نتایج جستجو برای: sound and practical

تعداد نتایج: 16855817  

ژورنال: سلامت کار ایران 2018

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 ...

In consideration of physical and chemical properties of pure substances, speed of sound is one of important quantity which can used to calculate many of other thermo-physical properties such as isothermal compressibility, Joule-Thomson coefficient, isobaric heat capacity and etc. These thermo-physical properties are the main parameters in industrial and chemical processes. Development of accura...

2018
Nicole Netelenbos Robbin L. Gibb Fangfang Li Claudia L. R. Gonzalez

Executive function (EF) and language learning play a prominent role in early childhood development. Empirical research continues to point to a concurrent relation between these two faculties. What has been given little attention, however, is the association between EF and speech articulation abilities in children. This study investigated this relation in children aged 4-6 years. Significant cor...

Aerospace engines testing is a source of noise pollution and determining the low frequency acoustic characteristics of the test cell, plays an important role in optimally control of the sound field and reducing the level of sound pressure and pollution. In this study, the drop in average sound pressure level is numerically predicted by constructing a test cell according to ISO 140 standard. To ...

Barmar, Mohammad , Farhang Dehghan, Somayeh , Hajizadeh, Roohalah , Jonidi Jafari, Ahmad , Khavanin, Ali ,

Introduction: Nowadays multiple techniques have been developed to noise control. One the most important way is the control based on sound absorption and insulation. The purpose of current study was to improve the acoustic properties of soft polyurethane foam regarding combined sound absorption and insulation characteristics. Materials and Methods: Polyacrylonitrile and polyvinylidine fluoride ...

2006
Manabu Ishihara

The present in used distance education system is based on audiovisual communications. So when a teacher gives lessons to many students who are dispersed in distant places, the teacher obtains input from students through image and sound information. The students can be visually distinguished by separately displaying an active picture and a non-active background. But it is hard to distinguish the...

2006
Henry Prakken

This paper proposes an argument-based semantics for combined epistemic and practical reasoning, taking seriously the idea that in certain contexts epistemic reasoning is sceptical while practical reasoning is credulous. The new semantics combines grounded and preferred semantics. A dialectical proof theory is defined which is sound and complete with respect to this semantics and which combines ...

We investigated the issue of noise pollution in the Bidboland gas refineryby noise measurement and surveys. The Bidboland gas refinery has several process units.The sound pressure levels were measured at several places, such as units of 200, 300,400, 500, boiler, powerhouse area, cooling towers pumps, and maintenance area, and thecorresponding noise maps were produced by using sound plan softwa...

2003
Henry Prakken

This paper proposes an argument-based semantics for combined epistemic and practical reasoning, taking seriously the idea that in certain contexts epistemic reasoning is sceptical while practical reasoning is credulous. The new semantics combines grounded and preferred semantics. A dialectical proof theory is defined which is sound and complete with respect to this semantics and which combines ...

2001
P. Micheau E. Leboucher A. Berry

The active noise control of sinusoidal sound in free space has received considerable attention in the last few years. In a number of practical situations, the sound radiated in free space by extended sources needs to be globally reduced. This is the case of electrical power transformers, for example [1]. Nelson and Elliott have demonstrated that sound power attenuation can be achieved by active...

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