On the possibility of using of materials based on adhesive prepregs in Arctic conditions

Analysis of the properties of adhesive prepregs, which were synthesized based on glass fabrics and carbon fillers, and materials made on their basis was performed. It was shown that the composite materials based on prepregs with VSK-14-2m binder surpass composite materials based on prepregs synthesized by the impregnation of fabrics with soluble binders in terms of physical and mechanical properties at–130°C, water resistance, hygroscopicity, and water absorption.     

On the possibility of using organic phosphors in thermoluminescence dosimetry

Organic materials in general and polymers in particular have traditionally been considered as to be phosphors and have been ruled out as materials which could be useful in dosimetry of ionizing radiations by thermoluminescence. Some results reported during the past decade suggested possibilities of organic phosphors with good thermoluminescence characteristics. Experiments were undertaken to exploit the various possibilities. The results show that “crystalline polymers” can have adequate thermoluminescence properties to be useful in dosimetry. It is suggested that further studies on thermoluminesence in crystalline polymers and highly drawn fibers of high polymers will prove fruitful.     

The applicability of adhesives in Arctic conditions

Analysis of properties of cold-setting epoxy adhesives and various types of film adhesives is carried out with reference to their applicability in Arctic conditions. Data on waterproofness, water absorption, and hygroscopic properties of the set adhesive films are determined. The application of adhesive joints at–60°C is considered.     

On the possibility of isolating diazirine N-oxides

Ab initio molecular orbital calculations at the 6-31G level predict that diazirine N-oxide is more stable with respect to its constituent fragments, singlet CH₂ and N₂O₂, than diazirine is with respect to singlet CH₂ and N₂. In view of these results and the many diazirines which have been reported, it is suggested that it may be possible to detect a suitably substituted diazirine N-oxide.     

On the possibility of using an electromagnetic radioisotope separator in conjunction with charged-particle and photon-activation analysis

A proposal is made for the use of electromagnetic radioisotope separation following charged particle, photon- or neutron-activation. Features of this separation technique are speed and selectivity, opening new possibilities for simultaneous determination of several trace elements, especially the light ones. Preliminary experiments have shown the possibilities if this separation technique is used in conjunction with activation analysis.     

On the possibility of studying the electronic factor in catalysts using the method of space charge limited currents

A possibility is proposed for studying changes in the electronic characteristics of surface defects in adsorption and catalysis, using conductivity measurements in the region of injection currents. The change in the spectrum of electron traps is interpreted by a coordinative mechanism of adsorption.

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On the possibility of dielectric saturation in molecular systems

Using the model of dielectric continuum and Lorentz's field, we have demonstrated that the polarization of the first coordinated shell of the solvent molecules around a charged solute molecule is weakly saturated. The dielectric saturation effect has also been observed in the calculated result that the ratio between the equilibrium and non-equilibrium free energies considerably deviates from unity which is expected in the absence of dielectric saturation.     

On the possibility of luminescence of U ion

Uranium(IV) solutions are violet in colour under certain conditions. Direct experiments excluded the possibility that its origin is luminescence of U ions. The unusual colour behaviour of mentioned systems follows most likely from peculiarities of colour perception of the human eye, in combination with specific properties of the U ion absorption spectrum.     

On the possibility of using model potentials for collision integral calculations of interest for planetary atmospheres

The interaction energy in systems (atom–atom, atom–ion and atom–molecule) involving open-shell species, predicted by a phenomenological method, is used for collision integral calculations. The results are compared with those obtained by different authors by using the complete set of quantum mechanical interaction potentials arizing from the electronic configurations of separate partners. A satisfactory agreement is achieved, implying that the effect of deep potential wells, present in some of the chemical potentials, is cancelled by the effect of strong repulsive potentials.     

Criticisms of standard ozone resistance testing of wax protected rubbers under static conditions

Evidence is presented to support the criticism of current standard test methods for static ozone exposure that the test temperature and conditioning procedure normally used can produced misleading results. It is suggested that, for rubber which rely on migration of wax to the surface for protection, more realistic results are obtained if conditioning and testing are carried out at 0°C.     

The possibility of using radiation-reclaimed butyl rubber in the building industry

Studies are performed to demonstrate the possibility of the valuable replacement of butyl rubber by a radiation-induced degradation product for the production of different waterproofing and roofing materials in the building industry. The efficiency of using nitroso compounds, such as p-dinitrobenzene and quinol ether, as vulcanizing agents is investigated. It is shown that a reclaimed product obtained at an irradiation dose of 20 Mrad may be used as an efficient adhesive additive. The addition of such a reclaimed product to a solution-born mastic in an amount of 30 mass parts per 100 mass parts of rubber substantially enhances the adhesion to concrete, steel, polyethylene, etc. other properties remaining unchanged.     

On the possibility of a pH-metric determination of ozone

A novel approach for the detection and determination of ozone is presented. The method is based on monitoring the pH increase due to the reaction of ozone with an unbuffered solution of KI, during which hydroxyl ions are produced. Based on theoretical calculations, a pH increase of 0.01 pH-units corresponds to 2.3 × 10^?9 M of reacting concentration of ozone, when the initial pH of the KI solution is 7.00. Deviations from the ideal neutrality due to the presence of traces of acidic or basic impurities can be taken into account. A comparison between the expected pH changes and those experimentally achieved for given amounts of ozone has been made.     

On rheology,cure kinetics and chemorheology of gum rubbers

The paper presents an experimentally supported modeling approach, which describes the rheology, detailed cure kinetics, and chemorheology of a gum elastomer in course of sulfur accelerated vulcanization. Changes in the rheology during cure reaction are correlated with degree of cross-linking, described by vulcanization kinetics. Oil extended SBR exemplifies the approach.     

On the possibility of an STM-induced dissociative electron transfer

The process of dissociative adsorption of a molecule on an electrode in a system of the type in situ scanning tunneling microscopy (STM) is investigated theoretically. It is shown that, in the case of fully nonadiabatic or partly adiabatic electron transfer, the presence of the tip of STM may either accelerate (or even induce) or decelerate the process of dissociation of the molecule, depending on the sign of the bias voltage. The maximum effect takes place in the case of strong interaction of the molecule with both electrodes (fully adiabatic electron transfer). In this limit, diagrams of kinetic modes, which mark off the boundaries between processes of different types possible in a given system, are constructed.Translated from Elektrokhimiya, Vol. 41, No. 3, 2005, pp. 273–284.Original Russian Text Copyright © 2005 by Kuznetsov, Medvedev.     

On the possibility of the existence of molecular nitrogen allotropes

The possibility of the existence of nitrogen molecules with an even number of atoms of composition N₄, N₆, N₈, and N₁₀ has been discussed with the use of the QCISD and G3 quantum-chemical methods. From these data, a conclusion has been made that three new nitrogen allotropes with an even number of atoms in a molecule can exist, namely, N₄ shaped as a rectangle and regular tetrahedron and N₆ with a shape remotely resembling an “open book.” The bond lengths and bond and torsion angles in each of these molecules have been reported.     

On the possibility of structural and magnetic ordering in magnetic colloids

The aggregation stability of a magnetic colloid at an excess content of a surfactant is studied. The presence of aggregates with a nonzero magnetic moments is revealed; on this basis, magnetic ordering of magnetic particles in them is regarded as possible. The possible mechanisms of the formation of periodic structural lattices appearing under the action of a direct electric field on the magnetic colloid are studied. A fundamental difference between the structurization processes induced by a surfactant and by an electric field is noted: structurization processes occurring at the excess of surfactant may be associated with the flocculation, whereas such processes proceeding under the effect of an electric field may be due to phase separation of the colloid.__________Translated from Kolloidnyi Zhurnal, Vol. 67, No. 2, 2005, pp. 161–166.Original Russian Text Copyright © 2005 by Dikanskii, Vegera, Zakinyan, Nechaeva, Gladkikh.     

On the possibility of plasma chemical conversion of hydrogen chloride

The possibility of plasma chemical conversion of hydrogen chloride was explored. It was shown that, for the typical conditions of atmospheric pressure discharges, the use of pure HCl as the plasma-forming gas does not provide the conversion degrees higher than 4%. It was found that high (>95%) HCl conversion degrees, as well as maximum yields of Cl₂ may be obtained in HCl-O₂ mixtures due to the plasma-assisted oxidative decomposition of the reactant. The optimal process conditions in terms of the electron density and feed gas composition were determined.     

On the possibility of quantum beats in the total fluorescence of large molecules

The temporal evolution of the total emission from excited electronic states of a large molecule which corresponds to the statistical limit for radiationless relaxation is considered within the two-discrete-states model. It is shown that quantum beats in total (spectrally unresolved) emission may be revealed when the excited discrete levels differ in their rate constants for radiationless relaxation even if they have equal rate constants for radiative decay.