Searched for: subject:"frequency"
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Gasparis, Giorgos (author)
Recently, Offshore Wind Turbines (OWT) have attracted great attention in an effort to make a shift from fossil-based energy sources towards an enhanced sustainable and renewable energy production. In order to achieve the renewables targets and reduce the cost of wind energy, OWTs are consistently increasing in size. Therefore, research has...
master thesis 2019
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de Jongh, Reinout (author)
Restrictions on NOx emissions are increasingly stricter. In order to reduce the emissions of a gas turbine, manufacturers moved from diffusion-flames to lean premixed flames in their combustion process. However lean premixed flames are prone to (transverse) combustion instabilities. These instabilities consists of thermoacoustically driven...
master thesis 2019
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Clarenburg, Jimmy (author)
Designing a controlled offshore system is a challenging process, the system dynamics are often nonlinear and subjected to loads that are random in nature. Furthermore, the proper description of the system’s dynamical behaviour involves knowledge pertaining to several fields. Unfortunately, at the design level, the process is often segregated...
master thesis 2019
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Hasper, Youri (author)
With increasing evidence of human-induced accelerated climate change, the need of sustainable, non-polluting, energy sources becomes evident. Offshore wind generated electricity is currently one of the most promising sources of energy to create a sustainable global energy mix. The offshore wind industry has developed rapidly over the last years....
master thesis 2019
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Boersma, S. (author)
Electricity consumption is increasing on a global level. In 2017, non-renewable energy sources such as crude oil, natural gas and coal provided 76% of the required energy, while 24% came from renewable sources such as hydro, wind and solar. Non-renewable sources are finite because they do not replenish rapidly enough relative to the rate at...
doctoral thesis 2019
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Wang, Kan (author), Chen, Pei (author), Teunissen, P.J.G. (author)
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...
journal article 2019
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Kementzetzidis, E. (author), Corciulo, Simone (author), Versteijlen, Willem G. (author), Pisano, F. (author)
The development of the offshore wind industry is motivating substantial research efforts worldwide, where offshore wind turbines (OWTs) of increasing size are being installed in deeper water depths. Foundation design is a major factor affecting the structural performance of OWTs, with most installations founded to date on large-diameter...
journal article 2019
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Wang, K. (author), Khodabandeh, A. (author), Teunissen, P.J.G. (author)
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...
journal article 2019
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Hendrikse, H. (author), Nord, Torodd Skjerve (author)
Interaction of sea or lake ice with vertically sided offshore structures may result in severe structural vibrations commonly referred to as ice-induced vibrations. With the surge in offshore wind developments in sub-arctic regions this problem has received increased attention over the last decade, whereas traditionally the topic has been mainly...
journal article 2019
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Chen, Y. (author), Liu, Yao-Hong (author), Zong, Z. (author), Dijkhuis, Johan (author), Dolmans, Guido (author), Staszewski, R.B. (author), Babaie, M. (author)
In this paper, we propose a method to suppress supply pushing of an LC oscillator such that it may directly operate from a switched-mode dc-dc converter generating fairly large ripples. A ripple replication block (RRB) generates an amplified ripple replica at the gate terminal of the tail current source to stabilize the oscillator's tail...
journal article 2019
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Visser, Adriaan (author)
This work determines whether the amount of frequency components present in the data can be reduced, whilst still retaining image quality, whereas most efforts in seismological research are done in reducing spatial sampling. It is shown using a PCA on the frequency spectra of several data sets that indeed a large redundancy in frequency content...
master thesis 2018
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Casacuberta Puig, J. (author), Groot, K.J. (author), Tol, H.J. (author), Hickel, S. (author)
Selective Frequency Damping (SFD) is a popular method for the computation of globally unstable steady-state solutions in fluid dynamics. The approach has two model parameters whose selection is generally unclear. In this article, a detailed analysis of the influence of these parameters is presented, answering several open questions with...
journal article 2018
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Bouman, Thijs (author)
The growing interest in the development of offshore wind farms in seismic active areas demands a better insight into the requirements earthquakes impose on the design of wind turbine foundations. The complexity of the soil-structure interaction (SSI) during an earthquake results in large uncertainties in the design process of a monopile...
master thesis 2018
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Gaida, T.C. (author), Ali, Tengku Afrizal Tengku (author), Snellen, M. (author), Amiri Simkooei, A. (author), van Dijk, T.A.G.P. (author), Simons, D.G. (author)
Multi-frequency backscatter data collected from multibeam echosounders (MBESs) is increasingly becoming available. The ability to collect data at multiple frequencies at the same time is expected to allow for better discrimination between seabed sediments. We propose an extension of the Bayesian method for seabed classification to multi...
journal article 2018
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Sattam, Ala'a (author)
The shifting of the European countries, including the Netherlands, towards an electricity production dominated by renewable energy sources to be (nearly 70%) by mid-century will have a significant impact on the frequency performance of electric networks. This would cause the level of grid inertia to be considerably reduced. From this perspective...
master thesis 2018
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Krijgsman, Wiegert (author)
In the noiseless case, the identification of a grey-box model can be posed as a feasibility problem, i.e. determining if existent - and if so - finding a parameter vector such that the parametric model equals the actual model (or its associated input-output data). Being that in this thesis we are interested in continuous-time grey-box...
master thesis 2018
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Wan, Mingyao (author)
Floating offshore solar platforms (FOSPs) are envisaged to become Ultra Large Floating Structures (ULFS) with horizontal dimensions of several kilometers. The payload of these structures comprises mainly the photovoltaic panels as well as cabling and limited electrical equipment. Thus the payload per unit area of these FOSPs is very low....
master thesis 2018
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Farhadi Machekposhti, D. (author)
Classical human-engineered transmission mechanisms such as linkages, gears, and couplings are well established designs which made out of multiple parts and rigid hinges. However, these mechanisms impose disadvantages such as wear, friction, low precision and reliability, need for assembly and lubrications, and difficulty for miniaturization. By...
doctoral thesis 2018
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Ibrahim, Raed Khalaf (author), Watson, S.J. (author), Djurović, Siniša (author), Crabtree, C.J. (author)
Determining the magnitude of particular fault signature components (FSCs) generated by wind turbine (WT) faults from current signals has been used as an effective way to detect early abnormalities. However, the WT current signals are time varying due to the constantly varying generator speed. The WT frequently operates with the generator...
journal article 2018
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Nord, Torodd S. (author), Samardžija, Ilija (author), Hendrikse, H. (author), Bjerkås, Morten (author), Høyland, Knut V. (author), Li, Hongtao (author)
The signature and occurrence of frequency lock-in (FLI) vibrations of full-scale offshore structures are not well understood. Although several structures have experienced FLI, limited amounts of time histories of the responses alongside measured met-ocean data are available in the literature. This paper presents an analysis of 61 measured...
journal article 2018
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