This paper presents an analysis of solar-heat driven Brayton, Rankine and Stirling cycles operating in space with different working fluids. Generation of power in space for terrestrial use can represent a great future opportunity: the low-temperature of space (~3 K), allows the attainment of very high efficiency even with low-temperature heat inputs, and the solar energy input is higher in spac...

Direct-radiator loudspeakers typically have a very low efficiency since the acoustic load on the diaphragm or cone is relatively low compared to the mechanical load, and in addition the driving mechanism of a voice coil is quite inefficient in converting electric energy into mechanical motion. The drivers have a magnetic structure that is deliberately kept mediocre so that the typical response ...

The impacts of radiative, electrical and thermal losses on the performances of nanoscale-gap thermophotovoltaic (nano-TPV) power generators consisting of a gallium antimonide cell paired with a broadband tungsten and a radiatively-optimized Drude radiator are analyzed. Results reveal that surface mode mediated nano-TPV power generation with the Drude radiator outperforms the tungsten radiator, ...

Thermal performance assessment and optimization for energy conversion utilization systems are of high significance in building efficiency. Generally speaking, the evaluation actual thermodynamic system is mainly based on First law thermodynamics, with emphasis quantity consumption, while ignoring quality. Thus, it results a one-sided analysis saving. In this paper, electricity equivalent used t...

A meso-channel parallel flow heat exchanger could be used as a radiator for fuel cell vehicles to dissipate waste heat from a fuel cell stack (FCS) to cooling air. Working fluid in tube-side channels was 50% glycol–water mixture. An experiment was conducted on an FCS radiator PFHX A with 2.685 mm hydraulic diameter meso-channels. The influences of condition parameters were analyzed. The critica...

The present work is focused on the Graphene-based nanofluids with high thermal conductivity which helps to improve performance and enhance heat transfer. systems emphasis fluid coolant selection statistical model. Graphene a super-material, lighter than air, conductivity, chemical stability. purpose of research up Nanofluids i.e., (G) oxide (GO). Nanoparticles are dispersed in base 60:40 ratio ...

A convenient mathematical formulation is given for the absolute lowfrequency response of an electrodynamic direct radiator loudspeaker mounted in a vented or unvented enclosure. The combined effects of speaker Q (ratio of reactance to resistance), enclosure size, and enclosure tuning are shown to control the convergence of the response curve towards ts asymptotic value. Mathematical criteria ar...

Noise generators are used to measure noise figure in receivers, to test system health in built-in test (BIT) circuits, in jamming, and in testing digital data transmission systems bit error rate (BER). Combining a noise generator with an antenna creates a noise radiator [1]. Such a noise radiator generates a random (non-coherent) noise field in which near-field interference is not observed. A n...