Mesoporous alumina with narrow pore size distribution centered in the range of 4.4-5.0 nm and with a specific surface area as high as 270 m²·g-1 was prepared via the nanocasting approach using a CMK-3 carbon replica as a hard template. Based on this support, a series of catalysts containing 1, 5, 10, 20 and 30 wt % of chromium was prepared by incipient wetness impregnation, characterized, and s...

Studies of storage and production hydrogen, which is an alternative to fossil fuels, have been intensified. Hydrogen from metal borohydrides via catalyst very attractive because its advantages, such as controlled production, high hydrogen content, nontoxicity, etc. In this study, the catalytic performances nanoporous nickel–chromium alloy nickel–vanadium catalysts prepared with magnetron sputte...

Ammonia boron is one of the chemical compounds with high energy density that eliminates problem storing hydrogen, a clean source. borane (NH3BH3), hydrogen storage compounds; High capacity (19.6% H2 by mass) has very important place in fuel technology due to its stable structure aqueous solution. The main parameter determining ammonia hydrolysis, production efficiency and reaction course cataly...

OBJECTIVES Molecular epidemiological techniques, capable of detecting damage to DNA, were used to see if such damage occurred in the lymphocytes of a group of workers exposed to chromium. The two aims of this pilot study were to see if these new techniques might make useful biological monitoring tools for workers exposed to chromium and also, to help assess whether the current occupational expo...

Arsenic, chromium, and nickel are reported in several epidemiologic studies to be associated with lung cancer. However, the health effects of arsenic, chromium, and nickel exposures are equivocal for children. Therefore, we performed a cross-sectional study to investigate possible associations between the internal concentrations of arsenic, chromium, and nickel and the level of oxidative stress...

OBJECTIVES To compare the self reported health of a group of individuals living in an area contaminated by chromium (chromium group) with a group living in an uncontaminated area (control group), and to assess the effects of perception of risk from exposure to chromium on health. DESIGN Cross sectional study using the SF-36 validated quality of life questionnaire. Further questions were added...

Chromium is a naturally occurring element present in the earth’s crust. Chromium is released to the environment from natural and anthropogenic sources, with the largest release occurring from industrial releases. The industries with the largest contribution to chromium release include metal processing, tannery facilities, chromate production, stainless steel welding, and ferrochrome and chrome ...

BACKGROUND Chromium is an essential element in human nutrition. Serum concentrations of chromium are not well characterized during pregnancy or in gestational diabetes mellitus. OBJECTIVE The objective of this study was to determine whether low plasma chromium concentrations (< or =3 nmol/L) are associated with altered glucose, insulin, or lipid concentrations during pregnancy. DESIGN The s...

Chromium is one of the 25 most widespread elements in the Earth’s crust and occurs as an indelible non-volatile trace element in raw materials used in cement clinker production (clay, limestone and iron additives in particular). Chromium in raw materials mentioned above is mainly in form of trivalent chromium. Naturally occurring chromium (III) is not initially harmful, since it is chemically s...

Reduction of chromium(VI) to chromium(Ill) by thiourea between pH 3.0 and 5.5 is a key aspect of the chrominm(VI)/thiourea/polyacrylamide gel polymer system used in enhanced oil recovery processes. A method has been developed to determine chromium(Vl) concentration during the reduction of chromium(VI) to chromium(III) in this pH range. The reduction reaction is run in the presence of an acetic ...