نتایج جستجو برای: nano chromium

تعداد نتایج: 73427  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی خواجه نصیرالدین طوسی 1390

فرآیند ماشینکاری به روش تخلیه الکتریکی( edm)، یکی از فرآیندهای نوین ماشینکاری است که کاربردهای متنوعی در ساخت و تولید محصولات میکرومتری دارد. رشد و توسعه نانوتکنولوژی و نیاز به بهره گیری از روشهای جدید موجب شده است که جذبه زیادی برای استفاده از فرآیند edm در ساخت و تولید محصولات نانومتری ایجاد شود. فرآیند nano-edm یک فرآیند ماشینکاری حرارتی است که در آن از انرژی حرارتی حاصل از جرقه الکتریکی برا...

2003
N. R. MOODY D. P. ADAMS D. MEDLIN T. HEADLEY N. YANG A. VOLINSKY

In this study, the effects of diffusion on gold-chromium film durability was determined from interfacial fracture energy measurements on laboratory samples aged to simulate long term service. The samples were prepared by sputter deposition of gold films and chromium adhesive layers on sapphire substrates. Some films were left in the as-deposited condition while others were given an accelerated ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان همدان - دانشکده ادبیات و علوم انسانی 1390

abstract this study is an attempt to determine the effect of nano- technology education on science lesson for fifth grade in primary school in the city of kermanshah. this research is experimental and is conducted in the from of pre-test and post- test for the control group. an achievement test was administered to determine the rate of learning in the students. the research is an applied one. ...

Journal: :The Central African journal of medicine 1986
R T Mossop

Prima facie evidence is presented that, where naturally occuring chromium in water supplies occurs, it is associated with a lower prevalence of diabetes and a lower incidence of mortality from vascular occlusive disease. It is postulated that increased prevalence of such disease in a population is associated with chromium 3 deprivation. This results from con­ sumption of highly refined cereal f...

Journal: :Toxicology and applied pharmacology 2006
Senthivinayagam Subramanian Gopalakrishnan Rajendiran Pasupathi Sekhar Chandrahasan Gowri Pera Govindarajulu Mariajoseph Michael Aruldhas

The present study was designed to test the hypothesis that oxidative stress mediates chromium-induced reproductive toxicity. Monthly semen samples were collected from adult monkeys (Macaca radiata), which were exposed to varying doses (50, 100, 200 and 400 ppm) of chromium (as potassium dichromate) for 6 months through drinking water. Chromium treatment decreased sperm count, sperm forward moti...

2016
Biswajit Singha

One of the most important and toxic heavy metals in wastewater is chromium. Cr (VI) is released from different industrial operations, including metallurgy, leather tanning, paint, textile industries, chemical manufacturing, pulp production, ore and petroleum refining, metal corrosion, electroplating products etc. Hexavalent chromium is toxic, carcinogenic, probably mutagenic and highly soluble....

Journal: :Environmental Health Perspectives 1991
C D Palmer P R Wittbrodt

The remediation of chromium-contaminated sites requires knowledge of the processes that control the migration and transformation of chromium. Advection, dispersion, and diffusion are physical processes affecting the rate at which contaminants can migrate in the subsurface. Heterogeneity is an important factor that affects the contribution of each of these mechanisms to the migration of chromium...

Journal: :Environmental science & technology 2001
Y S Yun D Park J M Park B Volesky

Biosorption has attracted attention as a cost-effective means for the treatment of metal-bearing wastewater. However, the mechanism of metal binding is not clearly understood, and consequently, modeling of the biosorption performance is still raising debates. In this study, the biosorption of trivalent chromium was investigated with protonated brown alga Ecklonia biomass as a model system. Titr...

2014
Nurul Huda Baharuddin Nik Meriam Nik Sulaiman Mohamed Kheireddine Aroua

BACKGROUND In this study the removal of Chromium (III) and Chromium (VI) ions are investigated via polymer enhanced ultrafiltration under important process parameters. This study proposes the use of unmodified starch as a novel polymer in the ultrafiltration process and its performance on the removal of chromium ions was compared with a commonly used polymer, polyethylene glycol. METHODS The ...

2011
Ali A Hemmati

Chromium is an essential micronutrient which is required for normal insulin effect and regulation of blood sugar level. Serum chromium status of patients with type 2 diabetes was compared with control non-diabetic subjects. Blood samples were collected and serum glucose level of both groups was determined. The serum chromium concentration of samples was measured by flame-less atomic absorption ...

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