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Bradley, J.E. (author), Auping, Willem L. (author), Kleijn, René (author), Kwakkel, J.H. (author), Sprecher, Benjamin (author)Tin is an important metal for society with a high risk of supply disruptions. It is, therefore, classified as a critical material in many parts of the world. An exception is the European Union, for which tin was classified as a non-critical material in 2023. However, there are many discrepancies in the literature regarding the definitions and...journal article 2024
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Miranda Xicotencatl, Brenda (author), Kleijn, René (author), van Nielen, Sander (author), Donati, Franco (author), Sprecher, Benjamin (author), Tukker, Arnold (author)Life cycle assessment (LCA) databases and software evolve. We analyzed to which extent software and evolving life cycle inventory databases affect the comparison of technology alternatives, using a comparative LCA on permanent magnets as a case study, with two selected software tools: CMLCA and Brightway LCA. We migrated the system models...journal article 2023
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van Nielen, Sander S. (author), Sprecher, B. (author), Verhagen, Teun J. (author), Kleijn, René (author)The world is facing a growing neodymium demand, creating the need for developing a recycling system to handle future waste flows. Recycling technologies are emerging, but the recycling system around them can only be established with knowledge about available end-of-life (EoL) products. Therefore, this study quantified neodymium waste in European...journal article 2023
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Nijnens, Joey (author), Behrens, Paul (author), Kraan, Oscar (author), Sprecher, Benjamin (author), Kleijn, E.G.M. (author)Joey Nijnens holds a Master's degree in industrial ecology from Delft Technical University and Leiden University, as well as a Master's degree in supply chain management from Groningen University. He is employed at Monitor Deloitte as a strategy consultant, the strategy practice of Deloitte Consulting in the Netherlands, where he focuses on...journal article 2023
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Rozsas, Arpad (author), Slobbe, Arthur (author), Huizinga, Wyke (author), Kruithof, Maarten (author), Ajithkumar Pillai, Krishna (author), Kleijn, Kelvin (author), Giardina, Giorgia (author)This paper proposes an automated approach to predict crack pattern similarities that correlate well with assessment by structural engineers. We use Siamese convolutional neural networks (SCNN) that take two crack pattern images as inputs and output scalar similarity measures. We focus on 2D masonry facades with and without openings. The image...journal article 2022
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Deen, Aaron Doug (author), van Beusekom, Heleen M.M. (author), Pfeiffer, Tom (author), Stam, Mathijs (author), Kleijn, Dominique D.E. (author), Wentzel, Jolanda (author), Huber, Robert (author), van der Steen, A.F.W. (author), Van Soest, Gijs (author), Wang, Tianshi (author)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...journal article 2022
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Chen, Zhenyang (author), Kleijn, E.G.M. (author), Lin, H.X. (author)Wind and solar photovoltaic (PV) power form vital parts of the energy transition toward renewable energy systems. The rapid development of these two renewables represents an enormous infrastructure construction task including both power generation and its associated electrical grid systems, which will generate demand for metal resources....journal article 2022
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van As, K. (author), Dellevoet, S. F.L.J. (author), Boterman, J. (author), Kleijn, C.R. (author), Bhattacharya, N. (author), Kenjeres, S. (author)The disease atherosclerosis causes stenosis inside the patient's arteries, which often eventually turns lethal. Our goal is to detect a stenosis in a non-invasive manner, preferably in an early stage. To that end, we study whether and how laser speckle contrast imaging (LSCI) can be deployed. We start out by using computational fluid dynamics...journal article 2022
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Ebrahimi, Amin (author), Sattari, Mohammad (author), Bremer, Scholte J.L. (author), Luckabauer, Martin (author), Römer, Gert-willem R.B.E. (author), Richardson, I.M. (author), Kleijn, C.R. (author), Hermans, M.J.M. (author)The absorptivity of a material is a major uncertainty in numerical simulations of laser welding and additive manufacturing, and its value is often calibrated through trial-and-error exercises. This adversely affects the capability of numerical simulations when predicting the process behaviour and can eventually hinder the exploitation of fully...journal article 2022
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Vesper, J.E. (author), Kenjeres, S. (author), Kleijn, C.R. (author)In the present study, we propose the use of a light, inert carrier gas to support deposition uniformity and rate in continuous physical vapor deposition, in which closely spaced slots or nozzles are required to achieve a sufficiently high deposition rate. Interaction shocks between the emerging rarefied plumes cause undesired nonuniformities...journal article 2022
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Fajardo, Sebastian (author), Kleijn, Jetty (author), Takes, Frank W. (author), Langejans, G.H.J. (author)Technologies and their production systems are used by archaeologists and anthropologists to study complexity of socio-technical systems. However, there are several issues that hamper agreement about what constitutes complexity and how we can systematically compare the complexity of production systems. In this work, we propose a novel approach to...journal article 2022
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van As, K. (author), Simons, Bram A. (author), Kleijn, C.R. (author), Kenjeres, S. (author), Bhattacharya, N. (author)We study how the speckle contrast depends on scatterer velocity, with the goal of further developing laser speckle imaging as a quantitative measurement technique. To that end, we perform interferometric computer simulations on a dilute plug flow. The results of our numerical experiment, that we compare with known analytical expressions to...journal article 2022
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Ratering, Daan (author), Kleijn, W.B. (author), Gonzalez Silva, J. (author), Ferrari, Riccardo M.G. (author)Active control of noise propagating through apertures is commonly realized with closed-loop LMS algorithms. However, these algorithms require a large number of error microphones and provide only local attenuation. Slow convergence and high computational effort are additional disadvantages. We propose a wave-domain approach that converges...conference paper 2022
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Ebrahimi, Amin (author), Kleijn, C.R. (author), Hermans, M.J.M. (author), Richardson, I.M. (author)Internal flow behaviour and melt-pool surface oscillations during arc welding are complex and not yet fully understood. In the present work, high-fidelity numerical simulations are employed to describe the effects of welding position, sulphur concentration (60-300 ppm) and travel speed (1.25-5 mms-1) on molten metal flow dynamics in fully...journal article 2021
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Ebrahimi, Amin (author), Babu, A. (author), Kleijn, C.R. (author), Hermans, M.J.M. (author), Richardson, I.M. (author)One of the challenges for development, qualification and optimisation of arc welding processes lies in characterising the complex melt-pool behaviour which exhibits highly non-linear responses to variations of process parameters. The present work presents a computational model to describe the melt-pool behaviour in root-pass gas metal arc...journal article 2021
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Ebrahimi, Amin (author), Kleijn, C.R. (author), Richardson, I.M. (author)Development, optimisation and qualification of welding and additive manufacturing procedures to date have largely been undertaken on an experimental trial and error basis, which imposes significant costs. Numerical simulations are acknowledged as a promising alternative to experiments, and can improve the understanding of the complex process...journal article 2021
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Ebrahimi, Amin (author), Kleijn, C.R. (author), Richardson, I.M. (author)Molten metal melt pools are characterised by highly non-linear responses, which are very sensitive to imposed boundary conditions. Temporal and spatial variations in the energy flux distribution are often neglected in numerical simulations of melt pool behaviour. Additionally, thermo-physical properties of materials are commonly changed to...journal article 2021
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Yu, W. (author), Kleijn, W.B. (author)We describe a new method to estimate the geometry of a room and reflection coefficients given room impulse responses. The method utilizes convolutional neural networks to estimate the room geometry and multilayer perceptrons to estimate the reflection coefficients. The mean square error is used as the loss function. In contrast to existing...journal article 2021
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Shah, M.S. (author), Kleijn, C.R. (author), Kreutzer, M.T. (author), van Steijn, V. (author)The initial thickness and radius of the film that forms upon close contact of two foam bubbles are known to influence the thinning dynamics and lifetime of the film. Various scalings of lifetime tr, with initial radius Rfilm and thickness ho, have been proposed in literature. In this paper, we present a hydrodynamic thin-film model that...journal article 2021
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Pfaff, N.M. (author), Dijksman, J. A. (author), Kemperman, A. J.B. (author), van Loosdrecht, Mark C.M. (author), Kleijn, J. M. (author)Bacterial alginate-like exopolymers (ALE) gels have been used in this work as a model for the extracellular polymeric matrix of biofilms. Aim was to relate the mechanical properties and strength of this matrix that make biofilms as persistent to cleaning as they are, to the complex cohesive molecular interactions involved. Mechanical...journal article 2021