نتایج جستجو برای: acoustic
تعداد نتایج: 85922 فیلتر نتایج به سال:
Abstract: Background and aims: Using water pump in residential buildings to provide the required water pressure is accompanied by noise pollution and the annoyance of residents. So, the purpose of this study is to reduce water pump noise pollution with designed acoustic curtains in a residential building of Qazvin city. Methods: The mean sound pressure level was measured before and ...
Background and aims: Development of new air pollution control techniques have always been the main concern of the researchers. The purpose of this experimental study was to investigate the effects of using acoustic fields at high sound pressure levels on the removal of sulfuric acid mist from the air stream. Methods: In this experimental study, an experimental scale agglomeration chamber was...
قابلیت استفاده از روش آکوستیک امیشن برای پایش فرآیندهای اصطکاکی به عنوان روشی تکمیلی در کنار سایر روشها مانند نیروسنجی توسط محققان متعددی مورد تأیید قرار گرفته است. در این پروژه به بررسی دقیق تر پدیده های اصطکاکی به کمک آکوستیک امیشن پرداخته می شود. شرایط تولید سیگنال های آکوستیک امیشن در شکل دهی ورق های فلزی از جمله مواردی است که مورد بررسی قرار گرفته است. برای انجام آزمایشات، سه مجموعه آزمایش...
The mathematical modeling of the acoustic wave propagation in seawater is the basis for realizing goals such as, underwater communication, seabed mapping, advanced fishing, oil and gas exploration, marine meteorology, positioning and explore the unknown targets within the water. However, due to the existence of various physical phenomena in the water environment and the various conditions gover...
One of the methods used to investigate the damaged zone in rock structure is the acoustic emission method. This method is based on receiving the elastic waves that are produced by deformation and cracking of the rock mass around the underground excavation. In this research, a study is conducted on the rock samples by a numerical method to investigate the damaged zone caused by the excavat...
Particulate separation has many applications in medicine, biology and industry. In this research, the separation of polystyrene particles with a diameter of 10, 20 and 30 μm in the fluid flow of a microchannel is investigated. The microchannel consists of a spiral region and a straight region under the influence of acoustic waves. In the spiral region, the particles under hydrodynamic effects u...
Objectives: The present study aims to compare acoustic voice parameters in patients with vocal cord nodules, polyps, and normal subjects. Methods: In this cross-sectional case-control study, the participants were selected by convenience sampling, including 30 patients with vocal polyps group, 38 patients with vocal nodules for the second group, and 42 participants without voice pathologies a...
background: organophosphorus pesticides are one of the most prevalent usages for pest control in the country. such pesticides enter into water sources by different routes. since drinking of contaminated water at the higher doses than the standard level, may causes undesirable effects to human health and ecosystem. the object of this research was to investigate the effect of various parameters...
conclusions significant difference in the fundamental frequency, jitter, shimmer, silence duration, friction duration, vocalization duration, and vocal cords contact quality index between the two groups was observed (p < 0.01). results the mean of fundamental frequency for the hearing loss children and the control group were 323.04 hz and 267.53 hz, jitter 10.05% and 1.52%, shimmer 17.24 and 5....
Introduction: In Iran country, there is a lack of reliable data on acoustic characteristics of building materials applied in the offices and industrial rooms. This study aimed to investigate noise absorption characteristics for current building and acoustics materials and provided the acoustic database. Method: In this cross sectional study, the minimum of 60 building and acoustic mate...
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