نتایج جستجو برای: acoustic properties

تعداد نتایج: 947693  

Journal: :هنرهای نمایش و موسیقی 0
امیرسهیل پیرایش فر کارشناس پلیمر، دانشکده فنی مهندسی، دانشگاه آزاد اسلامی واحد علوم و تحقیقات محمدمهدی جلیلی استادیار دانشکده فنی مهندسی، دانشگاه آزاد اسلامی واحد علوم و تحقیقات سید یحیی موسوی کارشناس پلیمر، دانشکده فنی مهندسی، دانشگاه آزاد اسلامی واحد علوم و تحقیقات

in this study, the disadvantages of wood, which is widely employed in producing music instruments, are discussed. for example, high moisture sensitivity, low impact resistance, and time-consuming procedure as well as various properties of different species or in several parts of one specimen which are the main problems of wooden music instruments are extensively discussed in this paper. many ma...

Journal: :جنگل و فرآورده های چوب 0
حوری شریف نیا دانشگاه تربیت مدرس سعید کاظمی نجفی گروه علوم و صنایع چوب و کاغذ، دانشکده منابع طبیعی ، دانشگاه تربیت مدرس مهدی احمدی نجف آبادی دانشگاه صنعتی امیر کبیر

with the aim of identifying failure mechanism in oriented strand boards, failure behavior of wood strands under tensile load was investigated using acoustic emission technique. resinated and unresinated strands were arranged at top, middle and bottom section of the board before pressing. tensile and acoustic emission tests were performed simultaneously on treated and control samples. using tens...

Monazzam, Mohammad Raza , Pirani, Marziye , Pourjandaghi, Seyed Qasem ,

Introduction: Reducing noise pollution has become an essential issue due to the increase in public concern and also social demands for a better lifestyle. Using sound absorption materials is a preferred method to reduce the noise pollution. Undesirable properties of pure polyurethane such as poor absorption of mechanical energy in narrow frequency ranges can be improved by providing polymeric n...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده مهندسی نساجی 1386

در جهان امروز منسوجات بی بافت بخش مهمی از تولیدات نساجی با کاربرد های گسترده را تشکیل داده است.از طرف دیگر آلودگی صوتی و تلاش برای مهاربیشتر آن اذهان محققان را به خود مشغول کرده است.شواهد و آمار بیانگر تمایل به استفاده روز افزون از منسوجات بی بافت به عنوان عایق های آکوستیکی می باشد .لذا آشنایی و استفاده از این محصولات در کشور ما ضروری به نظر می رسد. در این تحقیق ابتدا کاربرد های منسوجات بی باف...

In this study, the acoustic properties of porous absorbents with different porosity levels have been evaluated using different mathematical models. These models use one or more parameters of materials for calculating acoustic characteristics. In all of these models, materials are considered as equivalent fluid and reactionary characteristics have not been taken into account.

ژورنال: سلامت و محیط زیست 2020

Background and Objective: Noise pollution is one of the serious environmental issue. Sound control technologies based on sound absorption and sound insulation are considered as the two widely used methods. Therefore, the aim of this study was to modify silica aerogel nanocomposites to improve its acoustic properties. Materials and Methods:  This applied experimental research involved in examin...

Massah, H.R., Momeni-Masuleh, S.H., Setvati-Zirak, A.,

Investigating waves propagation’s equation in the atmosphere is one of the important and widely used issues in various sciences, which has attracted many researchers. A type of propagating waves is an acoustic-gravity wave. These type of waves have a lot of stationarity properties and can be propagate to a high altitude in the atmosphere. The equation of acoustic-gravity wave propagation is a h...

Journal: :journal of teaching language skills 2012
batool alinezhad elkhas vaysi

this paper aims to explore some acoustic properties (i.e. duration and pitch amplitude of speech) associated with three different emotions: anger, sadness and joy against neutrality as a reference point, all being intentionally expressed by six persian speakers. the primary purpose of this study is to find out if there is any correspondence between the given emotions and prosody patterning in p...

Journal: :زبان شناسی و گویش های خراسان 0
الخاص ویسی بتول علی ن‍ژاد

the present study provides an analysis of the correlation between acoustic properties, duration and pitch amplitude of speech associated with three basic emotions: anger, sadness and joy against neutrality as a reference, emotionally expressed by six persian speakers. rise/fall connection model (taylor, 1995) is used to analyze acoustic parameters and measure how an utterance is modulated when ...

This study aims at investigating the interface between emotion and intonation patterns (more specifically, duration and pitch amplitude of speech). To this end, the acoustic properties of spectral parameters related to speech prosody are investigated. The results of acoustic and Statistical analysis show that mean level and range of FO in the contours vary strongly as a function of the degree o...

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