Polarization of Fluorescence of Asphaltene Containing Systems

Formation of supermolecular structures in petroleum disperse systems is determined by interactions of asphaltenes. Petroleum systems are lyophilic oleocolloids with low polar dispersive media which is in dynamic balance with elements of disperse structure. Supermolecular scale of organization is most important for determining the macroscopic parameters. Levshin-Perrin equation for depolarization of fluorescence was modified for polydispersed systems. Interfacial tension coefficient of model asphaltene solution was calculated in a case of Volmer's function. For technogenic mixtures the temperature dependences of the sizes near the point of phase transition are presented. Enthalpy of asphaltene association per one molecule was calculated. Polarization degree together with macroscopic parameters correlates with appearance of asphaltene dispersed phase in system.     

Spectroscopy of resonant excitation of exciton luminescence of GaSe–GaTe solid solutions

The luminescence excitation spectra of localized excitons in GaSe_0.85Te_0.15 solid solutions have been investigated at the temperature T = 2 K. It has been shown that the excitation spectra of excitons with the localization energy ε > 10 mV exhibit an additional maximum M _E located on the low-energy side of the maximum corresponding to the free exciton absorption band with n = 1. It has been found that the shift in the position of the maximum M _E in the excitation spectrum with respect to the energy of detected photons increases as the energy of detected photons decreases, i.e., with an increase in the localization energy of excitons. Under the resonant excitation of localized excitons by a monochromatic light from the region of the exciton emission band, in the exciton luminescence spectrum on the low-energy side from the excitation line, there is also a maximum of the luminescence (M _L ). The energy distance between the position of the excitation line and the position of the maximum in the luminescence spectrum increases with a decrease in the frequency of the excitation light. The possible mechanisms of the formation of the described structure of the luminescence excitation and exciton luminescence spectra of GaSe_0.85Te_0.15 have been considered. It has been concluded that the maximum M _E in the excitation spectrum and the maximum M _L in the luminescence spectrum are attributed to electronic–vibrational transitions with the creation and annihilation of localized excitons, respectively.     

The observation of fluctuations of relict radio emission as a method of distinguishing adiabatic perturbations from other forms of perturbations of material density in the universe which lead to galaxy formation

A special periodic dependence of the amplitude on the mass is inherent in adiabatic density perturbations. A detailed investigation of the fluctuations of relict radiation may lead to a clarification of the nature of primary density perturbations with which the formation of galaxies and clusters of galaxies is associated.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 15, No. 2, pp. 161–171, February, 1972.     

Petroleum resins adsorption onto quartz sand: near infrared (NIR) spectroscopy study

In this paper we have tried to evaluate adsorption parameters of petroleum resins. Near infrared (NIR) spectroscopy is applied for resins bulk concentration evaluation during adsorption process. NIR experimental scheme and parameters are provided. NIR spectra range of 9000-13,000 cm(-1) is chosen. Quartz sand (0.2-0.8 mm fraction) is used as adsorbent; benzene is used as solvent. Different approaches of "NIR spectra-resins concentration" calibration model building are discussed. Partial least squares (PLS) regression method is used. Langmuir model is chosen for experimental data fitting. Combined usage of kinetic and isothermic data gives us ability to evaluate the maximal adsorbed mass density, the equilibrium constant of adsorption, and the rate constants of adsorption (and desorption). The rate constants of resins adsorption and desorption are found to be concentration independent.     

A COUPLED FLUID-STRUCTURE ANALYSIS FOR 3-D INVISCID FLUTTER OF IV STANDARD CONFIGURATION

A three-dimensional non-linear time-marching method and numerical analysis for aeroelastic behaviour of an oscillating blade row is presented. The approach is based on the solution of the coupled fluid-structure problem in which the aerodynamic and structural equations are integrated simultaneously in time. In this formulation of a coupled problem, the interblade phase angle at which a stability (or instability) would occur is a part of the solution. The ideal gas flow through multiple interblade passage (with periodicity on the whole annulus) is described by the unsteady Euler equations in the form of conservative laws, which are integrated by use of the explicit monotonic second order accurate Godunov-Kolgan volume scheme and a moving hybrid H-H (or H-O) grid. The structure analysis uses the modal approach and 3-D finite element model of the blade. The blade motion is assumed to be a linear combination of modes shapes with the modal coefficients depending on time. The influence of the natural frequencies on the aerodynamic coefficient and aeroelastic coupled oscillations for the Fourth Standard Configuration is shown. The stability (instability) areas for the modes are obtained. It has been shown that interaction between modes plays an important role in the aeroelastic blade response. This interaction has an essentially non-linear character and leads to blade limit cycle oscillations.     

Calculation of Dipole Moment of Fractal Asphaltene Cluster

Computer simulation has been used to investigate the cluster formation of the asphaltenes. Asphaltene nanoaggregates, forming a cluster, possessed permanent dipole moments. The influence of various factors, namely, temperature of the medium, size and dipole moment of the nanoaggregates, on the dipole moment of the asphaltene cluster was studied. The orientation interactions between the nanoaggregates were demonstrated to rise with increasing specific dipole moment of the nanoaggregates. It is has been found that the dipole moment of the asphaltene cluster varies according to power law in relation to the number of the nanoaggregates, forming the cluster.     

Cluster formation in dispersion systems: Oil and micellar systems

Solutions of hydrated reversed micelles and mixtures of distillate cracking residue and light catalytic gas oil are studied by the methods of correlation spectroscopy of scattered light and polarized fluorescence, respectively. The temperature dependences of the particle size of the disperse phase are obtained. It is found that the particle size increases with temperature in the range from room temperature to the critical temperature, which depends on the composition of the system under investigation, at temperatures above the critical temperature, the particle size decreases. These dependences can be explained by the formation of clusters from particles of the disperse phase at temperatures below the critical temperature and subsequent destruction of these clusters. Therefore, the structures of model (micellar) and natural (oil) disperse systems are compared for the first time, and the correlation between their behavior upon heating is revealed.