نتایج جستجو برای: gypsum percentage

تعداد نتایج: 137937  

2017
Adi Torfstein Alexandra V. Turchyn

We report the δ34S and δO(SO4) measured in gypsum, pyrite, and elemental sulfur through a 456-m thick sediment core from the center of the Dead Sea, representing the last ∼200 kyrs, as well as from the exposed glacial outcrops of the Masada M1 section located on the margins of the modern Dead Sea. The results are used to explore and quantify the evolution of sulfur microbial metabolism in the D...

Journal: :Environmental Health Perspectives 1974
F. Pott F. Huth K. H. Friedrichs

Fibrous dusts (chrysotile, glass fibers, nemalite, palygorscite, and gypsum) and granular dusts (actinolite, biotite, hematite, pectolite, sanidine, and talcum) were injected intraperitoneally into rats. The fibrous dusts (other than gypsum) resulted in a high incidence of mesothelioma (30 - 67%). Gypsum produced only 5% and granular dusts none at all. It is suggested that the fibrous shape lea...

Journal: :مرتع و آبخیزداری 0
فاطمه نقی زاده اصل فارغ التحصیل کارشناسی ارشد مدیریت مناطق بیابانی، دانشگاه تهران، ایران محمد جعفری استاد، دانشکده منابع طبیعی دانشگاه تهران، ایران حسین آذرنیومد استاد، دانشکده منابع طبیعی دانشگاه تهران، ایران محمد علی زارع چاهوکی استاد، دانشکده منابع طبیعی دانشگاه تهران، ایران

in this study, the role of soil properties in making difference between plant communitieswas examined. first, four plant types were identified, including pteropyrumaucheri-salsolarigida، astragalus gossypinus - acanthophyllum herateens، amygdalus scoparia – achilla millefolium and ephedra intermedia – erigon capestra, through randomized systematic sampling and field survey in representative are...

2004
V. ILLERA F. GARRIDO C. VIZCAYNO M. T. GARCÍA - GONZÁLEZ

Lime, gypsum and various gypsum-like by-products have long been applied to soil surfaces as ameliorants of soil acidity and aluminium and manganese toxicity. We examined changes in chemical and mineralogical properties at two different depths in two acid soils one year after the application of gypsum, phosphogypsumþ dolomitic residue, red gypsumþ dolomitic residue, sugar foam, and sugar foamþmi...

1999
MARGUERITE E. VOORHEES

Revegetation efforts generally have failed to establish substantial cover on bentonite mine spoil, but certain amendments have shown promise for improving spoil as a plant growth medium. These growthpromoting improvements were at least partially the result of effects of these amendments on spoil chemistry. We undertook this study to determine the effects of selected amendments (gypsum, fertiliz...

2012
Z. Pavlík J. Žumár M. Pavlíková

Water vapour transport properties of gypsum block are studied in dependence on relative humidity using inverse analysis based on genetic algorithm. The computational inverse analysis is performed for the relative humidity profiles measured along the longitudinal axis of a rod sample. Within the performed transient experiment, the studied sample is exposed to two environments with different rela...

2007
Hailiang Dong Jason A. Rech Hongchen Jiang Henry Sun Brenda J. Buck

[1] Soil sulfates are present in arid and hyperarid environments on Earth and have been found to be abundant in soils on Mars. Examination of soil gypsum from the Atacama Desert, Chile, the Mojave Desert, United States, and Al-Jafr Basin, Jordan, revealed endolithic cyanobacteria communities just below the surface of soil gypsum samples. Optical and scanning electron microscope observations of ...

2014
D. Tsamatsoulis

Cement is produced by co-grinding clinker, gypsum and other components defined in the Cement Standards like limestone, pozzolans, fly ash and slag. The grinding is usually performed in horizontal ball mills. Gypsum is typically the basic source of sulphates (SO3) in the cement. The effect of gypsum on the cement quality is critical and twofold. It affects two of the main properties of this prod...

2006
Anditya Rahardianto Wen-Yi Shih Ron-Wai Lee Yoram Cohen

The utility of a laboratory diagnostic approach was investigated for a systematic evaluation of the impact of operating conditions, membrane type, and antiscalant effectiveness on membrane mineral salt scale formation. The study focused on low-pressure reverse osmosis (RO) membrane desalting of brackish water with high potential for scaling by calcium sulfate dihydrate (gypsum). Gypsum scale fo...

Journal: :Journal of environmental quality 2012
Ray B Bryant Anthony R Buda Peter J A Kleinman Clinton D Church Louis S Saporito Gordon J Folmar Salil Bose Arthur L Allen

High levels of accumulated phosphorus (P) in soils of the Delmarva Peninsula are a major source of dissolved P entering drainage ditches that empty into the Chesapeake Bay. The objective of this study was to design, construct, and monitor a within-ditch filter to remove dissolved P, thereby protecting receiving waters against P losses from upstream areas. In April 2007, 110 Mg of flue gas desul...

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