Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 77 for “"energy conversion efficiency"”.
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Fabricataion of Dye Sensitized Solar Cells With Enhanced Energy Conversion Efficiency
… cheap and clean technology that harnesses solar energy efficiently and have been intensively studied. How to further decrease the production cost meanwhile enhance device performance becomes the bottleneck for DSSC commercialization. The thesis focuses on the development of new materials with the …
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The role of end-use energy conversion efficiency as a climate mitigation tool
Historically, conversion efficiency improvements have revolutionised the energy system, yet to reach climate targets, the scientific community agrees that even higher levels of energy efficiency improvement are required. When focusing on technical options there are two classes of technologies: …
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Optimizing energy conversion efficiency of a proton exchange membrane green hydrogen generation system while incorporating balance of plant modeling
… difficult to decarbonize sectors of the U.S. energy economy such as medium- and heavy-duty transportation, energy storage, and industrial processes such as steel making. Currently most of the hydrogen produced globally is produced with steam methane reforming and has a carbon intensity …
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Thermoelectric Energy Harvesting for Sensor Powering
… solved some critical issues in thermoelectric energy harvesting and tried to broaden the thermoelectric application for energy recovery and sensor powering. The scientific innovations of this dissertation were based on the new advance on thermoelectric material, device optimization, fabrication …
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Rational Design of Trimetallic Electrocatalyst for Electrochemical Overall Water Splitting
… attention due to their earth-abundancy and high efficiency. However, current bifunctional electrocatalysts suffer from the disadvantages of the complex synthetic process, low yield, or low energy conversion efficiency. Thus, it is highly desirable and significant to develop efficient …
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Harvesting photon energy : ultra-thin crystalline silicon solar cell & near-field thermoradiative cells
… sources have great potential to satisfy the energy demand of humans. This thesis studies two types of energy conversion technologies, photovoltaic solar cells based on crystalline silicon thin films and thermal-radiative cells using terrestrial heat sources, focusing on managing photons but …
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Experimental study of thermal conductivity reduction of silicon-germanium nanocomposite for thermoelastic application
To improve the thermoelectric energy conversion efficiency of silicon germanium (SiGe), two methods were used to decrease the thermal conductivity by increasing phonon boundary scattering at interfaces. In the first method, SiGe alloys were annealed at a temperature higher than the melting point to …
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Quantum efficiency and fission rate in tetracene
… fission in a photovoltaic cell, the theoretical energy conversion efficiency limit is larger than the Shockley-Queisser limit due to two excitons produced with one incident photon. In a singlet fission material, an absorbed photon excites a singlet exciton and then split into two triplet excitons …
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Quantum Coherence and Entanglement in Open Quantum Systems
… mechanism and photosynthesis–enhancing photocell efficiency via coherence.</p> <p>The radical pair mechanism used to explain the avian compass is studied in the first part. It is demonstrated that Cryptochrome is a suitable candidate of the primary magnetoreceptor, located in birds' eyes. Also, …
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Piezoelectric-based Multi-Scale Multi-Environment Energy Harvesting
Energy harvesting is a technology for generating electrical power from ambient or wasted energy. It has been investigated extensively as a means of powering small electronic devices. The recent proliferation of devices with ultra-low power consumption - devices such as RF transmitters, sensors, and …
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Defect spectroscopy on Cu(In,Ga)(S,Se) 2 -based heterojunction solar cells: role of the damp-heat treatment
… in the laboratory, leading to a reduced energy conversion efficiency. We subject non-encapsulated test cells to damp-heat exposure at 85C ambient temperature and 85% relative humidity for various time periods (6h-438h). We apply temperature-dependent capacitance-voltage measurements, …
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Silicon bottom subcell fabrication, loss analysis and shunt identification for two-terminal multijunction solar cells
… cells are a promising technology to surpass the energy-conversion efficiency of commercial single junction devices. Multijunction solar cells that integrate silicon bottom subcells could allow cost-effective efficiency enhancements and further growth in the worldwide installed photovoltaic …
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Capacitor Ladder Circuitry for Improving Electrical Energy Transfer Efficiency to Electromechanical Actuators
… on the general process of taking electrical energy from a power source to a mechanical system to do mechanical work, specifically focusing on a ladder circuit to deliver energy to a capacitive-type actuator that is modeled as a mass-spring-damper (MSD) system. The whole chain of power …
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Electromagnetic extraction and annihilation of antiprotons for spacecraft propulsion
… with relativistic corrections and variable mass-energy conversion efficiency is derived. Antimatter engines operating via the catalysis of nuclear fission in a fissile material by antiprotons are found to be three to four (3 - 4) times more efficient than traditional proton-antiproton …
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Electroluminescence characterization of organometallic perovskite solar cells
… Perovskites" which exhibit high power conversion efficiencies of approximately 23%. Aside from single-junction current-voltage characteristics, these devices exhibit low voltage light emitting diode (LED) operation with thermally activated sub-bandgap voltage turn on and efficiency …
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Thermal property of EDS film and its effect on the removal of dust particles as a function of surface temperature
Solar energy is used worldwide. Deserts and semi-arid areas are well suited for solar energy harvesting. High dust concentration in deserts, where many large solar plants are located, causes a loss of energy conversion efficiency by soiling solar collectors. Electrodynamic Screen (EDS) film when …
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Solar thermochemical conversion of CO2 into fuels using Ni-Ferrite driven redox reactions: Thermodynamic efficiency analysis
… To evaluate how different factors influence the efficiency of this process, a detailed thermodynamic model was created. This model looks at how variations in inert gas flow rates and gas-to-gas heat recuperation affect key parameters and the overall solar-to-fuel energy conversion efficiency. The …
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Design, fabrication, and performance of a gas-turbine engine from an automobile turbocharger
… cycle. Students will be able to evaluate the energy conversion efficiency and net work ratio from air temperature measurements in three stages of the cycle. The gas-turbine engine is made from an automobile turbocharger for its common shaft turbine and compressor. A combustion chamber was …
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