The main insulation system in high-voltage direct current (HVDC) transformer consists of oil-paper insulation. The formation of space charge in insulation paper is crucial for the dielectric strength. Unfortunately, space charge behavior changes because of the corrosive sulfur substance in oil. This paper presents the space charge behavior in insulation paper induced by copper sulfide generated...

in this study, effects of solid concentration, temperature, and initial fe2+ concentration on bioleaching of sulfide mineral (chalcopyrite) obtained from sarcheshmeh copper mine in the region of kerman located in the south of iran were investigated. a mesophilic iron oxidizing bacterium, acidithiobacillus ferrooxidans has been isolated from a typical chalcopyrite copper concentrate of the menti...

Two strains of Rhodotorula and one of Trichosporon precipitated dissolved copper with H(2)S formed by reducing elemental sulfur with glucose. Iron stimulated this activity under certain conditions. In the case of Rhodotorula strain L, iron stimulated copper precipitation aerobically at a copper concentration of 18 but not 180 mug/ml. Anaerobically, the L strain required iron for precipitation o...

Lysine-2,3-aminomutase from Clostridium SB4 contains iron and sulfide in equimolar amounts, as well as cobalt, zinc, and copper. The iron and sulfide apparently constitute an Fe-S cluster that is required as a cofactor of the enzyme. Although no B12 derivative can be detected, enzyme-bound cobalt is a cofactor; however, the zinc and copper bound to the enzyme do not appear to play a role in its...

Palladium-copper alloys continue to be of interest for hydrogen membrane applications because of their high catalytic activity for hydrogen dissociation, high hydrogen permeability, robustness, and degradation resistance in the presence of sulfur-containing compounds. This sulfur tolerance makes these alloys attractive for membrane applications where sulfur compounds are likely to be present, s...

Monte Carlo simulations using crystal chemical constraints have been used to elucidate the copper diffusion mechanisms in copper-doped zinc sulfide. Relaxation around the ZnSuCu S interface allows facile copper diffusion, particularly in the 22x presence of substitutional oxygen or sulfur vacancies. Copper diffusion is responsible for the brightness degradation in this electroluminescent materi...

Acid-volatile sulfides (AVS) are an important metal-binding phase in sediments. For sediments that contain an excess of AVS over simultaneously extracted metal (SEM) concentrations, acute or chronic effects should not result from the metals Cd, Cu, Ni, Pb and Zn. While AVS phases may exist in surface sediments, the exposure to dissolved oxygen may oxidize the AVS and release metals to more bioa...

Chalcocite (Cu2S) has been deposited via pulsed chemical vapor deposition (PCVD) into a porous TiO2 matrix using hydrogen sulfide and a metal-organic precursor. The precursor used is similar to the more common Cu(hfac)(tmvs) precursor, but it is fluorine free and exhibits increased thermal stability. The simultaneous exposure of the substrate to the copper precursor and hydrogen sulfide resulte...

The removal of copper dissolved in liquid stags by pyrometalIurgical means such as gaseous reduction and sulfidization is thermodynamically investigated. The lowest level possible for copper content is theoretically determined and compared. The results show that gaseous reduction is not as effective as sulfidization. Slags with very low levels of dissolved copper can be obtained with sulfide tr...