99 research outputs found
Lectotypification and amended description of phyllanthus (phyllanthaceae) species described by koorders from sulawesi, indonesia
No full textBOUMAN, R. W., KEßLER, P. J. A. & VAN WELZEN, P. C. 2019. Lectotypification and amended description of Phyllanthus (Phyllanthaceae) species described by Koorders from Sulawesi, Indonesia. Reinwardtia 18(2): 97−103. ? Two species of Phyllanthus collected and described by Koorders during his travels on the island of Sulawesi (Indonesia) are lectotypified, descriptions amended and their taxonomic affinity is discussed. Phyllanthus mindorensis was found to be too similar to P. celebicus and is placed in the synonymy of the latter. A key is provided to the species of Phyllanthus on Sulawesi
A revised phylogenetic classification of tribe Phyllantheae (Phyllanthaceae)
No full textBouman, Roderick W., Kebler, Paul J.A., Telford, Ian R.H., Bruhl, Jeremy J., Strijk, Joeri S., Saunders, Richard M.K., Esser, Hans-Joachim, Falcón-Hidalgo, Banessa, Van, Peter C. (2022): A revised phylogenetic classification of tribe Phyllantheae (Phyllanthaceae). Phytotaxa 540 (1): 1-100, DOI: 10.11646/phytotaxa.540.1.
A Winkler Model for the Seismic Analysis of Monopile Foundations: An Exploratory Study on the Modelling of Soil-Structure Interaction during Earthquakes
No full textThe 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 foundation. The design codes do not provide a structured framework on how to deal with these uncertainties. On top of this, the design codes are for (offshore) structures in general and do not specify for the large diameter tubulars which are characteristic for the offshore wind energy sector. This thesis presents the investigation into a 1D seismic Winkler foundation that is able to represent the SSI during an earthquake. The model, a beam on nonlinear Winkler foundation (BNWF) coupled with a nonlinear ground response model, is a fast method to determine the structural response for the stochastic seismic and offshore wind load cases. Semi-empirical formulations are used to implement cyclic loading effects into the model. A 3D finite element model of an embedded monopile is developed in parallel with the seismic Winkler foundation for tuning and validation purposes. The resistance of the soil to lateral pile deflections is further investigated to address the uncertainty in the SSI. A 2D horizontal cross-section of the embedded monopile is considered to determine the linear dynamic properties (impedance) of the soil, and a plane strain finite element model is developed to investigate the effect of nonlinear soil behaviour. A combined frequency-time domain extension for the Winkler foundation is developed to incorporate the obtained frequency-dependent foundation properties into a time-domain analysis. It was found that none of the 2D analyses resulted in SSI representation that could be directly applied in a time-domain analysis. Moreover, the large D/L ratio of a monopile activates a global soil response, making an uncoupled 2D analysis inaccurate for the frequency range of interest.European Wind Energy Masters (EWEM
An FM Chirp Waveform Generator and Detector for Radar: Baseband, intermediate frequency, low noise and RF power amplifiers
No full textThis report describes the design of different amplifiers that are part of an FM transceiver. This is part of a larger project, which has the objective to design a complete FM transceiver from discrete components only, meaning that IC technology is not considered. The circuits designed are two baseband amplifiers, an intermediate frequency amplifier, a low noise amplifier and an RF power amplifier. The baseband amplifiers are implemented with a Darlington pair in common-collector configuration to achieve a high input resistance, low output resistance, and unity gain transfer. The intermediate frequency amplifier is centered at 9.95 MHz with a -3dB bandwidth of 2 MHz. The maximum gain is 40.5 dB and can be lowered with up to 39.7 dB using a potentiometer, based on the emitter degeneration principle. The low noise amplifier has a maximum noise figure of 1.4 dB over the RF carrier band of 88 to 108 MHz. It has a gain of 33 dB, and reaches its 1 dB compression point for an input of -33 dBm. The total harmonic distortion is less than 0.3%. A class E power amplifier is designed with an efficiency of 72.9%, a transmit power of 3.1 W, and a gain of 31.8 dB. Furthermore, this reports also presents a systematic design approach for amplifiers, which illustrate the core principles on which all the designs are based.Electrical Engineerin
Motion control strategies for smart floating cranes
No full textFloating structures have raised interest in the recent years for different applications, from living and farming at sea to renewable energy production. To support the logistics on the float- ing structures, floating cranes are necessary and their designs are constantly improved. In- creasing developments in the automation industry paved the way for automated crane opera- tions. In this work, motion control of a smart crane is presented with particular attention to the performance under wave motion. In this research, a scaled down, two-dimensional math- ematical model of a gantry crane is derived using Lagrangian mechanics and DC motors dy- namics. This results in a nonlinear system that is capable of simultaneous traversing and hoist- ing a container. The system is simulated in MATLAB Simulink environment and a proportional-derivative control and a state feedback control are designed and implemented. Their robustness is explored by modelling sensor behavior, external disturbances and floating platform dynamics. Both control strategies were able to keep stability in a disturbed system. During simulation, the sway angles never exceed 10 degrees. Smaller oscillations occurred us- ing the state feedback control. Therefore, it creates a smoother response compared to the pro- portional derivative control, which ultimately translates to increased safety, turnover rate and durability of the crane.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport Engineering and Logistic
Rechargeable power supply
No full textThe invention relates to a rechargeable power supply suitable to be used in a battery-operated device comprising at least one supercapacitor and at least a first and a second DC-DC converter connected in series, wherein the supercapacitor is connectable to an entry of the first DC-DC converter and the device is connectable to an exit of the second DC-DC converter.Delft University of Technolog
LECTOTYPIFICATION AND AMENDED DESCRIPTION OF PHYLLANTHUS (PHYLLANTHACEAE) SPECIES DESCRIBED BY KOORDERS FROM SULAWESI, INDONESIA
No full text
Zoetwatersituatie in de zuidwestelijke Delta
No full textIn juni 2003 heeft het Kabinet definitief besloten om de Haringvlietsluizen op een kier te zetten. In de brief waarin staatssecretaris Schultz (V&W) en minister Veerman (LNV) de provincies op de hoogte stellen staat een oproep aan de drie provincies: “De Delta kent een aantal complexe vraagstukken, die vragen om een oplossing. Het Kabinet is van mening dat het streven naar een meer natuurlijke Delta, inclusief de versterking van natuurlijke processen en het op termijn terugbrengen van getij in het Haringvliet/Hollands Diep, gekoppeld moet worden aan een meer natuurlijke, duurzame zoetwatersituatie voor de landbouw. Op basis van de visie ‘Delta in Zicht’ is een fundamentele discussie hierover in de Zeeuwse, Zuid-Hollandse en Noord-Brabantse Delta noodzakelijk. Wij achten het van groot belang dat de provincies, in samenwerking met het Rijk, het initiatief nemen om dit vraagstuk samen met andere belanghebbenden nader te verkennen”
Electric charger for an accumulator or battery
No full textThe invention relates to an electric charger for an accumulator or a battery or the like, which is adapted for rapid charging during an on-period and comprises for this purpose control means for starting and ending the on-period. The charger is provided with a circuit for converting a supply voltage to a charging current for the battery, and further with a heat-absorbing member in heat-conducting coupling with at least an electrical component of the circuit to be protected against overheating. The control means are adapted such that the on-period cannot be restarted during an off-period following the on-period. The electric charger can hereby comprise a heat-absorbing member with a relatively low heat loss, this saving space and cost.YES! DelftMechanical, Maritime and Materials Engineerin
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