نتایج جستجو برای: lack of heat exchange

تعداد نتایج: 21206659  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - پژوهشکده علوم انسانی و اجتماعی 1390

this study attempts to investigate the effect of peers’ revision in comparison to that of the teacher, and whether peers’ comments and teachers’ comments facilitate students’ revision? if yes, which one is more effective? also attempts have been made to see which aspects of language are more highlighted by peers versus teachers when commenting. besides, it is investigating the student’s attitud...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه یزد 1390

the debate whether esp teachers need to have knowledge of the specialized field they are teaching has been an issue in the literature over the last two decades. the aim of conducting this study was to explore iranian learners’ and instructors’ beliefs and attitudes concerning the role of specialized knowledge in teaching esp classes. a seventeen item questionnaire was administered to 400 esp le...

سلیمانی, محمد علی , فرجامی‌شایسته, صابر ,

In this paper, ferroelectric thin films, described by an ising model in a transverse field, have been studied under the mean-field approximation. We discuss a thin film composed of N-layer film of simple cubic symmetry with nearest-neighbor exchange in which the exchange strength and transverse field are assumed to be different from the bulk values in Ns surface layers, and we derive and illust...

       Creating full employment is one of the macroeconomic goals of politicians in all countries. Unemployment is one of the major problems facing the Iranian economy, which its reduction, requires investment in various sectors of the economy and production boom. Improving the marketing situation of agricultural products can boost production, increase income and employment in agriculture. An a...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت دبیر شهید رجایی - دانشکده علوم انسانی 1390

with the growth of more humanistic approaches towards teaching foreign languages, more emphasis has been put on learners’ feelings, emotions and individual differences. one of the issues in teaching and learning english as a foreign language is demotivation. the purpose of this study was to investigate the relationship between the components of language learning strategies, optimism, duration o...

Journal: :iranian journal of hydrogen & fuel cell 2015
mohammad alijanpour majid shateri mojtaba aghajani delavar mousa farhadi

in this research the simulation of an air independent proton exchange membrane fuel cell (pemfc) propulsion system was taken into consideration. the system consists of several parts including pem fuel cell stack, metal hydride and liquid oxygen (lox) tanks, and also pre-heaters of oxygen and hydrogen gases along with other heat exchangers, to ensure proper operation of system. the heat recovery...

2001
Martin T. Wells Sreenivasa R. Jammalamadaka Ram C. Tiwari

Let X,, , X, be a sequence of independent and identically distributed random variables with an unknown underlying continuous cumulative distribution function F. Relative to this unknown distribution function suppose one would like to test a null hypothesis concerning the goodness of fit of F to some distribution function using symmetric functions of sample spacings. In some applications the nul...

Pulsating heat pipe is an efficient heat exchange device which is being used for cooling and heating recovery. In the present work, we made a closed-loop pulsating heat pipe with six U-turns and we used water in our system. Moreover the use of water-Fe3O4 nanofluid was studied with two different filling ratios 40% and 50% and 1% mass concentration. At the end we calculated heat resistance and h...

Pulsating heat pipe is an efficient heat exchange device which is being used for cooling and heating recovery. In the present work, we made a closed-loop pulsating heat pipe with six U-turns and we used water in our system. Moreover the use of water-Fe3O4 nanofluid was studied with two different filling ratios 40% and 50% and 1% mass concentration. At the end we calculated heat resistance and h...

2002
R. MESERVEY

MESERVEY, R., 1971. The coastline fit of Africa and South America. Palaeogeography, Palaeoclimatol., Palaeoecol., 9: 233-243. It has become axiomatic that the pre-drift reconstruction of Africa and South America is to be made by fitting together the continental shelves. Although this procedure is very plausible, actually the detailed fit of the coastlines is better than that of the shelves and ...

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