Features of High-Viscosity Fluid Flow Through a Porous Medium Heated by Electromagnetic Radiation

Models describing the process of flow of a high- viscosity fluid through a porous medium heated by electromagnetic radiation are investigated analytically and numerically with allowance for the temperature dependence of the fluid viscosity and density. In addition to ordinary heating, the nonlinear electromagnetic heating regime associated with variation of the radiation absorption coefficient with temperature is considered.     

Intermolecular interactions of tetraanions of macrocyclic tetraresorcinol in H2O—DMF solutions

According to the data of pH-metric titration, macrocyclic tetraresorcinol (1c) dissociates stepwise with the abstraction of one, two, and four protons. Aggregation of tetraanions of 1c in H₂O-DMF solutions was detected by conductometry. The degree of aggregation increases as the size of the counterion decreases and the content of DMF in the solvent mixture increases.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1171–1174, May, 1996.     

PARALLEL ADAPTIVE SIMULATION OF A PLUNGING LIQUID JET

This paper is concerned with three-dimensional numerical simulation of a plunging liquid jet. The transient processes of forming an air cavity around the jet, capturing an initially large air bubble, and the break-up of this large toroidal-shaped bubble into smaller bubbles were analyzed. A stabilized finite element method （FEM） was employed under parallel numerical simulations based on adaptive, unstructured grid and coupled with a level-set method to track the interface between air and liquid. These simulations show that the inertia of the liquid jet initially depresses the pool＇s surface, forming an annular air cavity which surrounds the liquid jet. A toroidal liquid eddy which is subse- quently formed in the liquid pool results in air cavity collapse, and in turn entrains air into the liquid pool from the unstable annular air gap region around the liquid jet.     

Structure and characteristics of copolyamides based on ε-caprolactam and diisocyanates

The main supramolecular characteristics and the processing and service characteristics of copolyamides based on -caprolactam and hexamethylene diisocyanate were studied. The relation between the comonomer composition and supramolecular structure of copolymers was established.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 11, 2004, pp. 1891–1894.Original Russian Text Copyright © 2004 by Galibeev, Barnyagina, Kochnev, Arkhireev, Galimov.     

C60 fullerene, as ultraefficient quencher of singlet-excited adamantanone generated in photo-and chemiexcitation

Quenching of the fluorescence of Ad=O and its singlet-exited state (¹Ad=O*) generated in chemiluminescent reaction of adamantylideneadamantane-1,2-dioxetane (AdOOAd) termolysis by C₆₀ fullerene was detected and investigated. The “quenching efficiency-C₆₀ concentration” plots obtained from the decrease in the fluorescence and chemiluminescence intensities obey the Stern-Volmer law. The bimolecular rate constants (k _bim) were determined and the overlap integrals of the Ad=O fluorescence spectra with the C₆₀ absorption spectra (∫ _Ov) were calculated. Based on the nonconstant k _bim/∫_Ov ratios for different singlet-exited energy donors obtained for the ¹PAH*-C₆₀ systems (PAH are polycyclic aromatic hydrocarbons) and ¹Ad=O*-C₆₀, a conclusion is drawn that quenching of ¹Ad=O* by C₆₀ fullerene is a result of inductive-resonant singlet-singlet (major contribution) and exchange-resonant singlet-triplet (minor contribution) energy transfer. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1044–1046, May, 2007.