نتایج جستجو برای: profiled noise barrier

تعداد نتایج: 287161  

Journal: :international journal of environmental research 0

the paper describes an investigation about the application of the new multiple-impedance discontinuities model for optimizing profile diffuser barriers. the new multiple-impedance discontinuities model is much faster than the numerical method, thus it is used in an optimization process. the a-weighted insertion loss was used for the traffic noise spectrum. the result of optimization, which is d...

Journal: :علوم و تکنولوژی محیط زیست 0

the paper presents the results of an investigation on the acoustic performance of vertical profile parallel barriers with quadratic residue diffuser tops and faces. a 2d boundary element method (bem) was used to predict the barrier insertion loss. the results of rigid and with absorptive coverage were also calculated for comparisons. using qrd on the top surface and faces of all vertical profil...

Journal: :international journal of environmental research 2009
m.r. monazzam p. nassiri

the paper presents the results of an investigation on the acoustic performance of vertical profile parallel barriers with quadratic residue diffuser tops and faces. a 2d boundary element method (bem) is used to predict the barrier insertion loss. the results of rigid and with absorptive coverage are also calculated for comparisons. using qrd on the top surface and faces of all vertical profile ...

ژورنال: سلامت کار ایران 2009

  Background and aims   Traffic noise barriers are the most important measure to control the environmental noise pollution. Diffraction from top edge of noise barriers is the most important path of indirect sound wave moves towards receiver.Therefore, most studies are focused on  improvement of this kind.   Methods   T-shape profile barriers are one of the most successful barrier among many dif...

ژورنال: سلامت و محیط زیست 2019

Background and Objective: Efforts to improve the effectiveness of noise barriers have been made, including shape, aesthetics, form and gender. Therefore, the aim of this study was to investigate the effect of the angle upper edge in shaped noise barriers with a T-shaped upper edge. Materials and Methods: A 2D boundary element method (BEM) was used to predict the insertion loss of the tested ba...

ژورنال: سلامت و محیط زیست 2010
منظم, محمد رضا, مومن بالله فرد, سمانه, نادرزاده, مهدیه, نصیری, پروین,

Backgrounds and Objectives: There is a considerable notice in the use of noise barriers in recent years. Noise barriers as a control noise solution can increase the insertion loss to protect receivers. This paper presents the results of an investigation about the acoustic efficiency of primitive root sequence diffuser (PRD) on environmental single T-shape barrier.Materials and Methods: A 2D bou...

This paper describes an alternative finite element model that would yield more accurate results in the prediction of the behavior of Profiled Steel Sheet Dry Board (PSSDB) folded plate structures, which can be considered as an improvement of an earlier proposed model. The PSSDB folded plate structures are being proposed as an alternative to traditional forms of roof construction.The PSSDB syste...

Journal: :The Journal of the Acoustical Society of America 1991

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