Variants of closing the nuclear fuel cycle

Influence of the nuclear energy structure, the conditions of fuel burnup, and accumulation of new fissile isotopes from the raw isotopes on the main parameters of a closed fuel cycle is considered. The effects of the breeding ratio, the cooling time of the spent fuel in the external fuel cycle, and the separation of the breeding area and the fissile isotope burning area on the parameters of the fuel cycle are analyzed.     

Catalpa oil seeds. II

Summary The results of the investigation of the glyceride composition of three samples of the seeds oils of various species of catalpa from different growth sites have shown a great similarity in the amounts of certain groups of triglycerides that they contain, in spite of the considerable differences in the fatty-acid compositions of these samples. An unusual affinity of unsaturated acids for the central position of the glycerol molecule and also a specificity of eleostearic acid in esterifying the extreme positions of the glycerol molecule in catalpa seed oils have been found.Kalinin Polytechnic Institute. Moscow Branch of the All-Union Scientific-Research Institute of Fats. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 487–491, July–August, 1977.     

Catalytic and physico-chemical properties of La1?xSrxCoO3 perovskites

Catalytic properties of strontium-substituted lanthanum cobaltites La_1–xSr_xCoO₃ in the reaction of CO oxidation were compared with the data about chemical composition of the surface and bulk defect structure. It was found that (1) the initial catalytic activity correlates with the cobalt concentration on the surface; (2) surface composition differs from the bulk one; (3) the steady-state activity is proportional to the density of bulk extended defects. Under our experimental conditions no role of point defects was noted.     

Ion-beam erosion of carbon fibers of the composites

The results of experimental studies of the structural and morphological changes of the surface of carbon PAN fibers of a carbon-carbon KUP-VM (1D) composite as a result of high-dose irradiation (10¹⁸–10¹⁹ ion/cm²) with Ne⁺ and Ar⁺ ions with an energy of 10–30 keV are presented. The threshold values of radiation damage, resulting in an amorphization of the PAN carbon fibers at room temperature and ion-induced crimping at temperatures greater than the annealing temperature of the radiation damage, are determined.     

Kinetics of a bimolecular chemical reaction in the liquid phase with association of both reactants

Mathematical modeling of a bimolecular chemical reaction in the liquid phase was carried out taking account of association of both reactants. The formally simple chemical reaction is thus transformed into a multistage process, which results in the formation of temporal dissipative structures. It was found that, apart from the usual dynamic modes, there appear oscillations of the concentrations of intermediates, characterized by two considerably differing periods.     

Temperature dependences of the ion-electron emission of glassy carbons under 30-keV argon ion irradiation

The temperature dependences (?200°C < T ≤ 350°C) of the ion-induced electron emission yield γ and the structures of modified surface layers have been studied experimentally for SU-850, SU-1000, SU-1300, SU-2000, and SU-2500 glassy carbons under high-dose 30-keV Ar⁺ and N ₂ ⁺ ion irradiation. Glassy carbons manufactured using a relatively high heat-treatment temperature T _ht exhibit a stepwise increase in the electron yield at certain annealing temperatures T _a. The same behavior is observed for graphitized carbon materials. For low-temperature glassy carbons, the electron yield exhibits a monotonic increase with increasing irradiation temperature. The observed differences are related to the occurrence of different structural types of fullerene-like nanoparticles in the low-and high-temperature glassy carbons.     

Mutual Influence of Ligands and Reactivity of Gd and Dy Acidophthalocyaninate Complexes

The results of the kinetic study of dissociation of Gd(III) and Dy(III) complexes with phthalocyanine of the composition (X)LnPc (X is single-charged acido ligand) with isolation of macrocyclic ligand depending on the temperature, composition of mixed ethanol–acetic acid solvent, and the nature of acido ligand are presented. The total kinetic equations, the rate constants, and activation parameters of dissociation reaction are determined. The stoichiomeric mechanism is suggested for the complex dissociation involving the limiting elementary reaction between acetic acid molecule and the complex that occurs as the chelate salt (X)LnPc or the outer-sphere complex [(HOAc)LnP]⁺X^–. The state of metal phthalocyaninate at the reaction slow stage is shown to be determined by the electronic structure of the metal cation, the strength of binding of the axial ligand, and by its cis-effect on the metal bonds with macrocycle.     

Mathematical Simulation of Low-Frequency Mechanical Action on Bimolecular Reaction Kinetics in a Structured Liquid

A mathematical model of the physicochemical processes that occur under low-frequency mechanical action on bimolecular reaction kinetics with consideration for the association of reagents is presented. As a result of the mathematical simulation, special features of the kinetics and stability of the reaction modes were established. It was shown that, in a structured liquid, a formally simple reaction occurs as a complex process with the appearance of bistability regimes, the formation of a temporal dissipative structure, and the complex structure of intermediate concentration oscillations. The possibility of controlling transitions from stable to unstable reaction conditions and vice versa under changes in the external action amplitude was demonstrated.