نتایج جستجو برای: protective device
تعداد نتایج: 788881 فیلتر نتایج به سال:
در چند دهه اخیر توسعه مواد جاذب برای استتار تجهیزات نظامی از دید رادار پیشرفت شایان توجهی داشته است. آلاییدن فریت های هگزاگونالی با یون های مغناطیسی و غیر مغناطیسی، یکی از روش های افزایش میزان تلفات انعکاس این مواد در محدوده امواج رادار می-باشد. در این پژوهش، سه نوع فریت استرانسیوم آلاییده شده توسط یون های منگنز، تیتانیم و کبالت با فرمول شیمیایی srfe9mn1.5ti1.5o19، srfe9mn1.5co1.5o19 و srfe9co1...
Background: The occupational exposure conditions such as dust concentration, exposure time, smoking status and use of respiratory protection device are effective on pulmonary function disorder. The aim of this study was to determine the risk of pulmonary function disorder in the workers exposed to silica dust in the stone crushing by using Cox regression model. Method: 117 of workers employ...
background hearing capability plays a principal role on human's communication. noise-induced hearing loss (nihl) caused by exposure to high noise levels is a serious socio-economic problem in modern societies. nihl can either be reversible, resulting in a temporary threshold shifts (tts) or irreversible, resulting in a permanent threshold shifts (pts). pts is often confirmed in the time span of...
OBJECTIVE To determine the level of awareness and practice of use of protective eye devices among welders in Ile-Ife. METHODS This is a cross-sectional descriptive study of 405 consenting welders. A pretested proforma was utilized to obtain information on sociodemographic characteristics, as well as awareness and use of protective eye device. RESULTS The age of the respondents ranged from 1...
Disconnecting microgrid from main grid, may lead to severe frequency changes. Under frequency load shedding method provides a proper protection scheme by shedding certain amount of loads. Under frequency load shedding relay is used for frequency control of islanded microgrid. Each synchronous distributed generator (DG) of microgrid is equipped with a protective islanding detection device such a...
In this article, we present a simple, rapid prototyped polystyrene-based microfluidic device with three-dimensional (3D) interconnected microporous walls for long term perfusion cell culture. Patterned 3D interconnected microporous structures were created by a chemical treatment together with a protective mask and the native hydrophobic nature of the microporous structures were selectively made...
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