373 research outputs found
Berekening van de respons van een pijpleiding op zeegang
No full textBerekend wordt de respons van een pijpleiding op een tweedimensionaal golfveld. De invloed van kortkammigheid en de gemiddelde voortplantingsrichting van het golfveld t.o.v. de pijp wordt bepaald. De resultaten zijn numeriek uitgewerkt.VloeistofmechanicaHydraulic EngineeringCivil Engineering and Geoscience
From Si Towards SiC Technology for Harsh Environment Sensing
No full textIn the coming decade, the development in the area of More than Moore will certainly take over from Moore’s Law. Sensor development and sensor integration will prevail above lower node development. New packaging solutions will be developed which will fuel the integration of sensors. These developments can still be silicon based but where harsh environments are involved wide-bandgap (WBG) materials, such as gallium nitride (GaN) or silicon carbide (SiC), will take over the development efforts spend. In this chapter, the use of WBG SiC material is discussed and reviewed towards possible applications for sensing under harsh environment exposure.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Components, Technology and Material
Outlook: From Physics of Failure to Physics of Degradation
No full textIn the foregoing chapters, the reliability of organic compounds in microelectronics and optoelectronics was discussed. It provided a state of the art in reliability concepts for materials used in electronic products. It also enlightened the direction in reliability concepts for these products. In this chapter, we discuss the outlook where we envision that physics of failure will be replaced by physics of degradation. New technologies, like health monitoring and digital twins, are needed to make this foreseen shift in reliability concepts.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Components, Technology and Material
Degradation and Failures of Polymers Used in Light-Emitting Diodes
No full textIn this chapter, degradation mechanisms of optical materials, used in the light-emitting diode (LED)-based products, are explained. This chapter aims at describing the service conditions on the degradation mechanisms of different organic optical materials in LEDs which lead to the color shift of the light output. The contributions of different degradation mechanisms of optical and package materials in LED-based products to color shift are thoroughly explained.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Components, Technology and Material
Ultraviolet Sensing in WBG: SiC
No full textNowadays many applications require optical detection of some sorts, ranging from civil to military fields. Depending on the optical source, each sensing element needs to have distinct properties with the spectral range at the top. Choices such as sensitivity and environment play an equally important role, if not more important. The properties of the sensors can be tailored by selecting a proper material for a proper photodetector device type. The device design choice therefore will have set the performance parameters such as selectivity, sensitivity and speed. This chapter discusses such photodetection and gives requirements which need to be met. The discussion will also include the photodetection principle, device types important to this work, design considerations and relevant parameters.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Components, Technology and Material
Lightning Effects on LED-Based Luminaires
No full textThis chapter gives an extensive overview into the nature of the environment that luminaires and thus LEDs are subjected to during the event of a lightning stroke. Direct lightning stroke almost always results in instant damage for low-voltage connected devices, except in “extraordinary circumstances” where random components may survive. This is usually not a subject for debate and is not the subject of this monograph. Indirect consequences of lightning strokes, however, can be effectively mitigated as described. This chapter also delves into a realistic expected overvoltage levels for two typical systems, overhead lines and insulated cables, as obtained from lightning studies on a power network supplying power to LED devices and thus justifies the recommendations by several standards. In addition, it shows the importance of an often neglected device—MOV in mitigating attendant surges due to lightning to a level that can be withstood by LEDs and associated devices.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Components, Technology and Material
Health Monitoring for Lighting Applications
No full textTraditional lighting is focused on the prevention of hardware failures. With the trend towards controlled and connected systems, other components will start playing an equal role in the reliability of it. Here reliability needs to be replaced by availability and other modeling approaches are to be considered. System prognostics and health management is the next step to service the connected complex systems in the most effective way possible. In this chapter, we will highlight the next frontiers that will need to be taken in order to move the traditional lighting catastrophic failure thinking into a thinking more towards new ways how system (degraded) functions can fail or be compromised. Results in the failure mode of lumen maintenance and its uncertainty are presented. An industrial use case is presented demonstrating how smart lighting will eventually be able to forecast maintenance schedules more efficiently.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Components, Technology and Material
Techno-economic feasibility of Hydropower at weir-complex Driel with assessment method for low-head run-of-river powerplants
No full textThe goal of this research is to assess technical and economic feasibility of hydropower at the weir-complex of Driel. A local initiative opting to improve the environment gained interest in the idea and asked Arcadis NL for help. The weir complex at Driel lays in a key position in the Dutch river Delta and regulates the flow to the IJssel and Nederrijn, both important parts of the flood protection and important shipping routes. In the Nederrijn 2 other hydro-power plants have been built at weirs. Driel was considered as well, but at the time could not be made feasible due to the low head difference at Driel. Developments in low-head hydro-power have given new possibilities and reason for reassessment. First the location has been analysed, in particular the flow situation. Except for the low head difference, the location lends itself well for a hydroelectric plant. The crux of the research is therefore in making the most of the available head. 4 variants have been worked out: a copy of the downstream hydro-power plant of Maurik as a reference, several variations on low head Kaplan turbines and an Archimedes screw have been assessed. A special variation of the Kaplan is the Venturi enhanced Kaplan, which uses part of the discharge to increase the head difference over the turbine. To estimate the annual production, first a simple approach, assuming a turbine can create a certain head difference, and later a hydraulic model incorporating hydraulic losses and using turbomachinery theory, has been used for the Kaplan design variants. The result of the comparison is that the regular Kaplan variant number 4 with 5 turbines, a combined capacity of 3.160kW and a LCOE of 0,154 € per kWh (using interest rate of 3,3%), has the best economic performance and is therefore recommended for further development. A good second option with a lower initial investment (9,6 million euros versus 20,5 of variant nr. 4) is design variant number 1 with a set of 2 Kaplan turbines having a combined capacity of 1.475kW and a LCOE of 0,161 € per kWh. Despite the regular Kaplan performing better economically, the Venturi Enhanced Kaplan Turbine certainly has potential for low head run of river hydropower and is therefore recommended for further research as well. The increase in power and produced energy gives reason to believe that further optimisation and detailing will lead to a competitive design compared to the regular Kaplan turbines.Civil Engineering | Structural Engineering | Hydraulic Structure
Quality and Reliability in Solid-State Lighting: Qua Vadis?
No full textIn the past 4 years we have witnessed a change in quality and reliability to make the marked introduction of solid-state lighting (SSL) successful. LED penetration levels have reached values of 10–30%, depending on the application. The number and variety of LED packages and, thus, associated LED-based products, have significantly increased in the past years. Consequently, new processes and new materials are introduced which will introduce a new series of new and unknown failure modes in SSL products. The understanding of these failure modes is better understood, and the number has grown to beyond 50. The fingerprint is changing to failures that are due to interactions between components. First exercises with system level acceleration tests are presented, but it is important to derive acceleration models for these tests. Advanced reliability prediction capabilities are needed including algorithms and tools that couple the multi-physic and multiscale behavior of the SSL failure modes. The shift toward services will force the lighting industry to develop these capabilities in order to better address lifetime and reliability. Connected lighting will bring big data from live connections that can be used to determine the degradation level of the system. Both trends, service and connected, will bring yet another huge change in mind-set in the lighting industry when in concerns reliability: detailed understanding of failure mechanisms, usage scenarios, technology, and design will come together.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic Components, Technology and Material
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