نتایج جستجو برای: شاخص cr

تعداد نتایج: 119928  

Journal: :Journal of agricultural and food chemistry 2007
Estela Figueiredo M Elisa Soares Paula Baptista Marisa Castro M Lourdes Bastos

An ETAAS method was validated to quantify total Cr and Cr(VI) in mushrooms and the underlying soils. The method includes a sample pretreatment for total Cr dissolution using a wet acid digestion procedure and a selective alkaline extraction for Cr(VI). The limits of detection were, expressed in microg/L, 0.15 and 0.17 for total Cr and Cr(VI), respectively. The linearity ranges under the optimiz...

ژورنال: مهندسی معدن 2011

سد باطله معدن مس سرچشمه حاوی فلزات سنگین زیادی است. به این منظور،  رسوبات مجتمع مس سرچشمه، برای تعیین غلظت فلزات سنگین و شدت آلودگی، آنالیز شیمیایی شدند. در واقع، هدف این پژوهش، ارزیابی میزان آلودگی فلزات سنگین (Co، Cu، Mo، Zn، Cr، Mn، Ni، Pb، Ti و Fe) در رسوبات معدن مس سرچشمه منتهی به سد باطله است. در این پژوهش، شاخص‌های آلودگی نظیر ضریب آلودگی، شاخص بار آلودگی، فاکتور غنی‌شدگی و شاخص زمین‌انب...

ژورنال: :بلورشناسی و کانی شناسی ایران 0
بیژن اعتمادی department of earth sciences, faculty of sciences, shirazuniversity, shiraz, iranبخش علوم زمین، دانشکده علوم، دانشگاه شیراز زهرا ذاکرعباسی department of earth sciences, faculty of sciences, shirazuniversity, shiraz, iranبخش علوم زمین، دانشکده علوم، دانشگاه شیراز

سازندهای رازک و میشان (میوسن پیشین تا میوسن میانی) در مناطق پل کوار و زنجیران در جنوب و جنوب غرب فارس و در کمربند چین خورده ی زاگرس بررسی شدند. کانی­های اصلی عبارتند از ایلیت- موسکویت، کلریت، کلسیت، کوارتز و کانی­های فرعی آلبیت و پالی گورسکیت. از نظر ژئوشیمی مقادیر mgo و cao بالاتر و مقادیر  sio2، al2o3، fe2o3، na2o وk2o کمتر از نمونه­های استاندارد nasc، paas وuc را نشان می­دهد. الگوی ree بهنجا...

Journal: :Occupational and environmental medicine 1994
J Nethercott D Paustenbach R Adams J Fowler J Marks C Morton J Taylor S Horowitz B Finley

Over the past 60 years, dose-response patch test studies by various methods have been conducted in an attempt to identify the minimum elicitation threshold (MET) concentration of hexavalent chromium (Cr(VI)) that produces an allergic response in Cr(VI) sensitive subjects. These data are not adequate, however, to provide an accurate estimate of the MET because of the variability in the patch tes...

Journal: :iranian journal of applied animal science 2015
l.d. abd-elsamee i. el-wardany n.g. ali o.m. abo-el-azab

to evaluatethe effects of supplementing diets of growing japanese quails (n=450; 7 days old) with chromium (cr) yeast and / or mannan oligosaccharides (mos) on productive performance, carcass traits and the immune system are reported. diets were a basal diet (control) or the basal diet supplemented with 600 mg cr-yeast/kg (cr 1), 1200 mg cr-yeast/kg (cr 2), 1.0 g mos/kg, cr 1 + mos or cr 2 + mo...

Six soil amendments including municipal solid waste compost (MSWC), coal fly ash (CFA), rice husk biochar prepared at 300°C (B300) and 600°C (B600), zerovalent iron (Fe0), and zerovalent manganese (Mn0) were evaluated to determine their ability to reduce mobility of chromium (Cr) in a Cr-spiked soil. The Cr-spiked soil samples were separately incubated with selected amendments at 2 and 5% [weig...

In this study, the concentrations of Zn and Cr in downstream waters from Uzunçayır Dam (Tunceli, Turkey) were monitored during spring (March, April, May) and summer (June, July, August) season. Zinc and Cr concentrations in surface water samples were detected using the ICP-MS device. According to the data obtained the lowest Zn and Cr concentrations in the spring season were 65.43±3.2 μg/L in M...

Journal: Pollution 2019

In this study, the concentrations of Zn and Cr in downstream waters from Uzunçayır Dam (Tunceli, Turkey) were monitored during spring (March, April, May) and summer (June, July, August) season. Zinc and Cr concentrations in surface water samples were detected using the ICP-MS device. According to the data obtained the lowest Zn and Cr concentrations in the spring season were 65.43±3.2 μg/L in M...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2007
Christopher Oze Dennis K Bird Scott Fendorf

Naturally occurring Cr(VI) has recently been reported in ground and surface waters. Rock strata rich in Cr(III)-bearing minerals, in particular chromite, are universally found in these areas that occur near convergent plate margins. Here we report experiments demonstrating accelerated dissolution of chromite and subsequent oxidation of Cr(III) to aqueous Cr(VI) in the presence of birnessite, a ...

Journal: :JCM 2012
Youping Zhao Lizdabel Morales-Tirado

This article first briefly reviews the basic concepts about cognitive radio (CR) technology and CRenabled cognitive wireless communications, and then discusses the differentiating features of CR and the fundamental theories or principles behind CR, especially from the artificial intelligence and machine learning perspective. As a CR testbed plays an important role in the transition of CR techno...

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