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[en] The results of Phase II of an investigation directed towards quantifying the explosive hazards of hydrogen sulphide in air are described. This second and final phase is focussed on flame acceleration until detonation in obstacle environments simulating a heavy water plant. The results of previous experimental tests, both small and large scale, are compiled and summarized and the results of a series of flame acceleration tests are reported. These tests were performed in order to assess the potential for damaging explosions in simulated industrial environments with repeated obstacles. The experimented apparatus consisted of a channel 1.8 m x 1.8 m in cross-section and 15.5 m long. Two obstacle configurations were tested, corresponding to 500 mm or 220 mm diameter tubes mounted across the channel at regular intervals. Tests were performed with acetylene, propane and hydrogen sulphide fuels. The results of numerical simulation are also reported and compared with the observed results. Scaling predictions are also made. The key results are summarized in the main text, and detailed reports covering the various aspects are included in three annexes
[en] Hydrogen sulfide (H2S) is a signaling gasotransmitter that plays an important role in modulating the functions of different systems. We have reported a xanthene-based colorimetric and fluorescence Probe A for the selective detection of H2S over other sulfide-containing analytes. The emission intensity increases linearly with NaSH concentrations in the low concentration range suggested that it shows high sensitivity toward H2S with a detection limit as low as 7 nM. This probe exhibits an enhanced up to 250-fold fluorescence enhancement at λem 510 nm in the presence of H2S (50 μΜ). In addition, Probe A can be applied for fluorescent imaging of H2S in living cells, providing a potentially powerful molecular imaging tool for imaging H2S.
[en] In view of producing heavy water, the influence of the deuterium proportion in the basic substances, on the efficiency of the isotope exchange process H2S - H2O for two temperatures was studied. Heavy water is extracted from ordinary water and concentrated from 0.014 per cent to 5-15 per cent D2O by isotope bithermal exchange with the hydrogen sulphite. Theoretical and experimental research was carried out in laboratories and then applied on a pilot plant by designing and testing a drying equipment for hydrogen sulphite. The maximum H2S concentration rose to 99.84 per cent. The purity of the hydrogen sulphite resulting from the pilot plant, as well as the optimization of the installation for producing H2S depending on the deuterium distribution, make sure that the two methods for the preparation of sodium sulphite and hydrogen sulphite can be applied in industry. (author)
[en] The authors studied the decomposition of hydrogen sulfide in a barrier discharge. The choice of a barrier discharge was not made by chance. It possesses the following properties resulting in its having advantage over other types of discharges. (1) Use of a barrier discharge permits one to obtain superequilibrium atom concentrations for a given temperature owing to the nonisothermic plasma of a barrier discharge, i.e., along with the existence of a relatively low molecular gas temperature there is a very high electron gas temperature; this temperature difference is typical of an isobaric potential in the low temperature plasma of a barrier discharge, which lasts till cessation of operation; (2) a large number of microscopic discharges fill the entire discharge zone and as a consequence, the charged particles attain very high energies, assuring their intense destructive action; (3) the mean gas temperature in the barrier discharge hardly exceeds the temperature of the surroundings so there is no significant heat loss. 6 refs., 1 fig
[en] The diffusivities of HS- and H2 have been determined from profile analysis and steady state transport experiments. The diffusivity of HS- was found to be 9x10-12 and 4x10xsec1 in MX-80 and Erbsloeh bentonite respectively. The results are in fair agreement with the results earlier obtained for Cl- and I-. The H2 diffusivity calculated from steady state transport was found to be surprisingly low (3.6x10-12m2xsec-1). Various heavy anions with molecular weights 290-30x103 were found to migrate through MX-80 bentonite with diffusivities in the range (2,1-0,75)x10-15m2xsec-1. (Author)
[en] A total of 25 targeted hydrogen sulfide donor–pentacyclic triterpene hybrids were designed, synthesized and evaluated on the basis of inspiring reports about hydrogen sulfide donor molecules and oleanolic acid derivatives on anti-tumor activity. The results revealed that only some hybrids (10a, 10b, 12a, 12b, 13a, and 15b) showed moderate anti-proliferation activity against K562 cell line. It indicated that oleanane-type, (R)-lipoic acid and TBZ groups were much more favorable to the anti-proliferation activity. Furthermore, C-3 OH was more beneficial than C-28/29 COOH in the oleanane-type to the antitumor activity of the batch of (R)-lipoic acid derivatives. And among them, only compound 13a exhibited moderate anti-proliferation activity against both K562 and K562/ADR cell lines, while it exhibited no anti-proliferation activity against BEL-7402 and L-O2 cell lines. Therefore, it suggested that it was not suitable for hybridization of hydrogen sulfide donors attached to oleanolic acid, ursolic acid and glycyrrhetinic acid in the field of anti-tumor.
[en] There is provided a process for treatment of the liquid water feed and effluent of a gas and liquid contact system in which flows of hydrogen sulfide gas saturated with water vapor and liquid water saturated with hydrogen sulfide are contacted at elevated temperature and pressure. The process comprises recovering heat and hydrogen sulfide from the effluent for return to the gas and liquid contact system by passing the effluent through at least one zone maintained at a pressure lower than the system pressure but higher than atmospheric pressure in order to release hydrogen sulfide gas containing water vapor. The released gas is cooled by direct contact with a flow of water, thereby raising the temperature of the water, which is then passed to the gas and liquid contact system. The cooled released gas is compressed for return to the gas and liquid contact system. (LL)
[en] Selective oxidation of hydrogen sulfide, a highly toxic industrial gas which is produced by petroleum refineries and natural gas processing plants in increasing amounts, was studied over iron-molybdenum oxides with various Fe-Mo ratios. An unexpected synergistic phenomenon in catalytic activity was observed for the Fe-Mo binary oxides, suggesting that a new compound (Fe2(MO4)3) is formed in the binary oxide which is more active than the single oxide catalysts Fe2O3 and MoO3. The reaction order obtained suggests that catalyst activity is governed mainly by the adsorption and activation of the reactant hydrogen sulfide, which is an acidic compound with an electronegative sulfur atom and two electropositive hydrogen atoms. 17 refs., 1 tab., 4 figs
[en] This work presents briefly the current status of the electrochemical kinetics, with a particular stress on corrosion in a H2O-H2S environment. Experimental methods are described. On the basis of the obtained results a comparison is given concerning the performances and the limitations of the different working modalities. Depending on the specific method adopted ways of optimization are indicated