in this article, a complete model for the mixed flow slurry reactor for polymerization of ethylene to high density polyethylene in the presence of ziegler-natta catalyst is presented. in addition to the effects of the multiple active sites, the effect of other important parameters such as the catalyst concentration, co-catalyst, hydrogen, monomer, impurities and pressure on the mass-average and...

(Received: January 26, 2012; Accepted: March 25, 2012) Abstract: Removal of hydrogen sulfide from mixed gas was successfully carried out in a batch reactor. The isolated microorganism from Ramsar hot spring was cultured and adapted in an environment with hydrogen sulfide. At 35°C, maximum cell dry weight was 0.43 g/l. For the hydrogen sulfide removal, effect of temperature in the range of 25 to...

A method for the analysis of dissolved hydrogen sulfide in crude oil samples is demonstrated using gas chromatography. In order to effectively eliminate interferences, a two dimensional column configuration is used, with a Deans switch employed to transfer hydrogen sulfide from the first to the second column (heart-cutting). Liquid crude samples are first separated on a dimethylpolysiloxane col...

The physical adsorption of hydrogen sulfide and carbon dioxide gases on the zigzag (5,0) carbon nanotubes doped with nitrogen was investigated through the application of B3LYP/6-31G* at the level of theory on Gaussian 03 software. A variety of stable and high abundance structures of nitrogen doped carbon nanotubes were considered in order to study the interaction between the mentioned gases in ...

Hydrogen sulfide (H(2)S) is enzymatically generated in mammalian tissues from either L-cysteine or L-homocysteine. H(2)S possesses multiple biological activities, including regulation of vascular tone and blood pressure. Hydrogen sulfide produced in endothelial cells, vascular smooth muscle cells, and perivascular adipose tissue dilates blood vessels by activating ATP-sensitive potassium channe...

Polymer membranes are attractive for molecular-scale separations such as hydrogen purification because of inherently low energy requirements. However, membrane materials with outstanding hydrogen separation performance in feed streams containing high-pressure carbon dioxide and impurities such as hydrogen sulfide and water are not available. We report highly permeable, reverse-selective membran...

Hydrogen sulfide (H2S) is an important biological messenger, but few biologically-compatible methods are available for its detection in aqueous solution. Herein, we report a highly water-soluble naphthalimide-based fluorescent probe (L1), which is a highly versatile building unit that absorbs and emits at long wavelengths and is selective for hydrogen sulfide over cysteine, glutathione, and oth...

background and objective: cerebral arteriovenous malformation (cavm) hemodynamic is disease condition, results changes in the flow and pressure level in cerebral blood vessels. measuring flow and pressure without catheter intervention along the vessel is big challenge due to vessel bifurcations/complex bifurcations in arteriovenous malformation patients. the vessel geometry in cavm patients are...

Thiosulfate formation and biodegradation processes link aerobic and anaerobic metabolism of cysteine. In these reactions, sulfite formed from thiosulfate is oxidized to sulfate while hydrogen sulfide is transformed into thiosulfate. These processes occurring mostly in mitochondria are described as a canonical hydrogen sulfide oxidation pathway. In this review, we discuss the current state of kn...

and Implications Ruminal hydrogen sulfide concentrations may be a useful tool to determine risk of cattle developing sulfurinduced polioencephalomalacia. In this study, steers were fed a low sulfur (0.2% S) or a high sulfur diet (0.7% S) and ruminal hydrogen sulfide concentrations were measured. Although differences in ruminal hydrogen sulfide due to sulfur intake were maintained throughout the...