Results 1 - 10 of 11444
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[en] This study emphasis the requirement of integrated approach for regulate the global temperature rises to protect the planet form climate changes and other system changes. It is clear that effect of global temperature increases, have already affected many physical and biological and human systems, This unbalances of global systems is more rapid after 1950' s increases of using environmental polluting energy sources with releasing the pollutants to global systems together with extra solar energy accumulation. How ever as a solution it is require to reduce pollutants and balance the energy level to optimum within the caring capacity. To protect the planet as a sustainable system with controlling temperature rises and other unbalances it is important to keep and protect the interrelationship of each and every system with protecting mechanisms. Therefore it is require integrated approach to establish protective mechanisms for each and every sectors of badly effecting with considering regional, national. international and global level.
[en] Heat transfer and pressure drop characteristics were numerically investigated in a corrugated plate heat exchanger, considering the operating conditions for the nuclear power system. The plate deformation which is induced by the large pressure difference between the hot fluid side and cold fluid side was examined using the two-way fluid-structure interaction (FSI), and then the friction factors and Colburn factors were investigated for the deformed geometry. The Colburn factors for the deformed geometry were similar to those of the previous correlations, while the friction factors for the deformed geometry were about 7% higher than those of the previous correlations in large pressure difference regime. (paper)
[en] This talk will present MEMS based power sources that utilize radioisotopes, solar energy, and potentially nuclear energy through advancements in integration of new structures and materials within MEMS. Micro power harvesters can harness power from vibration, radioisotopes, light, sound, and biology may provide pathways to minimize or even eliminate batteries in sensor nodes. In this talk work on radioisotope thin films for MEMS will be include the self-reciprocating cantilever, betavoltaic cells, and high DC voltages. The self-reciprocating cantilever energy harvester allows small commercially viable amounts of radioisotopes to generate mW to Watts of power so that very reliable power sources that last 100s of years are possible. The tradeoffs between reliability and potential stigma with radioisotopes allow one to span a useful design space with reliability as a key parameter. These power sources provide pulsed power at three different time scales using mechanical, RF, and static extraction of energy from collected charge. Multi-use capability, both harvesting radioisotope power and local vibration energy extends the reliability of micro-power sources further
[en] The paper assesses an innovative thermoelectric device used to generate a current by the conversion of thermal energy into electrical energy. The device has been created and verified. Until now, the efficiency of conventional thermoelectric batteries is for technical practice not sufficiently appreciated, because it does not exceed 3 %. A necessary condition needed for the implementation of the Seebeck thermoelectric effect is a sufficient and stable source of heat that provides an optimum temperature difference, but there are two other sufficient conditions for a significant increase in efficiency of thermoelectric batteries. These are concerned with the development of new materials for thermoelectric batteries and with the development of new construction of thermoelectric batteries
[en] Although there are many fluctuations in energy prices, they seems like rising day by day. Thus energy recovery systems have increasingly trend. Photovoltaic systems converts solar radiation directly into electrical energy thanks to semiconductors. But due to the nature of semiconductors, whole of solar energy cannot turn into electrical energy and the remaining energy turns into waste heat. The aim of this research is evaluate this waste heat energy by air cooling system. So, the energy efficiency of the system will be increased using appropriate heat transfer technologies such as fin, turbulator etc. (paper)
[en] We present high resolution measurements of dielectronic recombination (DR) of Fe XXII forming doubly excited Fe XXI. These measurements were performed at the Test Storage Ring (TSR) of the Max-Planck-Institute of Nuclear Physics (MPIK). Low-lying DR resonances allow precise energy determination of the doubly excited autoionising levels in Fe XXI and, with suitable future calculations of Rydberg binding energies (n ≥ 7), of 2s22p to 2s2p2 excitation energies of the boronlike Fe XXII core.
[en] In order to not further degrade the environment, people have been seeking to replace non-renewable natural resources such as fossil fuels by developing technologies that are based on renewable resources. An example of these technologies is solar energy. In this paper, we show the building and test of a solar parabolic concentrator as a prototype for the production of steam that can be coupled to a turbine to generate electricity or a steam engine in any particular industrial process.
[en] Latent heat storage systems are an effective way of storing thermal energy. Recently, phase change materials were considered also in the thermal control of compact electronic devices. In the present work a numerical and experimental investigation is presented for a solid-liquid phase change process dominated by heat conduction. In the experimental arrangement a plane slab of PCM is heated from above with an on-off thermal power simulating the behaviour of an electronic device. A two-dimensional finite volume code is used for the solution of the corresponding mathematical model. The comparison between numerical predictions and experimental data shows a good agreement. Finally, in order to characterize this thermal energy storage system, the time distribution of latent and sensible heat is analyzed.
[en] Sharing geothermal borefields is usually done with each borehole having the same inlet conditions (flow rate, temperature and fluid). The objective of this research is to improve the energy efficiency of shared and hybrid geothermal borefields by segregating heat transfer sources. Two models are briefly presented: The first model allows the segregation of the inlet conditions for each borefields; the second model allows circuits to be defined independently for each leg of double U-tubes in a borehole. An application couples residential heat pumps and arrays of solar collectors. Independent circuits configuration gave the best energy savings in a symmetric configuration, the largest shank spacing and with solar collectors functioning all year long. The boreholes have been shortened from 300 m to 150 m in this configuration. (paper)
[en] A new concept of heat exchanger at sub-millimeter scale is proposed for applications in cooling on-board electronics devices, in which the quality of the exchanges between fluid and wall is very critical. In the proposed system, the upper wall of the channel is deformed dynamically to obtain a sinusoidal wave on this surface. The lower wall is exposed to constant heat flux simulating the imprint of an electronic component. A systematic 3-D numerical study in transient regime on the different deformation parameters allowed obtaining both the pumping characteristics and the heat transfer characteristics of the system. It was observed that the dynamic deformation of the wall induces a significant pumping effect. The intensification of the heat transfer is very important even for highly degraded waveforms, although the pumping efficiency is reduced in this case. (paper)