-9e3f-4bec-884f-74f4e04dab09","http://resolver.tudelft.nl/uuid:918eae0b-9e3f-4bec-884f-74f4e04dab09","Generating sparse self-supporting wireframe models for 3D printing using mesh simplification","Liu, Xiuping (Dalian University of Technology); Lin, Liping (Dalian University of Technology); Wu, J. (TU Delft Materials and Manufacturing); Wang, W. (TU Delft Materials and Manufacturing; Dalian University of Technology); Yin, Baocai (Dalian University of Technology); Wang, C.C. (TU Delft Materials and Manufacturing)","","2018","Wireframe models are becoming a popular option in 3D printing. Generating sparse wireframe models using classic mesh simplification methods leads to models that require a lot of support structures in the layer-upon-layer additive process. In this paper we present a mesh simplification method that takes into account the overhang angle. Specifically, we propose a metric for self-supportability. By combining this novel metric together with the classic error metrics for mesh simplification, our method generates sparse wireframe models that need much less supports. Moreover, the operations of vertex position optimization and edge flipping are used to further increase self-supportability of the wireframe models. We demonstrate the effectiveness of the proposed method on a number of 3D models.","3D printing; Mesh simplification; Self-supporting; Wireframe models","en","journal article","","","","","","Accepted author manuscript","","2020-06-15","","","Materials and Manufacturing","","",""
"uuid:4efdd42b-7eac-40ee-8036-4d7b313a7dff","http://resolver.tudelft.nl/uuid:4efdd42b-7eac-40ee-8036-4d7b313a7dff","Analysis of the interaction between moving α/γ interfaces and interphase precipitated carbides during cyclic phase transformations in a Nb-containing Fe-C-Mn alloy","Dong, Haokai (Tsinghua University); Chen, Hao (Tsinghua University); Wang, Wei (Baosteel Research Institute); Zhang, Yongjie (Tohoku University); Miyamoto, Goro (Tohoku University); Furuhara, Tadashi (Tohoku University); Zhang, Chi (Tsinghua University); Yang, Zhigang (Tsinghua University); van der Zwaag, S. (TU Delft Novel Aerospace Materials; Tsinghua University)","","2018","The interaction between moving α/γ interfaces and interphase precipitated (IPd) carbides during the austenite (γ) to ferrite (α) and the ferrite (α) to austenite (γ) transformation has been systematically investigated through cyclic phase transformation experiments for a 0.1C-1.5Mn alloy containing 0.1 wt% Niobium (Nb) and its Nb-free counterpart. Shifts in the critical reaction temperatures during continuous heating and cooling are observed, which are attributed to the pinning force (PF) originating from the IPd carbides present. By applying the Gibbs energy balance (GEB) model to analyze experimental results, the PF was derived to be about 15 J/mol for the α→γ transformation and about 5 J/mol for the γ→α transformation, respectively, both of which are quite small compared to chemical driving force of phase transformations. Moreover, various modified Zener pinning equations have also been used to predict the PF, and it was found that these values are comparable with those obtained from experiments, which suggests that the classical Zener theory still has promising potential for carbide-interface interaction analysis.","Carbide; Interface migration; Interphase precipitation; Phase transformation; Pinning force","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-04-01","","","Novel Aerospace Materials","","",""
"uuid:388fbdaa-82e0-4e93-92a5-9a4ff2b5d175","http://resolver.tudelft.nl/uuid:388fbdaa-82e0-4e93-92a5-9a4ff2b5d175","Temperature susceptibility of a mesophilic anaerobic membrane bioreactor treating saline phenol-containing wastewater","Muñoz Sierra, Julian (TU Delft Sanitary Engineering); Wang, W.W. (TU Delft Sanitary Engineering; Hefei University of Technology); Cerqueda Garcia, D. (TU Delft Sanitary Engineering; Universidad Nacional Autónoma de México); Oosterkamp, M.J. (TU Delft Sanitary Engineering); Spanjers, H. (TU Delft Sanitary Engineering); van Lier, J.B. (TU Delft Sanitary Engineering)","","2018","This study examined the temperature susceptibility of a continuous-flow lab-scale anaerobic membrane bioreactor (AnMBR) to temperature shifts from 35 °C to 55 °C and its bioconversion robustness treating synthetic phenolic wastewater at 16 gNa+.L−1. During the experiment, the mesophilic reactor was subjected to stepwise temperature increases by 5 °C. The phenol conversion rates of the AnMBR decreased from 3.16 at 35 °C to 2.10 mgPh.gVSS−1.d−1 at 45 °C, and further decreased to 1.63 mgPh.gVSS−1.d−1 at 50 °C. At 55 °C, phenol conversion rate stabilized at 1.53 mgPh.gVSS−1.d−1 whereas COD removal efficiency was 38% compared to 95.5% at 45 °C and 99.8% at 35 °C. Interestingly, it was found that the phenol degradation process was less susceptible for the upward temperature shifts than the methanogenic process. The temperature increase implied twenty-one operational taxonomic units from the reactor's microbial community with significant differential abundance between mesophilic and thermophilic operation, and eleven of them are known to be involved in aromatic compounds degradation. Reaching the upper-temperature limits for mesophilic operation was associated with the decrease in microbial abundance of the phyla Firmicutes and Proteobacteria, which are linked to syntrophic phenol degradation. It was also found that the particle size decreased from 89.4 μm at 35 °C to 21.0 μm at 55 °C. The accumulation of small particles and higher content of soluble microbial protein-like substances led to increased transmembrane pressure which negatively affected the filtration performance. Our findings indicated that at high salinity a mesophilic AnMBR can tolerate a temperature up to 45 °C without being limited in the phenol conversion capacity.","AnMBR; Mesophilic; Microbial community; Phenol; Salinity; Temperature susceptibility","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:3a3320a8-5fdc-4e40-a605-afc18b96ea4b","http://resolver.tudelft.nl/uuid:3a3320a8-5fdc-4e40-a605-afc18b96ea4b","Lithium halide coating as an effective intergrain engineering for garnet-type solid electrolytes avoiding high temperature sintering","Zhang, Zhaoshuai (Yanshan University); Zhang, Long (Yanshan University); Yu, C. (TU Delft RST/Storage of Electrochemical Energy); Yan, Xinlin (Technische Universität Wien); Xu, Bo (Yanshan University); Wang, L. (Yanshan University)","","2018","Garnet-type Li7La3Zr2O12 solid electrolytes were commonly prepared by two steps solid-state reaction method, which undergoes high temperature over 1000 °C and thus inevitable for lithium volatilization and formation of secondary phases. Here, we propose a new intergrain architecture engineering of a solution method, to avoid high temperature sintering for preparing lithium halide (LiX) coated garnet-type solid electrolytes, which contain Al and Ta co-doped Li7La3Zr2O12 (Li6.75La3Zr1.75Ta0.25O12, LLZTO) synthesized at 900 °C with cubic structure. Owing to the increased relative density, the improved formability, and the altered ion transport mode from point to face conduction by LiX coating on LLZTO grains, LiX-coated LLZTO samples demonstrate a good Li dendrite suppression ability and a high ionic conductivity that is three orders of magnitude higher than pristine LLZTO. In another way, this result demonstrates the critical role of the grain boundaries on the ion transport for oxide superionic conductors. The present coating method provides a new strategy to prepare brittle solid electrolytes avoiding high temperature sintering.","Coating; Garnet; LiLaZrO; Lithium halides; Solid electrolytes","en","journal article","","","","","","Accepted Author Manuscript","","2020-09-13","","","RST/Storage of Electrochemical Energy","","",""
"uuid:996be03b-dd55-406c-9906-b5ba9b01a970","http://resolver.tudelft.nl/uuid:996be03b-dd55-406c-9906-b5ba9b01a970","Floating node method with domain-based interaction integral for generic 2D crack growths","Kumar, Sachin (National University of Singapore; Indian Institute of Technology Ropar); Wang, Yihe (National University of Singapore); Poh, Leong Hien (National University of Singapore); Chen, B. Y. (TU Delft Aerospace Structures & Computational Mechanics)","","2018","The Floating Node Method (FNM), first developed for modeling the fracture behavior of laminate composites, is here combined with a domain-based interaction integral approach for the generic fracture modeling of quasi-brittle materials from crack nucleation, propagation to final failure. In this framework, FNM is used to represent the kinematics of cracks, crack tips and material interfaces in the mesh. The values of stress intensity factor are obtained from the FNM solution using domain-based interaction integral approach. To demonstrate the accuracy and effectiveness of the proposed method, four benchmark examples of fracture mechanics are considered. Predictions obtained with the current numerical framework compare well against literature/theoretical results.","Bi-material interfacial fracture; Discontinuous crack modeling; Floating node method; Mixed mode fracture; Stress intensity factors","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-12-17","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:527d064a-0cbf-4ffe-9817-da1932cc0d0d","http://resolver.tudelft.nl/uuid:527d064a-0cbf-4ffe-9817-da1932cc0d0d","A Flexible Strategy for Efficient Merging Maneuvers of Connected Automated Vehicles","Chen, N. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); Alkim, Tom (Ministry of Infrastructure and the Environment); van Arem, B. (TU Delft Transport and Planning)","","2018","Merging is a challenging task for automated vehicles. This paper proposes a strategy for connected automated vehicles (CAVs) to guide merging on-ramp vehicles efficiently while ensuring safe interactions with the mainline vehicles. Point-mass kinematic models are used to describe 2-D vehicle motion and receding horizon control is used to generate optimal trajectories of interacting vehicles. The strategy determines the optimal merging time instant for merging vehicles and acceleration of all involved vehicles to minimize deviation from the preceding vehicles' speed, deviation from preferred inter-vehicle gaps, accelerations, and the time spent merging. The strategy builds on a pre-determined order of vehicles passing the conflict zone but is not restricted to fixed merging points as previous research assumes. It resembles human-like behavior in the sense that on-ramp vehicles will accept smaller gaps when approaching the end of the acceleration lane. The performance of the strategy is demonstrated in simulations.","","en","conference paper","American Society of Civil Engineers (ASCE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-01-08","","","Transport and Planning","","",""
"uuid:af9c1089-b779-47c0-b213-18ec64a7d155","http://resolver.tudelft.nl/uuid:af9c1089-b779-47c0-b213-18ec64a7d155","A data-driven approach for optimal design of integrated air quality monitoring network in a chemical cluster","Zhu, Zhengqiu (National University of Defense Technology); Chen, B. (National University of Defense Technology); Qiu, S. (TU Delft Web Information Systems); Wang, Rongxiao (National University of Defense Technology); Wang, Yiping (Naval 902 Factory); Ma, Liang (National University of Defense Technology); Qiu, Xiaogang (National University of Defense Technology)","","2018","The chemical industry is of paramount importance to the world economy and this industrial sector represents a substantial income source for developing countries. However, the chemical plants producing inside an industrial district pose a great threat to the surrounding atmospheric environment and human health. Therefore, designing an appropriate and available air quality monitoring network (AQMN) is essential for assessing the effectiveness of deployed pollution-controlling strategies and facilities. As monitoring facilities located at inappropriate sites would affect data validity, a two-stage data-driven approach constituted of a spatio-temporal technique (i.e. Bayesian maximum entropy) and a multi-objective optimization model (i.e. maximum concentration detection capability and maximum dosage detection capability) is proposed in this paper. The approach aims at optimizing the design of an AQMN formed by gas sensor modules. Owing to the lack of long-term measurement data, our developed atmospheric dispersion simulation system was employed to generate simulated data for the above method. Finally, an illustrative case study was implemented to illustrate the feasibility of the proposed approach, and results imply that this work is able to design an appropriate AQMN with acceptable accuracy and efficiency.","air quality monitoring network; atmospheric dispersion simulation system; Bayesian maximum entropy; multi-objective optimization model","en","journal article","","","","","","","","","","","Web Information Systems","","",""
"uuid:d0bbeda4-e234-4188-9d41-49846d8f481e","http://resolver.tudelft.nl/uuid:d0bbeda4-e234-4188-9d41-49846d8f481e","Energy-efficient shipping: An application of big data analysis for optimizing engine speed of inland ships considering multiple environmental factors","Yan, Xinping (Wuhan University of Technology; MOST); Wang, K. (TU Delft Transport Engineering and Logistics; Wuhan University of Technology); Yuan, Yupeng (Wuhan University of Technology; MOST; University of Cambridge); Jiang, X. (TU Delft Transport Engineering and Logistics); Negenborn, R.R. (TU Delft Transport Engineering and Logistics)","","2018","Energy efficiency of inland ships is significantly influenced by navigational environment, including wind speed and direction as well as water depth and speed. The complexity of the inland navigational environment makes it rather difficult to determine the optimal speeds under different environmental conditions to achieve the best energy efficiency. Route division according to the characteristics of these environmental factors could provide a good solution for the optimization of ship engine speed under different navigational environments. In this paper, the distributed parallel k-means clustering algorithm is adopted to achieve an elaborate route division by analyzing the corresponding environmental factors based on a self-developed big data analytics platform. Subsequently, a ship energy efficiency optimization model considering multiple environmental factors is established through analyzing the energy transfer among hull, propeller and main engine. Then, decisions are made concerning the optimal engine speeds in different segments along the path. Finally, a case study on the Yangtze River is performed to validate the present optimization method. The results show that the proposed method can effectively reduce energy consumption and CO2 emissions of ships.","Big data analysis; Hadoop; Parallel k-means algorithm; Ship energy efficiency; Speed optimization","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-04-01","","","Transport Engineering and Logistics","","",""
"uuid:df844ae0-ee35-410f-8ac7-06154732c702","http://resolver.tudelft.nl/uuid:df844ae0-ee35-410f-8ac7-06154732c702","Electric field tunable superconductor-semiconductor coupling in Majorana nanowires","de Moor, M.W.A. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Bommer, J.D.S. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Xu, D. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Winkler, Georg W. (Microsoft Research); Antipov, Andrey E. (Microsoft Research); Bargerbos, A. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); Wang, Guanzhong (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); van Loo, N. (TU Delft Applied Sciences; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft); op het Veld, R.L.M. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Eindhoven University of Technology; Kavli institute of nanoscience Delft); Gazibegovic, S. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Eindhoven University of Technology; Kavli institute of nanoscience Delft); Car, D. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Eindhoven University of Technology; Kavli institute of nanoscience Delft); Bakkers, E.P.A.M. (TU Delft QN/Bakkers Lab; TU Delft QuTech Advanced Research Centre; Eindhoven University of Technology; Kavli institute of nanoscience Delft); Kouwenhoven, Leo P. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft; Microsoft Quantum Lab Delft); Zhang, H. (TU Delft Applied Sciences; TU Delft QuTech Advanced Research Centre; Kavli institute of nanoscience Delft)","","2018","We study the effect of external electric fields on superconductor-semiconductor coupling by measuring the electron transport in InSb semiconductor nanowires coupled to an epitaxially grown Al superconductor. We find that the gate voltage induced electric fields can greatly modify the coupling strength, which has consequences for the proximity induced superconducting gap, effective g-factor, and spin-orbit coupling, which all play a key role in understanding Majorana physics. We further show that level repulsion due to spin-orbit coupling in a finite size system can lead to seemingly stable zero bias conductance peaks, which mimic the behavior of Majorana zero modes. Our results improve the understanding of realistic Majorana nanowire systems.","Majorana fermions; nanowires; spin-orbit coupling; superconductivity","en","journal article","","","","","","","","","Applied Sciences","","QRD/Kouwenhoven Lab","","",""
"uuid:d8cf233f-316a-4567-821f-aecf7dd1d244","http://resolver.tudelft.nl/uuid:d8cf233f-316a-4567-821f-aecf7dd1d244","High-Performance Back-Illuminated Three-Dimensional Stacked Single-Photon Avalanche Diode Implemented in 45-nm CMOS Technology","Lee, M.J. (TU Delft (OLD)Applied Quantum Architectures; Swiss Federal Institute of Technology); Ronchini Ximenes, A. (TU Delft (OLD)Applied Quantum Architectures); Padmanabhan, P. (TU Delft (OLD)Applied Quantum Architectures; Swiss Federal Institute of Technology); Wang, Tzu Jui (Taiwan Semiconductor Manufacturing Company (TSMC)); Huang, Kuo Chin (Taiwan Semiconductor Manufacturing Company (TSMC)); Yamashita, Yuichiro (Taiwan Semiconductor Manufacturing Company (TSMC)); Yaung, Dun Nian (Taiwan Semiconductor Manufacturing Company (TSMC)); Charbon-Iwasaki-Charbon, E. (Swiss Federal Institute of Technology; Kavli institute of nanoscience Delft)","","2018","We present a high-performance back-illuminated three-dimensional stacked single-photon avalanche diode (SPAD), which is implemented in 45-nm CMOS technology for the first time. The SPAD is based on a P+/Deep N-well junction with a circular shape, for which N-well is intentionally excluded to achieve a wide depletion region, thus enabling lower tunneling noise and better timing jitter as well as a higher photon detection efficiency and a wider spectrum. In order to prevent premature edge breakdown, a P-type guard ring is formed at the edge of the junction, and it is optimized to achieve a wider photon-sensitive area. In addition, metal-1 is used as a light reflector to improve the detection efficiency further in backside illumination. With the optimized 3-D stacked 45-nm CMOS technology for back-illuminated image sensors, the proposed SPAD achieves a dark count rate of 55.4 cps/μm2 and a photon detection probability of 31.8% at 600 nm and over 5% in the 420-920 nm wavelength range. The jitter is 107.7 ps full width at half-maximum with negligible exponential diffusion tail at 2.5 V excess bias voltage at room temperature. To the best of our knowledge, these are the best results ever reported for any back-illuminated 3-D stacked SPAD technologies.","Avalanche photodiode (APD); CMOS image sensor; detector; Geiger-mode avalanche photodiode (G-APD); image sensor; integrated optics device; integrated photonics; light detection and ranging (LiDAR); low light level; optical sensor; photodiode; photomultiplier; photon counting; photon timing; semiconductor; sensor; silicon; single-photon avalanche diode (SPAD); single-photon imaging; standard CMOS technology; three-dimensional fabrication; three-dimensional vision","en","journal article","","","","","","","","","","","(OLD)Applied Quantum Architectures","","",""
"uuid:016c7d54-2ab8-4e07-b055-70c54934bd64","http://resolver.tudelft.nl/uuid:016c7d54-2ab8-4e07-b055-70c54934bd64","Hydrogen sulfide detection properties of Pt-gated AlGaN/GaN HEMT-sensor","Sokolovskij, R. (TU Delft Electronic Components, Technology and Materials; Southern University of Science and Technology; State Key Laboratory of Solid State Lighting); Zhang, Jian (Fudan University; Southern University of Science and Technology); Iervolino, E. (Southern University of Science and Technology); Zhao, Changhui (Southern University of Science and Technology); Santagata, F. (TU Delft Electronic Components, Technology and Materials); Wang, F. (Southern University of Science and Technology; Shenzhen Key Laboratory of the Third Generation Semi-conductor); Yu, Hongyu (Southern University of Science and Technology; Shenzhen Key Laboratory of the Third Generation Semi-conductor); Sarro, Pasqualina M (TU Delft Electronic Components, Technology and Materials); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2018","AlGaN/GaN high electron mobility transistor (HEMT)-based sensors with catalytic platinum gate were micro-fabricated on commercially available epitaxial wafers and extensively characterized for ppm level hydrogen sulfide (H2S) detection for industrial safety applications. High operating temperature above 150 °C enabled large signal variation (ΔIDS) of 2.17 and sensing response of 112% for 90 ppm H2S in dry air as well as high stability across a wide range of biasing conditions. Transient response measurements demonstrated stable operation, superb response and recovery, with good repeatability. The measured sensing signal rise (fall) times reduced from 476 (1316) s to 219 (507) s when the temperature was increased from 200 °C to 250 °C. The response to 90 ppm H2S was 4.5x larger than to H2 and the device showed stable operation over an extended time period.","2DEG; AlGaN/GaN; Gas sensor; HS; HEMT; Pt","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-12-03","","","Electronic Components, Technology and Materials","","",""
"uuid:8740758d-4c08-4369-bc6f-d5cb4fc4f0af","http://resolver.tudelft.nl/uuid:8740758d-4c08-4369-bc6f-d5cb4fc4f0af","Support-free volume printing by multi-axis motion","Dai, C. (TU Delft Materials and Manufacturing); Wang, C.C. (TU Delft Materials and Manufacturing); Wu, Chenming (Tsinghua University); Lefebre, Sylvain (INRIA); Fang, G. (TU Delft Materials and Manufacturing); Liu, Yong-Jin (Tsinghua University)","","2018","This paper presents a new method to fabricate 3D models on a robotic printing system equipped with multi-axis motion. Materials are accumulated inside the volume along curved tool-paths so that the need of supporting structures can be tremendously reduced - if not completely abandoned - on all models. Our strategy to tackle the challenge of tool-path planning for multi-axis 3D printing is to perform two successive decompositions, first volume-to-surfaces and then surfaces-to-curves. The volume-to-surfaces decomposition is achieved by optimizing a scalar field within the volume that represents the fabrication sequence. The field is constrained such that its isovalues represent curved layers that are supported from below, and present a convex surface affording for collision-free navigation of the printer head. After extracting all curved layers, the surfaces-to-curves decomposition covers them with tool-paths while taking into account constraints from the robotic printing system. Our method successfully generates tool-paths for 3D printing models with large overhangs and high-genus topology. We fabricated several challenging cases on our robotic platform to verify and demonstrate its capabilities.","3D printing; Multi-axis motion; Supporting structures; Tool-path generation","en","journal article","","","","","","Accepted author manuscript","","","","","Materials and Manufacturing","","",""
"uuid:0edeacba-9181-4933-b9d4-9f71e9be2cd3","http://resolver.tudelft.nl/uuid:0edeacba-9181-4933-b9d4-9f71e9be2cd3","Leveraging smart lights for passive localization","Wang, Weizheng (Student TU Delft); Zhang, Junwei (Student TU Delft); Wang, Q. (Katholieke Universiteit Leuven); Zuniga, Marco (TU Delft Embedded Systems)","O'Conner, Lisa (editor)","2018","Localization based on visible light is gaining significant attention. But most existing studies rely on a key requirement: the object of interest needs to carry an optical receiver (camera or photodiode). We remove this requirement and investigate the possibility of achieving accurate localization in a passive manner, that is, without requiring objects to carry any optical receiver. To achieve this goal, we exploit the reflective surfaces of objects and the unique propagation properties of LED luminaires. We present geometric models, a testbed implementation, and empirical evaluations to showcase the opportunities and challenges posed by this new type of localization. Overall, we show that our method can track with high accuracy (few centimeters) a subset of an object’s trajectory and it can also identify passively the object’s ID.","Light emitting diodes; Object recognition; Guidelines; Photodiodes; Mirrors; Optical receivers","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-08-17","","","Embedded Systems","","",""
"uuid:e168be70-61c0-42e9-aa6c-a9dd807425a8","http://resolver.tudelft.nl/uuid:e168be70-61c0-42e9-aa6c-a9dd807425a8","Platform for nodal topological superconductors in monolayer molybdenum dichalcogenides","Wang, L. (TU Delft QN/Akhmerov Group; Kavli institute of nanoscience Delft); Rosdahl, T.O. (TU Delft QN/Akhmerov Group; Kavli institute of nanoscience Delft); Sticlet, D.C. (TU Delft QN/Akhmerov Group; Kavli institute of nanoscience Delft; National Institute for Research and Development of Isotopic and Molecular Topics)","","2018","We propose a platform to realize nodal topological superconductors in a superconducting monolayer of MoX2(X=S,Se,Te) using an in-plane magnetic field. The bulk nodal points appear where the spin splitting due to spin-orbit coupling vanishes near the ±K valleys of the Brillouin zone and are six or twelve per valley in total. In the nodal topological superconducting phase, the nodal points are connected by flat bands of zero-energy Andreev edge states. These flat bands, which are protected by chiral symmetry, are present for all lattice-termination boundaries except zigzag.","","en","journal article","","","","","","","","","","","QN/Akhmerov Group","","",""
"uuid:d0fc73d6-3110-45ba-a1d6-cf2f6fa30565","http://resolver.tudelft.nl/uuid:d0fc73d6-3110-45ba-a1d6-cf2f6fa30565","Germanene on single-layer ZnSe substrate: Novel electronic and optical properties","Ye, H. (TU Delft Electronic Components, Technology and Materials; Chongqing University); Hu, F.F. (Chongqing University); Tang, H. (TU Delft Electronic Components, Technology and Materials); Yang, L.W. (General Research Institute for Nonferrous Metals); Chen, X.P. (Chongqing University); Wang, L.G. (General Research Institute for Nonferrous Metals); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2018","In this work, the structural, electronic and optical properties of germanene and ZnSe substrate nanocomposites have been investigated using first-principles calculations. We found that the large direct-gap ZnSe semiconductors and zero-gap germanene form a typical orbital hybridization heterostructure with a strong binding energy, which shows a moderate direct band gap of 0.503 eV in the most stable pattern. Furthermore, the heterostructure undergoes semiconductor-to-metal band gap transition when subjected to external out-of-plane electric field. We also found that applying external strain and compressing the interlayer distance are two simple ways of tuning the electronic structure. An unexpected indirect-direct band gap transition is also observed in the AAII pattern via adjusting the interlayer distance. Quite interestingly, the calculated results exhibit that the germanene/ZnSe heterobilayer structure has perfect optical absorption in the solar spectrum as well as the infrared and UV light zones, which is superior to that of the individual ZnSe substrate and germanene. The staggered interfacial gap and tunability of the energy band structure via interlayer distance and external electric field and strain thus make the germanene/ZnSe heterostructure a promising candidate for field effect transistors (FETs) and nanoelectronic applications.","","en","journal article","","","","","","Accepted author manuscript","","2019-06-21","","","Electronic Components, Technology and Materials","","",""
"uuid:cc05c3e9-8aea-458a-b43f-cda166a1f5ef","http://resolver.tudelft.nl/uuid:cc05c3e9-8aea-458a-b43f-cda166a1f5ef","Condition monitoring of urban rail transit by local energy harvesting","Gao, Mingyuan (Southwest University, Chongqing); Li, Yunwu (Southwest University, Chongqing); Lu, Jun (Southwest Jiaotong University); Wang, Yifeng (Southwest Jiaotong University); Wang, Ping (Southwest Jiaotong University); Wang, L. (TU Delft Pavement Engineering)","","2018","The goal of this study is to develop a vibration-based electromagnetic energy harvesting prototype that provides power to rail-side monitoring equipment and sensors by collecting wheel-rail vibration energy when the train travels. This technology helps power rail–side equipment in off-grid and remote areas. This article introduces the principle, modeling, and experimental test of the system, including (1) an electromagnetic energy harvesting prototype with DC-DC boost converter and lithium battery charge management function, (2) wireless sensor nodes integrated with accelerometer and temperature/humidity sensor, and (3) a vehicle-track interaction model that considers wheel out-of-roundness. Field test results, power consumption, Littlewood–Paley wavelet transform method, and feasibility analysis are reported. An application case of the technology is introduced: the sensor nodes of the wireless sensor network are powered by the electromagnetic energy harvester and lithium battery with DC-DC boost converter, thereby continuously monitoring the railway track state; based on the Littlewood–Paley wavelet analysis of measured railway track acceleration data, the abnormal signal caused by the wheel out-of-roundness can be detected.","Condition monitoring; energy harvesting; magnetic levitation; out-of-roundness; urban rail transit","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:500f9f3f-310d-4a7b-b236-5e1d935204de","http://resolver.tudelft.nl/uuid:500f9f3f-310d-4a7b-b236-5e1d935204de","Investigation on the DC CB Performance during a Current Interruption Failure at First Current Zero","Liu, S. (Xi’an Jiaotong University); Geng, Yingsan (Xi’an Jiaotong University); Popov, M. (TU Delft Intelligent Electrical Power Grids); Wang, Jianhua (Xi’an Jiaotong University); Liu, Zhiyuan (Xi’an Jiaotong University); Zhang, Bojian (Xi’an Jiaotong University)","Falkingham, Lesli T. (editor); Kaneko, Eiji (editor)","2018","The vacuum interrupter is used as the key component of an active DCCB due to its excellent interruption and dielectric recovery characteristics after current zero. The vacuum interrupter can only interrupt the fault currents below the limitation of a critical di/dt and TIV, otherwise it causes a reignition and the interruption failure. In this paper, a detailed active injection DC CB model is developed, considering operation delay of switches, parasitic parameters of switches and thorough control logic. The limitation dielectric strength between the vacuum gap is defined by the cold break down voltage. Based on the numerical modelling, investigation will be performed to see the performance of DC CB with a failure interruption on the first current zero. The simulation results can help to optimize the injection circuit parameters when DC CB has a failure on the first current zero and has to interrupt in the next current zeros. This algorithm will consider predefined threshold of di/dt, chopping current and variable operation time in different scenarios.","active injection; di/dt; fault interruption; HVDC circuit breaker; PSCAD simulation","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-05-03","","","Intelligent Electrical Power Grids","","",""
"uuid:065e62f5-8841-438e-9060-037352e04085","http://resolver.tudelft.nl/uuid:065e62f5-8841-438e-9060-037352e04085","System in package (SiP) technology: Fundamentals, design and applications","Santagata, F. (Guangdong Dongguan Quality Supervision Testing Center); Sun, J. (TU Delft Electronic Components, Technology and Materials); Iervolino, E. (Southern University of Science and Technology); Yu, H. (Southern University of Science and Technology); Wang, F. (Southern University of Science and Technology); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Sarro, Pasqualina M (TU Delft Electronic Components, Technology and Materials); Zhang, Guoyi","","2018","Purpose: The purpose of this paper is to demonstrate a novel 3D system-in-package (SiP) approach. This new packaging approach is based on stacked silicon submount technology. As demonstrators, a smart lighting module and a sensor systems were successfully developed by using the fabrication and assembly process described in this paper. Design/methodology/approach: The stacked module consists of multiple layers of silicon submounts which can be designed and fabricated in parallel. The 3D stacking design offers higher silicon efficiency and miniaturized package form factor. This platform consists of silicon submount design and fabrication, module packaging, system assembling and testing and analyzing. Findings: In this paper, a smart light emitting diode system and sensor system will be described based on stacked silicon submount and 3D SiP technology. The integrated smart lighting module meets the optical requirements of general lighting applications. The developed SiP design is also implemented into the miniaturization of particular matter sensors and gas sensor detection system. Originality/value: SiP has great potential of integrating multiple components into a single compact package, which has potential implementation in intelligent applications.","Gas sensor system; LED module; PM sensor; System-in-package (SiP)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-11-29","","","Electronic Components, Technology and Materials","","",""
"uuid:a958f938-3376-42ea-b0df-55cd6d3fc18c","http://resolver.tudelft.nl/uuid:a958f938-3376-42ea-b0df-55cd6d3fc18c","Lane-Change Intention Estimation for Car-Following Control in Autonomous Driving","Zhang, Yihuan (Tongji University); Lin, Q. (TU Delft Cyber Security); Wang, Jun (Tongji University); Verwer, S.E. (TU Delft Cyber Security); Dolan, John M. (Carnegie Mellon University)","","2018","Car-following is the most general behavior in highway driving. It is crucial to recognize the cut-in intention of vehicles from an adjacent lane for safe and cooperative driving. In this paper, a method of behavior estimation is proposed to recognize and predict the lane change intentions based on the contextual traffic information. A model predictive controller is designed to optimize the acceleration sequences by incorporating the lane-change intentions of other vehicles. The public data set of next generation simulation is labeled and then published as a benchmarking platform for the research community. Experimental results demonstrate that the proposed method can accurately estimate vehicle behavior and therefore outperform the traditional car-following control.","Cooperative car-following; driving behavior estimation; lane change prediction; model predictive control","en","journal article","","","","","","Accepted author manuscript","","","","","Cyber Security","","",""
"uuid:630f93ed-0956-448a-8408-490ddd32b4e8","http://resolver.tudelft.nl/uuid:630f93ed-0956-448a-8408-490ddd32b4e8","Exploring the effects of perception errors and anticipation strategies on traffic accidents - A simulation study","van Lint, J.W.C. (TU Delft Transport and Planning); Calvert, S.C. (TU Delft Transport and Planning); Schakel, W.J. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); Verbraeck, A. (TU Delft Policy Analysis)","","2018","It is remarkable that drivers (on average) can safely navigate through dense traffic at high speeds—conditions in which the time headways between vehicles are in the same order of magnitude as human reaction times. One explanation for this is the ability of drivers to anticipate on the traffic conditions in their surroundings. In this paper, we study, through simulation, the effects of reaction times, errors in perception and anticipation on the probability of accidents on freeways. To this end we extend an existing model for car following and lane changing with a perception and anticipation model inspired by Ensley’s three levels of situational awareness (perception, understanding and projection). By systematically varying driving behavior with different reaction times over a range of perception errors, and anticipation strategies, we compute efficiency effects (capacity and total time spent) and safety effects (the probability density of accidents happening as a function of these different contributing factors and errors). The results provide some evidence that safe driving is robust with respect to perception errors under simple anticipation strategies and small reaction times. When reaction times grow larger, more advanced anticipation strategies are needed to guarantee safe driving.","Anticipation strategies; Awareness; Driving behavior; Perception errors; Traffic safety","en","conference paper","Springer","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-02-02","","","Transport and Planning","","",""
"uuid:3fec5c5f-e069-4435-8f64-0984e0a648c5","http://resolver.tudelft.nl/uuid:3fec5c5f-e069-4435-8f64-0984e0a648c5","Observation of Electron Coherence and Fabry-Perot Standing Waves at a Graphene Edge","Allen, Monica T. (Harvard University); Shtanko, Oles (Massachusetts Institute of Technology); Fulga, Ion C. (Weizmann Institute of Science; IFW Dresden); Wang, Joel I.J. (Massachusetts Institute of Technology); Nurgaliev, Daniyar (Harvard University); Watanabe, Kenji (National Institute for Materials Science); Taniguchi, Takashi (National Institute for Materials Science); Akhmerov, A.R. (TU Delft QN/Akhmerov Group; Kavli institute of nanoscience Delft); Jarillo-Herrero, Pablo (Massachusetts Institute of Technology); Levitov, Leonid S. (Massachusetts Institute of Technology); Yacoby, Amir (Harvard University; Harvard John A. Paulson School of Engineering and Applied Sciences)","","2017","Electron surface states in solids are typically confined to the outermost atomic layers and, due to surface disorder, have negligible impact on electronic transport. Here, we demonstrate a very different behavior for surface states in graphene. We probe the wavelike character of these states by Fabry-Perot (FP) interferometry and find that, in contrast to theoretical predictions, these states can propagate ballistically over micron-scale distances. This is achieved by embedding a graphene resonator formed by gate-defined p-n junctions within a graphene superconductor-normal-superconductor structure. By combining superconducting Aharanov-Bohm interferometry with Fourier methods, we visualize spatially resolved current flow and image FP resonances due to p-n-p cavity modes. The coherence of the standing-wave edge states is revealed by observing a new family of FP resonances, which coexist with the bulk resonances. The edge resonances have periodicity distinct from that of the bulk states manifest in a repeated spatial redistribution of current on and off the FP resonances. This behavior is accompanied by a modulation of the multiple Andreev reflection amplitude on-and-off resonance, indicating that electrons propagate ballistically in a fully coherent fashion. These results, which were not anticipated by theory, provide a practical route to developing electron analog of optical FP resonators at the graphene edge.","Ballistic transport; electron optics; Fabry-Perot interference; graphene edge states; Josephson interferometry","en","journal article","","","","","","","","2018-10-18","","","QN/Akhmerov Group","","",""
"uuid:cda74938-1f82-41f2-aa48-3610d3fd2472","http://resolver.tudelft.nl/uuid:cda74938-1f82-41f2-aa48-3610d3fd2472","Numerical modelling of ice floods in the Ning-Meng reach of the Yellow River basin","Wang, C. (TU Delft Environmental Fluid Mechanics)","Mynett, A.E. (promotor); Popescu, I. (copromotor); Delft University of Technology (degree granting institution)","2017","The Ning-Meng reach of the Yellow River basin is located in the Inner Mongolia region at the Northern part of the Yellow River. Due to the special geographical conditions, the river flow direction is towards the North causing the Ning-Meng reach to freeze up every year in wintertime. Both during the freeze-up and break-up period, unfavourable conditions occur which may cause ice jamming and ice dam formation leading to dike breaching and overtopping of the embankment. Throughout history this has often led to considerable casualties and property loss. Enhanced economic development and human activities in the
region have altered the characteristics of the ice regime in recent decades, leading to several ice disasters during freezing or breaking-up periods. The integrated water resources management plan developed by the Yellow River Conservancy Commission (YRCC) outlines the requirements for water regulation in the upper Yellow River during ice flood periods. YRCC is developing measures that not only safeguard against ice floods, but also assure the availability of
adequate water resources. These provide the overall requirements for developing an ice regime forecasting system including lead-time prediction and required accuracy. In order to develop such a system, numerical modelling of ice floods is an essential component of current research at the YRCC, together with
field observations and laboratory experiments. In order to properly model river ice processes it is necessary to adjust the hydrodynamic equations to account for thermodynamic effects. In this research, hydrological and meteorological data from 1950 to 2010 were used to analyse the characteristics of ice regimes in the past. Also, additional field observations were carried out for ice
flood model calibration and validation. By combining meteorological forecasting models with statistical models, a medium to short range air temperature forecasting model for the Ning-Meng reach was established. These results were used to improve ice formation modelling and prolong lead-time prediction. The numerical ice flood model developed in this thesis for the Ning-Meng reach allows better forecasting of the ice regime and improved decision support for upstream reservoir regulation and taking appropriate measures for disaster risk reduction.","","en","doctoral thesis","CRC Press / Balkema - Taylor & Francis Group","978-1-138-48701-7","","","","Dissertation submitted in fulfillment of the requirements of the Board for Doctorates of Delft University of Technology and of the Academic Board of the UNESCO-IHE Institute for Water Education.","","","","","Environmental Fluid Mechanics","","",""
"uuid:2ef9e517-d6e5-432d-add4-9ed5eee27d99","http://resolver.tudelft.nl/uuid:2ef9e517-d6e5-432d-add4-9ed5eee27d99","Analysis of the evolvement of contact wire wear irregularity in railway catenary based on historical data","Wang, H. (TU Delft Railway Engineering; Southwest Jiaotong University); Nunez, Alfredo (TU Delft Railway Engineering); Liu, Zhigang (Southwest Jiaotong University); Song, Yang (Southwest Jiaotong University); Duan, Fuchuan (Southwest Jiaotong University); Dollevoet, R.P.B.J. (TU Delft Railway Engineering)","","2017","This paper studies the evolvement of the wear irregularity of contact wire using wire thickness data measured yearly from a section of railway catenary. The power spectral density and time–frequency representation based on the wavelet transform are employed for data analysis, with an emphasis on local wear irregularities that are crucial for contact wire condition assessment. To investigate the cause of wear irregularity evolvement and the mutual influence with the pantograph–catenary dynamic interaction, simulations considering the influence of wear irregularity are carried out based on the finite element method. Analyses of the actual wear irregularities and the dynamic contact force under singular and complex wear irregularities are performed. Although the wear irregularity has limited impact on the pantograph–catenary interaction, it can induce the vibration of pantograph and contact wire that will lead to a notable increase of contact force standard deviation. The evolvement of wear irregularity is closely associated with the span length and dropper distribution of catenary structure and the running direction of pantograph. In addition, it is found feasible to detect the wear irregularity based on contact force, on condition that the sampling frequency is high enough to reflect the indicative frequencies.","evolvement and cause; finite element method; historical data; Railway catenary; wavelet transform; wear irregularity","en","journal article","","","","","","","","2019-04-30","","","Railway Engineering","","",""
"uuid:ce04a07d-89fc-470a-9d1a-b6fae9182dae","http://resolver.tudelft.nl/uuid:ce04a07d-89fc-470a-9d1a-b6fae9182dae","Train Trajectory Optimization Methods for Energy-Efficient Railway Operations","Wang, P. (TU Delft Transport and Planning)","Hoogendoorn, S.P. (promotor); Goverde, R.M.P. (promotor); Delft University of Technology (degree granting institution)","2017","Even though rail is more energy efficient than most other transport modes, the enhancement of energy efficiency is an important issue for railways to reduce their contributions to climate change further as well as to save costs and enlarge competition advantages involved. This thesis is motivated by the challenges in improving energy efficiency of train operations. The main objectives are to develop the modelling and solution methods for the train trajectory optimization problem to improve the model accuracy and the computation time, to apply the methods in a train driver advisory system development, and to develop a multi-train trajectory optimization method to solve the delay recovery and the energy-efficient timetabling problem.","Optimizing Train Trajectory; Energy Efficiency; Genetic Algorithms","en","doctoral thesis","TRAIL Research School","978-90-5584-231-5","","","","TRAIL Thesis Series no. T2017/12, the Netherlands TRAIL Research School","","2017-12-31","","","Transport and Planning","","",""
"uuid:573f2a72-1ef1-4831-a3b5-979d71e55abe","http://resolver.tudelft.nl/uuid:573f2a72-1ef1-4831-a3b5-979d71e55abe","Accessing the bottleneck in all-solid state batteries, lithium-ion transport over the solid-electrolyte-electrode interface","Yu, C. (TU Delft RST/Fundamental Aspects of Materials and Energy); Ganapathy, S. (TU Delft RST/Fundamental Aspects of Materials and Energy); van Eck, Ernst R H (Radboud Universiteit Nijmegen); Wang, H.. (TU Delft RST/Fundamental Aspects of Materials and Energy); Basak, S. (TU Delft QN/Zandbergen Lab; Kavli institute of nanoscience Delft); Li, Z. (TU Delft RST/Fundamental Aspects of Materials and Energy); Wagemaker, M. (TU Delft RST/Fundamental Aspects of Materials and Energy)","","2017","Solid-state batteries potentially offer increased lithium-ion battery energy density and safety as required for large-scale production of electrical vehicles. One of the key challenges toward high-performance solid-state batteries is the large impedance posed by the electrode-electrolyte interface. However, direct assessment of the lithium-ion transport across realistic electrode-electrolyte interfaces is tedious. Here we report two-dimensional lithium-ion exchange NMR accessing the spontaneous lithium-ion transport, providing insight on the influence of electrode preparation and battery cycling on the lithium-ion transport over the interface between an argyrodite solid-electrolyte and a sulfide electrode. Interfacial conductivity is shown to depend strongly on the preparation method and demonstrated to drop dramatically after a few electrochemical (dis)charge cycles due to both losses in interfacial contact and increased diffusional barriers. The reported exchange NMR facilitates non-invasive and selective measurement of lithium-ion interfacial transport, providing insight that can guide the electrolyte-electrode interface design for future all-solid-state batteries.","batteries; Solid-state NMR","en","journal article","","","","","","","","","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:bb457e6e-b5b1-42b0-ab42-00228823f91c","http://resolver.tudelft.nl/uuid:bb457e6e-b5b1-42b0-ab42-00228823f91c","Analysis of Bridge Transition Zones in Railways Considering the Moisture Condition of the Ballast and Subballast","Wang, Haoyu (TU Delft Railway Engineering; Roadscanners Oy); Silvast, Mika (Roadscanners Oy); Markine, V.L. (TU Delft Railway Engineering); Wiljanen, Bruce (Roadscanners Oy)","","2017","Transition zones in railway tracks are the locations with considerable changes in vertical support structures, e.g., near bridges. Due to possible water flow constrictions in transition zone structures, there is frequently an increased moisture level in the ballast/subballast layers, which is a potential source of track degradation. This paper presents results of the moisture condition measured in three transition zones using ground penetrating radar, where the ballast/subballast are analyzed. The relationship between the moisture condition and track degradation in the transition zones is studied by comparing it to the longitudinal track level that is measured by the track inspection coaches. A strong connection is found between the high moisture condition and track degradation in the transition zones. The dynamic behavior of the transition zones with high moisture condition is analyzed using the Finite Element method. Differential stiffness and settlement are taken into consideration in the transition zone model, which is also coupled with a vehicle. The ballast/subballast layers are modelled as solid elements. Increased moisture conditions are considered as a reduction of elastic modulus, according to laboratory findings. Results show that high moisture leads to an increase of dynamic wheel loads in the transition zone, which explains the connection and confirms that the high moisture condition is a source of transition zone problems","bridge transition zone; railway; moisture condition; ballast; finite element method; track degradation; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:1b28b9b6-43c7-47a2-b299-d8dbf0d5ee70","http://resolver.tudelft.nl/uuid:1b28b9b6-43c7-47a2-b299-d8dbf0d5ee70","Advances in Modelling Connected and Automated Vehicles","Qu, Xiaobo (University of Technology Sydney); Li, Xiaopeng (University of South Florida Tampa); Wang, M. (TU Delft Transport and Planning); Dixit, Vinayak (University of New South Wales)","","2017","","","en","contribution to periodical","","","","","","","","","","","Transport and Planning","","",""
"uuid:72603e00-09dc-4a68-94ee-1f0878dedd4d","http://resolver.tudelft.nl/uuid:72603e00-09dc-4a68-94ee-1f0878dedd4d","Next Generation Automotive DeNOX Catalysts: Ceria What Else?","Wang, Y. (TU Delft ChemE/Catalysis Engineering)","Makkee, M. (promotor); Kapteijn, F. (promotor); Delft University of Technology (degree granting institution)","2017","Nitrogenoxides (NOx, including NO and NOx) are a group of hazardous, toxic and harmfulgasses, which have an adverse effect on both environment and human health,e.g., acid rain, photochemical smog, and affecting the human respiratorysystem. The NOx concentration in most of the EUcities exceeds the EU annual limit value (40 μg/m3). Around40% of the emitted NOx is attributedto transport related emissions. In currently applicable Euro 6, the real NOx emissionfrom a diesel car is on average 400% than the Euro 6 regulation limit allows ifmeasured under more realistic driving conditions. Although NSR and SCR DeNOx systemshave been broadly investigated and commercially applied with the aim to reduceNOx emissions from lean burn engines,some common problems still exist, e.g., a narrow temperature window and a lowgas hourly space velocity (up to 50.000 L/L/h)in order to convert the NOx selectivelyinto Nx. Due to the in practice high NOxemissionfrom September 2017 additional legislation will be in force to arrive at a morerealistic determination of the highly dynamic NOxemissionby among others the introduction of the real driving emission (RDE) test in thecertification procedure. The Di-Air (Diesel NOxaftertreatment by Adsorbed Intermediate Reductants) system was developed by Toyota(2011-2012) and is still under development. This Di-Air system showed promiseby yielding a high NOx conversion,especially at high temperature (up to 600 ∘C) and high gas hourly space velocity (up to 125.000 L/L/h).This system opts to meet the future stringent NOxreductionrequirements under RDE test conditions (Chapter 1)…","Ceria; NOx; TAP; Di-Air","en","doctoral thesis","","978-94-6186-859-6","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:573183d0-925f-4327-84d7-6f6dc0818026","http://resolver.tudelft.nl/uuid:573183d0-925f-4327-84d7-6f6dc0818026","Electron transport and room temperature single-electron charging in 10 nm scale PtC nanostructures formed by electron beam induced deposition","Durrani, Z. A.K. (Imperial College London); Jones, M. E. (Imperial College London); Wang, C. (Imperial College London); Scotuzzi, M. (TU Delft ImPhys/Charged Particle Optics); Hagen, C.W. (TU Delft ImPhys/Charged Particle Optics)","","2017","Nanostructures of platinum-carbon nanocomposite material have been formed by electron-beam induced deposition. These consist of nanodots and nanowires with a minimum size ∼20 nm, integrated within ∼100 nm nanogap n-type silicon-on-insulator transistor structures. The nanodot transistors use ∼20 nm Pt/C nanodots, tunnel-coupled to Pt/C nanowire electrodes, bridging the Si nanogaps. Roomerature single-electron transistor operation has been measured, and single-electron current oscillations and 'Coulomb diamonds' observed. In nanowire transistors, the temperature dependence from 290 to 8 K suggests that the current is a combination of thermally activated and tunnelling transport of carriers across potential barriers along the current path, and that the Pt/C is p-type at low temperature.","Electron beam induced deposition; single electron transistor; single electron transport","en","journal article","","","","","","","","2018-11-03","","","ImPhys/Charged Particle Optics","","",""
"uuid:fafbbfcb-9ed1-4920-8b9b-e4e64d143daf","http://resolver.tudelft.nl/uuid:fafbbfcb-9ed1-4920-8b9b-e4e64d143daf","Electromagnetic Design of High Frequency PFC Boost Converters using Gallium Nitride Devices","Wang, W. (TU Delft DC systems, Energy conversion & Storage)","Ferreira, Jan Abraham (promotor); Delft University of Technology (degree granting institution)","2017","Throughout the history of power electronics, main driving force of developments is attribute to innovations in power semiconductor technology. With continuous technical improvements in the past 30 years, Si devices, being the most widely used power semiconductor technology, are approaching physical limits e.g. breakdown field, thermal conductivity, etc. of the basic material. Performances of power converters such as efficiency, power density, etc., therefore, has entered into a stage that further improvements are not likely to happen without revolutionary advance in power semiconductor technology. GaN power semiconductor devices, judging from the wide bandgap nature of its material, have the potential of outperforming conventional Si counterparts in measures of high voltage, high temperature and high frequency operations. Capabilities of a GaN device, however, is influenced by more issues, which, apart from material properties, also include die design and fabrication approaches, device packaging technologies, how they are used in an application, etc. In fact, at this stage, available GaN transistors are mostly of lateral structure and, as a consequence, confined to low voltage ones (<1kW) while maximum junction temperature of these products is limited to 175 °C because of the lack of suitable packaging technologies. So far, high frequency operation performance of GaN power semiconductors is unknown and needs to be investigated. This thesis explores high frequency operation potentials of single-die, normally-off GaN power semiconductors that are suited for high voltage, low current applications. The exploration is carried out by means of conducting loss modeling of GaN transistors, uncovering desirable operation conditions of GaN devices for high frequency operations according to analysed results from the model, identifying optimal topologies and operation modes in power converters that can facilitate such conditions for GaN to achieve optimal utilization of the new technology and demonstrating potentials of GaN power semiconductors in an application with all the developed techniques employed.","","en","doctoral thesis","","978-94-028-0825-4","","","","","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:c97fa7db-db06-47ce-8107-5f831f3eab69","http://resolver.tudelft.nl/uuid:c97fa7db-db06-47ce-8107-5f831f3eab69","Local human activities overwhelm decreased sediment supply from the Changjiang River: Continued rapid accumulation in the Hangzhou Bay-Qiantang Estuary system","Xie, Dongfeng (Zhejiang Institute of Hydraulics and Estuary); Pan, Cunhong (Zhejiang Institute of Hydraulics and Estuary); Wu, Xiuguang (Zhejiang Institute of Hydraulics and Estuary); Gao, Shu (Shanghai Estuarine and Coastal Science Research Center); Wang, Zhengbing (TU Delft Coastal Engineering)","","2017","We investigate the morphological responses of the Hangzhou Bay, China, located immediately south of the Changjiang Estuary, to the drastic reduction of the sediment load from the Changjiang River and the large-scale coastal embankment schemes over past decades. The spatial patterns of deposition and erosion, sediment volume changes, and the hydrodynamic and sediment dynamic feedback were analyzed, on the basis of historical bathymetric and hydrographic data. The results show that the sedimentation rates in the bay have generally increased rather than decreased over the past decades, despite bed erosion having occurred in the northern bay-mouth. This observation reveals that the influence of the reduction in the Changjiang River sediment supply on the morphological evolution of Hangzhou Bay has to date been insignificant, mainly due to the buffering effect of existing sediment in the outer Changjiang Estuary. The morphological change is mainly related to the implementation process of the coastal embankment. Sediment accumulation induced by progressive seaward coastal embankment has resulted in seaward aggradation from the Qiantang Estuary towards Hangzhou Bay. Analysis of the annually-averaged high and low tidal levels, and durations of rising and falling tides reveals that flood dominance in the inner bay has been increased, due to the coastal embankment and sediment accumulation. The ratio between annually-averaged rising tide and falling tide durations have decreased from 0.85 to 0.63. The tidal prism at the interface between the inner and outer bay has decreased by about 25% since the 1980s, while the net landward sediment flux has been intensified to a certain extent, which is responsible for the intensifying sedimentation in the inner bay. The local human activities have overwhelm the decreased sediment from the Changjiang River. Although the coastal embankment will cease in the near future, the morphological response to human activities is expected to continue on for a longer time.","Changjiang Estuary; Hangzhou Bay; Morphology; Sediment load; Sediment transport; Tidal asymmetry","en","journal article","","","","","","","","2019-08-22","","","Coastal Engineering","","",""
"uuid:d8c3c582-af01-4228-aaac-fc363054cd35","http://resolver.tudelft.nl/uuid:d8c3c582-af01-4228-aaac-fc363054cd35","Analytical prediction model for non-symmetric fatigue crack growth in Fibre Metal Laminates","Wang, W. (TU Delft Structural Integrity & Composites); Rans, C.D. (TU Delft Structural Integrity & Composites); Benedictus, R. (TU Delft Aerospace Structures & Materials)","","2017","This paper proposes an analytical model for predicting the non-symmetric crack growth and accompanying delamination growth in FMLs. The general approach of this model applies Linear Elastic Fracture Mechanics, the principle of superposition, and displacement compatibility based on the understanding of deformation behaviour in eccentrically cracked metal panels. The non-symmetric crack growth behaviour of two crack tips and accompanying asymmetric load transfer from the eccentrically cracked metal layers to the intact bridging fibres are successfully predicted with the model. The predicted crack growth rates and delamination evolution are compared to test data, good correlation is observed.","Crack opening displacement; Fibre metal laminates; Non-symmetric crack; Stress intensity factor","en","journal article","","","","","","","","2019-07-06","","Aerospace Structures & Materials","Structural Integrity & Composites","","",""
"uuid:24516d5d-94ae-4cc6-a644-ed1b0343b8d6","http://resolver.tudelft.nl/uuid:24516d5d-94ae-4cc6-a644-ed1b0343b8d6","Self-management support system for renal transplant patients: Understanding adherence and acceptance","Wang, W. (TU Delft Interactive Intelligence)","Neerincx, M.A. (promotor); Brinkman, W.P. (promotor); Delft University of Technology (degree granting institution)","2017","Computer-based support for disease self-management has been proposed for chronic patients to stimulate early awareness of disease changes, facilitate patients’ autonomy, and reduce demands on health care resources. Renal transplant patients need lifelong care and can be viewed as chronically ill: they visit hospital regularly to monitor their blood level creatinine and blood pressure. They should also benefit from self-management as other chronic patients do. For the renal transplant patients, a self-management support system (SMSS) was designed and tested, with which they could conduct selfmeasuring regularly to check the renal function and get corresponding feedback. In the study, there were three feedback categories: (1) alright, and therefore patients did not have to take an extra action; (2) mild concern, and therefore patients were requested to measure again; and (3) concern, and therefore patients were advised to contact the hospital. To conduct self-management safely, it is important for the patients to follow the protocol and the system feedback. Therefore, to understand these patients’ selfmanagement behaviour, preferences, and adherence, this thesis investigates possible influencing factors for them to adhere to and accept the SMSS. The study entailed two related research lines: a lab study line that focused on the user interface design of a SMSS, and a clinical trial line that focused on patients’ acceptance and adherence of a SMSS…","self-management support system; user interface; renal transplant patient; adherence; acceptance; attitude","en","doctoral thesis","","978-94-6186-831-2","","","","","","","","","Interactive Intelligence","","",""
"uuid:a817cd87-749e-4747-ac86-ed3e29200b43","http://resolver.tudelft.nl/uuid:a817cd87-749e-4747-ac86-ed3e29200b43","Thermo-elastic optical coherence tomography","Wang, Tianshi (Erasmus MC); Pfeiffer, Tom (University of Lübeck); Wu, Min (Erasmus MC); Wieser, Wolfgang (Optores GmbH); Amenta, Gaetano (Erasmus MC); Draxinger, Wolfgang (University of Lübeck); van der Steen, A.F.W. (TU Delft ImPhys/Acoustical Wavefield Imaging; Erasmus MC; Chinese Academy of Sciences); Huber, Robert (University of Lübeck); Van Soest, Gijs (Erasmus MC)","","2017","The absorption of nanosecond laser pulses induces rapid thermo-elastic deformation in tissue. A sub-micrometer scale displacement occurs within a few microseconds after the pulse arrival. In this Letter, we investigate the laser-induced thermo-elastic deformation using a 1.5 MHz phase-sensitive optical coherence tomography (OCT) system. A displacement image can be reconstructed, which enables a new modality of phase-sensitive OCT, called thermo-elastic OCT. An analysis of the results shows that the optical absorption is a dominating factor for the displacement. Thermo-elastic OCT is capable of visualizing inclusions that do not appear on the structural OCT image, providing additional tissue type information.","","en","journal article","","","","","","","","","","","ImPhys/Acoustical Wavefield Imaging","","",""
"uuid:c204bb8b-b7dc-4201-9a28-9e8773ea09b3","http://resolver.tudelft.nl/uuid:c204bb8b-b7dc-4201-9a28-9e8773ea09b3","Oxygen Vacancies in Reduced Rh/ and Pt/Ceria for Highly Selective and Reactive Reduction of NO into N2 in excess of O2","Wang, Y. (TU Delft ChemE/Catalysis Engineering); Oord, Ramon (Universiteit Utrecht); van den Berg, D. (TU Delft ChemE/Catalysis Engineering); Weckhuysen, Bert M. (Universiteit Utrecht); Makkee, M. (TU Delft ChemE/Catalysis Engineering)","","2017","Currently commercial NOx removal (DeNOx) abatement systems for lean-burn engines exceed regulation limits on the road for NOx emissions. Commercial DeNOx catalysts exhibit poor performance in the selective conversion of NO to N2, especially at high temperature and high gas hourly space velocities (GHSV). In this study, oxygen vacancies of reduced ceria and Pt/ or Rh/ceria are found to be the efficient and selective catalytic sites for NO reduction to N2. Even at low concentrations, NO can compete with an excess of O2 at 600 °C and a high GHSV of 170 000 L L−1 h−1, conditions in which SCR and NSR DeNOx system are not able to function well. N2O is not detected over the whole range of conditions, whereas NO2 is only formed upon oxidation of the catalyst, after both NO and O2 start to appear. For consideration of the fuel economy, the working temperature should be between 250 and 600 °C. Above 600 °C, most of the injected fuel was combusted with O2. Below 250 °C, ceria support will not be reduced by fuel and the oxidation rate of the deposited carbon through oxygen from ceria lattice will be too low.","ceria; environmental catalysis; NO reduction; noble metals; selectivity","en","journal article","","","","","","","","2018-06-20","","","ChemE/Catalysis Engineering","","",""
"uuid:0033d665-c630-4976-8cc4-30425866164c","http://resolver.tudelft.nl/uuid:0033d665-c630-4976-8cc4-30425866164c","Hydroclimatic variability and predictability: A survey of recent research","Koster, Randal D. (NASA Goddard Space Flight Center); Betts, Alan K. (Atmospheric Research); Dirmeyer, Paul A. (George Mason University); Bierkens, Marc (Universiteit Utrecht); Bennett, Katrina E. (Los Alamos National Laboratory); Déry, Stephen J. (University of Northern British Columbia); Evans, Jason P. (University of New South Wales); Fu, Rong (University of California); Hernandez, Felipe (University of Pittsburgh); Ruby Leung, L. (Pacific Northwest National Laboratory); Liang, Xu (University of Pittsburgh); Masood, Muhammad (Bangladesh Water Development Board (BWDB)); Savenije, Hubert (TU Delft Water Resources); Wang, Guiling (University of Connecticut); Yuan, Xing (Chinese Academy of Sciences)","","2017","Recent research in large-scale hydroclimatic variability is surveyed, focusing on five topics: (i) variability in general, (ii) droughts, (iii) floods, (iv) land-atmosphere coupling, and (v) hydroclimatic prediction. Each surveyed topic is supplemented by illustrative examples of recent research, as presented at a 2016 symposium honoring the career of Professor Eric Wood. Taken together, the recent literature and the illustrative examples clearly show that current research into hydroclimatic variability is strong, vibrant, and multifaceted.","","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:227c60c4-f286-4223-b7a2-c378b6c0fec0","http://resolver.tudelft.nl/uuid:227c60c4-f286-4223-b7a2-c378b6c0fec0","Efficient and thermally stable blue-emitting Ce3+ doped LaAl(Si6−zAlz)(N10−zOz) (JEM:Ce) phosphors for white LEDs","Wang, Chun Yun (Hokkaido University; National Institute for Materials Science); ten Kate, O.M. (TU Delft ChemE/Product and Process Engineering; National Institute for Materials Science); Takeda, Takashi (Hokkaido University; National Institute for Materials Science); Hirosaki, Naoto (National Institute for Materials Science)","","2017","La2O3, LaN, Si3N4, AlN and CeO2 have been used as starting materials to synthesize Ce doped LaAl(Si6−zAlz)(N10−zOz) (z ≈ 1, termed the JEM phase) phosphors, via a solid-state reaction method in a gas pressure furnace at a high temperature. Nearly single phase JEM:Ce phosphors have been obtained by carefully controlling the synthesis conditions. The 5% Ce doped JEM phosphor displays a broad excitation band extending from UV to 425 nm, with a maximum at 355 nm. Excitation with 355 nm light results in a Ce3+ 5d–4f emission band (FWHM = 81 nm) centered at 430 nm, with a high internal quantum efficiency of 75%. The emission of the JEM:0.01Ce phosphor has only quenched 3% at room temperature as compared to the intensity at 4 K and still 57% of the luminescence is left at 573 K, which is superior to JEM:Eu phosphors. These performances make JEM:Ce phosphors very promising blue-emitting phosphors for white LED applications.","","en","journal article","","","","","","","","2018-07-15","","","ChemE/Product and Process Engineering","","",""
"uuid:81d9473e-667e-4301-bd48-f7f0218974af","http://resolver.tudelft.nl/uuid:81d9473e-667e-4301-bd48-f7f0218974af","Scalable information extraction from point cloud data obtained by mobile laser scanner","Wang, J. (TU Delft Optical and Laser Remote Sensing)","Menenti, M. (promotor); Lindenbergh, R.C. (copromotor); Delft University of Technology (degree granting institution)","2017","The rise of intelligent transportation, autonomous driving and 3D virtual cities demands highly accurate and regularly updated 2D and 3D maps. However, traditional surveying andmapping techniques are inadequate as they are labor intensive and cost inefficient. Mobile Laser Scanning (MLS) systems, which combine Light Detection and Ranging (LiDAR) with navigation techniques, are able to acquire highly accurate 3D measurements of road environments.","Mobile Laser Scanning; voxels; octrees; geometric information; individual tree separation; object recognition","en","doctoral thesis","","978-94-92683-65-6","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:4710d27e-a19a-42fb-8c6b-ef0d6c0bceaf","http://resolver.tudelft.nl/uuid:4710d27e-a19a-42fb-8c6b-ef0d6c0bceaf","Identification of the catenary structure wavelength using pantograph head acceleration measurements","Wang, H. (TU Delft Railway Engineering); Liu, Zhigang (Southwest Jiaotong University); Nunez, Alfredo (TU Delft Railway Engineering); Dollevoet, R.P.B.J. (TU Delft Railway Engineering)","","2017","For the condition monitoring of railway catenaries, the potential utilization of pantograph head (pan-head) vertical acceleration instead of pantograph-catenary contact force is discussed in this paper. In order to establish a baseline of the pan-head acceleration before it can be used for health condition monitoring, one of the essential frequency components, namely the catenary structure wavelength (CSW) is studied. Based on insitu measurements and feature analysis of the pan-head acceleration signal, an adaptive signal filtering approach is proposed to realize the identification of the CSWs. Preliminary results suggest that the CSWs contained in the pan-head acceleration can be reliably identified by the proposed filtering approach.","Adaptive signal filtering; Catenary health condition monitoring; Catenary structure wavelength; Identification; In-situ measurements; Pantograph head acceleration","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Accepted Author Manuscript","","","","","Railway Engineering","","",""
"uuid:f19b6c3d-ca3a-49a6-9ba5-23d2dd67441e","http://resolver.tudelft.nl/uuid:f19b6c3d-ca3a-49a6-9ba5-23d2dd67441e","Fe3O4 nanoparticles coated with a guanidinium-functionalized polyelectrolyte extend the pH range for phosphate binding","Paltrinieri, L. (TU Delft OLD ChemE/Organic Materials and Interfaces; Wetsus, Centre for Sustainable Water Technology); Wang, M. (TU Delft ChemE/Delft Ingenious Design); Sachdeva, S. (TU Delft OLD ChemE/Organic Materials and Interfaces); Besseling, N.A.M. (TU Delft OLD ChemE/Organic Materials and Interfaces); Sudhölter, Ernst J. R. (TU Delft OLD ChemE/Organic Materials and Interfaces); de Smet, L.C.P.M. (TU Delft OLD ChemE/Organic Materials and Interfaces; Wetsus, Centre for Sustainable Water Technology; Wageningen University & Research)","","2017","In this work commercially available Fe3O4 NPs were coated with polyallylamine hydrochloride (PAH) and PAH functionalized with guanidinium groups (PAH–Gu) for investigating the phosphate adsorption properties under alkaline conditions. The coating can be prepared easily and rapidly and results in Fe3O4 NPs with improved properties related to phosphate binding and colloidal stability. At a low initial phosphate concentration (2 mg L−1), the novel Fe3O4@PAH–Gu material was able to remove phosphate rather independently of the pH condition (4.0, 3.6 and 3.7 mg g−1 at pH = 5, 8 and 10, respectively), whereas for the uncoated Fe3O4 NPs the amount of adsorbed phosphate drops by >75% upon changing from acidic to alkaline conditions (0.84 mg g−1 at pH = 10). Under alkaline conditions, the fastest adsorption was observed for Fe3O4@PAH–Gu followed by Fe3O4@PAH and Fe3O4. This can be related to the additional interaction forces due to the presence of primary amine groups (in PAH and PAH–Gu) and Gu groups (in PAH–Gu only) in coatings. Over 80% of the phosphate adsorbed on the novel Fe3O4@PAH–Gu material was successfully desorbed and the coated NPs were re-used over three adsorption/desorption cycles. This work will stimulate the design and preparation of functionalized polyelectrolytes for an extended area of applications, especially for the selective removal of target compounds from wastewater.","","en","journal article","","","","","","","","","","","OLD ChemE/Organic Materials and Interfaces","","",""
"uuid:de88ab1c-45fd-4f83-855e-ec342fb030b3","http://resolver.tudelft.nl/uuid:de88ab1c-45fd-4f83-855e-ec342fb030b3","Tidal controls on river delta morphology","Hoitink, A.J.F. (Wageningen University & Research); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); Vermeulen, B. (University of Twente; Wageningen University & Research); Huismans, Y (Deltares); Kästner, K (Wageningen University & Research)","","2017","River delta degradation has been caused by extraction of natural resources, sediment retention by reservoirs, and sea-level rise. Despite global concerns about these issues, human activity in the world’s largest deltas intensifies. Harbour development, construction of flood defences, sand mining and land reclamation emerge as key contemporary factors that exert an impact on delta morphology. Tides interacting with river discharge can play a crucial role in the morphodynamic development of deltas under pressure. Emerging insights into tidal controls on river delta morphology suggest that—despite the active morphodynamics in tidal channels and mouth bar regions—tidal motion acts to stabilize delta morphology at the landscape scale under the condition that sediment import during low flows largely balances sediment export during high flows. Distributary channels subject to tides show lower migration rates and are less easily flooded by the river because of opposing non-linear interactions between river discharge and the tide. These interactions lead to flow changes within channels, and a more uniform distribution of discharge across channels. Sediment depletion and rigorous human interventions in deltas, including storm surge defence works, disrupt the dynamic morphological equilibrium and can lead to erosion and severe scour at the channel bed, even decades after an intervention.","","en","journal article","","","","","","","","2018-01-01","","","Coastal Engineering","","",""
"uuid:57e7bbeb-a3ad-4879-95c1-f5b99958e7be","http://resolver.tudelft.nl/uuid:57e7bbeb-a3ad-4879-95c1-f5b99958e7be","High-Performance and Low-Cost Sodium-Ion Anode Based on a Facile Black Phosphorus-Carbon Nanocomposite","Peng, B. (TU Delft ChemE/Materials for Energy Conversion and Storage; Renmin University of China); Xu, Y. (TU Delft ChemE/Materials for Energy Conversion and Storage); Liu, Kai (Renmin University of China); Wang, Xiaoqun (Renmin University of China; Shanghai Jiao Tong University); Mulder, F.M. (TU Delft ChemE/Materials for Energy Conversion and Storage)","","2017","Black phosphorus (BP) has received increasing research attention as an anode material in sodium-ion batteries (SIBs), owing to its high capacity, electronic conductivity, and chemical stability. However, it is still challenging for BP-based SIB anodes to achieve a high electrochemical performance utilizing cost-effective materials and synthetic methods. This work presents a sodium-ion anode based on a BP-carbon nanocomposite synthesized from commercial red phosphorus and low-cost super P carbon black. Intimate interactions between BP and carbon are present, which helps to maintain the electrical conduction during cycling and, therefore, a high cycling stability is achieved. It exhibits a high capacity retention of 1381mAhg-1 for sodium-ion storage after 100 cycles, maintaining 90.5% of the initial reversible capacity. Such high performance/materials cost ratio may provide direction for future phosphorus-based anodes in high energy density SIBs.","Anode materials; Black phosphorus; Nanocomposites; Sodium-ion batteries","en","journal article","","","","","","","","2017-12-01","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:aa05fea5-1704-49d9-9b0e-84c716fd8e5f","http://resolver.tudelft.nl/uuid:aa05fea5-1704-49d9-9b0e-84c716fd8e5f","Using metro smart card data to model location choice of after-work activities: An application to Shanghai","Wang, Y. (TU Delft Transport and Planning); Correia, Gonçalo (TU Delft Transport and Planning); de Romph, E. (TU Delft Transport and Planning; TNO); Timmermans, H. J.P.(Harry) (Eindhoven University of Technology)","","2017","A location choice model explains how travellers choose their trip destinations especially for those activities which are flexible in space and time. The model is usually estimated using travel survey data; however, little is known about how to use smart card data (SCD) for this purpose in a public transport network. Our study extracted trip information from SCD to model location choice of after-work activities. We newly defined the metrics of travel impedance in this case. Moreover, since socio-demographic information is missing in such anonymous data, we used observable proxy indicators, including commuting distance and the characteristics of one's home and workplace stations, to capture some interpersonal heterogeneity. Such heterogeneity is expected to distinguish the population and better explain the difference of their location choice behaviour. The approach was applied to metro travellers in the city of Shanghai, China. As a result, the model performs well in explaining the choices. Our new metrics of travel impedance to access an after-work activity result in a better model fit than the existing metrics and add additional interpretability to the results. Moreover, the proxy variables distinguishing the population seem to influence the choice behaviour and thus improve the model performance.","demand forecast; discrete choice model; location choice modelling; Public transport; smart card data; transport planning","en","journal article","","","","","","","","2019-08-01","","","Transport and Planning","","",""
"uuid:886516fe-764c-4d15-8968-406ad9ee2eb1","http://resolver.tudelft.nl/uuid:886516fe-764c-4d15-8968-406ad9ee2eb1","Car-following Behavior Model Learning Using Timed Automata","Zhang, Yihuan (Tongji University); Lin, Q. (TU Delft Cyber Security); Wang, Jun (Tongji University); Verwer, S.E. (TU Delft Cyber Security)","Dochain, D. (editor); Henrion, D. (editor); Peaucelle, D. (editor)","2017","Learning driving behavior is fundamental for autonomous vehicles to “understand” traffic situations. This paper proposes a novel method for learning a behavioral model of car-following using automata learning algorithms. The model is interpretable for car-following behavior analysis. Frequent common state sequences are extracted from the model and clustered as driving patterns. The Next Generation SIMulation dataset on the I-80 highway is used for learning and evaluating. The experimental results demonstrate high accuracy of car-following model fitting.","real-time automata learning; state sequence clustering; car-following behavior; piece-wise fitting","en","conference paper","Elsevier","","","","","","","","","","Cyber Security","","",""
"uuid:d7a38a53-828d-4822-b565-c4b9cb424434","http://resolver.tudelft.nl/uuid:d7a38a53-828d-4822-b565-c4b9cb424434","Optimization of culturing conditions for isolated Arthrobacter sp. ZXY-2, an effective atrazine-degrading and salt-adaptive bacterium","Zhao, X. (TU Delft Sanitary Engineering; Harbin Institute of Technology); Wang, Li (Harbin Institute of Technology); Du, Linna (Wenzhou Vocational College of Science and Technology); Yang, Jixian (Harbin Institute of Technology); Dong, Jing (Harbin Institute of Technology); Ma, Fang (Harbin Institute of Technology)","","2017","The increasing salinity in aquatic environments has had a negative impact on the biodegradation of atrazine, an extensively used herbicide which has been proven to pollute soil and water ecosystems. In the present study, a novel atrazine-degrading strain (ZXY-2) was isolated from industrial wastewater and identified as the Arthrobacter genus with the 16S rRNA gene. Results indicated that the strain showed a high salinity tolerance, and was able to tolerate NaCl concentrations up to 10% (w/w). Plackett–Burman (PB) multifactorial design and response surface methodology (RSM) were then employed to optimize the culturing conditions. Results showed that among the selected fifteen factors, six contributing factors were obtained. Subsequently, by employing the RSM to model and optimize atrazine degradation, a biodegradation efficiency of 12.73 mg L−1 h−1 was reached under optimal conditions (34.04 °C, pH 9.0, inoculum size 10% (v/v), 2.212 g L−1 of sucrose, 6 g L−1 of Na2HPO4·12H2O, and 50 mg L−1 of atrazine). In addition, a statistically quadratic polynomial mathematical model was suggested (R2 = 0.9873). In contrast to other atrazine-degrading bacteria, ZXY-2 appears to be adapted to life under high salinity conditions and sustains excellent atrazine degradation performance. Therefore it could potentially be applied in atrazine bioremediation.","","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:e6fc3865-531f-4ea9-aeff-e2ef923ae36f","http://resolver.tudelft.nl/uuid:e6fc3865-531f-4ea9-aeff-e2ef923ae36f","Modeling, design and optimization of flapping wings for efficient hovering flighth","Wang, Q. (TU Delft Computational Design and Mechanics)","van Keulen, A. (promotor); Goosen, J.F.L. (copromotor); Delft University of Technology (degree granting institution)","2017","Inspired by insect flights, flapping wing micro air vehicles (FWMAVs) keep attracting attention from the scientific community. One of the design objectives is to reproduce the high power efficiency of insect flight. However, there is no clear answer yet to the question of how to design flapping wings and their kinematics for power-efficient hovering flight. In this thesis, we aim to answer this research question from the perspectives of wing modeling, design and optimization.
Quasi-steady aerodynamic models play an important role in evaluating aerodynamic performance and designing and optimizing flapping wings. In Chapter 2, we present a predictive quasi-steady model by including four aerodynamic loading terms. The loads result from the wing's translation, rotation, their coupling as well as the added-mass effect. The necessity of including all four of these terms in a quasi-steady model to predict both the aerodynamic force and torque is demonstrated. Validations indicate a good accuracy of predicting the center of pressure, the aerodynamic loads and the passive pitching motion for various Reynolds numbers. Moreover, compared to the existing quasi-steady models, the proposed model does not rely on any empirical parameters and, thus, is more predictive, which enables application to the shape and kinematics optimization of flapping wings.
For flapping wings with passive pitching motion, a shift in the pitching axis location alters the aerodynamic loads, which in turn change the passive pitching motion and the flight efficiency. Therefore, in Chapter 3, we investigate the optimal pitching axis location for flapping wings to maximize the power efficiency during hovering flight. Optimization results show that the optimal pitching axis is located between the leading edge and the mid-chord line, which shows a close resemblance to insect wings. An optimal pitching axis can save up to 33% of power during hovering flight when compared to optimized traditional wings used by most of the flapping wing micro air vehicles (FWMAVs). Traditional wings typically use the straight leading edge as the pitching axis. In addition, the optimized pitching axis enables the drive system to recycle more energy during the deceleration phases as compared to their counterparts. This observation underlines the particular importance of the wing pitching axis location for energy-efficient FWMAVs when using kinetic energy recovery drive systems.
The presence of wing twist can alter the aerodynamic performance and power efficiency of flapping wings by changing the angle of attack. In order to study the optimal twist of flapping wings for hovering flight, we propose a computationally efficient fluid-structure interaction (FSI) model in Chapter 4. The model uses an analytical twist model and the quasi-steady aerodynamic model introduced in Chapter 2 for the structural and aerodynamic analysis, respectively. Based on the FSI model, we optimize the twist of a rectangular wing by minimizing the power consumption during hovering flight. The power efficiency of the optimized twistable wings is compared with corresponding optimized rigid wings. It is shown that the optimized twistable wings can not dramatically outperform the optimized rigid wings in terms of power efficiency, unless the pitching amplitude at the wing root is limited. When this amplitude decreases, the optimized twistable wings can always maintain high power efficiency by introducing certain twist while the optimized rigid wings need more power for hovering.
Considering the high impact of the root stiffness on flapping kinematics and power consumption, we present an active hinge design which uses electrostatic force to change the hinge stiffness in Chapter 5. The hinge is realized by stacking three conducting spring steel layers which are separated by dielectric Mylar films. The theoretical model shows that the stacked layers can switch from slipping with respect to each other to sticking together when the resultant electrostatic force between layers, which can be controlled by the applied voltage, is above a threshold value. The switch from slipping to sticking will result in a dramatic increase of the hinge stiffness (about 9x). Therefore, a short duration of the sticking can still lead to a considerable change in the passive pitching motion. Experimental results successfully show the decrease of the pitching amplitude with the increase of the applied voltage. Flight control based on the electrostatic force can be very power-efficient since there is ideally no power consumption due to the control operations.
In Chapter 6, we retrospect and discuss the most important aspects related to the modeling, design and optimization of flapping wings for efficient hovering flight. In Chapter 7, the overall conclusions are drawn and recommendations for further study are provided.","flapping wing; passive pitching; pitching axis; aerodynamic model; power efficiency; optimization","en","doctoral thesis","","978-94-92516-57-2","","","","","","","","","Computational Design and Mechanics","","",""
"uuid:70e42787-9a3f-4f0c-9fed-c1daed7c1794","http://resolver.tudelft.nl/uuid:70e42787-9a3f-4f0c-9fed-c1daed7c1794","Business models for building material circularity: Learnings from frontrunner","Wang, K.; Vanassche, S.; Ribeiro, A.; Peters, M.; Oseyran, J.","","2017","One of the expected key outcomes of the Horizon 2020 BAMB (Buildings As Material Banks) project is new business models for material circularity. The team has interviewed four “frontrunner” cases which have pioneered in incorporating elements of building circularity. The study included well-known cases such as the new Venlo city hall (the Netherlands), PROgroup (Luxembourg), Rotor DC (Belgium) and Karlstad hospital (Sweden), while taking a fresh focus on business aspects such as value propositions, stakeholders, financials and operations. Preliminary analysis suggests that successful circular building projects are devised with a holistic view on various sustainability elements and ecosystem stakeholders. In comparison to more developed building sustainability elements such as energy, material circularity is still rather new in many aspects. Related business models vary significantly in maturity depending on product/material category, overall with ample room for growth. Supplier buyback agreements and product-service systems are being developed, though how to put retrieved items back into the economy, as well as how to establish solid financial cases for involved stakeholders, are among the topics which still need further substantiation. Encouraging advance has been made in deconstruction business models, while more attention is needed to developing second-hand market demand. The potentials of public procurement and regulatory incentives as additional key drivers are also to be further investigated.","case study; circular economy; business model; building materials","en","conference paper","","","","","","","","","","","","","",""
"uuid:ad3f23f8-5bb7-47d1-a42b-bd1043fed661","http://resolver.tudelft.nl/uuid:ad3f23f8-5bb7-47d1-a42b-bd1043fed661","Use of Affordances for Efficient Robot Learning","Wang, C. (TU Delft Interactive Intelligence)","Babuska, R. (promotor); Hindriks, K.V. (copromotor); Delft University of Technology (degree granting institution)","2017","","Robot Learning; Affordance; Reinforcement Learning; Developmental Robotics","en","doctoral thesis","","978-94-6186-814-5","","","","","","","","","Interactive Intelligence","","",""
"uuid:8feebaa3-3dde-4502-b15d-6057127b0bcd","http://resolver.tudelft.nl/uuid:8feebaa3-3dde-4502-b15d-6057127b0bcd","Modeling and Design of Brushless Doubly-Fed Induction Machines","Wang, X. (TU Delft DC systems, Energy conversion & Storage)","Ferreira, Jan Abraham (promotor); Lahaye, D.J.P. (copromotor); Polinder, H. (copromotor); Delft University of Technology (degree granting institution)","2017","The rapid increase of wind power in the power grid results in high grid connection requirements for wind turbines. Moreover, the reliability of wind turbines becomes more and more important, especially in offshore applications. One potential solution for these demands is the wind turbine drive-train based on the brushless doubly-fed induction machine (DFIM). This machine type has no brushes or slip-rings on the rotor side which provides an attractive alternative to the DFIM which is commonly employed in the current market. However, the brushless DFIM has not yet been commercialized. Therefore, the primary objective of this thesis focuses on ‘modeling and design of brushless DFIM, to advance the development of this machine type for wind turbine applications’. A computationally efficient FE model is proposed to evaluate the performance of the brushless DFIM. An efficient, flexible and accurate optimization approach is then developed by combining the computationally efficient FE model with the NSGA-II multi-objective optimization algorithm. Compared with normal induction machines, the brushless DFIM is expected to have more severe noise, vibrations and lower power quality due to many undesired space-harmonics. The 2D multi-slice FE model is applied to investigate whether skewing rotor slots is useful to overcome these drawbacks of brushless DFIMs. Based on the study of the space- and time-harmonics in brushless DFIMs, a computationally efficient method is proposed to investigate the effects of skew at the initial design stage. Sixteen constructions are evaluated to gain more design guidelines for nested-loop rotors. The complicated space- and time-harmonics, the influence of the rotor skew and the influence of the nested-loop configurations are studied and validated by carrying out measurements on a small-scale prototype with four different rotors. The 3D magneto-static FE model is applied to investigate the axial flux due to the skewed slots which is neglected in the 2D multi-slice FE model. Finally, all the modeling methods and the design guidelines are brought together to optimize the design of a 3.2MW brushless DFIM. The results show that the design is improved from the active material cost and the efficiency of the machine points of view by increasing the magnetic loading of the brushless DFIMs. However, the brushless DFIM does not show advantages compared with normal DFIGs and PM generators from the efficiency and the shear stress points of view. However, considering the additional advantages of maintenance and reliability, the brushless DFIMs may provide a feasible application for wind turbine drive-trains.","","en","doctoral thesis","","978-94-6299-625-0","","","","","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:36499b1f-9014-4c1d-9ae2-f6e9c73dbdc8","http://resolver.tudelft.nl/uuid:36499b1f-9014-4c1d-9ae2-f6e9c73dbdc8","Slope failure simulations with MPM","Vardon, P.J. (TU Delft Geo-engineering); Wang, B. (TU Delft Geo-engineering; Chinese Academy of Sciences); Hicks, M.A. (TU Delft Geo-engineering)","","2017","The simulation of slope failures, including both failure initiation and development, has been modelled using the material point method (MPM). Numerical case studies involving various slope angles, heterogeneity and rainfall infiltration are presented. It is demonstrated that, by utilising a constitutive model which encompasses, in a simplified manner, both pre- and post-failure behaviour, the material point method is able to simulate commonly observed failure modes. This is a step towards being able to better quantify slope failure consequence and risk.","Heterogeneity; material point method (MPM); rainfall-induced; slope failure; strain softening","en","journal article","","","","","","","","2019-05-15","","","Geo-engineering","","",""
"uuid:adaebdcc-9919-4d6e-9680-574ddd2ddacf","http://resolver.tudelft.nl/uuid:adaebdcc-9919-4d6e-9680-574ddd2ddacf","The Random Material Point Method","Wang, B. (TU Delft Geo-engineering); Vardon, P.J. (TU Delft Geo-engineering); Hicks, M.A. (TU Delft Geo-engineering)","","2017","The material point method is a finite element variant which allows the material, represented by a point-wise discretization, to move through the background mesh. This means that large deformations, such as those observed post slope failure, can be computed. By coupling this material level discretization to the spatial variability of the material generated by random fields and embedding this into a Monte Carlo framework, a new method called the Random Material Point Method (RMPM) has been developed. This method retains the advantages of the so-called random finite element method, that is, a risk based interpretation of the influence of spatial variability of the material properties, but additionally enables the effective modeling of large deformations to give a risk based interpretation of post-failure mechanisms. After a brief introduction to the RMPM methodology, the analysis of an idealized cohesion strain-softening clay slope is presented, which illustrates the influence of anisotropy of the material variability on the evolution of retrogressive slope failures.","","en","conference paper","","","","","","","","2018-07-01","","","Geo-engineering","","",""
"uuid:1656bbd3-d7d1-4942-919c-e8edc91fa1d5","http://resolver.tudelft.nl/uuid:1656bbd3-d7d1-4942-919c-e8edc91fa1d5","The electrochemical performance of super P carbon black in reversible Li/Na ion uptake","Peng, B. (TU Delft ChemE/Materials for Energy Conversion and Storage; Renmin University of China); Xu, Y. (TU Delft ChemE/Materials for Energy Conversion and Storage); Wang, Xiaoqun (Renmin University of China; Shanghai Jiao Tong University); Shi, Xinghua (National Center for Nanoscience and Technology (NCNST)); Mulder, F.M. (TU Delft ChemE/Materials for Energy Conversion and Storage)","","2017","Super P carbon black (SPCB) has been widely used as a conducting additive in Li/Na ion batteries to improve the electronic conductivity. However, there has not yet been a comprehensive study on its structure and electrochemical properties for Li/Na ion uptake, though it is important to characterize its contribution in any study of active materials that uses this additive in non-negligible amounts. In this article the structure of SPCB has been characterized and a comprehensive study on the electrochemical Li/Na ion uptake capability and reaction mechanisms are reported. SPCB exhibits a considerable lithiation capacity (up to 310 mAh g–1) from the Li ion intercalation in the graphite structure. Sodiation in SPCB undergoes two stages: Na ion intercalation into the layers between the graphene sheets and the Na plating in the pores between the nano-graphitic domains, and a sodiation capacity up to 145 mAh g–1 has been achieved. Moreover, the influence of the type and content of binders on the lithiation and sodiation properties has been investigated. The cycling stability is much enhanced with sodium carboxymethyl cellulose (NaCMC) binder in the electrode and fluoroethylene carbonate (FEC) in the electrolyte; and a higher content of binder improves the Coulombic efficiency during dis-/charge.","Li ion batteries; Na ion batteries; super P carbon black","en","journal article","","","","","","","","2018-04-14","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:a29f1d59-b4a5-4cba-8532-ef95611ef7e7","http://resolver.tudelft.nl/uuid:a29f1d59-b4a5-4cba-8532-ef95611ef7e7","Shape optimization and optimal control for transient heat conduction problems using an isogeometric approach","Wang, Z. (TU Delft Aerospace Structures & Computational Mechanics); Turteltaub, S.R. (TU Delft Aerospace Structures & Computational Mechanics); Abdalla, M.M. (TU Delft Aerospace Structures & Computational Mechanics)","","2017","This work is concerned with the development of a framework to solve shape optimization problems for transient heat conduction problems within the context of isogeometric analysis (IGA). A general objective functional is used to accommodate both shape optimization and passive control problems under transient conditions. An adjoint sensitivity analysis, which accounts for possible discontinuities in the objective functional, is performed analytically and subsequently discretized within the context of IGA. The gradient of the objective functional is used in a descent algorithm to solve optimization problems. Numerical examples are presented to validate and demonstrate the capacity to manage thermal fields under transient conditions.","Adjoint method; Isogeometric analysis; Passive optimal control; Shape optimization; Transient heat conduction","en","journal article","","","","","","","","2019-03-16","","","Aerospace Structures & Computational Mechanics","","",""
"uuid:08a8a81c-c149-4354-a1b5-1812ac0e5902","http://resolver.tudelft.nl/uuid:08a8a81c-c149-4354-a1b5-1812ac0e5902","Mechanisms of hyperconcentrated ßood propagation in a dynamic channel-floodplain system","Li, W. (Zhejiang University); Su, Zhenghua (Zhejiang University); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Deltares); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); de Vriend, H.J. (TU Delft Rivers, Ports, Waterways and Dredging Engineering; Deltares)","","2017","The downstream peak discharge increase during hyperconcentrated floods in the Yellow River has been attributed to bed erosion, roughness reduction and floodplain effects. While great improvements have been made on the nderstandings of the roles of bed erosion and roughness reduction, the effects of floodplain remain poorly understood. Here, as a first step to reveal the floodplain effects, we present a numerical experimental study on how the channel-floodplain system reacts to a hyperconcentrated flood process. For this purpose, schematized channel-floodplain systems are designed and the classical 1992 flood record data is prescribed at the upstream boundary. By applying a fully coupled morphodynamic model, numerical experiments are conducted for a comprehensive analysis on the effects of bed erodibility, floodplain width, bed roughness variation, symmetry and longitudinal variability of geomorphology. Our results show two distinct trends for the response of channel- floodplain system depending on bed erodibility. For a small bed erodibility, both channel and floodplain experience erosion. For a moderate/large bed erodibility, only the channel experiences erosion whereas deposition occurs on the floodplain. The variation of the floodplain width does not affect these erosion-deposition behaviors while changing the magnitude and patterns of floodplain deposition. The
longitudinally discontinuous channel-floodplain divided by either water storage areas or housing/farming banks diminishes the floodplain deposition at the discontinuous locations. The present numerical experiments do not show an obvious peak discharge increase, nonetheless, the recognized erosion-deposition characteristics would help further study of the floodplain effects on the peak of hyperconcentrated floods.","Hyperconcentrated flood;; floodplain effects; channel-floodplain system; coupled morphodynamic model; peak discharge; Yellow River","en","journal article","","","","","","","","2019-06-01","","","Environmental Fluid Mechanics","","",""
"uuid:efc38f3f-d528-401f-940d-c6e53e9579c9","http://resolver.tudelft.nl/uuid:efc38f3f-d528-401f-940d-c6e53e9579c9","Life cycle assessment in wastewater treatment:: Influence of site-oriented normalization factors, life cycle impact assessment methods, and weighting methods","Bai, Shunwen (Harbin Institute of Technology); Wang, Xiuheng (Harbin Institute of Technology); Zhang, X. (TU Delft Sanitary Engineering); Zhao, Xinyue (Harbin Institute of Technology); Ren, Nanqi (Harbin Institute of Technology)","","2017","This present study aims to analyze the differences in results of different site-directional life cycle assessment
(LCA) methods applied in the field of wastewater treatment. Site-generic methods were employed and
compared with China-specific methods on a full-scale wastewater treatment case. A set of Chinese
normalized factors were developed and employed to compare with world normalization factors. No
substantial discrepancies in results were obtained from the two different sets of normalization factors. In
the phase of life cycle impact assessment, the e-Balance showed substantial discrepancies in results,
compared with the CML method that is widely applied in LCA. The discrepancies were mainly attributed
to the cause that in e-Balance more emphasis is on regional water pollution potential (that is: chemical
oxygen demand (COD) as an independent impact category). Moreover, discrepancies in the results were
also investigated by applying different site-directional weighting methods. Besides the specific locations
where the weighting methods were designed for, this study showed that employing different
environmental indicators in impact categories was another important factor that resulted in differences
in the LCA results of the different weighting methods.","","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:d3ca3b7d-7ce1-46d8-b525-b9465354de75","http://resolver.tudelft.nl/uuid:d3ca3b7d-7ce1-46d8-b525-b9465354de75","Fractal analysis of urban catchments and their representation in semi-distributed models: Imperviousness and sewer system","Gires, Auguste (École des Ponts); Tchiguirinskaia, Ioulia (École des Ponts); Schertzer, Daniel (École des Ponts); Ochoa Rodriguez, S. (Imperial College London); Willems, Patrick (Katholieke Universiteit Leuven); Ichiba, Abdellah (École des Ponts; Conseil Départemental du Val-de-Marne); Wang, L. (Katholieke Universiteit Leuven); Pina, Rui (Imperial College London); Van Assel, Johan (Aquafin NV); Bruni, G. (TU Delft Sanitary Engineering); Murla Tuyls, Damian (Katholieke Universiteit Leuven); ten Veldhuis, Marie-claire (TU Delft Water Resources)","","2017","Fractal analysis relies on scale invariance and the concept of fractal dimension enables one to characterize and quantify the space filled by a geometrical set exhibiting complex and tortuous patterns. Fractal tools have been widely used in hydrology but seldom in the specific context of urban hydrology. In this paper, fractal tools are used to analyse surface and sewer data from 10 urban or peri-urban catchments located in five European countries. The aim was to characterize urban catchment properties accounting for the complexity and inhomogeneity typical of urban water systems. Sewer system density and imperviousness (roads or buildings), represented in rasterized maps of 2m × 2m pixels, were analysed to quantify their fractal dimension, characteristic of scaling invariance. The results showed that both sewer density and imperviousness exhibit scale-invariant features and can be characterized with the help of fractal dimensions ranging from 1.6 to 2, depending on the catchment. In a given area consistent results were found for the two geometrical features, yielding a robust and innovative way of quantifying the level of urbanization. The representation of imperviousness in operational semi-distributed hydrological models for these catchments was also investigated by computing fractal dimensions of the geometrical sets made up of the sub-catchments with coefficients of imperviousness greater than a range of thresholds. It enables one to quantify how well spatial structures of imperviousness were represented in the urban hydrological models.","","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:cf0113e3-b540-45d1-9968-f358a0224e1c","http://resolver.tudelft.nl/uuid:cf0113e3-b540-45d1-9968-f358a0224e1c","High-Density Microporous Li4Ti5O12 Microbars with Superior Rate Performance for Lithium-Ion Batteries","Tang, Linkai (Tsinghua University); He, Yan Bing (Tsinghua University); Wang, Chao (Tsinghua University); Wang, Shuan (Tsinghua University); Wagemaker, M. (TU Delft RST/Fundamental Aspects of Materials and Energy); Li, Baohua (Tsinghua University); Yang, Quan Hong (Tsinghua University); Kang, Feiyu (Tsinghua University)","","2017","Nanosized Li4Ti5O12 (LTO) materials enabling high rate performance suffer from a large specific surface area and low tap density lowering the cycle life and practical energy density. Microsized LTO materials have high density which generally compromises their rate capability. Aiming at combining the favorable nano and micro size properties, a facile method to synthesize LTO microbars with micropores created by ammonium bicarbonate (NH4HCO3) as a template is presented. The compact LTO microbars are in situ grown by spinel LTO nanocrystals. The as-prepared LTO microbars have a very small specific surface area (6.11 m2 g−1) combined with a high ionic conductivity (5.53 × 10−12 cm−2 s−1) and large tap densities (1.20 g cm−3), responsible for their exceptionally stable long-term cyclic performance and superior rate properties. The specific capacity reaches 141.0 and 129.3 mAh g−1 at the current rate of 10 and 30 C, respectively. The capacity retention is as high as 94.0% and 83.3% after 500 and 1000 cycles at 10 C. This work demonstrates that, in situ creating micropores in microsized LTO using NH4HCO3 not only facilitates a high LTO tap density, to enhance the volumetric energy density, but also provides abundant Li-ion transportation channels enabling high rate performance.","high tap densities; Li-ion batteries; lithium titanate; microporous microbars; NHHCO templates","en","journal article","","","","","","","","","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:a5262f80-249f-4a66-9dbf-280c5c60a678","http://resolver.tudelft.nl/uuid:a5262f80-249f-4a66-9dbf-280c5c60a678","Improving estimates of water resources in a semi-arid region by assimilating GRACE data into the PCR-GLOBWB hydrological model","Tangdamrongsub, N. (TU Delft Physical and Space Geodesy; The University of Newcastle, Australia); Steele-Dunne, S.C. (TU Delft Water Resources); Gunter, B.C. (TU Delft Physical and Space Geodesy; Georgia Institute of Technology); Ditmar, P.G. (TU Delft Physical and Space Geodesy); Sutanudjaja, Edwin H. (Universiteit Utrecht); Sun, Y. (TU Delft Laboratory Geoscience and Remote Sensing); Xia, Ting (Tsinghua University); Wang, Zhongjing (Tsinghua University)","","2017","An accurate estimation of water resources dynamics is crucial for proper management of both agriculture and the local ecology, particularly in semi-arid regions. Imperfections in model physics, uncertainties in model land parameters and meteorological data, as well as the human impact on land changes often limit the accuracy of hydrological models in estimating water storages. To mitigate this problem, this study investigated the assimilation of terrestrial water storage variation (TWSV) estimates derived from the Gravity Recovery And Climate Experiment (GRACE) data using an ensemble Kalman filter (EnKF) approach. The region considered was the Hexi Corridor in northern China. The hydrological model used for the analysis was PCR-GLOBWB, driven by satellite-based forcing data from April 2002 to December 2010. The impact of the GRACE data assimilation (DA) scheme was evaluated in terms of the TWSV, as well as the variation of individual hydrological storage estimates. The capability of GRACE DA to adjust the storage level was apparent not only for the entire TWSV but also for the groundwater component. In this study, spatially correlated errors in GRACE data were taken into account, utilizing the full error variance-covariance matrices provided as a part of the GRACE data product. The benefits of this approach were demonstrated by comparing the EnKF results obtained with and without taking into account error correlations. The results were validated against in situ groundwater data from five well sites. On average, the experiments showed that GRACE DA improved the accuracy of groundwater storage estimates by as much as 25 %. The inclusion of error correlations provided an equal or greater improvement in the estimates. In contrast, a validation against in situ streamflow data from two river gauges showed no significant benefits of GRACE DA. This is likely due to the limited spatial and temporal resolution of GRACE observations. Finally, results of the GRACE DA study were used to assess the status of water resources over the Hexi Corridor over the considered 9-year time interval. Areally averaged values revealed that TWS, soil moisture, and groundwater storages over the region decreased with an average rate of approximately 0.2, 0.1, and 0.1 cm yr-1 in terms of equivalent water heights, respectively. A particularly rapid decline in TWS (approximately -0.4 cm yr-1) was seen over the Shiyang River basin located in the southeastern part of Hexi Corridor. The reduction mostly occurred in the groundwater layer. An investigation of the relationship between water resources and agricultural activities suggested that groundwater consumption required to maintain crop yield in the growing season for this specific basin was likely the cause of the groundwater depletion.","","en","journal article","","","","","","","","","","","Physical and Space Geodesy","","",""
"uuid:e786ee1f-8fea-4ef2-a67b-08fad87ae0f1","http://resolver.tudelft.nl/uuid:e786ee1f-8fea-4ef2-a67b-08fad87ae0f1","Multiple-site damage crack growth behaviour in Fibre Metal Laminate structures","Wang, W. (TU Delft Structural Integrity & Composites)","Benedictus, R. (promotor); Rans, C.D. (copromotor); Delft University of Technology (degree granting institution)","2017","Fibre metal laminates (FMLs)were developed and refined for their superior crack growth resistance and critical damage size that complimented the damage tolerance design philosophy utilized in the aerospace sector. Robust damage tolerance tools have been developed for FMLs. However, they tend to focus on the evolution of an isolated crack. There is also a risk that they will be invalidated overtime as a result of the occurrence of multiple cracks within one structure (one form of widespread fatigue damage). To combat another failure due to widespread fatigue damage, the airworthiness regulations were revised to include the concept of a Limit of Validity (LOV) of the damage tolerance analyses. Consequently, it is crucial to examine fatigue crack growth (FCG) in FMLs containing Multiple-site Damage (MSD) cracks despite their superior damage tolerance merits. The focus of this thesis therefore is to analyse MSD crack growth in FML structures. Mechanically fastened FML joints are potentially weak structural designs that are susceptible to MSD due to the stress rising contributors such as secondary bending, pin loading and open holes subjected to bypass loading. In this thesis, predictive models were developed to address several key mechanisms that affect FCG in FML joints containing MSD, and validated with corresponding experimental work. Then the predictive models were systematically integrated and implemented for FML joints. It was identified that the nature of fatigue in FMLs led to the load redistribution mechanism as the key factor to be modelled in predicting MSD growth in FMLs. The structural stiffness reductions caused by the presence of multiple cracks resulted in load redistribution from the other cracks to the single crack to be analysed, exacerbating the total stress intensity factor (SIF) experienced at the tips of the single crack, increasing the crack growth rate (CGR). The load redistribution mechanism was first substantiated by investigating FCG in FMLs containing discretely notched layers. The prediction model fairly captured the load redistribution mechanism by idealizing the notches in the metal layers as removals of metal strips. The crack acceleration over a major portion of the crack propagation was well predicted with the model; however, the surge in CGR over roughly 3 mm crack length prior to the link-up was underestimated since the plasticity interaction was not accounted for. The capability of modelling the load redistribution mechanism allows the states of multiple cracks to be analysed one by one. It was found that the load redistribution could not be symmetric for every crack and non-symmetric crack configurations therefore developed in FMLs with finite width. Hence, non-symmetric crack growth in FMLs was also investigated in this work. It was also found that both crack tip non-symmetry and delamination shape non-symmetry affected the crack growth in the metal layers. The model for non-symmetric crack growth in FMLs was validated with experimental data. Good correlation was observed. The model for MSD growth in FML panels sequentially analyses each crack state. The other cracks are idealized as removals of metal strips when analyzing the state of a single crack. This non-physical idealization of the cracks led to consistently conservative prediction results in comparison with the test data. Nevertheless, the prediction model provided good predictions of the evolution of MSD configurations. Additionally, it was proven that a very non-conservative predicted fatigue life could be obtained if the load redistribution mechanism was not considered. The effects of pin loading on FCG in FMLs were also investigated. The test data showed very rapid growth of the crack in the vicinity of the pin loading. The CGR decreased with increasing crack length. The model applied the principle of superposition to split the non-symmetric tension-pin loading into simpler tensile loading and a pair of point loads acting on the crack flanks. The SIFs for the simpler loading cases were derived and superposed to obtain the total SIF as a result of the tension-pin loading. The predicted CGR and equivalent delamination shape correlated with the measurements very well, but the model failed to predict the crack path and the measured delamination shape which were trivial issues for this work. The relevance and applicability of the developed models in this thesis for predicting the MSD behaviour in mechanically fastened FML joints was examined. The predicted results captured the trends of the measured CGR in FML joints containing MSD cracks, although there were some discrepancies. The discrepancies are mainly due to the two major shortcomings of the model which are neglecting the load redistribution over multiple fastener rows and neglecting the effects of secondary bending stresses.","Fatigue Crack Growth; fibre metal laminates; Multiple site damage; load redistribution","en","doctoral thesis","","978-94-6295-642-1","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:45d21ed5-a841-453e-9150-090b4d2b10b7","http://resolver.tudelft.nl/uuid:45d21ed5-a841-453e-9150-090b4d2b10b7","SPM response to tide and river flow in the hyper-turbid Ems River","Winterwerp, J.C. (TU Delft Environmental Fluid Mechanics; Deltares); Vroom, J (Deltares); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); Krebs, Martin (EMS Waterway Administration); Hendriks, H.C.M. (TU Delft Environmental Fluid Mechanics); van Maren, D.S. (TU Delft Environmental Fluid Mechanics; Deltares); Schrottke, Kerstin (University of Kiel); Borgsmüller, Christine (Federal Institute of Hydrology); Schöl, Andreas (Federal Institute of Hydrology)","","2017","In this paper, we analyse the behaviour of fine sediments in the hyper-turbid Lower Ems River, with focus on the river’s upper reaches, a stretch of about 25 km up-estuary of Terborg. Our analysis is based on long records of suspended particulate matter (SPM) from optical backscatter (OBS) measurements close to the bed at seven stations along the river, records of salinity and water level measurements at these stations, acoustic measurements on the vertical mud structure just up-estuary of Terborg and oxygen profiles in the lower 3 m of the water column close to Leerort and Terborg. Further, we use cross-sectionally averaged velocities computed with a calibrated numerical model. Distinction is made between four timescales, i.e. the semi-diurnal tidal timescale, the spring–neap tidal timescale, a timescale around an isolated peak in river flow (i.e. about 3 weeks) and a seasonal timescale. The
data suggest that a pool of fluid/soft mud is present in these upper reaches, from up-estuary of Papenburg to a bit downestuary
of Terborg. Between Terborg and Gandersum, SPM values drop rapidly but remain high at a few gram per litre. The pool of fluid/soft mud is entrained/mobilized at the onset of flood, yielding SPM values of many tens gram per litre. This suspension is transported up-estuary with the flood. Around high water slack, part of the suspension settles, being remixed during ebb, while migrating down-estuary, but likely not much further than Terborg. Around low water slack, a large fraction of the sediment settles, reforming the pool of fluid mud. The rapid entrainment from the fluid mud layer after low water slack is only possible when the peak flood velocity exceeds a critical value of around 1 m/s, i.e. when the stratified water column seems to become internally supercritical. If the peak flood velocity does not reach this critical value, f.i. during neap tide, fluid mud is not entrained up to the OBS sensors. Thus, it is not classical tidal asymmetry, but the peak flood velocity itself which governs the hyper-turbid state
in the Lower Ems River. The crucial role of river flow and river floods is in reducing these peak flood velocities. During elongated periods of high river flow, in e.g. wintertime, SPM concentrations reduce, and the soft mud deposits consolidate and possibly become locally armoured aswell by sand washed in from the river. We have no observations that sediments are washed out of the hyper-turbid zone. Down-estuary of Terborg, where SPM values do not reach hyper-turbid conditions, the SPMdynamics are governed by classical tidal asymmetry and estuarine circulation. Hence, nowhere in the river, sediments are flushed from the upper reaches of the river into the Ems-Dollard estuary during high river flow events. However, exchange of sediment between river and estuary should occur because of tide-induced dispersion.","Tidal asymmetry; Hyper-turbid sediment","en","journal article","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:f474528a-6150-4370-a28a-ead96a99e795","http://resolver.tudelft.nl/uuid:f474528a-6150-4370-a28a-ead96a99e795","Thermospheric recovery during the 5 April 2010 geomagnetic storm","Sheng, Cheng (The Earth and Sun Systems Laboratory); Lu, Gang (The Earth and Sun Systems Laboratory); Solomon, Stanley C. (The Earth and Sun Systems Laboratory); Wang, Wenbin (The Earth and Sun Systems Laboratory); Doornbos, E.N. (TU Delft Astrodynamics & Space Missions); Hunt, Linda A. (NASA Langley Research Center); Mlynczak, Martin G. (NASA Langley Research Center)","","2017","Thermospheric temperature and density recovery during the 5 April 2010 geomagnetic storm has been investigated in this study. Neutral density recovery as revealed by Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM) simulations was slower than observations from GOCE, CHAMP, and GRACE satellites, suggesting that the cooling processes may not be fully represented in the model. The NO radiative cooling rate in TIEGCM was also compared with TIMED/SABER measurements along satellite orbits during this storm period. It was found that the model overestimated the NO cooling rate at low latitudes and underestimated it at high latitudes. The effects of particle precipitation on NO number density and NO cooling rate at high latitudes were examined in detail. Model experiments showed that while NO number density and NO cooling rate do change with different specifications of the characteristic energy of auroral precipitating electrons, neutral temperature and density recovery remain more or less the same. The reaction rates of key NO chemistry were tested as well, and the NO number density between 110 and 150 km was found to be very sensitive to the reaction rate of N(2D) + O2 → NO + O. A temperature-dependent reaction rate for this reaction proposed by Duff et al. (2003) brought the TIEGCM NO cooling rate at high latitudes closer to the SABER observations. With the temperature-dependent reaction rate, the neutral density recovery time became quite close to the observations in the high-latitude Southern Hemisphere. But model-data discrepancies still exist at low latitudes and in the Northern Hemisphere, which calls for further investigation.","neutral density; NO cooling; particle precipitation; thermospheric recovery","en","journal article","","","","","","","","2017-10-01","","","Astrodynamics & Space Missions","","",""
"uuid:a345fd42-53c1-4ff9-a154-f0d08e8fb868","http://resolver.tudelft.nl/uuid:a345fd42-53c1-4ff9-a154-f0d08e8fb868","Peroxygenases en route to becoming dream catalysts. What are the opportunities and challenges?","Wang, Yonghua (South China University of Technology); Lan, Dongming (South China University of Technology); Durrani, Rabia (South China University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis)","","2017","Peroxygenases are promising catalysts for preparative oxyfunctionalization chemistry as they combine the versatility of P450 monooxygenases with simplicity of cofactor-independent enzymes. Though many interesting applications have been reported, today ‘we have only scratched the surface’ and significant efforts are necessary to solve issues related to selectivity of the wild type enzymes and low product titers. For this, further elucidation of the vast natural diversity as well as protein and reaction engineering approaches are discussed.","","en","review","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:f7d8f441-53a6-4210-ac3d-0fb6609cb9f5","http://resolver.tudelft.nl/uuid:f7d8f441-53a6-4210-ac3d-0fb6609cb9f5","Chitosan cross-linked poly(acrylic acid) hydrogels: drug release control and mechanism","Wang, Y. (TU Delft ChemE/Advanced Soft Matter; East China University of Science and Technology); Wang, Jie (East China University of Science and Technology); Yuan, Z. (East China University of Science and Technology); Han, Haoya (East China University of Science and Technology; Technical University of Berlin); Li, Tao (East China University of Science and Technology); Li, Li (East China University of Science and Technology); Guo, Xuhong (East China University of Science and Technology; Shihezi University)","","2017","Chitosan has been used to cross-link poly(acrylic acid) to give three pH-sensitive hydrogels designed to control the release of the drugs amoxicillin and meloxicam. The extent of cross-linking and solution pH was found to dominate the swelling behavior of these hydrogels as shown by scanning electron microscopy and swelling time dependencies. The rates of release of amoxicillin and meloxicam from the loaded hydrogels increased with increase in pH consistent with the extent of hydrogen bonding between hydrogel components and between the hydrogel and the drugs being important determinants of release rate. Both the Korsemeyer-Peppas and Weibull models fitted release data consistent with drug release occurred through a combination of drug diffusion and hydrogel relaxation processes. These hydrogels appear to provide an ideal basis for controlled drug delivery systems.","Chitosan; Drug delivery; pH sensitive hydrogel; Release mechanism","en","journal article","","","","","","Accepted Author Manuscript","","2019-01-21","","","ChemE/Advanced Soft Matter","","",""
"uuid:3a73bfe7-1b5e-4099-939b-8e4c38172690","http://resolver.tudelft.nl/uuid:3a73bfe7-1b5e-4099-939b-8e4c38172690","Reaction Mechanism Study of the Di-Air System and Selectivity and Reactivity of NO Reduction in Excess O2","Makkee, M. (TU Delft ChemE/Catalysis Engineering); Wang, Y. (TU Delft ChemE/Catalysis Engineering)","","2017","We studied the mechanism of NO reduction as well as its selectivity and reactivity in the presence of excess O2. Results show that fuel injection and/or pretreatment are important for ceria catalyst reduction and carbon deposition on the catalyst surface. Oxygen defects of reduced ceria are the key sites for the reduction of NO into N2. The deposited carbon acts as a buffer reductant, i.e., the oxidation of carbon by lattice oxygen recreates oxygen defects to extend the NO reduction time interval. A small amount of NO showed a full conversion into only N2 both on the reduced Zr-La doped ceria and reduced Pt-Zr-La doped ceria. Only when the catalyst is oxidised NO is converted into NO2.","","en","journal article","","","","","","","","2017-09-28","","","ChemE/Catalysis Engineering","","",""
"uuid:48239759-6d0c-4aea-a203-a1313270040c","http://resolver.tudelft.nl/uuid:48239759-6d0c-4aea-a203-a1313270040c","Engineering a lipase B from Candida antactica with efficient perhydrolysis performance by eliminating its hydrolase activity","Wang, Xu Ping (South China University of Technology); Zhou, Peng Fei (South China University of Technology); Li, Zhi Gang (South China University of Technology); Yang, Bo (South China University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Yong Hua (South China University of Technology)","","2017","A Ser105Ala mutant of the lipase B from Candida antarctica enables 'perhydrolase-only' reactions. At the example of the chemoenzymatic Baeyer-Villiger oxidation of cyclohexanone, we demonstrate that with this mutant selective oxidation can be achieved in deep eutectic solvent while essentially eliminating the undesired hydrolysis reaction of the product.","","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:c8ac51cf-26b8-4a8f-a48d-dbe419e9f7aa","http://resolver.tudelft.nl/uuid:c8ac51cf-26b8-4a8f-a48d-dbe419e9f7aa","Deep Eutectic Solvents Enable More Robust Chemoenzymatic Epoxidation Reactions","Zhou, Pengfei (South China University of Technology); Wang, Xuping (South China University of Technology); Zeng, Chaoxi (South China University of Technology); Wang, Weifei (South China University of Technology); Yang, Bo (South China University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Yonghua (South China University of Technology)","","2017","A chemoenzymatic method for the production of epoxidized vegetable oils was developed. The unique combination of the commercial lipase G from Penicillieum camembertii with certain deep eutectic solvents enabled the efficient production of epoxidized vegetable oils.","chemoenzymatic synthesis; deep eutectic solvents; enzymes; epoxidation; fatty acids","en","journal article","","","","","","Accepted Author Manuscript","","2017-12-25","","","BT/Biocatalysis","","",""
"uuid:f531a003-492d-444e-b8ee-eae7f9fccd6a","http://resolver.tudelft.nl/uuid:f531a003-492d-444e-b8ee-eae7f9fccd6a","In-operation field-of-view retrieval (IFR) for satellite and ground-based DOAS-type instruments applying coincident high-resolution imager data","Sihler, Holger (Max Planck Institute of Chemistry; University of Heidelberg); Lübcke, Peter (University of Heidelberg); Lang, Rüdiger (European Organisation for the Exploitation of Meteorological Satellites); Beirle, Steffen (Max Planck Institute of Chemistry); de Graaf, M. (TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI)); Hörmann, Christoph (Max Planck Institute of Chemistry); Lampel, Johannes (Max Planck Institute of Chemistry); Penning de Vries, Marloes (Max Planck Institute of Chemistry); Remmers, Julia (Max Planck Institute of Chemistry); Trollope, Ed (European Organisation for the Exploitation of Meteorological Satellites; Telespazio VEGA Deutschland); Wang, Yang (Max Planck Institute of Chemistry); Wagner, Thomas (Max Planck Institute of Chemistry)","","2017","Knowledge of the field of view (FOV) of a remote sensing instrument is particularly important when interpreting their data and merging them with other spatially referenced data. Especially for instruments in space, information on the actual FOV, which may change during operation, may be difficult to obtain. Also, the FOV of ground-based devices may change during transportation to the field site, where appropriate equipment for the FOV determination may be unavailable.
This paper presents an independent, simple and robust method to retrieve the FOV of an instrument during operation, i.e. the two-dimensional sensitivity distribution, sampled on a discrete grid. The method relies on correlated measurements featuring a significantly higher spatial resolution, e.g. by an imaging instrument accompanying a spectrometer. The method was applied to two satellite instruments, GOME-2 and OMI, and a ground-based differential optical absorption spectroscopy (DOAS) instrument integrated in an SO2 camera. For GOME-2, quadrangular FOVs could be retrieved, which almost perfectly match the provided FOV edges after applying a correction for spatial aliasing inherent to GOME-type instruments. More complex sensitivity distributions were found at certain scanner angles, which are probably caused by degradation of the moving parts within the instrument. For OMI, which does not feature any moving parts, retrieved sensitivity distributions were much smoother compared to GOME-2. A 2-D super-Gaussian with six parameters was found to be an appropriate model to describe the retrieved OMI FOV. The comparison with operationally provided FOV dimensions revealed small differences, which could be mostly explained by the limitations of our IFR implementation. For the ground-based DOAS instrument, the FOV retrieved using SO2-camera data was slightly smaller than the flat-disc distribution, which is assumed by the state-of-the-art correlation technique. Differences between both methods may be attributed to spatial inhomogeneities.
In general, our results confirm the already deduced FOV distributions of OMI, GOME-2, and the ground-based DOAS. It is certainly applicable for degradation monitoring and verification exercises. For satellite instruments, the gained information is expected to increase the accuracy of combined products, where measurements of different instruments are integrated, e.g. mapping of high-resolution cloud information, incorporation of surface climatologies. For the SO2-camera community, the method presents a new and efficient tool to monitor the DOAS FOV in the field.","Satellite imagery","en","journal article","","","","","","","","","","","Atmospheric Remote Sensing","","",""
"uuid:e6062c8a-d04c-4e16-a3ec-a2a1eea9ee3a","http://resolver.tudelft.nl/uuid:e6062c8a-d04c-4e16-a3ec-a2a1eea9ee3a","Assessment of Water Use in Pan-Eurasian and African Continents by ETMonitor with Multi-Source Satellite Data","Zheng, Chaolei (Chinese Academy of Sciences); Jia, L. (TU Delft Optical and Laser Remote Sensing; Chinese Academy of Sciences); Hu, Guangcheng (Chinese Academy of Sciences); Menenti, M. (TU Delft Optical and Laser Remote Sensing; Chinese Academy of Sciences); Lu, Jing (Chinese Academy of Sciences); Zhou, J. (TU Delft Optical and Laser Remote Sensing; Chinese Academy of Sciences); Wang, Kun (Chinese Academy of Sciences); Li, Zhansheng (Chinese Academy of Sciences)","","2017","The Pan-Eurasian and African Continents are characterized by large ranges of climates varying from humid, semi-humid, semi-arid and arid regions, and great challenges exist in water allocation for different sectors that related to water resource and food security, which depends strongly on the water use information. Quantitative information on water use is also important to understand the effectiveness of water allocation and further to prevent from water stress resulted by drought in water-scarce regions. Explosive development of satellite remote sensing observations provide great chance to provide useful spatiotemporal information for quantifying the water use at regional to global scales. In this paper, a process-based model ETMonitor was used in combination with biophysical and hydrological parameters retrieved from earth observations to estimate the actual evapotranspiration, i.e. the agricultural and ecological water use. The total water use is also partitioned into beneficial part, e.g. plant transpiration, and non-beneficial part, e.g. soil evaporation and canopy rainfall interception, according to the water accounting framework. The estimated water use show good agreements with the ground observation, indicating the ability of ETMonitor for global and continental scale water use estimation. The spatial and temporal patterns of the water use in the Pan-Eurasian and African Continents were further analysed, while large spatial variation of water use was convinced. Current study also highlights the great capability of satellite observations in studying the regional water resource and continental water cycle.","","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:0c3a6c7d-5a68-46dc-8683-dc8d47bbbdf8","http://resolver.tudelft.nl/uuid:0c3a6c7d-5a68-46dc-8683-dc8d47bbbdf8","Simultaneous photocatalytic and microbial degradation of dye-containing wastewater by a novel g-C3 N4 -P25 /photosynthetic bacteria composite","Zhang, Xinying (Fuzhou University); Wu, Yan (Fuzhou University); Xiao, Gao (Fuzhou University); Tang, Zhenping (Fuzhou University); Wang, Meiyin (Fuzhou University); Liu, Fuchang (Fuzhou University); Zhu, X. (TU Delft Sanitary Engineering)","","2017","Azo dyes are very resistant to light-induced fading and biodegradation. Existing advanced oxidative pre-treatment methods based on the generation of non-selective radicals cannot efficiently remove these dyes from wastewater streams, and post-treatment oxidative dye removal is problematic because it may leave many byproducts with unknown toxicity profiles in the outgoing water, or cause expensive complete mineralization. These problems could potentially be overcome by combining photocatalysis and biodegradation. A novel visiblelight-responsive hybrid dye removal agent featuring both photocatalysts (g-C3 N4 -P25 ) and photosynthetic bacteria encapsulated in calcium alginate beads was prepared by selfassembly. This system achieved a removal efficiency of 94% for the dye reactive brilliant red X-3b and also reduced the COD of synthetic wastewater samples by 84.7%, successfully decolorized synthetic dye-contaminated wastewater and reduced its COD, demonstrating the advantages of combining photocatalysis and biocatalysis for wastewater purification. The composite apparently degrades X-3b by initially converting the dye into aniline and phenol derivatives whose aryl moieties are then attacked by free radicals to form alkyl derivatives, preventing the accumulation of aromatic hydrocarbons that might suppress microbial activity. These alkyl intermediates are finally degraded by the photosynthetic bacteria.","","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:e31f5f47-fca7-42de-810b-c8f2dd9c7516","http://resolver.tudelft.nl/uuid:e31f5f47-fca7-42de-810b-c8f2dd9c7516","Real-time volumetric lipid imaging in vivo by intravascular photoacoustics at 20 frames per second","Wu, Min (Erasmus MC); Springeling, Geert (Erasmus MC); Lovrak, M. (TU Delft ChemE/Advanced Soft Matter); Mastik, Frits (Erasmus MC); Iskander-Rizk, Sophinese (Erasmus MC); Wang, Tianshi (Erasmus MC); Van Beusekom, Heleen M.M. (Erasmus MC); van der Steen, A.F.W. (TU Delft ImPhys/Acoustical Wavefield Imaging; Erasmus MC; Chinese Academy of Sciences); van Soest, G. (Erasmus MC)","","2017","Lipid deposition can be assessed with combined intravascular photoacoustic/ultrasound (IVPA/US) imaging. To date, the clinical translation of IVPA/US imaging has been stalled by a low imaging speed and catheter complexity. In this paper, we demonstrate imaging of lipid targets in swine coronary arteries in vivo, at a clinically useful frame rate of 20 s−1. We confirmed image contrast for atherosclerotic plaque in human samples ex vivo. The system is on a mobile platform and provides real-time data visualization during acquisition. We achieved an IVPA signal-to-noise ratio of 20 dB. These data show that clinical translation of IVPA is possible in principle.","Imaging systems; Photoacoustic imaging","en","journal article","","","","","","","","","","","ChemE/Advanced Soft Matter","","",""
"uuid:f24a64b0-ef93-42d7-81a0-a5d34a4eb3dc","http://resolver.tudelft.nl/uuid:f24a64b0-ef93-42d7-81a0-a5d34a4eb3dc","Slope failure analysis using the material point method","Wang, B. (TU Delft Geo-engineering)","Hicks, M.A. (promotor); Vardon, P.J. (copromotor); Delft University of Technology (degree granting institution)","2017","","Heterogeneity; Implicit dynamics; Large deformation; Material point method; rainfall; Slope failure","en","doctoral thesis","","","","","","","","","","","Geo-engineering","","",""
"uuid:ee9a218a-a3bb-49a3-bed4-0ab62dbe4f7b","http://resolver.tudelft.nl/uuid:ee9a218a-a3bb-49a3-bed4-0ab62dbe4f7b","The differences in morphological development between the intertidal flats of the Eastern and Western Scheldt","de Vet, P.L.M. (TU Delft Environmental Fluid Mechanics); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Wang, Zhengbing (TU Delft Coastal Engineering)","","2017","Human interventions have a large impact on estuarine morphology. The intertidal flats in the Eastern Scheldt and Western Scheldt estuaries (The Netherlands) have faced substantial morphological changes over the past decades. These changes are thought to be caused by human interventions, such as the construction of the storm surge barrier in the mouth of the Eastern Scheldt, and the deepening of the navigation channels of the Western Scheldt. This paper analyses several datasets and numerical simulations of hydrodynamics, providing an overview of the various morphological characteristics of the intertidal flats in the two estuaries over time and space. Apart from the volume, area and average height of these areas, also the integral steepness of each flat is quantified based on its full geometry. The analyses focus on the intertidal flats surrounded by water, which allows for a robust comparison between the different flats. The intertidal flats in the Western Scheldt appear to be substantially steeper compared to those in the Eastern Scheldt. The data indicates that a larger average height of a flat is related to a larger steepness. Despite variations in the evolution of the different flats, distinct characteristics of both estuaries are observed. An opposed trend is identified over time: the flats in the Western Scheldt have mainly increased in height, whereas the flats in the Eastern Scheldt have lowered after the completion of the storm surge barrier. This opposing development is associated with differences in tidal flow velocities in the estuaries, which are the result of human interventions.","Eastern Scheldt; Western Scheldt; human interventions; intertidal flats","en","journal article","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:2237917b-06ca-41e8-9cfc-0666448abb32","http://resolver.tudelft.nl/uuid:2237917b-06ca-41e8-9cfc-0666448abb32","Improved numerical solution of Drobovol'skaya's boundary integral equations on similarity flow for uniform symmetrical entry of wedges","Wang, Jingbo; Faltinsen, Odd M.","","2017","","hydrodynamics","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:615c14a4-2bc4-4db2-9ce1-558acc870e16","http://resolver.tudelft.nl/uuid:615c14a4-2bc4-4db2-9ce1-558acc870e16","Interaction between allogenic and autogenic forcing in the fluvial successions, Wyoming, Bighorn Basin, USA","Wang, Y.","","2017","Autogenic and allogenic forcing interacts at different timescales, and their interaction results in the sequential sedimentary patterns observed in fluvial sediment records (Abels et al., 2013). Field studies help to understand surface processes in the past and interpret the way fluvial architecture is formed. That is crucial for geological modeling of subsurface basin fill. However, it is not easy to differentiate autogenic forcing from allogenic, because of their overlapping temporal and spatial scales and the influence of allogenic factors on autogenic ones (Bridge, 2003; Stouthamer & Berendsen, 2007). In my project, I study this interaction by using numerical forward modeling tied to field data. In 2017, using a Molengraaff grant, I have been able to document high-detail excellent fluvial outcrops in the Bighorn Basin, Wyoming, using drone- based photogrammetry. Based on these data and combined numerical modelling work, I would like to report my progress in the last year.","","en","report","Delft University of Technology","","","","","","","","","","","","Molengraaff Fonds",""
"uuid:93684f02-85e3-4773-bd72-5c07987967c2","http://resolver.tudelft.nl/uuid:93684f02-85e3-4773-bd72-5c07987967c2","Path Planning for First Responders in the Presence of Moving Obstacles With Uncertain Boundaries","Wang, Z. (TU Delft Interactive Intelligence); Zlatanova, S. (TU Delft Urban Data Science); van Oosterom, P.J.M. (TU Delft OLD Department of GIS Technology)","","2017","In this paper, we study path planning for first responders in the presence of uncertain moving obstacles. To support the path planning, in our research we use hazard simulation to provide the predicted information of moving obstacles. A major problem in using hazard simulation is that the simulation results may involve uncertainty due to model errors or noise in the real measurements. To address this problem, we provide an approach to handle the uncertainty in the information of moving obstacles, and apply it to the case of toxic plumes. Our contribution consists of two parts: 1) a spatial data model that supports the representation of uncertain obstacles from hazard simulations and their influence on the road network and 2) a modified A* algorithm that can deal with the uncertainty and generate fast and safe routes passing though the obstacles. The experimental results show the routing capability of our approach and its potential for the application to real disasters.","data model; route planning; algorithm; uncertain moving obstacles","en","journal article","","","","","","Accepted Author Manuscript","","","","","Interactive Intelligence","","",""
"uuid:930306ea-d477-4132-a76c-a086521629b0","http://resolver.tudelft.nl/uuid:930306ea-d477-4132-a76c-a086521629b0","Comparative assessment of safety indicators for vehicle trajectories on the highway","Mullakkal-Babu, F.A. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); Farah, H. (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning); Happee, R. (TU Delft Intelligent Vehicles)","","2017","Safety measurement and analysis have been a challenging and well-researched topic in transportation. Conventionally, surrogate safety measures have been used as safety indicators in simulation models for safety assessment, in control formulations for driver assistance systems, and in data analysis of naturalistic driving studies. However, surrogate indicators only give partial insights into traffic safety i.e., they only indicate a predetermined set of possible pre-crash situations for an interacting vehicle pair. Recently, a safety indicator called the driving safety field based on field theory has been proposed for two-dimensional vehicle interactions. However, the objectivity of its functional form and validity are yet to be tested. This paper provides a qualitative and quantitative comparison of different safety indicators as a risk measure to demarcate their mathematical properties and evaluate their usefulness in quantifying trajectory risk. We compare five relevant safety indicators: inverse time to collision, post-encroachment time, potential indicator of collision with urgent decceleration, warning index and safety field strength. Their formulations are mathematically analyzed to yield qualitative insights and their values over simulated vehicle trajectories are evaluated to yield quantitative insights. Our results acknowledge the limitations and demarcate the functional utilities of the selected safety indicators.","Driver support systems; Highway safety; Mathematical methods; risk assessment; Traffic simulation; Vehicle trajectories; Time to collision; Surrogate safety indicators; Risk measure; Safety field force; Automated Driving","en","conference paper","Transportation Research Board (TRB)","","","","","Report/Paper Numbers: 17-04210","","","","Transport and Planning","Transport and Planning","","",""
"uuid:af6e0c1c-6379-4fb1-9d9d-4e9c189a7d05","http://resolver.tudelft.nl/uuid:af6e0c1c-6379-4fb1-9d9d-4e9c189a7d05","Nanoemulsion-induced enzymatic crosslinking of tyramine-functionalized polymer droplets","Kamperman, T. (University of Twente); Henke, S. (University of Twente); Zoetebier, B. (University of Twente); Ruiterkamp, N. (University of Twente); Wang, R. (University of Twente; Universiteit Maastricht); Pouran, B. (TU Delft Biomaterials & Tissue Biomechanics; Universiteit Utrecht); Weinans, Harrie (TU Delft Biomaterials & Tissue Biomechanics; Universiteit Utrecht); Karperien, M. (University of Twente); Leijten, J (University of Twente)","","2017","In situ gelation of water-in-oil polymer emulsions is a key method to produce hydrogel particles. Although this approach is in principle ideal for encapsulating bioactive components such as cells, the oil phase can interfere with straightforward presentation of crosslinker molecules. Several approaches have been developed to induce in-emulsion gelation by exploiting the triggered generation or release of crosslinker molecules. However, these methods typically rely on photo- or acid-based reactions that are detrimental to cell survival and functioning. In this work, we demonstrate the diffusion-based supplementation of small molecules for the in-emulsion gelation of multiple tyramine-functionalized polymers via enzymatic crosslinking using a H2O2/oil nanoemulsion. This strategy is compatible with various emulsification techniques, thereby readily supporting the formation of monodisperse hydrogel particles spanning multiple length scales ranging from the nano- to the millimeter. As proof of principle, we leveraged droplet microfluidics in combination with the cytocompatible nature of enzymatic crosslinking to engineer hollow cell-laden hydrogel microcapsules that support the formation of viable and functional 3D microtissues. The straightforward, universal, and cytocompatible nature of nanoemulsion-induced enzymatic crosslinking facilitates its rapid and widespread use in numerous food, pharma, and life science applications.","","en","journal article","","","","","","","","2018-05-02","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:27cff6a2-2b8e-4969-a781-facf17e386f9","http://resolver.tudelft.nl/uuid:27cff6a2-2b8e-4969-a781-facf17e386f9","The variations of sediment transport patterns in the outer Changjiang Estuary and Hangzhou Bay over the last 30 years","Xie, DF (Zhejiang Institute of Hydraulics and Estuary); Pan, CH (Zhejiang Institute of Hydraulics and Estuary); Wu, Xiuguang (Zhejiang Institute of Hydraulics and Estuary); Gao, S (East China Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2017","The research objective is to investigate the variations of sediment transport in outer Changjiang Estuary and adjacent Hangzhou Bay, induced by the decline of Changjiang River sediment discharge and massive land reclamation in the last three decades. A synchronous hydrographic survey was conducted along two transects (at the bay-mouth and outer Changjiang Estuary, respectively) during the spring-neap tides of January and July 2014. The results show that the suspended sediment grain size, current velocity, suspended sediment concentration (SSC), and the water and sediment fluxes varied with the tidal cycles. Quantitative correlations with the tidal range were found for SSC and fluxes. These data have been compared with those at the same hydrographic stations in the summer and winter of the early 1980s. Along the outer Changjiang Estuary transect, the SSCs and sediment fluxes decreased in the winter, but no apparent changes occurred in the summer. The SSCs in the northern Hangzhou Bay decreased in both summer and winter, while the southern bay mouth has evolved from a low SSC region to a high SSC region. The findings clarify that the SSC and sediment flux changes in this area have only an indirect connection to the dramatic riverine sediment decline, because the sediment resuspension by the strong tidal currents provided a major source. At the present stage, the impact of the riverine sediment decline is insignificant for the SSC variation off the Changjiang River mouth. Finally, a sediment flux model is proposed to explain and predict the morphological evolution trends.","","en","journal article","","","","","","","","2017-11-01","","","Coastal Engineering","","",""
"uuid:40e6a41f-757e-4960-be47-7d4bdb179804","http://resolver.tudelft.nl/uuid:40e6a41f-757e-4960-be47-7d4bdb179804","Comparison of Nested-Loop Rotors in Brushless Doubly-Fed Induction Machines","Wang, X. (TU Delft DC systems, Energy conversion & Storage); Liu, D. (TU Delft DC systems, Energy conversion & Storage); Lahaye, D.J.P. (TU Delft Numerical Analysis); Polinder, H. (TU Delft DC systems, Energy conversion & Storage); Ferreira, Jan Abraham (TU Delft Electrical Power Processing)","","2017","The brushless doubly-fed induction machine (DFIM) has great potential as a variable-speed generator for wind turbine applications. This special machine has a richer space-harmonic spectrum due to its special nested-loop rotor construction compared with conventional induction machines. It may result in higher iron losses, higher torque ripple and more time-harmonics adding to the grid total harmonic distortion (THD). This paper applies the 2D finite element (FE) model to investigate several different nested loop rotor constructions. It shows the outer loop makes more contribution to the torque while the inner loop plays a small role in the torque production. The most outer loop determines the overall THD level while the inner one has little influence on it. The THD could be reduced by increasing the number of the outer loops. More machine performances could be studied to derive more guidelines for designing the
middle loops.","permanent magnet machine; Concentrated winding; eddy current losses; experimental validation","en","conference paper","IEEE","","","","","","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:073519a2-5585-4fe7-9c7d-547e3fd7d39e","http://resolver.tudelft.nl/uuid:073519a2-5585-4fe7-9c7d-547e3fd7d39e","Exploratory morphodynamic hindcast of the evolution of the abandoned Yellow River delta, 1578-1855","Su, M. (TU Delft Coastal Engineering; Sun Yat-sen University; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering); Yao, P. (TU Delft Coastal Engineering; Sun Yat-sen University; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares; Hohai University); Zhang, C.K. (Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering); Stive, M.J.F. (TU Delft Coastal Engineering)","","2017","The Abandoned Yellow River Delta (AYD), which formed when the Yellow River flowed into the Southern Yellow Sea between 1128 and 1855 AD, is a representative example of the sensitivity of deltas to modifications in their environments. In this study, we established a process-based morphodynamic model to explore the morphological evolution of one such largescale fine-grained delta (the AYD before 1855). The uncertainties in the model settings, which are inevitable when historical data are insufficient, were assessed together with the corresponding influences on the evolution of the deltaic system by considering a series of scenarios. The results indicate that the strength of local tidal forcing is the key factor that determines the shape and evolutionary trend of the delta. Sediment input discharge and the slope of the initial coastal profile have a considerable effect on the overall size of the delta and the relative ratio between subaerial and subaqueous parts of the delta, respectively. Based on the evaluation of the uncertainties and a comparison with historical maps, the simulated AYD was evaluated to be reliable. Through an analysis of the temporal delta evolution and residual sediment transport, the morphological evolution of the AYD before 1855 AD was investigated. The southern delta grew as the shoals merged with the mainland, which is in agreement with an existing hypothesis (Zhang, 1984), whereas the accretion of the northern delta was independent from the shoals in the northern part. Additionally, suggestions are made regarding the distribution of the AYD at the end of its progradation stage, which provides fundamental information for analyzing subsequent erosion processes since 1855 AD. This study differs from existing studies on the AYD, which are all based on geological approaches. It provides insight into the evolution of the AYD through an alternative means, viz. a process-based morphodynamic-modeling approach.","","en","journal article","","","","","","","","2018-12-31","","","Coastal Engineering","","",""
"uuid:abed2a22-5306-4a5f-8d3e-bd412b3aa150","http://resolver.tudelft.nl/uuid:abed2a22-5306-4a5f-8d3e-bd412b3aa150","Gust Load Alleviation and Ride Quality Improvement with Incremental Nonlinear Dynamic Inversion","Wang, X.; van Kampen, E. (TU Delft Control & Simulation); Chu, Q. P. (TU Delft Control & Simulation)","","2017","","","en","conference paper","American Institute of Aeronautics and Astronautics Inc. (AIAA)","","","","","","","2018-01-06","","","Control & Simulation","","",""
"uuid:0cb3a6df-e1c8-41c4-b2e0-cbf8c475ca3a","http://resolver.tudelft.nl/uuid:0cb3a6df-e1c8-41c4-b2e0-cbf8c475ca3a","Policy Gaming for Humanitarian Missions","Schwarz, P. (TU Delft Policy Analysis); Wang, Y. (TU Delft Policy Analysis); Lukosch, S.G. (TU Delft System Engineering); Lukosch, H.K. (TU Delft Policy Analysis)","","2017","Aid workers increasingly face risks when working in crisis regions. In order to improve effectiveness and safety
of humanitarians, it is of great importance to provide a well thought out real-time socio-technical support. Thus,
new policies and innovative technological solutions need to be developed and integrated into humanitarian
workflows. For the requirements elicitation process to realize this aspiration, we employ a board game approach
that confronts players with situations aid workers experience in the field. From the first game session, we
learned that the game is a valuable tool. It raises awareness to important challenges and trade-offs that
humanitarians face. In addition, it is an effective catalyst for initiating a discussion on which system
requirements are needed. Future work will include an update of the board game as well as sessions with the
target group of practitioners to inform the development of a socio-technical system for humanitarian aid work.","","en","conference paper","","","","","","","","","","","Policy Analysis","","",""
"uuid:f65ccf95-b122-4565-ab3e-3ccf274c19a9","http://resolver.tudelft.nl/uuid:f65ccf95-b122-4565-ab3e-3ccf274c19a9","An efficient fluid–structure interaction model for optimizing twistable flapping wings","Wang, Q. (TU Delft Computational Design and Mechanics); Goosen, J.F.L. (TU Delft Computational Design and Mechanics); van Keulen, A. (TU Delft Computational Design and Mechanics)","","2017","Spanwise twist can dominate the deformation of flapping wings and alters the aerodynamic performance and power efficiency of flapping wings by changing the local angle of attack. Traditional Fluid–Structure Interaction (FSI) models, based on Computational Structural Dynamics (CSD) and Computational Fluid Dynamics (CFD), have been used to investigate the influence of twist on the power efficiency. However, it is impractical to use them for twist optimization due to the high computational cost. On the other hand, it is of great interest to study the optimal twist of flapping wings. In this work, we propose a computationally efficient FSI model based on an analytical twist model and a quasi-steady aerodynamic model which replace the expensive CSD and CFD methods. The twist model uses a polynomial to describe the change of the twist angle along the span. The polynomial order is determined based on a convergence study. A nonlinear plate model is used to evaluate the structural response of the twisted wing. The adopted quasi-steady aerodynamic model analytically calculates the aerodynamic loads by including four loading terms which originate from the wing's translation, rotation, their coupling and the added-mass effect. Based on the proposed FSI model, we optimize the twist of a rectangular wing by minimizing the power consumption during hovering flight. The power efficiency of optimized twistable and rigid wings is studied. Comparisons indicate that the optimized twistable wings exhibit power efficiencies close to the optimized rigid wings, unless the pitching amplitude at the wing root is limited. When the pitching amplitude at the root decreases by increasing the root stiffness, the optimized rigid wings need more power for hovering. However, with the help of wing twist, the power efficiencies of optimized twistable wings with a prescribed root stiffness are comparable with the twistable wings with an optimal root stiffness. This observation provides an explanation for the different levels of twist exhibited by insect wings. The high computational efficiency of the proposed FSI model allows further application to parametric studies and optimization of flapping wings. This will enhance the understanding of insect wing flexibility and help the design of flexible artificial wings for flapping wing micro air vehicles.","Fluid–structure interaction; Hovering flight; Optimization; Power efficiency; Twistable flapping wing","en","journal article","","","","","","Accepted Author Manuscript","","2019-06-20","","","Computational Design and Mechanics","","",""
"uuid:8b35a6d0-001e-46ca-acc6-7c6874b6c5d6","http://resolver.tudelft.nl/uuid:8b35a6d0-001e-46ca-acc6-7c6874b6c5d6","Renal transplant patient acceptance of a self-management support system","Wang, W. (TU Delft Interactive Intelligence; TNO); van Lint, Celine L. (Leiden University Medical Center); Brinkman, W.P. (TU Delft Interactive Intelligence); Rövekamp, Ton J.M. (TNO); van Dijk, Sandra (Leiden University Medical Center); van der Boog, Paul J.M. (Leiden University Medical Center); Neerincx, M.A. (TU Delft Interactive Intelligence; TNO)","","2017","Background
Self-management support systems (SMSS) have been proposed for renal transplant patients to increase their autonomy and reduce the number of hospital visits. For the design and implementation of such systems, it is important to understand factors influencing patients’ acceptance of a SMSS. This paper aims to identify these key factors.
Methods
From literature, possible factors and related questionnaire items were identified. Afterwards, focus groups with experts and patients were conducted to adapt the items to the application domain. To investigate acceptance of a SMSS and the influencing factors, fifty renal transplant patients answered the questionnaire before and after using the SMSS for 4 months.
Results
All the questionnaire constructs had a satisfactory or higher level of reliability. After using the SMSS for 4 months, trust and performance expectancy could explain part of the variation in behavioural intention of using the SMSS, but not beyond the explanation given by patients’ affect towards the system, which accounted for 26% of the variance.
Conclusions
We anticipate that in future caregivers implementing a SMSS will benefit from taking steps to improve patients’ affect as this was found to correlate with patients use intention.
Trial registration
The study was registered in ToetsingOnline, a registry held by the Dutch Central Committee on Research Involving Human Subjects. The registration number is NL33387.058.11, and the date of registration is 31st July 2012.
based on their physical meanings and correlations. It outputs an integrated indicator of catenary condition level. The BN parameters are learned from historical measurement data. Preliminary results shows the applicable ability of the BN to integrate multiple types of parameter while make sense of the output to facilitate maintenance decision making.","","en","conference paper","","","","","","","","","","","Railway Engineering","","",""
"uuid:376bdfef-a9fd-421c-b456-ab1e27d85960","http://resolver.tudelft.nl/uuid:376bdfef-a9fd-421c-b456-ab1e27d85960","UAV: Warnings From Multiple Automated Static Analysis Tools At A Glance","Buckers, Tim (External organisation); Cao, Clinton (External organisation); Doesburg, Michiel (External organisation); Gong, Boning (External organisation); Wang, Sunwei (External organisation); Beller, M.M. (TU Delft Software Engineering); Zaidman, A.E. (TU Delft Software Engineering)","Pinzger, Martin (editor); Bavota, Gabriele (editor); Marcus, Andrian (editor)","2017","Automated Static Analysis Tools (ASATs) are an integral part of today’s software quality assurance practices. At present, a plethora of ASATs exist, each with different strengths. However, there is little guidance for developers on which of these ASATs to choose and combine for a project. As a result, many projects still only employ one ASAT with practically no customization. With UAV, the Unified ASAT Visualizer, we created an intuitive visualization that enables developers, researchers, and tool creators to compare the complementary strengths and overlaps of different Java ASATs. UAV’s enriched treemap and source code views provide its users with a seamless exploration of the warning distribution from a high-level overview down to the source code. We have evaluated our UAV prototype in a user study with ten second-year Computer Science (CS) students, a visualization expert and tested it on large Java repositories with several thousands of PMD, FindBugs, and Checkstyle warnings.
Project Website: https://clintoncao.github.io/uav","Visualization; Java; Data visualization; Color; Navigation; Btowsers; Libraries","en","conference paper","IEEE","","","","","","","","","","Software Engineering","","",""
"uuid:a46d4243-739e-488d-b237-8cfbe05cbdc6","http://resolver.tudelft.nl/uuid:a46d4243-739e-488d-b237-8cfbe05cbdc6","Behind the Scenes of Scenario-Based Training: Understanding Scenario Design and Requirements in High-Risk and Uncertain Environments","Noori, Nadia Saad (University of Agder); Wang, Y. (TU Delft Policy Analysis); Comes, M. (University of Agder); Lukosch, H.K. (TU Delft Policy Analysis)","","2017","Simulation exercises as a training tool for enhancing preparedness for emergency response are widely adopted in disaster management. This paper addresses current scenario design processes, proposes an alternative approach for simulation exercises and introduces a conceptual design of an adaptive scenario generator. Our work is based on a systematic literature review and observations made during TRIPLEX-2016 exercise in Farsund, Norway. The planning process and scenario selection of simulation exercises impact directly the effectiveness of intra- and interorganizational cooperation. However, collective learning goals are rarely addressed and most simulations are focused on institution-specific learning goals. Current scenario design processes are often inflexible and begin from scratch for each exercise. In our approach, we address both individual and collective learning goals and the demand to develop scenarios on different layers of organizational learning. Further, we propose a scenario generator that partly automates the scenario selection and adaptively responds to the exercise evolvement.","Humanitarian simulation exercise; scenario design process; collective learning; interorganizational coordination","en","conference paper","","","","","","","","","","","Policy Analysis","","",""
"uuid:fe221324-9382-4c58-90ec-f70b7806094b","http://resolver.tudelft.nl/uuid:fe221324-9382-4c58-90ec-f70b7806094b","Performance analysis of double-effect absorption heat pump cycle using NH3/ILs pairs","Wang, M. (TU Delft Engineering Thermodynamics); Infante Ferreira, C.A. (TU Delft Engineering Thermodynamics)","","2017","Ionic liquids (ILs), as novel absorbents, draw considerable attention for their potential roles in replacing H2O or LiBr aqueous solutions in conventional NH3/H2O or H2O/LiBr absorption chiller or heat pump cycles. In this paper, NH3/IL working pairs are proposed for implementation in parallel double effect heat pump systems. To investigate their performance, a property-prediction method, based on experimental heat capacities and the nonrandom two-liquid (NRTL) activity coefficient model for the vapor pressure, was used to estimate the thermodynamic properties for the proposed NH3/IL mixtures. Then, parallel configuration double-effect absorption heat pump cycles driven by a high-temperature heat source were analyzed by means of evaluation of the thermodynamic operating limits and performance simulations with the aforementioned properties. The ILs investigated include [Mmim][DMP], [Emim][BF4], [Hmim][BF4], [Omim][BF4], [Bmim][BF4], [Bmim][PF6], [Emim][Tf2N], [Emim][EtSO4] and [Emim][SCN]. The performance, such as the coefficient of performance, COP, and circulation ratio f, along with the environmental temperature used as heat source were compared for these ILs based pairs and the conventional ones. This work on double-effect heat pumps with NH3/ILs pairs shows that there is an optimum distribution ratio between the parallel flows and that some of the investigated mixtures have the potential to show a better performance than that of the traditional NH3/H2O pair in cooling and heating applications.
3/ionic liquid mixtures for absorption heat pump cycles","Kabra, Abhishek; Becker, T. (TU Delft Engineering Thermodynamics); Wang, M. (TU Delft Engineering Thermodynamics); Infante Ferreira, C.A. (TU Delft Engineering Thermodynamics); Vlugt, T.J.H. (TU Delft Engineering Thermodynamics)","","2017","Force Field based Monte Carlo (MC) simulations are conducted to predict the performance of an absorption heat pump cycle involving NH3/ionic liquid (IL) (refrigerant/absorbent) as working pair. To investigate the thermodynamic performance of the cycle, various properties such as the enthalpy of absorption, heat capacity, and solubility of refrigerant in the absorbent are required. As an alternative to experiments, MC simulations are used to predict the required properties. The simulations are performed at temperatures ranging from 303 K to 373 K and pressures ranging from 4 to 16 bar. The thermodynamic performance parameters such as the coefficient of performance, COP, and the circulation ratio, f, of NH3 paired with [emim][Tf2N] are investigated using MC simulations and compared to results obtained from correlated experimental data, showing a reasonable agreement. MC simulations could be used as an inexpensive alternative for preliminary design considerations involving potential working pairs for absorption heat pump cycles in the absence of available experimental data.","Working pair; Absorption cycle; Monte Carlo simulations; Heat pump; Ionic liquids; NH3","en","conference paper","Stichting HPC 2017","","","","","","","","","","Engineering Thermodynamics","","",""
"uuid:3ee8a6c3-01a7-4232-add9-d8d75ef5f3a6","http://resolver.tudelft.nl/uuid:3ee8a6c3-01a7-4232-add9-d8d75ef5f3a6","Self-Monitoring Kidney Function Post Transplantation: Reliability of Patient-Reported Data","van Lint, Céline (Leiden University Medical Center); Wang, W. (TU Delft Interactive Intelligence); van Dijk, Sandra (Universiteit Leiden); Brinkman, W.P. (TU Delft Interactive Intelligence); Rövekamp, Ton J.M. (TNO); Neerincx, M.A. (TU Delft Interactive Intelligence; TNO); Rabelink, Ton J. (Leiden University Medical Center); van der Boog, Paul J.M. (Leiden University Medical Center)","","2017","Background: The high frequency of outpatient visits after kidney transplantation is burdensome to both the recovering patient and health care capacity. Self-monitoring kidney function offers a promising strategy to reduce the number of these outpatient visits. Objective: The objective of this study was to investigate whether it is safe to rely on patients’ self-measurements of creatinine and blood pressure, using data from a self-management randomized controlled trial. Methods: For self-monitoring creatinine, each participant received a StatSensor Xpress-i Creatinine Meter and related test material. For self-monitoring blood pressure, each participant received a Microlife WatchBP Home, an oscillometric device for blood pressure self-measurement on the upper arm. Both devices had a memory function and the option to download stored values to a computer. During the first year post transplantation, 54 patients registered their self-measured creatinine values in a Web-based Self-Management Support System (SMSS) which provided automatic feedback on the registered values (eg, seek contact with hospital). Values registered in the SMSS were compared with those logged automatically in the creatinine device to study reliability of registered data. Adherence to measurement frequency was determined by comparing the number of requested with the number of performed measurements. To study adherence to provided feedback, SMSS-logged feedback and information from the electronic hospital files were analyzed. Results: Level of adherence was highest during months 2-4 post transplantation with over 90% (42/47) of patients performing at least 75% of the requested measurements. Overall, 87.00% (3448/3963) of all registered creatinine values were entered correctly, although values were often registered several days later. If (the number of) measured and registered values deviated, the mean of registered creatinine values was significantly lower than what was measured, suggesting active selection of lower creatinine values. Adherence to SMSS feedback ranged from 53% (14/24) to 85% (33/39), depending on the specific feedback. Conclusions: Patients’ tendency to postpone registration and to select lower creatinine values for registration and the suboptimal adherence to the feedback provided by the SMSS might challenge safety. This should be well considered when designing self-monitoring care systems, for example by ensuring that self-measured data are transferred automatically to an SMSS.","Creatinine; Data accuracy; Kidney transplantation; Patient compliance; Patient reported outcomes; Self-care","en","journal article","","","","","","","","","","","Interactive Intelligence","","",""
"uuid:e50f6817-8e95-49db-b6e9-590fa571e547","http://resolver.tudelft.nl/uuid:e50f6817-8e95-49db-b6e9-590fa571e547","EasySRRobot: An Easy-to-Build Self-Reconfigurable Robot with Optimized Design","Yu, Minjing (Tsinghua University); Liu, Yong-Jin (Tsinghua University); Wang, C.C. (TU Delft Materials and Manufacturing)","","2017","Self-reconfigurable modular robots (SRRobot) that can change their shape and function in different environments according to different tasks have caught a lot of attention recently. Most existing prototypes use professional electronic components with relatively expensive cost and high barrier of fabrication. In this paper, we present a low-cost SRRobot with double-cube modules. Our system is easy-to-build even for novices as all electric components are off-the-shelf and the structural components in plastics are made by 3D printing. To have a better design of interior structures, we first construct a design space for all feasible solutions that satisfy the constraints of fabrication. Then, an optimized solution is found by an objective function incorporating the factors of space utilization, structural sound-ness and assembly complexity. Thirty EasySRRobot modules are manufactured and assembled. The functionality of our algorithm is demonstrated by comparing an optimized interior design with other two feasible designs and realizing different motions on an EasySRRobot with four modules.","self-reconfiguration; modular robot; optimal design","en","conference paper","IEEE","","","","","Accepted author manuscript","","","","","Materials and Manufacturing","","",""
"uuid:09192ff6-c894-4862-9ce8-999c9b84f3e6","http://resolver.tudelft.nl/uuid:09192ff6-c894-4862-9ce8-999c9b84f3e6","Potential impact of methyl isobutyl ketone (MIBK) on phenols degradation in an UASB reactor and its degradation properties","Wang, Wei (Hefei University of Technology); Yang, Kai (Hefei University of Technology); Muñoz Sierra, Julian (TU Delft Sanitary Engineering); Zhang, X. (TU Delft Sanitary Engineering); Yuan, Shoujun (Hefei University of Technology); Hu, Zhenhu (Hefei University of Technology)","","2017","Methyl isobutyl ketone (MIBK) as a solvent is extensively used for the phenols extraction from the wastewater, so it is unavoidable to expose in the effluent due to the solubility and leakage problem. The present study evaluated the impact of MIBK on phenols degradation in an UASB reactor and analyzed its degradation properties. The results indicated that the continuous dosing (0.1 g L−1) and impact (10 g L−1) of MIBK had limited effect on phenols removal (1–2% reduction) in the UASB reactor, but the specific methanogenic activity (SMA) values of sludge decreased by 45–75% after MIBK exposure. Anaerobic degradation rate of MIBK fitted well to a pseudo-first-order kinetic equation with respect to the initial concentration of 35 mg L−1 (k = 0.0115 h−1, R2 = 0.9664). Furthermore, the relative methane generation rate constants of MIBK were 0.00816, 0.00613, 0.00273, and 0.00207 d−1 at the initial concentrations of 0.1, 0.5, 5, and 10 g L−1, respectively. MIBK showed higher inhibitory effect on the methanogenesis than on phenols degradation. This study pointed out that the industrial installations should consider the influence of solvent on anaerobic treatment of phenolic wastewater.","Methyl isobutyl ketone; Phenolic compounds; Solvent; Specific methanogenic activity; UASB","en","journal article","","","","","","","","2019-03-22","","","Sanitary Engineering","","",""
"uuid:d0ee96bf-1b65-45d3-964b-1b41d3a23758","http://resolver.tudelft.nl/uuid:d0ee96bf-1b65-45d3-964b-1b41d3a23758","Estuarine morphodynamic adaptation to sediment supply and human activities: A case study of turbidity maximum","Zhu, C. (TU Delft Coastal Engineering; East China Normal Univeristy); Guo, L (East China Normal University); Tian, B. (East China Normal University); He, Q (East China Normal University); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)","","2017","Estuarine morphodynamics undergo significant changes due to declined sediment supply from river, rising sea-level, and human interferences (Syvitski and Saito, 2007; Syvitski et al., 2009). The Yangtze Estuary is such a case whose decadal morphodynamic evolution was broadly examined. It was documented that the subaqueous delta shifted from deposition to erosion since the early 2000s due to sediment supply reduction after the Three Gorges Dam (Yang et al., 2015) while some others reported that the estuary mouth bar area sustains accretion until 2010 (Luan et al., 2016; Zhu et al., 2016). The mouth bar area of the Yangtze Estuary is where the turbidity maximum exists. To clarify the morphodynamic changes therein, we examine the two large scale shoals, i.e. the Hengsha flat and the Jiuduan shoal, based on bathymetric data between 1958 and 2016 and satellite images since 1985.","","en","abstract","","","","","","","","","","","Coastal Engineering","","",""
"uuid:1f46cc50-c3e6-425c-91bb-d05944301420","http://resolver.tudelft.nl/uuid:1f46cc50-c3e6-425c-91bb-d05944301420","Kemeny's constant and the effective graph resistance","Wang, X. (TU Delft Mathematical Physics); Dubbeldam, J.L.A. (TU Delft Mathematical Physics); Van Mieghem, P.F.A. (TU Delft Network Architectures and Services)","","2017","Kemeny's constant and its relation to the effective graph resistance has been established for regular graphs by Palacios et al. [1]. Based on the Moore–Penrose pseudo-inverse of the Laplacian matrix, we derive a new closed-form formula and deduce upper and lower bounds for the Kemeny constant. Furthermore, we generalize the relation between the Kemeny constant and the effective graph resistance for a general connected, undirected graph.","Effective graph resistance or Kirchhoff index; Kemeny constant; Moore–Penrose pseudo-inverse; Multiplicative degree-Kirchhoff index; Spectral graph theory","en","journal article","","","","","","Accepted Author Manuscript","","2019-09-22","","","Mathematical Physics","","",""
"uuid:97aa86b5-691d-447e-bfe2-23ae0821263c","http://resolver.tudelft.nl/uuid:97aa86b5-691d-447e-bfe2-23ae0821263c","Research on conditional characteristics vision real-time detection system for conveyor belt longitudinal tear","Qiao, Tiezhu (Taiyuan University of Technology); Li, Xinyu (Taiyuan University of Technology); Pang, Y. (TU Delft Transport Engineering and Logistics); Lü, Yuxiang (Taiyuan University of Technology); Wang, Feng (Taiyuan University of Technology); Jin, Baoquan (Taiyuan University of Technology)","","2017","Conveyor belt longitudinal tear is one of the most serious problems in coal mining. Existing systems cannot realise lossless and real-time detection for longitudinal tear of conveyor belt. Currently, visual detecting systems are proposed by many researchers and are becoming the future trend. A visual recognition system based on using laser and area light sources is designed in this study, which can recognise and count abrasions, incomplete-tears, and complete-tears. The advantage of the system is to prevent longitudinal tear based on multi-feature information. In the process of detecting conditional characteristics, laser and area light sources are responsible for enhancing contrast between conditional features and conveyor belt surface, meanwhile false corner filtration and single-point feature identification method are designed for improving recognition accuracy of the system. Compared with several current systems, the designed system has a better performance on recognising complex tear characteristics of conveyor belt, thus the problem of starting warning only based on single feature can be effectively avoided.","belts; coal; conveyors; mining equipment; real-time systems","en","journal article","","","","","","Accepted Author Manuscript","","","","","Transport Engineering and Logistics","","",""
"uuid:8e6820e6-7443-48f7-8c8c-80fd43e480b4","http://resolver.tudelft.nl/uuid:8e6820e6-7443-48f7-8c8c-80fd43e480b4","Study on route division for ship energy efficiency optimization based on big environment data","Wang, K. (Wuhan University of Technology); Yan, Xinping (National Engineering Research Center for Water Transport Safety (WTSC)); Yuan, Yupeng (Wuhan University of Technology); Jiang, X. (TU Delft Transport Engineering and Logistics); Lodewijks, G. (TU Delft Transport Engineering and Logistics); Negenborn, R.R. (TU Delft Transport Engineering and Logistics)","Ma, Weiming (editor)","2017","In the case of the global energy crisis and the higher sound of energy saving and emission reduction, how to take effective management measures of ship energy efficiency to achieve the goal of energy saving and emission reduction, put forward a new challenge for the development of shipping technology. The application of big data technology provides a new idea for the research of ship energy efficiency optimization management. The energy efficiency management level of the operating ship can be improved by the analysis and mining of the big data. In this paper, a big data analysis platform for ship energy efficiency management based on the widely used Hadoop platform architecture is designed. Afterward, due to the huge amount of involved data on the energy efficiency management which has exceeded the processing ability of traditional solutions, the big data analysis method is used to achieve the route division according to environmental factors, thus to lay the foundation for speed optimization in different segments of a route. Finally, a simple decision-making method of optimal engine speed based on the result of route division is proposed, which could improve ship energy efficiency and hence reduce CO2 emission.","Marine vehicles; Big Data; Energy efficiency; Optimization; Environmental factors; Navigation; Algorithm design and analysis","en","conference paper","IEEE","","","","","Accepted Author Manuscript","","","","","Transport Engineering and Logistics","","",""
"uuid:1cceb732-d169-4388-8018-c5427f219fd7","http://resolver.tudelft.nl/uuid:1cceb732-d169-4388-8018-c5427f219fd7","Cross section-based hollowing and structural enhancement","Wang, Weiming (Dalian University of Technology); Li, Baojun (Dalian University of Technology); Qian, Sicheng (Dalian University of Technology); Liu, Yong-Jin (Tsinghua University); Wang, C.C. (TU Delft Materials and Manufacturing); Liu, Ligang (University of Science and Technology of China); Yin, Baocai (Dalian University of Technology); Liu, Xiuping (Dalian University of Technology)","","2017","Recently, 3D printing has become a powerful tool for personal fabrication. However, the price of some materials is still high which limits its applications in home users. To optimize the volume of the model, while not largely affecting the strength of the objects, researchers propose algorithms to divide the model with different kinds of lightweight structures, such as frame structure, honeycomb cell structure, truss structure, medial axis tree. However, these algorithms are not suitable for the model whose internal space needs to be reused. In addition, the structural strength and static stability of the models, obtained with modern 3D model acquirement methods, are not guaranteed. In consequence, some models are too fragile to print and cannot be survived in daily usage, handling, and transportation or cannot stand in a stable. To handle the mentioned problems, an algorithm system is proposed based on cross sections in this work. The structural weak cross sections are enhanced, and structural strong cross sections are adaptively hollowed to meet a given structural strength, static stability, printability, etc., while the material usage is minimized. The proposed algorithm system has been tested on several typical 3D models. The experimental results demonstrate the effectiveness and practicability of our system.","3D printing; Adaptive hollowing; Cross section; Structural enhancement","en","journal article","","","","","","Author Accepted Manuscript","","2018-05-16","","","Materials and Manufacturing","","",""
"uuid:4ffef8f8-5ca3-4a47-a321-933a23ee0282","http://resolver.tudelft.nl/uuid:4ffef8f8-5ca3-4a47-a321-933a23ee0282","A Coflow-based Co-optimization Framework for High-performance Data Analytics","Cheng, Long (Eindhoven University of Technology); Wang, Ying (Chinese Academy of Sciences); Pei, Yulong (Eindhoven University of Technology); Epema, D.H.J. (TU Delft Dataintensive Systems)","","2017","Efficient execution of distributed database operators such as joining and aggregating is critical for the performance of big data analytics. With the increase of the compute speedup of modern CPUs, reducing the network
communication time of these operators in large systems is becoming increasingly important, and also challenging current techniques. Significant performance improvements have been achieved by using state-of-the-art methods, such as reducing network traffic designed in the data management domain, and data flow scheduling in the data communications domain.
However, the proposed techniques in both fields just view each other as a black box, and performance gains from a co-optimization perspective have not yet been explored.
In this paper, based on current research in coflow scheduling,
we propose a novel Coflow-based Co-optimization Framework
(CCF), which can co-optimize application-level data movement
and network-level data communications for distributed operators,
and consequently contribute to their performance in
large distributed environments. We present the detailed design
and implementation of CCF, and conduct an experimental
evaluation of CCF using large-scale simulations on large data
joins. Our results demonstrate that CCF can always perform
faster than current approaches on network communications in
large-scale distributed scenarios.","big data; coflow scheduling; distributed joins; network communications; data-intensive applications","en","conference paper","IEEE","","","","","","","","","","Dataintensive Systems","","",""
"uuid:3d4487d0-85eb-49d3-90ad-5d6dceba7290","http://resolver.tudelft.nl/uuid:3d4487d0-85eb-49d3-90ad-5d6dceba7290","Slope failure with the material point method: An investigation of post-peak material behaviour","Vardon, P.J. (TU Delft Geo-engineering; Chinese Academy of Sciences); Wang, B. (Chinese Academy of Sciences); Hicks, M.A. (TU Delft Geo-engineering)","","2017","The material point method (MPM) has the potential to simulate the onset, the full evolution and the final condition of a slope failure. It is a variant of the finite element method (FEM), where the material is able to move through the mesh, thereby solving one of the major problems in FEM of mesh tangling. The post-peak material behaviour is shown here to be of importance to characterise the
failure, with an exploratory sensitivity analysis being presented highlighting the differences in the simulations. Realistic failure modes can be observed.","","en","conference paper","","","","","","","","","","","Geo-engineering","","",""
"uuid:fef219f6-1576-4202-b294-33f5271e8e5a","http://resolver.tudelft.nl/uuid:fef219f6-1576-4202-b294-33f5271e8e5a","Adversarial Cross-Modal Retrieval","Wang, Bokun (University of Electronic Science and Technology of China); Yang, Yang (University of Electronic Science and Technology of China); Xing, Xu (University of Electronic Science and Technology of China); Hanjalic, A. (TU Delft Multimedia Computing); Shen, Heng Tao (University of Electronic Science and Technology of China)","","2017","Cross-modal retrieval aims to enable flexible retrieval experience across different modalities (e.g., texts vs. images). The core of crossmodal retrieval research is to learn a common subspace where the items of different modalities can be directly compared to each other. In this paper, we present a novel Adversarial Cross-Modal Retrieval (ACMR) method, which seeks an effective common subspace based on adversarial learning. Adversarial learning is implemented as an interplay between two processes. The first process, a feature projector, tries to generate a modality-invariant representation in the common subspace and to confuse the other process, modality classifier, which tries to discriminate between different modalities based on the generated representation. We further impose triplet constraints on the feature projector in order to minimize the gap among the representations of all items from different modalities with same semantic labels, while maximizing the distances among semantically different images and texts. Through the joint exploitation of the above, the underlying cross-modal semantic structure of multimedia data is better preserved when this data is projected into the common subspace. Comprehensive experimental results on four widely used benchmark datasets show that the proposed ACMR method is superior in learning effective subspace representation and that it significantly outperforms the state-of-the-art cross-modal retrieval methods.","Adversarial learning; Cross-modal retrieval; Modality gap","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Multimedia Computing","","",""
"uuid:0b91ec0f-dc99-4c8d-98da-f3c3cd6f16d1","http://resolver.tudelft.nl/uuid:0b91ec0f-dc99-4c8d-98da-f3c3cd6f16d1","String Stability of Heterogeneous Platoons with Non-connected Automated Vehicles","Wang, M. (TU Delft Transport and Planning); Li, Honghai; GAO, Jian; Huang, Zichao; li, Bin; van Arem, B. (TU Delft Transport and Planning)","","2017","It is expected that automated vehicles will gradually penetrate on public roads, resulting in mixed traffic in the next decades. This can impact traffic flow operations, especially the roadway capacity and flow stability. It is of paramount
importance to understand and predict the implications of automated driving systems on traffic flow at the early design phase to avoid disruptive impacts on traffic. String stability properties of automated vehicle platoons are a fundamental
block to understand their traffic flow stability impact. Previous reports on string stability analysis focussed on homogeneous vehicle strings and simplify the time delays in vehicle systems. This work propose an analytical approach to determine string stability conditions for non-connected vehicle platoons with heterogeneous parameters. To this end, a third-order linear vehicle dynamics model is used in the control design and Laplace transform of the spacing and speed error dynamics in time domain to frequency domain enables the determination of sufficient string stability criteria of heterogeneous vehicle strings. The analytical string stability conditions give new insights into the relationship between the string stability properties of vehicle strings in relation to the system properties of time delays and controller design parameters of feedback gains and desired time gap. Analytical results are verified via
systematic simulation of both homogeneous and heterogeneous strings. Simulations demonstrate the predictive power of the analytical string stability conditions.","","en","conference paper","IEEE","","","","","","","","","Transport and Planning","Transport and Planning","","",""
"uuid:29b17dc4-ca5c-405d-8b38-83cc04224c3d","http://resolver.tudelft.nl/uuid:29b17dc4-ca5c-405d-8b38-83cc04224c3d","Draft Genome of Scalindua rubra, Obtained from the Interface Above the Discovery Deep Brine in the Red Sea, Sheds Light on Potential Salt Adaptation Strategies in Anammox Bacteria","Speth, Daan R. (Radboud Universiteit Nijmegen; California Institute of Technology); Lagkouvardos, Ilias (Technische Universität München); Wang, Yong (Chinese Academy of Sciences); Qian, Pei Yuan (The Hong Kong University of Science and Technology); Dutilh, Bas E. (Universiteit Utrecht; Universidade Federal do Rio de Janeiro; Radboud Universiteit Nijmegen); Jetten, M.S.M. (TU Delft BT/Environmental Biotechnology; Radboud Universiteit Nijmegen)","","2017","Several recent studies have indicated that members of the phylum Planctomycetes are abundantly present at the brine-seawater interface (BSI) above multiple brine pools in the Red Sea. Planctomycetes include bacteria capable of anaerobic ammonium oxidation (anammox). Here, we investigated the possibility of anammox at BSI sites using metagenomic shotgun sequencing of DNA obtained from the BSI above the Discovery Deep brine pool. Analysis of sequencing reads matching the 16S rRNA and hzsA genes confirmed presence of anammox bacteria of the genus Scalindua. Phylogenetic analysis of the 16S rRNA gene indicated that this Scalindua sp. belongs to a distinct group, separate from the anammox bacteria in the seawater column, that contains mostly sequences retrieved from high-salt environments. Using coverage- and composition-based binning, we extracted and assembled the draft genome of the dominant anammox bacterium. Comparative genomic analysis indicated that this Scalindua species uses compatible solutes for osmoadaptation, in contrast to other marine anammox bacteria that likely use a salt-in strategy. We propose the name Candidatus Scalindua rubra for this novel species, alluding to its discovery in the Red Sea.","Anammox; Genome binning; Metagenomics; Red Sea; Salt adaptation; Scalindua","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:be783bbb-1d0c-4276-8ba0-192b4e0feddb","http://resolver.tudelft.nl/uuid:be783bbb-1d0c-4276-8ba0-192b4e0feddb","Realistic car-following models for microscopic simulation of adaptive and cooperative adaptive cruise control vehicles","Xiao, L. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning)","","2017","Adaptive cruise control (ACC) and cooperative adaptive cruise control (CACC) are important technologies for the achievement of vehicle automation, and their effect on traffic systems generally is evaluated with microscopic traffic simulations. A successful simulation requires realistic vehicle behavior and minimal vehicle collisions. However, most existing ACC-CACC simulation studies used simplified models that were not based on real vehicle response. The studies rarely addressed collision avoidance in the simulation. The study presented in this paper developed a realistic and collision-free car-following model for ACC-CACC vehicles. A multiregime model combining a realistic ACC-CACC system with driver intervention for vehicle longitudinal motions is proposed. This model assumes that a human driver resumes vehicle control either according to his or her assessment or after a collision warning asks the driver to take over. The proposed model was tested in a wide range of scenarios to explore model performance and collision possibilities. The testing scenarios included three regular scenarios of stop-and-go, approaching, and cut-out maneuvers, as well as two extreme safetyconcerned maneuvers of hard brake and cut-in. The simulation results show that the proposed model is collision free in the full-speed-range operation with leader accelerations within -1 to 1 m/s2 and in approaching and cut-out scenarios. Those results indicate that the proposed ACC-CACC car-following model can produce realistic vehicle response without causing vehicle collisions in regular scenarios for vehicle string operations.","","en","journal article","","","","","","","","2019-01-05","","","Transport and Planning","","",""
"uuid:5c00582e-6a20-4e70-8f8e-992d3fbd8076","http://resolver.tudelft.nl/uuid:5c00582e-6a20-4e70-8f8e-992d3fbd8076","Net sediment transport in tidal basins: quantifying the tidal barotropic mechanisms in a unified framework","Gatto, V.M. (TU Delft Coastal Engineering); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Wang, Zhengbing (TU Delft Coastal Engineering)","","2017","Net sediment transport in tidal basins is a subtle imbalance between large fluxes produced by the flood/ebb alternation. The imbalance arises from several mechanisms of suspended transport. Lag effects and tidal asymmetries are regarded as dominant, but defined in different frames of reference (Lagrangian and Eulerian, respectively). A quantitative ranking of their effectiveness is therefore missing. Furthermore, although wind waves are recognized as crucial for tidal flats’ morphodynamics, a systematic analysis of the interaction with tidal mechanisms has not been carried out so far. We review the tide-induced barotropic mechanisms and discuss the shortcomings of their current classification for numerical
process-based models. Hence, we conceive a unified Eulerian framework accounting for wave-induced resuspension. A new methodology is proposed to decompose the sediment fluxes accordingly, which is applicable without needing (semi-) analytical approximations. The approach is tested with a one-dimensional model of the Vlie basin, Wadden Sea (The Netherlands). Results show that lag-driven transport is dominant for the finer fractions (silt and mud). In absence of waves, net sediment fluxes are landward and spatial (advective) lag effects are dominant. In presence of waves, sediment can be exported from the tidal flats and temporal (local) lag effects are dominant. Conversely, sand transport is dominated by the asymmetry of peak ebb/flood velocities. We show that the direction of lag-driven transport can be estimated by the gradient of hydrodynamic energy. In agreement with previous studies, our results support the conceptualization of tidal flats’ equilibrium as a simplified balance between tidal mechanisms and wave resuspension.","Wadden Sea; Settling lag; Tidal asymmetry; Residual transport; Tidal basins; Morphodynamics","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:69914913-ac51-46ae-a37e-a41020cd55da","http://resolver.tudelft.nl/uuid:69914913-ac51-46ae-a37e-a41020cd55da","Equilibria and Evolution of Estuarine Fringing Intertidal Mudflats","van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Grasso, F (Ifremer); le Hir, P (Ifremer); de Vet, P.L.M. (TU Delft Environmental Fluid Mechanics; Deltares); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares); Walles, B (NIOZ Royal Netherlands Institute for Sea Research); Ysebaert, Tom (NIOZ Royal Netherlands Institute for Sea Research; Wageningen University & Research)","","2017","Fringing intertidal flats are common features of elongated estuaries. We generalized the geometry of profiles of individual intertidal flats towards a common relationship, based on extensive measurement data of various estuaries. We found a strong linear relation between the width, slope and height of linear intertidal flat profiles, which also yields well for the mild-sloped upper part of convex-up profiles. Deviations of this linear relation at the lower steeper part of the flats are the result of dominating alongshore currents.","","en","abstract","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:e367721f-aba6-4ac1-9a96-af91298ffcfc","http://resolver.tudelft.nl/uuid:e367721f-aba6-4ac1-9a96-af91298ffcfc","Experimental analysis of railway track settlement in transition zones","Wang, Haoyu (TU Delft Railway Engineering); Markine, V.L. (TU Delft Railway Engineering); Liu, X. (TU Delft Railway Engineering)","","2017","Transition zones in railway tracks are the locations with considerable changes in the vertical support structures. Due to the differential stiffness and settlement in the open track and the engineering structure resulting in the dynamic amplification of the wheel forces, track settlement is usually observed in the approaching zones. The settlement in transition zones is detrimental to the track components and passenger comfort. This paper presents the results of the experimental analysis performed in three transition zones which were in various conditions. The dynamic displacements of rails due to passing trains were measured at multiple points (dynamic profile) in the approaching zones. The device employed is a contactless mobile device for measuring displacements, which is based on the digital image correlation technique. Because the operational parameters of the digital image correlation-based devices are important for measurement accuracy, prior to the in situ measurements, this device was tested in a laboratory to study the influence of the operational parameters, including the elevation/heading angles, the focal length of the cameras, and the measuring distance. After determining the optimal operational parameters for the railway field, multiple-point measurements were performed in the transition zones. The length of the approaching zone was studied first. Also, the dynamic profiles of the embankment–bridge and bridge–embankment transitions were analysed. Finally, by comparing the multiple-point displacements in the approaching zones in different conditions, it was found that the dynamic profile of the rail displacements has a good correlation with the track condition in the transition zone. The results are presented and discussed.","Railway; transition zone; measurement; digital image correlation","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:f12daca8-35ae-408f-b54a-dbb852d59637","http://resolver.tudelft.nl/uuid:f12daca8-35ae-408f-b54a-dbb852d59637","Integration of Traffic Information into the Path Planning among Moving Obstacles","Wang, Z. (TU Delft Urban Data Science); Steenbruggen, John (Vrije Universiteit Amsterdam); Zlatanova, S. (TU Delft Urban Data Science)","","2017","This paper investigates the integration of traffic information (TI) into the routing in the presence of moving obstacles. When traffic accidents occur, the incidents could generate different kinds of hazards (e.g., toxic plumes), which make certain parts of the road network inaccessible. On the other hand, the first responders, who are responsible for management of the traffic incidents, need to be fast and safely guided to the incident place. To support navigation in the traffic network affected by moving obstacles, in this paper, we provide a spatio-temporal data model to structure the information of traffic conditions that is essential for the routing, and present an extended path planning algorithm, named MOAAstar–TI (Moving Obstacle Avoiding A* using Traffic Information), to generate routes avoiding the obstacles. A speed adjustment factor is introduced in the developed routing algorithm, allowing integration of both the information of vehicles and traffic situations to generate routes avoiding the moving obstacles caused by the incidents. We applied our system to a set of navigation scenarios. The application results show the potentials of our system in future application in real life.","traffic incident management; spatial data model; routing algorithm; roving obstacles; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Urban Data Science","","",""
"uuid:7f10c742-83d5-4acf-96cc-8b023ce7ffe0","http://resolver.tudelft.nl/uuid:7f10c742-83d5-4acf-96cc-8b023ce7ffe0","Bed-level changes on intertidal wetland in response to waves and tides: A case study from the Yangtze River Delta","Zhu, Q. (TU Delft Coastal Engineering; East China Normal University); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Wang, Zhengbing (TU Delft Coastal Engineering; Deltares; East China Normal University); Yang, SL","","2017","Short-term bed-level variability in tidal wetlands has important implication both for ecology and engineering. In this study, we combined in situ measurements with model simulations to quantify short-term bed-level changes on a meso-macrotidal wetland in the Yangtze River Delta. On the middle flat, we observed erosion during neap-to-mean tides under onshore moderate-to-strong winds, and bed recovery during subsequent spring tides, when winds were both offshore and weaker, suggesting that winds can overturn the neap–spring cyclicity of bed-level changes even on meso–macrotidal mudflats. The magnitude of bed-level changes was smaller on both sides of the middle flat, while the smallest changes occurred on the salt marsh. Observed bed-level changes were reconstructed using a single-point bed-level change model, which incorporates in situ measured parameters of hydrodynamics (waves and currents), suspended sediment concentrations, and bed sediment properties. We conclude that the relative importance of waves and tides in intertidal wetland erosion and accretion can vary temporally (due to changes in balance between wave and tidal energies) and spatially (because of changes in elevation and vegetation in the cross-shore profile). Our study also reflects the advantage of combination of in situ measurement with simulation in detecting short-term variability of tidal flats.","","en","journal article","","","","","","","Campus only","","","","Coastal Engineering","","",""
"uuid:aec877b8-25e8-4db9-af4b-c24ad25a4f66","http://resolver.tudelft.nl/uuid:aec877b8-25e8-4db9-af4b-c24ad25a4f66","An Accurate BJT-Based CMOS Temperature Sensor With Duty-Cycle-Modulated Output","Wang, Guijie (Smartec BV); Heidari, A. (TU Delft Electronic Instrumentation); Makinwa, K.A.A. (TU Delft Microelectronics); Meijer, G.C.M. (TU Delft Electronic Instrumentation)","","2017","This paper describes the design of a precision bipolar junction transistor based temperature sensor implemented in standard 0.7-μmCMOS technology. It employs substrate p-n-ps as sensing elements,which makes it insensitive
to the effects of mechanical (packaging) stress and facilitates the use of low-cost packaging technologies. The sensor outputs a duty-cycle-modulated signal, which can easily be interfaced to the digital world and, after low-pass filtering, to the analog world. In order to eliminate the errors caused by the component mismatch, chopping and dynamic element matching (DEM) techniques have been applied. The required component shuffling was done concurrently rather than sequentially, resulting in a fast DEM scheme that saves energy without degrading accuracy. After a singletemperature trim, the sensor’s inaccuracy is ±0.1 °C (−20 to 60 °C) and ±0.3 °C (−45 to 130 °C), respectively. Measurements of sensors in different packages show that the package-induced shift is less than 0.1 °C. Measurements of eight sensors over 367 days show that their output drift is less than 6 mK. While dissipating only 200 μW, the sensor achieves a resolution of 3 mK (rms) in a 1.8-ms measurement time, and a state-of-the-art resolution figure of merit of 3.2 pJK2. This combination of high accuracy, high resolution, high speed, and low-energy consumption makes this sensor suited for commercial and industrial applications.","one-point trim; Chopping; CMOS temperature sensor; duty-cycle modulation; dynamic element matching (DEM)","en","journal article","","","","","","Accepted author manuscript","","","","Microelectronics","Electronic Instrumentation","","",""
"uuid:c39c50e1-a823-454f-a1f5-ecb10426afb7","http://resolver.tudelft.nl/uuid:c39c50e1-a823-454f-a1f5-ecb10426afb7","Change analysis in structural laser scanning point clouds: The baseline method","Shen, Y. (TU Delft Optical and Laser Remote Sensing; Hohai University); Lindenbergh, R.C. (TU Delft Optical and Laser Remote Sensing); Wang, J. (TU Delft Optical and Laser Remote Sensing; Chinese Academy of Sciences)","","2017","A method is introduced for detecting changes from point clouds that avoids registration. For many applications, changes are detected between two scans of the same scene obtained at different times. Traditionally, these scans are aligned to a common coordinate system having the disadvantage that this registration step introduces additional errors. In addition, registration requires stable targets or features. To avoid these issues, we propose a change detection method based on so-called baselines. Baselines connect feature points within one scan. To analyze changes, baselines connecting corresponding points in two scans are compared. As feature points either targets or virtual points corresponding to some reconstructable feature in the scene are used. The new method is implemented on two scans sampling a masonry laboratory building before and after seismic testing, that resulted in damages in the order of several centimeters. The centres of the bricks of the laboratory building are automatically extracted to serve as virtual points. Baselines connecting virtual points and/or target points are extracted and compared with respect to a suitable structural coordinate system. Changes detected from the baseline analysis are compared to a traditional cloud to cloud change analysis demonstrating the potential of the new method for structural analysis.","Baselines; Change detection; Masonry buildings; Structural analysis; Terrestrial laser scanning; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:a472564f-492d-4094-8de3-fdf53a84d095","http://resolver.tudelft.nl/uuid:a472564f-492d-4094-8de3-fdf53a84d095","Chemoenzymatic epoxidation of alkenes with Candida antarctica lipase B and hydrogen peroxide in deep eutectic solvents","Zhou, Pengfei (South China University of Technology); Wang, Xuping (South China University of Technology); Yang, Bo (South China University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Yonghua (South China University of Technology)","","2017","Epoxides are important synthetic intermediates for the synthesis of a broad range of industrial products. This study presents a promising solution to the current limitation of enzyme instability. By using simple deep eutectic solvents such as choline chloride/sorbitol, significant stabilization of the biocatalyst has been achieved leading to more robust reactions while using environmentally more acceptable solvents as compared to ionic liquids.","","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:34f368c1-ccbe-49f1-8752-33d1813212f4","http://resolver.tudelft.nl/uuid:34f368c1-ccbe-49f1-8752-33d1813212f4","Resilience of epidemics for SIS model on networks","Lu, Dan (Beihang University); Yang, Shunkun (Beihang University); Zhang, Jiaquan (Beihang University); Wang, H. (TU Delft Multimedia Computing); Li, Daqing (Beihang University)","","2017","Epidemic propagation on complex networks has been widely investigated, mostly with invariant parameters. However, the process of epidemic propagation is not always constant. Epidemics can be affected by various perturbations and may bounce back to its original state, which is considered resilient. Here, we study the resilience of epidemics on networks, by introducing a different infection rate λ2 during SIS (susceptible-infected-susceptible) epidemic propagation to model perturbations (control state), whereas the infection rate is λ1 in the rest of time. Noticing that when λ1 is below λc, there is no resilience in the SIS model. Through simulations and theoretical analysis, we find that even for λ2 < λc, epidemics eventually could bounce back if the control duration is below a threshold. This critical control time for epidemic resilience, i.e., cdmax, seems to be predicted by the diameter (d) of the underlying network, with the quantitative relation cdmax ~ dα. Our findings can help to design a better mitigation strategy for epidemics.","","en","journal article","","","","","","","","","","","Multimedia Computing","","",""
"uuid:5fa33d4a-8c02-4293-bc3a-eec0ac435488","http://resolver.tudelft.nl/uuid:5fa33d4a-8c02-4293-bc3a-eec0ac435488","Absorption heat pump cycles with NH3 – ionic liquid working pairs","Wang, M. (TU Delft Engineering Thermodynamics); Infante Ferreira, C.A. (TU Delft Engineering Thermodynamics)","","2017","Ionic liquids (ILs), as novel absorbents, draw considerable attention for their potential roles in replacing water or LiBr aqueous solutions in conventional NH3/H2O or H2O/LiBr absorption refrigeration or heat pump cycles. In this paper, performances of 9 currently investigated NH3/ILs pairs are calculated and compared in terms of their applications in the single-effect absorption heat pumps (AHPs) for the floor heating of buildings. Among them, 4 pairs were reported for the first time in absorption cycles (including one which cannot operate for this specific heat pump application). The highest coefficient of performance (COP) was found for the working pair using [mmim][DMP] (1.79), and pairs with [emim][Tf2N] (1.74), [emim][SCN] (1.73) and [bmim][BF4] (1.70) also had better performances than that of the NH3/H2O pair (1.61). Furthermore, an optimization was conducted to investigate the performance of an ideal NH3/IL pair. The COP of the optimized mixture could reach 1.84. Discussions on the contributions of the generator heat and optimization results revealed some factors that could affect the performance. It could be concluded that the ideal IL candidates should show high absorption capabilities, large solubility difference between inlet and outlet of the generator, low molecular weights and low heat capacities. In addition, an economic analysis of the AHP using NH3/[emim][SCN] working pair with plate heat exchangers was carried out based on heat transfer calculations. The results indicated that the NH3/IL AHP is economically feasible. The efforts of heat transfer optimization in the solution heat exchanger and a low expense of ILs can help the IL-based AHP systems to become more promising.","Absorption cycle; Economic analysis; Heat pump; ILs; NH; Optimization","en","journal article","","","","","","","","","","","Engineering Thermodynamics","","",""
"uuid:90e234ce-4ad1-4f03-bc53-b614d421b5f3","http://resolver.tudelft.nl/uuid:90e234ce-4ad1-4f03-bc53-b614d421b5f3","Mechanical characterization and cleaning of CVD single-layer h-BN resonators","Cartamil Bueno, S.J. (TU Delft QN/Steeneken Lab; Kavli institute of nanoscience Delft); Cavalieri, M. (Kavli institute of nanoscience Delft); Wang, Ruizhi (University of Cambridge); Houri, S. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft); Hofmann, Stephan (University of Cambridge); van der Zant, H.S.J. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft)","","2017","Hexagonal boron nitride is a 2D material whose single-layer allotrope has not been intensively studied despite being the substrate for graphene electronics. Its transparency and stronger interlayer adhesion with respect to graphene makes it difficult to work with, and few applications have been proposed. We have developed a transfer technique for this extra-adhesive material that does not require its visual localization, and fabricated mechanical resonators made out of chemical vapor-deposited single-layer hexagonal boron nitride. The suspended material was initially contaminated with polymer residues from the transfer, and the devices showed an unexpected tensioning when cooling them to 3 K. After cleaning in harsh environments with air at 450 °C and ozone, the temperature dependence changed with f0Q products reaching 2 × 1010 Hz at room temperature. This work paves the way to the realization of highly sensitive mechanical systems based on hexagonal boron nitride, which could be used as an alternative material to SiN for optomechanics experiments at room temperature.","","en","journal article","","","","","","","","","","","QN/Steeneken Lab","","",""
"uuid:34658b9c-2a0f-410a-a9a7-6c373852164a","http://resolver.tudelft.nl/uuid:34658b9c-2a0f-410a-a9a7-6c373852164a","On the origin of critical temperature enhancement in atomically thin superconductors","Talantsev, E. F. (Victoria University of Wellington); Crump, W. P. (Victoria University of Wellington); Island, J.O. (TU Delft QN/van der Zant Lab; Kavli institute of nanoscience Delft; University of California); Xing, Ying (Peking University; Collaborative Innovation Center of Quantum Matter; China University of Petroleum - Beijing); Sun, Yi (Peking University; Collaborative Innovation Center of Quantum Matter); Wang, Jian (Peking University; Collaborative Innovation Center of Quantum Matter); Tallon, J. L. (Victoria University of Wellington; MacDiarmid Institute for Advanced Materials and Nanotechnology)","","2017","Recent experiments showed that thinning gallium, iron selenide and 2H tantalum disulfide to single/several monoatomic layer(s) enhances their superconducting critical temperatures. Here, we characterize these superconductors by extracting the absolute values of the London penetration depth, the superconducting energy gap, and the relative jump in specific heat at the transition temperature from their self-field critical currents. Our central finding is that the enhancement in transition temperature for these materials arises from the opening of an additional superconducting gap, while retaining a largely unchanged 'bulk' superconducting gap. Literature data reveals that ultrathin niobium films similarly develop a second superconducting gap. Based on the available data, it seems that, for type-II superconductors, a new superconducting band appears when the film thickness becomes smaller than the out-of-plane coherence length. The same mechanism may also be the cause of enhanced interface superconductivity.","Atomically-thin superconductors; Coherence length; Critical currents; FeSe; London penetration depth; Superconducting energy gap; Transition metal dichalcogenides","en","journal article","","","","","","","","","","","QN/van der Zant Lab","","",""
"uuid:760a68ec-7737-42c2-af54-596c1d5bf5bd","http://resolver.tudelft.nl/uuid:760a68ec-7737-42c2-af54-596c1d5bf5bd","In vitro degradation and surface bioactivity of iron-matrix composites containing silicate-based bioceramic","Wang, S. (Chinese Academy of Sciences; Shanghai Institute of Technology); Xu, Y. (Shanghai Jiao Tong University); Zhou, J. (TU Delft Biomaterials & Tissue Biomechanics); Li, H. (Shanghai Jiao Tong University); Chang, Jiang (Chinese Academy of Sciences); Huan, Z. (Chinese Academy of Sciences)","","2017","Iron-matrix composites with calcium silicate (CS) bioceramic as the reinforcing phase were fabricated through powder metallurgy processes. The microstructures, mechanical properties, apatite deposition and biodegradation behavior of the Fe-CS composites, as well as cell attachment and proliferation on
their surfaces, were characterized. In the range of CS weight percentages selected in this study, the composites possessed compact structures and showed differently decreased bending strengths as compared with pure iron. Immersion tests in simulated body fluid (SBF) revealed substantially enhanced deposition of CaP on the surfaces of the composites as well as enhanced degradation rates as compared with pure iron. In addition, the composite containing 20% CS showed a superior ability to stimulate hBMSCs proliferation when compared to pure iron. Our results suggest that incorporating calcium silicate particles into iron could be an effective approach to developing iron-based biodegradable bone implants with improved biomedical performance.","","en","journal article","","","","","","","","","","","Biomaterials & Tissue Biomechanics","","",""
"uuid:2371e789-90d8-42aa-909d-546406fae24a","http://resolver.tudelft.nl/uuid:2371e789-90d8-42aa-909d-546406fae24a","Epidemic mitigation via awareness propagation in communication networks: The role of time scales","Wang, H. (TU Delft Multimedia Computing); Chen, Chuyi (External organisation); Qu, B. (TU Delft Multimedia Computing); Li, Daqing (Beihang University)","","2017","The participation of individuals in multi-layer networks allows for feedback between network layers, opening new possibilities to mitigate epidemic spreading. For instance, the spread of a biological disease such as Ebola in a physical contact network may trigger the propagation of the information related to this disease in a communication network, e.g. an online social network. The information propagated in the communication network may increase the awareness of some individuals, resulting in them avoiding contact with their infected neighbors in the physical contact network, which might protect the population from the infection. In this work, we aim to understand how the time scale γ of the information propagation (speed that information is spread and forgotten) in the communication network relative to that of the epidemic spread (speed that an epidemic is spread and cured) in the physical contact network influences such mitigation using awareness information. We begin by proposing a model of the interaction between information propagation and epidemic spread, taking into account the relative time scale γ. We analytically derive the average fraction of infected nodes in the meta-stable state for this model (i) by developing an individual-based mean-field approximation (IBMFA) method and (ii) by extending the microscopic Markov chain approach (MMCA). We show that when the time scale γ of the information spread relative to the epidemic spread is large, our IBMFA approximation is better compared to MMCA near the epidemic threshold, whereas MMCA performs better when the prevalence of the epidemic is high. Furthermore, we find that an optimal mitigation exists that leads to a minimal fraction of infected nodes. The optimal mitigation is achieved at a non-trivial relative time scale γ, which depends on the rate at which an infected individual becomes aware. Contrary to our intuition, information spread too fast in the communication network could reduce the mitigation effect. Finally, our finding has been validated in the real-world two-layer network obtained from the location-based social network Brightkite.","epidemic mitigation; epidemic spreading; interacting processes; multi-layer networks; time scale","en","journal article","","","","","","","","","","","Multimedia Computing","","",""
"uuid:219f5cf0-cc0e-442e-b627-7979ad910920","http://resolver.tudelft.nl/uuid:219f5cf0-cc0e-442e-b627-7979ad910920","A highly selective and stable ZnO-ZrO2 solid solution catalyst for CO2 hydrogenation to methanol","Wang, Jijie (Dalian University of Technology); Li, G. (TU Delft ChemE/Catalysis Engineering; Dalian University of Technology); Li, Zelong (Dalian University of Technology); Tang, Chizhou (Dalian University of Technology); Feng, Zhaochi (Dalian University of Technology); An, Hongyu (Chinese Academy of Sciences); Liu, Hailong (Dalian University of Technology); Liu, Taifeng (Dalian University of Technology); Li, Can (Dalian University of Technology)","","2017","Although methanol synthesis via CO hydrogenation has been industrialized, CO2 hydrogenation to methanol still confronts great obstacles of low methanol selectivity and poor stability, particularly for supported metal catalysts under industrial conditions. We report a binary metal oxide, ZnO-ZrO2 solid solution catalyst, which can achieve methanol selectivity of up to 86 to 91% with CO2 single-pass conversion of more than 10% under reaction conditions of 5.0 MPa, 24,000 ml/(g hour), H2/CO2 = 3:1 to 4:1, 320° to 315°C. Experimental and theoretical results indicate that the synergetic effect between Zn and Zr sites results in the excellent performance. The ZnO-ZrO2 solid solution catalyst shows high stability for at least 500 hours on stream and is also resistant to sintering at higher temperatures. Moreover, no deactivation is observed in the presence of 50 ppm SO2 or H2S in the reaction stream.","","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:c15a255b-65b6-4328-8df7-9f579c48b14d","http://resolver.tudelft.nl/uuid:c15a255b-65b6-4328-8df7-9f579c48b14d","Exploiting visual-based intent classification for diverse social image retrieval","Wang, Bo (External organisation); Larson, M.A. (TU Delft Multimedia Computing; Radboud Universiteit Nijmegen)","Gravier, Guillaume (editor); Bischke, Benjamin (editor); Demarty, Claire-Hélène (editor); Zaharieva, Maia (editor); Riegler, Michael (editor); Dellandrea, Emmanuel (editor); Bogdanov, Dmitry (editor); Sutcliffe, Richard (editor); Jones, Gareth J.F. (editor); Larson, Martha (editor)","2017","In the 2017 MediaEval Retrieving Diverse Social Images task, we (TUD-MMC team) propose a novel method, namely an intent-based approach, for social image search result diversification. The underlying assumption is that the visual appearance of social images is impacted by the underlying photographic act, i.e., why the images were taken. Better understanding the rationale behind the photographic act could potentially benefit social image search result diversification. To investigate this idea, we employ a manual content analysis approach to create a taxonomy of intent classes. Our experiments show that a CNN-based neural network classifier is able to capture the visual difference between the classes in the intent taxonomy. We cluster images of the Flickr baseline based on predicted intent class and generate a re-ranked list by alternating images from different clusters. Our results reveal that, compared to conventional diversification strategies, intent-based search result diversification is able to bring a considerable improvement in terms of cluster recall with several extra benefits.","","en","conference paper","","","","","","","","","","","Multimedia Computing","","",""
"uuid:3fa1ec27-01cf-49a2-a293-f31d9002d67a","http://resolver.tudelft.nl/uuid:3fa1ec27-01cf-49a2-a293-f31d9002d67a","A method for finding metabolic pathways using atomic group tracking","Huang, Yiran (South China University of Technology; Guangxi University); Zhong, Cheng (Guangxi University); Lin, H.X. (TU Delft Mathematical Physics); Wang, Jianyi (Guangxi University)","","2017","A fundamental computational problem in metabolic engineering is to find pathways between compounds. Pathfinding methods using atom tracking have been widely used to find biochemically relevant pathways. However, these methods require the user to define the atoms to be tracked. This may lead to failing to predict the pathways that do not conserve the user-defined atoms. In this work, we propose a pathfinding method called AGPathFinder to find biochemically relevant metabolic pathways between two given compounds. In AGPathFinder, we find alternative pathways by tracking the movement of atomic groups through metabolic networks and use combined information of reaction thermodynamics and compound similarity to guide the search towards more feasible pathways and better performance. The experimental results show that atomic group tracking enables our method to find pathways without the need of defining the atoms to be tracked, avoid hub metabolites, and obtain biochemically meaningful pathways. Our results also demonstrate that atomic group tracking, when incorporated with combined information of reaction thermodynamics and compound similarity, improves the quality of the found pathways. In most cases, the average compound inclusion accuracy and reaction inclusion accuracy for the top resulting pathways of our method are around 0.90 and 0.70, respectively, which are better than those of the existing methods. Additionally, AGPathFinder provides the information of thermodynamic feasibility and compound similarity for the resulting pathways.","","en","journal article","","","","","","","","","","","Mathematical Physics","","",""
"uuid:0c3909f3-e057-43de-987b-a6cda8bd96a2","http://resolver.tudelft.nl/uuid:0c3909f3-e057-43de-987b-a6cda8bd96a2","Fast ℓ1-regularized space-Time adaptive processing using alternating direction method of multipliers","Qin, Lilong (National University of Defense Technology); Wu, Manqing (China Electronics Technology Group Corporation); Wang, X. (TU Delft Microwave Sensing, Signals & Systems); Dong, Zhen (National University of Defense Technology)","","2017","Motivated by the sparsity of filter coefficients in full-dimension space-Time adaptive processing (STAP) algorithms, this paper proposes a fast ℓ1-regularized STAP algorithm based on the alternating direction method of multipliers to accelerate the convergence and reduce the calculations. The proposed algorithm uses a splitting variable to obtain an equivalent optimization formulation, which is addressed with an augmented Lagrangian method. Using the alternating recursive algorithm, the method can rapidly result in a low minimum mean-square error without a large number of calculations. Through theoretical analysis and experimental verification, we demonstrate that the proposed algorithm provides a better output signal-To-clutter-noise ratio performance than other algorithms.","alternating direction method of multipliers; generalized side-lobe canceler; recursive least-squares; space-Time adaptive processing; sparse representation","en","journal article","","","","","","","","","","","Microwave Sensing, Signals & Systems","","",""
"uuid:b2fd8457-c1e8-4807-8a37-cecb72173273","http://resolver.tudelft.nl/uuid:b2fd8457-c1e8-4807-8a37-cecb72173273","Pt-AlGaN/GaN HEMT-sensor layout optimization for enhancement of hydrogen detection","Sokolovskij, R. (State Key Laboratory of Solid State Lighting); Iervolino, E. (Southern University of Science and Technology); Zhao, Changhui (Southern University of Science and Technology); Wang, F. (Southern University of Science and Technology); Yu, Hongyu (Southern University of Science and Technology); Santagata, F. (TU Delft Electronic Components, Technology and Materials); Sarro, Pasqualina M (TU Delft Electronic Components, Technology and Materials); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials)","","2017","This paper reports on the layout optimization of Pt-AlGaN/GaN HEMT-sensors for enhancing hydrogen sensor performance. Sensors with gate width and length ratios Wg/Lg from 0.25 to 10 were designed, fabricated and tested for the detection of hydrogen gas at 200 °C. Sensitivity, sensing current variation and transient response are directly related to the sensor gate electrode Wg/Lg ratio. The obtained results demonstrated a 217 % increase in sensitivity and 4630 % increase in sensing current variation at 500 ppm H2 for a Wg/Lg from 0.25 to 10. In addition, the detection limit was lowered to 5 ppm. Transient characteristics demonstrated faster sensor response to H2, but slower recovery rates with increasing ratio.","AlGaN; GaN; H2 sensor; HEMT; high temperature; sensor layout","en","conference paper","IEEE","","","","","Accepted author manuscript","","","","","Electronic Components, Technology and Materials","","",""
"uuid:11d69060-4deb-407e-8def-92b3f8440650","http://resolver.tudelft.nl/uuid:11d69060-4deb-407e-8def-92b3f8440650","Spectroscopic evidence for bulk-band inversion and three-dimensional massive Dirac fermions in ZrTe5","Chen, Zhi Guo (Chinese Academy of Sciences); Chen, R. Y. (Peking University); Zhong, R. D. (Brookhaven National Laboratory); Schneeloch, John (Brookhaven National Laboratory); Zhang, C. (Brookhaven National Laboratory); Huang, Y. (Brookhaven National Laboratory); Qu, F. (TU Delft QRD/Kouwenhoven Lab; TU Delft QuTech Advanced Research Centre; Chinese Academy of Sciences); Yu, R. (Wuhan University); Li, Q. (Brookhaven National Laboratory); Gu, G. D. (Brookhaven National Laboratory); Wang, N. L. (Peking University; Collaborative Innovation Center of Quantum Matter)","","2017","Three-dimensional topological insulators (3D TIs) represent states of quantum matters in which surface states are protected by timereversal symmetry and an inversion occurs between bulk conduction and valence bands. However, the bulk-band inversion, which is intimately tied to the topologically nontrivial nature of 3D Tis, has rarely been investigated by experiments. Besides, 3D massive Dirac fermions with nearly linear band dispersions were seldom observed in TIs. Recently, a van der Waals crystal, ZrTe5, was theoretically predicted to be a TI. Here, we report an infrared transmission study of a high-mobility [∼33,000 cm2/(V · s)] multilayer ZrTe5 flake at magnetic fields (B) up to 35 T. Our observation of a linear relationship between the zero-magnetic-field optical absorption and the photon energy, a bandgap of ∼10 meV and a √B dependence of the Landau level (LL) transition energies at low magnetic fields demonstrates 3D massive Dirac fermions with nearly linear band dispersions in this system. More importantly, the reemergence of the intra-LL transitions at magnetic fields higher than 17 T reveals the energy cross between the two zeroth LLs, which reflects the inversion between the bulk conduction and valence bands. Our results not only provide spectroscopic evidence for the TI state in ZrTe5 but also open up a new avenue for fundamental studies of Dirac fermions in van der Waals materials.","Band inversion; Dirac fermions; Landau levels; Topological insulators; Zeeman splitting","en","journal article","","","","","","","","2018-07-31","","","QRD/Kouwenhoven Lab","","",""
"uuid:6fc49203-b2da-46f3-b11b-362d1ee4330c","http://resolver.tudelft.nl/uuid:6fc49203-b2da-46f3-b11b-362d1ee4330c","Spherical polyelectrolyte nanogels as templates to prepare hollow silica nanocarriers: observation by small angle X-ray scattering and TEM","Han, Haoya (East China University of Science and Technology); Li, Li (East China University of Science and Technology); Tian, Yuchuan (East China University of Science and Technology); Wang, Yunwei (East China University of Science and Technology); Ye, Zhishuang (East China University of Science and Technology); Yang, Qingsong (East China University of Science and Technology); Wang, Y. (TU Delft ChemE/Advanced Soft Matter; East China University of Science and Technology); Von Klitzing, Regine (Technische Universität Darmstadt); Guo, Xuhong (East China University of Science and Technology; Shihezi University)","","2017","Hollow silica nanoparticles were prepared through generating a silica layer in spherical polyelectrolyte nanogels (SPN), which consisted of a solid core of polystyrene (PS) and a shell of crosslinked poly(acrylic acid) (PAA), followed by removing the PS core via solvent dissolution. Small angle X-ray scattering (SAXS) in combination with TEM were employed to observe SPN, silica-polymer composite, and hollow silica nanoparticles. It was confirmed that SAXS is a powerful method to monitor the generation of silica layer in SPN. The density and thickness of generated silica layer in SPN were found to be tunable by controlling the crosslinking density of the templates. The porous structure and pH sensitivity of silica layer allowed the obtained hollow silica to be ideal carriers for controlled drug delivery.","","en","journal article","","","","","","","","","","","ChemE/Advanced Soft Matter","","",""
"uuid:1796eb34-d924-48d8-93b8-3958a223cb99","http://resolver.tudelft.nl/uuid:1796eb34-d924-48d8-93b8-3958a223cb99","Deep eutectic solvents as performance additives in biphasic reactions","Lan, Dongming (South China University of Technology); Wang, Xuping (Guangdong Academy of Agricultural Sciences); Zhou, Pengfei (Guangdong Academy of Agricultural Sciences); Hollmann, F. (TU Delft BT/Biocatalysis); Wang, Yonghua (South China University of Technology)","","2017","Deep eutectic solvents act as surfactants in biphasic (hydrophobic/aqueous) reaction mixtures enabling higher interfacial surface areas at lower mechanical stress as compared to simple emulsions. Exploiting this effect the rate of a chemoenzymatic epoxidation reaction was increased more than six-fold.","","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:3cf628b4-a4ba-4b45-81bb-72b71850f2d1","http://resolver.tudelft.nl/uuid:3cf628b4-a4ba-4b45-81bb-72b71850f2d1","Electrochemical reduction of CO2 on compositionally variant Au-Pt bimetallic thin films","Ma, M. (TU Delft ChemE/Materials for Energy Conversion and Storage); Hansen, Heine A. (Technical University of Denmark); Valenti, M. (TU Delft ChemE/Materials for Energy Conversion and Storage); Wang, Zegao (Aarhus University); Cao, A. (TU Delft OLD ChemE/Organic Materials and Interfaces; Eindhoven University of Technology); Dong, Mingdong (Aarhus University); Smith, W.A. (TU Delft ChemE/Materials for Energy Conversion and Storage)","","2017","The electrocatalytic reduction of CO2 on Au-Pt bimetallic catalysts with different compositions was evaluated, offering a platform for uncovering the correlation between the catalytic activity and the surface composition of bimetallic electrocatalysts. The Au-Pt alloy films were synthesized by a magnetron sputtering co-deposition technique with tunable composition. It was found that the syngas ratio (CO:H2) on the Au-Pt films is able to be tuned by systematically controlling the binary composition. This tunable catalytic selectivity is attributed to the variation of binding strength of COOH and CO intermediates, influenced by the surface electronic structure (d-band center energy) which is linked to the surface composition of the bimetallic films. Notably, a gradual shift of the d-band center away from the Fermi level was observed with increasing Au content, which correspondingly reduces the binding strength of the COOH and CO intermediates, leading to the distinct catalytic activity for the reduction of CO2 on the compositionally variant Au-Pt bimetallic films. In addition, the formation of formic acid in the bimetallic systems at reduced overpotentials and higher yield indicates that synergistic effects can facilitate reaction pathways for products that are not accessible with the individual components.","Au-Pt alloy thin films; Bimetallic catalysts; CO conversion; Electrocatalysis","en","journal article","","","","","","Accepted Author Manuscript","","","","","ChemE/Materials for Energy Conversion and Storage","","",""
"uuid:aaa057b4-73cd-4c22-a26c-62f0f709bbec","http://resolver.tudelft.nl/uuid:aaa057b4-73cd-4c22-a26c-62f0f709bbec","Tangible air: An Interactive Installation for Visualising Audience Engagement","Röggla, Thomas (Centrum Wiskunde & Informatica (CWI)); Wang, Chen (Centrum Wiskunde & Informatica (CWI)); Perez Romero, Lilia (Centrum Wiskunde & Informatica (CWI)); Jansen, Jack (Centrum Wiskunde & Informatica (CWI)); Cesar, Pablo (TU Delft Multimedia Computing; Centrum Wiskunde & Informatica (CWI))","","2017","This article presents an end-to-end system for capturing physiological sensor data and visualising it on a real-time graphic dashboard and as part of an art installation. More specifically, it describes an event where the level of engagement of the audience was measured by means of Galvanic Skin Response (GSR) sensors and of the presenter through a sweater fitted with GSR, ECG and acceleration sensors. The gathered data was presented in real-time through a visualisation projected onto a screen and a physical electro-mechanical installation, which would change the height of helium-filled balloons depending on the atmosphere in the auditorium. Thereby trying to create a tangible way of making the invisible visible.","Cultural experiences; Data visualization; GSR; Interactive art; Physical installation; Sensors; Shared experiences","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Multimedia Computing","","",""
"uuid:db01b396-9678-423c-ac3a-8d3108bbaf15","http://resolver.tudelft.nl/uuid:db01b396-9678-423c-ac3a-8d3108bbaf15","A conceptual framework of the human dimensions of urban emission in East Asia cities","Lee, Ying-Chieh (Lee-Ming Institute of Technology); Ko, Chia-Ying (Academia Sinica); Lin, Y. (TU Delft Spatial Planning and Strategy); Wang, Chi-Yun (Taiwan University); Huang, Chun-Wei (Yale University); Seto, Karen C.","","2017","Eight East Asian countries are home to approximately one-quarter of the world’s urban population, and by 2050, the combined urban population of these countries is expected to increase to 1.29 billion from 881 million today. Thus a central challenge for East Asian cities is how to pursue more low-carbon urbanization pathways. One of the key messages of the new chapter on urban mitigation of climate change in the IPCC Fifth Assessment Report is that certain urban form characteristics, especially co-located high population and employment densities coupled with mixed land use, can result in lower per capita urban emissions. However, East Asian cities already have some of the highest urban population densities in the world, suggesting that altering urban form alone will be a limited mitigation strategy for these places. Here we present a conceptual framework of the underlying factors that shape urban form and affect the use of urban space in East Asian cities. The main thesis of the framework is that urban form is the outcome of historical legacies and modes of governance, and that the use of urban space is deeply influenced by social norms and cultural attitudes. Especially for cities where urban form is established or difficult to change, the framework helps to identify factors that interact with urban form to enable low-carbon urban behavior. The framework offers a solution space for climate change mitigation and sharing of lessons learned that are applicable for East Asia, one of the most rapidly urbanizing regions in the world.","low-carbon urban form; human dimension; governance; East Asia","en","conference paper","Elsevier","","","","","","","","","","Spatial Planning and Strategy","","",""
"uuid:324ea62f-d403-42d8-afc6-8508f026a119","http://resolver.tudelft.nl/uuid:324ea62f-d403-42d8-afc6-8508f026a119","EARLINET instrument intercomparison campaigns: Overview on strategy and results","Wandinger, U.; Freudenthaler, V.; Baars, H.; Amodeo, A.; Engelmann, R.; Mattis, I.; Gross, S.; Pappalardo, G.; Giunta, G.; D'Amico, G.; Chaikovsky, A.; Osipenko, F.; Slesar, A.; Nicolae, D.; Belegante, L.; Talianu, C.; Serikov, I.; Linne, H.; Jansen, F.; Apituley, A.; Wilson, K.M.; de Graaf, M.; Trickl, T.; Giehl, H.; Adam, D.; Comeron, A.; Munoz-Porcar, C.; Rocadenbosch, F.; Sicard, M.; Tomas, S.; de Lange, D.; Kumar, D.; Pujadas, M.; Molero, F.; Fernandez, A.F.; Alados-Arboledas, L.; Bravo-Aranda, J.A.; Navas-Guzman, F.; Guerrero-Rascado, J.L.; Granados-Munoz, M.J.; Preissler, J.; Wagner, F.; Gausa, M.; Grigorov, I.; Stoyanov, D.; Iarlori, M.; Rizi, V.; Spinelli, N.; Boselli, A.; Wang, X.; lo Feudo, F.; Perrone, M.R.; de Tomasi, F.; Burlizzi, P.","","2016","This paper introduces the recent European Aerosol Research Lidar Network (EARLINET) quality-assurance efforts at instrument level. Within two dedicated campaigns and five single-site intercomparison activities, 21 EARLINET systems from 18 EARLINET stations were intercompared between 2009 and 2013. A comprehensive strategy for campaign setup and data evaluation has been established. Eleven systems from nine EARLINET stations participated in the EARLINET Lidar Intercomparison 2009 (EARLI09). In this campaign, three reference systems were qualified which served as traveling standards thereafter. EARLINET systems from nine other stations have been compared against these reference systems since 2009.We present and discuss comparisons at signal and at product level from all campaigns for more than 100 individual measurement channels at the wavelengths of 355, 387, 532, and 607 nm. It is shown that in most cases, a very good agreement of the compared systems with the respective reference is obtained. Mean signal deviations in predefined height ranges are typically below +- 2 %. Particle backscatter and extinction coefficients agree within +-2x10-4 km-1 sr-1 and +-0.01 km-1, respectively, in most cases. For systems or channels that showed larger discrepancies, an in-depth analysis of deficiencies was performed and technical solutions and upgrades were proposed and realized. The intercomparisons have reinforced confidence in the EARLINET data quality and allowed us to draw conclusions on necessary system improvements for some instruments and to identify major challenges that need to be tackled in the future.","","en","journal article","European Geosciences Union","","","","","","","","Civil Engineering and Geosciences","Geoscience and Remote Sensing","","","",""
"uuid:c107cc92-d275-45df-ad56-b754e8ead98c","http://resolver.tudelft.nl/uuid:c107cc92-d275-45df-ad56-b754e8ead98c","Robustness of complex networks: Theory and application","Wang, X. (TU Delft Network Architectures and Services)","Van Mieghem, P.F.A. (promotor); Kooij, Robert (promotor); Delft University of Technology (degree granting institution)","2016","Failures of networks, such as power outages in power systems, congestions in
transportation networks, paralyse our daily life and introduce a tremendous cascading effect on our society. Networks should be constructed and operated in a robust way against random failures or deliberate attacks.
We study how to add a single link into an existing network such that the robustness of the network is maximally improved among all the possibilities. A graph metric, the effective graph resistance, is employed to quantify the robustness of the network. Though exhaustive search guarantees the optimal solution, the computational complexity is high and is not scalable with the increase of network size. We propose strategies that take into account the structural and spectral properties of networks and indicate links whose addition result in a high robustness level.","Complex Networks; Robustness of Networks; Graph Spectra; Power Grids; Metro Networks; Line Graph; Eigenvectors/Eigenvalues; Interdependent Networks","en","doctoral thesis","","978-94-6186-775-9","","","","","","","","","Network Architectures and Services","","",""
"uuid:624e0a6f-854f-463b-be4c-62af81f363ad","http://resolver.tudelft.nl/uuid:624e0a6f-854f-463b-be4c-62af81f363ad","Finite Element Analysis and Experimental Validation of Eddy Current Losses in Permanent Magnet Machines with Fractional-Slot Concentrated Windings","Wang, X. (TU Delft DC systems, Energy conversion & Storage); Liu, D. (TU Delft DC systems, Energy conversion & Storage); Lahaye, D.J.P. (TU Delft Numerical Analysis); Polinder, H. (TU Delft DC systems, Energy conversion & Storage); Ferreira, Jan Abraham (TU Delft Electrical Power Processing)","","2016","Permanent-magnet machines with fractional slot concentrated windings are easy to manufacture. Their popularity therefore is steadily increasing. Without a proper design, however, the induced eddy-current losses in the solid rotor get rather high. The modeling and the prediction of eddy-current losses for these machines are thus very important during the design process. This paper focuses on the finite-element analysis and the experimental validation of eddy-current losses for this kind of machine with a small axial length. Two-dimensional and three-dimensional transient finite-element models are developed for computing the eddy-current losses. The rotor motion is taken into account using an Arbitrary Lagrangian-Eulerian formulation. The total iron losses are measured experimentally and a method to separate the rotor iron losses from the total iron losses is presented. The validation results show that the twodimensional finite-element model overestimates the losses due to the end-effects being neglected. The three-dimensional model agrees much better with the measurements in both no-load and on-load operations.","Concentrated winding; eddy current losses; experimental validation; permanent magnet machine","en","conference paper","IEEE","","","","","","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:cf86eb85-ae80-4085-bb56-63a2f296bc84","http://resolver.tudelft.nl/uuid:cf86eb85-ae80-4085-bb56-63a2f296bc84","3D Cadastre Visualization: Recent Progress and Future Directions","Pouliot, Jacynthe; Hubert, Frédéric; Wang, Chen; Ellul, Claire; Rajabifard, Abbas","","2016","The 3D Cadastre has been investigated from many viewpoints (including legal, organizational and technical). However, to date little research has focused specifically on visualizationrelated aspects despite the value-added of the third dimension. The paper first proposes an overview of progress made in the last five years in 3D cadastral visualization. The authors then summarize discussions at the 2014 3D Cadastre workshop regarding future research and development on the topic. This synthesis is complemented by a broad review of the most recent advances in 3D visualization beyond the 3D cadastral domain, with the goal of providing a number of important directions for further work, allowing researchers, developers and users to consolidate their respective activities, and encouraging collaboration.","Interaction; 3D Cadastral Visualization; Users; User Requirements; Usability; modelling; Presenting Information; 3D Environments","en","conference paper","","","","","","","","","","","","","",""
"uuid:29b7ab5f-40ec-464b-a8f0-e24284a439f0","http://resolver.tudelft.nl/uuid:29b7ab5f-40ec-464b-a8f0-e24284a439f0","Electrical and mechanical properties of asphalt concrete containing conductive fibers and fillers","Wang, H. (TU Delft Engineering Structures); Yang, Jun (Southeast University); Liao, Hui (Southeast University); Chen, Xianhua (Southeast University)","","2016","Electrically conductive asphalt concrete has the potential to satisfy multifunctional applications. Designing such asphalt concrete needs to balance the electrical and mechanical performance of asphalt concrete. The objective of this study is to design electrically conductive asphalt concrete without compromising on the mechanical properties of asphalt concrete. In order to achieve this goal, various tests have been conducted to investigate the effects of electrically conductive additives (steel fiber and graphite) on the laboratory-measured electrical and mechanical properties of asphalt concrete. The results from this study indicate that the critical embedded steel fiber length is 9.6 mm to maximize the fiber's potential to bridge across the crack from single fiber tensile test. Both steel fiber and graphite can produce conductive asphalt concrete with sufficiently low resistivity, but steel fiber is much more effective than graphite to improve the conductivity of asphalt concrete. A combination of steel fiber and graphite can precisely control the resistivity of asphalt concrete over a wider range. Besides, asphalt concrete containing an optimized amount of steel fibers has a significant improvement in Marshall Stability, rutting resistance, indirect tensile strength, and low temperature cracking resistance compared to the plain concrete. The addition of graphite could increase the permanent deformation resistance with compromised stability and low temperature performance. Asphalt concrete containing steel fibers and graphite weakens the steel fiber reinforcing and toughening effect, but still has a significant improvement in mechanical performance compared to the plain concrete.","Asphalt concrete; Electrical conductivity; Fiber; Graphite; Mechanical properties","en","journal article","","","","","","","","2018-10-01","","Engineering Structures","","","",""
"uuid:09cbdc66-a12e-4089-93fd-cc8dc533a1d0","http://resolver.tudelft.nl/uuid:09cbdc66-a12e-4089-93fd-cc8dc533a1d0","Removal of Microcystis aeruginosa by UV-activated persulfate: Performance and characteristics","Wang, Zongping (Huazhong University of Science and Technology); Chen, Yiqun (Huazhong University of Science and Technology); Xie, Pengchao (Huazhong University of Science and Technology); Shang, R. (TU Delft Sanitary Engineering); Ma, Jun (Harbin Institute of Technology)","","2016","Cyanobacteria blooms in source waters have become a worldwide issue for drinking water production. UV-activated persulfate (UV/PS) technology was firstly applied to remove cultivated Microcystis aeruginosa (M. aeruginosa) in bench scale. The presence of persulfate significantly enhanced both cytoclasis and algal organic matter mineralization compared with UV-C inactivation alone. Around 98.2% of algal cells were removed after UV/PS process treatment for 2 h at a dosage of PS being 1500 mg/L (approximately 6 mM). Both sulfate and hydroxyl radicals were proven to contribute to the removal of algae and the loss of cell integrity. The cultivated M. aeruginosa in death growth phase were found to be more vulnerable to UV/PS treatment than those growing in log phase, thus a significant lower dosage of PS is needed to achieve the desired removal efficiency. This study suggested a novel application of UV/PS process in the removal of algae in source waters due to the high degradation efficiency of both algal cells and their derived organic matter.","Algal organic matter; Cell integrity; Microcystis aeruginosa; Persulfate; Ultraviolet","en","journal article","","","","","","","","2018-09-30","","","Sanitary Engineering","","",""
"uuid:8a7501c9-235c-4e32-b7a0-54102d407fcb","http://resolver.tudelft.nl/uuid:8a7501c9-235c-4e32-b7a0-54102d407fcb","Creation of an anti-imaging system using binary optics","Wang, Haifeng (University of Shanghai for Science and Technology); Lin, Jian (University of Shanghai for Science and Technology); Zhang, Dawei (University of Shanghai for Science and Technology); Wang, Yang (Chinese Academy of Sciences); Gu, Min (Royal Melbourne Institute of Technology University); Urbach, Paul (TU Delft ImPhys/Optics); Gan, Fuxi (Chinese Academy of Sciences); Zhuang, Songlin (University of Shanghai for Science and Technology)","","2016","We present a concealing method in which an anti-point spread function (APSF) is generated using binary optics, which produces a large-scale dark area in the focal region that can hide any object located within it. This result is achieved by generating two identical PSFs of opposite signs, one consisting of positive electromagnetic waves from the zero-phase region of the binary optical element and the other consisting of negative electromagnetic waves from the pi-phase region of the binary optical element.","Imaging and sensing; Optical manipulation and tweezers; Terahertz optics; Transformation optics","en","journal article","","","","","","","","","","","ImPhys/Optics","","",""
"uuid:b4cce9d1-1cdb-49bb-950b-6627e2a18680","http://resolver.tudelft.nl/uuid:b4cce9d1-1cdb-49bb-950b-6627e2a18680","Relating the 3D electrode morphology to Li-ion battery performance; a case for LiFePO4","Liu, Zhao (Northwestern University); Verhallen, T.W. (TU Delft RST/Fundamental Aspects of Materials and Energy); Singh, D.P. (TU Delft RST/Fundamental Aspects of Materials and Energy); Wang, Hongqian (Northwestern University); Wagemaker, M. (Northwestern University); Barnett, Scott (Northwestern University)","","2016","One of the main goals in lithium ion battery electrode design is to increase the power density. This requires insight in the relation between the complex heterogeneous microstructure existing of active material, conductive additive and electrolyte providing the required electronic and Li-ion transport. FIB-SEM is used to determine the three phase 3D morphology, and Li-ion concentration profiles obtained with Neutron Depth Profiling (NDP) are compared for two cases, conventional LiFePO4 electrodes and better performing carbonate templated LiFePO4 electrodes. This provides detailed understanding of the impact of key parameters such as the tortuosity for electron and Li-ion transport though the electrodes. The created hierarchical pore network of the templated electrodes, containing micron sized pores, appears to be effective only at high rate charge where electrolyte depletion is hindering fast discharge. Surprisingly the carbonate templating method results in a better electronic conductive CB network, enhancing the activity of LiFePO4 near the electrolyte-electrode interface as directly observed with NDP, which in a large part is responsible for the improved rate performance both during charge and discharge. The results demonstrate that standard electrodes have a far from optimal charge transport network and that significantly improved electrode performance should be possible by engineering the microstructure.","3D imaging; Charge transport; Electrode morphology; FIB-SEM; Li-ion batteries; LiFePO; Neutron depth profiling","en","journal article","","","","","","Accepted Author Manuscript","","2018-05-30","","","RST/Fundamental Aspects of Materials and Energy","","",""
"uuid:1fa3b9e8-a7ad-44f7-a9d6-96921ee29db1","http://resolver.tudelft.nl/uuid:1fa3b9e8-a7ad-44f7-a9d6-96921ee29db1","Fundamental Understanding of the Di-Air System: The Role of Ceria in NOx Abatement","Wang, Y. (TU Delft ChemE/Catalysis Engineering); Posthuma De Boer, J (TU Delft ChemE/Catalysis Engineering); Kapteijn, F. (TU Delft ChemE/Catalysis Engineering); Makkee, M. (TU Delft ChemE/Catalysis Engineering)","","2016","Temporal analysis of product (TAP) is used to investigate the effectiveness of CO, C3H6, and C3H8 in the reduction of a La–Zr doped ceria catalyst and NO reduction into N2 over this pre-reduced catalyst. Hydrocarbons are found to be substantially more effective in the reduction of this catalyst at high temperature (above 500 °C) as compared to CO. NO decomposes over oxygen anion defects created upon catalyst reduction. Deposited carbon, in case the catalyst is reduced by C3H6 or C3H8, acts as a delayed or stored reductant and is not directly involved in NO reduction. Instead the oxidation of deposited carbon by an oxygen species derived from lattice oxygen (re)creates the oxygen anion defects active in NO reduction. In situ Raman, in which NO is flown over C3H6 pre-reduced La–Zr doped ceria at 560 °C, additionally shows that re-oxidation of the La–Zr doped ceria catalyst starts prior to the oxidation of deposited carbon, which confirms our TAP findings that firstly NO re-oxidized the La–Zr doped ceria catalyst and that secondly the oxidation of deposited carbon only commences at a higher ceria oxidation state. These findings create a new perspective on the operating principle of Toyota’s Di-Air system.","Ceria; Di-air; Hydrocarbon oxidation; NO reduction; TAP","en","journal article","","","","","","","","","","","ChemE/Catalysis Engineering","","",""
"uuid:72891061-1a7c-4259-af45-72078352dc05","http://resolver.tudelft.nl/uuid:72891061-1a7c-4259-af45-72078352dc05","Moving Human path tracking based on video surveillance in 3D indoor scenarious","Zhou, Yan (University of Electric Science and Technology of China, Chengdu); Zlatanova, S. (TU Delft Urban Data Science); Wang, Zhe (University of Electric Science and Technology of China, Chengdu); Zhang, Yeting (Wuhan University); Liu, L. (TU Delft Urban Data Science)","","2016","Video surveillance systems are increasingly used for a variety of 3D indoor applications. We can analyse human behaviour, discover and avoid crowded areas, monitor human traffic and so forth. In this paper we concentrate on use of surveillance cameras to track and reconstruct the path a person has followed. For the purpose we integrated video surveillance data with a 3D indoor model of the building and develop a single human moving path tracking method. We process the surveillance videos to detected single human moving traces; then we match the depth information of 3D scenes to the constructed 3D indoor network model and define the human traces in the 3D indoor space. Finally, the single human traces extracted from multiple cameras are connected with the help of the connectivity provided by the 3D network model. Using this approach, we can reconstruct the entire walking path. The provided experiments with a single person have verified the effectiveness and robustness of the method","Moving Object Tracking; Video Surveillance; 3D Indoor Scenario","en","journal article","","","","","","","","","","","Urban Data Science","","",""
"uuid:0ea69164-249d-4698-ab48-db94e369d5c7","http://resolver.tudelft.nl/uuid:0ea69164-249d-4698-ab48-db94e369d5c7","Connected variable speed limits control and car-following control with vehicle-infrastructure communication to resolve stop-and-go waves","Wang, M. (TU Delft Transport and Planning); Daamen, W. (TU Delft Transport and Planning); Hoogendoorn, S.P. (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning)","","2016","The vision of intelligent vehicles traveling in road networks has prompted numerous concepts to control future traffic flow, one of which is the in-vehicle actuation of traffic control commands. The key of this concept is using intelligent vehicles as actuators for traffic control systems. Under this concept, we design and test a control system that connects a traffic controller with in-vehicle controllers via vehicle-to-infrastructure communication. The link-level traffic controller regulates traffic speeds through variable speed limits (VSL) gantries to resolve stop-and-go waves, while intelligent vehicles control accelerations through vehicle propulsion and brake systems to optimize their local situations. It is assumed that each intelligent vehicle receives VSL commands from the traffic controller and uses them as variable parameters for the local vehicle controller. Feasibility and effectiveness of the connected control paradigm are tested with simulation on a two-lane freeway stretch with intelligent vehicles randomly distributed among human-driven vehicles. Simulation shows that the connected VSL and vehicle control system improves traffic efficiency and sustainability; that is, total time spent in the network and average fuel consumption rate are reduced compared to (uncontrolled and controlled) scenarios with 100% human drivers and to uncontrolled scenarios with the same intelligent vehicle penetration rates.","adaptive cruise control; connected vehicles; moving jam; variable speed limits","en","journal article","","","","","","","Campus only","","","Transport and Planning","Transport and Planning","","",""
"uuid:6acc4e38-5e6e-4ab3-8f32-7aa868ca6f04","http://resolver.tudelft.nl/uuid:6acc4e38-5e6e-4ab3-8f32-7aa868ca6f04","Biological Nitrogen Removal in a Photosequencing Batch Reactor with an Algal-Nitrifying Bacterial Consortium and Anammox Granules","Manser, Nathan D. (University of South Florida Tampa); Wang, Meng (University of South Florida Tampa); Ergas, Sarina J. (University of South Florida Tampa); Mihelcic, James R. (University of South Florida Tampa); Mulder, Arnold (Amecon Environmental Consultancy); Van De Vossenberg, Jack (IHE Delft Institute for Water Education); van Lier, J.B. (TU Delft Sanitary Engineering; IHE Delft Institute for Water Education); Van Der Steen, Peter (IHE Delft Institute for Water Education)","","2016","This study demonstrates the feasibility of combining microalgae, ammonia-oxidizing bacteria (AOB), and Anammox in a photosequencing batch reactor. Alternating light and dark periods were applied to achieve biological nitrogen removal without mechanical aeration or external electron donor addition. This process is termed ALGAMMOX (algal anaerobic ammonium oxidation) and differs from the SHARON-Anammox process in that oxygen is generated during light periods through microalgal photosynthesis, replacing mechanical aeration. Results from bench-scale ALGAMMOX experiments with high-ammonia strength wastewater (COD/TN from 1 to 3) showed that influent ammonia was converted to nitrite during light periods at a rate of 7.0 mg of NH4 +-N L-1 h-1. Nitrite was subsequently reduced by an average of 82% during the dark (anoxic) periods due to Anammox activity. Further studies are needed to optimize the system to maximize nitrogen removal rates and to assess long-term process stability.","","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:9a6785ea-ed71-4d2b-b009-436699ed302a","http://resolver.tudelft.nl/uuid:9a6785ea-ed71-4d2b-b009-436699ed302a","Intercomparison of methods of coupling between convection and large-scale circulation: 2. Comparison over nonuniform surface conditions","Daleu, C. L. (University of Reading); Plant, R. S. (University of Reading); Woolnough, S. J. (University of Reading); Sessions, S. (New Mexico Tech); Herman, M. J. (New Mexico Tech); Sobel, AH (Columbia University); Wang, S. (Columbia University); Kim, D. (University of Washington); cheng, A (NASA Langley Research Center); Bellon, G. (The University of Auckland); Peyrille, P. (Meteo France); Ferry, F. (Meteo France); Siebesma, A.P. (TU Delft Atmospheric Physics; TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI)); Ulft, LH (Royal Netherlands Meteorological Institute (KNMI))","","2016","As part of an international intercomparison project, the weak temperature gradient (WTG) and damped gravity wave (DGW) methods are used to parameterize large-scale dynamics in a set of cloud-resolving models (CRMs) and single column models (SCMs). The WTG or DGW method is implemented using a configuration that couples a model to a reference state defined with profiles obtained from the same model in radiative-convective equilibrium. We investigated the sensitivity of each model to changes in SST, given a fixed reference state. We performed a systematic comparison of the WTG and DGW methods in different models, and a systematic comparison of the behavior of those models using the WTG method and the DGW method. The sensitivity to the SST depends on both the large-scale parameterization method and the choice of the cloud model. In general, SCMs display a wider range of behaviors than CRMs. All CRMs using either the WTG or DGW method show an increase of precipitation with SST, while SCMs show sensitivities which are not always monotonic. CRMs using either the WTG or DGW method show a similar relationship between mean precipitation rate and column-relative humidity, while SCMs exhibit a much wider range of behaviors. DGW simulations produce large-scale velocity profiles which are smoother and less top-heavy compared to those produced by the WTG simulations. These large-scale parameterization methods provide a useful tool to identify the impact of parameterization differences on model behavior in the presence of two-way feedback between convection and the large-scale circulation.","large-scale parameterized dynamics; tropical convection","en","journal article","","","","","","","","","","","Atmospheric Physics","","",""
"uuid:66deb7b5-ab26-4f08-8d4b-c5cdf01ad7bd","http://resolver.tudelft.nl/uuid:66deb7b5-ab26-4f08-8d4b-c5cdf01ad7bd","Velocity analysis of simultaneous-source data using high-resolution semblance: Coping with the strong noise","Gan, S.; Wang, S.; Chen, Y.; Qu, S.; Zu, S.","","2016","Direct imaging of simultaneous-source (or blended) data, without the need of deblending, requires a precise subsurface velocity model. In this paper, we focus on the velocity analysis of simultaneous-source data using the normal moveout-based velocity picking approach.We demonstrate that it is possible to obtain a precise velocity model directly from the blended data in the common-midpoint domain. The similarity-weighted semblance can help us obtain much better velocity spectrum with higher resolution and higher reliability compared with the traditional semblance. The similarity-weighted semblance enforces an inherent noise attenuation solely in the semblance calculation stage, thus it is not sensitive to the intense interference. We use both simulated synthetic and field data examples to demonstrate the performance of the similarity-weighted semblance in obtaining reliable subsurface velocity model for direct migration of simultaneous-source data. The migrated image of blended field data using prestack Kirchhoff time migration approach based on the picked velocity from the similarity-weighted semblance is very close to the migrated image of unblended data.","image processing; controlled source seismology","en","journal article","Oxford University Press","","","","","","","","Applied Sciences","ImPhys/Imaging Physics","","","",""
"uuid:a05a8c81-5f02-4d12-9417-8fdba05e6983","http://resolver.tudelft.nl/uuid:a05a8c81-5f02-4d12-9417-8fdba05e6983","Isogeometric Shape Optimization for Quasi-static and Transient Problems","Wang, Z.P.","Bisagni, C. (promotor); Turteltaub, S.R. (promotor)","2016","The recently developed isogeometric analysis (IGA) was aimed, from the start, at integrating computer aided design (CAD) and analysis. This synthesis of geometry and analysis has naturally led to renewed interest in developing structural shape optimization. The advantages of using isogeometric analysis in shape optimization are embodied in its ability to preserve exact CAD geometrical descriptions and its enhanced potential to perform shape sensitivity analysis. Recent contributions in shape optimization within IGA have been limited to static or steady-state loading conditions. The purpose of this work was to extend the isogeometric shape optimization and identification to quasi-static and transient problems. The normalization approaches for the search directions in isogeometric shape optimization scheme and the mean value property of B-spline basis were also studied. Shape sensitivity analysis plays a critical role in structural shape optimization. In this dissertation, an adjoint sensitivity analysis was performed for arbitrary objective functionals defined for quasi-static and transient problems at the continuous level. The sensitivity for quasi-static and transient problems are essentially different with each other since the transient case has a time-derivative term involved in the time interval. The transport relations considering discontinuities were studied and used to derive the continuous adjoint shape sensitivity. Consideration of the discontinuities enabled the shape sensitivity analysis to be applicable for the problems where discontinuities were involved in the objective functional and state equations. Then within the context of IGA, the continuous sensitivity was discretized to obtain the discrete design sensitivity with respect to the design discretization, which was used to find the search directions used to update the shape numerically. A interesting phenomenon in shape optimization is that the use of the search direction directly predicted from the discrete shape gradient makes the optimization history strongly dependent on the discretization. This discretization dependency can affect convergence and may lead the optimization process into a sub-optimal solution. The source of this discretization dependency was traced to the lack of consistency with the local steepest descent search direction in the continuous formulation. This inconsistency was analyzed using the shape variation equations and subsequently illustrated with a volume minimization problem. It was found that the inconsistency originates from the NURBS discretization which induces a discrete quadratic norm to represent the continuous Euclidean norm. To fix this inconsistency, a standard normalization approach, which is used to find the steepest descent direction for quadratic norm problems, was proposed to obtain a consistent discretization independent search direction. The standard approach requires solving a linear system of equations. Using the diagonally lumped mapping matrix (DLMM) and the partition of unity property of NURBS, two simpler normalization approaches, which do not require solving a linear system of equations, were proposed. The discretization-independence of the proposed approaches was verified with a benchmark problem. The superiority of the proposed search direction and its suitability for numerical implementation is illustrated with examples of shape optimization for mechanical and thermal problems. In the derivation of the simplified normalization approaches, the mean value property of B-spline basis function is proposed and proved using mathematical induction method. Using the normalization approaches, two frameworks to solve shape optimization and identification problems for quasi-static and transient process, respectively, were developed and implemented numerically within the context of isogeometric analysis. Generalized objective functionals were used to accommodate both structural shape optimization and identification problems in arbitrary forms. The methodology and its numerical implementation were tested using benchmark problems or passive control approaches with priori known solutions. For the quasi-static case, application problems were considered where an external load was allowed to move along the surface of a structure. The shape of the structure was modified to control the time-dependent displacement of the point where the load was applied according to a pre-specified target. For the transient case, the shape optimization and identification was performed for a plunger design under a transient heating process and a thermal protection layer design for a ballistic re-entry vehicle.","isogeometric analysis; shape optimization; continuous adjoint method; quasi-static; transient heat conduction; normalization approaches; discretization/mesh-dependency","en","doctoral thesis","","","","","","","","","Aerospace Engineering","Aerospace Structures and Materials","","","",""
"uuid:71e714e4-f67c-4c21-a7ab-d19b93c0ff46","http://resolver.tudelft.nl/uuid:71e714e4-f67c-4c21-a7ab-d19b93c0ff46","Enhanced Optical Performance of BaMgAl10O17: Eu2+ Phosphor by a Novel Method of Carbon Coating","Yin, L.J. (TU Delft ChemE/Product and Process Engineering; University of Electronic Science and Technology of China); Dong, Juntao (University of Electronic Science and Technology of China); Wang, Yinping (University of Electronic Science and Technology of China); Zhang, Bi (University of Science and Technology of China); Zhou, Zheng Yang (Peking University); Jian, Xian (University of Electronic Science and Technology of China); Wu, Mengqiang (University of Electronic Science and Technology of China); Xu, Xin (University of Science and Technology of China); van Ommen, J.R. (TU Delft ChemE/Product and Process Engineering); Hintzen, H.T.J.M. (TU Delft RST/Fundamental Aspects of Materials and Energy)","","2016","Many strategies have been adopted to improve thermal degradation of phosphors. Because of the stability and high transmittance of graphene, here we report a novel method of carbon coating on BaMgAl10O17:Eu2+ (BAM) phosphor particles through chemical vapor deposition. The chemical composition, microstructure, and luminescence performance of carbon-coated BAM were characterized carefully. This coating can be controlled within 3-10 atomic layers, depending on the reaction time. Because of the decrease of surface defects and the effective weakening effect of oxidizing Eu2+ to Eu3+ after carbon coating, different layer numbers showed an obvious effect on the optical properties of carbon-coated BAM. Carbon-coated BAM phosphors had higher emission intensity and better oxidation resistance at high temperature than uncoated BAM phosphors. These results indicate that the method of carbon coating on phosphor particles is a promising way to improve the luminescence properties of other phosphors used in lighting and display devices.","","en","journal article","","","","","","Accepted Author Manuscript","","2017-01-08","","","ChemE/Product and Process Engineering","","",""
"uuid:0ef346d7-3b4a-43a4-a310-3e38b4bc5da3","http://resolver.tudelft.nl/uuid:0ef346d7-3b4a-43a4-a310-3e38b4bc5da3","Numerical investigation of the scale effect of hydrodynamic performance of the hybrid CRP pod propulsion system","Wang, Z-Z; Xiong, Y.; Wang, R.; Zong, C.-H.","","2016","","resistance & propulsion","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:f7c98131-119e-4bea-a7e0-fd54fc8a9ec0","http://resolver.tudelft.nl/uuid:f7c98131-119e-4bea-a7e0-fd54fc8a9ec0","Propagation of drought: From meteorological drought to agricultural and hydrological drought","Wang, Wen (Hohai University); Ertsen, M.W. (TU Delft Water Resources); Svoboda, Mark D. (University of Nebraska); Hafeez, Mohsin (Bureau of Meteorology Australia)","","2016","","","en","contribution to periodical","","","","","","","","","","","Water Resources","","",""
"uuid:d5cff34a-4195-4f9a-80b1-67422d990306","http://resolver.tudelft.nl/uuid:d5cff34a-4195-4f9a-80b1-67422d990306","Development of an implicit material point method for geotechnical applications","Wang, B. (TU Delft Geo-engineering); Vardon, P.J. (TU Delft Geo-engineering); Hicks, M.A. (TU Delft Geo-engineering); Chen, Z (External organisation)","","2016","","CWTS JFIS < 0.75","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:d9e3f248-06fb-48d6-a767-8589ec4b6091","http://resolver.tudelft.nl/uuid:d9e3f248-06fb-48d6-a767-8589ec4b6091","Development and Extension of An Aggregated Scale Model: Part 1 – Background to ASMITA","Townend, I (University of Southampton); Wang, Zhengbing (TU Delft Coastal Engineering); Stive, M.J.F. (TU Delft Coastal Engineering); Zhou, Z. (Hohai University)","","2016","Whilst much attention has been given to models that describe wave, tide and sediment transport processes in sufficient detail to determine the local changes in bed level over a relatively detailed representation of the bathymetry, far less attention has been given to models that consider the problem at a much larger scale (e.g. that of geomorphological elements such as a tidal flat and tidal channel). Such aggregated or lumped models tend not to represent the processes in detail but rather capture the behaviour at the scale of interest. One such model developed using the concept of an equilibrium concentration is the Aggregated Scale Morphological Interaction between Tidal basin and Adjacent coast (ASMITA). In this paper we provide some new insights into the concepts of equilibrium, and horizontal and vertical exchange that are key components of this modelling approach. In a companion paper, we summarise a range of developments that have been undertaken to extend the original model concept, to illustrate the flexibility and power of the conceptual framework. However, adding detail progressively moves the model in the direction of the more detailed process-based models and we give some consideration to the boundary between the two. Highlights
• The concept of aggregating model scales is explored and the basis of the ASMITA model is outlined in detail;
• The relationship between dispersion as used in fast-scale process-based models and the horizontal exchange used in aggregated models is explored;
• The basis for formulating suitable equilibrium relationships is explained; • Alternative ways to include advection and dispersion are examined.
swarm by dynamic actuating fields. In our approach, the
motion of micro-robots is controlled by changing the actuating
direction of a field applied to them. The time-series sequence
of actuating field’s directions can be computed automatically.
Given a target position in the domain of swarm, a governing
field is first constructed to provide optimal moving directions at
every points. Following these directions, a robot can be driven
to the target efficiently. However, when working with a crowd of
micro-robots, the optimal moving directions on different agents
can contradict with each other. To overcome this difficulty, we
develop a novel steering algorithm to compute a statistically
optimal actuating direction at each time frame. Following a
sequence of these actuating directions, a crowd of micro-robots
can be transported to the target region effectively. Our steering
strategy of swarm has been verified on a platform that generates
magnetic fields with unique actuating directions. Experimental
tests taken on aggregated magnetic micro-particles are quite
encouraging.","microrobots; mobile robots; motion control; multi-robot systems; position control; time series","en","conference paper","IEEE Society","","","","","Author accepted manuscript","","","","","Materials and Manufacturing","","",""
"uuid:df9242e6-0bed-4a54-a7c6-1cfb95b9ae3a","http://resolver.tudelft.nl/uuid:df9242e6-0bed-4a54-a7c6-1cfb95b9ae3a","Rope Caging and Grasping","Kwok, T.H.; Wan, W.; Pan, J.; Wang, C.C. (TU Delft Materials and Manufacturing); Yuan, J.; Harada, K; Chen, Y.","","2016","We present a novel method for caging grasps in this paper by stretching ropes on the surface of a 3D object. Both topology and shape of a model to be grasped has been
considered in our approach. Our algorithm can guarantee generating local minimal rings on every topological branches of a given model with the help of a Reeb graph. Cages and
grasps can then be computed from these rings, and physical experimental tests have been conducted to verify the robustness of our approach.
2-C4 olefins are important commodity chemicals usually produced by steam cracking of naphtha or fluid catalytic cracking of vacuum gas oil. The Fischer-Tropsch synthesis of lower olefins (FTO) with iron-based catalysts uses synthesis gas as an alternative feedstock. Nanostructured carbon materials are widely applied as supports for the iron nanoparticles due to their weak interaction with the metal species, facilitating the formation of catalytically active iron carbide. Numerous synthetic approaches towards carbon-supported FTO catalysts with various structures and properties have been published in recent years but structure-performance relationships remain poorly understood. We apply ordered mesoporous carbon (CMK-3) as a support material with well-defined pore structure to investigate the relationships between calcination/activation conditions and catalytic properties. After loading of iron and sodium/sulfur as the promoters, the structures and properties of the FTO catalysts are varied by using different calcination (300-1000°C) and activation (350 or 450°C) temperatures followed by FTO testing at 1 bar, 350°C, H2/CO = 1. Carbothermal reduction of iron oxides by the support material occurs at calcination temperatures of 800 or 1000°C, leading to a higher ratio of catalytically active iron(carbide) species but the catalytic activity remains low due to particle growth and blocking of the catalytically active sites with dense graphite layers. For the samples calcined at 300 and 500°C, the formation of non-blocked iron carbide can be enhanced by activation at higher temperatures, leading to higher catalytic activity. Olefin selectivities of ∼60%C in the formed hydrocarbons with methane of ∼10%C are achieved for all catalysts under FTO conditions at low CO conversion. The influence of the calcination temperature is further investigated under industrially relevant FTO conditions. Promoted CMK-3-supported catalysts obtained at low calcination temperatures of 300-500°C show stable operation for 140 h of time on stream at 10 bar, 340°C, H2/CO = 2.","","en","journal article","","","","","","","","","","","RID/TS/Technici Pool","","",""
"uuid:cc70459e-0f94-4b41-94ad-6e61f321d0b1","http://resolver.tudelft.nl/uuid:cc70459e-0f94-4b41-94ad-6e61f321d0b1","Traffic incident management in the presence of hazards","Wang, Z.; Zlatanova, S. (TU Delft Urban Data Science); Steenbruggen, John (Vrije Universiteit Amsterdam)","","2016","Traffic incidents can result in different kinds of hazards (e.g., plumes) that influence the status of road networks, therefore there is a great need for incident management in the presence of the hazards. When incidents occur, the created hazards not only affect the normal road users (make them detour or blocked), but also influence the movement of first responders. Traffic managers, who are responsible for maintaining the road safety and traffic stability, should carry out quick and effective measures to manage the incidents. In this paper, we present four issues to help people better understand the situations that could occur in the management of incidents with hazards: 1). Evacuation in the presence of hazards; 2). 3D incident management; 3). Navigation support for first responders; 4). Navigation support for road users. To address these issues, we propose a solution which combines agent technology, geo-database, hazard simulation, and traffic simulation. Further research would be needed to investigate the potentials of the proposed solution in real applications.","Incident management; Evacuation; Hazards; Navigation","en","journal article","","","","","","","","","","","Urban Data Science","","",""
"uuid:4de63c65-812d-4e09-9671-957f0474e8cb","http://resolver.tudelft.nl/uuid:4de63c65-812d-4e09-9671-957f0474e8cb","A Concealed Car Extraction Method Based on Full-Waveform LiDAR Data","Li, Chuanrong (Chinese Academy of Sciences); Zhou, Mei (Chinese Academy of Sciences); Liu, Menghua (Chinese Academy of Sciences); Ma, Lian (Chinese Academy of Sciences); Wang, J. (TU Delft Optical and Laser Remote Sensing)","","2016","Concealed cars extraction from point clouds data acquired by airborne laser scanning has gained its popularity in recent years. However, due to the occlusion effect, the number of laser points for concealed cars under trees is not enough. Thus, the concealed cars extraction is difficult and unreliable. In this paper, 3D point cloud segmentation and classification approach based on full-waveform LiDAR was presented. This approach first employed the autocorrelation G coefficient and the echo ratio to determine concealed cars areas. Then the points in the concealed cars areas were segmented with regard to elevation distribution of concealed cars. Based on the previous steps, a strategy integrating backscattered waveform features and the view histogram descriptor was developed to train sample data of concealed cars and generate the feature pattern. Finally concealed cars were classified by pattern matching. The approach was validated by full-waveform LiDAR data and experimental results demonstrated that the presented approach can extract concealed cars with accuracy more than 78.6% in the experiment areas.","","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:783456a8-77ba-4dd6-91ff-6a1862cc71e7","http://resolver.tudelft.nl/uuid:783456a8-77ba-4dd6-91ff-6a1862cc71e7","Physical Processes Driving the Morphological Evolution of the Roggenplaat Tidal Flat","de Vet, P.L.M. (TU Delft Environmental Fluid Mechanics); van Prooijen, Bram (TU Delft Environmental Fluid Mechanics); Schrijvershof, R. (Deltares); van der Werf, JJ (Deltares); Schrijver, MC (Deltares); Wang, Zhengbing (TU Delft Coastal Engineering)","","2016","The flow velocities in tidal channels are already rather complex by the presence of various tidal components, wind driven flow and estuarine circulations. An extra level of complexity is introduced when the flow on top of an intertidal
flat is considered (Le Hir, 2000). This research aims at understanding the complex flow patterns on top of a large-scale intertidal flat and on assessing the morphological consequences. The focus of this study is on the Roggenplaat, which is with an intertidal area of 14.6 km2 the largest intertidal flat
fully surrounded by channels of the Eastern Scheldt (The Netherlands, see Figure 1). The flat is subject to a mean tidal range of 2.6 m and is characterized by a typical sediment grain size of 0.25 mm. Two large tidal creeks in the Northwest
are the remainder of the merging of separate flats 80-150 years ago. Since the late 1980s, the flats in the Eastern Scheldt have been eroding severely because of the construction of a storm surge barrier and various compartment dams (Louters, 1998). A nourishment of 1.65 million m3 is planned on this flat for 2017, to compensate for its lowering. This study combines the results of an Acoustic Doppler Current Profiler (ADCP) measurement campaign with the results of a numerical model. Apart from validation material for the numerical model, the ADCP data is also analysed individually. The focus of this study is on the present-day hydrodynamics and morphodynamics of the Roggenplaat, which is essential knowledge for the design of appropriate nourishment strategies. Furthermore, physical insights achieved in this study are relevant for the understanding of other large-scale intertidal flats around the world.","intertidal flat; Eastern Scheldt; field measurements; numerical modelling","en","abstract","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:0d7b0f33-2b38-4d20-bed7-7048b2cc2427","http://resolver.tudelft.nl/uuid:0d7b0f33-2b38-4d20-bed7-7048b2cc2427","Net sediment transport by tidal asymmetry in the hyper-turbid Ems River","Winterwerp, J.C. (TU Delft Environmental Fluid Mechanics); Vroom, J. (Deltares); Wang, Zhengbing (TU Delft Coastal Engineering); Krebs, Martin (EMS Waterway Administration)","","2016","","tidal asymmetry; hyper-turbidity; Ems River","en","abstract","","","","","","","","","","","Environmental Fluid Mechanics","","",""
"uuid:2ab5614d-e0d7-4148-91bd-aeacf4793356","http://resolver.tudelft.nl/uuid:2ab5614d-e0d7-4148-91bd-aeacf4793356","Optimal lane change times and accelerations of autonomous and connected vehicles","Wang, M. (TU Delft Transport and Planning; TU Delft Biomechatronics & Human-Machine Control); Hoogendoorn, S.P. (TU Delft Transport and Planning); Daamen, W. (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning); Happee, R. (TU Delft OLD Intelligent Vehicles & Cognitive Robotics)","","2016","This contribution puts forward a flexible approach to model the decision-making or design controller for automated driving systems, where tactical-level lane change decisions and control-level accelerations are jointly evaluated based on iteratively solving an online optimization problem. The key idea is that automated vehicles determine lane change times and accelerations in the predicted future to minimize an objective function representing multiple criteria of driving safety, efficiency and comfort. The interactions between controlled vehicles and surrounding vehicles are captured in the objective function. The approach can be applied to model non-cooperative decision-making of autonomous vehicles with optimization of own cost and cooperative behavior of connected vehicles with joint optimization of the collective cost. The problem is formulated as a differential game where automated vehicles make decisions based on the expected behavior of surrounding vehicles. An efficient numerical solution algorithm is used to solve problem. The proposed model performance is demonstrated via numerical examples. The results show that the proposed approach can produce efficient lane-changing maneuvers while obeying safety and comfort requirements. Particularly, the approach generates optimal lane change times and accelerations in the predicted future, including strategic overtaking and cooperative merging scenarios.","Acceleration (Mechanics); Algorithms; Decision making; Intelligent vehicles; Lane changing; Optimization","en","conference paper","Transportation Research Board (TRB)","","","","","Accepted Author Manuscript","","","","Transport and Planning","Transport and Planning","","",""
"uuid:927678db-9839-492e-97a2-55821ff9828d","http://resolver.tudelft.nl/uuid:927678db-9839-492e-97a2-55821ff9828d","Improved ADRC for a Maglev planar motor with a concentric winding structure","Kou, Baoquan (Harbin Institute of Technology); Xing, Feng (Harbin Institute of Technology); Zhang, Chaoning; Zhang, L. (TU Delft Pattern Recognition and Bioinformatics; School of Electrical Engineering and Automation; Harbin Institute of Technology); Zhou, Yiheng (Harbin Institute of Technology); Wang, Tiecheng (Harbin Institute of Technology)","","2016","In the semiconductor industry, positioning accuracy and acceleration are critical parameters. To improve the acceleration speed of a motor, this paper proposes the moving-coil maglev planar motor with a concentric winding structure. The coordinate system has been built for the multiple degrees of freedom movement system. The Lorenz force method has been applied to solve its electromagnetic model. The real-time solving of the generalized inverse matrix of factors can realize the decoupling of the winding current. When the maglev height changes, the electromagnetic force and torque decreases exponentially with the increase of the air gap. To decrease the influence on control system performance by the internal model change and the external disturbance, this paper proposes an improved active disturbance rejection control (ADRC) to design the controller. This new controller overcomes the jitter phenomenon due to the turning point for the traditional ADRC, thus it is more suitable for the maglev control system. The comparison between ADRC and the improved ADRC has been conducted, the result of which shows the improved ADRC has greater robustness.","Concentric winding; Improved ADRC; Maglev planar motor; Robustness","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:47c7a171-92af-4b55-8d7e-7b0a476ce88e","http://resolver.tudelft.nl/uuid:47c7a171-92af-4b55-8d7e-7b0a476ce88e","Quality assessment and comparison of smartphone, airborne and leica c10 laser scanner based point clouds","Sirmacek, B. (TU Delft Optical and Laser Remote Sensing); Lindenbergh, R.C. (TU Delft Optical and Laser Remote Sensing); Wang, J. (TU Delft Optical and Laser Remote Sensing)","","2016","3D urban models are valuable for urban map generation, environment monitoring, safety planning and educational purposes. For 3D measurement of urban structures, generally airborne laser scanning sensors or multi-view satellite images are used as a data source. However, close-range sensors (such as terrestrial laser scanners) and low cost cameras (which can generate point clouds based on photogrammetry) can provide denser sampling of 3D surface geometry. Unfortunately, terrestrial laser scanning sensors are expensive and trained persons are needed to use them for point cloud acquisition. A potential effective 3D modelling can be generated based on a low cost smartphone sensor. Herein, we show examples of using smartphone camera images to generate 3D models of urban structures. We compare a smartphone based 3D model of an example structure with a terrestrial laser scanning point cloud of the structure. This comparison gives us opportunity to discuss the differences in terms of geometrical correctness, as well as the advantages, disadvantages and limitations in data acquisition and processing. We also discuss how smartphone based point clouds can help to solve further problems with 3D urban model generation in a practical way. We show that terrestrial laser scanning point clouds which do not have color information can be colored using smartphones. The experiments, discussions and scientific findings might be insightful for the future studies in fast, easy and low-cost 3D urban model generation field.","3D City Models; Point Clouds; Terrestrial Laser Scanning (TLS); Structure from Motion (SfM); Multi-view Photogrammetry; Low-cost sensors","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:dc6e2971-2d99-4741-89de-892a2687f242","http://resolver.tudelft.nl/uuid:dc6e2971-2d99-4741-89de-892a2687f242","Is “Morphodynamic Equilibrium” an oxymoron?","Zhou, Zeng; Coco, Giovanni; Townend, IH; Olabarrieta, Maitane; van der Wegen, M.; Gong, Zheng; D’Alpaos, Andrea; Gao, Shu; Jaffe, Bruce; Gelfenbaum, Guy; He, Qing; Wang, Yaping; Lanzoni, Stefano; Wang, Zhengbing (TU Delft Coastal Engineering); Winterwerp, J.C. (TU Delft Environmental Fluid Mechanics); Zhang, Changkuan","","2016","Morphodynamic equilibrium is a widely adopted yet elusive concept in the field of geomorphology of coasts, rivers and estuaries. Based on the Exner equation, an expression of mass conservation of sediment, we distinguish three types of equilibrium defined as static and dynamic, of which two different types exist. Other expressions such as statistical and quasi-equilibrium which do not strictly satisfy the Exner conditions are also acknowledged for their practical use. The choice of a temporal scale is imperative to analyse the type of equilibrium. We discuss the difference between morphodynamic equilibrium in the ""real world"" (nature) and the ""virtual world"" (model). Modelling studies rely on simplifications of the real world and lead to understanding of process interactions. A variety of factors affect the use of virtual-world predictions in the real world (e.g., variability in environmental drivers and variability in the setting) so that the concept of morphodynamic equilibrium should be mathematically unequivocal in the virtual world and interpreted over the appropriate spatial and temporal scale in the real world. We draw examples from estuarine settings which are subject to various governing factors which broadly include hydrodynamics, sedimentology and landscape setting. Following the traditional ""tide-wave-river"" ternary diagram, we summarize studies todate that explore the ""virtual world"", discuss the type of equilibrium reached and how it relates to the real world.","","en","journal article","","","","","","","","2019-01-01","","","Coastal Engineering","","",""
"uuid:e50fc686-e88b-492b-ba81-4e10aef14ed9","http://resolver.tudelft.nl/uuid:e50fc686-e88b-492b-ba81-4e10aef14ed9","Screening criteria for ILs used in NH3 based absorption heat pump systems","Wang, M. (TU Delft Engineering Thermodynamics); Infante Ferreira, C.A. (TU Delft Engineering Thermodynamics)","Groll, Eckhard (editor)","2016","This paper describes a properties-optimization work for the working fluids in NH3 / ionic liquid (ILs) based single-effect absorption heat pumps. The optimum parameters of the IL can be used as criteria in screening task-specified ILs, which play the role of absorbents, in absorption heat pumps. First, a 8-parameter thermodynamic model to calculate performances of a single-effect absorption heat pump cycle was proposed, which is based on the non-random two-liquid (NRTL) activity coefficient model for the vapor pressure and a linear function for the heat capacity. Then, experimental data on the vapor-liquid equilibrium (VLE) of solutions and heat capacities of the pure ILs were reviewed and fitted to obtain ranges of those parameters. Within certain limits, the values of parameters were optimized in the following step using the above proposed mode. The objective is a maximum system performance. The optimized ILs have low molecular weights, low specific heats and have high absorption capabilities.","absorption cycle; heat pump; ILs; NH3","en","conference paper","Purdue University","","","","","Paper no. 1690 http://docs.lib.purdue.edu/iracc/1690","","","","","Engineering Thermodynamics","","",""
"uuid:70239986-71a7-4e77-83d1-d5fe85b18acf","http://resolver.tudelft.nl/uuid:70239986-71a7-4e77-83d1-d5fe85b18acf","Delay-compensating strategy to enhance string stability of adaptive cruise controlled vehicles","Wang, M. (TU Delft Transport and Planning); Hoogendoorn, S.P. (TU Delft Transport and Planning); Daamen, W. (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning); Shyrokau, B. (TU Delft OLD Intelligent Vehicles & Cognitive Robotics); Happee, R. (TU Delft OLD Intelligent Vehicles & Cognitive Robotics)","","2016","A novel strategy to enhance string stability of autonomous vehicles with sensor delay and actuator lag is proposed based on a model predictive control framework. To compensate sensor delay, the approach entails estimating the (unknown) system state at the current time using the system state in a previous time, the applied control history and a system dynamics model. The actuator lag is compensated by including the lag in the state prediction model. The mathematical framework shows that without the anticipation strategy, sensor delay leads to a worse estimate of the initial condition for the optimal control problem and actuator lag increases the mismatch between the system state prediction model and the actual system behaviour. Simulation verified that sensor delay and actuator lag degrade string stability of platoons. The proposed anticipatory control strategy shows clear benefits in improving autonomous vehicle string stability and hence has potential to enhance traffic flow stability","","en","journal article","","","","","","","","2018-01-01","","Transport and Planning","Transport and Planning","","",""
"uuid:98d5dae7-1bbc-4237-9668-2c631812f4e1","http://resolver.tudelft.nl/uuid:98d5dae7-1bbc-4237-9668-2c631812f4e1","Coarse point cloud registration by EGI matching of voxel clusters","Wang, J. (TU Delft Optical and Laser Remote Sensing; Chinese Academy of Sciences); Lindenbergh, R.C. (TU Delft Optical and Laser Remote Sensing); Shen, Y. (TU Delft Optical and Laser Remote Sensing; Hohai University); Menenti, M. (TU Delft Optical and Laser Remote Sensing)","","2016","Laser scanning samples the surface geometry of objects efficiently and records versatile information as point clouds. However, often more scans are required to fully cover a scene. Therefore, a registration step is required that transforms the different scans into a common coordinate system. The registration of point clouds is usually conducted in two steps, i.e. coarse registration followed by fine registration. In this study an automatic marker-free coarse registration method for pair-wise scans is presented. First the two input point clouds are re-sampled as voxels and dimensionality features of the voxels are determined by principal component analysis (PCA). Then voxel cells with the same dimensionality are clustered. Next, the Extended Gaussian Image (EGI) descriptor of those voxel clusters are constructed using significant eigenvectors of each voxel in the cluster. Correspondences between clusters in source and target data are obtained according to the similarity between their EGI descriptors. The random sampling consensus (RANSAC) algorithm is employed to remove outlying correspondences until a coarse alignment is obtained. If necessary, a fine registration is performed in a final step. This new method is illustrated on scan data sampling two indoor scenarios. The results of the tests are evaluated by computing the point to point distance between the two input point clouds. The presented two tests resulted in mean distances of 7.6 mm and 9.5 mm respectively, which are adequate for fine registration.","Laser scanning; Point clouds; Voxels; Clustering; Eigenvalues; Registration","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:65c6b86f-b571-4ed6-8d03-97bd57e92c53","http://resolver.tudelft.nl/uuid:65c6b86f-b571-4ed6-8d03-97bd57e92c53","Design and analysis of full range adaptive cruise control with integrated collision a voidance strategy","Mullakkal-Babu, F.A. (TU Delft Transport and Planning); Wang, M. (TU Delft Transport and Planning); van Arem, B. (TU Delft Transport and Planning); Happee, R. (TU Delft OLD Intelligent Vehicles & Cognitive Robotics)","Rosetti, R. (editor); Wolf, D. (editor)","2016","Current Full Range Adaptive Cruise Control (FRACC) systems switch between separate adaptive cruise control and collision avoidance systems. This can lead to jerky responses and discomfort during the transition between the two control modes. We propose a Full Range Adaptive Cruise Control (FRACC) design integrating adaptive cruise control and collision avoidance into a single non-linear mathematical formulation. The proposed FRACC responds to a velocityerror using a sigmoidal function of forward spacing. Mathematical properties of the controller, in particular string stability, are examined. Simulation experiments demonstrate that the controller yields smooth and safe responses in typical highway scenarios, including hard-braking and cut-in scenarios. Results also show a clear advantage of the proposed controller in string stability performance with reference to a state-of-The-Art controller.","","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Accepted Author Manuscript","","","","Transport and Planning","Transport and Planning","","",""
"uuid:5d14299e-64d9-4d1c-8f7f-dc7521d6c7ac","http://resolver.tudelft.nl/uuid:5d14299e-64d9-4d1c-8f7f-dc7521d6c7ac","Computing equation of state parameters of gases from Monte Carlo simulations","Ramdin, M. (TU Delft Engineering Thermodynamics); Becker, T. (TU Delft Engineering Thermodynamics); Jamali, S.H. (TU Delft Engineering Thermodynamics); Wang, M. (TU Delft Engineering Thermodynamics); Vlugt, T.J.H. (TU Delft Engineering Thermodynamics)","","2016","Monte Carlo (MC) simulations in ensembles with a fixed chemical potential or fugacity, for example the grand-canonical or the osmotic ensemble, are often used to compute phase equilibria. Chemical potentials can be computed either with an equation of state (EoS) or from molecular simulations. The accuracy of the computed chemical potentials depends on the quality of the (critical) parameters used in the EoS and the applied force field in the simulations. We investigated the consistency of both approaches for computing fugacities of the industrially relevant gases CO2, CH4, CO, H2, N2, and H2S. The critical temperature (Tc), pressure (Pc), and acentric factors (ω) of these gases are computed from MC simulations in the Gibbs ensemble. The effect of cutoff radius and tail corrections on the computed values of Tc, Pc, and ω is investigated. In addition, MC simulations in the Gibbs ensemble are used to compute the VLE of the 15 possible binary systems comprising the gases CO2, CH4, CO, H2, N2, and H2S, and the ternary systems CO2/CH4/H2S and CO2/CO/H2. Binary interaction parameters (kij) of these natural/synthesis gas mixtures are obtained by fitting the Peng-Robinson (PR) EoS to the binary VLE data from the MC simulations. The computed properties from the MC simulations are compared with the PR EoS, the GERG EoS, and experimental results. The MC results show that including tail corrections in the simulations is crucial to obtain accurate critical properties. The force fields used for the gases can reproduce the fugacities of the gases within 5% of the experimental data. The dew-point curves of all the 15 binaries were predicted correctly by the MC simulations, but the bubble-point curves for the systems H2/CO, CH4/H2, H2S/N2, and H2S/CO significantly deviate from the experiments.","Binary interaction parameter; Equation of state; Molecular simulation; Natural gas; Synthesis gas","en","journal article","","","","","","Accepted Author Manuscript","","2018-06-07","","","Engineering Thermodynamics","","",""
"uuid:b0cf30de-7d21-4671-9491-d0f8dd965804","http://resolver.tudelft.nl/uuid:b0cf30de-7d21-4671-9491-d0f8dd965804","Gamma-Retrovirus integration marks cell type-specific cancer genes: A novel profiling tool in cancer genomics","Gilroy, Kathryn L. (University of Glasgow); Terry, Anne (University of Glasgow); Naseer, Asif (University of Glasgow; Khyber Medical University); de Ridder, J. (TU Delft Pattern Recognition and Bioinformatics); Allahyar, A. (TU Delft Pattern Recognition and Bioinformatics); Wang, Weiwei (University of Alberta); Carpenter, Eric (University of Alberta); Mason, Andrew (University of Alberta); Wong, Gane K.S. (University of Alberta); Cameron, Ewan R. (University of Glasgow); Kilbey, Anna (University of Glasgow); Neil, James C. (University of Glasgow)","","2016","Retroviruses have been foundational in cancer research since early studies identified protooncogenes as targets for insertional mutagenesis. Integration of murine gamma-retroviruses into the host genome favours promoters and enhancers and entails interaction of viral integrase with host BET/bromodomain factors. We report that this integration pattern is conserved in feline leukaemia virus (FeLV), a gamma-retrovirus that infects many human cell types. Analysis of FeLV insertion sites in the MCF-7 mammary carcinoma cell line revealed strong bias towards active chromatin marks with no evidence of significant post-integration growth selection. The most prominent FeLV integration targets had little overlap with the most abundantly expressed transcripts, but were strongly enriched for annotated cancer genes. A meta-analysis based on several gamma-retrovirus integration profiling (GRIP) studies in human cells (CD34+, K562, HepG2) revealed a similar cancer gene bias but also remarkable cell-type specificity, with prominent exceptions including a universal integration hotspot at the long non-coding RNA MALAT1. Comparison of GRIP targets with databases of super-enhancers from the same cell lines showed that these have only limited overlap and that GRIP provides unique insights into the upstream drivers of cell growth. These observations elucidate the oncogenic potency of the gamma-retroviruses and support the wider application of GRIP to identify the genes and growth regulatory circuits that drive distinct cancer types.","","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:f9d77304-60c2-4e61-9c42-06c889c7e270","http://resolver.tudelft.nl/uuid:f9d77304-60c2-4e61-9c42-06c889c7e270","The need for high resolution precipitation data to improve urban drainage modelling","Ten Veldhuis, J.A.E.; Ochoa-Rodriguez, S.; Gires, A.; van Assel, J.; Ichiba, A.; Kroll, S.; Wang, L.; Tchiguirinskaia, I.; Schertzer, D.; Willems, P.","","2015","Cities are particularly vulnerable to rainfall-generated floods that are typically characterised by their rapid onset and localised nature. This implies that precipitation and catchment information need to be available at high resolution to reliably predict hydrological response and potential flooding. On the contrary, urban areas constitute a major knowledge gap as most flood risk studies have concentrated on natural basins and records of rain gauges and water level gauges in cities are scarce. While increase in intense precipitation as a result of climate change is expected in many areas around the world, it is at present not possible to assess how this will affect urban pluvial flood risk. Collection of reliable, high resolution data in cities needs to start urgently to build up datasets in support of urban flood risk assessment and to enable detection of changes in flood risk whether these are induced by climate change, urbanisation or other future developments. This study shows how implementation of polarimetric X-band radar can contribute to filling the knowledge gap of flood risk quantification in cities.","","en","conference paper","International Union of Geodesy and Geophysics","","","","","","","","Civil Engineering and Geosciences","Water Management","","","",""
"uuid:0dc74d8b-4c57-42b1-8020-72f0f60cf0fc","http://resolver.tudelft.nl/uuid:0dc74d8b-4c57-42b1-8020-72f0f60cf0fc","The need for high resolution precipitation data to improve urban drainage modelling","Ten Veldhuis, J.A.E.; Ochoa-Rodriguez, S.; Gires, A.; Van Assel, J.; Ichiba, A.; Kroll, S.; Wang, L.; Tchiguirinskaia, I.; Schertzer, D.; Willems, P.","","2015","In this study high resolution precipitation data are used, derived from polarimetric X-band radar at 100 m, 1 min resolution. The data are used to study the impact of different space-time resolutions of rainfall input on urban hydrodynamic modelling response for 9 storms, in 7 urban catchments. The results show that hydrodynamic response behaviour was highly sensitive to variations in rainfall space-time resolution, more strongly so for changes in temporal than in spatial resolution. Under- and overestimations of flow peaks amounted to up to 100% with respect to the original 100 m, 1 minute rainfall input.","rainfall space-time resolution; radar rainfall; urban hydrology; urban hydrological response modelling","en","conference paper","IWA","","","","","","","","Civil Engineering and Geosciences","Water Management","","","",""
"uuid:79689f0a-cb02-46d8-95eb-0743397a1f48","http://resolver.tudelft.nl/uuid:79689f0a-cb02-46d8-95eb-0743397a1f48","Effect of steering model fidelity on subjective evaluation of truck steering feel","Shyrokau, B.; Loof, J.; Stroosma, O.; Wang, M.; Happee, R.","","2015","The steering behaviour in a driving simulator has a significant influence on a driving realism. This study investigates the influence of the complexity of a steering-system model on the subjective assessment of truck steering feel in on-centre handling. Ten subjects drove a highway task with and without lateral wind disturbance with 4 steering-system model variants. The results show that detailed modelling of the steering system plays a significant role in the subjective assessment of truck steering feel, and has a corresponding effect on objective steering performance.","truck steering wheel; steering model; subjective assessment; on-centre handling; driving simulator","en","conference paper","Max Planck Institute for Biological Cybernetics","","","","","","","","Mechanical, Maritime and Materials Engineering","Biomechanical Engineering","","","",""
"uuid:3ef0805f-3446-4398-8807-d01dd12fdab0","http://resolver.tudelft.nl/uuid:3ef0805f-3446-4398-8807-d01dd12fdab0","Intercomparison of methods of coupling between convection and large-scale circulation: 1. Comparison over uniform surface conditions","Daleu, C. L. (University of Reading); Plant, R. S. (University of Reading); Woolnough, S. J. (University of Reading); Sessions, S. (New Mexico Tech); Herman, M. J. (New Mexico Tech); Sobel, A. (Columbia University); Wang, S. (Columbia University); Kim, D. (University of Washington); Cheng, A. (NASA Langley Research Center); Bellon, G. (The University of Auckland); Peyrille, P. (Meteo France); Ferry, F. (Meteo France); Siebesma, A.P. (TU Delft Atmospheric Physics; TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI)); Van Ulft, L. (Royal Netherlands Meteorological Institute (KNMI))","","2015","As part of an international intercomparison project, a set of single-column models (SCMs) and cloud-resolving models (CRMs) are run under the weak-temperature gradient (WTG) method and the damped gravity wave (DGW) method. For each model, the implementation of the WTG or DGW method involves a simulated column which is coupled to a reference state defined with profiles obtained from the same model in radiative-convective equilibrium. The simulated column has the same surface conditions as the reference state and is initialized with profiles from the reference state. We performed systematic comparison of the behavior of different models under a consistent implementation of the WTG method and the DGW method and systematic comparison of the WTG and DGW methods in models with different physics and numerics. CRMs and SCMs produce a variety of behaviors under both WTG and DGW methods. Some of the models reproduce the reference state while others sustain a large-scale circulation which results in either substantially lower or higher precipitation compared to the value of the reference state. CRMs show a fairly linear relationship between precipitation and circulation strength. SCMs display a wider range of behaviors than CRMs. Some SCMs under the WTG method produce zero precipitation. Within an individual SCM, a DGW simulation and a corresponding WTG simulation can produce different signed circulation. When initialized with a dry troposphere, DGW simulations always result in a precipitating equilibrium state. The greatest sensitivities to the initial moisture conditions occur for multiple stable equilibria in some WTG simulations, corresponding to either a dry equilibrium state when initialized as dry or a precipitating equilibrium state when initialized as moist. Multiple equilibria are seen in more WTG simulations for higher SST. In some models, the existence of multiple equilibria is sensitive to some parameters in the WTG calculations.","damped gravity wave; large-scale parameterized dynamics; multiple equilibria; tropical convection; weak-temperature gradient","en","journal article","","","","","","","","","","","Atmospheric Physics","","",""
"uuid:b34ba88d-842f-4691-85fb-b738ea107b65","http://resolver.tudelft.nl/uuid:b34ba88d-842f-4691-85fb-b738ea107b65","Do intertidal flats ever reach equilibrium?","Maan, D.C.; van Prooijen, B.C.; Wang, Z.B.; de Vriend, H.J.","","2015","Various studies have identified a strong relation between the hydrodynamic forces and the equilibrium profile for intertidal flats. A thorough understanding of the interplay between the hydrodynamic forces and the morphology, however, concerns more than the equilibrium state alone. We study the basic processes and feedback mechanisms underlying the long-term behavior of the intertidal system, restricting ourselves to unvegetated intertidal flats that are controlled by cross-shore tidal currents and wind waves and applying a 1-D cross-shore morphodynamic model. The results indicate that by an adjustment of the profile slope and shape, an initial imbalance between deposition and erosion is minimized within a few decades. What follows is a state of long-term seaward progradation or landward retreat of the intertidal flat, in which the cross-shore profile shape is largely maintained and the imbalance between deposition and erosion is not further reduced. These long-term trends can be explained by positive feedbacks from the morphology onto the hydrodynamic forces over the flat: initial accretion (erosion) decreases (increases) the shear stresses over the flat, which induces further accretion (erosion). This implies that a static equilibrium state cannot exist; the flat either builds out or retreats. The modeled behavior is in accordance with observations in the Yangtze Estuary. To treat these unbalanced systems with a one-dimensional numerical model, we propose a moving (Lagrangian) framework in which a stable cross-sectional shape and progradation speed can be derived for growing tidal flats, as a function of the wave climate and the sediment concentration in deeper water.","","en","journal article","American Geophysical Union (AGU)","","","","","","","2016-05-30","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:b13ac9b3-7602-412f-bb1d-0cd6810bf246","http://resolver.tudelft.nl/uuid:b13ac9b3-7602-412f-bb1d-0cd6810bf246","A measurement study of DNSSEC misconfigurations","Van Adrichem, N.L.M.; Blenn, N.; Reyes-Lua, A.; Wang, X.; Wasif, M.; Fatturrahman, F.; Kuipers, F.A.","","2015","DNSSEC offers protection against spoofing of DNS data by providing origin authentication, ensuring data integrity and authentication of non-existence by using public-key cryptography. Although the relevance of securing a technology as crucial to the Internet as DNS is obvious, the DNSSEC implementation increases the complexity of the deployed DNS infrastructure, which may result in misconfiguration. In this article, we measure and analyze the misconfigurations for domains in six zones (.bg, .br, .co, .com, .nl and .se). Furthermore, we categorize these misconfigurations and provide an explanation for their possible causes. Finally, we evaluate the effects of misconfigurations on the reachability of a zone’s network. Our results show that, although progress has been made in the implementation of DNSSEC, over 4 % of evaluated domains show misconfigurations. The domains with the most frequently appearing misconfiguration are often hosted at a very limited set of hosting providers. Of these misconfigured domains, almost 75 % were unreachable from a DNSSEC-aware resolver. This illustrates that although the authorities of a domain may think their DNS is secured, it is in fact not. Worse still, misconfigured domains are at risk of being unreachable from the clients who care about and implement DNSSEC verification, while the publisher may remain unaware of the error and its consequences.","DNS; DNSSEC; Domain Name System; authentication; integrity; misconfiguration; validation; signatures; error; unreachability; OA-Fund TU Delft","en","journal article","Springer","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Intelligent Systems","","","",""
"uuid:00ed4577-fc6c-497f-aad7-211844fec04d","http://resolver.tudelft.nl/uuid:00ed4577-fc6c-497f-aad7-211844fec04d","Effect of Prior Knowledge on Site-Specific Selection of Regression Model for Characterization of Geotechnical Properties","Aladejare, A.E.; Wang, Y.","","2015","During geotechnical site characterization, many geotechnical properties might be difficult to measure directly and have to be estimated using indirect measurement and regression models. For example, when there is no possibility of direct compression test, geotechnical engineers and practitioners may utilize regression models (i.e. equations) to estimate the uniaxial compressive strength, UCS, of rock from point load index, Is(50). However, there are many equations relating Is(50) to UCS in the literature. This leads to the problem of how to select the most appropriate model for a particular rock deposit out of the numerous models available. This study presents a method that rationally compares different regression models and selects the most appropriate model for a specific site or deposit considered herein. The most appropriate model is selected using only a limited number of site-specific Is(50) data. The selected model is then used in a Bayesian framework to integrate the prior knowledge about UCS with the limited number of site-specific Is(50) data available for probabilistic characterization of UCS. The approach is shown to perform properly, particularly when the prior knowledge reflects information from the site.","regression model; geotechnical properties; occurrence probability; probabilistic characterization; prior knowledge","en","conference paper","","","","","","","","","","","","","",""
"uuid:532b2ac0-9df1-4b41-98c7-daf9855a7b92","http://resolver.tudelft.nl/uuid:532b2ac0-9df1-4b41-98c7-daf9855a7b92","Application of modified-alginate encapsulated carbonate producing bacteria in concrete: A promising strategy for crack self-healing","Wang, J.; Mignon, A.; Snoeck, D.; Wiktor, V.A.C.; Van Vliergerghe, S.; Boon, N.; De Belle, N.","","2015","","modified-alginate hydrogel; B. sphaericus spores; bacterialCaCO3; in situ activity; oxygen consumption; crackself-healing","en","journal article","Frontiers","","","","","","","","Civil Engineering and Geosciences","Structural Engineering","","","",""
"uuid:5c80616a-87ba-478d-8428-45f807f473f3","http://resolver.tudelft.nl/uuid:5c80616a-87ba-478d-8428-45f807f473f3","A network approach for power grid robustness against cascading failures","Wang, X.; Koc, Y.; Kooij, R.E.; Van Mieghem, P.","","2015","Cascading failures are one of the main reasons for blackouts in electrical power grids. Stable power supply requires a robust design of the power grid topology. Currently, the impact of the grid structure on the grid robustness is mainly assessed by purely topological metrics, that fail to capture the fundamental properties of the electrical power grids such as power flow allocation according to Kirchhoff’s laws. This paper deploys the effective graph resistance as a metric to relate the topology of a grid to its robustness against cascading failures. Specifically, the effective graph resistance is deployed as a metric for network expansions (by means of transmission line additions) of an existing power grid. Four strategies based on network properties are investigated to optimize the effective graph resistance, accordingly to improve the robustness, of a given power grid at a low computational complexity. Experimental results suggest the existence of Braess’s paradox in power grids: bringing an additional line into the system occasionally results in decrease of the grid robustness. This paper further investigates the impact of the topology on the Braess’s paradox, and identifies specific sub-structures whose existence results in Braess’s paradox in power grids. Careful assessment of the design and expansion choices of grid topologies incorporating the insights provided by this paper optimizes the robustness of a power grid, while avoiding the Braess’s paradox in the system.","","en","conference paper","RNDM","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Network Architectures and Services","","","",""
"uuid:ea283396-728d-4074-8aa2-c788077b6ed3","http://resolver.tudelft.nl/uuid:ea283396-728d-4074-8aa2-c788077b6ed3","Automated large scale parameter extraction of road-side trees sampled by a laser mobile mapping system","Lindenbergh, R.C.; Berthold, D.; Sirmacek, B.; Herrero-Huerta, M.; Wang, J.; Ebersbach, D.","","2015","In urbanized Western Europe trees are considered an important component of the built-up environment. This also means that there is an increasing demand for tree inventories. Laser mobile mapping systems provide an efficient and accurate way to sample the 3D road surrounding including notable roadside trees. Indeed, at, say, 50 km/h such systems collect point clouds consisting of half a million points per 100m. Method exists that extract tree parameters from relatively small patches of such data, but a remaining challenge is to operationally extract roadside tree parameters at regional level. For this purpose a workflow is presented as follows: The input point clouds are consecutively downsampled, retiled, classified, segmented into individual trees and upsampled to enable automated extraction of tree location, tree height, canopy diameter and trunk diameter at breast height (DBH). The workflow is implemented to work on a laser mobile mapping data set sampling 100 km of road in Sachsen, Germany and is tested on a stretch of road of 7km long. Along this road, the method detected 315 trees that were considered well detected and 56 clusters of tree points were no individual trees could be identified. Using voxels, the data volume could be reduced by about 97 % in a default scenario. Processing the results of this scenario took 2500 seconds, corresponding to about 10 km/h, which is getting close to but is still below the acquisition rate which is estimated at 50 km/h.","big data; laser mobile mapping; tree parameters; urban; voxels","en","conference paper","ISPRS","","","","","","","","Civil Engineering and Geosciences","Geoscience & Remote Sensing","","","",""
"uuid:e0f4dba8-11a4-429a-92ce-9c0a50951325","http://resolver.tudelft.nl/uuid:e0f4dba8-11a4-429a-92ce-9c0a50951325","Evaluating voxel enabled scalable intersection of large point clouds","Wang, J.; Lindenbergh, R.C.; Menenti, M.","","2015","Laser scanning has become a well established surveying solution for obtaining 3D geo-spatial information on objects and environment. Nowadays scanners acquire up to millions of points per second which makes point cloud huge. Laser scanning is widely applied from airborne, carborne and stable platforms, resulting in point clouds obtained at different attitudes and with different extents. Working with such different large point clouds makes the determination of their overlapping area necessary but often time consuming. In this paper, a scalable point cloud intersection determination method is presented based on voxels. The method takes two overlapping point clouds as input. It consecutively resamples the input point clouds according to a preset voxel cell size. For all non-empty cells the center of gravity of the points in contains is computed. Consecutively for those centers it is checked if they are in a voxel cell of the other point cloud. The same process is repeated after interchanging the role of the two point clouds. The quality of the results is evaluated by the distance to the pints from the other data set. Also computation time and quality of the results are compared for different voxel cell sizes. The results are demonstrated on determining he intersection between an airborne and carborne laser point clouds and show that the proposed method takes 0.10%, 0.15%, 1.26% and 14.35% of computation time compared the the classic method when using cell sizes of of 10, 8, 5 and 3 meters respectively.","voxel; laser scanning; point clouds; intersection area","en","conference paper","ISPRS","","","","","","","","Civil Engineering and Geosciences","Geoscience & Remote Sensing","","","",""
"uuid:ec4a5764-561d-4960-b070-ee4c382c4a23","http://resolver.tudelft.nl/uuid:ec4a5764-561d-4960-b070-ee4c382c4a23","IQPC 2015 track: Tree separation and classification in mobile mapping lidar data","Gorte, B.G.H.; Oude Elberink, S.; Sirmacek, B.; Wang, J.","","2015","The European FP7 project IQmulus yearly organizes several processing contests, where submissions are requested for novel algorithms for point cloud and other big geodata processing. This paper describes the set-up and execution of a contest having the purpose to evaluate state-of-the-art algorithms for Mobile Mapping System point clouds, in order to detect and identify (individual) trees. By the nature of MMS these are trees in the vicinity of the road network (rather than in forests). Therefore, part of the challenge is distinguishing between trees and other objects, such as buildings, street furniture, cars etc. Three submitted segmentation and classification algorithms are thus evaluated.","mobile mapping systems; lidar; tree separation; classification","en","conference paper","ISPRS","","","","","","","","Civil Engineering and Geosciences","Geoscience & Remote Sensing","","","",""
"uuid:2c595513-a149-4d0f-b45a-be192885efc4","http://resolver.tudelft.nl/uuid:2c595513-a149-4d0f-b45a-be192885efc4","Active Vision for Humanoid Robots","Wang, X.","Jonker, P.P. (promotor)","2015","Human perception is an active process. By altering its viewpoint rather than passively observing surroundings and by operating on sequences of images rather than on a single frame, the human visual system has the ability to explore the most relevant information based on knowledge, therefore when growing up a human is able to develop cognitive perception. Comparably, for humanoid robots to develop cognitive perception, active vision is indispensable. Humanoid robot research has already nearly half a century history. There are approximately 2000 research papers on active vision published during 1986?2010 that covered a large range of research fields in robotics. Nowadays, the new trend is to use a stereo setup or a Kinect with neck movements to realize active vision. However, human perception is a combination of eyes and neck movement. In order to design such an advanced humanoid active vision system, eye movements with biological inspiration similar to human eyes should be taken into consideration. Depth perception based on pure image information can then be obtained without utilizing any advanced sensors. This thesis presents a complete active vision system with 4 degrees of freedom that works in a similar way as human vision. It is composed of the following parts: 1. The mechanical design has 4 motors with independent vergence angle control, one tilt motor for both eyes and one pan motor for the neck. 2. The controllers simulate the eye movements as humans: saccade eye movements, pursuit eye movements, vestibulo-ocular reflex (VOR) eye movements and vergence eye movements, where motor positions and velocities are controlled with input from an Inertia Measurement Unit (IMU). 3. An optimal feature selection mechanism which is based on various properties of objects is applied before tracking. 4. In order to smoothly pursue and learn an object from different perspectives, three different trackers are used: a color based tracker, an AR marker based tracker for testing, and a robust online tracker. 5. A saliency detector segments the most dominant objects from the scenes and a robust online tracker provides refined segmentations. As a result, the robots have a self-explorative ability for unknown environments. 6. Owing to vergent eyes moving at different angles, intrinsic calibration as well as extrinsic calibration is required to ensure the accuracy of 3D perception. Here the motor positions are utilized together with a robust M-Estimator to recover the geometry between two eyes. 7. Humans utilize multiple cues for depth perception. Depth perception is strongly related to eye movements. Multi-mode depth perception is applied to perceive environment and objects in 3D for further vision tasks such as object recognition, and object grasping. The realized system works within real-time constraints and with low cost cameras and motors. Therefore it provides an affordable solution for industrial applications. In conclusion, active vision can be applied to various applications and it is a rapid-growing research domain. This thesis and its proposed vision system provides an insight into the research field of active humanoid robot vision.","active vision; humanoid robots; object tracking and segmentation; vergence eye movements; convergence; smooth pursuit eye movements; stereopsis; optimal feature selection; saccadic eye movements","en","doctoral thesis","","","","","","","","","Mechanical, Maritime and Materials Engineering","BioMechanical Engineering","","","",""
"uuid:7d5ff38c-1761-417e-bc02-b122338ce75b","http://resolver.tudelft.nl/uuid:7d5ff38c-1761-417e-bc02-b122338ce75b","Predicting long-term and short-term tidal flat morphodynamics using a dynamic equilibrium theory","Hu, Z.; Wang, Z.B.; Zitman, T.J.; Stive, M.J.F.; Bouma, T.J.","","2015","Dynamic equilibrium theory is a fruitful concept, which we use to systematically explain the tidal flat morphodynamic response to tidal currents, wind waves, sediment supply, and other sedimentological drivers. This theory stems from a simple analytical model that derives the tide- or wave-dominated tidal flat morphology by assuming that morphological equilibrium is associated with uniform bed shear stress distribution. Many studies based on observation and process-based modeling tend to agree with this analytical model. However, a uniform bed shear stress rarely exists on actual or modeled tidal flats, and the analytical model cannot handle the spatially and temporally varying bed shear stress. In the present study, we develop a model based on the dynamic equilibrium theory and its core assumption. Different from the static analytical model, our model explicitly accounts for the spatiotemporal bed shear stress variations for tidal flat dynamic prediction. To test our model and the embedded theory, we apply the model for both long-term and short-term morphological predictions. The long-term modeling is evaluated qualitatively against previous process-based modeling. The short-term modeling is evaluated quantitatively against high-resolution bed-level monitoring data obtained from a tidal flat in Netherlands. The model results show good performances in both qualitative and quantitative tests, indicating the validity of the dynamic equilibrium theory. Thus, this model provides a valuable tool to enhance our understanding of the tidal flat morphodynamics and to apply the dynamic equilibrium theory for realistic morphological predictions.","","en","journal article","American Geophysical Union (AGU)","","","","","","","2016-03-18","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:f6b11789-2f99-4a9f-969e-d738df001943","http://resolver.tudelft.nl/uuid:f6b11789-2f99-4a9f-969e-d738df001943","Shear banding in entangled polymers in the micron scale gap: A confocal-rheoscopic study","Boukany, P.E.; Wang, S.Q.; Ravindranath, S.; James Lee, L.J.","","2015","Recent shear experiments in well-entangled polymer solutions demonstrated that interfacial wall slip is the only source of shear rate loss and there is no evidence of shear banding in the micron scale gap. In this work, we experimentally elucidate how molecular parameters such as slip length, b, influence shear inhomogeneity of entangled polybutadiene (PBD) solutions during shear in a small gap H ? 50 ?m. Simultaneous rheometric and velocimetric measurements are performed on two PBD solutions with the same level of entanglements (Z = 54) in two PBD solvents with molecular weights of 1.5 kg mol?1 and 10 kg mol?1 that possess different levels of shear inhomogeneity (2bmax/H = 17 and 240). For the PBD solution made with a low molecular weight PBD solvent of 1.5 kg mol?1, wall slip is the dominant response within the accessible range of the shear rate, i.e., up to the nominal Weissenberg number (Wi) as high as 290. On the other hand, wall slip is minimized using a high molecular-weight PBD solvent of 10 kg mol?1 so that bulk shear banding is observed to take place in the steady state for Wi > 100. Finally, these findings and previous results are in good agreement with our recently proposed phase diagram in the parameter space of apparent Wi versus 2bmax/H suggesting that shear banding develops across the micron scale gap when the imposed Wi exceeds 2bmax/H [Wang et al., Macromolecules, 2011, 44, 183].","Gold for Gold; Open Access","en","journal article","RSC Publishing","","","","","","","","Applied Sciences","Chemical Engineering","","","",""
"uuid:598f295a-f9ee-435c-b2ad-4095617e86cf","http://resolver.tudelft.nl/uuid:598f295a-f9ee-435c-b2ad-4095617e86cf","Investigation of Lagrangian coherent structures in a wake-induced boundary layer transition","He, G.; Pang, C.; Gao, Q.; Feng, L.; Wang, J.","He, G. (author); Pang, C. (author); Gao, Q. (author); Feng, L. (author); Wang, J. (author)","2015","The evolution of coherent structures in a flat plate boundary layer transition induced by the cylinder wake is investigated using the particle image velocimetry (PIV) technique. The finite-time Lyapunov exponent (FTLE), which characterizes the amount of stretching about the flow trajectory, is used to extract the Lagrangian coherent structures. It is revealed that secondary vortex is induced by the cylinder wake vortices in the near wall region,which would evolve into hairpin vortex as it convects downstream. The subsequent evolvement of the hairpin vortex, characterized by the regeneration of offspring hairpin vortex upstream of it, leads to the appearance of the hairpin packet and the boundary layer finally reaches a turbulent state.","","en","conference paper","","","","","","","","","","","","","",""
"uuid:22b8fe39-2d38-4766-8d71-93704f85e83a","http://resolver.tudelft.nl/uuid:22b8fe39-2d38-4766-8d71-93704f85e83a","Turbulent structures in unsteady wall-bounded flow subject to temporal acceleration","Wang, Z.; Talha, T.; Chung, Y.","Wang, Z. (author); Talha, T. (author); Chung, Y. (author)","2015","Direct numerical simulations (DNS) of a transient turbulent channel flow subject to constant temporal acceleration have been performed with a final Reynolds number of $\Retau=800$. The response of turbulent structures to the temporal acceleration is investigated. A significant delay in the response of turbulent flow is observed in various turbulent properties. It is found that the response of turbulent flow to temporal acceleration consists of two stages: the destruction of the initial \emph{old} turbulence, followed by the generation of \emph{new} turbulence associated with a higher $Re$ number. The \emph{new} turbulence is much stronger than the \emph{old} turbulence.","","en","conference paper","","","","","","","","","","","","","",""
"uuid:6b18d198-9227-4143-a131-aac6a3d452de","http://resolver.tudelft.nl/uuid:6b18d198-9227-4143-a131-aac6a3d452de","Scaling analysis based on extremal point topology","Wang, L.; Huang, Y.","Wang, L. (author); Huang, Y. (author)","2015","The interaction of different scales is among the most interesting and challenging features in turbulence research. Existing approaches used for scaling analysis such as structure-function and Fourier spectrum method have their respective limitations, for instance scale mixing, i.e. the so-called infrared and ultraviolet effects. To make improvement in this regard, a new method, multi-level segment analysis (MSA) based on the local extrema statistics, has been developed. Data test results show that MSA can successfully reveal different scaling regimes in complex systems such as Lagrangian and two-dimensional turbulence, which have been remaining controversial in turbulence research. In principle MSA can generally be applied for various analyses.","","en","conference paper","","","","","","","","","","","","","",""
"uuid:c68d6ca2-6c8f-4337-a590-fd4df41efc7c","http://resolver.tudelft.nl/uuid:c68d6ca2-6c8f-4337-a590-fd4df41efc7c","Improvement of train-track interaction in transition zones via reduction of ballast damage","Wang, H.; Markine, V.L.; Dollevoet, R.P.B.J.; Shevtsov, I.Y.","","2015","Transition zones in railway tracks are locations with considerable changes in the vertical stiffness of the rail support. Typically they are located near engineering structures, such as bridges, culverts, tunnels and level crossings. In such locations, the differential settlement always exists and continually grows without proper maintenance. Due to the effect of the differential settlement and bending stiffness of the rails, hanging sleepers may exist, which are invisible under ordinary circumstances, but generate high displacements and impact during train passages. Therefore, a method to detect the differential settlement (Or hanging sleepers) of track transition zones is presented, which is combined with numerical simulations and field measurements. The numerical model of the track transition zone developed here uses contact elements for modelling the connection between the sleepers and the ballast, bilinear springs for fastening system and Hertzian spring for wheel-rail interaction. The model is capable for simulating the dynamic behaviour of the transition zones with differential settlement or hanging sleepers. Using the model, the dynamic responses such as the vertical displacement of rail, the dynamic wheel load, the axial stress in rail and the vertical stress of ballast has been be obtained and analysed. The field measurements were performed as well. Using Video Gauge System (VGS) the vertical displacements of rail in the vicinity of a track transition zone were measured. The differential settlement of the measured transition zone was analysed by comparing the measurement and numerical results. Finally, based on the obtained findings and the simulation results some track design improvements and suggestions for maintenance actions are given.","","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Structural Engineering","","","",""
"uuid:16511dd6-dbb6-4c1e-b502-f770d860aa09","http://resolver.tudelft.nl/uuid:16511dd6-dbb6-4c1e-b502-f770d860aa09","Monotone multiscale finite volume method","Wang, Y.; Hajibeygi, H.; Tchelepi, H.A.","","2015","The MultiScale Finite Volume (MSFV) method is known to produce non-monotone solutions. The causes of the non-monotone solutions are identified and connected to the local flux across the boundaries of primal coarse cells induced by the basis functions. We propose a monotone MSFV (m-MSFV) method based on a local stencil-fix that guarantees monotonicity of the coarse-scale operator, and thus, the resulting approximate fine-scale solution. Detection of non-physical transmissibility coefficients that lead to non-monotone solutions is achieved using local information only and is performed algebraically. For these ‘critical’ primal coarse-grid interfaces, a monotone local flux approximation, specifically, a Two-Point Flux Approximation (TPFA), is employed. Alternatively, a local linear boundary condition can be used for the dual basis functions to reduce the degree of non-monotonicity. The local nature of the two strategies allows for ensuring monotonicity in local sub-regions, where the non-physical transmissibility occurs. For practical applications, an adaptive approach based on normalized positive off-diagonal coarse-scale transmissibility coefficients is developed. Based on the histogram of these normalized coefficients, one can remove the large peaks by applying the proposed modifications only for a small fraction of the primal coarse grids. Though the m-MSFV approach can guarantee monotonicity of the solutions to any desired level, numerical results illustrate that employing the m-MSFV modifications only for a small fraction of the domain can significantly reduce the non-monotonicity of the conservative MSFV solutions.","multiscale finite volume method; iterative multiscale methods; algebraic multiscale solver; scalable linear solvers; monotone flux approximation schemes; multipoint flux approximation; porous media","en","journal article","Springer","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""
"uuid:d940cff1-457e-4c2c-afba-962c7d4400ec","http://resolver.tudelft.nl/uuid:d940cff1-457e-4c2c-afba-962c7d4400ec","Quantifying the robustness of metro networks","Wang, X.; Koç, Y.; Derrible, S.; Nasir Ahmad, Sk.; Kooij, R.E.","","2015","Metros (heavy rail transit systems) are integral parts of urban transportation systems. Failures in their operations can have serious impacts on urban mobility, and measuring their robustness is therefore critical. Moreover, as physical networks, metros can be viewed as network topological entities, and as such they possess measurable network properties. In this paper, by using network science and graph theoretical concepts, we investigate both theoretical and experimental robustness metrics (i.e., the robustness indicator, the effective graph conductance, and the critical thresholds) and their performance in quantifying the robustness of metro networks under random failures or targeted attacks. We find that the theoretical metrics quantify different aspects of the robustness of metro networks. In particular, the robustness indicator captures the number of alternative paths and the effective graph conductance focuses on the length of each path. Moreover, the high positive correlation between the theoretical metrics and experimental metrics and the negative correlation within the theoretical metrics provide significant insights for planners to design more robust system while accommodating for transit specificities (e.g., alternative paths, fast transferring).","","en","conference paper","Kyoto University - Japan Society of Transportation Engineering","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Network Architectures and Services","","","",""
"uuid:42caf5fd-d00f-4f1d-bfc1-15b172b875c6","http://resolver.tudelft.nl/uuid:42caf5fd-d00f-4f1d-bfc1-15b172b875c6","Windows of opportunity for salt marsh vegetation establishment on bare tidal flats: The importance of temporal and spatial variability in hydrodynamic forcing","Hu, Z.; Van Belzen, J.; Van der Wal, D.; Balke, T.; Wang, Z.B.; Stive, M.J.F.; Bouma, T.J.","","2015","Understanding the mechanisms limiting and facilitating salt marsh vegetation initial establishment is of widespread importance due to the many valuable services salt marsh ecosystems offer. Salt marsh dynamics have been investigated by many previous studies, but the mechanisms that enable or disable salt marsh initial establishment are still understudied. Recently, the “windows of opportunity” (WoO) concept has been proposed as a framework providing an explanation for the initial establishment of biogeomorphic ecosystems and the role of physical disturbance herein. A WoO is a sufficiently long disturbance-free period following seedling dispersal, which enables successful establishment. By quantifying the occurrence of WoO, vegetation establishment pattern can be predicted. For simplicity sake and as prove of concept, the original WoO framework considers tidal inundation as the only physical disturbance to salt marsh establishment, whereas the known disturbance from tidal currents and wind waves is ignored. In this study, we incorporate hydrodynamic forcing in the WoO framework. Its spatial and temporal variability is considered explicitly in a salt marsh establishment model. We used this model to explain the observed episodic salt marsh recruitment in the Westerschelde Estuary, Netherlands. Our results reveal that this model can significantly increase the spatial prediction accuracy of salt marsh establishment compared to a model that excludes the hydrodynamic disturbance. Using the better performing model, we further illustrate how tidal flat morphology determines salt marsh establishing elevation and width via hydrodynamic force distribution. Our model thus offers a valuable tool to understand and predict bottlenecks of salt marsh restoration and consequences of changing environmental conditions due to climate change.","","en","journal article","American Geophysical Union","","","","","","","2016-01-31","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:f0483aa3-2a1b-4700-b78e-12dbab6c6a2b","http://resolver.tudelft.nl/uuid:f0483aa3-2a1b-4700-b78e-12dbab6c6a2b","Buckling optimization of steering stiffeners for grid-stiffened composite structures","Wang, D.; Abdalla, M.M.","","2015","Grid-stiffened composite structures, where the skin is stiffened by a lattice of stiffeners, not only allow for significant reduction in structural weight but are also competitive in terms of structural stability and damage tolerance compared with sandwich composite structures. As the development of Automated Fiber Placement (AFP) technology matures, integrated construction of skin and stiffeners is easily manufacturable. Optimization of grid-stiffened structures is needed to fully take advantage of the expanded design possibilities. In this paper, a steering/curved stiffener layout is optimized for grid-stiffened composite structures in order to enhance the structural buckling resistance. A homogenization method is used to calculate the equivalent material properties. Global and local buckling loads are determined by a global/local coupled strategy. A linear variation of stiffener angles is assumed resulting in the formation of a locally rhombic lattice pattern by the stiffeners. Moreover, manufacturing constraints are considered in the optimization by setting a lower bound on the stiffener spacing. Since the calculation is implemented on an equivalent model with a fixed mesh, it is possible to use a gradient-based optimization algorithm. A comparison between the performance of grid-stiffened composite structures with curved stiffeners, with straight stiffeners, and with variable-stiffness skins with curved fibers, reveals the potential of curved stiffener configurations in improving structural efficiency.","curved stiffeners; optimization; grid-stiffened composite structures; global and local buckling","en","conference paper","ICCM","","","","","","","","Aerospace Engineering","Aerospace Structures & Materials","","","",""
"uuid:bf539027-147f-485b-a47e-78f71050380b","http://resolver.tudelft.nl/uuid:bf539027-147f-485b-a47e-78f71050380b","Characterization of Failure and Permanent Deformation Behaviour of Asphalt Concrete","Wang, J.G.","Molenaar, A.A.A. (promotor); Wu, S.P. (promotor)","2015","Asphalt concrete is a viscoelastic material consisting of aggregates, filler and bitumen. The response of asphalt concrete is highly dependent on temperature, loading rate and confining pressure. Permanent deformation is one of the most important distresses developing during the flexible pavement service life. The total deformation which is visible at the pavement surface is the sum of the deformation that developed in each and every layer. In this thesis however attention will only be paid to permanent deformation of the asphalt layers. The main goal of this research was to investigate and better understand the permanent deformation behaviour of asphalt mixtures at 50°C which is a temperature that regularly occurs in asphalt wearing courses in the Netherlands and which therefore is applied in the Dutch standard for testing the resistance to permanent deformation of wearing courses. The thesis is divided in two parts. The first part focuses on sample preparation, testing procedures and fundamental properties of dense asphalt concrete (DAC) and porous asphalt concrete (PAC) mixtures and skeletons. In the second part the focus is on the prediction of permanent deformation. In the first part of this research special attention was paid to the following aspects: Effects of end constraints on test results Friction between the ends of the specimen and the top and bottom loading platens introduces extra confinement at the top and bottom of the specimen. In this research an extensive monotonic compressive testing program was performed on DAC and PAC mixtures under two different end contact conditions being full friction and reduced friction. “Full friction” was achieved by gluing the specimen to the top and bottom loading platens. “Reduced friction” was obtained by using a sandwich-shaped friction reduction system which consisted of two thin rubber sheets and vacuum grease in between. The results show that in the case of “full friction” the failure stress is overestimated and the displacement at failure is underestimated. The results also show that in the case of uniaxial testing without confinement and when using the friction reduction system, a deformation correction is needed to obtain the true deformation of the specimen. When confining pressure is applied deformations due to the friction reduction system can be ignored. The stress-strain behaviour of asphalt mixtures The permanent deformation behaviour of asphalt mixtures is highly dependent on temperature, stress conditions and number of load repetitions. A better understanding of the stress-strain behaviour of asphalt mixtures is beneficial for a better understanding of the permanent deformation. Therefore an extensive monotonic compressive test program was conducted on DAC and PAC at 40°C and 50°C with 3 various confining pressures and 5 different loading rates. The test results showed that the stress-strain behaviour of DAC significantly depends on temperature, strain rate and confinement. The results also showed that at high temperatures the PAC mixture behaves much alike a granular material with little cohesion. In this case the skeleton of PAC plays a significant role in the mechanical behaviour and this behaviour is highly dependent on the level of confinement. Behaviour of aggregate skeletons Permanent deformation develops at elevated temperatures. At elevated temperatures, the contribution of the aggregate skeleton becomes crucial. For this reason monotonic compressive tests were conducted on DAC and PAC skeletons at two strain rates and two confining pressure levels. The stress-strain behaviour of the DAC and PAC skeleton were compared with the stress-strain behaviour of both mixtures. The results implied that the bituminous mastic in DAC acts as a binder and contributes to the behaviour of the DAC asphalt mixture. The results also showed that the PAC aggregate skeleton shows typical elastoplastic behaviour regardless of the strain rates. In the second part of this thesis repeated load triaxial tests to study the development of permanent deformation were performed on the DAC mixture at 50°C and the following questions related to permanent deformation of the DAC mixture were discussed. Scatter observed in permanent deformation results A power function was used to model the obtained permanent deformation. A large scatter in the model parameters was observed even at the same stress ratio for selected test specimens. The possible relation between the scatter on one hand and the air voids content and resilient modulus of specimens on the other was studied. CT scanning was used to investigate the internal structure of the intact and tested specimens. The results showed that there is no clear relationship between air voids and the parameters describing the development of the permanent deformation with increasing number of load repetitions. The results also showed that the model parameters were stress dependent and a strong relationship was found between the model parameters and the resilient modulus after 1000 load repetitions. The CT scan results showed that different failure modes took place in the permanent deformation tests and that the internal structure of specimens is important for the development of permanent deformation. It is believed that part of the scatter in the test results can be explained by the variation in internal structure. Influence of loading pattern on permanent deformation The influence of different loading pulses and rest times on the permanent deformation of DAC was also investigated by performing Triaxial Repeated Load Permanent Deformation (TRLPD) test. The tests were performed at two different loading patterns, being 0.2 s load + 1.8 s rest and 0.4 s load + 0.6 s rest, and at two confinement levels of 150 kPa with a stress ratio 0.43 and 100 kPa with a stress ratio 0.3. The results showed that the stress ratio has a significant influence on the permanent deformation while the loading time has little influence on the development of permanent deformation. At the same stress level it seems that the longer loading time does not result in larger permanent deformation. Evolution of the resilient modulus in relation to the number of load repetitions In order to obtain a better understanding of the relationship between permanent strain and resilient strain which is developed in the DAC test specimens during the repeated load triaxial tests, the evolution of the resilient modulus of DAC with the number of load repetitions was investigated and modelled. The results showed that the resilient modulus of DAC reduced during the first load repetitions and tended to take a constant value after 1000 load repetitions. Evolution of Burgers’ model parameters in relation to the number of load repetitions The measured total strain was decomposed into elastic strain, delayed elastic strain and viscous permanent strain and modelled by means of the Burgers’ model. The evolution of Burgers’ model parameters obtained at two different loading patterns was investigated in this study. It was found that the value of the parameter representing the dashpot in series, used for modelling the permanent deformation, increased with increasing number of load repetitions and tended to be constant after thousands of load repetitions. This value however strongly decreased when dilation of the specimen occurred. The loading pattern had a significant influence on the value of this viscous parameter Shake down limit in permanent deformation of DAC In order to explore the existence of a shakedown limit for the tested DAC mixture, five representative permanent deformation tests were analyzed. From this analysis it appeared that below a stress ratio of 0.3 (the ratio of applied vertical stress to vertical stress at failure at the same confinement level) only a limited amount of permanent deformation developed after a large number of load repetitions. The stress ratio of 0.3 is proposed to be the shake down limit at 50°C for the test conditions and DAC mixture used in this research. Permanent deformation modeling based on Dissipated Energy Concept Most of the permanent deformation prediction models are simply relating permanent deformation to stress conditions and the number of load repetitions. In this study a permanent deformation model was developed based on dissipated energy. It was shown that the initial dissipate energy, the applied stress level and the number of load repetitions explain very well the permanent deformation development.","Failure; Permanent Deformation; Dense Asphalt Concrete; Porous Asphalt Concrete; X-Ray Computer Tomography (CT) Scan; Dissipated Energy; Friction Reduction System; Stress strain in Asphalt Concrete; Burgers' Model","en","doctoral thesis","","","","","","","","","Civil Engineering and Geosciences","Structure Engineering","","","",""
"uuid:fbc19924-21b0-42f6-998f-3bc339d51a71","http://resolver.tudelft.nl/uuid:fbc19924-21b0-42f6-998f-3bc339d51a71","De novo sequencing of two novel peptides homologous to calcitonin-like peptides, from skin secretion of the Chinese Frog, Odorrana schmackeri","Evaristo, G.P.C.; Pinkse, M.W.H.; Chen, T.; Wang, L.; Mohammed, S.; Heck, A.J.R.; Mathes, I.; Lottspeich, F.; Shaw, C.; Albar, J.P.; Verhaert, P.D.E.M.","","2015","An MS/MS based analytical strategy was followed to solve the complete sequence of two new peptides from frog (Odorrana schmackeri) skin secretion. This involved reduction and alkylation with two different alkylating agents followed by high resolution tandem mass spectrometry. De novo sequencing was achieved by complementary CID and ETD fragmentations of full-length peptides and of selected tryptic fragments. Heavy and light isotope dimethyl labeling assisted with annotation of sequence ion series. The identified primary structures are GCD[I/L]STCATHN[I/L]VNE[I/L]NKFDKSKPSSGGVGPESP-NH2 and SCNLSTCATHNLVNELNKFDKSKPSSGGVGPESF-NH2, i.e. two carboxyamidated 34 residue peptides with an aminoterminal intramolecular ring structure formed by a disulfide bridge between Cys2 and Cys7. Edman degradation analysis of the second peptide positively confirmed the exact sequence, resolving I/L discriminations. Both peptide sequences are novel and share homology with calcitonin, calcitonin gene related peptide (CGRP) and adrenomedullin from other vertebrates. Detailed sequence analysis as well as the 34 residue length of both O. schmackeri peptides, suggest they do not fully qualify as either calcitonins (32 residues) or CGRPs (37 amino acids) and may justify their classification in a novel peptide family within the calcitonin gene related peptide superfamily. Smooth muscle contractility assays with synthetic replicas of the S–S linked peptides on rat tail artery, uterus, bladder and ileum did not reveal myotropic activity.","calcitonin-like peptides; CGRP-like peptides; adrenomedullin-like peptides; frog skin; LC MSn; de novo sequencing","en","journal article","Elsevier","","","","","","","","Applied Sciences","BT/Biotechnology","","","",""
"uuid:17f6f417-7a67-4301-80c7-628feb4220ff","http://resolver.tudelft.nl/uuid:17f6f417-7a67-4301-80c7-628feb4220ff","Train Trajectory Optimization with Signalling Constraints (PPT)","Wang, P. (TU Delft Transport and Planning); Goverde, R.M.P. (TU Delft Transport and Planning)","","2015","","","en","other","","","","","","","","","","","Transport and Planning","","",""
"uuid:2c4d651a-c63d-4345-9467-4a63e9149680","http://resolver.tudelft.nl/uuid:2c4d651a-c63d-4345-9467-4a63e9149680","Integrity monitoring-based ratio test for GNSS integer ambiguity validation","Li, L.; Li, Z.; Yuan, H.; Wang, L.; Yanqing, H.","","2015","The combination of multiple global navigation satellite systems (GNSSs) is able to improve the accuracy and reliability, which is beneficial for navigation in safety–critical applications. Due to the relatively low accuracy of pseudorange observations, the single-epoch GNSS real-time kinematic (RTK) using phase observations can be utilized to achieve centimeter accuracy positioning instantaneously. Since the traditional ratio tests for ambiguity validation are not reliable in the presence of biases, it is therefore difficult for the single-epoch RTK to achieve high precision and high reliability, simultaneously. Instead of using an empirical constant detection threshold or a fixed failure/success rate requirement in the ratio tests for ambiguity validation, we propose an integrity monitoring-based ratio test (IM-RT). It uses the ambiguity protection level to control the false alarm and missed detection errors. The performance of the proposed method is tested by using simulated and real-world data. The simulation results show that the IM-RT can obtain an optimal balance between the false alarm and missed detection performance. The experiments from kinematic real-world data indicate that the IM-RT improves the positioning accuracy by over 10 cm and enhances the continuity by 11 %, when compared with the fixed detection threshold-based ratio test.","ambiguity validation; integrity monitoring; ratio test; real-time kinematic; GNSS","en","journal article","Springer","","","","","","","","Civil Engineering and Geosciences","Geoscience & Remote Sensing","","","",""
"uuid:2ef62c2a-a587-4a02-b7f0-9df62e9b0886","http://resolver.tudelft.nl/uuid:2ef62c2a-a587-4a02-b7f0-9df62e9b0886","Path planning for first responders in the presence of moving obstacles","Wang, Z.","Van Oosterom, P.J.M. (promotor)","2015","Navigation services have gained much importance for all kinds of human activities ranging from tourist navigation to support of rescue teams in disaster management. However, despite the considerable amount of route guidance research that has been performed, many issues that are related to navigation for first responders still need to be addressed. During disasters, emergencies can result in different types of moving obstacles (e.g., fires, plumes, floods), which make some parts of the road network temporarily unavailable. After such incidents occur, responders have to go to different destinations to perform their tasks in the environment affected by the disaster. Therefore they need a path planner that is capable of dealing with such moving obstacles, as well as generating and coordinating their routes quickly and efficiently. During the past decades, more and more hazard simulations, which can modify the models with incorporation of dynamic data from the field, have been developed. These hazard simulations use methods such as data assimilation, stochastic estimation, and adaptive measurement techniques, and are able to generate more reliable results of hazards. This would allow the hazard simulation models to provide valuable information regarding the state of road networks affected by hazards, which supports path planning for first responders among the moving obstacles. The objective of this research is to develop an integrated navigation system for first responders in the presence of moving obstacles. Such system should be able to navigate one or more responders to one or multiple destinations avoiding the moving obstacles, using the predicted information of the moving obstacles generated from by hazard simulations. In this dissertation, the objective we have is expressed as the following research question: ""How do we safely and efficiently navigate one or more first responders to one or more destinations avoiding moving obstacles?"" To address the above research questions, this research has been conducted using the following outline: 1). literature review; 2). conceptual design and analysis; 3). implementation of the prototype; and 4). assessment of the prototype and adaption. We investigated previous research related to navigation in disasters, and designed an integrated navigation system architecture, assisting responders in spatial data storage, processing and analysis. Within this architecture, we employ hazard models to provide the predicted information about the obstacles, and select a geo-database to store the data needed for emergency navigation. Throughout the development of the prototype navigation system, we have proposed: 1). a multi-agent system, which supports the spatial data processing and analysis involved in the routing process; 2). algorithms for path planning in the presence of moving obstacles; 3). spatial data models, which structure the disaster-related information for routing. We have implemented a prototype of multi-agent based navigation system, and applied it to different navigation cases. The experimental results demonstrate the capability of our system in providing safe routes for responders, and show the potential for a wider range of applications.","Path planning; Taxonomy; Multi-agent system; Spatial data model; Algorithms; Moving obstacles","en","doctoral thesis","","","","","","","","","Architecture and The Built Environment","OTB","","","",""
"uuid:d2798239-a5cc-482a-bb1e-7b1b87ab5697","http://resolver.tudelft.nl/uuid:d2798239-a5cc-482a-bb1e-7b1b87ab5697","A novel capsule-based selfrecovery system with a chloride ion trigger","Xiong, W.; Tang, J.; Zhu, G.; Han, N.; Schlangen, E.; Dong, B.; Wang, X.; Xing, F.","","2015","Steel is prone to corrosion induced by chloride ions, which is a serious threat to reinforced concrete structures, especially in marine environments. In this work, we report a novel capsule-based selfrecovery system that utilizes chloride ions as a trigger. These capsules, which are functionalized via a smart response to chloride ions, are fabricated using a silver alginate hydrogel that disintegrates upon contact with chloride ions, and thereby releases the activated core materials. The experimental results show that the smart capsules respond to a very low concentration of chloride ions (0.1 wt%). Therefore, we believe that this novel capsule-based self-recovery system will exhibit a promising prospect for self-healing or corrosion inhibition applications.","civil engineering; characterization and analytical techniques","en","journal article","Nature Publishing Group","","","","","","","","Civil Engineering and Geosciences","Structural Engineering","","","",""
"uuid:ff3dd813-59c4-40b4-90ef-dc1b320f433a","http://resolver.tudelft.nl/uuid:ff3dd813-59c4-40b4-90ef-dc1b320f433a","Impact of spatial and temporal resolution of rainfall inputs on urban hydrodynamic modelling outputs: A multi-catchment investigation","Ochoa-Rodriguez, S.; Wang, L.P.; Gires, A.; Pina, R.D.; Reinoso-Rondinel, R.; Bruni, G.; Ichiba, A.; Gaitan, S.; Cristiano, E.; Van Assel, J.; Kroll, S.; Murla-Tuyls, D.; Tisserand, B.; Schertzer, D.; Tchiguirinskaia, I.; Onof, C.; Willems, P.; Ten Veldhuis, M.C.","","2015","Urban catchments are typically characterised by high spatial variability and fast runoff processes resulting in short response times. Hydrological analysis of such catchments requires high resolution precipitation and catchment information to properly represent catchment response. This study investigated the impact of rainfall input resolution on the outputs of detailed hydrodynamic models of seven urban catchments in North-West Europe. The aim was to identify critical rainfall resolutions for urban catchments to properly characterise catchment response. Nine storm events measured by a dual-polarimetric X-band weather radar, located in the Cabauw Experimental Site for Atmospheric Research (CESAR) of the Netherlands, were selected for analysis. Based on the original radar estimates, at 100 m and 1 min resolutions, 15 different combinations of coarser spatial and temporal resolutions, up to 3000 m and 10 min, were generated. These estimates were then applied to the operational semi-distributed hydrodynamic models of the urban catchments, all of which have similar size (between 3 and 8 km2), but different morphological, hydrological and hydraulic characteristics. When doing so, methodologies for standardising model outputs and making results comparable were implemented. Results were analysed in the light of storm and catchment characteristics. Three main features were observed in the results: (1) the impact of rainfall input resolution decreases rapidly as catchment drainage area increases; (2) in general, variations in temporal resolution of rainfall inputs affect hydrodynamic modelling results more strongly than variations in spatial resolution; (3) there is a strong interaction between the spatial and temporal resolution of rainfall input estimates. Based upon these results, methods to quantify the impact of rainfall input resolution as a function of catchment size and spatial–temporal characteristics of storms are proposed and discussed.","urban hydrology; spatialtemporal resolution; radar rainfall; X-band radar; urban drainage; hydrodynamic models","en","journal article","Elsevier","","","","","","","","Civil Engineering and Geosciences","Geoscience & Remote Sensing","","","",""
"uuid:83ae752a-4de3-4b0b-aae5-bf691dece2b6","http://resolver.tudelft.nl/uuid:83ae752a-4de3-4b0b-aae5-bf691dece2b6","River-tide dynamics: Exploration of nonstationary and nonlinear tidal behavior in the Yangtze River estuary","Guo, L.; Van der Wegen, M.; Jay, D.A.; Matte, P.; Wang, Z.B.; Roelvink, J.A.; He, Q.","","2015","River-tide dynamics remain poorly understood, in part because conventional harmonic analysis (HA) does not cope effectively with nonstationary signals. To explore nonstationary behavior of river tides and the modulation effects of river discharge, this work analyzes tidal signals in the Yangtze River estuary using both HA in a nonstationary mode and continuous wavelet transforms (CWT). The Yangtze is an excellent natural laboratory to analyze river tides because of its high and variable flow, its length, and the fact that there are do dams or reflecting barriers within the tidal part of the system. Analysis of tidal frequencies by CWT and analysis of subtidal water level and tidal ranges reveal a broad range of subtidal variations over fortnightly, monthly, semiannual, and annual frequencies driven by subtidal variations in friction and by variable river discharges. We employ HA in a nonstationary mode (NSHA) by segregating data within defined flow ranges into separate analyses. NSHA quantifies the decay of the principal tides and the modulation of M4 tide with increasing river discharges. M4 amplitudes decrease far upriver (landward portion of the estuary) and conversely increase close to the ocean as river discharge increases. The fortnightly frequencies reach an amplitude maximum upriver of that for over tide frequencies, due to the longer wavelength of the fortnightly constituents. These methods and findings should be applicable to large tidal rivers globally and have broad implications regarding management of navigation channels and ecosystems in tidal rivers.","","en","journal article","American Geophysical Union","","","","","","","2015-11-19","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:5ceba8c6-2222-4081-8758-76bbd0740f70","http://resolver.tudelft.nl/uuid:5ceba8c6-2222-4081-8758-76bbd0740f70","Hydrologic and cryospheric processes observed from space","Menenti, M.; Li, X.; Wang, J.; Vereecken, H.; Li, J.; Mancini, M.; Liu, Q.; Jia, L.; Li, J.; Kuenzer, C.; Huang, S.; Yesou, H.; Wen, J.; Kerr, Y.; Cheng, X.; Gourmelen, N.; Ke, C.; Ludwig, R.; Lin, H.; Eineder, M.; Ma, Y.; Su, Z.B.","","2015","Ten Dragon 3 projects deal with hydrologic and cryosphere processes, with a focus on the Himalayas and Qinghai – Tibet Plateau, but not limited to that. At the 1st Dragon 3 Progress Symposium in 2013 a significant potential for a better and deeper integration appeared very clearly and we worked out an overview of the ten projects identifying specific issues and objectives shared by at least two projects. At the Mid Term Symposium in 2014 a joint session was held over two days. As regards cryospheric processes science highlights covered: Glacier flow velocity by optical and SAR features tracking and InSAR; Patterns in space and time of glacier flow velocity; Mass change estimated with DTM-s and altimetry; Reflectance and LST used to classify glacier surface and understand surface processes, Inventory and changes in the number and area of lakes in the Qinghai – Tibet Plateau 1970, 1990, 2000 and 2010; Deformation of permafrost along the Qinghai – Tibet railway. Highlights on hydrologic processes included: Global comparison of SMOS, ASCAT and ERA soil moisture data products; Relative deviations evaluated by climate zone; Soil moisture data products improved with ancillary data; Assimilation of FY - , TRMM and GPM precipitation data products in WRF; Improved algorithm and data products on fractional snow cover; Improvement of MODIS ET with assimilation of LST; TRMM data products evaluated in the Yangtze; Calibration of river basin models using LST; System to calibrate, correct and normalize (spatial, spectral) data collected by imaging spectral radiometers; Integration of data acquired by different sensors, e.g. ET Monitor with optical and microwave (SMOS, FY – 3) data; Hydrological data products used both for forcing and evaluation of Qinghai – Tibet Plateau hydrological model; Wetlands vulnerability assessed through changes in land cover 1987 – 2013; Multi incidence angle and multi – temporal SAR to monitor water extent. In the general session a proposal for a Dragon Water Cycle Initiative was presented.","terrestrial water cycle; multi sensor data products; glaciers; water resources; high elevation climate","en","conference paper","ISPRS","","","","","","","","Civil Engineering and Geosciences","Geoscience & Remote Sensing","","","",""
"uuid:6a9e06e1-d7ba-411b-b8f9-7f373fcb9c50","http://resolver.tudelft.nl/uuid:6a9e06e1-d7ba-411b-b8f9-7f373fcb9c50","Thermal management of High-Current Bidirectional Isolated DC-DC Converters","Wang, Y.","Ferreira, J.A. (promotor)","2015","","high current; DAB; thermal management; transformer design; loss modeling","en","doctoral thesis","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Electrical Sustainable Energy","","","",""
"uuid:91e2668d-83e1-4ace-b110-3dc2109238e5","http://resolver.tudelft.nl/uuid:91e2668d-83e1-4ace-b110-3dc2109238e5","Climate Change Impacts on River Floods: Uncertainty and Adaptation","Wang, L.","Vrijling, J.K. (promotor); Van Gelder, P.H.A.J.M. (promotor)","2015","The modelling frameworks, which include greenhouse gas emission scenarios, climate models, downscaling methods and hydrological models, are generally used to assess climate change impacts on river floods. In this research, the uncertainty associated with each component of the modelling framework is analysed with particular reference to climate change impacts on flood frequency. A method of risk-averse economic optimisation has been proposed for adapting river dikes to climate change under uncertainty. The Huai River Basin in China has been selected as a case study. The outputs of climate models, i.e., General Circulation Models (GCMs), under greenhouse gas emission scenarios have been commonly used as fundamental inputs of the climate change impact assessments. The analysis in this thesis employed the climate model projections of the WCRP CMIP3 and CMIP5 datasets. In Chapter 2, a brief introduction of emission scenarios, as well as a preliminary analysis of the simulative ability and future projections of the participating climate models, is provided. The results confirm the necessity to bias-correct and downscale the climate model outputs before being used in impact-related studies. The annual mean temperature in the study area is suggested to increase up to 8oC at the end of this century under a high greenhouse gas emission scenario without mitigation measures. The standard deviation of precipitation intensity is suggested to increase, especially in summer, which may in the future lead to high-magnitude floods. Empirical statistical downscaling methods are becoming increasingly popular in climate change impact assessments that require downscaling multi-GCM projections. In Chapter 3 empirical statistical downscaling methods are classified based on calibration strategies and statistical transformations. Ten combinations of calibration strategies and transformation methods were used to represent a range of empirical statistical downscaling methods. To test the performance of these methods in downscaling daily precipitation and temperature, an inter-model cross validation was carried out using an ensemble of 16 GCMs. These downscaling methods were further applied to downscale the climate for the future period to assess the associated uncertainties. The results show that the change factor based methods outperform the bias correction based methods in projecting the probability distribution of downscaled daily temperature. With the change factor calibration strategy, simply adding (for temperature) or multiplying (for precipitation) the mean change factor is sufficient to represent most of the relative changes projected by GCMs. The use of quantile based methods appear to be advantageous only at the tails of the distribution. More sophisticated bias correction based methods are needed to remove the biases in the higher-order statistics of the GCM outputs. The two calibration strategies led to fundamentally different temporal structures and spatial variability of the downscaled climatic variables. Bias correction based methods produced larger uncertainty bounds of inter-annual variability than the change factor methods. For downscaled precipitation, the uncertainty arising from the downscaling methods is comparable to the uncertainty arising from GCMs, while more uncertainty is introduced by calibration strategies than statistical transformation methods. There is a growing consensus that the performance of hydrological models should be routinely evaluated before being used in impact-related studies. The uncertainty, which stems from transferring calibrated models to a changing future climate, is receiving increasing attention. Chapter 4 assesses the uncertainties associated with the parameter calibration of the lumped Xinanjiang hydrological model when assessing the climate change impacts on river flow. The transferability of model parameters was tested in the context of historical climate variability using the differential split-sample test. The parameters calibrated from the periods representing differing climatic conditions were used to project future river flow in a changing climate. The uncertainties in projected future river flows stemming from the choice of calibration periods and parameter equifinality were compared. The results show that the transferability of the parameters calibrated from a wet period to a dry period is poorer than the other way around. The model error as well as the variability in the simulations due to equifinality increase with the increase of the difference in rainfall between the calibration and validation periods. The uncertainty due to the choice of calibration periods takes the majority of the total parameter uncertainty in the projected future mean discharge. When the calibration period contains enough information on climate variability, the equifinality effect and the choice of calibration periods contribute comparable magnitudes of uncertainty in terms of extreme discharge. Five sources of uncertainty mentioned above were compared in Chapter 5, i.e. GCM structure, greenhouse gas emission scenario, downscaling method, choice of period for calibrating the hydrological model, and non-uniqueness of hydrological parameters. Multiple samples of flood frequency curves were generated through the combinations of different emission scenarios, GCMs, downscaling methods and hydrological model settings. All samples were given equal weights in the analysis. The results show that the future flood magnitude is expected to increase, not only due to the increase in mean precipitation, but also due to the increase in variation of precipitation. Nonetheless, there is still a small likelihood that the flood quantiles with a high return period (above 20 years) will decrease in the future. The results of uncertainty comparison suggest that the GCM structure is the dominant source of uncertainty, emission scenarios and empirical statistical downscaling methods also result in considerable uncertainty, and the uncertainties related to hydrological model are less than those related to other uncertainty sources. To guarantee a safe flood defence in a changing environment, the adaptation to climate change needs to be considered in the design of river dikes. However, the large uncertainty in the projections of the future climate leads to varied estimations of future flood probability. How to cope with the uncertainties in future flood probability under climate change is an inevitable question in adaptation decision-makings. In Chapter 6, the uncertainty introduced by climate projections was integrated into the ‘expected predictive flood probability’, and the risk-aversion attitude was introduced in the adaptation of river dikes. The uncertainty in the climate change projections on flood probability was represented by the uncertainty in the parameters of the probabilistic model. This parameter uncertainty was estimated based on the outputs from the GCMs participating in IPCC AR4. The parameter uncertainty, estimated from the selected GCMs under different scenarios, was integrated into the expected predictive probability of flooding, which was then used in the risk-averse economic optimization. Different optimal results were obtained based on varied values of the risk-aversion index which represents the risk-averse altitude of decision makers. The case of a dike ring area in the Bengbu City in the Huai River Basin is studied as an example using the proposed approach. The results show that the uncertainty of climate change decreases the optimal safety level and increases the optimal dike heightening up to 8.23 m (with the risk-aversion index of 1.5) in a gradually changing climate. The value would be even larger if the climate will change sooner. Integrated adaptive measures rather than only dike heightening are needed to respond to the uncertain impacts in the future. The proposed approach enables decision makers to cope with climate change and the associated uncertainty by adjusting the level of risk aversion.","climate change; river flood frequency; uncertainty; adaptatioin","en","doctoral thesis","VSSD","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:9a40d3e8-f2a4-403f-99fe-0043f3214e74","http://resolver.tudelft.nl/uuid:9a40d3e8-f2a4-403f-99fe-0043f3214e74","Deriving root zone storage capacity from Earth observation","Wang, L.; Gao, H.; Bastiaanssen, W.G.M.; Jagermeyr, J.; Keys, P.","","2015","","","en","journal article","European Geosciences Union (EGU)","","","","","","","","Civil Engineering and Geosciences","Water Management","","","",""
"uuid:0e96f153-0e18-4211-b464-ebd6cb41c865","http://resolver.tudelft.nl/uuid:0e96f153-0e18-4211-b464-ebd6cb41c865","An integrated approach for efficient biomethane production from solid bio-wastes in a compact system","Wang, H.; Tao, Y.; Temudo, M.; Schooneveld, M.; Bijl, H.; Ren, N.; Wolf, M.; Heine, C.; Foerster, A.; Pelenc, V.; Kloek, J.; Van Lier, J.B.; De Kreuk, M.K.","","2015","Background Solid bio-wastes (or organic residues) are worldwide produced in high amount and increasingly considered bioenergy containers rather than waste products. A complete bioprocess from recalcitrant solid wastes to methane (SW2M) via anaerobic digestion (AD) is believed to be a sustainable way to utilize solid bio-wastes. However, the complex and recalcitrance of these organic solids make the hydrolysis process inefficient and thus a rate-limiting step to many AD technologies. Effort has been made to enhance the hydrolysis efficiency, but a comprehensive assessment over a complete flow scheme of SW2M is rare. Results In this study, it comes to reality of a complete scheme for SW2M. A novel process to efficiently convert organic residues into methane is proposed, which proved to be more favorable compared to conventional methods. Brewers’ spent grain (BSG) and pig manure (PM) were used to test the feasibility and efficiency. BSG and PM were enzymatically pre-hydrolyzed and solubilized, after which the hydrolysates were anaerobically digested using different bioreactor designs, including expanded granular sludge bed (EGSB), continuously stirred tank reactor (CSTR), and sequencing batch reactor (SBR). High organic loading rates (OLRs), reaching 19 and 21 kgCOD?·?m?3?·?day?1 were achieved for the EGSBs, fed with BSG and PM, respectively, which were five to seven times higher than those obtained with direct digestion of the raw materials via CSTR or SBR. About 56% and 45% organic proportion of the BSG and PM can be eventually converted to methane. Conclusions This study proves that complex organic solids, such as cellulose, hemicellulose, proteins, and lipids can be efficiently hydrolyzed, yielding easy biodegradable/bio-convertible influents for the subsequent anaerobic digestion step. Although the economical advantage might not be clear, the current approach represents an efficient way for industrial-scale treatment of organic residues with a small footprint and fast conversion of AD.","OA-Fund TU Delft","en","journal article","BioMed Central","","","","","","","","Civil Engineering and Geosciences","Water Management","","","",""
"uuid:969fbfe8-ad32-4e19-be6c-6f09641ae226","http://resolver.tudelft.nl/uuid:969fbfe8-ad32-4e19-be6c-6f09641ae226","Epidemics in interconnected small-world networks","Liu, M.; Li, D.; Qin, P.; Liu, C.; Wang, H.; Wang, F.","","2015","Networks can be used to describe the interconnections among individuals, which play an important role in the spread of disease. Although the small-world effect has been found to have a significant impact on epidemics in single networks, the small-world effect on epidemics in interconnected networks has rarely been considered. Here, we study the susceptibleinfected-susceptible (SIS) model of epidemic spreading in a system comprising two interconnected small-world networks. We find that the epidemic threshold in such networks decreases when the rewiring probability of the component small-world networks increases. When the infection rate is low, the rewiring probability affects the global steady-state infection density, whereas when the infection rate is high, the infection density is insensitive to the rewiring probability. Moreover, epidemics in interconnected small-world networks are found to spread at different velocities that depend on the rewiring probability.","","en","journal article","Public Library of Science PLOS","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Intelligent Systems","","","",""
"uuid:13da8732-07ef-48cc-a5f8-fbbd4f70b0b0","http://resolver.tudelft.nl/uuid:13da8732-07ef-48cc-a5f8-fbbd4f70b0b0","Correlation between centrality metrics and their application to the opinion model","Li, C.; Li, Q.; Van Mieghem, P.F.A.; Stanley, H.E.; Wang, H.","","2015","In recent decades, a number of centrality metrics describing network properties of nodes have been proposed to rank the importance of nodes. In order to understand the correlations between centrality metrics and to approximate a high-complexity centrality metric by a strongly correlated low-complexity metric, we first study the correlation between centrality metrics in terms of their Pearson correlation coefficient and their similarity in ranking of nodes. In addition to considering the widely used centrality metrics, we introduce a new centrality measure, the degree mass. The mth-order degree mass of a node is the sum of the weighted degree of the node and its neighbors no further than m hops away. We find that the betweenness, the closeness, and the components of the principal eigenvector of the adjacency matrix are strongly correlated with the degree, the 1st-order degree mass and the 2nd-order degree mass, respectively, in both network models and real-world networks. We then theoretically prove that the Pearson correlation coefficient between the principal eigenvector and the 2nd-order degree mass is larger than that between the principal eigenvector and a lower order degree mass. Finally, we investigate the effect of the inflexible contrarians selected based on different centrality metrics in helping one opinion to compete with another in the inflexible contrarian opinion (ICO) model. Interestingly, we find that selecting the inflexible contrarians based on the leverage, the betweenness, or the degree is more effective in opinion-competition than using other centrality metrics in all types of networks. This observation is supported by our previous observations, i.e., that there is a strong linear correlation between the degree and the betweenness, as well as a high centrality similarity between the leverage and the degree.","statistical and nonlinear physics","en","journal article","Springer","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Intelligent Systems","","","",""
"uuid:e466fb81-0d17-44f6-8d92-0c9cb5a73a7f","http://resolver.tudelft.nl/uuid:e466fb81-0d17-44f6-8d92-0c9cb5a73a7f","On-line Distributed Prediction and Control for a Large-scale Traffic Network","Wang, Y.","Brazier, F.M.T. (promotor); van Schuppen, J.H. (promotor); Vrancken, J.L.M. (promotor)","2015","Traffic becomes more congested due to the growing demand. As a consequence, improving traffic flow by means of traffic control is a key focus in many countries. However, road traffic is one of the most complex systems to control. In this thesis, a distributed solution for traffic prediction and control is proposed to reduce this complexity and achieve fast computation for the purpose of on-line usage in a large-scale network.","distributed prediction; distrubuted control; traffic; demand prediction; multilevel control","en","doctoral thesis","TRAIL","","","","","","","","Technology, Policy and Management","Multi Actor Systems","","","",""
"uuid:435efdda-601d-4ede-95a9-b49576c02d23","http://resolver.tudelft.nl/uuid:435efdda-601d-4ede-95a9-b49576c02d23","MAX-DOAS observations of aerosols, formaldehyde and nitrogen dioxide in the Beijing area: Comparison of two profile retrieval approaches","Vlemmix, T.; Hendrick, F.; Pinardi, G.; De Smedt, I.; Fayt, C.; Hermans, C.; Piters, A.; Wang, P.; Levelt, P.F.; Van Roozendael, M.","","2015","A 4-year data set of MAX-DOAS observations in the Beijing area (2008–2012) is analysed with a focus on NO2, HCHO and aerosols. Two very different retrieval methods are applied. Method A describes the tropospheric profile with 13 layers and makes use of the optimal estimation method. Method B uses 2–4 parameters to describe the tropospheric profile and an inversion based on a least-squares fit. For each constituent (NO2, HCHO and aerosols) the retrieval outcomes are compared in terms of tropospheric column densities, surface concentrations and ""characteristic profile heights"" (i.e. the height below which 75% of the vertically integrated tropospheric column density resides). We find best agreement between the two methods for tropospheric NO2 column densities, with a standard deviation of relative differences below 10%, a correlation of 0.99 and a linear regression with a slope of 1.03. For tropospheric HCHO column densities we find a similar slope, but also a systematic bias of almost 10% which is likely related to differences in profile height. Aerosol optical depths (AODs) retrieved with method B are 20% high compared to method A. They are more in agreement with AERONET measurements, which are on average only 5% lower, however with considerable relative differences (standard deviation ~ 25%). With respect to near-surface volume mixing ratios and aerosol extinction we find considerably larger relative differences: 10 ± 30, ?23 ± 28 and ?8 ± 33% for aerosols, HCHO and NO2 respectively. The frequency distributions of these near-surface concentrations show however a quite good agreement, and this indicates that near-surface concentrations derived from MAX-DOAS are certainly useful in a climatological sense. A major difference between the two methods is the dynamic range of retrieved characteristic profile heights which is larger for method B than for method A. This effect is most pronounced for HCHO, where retrieved profile shapes with method A are very close to the a priori, and moderate for NO2 and aerosol extinction which on average show quite good agreement for characteristic profile heights below 1.5 km. One of the main advantages of method A is the stability, even under suboptimal conditions (e.g. in the presence of clouds). Method B is generally more unstable and this explains probably a substantial part of the quite large relative differences between the two methods. However, despite a relatively low precision for individual profile retrievals it appears as if seasonally averaged profile heights retrieved with method B are less biased towards a priori assumptions than those retrieved with method A. This gives confidence in the result obtained with method B, namely that aerosol extinction profiles tend on average to be higher than NO2 profiles in spring and summer, whereas they seem on average to be of the same height in winter, a result which is especially relevant in relation to the validation of satellite retrievals.","","en","journal article","European Geosciences Union (EGU)","","","","","","","","Civil Engineering and Geosciences","Geoscience & Remote Sensing","","","",""
"uuid:7e895267-a951-4d7b-92e0-fb92eb9777a4","http://resolver.tudelft.nl/uuid:7e895267-a951-4d7b-92e0-fb92eb9777a4","MAX-DOAS observations of aerosols, formaldehyde and nitrogen dioxide in the Beijing area: Comparison of two profile retrieval approaches","Vlemmix, T. (TU Delft Atmospheric Remote Sensing; Royal Belgian Institute for Space Aeronomy (BIRA-IASB)); Hendrick, F (Royal Belgian Institute for Space Aeronomy (BIRA-IASB)); Pinardi, G (Royal Belgian Institute for Space Aeronomy (BIRA-IASB)); De Smedt, I (Royal Belgian Institute for Space Aeronomy (BIRA-IASB)); Fayt, C (Royal Belgian Institute for Space Aeronomy (BIRA-IASB)); Hermans, C. (Royal Belgian Institute for Space Aeronomy (BIRA-IASB)); Piters, AJM (Royal Netherlands Meteorological Institute (KNMI)); Wang, P. (Chinese Academy of Sciences); Levelt, Pieternel Felicitas (TU Delft Atmospheric Remote Sensing; Royal Netherlands Meteorological Institute (KNMI)); van Roozendael, M (Royal Belgian Institute for Space Aeronomy (BIRA-IASB))","","2015","A 4-year data set of MAX-DOAS observations in the Beijing area (2008-2012) is analysed with a focus on NO2, HCHO and aerosols. Two very different retrieval methods are applied. Method A describes the tropospheric profile with 13 layers and makes use of the optimal estimation method. Method B uses 2-4 parameters to describe the tropospheric profile and an inversion based on a least-squares fit. For each constituent (NO2, HCHO and aerosols) the retrieval outcomes are compared in terms of tropospheric column densities, surface concentrations and ""characteristic profile heights"" (i.e. the height below which 75% of the vertically integrated tropospheric column density resides). We find best agreement between the two methods for tropospheric NO2 column densities, with a standard deviation of relative differences below 10%, a correlation of 0.99 and a linear regression with a slope of 1.03. For tropospheric HCHO column densities we find a similar slope, but also a systematic bias of almost 10% which is likely related to differences in profile height. Aerosol optical depths (AODs) retrieved with method B are 20% high compared to method A. They are more in agreement with AERONET measurements, which are on average only 5% lower, however with considerable relative differences (standard deviation ∼ 25%). With respect to near-surface volume mixing ratios and aerosol extinction we find considerably larger relative differences: 10 ± 30, -23 ± 28 and -8 ± 33% for aerosols, HCHO and NO2 respectively. The frequency distributions of these near-surface concentrations show however a quite good agreement, and this indicates that near-surface concentrations derived from MAX-DOAS are certainly useful in a climatological sense. A major difference between the two methods is the dynamic range of retrieved characteristic profile heights which is larger for method B than for method A. This effect is most pronounced for HCHO, where retrieved profile shapes with method A are very close to the a priori, and moderate for NO2 and aerosol extinction which on average show quite good agreement for characteristic profile heights below 1.5 km. One of the main advantages of method A is the stability, even under suboptimal conditions (e.g. in the presence of clouds). Method B is generally more unstable and this explains probably a substantial part of the quite large relative differences between the two methods. However, despite a relatively low precision for individual profile retrievals it appears as if seasonally averaged profile heights retrieved with method B are less biased towards a priori assumptions than those retrieved with method A. This gives confidence in the result obtained with method B, namely that aerosol extinction profiles tend on average to be higher than NO2 profiles in spring and summer, whereas they seem on average to be of the same height in winter, a result which is especially relevant in relation to the validation of satellite retrievals.","","en","journal article","","","","","","","","","","","Atmospheric Remote Sensing","","",""
"uuid:67b34b4a-4116-4369-a4c4-bc956213a9c3","http://resolver.tudelft.nl/uuid:67b34b4a-4116-4369-a4c4-bc956213a9c3","Distinct mechanisms regulating mechanical force-induced Ca2+ signals at the plasma membrane and the ER in human MSCs","Kim, T.J.; Joo, C.; Seong, J.; Vafabakhsh, R.; Botvinick, E.L.; Berns, M.W.; Palmer, A.E.; Wang, N.; Ha, T.; Jakobsson, E.; Sun, J.; Wang, Y.","","2015","It is unclear that how subcellular organelles respond to external mechanical stimuli. Here, we investigated the molecular mechanisms by which mechanical force regulates Ca2+ signaling at endoplasmic reticulum (ER) in human mesenchymal stem cells. Without extracellular Ca2+, ER Ca2+ release is the source of intracellular Ca2+ oscillations induced by laser-tweezer-traction at the plasma membrane, providing a model to study how mechanical stimuli can be transmitted deep inside the cell body. This ER Ca2+ release upon mechanical stimulation is mediated not only by the mechanical support of cytoskeleton and actomyosin contractility, but also by mechanosensitive Ca2+ permeable channels on the plasma membrane, specifically TRPM7. However, Ca2+ influx at the plasma membrane via mechanosensitive Ca2+ permeable channels is only mediated by the passive cytoskeletal structure but not active actomyosin contractility. Thus, active actomyosin contractility is essential for the response of ER to the external mechanical stimuli, distinct from the mechanical regulation at the plasma membrane.","","en","journal article","eLife Sciences Publications","","","","","","","","Applied Sciences","BN/Bionanoscience","","","",""
"uuid:4787fb7d-3ff8-447a-acc9-4296d3628028","http://resolver.tudelft.nl/uuid:4787fb7d-3ff8-447a-acc9-4296d3628028","Slimmer aansturen van Adaptive Cruise Control-systemen","Wang, M.; Hoogendoorn, S.; Van Arem, B.; Daamen, W.","","2015","","","en","journal article","Stichting NM Magazine","","","","","","","","Civil Engineering and Geosciences","Transport & Planning","","","",""
"uuid:a254751d-3ec5-47b2-a971-47b3a4306c8d","http://resolver.tudelft.nl/uuid:a254751d-3ec5-47b2-a971-47b3a4306c8d","Turbid Flows and Their Deposits on Slopes with Minibasins: A Modelling Approach","Wang, X.","Luthi, S. (promotor)","2015","Passive continental margins display a great diversity of seafloor bathymetries induced by gravity driven extensional faulting and compressional folding, as well as diapiric movements of salt or mud. In many diapirically controlled settings, slope bathymetries are complicated and characterized by numerous ridges, trenches and minibasins such as in the Gulf of Mexico and offshore West Africa. These bathymetries play a significant role in controlling turbidity current behavior, the resulting sediment distribution and the internal architecture. Numerous researchers have investigated the influence of pre-existing or developing minibasins on the behaviour of turbidity currents and the resulting depositional systems using seismic data, analogue field outcrops, and laboratory and numerical experiments. The classic fill-spill model was proposed to describe the depositional process in linked intraslope minibasins in the Gulf of Mexico. However, due to the inherent limitations of present-day geophysical techniques and the limited exposure of field outcrops, the small-scale internal architecture and stacking pattern of such confined or semi-confined turbidite systems are still not well understood. The objective of this thesis is to better understand the interaction between flow, sediment and topography, and attempt to develop conceptual models for the changes in sediment dispersal and stacking patterns in diapirically controlled minibasins on passive margins. In order to achieve this, we combine laboratory analogue modelling of intraslope minibasins with numerical flow simulations of multi-event turbidity currents. Previous studies on salt tectonics show that minibasins can be bounded by fold-and-fault systems or are sitting above allochthonous or autochthonous salt bodies. Gravity gliding explains well the typical structural zones (extensional, transitional and compressional) of passive margins, and therefore, in our studies, we conducted analogue tectonic sandbox experiments in which the deformations are driven gravity gliding. Sand and silicone putty are used to represent the prekinematic sediment and salt respectively. The experimental results from different setups show that three types of minibasins are formed and distinguished according to their boundary contact relationships: MB1 (no contact with the silicone layer), MB2 (the silicone layer as the basin base) and MB3 (the silicone diapir as the basin flank). The resulting topographies are scanned with a laser beam from which a digital elevation model is obtained. One topography that is considered most realistic is selected and upscaled to dimensions that typically occur in nature. Furthermore, a channel is added on the shelf and the shelf break to serve as point source for the flows. Subsequently, a numerical flow simulation software (“FanBuilder”, Groenenberg et al., 2009) is employed to model multi-event low-density turbidity currents that flow from the incised channel down into the minibasins on the continental margin. A series of sets of parameters within ranges expected to occur in nature were compiled from literature study and used for the flow simulation experiments. Multiple flow events (non-equilibrium and equilibrium flows) from the same point source were run whereby the deposits were stacked on top of its predecessor. The resulting stratigraphy is then analyzed in 3-D, typically in a series of strike and dip sections. The experimental results of a series of numerical simulations are compared and discussed in terms of flow evolution, flow-deposit interaction, and internal architecture and stacking patterns. In our models, the turbidity currents show a behaviour that can be divided into three phases: the ponding, the fill-and-spill, and the trapping stages. A significant grain-size partitioning happens at the early fill-and-spill stage, with the coarser grains getting trapped in the up-dip minibasin and finer grains transported by the spillover flows further downslope. Significant deposition in the minibasin takes place on the counterslope after the first minibasin depression. The flow pathway and evolution depend much on the flow volume reaching the up-dip minibasin, the remaining accommodation space, and the topography geometry and gradient. The deposits can smooth the gradient of the counterslope, allow more spillover, but they can also make the bounding ridge grow and move upstream and thereby restrict the flows to the minibasin. Overall, the turbidite system undergoes a sequence of progradation followed by aggradation and retrogradation. A sequence of coarsening- and thickening-upward trends is dominant in the down-dip minibasins, while the upper minibasin shows different sequences at different locations. The group depocenters in three minibasins all migrate towards upstream longitudinally and to the minibasin center laterally, which results in a back-filling stacking pattern. Some supportive evidence from published literature has been found to validate our main results. Recommendations for future research include seismic or outcrop studies, syn-tectonic sedimentation experiments, and numerical simulations of high-density gravity flows.","turbidity currents; turbidites; passive margin; minibasin; flow-deposit interaction; compensational pattern","en","doctoral thesis","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""
"uuid:63a8269c-0726-479c-a5db-003c4128d6f1","http://resolver.tudelft.nl/uuid:63a8269c-0726-479c-a5db-003c4128d6f1","Connected variable speed limits control and vehicle acceleration control to resolve moving jams","Wang, M.; Daamen, W.; Hoogendoorn, S.P.; Van Arem, B.","","2015","The vision of intelligent vehicles traveling in road networks has prompted numerous concepts to control future traffic flow, one of which is the in-vehicle actuation of traffic control signals. The key of this concept is using intelligent vehicles as actuators for traffic control systems, replacing the traditional road-side systems. Under this concept, the authors design and test a control system that connects a traffic controller with in-vehicle controllers with Vehicle-to-Infrastructure communications. The link-level traffic controller regulates traffic speeds through variable speed limits (VSL) gantries to resolve stop-and-go waves, while intelligent vehicles control accelerations through vehicle propulsion and brake systems to optimize their local situations. It is assumed that each intelligent vehicle receives VSL commands from the traffic controller and uses them as variable parameters for the local vehicle controller. Feasibility and effectiveness of the connected control paradigm are tested in simulation on a two-lane freeway stretch with intelligent vehicles randomly distributed among human-driven vehicles. Simulation shows that the connected VSL and vehicle control system improves traffic efficiency and sustainability, i.e. total time spent in the network and average fuel consumption rate are reduced compared to (uncontrolled and controlled) scenarios with 100% human drivers and to uncontrolled scenarios with the same intelligent vehicle penetration rates.","","en","conference paper","TRB","","","","","","","","Civil Engineering and Geosciences","Transport & Planning","","","",""
"uuid:da8eb725-e838-4dc7-9da1-10f319261715","http://resolver.tudelft.nl/uuid:da8eb725-e838-4dc7-9da1-10f319261715","Operability of floating bulk transhipment operation","Wang, Yijun","Huijsmans, R.H.M. (mentor)","2015","","","","master thesis","","","","","","","","2100-08-01","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Offshore and Dredging Engineering","","",""
"uuid:1ce0cb99-34dc-4e05-b4b9-cf5c7304b1d1","http://resolver.tudelft.nl/uuid:1ce0cb99-34dc-4e05-b4b9-cf5c7304b1d1","Integrated Stiffness Analysis of Redundant Parallel Manipulator Based on Finite Element Method","Wang, S.; Cheng, G.; Pang, Y.; Lodewijks, G.","","2015","An integrated stiffness model is established for a Planar Parallel Manipulator (PPM) with actuation redundancy based on Finite Element Method (FEM), and the static stiffness, dynamitic stiffness and moving stiffness of the PPM are analyzed according to the integrated stiffness model. Firstly, a dynamic model of flexible plane beam element is created as a basic unit for branches. Secondly, each branch is assembled in generalized coordinates, and the integrated stiffness model of the PPM is established. Then calculation and simulation for the static stiffness, dynamitic stiffness and moving stiffness are carried out. The results show that the static stiffness and dynamitic stiffness are related with the position and posture of the PPM. The moving stiffness shows that the elastic deformations cause the oscillation of the PPM. In this paper, three stiffness models are unified in the integrated stiffness model, which improves the efficiency of the stiffness calculation and mechanism design.","parallel manipulator; Finite Element Method; integrated stiffness; dynamics","en","journal article","Binary Information Press","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","","","",""
"uuid:b3cd0fa8-c8f3-4a56-92c0-0be5a2289ecd","http://resolver.tudelft.nl/uuid:b3cd0fa8-c8f3-4a56-92c0-0be5a2289ecd","Multibody dynamic analysis of the lift-off operation","Wang, S.","van Dalen, K.N. (mentor)","2015","","","","master thesis","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Offshore and Dredging Engineering","","",""
"uuid:c90c7a12-6456-4589-89a6-9448b6f33258","http://resolver.tudelft.nl/uuid:c90c7a12-6456-4589-89a6-9448b6f33258","Influence of wall proximity on flow around two tandem circular cylinders","Wang, X.K.; Zhang, J.-X.; Zhou, B.; Tan, S.K.","","2015","","hydrodynamics","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:b5298f37-eeb3-47f2-b43c-e03c016eae79","http://resolver.tudelft.nl/uuid:b5298f37-eeb3-47f2-b43c-e03c016eae79","Distinct mechanisms regulating mechanical force-induced Ca2+ signals at the plasma membrane and the endoplasmic reticulum in human mesenchymal stem cells","Kim, SH (University of Illinois); Joo, C. (TU Delft BN/Chirlmin Joo Lab); Seong, A (External organisation); Vafabakshsh, A (External organisation); Botvinick, A (External organisation); Berns, A (External organisation); Palmer, TA (External organisation); Wang, Z. (External organisation); Ha, Seungkyu; Jakobsson, ME; Sun, M (External organisation)","","2015","It is unclear that how subcellular organelles respond to external mechanical stimuli. Here, we investigated the molecular mechanisms by which mechanical force regulates Ca2+ signaling at endoplasmic reticulum (ER) in human mesenchymal stem cells. Without extracellular Ca2+, ER Ca2+ release is the source of intracellular Ca2+ oscillations induced by laser-tweezer-traction at the plasma membrane, providing a model to study how mechanical stimuli can be transmitted deep inside the cell body. This ER Ca2+ release upon mechanical stimulation is mediated not only by the mechanical support of cytoskeleton and actomyosin contractility, but also by mechanosensitive Ca2+ permeable channels on the plasma membrane, specifically TRPM7. However, Ca2+ influx at the plasma membrane via mechanosensitive Ca2+ permeable channels is only mediated by the passive cytoskeletal structure but not active actomyosin contractility. Thus, active actomyosin contractility is essential for the response of ER to the external mechanical stimuli, distinct from the mechanical regulation at the plasma membrane.","","en","journal article","","","","","","","","","","","BN/Chirlmin Joo Lab","","",""
"uuid:454b7ac4-1e82-46b5-a2e6-668bcb3b1821","http://resolver.tudelft.nl/uuid:454b7ac4-1e82-46b5-a2e6-668bcb3b1821","A transferable force field for CdS-CdSe-PbS-PbSe solid systems","Fan, Z.; Koster, R.S.; Wang, S.; Fang, C.; Yalcin, A.O.; Tichelaar, F.D.; Zandbergen, H.W.; Van Huis, M.A.; Vlugt, T.J.H.","","2014","","","en","journal article","AIP Publishing","","","","","","","","Mechanical, Maritime and Materials Engineering","Process and Energy","","","",""
"uuid:938087b8-19b7-4bcb-9ffb-4757e11f8533","http://resolver.tudelft.nl/uuid:938087b8-19b7-4bcb-9ffb-4757e11f8533","Global-local Knowledge Coupling Approach to Support Airframe Structural Design","Wang, H.","Van Tooren, M.J.L. (promotor)","2014","The outsourcing that has taken place in the aircraft industry over the last few decades has created a globalized supply chain from and to a limited number of original equipment manufacturers (OEMs). This has led to multi-level design due to the shift from airframe subsystem design to suppliers. Increasingly OEMs focus on requirement allocation and definition of airframe subsystems and verification at a global level, whereas suppliers focus on the realization and improvement of airframe subsystems at the local level. Relying on a supply chain for innovative designs and builds can cause OEMs to have insufficient bottom-up knowledge about subsystem design, in particular, the innovative local designs, e.g. composites and new production methods, however, in the overall aircraft conceptual design phase, the analysis and evaluation of different subsystem designs, by OEM internally, rely heavily on assumptions and estimations which are usually based on statistical/empirical data. Although global designs can be quickly analyzed using assumptions and estimates, this risks costly design changes if the assumptions and estimations are proven incorrect in the later overall aircraft design phases. Suppliers who have detail-level knowledge should be involved early in the overall aircraft conceptual design phase, creating various local designs, and conducting more accurate analyses and evaluations of these designs. Early local design studies can help suppliers help OEMs to reduce the risk of design changes related to incorrect assumptions and estimations, and convince OEMs of the benefits of new material and new production methods. The objective of this research was to develop a design approach which can support suppliers to perform local design fast from which critical results, i.e. cost and weight, can be generated during the overall aircraft conceptual design phase. A fast airframe subsystem design is highly beneficial for suppliers wishing to increase their competiveness, providing fast response and being flexible in the overall aircraft conceptual design phase. It is also beneficial for OEMs to reduce the risk of design changes due to incorrect assumptions and estimations. Several issues in the current design process that hamper a fast study of airframe subsystems were identified in this research, some of which have to be addressed from the supplier’s side. 1) The dependency of suppliers on the OEMs to get coherent, consistent and timely design information, e.g. geometry and load cases, needed to start local design. This dependency causes suppliers wait until all the required information is available from the OEMs in the overall aircraft preliminary design phase. Therefore, the suppliers cannot proactively participate in the overall aircraft conceptual design, in which the airframe subsystem design relies heavily on assumptions and estimations. 2) The manual processes used by suppliers to update computer aided design (CAD) and analysis models to follow design changes at the global and local level. In the overall aircraft conceptual design phase, both the global and local design are not fixed yet and tend to change. Manually model updating at local design level takes significant engineering efforts, and hence slows down the supplier’s response to the changes in the global design. 3) There is a lack of multidisciplinary design optimization (MDO) capability and capacity at a local design level due to this lack of MDO knowledge and a lack of tools to build parametric product and process models. Therefore, in the short conceptual design phase, suppliers often just deliver a (few) feasible design solution(s) instead of a family of Pareto design solutions. To address these issues, and hence to increase supplier competitiveness, a global-local knowledge coupling approach is proposed, which comprises two modules at the global and local design level. The module at global design level is the cross-over, which is used as a substitute for global design and provides the inputs required for starting a local design. The cross-over is used to make the global and local designs concurrent in the early aircraft design phase. The module at the local design level is a set of parametric product and process models of airframe subsystems used to automate repetitive design actions at local design level, such that the analysis and evaluation of subsystem designs can be quickly performed. Knowledge based engineering (KBE) is adopted to implement the two modules for two main purposes: 1) parameterization of product models that allows automatic model (re)generation; 2) automation of pre-processing to prepare inputs for disciplinary analysis tools. Multidisciplinary design optimization is used as the technical implementation mean of the proposed approach to automate the process of finding an optimal design for a complex airframe subsystem. Three demonstration systems are developed, each of them formed as a design framework, called the Airframe Design and Engineering Engine (ADEE), which is a specialized Design and Engineering Engine (DEE). The design and engineering engine (Tooren, 2003) is a MDO system aimed at supporting and accelerating the design process of complex products, through the automation of non-creative and repetitive design activities. The verification design systems are the fuselage ADEE, the fuselage panel ADEE and the movable ADEE. One of the main contributions of this research is to identify the issues in the airframe design process which involves OEM and suppliers, and how these issues can be solved for quickly performing local design in the aircraft conceptual design phase. Another contribution lies in the development of the global-local knowledge coupling approach and its demonstration systems for the new design approach, which provide tools and methods to address these issues. Each verification tool is an ADEE, which is supported by KBE to perform global design and local design in an automatic fashion, such that cross-over can quickly generate the required inputs for local design and the local design module can quickly generate and analyse various subsystem design variants. The fuselage ADEE is used to address issue 1 by increasing design independence for panel suppliers The fuselage ADEE is implemented as a cross-over, in which finite element analysis (FEA) based weight estimation is developed to capture the effects of material and structural layout on fuselage weight. The global knowledge is captured in the cross-over, including the knowledge of how to generate fuselage outer mould line (OML) and knowledge of how to perform disciplinary analysis such as load calculation and structural analysis using FEA. The ADEE is validated using data from fuselages of conventional aircraft such as the ATR 42, Fokker 100, Boeing 737-200, Airbus A320-200 and Airbus A300B2. The fuselage ADEE is also used to estimate fuselage weight of a joint wing aircraft. The fuselage panel ADEE is used to address issue 2 by automating repetitive model (re)generation for local design The fuselage panel ADEE is the local design module of the global-local knowledge coupling, which comprises a parametric panel product model and disciplinary analysis models, i.e. structural analysis, cost estimation and weight evaluation models. The fuselage ADEE is a cross-over which provides inputs for the fuselage panel ADEE. A KBE-enabled parametric panel product model is implemented in the fuselage panel ADEE to model various configurations of fuselage panels flexibly, which are composed of skin with multiple layers and back-up structural members, such as frames and stringers. These structural members are modeled based on the OML generated by the fuselage ADEE. The structural analysis uses global-local FEA in which a global FE model is obtained from the cross-over to predict the overall fuselage behavior, whereas a refined FE panel model is built for investigating panel behavior. The local panel process knowledge is captured in the panel ADEE so as to automate the panel modeling, structural analysis, parametric bottom-up cost estimation and weight evaluation. Using the accelerated local panel design process, the local panel design can quickly respond to the change of global design, while the model consistency between global and local levels can be guaranteed. The movable ADEE is used to address issue 3 by automating repetitive design actions in the MDO process The movable ADEE is developed to perform cost/weight multi-objective optimization of movable structures, e.g. rudders and elevators, including large topology variations of the structural configuration. The KBE-enabled modelling module of this ADEE is able to model very different product configurations and variants and extract all data required to feed the weight and cost estimation modules, in a fully automated fashion. The weight estimation method uses FEA to calculate the internal stresses of the structural elements and an analytical composite plate sizing method to determine their minimum required thicknesses. The manufacturing cost estimation module was developed on the basis of a cost model available in the literature. The capability of the framework is successfully demonstrated by designing and optimizing the composite structure of a business jet rudder. The study case indicates that this ADEE is able to find the Pareto optimal set for minimum structural weight and manufacturing cost quickly. The demonstration systems developed demonstrate that the global-local knowledge coupling approach can support suppliers wishing to perform fast airframe subsystem design in the overall aircraft conceptual design phase.","","en","doctoral thesis","","","","","","","","2014-12-24","Aerospace Engineering","Flight Performance and Propulsion","","","",""
"uuid:911bbe04-acf6-4d5e-8e22-740da3b1a166","http://resolver.tudelft.nl/uuid:911bbe04-acf6-4d5e-8e22-740da3b1a166","Shaping vibrant urban places in Chinese inner-city station areas: A case study of Beijing West station areas","Wang, X.","","2014","Cities in China are embarked on ambitions plans to create renewed inner-city station areas, particularly evident after a series of redevelopment projects; these projects mainly focus on the development of transport infrastructures, rather than turning station areas into vibrant urban spaces. Therefore, a general lack of citizen’s daily activities have turned these areas into urban ‘enclaves’, which are merely transport nodes with interior spaces only used by travellers, rather enclosed and segregated from their surroundings. Through the study of the spatial characters of Beijing West station area, a typical project model in Chinese urban context, this paper aims to clearly reveal the spatial failures of Chinese problematic. Conclusions are three recommendations for future redevelopments to improve urban vitality of inner-city station areas in China.","inner-city station areas; spatial performance; urban vitality; station area redevelopment in China","en","conference paper","The Architectural Science Association & Genova University Press","","","","","","","","Architecture and The Built Environment","Architecture","","","",""
"uuid:dcc6469c-016d-44ae-b8fd-009dfcc3b90b","http://resolver.tudelft.nl/uuid:dcc6469c-016d-44ae-b8fd-009dfcc3b90b","Thermoelectricity and disorder of FeCo/MgO/FeCo magnetic tunnel junctions","Wang, S.Z.; Xia, K.; Bauer, G.E.W.","","2014","We compute the thermoelectric transport parameterized by the Seebeck coefficient and thermal/electric conductance of random-alloy FeCo/MgO/FeCo(001) magnetic tunnel junctions (MTJs) from first principles using a generalized Landauer-Büttiker formalism. The thermopower is found to be typically smaller than those of Fe/MgO/Fe(001) MTJs. The (magneto-)Seebeck effect is sensitive to the details of the FeCo/MgO interfaces. Interfacial can greatly enhance the thermoelectric effects in MTJs. We also compute angular-dependent Seebeck coefficients that provide additional information about the transport physics. We report large deviations from the Wiedemann-Franz law at room temperature.","","en","journal article","American Physical Society","","","","","","","","Applied Sciences","QN/Quantum Nanoscience","","","",""
"uuid:bf0babd8-2e6d-40f5-b805-a629a4160ae3","http://resolver.tudelft.nl/uuid:bf0babd8-2e6d-40f5-b805-a629a4160ae3","Chaotic Dynamics in Smart Grid and Suppression Scheme via Generalized Fuzzy Hyperbolic Model","Sun, Q.; Wang, Y.; Yang, J.; Qiu, Y.; Zhang, H.","","2014","This paper presents a method to control chaotic behavior of a typical Smart Grid based on generalized fuzzy hyperbolic model (GFHM). As more and more distributed generations (DG) are incorporated into the Smart Grid, the chaotic behavior occurs increasingly. To verify the behavior, a dynamic model which describes a power system with DG is presented firstly. Then, the simulation result shows that the power system can lead to chaos under certain initial conditions. Based on the universal approximation of GFHM, we confirm that the chaotic behavior could be suppressed by a new controller, which is designed by means of solving a linear matrix inequality (LMI). This approach could make a good application to suppress the chaos in Smart Grid. Finally, a numerical example is given to demonstrate the effectiveness of the proposed chaotic suppression strategy.","","en","journal article","Hindawi","","","","","","","","Mechanical, Maritime and Materials Engineering","Delft Center for Systems and Control","","","",""
"uuid:2d5e96b7-8606-4378-be33-71ac160b38a4","http://resolver.tudelft.nl/uuid:2d5e96b7-8606-4378-be33-71ac160b38a4","Turbidity maximum formation in a well-mixed macrotidal estuary: The role of tidal pumping","Yu, Q.; Wang, Y.; Gao, J.; Gao, S.; Flemming, B.","","2014","Traditionally, vertical circulation (induced by gravity circulation and tidal straining), tidal pumping, and resuspension are suggested as the major processes for the formation and maintenance of the estuarine turbidity maximum (ETM). Due to strong mixing, tidal pumping is considered as the dominating process in macrotidal estuaries. To analyze field observation data, the classical empirical decomposition method is commonly suggested, but the tidal pumping flux (TPF) based on this method may lead to erroneous conclusions about the mechanisms of ETM formation because the effects of advection induced by the horizontal SSC gradient and fine bed sediment supply are ignored. If these effects are included, the TPF clearly reproduces the convergence patterns and thus demonstrates its role in the formation of the ETM. By a simplified analytical solution, the TPF is the result of the competition between the downstream flux induced by the river current together with the lag in sediment response and the upstream flux induced by tidal asymmetry and the lag. Field observations in the well-mixed macrotidal Yalu River estuary (located between China and North Korea) were analyzed. Tidal pumping is identified as the dominant mechanism of its ETM formation, and the position of the ETM for different river discharges and sediment settling velocities can be predicted by the concept of tidal pumping by numerical and analytical procedures. The present study provides a typical example of how to evaluate the tidal pumping contributions on ETM formation using the combined information provided by field data, numerical modeling results, and analytical solutions.","estuarine turbidity maximum; well-mixed estuary; tidal pumping; Yalu River estuary","en","journal article","American Geophysical Union","","","","","","","2014-05-19","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:59069258-f7aa-4ab2-8805-4303a97c62dc","http://resolver.tudelft.nl/uuid:59069258-f7aa-4ab2-8805-4303a97c62dc","Active Affordance Learning in Continuous State and Action Spaces","Wang, C.; Hindriks, K.V.; Babuska, R.","","2014","Learning object affordances and manipulation skills is essential for developing cognitive service robots. We propose an active affordance learning approach in continuous state and action spaces without manual discretization of states or exploratory motor primitives. During exploration in the action space, the robot learns a forward model to predict action effects. It simultaneously updates the active exploration policy through reinforcement learning, whereby the prediction error serves as the intrinsic reward. By using the learned forward model, motor skills are obtained in a bottom-up manner to achieve goal states of an object. We demonstrate that a humanoid robot NAO is able to learn how to manipulate garbage cans with different lids by using different motor skills.","","en","conference paper","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Intelligent Systems","","","",""
"uuid:710bc559-b64c-4db2-ae53-7b0e525ba857","http://resolver.tudelft.nl/uuid:710bc559-b64c-4db2-ae53-7b0e525ba857","Nonconsensus opinion model on directed networks","Qu, B.; Li, Q.; Havlin, S.; Stanley, E.; Wang, H.","","2014","Dynamic social opinion models have been widely studied on undirected networks, and most of them are based on spin interaction models that produce a consensus. In reality, however, many networks such as Twitter and the World Wide Web are directed and are composed of both unidirectional and bidirectional links. Moreover, from choosing a coffee brand to deciding who to vote for in an election, two or more competing opinions often coexist. In response to this ubiquity of directed networks and the coexistence of two or more opinions in decision-making situations, we study a nonconsensus opinion model introduced by Shao et al. [Phys. Rev. Lett. 103, 018701 (2009)] on directed networks. We define directionality ? as the percentage of unidirectional links in a network, and we use the linear correlation coefficient ? between the in-degree and out-degree of a node to quantify the relation between the in-degree and out-degree. We introduce two degree-preserving rewiring approaches which allow us to construct directed networks that can have a broad range of possible combinations of directionality ? and linear correlation coefficient ? and to study how ? and ? impact opinion competitions. We find that, as the directionality ? or the in-degree and out-degree correlation ? increases, the majority opinion becomes more dominant and the minority opinion's ability to survive is lowered.","","en","journal article","American Physical Society","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Intelligent Systems","","","",""
"uuid:99413763-bd21-4d0a-98cd-f0154eb089c5","http://resolver.tudelft.nl/uuid:99413763-bd21-4d0a-98cd-f0154eb089c5","Inner-city station areas in Chinese cities","Wang, X.","","2014","Redevelopments of Chinese inner-?city station areas introduced both new transport infrastructures (high speed railway, urban mass transit system, etc.) and real estate projects to station vicinities during the past decades. However, existing station areas are isolated from the rest of the city, and seldom urban activities take place in station surroundings. This paper aims at exploring mechanisms behind the emergence of “urban isolation”. To this end, four relevant topics are discussed, namely urbanization in China, travel model shift in and between big cities, railway station operation and planning philosophy of inner?city station areas. Examining above aspects in some China’s big cities, especially in two typical station areas, Beijing West and Tianjin station areas, this paper examines why Chinese inner?city station areas have gained an increasing role as transport nodes but have paradoxically become isolated enclaves in city centers. Two recommendations are also generated out of above review and analysis.","inner-city railway station areas in China; redevelopment; urban isolation; mechanism","en","conference paper","","","","","","","","","Architecture and The Built Environment","Architecture","","","",""
"uuid:184a3ce5-ee63-4852-b9f5-c9f98dbaec42","http://resolver.tudelft.nl/uuid:184a3ce5-ee63-4852-b9f5-c9f98dbaec42","Transparency Performance in the 3D Visualization of Bounding Legal and Physical Objects: Preliminary Results of a Survey","Pouliot,, Jacynthe; Wang, Chen; Hubert, Frédéric","","2014","This paper presents a third, subsequent, experiment to assess the performance of various visual variables for better visualization of 3D cadastre models. The case study is a 3D spatial representation of an apartment building with co-ownership units. The third experiment focuses on the following hypotheses “Transparency is performing to distinguish two groups of bounding objects such as physical (e.g., walls) and legal (administrative units) and to give the impression of ownership”. These objects are distinct and essential for use by notaries, one category of user of 3D cadastre models, since the spatial relationships between them may directly influence the determination of ownership, and the associated rights and responsibilities. The methodology is based on online questionnaire showing twelve 3D models where participants are invited to test their ability to decide if the wall of a specific apartment belonged to them or not. For data analysis, groups of participants are categorized according to being skilled in cadastral data manipulation, and in 3D data visualization. This paper presents preliminary results of those tests.","Online Questionnaire; 3D Visualization; Properties Limits; Transparency Performance Analysis; Visual Variable Assessment","en","conference paper","","","","","","","","","","","","","",""
"uuid:855506a5-5a9c-41f5-aad0-42b015294348","http://resolver.tudelft.nl/uuid:855506a5-5a9c-41f5-aad0-42b015294348","Visualization, Distribution and Delivery of 3D Parcels: Position Paper 4","Pouliot, Jacynthe; Wang, Chen","","2014","This paper is the second of two position papers that serve as the basis for discussion in a forum held at the 4th International on 3D Cadastres, 9-11 November 2014, Dubai, UAE. The first paper was published in 2011 (Pouliot, 2011). The overall objective of the FIG Working Group discussion is to provide feedback to the FIG Commission 3 (Spatial Information Management) and FIG Commission 7 (Cadastre and Land Management) and EuroSDR. Four working sessions are planned; this paper applies to working session #4.","","en","conference paper","","","","","","","","","","","","","",""
"uuid:8b509ddb-ca42-4420-9b35-bc5543ae0d60","http://resolver.tudelft.nl/uuid:8b509ddb-ca42-4420-9b35-bc5543ae0d60","Forming of magnesium alloy microtubes in the fabrication of biodegradable stents","Wang, L.; Fang, G.; Qian, L.; Leeflang, M.A.; Duszczyk, J.; Zhou, J.","","2014","Magnesium alloys have, in recent years, been recognized as highly promising biodegradable materials, especially for vascular stent applications. Forming of magnesium alloys into high-precision thin-wall tubes has however presented a technological barrier in the fabrication of vascular stents, because of the poor workability of magnesium at room temperature. In the present study, the forming processes, i.e., hot indirect extrusion and multi-pass cold drawing were used to fabricate seamless microtubes of a magnesium alloy. The magnesium alloy ZM21 was selected as a representative biomaterial for biodegradable stent applications. Microtubes with an outside diameter of 2.9 mm and a wall thickness of 0.2 mm were successfully produced at the fourth pass of cold drawing without inter-pass annealing. Dimensional evaluation showed that multi-pass cold drawing was effective in correcting dimensional non-uniformity arising from hot indirect extrusion. Examinations of the microstructures of microtubes revealed the generation of a large number of twins as a result of accumulated work hardening at the third and fourth passes of cold drawing, corresponding to the significantly raised forming forces. The work demonstrated the viability of the forming process route selected for the fabrication of biodegradable magnesium alloy microtubes.","vascular stent; microtube; magnesium alloy; extrusion; drawing","en","journal article","Elsevier","","","","","","","","Mechanical, Maritime and Materials Engineering","Biomechanical Engineering","","","",""
"uuid:8eb074fa-3d47-4373-bf01-ffcee2a4612c","http://resolver.tudelft.nl/uuid:8eb074fa-3d47-4373-bf01-ffcee2a4612c","Optimal Trajectory Planning and Train Scheduling for Railway Systems","Wang, Y.","De Schutter, B. (promotor); Van den Boom, T.J.J. (promotor)","2014","Safe, fast, punctual, energy-efficient, and comfortable rail traffic systems are important for rail operators, passengers, and the environment. Due to the increasing energy prices and environmental concerns, the reduction of energy consumption has become one of the key objectives for railway systems. On the other hand, with the increase of passenger demands in urban rail transit systems of large cities, it is important to transport passengers safely and efficiently. The main focus of the research presented in this thesis is to determine and develop mathematical models and solution approaches to shorten the travel time of passengers and to reduce energy consumption in railway systems. More specifically, the travel time of passengers has been considered in train scheduling, where passenger demands of urban rail transit systems are included. The energy efficiency has been taken into account both in the train scheduling and in the operation of trains. The main topics investigated in the thesis can be summarized as: Optimal trajectory planning for a single train. We have considered the optimal trajectory planning problem for a single train under various operational constraints, which include the varying line resistance, variable speed restrictions, and the varying maximum traction force. The objective function of the optimization problem is a trade-off between the energy consumption and the riding comfort. We have proposed two approaches to solve this optimal control problem, namely a mixed-integer linear programming (MILP) approach and the pseudospectral method. Simulation results comparing the MILP approach, the pseudospectral method, and a discrete dynamic programming approach have shown that the pseudospectralmethod results in the best control performance, but that if the required computation time is also take into consideration, the MILP approach yields the best overall performance. Optimal trajectory planning for multiple trains. The optimal trajectory planning problem for multiple trains under fixed block signaling systems and moving block signaling systems has been investigated. Four solution approaches have been proposed: the greedy MILP approach, the simultaneous MILP approach, the greedy pseudospectral approach, the simultaneous pseudospectral method. Simulation results have shown that compared to the greedy approach, the simultaneous approach yields a better control performance but requires a higher computation time. In addition, the end time violations of the MILP approach are slightly larger than those of the pseudospectral method, but the computation time of the MILP approach is one to two orders of magnitude smaller than that of the pseudospectral method. Train scheduling for a single line based on OD-independent passenger demands. The train scheduling problem for an urban rail transit line has been considered with the aim of minimizing the total travel time of passengers and the energy consumption of the operation of trains. The departure times, running times, and dwell times of the trains have been optimized based on origin-destination-independent (OD-independent) passenger demands. We have proposed a new iterative convex programming (ICP) approach to solve this train scheduling problem. The performance of the ICP approach has been comparedwith other alternative approaches, such as nonlinear programming approaches, a mixed integer nonlinear programming (MINLP) approach, and an MILP approach. The ICP approach has been shown, via a case study, to provide the best trade-off between performance and computational complexity for the train scheduling problem. Train scheduling for a single line based on OD-dependent passenger demands. We have adopted a stop-skipping strategy to reduce the passenger travel time and the energy consumption further based on origin-destination dependent (OD-dependent) passenger demands in an urban rail transit line. The train scheduling problem with stop-skipping results in a mixed integer nonlinear programming problem and we have proposed a bi-level optimization approach and an efficient bi-level optimization approach to solve this problem. Simulation results show that the stop-skipping strategy outperforms the all-stop strategy. Moreover, the bi-level approach yields a better control performance than the efficient bi-level approach but at a cost of a higher computation time. Train scheduling for networks with time-varying OD-dependent passenger demands. For the train scheduling for urban rail transit networks, we have developed an event-driven model, where the time varying OD-dependent passenger demands, the splitting of passenger flows, and the passenger transfer behavior at transfer stations is included. The resulting train scheduling problem is a real-valued nonlinear nonconvex problem, which can be solved by gradient-free nonlinear programming approaches (e.g., pattern search), gradient-based nonlinear programming approaches (e.g., sequential quadratic programming (SQP)), genetic algorithms, or an MILP approach. We have applied an SQP method and a genetic algorithm to solve the train scheduling problem for a case study, the results of which have shown that the SQP method provides a better trade-off between control performance and computational complexity with respect to the genetic algorithm.","trajectory planning; train scheduling; passenger demand; urban rail transit; optimization","en","doctoral thesis","","","","","","","","","Mechanical, Maritime and Materials Engineering","Delft Center for Systems and Control","","","",""
"uuid:fdaf39e5-9af2-4f5d-860f-6aedb320de21","http://resolver.tudelft.nl/uuid:fdaf39e5-9af2-4f5d-860f-6aedb320de21","Generic Model Predictive Control Framework for Advanced Driver Assistance Systems","Wang, M.","Hoogendoorn, S.P. (promotor); Van Arem, B. (promotor)","2014","This thesis deals with a model predictive control framework for control design of Advanced Driver Assistance Systems, where car-following tasks are under control. The framework is applied to design several autonomous and cooperative controllers and to examine the controller properties at the microscopic level and the resulting traffic flow characteristics at the macroscopic level. The results give new insights into impacts of ADAS on traffic flow characteristics.","model predictive control; traffic flow theory; car-following; cooperative driving; Advanced Driver Assistance Systems","en","doctoral thesis","TRAIL","","","","","","","","Civil Engineering and Geosciences","Transport & Planning","","","",""
"uuid:06abf5c2-f5f4-4d32-a941-0e015bf03d8b","http://resolver.tudelft.nl/uuid:06abf5c2-f5f4-4d32-a941-0e015bf03d8b","Metagenomic insights into the bio-functionality of 21 anaerobic biogas reactors (abstract)","Tao, Y.; Gao, D.W.; Wang, H.Y.; Zhang, X.; Ghasimi, S.M.D.; Ozgun, H.; Ersahin, M.E.; Zhou, Z.B.; Liu, G.; Temudo, M.F.; Kloek, J.; Spanjers, H.; De Kreuk, M.K.; Van Lier, J.B.","","2014","","","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Water Management","","","",""
"uuid:ed22658a-24fe-49fd-83e9-cb6240747308","http://resolver.tudelft.nl/uuid:ed22658a-24fe-49fd-83e9-cb6240747308","MAX-DOAS observations of aerosols, formaldehyde and nitrogen dioxide in the Beijing area: Comparison of two profile retrieval approaches","Vlemmix, T.; Hendrick, F.; Pinardi, G.; De Smedt, I.; Fayt, C.; Hermans, C.; Piters, A.; Wang, P.; Levelt, P.F.; Van Roozendael, M.","","2014","A four year data set of MAX-DOAS observations in the Beijing area (2008–2012) is analysed with a focus on NO2, HCHO, and aerosols. Two very different retrieval methods are applied. Method A describes the tropospheric profile with 13 layers and makes use of the optimal estimation method. Method B uses 2–4 parameters to describe the tropospheric profile and an inversion based on a least-squares fit. For each constituent (NO2, HCHO and aerosols) the retrieval outcomes are compared in terms of tropospheric columns, surface concentrations, and ""characteristic profile heights"" (i.e. the height below which 75% of the vertically integrated tropospheric column resides). We find best agreement between the two methods for tropospheric NO2 columns, with a standard deviation of relative differences below 10%, a correlation of 0.99 and a linear regression with a slope of 1.03. For tropospheric HCHO columns we find a similar slope, but also a systematic bias of almost 10% which is likely related to differences in profile height. Aerosol optical depths (AODs) retrieved with method B are 20% high compared to method A. They are more in agreement with AERONET measurements, which are on average only 5% lower, however with considerable relative differences (standard deviation ~25%). With respect to near surface volume mixing ratios and aerosol extinction we find considerably larger relative differences: 10 ± 30%, ?23 ± 28% and ?8 ± 33% for aerosols, HCHO and NO2 respectively. The frequency distributions of these near-surface concentrations show however a quite good agreement, and this indicates that near-surface concentrations derived from MAX-DOAS are certainly useful in a climatological sense. A major difference between the two methods is the dynamic range of retrieved characteristic profile heights which is larger for method B than for method A. This effect is most pronounced for HCHO, where retrieved profile shapes with method A are very close to the a priori, and moderate for NO2 and aerosols which on average show quite good agreement for characteristic profile heights below 1.5 km. One of the main advantages of method A is the stability, even under suboptimal conditions (e.g., in the presence of clouds). Method B is generally more unstable and this explains probably a substantial part of the quite large relative differences between the two methods. However, despite a relatively low precision for individual profile retrievals it appears as if seasonally averaged profile heights retrieved with method B are less biased towards a priori assumptions than those retrieved with method A. This gives confidence in the result obtained with method B, namely that aerosol profiles tend on average to be higher than NO2 profiles in spring and summer, whereas they seem on average to be of the same height in winter, a result which is especially relevant in relation to the validation of satellite retrievals.","","en","journal article","European Geosciences Union (EGU)","","","","","","","","Civil Engineering and Geosciences","Geoscience & Remote Sensing","","","",""
"uuid:f18a4023-8b46-43ae-8c7c-31776750dced","http://resolver.tudelft.nl/uuid:f18a4023-8b46-43ae-8c7c-31776750dced","Adaptive Algebraic Multiscale Solver for Compressible Flow in Heterogeneous Porous Media","Tene, M.; Hajibeygi, H.; Wang, Y.; Tchelepi, H.A.","","2014","An adaptive Algebraic Multiscale Solver for Compressible (C-AMS) flow in heterogeneous oil reservoirs is developed. Based on the recently developed AMS [Wang et al., 2014] for incompressible linear flows, the C-AMS extends the algebraic formulation of the multiscale methods for compressible (nonlinear) flows. Several types of basis functions (incompressible and compressible with and without accumulation) are considered to construct the prolongation operator. As for the restriction operator, C-AMS allows for both MSFV and MSFE methods. Furthermore, to resolve high-frequency errors, Correction Functions and ILU(0) are considered. The best C-AMS procedure is determined among these various strategies, on the basis of the CPU time for three-dimensional heterogeneous problems. The C-AMS is adaptive in all aspects of prolongation, restriction, and conservative reconstruction operators for time-dependent compressible flow problems. In addition, it is also adaptive in terms of linear-system update. Though the C-AMS is a conservative multiscale solver (i.e., only a few iterations are employed infrequently in order to maintain high-quality results), a benchmark study is performed to investigate its efficiency against an industrial-grade Algebraic Multigrid (AMG) solver, SAMG [Stuben, 2010]. This comparative study illustrates that the C-AMS is quite efficient for compressible flow simulations in large-scale heterogeneous 3D reservoirs.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""
"uuid:889c0c65-e556-44c8-9496-efdaaad348f1","http://resolver.tudelft.nl/uuid:889c0c65-e556-44c8-9496-efdaaad348f1","Monotone Multiscale Finite Volume Method for Flow in Heterogeneous Porous Media","Wang, Y.; Hajibeygi, H.; Tchelepi, H.A.","","2014","The MultiScale Finite-Volume (MSFV) method is known to produce non-monotone solutions. The causes of the non-monotone solutions are identified and connected to the local flux across the boundaries of primal coarse cells induced by the basis functions. We propose a monotone MSFV (m-MSFV) method based on a local stencil-fix that guarantees monotonicity of the coarse-scale operator, and thus the resulting approximate fine-scale solution. Detection of non-physical transmissibility coefficients that lead to non-monotone solutions is achieved using local information only and is performed algebraically. For these 'critical' primal coarse-grid interfaces, a monotone local flux approximation, specifically, a Two- Point Flux Approximation (TPFA), is employed. Alternatively, a local linear boundary condition is used for the basis functions to reduce the degree of non-monotonicity. The local nature of the two strategies allows for ensuring monotonicity in local sub-regions, where the non-physical transmissibility occurs. For practical applications, an adaptive approach based on normalized positive off-diagonal coarse-scale transmissibility coefficients is developed. Based on the histogram of these normalized coefficients, one can remove the large peaks by applying the proposed modifications only for a small fraction of the primal coarse grids. Though the m-MSFV approach can guarantee monotonicity of the solutions to any desired level, numerical results illustrate that employing the m-MSFV modifications only for a small fraction of the domain can significantly reduce the non-monotonicity of the conservative MSFV solutions.","","en","conference paper","EAGE","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""
"uuid:7194c54c-a74f-4f90-ae30-215c6a06dae5","http://resolver.tudelft.nl/uuid:7194c54c-a74f-4f90-ae30-215c6a06dae5","High resolution radar rainfall for urban pluvial flood managementmanagement: Lessons learnt from 10 pilots in North-West Europe within the RainGain project","Ten Veldhuis, J.A.E.; Ochoa-Rodriguez, S.; Bruni, G.; Gires, A.; Van Assel, J.; Ichaba, A.; Kroll, S.; Wang, L.P.; Tchiguirinskaia, I.; Giangola Murzyn, A.; Richard, J.; Schertzer, D.; Willems, P.","","2014","Precipitation and catchment information needs to be available at high resolution to reliably predict hydrological response and potential flooding in urban catchments. While recent advances have been made in weather radar technology and availability of DTM for urban flood modelling, the question is whether these are sufficient to provide reliable predictions for urban pluvial flood control. The RainGain project (EU-Interreg IVB NWE) brings together radar technologists and hydrologists to explore a variety of rainfall sensors, rainfall data processing techniques and hydrodynamic models for the purpose of fine-scale representation of urban hydrodynamic response. High resolution rainfall and hydrodynamic modelling techniques are implemented at 10 different pilot locations under real-life conditions. In this paper, the pilot locations, configurations of rainfall sensors (including X-Band and C-Band radars, rain gauges and disdrometers) and modelling approaches adopted within the RainGain project are introduced. Initial results are presented of hydrodynamic modelling using high resolution precipitation inputs from dual-polarisation X-band radar, followed by a discussion of differences in hydrodynamic response behaviour between the pilots.","radar rainfall; urban hydrology; urban flood modelling","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Water Management","","","",""
"uuid:98fc4df0-8397-435f-819a-a893731e3d82","http://resolver.tudelft.nl/uuid:98fc4df0-8397-435f-819a-a893731e3d82","Study of design parameters of flapping-wings","Wang, Q.; Goosen, J.F.L.; Van Keulen, F.","","2014","As one of the most important components of a flapping-wing micro air vehicle (FWMAV), the design of an energy-efficient flapping-wing has been a research interest recently. Research on insect flight from different perspectives has been carried out, mainly with regard to wing morphology, flapping kinematics, and unsteady aerodynamics. However, the link between the wing morphology and kinematics with passive pitching has been neglected in flapping-wing design. To address this, a model based on a quasi-steady aerodynamic model and the passive pitching motion was made. To simplify the model and make optimization more feasible, the wing is modeled as a stiff plate with uniform mass distribution and a torsional spring at the wing root. An optimization is conducted with the objective of minimizing power consumption for hovering flight using the six most influential wing morphological and kinematic parameters as design variables. The sensitivity of lift generation and power consumption to all the parameters is analyzed. Compared to traditional artificial wings with straight leading edges as pitching axis, wings with a part of wing area in front of the pitching axis and smaller aspect ratio are able to perform more energy-efficient hovering flights. Preliminary design suggestions regarding the selection of wing shape and kinematics for FWMAVs are given.","IMAV2014; MAV; flapping-wing","en","conference paper","","","","","","","","","","","","","",""
"uuid:e664092a-face-4111-88dd-f20921ff17d8","http://resolver.tudelft.nl/uuid:e664092a-face-4111-88dd-f20921ff17d8","A Computational Study on the Aerodynamics of a 90 mm Ducted Contra-Rotating Lift Fan","Wang, Y.; Chen, W.; Wang, H.; Li, R.","","2014","In this paper, a steady 3D numerical study has been conducted on a 90 mm counter rotating lift fan to investigate its aerodynamic performance. The effect of axial distance between the fans and rotor speed are studied. A low thrust generation has been revealed from the simulation results due to the unfavourable working condition for the upstream rotor. Subsequently, an inlet guide vane (IGV) is geometrically designed to cause a preswirl effect at the inlet. Results show that the pressure ratio and total thrust are significantly improved at 10% by the IGV with a little sacrificing in efficiency. Such work can be a guidance in the further design and optimization.","IMAV2014; MAV; contra-rotating lift fan; rotation Speed; axial Space; pre-swirl","en","conference paper","","","","","","","","","","","","","",""
"uuid:3f8eff68-c4e9-438d-b629-296464f60e97","http://resolver.tudelft.nl/uuid:3f8eff68-c4e9-438d-b629-296464f60e97","Study of design parameters of flapping-wings","Wang, Q.; Goosen, J.F.L.; Van Keulen, F.","","2014","As one of the most important components of a flapping-wing micro air vehicle (FWMAV), the design of an energy-efficient flapping-wing has been a research interest recently. Research on insect flight from different perspectives has been carried out, mainly with regard to wing morphology, flapping kinematics, and unsteady aerodynamics. However, the link between the wing morphology and kinematics with passive pitching has been neglected in flapping-wing design. To address this, a model based on a quasi-steady aerodynamic model and the passive pitching motion was made. To simplify the model and make optimization more feasible, the wing is modeled as a stiff plate with uniform mass distribution and a torsional spring at the wing root. An optimization is conducted with the objective of minimizing power consumption for hovering flight using the six most influential wing morphological and kinematic parameters as design variables. The sensitivity of lift generation and power consumption to all the parameters is analyzed. Compared to traditional artificial wings with straight leading edges as pitching axis, wings with a part of wing area in front of the pitching axis and smaller aspect ratio are able to perform more energy-efficient hovering flights. Preliminary design suggestions regarding the selection of wing shape and kinematics for FWMAVs are given.","Micro Air Vehicle; flapping-wings","en","conference paper","Delft University of Technology","","","","","","","","Mechanical, Maritime and Materials Engineering","Precision and Microsystems Engineering","","","",""
"uuid:05c10738-f00f-4973-bad7-38b324cbafdc","http://resolver.tudelft.nl/uuid:05c10738-f00f-4973-bad7-38b324cbafdc","Off-board Visual Odometry and Control of an Ultralight Quadrotor MAV","Li, K.; Huang, R.; Phang, S.K.; Lai, S.; Wang, F.; Tan, P.; Chen, B.M.; Lee, T.H.","","2014","In this paper, we propose an approach to autonomously control a quadrotor micro aerial vehicle (MAV). With take-off weight of 50 g and 8-min flight endurance, the MAV platform codenamed KayLion developed by the National University of Singapore (NUS) is able to perform autonomous flight with pre-planned path tracking. The vision-based autonomous control is realized with a light weight camera system and an ultrasonic range finder integrated to the MAV. An optical flow algorithm is adopted and processed on ground control station to provide position and velocity estimation of the MAV. A model-based position controller is implemented to realize autonomous flight.","IMAV2014; MAV; ultralight; quadrotors; micro aerial vehicles","en","conference paper","","","","","","","","","","","","","",""
"uuid:f17280e8-188c-42cb-9d57-a8239a46b93a","http://resolver.tudelft.nl/uuid:f17280e8-188c-42cb-9d57-a8239a46b93a","Buckling Analysis of Grid-Stiffened Composite Shells","Wang, D.; Abdalla, M.M.","","2014","There is a renewed interest in grid-stiffened composite structures; they are not only competitive with conventional stiffened constructions and sandwich shells in terms of weight but also enjoy superior damage tolerance properties. In this paper, both global and local structural instabilities are investigated for grid-stiffened composite panels using homogenization theory. Characteristic cell configurations with periodic boundary constraints are employed for orthogrid- and isogrid-stiffened shells in order to smear the stiffened panel into an equivalent unstiffened shell. Homogenized properties corresponding to classical lamination theory are obtained by matching the strain energy of the stiffened and equivalent cells. Global buckling analysis is carried out based on the homogenized shell properties. Bloch wave theory is adopted to calculate the local buckling load of grid-stiffened shells, where the interaction of adjacent cells is fully taken into account. Moreover, instead of considering skin buckling and stiffener crippling separately, as is commonly done, the skin and stiffeners are assembled together at the level of the characteristic cell. The critical instabilities can be captured whether they are related to the skin or stiffener or their interaction. The proposed combination of global/local models can also be used to predict the material failure of a structure. Numerical examples of orthogrid- and isogrid-stiffened isotropic panels show that the local buckling loads predicted by the proposed method match finite element calculations better than semi-analytical methods based on assumptions and idealisations. The proposed method is further validated using typical configurations of flat composite panels and circular composite cylinders.","buckling; grid-stiffened structures; composite; homogenization techniques; Bloch wave theory","en","conference paper","CIMNE","","","","","","","","Aerospace Engineering","Aerospace Structures & Materials","","","",""
"uuid:85664bfc-6ceb-4136-b0cf-9ddff0e070c7","http://resolver.tudelft.nl/uuid:85664bfc-6ceb-4136-b0cf-9ddff0e070c7","Polymersomes as a potential tool in nuclear medicine","Wang, G.","Wolterbeek, H.Th. (promotor); Denkova, A. (promotor); Mendes, E. (promotor)","2014","Amphiphilic di-block copolymers composed of poly(ethylene oxide-b-butadiene), abbreviated PEO-PB can self-assemble into polymer vesicles (polymersomes) when placed in aqueous solution, provided that the ratio of hydrophilic block to the total molecular mass is between 25 % and 45 %. These vesicles consist of an aqueous cavity surrounded by a double-layered hydrophobic membrane constituted of poly-butadiene and it remains soluble due to the hydrophilic PEO brush that coats the inner and outer surface of the assembly. The major goal of this thesis is to design polymersomes for nuclear medical applications, in particular for alpha radionuclide therapy and to investigate their properties as potential nano-carriers. In this thesis, the first steps towards the application of polymersomes in nuclear medicine have been taken. The results clearly show the great potential of these carriers, i.e., high loading efficiency and no loss, but they also reveal that the pharmacokinetics of the polymersomes need to be improved and that different nano-vesicle design will be needed to increase recoil retention.","polymersomes; recoil retention; In vivo; Cross-linking; radiolabeling","en","doctoral thesis","","","","","","","","2015-07-02","Applied Sciences","Radiation, Radionuclides & Reactors","","","",""
"uuid:604f12ff-06af-41ad-935f-8789e36350e1","http://resolver.tudelft.nl/uuid:604f12ff-06af-41ad-935f-8789e36350e1","Modeling of parasitic elements in high voltage multiplier modules","Wang, J.","Ferreira, J.A. (promotor)","2014","It is an inevitable trend that the power conversion module will have higher switching frequency and smaller volume in the future. Bandgap devices, such as SiC and GaN devices, accelerate the process. With this process, the parasitic elements in the module will probably have stronger influence on circuit operations than before. In this thesis, modeling of parasitic elements in the HV multiplier module of the HV generator in medical X-ray machines is addressed. The modeling is studied in two cases, the steady and transient operation of the circuit. The study results in a thorough understanding of the parasitic elements at a modular level and their influences on the circuit operation. In addition, the approaches to the modeling of the parasitics contained in this thesis can also be applied in other power electronic modules those have high power density by utilizing new devices in the future. Parasitic capacitances in the multiplier module in the steady state: The HV multiplier module in a CT scanner, which is typically a symmetrical C.W. multiplier module, can have an output as high as 160kV. This results in large number of diodes and capacitors in a compact module. By utilizing SiC diodes, the volume of the module will become much smaller than before, and the switching frequency of the circuit will become higher. The structural parasitic capacitances in such a module can be significant to the steady circuit operation. However, they were never studied before. In this thesis, the parasitic capacitances in the multiplier are thoroughly studied at a modular level. The study follows a systematic approach, including definition of the role of the capacitances, extraction of the capacitances by 3D FE simulation, construction of the analytical model, analysis and validation of the model and minimization of the parasitic capacitances. With the complete analysis, the structural parasitic capacitances in the HV module are well known and minimized. The obtained knowledge can also be applied to different HV multiplier modules. Electric field in the multiplier module in the steady state: Apart from the influence of the parasitic capacitances, the HV multiplier module has another important issue --- insulation. The strong electric field induced by the high voltage should be well contained to avoid breakdown of the insulation oil. In this thesis, a simple shielding technique is introduced for use in the field reduction. The distribution of the electric field strength is analyzed based on the results obtained through 3D FE field simulation. The distribution can be expressed as a function containing parasitic capacitances. Then, a shielding technique is proposed to reduce the field based on the expression. Simulation results show that the shielding technique can well contain the strong electric field. Parasitics in the multiplier module in the fast transient period: Over time, X-ray tubes have a tendency to arc-over. This results in short-circuiting of the load of the HV generator and in turn fast transient current pulses in the circuit. The bandwidths of such pulses can enter upper MHz range. In such a system, high-order circuit model of the parasitic elements are required for accurate circuit analysis. In this thesis, a theoretical development is presented on the circuit modeling of an electrical component or system in the beginning of the intermediate frequency range, which is just above the quasi-static range. The power series approach is utilized to obtain the LME model of the parasitics. With this approach, the underlying reason why the kth-order circuit model is valid for a structure with given electrical size is well understood. The calculation of EM fields and the derivation of the LME model is mathematically simpler than that by the full wave approach. Besides, the extension of the power series approach to the continuous spectrum systems provides an extension from sinusoildally single frequency systems towards real cases involving pulsed quantities. The theory can be developed in the future and applied to various applications in which high-order circuit model is necessary.","high voltage multiplier; parasitic elements; electromagnetic field analysis; transient analysis; DC/DC converter; SiC","en","doctoral thesis","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Electrical Power Engineering","","","",""
"uuid:39e04e47-25a6-457e-a90b-972cecd12a77","http://resolver.tudelft.nl/uuid:39e04e47-25a6-457e-a90b-972cecd12a77","Tunable Luminescence of CeAl11O18 Based Phosphors by Replacement of (AlO)+ by (SiN)+ and Co-Doping with Eu","Yin, L.J.; Chen, G.Z; Wang, C.; Xu, X.; Hao, L.Y.; Hintzen, H.T.J.M.","","2014","A series of Si-N or Eu-Li doped CeAl11O18 and CeAl12O18N phosphors are prepared by solid–state reaction. Their structure and luminescence are researched carefully. Si-N doping with the concentration less than 8% can be successfully dissolved into CeAl11O18 crystal lattice and doesn't change the matrix structure, only resulting in crystal lattice shrinkage due to the shorter bond length for Si–N bond versus Al–O bond. It is observed that blue emission gradually decreases and UV emission becomes stronger due to the gradual disappearance of OMe ions with the increase of Si-N doping. Compared with the traditional UV emitting phosphor CeMgAl11O19, Si-N doped CeAl11O18 shows better thermal stability. The crystal structure and lattice parameters of Eu-Li codoped CeAl11O18 remain unchanged due to the large tolerance of rare-earth sites. On account of the energy transfer from UV emission of Ce3+ to Eu2+, a single overlapping blue emission with high intensity is obtained in Eu-Li codoped CeAl11O18 phosphor.","","en","journal article","The Electrochemical Society","","","","","","","","Applied Sciences","RST/Radiation, Science and Technology","","","",""
"uuid:fae9782b-6ae5-436f-b51f-a002f0a496b2","http://resolver.tudelft.nl/uuid:fae9782b-6ae5-436f-b51f-a002f0a496b2","Algebraic Connectivity of Interdependent Networks","Martin-Hernandez, J.; Wang, H.; Van Mieghem, P.; D'Agostino, G.","","2014","The algebraic connectivity UN-1, i.e. the second smallest eigenvalue of the Laplacian matrix, plays a crucial role in dynamic phenomena such as diffusion processes, synchronization stability, and network robustness. In this work we study the algebraic connectivity in the general context of interdependent networks, or network-of-networks (NoN). The present work shows, both analytically and numerically, how the algebraic connectivity of NoNs experiences a transition. The transition is characterized by a saturation of the algebraic connectivity upon the addition of suffcient coupling links (between the two individual networks of a NoN). In practical terms, this shows that NoN topologies require only a fraction of coupling links in order to achieve optimal diffusivity. Furthermore, we observe a footprint of the transition on the properties of Fiedler's spectral bisection.","Network of Networks; Synchronization; Laplacian; Spectral Properties; System of Systems","en","journal article","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Network Architectures & Services (NAS)","","","",""
"uuid:5b9c836b-31a7-4932-a2ef-2a2793499ed0","http://resolver.tudelft.nl/uuid:5b9c836b-31a7-4932-a2ef-2a2793499ed0","EMG patterns during assisted walking in the exoskeleton","Sylos-Labini, F.; La Scaleia, V.; d'Avella, A.; Pisotta, I.; Tamburella, F.; Scivoletto, G.; Molinari, M.; Wang, S.; Wang, L.; Van Asseldonk, E.; Van der Kooij, H.; Hoellinger, T.; Cheron, G.; Thorsteinsson, F.; Ilzkovitz, M.; Gancet, J.; Hauffe, R.; Zanov, F.; Lacquaniti, F.; Ivanenko, Y.P.","","2014","Neuroprosthetic technology and robotic exoskeletons are being developed to facilitate stepping, reduce muscle efforts, and promote motor recovery. Nevertheless, the guidance forces of an exoskeleton may influence the sensory inputs, sensorimotor interactions and resulting muscle activity patterns during stepping. The aim of this study was to report the muscle activation patterns in a sample of intact and injured subjects while walking with a robotic exoskeleton and, in particular, to quantify the level of muscle activity during assisted gait. We recorded electromyographic (EMG) activity of different leg and arm muscles during overground walking in an exoskeleton in six healthy individuals and four spinal cord injury (SCI) participants. In SCI patients, EMG activity of the upper limb muscles was augmented while activation of leg muscles was typically small. Contrary to our expectations, however, in neurologically intact subjects, EMG activity of leg muscles was similar or even larger during exoskeleton-assisted walking compared to normal overground walking. In addition, significant variations in the EMG waveforms were found across different walking conditions. The most variable pattern was observed in the hamstring muscles. Overall, the results are consistent with a non-linear reorganization of the locomotor output when using the robotic stepping devices. The findings may contribute to our understanding of human-machine interactions and adaptation of locomotor activity patterns.","robotic exoskeleton; assisted gait; EMG patterns; spinal cord injury; neuroprosthetic technology","en","journal article","Frontiers","","","","","","","","Mechanical, Maritime and Materials Engineering","Biomechanical Engineering","","","",""
"uuid:bcc282ec-5501-4988-8d18-a7ab74895d2b","http://resolver.tudelft.nl/uuid:bcc282ec-5501-4988-8d18-a7ab74895d2b","Evaluation of broadband surface solar irradiance derived from the Ozone Monitoring Instrument","Wang, P.; Sneep, M.; Veefkind, J.P.; Stammes, P.; Levelt, P.F.","","2014","Surface solar irradiance (SSI) data are important for planning and estimating the production of solar power plants. Long-term high quality surface solar radiation data are needed for monitoring climate change. This paper presents a new surface solar irradiance dataset, the broadband (0.2–4 ?m) surface solar irradiance product derived from the Ozone Monitoring Instrument (OMI). The OMI SSI algorithm is based on the Heliosat method and uses the OMI O2–O2 cloud product as main input. The OMI SSI data are validated against the globally distributed Baseline Surface Radiation Network (BSRN) measurements at 19 stations for the year 2008. Furthermore, the monthly mean OMI SSI data are compared to independent surface solar irradiance products from International Satellite Cloud Climatology Project Flux Data (ISCCP-FD) and Clouds and the Earth's Radiant Energy System (CERES) data for the year 2005. The mean difference between OMI SSI and BSRN global (direct + diffuse) irradiances is ? 1.2 W m? 2 (? 0.2%), the root mean square error is 100.1 W m? 2 (18.1%), and the mean absolute error is 67.8 W m? 2 (12.2%). The differences between OMI SSI and BSRN global irradiances are smaller over continental and coastal sites and larger over deserts and islands. OMI SSI has a good agreement with the CERES shortwave (SW) model B surface downward flux (SDF) product. The correlation coefficient and index of agreement between monthly mean 1-degree gridded OMI SSI and CERES SW SDF are > 0.99. OMI SSI is lower than CERES SW SDF which is partly due to the solar zenith angle. On average, OMI SSI is 13.5 W m? 2 (2.5%) lower than the ISCCP-FD SW surface downward flux and the correlation coefficient and index of agreement are > 0.98 for every month.","broadband surface solar irradiance; ozone Monitoring Instrument (OMI); validation; baseline Surface Radiation Network (BSRN); CERES shortwave flux; ISCCP radiation product; OMI effective cloud fraction","en","journal article","Elsevier","","","","","","","","Civil Engineering and Geosciences","Geoscience & Remote Sensing","","","",""
"uuid:035d836d-19b1-4340-8042-160c58426e19","http://resolver.tudelft.nl/uuid:035d836d-19b1-4340-8042-160c58426e19","Geometric road runoff estimation from laser mobile mapping data","Wang, J. (TU Delft Optical and Laser Remote Sensing; Key Laboratory of quantitative Remote Sensing Information Technology; Chinese Academy of Sciences); González-Jorge, Higinio (University of Vigo); Lindenbergh, R.C. (TU Delft Optical and Laser Remote Sensing); Arias-Sánchez, Pedro (University of Vigo); Menenti, M. (TU Delft Optical and Laser Remote Sensing)","","2014","Mountain roads are the lifelines of remote areas but are often situated in complicated settings and prone to landslides, rock fall, avalanches and damages due to surface water runoff. The impact and likelihood of these types of hazards can be partly assessed by a detailed geometric analysis of the road environment. Field measurements in remote areas are expensive however. A possible solution is the use of a Laser Mobile Mapping System (LMMS) which, at high measuring rate, captures dense and accurate point clouds. This paper presents an automatic approach for the delineation of both the direct environment of a road and the road itself into local catchments starting from a LMMS point cloud. The results enable a user to assess where on the road most water from the surroundings will assemble, and how water will flow over the road after e.g. heavy snow melt or rainfall. To arrive at these results the following steps are performed. First outliers are removed and point cloud data is gridded at a uniform width. Local surface normal and gradient of each grid point are determined. The relative smoothness of the road is used as a criterion to identify the road's outlines. The local gradients are input for running the so-called D8 method, which simply exploits that surface water follows the direction of steepest descent. This method first enables the identification of sinks on the roadside, i.e. the locations where water flow accumulates and potentially enters the road. Moreover, the method divides the road's direct neighbourhood into catchments, each consisting of all grid cells having runoff to the same sink. In addition the method is used to analyse the surface flow over the road's surface. The new method is demonstrated on a piece of 153 meters long Galician mountain road as sampled by LMMS data.","Catchments; D8 algorithm; Mobile Laser Scanning; Point Cloud Data; Road Engineering; Road runoff","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:7ee45a22-ad73-4cf8-8b7a-2fefdcdbfcf2","http://resolver.tudelft.nl/uuid:7ee45a22-ad73-4cf8-8b7a-2fefdcdbfcf2","Characterization of the RnfB and RnfG Subunits of the Rnf Complex from the Archaeon Methanosarcina acetivorans","Suharti, S.; Wang, M.; De Vries, S.; Ferry, J.G.","","2014","Rnf complexes are redox-driven ion pumps identified in diverse species from the domains Bacteria and Archaea, biochemical characterizations of which are reported for two species from the domain Bacteria. Here, we present characterizations of the redox-active subunits RnfG and RnfB from the Rnf complex of Methanosarcina acetivorans, an acetate-utilizing methane-producing species from the domain Archaea. The purified RnfG subunit produced in Escherichia coli fluoresced in SDS-PAGE gels under UV illumination and showed a UV-visible spectrum typical of flavoproteins. The Thr166Gly variant of RnfG was colorless and failed to fluoresce under UV illumination confirming a role for Thr166 in binding FMN. Redox titration of holo-RnfG revealed a midpoint potential of ?129 mV for FMN with n = 2. The overproduced RnfG was primarily localized to the membrane of E. coli and the sequence contained a transmembrane helix. A topological analysis combining reporter protein fusion and computer predictions indicated that the C-terminal domain containing FMN is located on the outer aspect of the cytoplasmic membrane. The purified RnfB subunit produced in E. coli showed a UV-visible spectrum typical of iron-sulfur proteins. The EPR spectra of reduced RnfB featured a broad spectral shape with g values (2.06, 1.94, 1.90, 1.88) characteristic of magnetically coupled 3Fe-4S and 4Fe-4S clusters in close agreement with the iron and acid-labile sulfur content. The ferredoxin specific to the aceticlastic pathway served as an electron donor to RnfB suggesting this subunit is the entry point of electrons to the Rnf complex. The results advance an understanding of the organization and biochemical properties of the Rnf complex and lay a foundation for further understanding the overall mechanism in the pathway of methane formation from acetate.","","en","journal article","Public Library of Science","","","","","","","","Applied Sciences","BT/Biotechnology","","","",""
"uuid:e80ea693-8b8a-4948-8336-3964e32d9fe5","http://resolver.tudelft.nl/uuid:e80ea693-8b8a-4948-8336-3964e32d9fe5","Weather radar for urban hydrological applications: Lessons learnt and research needs identified from 4 pilot catchments in North-West Europe","Ten Veldhuis, J.A.E.; Ochoa-Rodriguez, S.; Bruni, G.; Gires, A.; Van Assel, J.; Wang, L.; Reinoso Rodinel, R.; Kroll, S.; Schertzer, D.; Onof, C.; Willems, P.","","2014","This study investigates the impact of rainfall estimates of different spatial resolutions on the hydraulic outputs of the models of four of the EU RainGain project’s pilot locations (the Cranbrook catchment (UK), the Herent catchment (Belgium), the Morée-Sausset catchment (France) and the Kralingen District (The Netherlands)). Two storm events, one convective and one stratiform, measured by a polarimetric X-band radar located in Cabauw (The Netherlands) were selected for analysis. The original radar estimates, at 100 m and 1 min resolutions, were aggregated to a spatial resolution of 1000 m. These estimates were then applied to the high-resolution semi-distributed hydraulic models of the four urban catchments, all of which have similar size (between 5 and 8 km2), but different morphological, hydrological and hydraulic characteristics. When doing so, methodologies for standardising rainfall inputs and making results comparable were implemented. The response of the different catchments to rainfall inputs of varying spatial resolution is analysed in the light of model configuration, catchment and storm characteristics. Rather surprisingly, the results show that for the two events under consideration the spatial resolution (i.e.100 m vs 1000 m) of rainfall inputs does not have a significant influence on the outputs of urban drainage models. The present study will soon be extended to more storms as well as model structures and resolutions, with the final aim of identifying critical spatial-temporal resolutions for urban catchment modelling in relation to catchment and storm event characteristics","","en","conference paper","ACSE","","","","","","","","Civil Engineering and Geosciences","Water Management","","","",""
"uuid:7a605793-b09e-439a-ac11-a03690d241ab","http://resolver.tudelft.nl/uuid:7a605793-b09e-439a-ac11-a03690d241ab","Relative role of bed roughness change and bed erosion on peak discharge increase in hyperconcentrated floods","Li, W.; Wang, Z.B.; Van Maren, D.S.; De Vriend, H.J.; Wu, B.S.","","2014","River floods are usually featured by a downstream flattening discharge peak whereas a downstream increasing discharge peak is observed at a rate exceeding the tributary discharge during highly silt-laden floods (hyperconcentrated floods) in China’s Yellow River. It entails a great challenge in the downstream flood defence and the underlying mechanisms need to be unravelled. Previous study on this issue only focuses on one possible mechanism, while the present work aims to reveal the relative importance of bed roughness change and bed erosion in the hyperconcentrated flood. Using a newly developed fully coupled morphodynamic model, we have conducted a numerical study for the 2004 hyperconcentrated flood in the Xiaolangdi-Jiahetan reach of the Lower Yellow River. In order to focus on the physical mechanism and to reduce uncertainty from low-resolution topography data, the numerical modeling was carried out in a schematized 1-D channel of constant width. The basic understanding that bed roughness decreases with concentration at moderate concentrations (e.g. several 10 s to 100 s g L?1) was incorporated by a simple power-law relation between Manning roughness coefficient and sediment concentration. The feedback between the bed deformation and the turbid flow, however, was fully accounted for, in the constituting equations as well as in the numerical solutions. The model successfully reproduced the downstream flood peak increase for the 2004 flood when considering the hyperconcentration-induced bed roughness reduction. As the hyperconcentration lags shortly behind the flood peak, later parts of the flood wave may experience less friction and overtake the wave front, leading to the discharge increase. In comparison, bed erosion is much less important to the discharge increase, at least for hyperconcentrated flood of moderate sediment concentration.","","en","journal article","European Geosciences Union","","","","","","","","Civil Engineering and Geosciences","Water Management","","","",""
"uuid:3b4e41eb-2b45-4648-82c6-a5d899dce6d3","http://resolver.tudelft.nl/uuid:3b4e41eb-2b45-4648-82c6-a5d899dce6d3","Challenges in modelling river flow and ice regime on the Ningxia–Inner Mongolia reach of the Yellow River, China","Fu, C.; Popescu, I.; Wang, C.; Mynett, A.E.; Zhang, F.","","2014","During winter the Yellow River in China is frequently subjected to ice flood disasters. Possible dike breaking due to ice floods poses a serious threat to the part of the region located along the river, in particular the Ning–Meng reach (including Ningxia Hui and the Inner Mongolia autonomous regions). Due to its special geographical location and river flow direction, the ice dams and jams lead to dike breaking and overtopping on the embankment, which has resulted in huge casualties and property losses throughout history. Therefore, there is a growing need to develop capability in forecasting and analysing river ice floods. Research into ice floods along the river is taking place at the Yellow River Conservancy Commission (YRCC). A numerical model is one of the essential parts of the current research going on at the YRCC, which can be used to supplement the inadequacies in the field and lab studies which are being carried out to help understand the physical processes of river ice on the Yellow River. Based on the available data about the Ning–Meng reach of the Yellow River, the YRCC river ice dynamic model (YRIDM) has been tested for capabilities to conduct ice flood forecasting. The YRIDM can be applied to simulate water level, discharge, water temperature, and ice cover thickness under unsteady-state conditions. Different scenarios were designed to explore the model uncertainty for two bounds (5 and 95%) and probability distribution. The YRIDM is an unsteady-state flow model that can show the basic regular pattern of ice floods; hence it can be used as an important tool to support decision making. The recommendation is that data and research should be continued in order to support the model and to measure improvements.","","en","journal article","European Geosciences Union","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:64ebd20d-3633-4b00-8ee2-7cca4631c254","http://resolver.tudelft.nl/uuid:64ebd20d-3633-4b00-8ee2-7cca4631c254","Observations and analysis of phase scintillation of spacecraft signal on the interplanetary plasma","Molera Calvés, G.; Pogrebenko, S.V.; Cimò, G.; Duev, D.A.; Bocanegra-Bahamón, T.M.; Wagner, J.F.; Kallunki, J.; De Vicente, P.; Kronschnabl, G.; Haas, R.; Quick, J.; Maccaferri, G.; Colucci, G.; Wang, W.H.; Yang, W.J.; Hao, L.F.","","2014","Aims. The phase scintillation of the European Space Agency’s Venus Express (VEX) spacecraft telemetry signal was observed at X-band (? = 3.6 cm) with a number of radio telescopes of the European Very Long Baseline Interferometry (VLBI) Network in the period 2009–2013. Methods. We found a phase fluctuation spectrum along the Venus orbit with a nearly constant spectral index of ?2.42 ± 0.25 over the full range of solar elongation angles from 0° to 45°, which is consistent with Kolmogorov turbulence. Radio astronomical observations of spacecraft signals within the solar system give a unique opportunity to study the temporal behaviour of the signal’s phase fluctuations caused by its propagation through the interplanetary plasma and the Earth’s ionosphere. This gives complementary data to the classical interplanetary scintillation (IPS) study based on observations of the flux variability of distant natural radio sources. Results. We present here our technique and the results on IPS. We compare these with the total electron content for the line of sight through the solar wind. Finally, we evaluate the applicability of the presented technique to phase-referencing VLBI and Doppler observations of currently operational and prospective space missions.","scattering; plasmas; interplanetary medium; Sun: heliosphere; techniques: interferometric; astrometry","en","journal article","EDP Sciences","","","","","","","","Aerospace Engineering","Space Engineering","","","",""
"uuid:91404545-dc7b-48c8-b9b5-a37fbf74ce5c","http://resolver.tudelft.nl/uuid:91404545-dc7b-48c8-b9b5-a37fbf74ce5c","E-waste: Collect more, treat better; Tracking take-back system performance for eco-efficient electronics recycling","Wang, F.","Stevel, A.L.N. (promotor)","2014","This dissertation establishes a methodology for evaluating the performance of take-back and treatment systems for end-oflife electronics (e-waste). First, a comprehensive classification is developed to fully understand the complex characteristics of e-waste. A multivariate model is then created to quantify e-waste generation for mapping e-waste flows and tracking the collection efficiency. A multidisciplinary approach is taken to assess the technical performance of e-waste treatment infrastructures, as well as environmental, economic and social impacts associated with them. The results from the model development and case studies demonstrate that the constructed methodology is effective to identify working priorities and intervention measures for improving system performance. The research conducted represents up-to-date knowledge of both scientific research and implementation experience in the field of global e-waste management. The outcomes can be used to facilitate the progress of upgrading take-back and treatment systems to improve eco-efficiency, for more collection and better treatment in both developed and developing countries.","WEEE; E-waste; Waste Management; Take-back; Recycling","en","doctoral thesis","Design for Sustainability Program","","","","","","","2014-03-17","Industrial Design Engineering","Department of Design Engineering","","","",""
"uuid:f0e38597-a742-4e20-808d-93cc6726669b","http://resolver.tudelft.nl/uuid:f0e38597-a742-4e20-808d-93cc6726669b","Design and numerical investigation of swirl recovery vanes for the Fokker 29 propeller","Wang, Y.; Li, Q.; Eitelberg, G.; Veldhuis, L.L.M.; Kotsonis, M.","","2014","Swirl recovery vanes (SRVs) are a set of stationary vanes located downstream from a propeller, which may recover some of the residual swirl from the propeller, hoping for an improvement in both thrust and efficiency. The SRV concept design for a scaled version representing the Fokker 29 propeller is performed in this paper, which may give rise to a promotion in propulsive performance of this traditional propeller. Firstly the numerical strategy is validated from two aspects of global quantities and the local flow field of the propeller compared with experimental data, and then the exit flow together with the development of propeller wake is analyzed in detail. Three kinds of SRV are designed with multiple circular airfoils. The numerical results show that the swirl behind the propeller is recovered significantly with Model V3, which is characterized by the highest solidity along spanwise, for various working conditions, and the combination of rotor and vane produced 5.76% extra thrust at the design point. However, a lower efficiency is observed asking for a better vane design and the choice of a working point. The vane position is studied which shows that there is an optimum range for higher thrust and efficiency.","multiple circular airfoil; propellers; propulsion efficiency; swirl recovery vane; turboprop engine","en","journal article","Elsevier","","","","","","","","Aerospace Engineering","Aerodynamics, Wind Energy & Propulsion","","","",""
"uuid:c64a7580-8045-487e-9bce-982e41248d85","http://resolver.tudelft.nl/uuid:c64a7580-8045-487e-9bce-982e41248d85","Advancing catchment hydrology to deal with predictions under change","Ehret, U.; Gupta, H.V.; Sivapalan, M.; Weijs, S.V.; Schymanski, S.J.; Blöschl, G.; Gelfan, A.N.; Harman, C.; Kleidon, A.; Bogaard, T.A.; Wang, D.; Wagener, T.; Scherer, U.; Zehe, E.; Bierkens, M.F.P.; Di Baldassarre, G.; Parajka, J.; Van Beek, L.P.H.; Van Griensven, A.; Westhoff, M.C.; Winsemius, H.C.","","2014","Throughout its historical development, hydrology as an earth science, but especially as a problem-centred engineering discipline has largely relied (quite successfully) on the assumption of stationarity. This includes assuming time invariance of boundary conditions such as climate, system configurations such as land use, topography and morphology, and dynamics such as flow regimes and flood recurrence at different spatio-temporal aggregation scales. The justification for this assumption was often that when compared with the temporal, spatial, or topical extent of the questions posed to hydrology, such conditions could indeed be considered stationary, and therefore the neglect of certain long-term non-stationarities or feedback effects (even if they were known) would not introduce a large error.","","en","journal article","European Geosciences Union","","","","","","","","Civil Engineering and Geosciences","Water Management","","","",""
"uuid:a759c289-1f08-43a8-9b22-d9e2065f676b","http://resolver.tudelft.nl/uuid:a759c289-1f08-43a8-9b22-d9e2065f676b","Four years of ground-based MAX-DOAS observations of HONO and NO2 in the Beijing area","Hendrick, F.; Müller, J.F.; Clémer, K.; Wang, P.; De Maziere, M.; Fayt, C.; Gielen, C.; Hermans, C.; Ma, J.Z.; Pinardi, G.; Stavrakou, T.; Vlemmix, T.; Van Roozendael, M.","","2014","Ground-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements of nitrous acid (HONO) and its precursor NO2 (nitrogen dioxide) as well as aerosols have been performed daily in Beijing city centre (39.98° N, 116.38° E) from July 2008 to April 2009 and at the suburban site of Xianghe (39.75° N, 116.96° E) located ~60 km east of Beijing from March 2010 to December 2012. This extensive dataset allowed for the first time the investigation of the seasonal cycle of HONO as well as its diurnal variation in and in the vicinity of a megacity. Our study was focused on the HONO and NO2 near-surface concentrations (0–200 m layer) and total vertical column densities (VCDs) and also aerosol optical depths (AODs) and extinction coefficients retrieved by applying the Optimal Estimation Method to the MAX-DOAS observations. Monthly averaged HONO near-surface concentrations at local noon display a strong seasonal cycle with a maximum in late fall/winter (~0.8 and 0.7 ppb at Beijing and Xianghe, respectively) and a minimum in summer (~0.1 ppb at Beijing and 0.03 ppb at Xianghe). The seasonal cycles of HONO and NO2 appear to be highly correlated, with correlation coefficients in the 0.7–0.9 and 0.5–0.8 ranges at Beijing and Xianghe, respectively. The stronger correlation of HONO with NO2 and also with aerosols observed in Beijing suggests possibly larger role of NO2 conversion into HONO in the Beijing city center than at Xianghe. The observed diurnal cycle of HONO near-surface concentration shows a maximum in the early morning (about 1 ppb at both sites) likely resulting from night-time accumulation, followed by a decrease to values of about 0.1–0.4 ppb around local noon. The HONO / NO2 ratio shows a similar pattern with a maximum in the early morning (values up to 0.08) and a decrease to ~0.01–0.02 around local noon. The seasonal and diurnal cycles of the HONO near-surface concentration are found to be similar in shape and in relative amplitude to the corresponding cycles of the HONO total VCD and are therefore likely driven mainly by the balance between HONO sources and the photolytic sink, whereas dilution effects appear to play only a minor role. The estimation of OH radical production from HONO and O3 photolysis based on retrieved HONO near-surface concentrations and calculated photolysis rates indicate that in the 0–200 m altitude range, HONO is by far the largest source of OH radicals in winter as well as in the early morning at all seasons, while the contribution of O3 dominates in summer from mid-morning until mid-afternoon.","","en","journal article","European Geosciences Union","","","","","","","","Civil Engineering and Geosciences","Geoscience & Remote Sensing","","","",""
"uuid:5262ded8-6f93-4991-92c7-214d54381d89","http://resolver.tudelft.nl/uuid:5262ded8-6f93-4991-92c7-214d54381d89","Numerical study of VIV over a flexible riser","Fontaine, G.; Gross, D.; Lothode, C.; Guilmineau, E.; Wang, A.; Vertallier, F.; Minguez, M.; Cinello, A.","","2014","","hydrodynamics","","conference paper","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:acdbe89f-e0ed-4d47-963f-392f8b6e1975","http://resolver.tudelft.nl/uuid:acdbe89f-e0ed-4d47-963f-392f8b6e1975","Design of a steel pontoon-type semi-submersible floater supporting the DTU 10 MW reference turbine","Wang, Qiang","Lourens, E (mentor)","2014","","","","master thesis","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Offshore and Dredging Engineering","","",""
"uuid:bb2c5a9e-5e07-4eb0-ad55-a0465b0e7f0d","http://resolver.tudelft.nl/uuid:bb2c5a9e-5e07-4eb0-ad55-a0465b0e7f0d","Numerical study of transient harbor resonance induced by solitary waves","Gao, Junliang; Ma, Xiaozhou; Dong, Guohai; Wang, Gang; Ma, Yuxiang","","2014","","offshore","","journal article","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:da72174c-eadb-4514-a77d-2ca530e00c35","http://resolver.tudelft.nl/uuid:da72174c-eadb-4514-a77d-2ca530e00c35","Numerical study of the aerodynamics of a NACA 4412 airfoil in dynamic ground effect","Qu, Q.; Jia, X.; Wang, W.; Liu, P.; Agarwal, R.K.","","2014","","resistance & propulsion","","journal article","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:189bb4a8-1830-4eb0-8c53-335da76020a6","http://resolver.tudelft.nl/uuid:189bb4a8-1830-4eb0-8c53-335da76020a6","Numerical study on the water impact of 3D bodies by an explicit finite element method","Wang, Shan; Guedes Soares, C.","","2014","","hydrodynamics","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:33c55df5-d179-4ba7-b6dd-e6bdac7e4231","http://resolver.tudelft.nl/uuid:33c55df5-d179-4ba7-b6dd-e6bdac7e4231","Proceedings of the 11th International Conference on Hydrodynamics, ICHD 2014 (summary)","Tan, S.K.; Tan, S.K.; Wang, X.; Gho, W.M.; Joy, C.","","2014","","hydrodynamics","","conference paper","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Design, Production and Operation","","",""
"uuid:6eadca5b-77f2-43f4-9ebb-581869f37bfb","http://resolver.tudelft.nl/uuid:6eadca5b-77f2-43f4-9ebb-581869f37bfb","A two-time scale control law based on singular perturbations used in rudder roll stabilization of ships","Ren, Ru-Yi; Zou, Zao-Jian; Wang, Xue-Gang","","2014","","hydrodynamics","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:b965bce3-fd42-46f0-8810-1a89e969b748","http://resolver.tudelft.nl/uuid:b965bce3-fd42-46f0-8810-1a89e969b748","Stochastic hydroelastic analysis of a very large floating structure using pseudo-excitation method","Li, Hai-Tao; Wang, Qi-bin; Zong, Zhi; Sun, Lei; Liang, Hui","","2014","","hydrodynamics","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:f4ceba4f-fbd1-407a-82a8-c53d0352f73e","http://resolver.tudelft.nl/uuid:f4ceba4f-fbd1-407a-82a8-c53d0352f73e","Proceedings of the 11th International Conference on Hydrodynamics, ICHD 2014","Tan, S.K.; Tan, S.K.; Wang, X.; Gho, W.M.; Joy, C.","","2014","","hydrodynamics","","conference paper","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Design, Production and Operation","","",""
"uuid:381804e2-ca66-4fea-8bc9-918986c1a2a3","http://resolver.tudelft.nl/uuid:381804e2-ca66-4fea-8bc9-918986c1a2a3","Sensitivity analysis and parametric identification for ship manoeuvring in 4 degrees of freedom","Wang, X-G; Zou, Z-J.; Xu, F.; Ren, R.-Y.","","2014","","hydrodynamics","","journal article","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:880315b6-690d-4d07-8598-d589c319c2d5","http://resolver.tudelft.nl/uuid:880315b6-690d-4d07-8598-d589c319c2d5","DNSSEC Misconfigurations: How incorrectly configured security leads to unreachability","van Adrichem, N.L.M. (TU Delft Network Architectures and Services); Reyes Lua, A; Wang, X. (TU Delft Network Architectures and Services); Wasif, M; Fatturrahman, F; Kuipers, F.A. (TU Delft Network Architectures and Services)","Chen, H (editor)","2014","","","en","conference paper","IEEE Society","","","","","","","","","","Network Architectures and Services","","",""
"uuid:5c7cff90-73ea-48f1-a43e-650aaa4dd91b","http://resolver.tudelft.nl/uuid:5c7cff90-73ea-48f1-a43e-650aaa4dd91b","Epidemic threshold in directed networks","Li, C.; Wang, H.; Van Mieghem, P.F.A.","","2013","Epidemics have so far been mostly studied in undirected networks. However, many real-world networks, such as the online social network Twitter and the world wide web, on which information, emotion, or malware spreads, are directed networks, composed of both unidirectional links and bidirectional links. We define the directionality ? as the percentage of unidirectional links. The epidemic threshold ? c for the susceptible-infected-susceptible (SIS) epidemic is lower bounded by 1/? 1 in directed networks, where ? 1 , also called the spectral radius, is the largest eigenvalue of the adjacency matrix. In this work, we propose two algorithms to generate directed networks with a given directionality ? . The effect of ? on the spectral radius ? 1 , principal eigenvector x 1 , spectral gap (? 1 ?|? 2 |), and algebraic connectivity ? N?1 is studied. Important findings are that the spectral radius ? 1 decreases with the directionality ? , whereas the spectral gap and the algebraic connectivity increase with the directionality ? . The extent of the decrease of the spectral radius depends on both the degree distribution and the degree-degree correlation ? D. Hence, in directed networks, the epidemic threshold is larger and a random walk converges to its steady state faster than that in undirected networks with the same degree distribution.","","en","journal article","American Physical Society","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Intelligent Systems","","","",""
"uuid:36e87a9f-daca-4fc9-963e-d1c4519022e3","http://resolver.tudelft.nl/uuid:36e87a9f-daca-4fc9-963e-d1c4519022e3","On the Formation of Radial Tidal Current off the Central Jiangsu Coast","Yao, P.; Stive, M.J.F.; Zhang, C.; Su, M.; Wang, Z.B.","","2013","In the South Yellow Sea off the Jiangsu coast, there exists a special type of sand bodies, which are known as radial sand ridge field (RSRF). One of the characteristics of this area is the distinctive radial tidal current field. Although many studies have focused on the hydrodynamic environment around radial sand ridges, the knowledge on the genesis of the radial tidal current is still in a very basic stage. This paper attempts to explore the influence of the tidal dynamics in large Shelf Sea on the formation mechanism of the local tidal current pattern using a schematized process-based model. Different incoming tidal signals are applied in this model respectively to investigate the related current pattern in RSRF. The results reveal that the radial current field only exists under some specified tidal signals from open sea. Furthermore, the geometry of the basin also plays a significant role in the formation of the current pattern.","radial tidal current field; radial sand ridges; formation mechanism; tidal wave","en","conference paper","Tsinghua University Press","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:1005c5ae-d4f6-40c3-8f13-3062ac87ac70","http://resolver.tudelft.nl/uuid:1005c5ae-d4f6-40c3-8f13-3062ac87ac70","Further Research on the Tidal Wave System in the Southern Yellow Sea","Su, M.; Wang, Z.B.; Zhang, C.; Yao, P.; Stive, M.J.F.","","2013","A two-dimensional tidal wave model for the Chinese marginal seas with high resolution is set up and the verification results demonstrate that it can well simulate the large domain. Based on this model, a series of numerical experiments are constructed to analyze the influence of local bathymetry and reclamation of the Jiangsu coast on the tidal wave system. According to the simulation results, the existence of the radial tidal current pattern have not been obviously influenced by the local bathymetry except the magnitude of the current velocity. However, it effects the tidal wave near the Jiangsu coast considerably. The reclamation affects the radial current field slightly, whereas the tidal wave near the southern Jiangsu coast is impacted significantly. Besides, further experiments by adding thin dam in the Southern Yellow Sea are studied and discussed. The results illustrate the existence of the tidal wave from the Northern Yellow Sea, which is important for the formation of the rotating tidal wave system in the Southern Yellow Sea.","Southern Yellow Sea; Jiangsu coast; rotating tidal wave systemt; tidal current; Delft3D","en","conference paper","Tsinghua University Press","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:19b4afa6-3026-4c26-b9ae-2a9f950ddb63","http://resolver.tudelft.nl/uuid:19b4afa6-3026-4c26-b9ae-2a9f950ddb63","A data model for route planning in the case of forest fires","Wang, Z.; Zlatanova, S.; Moreno, A.; Van Oosterom, P.J.M.; Toro, C.","","2013","The ability to guide relief vehicles to safety and quickly pass through environments affected by fires is critical in fighting forest fires. In this paper, we focus on route determination in the case of forest fires, and propose a data model that supports finding paths among moving obstacles. This data model captures both static information, such as the type of the response team, the topology of the road network, and dynamic information, such as sensor information, changing availabilities of roads during disasters, and the position of the vehicle. We use a fire simulation model to calculate the fire evolution. The spread of the fire is represented as movements of obstacles that block the responders? path in the road network. To calculate safe and optimal routes avoiding obstacles, the A? algorithm is extended to consider the predicted availabilities of roads. We prove the optimality of the path calculated by our algorithm and then evaluate it in simulated scenarios. The results show that our model and algorithm are effective in planning routes that avoid one or more fire-affected areas and that the outlook for further investigation is promising.","emergency navigation; fire simulation; data model; algorithm","en","journal article","Elsevier","","","","","","","","Architecture and The Built Environment","OTB","","","",""
"uuid:27fb34e4-a530-401b-96e7-b221a9521314","http://resolver.tudelft.nl/uuid:27fb34e4-a530-401b-96e7-b221a9521314","Between Flexibility and Reliability: Changing Planning Culture in China","Wang, C.Y.","Bekkering, H. (promotor); Hsia, C.J. (promotor)","2013","In recent years, China has undoubtedly undergone a dramatic process of urban growth and transformation. Apart from its speed and scope, what is less recognized is that these processes are confronting the Chinese planning institutions with new and unexpected demands almost on daily basis. In reference to the increasing importance of private investments and developments within Chinese urbanization, a new balance between public planning and private developments, between top down and bottom up approaches is required which is able to generate both, a reliable and responsible framework for long-term urban development and a flexible system of implementation that meets the needs of changing conditions and new demands. The starting point of this research is to investigate to what extent the evolution of urban planning has developed after the opening up of reform, under the state-led and market-driven modes of Chinese reformation. Another focus, then, is studying how the different modes and various actors have influenced urban planning, through cumulative research based on analyses of the respective political and economic changes within initial reformation, in general, and planning, in particular. This study investigates the conditions, approaches and results of contemporary urban planning in China by analysing the developments in one of the fastest growing cities of the country: Shenzhen, located in the Pearl River Delta, can be regarded as an almost newly constructed city with approximately 300.000 inhabitants in 1980 and reaching 10.47 million in 2011. During a relatively short period of development the degree of acceleration and scope of an entirely unexpected growth forced local planning authorities to constantly readapt to changing conditions and new demands. Investigating the contemporary urban transformation and urban development processes in China can allow us to outline the new planning culture of contemporary China as related to its historical roots and traditional characteristics in a consistent time framework. It argues that the changing role of urban planning is strongly embedded into the political, economic, and social domains and is a part of cultural innovation.","critical modernity; planning culture; flexibility and reliability","en","doctoral thesis","","","","","","","","","Architecture and The Built Environment","Urbanism","","","",""
"uuid:d87f4fa9-d6b2-4fdc-bac1-915a7d321e81","http://resolver.tudelft.nl/uuid:d87f4fa9-d6b2-4fdc-bac1-915a7d321e81","Behaviours of a Ship Passing through a Lock under the Influence of a Berthed Ship","Wang, H.Z.; Zou, Z.J.","","2013","In this paper, a numerical study on the behaviours of a ship passing through a lock under the influence of a berthed ship is carried out. The viscous flow and hydrodynamic forces are calculated by applying an unsteady RANS code with a RNG k-å turbulence model. UDF is compiled to define the ship motion. The numerical results are obtained and analyzed for the cases of the berthed ship at different longitudinal and transverse position in the approaching channel to investigate the influences of the berthed ships postion on the ship-ship and ship-lock hydrodynamic interaction.","ship behaviour; lock; berthed ship; hydrodynamic interaction; numerical solution","en","conference paper","","","","","","","","","","","","","",""
"uuid:1b4a3aae-945d-4b34-8fa2-e57bc91beb8d","http://resolver.tudelft.nl/uuid:1b4a3aae-945d-4b34-8fa2-e57bc91beb8d","Improving moving jam detection performance with V2I communication","Netten, B.; Hegyi, A.; Wang, M.; Schakel, W.J.; Yuan, Y.; Schreiter, T.; Van Arem, B.; Van Leeuwen, C.; Alkim, T.","","2013","","safety and traffic management; speed advice; moving jam detection","en","conference paper","ITS Japan","","","","","","","","Civil Engineering and Geosciences","Transport & Planning","","","",""
"uuid:e7dc5eb4-eade-4195-bf9e-87571efa9ccb","http://resolver.tudelft.nl/uuid:e7dc5eb4-eade-4195-bf9e-87571efa9ccb","Challenges in modeling ice floods on the Ningxia-Inner Mongolia reach of the Yellow River, China","Fu, C.; Popescu, I.; Wang, C.; Mynett, A.E.; Zhang, F.","","2013","During winter the Yellow River in China is frequently subjected to ice flood disasters. Possible dike-breaking due to ice floods poses a serious threat to the part of the region located along the river, in particular the Ning-Meng reach (including Ningxia Hui and the Inner Mongolia Autonomous Region). Due to its special geographical location and river flow direction, the ice dams and jams lead to dike-breaking and overtopping on the embankment, which has resulted in huge casualties and property losses throughout history. Therefore, there is a growing need to develop capability in forecasting and analysing river ice floods. Research into ice floods along the river is taking place at the Yellow River Conservancy Commission (YRCC). A numerical model is one of the essential parts of the current research going on at the YRCC, which can be used to supplement the inadequacies in the field and lab studies which are being carried out to help understand the physical processes of river ice on the Yellow River. Based on the available data about the Ning-Meng reach of the Yellow River, the YRCC River Ice Dynamic Model (YRIDM) has been tested for capabilities to conduct ice flood forecasting. The YRIDM can be applied to simulate water level, discharge, water temperature, and ice cover thickness under unsteady-state conditions. Different scenarios were designed to explore the model uncertainty for two bounds (5% and 95%) and probability distribution. The YRIDM is an unsteady-state flow model that can show the basic regular pattern of ice floods; hence it can be used as an important tool to support decision-making. The recommendation is that data and research should be continued in order to support the model and to measure improvements.","","en","journal article","European Geosciences Union","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:82a5fd94-7bb9-4a55-8e34-fbbaa3d81f11","http://resolver.tudelft.nl/uuid:82a5fd94-7bb9-4a55-8e34-fbbaa3d81f11","Epidemic threshold and topological structure of susceptible-infectious-susceptible epidemics in adaptive networks","Guo, D.; Trajanovski, S.; Van de Bovenkamp, R.; Wang, H.; Van Mieghem, P.F.A.","","2013","The interplay between disease dynamics on a network and the dynamics of the structure of that network characterizes many real-world systems of contacts. A continuous-time adaptive susceptible-infectious-susceptible (ASIS) model is introduced in order to investigate this interaction, where a susceptible node avoids infections by breaking its links to its infected neighbors while it enhances the connections with other susceptible nodes by creating links to them. When the initial topology of the network is a complete graph, an exact solution to the average metastable-state fraction of infected nodes is derived without resorting to any mean-field approximation. A linear scaling law of the epidemic threshold ?c as a function of the effective link-breaking rate ? is found. Furthermore, the bifurcation nature of the metastable fraction of infected nodes of the ASIS model is explained. The metastable-state topology shows high connectivity and low modularity in two regions of the ?,? plane for any effective infection rate ?>?c: (i) a “strongly adaptive” region with very high ? and (ii) a “weakly adaptive” region with very low ?. These two regions are separated from the other half-open elliptical-like regions of low connectivity and high modularity in a contour-line-like way. Our results indicate that the adaptation of the topology in response to disease dynamics suppresses the infection, while it promotes the network evolution towards a topology that exhibits assortative mixing, modularity, and a binomial-like degree distribution.","","en","journal article","American Physical Society","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Intelligent Systems","","","",""
"uuid:5cc0832a-ef4f-457d-aec9-731b91cac403","http://resolver.tudelft.nl/uuid:5cc0832a-ef4f-457d-aec9-731b91cac403","Using Smart Controlled AC and Ceiling Fan to Save Energy","Wang, P-H.; Lin, J-Y.","","2013","This research aimed to explore the energy savings through the use of smart control as well as ceiling fan in intelligent building. As the energy consumption of air-conditioning (AC) accounts for about 40% of total residential energy, therefore, applying smart control system to the use of AC to achieve the effects of comfy and energy savings should be able to generate positive effect for the energy consumption of overall residential. This study used the smart control system in the intelligent building lab to transmit message to AC for its implementation of next operating step through the indoor temperature sensor in order to achieve energy saving effect","intelligent building; smart control; energy saving; ZigBee; smart living","en","conference paper","","","","","","","","","","","","","",""
"uuid:ebf2bc59-bd81-4b20-b2c5-91cc02d58862","http://resolver.tudelft.nl/uuid:ebf2bc59-bd81-4b20-b2c5-91cc02d58862","Resonance Based Flapping Wing Micro Air Vehicle","Goosen, J.F.L.; Peters, H.J.; Wang, Q.; Tiso, P.; Van Keulen, A.","","2013","","","en","conference paper","","","","","","","","","Mechanical, Maritime and Materials Engineering","Precision and Microsystems Engineering","","","",""
"uuid:a7673088-dc1c-40b9-879b-9c0d7ae0b65e","http://resolver.tudelft.nl/uuid:a7673088-dc1c-40b9-879b-9c0d7ae0b65e","Automatic estimation of excavation volume from laser mobile mapping data for mountain road widening","Wang, J.; González-Jorge, H.; Lindenbergh, R.; Arias-Sánchez, P.; Menenti, M.","","2013","Roads play an indispensable role as part of the infrastructure of society. In recent years, society has witnessed the rapid development of laser mobile mapping systems (LMMS) which, at high measurement rates, acquire dense and accurate point cloud data. This paper presents a way to automatically estimate the required excavation volume when widening a road from point cloud data acquired by an LMMS. Firstly, the input point cloud is down-sampled to a uniform grid and outliers are removed. For each of the resulting grid points, both on and off the road, the local surface normal and 2D slope are estimated. Normals and slopes are consecutively used to separate road from off-road points which enables the estimation of the road centerline and road boundaries. In the final step, the left and right side of the road points are sliced in 1-m slices up to a distance of 4 m, perpendicular to the roadside. Determining and summing each sliced volume enables the estimation of the required excavation for a widening of the road on the left or on the right side. The procedure, including a quality analysis, is demonstrated on a stretch of a mountain road that is approximately 132 m long as sampled by a Lynx LMMS. The results in this particular case show that the required excavation volume on the left side is 8% more than that on the right side. In addition, the error in the results is assessed in two ways. First, by adding up estimated local errors, and second, by comparing results from two different datasets sampling the same piece of road both acquired by the Lynx LMMS. Results of both approaches indicate that the error in the estimated volume is below 4%. The proposed method is relatively easy to implement and runs smoothly on a desktop PC. The whole workflow of the LMMS data acquisition and subsequent volume computation can be completed in one or two days and provides road engineers with much more detail than traditional single-point surveying methods such as Total Station or GPS profiling. A drawback is that an LMMS system can only sample what is within the view of the system from the road.","mobile laser scanning; road engineering; 2D slope; volume estimation","en","journal article","MDPI","","","","","","","","Civil Engineering and Geosciences","Geoscience and Remote Sensing","","","",""
"uuid:534b8005-7767-4bda-92cb-fb7c7b8f8d1f","http://resolver.tudelft.nl/uuid:534b8005-7767-4bda-92cb-fb7c7b8f8d1f","Optimal hovering kinematics with respect to various flapping-wing shapes","Wang, Q.; Goosen, J.F.L.; Van Keulen, A.","","2013","","","en","conference paper","","","","","","","","","Mechanical, Maritime and Materials Engineering","Precision and Microsystems Engineering","","","",""
"uuid:5dd2ae41-b46b-4312-a3bb-8772ae117897","http://resolver.tudelft.nl/uuid:5dd2ae41-b46b-4312-a3bb-8772ae117897","Topology of molecular interaction networks","Winterbach, W.; Van Mieghem, P.; Reinders, M.; Wang, H.; De Ridder, D.","","2013","Molecular interactions are often represented as network models which have become the common language of many areas of biology. Graphs serve as convenient mathematical representations of network models and have themselves become objects of study. Their topology has been intensively researched over the last decade after evidence was found that they share underlying design principles with many other types of networks. Initial studies suggested that molecular interaction network topology is related to biological function and evolution. However, further whole-network analyses did not lead to a unified view on what this relation may look like, with conclusions highly dependent on the type of molecular interactions considered and the metrics used to study them. It is unclear whether global network topology drives function, as suggested by some researchers, or whether it is simply a byproduct of evolution or even an artefact of representing complex molecular interaction networks as graphs. Nevertheless, network biology has progressed significantly over the last years. We review the literature, focusing on two major developments. First, realizing that molecular interaction networks can be naturally decomposed into subsystems (such as modules and pathways), topology is increasingly studied locally rather than globally. Second, there is a move from a descriptive approach to a predictive one: rather than correlating biological network 1 topology to generic properties such as robustness, it is used to predict specific functions or phenotypes. Taken together, this change in focus from globally descriptive to locally predictive points to new avenues of research. In particular, multi-scale approaches are developments promising to drive the study of molecular interaction networks further.","","en","journal article","BioMed Central","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Network Architectures and Services Group (NAS)","","","",""
"uuid:d0c537c0-cf3a-4cd5-bf7e-4215a95a5a5e","http://resolver.tudelft.nl/uuid:d0c537c0-cf3a-4cd5-bf7e-4215a95a5a5e","Experimental Study on Cementitious Composites Embedded with Organic Microcapsules","Wang, X.; Xing, F.; Zhang, M.; Han, N.; Qian, Z.","","2013","The recovery behavior for strength and impermeability of cementitious composites embedded with organic microcapsules was investigated in this study. Mortar specimens were formed by mixing the organic microcapsules and a catalyst with cement and sand. The mechanical behaviors of flexural and compression strength were tested. The results showed that strength could increase by up to nine percent with the addition of a small amount of microcapsules and then decrease with an increasing amount of microcapsules. An orthogonal test for investigating the strength recovery rate was designed and implemented for bending and compression using the factors of water/cement ratio, amount of microcapsules, and preloading rate. It is shown that the amount of microcapsules plays a key role in the strength recovery rate. Chloride ion permeability tests were also carried out to investigate the recovery rate and healing effect. The initial damage was obtained by subjecting the specimens to compression. Both the recovery rate and the healing effect were nearly proportional to the amount of microcapsules. The obtained cementitious composites can be seen as self-healing owing to their recovery behavior for both strength and permeability.","self-healing concrete; organic microcapsules; permeability; recovery rate; healing effect","en","journal article","MDPI","","","","","","","","Civil Engineering and Geosciences","Structural Engineering","","","",""
"uuid:328930cc-d48e-44ae-9cfb-03aa3d0dc429","http://resolver.tudelft.nl/uuid:328930cc-d48e-44ae-9cfb-03aa3d0dc429","Aging Assessment and Reliability Aware Computing Platforms","Wang, Y.","Bertels, K.L.M. (promotor)","2013","Aggressive CMOS technology feature size scaling has been going on for the past decades, while the supply voltage is not proportionally scaled. Due to the increasing power density and electric field in the gate dielectric, the accelerating factors of failure mechanisms in nanoscale Integrated Circuits (ICs) have become more severe than ever. As a result, maintaining IC reliability at the desired level becomes a critical challenge at both design-time and runtime. Addressing the pessimistic reliability landscape outlook over current and future technology nodes, this dissertation investigates reliability-aware design and management techniques to ensure the reliability and quality of IC products. With our special interests on the time-dependent device parameter degradations due to intrinsic failure mechanisms, we focus our discussion on: (i) runtime reliability assessment, (ii) aging degradations, and (iii) mitigation techniques that enable reliability-aware computation. To this end we propose a Dynamic Reliability Management (DRM) framework to combat the aging-induced degradation. In order to achieve a quantitative management, dedicated online aging sensors are employed in the proposed framework to extract dynamic degradation information from circuits. We first propose a unified aging model for the emerging FinFET devices as the physical basis for understanding the underlying aging degradation. Then, we introduce two types of aging sensors, based on threshold voltage and power supply current measurement, respectively, to assist online reliability assessment in DRM systems. Next, we introduce a compensation technique to manage 6T SRAM cell stability under spatial and temporal variations, by threshold voltage modulation using back-gate biasing of independent-gate FinFET devices. We conclude the dissertation by presenting a lifetime reliability modeling and enhancement framework, which demonstrates how to utilize the aging information from dedicated low-level aging sensors to maintain the overall IC health status within prescribed bounds.","Reliability; Reliability Aware Computation; Dynamic Reliability Management; Reliability Assessment","en","doctoral thesis","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Software and Computer Technology","","","",""
"uuid:266266e8-a237-431f-8cb3-54643dba3d5d","http://resolver.tudelft.nl/uuid:266266e8-a237-431f-8cb3-54643dba3d5d","Sustained release of BMP-2 in bioprinted alginate for osteogenicity in mice and rats","Poldervaart, M.T.; Wang, H.; Van der Stok, J.; Weinans, H.H.; Leeuwenburgh, S.C.G.; Cumhur Öner, F.; Dhert, W.J.A.; Alblas, J.","","2013","The design of bioactive three-dimensional (3D) scaffolds is a major focus in bone tissue engineering. Incorporation of growth factors into bioprinted scaffolds offers many new possibilities regarding both biological and architectural properties of the scaffolds. This study investigates whether the sustained release of bone morphogenetic protein 2 (BMP-2) influences osteogenicity of tissue engineered bioprinted constructs. BMP-2 loaded on gelatin microparticles (GMPs) was used as a sustained release system, which was dispersed in hydrogel-based constructs and compared to direct inclusion of BMP-2 in alginate or control GMPs. The constructs were supplemented with goat multipotent stromal cells (gMSCs) and biphasic calcium phosphate to study osteogenic differentiation and bone formation respectively. BMP-2 release kinetics and bioactivity showed continuous release for three weeks coinciding with osteogenicity. Osteogenic differentiation and bone formation of bioprinted GMP containing constructs were investigated after subcutaneous implantation in mice or rats. BMP-2 significantly increased bone formation, which was not influenced by the release timing. We showed that 3D printing of controlled release particles is feasible and that the released BMP-2 directs osteogenic differentiation in vitro and in vivo.","","en","journal article","Public Library of Science PLOS","","","","","","","","Mechanical, Maritime and Materials Engineering","Biomechanical Engineering","","","",""
"uuid:fad5c41f-74b7-439f-9ffa-4f44b2843446","http://resolver.tudelft.nl/uuid:fad5c41f-74b7-439f-9ffa-4f44b2843446","Enhanced Bone Regeneration of Cortical Segmental Bone Defects Using Porous Titanium Scaffolds Incorporated with Colloidal Gelatin Gels for Timeand Dose-Controlled Delivery of Dual Growth Factors","Van der Stok, J.; Wang, H.; Yavari, S.A.; Siebelt, M.; Sandker, M.; Waarsing, J.H.; Verhaar, J.A.N.; Jahr, H.; Zadpoor, A.A.; Leeuwenburgh, S.C.G.; Weinans, H.","","2013","Porous titanium scaffolds are a promising class of biomaterials for grafting large bone defects, because titanium provides sufficient mechanical support, whereas its porous structure allows bone ingrowth resulting in good osseointegration. To reinforce porous titanium scaffolds with biological cues that enhance and continue bone regeneration, scaffolds can be incorporated with bioactive gels for time- and dose-controlled delivery of multiple growth factors (GFs). In this study, critical femoral bone defects in rats were grafted with porous titanium scaffolds incorporated with nanostructured colloidal gelatin gels. Gels were loaded with bone morphogenetic protein-2 (BMP-2, 3 mg), fibroblast growth factor-2 (FGF-2, 0.6 mg), BMP-2, and FGF-2 (BMP-2/FGF-2, ratio 5:1) or were left unloaded. GF delivery was controlled by fine tuning the crosslinking density of oppositely charged nanospheres. Grafted femurs were evaluated using in vivo and ex vivo micro-CT, histology, and three-point bending tests. All porous titanium scaffolds containing GF-loaded gels accelerated and enhanced bone regeneration: BMP-2 gels gave an early increase (0–4 weeks), and FGF-2 gels gave a late increase (8–12 weeks). Interestingly, stimulatory effects of 0.6 mg FGF-2 were similar to a fivefold higher dose of BMP-2 (3 mg). BMP-2/FGF-2 gels gave more bone outside the porous titanium scaffolds than gels with only BMP-2 or FGF-2, resulted in bridging of most defects and showed superior bone-implant integrity in three-point bending tests. In conclusion, incorporation of nanostructured colloidal gelatin gels capable of time- and dose-controlled delivery of BMP-2 and FGF-2 in porous titanium scaffolds is a promising strategy to enhance and continue bone regeneration of large bone defects.","","en","journal article","Mary Ann Liebert","","","","","","","","Mechanical, Maritime and Materials Engineering","Biomechanical Engineering","","","",""
"uuid:1ae6b8a8-b097-4578-a149-58f92ccf4ba6","http://resolver.tudelft.nl/uuid:1ae6b8a8-b097-4578-a149-58f92ccf4ba6","Programmable architecture for quantum computing","Chen, J.; Wang, L.; Charbon, E.; Wang, B.","","2013","A programmable architecture called “quantum FPGA (field-programmable gate array)” (QFPGA) is presented for quantum computing, which is a hybrid model combining the advantages of the qubus system and the measurement-based quantum computation. There are two kinds of buses in QFPGA, the local bus and the global bus, which generate the cluster states and general multiqubit rotations around the z axis, respectively. QFPGA consists of quantum logic blocks (QLBs) and quantum routing channels (QRCs). The QLB is used to generate a small quantum logic while the QRC is used to combine them properly for larger logic realization. Considering the error accumulating on the qubus, the small logic is the general two-qubit quantum gate. However, for the application such as n-qubit quantum Fourier transform, one QLB can be reconfigured for four-qubit quantum Fourier transform. Although this is an implementation-independent architecture, we still make a rough analysis of its performance based on the qubus system. In a word, QFPGA provides a general architecture to integrate different quantum computing models for efficient quantum logic construction.","","en","journal article","American Physical Society","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Microelectronics","","","",""
"uuid:0114b1b5-0c35-4ab9-9794-27556fd0ec56","http://resolver.tudelft.nl/uuid:0114b1b5-0c35-4ab9-9794-27556fd0ec56","Effect of the interconnected network structure on the epidemic threshold","Wang, H.; Li, Q.; D'Agostino, G.; Havlin, S.; Stanley, H.E.; Van Mieghem, P.","","2013","Most real-world networks are not isolated. In order to function fully, they are interconnected with other networks, and this interconnection influences their dynamic processes. For example, when the spread of a disease involves two species, the dynamics of the spread within each species (the contact network) differs from that of the spread between the two species (the interconnected network). We model two generic interconnected networks using two adjacency matrices, A and B, in which A is a 2N×2N matrix that depicts the connectivity within each of two networks of size N, and B a 2N×2N matrix that depicts the interconnections between the two. Using an N-intertwined mean-field approximation, we determine that a critical susceptible-infected-susceptible (SIS) epidemic threshold in two interconnected networks is 1/?1(A+?B), where the infection rate is ? within each of the two individual networks and ?? in the interconnected links between the two networks and ?1(A+?B) is the largest eigenvalue of the matrix A+?B. In order to determine how the epidemic threshold is dependent upon the structure of interconnected networks, we analytically derive ?1(A+?B) using a perturbation approximation for small and large ?, the lower and upper bound for any ? as a function of the adjacency matrix of the two individual networks, and the interconnections between the two and their largest eigenvalues and eigenvectors. We verify these approximation and boundary values for ?1(A+?B) using numerical simulations, and determine how component network features affect ?1(A+?B). We note that, given two isolated networks G1 and G2 with principal eigenvectors x and y, respectively, ?1(A+?B) tends to be higher when nodes i and j with a higher eigenvector component product xiyj are interconnected. This finding suggests essential insights into ways of designing interconnected networks to be robust against epidemics.","","en","journal article","American Physical Society","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Intelligent Systems","","","",""
"uuid:3e3d348c-fdc2-4646-8a59-954ad70f7dea","http://resolver.tudelft.nl/uuid:3e3d348c-fdc2-4646-8a59-954ad70f7dea","Groundwater–surface water interactions, vegetation dependencies and implications for water resources management in the semi-arid Hailiutu River catchment, China – a synthesis","Zhou, Y.; Wenninger, J.; Yang, Z.; Yin, L.; Huang, J.; Hou, L.; Wang, X.; Zhang, D.; Uhlenbrook, S.","","2013","During the last decades, large-scale land use changes took place in the Hailiutu River catchment, a semi-arid area in northwest China. These changes had significant impacts on the water resources in the area. Insights into groundwater and surface water interactions and vegetation-water dependencies help to understand these impacts and formulate sustainable water resources management policies. In this study, groundwater and surface water interactions were identified using the baseflow index at the catchment scale, and hydraulic and water temperature methods as well as event hydrograph separation techniques at the sub-catchment scale. The results show that almost 90% of the river discharge consists of groundwater. Vegetation dependencies on groundwater were analysed from the relationship between the Normalized Difference Vegetation Index (NDVI) and groundwater depth at the catchment scale and along an ecohydrogeological cross-section, and by measuring the sap flow of different plants, soil water contents and groundwater levels at different research sites. The results show that all vegetation types, i.e. trees (willow (Salix matsudana) and poplar (Populus simonii), bushes (salix – Salix psammophila), and agricultural crops (maize – Zea mays)), depend largely on groundwater as the source for transpiration. The comparative analysis indicates that maize crops use the largest amount of water, followed by poplar trees, salix bushes, and willow trees. For sustainable water use with the objective of satisfying the water demand for socio-economical development and to prevent desertification and ecological impacts on streams, more water-use-efficient crops such as sorghum, barley or millet should be promoted to reduce the consumptive water use. Willow trees should be used as wind-breaks in croplands and along roads, and drought-resistant and less water-use intensive plants (for instance native bushes) should be used to vegetate sand dunes.","","en","journal article","European Geosciences Union (EGU)","","","","","","","","Civil Engineering and Geosciences","Water Management","","","",""
"uuid:10624e3e-a0e7-4107-bcca-7dcd99120bb6","http://resolver.tudelft.nl/uuid:10624e3e-a0e7-4107-bcca-7dcd99120bb6","3D APTV measurements on microbubble streaming","Rossi, M.; Marin, A.; Wang, C.; Hilgenfeldt, S.; Kähler, C.J.","","2013","Ultrasound-driven gas bubbles can be used as active actuators to create or modify the flow in microfluidic devices. Oscillating bubbles are able to create a steady streaming flow that can be used to perform several tasks in microfluidic devices. In this work, we focus on a specific configuration with a bubble located at a side wall of a microfluidic channel, for applications in size-sensitive sorting of microparticles. The flow in such configuration is often assumed to be two-dimensional, however 3D effects can be expected especially close to the top and bottom walls. In order to investigate the three-dimensional extension of the flow in such devices, we used the 3D Astigmatism Particle Tracking Velocimetry (APTV), to measure the trajectories and velocity of 2-?m-particles moving in the streaming flow. The primary aim of this investigation is to resolve the volumetric flow induced by a bubble with complex vibrational modes with 3D velocimetry methods, to characterize the three dimensional characteristics of the streaming flow.","","en","conference paper","","","","","","","","","","","","","",""
"uuid:af7b8411-59e6-48a6-adb8-cbecf0b6d5a8","http://resolver.tudelft.nl/uuid:af7b8411-59e6-48a6-adb8-cbecf0b6d5a8","Opaque flow measurement in the pipe system using echo-PIV and UDV method","Wang, K.; Tu, X.C.; Kim, H.B.","","2013","In this paper, echo-PIV and UDV technique were applied to measure the velocity fields of a pipe flow system. The working fluid is mixture of water and kaolin particle. The flow rate of mixture is 0.15 lpm. The error of peak velocity between echo-PIV and UDV were obtained and compared with the theoretical values. This study indicates the feasibility of echo-PIV and UDV methods for measuring the opaque flow which flow medium is water-kaolin mixture.","","en","conference paper","","","","","","","","","","","","","",""
"uuid:02586292-8ff1-4c20-bca4-bea2f5a56677","http://resolver.tudelft.nl/uuid:02586292-8ff1-4c20-bca4-bea2f5a56677","Coping with the uncertainties in the climate change adaptation of river dikes using risk-aversion economic optimization","Wang, L.; Van Gelder, P.H.A.J.M.; Vrijling, J.K.; Ranasinghe, R.W.M.R.J.B.; Maskey, S.","","2013","To guarantee a safe flood defence in a changing environment, the adaptation to climate change needs to be considered in the design of river dikes. However, the large uncertainty in the projections of future climate leads to varied estimations of future flood probability. How to cope with the uncertainties in future flood probability under climate change is an inevitable question in the adaptation. In this paper, the uncertainty introduced by climate projections was integrated into the ‘expected predictive flood probability’, and the risk-aversion attitude was introduced in the adaptation of river dikes. In detail, the uncertain effect of climate change on flood probability was represented by the uncertainty in the parameters of the probabilistic model. This parameter uncertainty was estimated based on the outputs from the GCMs participated in IPCC AR4. The parameter uncertainty estimated from different GCMs under selected scenarios was integrated into the expected predictive probability of flooding, which was used in the risk-aversion economic optimization. Different optimal results were obtained based on varied values of the risk-aversion index. The case of Bengbu Dike in China was studied as an example using the proposed approach. The results show that the uncertain effect of climate change causes an increase of optimal dike height but a decrease of the optimal safety level. The proposed approach enables decision makers to cope with the uncertain effects of climate change by adjusting their risk-aversion attitude.","climate change; uncertainty; risk-aversion optimisation","en","conference paper","European Water Resources Association (EWRA)","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:073e9289-67b9-437c-b63a-7684374a11ee","http://resolver.tudelft.nl/uuid:073e9289-67b9-437c-b63a-7684374a11ee","The tidal wave system in the Chinese marginal seas","Su, M.; Stive, M.J.F.; Zhang, C.K.; Yao, P.; Chen, Y.P.; Wang, Z.B.","","2013","A 2D large-scale tidal wave model is set up for the Chinese marginal seas and it is proved to simulate the tidal motion in this large domain well. Based on the model, sensitivity analyses have been carried out to investigate the influences of various factors on the tidal wave system. According to the results, the effect of river discharges and the tidal generating force on the whole tidal wave system is not obvious, but they do have influence in the shallow water area. In addition, the results show that sea level rise will impact on the China coast more than on the west coast of Korea. Furthermore, this paper demonstrates that the Shandong Peninsula is not the crucial reason for the formation of the radial tidal current off Jiangsu coast. A better insight into the propagation mechanism of the tidal wave in the Chinese marginal seas is obtained.","Chinese marginal seas; tidal wave; tidal current; radial sand ridges; Jiangsu coast; Delft 3D","en","conference paper","Bordeaux University","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:55aa3067-6d17-4a29-a15a-b01505664c94","http://resolver.tudelft.nl/uuid:55aa3067-6d17-4a29-a15a-b01505664c94","EBB-tidal delta morphology in response to a storm surge barrier","Eelkema, M.; Wang, Z.B.; Stive, M.J.F.","","2013","The ebb-tidal delta of the Eastern Scheldt tidal inlet has been under the influence of a storm surge barrier for the past 25 years. This barrier caused a strong decrease in average tidal currents through the inlet. The morphological response of the ebb-tidal delta is characterized by several different processes: (1) an overall decrease in sediment volume and morphological activity, (2) downdrift reorientation of channels and shoals, (3) a redistribution of sediment between channels and shoals, and (4) a lack of sediment exchange with the basin. Simulations with a process-based model show that the reorientation is a result of changed balance between cross-shore and alongshore tidal currents. The sediment volume decrease is a result of decreased tidal currents in combination with wind waves and a lack of sediment supply.","tidal inlet; Eastern Scheldt; ebb-tidal delta; storm surge barrier; morphodynamics","en","conference paper","Bordeaux University","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:c96fe364-4586-4ce7-95d7-1735dc0a36c7","http://resolver.tudelft.nl/uuid:c96fe364-4586-4ce7-95d7-1735dc0a36c7","The genesis of the radial tidal current off the Central Jiangsu Coast","Yao, P.; Wang, Z.B.; Zhang, C.K.; Su, M.; Chen, Y.P.; Stive, M.J.F.","","2013","One of the characteristics of the radial sand ridge field (RSRF) in the South Yellow Sea off the Jiangsu coast is the distinctive radial tidal current field. Although many studies have focused on the hydrodynamic environment around radial sand ridges, the knowledge on the genesis of the radial tidal current is still in a very basic stage. This paper attempts to explore the formation mechanism of the local radial tidal current field by a schematized process-based model. Two factors which are hypothesized to be responsible for the radial tidal current pattern are investigated: coastline shape, and the submarine topography. The results show that the schematized model sufficiently represents the real pattern of the tidal wave propagation in the South Yellow Sea. A preliminary description of the formation mechanism and main influence factors are obtained through sensitive analysis.","radial tidal current field; radial sand ridges; formation mechanism; schematized model; tidal wave","en","conference paper","Bordeaux University","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:202c854d-2d02-40db-9140-46dee7f91452","http://resolver.tudelft.nl/uuid:202c854d-2d02-40db-9140-46dee7f91452","Performance assessment of cement-based materials blended with micronized sand: Microstructure, durability and sustainability","Wang, Y.","Van Breugel, K. (promotor); Haas, E.M. (promotor); Ye, G. (promotor)","2013","Concrete is one of the most important construction materials in the world. However, Portland cement which is one of the constituents of concrete is responsible for about 5-10% of global CO2 emission. From sustainability point of view, therefore, it is important to search for materials which can be used to reduce or to replace Portland cement in concrete. Among the mineral admixtures micronized sand with high purity SiO2 has been selected as cement replacement. Micronized sand is produced by grinding of quartz sand, which is the most abundant mineral in the earth’s crust. Therefore, the use of this material will not cause a depletion of resources. The objective of this research is to investigate the possibility of using micronized sand to partially replacement cement in concrete. The performance of cement-based material with micronized sand as partial replacement of cement was evaluated with respect to the microstructure, durability and sustainability both experimentally and by numerical simulations.","cement-based material; micronized sand; microstructure; transport properties; service life; sustainability; CO2 footprint","en","doctoral thesis","VSSD Science and Technology","","","","","","","","Civil Engineering and Geosciences","Structural Engineering","","","",""
"uuid:9a06cb7d-c6fe-41e1-9e05-63d30bce6dbf","http://resolver.tudelft.nl/uuid:9a06cb7d-c6fe-41e1-9e05-63d30bce6dbf","Morphological modeling using a fully coupled, total variation diminishing upwind-biased centered scheme","Li, W.; De Vriend, H.J.; Wang, Z.; Van Maren, D.S.","","2013","High-resolution morphological modeling of fluvial processes with complex, rapidly varying flows has been limited so far by model accuracy or computational efficiency. One of the most widely used numerical algorithms is based on the total variation diminishing method, solved by either upwind or centered approaches. An upwind scheme preserves high accuracy but is complex and computationally demanding, whereas the simplicity and efficiency of a centered approach compromise the accuracy. The present paper extends a recent upwind-biased centered scheme originally developed for clear water and scalar transport over a rigid bed, to sediment-laden flows over an erodible bed. It does so by developing a fully coupled 2-D mathematical model using a finite volume method for structured grids. The complete set of noncapacity-based governing equations, involving the effects of bed deformation and sediment density variation, as well as the influences of turbulence and sediment diffusion, and the temporal and spatial scales needed for sediment adaptation, is solved at one time to obtain synchronous solutions for the entire computational domain. For stability, a two-stage splitting approach together with a second-order Runge-Kutta method is employed for the source terms. The model is verified in a number of tests covering a wide range of complex (sediment-laden) flows. The model is demonstrated to accurately simulate shock waves and reflection waves, but also rapid bed deformations at high sediment transport rates. The combination of high numerical accuracy and computational efficiency makes the model an important tool to forecast flood events in morphologically complex areas.","morphological modeling; coupled solution; upwind-biased centered scheme; finite volume method; sediment transport; erodible bed; dam break","en","journal article","American Geophysical Union","","","","","","","2013-12-20","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:4375c56e-24b6-44a0-9c37-27c483542034","http://resolver.tudelft.nl/uuid:4375c56e-24b6-44a0-9c37-27c483542034","Hydrogel encapsulated bacterial spores for self-healing concrete: Proof of concept","Wang, J.Y.; Van Vlierberghe, S.; Dubruel, P.; Verstraete, W.; De Belie, N.","","2013","Self-healing concrete is regarded as a promising solution to reduce the high maintenance and repair cost of concrete infrastructure. Due to the limited autogenous healing capacity of concrete as such, additives are needed to enhance its self-healing properties. Among various strategies, microbial-based self-healing has gained increasing attention because of its distinct features including environmental friendliness, long-term viability and low cost. Within the framework of this strategy, bacteria and the relevant bio-reagents are pre-added into the concrete during the casting and are expected to play their role (heal cracks) when cracking occurs. Due to the high alkalinity and small pore sizes of concrete, bacteria cannot be added directly, and hence an immobilization process is required prior to incorporation into concrete. In the present work, a bio-compatible hydrogel was evaluated as the carrier to encapsulate an efficient carbonate precipitating bacteria, Bacillus sphaericus, which was selected based on previous research. As proof of concept, the activity of bacterial spores after immobilization, the carbonatogenesity of the hydrogel encapsulated spores, the influence of the bio-agents on the hydrogel swelling properties, and the crack healing efficiency were investigated. Interestingly, no significant viability loss was observed after the immobilization process. The precipitation of CaCO3 in/on the hydrogel matrix by the encapsulated spores was demonstrated by thermogravimetric analysis (TGA). The swelling capacity of the hydrogel was slightly increased after incorporation of the bio-agents. In addition, the specimens combined with the bio-hydrogels showed an obvious superiority in crack healing efficiency, both with respect to the healing rate as well as the maximum healed crack width. A maximum crack width of about 0.5mm can be healed in the specimens containing bio-hydrogels within 7d, while no crack healing was observed in the reference specimens. The feasibility of using hydrogel immobilized bacteria for self-healing concrete is therefore demonstrated.","self-healing; concrete; hydrogel; bacterial spores; microbial CaCO3","en","conference paper","","","","","","","","","","","","","",""
"uuid:18d64886-55ce-40c5-b7ba-c97475a4a60a","http://resolver.tudelft.nl/uuid:18d64886-55ce-40c5-b7ba-c97475a4a60a","Interaction between microcapsules and cementitious matrix after cracking in a self-healing system","Wang, X.; Xing, F.; Zhang, M.; Han, N.; Qian, Z.","","2013","A new type of self-healing cementitious composites by using organic microcapsules is designed in Guangdong Key Laboratory of Durability for Coastal Civil Engineering, Shenzhen University. For the organic microcapsules, the shell material is urea formoldehyde (UF), and the core healing agent is Epoxy. The effect of organic microcapsules on mechanical behaviors of the composite specimens and the interaction between an organic microcapsule and an approaching crack is investigated in this study. The mechanical behaviors of bending and compression strengths for mortar specimens are tested. The results show that the strength may increase with a small amount of microcapsules and then decrease with increasing of microcapsules. The FEM numerical simulation is carried out to study the interaction between a crack and a microcapsule in the concrete matrix. It is known that there exist two possibilities when a crack approaches a microcapsule, the microcapsule is ruptured or debonded from the matrix. The self-healing function is based on the rupture of microcapsules. Thus determination of judgment criterion (The physical trigger mechanism-cracking) that under what condition a microcapsule ruptures is necessary. For simplicity, a two-dimensional plane square area is considered, in which the side length is 1 cm. A microcapsule of radius 0.1mm is located at the center of the area. Left hand side is a line crack. The interface between the microcapsule and the mortar matrix, as well as the bonding behavior of the microcapsule shell wall is modeled using the cohesive traction-separation constitutive relationship. The actual parameters of the materials may lead to rupture or debonding of a microcapsule. Through numerical simulation, the criterion of the possible failure pattern for a microcapsule is obtained in terms of the intensity of microcapsule wall, the intensity of the interface, thickness of the microcapsule wall, location of the crack, and the microcapsule radius.","self-healing concrete; organic microcapsules; interaction, crack; debonding","en","conference paper","","","","","","","","","","","","","",""
"uuid:f10debd8-2f20-4710-b9cb-df3c710db23b","http://resolver.tudelft.nl/uuid:f10debd8-2f20-4710-b9cb-df3c710db23b","Binding crystalline solids at low temperatures","Chen, Z.; Xu, Z.; Wang, G.; Li, H.; Chen, B.; Zeng, X.C.; Tan, L.","","2013","Crystalline solids are solid materials whose constituent atoms, molecules, or ions are arranged in a highly regulated fashion. Due to lack of rotational freedom in their stacking, they have been known as fragile materials. Even though some efforts have been dedicated to bind or mend defects/cracks in amorphous materials like concrete or polymers, welding or binding a crystalline solid at ambient or low temperature conditions is quite a challenging task. Mainly, low interface mobility from the atomic or ionic constituents frequently limits interface regroupings. We recently found that one type of crystalline solid, dubbed metal-organic frameworks (MOFs), shows interfacial binding capability in their solid state. MOFs are molecularly engineered crystals that are mechanically rigid but structurally dynamic and reconfigurable. Unlike traditional studies on surface area and porous structures, our particular interest is placed on surface repairing or regrouping activities. For instance, when defects on bulk MOFs are mended using our process, the solids show a modulus leap from 4 to 12 GPa and hardness from 400 to 1000 MPa. When solids are made as polymer composite, open wounds can be healed at ambient conditions. Moreover, we found that low temperatures down to -56 ºC did not appear to restrict this solid binding process, making it outstanding for low temperature healing or binding. If our results are utilized for many other MOFs that are adopted as catalysts or hydrogen storage/separation materials, we expect their structure integrity can be kept after multiple cycles of packing or extensive uses. Furthermore, the knowledge gained will help people design future crystalline solids or ordered structures that can be assembled, repaired or healed in various engineering applications.","supramolecules; crystalline solids; metal-organic frameworks; self-healing","en","conference paper","","","","","","","","","","","","","",""
"uuid:edf1127b-59ed-458d-b587-c10bf0a6ec7e","http://resolver.tudelft.nl/uuid:edf1127b-59ed-458d-b587-c10bf0a6ec7e","Design of microcapsule system used for self-healing cementitious material","Zhang, M.; Han, N.; Xing, F.; Wang, X.; Schlangen, H.E.J.G.","","2013","For a microcapsule based self-healing system in the cementitious material, a fundamental issue is to find and facilitate a suitable microcapsule system, concerning either the material selection or design and manufacture process. In this study, urea formaldehyde resin is used for the shell of microcapsule, and bisphenol an epoxy resin E-51 diluted by n-butyl glycidy ether (BGE) is adopted as the heal-agent inside the microcapsule. The production process mainly includes pre-polymerization preparation, emulsification, acidification and curing stage. The fundamental reaction mechanisms with respect to the synthesis process and the properties of the obtained microcapsule are discussed in this paper. Meanwhile, the healing mechanism by means of catalyst MC120D is further explored. Results show that the microcapsule obtained with the adopted production process can be used for the self-healing system in the cementitious materials.","self-healing; microcapsule; in situ polymerization; activation energy; reaction order; curing kinetics","en","conference paper","","","","","","","","","","","","","",""
"uuid:d4f3adb4-b991-4d42-824b-84ef2630edfd","http://resolver.tudelft.nl/uuid:d4f3adb4-b991-4d42-824b-84ef2630edfd","The smart releasing behavior of a microcapsule based on chemical self-healing system caused by chemical trigger activation","Dong, B.; Wang, Y.; Han, N.; Xing, F.","","2013","A novel chemical self-healing system based on microcapsule technology for cementitious composites is established in Guangdong Key Laboratory of Durability for Coastal Civil Engineering, Shenzhen University. The key issue of this system is how to release the healing material and how to activate the healing mechanism. In this paper, the study is focused on the releasing behavior. The smart releasing behavior of healing material in the microcapsule is characterized by EDTA (Ethylene Diamine Tetraacetic Acid) titration method. The experimental results show that releasing procedure of the corrosion inhibitor covered with PS is a function of the time, and is controlled by the wall thickness of the microcapsule. Moreover, the pH value affects the release rate of corrosion inhibitor. With the increasing of pH value, the releasing rate will increase greatly.","microcapsule; chemical self-healing; smart releasing behavior; EDTA","en","conference paper","","","","","","","","","","","","","",""
"uuid:74443d29-7373-42eb-8cde-bb325095f8c9","http://resolver.tudelft.nl/uuid:74443d29-7373-42eb-8cde-bb325095f8c9","Thermoplastic fibre stitching: A new self-healing method for carbon-epoxy composites","Pingkarawat, K.; Wang, C.H.; Varley, R.J.; Mouritz, A.P.","","2013","This paper presents an investigation into the delamination toughening and selfhealing properties of carbon-epoxy laminates using through-thickness stitches of mendable thermoplastic (poly[ethylene-co-(methacrylic acid)]). The effect of increasing stitch density on the improvement to the interlaminar fracture toughness and healing of mode I delamination cracks generated under static and fatigue interlaminar loads is determined. The self-healing and delamination toughening mechanisms of the mendable stitches are identified.","delamination; stitching; self-healing; mendable polymer; fracture toughness","en","conference paper","","","","","","","","","","","","","",""
"uuid:50984655-f8d7-4971-b433-a40c6e280ecc","http://resolver.tudelft.nl/uuid:50984655-f8d7-4971-b433-a40c6e280ecc","Evaluation of a microcapsule based self-healing system for cementitious materials","Zhang, M.; Han, N.; Xing, F.; Wang, X.; Schlangen, H.E.J.G.","","2013","An international cooperation research project has been financially supported by China Nature Science Foundation, which consists of three relatively independent, but strategically integrated research sub-programs, aiming at the formation of a selfhealing system based on the microcapsule principle for the cementitious composites. In this paper, a self-healing system triggered by physical process (cracking) is introduced. The healing material mainly consists of epoxy like materials. The discussion concerning microcapsule techniques are presented in another paper in this conference. This study mainly focuses on the two healing mechanisms: i.e. the mechanical recovery and the permeability related recovery. The primary test results concerning these healing mechanisms are presented and the healing effects on the relevant properties are further discussed.","self-healing; mircocapsule; healing effect; mechanical behaviour; permeability","en","conference paper","","","","","","","","","","","","","",""
"uuid:c3981060-1cba-434e-86c2-a7b107330489","http://resolver.tudelft.nl/uuid:c3981060-1cba-434e-86c2-a7b107330489","Most recent advances in the field of self-healing cementitious materials","Van Tittelboom, K.; Snoeck, D.; Wang, J.; De Belie, N.","","2013","While the Japanese researchers Ohama et al. [1] already mentioned in 1992 that a self-healing effect was noticed when polymer-modified concrete without hardener was made, the real pioneer in the research on self-healing concrete is Carolyn Dry from Illinois. The first time she proposed the use of encapsulated polymers to obtain self-healing concrete dates back to 1994 [2] and based on her publication output, she remained active within this field until 2003 [3, 4]. Within this timeframe, Victor Li started his research on fiber-reinforced self-healing concrete in Michigan [5]. From 2000 onwards other researchers in Japan (Mihashi, Nishiwaki et al.) [6-8], France (Granger et al.) [9], the United Kingdom (Joseph et al.) [10] and the Netherlands (ter Heide et al.) [11] started their research on self-healing cementitious materials. However, it was only in 2007, when the Dutch IOP program on self-healing was granted and the first international conference on self-healing materials was organized in the Netherlands, that self-healing concrete gained world-wide attention and all over the world research groups started working on this topic. One year later, in Belgium or more specifically at the Magnel Laboratory for Concrete Research of Ghent University, research on self-healing concrete started. In this keynote, an overview of the most recent developments within the Magnel Laboratory will be given.","alternative binders; fiber reinforcement; super absorbent polymers; encapsulated bacteria; encapsulated liquid polymers","en","conference paper","","","","","","","","","","","","","",""
"uuid:5d1d64f5-2883-4009-b291-538d2b9d1496","http://resolver.tudelft.nl/uuid:5d1d64f5-2883-4009-b291-538d2b9d1496","Evaluation of a microcapsule based self-healing system for cementitious materials","Zhang, M.; Han, N.; Xing, F.; Wang, X.; Schlangen, H.E.J.G.","","2013","An international cooperation research project has been financially supported by China Nature Science Foundation, which consists of three relatively independent, but strategically integrated research sub-programs, aiming at the formation of a selfhealing system based on the microcapsule principle for the cementitious composites. In this paper, a self-healing system triggered by physical process (cracking) is introduced. The healing material mainly consists of epoxy like materials. The discussion concerning microcapsule techniques are presented in another paper in this conference. This study mainly focuses on the two healing mechanisms: i.e. the mechanical recovery and the permeability related recovery. The primary test results concerning these healing mechanisms are presented and the healing effects on the relevant properties are further discussed.","self-healing; mircocapsule; healing effect; mechanical behaviour; permeability","en","conference paper","Magnel Laboratory for Concrete Research","","","","","","","","Civil Engineering and Geosciences","Structural Engineering","","","",""
"uuid:7a74cc18-967f-42a4-8b77-7948eb2c3a57","http://resolver.tudelft.nl/uuid:7a74cc18-967f-42a4-8b77-7948eb2c3a57","Interaction between microcapsules and cementitious matrix after cracking in a self-healing system","Wang, X.; Xing, F.; Zhang, M.; Han, N.; Qian, Z.","","2013","A new type of self-healing cementitious composites by using organic microcapsules is designed in Guangdong Key Laboratory of Durability for Coastal Civil Engineering, Shenzhen University. For the organic microcapsules, the shell material is urea formoldehyde (UF), and the core healing agent is Epoxy. The effect of organic microcapsules on mechanical behaviors of the composite specimens and the interaction between an organic microcapsule and an approaching crack is investigated in this study. The mechanical behaviors of bending and compression strengths for mortar specimens are tested. The results show that the strength may increase with a small amount of microcapsules and then decrease with increasing of microcapsules. The FEM numerical simulation is carried out to study the interaction between a crack and a microcapsule in the concrete matrix. It is known that there exist two possibilities when a crack approaches a microcapsule, the microcapsule is ruptured or debonded from the matrix. The self-healing function is based on the rupture of microcapsules. Thus determination of judgment criterion (The physical trigger mechanism-cracking) that under what condition a microcapsule ruptures is necessary. For simplicity, a two-dimensional plane square area is considered, in which the side length is 1 cm. A microcapsule of radius 0.1mm is located at the center of the area. Left hand side is a line crack. The interface between the microcapsule and the mortar matrix, as well as the bonding behavior of the microcapsule shell wall is modeled using the cohesive traction-separation constitutive relationship. The actual parameters of the materials may lead to rupture or debonding of a microcapsule. Through numerical simulation, the criterion of the possible failure pattern for a microcapsule is obtained in terms of the intensity of microcapsule wall, the intensity of the interface, thickness of the microcapsule wall, location of the crack, and the microcapsule radius.","self-healing concrete; organic microcapsules; interaction; crack; debonding","en","conference paper","Magnel Laboratory for Concrete Research","","","","","","","","Civil Engineering and Geosciences","Structural Engineering","","","",""
"uuid:d16e0833-ab3e-4d8a-b58b-bdaf1d50fb3e","http://resolver.tudelft.nl/uuid:d16e0833-ab3e-4d8a-b58b-bdaf1d50fb3e","A study on the steel corrosion protection of a microcapsule based self-healing cementitious system by means of electrochemical impedance spectroscopy","Dong, B.; Wang, Y.; Han, N.; Xing, F.","","2013","Based on microcapsule technology, a new type of self-healing system for cementitious composites is established. The performance of the system was characterized by means of electrochemical impedance spectroscopy of steel bars immersed in a simulated concrete environment. The results demonstrate strong inhibition of chloride-induced corrosion when microcapsules are added to the solution. A novel equivalent circuit model, which takes into account the inductive effect arising from the generation of corrosion products on the steel bar surface, is proposed to explain the protection performance of the microcapsules against steel bar corrosion in a concrete environment.","steel reinforced concrete; chemical trigger; chemical self-healing; electrochemical impedance spectroscopy (EIS); equivalent circuit model","en","conference paper","","","","","","","","","","","","","",""
"uuid:46c23c35-30fe-43e0-a4a1-ab9200627d11","http://resolver.tudelft.nl/uuid:46c23c35-30fe-43e0-a4a1-ab9200627d11","Intrinsic self-healing of polymer solid while keeping integrity and load-bearing capability","Rong, M.Z.; Zhang, M.Q.; Yuan, C.E.; Wang, F.","","2013","Generally, intrinsic self-healing polymers based on reversible covalent bonds scission and reconnection would lose their load bearing capability as a result of molecular cleavage during healing process. This shortcoming also results in creep deformation of the products. To solve the problem, we introduce a novel healing mechanism by using dynamically reversible C-ON bonds. Upon heating to a certain homolysis temperature, C-ON bonds in alkoxyamines moieties frequently cleave but immediately recombine. When alkoxyamines are incorporated into polymer chains, C-ON covalent bonds fission and recombination synchronously take place with very high frequency, and the equilibrium tends to the combination side. Cracked parts can thus be restored through chemical exchange reaction of alkoxyamine moieties. More importantly, because a large amount of C-ON bonds remain connection, the possible material deformation in the course of crack remending could be avoided. Here, crosslinked polystyrenes and epoxy with alkoxyamine moieties are synthesized as model polymers to prove feasibility of the above considerations. It is shown that the polymers can repeatedly self-heal cracks without deformation induced by chain scission, and provides the polymer with mechanical stability at elevated temperature as well. Moreover, the healing can be conducted within a wide temperature range when different alkoxyamines moieties are used. Molecular structures of alkoxyamines moieties, as well as thermodynamic behavior of C-ON bonds scission and recombination, etc., are studied in detail to optimize selfhealing behavior of the polymers. Full reversibility can be acquired when only one type of C-ON bond is included in the polymers. Accordingly, synthesis routes, molecular structures, thermally reversible characteristics, self-healing performance and self-healing mechanism, thermal stability and thermal-mechanical properties, etc, have been studied in detail.","polymer solid; intrinsic self-healing; alkoxyamines moieties; thermally dynamic reversible; load-bearing capability","en","conference paper","","","","","","","","","","","","","",""
"uuid:fb8040da-4359-4ea6-9468-30cfd670c542","http://resolver.tudelft.nl/uuid:fb8040da-4359-4ea6-9468-30cfd670c542","Morphodynamic development of the Yangtze and Scheldt Estuaries under influence of human interferences (abstract)","Wang, Z.B.; De Vriend, H.J.; Ding, P.","","2013","","","en","conference paper","IAHR","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:bc6adf64-b2c4-4801-8897-427de21681d8","http://resolver.tudelft.nl/uuid:bc6adf64-b2c4-4801-8897-427de21681d8","Relative role of bed roughness, bed erosion and channel storage on peak discharge increase in hyperconcentrated floods (abstract)","Li, W.; Wang, Z.B.; Van Maren, D.S.; De Vriend, H.J.; Wu, B.S.","","2013","","","en","conference paper","IAHR","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:cdc692e3-7910-4654-a912-9b7cb3efe3ec","http://resolver.tudelft.nl/uuid:cdc692e3-7910-4654-a912-9b7cb3efe3ec","Modelling Supported Driving as an Optimal Control Cycle: Framework and Model Characteristics","Wang, M.; Treiber, M.; Daamen, W.; Hoogendoorn, S.P.; Van Arem, B.","","2013","Driver assistance systems support drivers in operating vehicles in a safe, comfortable and efficient way, and thus may induce changes in traffic flow characteristics. This paper puts forward a receding horizon control framework to model driver assistance and cooperative systems. The accelerations of automated vehicles are controlled to optimise a cost function, assuming other vehicles driving at stationary conditions over a prediction horizon. The flexibility of the framework is demonstrated with controller design of Adaptive Cruise Control (ACC) and Cooperative ACC (C-ACC) systems. The proposed ACC and C-ACC model characteristics are investigated analytically, with focus on equilibrium solutions and stability properties. The proposed ACC model produces plausible human car-following behaviour and is unconditionally locally stable. By careful tuning of parameters, the ACC model generates similar stability charac- teristics as human driver models. The proposed C-ACC model results in convective downstream and absolute string instability, but not convective upstream string instability observed in human-driven traffic and in the ACC model. The control framework and analytical results provide insights into the influences of ACC and C-ACC systems on traffic flow operations.","advanced driver assistance systems; cooperative systems; car-following; optimal control; stability analyses","en","journal article","Elsevier","","","","","","","","Civil Engineering and Geosciences","Transport & Planning","","","",""
"uuid:7560c07e-795c-4d6d-9ff3-1bd45f59848d","http://resolver.tudelft.nl/uuid:7560c07e-795c-4d6d-9ff3-1bd45f59848d","Coastline modelling for nourishment strategy evaluation","Huisman, B.J.A.; Wang, Z.B.; De Ronde, J.G.; Stronkhorst, J.; Sprengers, C.J.","","2013","Coastal zone managers in the Netherlands require new dedicated tools for the assessment of the long-term impacts of coastal maintenance policies. The policies need to be evaluated on the impacts on multiple coastal functions in order to be able to optimize the performance of such strategies. This paper provides the technical backgrounds of such a model. A combined approach with a modified Pelnard-Considere (1956) coastline model and an ASMITA model (Stive & Wang, 2003) was used for this purpose.","","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:38d0f745-2191-4491-b709-69cb684308fb","http://resolver.tudelft.nl/uuid:38d0f745-2191-4491-b709-69cb684308fb","Driving Magnetostructural Transitions in Layered Intermetallic Compounds","Wang, J.L.; Caron, L.; Campbell, S.J.; Kennedy, S.J.; Hofmann, M.; Cheng, Z.X.; Md Din, M.F.; Studer, A.J.; Brück, E.; Dou, S.X.","","2013","We report the dramatic effect of applied pressure and magnetic field on the layered intermetallic compound Pr0.5Y0.5Mn2Ge2. In the absence of pressure or magnetic field this compound displays interplanar ferromagnetism at room temperature and undergoes an isostructural first order magnetic transition (FOMT) to an antiferromagnetic state below 158 K, followed by another FOMT at 50 K due to the reemergence of ferromagnetism as praseodymium orders (TCPr). The application of a magnetic field drives these two transitions towards each other, whereas the application of pressure drives them apart. Pressure also produces a giant magnetocaloric effect such that a threefold increase of the entropy change associated with the lower FOMT (at TCPr) is seen under a pressure of 7.5 kbar. First principles calculations, using density functional theory, show that this remarkable magnetic behavior derives from the strong magnetoelastic coupling of the manganese layers in this compound.","","en","journal article","American Physical Society","","","","","","","","Applied Sciences","RST/Radiation, Science and Technology","","","",""
"uuid:795cdadd-a2ab-41ce-ace3-0845478f08cb","http://resolver.tudelft.nl/uuid:795cdadd-a2ab-41ce-ace3-0845478f08cb","Slam induced loads on bow-flared sections with various roll angles","Wang, Shan; Guedes Soares, C.","","2013","","hydrodynamics","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:5d007cd8-50ae-41d4-ac90-e36f6e9ccd54","http://resolver.tudelft.nl/uuid:5d007cd8-50ae-41d4-ac90-e36f6e9ccd54","Computational ship hydrodynamics: Nowadays and way forward","Stern, F.; Yang, J.; Wang, Z.; Sadat-Hosseini, H.","","2013","","hydrodynamics","","journal article","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:a886f2a2-ddf4-46b2-8170-4d40168e21e8","http://resolver.tudelft.nl/uuid:a886f2a2-ddf4-46b2-8170-4d40168e21e8","Probabilistic modelling of the ultimate strength of ship plates with non-uniform corrosion","Teixeira, A.P.; Guedes Soares, C.; Wang, G.","","2013","","construction","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:a8819a30-8727-41a3-90a8-f626d31db30a","http://resolver.tudelft.nl/uuid:a8819a30-8727-41a3-90a8-f626d31db30a","Hydrodynamic development of inclined keel hull-propulsion","Seo, K.C.; Atlar, M.; Wang, D.","","2013","","resistance & propulsion","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:306af93f-fb6d-456c-97be-28f8b23e7f8d","http://resolver.tudelft.nl/uuid:306af93f-fb6d-456c-97be-28f8b23e7f8d","An experimental investigation into cavitation behaviour and pressure characteristics of alternative blade sections for propellers","Korkut, Emin; Atlar, Mehmet; Wang, Dazheng","","2013","","resistance & propulsion","","journal article","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:8a2d0c99-162f-479f-ad66-579176172b34","http://resolver.tudelft.nl/uuid:8a2d0c99-162f-479f-ad66-579176172b34","A 256 pixel magnetoresistive biosensor microarray in 0.18μm CMOS","Hall, Drew A. (Stanford University); Gaster, Richard S. (Stanford University); Makinwa, K.A.A. (TU Delft Electronic Instrumentation); Wang, Shan X. (Stanford University); Murmann, Boris (Stanford University)","","2013","Magnetic nanotechnologies have shown significant potential in several areas of nanomedicine such as imaging, therapeutics, and early disease detection. Giant magnetoresistive spin-valve (GMR SV) sensors coupled with magnetic nanotags (MNTs) possess great promise as ultra-sensitive biosensors for diagnostics. We report an integrated sensor interface for an array of 256 GMR SV biosensors designed in 0.18 μm CMOS. Arranged like an imager, each of the 16 column level readout channels contains an analog frontend and a compact ΣΔ modulator (0.054 mm2) with 84 dB of dynamic range and an input referred noise of 49
nT/√Hz. Performance is demonstrated through detection of an ovarian cancer biomarker, secretory leukocyte peptidase inhibitor (SLPI), spiked at concentrations as low as 10 fM. This system is designed as a replacement
for optical protein microarrays while also providing real-time kinetics monitoring.","Biochip; biosensor; GMR spin-valve; magnetic biosensor; proteomics; sigma delta modulator","en","journal article","","","","","","Accepted author version","","","","","Electronic Instrumentation","","",""
"uuid:6d512b7d-0c5a-44fd-8813-7784ca2d6c71","http://resolver.tudelft.nl/uuid:6d512b7d-0c5a-44fd-8813-7784ca2d6c71","Integrating spatio-temporal data into agent-based simulation for emergency navigation support","Wang, Z.","","2012","Emergency navigation for first responders in changing disasters is a very complex task and creates a new set of challenges for researchers. A lot of research work on this direction has been done. Nevertheless, traditional navigation systems consider only one responder with a pair of start and end points and the considered obstacles in previous studies are static. Moreover, none of the previous work has investigated the added value of integration of the disaster simulation with emergency navigation system. The goal of the research is to support the navigation task for multiple first responders in disasters by introducing the agent-based modeling and simulation integrated with spatio-temporal data. The general problem we are going to address is “how to navigate multiple first responders to multiple locations avoiding multiple obstacles”. For our purpose, this PhD project will be conducted as follows. First of all, we are going to investigate novel approaches to help navigate multiple first responders to avoid multiple obstacles, including both static obstacles and moving obstacles. By incorporating predictions of obstacles, one is able to anticipate changes in the road network and take them into consideration in the route determination process. A?er that, we will take advantage of the developments in current disaster simulation technology and integrate the disaster simulation model corrected with real time data into our navigation system. A prototype integrated navigation system linked with database will be developed. Besides, to help first responders evaluate navigation results, an agent-based modeling and simulation system updated with real time measurements will be proposed.","","en","report","Onderzoeksinstituut OTB","","","","","","","","OTB Research Institute for the Built Environment","OTB Research","","","",""
"uuid:d2185f76-94cf-4c98-a719-cf81ff538ea1","http://resolver.tudelft.nl/uuid:d2185f76-94cf-4c98-a719-cf81ff538ea1","A systematic and compatible classification of WEEE","Wang, F.; Huisman, J.; Balde, K.; Stevels, A.L.N.","","2012","","","en","conference paper","Fraunhofer Verlag","","","","","","","","Industrial Design Engineering","Design Engineering","","","",""
"uuid:946c0218-fae5-4472-be69-5f23abe8697d","http://resolver.tudelft.nl/uuid:946c0218-fae5-4472-be69-5f23abe8697d","A preliminary analysis of climate change effect on long-term risk-based design of flood defense","Wang, L.; Van Gelder, P.H.A.J.M.; Vrijling, J.K.","","2012","","","en","conference paper","European Geosciences Union","","","","","","","","Civil Engineering and Geosciences","Water Management","","","",""
"uuid:7384f3a7-cd04-4d7e-bf2a-6d116d2f9435","http://resolver.tudelft.nl/uuid:7384f3a7-cd04-4d7e-bf2a-6d116d2f9435","Tidal divides","Vroom, J.; Wang, Z.B.","","2012","","","en","conference paper","University of Twente","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:b96a2390-a293-42ab-813d-1e98f2b530ae","http://resolver.tudelft.nl/uuid:b96a2390-a293-42ab-813d-1e98f2b530ae","Ebb-tidal delta morphology in response to a storm surge barrier","Eelkema, M.; Wang, Z.B.; Hibma, A.","","2012","The Eastern Scheldt ebb-tidal delta morphology has been adapting for the past 25 years in response to the construction of the Eastern Scheldt storm-surge barrier in 1986. As a result of the barrier, there has been a decrease in tidal amplitudes, volumes, and average flow velocities, and there is hardly any sediment exchange through the barrier. Bathymetrical measurements of the ebb-tidal delta show multiple effects: (1) an overall decrease in sediment volume, (2) a decrease in morphological activity, (3) sedimentation in most channels, (4) northward reorientation of channels and shoals, and (5) an increase in wave-driven features. Some channels are showing stronger erosion since 1986. This, and the reorientation of other channels could be related to changes in the interaction between crossshore and alongshore tide. Most of the erosion is located in shallower, wave-dominated regions, indicating that waves have become relatively stronger. The steady erosive trend, combined with the decline of morphological activity, points toward a system dominated by relatively small and mostly negative bed-level changes. This system is still far from any kind of equilibrium, and is steadfastly adapting itself to the new hydraulic forcing regime, even though sediment transport capaci ies have decreased","","en","conference paper","University of Twente","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:dff70d1b-199f-406b-806e-03342e45c4da","http://resolver.tudelft.nl/uuid:dff70d1b-199f-406b-806e-03342e45c4da","Morphodynamic development and sediment budget of the Dutch Wadden Sea over the last century","Elias, E.P.L.; Van der Spek, A.J.F.; Wang, Z.B.; De Ronde, J.","","2012","The availability of nearly 100 years of bathymetric measurements allows the analysis of the morphodynamic evolution of the Dutch Wadden Sea under rising sea level and increasing human constraint. The historically observed roll-over mechanisms of landward barrier and coastline retreat cannot be sustained naturally due to numerous erosion control measures that have fixed the tidal basin and barrier dimensions. Nevertheless, the large continuous sedimentation in the tidal basins (nearly 600 million m3), the retained inlets and the similar channel-shoal characteristics of the basins during the observation period indicate that the Wadden Sea is resilient to anthropogenic influence, and can import sediment volumes even larger than those needed to compensate the present rate of sea-level rise. The largest sedimentation occurs in the Western Wadden Sea, where the influence of human intervention is dominant. The large infilling rates in closed-off channels, and along the basin shoreline, rather than a gradual increase in channel flat heights, render it likely that this sedimentation is primarily a response to the closure of the Zuiderzee and not an adaptation to sea-level rise. Most of the sediments were supplied by the ebb-tidal deltas. It is, however, unlikely that the sediment volume needed to reach a new equilibrium morphology in the Western Wadden Sea can be delivered by the remaining ebb-tidal deltas alone.","Wadden Sea; morphodynamics; tidal basins; ebb-tidal deltas; impact large-scale engineering works","en","conference paper","Netherlands Journal of Geosciences Foundation","","","","","","","2014-11-30","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:5f6d9a07-1e66-4875-ab30-29327a553042","http://resolver.tudelft.nl/uuid:5f6d9a07-1e66-4875-ab30-29327a553042","Modelling Driver Assitance Systems by Optimal Control","Wang, M.; Daamen, W.; Hoogendoorn, S.P.; van Arem, B.","","2012","Driver assistance systems support drivers in operating vehicles in a safe, comfortable and efficient way, and thus may induce changes in traffic flow characteristics. This paper put forward a receding horizon control framework to model driver assistance systems. The accelerations of automated vehicles are determined to optimise a cost function, assuming other vehicles driving at stationary conditions over a prediction horizon. The flexibility of the framework is demonstrated with controller design of Adaptive Cruise Control (ACC)systems. The proposed ACC model characteristics are investigated analytically, with focus on equilibrium solutions and stability properties. The proposed ACC model is unconditionally locally stable. By careful tuning of parameters, the ACC model generates similar stability characteristics as human driver models.","Driver Assitance Systems; optimal control; car-following; stability analyses","en","conference paper","TRAIL Research School","","","","","","","","Civil Engineering and Geosciences","Transport & Planning","","","",""
"uuid:04164ab8-8f91-47e5-9e35-f8528e7423b1","http://resolver.tudelft.nl/uuid:04164ab8-8f91-47e5-9e35-f8528e7423b1","3D Cadastre Oriented Reconstruction of Administrative Procedure in Chinese Urban Land Management","Guo, Renzhong; Luo, Ping; Jiang, Renrong; Wang, Weixi","","2012","Focusing on the recent management problem of 3D land utilization in the administrative procedure in China, this paper firstly elaborates the basic characteristics of land ownership and management in China, and then introduces the main concepts and steps in the current urban land management procedure, and reveals the deficiency in supporting 3D utilization for urban regions. Finally, from the perspective of 3D space and regarding 3D cadaster management as the core, this paper presents new administrative procedure of urban land management reconstructed from the recent procedure.","Land Management Procedure; 3D Cadastres","en","conference paper","","","","","","","","","","","","","",""
"uuid:6afd3112-26ef-48ba-abb6-e6246d3038fa","http://resolver.tudelft.nl/uuid:6afd3112-26ef-48ba-abb6-e6246d3038fa","Visualization Principles in 3D Cadastre: A First Assessment of Visual Variables","Wang, Chen; Pouliot, Jacynthe; Hubert, Frédéric","","2012","This paper proposes to investigate which among visual variables are more appropriate (if they are) for geo-visualization of 3D legal units in a probable 3D cadastre system. Visual variables, as proposed by Bertin (1983), include position, size, shape, value, color, orientation and texture. The appropriateness is evaluated base on whether a visual variable can be selective or not in the context of visualising 3D cadastral features. From a literature review, five requirements are identified and used to carry out the assessment. Namely they are represent bounded and partial bounded 3D legal units, represent the relationship between 3D legal units and 2D land parcels, represent the relationship of 3D legal units with corresponding physical object, represent spatial relationships among 3D legal units and label with official measurements. The results clearly show that changing the position of the visual variable for selectivity purpose is not an adequate strategy, except to distinguish bounded and unbounded 3D legal units. A change in size of point and line or in color is fully suitable no matter is the requirement. If there is light source and shading effect in 3D cadastre visualization, value is not a promising choice. However, in a self-illuminating situation, in which there is no light source and shading effect, value could be used to represent all situations. Labeling with official measurements is the requirement the least fulfil.","3D; visualization; visual variables; cadastre","en","conference paper","","","","","","","","","","","","","",""
"uuid:de4b307a-87bb-42a0-aa23-0e05a91ad463","http://resolver.tudelft.nl/uuid:de4b307a-87bb-42a0-aa23-0e05a91ad463","Domain Wall Propagation through Spin Wave Emission","Wang, X.S.; Yan, P.; Shen, Y.H.; Bauer, G.E.W.; Wang, X.R.","","2012","We theoretically study field-induced domain wall motion in an electrically insulating ferromagnet with hard- and easy-axis anisotropies. Domain walls can propagate along a dissipationless wire through spin wave emission locked into the known soliton velocity at low fields. In the presence of damping, the usual Walker rigid-body propagation mode can become unstable for a magnetic field smaller than the Walker breakdown field.","","en","journal article","American Physical Society","","","","","","","","Applied Sciences","QN/Quantum Nanoscience","","","",""
"uuid:55fa76ad-7b7a-4586-a66b-bd021170a87b","http://resolver.tudelft.nl/uuid:55fa76ad-7b7a-4586-a66b-bd021170a87b","Multidisciplinary Design and Optimization Framework for Aircraft Box Structures","Van Dijk, R.E.C.; Zhao, X.; Wang, H.; Van Dalen, F.","","2012","Competitive aircraft box structures are a perfect compromise between weight and price. The conceptual design process of these structures is a typical Multidisciplinary Design and Optimization effort, normally conducted by human engineers. The iterative nature of MDO turns development into a long and costly process. Knowledge-Based Engineering can be used to automate this process by capturing relevant design process knowledge, which is then re-used inside a computer application. This research will introduce a parametric, generative box model that has been developed using KBE techniques. The generality and rule-basedness of this model allows for the automatic generation of a wide range of box configurations and variants, thereby enabling a thorough exploration of the design space. Structural and price analyses tools have been coupled to the box model to generate the required discipline-specific performance data. With the product model and coupled analysis tools ready, the goal is to automatically optimize for minimum weight and price without human intervention. The design of Gulfstream 650 rudder is considered as initial use case, the first experiences of which are discussed in this paper.","multidisciplinary design optimization; knowledge-based engineering; knowledge engineering; aircraft box structures; design automation; cost estimation; finite elements modeling","en","conference paper","Royal Aeronautical Society","","","","","","","2013-08-10","Aerospace Engineering","Flight Performance and Propulsion","","","",""
"uuid:0a31b891-4f8f-4f0b-932b-de1f348838e2","http://resolver.tudelft.nl/uuid:0a31b891-4f8f-4f0b-932b-de1f348838e2","Maximum modular graphs","Trajanovski, S.; Wang, H.; Van Mieghem, P.","","2012","Modularity has been explored as an important quantitative metric for community and cluster detection in networks. Finding the maximum modularity of a given graph has been proven to be NPcomplete and therefore, several heuristic algorithms have been proposed. We investigate the problem of finding the maximum modularity of classes of graphs that have the same number of links and/or nodes and determine analytical upper bounds. Moreover, from the set of all connected graphs with a fixed number of links and/or number of nodes, we construct graphs that can attain maximum modularity, named maximum modular graphs. The maximum modularity is shown to depend on the residue obtained when the number of links is divided by the number of communities. Two applications in transportation networks and datacenters design that can benefit of maximum modular partitioning are proposed.","statistical and nonlinear physics","en","journal article","EDP Sciences/Springer","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Intelligent Systems","","","",""
"uuid:8b88ca00-045c-4541-b2d1-11605f76606c","http://resolver.tudelft.nl/uuid:8b88ca00-045c-4541-b2d1-11605f76606c","Assessment of the effects of the Zuider Sea closure on the hydrodynamics of the Wadden Sea inlets","Vroom, J.; Elias, E.; Lescinski, J.; Wang, Z.B.","","2012","Large hydrodynamic and morphodynamic changes have taken place in the western Dutch Wadden Sea due to the closure of the Zuider Sea in the early 1930s. Hydrodynamic simulations for three situations, viz. just before the closure, just after the closure and at present, have been carried out in order to investigate the hydrodynamic changes since the closure and to improve our understanding of the observed morphodynamic changes. The model results show a large increase in tidal range after the closure of the Zuider Sea. This increase continued to grow after the closure due to bathymetric change and sea level rise. The morphodynamic analysis focuses on the changed behavior of the ebb-tidal deltas of the Texel Inlet and the Vlie Inlet. Both ebb-tidal deltas have undergone a re-orientation in up drift direction. Two possible explanations based on the literature for this change are discussed with the help of the hydrodynamic simulations.","Wadden Sea; Zuider Sea; Delft3D modeling; tidal basins; basin area reduction; tidal asymmetry","en","conference paper","Coastal Engineering Research Council","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:01c7192b-c07e-4c50-91ab-cb84f3d85719","http://resolver.tudelft.nl/uuid:01c7192b-c07e-4c50-91ab-cb84f3d85719","Gibbs-Non-Gibbs Transitions via Large Deviations: Computable Examples","Redig, F.; Wang, F.","","2012","We give new and explicitly computable examples of Gibbs-non-Gibbs transitions of mean-field type, using the large deviation approach introduced in (van Enter et al. in Mosc. Math. J. 10:687–711, 2010). These examples include Brownian motion with small variance and related diffusion processes, such as the Ornstein-Uhlenbeck process, as well as birth and death processes. We show for a large class of initial measures and diffusive dynamics both short-time conservation of Gibbsianness and dynamical Gibbs-non-Gibbs transitions.","dynamical Gibbs-non-Gibbs transition; Feng-Kurtz formalism; bad configurations; unique and non-unique histories","en","journal article","Springer-Verlag","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Delft Institute of Applied Mathematics","","","",""
"uuid:3b7a7295-ed35-4485-aaa5-7534e1a68e6f","http://resolver.tudelft.nl/uuid:3b7a7295-ed35-4485-aaa5-7534e1a68e6f","The branching channel network in the Yangtze Estuary","Wang, Z.B.; Ding, P.X.","","2012","The channels in the Yangtze Estuary have an ordered-branching structure: The estuary is first divided by the Chongming Island into the North Branch and the South Branch. Then the South Branch is divided into the North Channel and South Channel by the Islands Changxing and Hengsha. The South Channel is again divided into the North and South Passage by the Jiuduansha Shoal. This three-level bifurcation and four-outlet configuration appears to be a natural character of the estuary, also in the past (Chen et al., 1982), although the whole system has been extending into the East China Sea in the southeast direction due to the abundant sediment supply from the Yangtze River. Recently, the natural development of the system seems to be substantially disturbed by human interferences, especially the Deep Navigation Channel Project. For the understanding of the behaviour of the bifurcating channel system in the estuary we present analysis on two aspects: (1) the equilibrium configuration of river delta distributary networks, and (2) influence of tidal flow on the morphological equilibrium of rivers. Based on the analyses we conclude that the branching channel structure of the Yangtze Estuary can be classified as tide-influenced river delta distributary networks. Its basic structure is the same as in case of river dominated delta. The empirical relations describing the basic features of the river-dominated distributary delta networks can be explained by theoretical analysis, although they are not fully satisfied by the Yangtze Estuary because of the influence of the tide. Two major influences of the tide are identified, viz. increasing the resistance to the river flow into the sea and increasing the sediment transport capacity. As consequence of these two influences the cross-sectional area of the river/estuary increases in the seawards direction and the bed slope decreases. The insights from the analyses are helpful for the understanding of the impact of the Deep Navigation Channel Project on the large scale morphological development of the estuary.","Yangtze Estuary; river delta; chanel network; tide; morphological equilibrium","en","conference paper","Coastal Engineering Research Council","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:0dd57a88-d582-42d8-93c3-610514df5b1f","http://resolver.tudelft.nl/uuid:0dd57a88-d582-42d8-93c3-610514df5b1f","Lindhard and RPA susceptibility computations in extended momentum space in electron-doped cuprates","Wang, Y.J.; Barbiellini, B.; Lin, H.; Das, T.; Basak, S.; Mijnarends, P.E.; Kaprzyk, S.; Markiewicz, R.S.; Bansil, A.","","2012","We present an approximation for efficient calculation of the Lindhard susceptibility ?L(q,?) in a periodic system through the use of simple products of real space functions and the fast Fourier transform (FFT). The method is illustrated by providing ?L(q,?) results for the electron doped cuprate Nd2?xCexCuO4 extended over several Brillouin zones. These results are relevant for interpreting inelastic x-ray scattering spectra from cuprates.","","en","journal article","American Physical Society","","","","","","","","Applied Sciences","RRR/Radiation, Radionuclides and Reactors","","","",""
"uuid:838ec651-1c5f-46b3-bd2b-34288fa6b812","http://resolver.tudelft.nl/uuid:838ec651-1c5f-46b3-bd2b-34288fa6b812","Disruption of Functional Brain Networks in Alzheimer’s Disease: What Can We Learn from Graph Spectral Analysis of Resting-State Magnetoencephalography?","De Haan, W.; Van der Flier, W.M.; Wang, H.; Van Mieghem, P.F.A.; Scheltens, P.; Stam, C.J.","","2012","In Alzheimer’s disease (AD), structural and functional brain network organization is disturbed. However, many of the present network analysis measures require a priori assumptions and methodological choices that influence outcomes and interpretations. Graph spectral analysis (GSA) is a more direct algebraic method that describes network properties, which might lead to more reliable results. In this study, GSA was applied to magnetoencephalography (MEG) data to explore functional network integrity in AD. Sensor-level resting-state MEG was performed in 18 Alzheimer patients (age 67 – 9, 6 women) and 18 healthy controls (age 66 – 9, 11 women). Weighted, undirected graphs were constructed based on functional connectivity analysis using the Synchronization likelihood, and GSA was performed with a focus on network connectivity, synchronizability, and node centrality. The main outcomes were a global loss of network connectivity and altered synchronizability in most frequency bands. Eigenvector centrality mapping confirmed the hub status of the parietal areas, and demonstrated a low centrality of the left temporal region in the theta band in AD patients that was strongly related to the mini mental state examination (global cognitive function test) score (r = 0.67, p = 0.001). Summarizing, GSA is a theoretically solid approach that is able to detect the disruption of functional network topology in AD. In addition to the previously reported overall connectivity losses and parietal area hub status, impaired network synchronizability and a clinically relevant left temporal centrality loss were found in AD patients. Our findings imply that GSA is valuable for the purpose of studying altered brain network topology and dynamics in AD.","dementia; eigenvector centrality; electrophysiology; functional connectivity; magnetoencephalography; network; neurophysiology; resting-state","en","journal article","Mary Ann Liebert","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:97743381-042e-4495-ad7c-bee12068ff3d","http://resolver.tudelft.nl/uuid:97743381-042e-4495-ad7c-bee12068ff3d","Recycling of Aluminum from Fibre Metal Laminates","Zhu, G.; Xiao, Y.; Yang, Y.; Wang, J.; Sun, B.; Boom, R.","","2012","Recycling of aluminum alloy scrap obtained from delaminated fibre metal laminates (FMLs) was studied through high temperature refining in the presence of a salt flux. The aluminum alloy scrap contains approximately mass fraction w(Cu) = 4.4%, w(Mg) = 1.1% and w(Mn) = 0.6% (2024 aluminum alloy). The main objective of this research is to obtain a high metal yield, while maintaining its original alloy compositions. The work focuses on the metal yield and quality of recycled Al alloy under different refining conditions. The NaCl-KCl salt system was selected as the major components of flux in the Al alloy recycling. Two different flux compositions were employed at NaCl to KCl mass ratios of 44:56 and 70:30 respectively, based on either the eutectic composition, or the European preference. Different additives were introduced into the NaCl-KCl system to study the effect of flux component on recycling result. Although burning and oxidation loss of the alloying elements during re-melting and refining take place as the drawbacks of conventional refining process, the problems can be solved to a large extent by using an appropriate salt flux. Experimental results indicate that Mg in the alloy gets lost when adding cryolite in the NaCl-KCl salt system, though the metal yield can reach as high as 98%. However, by adding w(MgF2) = 5% into the NaCl-KCl salt system (instead of using cryolite) all alloying elements were well controlled to its original composition with a metal yield of almost 98%.","Al-Cu-Mg alloy, 2024 Al, recycling, cryolite, salt flux","en","journal article","Springer-Verlag","","","","","","","","Mechanical, Maritime and Materials Engineering","Materials Science and Engineering","","","",""
"uuid:670a4d48-1736-409a-9847-8c077fa29bf8","http://resolver.tudelft.nl/uuid:670a4d48-1736-409a-9847-8c077fa29bf8","Degradation Behavior of Epoxy Resins in Fibre Metal Laminates Under Thermal Conditions","Zhu, G.; Xiao, Y.; Yang, Y.; Wang, J.; Sun, B.; Boom, R.","","2012","GLARE (glass fibre/epoxy reinforced aluminum laminate) is a member of the fiber metal laminate (FML) family, and is built up of alternating metal and fiber layers. About 500m2 GLARE is employed in each Airbus A380 because of the superior mechanical properties over the monolithic aluminum alloys, such as weight reduction, improved damage tolerance and higher ultimate tensile strength. Many tons of new GLARE scraps have been accumulated during the Airbus A380 manufacturing. Moreover, with the increasing plane orders of Airbus A380, more and more end-of-life (EOL) GLARE scrap will be generated after retire of planes within forty years. Thermal processing is a potential method for the material recycling and re-use from GLARE with the aim of environmental protection and economic benefits. The current study indicatdes that thermal delamination is a crucial pre-treatment step for the GLARE recycling. The decomposition behavior of the epoxy resins at elevated temperatures was investigated by using the simultaneous thermal analysis, thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC). Based on the thermal analysis results, GLARE thermal delamination experiments at refined temperatures were carried out to optimize the treatment temperature and holding time.","fibre metal laminates, GLARE (glass fibre/epoxy reinforced aluminum laminate), recycling, decomposition kinetics, thermal degradation","en","journal article","Springer-Verlag","","","","","","","","Mechanical, Maritime and Materials Engineering","Materials Science and Engineering","","","",""
"uuid:5ef03603-9045-4bdf-a1db-4842f2f82def","http://resolver.tudelft.nl/uuid:5ef03603-9045-4bdf-a1db-4842f2f82def","Do greedy assortativity optimization algorithms produce good results?","Winterbach, W.; De Ridder, D.; Wang, H.J.; Reinders, M.; Van Mieghem, P.","","2012","","","en","conference paper","EDP sciences","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Network Architectures and Services (NAS) Group","","","",""
"uuid:fa9cff1c-5a82-41b0-8b4a-fe3c4c50d81b","http://resolver.tudelft.nl/uuid:fa9cff1c-5a82-41b0-8b4a-fe3c4c50d81b","Comparison of dynamical decoupling protocols for a nitrogen-vacancy center in diamond","Wang, Z.H.; De Lange, G.; Riste, D.; Hanson, R.; Dobrovitski, V.V.","","2012","We perform a detailed theoretical-experimental study of the dynamical decoupling (DD) of the nitrogen-vacancy (NV) center in diamond. We investigate the DD sequences applied to suppress the dephasing of the electron spin of the NV center induced by the coupling to a spin bath composed of the substitutional nitrogen atoms. The decoupling efficiency of various DD schemes is studied, including both periodic and aperiodic pulse sequences. For ideal control pulses, we find that the DD protocols with the Carr-Purcell-Meiboom-Gill (CPMG) timing of the pulses provides best performance. We show that, as the number of control pulses increases, the decoupling fidelity scaling differs qualitatively from the predictions of the Magnus expansion, and explain the origin of this difference. In particular, more advanced symmetrized or concatenated protocols do not improve the DD performance. Next, we investigate the impact of the systematic instrumental pulse errors in different periodic and aperiodic pulse sequences. The DD protocols with the single-axis control do not preserve all spin components in the presence of the pulse errors, and the two-axis control is needed. We demonstrate that the two-axis control sequence with the CPMG timing is very robust with respect to the pulse errors. The impact of the pulse errors can be diminished further by symmetrizing this protocol. For all protocols studied here, we present a detailed account of the pulse error parameters which make the strongest impact on the DD performance. In conclusion, we give specific recommendations about choosing the decoupling protocol for the system under investigation.","","en","journal article","American Physical Society","","","","","","","","Applied Sciences","QN/Quantum Nanoscience","","","",""
"uuid:c711507b-cf08-4ef2-af1d-b7ae061b4913","http://resolver.tudelft.nl/uuid:c711507b-cf08-4ef2-af1d-b7ae061b4913","Morfologische ontwikkelingen van de Nederlandse Waddenzee","Wang, Z.B.; Speelman, H.; Hoeksma, R.; Gerritsen, H.","","2012","","","nl","conference paper","Nijgh Periodieken","","","","","","","","Civil Engineering and Geosciences","Water Management","","","",""
"uuid:3f902f4d-efab-4f0d-bb40-fc1252c660ca","http://resolver.tudelft.nl/uuid:3f902f4d-efab-4f0d-bb40-fc1252c660ca","Bulk Fermi surface and momentum density in heavily doped La2?xSrxCuO4 using high-resolution Compton scattering and positron annihilation spectroscopies","Al-Sawai, W.; Barbiellini, B.; Sakurai, Y.; Itou, M.; Mijnarends, P.E.; Markiewicz, R.S.; Kaprzyk, S.; Wakimoto, S.; Fujita, M.; Basak, S.; Lin, H.; Wang, Y.J.; Eijt, S.W.H.; Schut, H.; Yamada, K.; Bansil, A.","","2012","We have observed the bulk Fermi surface (FS) in an overdoped (x=0.3) single crystal of La2?xSrxCuO4 by using Compton scattering. A two-dimensional (2D) momentum density reconstruction from measured Compton profiles yields a clear FS signature in the third Brillouin zone along [100]. The quantitative agreement between density functional theory (DFT) calculations and momentum density experiment suggests that Fermi-liquid physics is restored in the overdoped regime. In particular the predicted FS topology is found to be in good accord with the corresponding experimental data. We find similar quantitative agreement between the measured 2D angular correlation of positron annihilation radiation (2D-ACAR) spectra and the DFT-based computations. However, 2D-ACAR does not give such a clear signature of the FS in the extended momentum space in either the theory or the experiment.","","en","journal article","American Physical Society","","","","","","","","Applied Sciences","RRR/Radiation, Radionuclides and Reactors","","","",""
"uuid:97f39293-64c7-43c1-9a1b-690ac568147f","http://resolver.tudelft.nl/uuid:97f39293-64c7-43c1-9a1b-690ac568147f","Some OFDM waveforms for a fully polarimetric weather radar","Van Genderen, P.; Krasnov, O.A.; Wang, Z.; Tigrek, R.F.","","2012","Retrieval of cloud parameters in weather radar benefits from polarimetric measurements. Most polarimetric radars measure the full backscatter matrix (BSM) using a few alternating polarized sounding signals. Using specially encoded orthogonal frequency division multiplexing (OFDM) signals however, the BSM can be measured in a single simultaneous transmission of two orthogonally polarized signals. Based on a set of parameters for weather radar, the properties of such a signal are explored and its merit as a useful capability is shown.","","en","journal article","Cambridge University Press","","","","","","","2013-02-22","Electrical Engineering, Mathematics and Computer Science","Telecommunications","","","",""
"uuid:6f76d5c3-5cc2-4cdf-a2af-d6cb1323e289","http://resolver.tudelft.nl/uuid:6f76d5c3-5cc2-4cdf-a2af-d6cb1323e289","Modelling of friction for high temperature extrusion of aluminium alloys","Wang, L.","Katgerman, L. (promotor)","2012","In recent years, finite-element (FE) simulations have been extensively used in scientific research and industrial practice to analyse the extrusion process. A basic issue of FE simulations is the accuracy of the results, which is mainly determined by the viscoplastic material behaviour of aluminium alloys at elevated temperatures and the determination of boundary conditions, especially the friction boundary condition. In this thesis, the determination of friction boundary conditions for hot aluminium extrusion process was done by using the short sliding distance ball-on-disc test at elevated temperatures. A mathematical model for high-temperature ball-on-disc tests was developed. This model is capable of discriminating the individual contributions of ploughing and shearing friction to the apparent friction. It was found that during high-temperature ball-on-disc tests, the friction coefficients obtained from ball-on-disc tests alone were insufficient to represent the frictional interaction between deforming aluminium and steel at elevated temperatures. Based on the ball-on-disc test results, a novel physically based friction model (adhesive strength friction model: ASFM) was developed for the bearing channel of an aluminium extrusion die. To verify this friction model, a novel extrusion testing method, double action extrusion (DAE), to highlight the effect of friction at the die bearing in aluminium extrusion was developed. The ASFM was implemented into the FE simulation of DAE tests, and good agreements between the FE predictions and experiments were obtained, indicating that ball-on-disc test is an effective way of characterizing the friction for the bearing channel of extrusion dies. For a further understanding of the DAE, a theoretical model was developed, and a good agreement between the modelling results and experiments was obtained. The theoretical modelling results revealed that the length difference of the extrudates was caused by the combined effects of friction and material rate dependency at elevated temperatures.","extrusion; friction; aluminium alloys","en","doctoral thesis","","","","","","","","","Mechanical, Maritime and Materials Engineering","Materials Science & Engineering","","","",""
"uuid:22297436-968d-4fae-81ba-34584d3ef57e","http://resolver.tudelft.nl/uuid:22297436-968d-4fae-81ba-34584d3ef57e","Community overlays upon real-world complex networks","Ge, X.; Wang, H.","","2012","Many networks are characterized by the presence of communities, densely intra-connected groups with sparser inter-connections between groups. We propose a community overlay network representation to capture large-scale properties of communities. A community overlay Go can be constructed upon a network G, called the underlying network, by (a) aggregating each community in G as a node in the overlay Go; (b) connecting two nodes in the overlay if the corresponding two communities in the underlying network have a number of direct links in between, (c) assigning to each node/link in the overlay a node/link weight, which represents e.g. the percentage of links in/between the corresponding underlying communities. The community overlays have been constructed upon a large number of real-world networks based on communities detected via five algorithms. Surprisingly, we find the following seemingly universal properties: (i) an overlay has a smaller degree-degree correlation than its underlying network ?o(Dl+,Dl?) < ?(Dl+,Dl?) and is mostly disassortative ?o(Dl+,Dl?) < 0; (ii) a community containing a large number Wi of nodes tends to connect to many other communities ?o(Wi,Di) > 0. We explain the generic observation (i) by two facts: (1) degree-degree correlation or assortativity tends to be positively correlated with modularity; (2) by aggregating each community as a node, the modularity in the overlay is reduced and so is the assortativity. The observation (i) implies that the assortativity of a network depends on the aggregation level of the network representation, which is illustrated by the Internet topology at router and AS level.","","en","journal article","Springer-Verlag","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Telecommunications","","","",""
"uuid:84120ccb-4358-4e66-96fa-97b0ecaf70fc","http://resolver.tudelft.nl/uuid:84120ccb-4358-4e66-96fa-97b0ecaf70fc","Position-controlled [100] InP nanowire arrays","Wang, J.; Plissard, S.; Hocevar, M.; Vu, T.T.T.; Zehender, T.; Immink, G.G.W.; Verheijen, M.A.; Haverkort, J.; Bakkers, E.P.A.M.","","2012","We investigate the growth of vertically standing [100] zincblende InP nanowire (NW) arrays on InP (100) substrates in the vapor-liquid-solid growth mode using low-pressure metal-organic vapor-phase epitaxy. Precise positioning of these NWs is demonstrated by electron beam lithography. The vertical NW yield can be controlled by different parameters. A maximum yield of 56% is obtained and the tapering caused by lateral growth can be prevented by in situ HCl etching. Scanning electron microscopy, high-resolution transmission electron microscopy, and micro-photoluminescence have been used to investigate the NW properties.","arrays; electron beam lithography; etching, III-V semiconductors; indium compounds; micro-optics; MOCVD; nanofabrication; nanowires; photoluminescence; scanning electron microscopy; semiconductor growth; transmission electron microscopy; vapour phase epitaxial growth","en","journal article","American Institute of Physics","","","","","","","","Applied Sciences","QN/Quantum Nanoscience","","","",""
"uuid:925b4799-91a3-4afc-af17-4d8a05b792ac","http://resolver.tudelft.nl/uuid:925b4799-91a3-4afc-af17-4d8a05b792ac","Reference-free time-based localization for an asynchronous target","Wang, Y.; Leus, G.J.T.","","2012","Low-complexity least-squares (LS) estimators based on time-of-arrival (TOA) or time-difference-of-arrival (TDOA) measurements have been developed to locate a target node with the help of anchors (nodes with known positions). They require to select a reference anchor in order to cancel nuisance parameters or relax stringent synchronization requirements. Thus, their localization performance relies heavily on the reference selection. In this article, we propose several reference-free localization estimators based on TOA measurements for a scenario, where anchor nodes are synchronized, and the clock of the target node runs freely. The reference-free LS estimators that are different from the reference-based ones do not suffer from a poor reference selection. Furthermore, we generalize existing reference-based localization estimators using TOA or TDOA measurements, which are scattered over different research areas, and we shed new light on their relations. We justify that the optimal weighting matrix can compensate the influence of the reference selection for reference-based weighted LS (WLS) estimators using TOA measurements, and make all those estimators identical. However, the optimal weighting matrix cannot decouple the reference dependency for reference-based WLS estimators using a nonredundant set of TDOA measurements, but can make the estimators using the same set identical as well. Moreover, the Cramér-Rao bounds are derived as benchmarks. Simulation results corroborate our analysis.","OA-Fund TU Delft","en","journal article","SpringerOpen","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Microelectronics","","","",""
"uuid:32566fa2-5fcf-424d-9aec-73f5c2a67604","http://resolver.tudelft.nl/uuid:32566fa2-5fcf-424d-9aec-73f5c2a67604","Tuning the stress induced martensitic formation in titanium alloys by alloy design","Li, C.; Chen, J.H.; Wu, X.; Wang, W.; Van der Zwaag, S.","","2012","","","en","journal article","Springer","","","","","","","","Aerospace Engineering","","","","",""
"uuid:6d3bd38d-cd35-446d-95a7-c172577f156f","http://resolver.tudelft.nl/uuid:6d3bd38d-cd35-446d-95a7-c172577f156f","Operationalising Public Space Activity and Structuring Redevelopment Trough Public Facilities Planning in a Configurational Urban Structure","Read, S.A.; Wang, J.","","2012","Forms in planning often do not match the forms of cities. This is important because the experience and functionings of cities are given by certain forms and not by others. In particular we are concerned here with the fact planning and design thinking often assumes a nested hierarchy of communities and spaces while the real forms of cities suggest a different diagram of how hierarchies are formed and sustained as active spaces. We ask the question what kind of forms human action and urban activity entail, and begin to answer this with a view taken from hermeneutical phenomenology that finds these mediated by technologies in such a way that what acts is the human?technology network rather than the human in a polar relation with a resistant ‘environment’. ‘Environments’ are, it is suggested, ‘technological spaces’ constructed in networks and to normative forms and scales like ‘neighbourhood’ or ‘city’. We review previous work on the role of the supergrid in constructing these forms in a process of historical development in Amsterdam. In Amsterdam infrastructure has been systematised to create networks of places in neighbourhoods, in cities (neighbourhoods and other city?scale things), and in metropolitan regions (cities and other metropolitan scaled things). This is a level of ‘planning’ that concerns normative assumptions and exists outside of the explicit concerns of planning while affecting all planning decisions at the level of sense. We conclude there is a different ‘diagram’ of urban space, consisting of three grids superimposed on each other, each of which produces a different normative element: neighbourhood, city and metropolitan region; each of which exists in part?whole relations with the others. We use this model to investigate the form of the city of Jinan in China, asking about its relevance and how we can use it to promote planning for an active public space in new towns in Jinan. Chinese planning assumes a particular form of the city and we contrast this with the actuality of activity patterns in Jinan and their historical formation. We ask how planning form needs to be translated here into urban form in order to promote public space activity in the new towns proposed and make some guidelines and suggestions for planners on how we can begin to do this. The question of why a model derived in European conditions may help us in China may be answered by the fact that both were subject of urbanisation under conditions of industrialisation and both are undergoing transformation under conditions of metropolitanisation. There is an open question still concerning Chinese ‘neighbourhoods’ and their definition.","public space activity; facilities planning; infrastructure planning; urban place; space syntax; Jinan; China","en","conference paper","PUC","","","","","","","","Architecture","Urbanism","","","",""
"uuid:ea565073-02c4-42e9-ba9c-3f89fa819e57","http://resolver.tudelft.nl/uuid:ea565073-02c4-42e9-ba9c-3f89fa819e57","A simple verification test for nonlinear flow calculations around a ship hull steadily advancing in calm water","Noblesse, Francis; Wang, Lijue; Yang, Chi","","2012","","hydrodynamics","","journal article","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:e5089dd3-101d-461d-a482-528d08ae2dbe","http://resolver.tudelft.nl/uuid:e5089dd3-101d-461d-a482-528d08ae2dbe","A knowledge intensive parametric modelling method to support ship layout design","Wang, C.; Hopman, J.J.","Hopman, J.J. (advisor)","2012","","","","conference paper","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Design, Production and Operation","","",""
"uuid:edb0dd1f-22ad-48ee-9ec8-3cd4ee126f04","http://resolver.tudelft.nl/uuid:edb0dd1f-22ad-48ee-9ec8-3cd4ee126f04","Analysis of the water impact of symmetric wedges with a multi-material Eulerian formulation","Wang, S.; Guedes Soares, C.","","2012","","hydrodynamics","","journal article","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:1948b758-d53f-41f2-bdb1-0dfe3e7be34f","http://resolver.tudelft.nl/uuid:1948b758-d53f-41f2-bdb1-0dfe3e7be34f","Yellow River delta: Support for sustainable development","De Vrees, L.; Wang, Z.B.; Marchand, M.","","2011","","","en","book chapter","Coastal & Marine Union (EUCC)","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:3ae31f05-b4ef-4a7e-bf2b-ecb0bc782e66","http://resolver.tudelft.nl/uuid:3ae31f05-b4ef-4a7e-bf2b-ecb0bc782e66","A study on sedimentation of tidal rivers and channels flowing into deep bay with a Delft3D model","Wang, Z.B.; Tse, M.L.; Lau, S.C.","","2011","For supporting Drainage Services Department of the Government of the Hong Kong SAR to develop a comprehensive strategy for overall land drainage and flood control in Yuen Long and North Districts, 3D hydrodynamic and sediment transport model is set up. The model deploys Domain Decomposition technique and covers the whole Deep Bay (the estuary of the Shenzhen River), the tidal sections of the rivers and drainage channels including Shenzhen River, Kam Tin River, Shan Pui River and Tin Shui Wai Main Drainage Channel flowing into Deep Bay and a part of the Pearl Estuary. As driving forces, the model takes into account waves and flow driven by wind, tide, river discharge and salt intrusion. Field surveys for wind waves, sediment concentration and especially sediment properties have been conducted. The collected data are analysed together with the existing data and used as basis for the set up of the model. The model is calibrated especially against the development of sedimentation in the Lower Shenzhen River since 2000, after a major deepening of the river. The model can be applied to predict sedimentation in Shenzhen River and tidal drainage channels for different scenarios concerning dredging strategy and river discharge regimes. The study has improved insights into the complicated hydrodynamic and morphodynamic system of Deep Bay together with the rivers and channels flowing into it.","","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:00f660de-a63d-4fbf-915e-c1825aa8e6b4","http://resolver.tudelft.nl/uuid:00f660de-a63d-4fbf-915e-c1825aa8e6b4","Support for the sustainable development of the Yellow River Delta","De Vrees, L.; Wang, Z.B.; Marchand, M.","","2011","The environment in the Yellow River Delta (YRD) is under stress from large socio-economic pressures, leading to air, soil and water pollution. A Sino-Dutch project the Sustainable Development YRD project (1995 – 1997) was undertaken with the principle goal of contributing to the sustainable, long-term development of the Yellow River Delta. Objectives and criteria for sustainable development were defined. One of the main project challenges was to show how to use the limited fresh water resources in a sustainable way. This was undertaken using integrated and analytical tools in which future developments and strategies were systematically analysed. Such an approach provides a strong incentive to begin communication and develop mutual understanding between the different responsible authorities and stakeholders.","","en","book chapter","Coastal & Marine Union - EUCC","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:b4ce5aa1-3aff-4439-b80f-86ce59d57964","http://resolver.tudelft.nl/uuid:b4ce5aa1-3aff-4439-b80f-86ce59d57964","Tidal flat evolution at the central Jiangsu coast, China","Gong, Z.; Wang, Z.B.; Stive, M.J.F.; Zhang, C.K.","","2011","A schematized process-based model of tidal flat evolution was constructed with dimensions similar to the tidal flats near the Wanggang Mouth at the central coast of Jiangsu, China. The simulated flow patterns agree qualitatively with field observations from literature, i.e. involving tidal asymmetry, current directions and tidal wave features. The analysis of the sediment fluxes depicts that deposition occurs from spring tide to neap tide and erosion from neap tide to spring tide. A sensitivity analysis test of the morphological acceleration factor shows that the ideal value is only 1, implying no acceleration factor. The long-term mudflat evolution has been simulated starting from an initial sand seabed. The simulated morphological characteristics, including the convex cross-shore profiles with steeper slope and the southern prograding coastline with slight higher accretion rate compared with the north side, are qualitatively consistent with reality. Most importantly, the creek patterns are roughly reproduced.","","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:ce5cd5e9-d8de-477f-aa9a-b7b353ee7ff2","http://resolver.tudelft.nl/uuid:ce5cd5e9-d8de-477f-aa9a-b7b353ee7ff2","Experimental investigation on breaching of embankments","Zhu, Y.; Visser, P.J.; Vrijling, J.K.; Wang, G.Q.","","2011","Breaching of embankments has recently drawn more and more attention due to its importance in the development of early warning systems for embankment failures, in the evacuation plans of people at risk, in the design method of embankments based on a risk-approach, etc. The erosion process observed during embankment breaching tests in the laboratory and the analysis of the results are described in this paper. Five embankments, one constructed with pure sand, four with different sand-silt-clay mixtures were tested. The height of the embankments was 75 cm and the width at the crest was 60 cm. Examination of the data from these tests indicated that headcut erosion played an important role in the process of breach growth in the embankments made of cohesive soil mixtures. Flow shear erosion, fluidization of the headcut slope surface, undermining of the headcut due to impinging jet scour and discrete soil mechanical slope mass failure from the headcut were all observed during these tests. For the embankment constructed with pure sand, the breach erosion process was dominated by shear erosion, which led to a gradual and relatively uniform retreat of the downstream slope. The cohesive proportion in the sand-silt-clay mixtures strongly slowed down the erosion process.","embankments; breaching; experiments; headcut; erosion","en","journal article","Science China Press and Springer","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:3f630242-12bd-4138-908c-7105e13f5fb6","http://resolver.tudelft.nl/uuid:3f630242-12bd-4138-908c-7105e13f5fb6","Interaction between hydrodynamics and salt marsh dynamics: An example from Jiangsu coast","Hu, Z.; Stive, M.J.F.; Zitman, T.J.; Ye, Q.H.; Wang, Z.B.; Luijendijk, A.; Gong, Z.; Suzuki, T.","","2011","Salt marshes are distributed along more than 400 km of the Jiangsu coast in Eastern China, which are regarded as important habitats and serve as coastal protection as well. Previous research has proven that salt-marsh vegetation can reduce current velocity and dampen waves by its stems and leaves. Reversely, hydrodynamic forces also have a significant influence on the growth of salt-marsh vegetation. To study the interaction between hydrodynamics and salt-marsh development on the Jiangsu coast, a 2D schematized model has been built by using a new interactive structure between flow, wave and vegetation modules of the process-based model Delft3D. In the hydrodynamic simulations, the impact of vegetation on waves and currents is quantified. In the vegetation growth module, the development of salt marshes is influenced by inundation time and shear stress from hydrodynamic simulations. The feedback loop is completed by hydrodynamic modules receiving the newly updated data of salt-marsh field from the vegetation growth module. The results show that wave height and current velocity are significantly influenced by vegetation. Reversely, the dynamics of marsh vegetation greatly rely on hydrodynamic conditions. Consequently, this interaction between hydrodynamics and salt marsh induces temporal variations of each other. In the model, the salt marsh is especially sensitive to the waves. Though wave height is relatively small on the Jiangsu coast, in terms of bed shear stress, waves may be of great importance to the development of salt marsh.","","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Waterbouwkunde","","","",""
"uuid:e0285ddd-675d-4546-b01c-f8f5e1c86d81","http://resolver.tudelft.nl/uuid:e0285ddd-675d-4546-b01c-f8f5e1c86d81","The correlation of metrics in complex networks with applications in functional brain networks","Li, C.; Wang, H.; De Haan, W.; Stam, C.J.; Van Mieghem, P.F.A.","","2011","An increasing number of network metrics have been applied in network analysis. If metric relations were known better, we could more effectively characterize networks by a small set of metrics to discover the association between network properties/metrics and network functioning. In this paper, we investigate the linear correlation coefficients between widely studied network metrics in three network models (B´arabasi–Albert graphs, Erd¨os–R´enyi random graphs and Watts–Strogatz small-world graphs) as well as in functional brain networks of healthy subjects. The metric correlations, which we have observed and theoretically explained, motivate us to propose a small representative set of metrics by including only one metric from each subset of mutually strongly dependent metrics. The following contributions are considered important. (a) A network with a given degree distribution can indeed be characterized by a small representative set of metrics. (b) Unweighted networks, which are obtained from weighted functional brain networks with a fixed threshold, and Erdös–Rényi random graphs follow a similar degree distribution. Moreover, their metric correlations and the resultant representative metrics are similar as well. This verifies the influence of degree distribution on metric correlations. (c) Most metric correlations can be explained analytically. (d) Interestingly, the most studied metrics so far, the average shortest path length and the clustering coefficient, are strongly correlated and, thus, redundant. Whereas spectral metrics, though only studied recently in the context of complex networks, seem to be essential in network characterizations. This representative set of metrics tends to both sufficiently and effectively characterize networks with a given degree distribution. In the study of a specific network, however, we have to at least consider the representative set so that important network properties will not be neglected.","neuronal networks (experiment); network dynamics; random graphs; networks; computational neuroscience","en","journal article","IOP/SISSA","","","","","","","2012-05-25","Electrical Engineering, Mathematics and Computer Science","Telecommunications","","","",""
"uuid:cf0b256c-a486-45c4-88e3-890172db7336","http://resolver.tudelft.nl/uuid:cf0b256c-a486-45c4-88e3-890172db7336","Localization and Communication for UWB-based Wireless Sensor Networks","Wang, Y.","Van der Veen, A.J. (promotor); Leus, G. (promotor)","2011","The great demand for location-aware wireless sensor networks (WSNs) motivates the research in this thesis. The unique characteristics of WSNs impose numerous challenges on localization and communication. In this thesis, we handle some key challenges and provide affordable solutions. Impulse radio ultra wideband (IR-UWB) is employed as the fundamental technology for both localization and communication due to its distinctive advantages in accurate ranging and reliable communication. The following aspects are treated in this thesis. Transmitted-reference (TR) UWB communication systems: IR-UWB processing in the digital domain usually asks for very high sampling rates. The TR-UWB scheme allows for sub-Nyquist rate sampling by correlating the received pulse sequence with its delayed version in the analog domain. Thus, it avoids the daunting Nyquist sampling rate, relaxes the stringent synchronization requirements, and only asks for aggregate channel coefficients. A data model including various kinds of interferences is employed, and then a complete receiver is proposed including signal detection, channel estimation, synchronization and equalization. Theoretical ranging bounds and practical ranging methods based on IR-UWB: We investigate the theoretical ranging accuracy of a novel method, which exploits the range information in both the amplitude and the time delay of the received signal. The investigations are conducted not only for an additive white Gaussian noise (AWGN) channel with attenuation, but also for an AWGN channel with both attenuation and shadowing. Furthermore, a practical ranging method based on time-of-arrival (TOA) estimation using UWB IRs is developed. Stroboscopic sampling is employed to sacrifice transmission efficiency for a lower sampling rate. Moreover, it can maintain the same ranging resolution as Nyquist sampling can achieve. Due to the long preamble required by stroboscopic sampling, the clock drift, which is an accumulative effect over time caused by the relative clock skew between different clocks, is one of the main error sources in TOA estimation. Therefore, TOA estimation methods with clock drift calibration are explored to dramatically mitigate the influence of the drift. Various localization and tracking methods: Extended multi-dimensional scaling (MDS): Since the classical MDS cannot be applied to general networks with missing links, we extend the classical MDS algorithm to deal with a special kind of network with specific missing links. Our goal is to jointly estimate the positions of all the nodes given partial pairwise distance measurements up to a translation, rotation, and reflection. Reference-free time-based localization: Low-complexity least-squares (LS) estimators based on time-of-arrival (TOA) or time-difference-of-arrival (TDOA) measurements have been developed in literature to locate a target node with the help of anchors (nodes with known positions). They require to select a reference anchor in order to cancel nuisance parameters or relax stringent synchronization requirements, and suffer from a poor reference selection. We propose reference-free localization estimators based on TOA measurements to decouple the reference dependency. Furthermore, we generalize existing reference-based closed-form localization estimators using TOA or TDOA measurements, and shed new light on their relations to clarify some confusions that still persist in recent literature. Robust time-based localization: Time-based localization approaches attract a lot of interest due to their high accuracy and potentially low cost for WSNs. However, time-based localization is tightly coupled with clock synchronization. Thus, the reliability of timestamps in time-based localization becomes an important yet challenging task to deal with. Regardless of the reliability of the timestamps from the target node, we propose a novel ranging protocol, namely asymmetric trip ranging (ATR), which leads to localization methods that are naturally immune to internal attacks mounted by a compromised target node. Robust localization strategies using the ATR protocol based on TOA measurements are proposed to localize a target node with the help of anchors for asynchronous networks. Kalman tracking: Due to the nonlinearity of the localization problem, a Kalman filter (KF) is usually replaced by an extended KF (EKF) for tracking a mobile target. However, the modeling errors inherently contained in the EKF degrade the tracking performance. Therefore, we make use of the ATR protocol again, carry out exact linearizations, and achieve a KF based on a linear measurement model to track a mobile target with the aid of fixed anchors.","wireless sensor networks (WSN); ultrawide band (UWB); transmitted-reference (TR) UWB; time-of-arrival (TOA); synchronization; localization; kalman filter (KF)","en","doctoral thesis","","","","","","","","2011-12-02","Electrical Engineering, Mathematics and Computer Science","Microelectronics & Computer Engineering","","","",""
"uuid:f23c1942-2204-46db-b9a5-6d167056af4b","http://resolver.tudelft.nl/uuid:f23c1942-2204-46db-b9a5-6d167056af4b","Eco-morphological problems in the Yangtze estuary and the Western Scheldt","De Vriend, H.J.; Wang, Z.B.; Ysebaert, T.; Herman, P.M.J.; Ding, P.","","2011","This paper compares the Yangtze Estuary in China and the Western Scheldt Estuary in The Netherlands by their morphodynamic and ecological systems, their engineering works and estuarine management issues, and the major challenges in studying them. Physically speaking, the two estuaries are very different. The Yangtze Estuary is much larger and much more influenced by the upstream river than the Western Scheldt. Yet, they also have a number of morphological and ecological features in common. Both estuaries have a multi-channel system and extensive intertidal flats and wetlands with ecologically valuable flora and fauna. These eco-morphological systems are influenced by similar societal developments and human activities. Examples of the latter are engineering works and dredging activities for improving and maintaining the navigation channels, and shoreline management activities including land reclamations and setbacks. The fundamental eco-morphological phenomena that remain to be analysed and understood are the same for the two estuaries and will be discussed in this paper.","eco-geomorphology; human activities; management issues; research problems","en","journal article","Springer/Society of Wetland Scientists","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:9c25390b-0a24-4672-b11f-47c4c79731ef","http://resolver.tudelft.nl/uuid:9c25390b-0a24-4672-b11f-47c4c79731ef","Assortativity of complementary graphs","Wang, H.; Winterbach, W.; Van Mieghem, P.F.A.","","2011","","","en","journal article","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Telecommunications","","","",""
"uuid:77148673-1e07-44c7-86de-60ce2fbd4f40","http://resolver.tudelft.nl/uuid:77148673-1e07-44c7-86de-60ce2fbd4f40","Development of tidal watersheds in the Wadden Sea","Wang, Z.B.; Vroom, J.; van Prooijen, B.C.; Labeur, R.J.; Stive, M.J.F.; Hansen, M.H.P.","","2011","The Wadden Sea consists of a series of tidal lagoons which are connected to the North Sea by tidal inlets. Boundaries to each lagoon are the mainland coast, the barrier islands on both sides of the tidal inlet, and the tidal watersheds behind the two barrier islands. Behind each Wadden Island there is a tidal watershed separating two adjacent tidal lagoons. The locations of the tidal watersheds in the Wadden Sea are not fixed. Especially after a human interference in one of the tidal lagoons, a tidal watershed can move and thereby influence the distribution of area between the lagoons. This appears to be important for the morphological development in not only the basin in which the interference takes place, but also in the adjacent basins. This paper describes theoretical analyses and numerical modelling aimed at improving the insights into the location of the tidal watersheds, their movements, and the impact of the movements of tidal watersheds on the morphological development of a multi-basin system like the Wadden Sea.","","en","conference paper","Tsinghua University Press","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:ed5c8fa4-1c0a-4976-b646-1aaf9a7fa5bf","http://resolver.tudelft.nl/uuid:ed5c8fa4-1c0a-4976-b646-1aaf9a7fa5bf","Crystal fields, disorder, and antiferromagnetic short-range order in Yb0.24Sn0.76Ru","Klimczuk, T.; Wang, C.H.; Lawrence, J.M.; Xu, Q.; Durakiewicz, T.; Ronning, F.; Llobet, A.; Trouw, F.; Kurita, N.; Tokiwa, Y.; Lee, H.; Booth, C.H.; Gardner, J.S.; Bauer, E.D.; Joyce, J.J.; Zandbergen, H.W.; Movshovich, R.; Cava, R.J.; Thompson, J.D.","","2011","We report extensive measurements on a new compound (Yb0.24Sn0.76)Ru that crystallizes in the cubic CsCl structure. Valence-band photoemission (PES) and L3 x-ray absorption show no divalent component in the 4f configuration of Yb. Inelastic neutron scattering (INS) indicates that the eight-fold degenerate J-multiplet of Yb3+ is split by the crystalline electric field (CEF) into a ?7-doublet ground state and a ?8 quartet at an excitation energy 20 meV. The magnetic susceptibility can be fit very well by this CEF scheme under the assumption that a ?6-excited state resides at 32 meV; however, the ?8/?6 transition expected at 12 meV was not observed in the INS. The resistivity follows a Bloch-Grüneisen law shunted by a parallel resistor, as is typical of systems subject to phonon scattering with no apparent magnetic scattering. All of these properties can be understood as representing simple local moment behavior of the trivalent Yb ion. At 1 K there is a peak in specific heat that is too broad to represent a magnetic-phase transition, consistent with absence of magnetic reflections in neutron diffraction. On the other hand this peak also is too narrow to represent the Kondo effect in the ?7-doublet ground state. On the basis of the field dependence of the specific heat, we argue that antiferromagnetic (AF) short-range order (SRO) (possibly coexisting with Kondo physics) occurs at low temperatures. The long-range magnetic order is suppressed because the Yb site occupancy is below the percolation threshold for this disordered compound.","","en","journal article","American Physical Society","","","","","","","","Applied Sciences","QN/Quantum Nanoscience","","","",""
"uuid:aef95560-b82b-43bc-8a6d-df8c13c3b51b","http://resolver.tudelft.nl/uuid:aef95560-b82b-43bc-8a6d-df8c13c3b51b","Thermal conductivity of microPCMs-filled epoxy matrix composites","Su, J.F.; Wang, X.Y; Huang, Z.; Zhao, Y.H.; Yuan, X.Y.","","2011","Microencapsulated phase change materials (microPCMs) have been widely applied in solid matrix as thermal-storage or temperature-controlling functional composites. The thermal conductivity of these microPCMs/matrix composites is an important property need to be considered. In this study, a series of microPCMs have been fabricated using the in situ polymerization with various core/shell ratio and average diameter; the thermal conductivity of microPCMs/epoxy composites were investigated in details. The results show that the microPCMs have smooth surface and regular global shape with compact methanol–melamine–formaldehyde shell. The shell thickness does not greatly influence the phase change behaviors of PCM. Moreover, smaller microPCMs embedded in epoxy can improve the thermal transmission ability of composites. The effect of thermal conductivity of composites can be improved with higher volume fraction (10–30%) of microPCMs; and smaller size microPCMs with the same content of PCM may also enhance the thermal transmission area in matrix. Modeling analysis of relative thermal conductivity indicates that mixing higher thermal conductivity additive in PCM or matrix is an appropriate method to improve the thermal conductivity of microPCMs/matrix composites.","microcapsules; phase change materials; thermal conductivity; epoxy; composites","en","journal article","Springer-Verlag","","","","","","","","Civil Engineering and Geosciences","Design and Construction","","","",""
"uuid:46dedfa7-d6e7-4f29-88f7-a7ea0a8b87d1","http://resolver.tudelft.nl/uuid:46dedfa7-d6e7-4f29-88f7-a7ea0a8b87d1","Decreasing the spectral radius of a graph by link removals","Van Mieghem, P.; Stevanovi?, D.; Kuipers, F.; Li, C.; Van de Bovenkamp, R.; Liu, D.; Wang, H.","","2011","The decrease of the spectral radius, an important characterizer of network dynamics, by removing links is investigated. The minimization of the spectral radius by removing m links is shown to be an NP-complete problem, which suggests considering heuristic strategies. Several greedy strategies are compared, and several bounds on the decrease of the spectral radius are derived. The strategy that removes that link l=i~j with largest product (x1)i(x1)j of the components of the eigenvector x1 belonging to the largest adjacency eigenvalue is shown to be superior to other strategies in most cases. Furthermore, a scaling law where the decrease in spectral radius is inversely proportional to the number of nodes N in the graph is deduced. Another sublinear scaling law of the decrease in spectral radius versus the number m of removed links is conjectured.","","en","journal article","American Physical Society","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Telecommunications","","","",""
"uuid:65f08ff0-2d17-4d2f-90b6-6c9f604da427","http://resolver.tudelft.nl/uuid:65f08ff0-2d17-4d2f-90b6-6c9f604da427","The Improvement of Oxidation Resistance of a Re-Based Diffusion Barrier/Ni–Al Coating on the Single-Crystal Ni-Based TMS-82+ Superalloy","Wu, Y.; Wang, Y.M.; Song, G.M.; Li, X.W.","","2011","Oxidation behavior of a Re-based diffusion barrier/Ni–Al coated single-crystal (SC) Ni-based TMS-82+ superalloy was studied to compare with those of the base and Ni–Al coated superalloys under cyclic air at 1150 °C for 200 h. The base superalloy showed a negative mass gain due to extensive oxide spallation, and the Ni–Al coated superalloy without the diffusion barrier started to spall slightly after about 90 h. The oxidation resistance of the Ni–Al coated superalloy with the Re-based diffusion barrier was greatly improved due to the formation of a dense ?-Al2O3 layer in the scale. The Re-based alloy was an effective diffusion barrier layer against inward diffusion of Al and outward diffusion of alloying elements in the alloy substrate due to the reduced thickness of interdiffusion zone with small amount of detrimental precipitates and higher content of Al in the Ni–Al coating that supplied enough Al for formation of the ?-Al2O3 layer.","single-crystal Ni-based superalloy; diffusion barrier; coating; oxidation; microstructure; electron probe microanalysis (EPMA)","en","journal article","Springer","","","","","","","","Mechanical, Maritime and Materials Engineering","Materials Science and Engineering","","","",""
"uuid:84b18a44-2736-4e6d-8e9f-53338ccb0259","http://resolver.tudelft.nl/uuid:84b18a44-2736-4e6d-8e9f-53338ccb0259","The agent-construction system for procuring mega projects in China","Lu, W.; Liu, A.; Wang, H.; Wu, Z.","","2011","While heated discussions have been directed towards various innovative procurement systems such as PPP, PFI, and BOT that carry the great expectation to help materialise the projects and deliver value to the society, a procurement system named agent-construction system (ACS or in Chinese Dai Jian Zhi) is being prevailing in Chinas public procurement. This research aims to examine ACS by relating them to Chinas particular Political, Economics, Social, Technological, Environmental, and Legal (PESTEL) background. It is found that the ACS is promising in procuring public projects owing to two merits: (a) clearly defined right and responsibilities; and (b) appropriate allocation of resources and risks amongst parties involved. The research is particularly useful when governments worldwide are searching for innovative procurement approaches to help deliver public projects and services. It also sheds light on how to devise an innovative procurement system. A word of caution, nevertheless, is that readers should not follow this good practice slavishly. One ought to truly understand the essence of procurement innovation and devise suitable innovative procurement systems in a given PESTEL setting.","procurement innovation; Agent-Construction-System; construction procurement; China","en","conference paper","","","","","","","","","","","","","",""
"uuid:8b9642e5-bc6f-4ad0-a413-fa5f505cc2ad","http://resolver.tudelft.nl/uuid:8b9642e5-bc6f-4ad0-a413-fa5f505cc2ad","Reconfigurable digital receiver design and application for instantaneous polarimetric measurement","Wang, Z.; Krasnov, O.A.; Babur, G.P.; Ligthart, L.P.; Van der Zwan, F.","","2011","This paper presents the development of a reconfigurable receiver to undertake challenging signal processing tasks for a novel polarimetric radar system. The field-programmable gate arrays (FPGAs)-based digital receiver samples incoming signals at intermediate frequency (IF) and processes signals digitally instead of using conventional analog approaches. It offers more robust system stability and avoids unnecessary multichannel calibrations of analog circuits for a full polarimetric radar. Two kinds of dual-orthogonal signals together with corresponding processing algorithms have been investigated; the digital implementation architectures for all algorithms are then presented. Processing algorithms implemented in FPGA chips can be reconfigured adaptively regarding to different transmitted waveforms without modification of hardware. The successful development of such reconfigurable receiver extends our radar capacity and thus yields tremendous experimental flexibility for atmospheric remote sensing and polarimetric studies of ground-based targets.","radar signal processing and system modeling; radar architecture and systems","en","journal article","Cambridge University Press","","","","","","","2012-04-06","Electrical Engineering, Mathematics and Computer Science","International Research Centre for Telecommunications and Radar, IRCTR","","","",""
"uuid:68108b2e-f488-4695-88ae-2d521c31d490","http://resolver.tudelft.nl/uuid:68108b2e-f488-4695-88ae-2d521c31d490","Evaluating GOCE data near a mid-ocean ridge and possible application to crustal structure in Scandinavia","Van der Wal, W.; Wang, L.; Visser, P.N.A.M.; Sneeuw, N.; Vermeersen, L.L.A.","","2011","GOCE gravity fields are assessed in an area around Reykjanes Ridge. Ship gravity measurements were found to be to inaccurate to determine possible improvement of GOCE gravity field models compared to the best available GRACE gravity field model. Differences between the GOCE gravity field models and EGM2008 does not appear to contain a component of the mid-ocean ridge signal. However the differences follow the Greenland coastline, which could indicate small errors in EGM 2008 there as a result of piecing together different gravity field observations. A Butterworth bandpass filter was applied to gradiometer observations at orbit height. After filtering, differences between repeat tracks with a magnitude of tens of mE are present, which can not be explained by position or attitude of the satellite. In order to reach the repeatability that can be expected from GOCE measurements, filtering methods need to improve. It was found that differences between global GRACE and GOCE gravity field models are small compared to uncertainty in crustal and upper mantle structure. Thus, geophysical inversion studies should focus on the gravity gradient observations in the instrument reference frame and at orbit height.","","en","conference paper","European Space Agency (ESA)","","","","","","","","Aerospace Engineering","Space Engineering","","","",""
"uuid:f18f62c2-cbf3-403b-8f62-8ffc23602132","http://resolver.tudelft.nl/uuid:f18f62c2-cbf3-403b-8f62-8ffc23602132","Interference management in wireless communication systems: Theory and applications","Xin, Y.; Wang, X.; Leus, G.; Yue, G.; Jiang, J.","","2011","","","en","journal article","Hindawi Publishing Corporation","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Microelectronics & Computer Engineering","","","",""
"uuid:60845740-f79f-44f7-a918-a8939b86ab17","http://resolver.tudelft.nl/uuid:60845740-f79f-44f7-a918-a8939b86ab17","Distribution and Diversity of Gallionella-Like Neutrophilic Iron Oxidizers in a Tidal Freshwater Marsh","Wang, J.; Vollrath, S.; Behrends, T.; Bodelier, P.L.E.; Muyzer, G.; Meima-Franke, M.; Den Oudsten, F.; Van Cappellen, P.; Laanbroek, H.J.","","2011","Microbial iron oxidation is an integral part of the iron redox cycle in wetlands. Nonetheless, relatively little is known about the composition and ecology of iron-oxidizing communities in the soils and sediments of wetlands. In this study, sediment cores were collected across a freshwater tidal marsh in order to characterize the iron-oxidizing bacteria (FeOB) and to link their distributions to the geochemical properties of the sediments. We applied recently designed 16S rRNA primers targeting Gallionella-related FeOB by using a nested PCR-denaturing gradient gel electrophoresis (DGGE) approach combined with a novel quantitative PCR (qPCR) assay. Gallionella-related FeOB were detected in most of the samples. The diversity and abundance of the putative FeOB were generally higher in the upper 5 to 12 cm of sediment than in deeper sediment and higher in samples collected in April than in those collected in July and October. Oxygen supply by macrofauna appears to be a major force in controlling the spatial and temporal variations in FeOB communities. The higher abundance of Gallionella-related FeOB in April coincided with elevated concentrations of extractable Fe(III) in the sediments. Despite this coincidence, the distributions of FeOB did not exhibit a simple relationship to the redox zonation inferred from the geochemical depth profiles.","","en","journal article","American Society for Microbiology","","","","","","","","Applied Sciences","Biotechnology","","","",""
"uuid:21fb76c9-930e-473a-a906-013537d5a5c0","http://resolver.tudelft.nl/uuid:21fb76c9-930e-473a-a906-013537d5a5c0","River Engineering","de Vriend, H.J.; Havinga, H.; van Prooijen, B.C.; Visser, P.J.; Wang, Z.B.","","2011","In this syllabus an overview is given of the basic knowledge, which is required to prepare interventions in rivers and to estimate the consequences of these interventions. The utilization of the river for human purposes and the knowledge of hydraulics, sediment transport and morphology will be treated. At the end of this syllabus some practice examples are discussed, of which a few are focused on the Dutch section of the Rhine River.","","en","lecture notes","TU Delft, Department Hydraulic Engineering","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:43406474-0a55-496a-82bc-79cad9139d8a","http://resolver.tudelft.nl/uuid:43406474-0a55-496a-82bc-79cad9139d8a","Rivierwaterbouwkunde","de Vriend, H.J.; Havinga, H.; van Prooijen, B.C.; Visser, P.J.; Wang, Z.B.","","2011","Deze syllabus beoogt een overzicht te geven van de basiskennis die nodig is om ingrepen in de rivier voor te bereiden en de gevolgen ervan te kunnen inschatten. Er wordt ingegaan op het gebruik dat de mens maakt van de rivier en op de kennis van de hydraulica, het sedimenttransport en de morfologie. Aan het einde van het dictaat worden praktijkvoorbeelden behandeld, waarvan een aantal is geënt op het Nederlandse deel van de Rijn.","","nl","lecture notes","TU Delft, Department Hydraulic Engineering","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:de356602-9c47-49b1-91d0-581f011cd617","http://resolver.tudelft.nl/uuid:de356602-9c47-49b1-91d0-581f011cd617","Decreasing the spectral radius of a graph by link removals","Van Mieghem, P.F.A. (TU Delft Network Architectures and Services); Stevanovic, D (External organisation); Kuipers, F.A. (TU Delft Network Architectures and Services); Li, C. (TU Delft Network Architectures and Services); van de Bovenkamp, R. (TU Delft Network Architectures and Services); Liu, D. (TU Delft Network Architectures and Services); Wang, H. (TU Delft Network Architectures and Services)","","2011","","","en","journal article","","","","","","","","","","","Network Architectures and Services","","",""
"uuid:11c9b836-cb06-4e5d-a5b5-0be9421896b5","http://resolver.tudelft.nl/uuid:11c9b836-cb06-4e5d-a5b5-0be9421896b5","Design and implementation of cross-channel interference suppression for polarimetric LFM-CW radar","Babur, G.; Wang, Z.; Krasnov, O.A.; Ligthart, L.P.","","2010","This paper presents design and practical implementation of the method for cross-channel interference suppression in polarimetric LFM-CW radar with dual-orthogonal sounding signals. Simultaneously transmitted and received signals have limited orthogonality, what results in the interfering signals in the processing channels of the radar receiver. The suppression of the interfering signals is implemented in real time, characterized by simplicity and low increase of computational resources. The efficiency of the cross-channel interference suppression is demonstrated experimentally.","PARSAX; polarimetric radar; cross-channel interference suppression","en","conference paper","SPIE","","","","","","","","Electrical Engineering, Mathematics and Computer Science","International Research Centre for Telecommunication and Radar","","","",""
"uuid:184d1254-2bb2-4205-818e-7824de728c59","http://resolver.tudelft.nl/uuid:184d1254-2bb2-4205-818e-7824de728c59","Correlating the topology of a metabolic network with its growth capacity","Winterbach, W.; Wang, H.; Reinders, M.; Van Mieghem, P.; De Ridder, D.","","2010","","","en","conference paper","ICST","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Network Architectures & Services (NAS)","","","",""
"uuid:a5e4ab47-eed4-4180-b346-da086e826a02","http://resolver.tudelft.nl/uuid:a5e4ab47-eed4-4180-b346-da086e826a02","Metabolic network destruction: Relating topology to robustness","Winterbach, W.; Wang, H.; Reinders, M.; Van Mieghem, P.; De Ridder, D.","","2010","Biological networks exhibit intriguing topological properties such as small-worldness. In this paper, we investigate whether the topology of a metabolic network is related to its robustness. We do so by perturbing a metabolic system in silico, one reaction at a time and studying the correlations between growth, as predicted by flux balance analysis, and a number of topological metrics, as computed from three network representations of the metabolic system. We find that a small number of metrics correlate with growth and that only one of the network representations stands out in terms of correlated metrics. The most correlated metrics point to the importance of hub nodes in this network: so-called ""currency metabolites"". Since they are responsible for interconnecting distant functional modules in the network, they are important points in the networks for predicting if reaction removal affects growth. Source code and data are available upon request.","metabolic networks; ux balance analysis; network topology; robustness","en","conference paper","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Network Architectures and Services","","","",""
"uuid:dcbcdf5f-2992-48b9-b764-423199a27345","http://resolver.tudelft.nl/uuid:dcbcdf5f-2992-48b9-b764-423199a27345","To know or not to know: Epistemic approaches to security protocol verification","Dechesne, F.; Wang, Y.","","2010","Security properties naturally combine temporal aspects of protocols with aspects of knowledge of the agents. Since BAN-logic, there have been several initiatives and attempts to incorporate epistemics into the analysis of security protocols. In this paper, we give an overview of work in the field and present it in a unified perspective, with comparisons on technical subtleties that have been employed in different approaches. Also, we study to which degree the use of epistemics is essential for the analysis of security protocols. We look for formal conditions under which knowledge modalities can bring extra expressive power to pure temporal languages. On the other hand, we discuss the cost of the epistemic operators in terms of model checking complexity.","security protocols; dynamic epistemic logic; epistemic temporal logic; interpreted systems; verification","en","journal article","Springer","","","","","","","","Technology, Policy and Management","Infrastructures, Systems and Services","","","",""
"uuid:7a767b6d-d235-460f-aec2-2c3013634da9","http://resolver.tudelft.nl/uuid:7a767b6d-d235-460f-aec2-2c3013634da9","Spectral graph analysis of modularity and assortativity","Van Mieghem, P.F.A.; Ge, X.; Schumm, P.; Trajanovski, S.; Wang, H.","","2010","Expressions and bounds for Newman’s modularity are presented. These results reveal conditions for or properties of the maximum modularity of a network. The influence of the spectrum of the modularity matrix on the maximum modularity is discussed. The second part of the paper investigates how the maximum modularity, the number of clusters, and the hop count of the shortest paths vary when the assortativity of the graph is changed via degree-preserving rewiring. Via simulations, we show that the maximum modularity increases, the number of clusters decreases, and the average hop count and the effective graph resistance increase with increasing assortativity.","","en","journal article","American Physical Society","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Telecommunications","","","",""
"uuid:95de5d03-4442-4166-83b6-5b429a08a136","http://resolver.tudelft.nl/uuid:95de5d03-4442-4166-83b6-5b429a08a136","Regional governance, innovation and low carbon transitions: Exploring the case of Wales","Wang, Y.; Eames, M.","","2010","With the rapid development of its iron and coal industries, by the mid-18th Century South Wales arguably emerged as the worlds first carbon-based economy. Since the mid-20th century landscape changes, associated with: i) energy regime shifts from coal to oil and gas; and ii) globalisation and neo-liberalism have combined to drive the equally rapid deindustrialization of the Welsh economy: a process which has left a structural legacy of economic and social deprivation across much of the region. In this context devolution and the establishment of a Welsh Assembly Government (WAG) with a statutory duty to promote sustainable development, has presented both unique opportunities and challenges. Despite limited powers WAG is determined that Wales will play an internationally leading role in tackling climate change. Rather than simply acting as a policy taker, WAG has established ambitious targets which exceed current UK and international commitments: including a 3% annual reduction in GGE in areas of devolved competence; all new buildings to be zero carbon; and to produce as much electricity from renewable sources as is consumed in Wales by 2025. This paper will explore the politics of sustainable regions through the governance of energy and innovation in Wales. Particular attention will be paid to: i) insights from past transitions; ii) the economic and political context of devolution; iii) the emergence of a distinctive Welsh transition narrative; iv) and the role of innovation in the built environment, and associated regional innovation systems, not only in delivering WAGs carbon reduction targets but also its social and economic objectives.","sustainable regiosn; transitions; low-carbon; innovation","en","conference paper","","","","","","","","","","","","","",""
"uuid:1c323986-1b97-4eb8-9b88-0630ee7876a5","http://resolver.tudelft.nl/uuid:1c323986-1b97-4eb8-9b88-0630ee7876a5","Emergence of modular structure in a large-scale brain network with interactions between dynamics and connectivity","Stam, C.J.; Hillebrand, A.; Wang, H.; Van Mieghem, P.","","2010","A network of 32 or 64 connected neural masses, each representing a large population of interacting excitatory and inhibitory neurons and generating an electroencephalography/magnetoencephalography like output signal, was used to demonstrate how an interaction between dynamics and connectivity might explain the emergence of complex network features, in particular modularity. Network evolution was modeled by two processes: (i) synchronization dependent plasticity (SDP) and (ii) growth dependent plasticity (GDP). In the case of SDP, connections between neural masses were strengthened when they were strongly synchronized, and were weakened when they were not. GDP was modeled as a homeostatic process with random, distance dependent outgrowth of new connections between neural masses. GDP alone resulted in stable networks with distance dependent connection strengths, typical small-world features, but no degree correlations and only weak modularity. SDP applied to random networks induced clustering, but no clear modules. Stronger modularity evolved only through an interaction of SDP and GDP, with the number and size of the modules depending on the relative strength of both processes, as well as on the size of the network. Lesioning part of the network, after a stable state was achieved, resulted in a temporary disruption of the network structure. The model gives a possible scenario to explain how modularity can arise in developing brain networks, and makes predictions about the time course of network changes during development and following acute lesions.","complex brain networks; graph theory; small-world networks; modularity; plasticity; synchronization; development; lesion","en","journal article","Frontiers Research Foundation","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Network Architectures & Services (NAS)","","","",""
"uuid:e7ba9571-f161-46e2-9d1d-5f6e7dad0632","http://resolver.tudelft.nl/uuid:e7ba9571-f161-46e2-9d1d-5f6e7dad0632","Controls on precipitation and cloudiness in simulations of trade?wind cumulus as observed during RICO","VanZanten, M.C.; Stevens, B.; Nuijens, L.; Siebesma, A.P.; Ackerman, A.; Burnet, F.; Cheng, A.; Couvreux, F.; Jiang, H.; Khairoutdinov, M.; Kogan, Y.; Lewellen, D.C.; Mechem, D.; Nakamura, K.; Noda, A.; Shipway, B.J.; Slawinska, J.; Wang, S.; Wyszogrodzki, A.","","2010","Twelve large?eddy simulations, with a wide range of microphysical representations, are compared to each other and to independent measurements. The measurements and the initial and forcing data for the simulations are taken from the undisturbed period of the Rain in Cumulus over the Ocean (RICO) field study. A regional downscaling of meteorological analyses is performed so as to provide forcing data consistent with the measurements. The ensemble average of the simulations plausibly reproduces many features of the observed clouds, including the vertical structure of cloud fraction, profiles of cloud and rain water, and to a lesser degree the population density of rain drops. The simulations do show considerable departures from one another in the representation of the cloud microphysical structure and the ensuant surface precipitation rates, increasingly so for the more simplified microphysical models. There is a robust tendency for simulations that develop rain to produce a shallower, somewhat more stable cloud layer. Relations between cloud cover and precipitation are ambiguous.","","en","journal article","American Geophysical Union","","","","","","","","Applied Sciences","MSP/Multi-Scale Physics","","","",""
"uuid:668c6217-8360-4b81-93dd-0726b584584c","http://resolver.tudelft.nl/uuid:668c6217-8360-4b81-93dd-0726b584584c","Improvement of the Oxidation Resistance of the Single-Crystal Ni-Based TMS-82+ Superalloy by Ni–Al Coatings with/without the Diffusion Barrier","Wu, Y.; Li, X.W.; Song, G.M.; Wang, Y.M.; Narita, T.","","2010","Oxidation behavior of the uncoated base, Ni–Al coated and Re–Cr-Ni plus Ni–Al coated single-crystal (SC) Ni-based TMS-82+ superalloy is studied under cyclic air at 900ºC for 200 h to assess the oxidation resistance. Regardless of the coating processing, Ni–Al coating is effective in improving the oxidation resistance due to the formation of a continuous a-Al2O3 layer in the scale. For the uncoated base superalloy, the mass-gain curves are fitted by a subparabolic relationship, and complex oxide products including predominately NiO, some CrTaO4, a-Al2O3, Cr2O3, a minor of spinels of (Ni, Co)Al2O4, AlTaO4 and h-Al2O3 are detected. Time-dependence of the oxide growth rate for both coated superalloy with/without the diffusion barrier is explained by the parabolic relationship. The oxide scales consist predominately of a-Al2O3 and a minor of h-Al2O3. The diffusion barrier of r-phase plays a negligible effect on the oxidation resistance during the cyclic exposure environment. The amount of detrimental ý-phase and topologically close-packed (TCP) phases in the interdiffusion zone in the coated superalloy with the diffusion barrier is greatly reduced compared with that without the diffusion barrier due to the distinct barrier effect limiting diffusion of elements between the bond-coat and the substrate.","Single-crystal Ni-based superalloy; Diffusion barrier; Coating; Oxidation; Microstructure; Electron probe microanalysis (EPMA)","en","journal article","Springer Verlag","","","","","","","","Mechanical, Maritime and Materials Engineering","Materials Science and Engineering","","","",""
"uuid:d7251537-2094-4b9c-a7d7-2823f41d49f6","http://resolver.tudelft.nl/uuid:d7251537-2094-4b9c-a7d7-2823f41d49f6","Effect of tumor resection on the characteristics of functional brain networks","Wang, H.; Douw, L.; Hernández, J.M.; Reijneveld, J.C.; Stam, C.J.; Van Mieghem, P.","","2010","Brain functioning such as cognitive performance depends on the functional interactions between brain areas, namely, the functional brain networks. The functional brain networks of a group of patients with brain tumors are measured before and after tumor resection. In this work, we perform a weighted network analysis to understand the effect of neurosurgery on the characteristics of functional brain networks. Statistically significant changes in network features have been discovered in the beta (13–30 Hz) band after neurosurgery: the link weight correlation around nodes and within triangles increases which implies improvement in local efficiency of information transfer and robustness; the clustering of high link weights in a subgraph becomes stronger, which enhances the global transport capability; and the decrease in the synchronization or virus spreading threshold, revealed by the increase in the largest eigenvalue of the adjacency matrix, which suggests again the improvement of information dissemination.","","en","journal article","American Physical Society","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Telecommunications","","","",""
"uuid:39e5d1b4-b365-4797-9591-7748514bec90","http://resolver.tudelft.nl/uuid:39e5d1b4-b365-4797-9591-7748514bec90","Tuning single GaAs quantum dots in resonance with a rubidium vapor","Akopian, N.; Perinetti, U.; Wang, L.; Rastelli, A.; Schmidt, O.G.; Zwiller, V.","","2010","We study single GaAs quantum dots with optical transitions that can be brought into resonance with the widely used D2 transitions of rubidium atoms. We achieve resonance by Zeeman or Stark shifting the quantum dot levels. We discuss an energy stabilization scheme based on the absorption of quantum dot photoluminescence in a rubidium vapor. This offers a scalable means to counteract slow spectral diffusion in quantum dots.","gallium arsenide; III-V semiconductors; photoluminescence; rubidium; semiconductor quantum dots; Stark effect; Zeeman effect","en","journal article","American Institute of Physics","","","","","","","","Applied Sciences","QN/Quantum Nanoscience","","","",""
"uuid:c0cc7a55-ea5f-4235-b8fa-f87d824db2a1","http://resolver.tudelft.nl/uuid:c0cc7a55-ea5f-4235-b8fa-f87d824db2a1","Morfologische effecten van een getijdecentrale in de Brouwersdam: Concept","Wang, Z.B.","Deltares","2010","De morfologische effecten van het gedeeltelijk herstellen van het getij in het Grevelingenmeer door middel van een getijdecentrale worden geanalyseerd. De veranderingen in de morfologische ontwikkelingen die de getijdecentrale kan veroorzaken zijn geëvalueerd voor zowel binnen als buiten de Brouwersdam. Het gaat om een eerste analyse op basis van literatuur, velddata en resultaten van stromingsberekeningen met een bestaand model. Uit de analyse is geconcludeerd dat het onwaarschijnlijk is dat de werking van de getijdecentrale in gevaar zal komen door sedimentatie in de geulen. Wel zijn een aantal zorgpunten m.b.t. de effecten van de centrale geconstateerd: - Verruiming van de kortsluitgeul dicht bij de getijdecentrale aan de binnen zijde van de Brouwersdam door erosie. - Mogelijke afname in omvang van de Bollen van Ooster. - Erosie van geulen dichtbij de getijdecentrale buiten de Brouwersdam, waardoor het afgezette slib vrij kan komen. - Mogelijk heroriëntatie van geulen in het mondinggebied die gepaard gaat met bijvoorbeeld sterk lokale erosies.","Grevelingen; Brouwersdam; getijcentrale; morfologie; tidal power plant","nl","report","Deltares","","","","","","","","","","","","Grevelingen",""
"uuid:68e2702f-0ae1-4f7e-9002-9bb741277878","http://resolver.tudelft.nl/uuid:68e2702f-0ae1-4f7e-9002-9bb741277878","Influence of assortativity and degree-preserving rewiring on the spectra of networks","Van Mieghem, P.; Wang, H.; Ge, X.; Tang, S.; Kuipers, F.A.","","2010","Newman’s measure for (dis)assortativity, the linear degree correlation coefficient ?D, is reformulated in terms of the total number Nk of walks in the graph with k hops. This reformulation allows us to derive a new formula from which a degree-preserving rewiring algorithm is deduced, that, in each rewiring step, either increases or decreases ?D conform our desired objective. Spectral metrics (eigenvalues of graph-related matrices), especially, the largest eigenvalue ?1 of the adjacency matrix and the algebraic connectivity ?N?1 (second-smallest eigenvalue of the Laplacian) are powerful characterizers of dynamic processes on networks such as virus spreading and synchronization processes. We present various lower bounds for the largest eigenvalue ?1 of the adjacency matrix and we show, apart from some classes of graphs such as regular graphs or bipartite graphs, that the lower bounds for ?1 increase with ?D. A new upper bound for the algebraic connectivity ?N?1 decreases with ?D. Applying the degree-preserving rewiring algorithm to various real-world networks illustrates that (a) assortative degree-preserving rewiring increases ?1, but decreases ?N?1, even leading to disconnectivity of the networks in many disjoint clusters and that (b) disassortative degree-preserving rewiring decreases ?1, but increases the algebraic connectivity, at least in the initial rewirings.","","en","journal article","EDP Sciences","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Telecommunications","","","",""
"uuid:4a09d4d8-9152-40eb-8acb-13c2e02f2049","http://resolver.tudelft.nl/uuid:4a09d4d8-9152-40eb-8acb-13c2e02f2049","Morphological development of the rif and the Engelsmanplaat: An intertidal flat complex in the Frisian inlet, Dutch Wadden Sea","Wang, Z.B.; Oost, A.P.","","2010","The Rif and the Engelsmanplaat form together a supra- to intertidal flat-complex at the fringe of the ebb-tidal delta and the back barrier area in the Frisian Inlet, located between the Dutch Wadden Sea Islands Ameland and Schiermonnikoog. The complex divides the Frisian Inlet into the Pinkegat Inlet in the west and the Zoutkamperlaag Inlet in the east. During the last decades the Engelsmanplaat has been suffering from serious erosion. This paper presents a study meant to find the causes for the recent erosion, especially to answer the question if the erosion is related to the human interferences in the area. The study is based on literature survey, data analysis and modelling of hydrodynamic processes. It is concluded that the recent erosion fits into the pseudo-cyclic development of the intertidal flat complex. However, the period of erosion may have been longer than normal and the rate of erosion may have been higher than normal. It is also concluded that such abnormal development is probably effects of the closure of the Lauwerszee in 1969 and not due to land subsidence caused by gas mining.","intertidal flats; Wadden Sea; land subsidence; closure; morphology; long-term development","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:db31899c-ca91-47a1-879e-4f4fa1d004e8","http://resolver.tudelft.nl/uuid:db31899c-ca91-47a1-879e-4f4fa1d004e8","A process-based approach to sediment transport in the Yangtze estuary","Chu, A.; Wang, Z.B.; De Vriend, H.J.; Stive, M.J.F.","","2010","A process-based model for the Yangtze Estuary is constructed to study the sediment transport in the estuary. The proposed model covers the entire tidal region of the estuary, the Hangzhou Bay and a large part of the adjacent sea. The dominant processes, fluvial and tidal, are included in the model. The calibration of the model against extensive flow, water level, salinity and suspended sediment data shows a good representation of observed phenomena. With the present calibrated and validated model, the residual flow field and the residual sediment transport field are obtained. The residual sediment transport pattern gives insight into the morphological behaviour of the mouth bars.","Yangtze Estuary; mouth bar; morphology; sediment transport; process-based model","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:cb32eba2-0207-4ea2-855c-2047fd8fbaaa","http://resolver.tudelft.nl/uuid:cb32eba2-0207-4ea2-855c-2047fd8fbaaa","Graphs with given diameter maximizing the algebraic connectivity","Wang, H.; Kooij, R.E.; Van Mieghem, P.","","2010","We propose a class of graphs G?D(n1, n2, ..., nD+1), containing of a chain of D+1 cliques Kn1 , Kn2 , ..., KnD+1, where neighboring cliques are fully-interconnected. The class of graphs has diameter D and size N = ? 1?i?D+1ni. We prove that this class of graphs can achieve the maximal number of links, the minimum average hopcount, and more interestingly, the maximal of any Laplacian eigenvalue among all graphs with N nodes and diameter D. The algebraic connectivity is the eigenvalue of the Laplacian that has been studied most, because it features many interesting properties. We determine the graph with the largest algebraic connectivity among graphs with N nodes and diameter D ? 4. For other diameters, numerically searching for the maximum of any eigenvalue is feasible, because (a) the searching space within the class G?D(n1, n2, ..., nD+1) is much smaller than within all graphs with N nodes and diameter D; (b) we reduce the calculation of the Laplacian spectrum from a N × N to a (D +1)× (D + 1) matrix. The maximum of any Laplacian eigenvalue obtained either theoretically or by numerical searching is applied to (1) investigate the topological features of graphs that maximize different Laplacian eigenvalues; (2) study the correlation between the maximum algebraic connectivity amax(N, D) and N as well as D and (3) evaluate two upper bounds of the algebraic connectivity that are proposed in the literature.","graphs; algebraic connectivity; maximize; diameter","en","journal article","Elsevier","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Network Architectures & Services (NAS)","","","",""
"uuid:4876523e-5333-4126-9d30-76d5eabe45db","http://resolver.tudelft.nl/uuid:4876523e-5333-4126-9d30-76d5eabe45db","Basics and first experiments demonstrating isolation improvements in the agile polarimetric FM-CW radar – PARSAX","Krasnov, O.A.; Babur, G.P.; Wang, Z.; Ligthart, L.P.; Van der Zwan, F.","","2010","The article describes the IRCTR PARSAX radar system, the S-band high-resolution Doppler polarimetric frequency modulated continuous wave (FM-CW) radar with dual-orthogonal sounding signals, which has the possibility to measure all elements of the radar target polarization scattering matrix simultaneously, in one sweep. The performance of such radar depends of the level of sounding signals orthogonality. In the main operational mode, the radar will be used for atmospheric remote sensing and polarimetric studies of ground-based targets. In such mode it will use a pair of synchronous linearly- frequency modulated (LFM) continuous signals with opposite frequency excursions of 50 MHz and duration of 1 ms. Such a combination of sounding signals has limited orthogonality even for huge BT-products, which produce cross-channel interferences. These interferences in case of radar scene with multiple pointed and distributed targets can completely degrade radar operational performance. In this article, we propose simple and effective technique to suppress interferences and to restore radar performance. The technique has been tested using simulation and has been implemented in multi-channel digital receiver of the PARSAX radar. The real radar measurements presented to illustrate effectiveness of cross-channel interferences suppression. The proposed technique can be useful not only for polarimetric radar design, but also in much wide radar applications, which use waveforms with high orthogonality.","polarimetric radar; FM-CW radar; LFM; orthogonal waveforms","en","journal article","Cambridge University Press","","","","","","","","Electrical Engineering, Mathematics and Computer Science","International Research Centre for Telecommunications and Radar, IRCTR","","","",""
"uuid:7d5376aa-597b-4c51-bd31-477dff682218","http://resolver.tudelft.nl/uuid:7d5376aa-597b-4c51-bd31-477dff682218","Networking Technologies for Future Home Networks Using 60 GHz Radio","Wang, J.","Niemegeers, I.G.M.M. (promotor)","2010","Networking technologies have been changing the life of people in their private residential space. With the arrival of high definition (HD) multimedia services and broadband communications into the living space, future home networks are expected to support high speed device-to-device connectivity with Quality-of-Service (QoS) provisioning. There is no prize for guessing that it has to be wireless communication which creates maximal freedom. Nevertheless, it is doubtful that today's home networking technologies can sufficiently lead to the expected future of HD multimedia. Especially the maximum data rate and QoS that the network is expected to deliver have being pushed to the limits, which leads to users experience far from satisfying. In response to the critical throughput demands, the 60 GHz radio technology presents itself as an ideal solution for short-range Gbps speed indoor communication. However, from the networking point of view, the transmission range limitation and high line-of-sight (LOS) dependency are impediments for reliable connectivity at 60GHz. This leads us to critically examine current networking architecture (Chapter 3) and propose newer ones. We proposed two types of communication infrastructure with emphasis on deployment and capacity to overcome the range limitation of 60 GHz radio. The cell based infrastructure employs the radio-over-fiber (ROF) technique and brings great exibility for integrating 60 GHz radio into a multi-radio home networking environment. The ad hoc infrastructure creates a strictly wireless home networking environment, which provides maximum freedom in terms of usability. Further to resolve the dilemma of the increased network complexity and higher expectation of users on the quality of experience, we proposed functional network architecture focusing introducing ""Cognitive Plane"". It is expected to help in realizing more advanced control and management functions for enhancing service provisioning and ultimately usability of a home network to meet the expectations of users. The network architecture has sought to provide the fundamental communication means to provide in-home device-to-device 60 GHz connectivity. It leads us further towards the network protocol issues to provide reliable end-to-end connectivity with QoS. However, before setting out on specific solutions, it is of great importance to understand the features of the 60 GHz radio link in the home environment. First, we built a link stability model to understand the influence of a single link on LOS dependency under different channel conditions, antenna configurations and movement patterns of people (Chapter 4). Further to understand the performance starting from single hop to multiple hops, we studied the IEEE 802.15.3 MAC protocol and extended it to enable connectivity on the proposed ad hoc communication infrastructure (Chapter 5). To offset the influence of LOS dependency we further studied the potential use of multiple paths (Chapter 6). We proposed a cross-layer approach for assessing the multipath capacity with regard to high quality video transport. We also used the possible video coding techniques for video source and evaluating traffic allocation schemes for their abilities to make use of the capacity of multiple paths. In the cell based communication infrastructure, which is designed to support multiple radio systems, the dip in signal strength due to blocking of a 60 GHz link can be alleviated by vertical handover of a communication session to another radio to maintain the continuity of the session. However, neither the residential users nor the third party are practically able to manage such network operations in such a detail. The irregular blocking due to the presence of people throws a further challenge - solving the incertitude during handover. With the help of Artificial Intelligence (AI) based cognitive techniques, we investigated two decision making approaches utilizing Decision Theory (DT) and Markov Decision Process (MDP) (Chapter 7). Both of them are able to take into account multiple factors to make decisions in uncertain situations based on an evaluation of the candidate actions, but with different time horizons. The techniques within the cognitive networking framework can help in establishing reliable connection and application provisioning adaptively. The communication sessions are transported seamlessly without the intervention of users. Cognitive network is considered as one of the most distinguishing features of a future-proof home networking paradigm. Therefore, we looked into the proposed cognitive plane with special focus on provisioning location context information (Chapter 8). The 60 GHz radio LOS is largely influenced by the movement of people around, network devices and surrounding objects such as furniture and partitions. Thus awareness of location sustains important functionalities such as optimal radio and route selection, session transfer, self-organization and maintenance of the network etc. We designed and demonstrated an indoor positioning system using wireless sensor network as an important auxiliary component in the design of cognitive home network architecture of the future. In this dissertation we concentrated on investigating the feasible networking technologies for future homes supporting high quality high data rate multimedia services. At the same time, we are seeking approaches for embracing cognitive networks in the home network domain to assure a better user experience. Our contributions in this dissertation are in the right direction for future-proof inhome networks, by addressing both radio and network, from both architectural and protocol perspectives.","60 GHz radio; Home network","en","doctoral thesis","Ipskamp Drukkers","","","","","","","2010-06-03","Electrical Engineering, Mathematics and Computer Science","Telecommunications","","","",""
"uuid:d9b47ed2-e950-459c-8c01-7c865a12b03d","http://resolver.tudelft.nl/uuid:d9b47ed2-e950-459c-8c01-7c865a12b03d","Cloud droplet activation of mixed organic-sulfate particles produced by the photooxidation of isoprene","King, S.M.; Rosenoern, T.; Shilling, J.E.; Chen, Q.; Wang, Z.; Biskos, G.; McKinney, K.A.; Pöschl, U.; Martin, S.T.","","2010","The cloud condensation nuclei (CCN) properties of ammonium sulfate particles mixed with organic material condensed during the hydroxyl-radical-initiated photooxidation of isoprene (C5H8) were investigated in the continuous-flow Harvard Environmental Chamber. CCN activation curves were measured for organic particle mass concentrations of 0.5 to 10.0 ?g m?3, NOx concentrations from under 0.4 ppbv up to 38 ppbv, particle mobility diameters from 70 to 150 nm, and thermodenuder temperatures from 25 to 100 °C. At 25 °C, the observed CCN activation curves were accurately described by a Köhler model having two internally mixed components, namely ammonium sulfate and secondary organic material. The modeled physicochemical parameters of the organic material were equivalent to an effective hygroscopicity parameter ?ORG of 0.10±0.03, regardless of the C5H8:NOx concentration ratio for the span of >200:0.4 to 50:38 (ppbv:ppbv). The volatilization curves (i.e., plots of the residual organic volume fraction against temperature) were also similar for the span of investigated C5H8:NOx ratios, suggesting a broad similarity of particle chemical composition. This suggestion was supported by limited variance at 25 °C among the particle mass spectra. For example, the signal intensity at m/z 44 (which can result from the fragmentation of oxidized molecules believed to affect hygroscopicity and CCN properties) varied weakly from 6 to 9% across the range of investigated conditions. In contradistinction to the results for 25 °C, conditioning up to 100 °C in the thermodenuder significantly reduced CCN activity. The altered CCN activity might be explained by chemical reactions (e.g., decomposition or oligomerization) of the secondary organic material at elevated temperatures. The study's results at 25 °C, in conjunction with the results of other chamber and field studies for a diverse range of conditions, suggest that a value of 0.10±0.05 for ?ORG is representative of both anthropogenic and biogenic secondary organic material. This finding supports the use of ?ORG as a simplified yet accurate general parameter to represent the CCN activation of secondary organic material in large-scale atmospheric and climate models.","","en","journal article","Copernicus Publications","","","","","","","","Applied Sciences","ChemE/Chemical Engineering","","","",""
"uuid:894d990a-e5ea-42b0-9bcf-32f6ccae89b6","http://resolver.tudelft.nl/uuid:894d990a-e5ea-42b0-9bcf-32f6ccae89b6","Mechanical Characterization of Flexible and Stretchable Electronic Substrates","Wang, L.","Ernst, L.J. (promotor); Jansen, K.M.B. (promotor)","2010","Conventional IC packages form a rigid shell around silicon IC dies. Their purpose is to provide environmental protection, electrical interconnect and heat dissipation. Despite the fact that majority of current silicon IC?s are realized in a very thin top layer of the silicon substrate (<10µm), the typical thickness of packaged IC dies generally exceeds 150 µm. Continuous system miniaturization and performance improvement leads to new mass volume applications where packaging technology has to be reviewed. Here only the essential part of silicon IC?s i.e. the 10-20 µm thick top layer could be retained after thinning of the wafer. In the wafer thickness range of 10–30 ?m, silicon substrates become mechanically flexible and consequently offer a large field of new products and innovative applications. A promising development of flexible and stretchable substrates is proposed. 3D deformable electronics could be realized by the vertical thinning and lateral partitioning of the silicon substrate on sub-millimeter scale. The partitions or so-called segments can be combined to larger electronic systems by connecting many of these through electrical bridges. By varying the dimensions and/or the geometry of the segments and the gap size in between the segments as well as the geometry of the electrical bridges, the level of deformations can be controlled. In practical realization such patterned silicon structures have to be embedded/sandwiched into a polymer film to provide environmental protection and to prevent mechanical damage because of overstretching. In order to evaluate the influence of segment size and gap size on the occurrence of failure under bending and stretching, so-called 1st generation flexible and stretchable test samples were designed and prepared. The test samples being considered have hexagonal or square segments (varying in size from 150 to 2000 ?m) being embedded in polyimide. Special tensile and bending test tools were designed and fabricated to in situ observe the occurrence of cracks during loading. An optical microscope with the possibility of recording and analysing the digital images is used for establishing the crack density and width. Experimental and simulation results for the onset of cracking are quite disappointed. It is shown that the first cracks appear in the oxide layers in the gaps in between the silicon segments. The crack density appears to increase rapidly at early stage of loading and subsequently increases slightly. However, the width of the cracks appears to increase steadily during loading. Only at higher (mean) deformations the cracks propagate (or are generated) within the silicon itself. The onset of cracking depends significantly on the silicon segmentation size. The segment size and gap size also affects the crack density and the crack width at larger (mean) deformation levels. There is no crack detected for bending around glass cylinders (even not for the cylinder with the smallest diameter, ?= 2 mm) for samples with a square segment with 450 ?m side length and 120 ?m gap size and for samples with a hexagonal segment with 300 ?m side length and 40 ?m gap size. The remaining bending results show that for other samples with square segments failure always occurs for bending around the glass cylinder with the smallest diameter (?= 2 mm). From the tensile testing as well as from the simulation results we learned that occurrence of cracks in the oxide layers severely limits the stretchability of the substrates. Because of the early damage initiation found for the 1st generation samples, a modified design was proposed and worked out. So-called 2nd generation samples were designed and fabricated with fully segmented polycrystalline silicon segments with flexible aluminium interconnections which are supported by flexible poly-silicon support structures. Again polyimide was used as the embedding material. The samples being considered have varying segment sizes (from 150 to 450 ?m) and varying gap sizes (from 20 to 200 ?m). Various (more or less) sinusoidal interconnections were chosen with various numbers of half waves and various wave amplitudes. When the samples were bent around the (smallest) cylinder with 2 mm diameter, no damage of the segments was detected. Resistance measurements did not show a resistance increase larger than 5%. Compared to the 1st generation samples, for tensile testing of the 2nd generation samples the (mean) strain at onset of failure (which now is segment cracking) is significantly improved. In order to gain more insight into the occurrence of interconnection failures various FE simulations were performed for wave-shaped interconnections of samples with square segments (under stretching only). The local model used is made up from a single gap (of polyimide) with metallic interconnection and poly-silicon support structure in between two embedded segments. Comparison of the experimentally obtained strain values for the resistance change of 5% and the “sample mean strain” at (assumed) onset of failure, did not give a good match. Apparently the assumed onset of failure, defined by reaching the ultimate strength in the aluminium (that only occurs at some local) is not a good measure for the degradation of the electric conductivity. The “work of plastic deformation” might be better correlated to the change in resistance. The sinusoidal wave interconnection shows the best electrical performance compared to the straight interconnection and the semi-circular interconnection. The influence of wave amplitude, number of half waves and line width of the sinusoidal interconnection is explored. However, the sample mean strain at onset of interconnection failure appears to be limited to a few percents only. From both the experiments and the interconnection FE simulations it is concluded that again insufficient flexibility is obtained for all considered interconnection shapes. It is believed that this is caused by the embedding of the segments and interconnections within the polyimide. For this reason in Chapter 4 embedding in a much softer material is worked out. Also the case of a completely free interconnection (not embedded) is considered (in Chapter 5 ). In this manner a new concept of future flexible and stretchable substrates is introduced. In the concept of “Future flexible and stretchable substrates I” (Chapter 4), the segments and interconnections are fully embedded into ELASTOSIL RT 601 (a kind of silicone rubber, from now to the whole thesis, the silicone rubber is ELASTOSIL RT 601). Adequate material models for silicone rubber are essential for getting insight into the mechanical behavior of the new design through FE modeling. In particular, FE modeling is used to forecast possible failure. The mechanical properties of silicone rubber were characterized by various methods including tensile testing, cyclic tensile testing and DMA. The ultimate tensile elongation of the silicone rubber foil can reach about 176% at room temperature. Visco-elastic behaviour of the silicone rubber at room temperature is not relevant. The 3rd order Mooney model was selected for the constitutive description of the silicone rubber for the FE simulations. Based on the FE simulation results for the “future flexible and stretchable substrate I” it is expected that when increasing the mean sample strain, first the Si support structure will fail and subsequently the silicone rubber will fail during tensile loading. Failure of the Si-segments is likely not to occur at all. Compared to the 2nd generation substrates, the concept the “future flexible and stretchable substrate I” only gives an improvement of (about) a factor 2 for the main strain level at failure occurrence. The limiting factor for the improvement is the disappointing behavior of the Si-support structure. Apparently, the embedment of the Si-support structure by rubber very much reduces the “spring” behavior of the sinusoidal support structure. Therefore, a major improvement is suggested for the “Future Flexible and Stretchable Substrate II”, by not completely embedding the interconnection by silicone rubber, but only sandwiching this structure between two silicone rubber foils. For the concept of “Future Flexible and Stretchable Substrate II” the aluminum wave interconnections are replaced by copper wave interconnections because the better mechanical and electronic performance of copper. Free-standing interconnection copper lines (without support structures), sandwiched in between silicone rubber sheets, connect the Si-segments. Three types of the interconnections, meander shaped, horseshoe shaped and meshed shaped, were designed with various parameter sets. Simulations for these basic parts were performed to evaluate the influence of the geometric parameters on the flexibility and stretchability. The free-standing interconnection shapes and their geometric parameters have significant influence on the stretchability. From the three types of interconnections being considered, the meander shaped design appears to be most favourable. Compared to the results for the “Future Flexible and Stretchable Substrate I” it can be concluded that an enormous improvement of the stretchability of the interconnect structure is found. It is realized that because of the enormous flexibility of the meander shaped interconnection design, the maximum mean strain of the substrate is limited by the maximum mean strain that other parts can withstand. Here it should be noted that the maximum mean strain of the silicone rubber sheets is limited to about 176%, or less. With this elongation limit the (found) most favourable meander interconnection (W=5 ?m, R=100 ?m and ?=30 degree) will behave fully elastic and thus will not be damaged, even not under cyclic elongation.","flexible and stretchable substrate; segments; interconnection","en","doctoral thesis","","","","","","","","","Mechanical, Maritime and Materials Engineering","Precision and Microsystems Engineering","","","",""
"uuid:4209cb3e-f6eb-4f3a-a9e7-db1dc9fc0727","http://resolver.tudelft.nl/uuid:4209cb3e-f6eb-4f3a-a9e7-db1dc9fc0727","Proposal to determine the Fermi-surface topology of a doped iron-based superconductor using bulk-sensitive Fourier-transform Compton scattering","Wang, Y.J.; Lin, H.; Barbiellini, B.; Mijnarends, P.E.; Kaprzyk, S.; Markiewicz, R.S.; Bansil, A.","","2010","We have carried out first-principles calculations of the Compton scattering spectra to demonstrate that the filling of the hole Fermi surface in LaO1?xFxFeAs produces a distinct signature in the Fourier-transformed Compton spectrum when the momentum transfer vector lies along the [100] direction. We thus show how the critical concentration xc, where hole Fermi-surface pieces are filled up and the superconductivity mediated by antiferromagnetic spin fluctuations is expected to be suppressed, can be obtained in a bulk-sensitive manner.","","en","journal article","American Physical Society","","","","","","","","Applied Sciences","Radiation, Radionuclides and Reactors","","","",""
"uuid:ca45cbaa-5944-49c7-b00b-ddd19402fa67","http://resolver.tudelft.nl/uuid:ca45cbaa-5944-49c7-b00b-ddd19402fa67","Analyzing 60 GHz radio links for indoor communications","Wang, J.; Prasad, R.V.; Niemegeers, I.","","2010","With the increase in the capacity of mobile communication devices, it is but natural to expect that these devices would work ubiquitously anywhere anytime to offer high data rate support. Recently 60 GHz frequency band has been identified as an obvious choice for the high data rate indoor communications. However, as the 60 GHz radio system relies on line-of-sight (LOS) transmission for achieving Gbps data rate, the communication can be easily interrupted by obstructions breaking the LOS link, which happens often due to the movement of people in a typical indoor environment. In this paper, we define and present an analytical model for assessing link stability of 60 GHz radio for indoor wireless networks. We have developed a ray-based model to calculate the shadowing loss caused by the presence of people around the communication link while taking into account the indoor channel characteristics of 60 GHz radio and the antenna configuration. We have further considered different types of mobility of people with the ray-based model of 60 GHz link to obtain a holistic link stability model in realistic scenarios. We have given examples to show the relevance of our model and its applicability using both simulation and numerical evaluations.","60 GHz radio; link stability; line-of-sight; human body shadowing","en","journal article","IEEE","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Telecommunications","","","",""
"uuid:a70dcd65-8114-458d-b61a-5cd8d46f54eb","http://resolver.tudelft.nl/uuid:a70dcd65-8114-458d-b61a-5cd8d46f54eb","Spectral perturbation and reconstructability of complex networks","Liu, D.; Wang, H.; Van Mieghem, P.","","2010","In recent years, many network perturbation techniques, such as topological perturbations and service perturbations, were employed to study and improve the robustness of complex networks. However, there is no general way to evaluate the network robustness. In this paper, we propose a global measure for a network, the reconstructability coefficient ?, defined as the maximum number of eigenvalues that can be removed, subject to the condition that the adjacency matrix can be reconstructed exactly. Our main finding is that a linear scaling law, E[?]=aN, seems universal in that it holds for all networks that we have studied.","","en","journal article","American Physical Society","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Telecommunications","","","",""
"uuid:44af934a-eb6a-4da2-93db-95ab489dd827","http://resolver.tudelft.nl/uuid:44af934a-eb6a-4da2-93db-95ab489dd827","Quasi-static three-dimensional analysis of suction anchor mooring system","Wang, L.-Z.","","2010","","offshore","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:071e04f3-7b5c-484b-ba75-29aaef82f62c","http://resolver.tudelft.nl/uuid:071e04f3-7b5c-484b-ba75-29aaef82f62c","Interactions between fully nonlinear water waves and cylinder arrays in a wave tank","Wang, C.Z.","","2010","","hydrodynamics","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:e4023036-3c78-4d4a-ae37-3a70fd5b0d1a","http://resolver.tudelft.nl/uuid:e4023036-3c78-4d4a-ae37-3a70fd5b0d1a","Hydrodynamic forces on a rolling barge with bilge keels","Bangun, E.P.; Wang, C.M.; Utsunomiya, T.","","2010","","yachting","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:19e89859-7c67-4f52-931a-30fba16953b1","http://resolver.tudelft.nl/uuid:19e89859-7c67-4f52-931a-30fba16953b1","Influence of assortativity and degree-preserving rewiring on the spectra of networks","Van Mieghem, P.F.A. (TU Delft Network Architectures and Services); Wang, H. (TU Delft Network Architectures and Services); Ge, X (TU Delft Network Architectures and Services); Tang, S. (TU Delft Network Architectures and Services); Kuipers, F.A. (TU Delft Network Architectures and Services)","","2010","","","en","journal article","","","","","","","","","","","Network Architectures and Services","","",""
"uuid:5c4b923a-06ed-48bf-96dc-1f1ede780b9d","http://resolver.tudelft.nl/uuid:5c4b923a-06ed-48bf-96dc-1f1ede780b9d","Ranging energy optimization for robust sensor positioning based on semidefinite programming","Wang, T.; Leus, G.; Huang, L.","","2009","Sensor positioning is an important task of location-aware wireless sensor networks. In most sensor positioning systems, sensors and beacons need to emit ranging signals to each other. Sensor ranging energy should be low to prolong system lifetime, but sufficiently high to fulfill prescribed accuracy requirements. This motivates us to investigate ranging energy optimization problems. We address ranging energy optimization for an unsynchronized positioning system, which features robust sensor positioning (RSP) in the sense that a specific accuracy requirement is fulfilled within a prescribed service area. We assume a line-of-sight (LOS) channel exists between the sensor and each beacon. The positioning is implemented by time-of-arrival (TOA) based two-way ranging between a sensor and beacons, followed by a location estimation at a central processing unit. To establish a dependency between positioning accuracy and ranging energy, we assume the adopted TOA and location estimators are unbiased and attain the associated Cramer-Rao bound. The accuracy requirement has the same form as the one defined by the Federal Communication Commission (FCC), and we present two constraints with linear-matrix-inequality form for the RSP. Ranging energy optimization problems, as well as a practical algorithm based on semidefinite programming are proposed. The effectiveness of the algorithm is illustrated by numerical experiments.","CramérRao bound; localization; semidefinite programming; wireless sensor networks","en","journal article","IEEE","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Microelectronics & Computer Engineering","","","",""
"uuid:1a12b803-4e7c-4640-bc95-ca0fd575cfd6","http://resolver.tudelft.nl/uuid:1a12b803-4e7c-4640-bc95-ca0fd575cfd6","Urbanism PhD Research 2008 - 2010","Van der Hoeven, F.D.; Brand, N.; Van der Burg, L.; Çal??kan, O.; Tan, E.R.; Wang, C.Y.; Zhou, J.","Smit, M. (contributor)","2009","To ensure the quality of the Ph.D. research the Department introduced a special procedure for periodic evaluation: after a period of nine months the potential Ph.D. candidates are asked to present their research design, theoretical framework and methodological approach to the members of the Department and to an external review, drawn up by the professors of the Department and by external reviewer. Depending on the assessment of the review group, the candidates will have the opportunity to continue their research at the Department. In the mean time the (public) review sessions developed into an important element for the scientific debate of the Department. The sessions became a meeting point for the whole Department to discuss new research issues and new methodological approaches and to develop new research collaborations. In this framework the external members of the review group are playing an important role. Their critics form a mirror for the scientific standards of the Department as well as for the scientific (and social) relevancy of the research issues. With the publication of the this book we want to offer to a broader public the opportunity to deal with this debate. The different contributions are based on the papers the Ph.D. candidates prepared for the reviews and have been updatedas a result of the remarks of the peer group and the discussion during the review sessions. As a result the contributions are reflecting the ongoing efforts to redefine the discipline of urbanism under globally changing conditions. The review sessions of the department started in 2004. This book presents the results of the sessions that took place late 2007 and throughout much of 2008.","built environment; cultural heritage; housing; landscape architecture; landscape design; regional planning; spatial planning; town planning; urban design; urban development; urban planning; urban studies; urbanism","en","book","IOS Press","","","","","","","","Architecture","Urbanism","","","",""
"uuid:d0a7fc44-d22b-4574-86a9-1ad347a1ea16","http://resolver.tudelft.nl/uuid:d0a7fc44-d22b-4574-86a9-1ad347a1ea16","A CMOS Image Sensor With In-Pixel Buried-Channel Source Follower and Optimized Row Selector","Chen, Y.; Wang, X.; Mierop, A.J.; Theuwissen, A.J.P.","","2009","This paper presents a CMOS imager sensor with pinned-photodiode 4T active pixels which use in-pixel buried-channel source followers (SFs) and optimized row selectors. The test sensor has been fabricated in a 0.18-mum CMOS process. The sensor characterization was carried out successfully, and the results show that, compared with a regular imager with the standard nMOS transistor surface-mode SF, the new pixel structure reduces dark random noise by 50% and improves the output swing by almost 100% without any conflicts to the signal readout operation of the pixels. Furthermore, the new pixel structure is able to drastically minimize in-pixel random-telegraph-signal noise.","buried-channel source follower (BSF); CMOS image sensor (CIS); optimized row selector; random-telegraphsignal (RTS) noise; 4T-active-pixel sensor","en","journal article","IEEE","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Electronic Instrumentation Laboratory","","","",""
"uuid:88474bf9-2466-41cd-98f7-21cc8b51db03","http://resolver.tudelft.nl/uuid:88474bf9-2466-41cd-98f7-21cc8b51db03","Historical Morphological development of the Eastern Scheldt tidal basin (the Netherlands)","Eelkema, M.; Wang, Z.B.; Stive, M.J.F.","","2009","The Eastern Scheldt tidal basin has changed drastically in the past five centuries under the influence of both human interventions as well as extreme events. In 1530 A.D. a storm-surge inundated large parts in the landward end of the basin, and in the following four centuries local inhabitants reclaimed about as much land as was inundated in that storm. To investigate the effects of these processes on basin morphology, several different simplified geometries of the basin are used in order to gain insight into the evolution of the tidal currents over the centuries. From this model it appears that the large-scale inundations cause the basin to scour to greater depth. This in turn causes the ebb-tidal delta to grow, and causes the disappearance of the tidal watershed between the Eastern Scheldt and the Grevelingen tidal basins. Land reclamations have not been able to turn these trends around.","Tidal basin; Eastern Scheldt; Land reclamation; Inundation; Ebb-tidal delta; Tidal watershed","en","conference paper","World Scientific Publishing","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:dc5b1158-be54-42d6-a4d3-b0a19462f507","http://resolver.tudelft.nl/uuid:dc5b1158-be54-42d6-a4d3-b0a19462f507","Robustness of networks","Wang, H.","Van Mieghem, P. (promotor)","2009","Our society depends more strongly than ever on large networks such as transportation networks, the Internet and power grids. Engineers are confronted with fundamental questions such as “how to evaluate the robustness of networks for a given service?”, “how to design a robust network?”, because networks always affect the functioning of a service. Robustness is an important issue for many complex networks, on which various dynamic processes or services take place. In this work, we define robustness as follows: a network is more robust if the service on the network performs better, where performance of the service is assessed when the network is either (a) in a conventional state or (b) under perturbations, e.g. failures, virus spreadings etc. In this thesis, we survey a particular line of network robustness research within our general framework: robustness quantification, optimization and the interplay between service and network. Significant progress has been made in understanding the relationship between the structural properties of networks and the performance of the dynamics or services taking place on these networks. We assume that network robustness can be quantified by a topological measure of the network. A brief overview of the topological measures is presented. Each measure may represent the robustness of a network with respect to a certain performance aspect of a service. We focus on the measure known as algebraic connectivity. Evidence collected from literature shows that the algebraic connectivity characterizes network robustness with respect to synchronization of dynamic processes at nodes, random walks on graphs and the connectivity of a network. Moreover, we illustrate that, on a given diameter, graphs with large algebraic connectivity tend to be dense in the core and sparse at the border. Such structures distribute traffic homogeneously and are thus robust in terms of traffic engineering. How do we design a robust network with respect to the metric algebraic connectivity? First, the complete graph has the maximal algebraic connectivity, while its high link density makes it impractical to use due to the cost of constructing links. Constraints on other network features are usually set up to incorporate realistic requirements. For example, constraint on the diameter may guarantee certain end-to-end quality of service levels such as the delay. We propose a class of clique chain structures which optimize the algebraic connectivity and many other robust features among all graphs with diameter D and size N. The optimal graph within the class can be determined either analytically or numerically. Second, complete replacement of an existing infrastructure is expensive. Thus, we design strategies for robustness optimization using minor topological modifications. These strategies are evaluated in various classes of graphs. The robustness quantification, or equivalently, the association of the performance of a service with a topological measure, may be implicit. In this case, we explore the interplay between topology and service in determining the overall performance. Many services on communications and transportation networks are based on shortest path routing. The weight of a link, such as delay or bandwidth, is generally a metric optimized via shortest path routing. Thus, link weight tuning, a mechanism to control traffic, is also considered as part of the service. The interplay between service (shortest path routing and link weight tuning) and topology is investigated for the following performance aspects: (a) the structure of the transport overlay network, which is the union of shortest paths between all node pairs and (b) the traffic distribution in the overlay network. Important new findings are (i) the universal phase transition in overlay structures as we tune the link weight structure over different classes of networks and (ii) the power law traffic distribution in the overlay networks when link weights vary strongly in various classes of networks. Furthermore, we consider the service that measures a network topology as the union of shortest paths among a set of testboxes (nodes). The measured topology is a subgraph of the overlay network, which is again a subgraph of the actual network. The performance in terms of the sampling bias of measuring a network topology is investigated. Our work contributes substantially to a better understanding of the effect of the service (testbox selection) and the actual network structure on the performance with respect to sampling bias. Our investigations on the interplay between service and network reveal again the association between the performance of a service and certain topological feature, and thus, contribute to the quantification of network robustness. The multidisciplinary nature of this research lies not only in the presence of robustness issues in many complex networks, but also in that advances in other disciplines such as graph theory, combinatorics, linear algebra and statistical physics are widely applied throughout the thesis to study optimization problems and the performance of large networks.","robustness; network topology; service; optimization","en","doctoral thesis","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Telecommunications","","","",""
"uuid:a9034441-0e30-4142-8acd-0c55757e12ac","http://resolver.tudelft.nl/uuid:a9034441-0e30-4142-8acd-0c55757e12ac","Characteristics of the Friction Between Aluminium and Steel at Elevated Temperatures During Ball-on-Disc Tests","Wang, L.; Cai, J.; Zhou, J.; Duszczyk, J.","","2009","Appropriate specification of the frictional boundary condition for the finite-element (FE) simulation of metal-forming processes is of great importance to the trustworthiness of the results. The research reported in this communication aimed at understanding the interfacial contact between aluminium and steel at elevated temperatures and determining friction coefficients at this material mating. A series of high-temperature ball-on-disc tests were carried out with the AA7475 aluminium alloy as the material of disc and the hardened H11 steel as the material of ball. A mathematical model developed in the preceding research was employed to account for the evolution of the contact interface during ball-on-disc tests. Friction coefficients at different temperatures and over a number of laps were determined. The shear friction stresses and mean contact pressures along with the progress of the tests at 350–500 °C were calculated. It was found that the friction coefficients obtained from ball-on-disc tests alone were insufficient to represent the frictional interaction between deforming aluminium and steel at elevated temperatures. The evolution of the contact interface with increasing sliding distance must be taken into consideration and the friction behaviour can be reasonably characterized by using friction stress.","Ball-on-disc test; FE Simulation; Extrusion; Friction coefficient","en","journal article","Springer","","","","","","","","Mechanical, Maritime and Materials Engineering","Materials Science and Engineering","","","",""
"uuid:969b6c41-fd13-4b93-a5ec-dd4a1adefceb","http://resolver.tudelft.nl/uuid:969b6c41-fd13-4b93-a5ec-dd4a1adefceb","Dielectric behavior and phase transition in perovskite oxide Pb(Fe1/2Nb1/2)1?xTixO3 single crystal","Jia, Y.; Luo, H.; Or, S.W.; Wang, Y.; Chan, H.L.W.","","2009","Perovskite oxide Pb(Fe1/2Nb1/2)0.52Ti0.48O3 crystals, which were grown using a modified Bridgman method, show a high low-frequency dielectric constant response at room temperature. The Curie phase transition occurs at 523 K. The characteristic frequency of the dielectric dispersion versus the inverse of temperature obeys an Arrhenius relation, which shows a thermally activated behavior. The thermal activation energy for relaxation was found to be ? 0.14?eV. The high dielectric permittivity was attributed to oxygen vacancies and conduction via hopping carriers.","crystal growth from melt; ferroelectric Curie temperature; ferroelectric materials; ferroelectric transitions; hopping conduction; iron compounds; lead compounds; niobium compounds; permittivity; vacancies (crystal)","en","journal article","American Institute of Physics","","","","","","","","Aerospace Engineering","","","","",""
"uuid:5b476c87-e65c-4576-90f8-f9d8594476d9","http://resolver.tudelft.nl/uuid:5b476c87-e65c-4576-90f8-f9d8594476d9","Generation and transport of photoexcited electrons in single-crystal diamond","Heremans, F.J.; Fuchs, G.D.; Wang, C.F.; Hanson, R.; Awschalom, D.D.","","2009","We report time-dependent photocurrent and transport measurements of sub-bandgap photoexcited carriers in nitrogen-rich (type Ib), single-crystal diamond. Transient carrier dynamics are characteristic of trapping conduction with long charge storage lifetimes of ? 3?hours. By measuring the photoexcited Hall effect, we confirm that the charge carriers are electrons and by varying the excitation energy we observe a strong turn-on in the photoconduction at ? 1.9?eV. These findings shed light on sub-bandgap states in nitrogen-doped single-crystal diamond.","diamond; elemental semiconductors; energy gap; Hall effect; nitrogen; photoconductivity","en","journal article","American Institute of Physics","","","","","","","","Applied Sciences","Kavli Institute of Nanoscience","","","",""
"uuid:19f31d86-df63-41db-97a1-4796e8fe436a","http://resolver.tudelft.nl/uuid:19f31d86-df63-41db-97a1-4796e8fe436a","Separation of Ground and Low Vegetation Signatures in LiDAR Measurements of Salt-Marsh Environments","Wang, C.; Menenti, M.; Stoll, M.P.; Feola, A.; Belluco, E.; Marani, M.","","2009","Light detection and ranging (LiDAR) has been shown to have a great potential in the accurate characterization of forest systems; however, its application to salt-marsh environments is challenging because the characteristic short vegetation does not give rise to detectable differences between first and last LiDAR returns. Furthermore, the lack of precisely identifiable references (e.g., buildings, roads, etc.) in marsh areas makes the registration and bias correction of the LiDAR data much more difficult than in conventional urban- or forested-area applications. In this paper, we introduce reliable methods to remove random and systematic errors and to register raw data, as well as a new procedure, to determine the optimal filter window size to separate ground and canopy returns. A limited amount of field observations is used to determine the size of the filtering window which produces the minimally biased estimates of the digital terrain model (DTM). The digital surface model (DSM, representing the canopy top) is then obtained in a similar manner, and the digital vegetationmodel (DVM, representing the vegetation height) is computed as the difference between the DSM and the DTM. We apply this procedure to a study marsh within the Venice Lagoon, Italy, and obtain a high-accuracy DTM. The error (z_LiDAR ? z_field) is 2.2 cm, with a standard deviation of 6.4 cm. The comparison of the estimated DVM with field observations shows an underestimation of the height of the canopy top (17.7 cm, on average). The height of the lowest canopy elements (e.g., basal leaves), however, is significantly correlated to the LiDAR-derived DVM, showing that this contains useful information on the canopy structure.","digital terrain model (DTM); digital vegetation model (DVM); light detection and ranging (LiDAR); salt-marsh environments","en","journal article","IEEE","","","","","","","","Aerospace Engineering","Remote Sensing","","","",""
"uuid:59a1dfa1-bc44-4693-aff1-d94a60875709","http://resolver.tudelft.nl/uuid:59a1dfa1-bc44-4693-aff1-d94a60875709","Evaluation of Plastic Deformation During Metal Forming by Using Lode Parameter","Li, F.; Wang, L.L.; Yuan, S.J.; Wang, X.S.","","2009","In the present research, the relationship between the strain increment and Lode parameter was obtained by using Lode parameter and Levy-Mises equation. The quantitative relation between different strain increments was presented and the relationship between plastic deformation types and Lode parameter was demonstrated. The relations between plastic deformation types and stress states were revealed and they were applied into typical metal forming process. The strain types in the workpiece were analyzed based on the numerical visualization of the values of Lode parameter. This research reveals the important role of the Lode parameter in the analysis of metal flow behavior during metal forming process.","deformation type; Lode parameter; plastic deformation; strain increment","en","journal article","Springer","","","","","","","","Mechanical, Maritime and Materials Engineering","Materials Science and Engineering","","","",""
"uuid:93bfced7-04c7-428a-97f9-4ea0bfc09d24","http://resolver.tudelft.nl/uuid:93bfced7-04c7-428a-97f9-4ea0bfc09d24","The Observable Part of a Network","Van Mieghem, P.; Wang, H.","","2009","","overlay; observability; union of shortest paths","en","journal article","IEEE/ACM","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Network Architectures and Services","","","",""
"uuid:cdaa1a76-b6b0-44f6-a660-a7f2d5df2e0e","http://resolver.tudelft.nl/uuid:cdaa1a76-b6b0-44f6-a660-a7f2d5df2e0e","Digital Receiver Design for Transmitted Reference Ultra-Wideband Systems","Wang, Y.; Leus, G.; Van der Veen, A.J.","","2009","A complete detection, channel estimation, synchronization, and equalization scheme for a transmitted reference (TR) ultra-wideband (UWB) system is proposed in this paper. The scheme is based on a data model which admits a moderate data rate and takes both the interframe interference (IFI) and the intersymbol interference (ISI) into consideration. Moreover, the bias caused by the interpulse interference (IPI) in one frame is also taken into account. Based on the analysis of the stochastic properties of the received signals, several detectors are studied and evaluated. Furthermore, a data-aided two-stage synchronization strategy is proposed, which obtains sample-level timing in the range of one symbol at the first stage and then pursues symbol-level synchronization by looking for the header at the second stage. Three channel estimators are derived to achieve joint channel and timing estimates for the first stage, namely, the linear minimum mean square error (LMMSE) estimator, the least squares (LS) estimator, and the matched filter (MF). We check the performance of different combinations of channel estimation and equalization schemes and try to find the best combination, that is, the one providing a good tradeoff between complexity and performance.","","en","journal article","Hindawi Publishing Corporation","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Telecommunications","","","",""
"uuid:845e1e44-4b52-4a98-8ba1-8e577198fb11","http://resolver.tudelft.nl/uuid:845e1e44-4b52-4a98-8ba1-8e577198fb11","Conceptual design of a biomass terminal (summary)","Wang, W.","","2009","","","","master thesis","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:9200ded4-f3f3-4f74-84c2-1202c33faa77","http://resolver.tudelft.nl/uuid:9200ded4-f3f3-4f74-84c2-1202c33faa77","Unsteady dynamics of cloud cavitating flows around a hydrofoil","Wang, Guoyu; Zhang, Bo; Huang, Biao; Zhang, Mindi","","2009","","resistance & propulsion","","conference paper","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:2b1a5ea4-28cd-474a-9cb8-46eda68957ca","http://resolver.tudelft.nl/uuid:2b1a5ea4-28cd-474a-9cb8-46eda68957ca","Analysis of SWATH ship structures","Cheung, Kwok Fai; Seidl, L.H.; Wang, S.","","2009","","construction","","journal article","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:64bfb415-33ad-4871-ac4f-2b8e0b4803ad","http://resolver.tudelft.nl/uuid:64bfb415-33ad-4871-ac4f-2b8e0b4803ad","Conceptual design of a biomass terminal","Wang, W.","","2009","","","","master thesis","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:bb22e6e3-3be9-446d-a947-719ec680f7cc","http://resolver.tudelft.nl/uuid:bb22e6e3-3be9-446d-a947-719ec680f7cc","Ireland in a warmer world; scientific predictions of the Irish climate in the twenty-first century","McGrath, R.; Lynch, P.; Steele-Dunne, S.C.; Hanafin, J.A.; Nishimura, E.; Nolan, P.; Venkata Ratman, J.; Semmler, T.; Sweeney, C.; Wang, S.","","2008","","climate; Ireland","en","book","Met Eireann","","","","","","","","Civil Engineering and Geosciences","Water Management","","","",""
"uuid:ff66e490-db59-4e3c-b6e2-926da4f074df","http://resolver.tudelft.nl/uuid:ff66e490-db59-4e3c-b6e2-926da4f074df","Algebraic Connectivity Optimization via Link Addition","Wang, H.; Van Mieghem, P.","","2008","","algebraic connectivity; synchronization; optimization; link addition","en","conference paper","ICST","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:990c4c2c-6bf5-4283-8634-dd106e00ec63","http://resolver.tudelft.nl/uuid:990c4c2c-6bf5-4283-8634-dd106e00ec63","Integrated Microstrip Lines With Co–Ta–Zr Magnetic Films","Amiri, P.K.; Rejaei, B.; Zhuang, Y.; Vroubel, M.; Lee, D.W.; Wang, S.X.; Burghartz, J.N.","","2008","","magnetic anisotropy; magnetic microwave devices; microstrip; planar transmission lines; soft magnetic film","en","journal article","IEEE","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Delft Institute of Microsystems and Nanoelectronics","","","",""
"uuid:2f31c7c5-5019-4cab-a9c5-65528f886a76","http://resolver.tudelft.nl/uuid:2f31c7c5-5019-4cab-a9c5-65528f886a76","Noise in sub-micron CMOS image sensors","Wang, X.","Theuwissen, A.J.P. (promotor)","2008","CMOS image sensors are devices that convert illumination signals (light intensity) into electronic signals. The goal of this thesis has been to analyze dominate noise sources in CMOS imagers and to improve the image quality by reducing the noise generated in the CMOS image sensor pixels.","cmos image sensors; temproal noise; buried-channel source follower; rts noise","en","doctoral thesis","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:9a668b83-39c4-4dcd-a438-c936b090c526","http://resolver.tudelft.nl/uuid:9a668b83-39c4-4dcd-a438-c936b090c526","Hydrodynamics and morphodynamics of a seasonally forced tidal inlet system","Lam, N.T.; Stive, M.J.F.; Wang, Z.B.; Verhagen, H.J.; Thuy, V.T.T.","","2008","Hydrodynamics and morphodynamics of a seasonally forced tidal inlet system are investigated using numerical models. The ocean forcing including tidal and wave actions and sediment transport is simulated using Delft3D model. Fluvial processes in Delft3D are taken into account as results from SOBEK RURAL model. Analysis of the numerical simulation results allows enhancing insight the mechanisms behind the behaviours of the tidal inlet system in a tropical monsoon area, under the influences of river flow and seasonal wave actions.","tidal inlet; sobek; Vietnam; hydrodynamics; morphodynamics; monsoon","en","journal article","Hanoi Water Resources University","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:c2563a5b-4b9f-44e7-be7a-6363216d65cc","http://resolver.tudelft.nl/uuid:c2563a5b-4b9f-44e7-be7a-6363216d65cc","Magnetization dynamics in hybrid nanostructures","Wang, X.","Bauer, G.E.W. (promotor)","2008","","","en","doctoral thesis","","","","","","","","","Applied Sciences","","","","",""
"uuid:0d753faf-292d-4ba9-8aad-e9601fdfe9c1","http://resolver.tudelft.nl/uuid:0d753faf-292d-4ba9-8aad-e9601fdfe9c1","Synthesis of zeolite composites with hierarchical porosity","Wang, J.","Coppens, M.O. (promotor); Schmidt-Ott, A. (promotor)","2008","","zeolite; mesoporous; hierarchical; templating; catalysis; mechanism","en","doctoral thesis","","","","","","","","","Applied Sciences","","","","",""
"uuid:41bf5523-87f3-4b32-8adf-15ac8352f277","http://resolver.tudelft.nl/uuid:41bf5523-87f3-4b32-8adf-15ac8352f277","Long-term morphodynamic evolution and energy dissipation in a coastal plain, tidal embayment","Van der Wegen, M.; Wang, Z.B.; Savenije, H.H.G.; Roelvink, J.A.","","2008","The morphodynamic system in alluvial, coastal plain estuaries is complex and characterized by various timescales and spatial scales. The current research aims to investigate the interaction between these different scales as well as the estuarine morphodynamic evolution. Use is made of a process-based, numerical model describing 2-D shallow water equations and a straightforward formulation of the sediment transport and the bed level update. This was done for an embayment with a length of 80 km on a timescale of 3200 years, with and without bank erosion effects. Special emphasis is put on analyzing the results in terms of energy dissipation. Model results show that the basins under consideration evolve toward a state of less morphodynamic activity, which is reflected by (among others) relatively stable morphologic patterns and decreasing deepening and widening of the basins. Closer analysis of the tidal wave shows standing wave behavior with resonant characteristics. Under these conditions, results suggest that the basins aim for a balance between the effect of storage and the effect of fluctuating water level on wave celerity with a negligible effect of friction. Evaluating the model results in terms of energy dissipation reflects the major processes and their timescales (pattern formation, widening, and deepening). On the longer term the basin-wide energy dissipation decreases at a decreasingly lower rate and becomes more uniformly distributed along the basin. Analysis by an entropy-based approach suggests that the forced geometry of the configurations prevents the basins from evolving toward a most probable state.","long-term morphodynamic evolution; tidal embayment; pattern formation; bank erosion; energy dissipation","en","journal article","American Geophysical Union","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:0c03b8a5-c7c5-4fd1-a19d-30a73617976f","http://resolver.tudelft.nl/uuid:0c03b8a5-c7c5-4fd1-a19d-30a73617976f","Probabilistic relevance ranking for collaborative filtering","Wang, J.; Robertson, S.; De Vries, A.P.; Reinders, M.J.T.","","2008","Collaborative filtering is concerned with making recommendations about items to users. Most formulations of the problem are specifically designed for predicting user ratings, assuming past data of explicit user ratings is available. However, in practice we may only have implicit evidence of user preference; and furthermore, a better view of the task is of generating a top-N list of items that the user is most likely to like. In this regard, we argue that collaborative filtering can be directly cast as a relevance ranking problem. We begin with the classic Probability Ranking Principle of information retrieval, proposing a probabilistic item ranking framework. In the framework, we derive two different ranking models, showing that despite their common origin, different factorizations reflect two distinctive ways to approach item ranking. For the model estimations, we limit our discussions to implicit user preference data, and adopt an approximation method introduced in the classic text retrieval model (i.e. the Okapi BM25 formula) to effectively decouple frequency counts and presence/absence counts in the preference data. Furthermore, we extend the basic formula by proposing the Bayesian inference to estimate the probability of relevance (and non-relevance), which largely alleviates the data sparsity problem. Apart from a theoretical contribution, our experiments on real data sets demonstrate that the proposed methods perform significantly better than other strong baselines.","collaborative filtering; recommender systems; probability ranking principle; relevance ranking; personalization","en","journal article","Springer","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Mediamatics","","","",""
"uuid:e238c69d-1109-47c3-9a5e-e93b141f7999","http://resolver.tudelft.nl/uuid:e238c69d-1109-47c3-9a5e-e93b141f7999","A Class of Large-Update and Small-Update Primal-Dual Interior-Point Algorithms for Linear Optimization","Bai, Y.Q.; Lesaja, G.; Roos, C.; Wang, G.Q.; El Ghami, M.","","2008","In this paper we present a class of polynomial primal-dual interior-point algorithms for linear optimization based on a new class of kernel functions. This class is fairly general and includes the classical logarithmic function, the prototype self-regular function, and non-self-regular kernel functions as special cases. The analysis of the algorithms in the paper follows the same line of arguments as in Bai et al. (SIAM J. Optim. 15:101–128, [2004]), where a variety of non-self-regular kernel functions were considered including the ones with linear and quadratic growth terms. However, the important case when the growth term is between linear and quadratic was not considered. The goal of this paper is to introduce such class of kernel functions and to show that the interior-point methods based on these functions have favorable complexity results. They match the currently best known iteration bounds for the prototype self-regular function with quadratic growth term, the simple non-self-regular function with linear growth term, and the classical logarithmic kernel function. In order to achieve these complexity results, several new arguments had to be used.","Linear optimization; Interior-point methods; Primal-dual methods; Complexity; Kernel functions","en","journal article","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:9426fb39-a92e-41e0-9a82-5075d08a7b35","http://resolver.tudelft.nl/uuid:9426fb39-a92e-41e0-9a82-5075d08a7b35","The Effect of Peer Selection with Hopcount or Delay Constraint on Peer-to-Peer Networking","Tang, S.; Wang, H.; Van Mieghem, P.","","2008","","","en","conference paper","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:cacc1e07-acd7-43a6-8d39-b16ad3a3abf0","http://resolver.tudelft.nl/uuid:cacc1e07-acd7-43a6-8d39-b16ad3a3abf0","Adaptive curvelet-domain primary-multiple separation","Herrmann, F.J.; Wang, D.; Verschuur, D.J.","","2008","In many exploration areas, successful separation of primaries and multiples greatly determines the quality of seismic imaging. Despite major advances made by surface-related multiple elimination (SRME), amplitude errors in the predicted multiples remain a problem. When these errors vary for each type of multiple in different ways (as a function of offset, time, and dip), they pose a serious challenge for conventional least-squares matching and for the recently introduced separation by curvelet-domain thresholding. We propose a data-adaptive method that corrects amplitude errors, which vary smoothly as a function of location, scale (frequency band), and angle. With this method, the amplitudes can be corrected by an elementwise curvelet-domain scaling of the predicted multiples. We show that this scaling leads to successful estimation of primaries, despite amplitude, sign, timing, and phase errors in the predicted multiples. Our results on synthetic and real data show distinct improvements over conventional least-squares matching in terms of better suppression of multiple energy and high-frequency clutter and better recovery of estimated primaries.","geophysical techniques; least squares approximations; seismology","en","journal article","Society of Exploration Geophysicists","","","","","","","","Civil Engineering and Geosciences","Imaging Science and Technology","","","",""
"uuid:27afcf33-9164-4e9f-a5c4-16cad2d81526","http://resolver.tudelft.nl/uuid:27afcf33-9164-4e9f-a5c4-16cad2d81526","Relevance models for collaborative filtering","Wang, J.","Reinders, M.J.T. (promotor); De Vries, A.P. (promotor)","2008","","","en","doctoral thesis","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:e764aa50-bbf9-4aca-ada7-7839c0382cd0","http://resolver.tudelft.nl/uuid:e764aa50-bbf9-4aca-ada7-7839c0382cd0","Betweenness centrality in a weighted network","Wang, H.; Martin Hernandez, J.; Van Mieghem, P.","","2008","","graph theory; telecommunication network routing","en","journal article","American Physical Society","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Telecommunications","","","",""
"uuid:65ec884a-7132-4005-a07b-2300145da6b9","http://resolver.tudelft.nl/uuid:65ec884a-7132-4005-a07b-2300145da6b9","A studio based approach for business engineering and mobile services","Wang, Y.","Sol, H.G. (promotor)","2008","In today's world, organizations are becoming increasingly interested in using mobile technology as a means to adapt to the ever-changing environment. An important challenge that the organizations are facing is how to efficiently and effectively support business process carried out by their mobile workers in distributed environments. In the research presented in this dissertation, we examined mobility issues within the context of current organizations' engineering effort. We carried out inductive case studies that revealed the need for an approach that support the reality of mobile workers, and based on these findings we developed a simulation based support studio consisting of an approach and software suite. The support studio can be used to assist organizations to design mobile workforce solutions for the purpose of process performance improvement. We implemented the simulation suite in a prototype and demonstrated its usefulness through two testing case studies. Further, we carried out expert evaluation based on the three dimensions of usefulness, usability, and usage of the studio. We concluded that simulation can be considered to be an effective method of inquiry for improving the effectiveness of business engineering and mobile services in organizations. The studio based approach was considered to be effective in providing insight into the business processes that are enabled by mobile services, through the possibility of carrying out 'what-if' analysis with different scenarios without having to perform the actual implementation of the solution.","business engineering; mobile services; decision support; simulation and modeling","en","doctoral thesis","","","","","","","","","Technology, Policy and Management","","","","",""
"uuid:15494d54-9d42-4433-91ff-b2901438b1a2","http://resolver.tudelft.nl/uuid:15494d54-9d42-4433-91ff-b2901438b1a2","Peer Selection with Hopcount and Delay Constraint","Tang, S.; Wang, H.; Van Mieghem, P.","","2008","We revisit the peer selection problem of finding the most nearby peer from an initiating peer. The metrics to assess the closeness between peers are hopcount and delay, respectively. Based on a dense graph model with i.i.d regular link weight, we calculate the probability density function to reach a peer with minimum hopcount and asymptotically analyze the probability to reach a peer with the smallest delay within a group of peers. Both results suggest that a small peer group size is enough to offer an acceptable content distribution service. We also demonstrate the applicability of our model via Internet measurements.","","en","report","Delft University of Technology","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Network Architectures and Services Group","","","",""
"uuid:793b380c-9c69-46bd-87a2-31ecbb2cd9fa","http://resolver.tudelft.nl/uuid:793b380c-9c69-46bd-87a2-31ecbb2cd9fa","A study on the stochastic finite element method for dynamic problem of nonlinear continuum","Wang, Qing","","2008","","hydrodynamics","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:94662043-2b79-484e-aaab-49da31a48e56","http://resolver.tudelft.nl/uuid:94662043-2b79-484e-aaab-49da31a48e56","Seasonal behaviour of tidal inlets in a tropical monsoon area","Lam, N.T.; Stive, M.J.F.; Verhagen, H.J.; Wang, Z.B.","","2008","Morphodynamics of a tidal inlet system on a micro-tidal coast in a tropical monsoon influenced region is modelled and discussed. Influences of river flow and wave climate on the inlet morphology are investigated with the aid of process-based state-of-the-art numerical models. Seasonal and episodic behaviour of the inlet system under the influence of the forcing processes is then described, modelled and explained.","tidal inlet; tidal lagoon; river flow; seasonal effect","en","conference paper","Copedec","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:ccbf6e20-d5b7-4ef9-b9b5-9a45aac16491","http://resolver.tudelft.nl/uuid:ccbf6e20-d5b7-4ef9-b9b5-9a45aac16491","Detecting changes in extreme precipitation and extreme streamflow in the Dongjiang River Basin in southern China","Wang, W.; Chen, X.; Shi, P.; Van Gelder, P.H.A.J.M.","","2008","","","en","journal article","Copernicus (GmbH)","","","","","","","","","","","","",""
"uuid:28cde23a-4104-4652-98e1-29d7dd01e5a5","http://resolver.tudelft.nl/uuid:28cde23a-4104-4652-98e1-29d7dd01e5a5","Ultra-Thin Deformable Silicon Substrates with Lateral Segmentation and Flexible Metal Interconnect","Zoumpouidis, T.; Wang, L.; Bartek, M.; Jansen, K.M.B.; Ernst, L.J.","","2007","Our progress in developing technology modules for deformable single-crystalline-silicon electronics is presented in this contribution. Additional deformability/reliability is accomplished by modifications of the previously reported ultra-thin and flexible CIRCONFLEX technology (1). The flexibility is added in the last steps of the process flow using a combination of lateral segmentation and flexible metal interconnects. The post-processing nature of the added mechanical flexibility is thought to allow sensors and electronics to be built with proven technologies before they are rendered flexible. The additional deformability/reliability is achieved by lateral segmentation of silicon/dielectric layers and connecting these using flexible electrical interconnect. In the current study, segment thickness (silicon/SiO2) of ~1 ?m, segment size between 150 and 450 ?m, spacing of 20-200 ?m and serpentine-shaped aluminum interconnect transferred onto 8- 10 ?m thick polyimide film are characterized by tensile stretching to find out the reliability limits. Compared to our previous reports (2, 3), next to the processing issues also new electrical integrity results obtained from passive electrical test structures implemented on fully segmented polymer-embedded silicon islands are presented.","","en","journal article","The Electrochemical Society","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:6b8936b8-d2c0-4aa1-9b32-1a579c0c53bb","http://resolver.tudelft.nl/uuid:6b8936b8-d2c0-4aa1-9b32-1a579c0c53bb","Active pixel sensors: The sensor of choice for future space applications","Leijtens, J.; Theuwissen, A.; Rao, P.R.; Wang, X.; Xie, N.","","2007","It is generally known that active pixel sensors (APS) have a number of advantages over CCD detectors if it comes to cost for mass production, power consumption and ease of integration. Nevertheless, most space applications still use CCD detectors because they tend to give better performance and have a successful heritage. To this respect a change may be at hand with the advent of deep sub-micron processed APS imagers (< 0.25-micron feature size). Measurements performed on test structures at the University of Delft have shown that the imagers are very radiation tolerant even if made in a standard process without the use of special design rules. Furthermore it was shown that the 1/f noise associated with deep sub-micron imagers is reduced as compared to previous generations APS imagers due to the improved quality of the gate oxides. Considering that end of life performance will have to be guaranteed, limited budget for adding shielding metal will be available for most applications and lower power operations is always seen as a positive characteristic in space applications, deep sub-micron APS imagers seem to have a number of advantages over CCD's that will probably cause them to replace CCD's in those applications where radiation tolerance and low power operation are important","0,18 micron; CMOS; APS; sunsensor; microned; TNO; TU-Delft; radiation tolerant; low noise","en","conference paper","SPIE","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Electronic Instrumentation","","","",""
"uuid:9993714a-1128-4954-9044-a8a9d69baff6","http://resolver.tudelft.nl/uuid:9993714a-1128-4954-9044-a8a9d69baff6","Morphodynamics of Hue tidal inlets, Vietnam","Lam, N.T.; Stive, M.J.F.; Verhagen, H.J.; Wang, Z.B.","","2007","Morphodynamics of a tidal inlet system on a micro-tidal coast in a tropical monsoon influenced region is modelled and discussed. Effects of tides, waves, river flows and system configuration on the inlet morphologies are investigated with the aid of process-based state-of-the-art numerical models. Seasonal and episodic behaviour of the inlet system under the influence of the forcing processes is then described, modelled and explained.","tidal inlet; coastal morphology; river runoff; inlet stability","en","conference paper","APAC","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:13d94dab-51b5-47b0-953e-efff4e38a7d8","http://resolver.tudelft.nl/uuid:13d94dab-51b5-47b0-953e-efff4e38a7d8","Morphodynamics of Hue tidal inlets","Lam, N.T.; Stive, M.J.F.; Verhagen, H.J.; Wang, Z.B.","","2007","Morphodynamics of a tidal inlet system on a micro-tidal coast in a tropical monsoon influenced region is modeled and discussed. Effects of tides, waves, river flows and system configuration on the inlet morphologies are investigated with the aid of process-based state-of-the-art numerical models. Seasonal and episodic behavior of the inlet system under the influence of the forcing processes is then described, modelled and explained.","tidal inlet; morhpodynamics; numerical model; Vietnam","en","conference paper","Water Resources University Hanoi","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:a724d96a-8011-4981-8335-664717e85680","http://resolver.tudelft.nl/uuid:a724d96a-8011-4981-8335-664717e85680","Long-term interaction between the Dutch coast and the tidal basins","Wang, Z.B.; Elias, E.P.L.; Brière, C.","","2007","","kustbeheer; coastal zone management; getij-inlaten; tidal inlets; kustmorfologie; coastal morphology; sedimenttransport; sediment transport; Waddenzee; Westerschelde","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:b81b8fa3-9107-4931-85af-8fa54f0f8525","http://resolver.tudelft.nl/uuid:b81b8fa3-9107-4931-85af-8fa54f0f8525","Personalization on a peer-to-peer television system","Wang, J.; Pouwelse, J.; Fokker, J.; De Vries, A.P.; Reinders, M.J.T.","","2007","We introduce personalization on Tribler, a peer-to-peer (P2P) television system. Personalization allows users to browse programs much more efficiently according to their taste. It also enables to build social networks that can improve the performance of current P2P systems considerably, by increasing content availability, trust and the realization of proper incentives to exchange content. This paper presents a novel scheme, called BuddyCast, that builds such a social network for a user by exchanging user interest profiles using exploitation and exploration principles. Additionally, we show how the interest of a user in TV programs can be predicted from the zapping behavior by the introduced user-item relevance models, thereby avoiding the explicit rating of TV programs. Further, we present how the social network of a user can be used to realize a truly distributed recommendation of TV programs. Finally, we demonstrate a novel user interface for the personalized peer-to-peer television system that encompasses a personalized tag-based navigation to browse the available distributed content. The user interface also visualizes the social network of a user, thereby increasing community feeling which increases trust amongst users and within available content and creates incentives of to exchange content within the community.","Tribler; BuddyCast; Peer-to-peer (P2P) television system; Personalization; Collaborative filtering; Recommender system","en","journal article","Springer","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Telecommunications","","","",""
"uuid:d6376bce-ccde-458e-837b-904028e875a4","http://resolver.tudelft.nl/uuid:d6376bce-ccde-458e-837b-904028e875a4","Container Ports in China (summary)","Wang, W.","","2007","","","","report","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:8fea7a2f-76b1-4187-92a7-4a31ea3d2b01","http://resolver.tudelft.nl/uuid:8fea7a2f-76b1-4187-92a7-4a31ea3d2b01","Polarization-dependent quantum beats of four-wave mixing in the Luttinger model for bulk semiconductors","Wang, W.; Allaart, K.; Lenstra, D.","","2007","","","en","journal article","American Physical Society","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:8101d5db-c1e7-4d44-8297-5b57542e9827","http://resolver.tudelft.nl/uuid:8101d5db-c1e7-4d44-8297-5b57542e9827","Design of a container terminal in Ningbo Port China","Wang, W.","","2007","","Design assignment","","report","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:ee8d18fb-b846-4009-baa2-67a65ffc32d3","http://resolver.tudelft.nl/uuid:ee8d18fb-b846-4009-baa2-67a65ffc32d3","A Qualitative Comparison of Power Law Generators","Martin Hernandez, J.; Kleiberg, T.; Wang, H.; Van Mieghem, P.","","2007","","network topology; internet; power law; graphs; algorithms","en","conference paper","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:a0a2a18a-e5d6-45d5-b7d2-ff7e8958da1d","http://resolver.tudelft.nl/uuid:a0a2a18a-e5d6-45d5-b7d2-ff7e8958da1d","Structural reliability levels in Ice Class rules","Wang, X.","","2007","","offshore","","conference paper","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:50689b82-502c-49b6-b265-311a592f1642","http://resolver.tudelft.nl/uuid:50689b82-502c-49b6-b265-311a592f1642","Constructing the Overlay Network by Tuning Link Weights","Wang, H.; Van Mieghem, P.","","2007","","","en","conference paper","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:97d6fa9f-cd82-4ce4-9a42-561d6b605cbf","http://resolver.tudelft.nl/uuid:97d6fa9f-cd82-4ce4-9a42-561d6b605cbf","Design of a container terminal in Ningbo Port China (summary)","Wang, W.","","2007","","Design assignment","","report","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:5957742a-6b27-4006-8dff-c1ba2bf6e04a","http://resolver.tudelft.nl/uuid:5957742a-6b27-4006-8dff-c1ba2bf6e04a","Detecting long-memory: Monte Carlo simulations and application to daily streamflow processes","Wang, W.; Van Gelder, P.H.J.A.M.; Vrijling, J.K.; Chen, X.","","2007","","","en","journal article","Copernicus (GmbH)","","","","","","","","Civil Engineering and Geosciences","","","","",""
"uuid:75e05cdb-cfbe-4a27-899b-866ba6a34a6e","http://resolver.tudelft.nl/uuid:75e05cdb-cfbe-4a27-899b-866ba6a34a6e","Morphodynamics of tidal inlets in a tropical monsoon area","Lam, N.T.; Stive, M.J.F.; Verhagen, H.J.; Wang, Z.B.","","2007","Morphodynamics of a tidal inlet system on a micro-tidal coast in a tropical monsoon influenced region is modelled and discussed. Influences of river flow and wave climate on the inlet morphology are investigated with the aid of process-based state-of-the-art numerical models. Seasonal and episodic behaviour of the inlet system under the influence of the forcing processes is then described, modelled and explained.","tidal inlet; Hue; coastal morphology; inlet stability","en","conference paper","Black Sea Coastal Association","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:abb66a4a-4d08-4652-9f16-ae697c85f6cf","http://resolver.tudelft.nl/uuid:abb66a4a-4d08-4652-9f16-ae697c85f6cf","Shifting the Link Weights in Networks","Wang, H.; Van Mieghem, P.","","2007","","","en","conference paper","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:bddebe5b-7124-41db-ad4b-3bdba6a846c3","http://resolver.tudelft.nl/uuid:bddebe5b-7124-41db-ad4b-3bdba6a846c3","The influence of river floods on coastal inlet morphology","Lam, N.T.; Stive, M.J.F.; Verhagen, H.J.; Wang, Z.B.","","2007","The influence of river flood on the coastal inlet morphology is investigated with the aid of process based state-of-the-art numerical models. Hydrodynamics of tidal inlets during a severe flood situation and behavior of the inlets are described and explained.","tidal inlet; Vietnam; Hue; river flood","en","conference paper","Arizona State University","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:89eeb49e-d35e-4f5e-81cf-3781e4840008","http://resolver.tudelft.nl/uuid:89eeb49e-d35e-4f5e-81cf-3781e4840008","Container Ports in China","Wang, W.","","2007","","","","report","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:5942a8dc-7fe4-4379-947a-73a0643a800c","http://resolver.tudelft.nl/uuid:5942a8dc-7fe4-4379-947a-73a0643a800c","Thin Film Interface Fracture Properties at Scales Relevant to Microelectronics","Xiao, A.; Wang, L.G.; Van Driel, W.D.; Van Der Sluis, O.; Yang, D.G.; Ernst, L.J.; Zhang, G.Q.","","2007","","","en","conference paper","IEEE","","","","","","","","Mechanical Maritime and Materials Engineering","","","","",""
"uuid:53768609-192a-4fc4-96fb-9b5d038e09b2","http://resolver.tudelft.nl/uuid:53768609-192a-4fc4-96fb-9b5d038e09b2","Morphodynamic modelling for Thuan An inlet, Vietnam","Lam, T.N.; Stive, M.J.; Verhagen, H.J.; Wang, Z.B.","","2006","Thuan An is a tidal inlet located in Vietnam in a tropical monsoon area. The inlet is very dynamic and variable under the influences of not only tides and waves from the sea but also flows and floods from upstream rivers. Therefore, morphodynamic behaviour of the inlet is very complicated and not well understood. Studies on inlet are also facing with problems of data insufficient. As an effort to gain more understanding on the tidal inlet behaviour, this paper presents a study of the inlet morphodynamics using a numerical modelling approach with the applications several modelling packages including DELFT3D and SOBEK-RURAL developed by WL|Delft Hydraulics. SOBEK has been used to simulate properly the floods in the rivers and on the floodplain. DELFT3D has been used to simulated hydrodynamics of the coastal waters and morphodynamics of the inlet. From the results of the numerical modelling experiments, some behavioural patterns of the inlet, like migration of the inlet channel, can be explained.","tidal inlet; hydrodynamics; morphology; numerical modelling","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:b6fe31bf-395a-4164-b01a-6bd5d07bda85","http://resolver.tudelft.nl/uuid:b6fe31bf-395a-4164-b01a-6bd5d07bda85","Voltage Generation by Ferromagnetic Resonance at a Nonmagnet to Ferromagnet Contact","Wang, X.; Bauer, G.E.W.; Van Wees, B.J.; Brataas, A.; Tserkovnyak, Y.","","2006","A ferromagnet can resonantly absorb rf radiation to sustain a steady precession of the magnetization around an internal or applied magnetic field. We show that, under these ferromagnetic resonance conditions, a dc voltage is generated at a normal-metal electric contact to a ferromagnet with spin-flip scattering. The spin dynamics in the nonmagnetic region is accounted for by a frequency-dependent renormalization of the interface conductances. This mechanism allows sensing of time-dependent magnetizations by established dc electronic techniques.","","en","journal article","American Physical Society","","","","","","","","Applied Sciences","Kavli Institute of Nanoscience","","","",""
"uuid:46934040-c24f-47c1-8f46-17f9ea1f7162","http://resolver.tudelft.nl/uuid:46934040-c24f-47c1-8f46-17f9ea1f7162","Frequency-dependent radiation patterns emitted by THz plasmons on finite length cylindrical metal wires","Deibel, J.A.; Berndsen, N.; Wang, K.; Mittleman, D.M.; Van der Valk, N.C.J.; Planken, P.C.M.","","2006","We report on the emission patterns from THz plasmons propagating towards the end of cylindrical metal waveguides. Such waveguides exhibit low loss and dispersion, but little is known about the dynamics of the terahertz radiation at the end of the waveguide, specifically in the near- and intermediate-field. Our experimental results and numerical simulations show that the near- and intermediate-field terahertz spectra, measured at the end of the waveguide, vary with the position relative to the waveguide. This is explained by the frequency-dependent diffraction occurring at the end of the cylindrical waveguide. Our results show that near-field changes in the frequency content of THz pulses for increasing wire-detector distances must be taken into account when studying surface waves on cylindrical waveguides.","waveguides; surface plasmons; infrared; far","en","journal article","Optical Society of America","","","","","","","","Applied Sciences","Imaging Science and Technology","","","",""
"uuid:558e52cb-24e4-4272-be5b-a6ea64b24ecc","http://resolver.tudelft.nl/uuid:558e52cb-24e4-4272-be5b-a6ea64b24ecc","On the Refraction of Shock Waves at Fe-Be Interface","Yu, M.; Wang, R.","","2006","The paper aims to investigate the refraction phenomena of shock waves at ferrum-beryllium (Fe-Be) interface. The equations of state of Fe and Be adopt stiffen gas formula. For the regular refraction, the shock polar theory is employed. The critical angles of transition of the regular to irregular refraction about the different shock intensity are obtained. Besides, the reflected waves of incident shock waves are rarefaction waves. For the irregular refraction, the numerical simulation method with shock-capturing scheme is employed. To the shock waves with different intensity, there always exist the precursory refracted shock waves under different incident angles, and the refraction images are more complicated under larger incident angles.","Fe-Be interface; refraction phenomena of shock waves; shock polar theory; shock-capturing method","en","conference paper","","","","","","","","","","","","","",""
"uuid:4c7f37da-c958-4f4a-a935-43e2651e5c54","http://resolver.tudelft.nl/uuid:4c7f37da-c958-4f4a-a935-43e2651e5c54","Coastal inlets and tidal basins","Stive, M.J.F.; de Vriend, H.J.; Dronkers, J.; van Dongeren, A.; Wang, Z.B.","","2006","","","en","lecture notes","TU Delft, Department Hydraulic Engineering","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:dfe2720c-b194-444b-bfdc-5179d9f72ab8","http://resolver.tudelft.nl/uuid:dfe2720c-b194-444b-bfdc-5179d9f72ab8","Habitattoets: Effecten bagger- en stortactiviteiten t.b.v. havenonderhoud in Zeeuwse wateren","Baptist, H.; Tatman, S.; Kessel, T. van; Moorsel, G.W.N.M. van; Wang, Z.B.; Erftemeijer, P.L.A.","","2006","","onderhoudsbaggerwerken; maintenance dredging; habitats; habitats; natuurbeheer; nature management; kustmorfologie; coastal morphology; slib; mud","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:d467b1a4-22ce-4009-b4cd-2c04dcd56d03","http://resolver.tudelft.nl/uuid:d467b1a4-22ce-4009-b4cd-2c04dcd56d03","Stochasticity, nonlinearity and forecasting of streamflow processes","Wang, W.","Vrijling, J.K. (promotor)","2006","Abstract not available","streamflow; hydrological forecast; time series analysis; long memory; stationarity; autoregressive conditional heteroskedasticity; nonlinearity; chaos; predictability; artificial neural network; data-driven model","en","doctoral thesis","IOS Press","","","","","","","","Civil Engineering and Geosciences","","","","",""
"uuid:1a8eb02d-c593-4033-bb5e-5896ce0c188c","http://resolver.tudelft.nl/uuid:1a8eb02d-c593-4033-bb5e-5896ce0c188c","Effecten van verschillende scenario's van kustonderhoud: Resultaten lange-termijn simulaties morfologische ontwikkeling Nederlandse Noordzeekust","Wang, Z.B.; Steetzel, H.J.; Koningsveld, M. van","","2006","","kustonderhoud; coastal maintenance; veiligheid; safety; ecologie; ecology; kustbeleid; coastal zone planning","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:ee866da5-1826-484e-ba79-a392b5147320","http://resolver.tudelft.nl/uuid:ee866da5-1826-484e-ba79-a392b5147320","Modelling of Cohesive Sediment Transport in the Maasmond Area","Wang, L.","","2006","In the Dutch coastal zone, where the marine environment is highly dynamic owing to tidal currents, wind-driven, wave-driven, and density-driven currents and waves, the cohesive sediment dynamics is always a great concern to transportation authority and coastal managers. So far, a lot research has been contributed on the cohesive sediment dynamics such as transportation, deposition and resuspension. In addition, the origin of the cohesive sediment is also of a great interest to researchers. In this study, I will explore some underlying mechanics governing cohesive sediment dynamics with the help of numerical models based on Delft3D which is a powerful software package developed by WL | Delft Hydraulics. This study starts with the large-scale modelling of the North Sea using ZUNO grid, which has been verified by WL | Delft Hydraulics. During this research the original model is simplified due to the limitation of relevant data. Through the comparison with the measured water level, both of the simplified and original ZUNO models present a good performance. The simplification doesn’t cause significant change on the simulated results compared with the original model. Based on scale-based philosophy of Vriend, the simulated water level and current velocity on corresponding grids are provided to another model based on the RIJMAMO grid as boundary conditions. The RIJMAMO model is a local refinement for the Dutch coastal area.","Modelling of Cohesive Sediment Transport; Maasmond Area; Dutch coastal zone; Delft3D; ZUNO grid; RIJMAMO; Delft Cluster; CT05.20; Noordzee & Kust; CT05.24.11; morfodynamiek van Noordzee","en","report","Delft Cluster","","","","","","","","","","","","",""
"uuid:52f8854c-d4c3-4426-ba3a-65674d43ec0a","http://resolver.tudelft.nl/uuid:52f8854c-d4c3-4426-ba3a-65674d43ec0a","Rivierwaterbouwkunde","de Vriend, H.J.; Havinga, H.; Visser, P.J.; Wang, Z.B.","","2006","","","nl","lecture notes","TU Delft, Department Hydraulic Engineering","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:64c65a8e-a194-4f8d-a1a1-70839f1cfd87","http://resolver.tudelft.nl/uuid:64c65a8e-a194-4f8d-a1a1-70839f1cfd87","Scale estimation in two-band filter attacks on QIM watermarks","Wang, J.; Shterev, I.D.; Lagendijk, R.L.","","2006","This paper presents a scheme for estimating two-band amplitude scale attack within a quantization-based watermarking context. Quantization-based watermarking schemes comprise a class of watermarking schemes that achieves the channel capacity in terms of additive noise attacks1. Unfortunately, Quantization-based watermarking schemes are not robust against Linear Time Invariant (LTI) filtering attacks. We concentrate on a multi-band amplitude scaling attack that modifies the spectrum of the signal using an analysis/synthesis filter bank. First we derive the probability density function (PDF) of the attacked data. Second, using a simplified approximation of the PDF model, we derive a Maximum Likelihood (ML) procedure for estimating two-band amplitude scaling factor. Finally, experiments are performed with synthetic and real audio signals showing the good performance of the proposed estimation technique under realistic conditions.","watermarking; quantization; maximum likelihood estimation; multi-band","en","conference paper","SPIE","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Multimedia Signal Processing","","","",""
"uuid:673300b9-046c-4b16-943d-dc23f74b78e9","http://resolver.tudelft.nl/uuid:673300b9-046c-4b16-943d-dc23f74b78e9","Cutter teeth logistics study","Wang, Z.","","2006","","","","master thesis","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:357b3fb5-8dfc-4d75-973b-4c1b6dc2d49d","http://resolver.tudelft.nl/uuid:357b3fb5-8dfc-4d75-973b-4c1b6dc2d49d","Topological Characteristics of the Dutch Road Infrastructure","Jamakovic, A.; Wang, H.; Van Mieghem, P.","","2006","","","en","conference paper","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:39a867c9-4a16-48eb-b91c-5ba23e3e3de9","http://resolver.tudelft.nl/uuid:39a867c9-4a16-48eb-b91c-5ba23e3e3de9","Experimental study on the performance of the multiple-layer breakwater","Wang, Y.","","2006","","hydrodynamics","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:2ceeef8e-2284-4b05-8285-106fd9c0530b","http://resolver.tudelft.nl/uuid:2ceeef8e-2284-4b05-8285-106fd9c0530b","The response of bucket foundation under horizontal dynamic loading","Wang, Y.","","2006","","hydrodynamics","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:7fc39e59-0de2-475a-8433-0d9e736231d8","http://resolver.tudelft.nl/uuid:7fc39e59-0de2-475a-8433-0d9e736231d8","Dynamics of thin-film spin-flip transistors with perpendicular source-drain magnetizations","Wang, X.; Bauer, G.E.W.; Hoffman, A.","","2006","","","en","journal article","American Physical Society","","","","","","","","Applied Sciences","","","","",""
"uuid:cb07419d-788c-4bde-805f-218763ad09f6","http://resolver.tudelft.nl/uuid:cb07419d-788c-4bde-805f-218763ad09f6","Modeling motors in Runmec","Wang, Z.","","2006","","Computer assignment","","report","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:abed1df3-52fe-40b4-9c9e-e1e1ab62649a","http://resolver.tudelft.nl/uuid:abed1df3-52fe-40b4-9c9e-e1e1ab62649a","Cutter teeth logistics study (summary)","Wang, Z.","","2006","","","","master thesis","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:5c7e5ed3-98ac-4cac-9b88-edbf5b86a575","http://resolver.tudelft.nl/uuid:5c7e5ed3-98ac-4cac-9b88-edbf5b86a575","Shifting the Link Weights in Networks","van Mieghem, P.; Wang, H.","","2006","","","en","report","Delft University of Technology","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:db6f684b-cbb1-4d8a-9783-72951dd8afd5","http://resolver.tudelft.nl/uuid:db6f684b-cbb1-4d8a-9783-72951dd8afd5","A qualitative comparison of power law generators","van Mieghem, P.; Hernandez, J.M.; Kleiberg, T.; Wang, H.","","2006","","","en","report","Delft University of Technology","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:10c081ea-dc15-4bdd-b9cd-89a7ee086929","http://resolver.tudelft.nl/uuid:10c081ea-dc15-4bdd-b9cd-89a7ee086929","High performance repetitive control of PWM DC-AC converters with real-time phase-lead FIR filter","Ye, Y.; Zhou, K.; Wang, D.; Wang, J.C.","","2006","","","en","journal article","Institute of Electrical and Electronics Engineers IEEE","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:1fa97a37-4a32-41be-8f60-7ef750d56041","http://resolver.tudelft.nl/uuid:1fa97a37-4a32-41be-8f60-7ef750d56041","Zero-phase odd-harmonic repetitive controller for a single-phase PWM inverter","Wang, D.","","2006","","","en","journal article","IEEE","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:8a93fc93-ab79-4fcb-a7e0-f4a7c4b5a6ac","http://resolver.tudelft.nl/uuid:8a93fc93-ab79-4fcb-a7e0-f4a7c4b5a6ac","Bouwstenen voor nieuw morfologisch SOBEK-model van de Rijn-Maasmonding","Mosselman, E.; Crebas, J.I.; Icke, J.; Sloff, C.J.; Wang, Z.B.","","2005","","estuariene morfologie; estuarine morphology; geomorfologische modellen; geomorphological models; zandtransport; sand transport; zandtransportformules; sand transport formulae; sedimenttransportformules; sediment transport formulae; slibtransport; mud tran","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:0fa61991-0b71-432f-962a-0bec67e7f3da","http://resolver.tudelft.nl/uuid:0fa61991-0b71-432f-962a-0bec67e7f3da","Design reuse in product shape modeling: A study of freeform feature reuse by signal processing techniques","Wang, C.","Stappers, P.J. (promotor); Vergeest, J.S.M. (promotor)","2005","Lack of facilities in supporting design reuse is a serious problem in product shape modeling, especially in computer-aided design systems. This becomes a bottleneck of fast shape conceptualization and creation in consumer product design, which consequently prohibits creativity and innovation. In the past, several efforts have been made in order to improve this situation, with confined methodologies in the spatial domain, following conventional ways of geometrical operations. These domain dependent researches did not yield satisfactory solutions. Looking at the state of the art technologies, to find a better solution, an investigation applying interdisciplinary knowledge has to be conducted. The present study aimed at finding a systematic approach to support design reuse in shape modeling, especially Freeform Feature (FFF) reuse, by hypothesizing that a better solution could be achieved by applying signal processing techniques. This global goal was further decomposed into a number of concrete objectives, each correlated to a broad spectrum of domain specific knowledge. Investigations on relevant subjects enrich the aggregation of knowledge, especially that concerning computer-assisted technologies in industrial design field. Solutions of this study functionally extend the capability of shape modeling, and enhance the interchange ability of shape depiction between the spatial and the frequency domain. A number of examples were employed to test the methods and mathematical formulations proposed. The results affirm that the hypothesis works, and the methodology developed in this research are both effective and beneficial.","CAD/CAM; shape modeling; Fourier transforms; signal processing; shape descriptor","en","doctoral thesis","","","","","","","","","Design, Engineering and Production","","","","",""
"uuid:baf45e51-c4da-473b-a6b0-6573e42d8aef","http://resolver.tudelft.nl/uuid:baf45e51-c4da-473b-a6b0-6573e42d8aef","Wi-Fi Walkman: A wireless handhold that shares and recommends music on peer-to-peer networks","Wang, J.; Reinders, M.J.T.; Pouwelse, J.; Lagendijk, R.L.","","2005","The Wi-Fi walkman is a mobile multimedia application that we developed to investigate the technological and usability aspects of human-computer interaction with personalized, intelligent and context-aware wearable devices in peer-to-peer wireless environments such as the future home, office, or university campuses. It is a small handheld device with a wireless link that contains music content. Users carry their own walkman around and listen to music. All this music content is distributed in the peer-to-peer network and is shared using ad-hoc networking. The walkman naturally interacts with the users and users’ interest with each other in a peer-to-peer environment. Without annoying interactions, it can learn the users’ music interest/taste and consequently provide personalized music recommendation according to the current situated context and user’s interest.","peer-to-peer networks; recommendation; personalization; user's interest","en","conference paper","SPIE","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Pattern Recognition and Bioinformatics","","","",""
"uuid:789ba95e-5ebc-4c91-b2d6-29b0a4c97821","http://resolver.tudelft.nl/uuid:789ba95e-5ebc-4c91-b2d6-29b0a4c97821","Testing and modelling autoregressive conditional heteroskedasticity of streamflow processes","Wang, W.; Van Gelder, P.H.A.J.M.; Vrijling, J.K.; Ma, J.","","2005","Conventional streamflow models operate under the assumption of constant variance or season-dependent variances (e.g. ARMA (AutoRegressive Moving Average) models for deseasonalized streamflow series and PARMA (Periodic AutoRegressive Moving Average) models for seasonal streamflow series). However, with McLeod-Li test and Engle's Lagrange Multiplier test, clear evidences are found for the existence of autoregressive conditional heteroskedasticity (i.e. the ARCH (AutoRegressive Conditional Heteroskedasticity) effect), a nonlinear phenomenon of the variance behaviour, in the residual series from linear models fitted to daily and monthly streamflow processes of the upper Yellow River, China. It is shown that the major cause of the ARCH effect is the seasonal variation in variance of the residual series. However, while the seasonal variation in variance can fully explain the ARCH effect for monthly streamflow, it is only a partial explanation for daily flow. It is also shown that while the periodic autoregressive moving average model is adequate in modelling monthly flows, no model is adequate in modelling daily streamflow processes because none of the conventional time series models takes the seasonal variation in variance, as well as the ARCH effect in the residuals, into account. Therefore, an ARMA-GARCH (Generalized AutoRegressive Conditional Heteroskedasticity) error model is proposed to capture the ARCH effect present in daily streamflow series, as well as to preserve seasonal variation in variance in the residuals. The ARMA-GARCH error model combines an ARMA model for modelling the mean behaviour and a GARCH model for modelling the variance behaviour of the residuals from the ARMA model. Since the GARCH model is not followed widely in statistical hydrology, the work can be a useful addition in terms of statistical modelling of daily streamflow processes for the hydrological community.","","en","journal article","European Geosciences Union (EGU)","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:cc957424-7611-4dd5-b84c-91ee9b1283d0","http://resolver.tudelft.nl/uuid:cc957424-7611-4dd5-b84c-91ee9b1283d0","CMOS bandgap references and temperature sensors and their applications","Wang, G.","Meijer, G.C.M. (promotor); van Roermund, A.H.M. (promotor)","2005","Two main parts have been presented in this thesis: device characterization and circuit. In integrated bandgap references and temperature sensors, the IC(VBE, characteristics of bipolar transistors are used to generate the basic signals with high accuracy. To investigate the possibilities to fabricate high-precision bandgap references and temperature sensors in low-cost CMOS technology, the electrical characteristics of substrate bipolar pnp transistors have been investigated over a wide temperature range. The measurement results of the IC(VBE, characteristics show that at a moderate current range, a good exponential relation between the base-emitter voltage and the collector current exists. Moreover, the temperature behavior of the base-emitter voltage can be well modeled with the well-known Gummel-Poon model. Even the negative correlation between the extracted parameters Vgo and is similar to that earlier reported for bipolar technology. Non-ideal effects, for instance the low forward common-emitter current gain (BF), high base resistance, low and high level injections and stress effect, etc. have also been analysed. Methods and suggestions have been given to get rid of the non-ideal effects in order to improve the performances of the bandgap references and temperature sensors. In order to design high-performance temperature sensors or bandgap references in CMOS technology, in addition to exploiting the best characteristics of the bipolar transistors, we needed to apply advanced circuit techniques. In this thesis, special advanced circuit techniques for application in low-speed sensor systems have been described. For instance, three signal auto-calibration can be applied to eliminate the additive and multiplexitive uncertainties of the transfer circuit. Chopping technique has been applied to reduce the low-frequency interferences and 1/f noise. By applying dynamic element matching (DEM), errors due to component mismatching can be reduced to second order. In the described sensor systems, indirect A/D converters (modulators) have been applied, because of their simplicity, high accuracy and high resolution. To reduce the effects of low-frequency interference and 1/f noise, a chopping technique was applied. To increase the input range, pre-amplifier and divider are applied for small and large signals respectively. By applying DEM technique the errors due to component mismatching can be significantly reduced. Accurate pre-amplifier and divider can be realized in this way. A circuit design for the thermocouple interface has been presented. On-chip bandgap reference and temperature sensor have been included for auto-calibration and the compensation of the reference junction temperature. Research on the characteristics of bipolar transistors fabricated in CMOS technology has been applied for designing high performance bandgap reference and temperature sensor. A switch-capacitor input circuit has been applied which allows the thermocouple voltage to have a rail-to-rail common-mode voltage. Furthermore, advanced circuit techniques such as three-signal auto-calibration, DEM and chopping mentioned above have been applied too. The interface circuit has been designed and implemented in 0.7-ïm CMOS technology. The interface has been tested and the test results have been presented in this thesis. The design and test results of a DEM SC instrumentation amplifier have also been presented in this thesis","CMOS technology; substrate bipolar transistors; temperature sensor; bandgap reference; voltage-to-period converter; three signal auto-calibration; dynamic element matching","en","doctoral thesis","Optima Grafische Communicatie","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:4fb8d283-7df6-4598-a3b9-379e40fd13f4","http://resolver.tudelft.nl/uuid:4fb8d283-7df6-4598-a3b9-379e40fd13f4","Modeling of channel patterns in short tidal basins","Marciano, R.; Wang, Z.B.; Hibma, A.; De Vriend, H.J.; Defina, A.","","2005","We model branching channel patterns in short tidal basins with two methods. A theoretical stability analysis leads to a relationship between the number of channels and physical parameters of the tidal system. The analysis reveals that width and spacing of the channels should decrease as the slope of the bottom profile and the Shields parameter increase and as the mean water depth decreases. In general, the channel depth should halve at every bifurcation. These theoretical results agree well with the field data from the Dutch Wadden Sea. A numerical model based on Delft3D, a software system of WL/Delft Hydraulics, is used to simulate the time evolution of a channel network in a geometrically simplified basin of similar dimensions as the Wadden Sea basins. The resulting channel network displays a three-times branching behavior, similar to the three- to four-times branching patterns observed in the Wadden Sea. The simulated channel pattern satisfies the relation derived from the theoretical analysis. The results of this pattern analysis provide for additional validation of two-dimensional/three-dimensional process-based morphodynamic models of tidal basins.","estuaries; morphology; numerical model","en","journal article","American Geophysical Union","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:8ddb88b1-3976-4d98-8ba1-077815afa615","http://resolver.tudelft.nl/uuid:8ddb88b1-3976-4d98-8ba1-077815afa615","Finite element analysis of two-dimensional nonlinear sloshing problems in random excitations","Wang, C.Z.","","2005","","hydrodynamics","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:2b1acb2a-d4db-40ab-8cb3-d57033a47e57","http://resolver.tudelft.nl/uuid:2b1acb2a-d4db-40ab-8cb3-d57033a47e57","The Stability of Paths in a Dynamic Network","Kuipers, F.A.; Wang, H.; Van Mieghem, P.","","2005","","network dynamics; link-state update policy; shortest path; link weight perturbation; quality of service","en","conference paper","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:c1407273-bb5f-455c-a220-7f2bb7fca870","http://resolver.tudelft.nl/uuid:c1407273-bb5f-455c-a220-7f2bb7fca870","Coastal inlets and Tidal basins","de Vriend, H.J.; Dronkers, J.; Stive, M.J.F.; van Dongeren, A.; Wang, Z.B.","","2005","","","en","lecture notes","TU Delft, Department Hydraulic Engineering","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:8a2aaa9c-5e88-4508-a2c0-4bc429e32bf1","http://resolver.tudelft.nl/uuid:8a2aaa9c-5e88-4508-a2c0-4bc429e32bf1","A long-term morphological model for the whole Dutch Coast: Part 1: model formulation - part 2: application of the model","Steetzel, H.J.; Wang, Z.B.","","2004","","numerieke modellen; numerical modelling; sedimenttransportformules; sediment transport formulae; getij-inlaten; tidal inlets; kustbeheer; coastal zone management; modelonderzoek; modelling","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:14f7b6e8-dc65-4d47-a040-c63603e27a82","http://resolver.tudelft.nl/uuid:14f7b6e8-dc65-4d47-a040-c63603e27a82","Antenna effects in terahertz apertureless near-field optical microscopy","Wang, K.; Mittleman, D.M.; Van der Valk, N.C.J.; Planken, P.C.M.","","2004","We have performed measurements on terahertz (THz) apertureless near-field microscopy that show that the temporal shape of the observed near-field signals is approximately proportional to the time-integral of the incident field. Associated with this signal change is a bandwidth reduction by approximately a factor of 3 which is observed using both a near-field detection technique and a far-field detection technique. Using a dipole antenna model, it is shown how the observed effects can be explained by the signal filtering properties of the metal tips used in the experiments.","dipole antennas; near-field scanning optical microscopy","en","journal article","American Institute of Physics","","","","","","","","Applied Sciences","Imaging Science and Technology","","","",""
"uuid:9a335ba4-d69f-4cf6-8c24-998085c64fe5","http://resolver.tudelft.nl/uuid:9a335ba4-d69f-4cf6-8c24-998085c64fe5","Parallel recording with optical waveguide array","Wang, H.; Groen, F.H.; Pereira, S.F.; Braat, J.J.M.","","2004","We present an analysis of the reading capability of a novel optical pickup consisting of a single-mode and a multi-mode rectangular waveguide. According to the simulations, if one has prior information about the structure of the disk, superresolution readout could be achieved. The proposed system has the advantage to be compact and should be straightforward to be extended to arrays. The working distance of this optical pickup can be adapted from near- to farfield by changing the length of the multi-mode waveguide.","waveguide array; parallel optical pickup; optical recording; data transfer rate; super-resolution reading","en","conference paper","SPIE","","","","","","","","Applied Sciences","Optics Research Groep","","","",""
"uuid:80d74f44-df9a-444b-a22f-d48e6d4c85d4","http://resolver.tudelft.nl/uuid:80d74f44-df9a-444b-a22f-d48e6d4c85d4","Design of a plant producing 500,000 tones/annum synthetic oil products from natural gas, using Fischer-Tropsch technology","Bai, B.; Hu, J.; Liu, N.; Jiao, Y.; Wang, Z.","","2004","Document(en) uit de collectie Chemische Procestechnologie","Fischer-Tropsch synthesis; hydrocracking; syngas production; combined autothermal reforming; natural gas","en","report","Delft University of Technology","","","","","","","2014-01-23","Applied Sciences","DelftChemTech","","","",""
"uuid:cd7461e0-80ac-41f9-b82c-abc738dc9c45","http://resolver.tudelft.nl/uuid:cd7461e0-80ac-41f9-b82c-abc738dc9c45","Exergy loss reduction by combining exothermic and endothermic reaction routes","Wang, B.; Lumluksanaphaiboon, M.; Muraza, O.; Lin, W.K.; Zou, Y.","","2004","Document(en) uit de collectie Chemische Procestechnologie","exergy; shell and tube reactor; exothermic; endothermic; oxidative dehydrogenation; catalytic dehydrogenation; propane; ethylene; propylene","en","report","Delft University of Technology","","","","","","","2014-01-13","Applied Sciences","DelftChemTech","","","",""
"uuid:d2b87433-1aac-4221-9899-e6e42896d59e","http://resolver.tudelft.nl/uuid:d2b87433-1aac-4221-9899-e6e42896d59e","Management Information Systems in an Organization","Wang, L.","","2004","","","","master thesis","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:c619e3a5-647b-4d40-8010-2ba3730b3493","http://resolver.tudelft.nl/uuid:c619e3a5-647b-4d40-8010-2ba3730b3493","Chinese Inland Waterway Transportation","Wang, Z.","","2004","","","","report","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:e5616d30-459c-4b71-a1f0-909093986b95","http://resolver.tudelft.nl/uuid:e5616d30-459c-4b71-a1f0-909093986b95","Micromechanical modeling of stress evolution induced during cure in a particle-filled electronic packaging polymer","Jansen, K.M.B.; Wang, L.G.; Ernst, L.J.; Zhang, G.Q.; Bressers, H.J.L.","","2004","","","en","journal article","IEEE","","","","","","","","Mechanical, Maritime and Materials Engineering","","","","",""
"uuid:89eb7dc6-3858-4eeb-ba09-d1855512db27","http://resolver.tudelft.nl/uuid:89eb7dc6-3858-4eeb-ba09-d1855512db27","Calculation of shape anisotropy for micropatterned thin Fe-Ni films for on-chip RF applications","Vroubel, M.; Rejaei, B.; Burghartz, J.N.; Crawford, A.M.; Wang, S.X.","","2004","","","en","journal article","IEEE","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:bfc0c8e5-9402-446e-af9e-fb78b0d89b12","http://resolver.tudelft.nl/uuid:bfc0c8e5-9402-446e-af9e-fb78b0d89b12","Chinese Inland Waterway Transportation (summary)","Wang, Z.","","2004","","","","report","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:db62239e-30a0-40f4-ab1a-ae90bd752606","http://resolver.tudelft.nl/uuid:db62239e-30a0-40f4-ab1a-ae90bd752606","Management Information Systems in an Organization (summary)","Wang, L.","","2004","","","","master thesis","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:1e9429b9-40e6-449a-aec8-04ea95b916ae","http://resolver.tudelft.nl/uuid:1e9429b9-40e6-449a-aec8-04ea95b916ae","Charge Ordering, Commensurability, and Metallicity in the Phase Diagram of the Layered NaxCoO2","Foo, M.L.; Wang, Y.; Watauchi, S.; Zandbergen, H.W.; THe, T.; Cava, R.J.; Ong, N.P.","","2004","","","en","journal article","American Physical Society","","","","","","","","Mechanical, Maritime and Materials Engineering","","","","",""
"uuid:d84cf54e-e4f5-430a-b3da-c40748abf85e","http://resolver.tudelft.nl/uuid:d84cf54e-e4f5-430a-b3da-c40748abf85e","Optical waveguide focusing system with short free-working distance","Wang, H.; Groen, F.H.; Pereira, S.F.; Braat, J.J.M.","","2003","In photonics, light usually diffracts in all directions when it emerges from a planar optical waveguide. Besides this fact, in this letter we show that a waveguide with a rectangular cross section can be turned to a focusing system by using three-dimensional self-imaging technique. We obtained a configuration where the focus of the field lies outside the waveguide, in air, with a spot size of approximately the resolution limit of half a wavelength. This type of waveguide could be used as a coupling element in integrated optics or in high numerical aperture optical systems.","rectangular waveguides; optical waveguide theory; optical focusing; optical planar waveguides","en","journal article","American Institute of Physics","","","","","","","","Applied Sciences","Imaging Science and Technology","","","",""
"uuid:caddfefc-6364-4af3-8977-7fd72ab393c9","http://resolver.tudelft.nl/uuid:caddfefc-6364-4af3-8977-7fd72ab393c9","Development and application of a large-scale morphological model of the Dutch coast - phase 2: Formulation and application of the PONTOS model version 1.4","Steetzel, H.J.; Wang, Z.B.","","2003","","morfodynamische modellen; morphodynamic models; kustmorfologie; coastal morphology; zandtransport; sand transport; zandsuppletie; sand nourishment; Noordzee","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:450fce71-b09b-4198-9615-b021f81f58c0","http://resolver.tudelft.nl/uuid:450fce71-b09b-4198-9615-b021f81f58c0","Tensile stress in hard metal films","Janssen, G.C.A.M.; Dammers, A.J.; Sivel, V.G.M.; Wang, W.R.","","2003","Thin films on substrates are usually in a stressed state. An important, but trivial, contribution to that stress stems from the difference in thermal expansion coefficient of substrate and film. Much more interesting are the intrinsic stresses, resulting from the growth and/or microstructure of the film. Intrinsic compressive stress was explained by d’Heurle in 1970. Intrinsic tensile stress for recrystallizing metal films was treated succesfully by Doljack and Hoffman in 1972. In the present letter we explain the occurrence of tensile stress in nonrecrystallizing metal films. The explanation is based on modern grain growth models and accurate stress measurements. The key ingredient to the explanation is the proof of the existence of a stress gradient in nonrecrystallizing metal films.","metallic thin films; tensile strength; internal stresses; thermal expansion; grain growth","en","journal article","American Institute of Physics","","","","","","","","Mechanical, Maritime and Materials Engineering","Materials Science and Engineering","","","",""
"uuid:b983f389-3ff6-4d19-979e-8f72a4629b75","http://resolver.tudelft.nl/uuid:b983f389-3ff6-4d19-979e-8f72a4629b75","Toepasbaarheid van ESTMORF als instrument voor beheer van buitendelta's: Bureaustudie met Haringvlietmonding als case","Wang, Z.B.","","2003","","morfodynamische modellen; morphodynamic models; buitendelta's; outer deltas; Haringvliet","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:51835ae7-10fe-416f-86fd-1c517665c0b7","http://resolver.tudelft.nl/uuid:51835ae7-10fe-416f-86fd-1c517665c0b7","Invloed van ingrepen in het mondinggebied van de Westerschelde: Evaluatie aan de hand van ESTMORF berekeningen","Wang, Z.B","","2003","","kustmorfologie; coastal morphology; riviermorfologie; river morphology; rivierverbetering; river improvement; vaargeulen; navigation channels; kustverdediging; coast protection; Westerschelde","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:44b017a0-6ab4-4442-8854-e17a5d5d68e0","http://resolver.tudelft.nl/uuid:44b017a0-6ab4-4442-8854-e17a5d5d68e0","Ontwikkeling van een lange-termijn morfologisch model voor de Nederlandse kust","Wang, Z.B.; Steetzel, H.J.","","2003","","kustmorfologie; coastal morphology; zandtransportmodellen; sand transport models; zandtransport; sand transport","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:df7a5524-b785-45ba-a126-ef7d8f98d174","http://resolver.tudelft.nl/uuid:df7a5524-b785-45ba-a126-ef7d8f98d174","Evaluatie van het beleid voor vaargeulonderhoud en zandwinning sinds de tweede vaargeulverdieping op basis van veldwaarnemingen en het verbeterde cellenconcept Westerschelde","Jeuken, M.C.J.L.; Tanczos, I.C.; Wang, Z.B.","","2003","","Westerschelde; vaargeulen; navigation channels; vaargeulverdieping; channel deepening; zandwinning; sand dredging; baggerwerken; dredging works","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:c5160834-bb6a-4a6a-a1b3-90e64f0957f0","http://resolver.tudelft.nl/uuid:c5160834-bb6a-4a6a-a1b3-90e64f0957f0","Novel catalytic method for alcohol oxidation","Luo, L.; Wang, W.; Zhao, S.; Zhu, Z.","","2003","Document(en) uit de collectie Chemische Procestechnologie","3,3-dimethylbutyraldehyde; 3,3-dimethylbutanol; TEMPO; RuCl2(PPh3)3; catalytic oxidation","en","report","Delft University of Technology","","","","","","","2013-02-11","Applied Sciences","DelftChemTech","","","",""
"uuid:637359e9-95a1-40a0-b6f0-6d3f6b834c18","http://resolver.tudelft.nl/uuid:637359e9-95a1-40a0-b6f0-6d3f6b834c18","Local and global finite element analysis of an adhesively bonded aluminium structure","Wang, Xinyu","","2003","","construction","","conference paper","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:a7dd7970-54b5-4040-9f20-c9959949cb84","http://resolver.tudelft.nl/uuid:a7dd7970-54b5-4040-9f20-c9959949cb84","Determination of design slamming loads on bow doors for Ro-Ro ships","Wang, Hui","","2003","","hydrodynamics","","conference paper","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:c73f39a9-2d7c-4a1c-b7ee-74b8ff90f986","http://resolver.tudelft.nl/uuid:c73f39a9-2d7c-4a1c-b7ee-74b8ff90f986","Onderbouwing van het cellenconcept Westerschelde als instrument voor beleid en beheer: Toetsing aannames met SOBEK berekeningen","Wang, Z.B.; Thoolen, P.M.C.; Tanczos, I.C.","","2002","","morfologie; morphology; onderhoudsbaggerwerken; maintenance dredging; stabiliteit; stability; vaargeulen; navigation channels; Westerschelde; Zeeland","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:ed0be7b3-5ab3-44d7-a81b-09d1bcb0188f","http://resolver.tudelft.nl/uuid:ed0be7b3-5ab3-44d7-a81b-09d1bcb0188f","ESTMORF Westerscheldeberekeningen 2002: Fase 2","Helvert, M.A.G. van; Wang, Z.B.","","2002","","Westerschelde; estuariene morfologie; estuarine morphology; morfodynamische modellen; morphodynamic models","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:36c9770b-3131-46c4-8d68-913314dfef2f","http://resolver.tudelft.nl/uuid:36c9770b-3131-46c4-8d68-913314dfef2f","Hydrology and flow forecasting","Pang, H.; Rao, S.Q.; Wang, G.Q.; Huang, X.Q.","Vrijling, J.K. (contributor); Kwadijk, J. (contributor); Van Duivendijk, J. (contributor); Van Gelder, P. (contributor)","2002","We have studied and applied the statistic model (i.e. MMC) and hydrological models to Upper Yellow River. This report introduces the results and some conclusions from the model. The three models, MMC, MWBM and NAM, have be applied in the research area. The forecasted discharge by the three models are closed to the recorded in most low flow months, but in some flood months, the forecasted value is much different with recorded one. And forecasted accuracy by MWBM nearly matches with that by NAM model. Statistical results indicate that the three models have big forecasted errors in 1989, average relative errors in the year are all excess 60%. In the other four years, MWBM and NAM models have similar forecasted errors; average relative forecasting errors fall in the range from 15% to 55%. For MMC method, average relative forecasted error in 1987 is in smallest value of 23.5% and that in 1990 is in highest value of 102.8%). Forecasted errors in the first two years are relative lower than that in the rest three years, it has increasing trendy. If acceptable forecasted result is that, relative error is less than 20% or absolute error is less than 4mm, then acceptable percentage of forecasted discharge was also calculated. Result shows that most forecasted value by MWBM and NAM is qualified. For MMC method, only in the first two years and low flow period of other years, most forecasted value is acceptable. Forecasted results by MWBM and NAM are all based on given historical meteorological data. But in real time flow forecasting, forecasting accuracy is mainly up to two factors, one is the hydrological model accuracy and the other is the meteorological forecasting accuracy. And conclusions obtained mainly reflect the first factor. In addition, in flow forecasting with the statistic method, (i.e. the MMC method), long series are mostly needed. However, 40 years is a reasonable long period of data. The forecasted error in this case is mainly due to not using the rainfall data. All of results denoted that the three models can be used to forecast discharge in the next one or two years. If meteorological data in the future can be forecasted for a longer period and are of high quality, MWBM and NAM should be adopted first.","","en","report","Delft Cluster","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:b8c41646-2dd3-4459-948a-a2b589da9bd3","http://resolver.tudelft.nl/uuid:b8c41646-2dd3-4459-948a-a2b589da9bd3","Study on mechanism for water pricing","Wang, X.W.; Gao, F.L.; Zhang, X.M.; Ruan, B.Q.","Van Beek, E. (contributor); Huisman, P. (contributor); Verhaeghe, R. (contributor); Van Duivendijk, J. (contributor)","2002","Water resources contribute greatly to human well being, both directly and indirectly. Water resources are irreplaceable natural resources, and are limited. However, due to a growing population and related economic development, the water demand from urban, industry and agriculture has increased dramatically. Water shortage has become one of the most severe problems of the Yellow River basin, and has become a major constraint for the social and economic development of the region. It is well known that water demand management methods aim at applying economic incentives to reduce the consumption of water and to encourage conservation and protection of water resources. Water pricing, an important part of demand management, has been identified as a major solution to deal with water scarcity. Water is widely recognized to be, an economic good. But, in many cases the existing price for consumers is much less than the cost of production. Because these subsidies have traditionally been in place, the water price has never been connected to the actual cost by the government or local authorities. Consequently Water pricing reforms are strongly recommended in the Yellow River basin. One of the most important issues of water pricing reform is to set a rational price. Alot of discussion is going on about how to calculate the water price and which factors should be taken into account. There are many factors playing an important role in the economic valuation of water. Besides water supply cost and operation and maintenance cost, it has to take into account such factors as the intrinsic value of water, environment effects, sustainabihty, affordability of consumers, and so on. Based on above principles, the following topics were analyzed systemically in this study. These topics included: (1) water demand management and the role of water pricing, (2) the present situation of water price system and existing problems in Yellow River basin, (3) the value of water - theory and applications in other countries, (4) full cost recovery and analysis of factors effecting the water price, (5) WRM principles and consequences for water pricing, (6) a case study on a water supply project in the Lower Yellow River, (7) legal and institutional procedures for water pricing, and finally, providing a conclusion and recommendations. This study has set up the concept of Full Cost Recovery for the pricing of water supply. Putting forward Full Cost Water Pricing should include three parts: resource cost, engineering cost and environmental cost. A theoretical framework was developed to solve the problems of the calculation of full cost water price. This theoretical framework has been applied to a case study for irrigation district on the lower Yellow River. Due to limitations of data availability, different assumptions have been made during the case study, which should be further improved and refined. With detailed field studies and data analysis, this study could be helpful for the development of the water pricing reform for the Yellow River and support YRCC in this aim to come to a more integrated management of the water resources in the basin.","water pricing; China; Yellow River","en","report","Delft Cluster","","","","","","","","Civil Engineering and Geosciences","Watermanagement","","","",""
"uuid:ec0e3eaa-39cb-41f9-be3a-a5ce735e77ac","http://resolver.tudelft.nl/uuid:ec0e3eaa-39cb-41f9-be3a-a5ce735e77ac","Quantification of Biogeomorphological Variables for Dutch Tidal Systems","Crosato, A.; Tanczos, I.; De Vries, M.; Wang, Z.B.","Deltares","2002","","estuary; geomorphology; morphodynamics","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:671ccbd3-3bdb-400b-83dc-3f92c6149a44","http://resolver.tudelft.nl/uuid:671ccbd3-3bdb-400b-83dc-3f92c6149a44","Adviezen voor het maken van een gezamenlijke zandbalans voor Westerschelde en monding","Jeuken, C.; Ruessink, G.; Wang, Z.B.","","2002","","Westerschelde; estuaria; estuaries; estuariene morfologie; estuarine morphology; baggerwerken; dredging works; zandwinning; sand dredging; vaargeulen; navigation channels","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:fc9bcc67-48db-4763-a121-86c7656099e4","http://resolver.tudelft.nl/uuid:fc9bcc67-48db-4763-a121-86c7656099e4","Coastal inlets and tidal basins","De Vriend, H.J.; Dronkers, J.; Stive, M.J.F.; Van Dongeren, A.; Wang, J.H.","","2002","lecture note: Tidal inlets and their associated basins (lagoons) are a common feature of lowland coasts all around the world. A significant part ofthe world's coastlines is formed by barrier island coasts, and most other tidal coasts are interrupted by estuaries and lagoon inlets. These tidal systems play a crucial role in the sediment budget ofthe coastal zone and thus influence the long-term coastal evolution. From a morphological point of view, tidal inlets form highly dynamical systems, which are interlinked with the adjacent coast and the tidal basin or backbarrier area to which they give access. Often, the natural morphodynamic behaviour interferes with unnatural constraints (e.g. coastal defence works) and with the effects of human utilisation (e.g. sand mining). Estuaries and tidal lagoons attract a variety of human activities, such as navigation, recreation, fishing and aquaculture, economical activity in the border zone, sand mining, land reclamation and in some cases hydrocarbon mining. On the other hand, many estuaries and lagoons form the basis of highly valuable and sometimes unique ecosystems. They function as nursery grounds for many species and as resting and feeding grounds for many others. Hence human activities which affect the properties of such a system, or put the environmental functions otherwise at risk, may have important environmental implications. For the proper management of these systems, it is therefore most important to be able to predict the impacts of such activities. At a larger scale, a deficit of sediment in the backbarrier area, due to sea level rise, for instance, can have major effects on the sediment budget of the coastal zone. The outer deltas of the inlets seem to act as sediment buffers, but the ultimate source of the sediment which goes to the backbarrier area is the coast. Since long-term coastal zone management should include sediment management, the capability to predict the large-scale exchange of sediment is of great importance to ICZM (Integrated Coastal Zone Management). The inlets and their outer deltas play a key role in this exchange. These lectures intend to develop an insight into the physical functioning of coastal inlets and tidal basins, such that possible engineering inten/entions are executed from a sustainable, holistic and integrated management perspective. The emphasis will be on inlet and basin systems which are subject to a mixed tidal and wave forcing, with negligible fresh water runoff, typical examples being the Wadden Sea and the Zeeland inlets and basins. Foreign examples are typically barrier-inlet coasts, such as found abundantly along the east-coast of the USA. This implies that fresh and salt water dynamics are not of strong relevance, and that the morphodynamics of these systems are largely determined by the interaction between the coarser sediment (fine to medium sands) and the tide and wave induced water motions.","tidal inlet; tidal basin; waddenzee; collegediktaat wa5303","en","lecture notes","TU Delft, Section Hydraulic Engineering","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:a3f9bca3-f2f2-47ef-a013-d53bec735fc6","http://resolver.tudelft.nl/uuid:a3f9bca3-f2f2-47ef-a013-d53bec735fc6","Een 1D netwerk morfodynamisch model voor het Noordelijk Deltabekken: Opzet van het model","Wang, Z.B.","","2001","","Noordelijk Deltabekken; estuariene morfologie; estuarine morphology; sedimenttransport; sediment transport; netwerken; networks","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:fb313db9-0622-44f7-9ca7-346856c8712e","http://resolver.tudelft.nl/uuid:fb313db9-0622-44f7-9ca7-346856c8712e","ESTMORF, a model for long-term morphological development of estuaries and tidal lagoons: Overall review of the development of the model","Wang, Z.B.; Helvert, M.A.G. van","","2001","","Westerschelde; estuaria; estuaries; getijdewateren; tidal waters; estuariene morfologie; estuarine morphology","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:932d7e19-8b28-4bad-9265-4075b5fdc0c4","http://resolver.tudelft.nl/uuid:932d7e19-8b28-4bad-9265-4075b5fdc0c4","A new morphological schematization of the Western Scheldt estuary, The Netherlands","Wang, Z.B.; Stive, M.J.F.; Winterwerp, J.C.; Arends, A.P.; Jeuken, C.; Kuijper, C.; Thoolen, P.M.C.","","2001","The present paper describes an analysis of the morphological integrityof the multiple channel system (MCS) of the Western Scheldt estuary. The tidal flats and surrounding ebb and flood channels form morphological cells, and the entire MCS can be schematized as a chain of such cells. The major ebb and flood channels have lost their one time function to feed and drain large tidal basins along the estuary. It is hypothesized that the MCS is now self-preserving as a result of the large gross sediment transport rates through these channels and the asymmetry of the channel system. From a stability analysis and computation of the gross sediment transports through the channels, the local and overall capacity of the estuary could be established to accommodate for the dumping of sediments dredged in the fairways of the estuary to safeguard navigation. This capacity compared favorably with the experience of the managing authorities. The scheme is used to evaluate a series of managing scenarios.","morphology; estuary; sedimentation","en","conference paper","IAHR","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:0114c410-79e8-4cc5-800f-caf30e8cdadc","http://resolver.tudelft.nl/uuid:0114c410-79e8-4cc5-800f-caf30e8cdadc","ESTMORF-model voor de Westerschelde inclusief de monding: Verbetering software en uitbreiding ; calibratie model","Wang, Z.B.; Helvert, M.A.G. van","","2001","","Westerschelde; estuaria; estuaries; getijdewateren; tidal waters; estuariene morfologie; estuarine morphology; modelijking; model calibration","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:eaaaf485-347d-4318-aa74-ecd5c6fefda3","http://resolver.tudelft.nl/uuid:eaaaf485-347d-4318-aa74-ecd5c6fefda3","Probabilistic analysis of nonlinear wave-induced loads on ships","Wang, Lihua","","2001","","scientific publications","","doctoral thesis","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:90ae3ca8-da02-42e9-9450-7c3c71860df2","http://resolver.tudelft.nl/uuid:90ae3ca8-da02-42e9-9450-7c3c71860df2","Tidal asymmetry and sediment transport in the Westerschelde estuary: A desk study","Jeuken, C.; Wang, Z.B.","","2000","","sedimenttransportmodellen; sediment transport models; sedimenttransport in estuaria; sediment transport in estuaries; getij-analyse; tidal analysis; Westerschelde","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:219fed84-a46b-4d95-a7e0-7ac955f4c926","http://resolver.tudelft.nl/uuid:219fed84-a46b-4d95-a7e0-7ac955f4c926","Verbetering weergave intergetijdegebied in ESTMORF: Implementatie van deverse maatregelen","Wang, Z.B.; Helvert, M.A.G. van","","2000","","morfodynamische modellen; morphodynamic models; modelonderzoek; modelling","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:585fa594-13ac-462b-aee5-e036c96660dd","http://resolver.tudelft.nl/uuid:585fa594-13ac-462b-aee5-e036c96660dd","Morfologische ontwikkeling van intergetijde-gebieden en modellering met ESTMORF: Literatuurstudie","Hibma, A.; Jeuken, C.; Wang, Z.B.","","2000","","morfodynamische modellen; morphodynamic models; modelonderzoek; modelling; Westerschelde; literatuuronderzoek; literature searching","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:220f16c0-30ab-44c9-b701-1a1990dc8fd5","http://resolver.tudelft.nl/uuid:220f16c0-30ab-44c9-b701-1a1990dc8fd5","Lange termijn visie Schelde-estuarium cluster morfologie: Uitvoeringsfase","Winterwerp, J.C.; Jeuken, M.C.J.L.; Helvert, M.A.G. van; Kuijper, C.; Spek, A.J.F. van der; Stive, M.J.F.; Thoolen, P.M.C.; Wang, Z.B.","","2000","","morfodynamische modellen; morphodynamic models; morfologie; morphology; riviermorfologie; river morphology; Schelde; estuaria; estuaries; onderzoek; research","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:258c2f2c-b787-4637-85b6-c3c81bd85682","http://resolver.tudelft.nl/uuid:258c2f2c-b787-4637-85b6-c3c81bd85682","Morfologische ontwikkeling van intergetijde-gebieden en modellering met ESTMORF: Evaluatie modelresultaten","Wang, Z.B.; Jeuken, C.","","2000","","modeltechniek; modelling technique; Westerschelde; morfodynamische modellen; morphodynamic models","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:50f069c1-dd52-4b9d-8b41-fbe65cfe607e","http://resolver.tudelft.nl/uuid:50f069c1-dd52-4b9d-8b41-fbe65cfe607e","Morfologie van het Noordelijk Deltabekken: Pilot toepassingen van 1D netwerk modellen SOBEK-MOR en ESTMORF","Wang, Z.B.","","2000","","morfodynamische modellen; morphodynamic models","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:8a7981e6-1767-4036-aed7-d43315db2042","http://resolver.tudelft.nl/uuid:8a7981e6-1767-4036-aed7-d43315db2042","Morfologie van het Noordelijk Deltabekken: Geschiktheid van numerieke modellen voor voorspelling van morfologische ontwikkelingen","Wang, Z.B.; Weck, A.W. van der; Houwing, E.J.","","2000","","morfodynamische modellen; morphodynamic models; Noordelijk Deltabekken","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:c2d8f053-472f-4cf1-8372-669d3133d589","http://resolver.tudelft.nl/uuid:c2d8f053-472f-4cf1-8372-669d3133d589","Convection heat losses through installation gaps between pipe and insulation and between insulation half shells","Wang, X.","","2000","","offshore","","conference paper","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:2d246ab3-c0e0-404a-84d3-3eb2d0aad75a","http://resolver.tudelft.nl/uuid:2d246ab3-c0e0-404a-84d3-3eb2d0aad75a","On advanced buckling and ultimate strength design of ship plating","Paik, Jeom Kee; Thayamballi, Anil K.; Wang, Ge; Kim, Bong Ju","","2000","","construction","","report","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:29d51baa-89da-4d9d-89a9-a67bf9f8b9ef","http://resolver.tudelft.nl/uuid:29d51baa-89da-4d9d-89a9-a67bf9f8b9ef","Prediction of vertical-plane wave loading and ship responses in high seas","Wang, Z.","","2000","","hydrodynamics","","conference paper","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:08911ef5-5ee8-4a8b-9432-5a5a5dfaa142","http://resolver.tudelft.nl/uuid:08911ef5-5ee8-4a8b-9432-5a5a5dfaa142","Tidal asymmetry and residual sediment transport in estuaries","Wang, Z.B.; Jeuken, C.; De Vriend, H.J.","Deltares","1999","Theoretical study on tidal asymmetry and application to the Westerschelde estuary.","tidal asymmetry; Westerschelde; tidal cycle; sediment transport; estuary","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:7ca91791-4857-4dee-a6ae-f7f6847ce235","http://resolver.tudelft.nl/uuid:7ca91791-4857-4dee-a6ae-f7f6847ce235","Verbetering ESTMORF","Wang, Z.B.; Bruinsma, R.","","1999","","rekenmodellen; computational models; morfodynamische modellen; morphodynamic models; estuaria; estuaries","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:e4bb58d2-864f-4941-9fd8-b87ee4368061","http://resolver.tudelft.nl/uuid:e4bb58d2-864f-4941-9fd8-b87ee4368061","Review of a scour formula","Rijn, L.C. van; Wang, Z.B.","","1999","","ontgrondingsmodellen; scour models","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:31beab81-e6d9-490b-b564-e88dd72be8af","http://resolver.tudelft.nl/uuid:31beab81-e6d9-490b-b564-e88dd72be8af","Tidal asymmetry and residual sediment transport in estuaries: A literature study and application to the Western Scheldt","Wang, Z.B.; Jeuken, C.; Vriend, H.J. de","","1999","","Westerschelde; sedimenttransport in estuaria; sediment transport in estuaries","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:9f9253a0-a05f-4fbc-acd3-0f5223bb2c7d","http://resolver.tudelft.nl/uuid:9f9253a0-a05f-4fbc-acd3-0f5223bb2c7d","Sedimenttransport modellering Westerschelde","Thoolen, P.M.C.; Wang, Z.B.","","1999","","sedimenttransportmodellen; sediment transport models; morfodynamische modellen; morphodynamic models; Westerschelde","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:a7d29ea4-8ac6-4e1d-9a6f-bc091c42cf24","http://resolver.tudelft.nl/uuid:a7d29ea4-8ac6-4e1d-9a6f-bc091c42cf24","Morfologische interpretatie van de veranderingen in het getij van de Westerschelde","Gerritsen, H.; Wang, Z.B.; Weck, A.W. van der","","1999","","morfodynamische modellen; morphodynamic models; getij-analyse; tidal analysis; Westerschelde","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:13c44b22-5446-47bc-b265-b81efd6a191d","http://resolver.tudelft.nl/uuid:13c44b22-5446-47bc-b265-b81efd6a191d","Sedimenttransport modellering Westerschelde","Thoolen, P.M.C.; Wang, Z.B.","","1999","","morfodynamische modellen; morphodynamic models; sedimenttransportmodellen; sediment transport models; Westerschelde","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:e368458c-345a-4089-aa72-721afd144b5c","http://resolver.tudelft.nl/uuid:e368458c-345a-4089-aa72-721afd144b5c","Interactions of coidal waves with cylinder arrays","Wang, K.-H.","","1999","","hydrodynamics","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:35801c24-61f9-4cf9-82c6-53bb851c1fa5","http://resolver.tudelft.nl/uuid:35801c24-61f9-4cf9-82c6-53bb851c1fa5","On the global response of a mobile offshore base","Wang, Suqin","","1999","","offshore","","conference paper","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:2ec0fdbb-0792-4ece-bdc5-5080887d478c","http://resolver.tudelft.nl/uuid:2ec0fdbb-0792-4ece-bdc5-5080887d478c","Linear and non-linear numerical seakeeping evaluation of a fast monohull ferry compared to full scale measurements","Wang, Zhaohui","","1999","","hydrodynamics","","conference paper","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:2bcf4751-0f13-49f0-989c-62ed821d2894","http://resolver.tudelft.nl/uuid:2bcf4751-0f13-49f0-989c-62ed821d2894","Verkennende studie verbetering weergave intergetijdegebied Westerschelde","Wang, Z.B.; Cloin, B.","","1999","","morfodynamische modellen; morphodynamic models; intergetijdegebieden; intertidal areas; Westerschelde","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:99ea3529-f43f-4d64-9654-0651318a3780","http://resolver.tudelft.nl/uuid:99ea3529-f43f-4d64-9654-0651318a3780","Large magnetoresistance ratio in ferromagnetic single-electron transistors in the strong tunneling regime","Wang, X.H.; Brataas, A.","","1999","","","en","journal article","American Physical Society","","","","","","","","","","","","",""
"uuid:19140979-7ed6-40ff-9733-2fcdb5a197fb","http://resolver.tudelft.nl/uuid:19140979-7ed6-40ff-9733-2fcdb5a197fb","Definitiestudie morfologische dynamiek Westerschelde","Stive, M.J.F.; Wang, Z.B.; Weck, A.W. van der; Boogaard, H.F.P. van den; Baptist, M.J.","","1998","","morfodynamica; morphodynamics; Westerschelde","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:e72461a9-45e3-483a-acc6-688bf25c0db2","http://resolver.tudelft.nl/uuid:e72461a9-45e3-483a-acc6-688bf25c0db2","Observations of shock waves in cloud cavitation","Reisman, G.E.; Wang, Y.-C.; Brennen, C.E.","","1998","","resistance & propulsion","","journal article","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:249e7413-aea2-4b75-ba05-b54abb4b70c1","http://resolver.tudelft.nl/uuid:249e7413-aea2-4b75-ba05-b54abb4b70c1","Viscoplasticity for instabilities due to strain softening and strain-rate softening","Wang, W.M.; Sluys, L.J.; De Borst, R.","","1997","","A0230 Function theory, analysis; A0260 Numerical approximation and analysis; A4630J Viscoelasticity, plasticity, viscoplasticity, creep, and stress relaxation; A4630L Buckling and instability; A6220F Deformation and plasticity; algorithmic treatment; Civil; consistency model; consistency viscoplastic approach; convergence; Duvaut Lions model; global convergence; Hardening; hardening effects; initial value problem; initial value problems; instabilities; Instability; length scales; limited numerical experience; Loading; mechanical; mechanical stability; Model; MODELS; Numerical analysis; overstress viscoplastic models; Perzyna model; plastic Deformation; Plasticity; rate dependent yield surface; regularising effect; S type instabilities; Shear; shear band; shear deformation; Softening; softening metallurgical; softening problems; standard Kuhn Tucker conditions; Stiffness; Stiffness Matrix; Strain; strain rate softening; Strain softening; Strain-softening; tangential stiffness matrix","en","journal article","Wiley","","","","","","","","","","","","",""
"uuid:9f599560-4299-4f32-a8d8-45ed5f930e10","http://resolver.tudelft.nl/uuid:9f599560-4299-4f32-a8d8-45ed5f930e10","Studie naar morfologische effecten van storten en baggeren in de Westerschelde: Ten behoeve van MER storten gebaggerd materiaal","Wang, Z.B.; Thoolen, P.M.C.; Fokkink, R.J.","","1997","","Westerschelde; baggertechniek; dredging; morfodynamische modellen; morphodynamic models; stabiliteit; stability","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:9192d789-e8b1-43f2-943e-23aaed3d895c","http://resolver.tudelft.nl/uuid:9192d789-e8b1-43f2-943e-23aaed3d895c","Morfologische interactie Westerschelde estuarium en het mondingsgebied: ASMITA-Westerschelde: een gedragsgeoriënteerde modellering","Wang, Z.B.","","1997","","Westerschelde; estuariene morfologie; estuarine morphology; estuaria; estuaries; sedimenttransport; sediment transport; zandwinning; sand dredging","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:343ad492-0b27-4109-a632-2c4bbaaf0553","http://resolver.tudelft.nl/uuid:343ad492-0b27-4109-a632-2c4bbaaf0553","Stationary and Propagative Instabilities in Metals - A Computational Point of View","Wang, W.M.","de Borst, R. (promotor)","1997","","Instabiliteiten; afschuifbanden; viscoplastische modelleringen","en","doctoral thesis","Delft University Press","","","","","","","","Civil Engineering and Geosciences","","","","",""
"uuid:49ea3510-f30c-4fdf-a805-6086ac773f0c","http://resolver.tudelft.nl/uuid:49ea3510-f30c-4fdf-a805-6086ac773f0c","Numerical stabilty analysis for free surface flows","Wang, Ming Lun; Troesch, A.W.","","1997","","hydrodynamics","","journal article","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:93ec5ed3-d647-440b-84b4-b7612ea5dc83","http://resolver.tudelft.nl/uuid:93ec5ed3-d647-440b-84b4-b7612ea5dc83","A detailed 2DH-hydrodynamic model for the Nieuwe Merwede","Wang, Z.B.; Bruinsma, R.","","1997","","Nieuwe Merwede; hydrodynamica; hydrodynamics; stromingsmodellen; flow models; Noordelijk Deltabekken; waterstanden; water levels; debiet; flow rate; stroomsnelheidsverdeling; current velocity distribution","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:32c25850-9e22-4720-9539-fc3c252511ac","http://resolver.tudelft.nl/uuid:32c25850-9e22-4720-9539-fc3c252511ac","The dynamics of microtidal lagoons and adjacent coasts","Stive, M.J.F.; Capobianco, M.; Wang, Z.B.; Ruol, P.","","1996","We have formulated an aggregated-scale behaviour-model for the interaction between a tidal basin and its adjacent coastal environment, without adopting a priory assumptions about their independent dynamic equilibrium behaviour. Necessarily so, the model combines observations and findings resuhing from analogical model applications. The model formulation is based on earlier concepts regarding the response of individual tidal system elements on a disturbance from their dynamic equilibrium state. Here, we have extended the earlier work by including interactions with the ebb-tidal delta and the directly adjacent coast. Results for schematized and real cases are discussed.","tidal inlet; tidal lagoon","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:8b8429af-8bc5-42ab-adaa-ebc74804a847","http://resolver.tudelft.nl/uuid:8b8429af-8bc5-42ab-adaa-ebc74804a847","Comparisons of two different mixed Eulerian-Lagrangian schemes based on a study of flare slamming hydrodynamics","Wang, Ming Lun; Troesch, A.W.","","1996","","hydrodynamics","","conference paper","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:76ed042a-599e-4374-9e3e-fd2a36cec229","http://resolver.tudelft.nl/uuid:76ed042a-599e-4374-9e3e-fd2a36cec229","Computational Fluid Dynamics for Chemical Reactor Engineering","Harris, C.K.; Roekaerts, D.; Rosendal, F.J.J.; Buitendijk, F.G.J.; Daskopoulos, Ph.; Vreenegoor, A.J.N.; Wang, H.","","1996","","","en","journal article","Oxford, Elsevier","","","","","","","","","","","","",""
"uuid:6a866c84-657d-4e14-a1be-cddb6f695284","http://resolver.tudelft.nl/uuid:6a866c84-657d-4e14-a1be-cddb6f695284","Verkenning naar de effecten van vaargeulverdieping in de Westerschelde op de morfologische en ecologische ontwikkelingen","Wang, Z.B.; Duel, H.; Glas, P.C.G.","","1995","","vaargeulverdieping; channel deepening; riviermorfologie; river morphology; mariene ecologie; marine ecology; hydrodynamica; hydrodynamics; estuaria; estuaries; Westerschelde","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:dc248e38-23c0-4589-a1e8-bfac9c8e341a","http://resolver.tudelft.nl/uuid:dc248e38-23c0-4589-a1e8-bfac9c8e341a","Microstructure-conductivity relationships in solid anisotropic ionically conducting materials","Butchereit, E.; Schoonman, J.; Zandbergen, H.W.; Lutz-Elsner, C.; Schreiber, M.; Wang, P.","","1995","","microstructure anisotropic ionically conducting material ionic conductor microstructure","en","conference paper","","","","","","","","","","","","","",""
"uuid:e5ad3fb5-3e8f-4349-82c0-02e3e41328db","http://resolver.tudelft.nl/uuid:e5ad3fb5-3e8f-4349-82c0-02e3e41328db","On 1D morphodynamic network models.","Fokkink, R.J. (TU Delft Applied Probability); Wang, Zhengbing (TU Delft Coastal Engineering); Schropp, M.H.I.","Grass, A.J. (editor)","1995","","","en","conference paper","","","","","","","","","","","Coastal Engineering","","",""
"uuid:fea54636-97bd-4bc9-9d96-8dcf7efb8fc6","http://resolver.tudelft.nl/uuid:fea54636-97bd-4bc9-9d96-8dcf7efb8fc6","Morphodynamic development of secondary channel systems along Rhine branches in the Netherlands","Wang, Z.B.; Kaaij, T. van der","","1994","","morfodynamica; morphodynamics; geulen; channels; riviermorfologie; river morphology; Rijn; Rhein","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:19c3ad72-afb2-408f-88a2-fce1d96d195c","http://resolver.tudelft.nl/uuid:19c3ad72-afb2-408f-88a2-fce1d96d195c","Studies on the Flow Induced by an Oscillating Airfoil in a Uniform Stream","Wang, Z.","Steketee, J.A. (promotor)","1994","","","en","doctoral thesis","Delft University Press","","","","","","","","Civil Engineering and Geosciences","","","","",""
"uuid:d88e66b7-3f1c-46aa-bfb8-056927f2f2c9","http://resolver.tudelft.nl/uuid:d88e66b7-3f1c-46aa-bfb8-056927f2f2c9","A dynamic/empirical model for the long-term morphological development of estuaries - part 1: Physical relations","Karssen, B.; Wang, Z.B.","","1993","","estuaria; estuaries; kustmorfologie; coastal morphology; estuariummodellen; estuary models","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:7410d646-92ca-46ff-9fc7-26b3a0c12e0e","http://resolver.tudelft.nl/uuid:7410d646-92ca-46ff-9fc7-26b3a0c12e0e","Theoretical analysis on nodal point relations in 1D network morphodynamic models","Wang, Z.B.; Fokkink, R.J.; Karssen, B.","","1993","","morfodynamische modellen; morphodynamic models; morfologie; morphology; netwerken; networks; estuariummodellen; estuary models; kustmorfologie; coastal morphology","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:772fa4a6-8f33-4594-9a23-75fe32fa49c5","http://resolver.tudelft.nl/uuid:772fa4a6-8f33-4594-9a23-75fe32fa49c5","Focusing grating couplers for integrated optics","Wang, C.W.","Frankena, H.J. (promotor)","1992","","","en","doctoral thesis","Delft University Press","","","","","","","","Applied Sciences","","","","",""
"uuid:00e23f2e-ff93-4fa3-b0ed-16f01b5f78bc","http://resolver.tudelft.nl/uuid:00e23f2e-ff93-4fa3-b0ed-16f01b5f78bc","Morphological modelling in estuaries and tidal inlets, part 1: Literature survey","Karssen, B.; Wang, Z.B.","","1991","","kustmorfologie; coastal morphology; numerieke modellen; numerical modelling; literatuuronderzoek; literature searching; estuariummodellen; estuary models; getij-inlaten; tidal inlets","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:0bfdbada-c63b-44e7-b804-30b7803a7c77","http://resolver.tudelft.nl/uuid:0bfdbada-c63b-44e7-b804-30b7803a7c77","Modelling of a refrigerating system coupled with a refridgerated room","Wang, H.","Stolk, A.L. (promotor)","1991","","","en","doctoral thesis","","","","","","","","","Mechanical Maritime and Materials Engineering","","","","",""
"uuid:bea91ea5-2cd0-48f6-bc56-3e9ef4c4d5a3","http://resolver.tudelft.nl/uuid:bea91ea5-2cd0-48f6-bc56-3e9ef4c4d5a3","Morphodynamic modelling for a tidal inlet in the Wadden Sea: ""Het Friesche Zeegat""","Wang, Z.B.","","1991","","kustmorfologie; coastal morphology; getij-inlaten; tidal inlets; numerieke modellen; numerical modelling; Waddenzee; Friesland","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:97f66c4b-7eed-407b-aa8f-41aa6f12c736","http://resolver.tudelft.nl/uuid:97f66c4b-7eed-407b-aa8f-41aa6f12c736","Numerical Modelling of Bay Circulation, The Sea Part 2","Wang, John D.","","1990","","hydrodynamics","","book","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:5fc9bffd-7d91-4d59-afee-9737021a2b0b","http://resolver.tudelft.nl/uuid:5fc9bffd-7d91-4d59-afee-9737021a2b0b","Mathematical modelling of morphological processes in estuaries","Wang, Z.B.","De Vries, M. (promotor); Vreugdenhil, C.B. (promotor)","1989","","","en","doctoral thesis","","","","","","","","","Civil Engineering and Geosciences","","","","",""
"uuid:e2c43d1a-0ed5-4f62-afc9-f00475aa5c88","http://resolver.tudelft.nl/uuid:e2c43d1a-0ed5-4f62-afc9-f00475aa5c88","Dynamic forces on a bed element in open channel flow with a backward facing step","Wang, X.K.","","1988","Experiments to measure forces on objects in open channel flow behind a bacward facing ste","backward facing step; open channel flow; turbulence","en","report","TU Delft","","","","","","","","Civil Engineering and Geosciences","Section Hydraulic Engineeering","","","",""
"uuid:7711a47a-df48-4207-bc9b-986a4b2ef35d","http://resolver.tudelft.nl/uuid:7711a47a-df48-4207-bc9b-986a4b2ef35d","Multiple resonances, responses, and parametric instabilities in Offshore Structures","Wu, Xiong-Jian; Wang, Yigong; Price, W.G.","","1988","","offshore","","journal article","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:20b9e3e6-99bc-4f2e-94a7-1f3effdbb77c","http://resolver.tudelft.nl/uuid:20b9e3e6-99bc-4f2e-94a7-1f3effdbb77c","Flexural response of foam-cored FRP sandwich panels","Weissman-Berman, D; Petrie, G.L.; Wang, Mo-Hwa","","1988","","construction","","conference paper","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:28a90830-b794-46d3-9d70-722493b2a714","http://resolver.tudelft.nl/uuid:28a90830-b794-46d3-9d70-722493b2a714","Laminar sidewall boundary layer in a dusty-gas shock tube","Wang, B.Y.; Glass, I.I.","","1986","","","en","report","University of Toronto","","","","","","","","","","","","",""
"uuid:ae4540ca-45b3-4a42-a3cf-a6a22a8a4f3d","http://resolver.tudelft.nl/uuid:ae4540ca-45b3-4a42-a3cf-a6a22a8a4f3d","Asymptotic solutions to compressible laminar boundary-layer equations for dusty-gas flow over a semi-infinite flat plate","Wang, B.Y.; Glass, I.I.","","1986","","","en","report","University of Toronto","","","","","","","","","","","","",""
"uuid:3363529d-04bd-4840-a4af-18640b261588","http://resolver.tudelft.nl/uuid:3363529d-04bd-4840-a4af-18640b261588","Finite-different solutions for compressible laminar boundary-layer flows of dusty gas over a semi-infinite flat plate","Wang, B.Y.; Glass, I.I.","","1986","","","en","report","University of Toronto","","","","","","","","","","","","",""
"uuid:35780c17-7469-434f-8ab2-6ca51c0ba05b","http://resolver.tudelft.nl/uuid:35780c17-7469-434f-8ab2-6ca51c0ba05b","Dynamic Behaviour of Combustible Gases Between a Shock Wave and a Following Flame","Clarke, J.F.; Wang, Z.W.","","1986","The paper describes events in time intervals up to the appearance of re-ignition of a combustible gas in the induction domain between a strong precursor shock wave and a following premixed flame. The re-ignition process takes place immediately ahead of the flame, and involves both local temperature and local pressure increases which are strongly linked to increases in precursor shock strength; the results are compatible with long-standing observations of the events known as ""explosion within the explosion"". Starting in 1946 as the College of Aeronautics, the Cranfield Institute of Technology was granted university status in 1969. In 1993 it changed its name to Cranfield University.","","en","report","Cranfield Institute of Technology","","","","","","","","","","","","",""
"uuid:3c5bed7a-ec9d-4ed9-8d69-f6c0c3eb4859","http://resolver.tudelft.nl/uuid:3c5bed7a-ec9d-4ed9-8d69-f6c0c3eb4859","A study on motions of high speed planing boats with controllable flaps in regular waves","Wang, Long-W","","1985","","hydrodynamics","","journal article","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:e062b70f-50d3-45dd-b5c8-4a54c778eb70","http://resolver.tudelft.nl/uuid:e062b70f-50d3-45dd-b5c8-4a54c778eb70","Experiments and computations on unsteady separating flow in an expanding flume","Stelling, G.S.; Wang, L.X.","","1984","An unsteady, separating flow with a free surface was investigated with a physical model and a numerical model. To simulate tidal flow, the prescribed flow rate at the inflow boundary was a half-period sine function of time. Measurements of velocities and wave heights were conducted by using LDV and a wave-height meter in a straight open channel with a sudden widening and a non-reflective outlet. Distributions of depth-averaged velocities at different times were obtained. Numerical simulation of this flow was carried out using a computer programme of second-order accuracy. The development of the recirculation region in course of time was well simulated, and the observed splitting of the main eddy in a later phase of the experiment and the secondary eddy in the concave corner were reproduced. The computational results are markedly influenced by the boundary conditions at closed boundaries and the eddy viscosity applied.","experiments; unsteady flow; separating flow; numerical model; physical model; tidal flow; boundary conditions","en","report","TU Delft, Department of Hydraulic Engineering","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:991e96ac-0d06-44ec-bcf1-c90d9ca655ca","http://resolver.tudelft.nl/uuid:991e96ac-0d06-44ec-bcf1-c90d9ca655ca","Effects of measurement error on long-term wave statistics","Le Mehaute, Bernard; Wang, Shen","","1984","","hydrodynamics","","conference paper","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:fa6394e9-4236-4bcb-807f-ce06ec4ee3c6","http://resolver.tudelft.nl/uuid:fa6394e9-4236-4bcb-807f-ce06ec4ee3c6","Measurements of turbulent flow in a suddenly expanding flume with a rough bottom","Wang, L.X.","","1983","Some measurements were conducted in a suddenly expanding flume with a rough bottom. In the approach flume, the friction velocity was determined in three ways and the distributions of turbulence intensities and Reynolds stress in a vertical were obtained. The measurement of the separating turbulent flow comprised the distribution of depth-averaged velocity and turbulence quentities (u', v', -uv and u^2 +v^2) in the separation region and the vertical distribution of turbulence quentities in the mixing layer. To measure instantaneous velocity components a Laser Doppier Velocimeter and a Data Acquisition System were employed. The data were processed using a digital filter.","expanding flume; rough bottom; suddenly expanding; seperating flow; turbulent; turbulence quentities; mixing layer","en","report","TU Delft, Department of Hydraulic Engineering","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:f4824e86-ea16-494f-b889-43ecf143eb6c","http://resolver.tudelft.nl/uuid:f4824e86-ea16-494f-b889-43ecf143eb6c","Pitch and heave characteristics of high speed planing boats","Wang, Long-W","","1983","","hydrodynamics","","report","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:2eaf8006-4272-490c-96f5-cc13e81e0550","http://resolver.tudelft.nl/uuid:2eaf8006-4272-490c-96f5-cc13e81e0550","Dynamic effects of ship passage on moored vessles","Wang, Shen","","1975","","hydrodynamics","","journal article","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:be8e0d55-4327-4828-a462-993dfc384bb3","http://resolver.tudelft.nl/uuid:be8e0d55-4327-4828-a462-993dfc384bb3","A Fortran IV program for the three dimensional steady state configuration of extensible flexible cable systems","Wang, Henry T.","","1974","","hydrodynamics","","report","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:24622048-f0f3-48ad-85ee-723896d6ebb7","http://resolver.tudelft.nl/uuid:24622048-f0f3-48ad-85ee-723896d6ebb7","Comprehensive evaluation of six thin-wing lifting surface computer programs","Wang, Henry T.","","1974","","resistance & propulsion","","report","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:055f7afd-22bf-4bc5-b841-dddf31b66217","http://resolver.tudelft.nl/uuid:055f7afd-22bf-4bc5-b841-dddf31b66217","Degree and Principal Eigenvectors in Complex Networks","Li, C.; Wang, H.; Van Mieghem, P.","","","The largest eigenvalue ? 1 of the adjacency matrix powerfully characterizes dynamic processes on networks, such as virus spread and synchronization. The minimization of the spectral radius by removing a set of links (or nodes) has been shown to be an NP-complete problem. So far, the best heuristic strategy is to remove links/nodes based on the principal eigenvector corresponding to the largest eigenvalue ? 1. This motivates us to investigate properties of the principal eigenvector x 1 and its relation with the degree vector. (a) We illustrate and explain why the average E[x 1] decreases with the linear degree correlation coefficient ? D in a network with a given degree vector; (b) The difference between the principal eigenvector and the scaled degree vector is proved to be the smallest, when ?1=N2N1 , where N k is the total number walks in the network with k hops; (c) The correlation between the principal eigenvector and the degree vector decreases when the degree correlation ? D is decreased.","networks; spectral radius; principal eigenvector; degree; as-sortativity","en","conference paper","Springer","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Network Architectures and Services Group (NAS)","","","",""
"uuid:e58d85ac-d438-4f44-bf66-d17660c532a5","http://resolver.tudelft.nl/uuid:e58d85ac-d438-4f44-bf66-d17660c532a5","HABEAS - A structural dynamics analysis system","Wang, Shou-Ling","","1970","","hydrodynamics","","report","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:0225f4ab-4565-4221-96be-4c393be526f0","http://resolver.tudelft.nl/uuid:0225f4ab-4565-4221-96be-4c393be526f0","General formulation of a peturbation theory for unsteady cavity flows","Wang, D.P.","","1965","","resistance & propulsion","","report","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""
"uuid:6deae718-b69e-4ce5-b93d-7573f9aedc35","http://resolver.tudelft.nl/uuid:6deae718-b69e-4ce5-b93d-7573f9aedc35","On the theory of the Brownian Motion II","Wang, Ming Chen","","1954","","mathematics","","book","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""