Topic
Power density
About: Power density is a research topic. Over the lifetime, 9534 publications have been published within this topic receiving 197264 citations. The topic is also known as: volumic power & volume power density.
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TL;DR: In this article, a one-dimensional model for power transistor cooling is described and the theoretical predictions of the model are shown to be in good agreement for practical applications with three-dimensional computer simulations and experimental results.
Abstract: Differences between the measured thermal impedance of power transistors when determined by the pulsed heating curve and cooling curve techniques are discussed. These differences are shown to result primarily because the power density distributions of these devices change as devicesheat; as a result of these changes the heating curve and the cooling curve are not conjugate. It is shown that the cooling curve technique, when the cooling curve is initiated from the most non-uniform steady-state thermal, distribution, (maximum voltage, maximum power) will indicate a larger value for the thermal impedance than will the pulsed heating curve technique, even for pulses in excess of the dc power level. A one-dimensional model for power transistor cooling is described. The theoretical predictions of the model are shown to be in good agreement for practical applications with three-dimensional computer simulations and experimental results. Using this model, it is possible to estimate an average junction temperature and the area of power generation at steady-state. Both TO-66 and TO-3 encased devices of mesa and planar structures were included in this study.
95 citations
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TL;DR: In this paper, a single-chamber solid oxide fuel cells (SC-SOFCs) incorporating thin-film Sm_(0.15)Ce_( 0.85)O_(1.925) (SDC) as the electrolyte, thick Ni + SDC as the (supporting) anode and SDC + BSCF (Ba_(0., 0.5)Sr-, 0.8)Fe_(0, 3−δ)) as the cathode) were operated in a mixture of methane, oxygen and helium at furnace temperatures
95 citations
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TL;DR: GAC-ML-2CMFCs had the highest columbic efficiency and power output among all the MFCs tested, indicating that the high surface area of GAC facilitate the biofilm formation, accelerate the degradation of organic substrates, and improve power generation.
Abstract: This objective of this study is to conduct a systematic investigation of the effects of configurations, electrolyte solutions, and electrode materials on the performance of microbial fuel cells (MFC). A comparison of voltage generation, power density, and acclimation period of electrogenic bacteria was performed for a variety of MFCs. In terms of MFC configuration, membrane-less two-chamber MFCs (ML-2CMFC) had lower internal resistance, shorter acclimation period, and higher voltage generation than the conventional two-chamber MFCs (2CMFC). In terms of anode solutions (as electron donors), the two-chamber MFCs fed with anaerobic treated wastewater (AF-2CMFCs) had the power density 19 times as the two-chamber MFCs fed with acetate (NO(3)(-)2CMFCs). In terms of cathode solutions (as electron acceptors), AF-2CMFCs with ferricyanide had higher voltage generation than that of ML-2CMFCs with nitrate (NO(3)(-)ML-2CMFCs). In terms of electrode materials, ML-2CMFCs with granular-activated carbon as the electrode (GAC-ML-2CMFCs) had a power density 2.5 times as ML-2CMFCs with carbon cloth as the electrode. GAC-ML-2CMFCs had the highest columbic efficiency and power output among all the MFCs tested, indicating that the high surface area of GAC facilitate the biofilm formation, accelerate the degradation of organic substrates, and improve power generation.
94 citations
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TL;DR: It was found that the size of the as-synthesized VN/PCNPs is about 20 nm, and both r value and N2 flow rate have enormous impacts on morphology and microstructure of the nanoparticle, which correspondingly determined the electrochemical performance of the material.
Abstract: Hybrid materials of vanadium nitride and porous carbon nanoparticles (VN/PCNPs) were fabricated by a facile pyrolysis process of vanadium pentoxide (V2O5) xerogel and melamine at relatively low temperature of 800 °C for supercapacitor application. The effects of the feed ratio of V2O5 to melamine (r), and nitrogen flow rate on the microstructure and electrochemical performance were also investigated. It was found that the size of the as-synthesized nanoparticles is about 20 nm. Both r value and N2 flow rate have enormous impacts on morphology and microstructure of the nanoparticle, which correspondingly determined the electrochemical performance of the material. The VN/C hybrid nanoparticles exhibited high capacitive properties, and a maximum specific capacitance of 255.0 F g−1 was achieved at a current density of 1.0 A g−1 in 2 M KOH aqueous electrolyte and the potential range from 0 to −1.15 V. In addition, symmetrical supercapacitor fabricated with the as-synthesized VN/PCNPs presents a high specific capacitance of 43.5 F g−1 at 0.5 A g−1 based on the entire cell, and an energy density of 8.0 Wh kg−1 when the power density was 575 W kg−1. Even when the power density increased to 2831.5 W kg−1, the energy density still remained 6.1 Wh kg−1.
94 citations
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TL;DR: It is demonstrated that a small amount of nitrogen functionalization on the carbon cloth material is sufficient to enhance MFC performance, likely as a result of promoting bacterial adhesion to the surface without adversely affecting microbial viability or electron transfer to thesurface.
94 citations