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- 저자 : Saeid Kheradmand (검색결과 5 건)
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Saeid Kheradmand,Mojtaba Esmailian,A. Fatahy 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.4
Finishing of a workpiece is a main process in the production. This affects the quality and lifetime. Finishing in order of nanometer, nowadays, is a main demand of the industries. Thus, some new finishing process, such as abrasive flow finishing, is introduced to respond this demand. This may be aided by rotating workpiece and imposing a magnetic field. Numerical simulation of this process can be beneficial to reduce the expense and predict the result in a minimum time. Accordingly, in this study, magnetorheological fluid finishing is numerically simulated. The working medium contains magnetic and abrasive particles, blended in a base fluid. Some hydrodynamic parameters and surface roughness variations are studied. It is found that combination of rotating a workpiece and imposing a magnetic field can improve the surface roughness up to 15 percent.
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Shabgard, Hojjat,Kheradmand, Saeid,Farzaneh, Hamed,Bae, Choongsik Elsevier 2017 Applied thermal engineering Vol.110 No.-
<P><B>Abstract</B></P> <P>A numerical model is developed to predict the performance of an exhaust gas recirculation (EGR) cooler using nanofluid as the coolant. The model accounts for turbulent flow of coolant and hot smokes on an integrated computational domain. Thermal and hydrodynamic behavior of four nanofluids comprising water as the base fluid and <SUB> SiO 2 </SUB> , <SUB> TiO 2 </SUB> , <SUB> Al 2 </SUB> <SUB> O 3 </SUB> and Cu nanoparticles, were compared over a wide range of Reynolds numbers and various particle concentrations. The accuracy of predictions was verified by experimental data available in the literature. The <SUB> Al 2 </SUB> <SUB> O 3 </SUB> - water nanofluid was found to provide the greatest heat transfer enhancement. Quantitatively, <SUB> Al 2 </SUB> <SUB> O 3 </SUB> - water nanofluid with a volume fraction of 5% and Reynolds number of 5000 improves the heat transfer coefficient by about 16% compared to pure water. However, it was found that the heat transfer enhancement was achieved at the expense of increased pressure drop due to greater viscosity of nanofluids compared to the base fluid. It was also found that the effectiveness of nanofluids in improving the heat transfer rate decreases as the Reynolds number increase.</P>
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Shabgard, Hojjat,Kheradmand, Saeid,Bae, Choongsik Professional Engineering Publishing Ltd 2014 Proceedings of the Institution of Mechanical Engin Vol. No.
<P>A three-dimensional numerical model was developed to investigate the pilot injection process in homogeneous charge compression ignition engines using the Open-FOAM computational fluid dynamics package. In particular, the percentage of trapped fuel in the crevice before the main injection was studied. The model was validated by comparing the numerically determined in-cylinder pressures with experimental data available in the literature. The amount of trapped fuel in the crevice was determined for three pilot injections at crank angles of 180°, 120° and 80° before top dead centre and for various pilot injection percentages with different swirl ratios. The results showed that the percentage and the timing of a pilot injection directly and proportionally affect the contributions due to the fuel trapped in the crevice. It was also found that the swirl ratio is an important parameter in accumulation of the fuel in the crevice.</P>
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Mohammad Nazemi Babadi,Saeid Kheradmand,배충식 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.1
In this paper, the numerical simulation of the diesel and gasoline fuels injection in a constant volume chamber and in a cylinder under the operating conditions of a compression ignition (CI) engine is conducted. The simulation results are compared with the experimental data which derived from fast imaging techniques. In order to check out the possibility of using gasoline instead of diesel to increase the volumetric efficiency of the CI engine, the spray characteristics of the gasoline and diesel with injection pressures of 40 and 80 MPa, as well as temperatures of 243, 273 and 313 K, under cold start condition is investigated. The results show that under the same conditions, the vapor penetration length for the two fuels is approximately equal and due to the lower volatility of the diesel fuel, its liquid penetration length in 40 and 80 MPa injection pressures was found to be 7 and 9 mm higher than gasoline, respectively. In addition, the reduction in fuel temperature from 313 K to 243 K leads an increase in the penetration of gasoline and diesel liquids by 12 and 10 mm, respectively. Finally, the decrease in the evaporation rate causes a non-homogeneous mixture and results an increase in the unburned hydrocarbons and emissions.
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Mahmood Moosazadeh,Roja Nikaeen,Ghasem Abedi,Motahareh Kheradmand,Saeid Safiri 질병관리본부 2016 Osong Public Health and Research Persptectives Vol.7 No.3
Objectives: Numerous studies have reported the epidemiological and clinical features of Malta fever incidence in Iran. Review and synthesis of the related literature through meta-analysis can provide an appropriate measurement for aforementioned indices. Therefore, the present study aimed to determine the epidemiological and clinical features of people with Malta fever in Iran. Methods: The required documents were obtained through searching national and international databases. In each study, standard deviation of the indices was calculated using binomial distribution formulas. Finally, the heterogeneity index was determined between studies using Cochran (Q) and I2 tests. Results: Combining the results of 47 articles in the meta-analysis indicated that 57.6% (55.02-60.1%) and 42.3% (49.8-44.9%) of the patients were male and female, respectively. Most of the patients lived in rural areas; 68.4% (63.6 -73.2%) compared to 31.4% (26.7-36.3%). In addition, 20.8% (17.4-24.2%) of the patients were ranchers and farmers, 16.9% (14.5-19.4%) were students, and 31.6% (27-36.2%) were housewives. Of the patients studies, 50.5% (35.6-65.2%) experienced contact with animals and 57.1% (46.4-67.9%) used unpasteurized dairy products. Fever, joint pain, and sweating were detected among 65.7% (53.7 -77.8%) and 55.3% (44.4-66.2%), respectively. Conclusion: The present study revealed that the frequency of male patients with brucellosis was considerably more than that of female patients. The number of patients with Malta fever in rural areas was significantly more than in urban areas. High-risk behavior, unprotected contact with animals, and using unpasteurized dairy products were among the most significant factors affecting Malta fever incidence in Iran. Fever, joint pain, and sweating were detected among most of the patients with Malta fever.
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