نتایج جستجو برای: quartz

تعداد نتایج: 12192  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه زنجان - دانشکده علوم انسانی 1390

چکیده منطقه مورد مطالعه بخشی از زون سنندج-سیرجان می باشد که در شمال و شمال غربی شهرستان نهاوند قرار دارد. سنگ های دگرگونی منطقه به دو گروه اصلی فلدسپات - کوارتز شیست و مرمر تقسیم می شوند. سه دسته دگرشکلی pre d1، d1 و d2، فابریک های منطقه را بوجود آورده اند. دگرشکلیpre d1 ، با دگرگونی m1 مطابقت دارد و دگرشکلی d1 دگرشکلی اصلی در منطقه است و با دگرگونی m2 هم خوانی دارد. دگرشکلی d3 به صورت ریزچین ...

2008

sq02_080825_terms_e Synthetic Quartz Crystal: A single crystal grown using the hydrothermal synthesis method. As-Grown Quartz Crystal: A synthetic quartz crystal grown naturally with no processing. Lumbered Quartz Crystal: A synthetic quartz crystal with the X and Z surfaces processed according to specified dimensions and angles using a diamond wheel #80. Y-bar Synthetic Quartz Crystal: A synth...

Journal: :Journal of occupational and environmental hygiene 2012
Gerald J Joy

Occupational exposure to high levels of respirable quartz can result in respiratory and other diseases in humans. The Mine Safety and Health Adminstration (MSHA) regulates exposure to respirable quartz in coal mines indirectly through reductions in the respirable coal mine dust exposure limit based on the content of quartz in the airborne respirable dust. This reduction is implemented when the ...

1999
Vasken Hagopian

Quartz fibers are used in high energy physics experiments as the active medium in high radiation area calorimetry. Quartz fibers are also used in the transmission of optical signals. Even though quartz does not damage by moderate amounts of irradiation, the clad of the fibers and the protective coating (buffer) do damage reducing light transmission. Various types of quartz fibers have been irra...

Journal: :The Annals of occupational hygiene 1998
B E Bang H Suhr

In this study we have measured exposure levels to quartz in different parts of the slate industry in Alta, Northern Norway. Full shift personal samples were collected from the breathing zones of outdoor and indoor workers in the slate quarries and a slate factory. The quartz content of respirable dust was between 7 and 41%. The slate factory had the lower quartz levels although 41% of total and...

Journal: :Environmental Health Perspectives 1997
V Castranova V Vallyathan D M Ramsey J L McLaurin D Pack S Leonard M W Barger J Y Ma N S Dalal A Teass

Fracturing quartz produces silica-based radicals on the fracture planes and generates hydroxyl radicals (.OH) in aqueous media. .OH production has been shown to be directly associated with quartz-induced cell damage and phagocyte activation in vitro. This .OH production in vitro is inhibited by desferrioxamine mesylate, an Fe chelator, indicating involvement of a Fenton-like reaction. Our objec...

Journal: :iranian journal of public health 0
h.dehghan shahreza n. razavizadeh

this research was conducted from july 1993 to june 1994 on the total population (711 workers) of a glass factory. the purpose of this study was to determine the quantitative free silica (quartz) in respiratory zone of workers in glass industry. field samples including 50 samples total dust and 37 samples respirable dust and standard simplex were collected on membrane filters using skc dust samp...

Journal: :The American journal of physiology 1998
Kevin E Driscoll Janet M Carter Brian W Howard Diana Hassenbein Marie Burdick Steven L Kunkel Robert M Strieter

Interleukin-10 (IL-10) can downregulate expression of several proinflammatory cytokines including chemokines. This study investigated the role of IL-10 in the acute response of the rat lung to quartz particles. Intratracheal instillation of rats with 1 mg of quartz produced an inflammatory and cytotoxic response demonstrated by increased bronchoalveolar lavage (BAL) fluid neutrophils, lactate d...

Journal: :The Annals of occupational hygiene 2002
Paul J A Borm Lang Tran

Following the classification of quartz as a human carcinogen by the IARC, many standard-setting committees are currently trying to convert this hazard into their national or EU standards. Since human data to set a safe exposure limit for quartz are limited, we hypothesized that lung burden data on quartz in coal miners' lungs after lifetime exposure could be used to set a non-carcinogenic lung ...

Journal: :ACM SIGCOMM Computer Communication Review 2015

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