[en] New particle formation in the atmosphere is an important parameter in governing the radiative forcing of atmospheric aerosols. However, detailed nucleation mechanisms remain ambiguous, as laboratory data have so far not been successful in explaining atmospheric nucleation. We investigated the formation of new particles in a smog chamber simulating the photochemical formation of H2SO4 and organic condensable species. Nucleation occurs at H2SO4 concentrations similar to those found in the ambient atmosphere during nucleation events. The measured particle formation rates are proportional to the product of the concentrations of H2SO4 and an organic molecule. This suggests that only one H2SO4 molecule and one organic molecule are involved in the rate-limiting step of the observed nucleation process. Parameterizing this process in a global aerosol model results in substantially better agreement with ambient observations compared to control runs.

[en] A methodology for collecting data of uranium and molibdenum extraction by lixiviation with sulfuric acid is showed. Discontinuous tests of lixiviation, time influence, temperature, granulation, acid/ore relation, oxidant/ore relation and solid percentage are studied. (C.G.C.)

No abstract available

[en] The behaviour of the voltametric wave of the uranyl ion in sulfuric acid medium was studied using hanging mercury drop electrode voltammetry technique. The scope of the present work was to found the best wave resolution for the uranyl ion in order to apply it to analyse the solutions originated from the purification plants of uranium and other compounds concerning the fuel cycle. (author)

No abstract available

[en] Aldehydes and ketones were converted to their corresponding acetals in the presence of silica-bound sulfuric acid in n-hexane under mild and heterogeneous conditions with excellent yields

[en] The performance characteristics of the Sulfur Cycle Hydrogen Production Process, as identified in the process evaluations, indicate that the system is capable of effectively filling a need for efficient hydrogen production. The experimental and analytical work being performed on the Sulfur Cycle continues to support the technical and economic potential of the system as an efficient and cost effective way to produce hydrogen. The development program, as currently formulated, is predicated on developing and demonstrating the technology on a timely basis to meet the needs of a phased commercialization plan. A scenario is foreseen where sulfurous acid electrolyzers, a key component of the Sulfur Cycle, are used in new generation combined sulfuric acid/hydrogen plants in the late 1980's, the full Sulfur Cycle is deployed in Solar Chemical plants in the 1990's, and the era of large scale merchant hydrogen production, with very high temperature nuclear reactors providing the energy needs of the Sulfur Cycle, starting after the turn of the century. (orig./DG)

[en] PEDOT:PSS-modified GC (PEDOT:PSS/GC) electrode shows enhanced electrocatalytic activity for Pu(IV)/Pu(III) redox couple in sulphuric acid solution compared to GC, Au and Pt electrodes. (author)

[en] The behaviour of a tungsten electrode to cyclic voltametry as a perturbation technique was studied. Tests were carried out in 1M H₂SO₄ (25.0 + - 0.2)⁰C and using a three electrode conventional cell. The electrode potential was measured in relation to a saturated calomel electrode connected to a Luggin capillary. The working electrode consisted of a tungsten wire, of spectroscopic purity, having 0.6 cm² geometric area and a platinum counter-electrode. Considerations about the conditions and feasibility of using such an electrode for electrochemical and electrocatalytic studied are made. (C.L.B.)

[en] The fossil fuel depletion and the environmental pollution caused by use of fossil fuel. It can be solved by new energy source. Recently, hydrogen energy was highly regarded as alternative next generation energy source, because it is so clean that it does not emit carbon dioxide. The sulfur-iodine (SI) process is one of the methods to produce the hydrogen. It is based on simple chemical reactions which are as follows; I₂ + SO₂ +2H₂O = 2HI + H₂SO₄ (1) 2HI = H₂ + I₂ (2) H₂SO₄ = H₂O + SO₂ +1/2O₂ (3) The reaction (1) has been known as the Bunsen reaction, where gaseous sulfur dioxide reacts with iodine and water producing an aqueous solution of iodic acid and sulfuric acid. Those reaction environments are very corrosive. In the study, the corrosion tests of various materials were conducted in boiling sulfuric acid to select appropriate materials