نتایج جستجو برای: which reduce their acoustic efficiency

تعداد نتایج: 5217707  

Journal: :journal of theoretical and applied vibration and acoustics 0
hossein samadiyeh earthquake research center, ferdowsi university of mashhad, iran reza khajavi earthquake research center, ferdowsi university of mashhad, iran

among different discretization approaches, finite difference method (fdm) is widely used for acoustic and elastic full-wave form modeling. an inevitable deficit of the technique, however, is its sever requirement to computational resources. a promising solution is parallelization, where the problem is broken into several segments, and the calculations are distributed over different processors. ...

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 فردوسی مشهد - دانشکده ادبیات و علوم انسانی دکتر علی شریعتی 1392

the present paper investigates how far ideologies can be tease out in discourse by examining the employed schemata by two ideologically opposed news media, the bbc and press tv, to report syria crisis during a period of nine months in 2011. by assuming that news is not a valuefree construction of facts and drawing on micro structural approach of schema theory, for the first time in discours...

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...

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

a significant problem in multicarrier communication systems is the necessity to reduce the value of papr (peak-to-average power ratio) of transmitting signal. in this thesis we study the effect of the system parameters such as coding and modulation types on papr and ultimate ber in a mc-cdma system. in this study we consider fading channel as well as the nonlinearity of transmitter’s amplifier ...

2010
Ronald K. Hanson David Davidson Xin Zhou

Motivation Fuel lean combustion is often employed to reduce pollutant emissions (CO, NOx,...) and increase gas turbine lifetime via reduced temperature. However, lean combustion is susceptible to thermoacoustic instabilities and lean blowout (LBO). Thermoacoustic instabilities are due to the coupling of heat release to acoustic oscillations, and lead to reduced combustion efficiency and increas...

2002
B. Pluymers W. Desmet D. Vandepitte P. Sas

In the automotive industry, vehicle interior acoustics has become an important design criterion. Both legal restrictions and the growing demand for comfort, force the car manufacturers to optimize the vibro-acoustic behaviour of their products. The tendency to minimise the number of physical prototypes and to reduce the overall development cost and time, as well as the high performance of moder...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سمنان - دانشکده ادبیات و علوم انسانی 1393

this thesis is an evaluation of poetry of sylvia plath (1932- 1963) and forough farrokhzad (1935-1967) using feminist approach and finds the positive concepts of hope, reason and strength through feminine images in their poetry. plath and farrokhzad are from different cultures and different countries but they share the same concepts and themes in their poetry. by applying feminist theory to the...

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