Information-statistical approach to inverse optical problem solution for 3D disperse systems with nano- and micro particles

Multiparameter analysis of simultaneous optical data for 3D disperse systems (consisted from nano- and/or microparticles of different nature) by information-statistical methods can help to estimate the share of different types of particles in mixtures. At the solution of inverse optical problem for unknown poly-component 3D DS, the comparison of measured parameters with the known ones from the set of mono-component 3D DS can help to identify the component content of the system under study. The approach was tested on the biomineral water mixtures of kaolin clay and bacterium coli bacillus with the help of the program based on the information-statistical theory. To solve the impurity optical recognition tasks, the Base of optical data for 3D DS is needed.

Modeling of colloidal systems in technological processes

The article describes the main methods of mathematical modeling of industrial free-dispersed systems. The method of constructing the regression equation by the method of linear and nonlinear installation of coefficients is proposed. The fundamentals of tensor and harmonic approaches to the analysis of disperse systems are considered, which allow optimizing the equations of material and energy balance in the conditions of industrial operation of dispersions.

IMPLEMENTATION OF THE DРIE METHOD IN TECHNOLOGIES OF OBTAINING STRUCTURED SYSTEMS

Within the framework of the work, experimental and laboratory studies of a complex of heat and mass transfer processes in multicomponent disperse systems that exhibit emergent properties have been carried out. The aim of the work is to determine the key factors that affect the properties of the final product, and bifurcation points for complex dispersed systems in terms of the mechanisms of structure formation. The authors determined the influence of key parameters such as the process temperature and shear stresses that arise in systems during processing in rotary-pulsating devices of the disk-cylindrical type. For systems with polyelectrolyte structures, the temperature ranges have been determined at which the intensity of the solvation process is maximum. The investigated multicomponent systems are sensitive to shear stress and the duration of its exposure. The limiting shear stresses are determined at which the destruction of structures begins and the system becomes fluid. Based on the results of the complex of works, a schematic diagram and a pilot plant for obtaining poly-component structured systems were proposed. Вatches of bactericidal sanitary-hygienic means and application medical-prophylactic means were obtained at the proposed installation and transferred for testing.

ENTROPY INFLUENCE ON THE DEPENDENCE OF THE NANOFLUIDS VISCOSITY ON TEMPERATURE AND SHEAR RATE

A Brookfield DV-II + Pro rotational viscometer was used to study the viscosity of 7 samples of concentrated nanodispersed systems (nanofluids) with a similar viscosity (6-22 mPa ∙ s), the particles of the dispersed phase in which are nanosized surfactant micelles and conglomerates from them. It was found that for 5 out of 7 studied reagents, there is a decrease in viscosity typical for dispersed systems with an increase in the shear rate, and their flow curves, that is, the dependence of the shear stress on the shear rate, correspond to the ideal plastic flow of non-Newtonian fluids. Moreover, with high reliability, R2 ≥ 0.999 is described by the Bingham equation with a small value of the limiting shear stress (less than 0.2 Pa). It is shown that all the studied reagents are also characterized by an increase in the activation energy of a viscous flow Е with an increase in the shear rate. As a result, a decrease in viscosity with an increase in shear rate, typical for disperse systems, including nanofluids, is provided by a more significant increase in entropy changes ΔS compared to Е. It has been substantiated that, depending on the ratio between the activation energy of viscous flow Е and the change in entropy ΔS, the viscosity of concentrated micellar dispersed systems with an increase in the shear rate can decrease, remain unchanged, and increase. The last two cases, not typical for disperse systems and nanofluids, were identified and studied using the example of two demulsifiers, RIK-1 and RIK-2, with a maximum of a very narrow particle size distribution at 160 ± 5 nm, corresponding to the size of a special type of very stable micelles Surfactant — vesicle.

Electrical Excitation Decay Time in Chains of Nanoscale Non-Point Dipoles

On the basis of a previously developed model of disperse systems containing non-point dipole particles self-assembled into chains inside a liquid substrate, the decay time of electrical excitations induced in dipoles by an external field is investigated. It was shown that when the external field is completely turned off (from 10−6 V / m to 106 V / m levels) at biologically significant low frequencies (for example, 13 Hz), the decay time of the excitations of nanoscale dipoles nonlinearly depends on the chain length. It was found that the decay time of excitations increases sharply (by four to five orders of magnitude), with an increase in the chain length more than 19–20 dipoles.

Application of pulsed and high-frequency electron paramagnetic resonance techniques to study petroleum disperse systems

The spectral and relaxation characteristics of “free” organic radicals (FR) and vanadyl-porphyrin (VP) complexes in various petroleum disperse systems (PDS) like bitumen, petroleum, their high-molecular components and solutions were studied using stationary (conventional) and pulsed electron paramagnetic resonance (EPR) techniques in two frequency ranges (X- and W-bands, with the microwave radiation frequencies of about 9 GHz and 95 GHz, respectively). The features of the pulsed approaches (electron spin echo, modulation of the electron spin echo signal decay, electronic relaxation times) and high-frequency EPR for PDS investigations were examined. W-band EPR allows to resolve spectrally the lines from the different paramagnetic centers and more accurately determine their spectral characteristics. It is shown that the electron spin echo can be observed at room temperatures even at high magnetic fields of 3.4 T demonstrating the potential of application of pulsed EPR techniques for the low-cost oilfield measurements. Analysis of the VP transverse magnetization decay curve permits to identify electron-nuclear interactions with the 14N and 1H nuclei in situ while in the EPR spectra these hyperfine interactions usually cannot be detected. It is found from the W-band EPR measurements that FR lineshape cannot be fitted with isotropic parameters in contrast to the established X-band results. The observed effect of increasing the rates of electronic transverse relaxation in asphaltenes is described in the framework of a model of spectral diffusion between the fast- and slow-relaxing paramagnetic centers in supramolecular complexes of asphaltenes.

GIANT DISPERSION OF DIELECTRIC PERMEABILITY OF THE DISPERSE SYSTEM IN AN ALTERNATING ELECTRIC FIELD. OVERVIEW OF APPROACHES TAKING INTO ACCOUNT PRESENCE OF A DOUBLE LAYER

This review analyzes two approaches to describing the polarization of disperse systems when an alternating electric field is applied in the general case. Polarization models of Trukhan and Dukhin – Shilov are considered. As a result of this review, it follows that the most preferable model, which makes it possible to significantly increase the rate of electrophoresis of the dispersed phase, is the Dukhin – Shilov model, in the implementation of which a giant dispersion of the dielectric constant of a heterogeneous dispersed system may appear if the condition of a thin double layer around non-conducting dispersed particles in a conducting dispersive medium.