24 research outputs found

    Practical Investigation of Effectiveness of Direct Solar-Powered Air Heater

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    Solar energy is clean and available, and its use doesn\u27t hurt the environment. Heating conditioned homes and offices in wintertime deduct a large part of the amount of fuel consumed for these purposes. The use of solar radiation to heat the air proved its feasibility and usefulness and is in the research and development process and takes many forms. One of the primary types of solar air heaters is solar air heater of a transparent collector. In this study, a transparent collector solar air heater was designed and manufactured with an area of 1 m2. An aluminum plate was used to be the heating source; it takes its heat from the solar radiation. The tests results confirm the validity of this solar air heater type. The temperature of the heated air increased about 101% of the ambient air. The aluminum plate has proven to work as a source of heat

    Monopole and Berry Phase in Momentum Space in Noncommutative Quantum Mechanics

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    To build genuine generators of the rotations group in noncommutative quantum mechanics, we show that it is necessary to extend the noncommutative parameter θ\theta to a field operator, which one proves to be only momentum dependent. We find consequently that this field must be obligatorily a dual Dirac monopole in momentum space. Recent experiments in the context of the anomalous Hall effect provide for a monopole in the crystal momentum space. We suggest a connection between the noncommutative field and the Berry curvature in momentum space which is at the origine of the anomalous Hall effect.Comment: 4 page

    Noncommutative Geometry as a Regulator

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    We give a perturbative quantization of space-time R4R^4 in the case where the commutators Cμν=[Xμ,Xν]C^{{\mu}{\nu}}=[X^{\mu},X^{\nu}] of the underlying algebra generators are not central . We argue that this kind of quantum space-times can be used as regulators for quantum field theories . In particular we show in the case of the ϕ4{\phi}^4 theory that by choosing appropriately the commutators CμνC^{{\mu}{\nu}} we can remove all the infinities by reproducing all the counter terms . In other words the renormalized action on R4R^4 plus the counter terms can be rewritten as only a renormalized action on the quantum space-time QR4QR^4 . We conjecture therefore that renormalization of quantum field theory is equivalent to the quantization of the underlying space-time R4R^4 .Comment: Latex, 30 pages, no figures,typos corrected,references added . Substantial amount of rewriting of the last section . Final interesting remarks added at the end of the pape

    Exergy analysis of development on supercritical CO 2

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    Influence of Renewable Fuels and Nanoparticles Additives on Engine Performance and Soot Nanoparticles Characteristics

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    The fuel combustion in diesel engines can be improved by adding nanomaterials to the fuel which result in an reduction in pollutant emissions and enhance the quality of fuel combustion. The engine performance and soot nanoparticles characteristics were evaluated in this study with adding nanoparticles of copper oxide (CuO2) to the rapeseed methyl ester (RME) and diesel under variable engine speeds. The addition of CuO2 to the RME significantly improve brake thermal efficiency (BTE) and decline the brake specific fuel consumption (BSFC) by 23.6% and 7.6%, respectively, compared to the neat RME and diesel fuel. The inclusion CuO2 nanoparticles into the RME and diesel led to decrease the concentration and number of particulate matter (PM)by 33% and 17% in comparison with neat RME and diesel without nano additives, respectively. Moreover, PM is significantly decreased by 31.5% during the RME combustion in comparison with neat RME and diesel under various engine speeds. It was also obtained that the number of emitted particles (npo) reduced by 23.5% with adding nanoparticles to the RME in comparison with diesel, while the diameter of soot nanoparticles (dpo) increased by 8.6% in comparison with diesel. Furthermore, the addition CuO2 to the RME decreased the size and number of particles more than to the diesel fuel
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