排序方式: 共有39条查询结果,搜索用时 15 毫秒
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Farès Tounsi Mohamed Hadj Said Ammar B. Kouki Brahim Mezghani 《Analog Integrated Circuits and Signal Processing》2017,90(3):551-562
In this paper, we aim to analyze the gain ratio in the output induced voltage of a CMOS-compatible miniaturized electrodynamic microphone which is based on the use of two coplanar concentric inductors. These latter are comparable to a concentric transformer with a secondary situated on the microphone diaphragm top. The study has been applied when the outer inductor is actuated using an AC bias instead of DC leading to a time-variable B-field. The induced output voltage expression has been evaluated using two distinct analytic methods: the magnetic field derivation and the electric field approach. When an AC current with frequency above that of the acoustic band is used to bias the primary, results show that the induced voltage increases and becomes independent from the incident pressure wave frequency. The paper demonstrates also that with an AC bias, the microphone induced voltage values can reach the order of hundreds of µVs, as opposed to only few µVs when applying a DC bias. The gain in the induced voltage has been investigated and it is shown that it can be correlated to the AC current frequency, ωc, and the inner inductor fluctuation frequency, ωp. Moreover, this has been quantified analytically and it is shown that it equals ωc/8ωp. This result will not only enhance the overall performance of the microphone, but will also make the preamplification design less complicated by increasing the SNR ratio. 相似文献
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M. A. Habib H. M. Badr S. F. Ahmed R. Ben‐Mansour K. Mezghani S. Imashuku G. J. la O' Y. Shao‐Horn N. D. Mancini A. Mitsos P. Kirchen A. F. Ghoneim 《国际能源研究杂志》2011,35(9):741-764
Fossil fuels provide a significant fraction of the global energy resources, and this is likely to remain so for several decades. Carbon dioxide (CO2) emissions have been correlated with climate change, and carbon capture is essential to enable the continuing use of fossil fuels while reducing the emissions of CO2 into the atmosphere thereby mitigating global climate changes. Among the proposed methods of CO2 capture, oxyfuel combustion technology provides a promising option, which is applicable to power generation systems. This technology is based on combustion with pure oxygen (O2) instead of air, resulting in flue gas that consists mainly of CO2 and water (H2O), that latter can be separated easily via condensation, while removing other contaminants leaving pure CO2 for storage. However, fuel combustion in pure O2 results in intolerably high combustion temperatures. In order to provide the dilution effect of the absent nitrogen (N2) and to moderate the furnace/combustor temperatures, part of the flue gas is recycled back into the combustion chamber. An efficient source of O2 is required to make oxy‐combustion a competitive CO2 capture technology. Conventional O2 production utilizing the cryogenic distillation process is energetically expensive. Ceramic membranes made from mixed ion‐electronic conducting oxides have received increasing attention because of their potential to mitigate the cost of O2 production, thus helping to promote these clean energy technologies. Some effort has also been expended in using these membranes to improve the performance of the O2 separation processes by combining air separation and high‐temperature oxidation into a single chamber. This paper provides a review of the performance of combustors utilizing oxy‐fuel combustion process, materials utilized in ion‐transport membranes and the integration of such reactors in power cycles. The review is focused on carbon capture potential, developments of oxyfuel applications and O2 separation and combustion in membrane reactors. The recent developments in oxyfuel power cycles are discussed focusing on the main concepts of manipulating exergy flows within each cycle and the reported thermal efficiencies. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Glass shaping, which corresponds to the removal of the edges of a specimen, is the last finishing operation in glass manufacturing.
This process has several functions on the final shaped glass including removing sharp edges, improving mechanical resistance,
decreasing surface damage and giving it an aesthetical aspect. This article addresses the effects of working parameters, including
grinding forces and consumed power, on surface edge finishing and damage mechanism induced during glass grinding. Microscopic
observations and multi-scale analysis have also been conducted to investigate the surface edge characteristics. Experimental
results show three damage regimes. The first (regime I) is a partial ductile regime with cutting action accompanied by chip
formation. The second (regime II) is a crushing (or fragmentation) regime. The last (regime III) is also a partial ductile
regime but by ploughing action with displaced material. The shaped surface obtained in the regime II has a better roughness
than that obtained in regime I and III. However, regimes I and III include streaks and form defects which are not present
in regime II. Similar to metallic materials, the evolution of force components show a linear relationship between normal and
tangential forces. This implicates a constant average contact pressure and friction coefficient (μ) between the flat grains and the workpiece. 相似文献
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Olfa Dabbaghi Meriem Tekaya Guido Flamini Imen Zouari Sinda El-Gharbi Naouraz M'barki Foued Laabidi Hechmi Cheheb Faouzi Attia Mouna Aïachi Mezghani Mohamed Hammami Beligh Mechri 《Journal of the American Oil Chemists' Society》2019,96(5):585-593
The main objective of this work was to study the effects of foliar biofertilizers on individual volatile profiles and phenolic compounds of olive oil (Olea europaea L. cv. Chemlali). Three foliar biofertilizers were used in two successive application seasons: T1 (rich in nitrogen, phosphorus and potassium); T2 (rich in calcium); and T3 (application of both T1 and T2). Results showed that foliar fertilization with T2 increased the phenolic compound contents (e.g., oleuropein aglycone and decarboxymethyl ligstroside aglycone) of Chemlali olive oil. It also enhanced the levels of many volatile compounds responsible for the good flavor of olive oil such as hexanal. However, T1-tested fertilizer led to a significant decrease in the content of phenolic compounds, although they seemed to improve significantly the levels of the majority of volatile compounds, especially hexanal. Based on these results, a significant relationship between plant nutrition and quality of oil was observed. Our results demonstrated a potential positive influence on the concentration of sensory quality compounds under T2 (Ca2+-based fertilizer). This result should be considered in the design of foliar nutrient application management strategies for olive trees. 相似文献
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Ines Ben Said Adele Muscolo Imed Mezghani Mohamed Chaieb 《Water and Environment Journal》2023,37(3):549-560
The increasing aridity exacerbated by climatic changes is leading to loss of perennial herbaceous plants Cenchrus ciliaris, an apomictic, polyploid grass used as forage in hot and dry areas, and is currently under threat for the increased scarcity of water. In this study, treated municipal wastewater (TWW) was used to irrigate two ploidy levels of C. ciliaris for two consecutive years. The objectives were (1) to assess the possibility of using unconventional water for watering C. ciliaris and (2) to identify at what extent TWW irrigation affected growth and nutritive properties of C. ciliaris that differed for polyploidy level. TWW irrigation positively affected growth and physiological plant parameters. In leaves of TWW watered C. ciliaris, the concentration of Nt, P and K significantly increased. The tetraploid C. ciliaris showed a better growth and quality than the hexaploid ones, appearing the most suitable cultivar to be irrigated with TWW for feed uses. In short, TWW can be strategically used for irrigating forage species with the double output of ameliorating soil properties, recovering degraded area and improving the nutritive values of fodder species contributing to the promotion of a green and sustainable circular economy, more in climatically under pressure developing countries. 相似文献