Determination of the deformation characteristics of thawing permafrost soils in the construction of the urengoiskii grés complex

Conclusions 1. The test thawing of soils in the test area in the Urengoiskii GRéS construction sites made it possible to determine the deformation characteristics of permafrost in their natural occurrence and to estimate the rate of consolidation and distributive properties of preliminarily thawed soils. 2. The calculation for the settlements of thawing soils with the use of results of compression tests and visual determination of the ice content led, in the given case, to values with are twice as much as the actual values. 3. Permanently frozen sandy soils in the construction areas are practically noncompressible with thawing, whereas clayey soils are highly compressible with thawing and cannot be made use of as per principle II without preliminary thawing. Deceased. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 16–18, January–February, 1989.     

Investigations of BOR-60 Structural Materials and Prospects for Further Work

Since its startup in December in 1969, the BOR-60 reactor has been used effectively for irradiation of structural and fuel materials in a wide range of dose–temperature parameters. Analysis of the actual computational-experimental parameters (irradiation temperature, damage rates) shows that the irradiation conditions are highly reproducible and can be maintained accurately.The investigations made it possible to study phenomena which are important for building reactors using domestic structural materials and to choose the optimal composition and heat treatment of the materials.New directions are indicated for scientific-research work, for improving and increasing the service life of VVÉR type reactors, and for developing new-generation structural materials for fusion reactors being designed.     

Adsorption of NO synthase inhibitor on dehydroxylated silica

A series of thiazine derivatives with the NO inhibiting effect was synthesized. These derivatives can be used in the treatment of gastrointestinal diseases, as well as antihypotensive (antishock) drugs. The potentially prolonged effect of these substances was studied by the adsorption of 2-N-benzoyl-2-amino-5,6-dihydro-4H-1,3-thiazine hydrobromide (I) on silica (nonporous Polysorb MP with specific surface area S = 330 m²/g and narrow-porous KSS-3 silica gel with S = 600 m²/g). The dehydroxylation of a silica surface significantly increased the adsorption of I. The adsorption kinetic curves of I showed a peak due to the rehydroxylation and deactivation of the silica surface in aqueous solutions. The adsorption rate in physiological solution of I was shown to decrease at a lower concentration of I on the surface of dehydroxylated silica and larger silica particles.     

Technological aspects of assembling‐welding fuel tanks of 1460 and 1570 aluminium alloys

Results are presented on the investigation of the optimization of the temperature–time conditions of high-temperature brazing of structural steels of the austenitic (12Cr18Ni10Ti) and martensitic [06Kh15N6MVFB-Sh (VNS16) and 03Kh12NYuMTR-VD (VNS25)] grades used widely in the manufacture of heat exchangers.     

Preparation of Np, Pu, and U dioxides in nitric acid solutions in the presence of hydrazine hydrate

Heating of nitric acid solutions of Np and Pu (～90°C) in the presence of hydrazine hydrate (HH) leads to the formation of their hydrated dioxides in solution, transforming into crystalline dioxides at 300°C. Thermolysis of a mixed solution of U, Np, and Pu nitrates under the same conditions initially yields hydrated (U,Np,Pu)O₂·nH₂O, which on heating in air to ～300°C transforms into a crystalline solid solution of (U,Np,Pu)O₂. This method for stabilization of U dioxide in the presence of Pu in an oxidizing atmosphere can be used for preparing (U,Pu)O₂ solid solutions of variable composition. This procedure shows doubtless prospects as a simple, efficient, and relatively low-temperature method for the production of MOX fuel for fast reactors.     

Complexation of actinides(VI) with furan-2-carboxylic and thiophene-2-carboxylic acids in aqueous solutions and synthesis of crystalline compounds

Crystalline uranyl compounds with furan-2-carboxylic (F2C) and thiophene-2-carboxylic (T2C) acids containing the complex anions [UO₂(OOCC₄H₃O)₃]^? and [UO₂(OOCC₄H₃S)₃]^? were synthesized and studied by single crystal X-ray diffraction. A previously unknown compound of a transuranium element, Pu(VI), with T2C, also containing the complex anions [PuO₂(OOCC₄H₃S)₃]^?, was synthesized. With Pu(VI) taken as example, the complexation of hexavalent actinides with F2C and T2C in aqueous solutions was studied, and the stability of the complexes PuO₂L⁺ (L is F2C or T2C anion) was determined. The Pu(VI) complexes with F2C are slightly more stable than those with T2C but less stable than Pu(VI) monoacetate complexes. The spectral characteristics of the complexes are discussed.     

Effect of O2, H2O2, and HNO2 on the stability of Np(III–VII) in aqueous solutions

Published data on reactions of Np ions with O₂, H₂O₂, HNO₂, and HNO₃ in solutions of various compositions in a wide pH range are considered. O₂ oxidizes Np(III) in acid solution and Np(IV) and Np(V) in alkaline solutions. H₂O₂ exhibits dual behavior. In weakly acidic solutions, it converts Np(III) and (IV) to Np(V), in 0.75?C1 M NaHCO₃ it oxidizes Np(V) to Np(VI), whereas in dilute HClO₄ and HNO₃ and in carbonate and alkali solutions it reduces Np(VI), and in alkali solutions it reduces Np(VII). The first step of reduction in most cases is the formation of the Np(VI) peroxide complex, and the next step is the intramolecular charge transfer. In concentrated HNO₃ solutions, H₂O₂ converts Np(V) to Np(IV) and Np(VI) and then reduces Np(VI). Some radiation-, photo-, and sonochemical reactions occur via formation of excimers, i.e., of dimers arising from excited and unexcited Np ions. The excimer decomposes into two ions with higher and lower oxidation states. In reduction reactions, the excimer eliminates H₂O₂ (in addition to the H₂O₂ arising as primary product of water radiolysis). In HNO₃ solutions, oxidation of Np ions occurs only in the presence of HNO₂ arising as reaction product or upon radiolysis, photolysis, or sonolysis. The active species are NO ₂ ^? , NO₂, and NO⁺ present in equilibrium with HNO₂.