نتایج جستجو برای: and gravitational acceleration effect

تعداد نتایج: 17134648  

Journal: :محیط شناسی 0
خسرو اشرفی استادیار گروه مهندسی عمران محیط زیست دانشکدۀ محیط زیست دانشگاه تهران مجید شفیع پور مطلق استادیار گروه مهندسی عمران محیط زیست دانشکدۀ محیط زیست دانشگاه تهران حدیث عباس زاده امیردهی کارشناس ارشد مهندسی عمران محیط زیست دانشکدۀ محیط زیست دانشگاه تهران

introduction air pollution has harmful effect on human health and the environment. accordingly, considerable effort has been put to analyze the air pollutants. one important issue is the spatial distribution of these pollutants. dispersion of the pollutants released from sources on the ground is mostly driven by the planetary boundary layer where turbulent flow causes mixing of the content of t...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تحصیلات تکمیلی علوم پایه زنجان - دانشکده فیزیک 1392

in the first part of this thesis we explored wetting and its dynamics for small droplets. first, we showed how a simple feature of water droplets on a surface, i.e. laplace pressure, can be exploited to build a micropump. we investigated capillary pumping in microchannels both experimentally and numerically. putting two droplets of different sizes at the in/outlet of a microchannel, will ge...

Journal: :فیزیک زمین و فضا 0
محمدعلی شریفی استادیار، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی، دانشگاه تهران، ایران عبدالرضا صفری دانشیار، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی، دانشگاه تهران، ایران بابک امجدی پرور دانشجوی کارشناسی ارشد ژئودزی، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی، دانشگاه تهران، ایران

the earth’s gravity field dedicated missions, champ, grace and goce have opened up a new era for the study of the earth’s gravity field. the missions measure different functionals on the earth’s gravitational potential which are represented in terms of the stokes coefficients or the so-called geopotential models. the mapping process of the observations into the coefficients is called recovery o...

Journal: :journal of computational applied mechanics 0
mohamad hasan rahimian دانشیار دانشکده مهندسی مکانیک دانشگاه تهران reza haghani phd student in school of mechanical eng.

in this paper the dynamic of a droplet on a surface with a hole is investigated under gravitational effect by using lattice boltzmann method. incompressible two-phase flow with high density ratio proposed by lee is considered. cahn’s theory is used to observe the wettability of the surface in contact with liquid and gas phases. several parameters such as contact angle, surface tension and gravi...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده مهندسی 1392

flow in natural river bends is a complex and turbulent phenomenon which affects the scour and sedimentations and causes an irregular bed topography on the bed. for the reason, the flow hydralics and the parameters which affect the flow to be studied and understand. in this study the effect of bed and wall roughness using the software fluent discussed in a sharp 90-degree flume bend with 40.3cm ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید چمران اهواز - دانشکده ادبیات و علوم انسانی 1390

abstract: advertisements are the most accessible type of authentic materials, and this is one reason why they are used more and more in english teaching classes. for this cause, studies in the field of advertisements are very widespread nowadays. for pun is one aspect which makes advertisements more interesting, it is used more than before in advertisements. use of puns makes an advertisement m...

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

this study attempted to explore if teaching english collocations through two different modes of awareness-raising and input flooding has any possible differential effect on immediate retention as well as retention in a delayed assessment. it also compared the possible differential effect of teaching english collocations implicitly and explicitly on actively using the items in writing. m...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهرکرد - دانشکده ادبیات و علوم انسانی 1389

current studies in second language (l2) learning have revealed the positive role of corrective feedback (cf) in both oral and written forms in different language features. the present study was an attempt to investigate the effect of both direct and indirect written corrective feedback (wcf) on the use of grammatical collocations in l2 writing. the study also sought to examine whether the effec...

2006
Robert J. Nemiroff

Are some paths and interactions immune to the gravitational curvature of spacetime? The paths of virtual particles might be – the effect is unexplored experimentally. Were a quantum theory of gravity moderated by virtual gravitons that are themselves susceptible to gravitational curvature, to obey the weak equivalence principle, and to follow null geodesics, then gravitational acceleration migh...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه یزد 1388

there is less published research about how teachers in efl contexts respond to students who are relatively less mature and less competent l2 writers. while writing researchers have examined various issues concerning peer and teacher response in writing-oriented classes, little research has centered on the effect of collaborative tasks particularly dictogloss on writing skills. output collaborat...

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