توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Numerical Simulation of Heat Transfer in Porous Media
اطلاعات انتشار: هفتمین همایش ملی دانشجویی مهندسی شیمی، سال
تعداد صفحات: ۷
In this article temperature distribution calculation in a porous media is considered. A tube filled with porous substance was examined by two different models. The first model is an easy one and the second one can be used successively, to get better results. This question was a combined heat transfer and fluid dynamics. In order to determine the flow rates in the channels of the second model Bernouli and continuity equation was combined. Numerical analysis using Gauss Seidel iteration and finite difference model was used to determine the temperature distribution. Two different mode of convection was examined as forced and mixed convection. The results are in the form of different graphs and figures. These results was tried to be checked by an experimental correlation and also a theoretical correlation found in the literature. These showed that the previous expectation that the second model is closer to porous media behavior was a right guess.<\div>

۲Water and thermal management in a PEM fuel cell––A parametric study
نویسنده(ها): ،
اطلاعات انتشار: دومین کنفرانس ملی هیدروژن و پیل سوختی، سال
تعداد صفحات: ۶
Non–uniform consumptions of oxygen and hydrogen in PEM fuel cells cause non–uniform current distribution and reduce the output power. In this study, a two dimensional model is proposed based on conservation laws and electrochemical equations to provide useful insights into water and heat transport mechanisms and their effects on the cell performance. The presence of liquid water in the GDL decreases the active catalyst surface which in turn degrades cell performance. The model is based on these assumptions: steady–state and isothermal cell conditions, ideal gas mixtures, isotropic diffusion media and negligible potential drop due to anode activation. The results show that inlet stoichiometry and relative humidity, inlet pressure and cell temperature are important factors that affect cell performance and the state of two phase conditions in the cathode side.<\div>

۳Investigation of the improvement sorption behavior of Zn(II) from wastewaters by bentonite as affected by solution chemistry
نویسنده(ها): ،
اطلاعات انتشار: دومین همایش ملی حفاظت و برنامه ریزی محیط زیست، سال
تعداد صفحات: ۱۱
Clay minerals have been studied extensively due to their strong sorption and complexation ability towards various environmental pollutants. Zinc is widely used in many important industrial applications such as dry battery, electroplating industry, insecticides, foundry, metallurgy, pigments and explosive manufacturing. Zinc is often found in high concentrations in wastewater from many sources, including mine drainage, galvanizing plants, pharmaceuticals production, and pigments manufacturing. Known as an inorganic pollutant of the Priority Pollutants List.In this study, the removal of zinc from wastewaters by (Na,Ca)bentonite was studied in batch technique as a function of various solution chemistry conditions such as pH, concentration of adsorbent, concentration of metal ion, stirring speed and temperature under ambient conditions.The experiments were studied using metal ion concentration of Zn(II) between 50 and 250mg L−1 at an adsorbent concentration between of 20 and 100 mgL−1. At pH 3–10, stirring speed between 500 and 1000 rpm and a temperature of 25 °C.The results show that adsorption of Zn(II) by Na–exchanged bentonite is more effective than by Ca–bentonite and the percentage of Zn(II) removal increased with increasing adsorbent concentration, contact time ,stirring speed and pH and decreased with increasing metal ion concentration<\div>

۴A Solution for OFDM using Neural Nerwork
نویسنده(ها): ،
اطلاعات انتشار: کنفرانس ملی فن آوری، انرژی و داده با رویکرد مهندسی برق و کامپیوتر، سال
تعداد صفحات: ۶
In wireless communication, reproducing of transmitted signal in receiver, using OFDM multiplexing in transmitter, can be done with neural networks. In this solution input stream canbe divided into several patterns and transmit each of them with OFDM modulator but in receiver will use a neural networkIt shall be possible with using of pattern recognition that can implement with this network. In existing OFDM receiver there isa bank of filters that reproduces the transmitted signal, but inthis text neural network shall be substituted of this receiver. Therefore it shall be designed a multilayer neural network (MLP) for this substitution in this text .The error of neural network is negligible and approximately equal to zero.<\div>

۵Design and Simulation of Microstrip Narrowband Bandpass Filter For WiMAX Application
نویسنده(ها): ،
اطلاعات انتشار: کنفرانس بین المللی یافته های نوین پژوهشی درمهندسی برق و علوم کامپیوتر، سال
تعداد صفحات: ۸
In this paper a compact narrowband band pass filter (NB BPF) with wide stop–band has been designed. The presented filter based on modified slow wave resonator of microstrip is designed to achieve narrow bandwidth. This filter has compact size, low insertion loss, high return loss and sharper selectivity in the bandpass filters.The filter has been designed for operating at center frequency 3.82 GHz with a bandwidth of 110 MHz and the fractional bandwidth is 2%, that's suitable for WiMAX applications. The measured insertion loss (s21) and return loss (s11) are –0.38 dB and –33 dB, respectively at 3.82 GHz resonant frequencies. The proposed filter is designed and simulated. The overall physical size of this filter has only been 23.9 mm * 10.2 mm or (0.41 *0.176 ).<\div>

۶Design of a sub 2dB Noise Figure Wideband LNA Using MDS Technique in CMOS Technology
اطلاعات انتشار: اولین کنفرانس بین المللی دستاوردهای نوین پژوهشی در مهندسی برق و کامپیوتر، سال
تعداد صفحات: ۵
The main purpose of this paper is to design a wide–band 3–5 GHz Low Noise Amplifier (LNA). The design begins on the schematic level where amplifier is matched to a 50 ohms termination. The match was done by lumped components. The high linearity performance is achieved by Modified Derivative Superposition (MDS) technique that reduces the third–order distortion. The proposed LNA provides an IIP3 of 38dBm, a noise figure (NF) of 1.14 dB, and power gain of 13.9 dB over the bandwidth. The power dissipation of whole proposed LNA is 6.8 mw from 1.41v and 1.15v power supplies. The design and all simulations were done using ADS (Advanced Design System).<\div>

۷Evaluating the Coconut Water as a Replacement for the Fetal Calf Serum in Cultivation of ‎Promastigotes of Leishmania Infantum
اطلاعات انتشار: International Journal of Medical Laboratory، سوم،شماره۲، ۲۰۱۶، سال
تعداد صفحات: ۶
Backgrounds and Aims: The protozoan parasites of the genus Leishmania can be stated as the causative agents of the various clinical diseases. Fetal Calf Serum (FCS) is the major part of the Leishmania culture media, which is the most expensive ingredient in these media. The coconut water is packed with nutrients that yield an array of health benefits.Materials and Methods: In the present study, the efficacy of the coconut water was evaluated in the cultivation of promastigotes of Leishmania infantum.Results: The results indicated that, the coconut water enriched with culture medium could not support the growth of the parasites and cannot be used for cultivation of Leishmania infantum.Conclusions: Leishmaniases are neglected tropical diseases that can cause human infections varying from self–healing cutaneous lesions to mucosal diffuse cutaneous and visceral forms. It is concluded that although the coconut water is an easy available and cheap replacement for FCS, it could not be used in cultivation process of Leishmania infantum promastigotes.
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