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111.
This paper presents an experimental analysis of a single pass solar air collector with, and without using baffle fin. The heat transfer coefficient between the absorber plate and air can be considerably increased by using artificial roughness on the bottom plate and under the absorber plate of a solar air heater duct. An experimental study has been conducted to investigate the effect of roughness and operating parameters on heat transfer. The investigation has covered the range of Reynolds number Re from 1259 to 2517 depending on types of the configuration of the solar collectors. Based on the experimental data, values of Nusselt number Nu have been determined for different values of configurations and operating parameters. To determine the enhancement in heat transfer and increment in thermal efficiency, the values of Nusselt have been compared with those of smooth duct under similar flow conditions. 相似文献
112.
Foued CHABANE Noureddine MOUMMI Abdelhafid BRIMA Abdelhafid MOUMMI 《Frontiers in Energy》2016,10(3):268-276
It is well known that the ambient temperature is a sensitive parameter which has a great effect on biology, technology, geology and even on human behavior. A prediction is a statement about an uncertain event. It is often, but not always, based upon experience or knowledge. Although guaranteed accurate information about the future is in many cases impossible, prediction can be useful to assist in making plans about possible developments. As a result, temperature profiles can be developed which accurately represent the expected ambient temperature exposure that this environment experiences during measurement. The ambient temperature over time is modeled based on the previous T min and T max data and using a Lagrange interpolation. To observe the comprehensive variation of ambient temperature the profile must be determined numerically. The model proposed in this paper can provide an acceptable way to measure the change in ambient temperature. 相似文献
113.
Ayat Maha Kechouane Mohamed Yaddadene Chafiaa Berouaken Malika Ayouz Katia Boarino Luca Gabouze Noureddine 《SILICON》2019,11(6):2669-2674
Silicon - Porous silicon (PSi) structures with strong hydrophobicity have been achieved by chemical etching of p-type silicon substrates in a solution based on hydrofluoric acid solution (HF) and... 相似文献
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115.
Bensabra Hakim Franczak Agnieszka Aaboubi Omar Azzouz Noureddine Chopart Jean-Paul 《Metallurgical and Materials Transactions A》2017,48(1):412-424
Metallurgical and Materials Transactions A - Several compounds tested as corrosion inhibitors have proven to possess good effectiveness in protection of steel rebar in concrete. However, most of... 相似文献
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117.
Noureddine Benkeblia Patrick Varoquaux Barbara Gouble Ghalem Selselet‐Attou 《Journal of the science of food and agriculture》2000,80(12):1772-1778
The O2 and CO2 respiration rates of untreated and irradiated onion bulbs (Allium cepa) at 0.15 and 0.30 kGy were measured at 4, 10 and 20 °C. The O2 respiration rate increased for 24 h after treatment from 0.19 mmole kg−1 h−1 at 20 °C for control samples up to 0.26 and 0.39 mmole kg−1 h−1 for 0.15 and 0.3 kGy irradiated onions respectively. Respiratory quotient (RQ) increased with temperature. The Q10 of the respiration of the control samples (1.61) was lower than that of any other plant tissue, but it increased with storage duration and irradiation dose. The respiration rate of control onions increased steadily over 25 weeks of storage at 4 °C, while that of the irradiated samples decreased during the same period after a peak observed after irradiation treatment. The apparent Km for the Menten–Michaelis equation was determined on a new respirometer and averaged 1.6 kPa at 10 °C and 6.3 kPa at 20 °C. However, at this higher temperature (20 °C) apparent Km varied with O2 partial pressure, proving that the respiration of onion bulbs does not follow a Menten–Michaelis‐like process. The Fermentative Index (FI) of onions was measured under anoxic conditions as CO2 production rates in mmole kg−1 h−1 at 4, 10 and 20 °C. © 2000 Society of Chemical Industry 相似文献
118.
Michel A. Tournour Noureddine Atalla 《International journal for numerical methods in engineering》1999,46(6):825-837
The variational boundary element method (VBEM) is widely used to compute the acoustic radiation of structures. The classical numerical implementation of the VBEM suffers from the computational cost associated with double surface integration. In a previous paper [1], the authors proposed a novel method, based on multipole expansions, to accelerate the double layer potential calculation for structures having a periodic mesh. This technique, while efficient, is still limited by the cost of computing the surface pressure from the double surface potential. This paper presents an acceleration technique, based on multipole expansion, that allies both efficiency and accuracy. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
119.
Fadi Alakhras Emna Selmane Bel Hadj Hmida Ioannis Anastopoulos Zina Trabelsi Walid Mabrouk Noureddine Ouerfelli Jean François Fauvarque 《水科学与水工程》2021,14(1):36-45
In this study, the removal of monovalent and divalent cations, Na+, K+, Mg2+, and Ca2+, in a diluted solution from Chott-El Jerid Lake, Tunisia, was investigated with the electrodialysis technique. The process was tested using two cation-exchange membranes: sulfonated polyether sulfone cross-linked with 10% hexamethylenediamine (HEXCl) and sulfonated polyether sulfone grafted with octylamine (S-PESOS). The commercially available membrane Nafion® was used for comparison. The results showed that Nafion® and S-PESOS membranes had similar removal behaviors, and the investigated cations were ranked in the following descending order in terms of their demineralization rates: Na+ > Ca2+ > Mg2+ > K+. Divalent cations were more effectively removed by HEXCl than by monovalent cations. The plots based on the Weber–Morris model showed a strong linearity. This reveals that intra-particle diffusion was not the removal rate-determining step, and the removal process was controlled by two or more concurrent mechanisms. The Boyd plots did not pass through their origin, and the sole controlling step was determined by film-diffusion resistance, especially after a long period of electrodialysis. Additionally, a semi-empirical model was established to simulate the temporal variation of the treatment process, and the physical significance and values of model parameters were compared for the three membranes. The findings of this study indicate that HEXCl and S-PESOS membranes can be efficiently utilized for water softening, especially when effluents are highly loaded with calcium and magnesium ions. 相似文献
120.