نتایج جستجو برای: rectangular and annular sections

تعداد نتایج: 16841225  

2004
M. B. Xu A. Selamet I.-J. Lee N. T. Huff

Recent improvements in fiber properties combined with their broadband acoustic dissipation characteristics make such materials potentially desirable for implementation in silencers. The acoustic modelling of simple silencer geometries, such as circular or rectangular cross-sections, has been established and classified depending on the assumption of locallyor bulk-reacting lining. Morse [1] used...

Current approach for designing of reinforced concrete members is based on the load and resistance factor. However the load and resistance parameters are random variables, the constant values have been designated for them in the designing procedure. Assuming these factors as the constants, will be led to the unsafe and uneconomical designs. Safe designing of structures requires appropriate recog...

M. H. Noroozi Moghaddam O. Rahmani,

Piezoelectric nanobeams having circular, rectangular and hexagonal cross-sections are synthesized and used in various Nano structures; however, piezoelectric nanobeams with hexagonal cross-sections have not been studied in detail. In particular, the physical mechanisms of the surface effect and the role of surface stress, surface elasticity and surface piezoelectricity have not been discussed t...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه ارومیه 1377

the methods which are used to analyze microstrip antennas, are divited into three categories: empirical methods, semi-empirical methods and full-wave analysis. empirical and semi-empirical methods are generally based on some fundamental simplifying assumptions about quality of surface current distribution and substrate thickness. thses simplificatioms cause low accuracy in field evaluation. ful...

ژورنال: علوم آب و خاک 2011
جواد فرهودی, , حسین حمیدی فر, , محمد حسین امید, ,

This paper presents the results of an analytical and experimental study on the characteristics of hydraulic jump in a triangular channel. The analytical consideration is based on the momentum conservation law for the upstream and downstream sections of the jump. The experiments were carried out in a triangular channel of glass side walls with the vertex angle of 94.4°. A wide range of discharge...

Journal: :international journal of advanced design and manufacturing technology 0
k. hoseini safari faculty of industrial and mechanical engineering, islamic azad university, qazvin branch, qazvin, iran y. mohammadi faculty of industrial and mechanical engineering, islamic azad university, qazvin branch, qazvin, iran sajjad dehghanpour department of mechanical eng., toyserkan branch, islamic azad university, toyserkan, iran

impact is one of the most important subjects which always have been considered in mechanical science. nature of impact is such that which makes its control a hard task. therefore it is required to adopt a safe and secure mechanism for transferring the impact to other vulnerable parts of a structure, when it is necessary. one of the best methods of absorbing impact energy is using thin-walled tu...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید مدنی آذربایجان - دانشکده ادبیات و علوم انسانی 1393

abstract over the past two decades, applied linguists and language teachers have shown a great deal of interest in genre-centered approaches , mainly because of pedagogic concerns . this has been due to the need to help non-native readers enhance their ability to understand academic and scientific texts. following swales’ (1981) works on genre analysis, studies of different sections of resear...

2004
A. Nouri-Borujerdi M. Layeghi

A numerical method based on the SIMPLE algorithm has been developed for the analysis of vapor flow in a concentric annular heat pipe. The steady-state response of a concentric annular heat pipe to various heat fluxes in the evaporator and condenser sections are studied. The fluid flow and heat transfer in the annular vapor space are simulated using Navier-Stokes equations. The governing equatio...

پایان نامه :دانشگاه تربیت معلم - سبزوار - دانشکده ادبیات و علوم انسانی 1391

abstract this study evaluates the iranian pre-university english textbook in terms of needs, objectives, content, and methodology. the study was designed on the qualitative- quantitative survey basis using interviews and questionnaires, a researcher-made textbook evaluation checklist and a needs analysis questionnaire. the textbook evaluation questionnaire was used in this study to elicit the ...

Journal: :Bulletin of the New Zealand Society for Earthquake Engineering 1981

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