نتایج جستجو برای: metals

تعداد نتایج: 63791  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1391

in this research we have studied the effect of some transition-metals (cu, ag and au) substitutions on two-electron reduction potential of flavins by application of dft method. all geometries have been optimized at blyp level of theory and “6-31+g** + lanl2dz” mixed basis set. the frequency job at the same method and basis sets has been performed to obtain gibbs free energy of compounds. it h...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1392

gol-e-gohar iron ore mine of sirjan in southern part of iran is a large open pit that operates below the groundwater table and during mining operation, dewatering is required to prevent operation processes from flooding. current operation is going on by digging wells in or out of the pit and pumping to prevent flooding. as a result of the former dewatering operation a vast deep cone of depressi...

2010

Ductile: Substances that can be drawn into thin wires are called ductile. For example, most of the metals are ductile. Question 2: Why is sodium kept immersed in kerosene oil? Answer: Sodium and potassium are very reactive metals and and combine explosively with air as well as water. Hence, they catch fire if kept in open. Therefore, to prevent accidental fires and accidents, sodium is stored i...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهید بهشتی - دانشکده علوم 1372

a simple, sensitive and selective method for solvent extraction and spectrophotemetric determination of lanthanum (ii) europium (iii), and cerium (iii) is described , the rare earth metals are extracted into chloroform solution of n-phenylbenzohydroxamic acid (pbha) at ph 9-10 various parameters are studied to optimize the extraction conditions. the molar absorptivity is found to increase from ...

2007
Safie Yaghoubi Janice Barlow Philip H. Kass Fern Orenstein Sandra Cross Erica Heath

.....................................................................................................................4 Introduction/Background............................................................................................... 5 Developmental Nature of Breast Cancer...........................................................................6 Sources of Metals.............................

2017
Muataz A Atieh Yun Ji Viktor Kochkodan

Journal: :تحقیقات نظام سلامت 0
حمیدرضا تشیعی دکتری مهندسی بهداشت محیط، شرکت مهندسی آب و فاضلاب کشور، تهران، ایران. مهدی حاجیان نژاد دانشیار، مرکز تحقیقات محیط زیست، دانشگاه علوم پزشکی اصفهان، اصفهان، ایران محمدمهدی امین دانشیار، مرکز تحقیقات محیط زیست، دانشگاه علوم پزشکی اصفهان، اصفهان، ایران. فرهام کرکانی کارشناس ارشد مهندسی بهداشت محیط، عضو بنیاد ملی نخبگان، تهران، ایران.

background: various chemicals are used to produce polymers ,leakage of polymer materials over the time , can cause health problems the aim of this research was to evaluate the leakage of heavy metals from the pvc and polypropylene pipes used in the water distribution system in isfahan. methods: four brands of pp pipes and two various types of pvc pipes were analyzed in this study. concentration...

Journal: :The Science of the total environment 2015
Nicola Stromsoe Samuel K Marx Hamish A McGowan Nikolaus Callow Henk Heijnis Atun Zawadzki

Industrial metals are now ubiquitous within the atmosphere and their deposition represents a potential source of contamination to surficial environments. Few studies, however, have examined the environmental fate of atmospheric industrial metals within different surface environments. In this study, patterns of accumulation of atmospherically transported industrial metals were investigated withi...

2007
M. Zeiner I. Steffan

Heavy metals in textile wastewater represent a major environmental problem, and are a potential danger to human health when present on textiles. Furthermore, the presence of some metals influences the production of textiles. Heavy metals are often used as oxidizing agents, as metal complex dyes, dye stripping agents, fastness improvers, and finishers. Thus, they act as hazardous sources through...

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