Photocleavage of Water in Organized Molecular Systems

Photocleavage of water by solar light in molecular systems is discussed. The advantages of organized molecular photosystems are demonstrated for the main steps of the photocleavage process: charge photoseparation, stabilization of the separated charges, and catalytic production of hydrogen and oxygen under the action of one-electron reductants and oxidants, respectively.     

Friction coefficient in gelatin and polyacrylamide gels

Summary The slow neutron transmission technique is used to measure the friction coefficient f of gel macromolecules moving against a solvent. It is shown that in the range of concentrations C=3–30%, f of gelatin gels is linearly dependent on C. The values of the monomer friction coefficient of gelatin and the friction coefficient at infinite dilution are determined. It is demonstrated that the friction coefficient of polyacrylamide gels varies as the viscosity of a solvent in a wide temperature range, however at temperatures below 25°C the deviation from proportionality is observed.     

Reduction of Np(VI) with Carbohydrazide in a Perchloric Acid Solution

Radiochemistry - The stoichiometry of the reaction of Np(VI) with carbohydrazide (NH2NH)2CO in a 0.02 M HClO4 solution was studied by spectrophotometry. With Np(VI) taken in excess, 1 mol of...     

Development of vibration damping materials based on butyl rubber: A study of the phase equilibrium,rheological, and dynamic properties of compositions

A detailed study of butyl rubber-based vibration damping formulations linking their composition, morphology, phase structure, viscosity, mechanical loss factor, and other characteristics is presented for the first time. High performance of the compositions including aromatic petroleum oil is explained by limited solubility of the plasticizer that leads to the formation of a highly-viscous emulsion (η_20°C ≈ 1000 Pa·s) consisting of a swollen butyl rubber matrix and dispersed oil droplets in the broad composition range. Chalk is found to be the best inorganic filler as its spherical particles provide strong adhesion to the reinforcing layer of aluminum foil. Aiming to eliminate ecologically unfriendly aromatic compounds, a new low-cost binding agent formulation based on butyl rubber mixed with polyisobutylene and highly refined mineral oil is suggested. Being environmentally safe, it possesses high viscosity of 1000–3000 Pa·s, cohesion strength of 3.5–5.0 N/cm, penetration of 4.5–6.0 mm, and mechanical loss factor up to 0.34 at room temperature, which are as good as, or even better than, the properties of currently produced vibration damping materials containing aromatic compounds. New materials can be used in car and aircraft parts for effective vibration isolation.     

Ultrasonic Multichannel Flaw Detector for Testing Rails with Signal Recording

Although automated testing instruments have been introduced intensely on the railways of Russia, up to 95% of hazardous flaws in rails are detected by ultrasonic two-line (removable) flaw detectors. The paper describes the functional diagram and basic functions of an ultrasonic detector of the new generation, AVIKON-01, with continuous recording of data. The instrument is supplied with the software package for analysis of testing results, and it has advantages of both hand-held removable flaw detectors and high-performance instruments for nondestructive testing of rails.