Table of contents

In the article, in order to study the properties and composition of organic and inorganic components obtained from processing of waste "yellow oil" by alkaline purification of pyrogas from sour gases in the existing gas chemical complexes in Uzbekistan and to determine its practical application, they were divided into components for the first time. The hydrocarbon composition of the oily part of the separated compounds has been studied using the gas chromatography-mass-spectrometry analysis method. Based on the results of the gas chromatography-mass-spectrometry analysis, the volumetric quantities of individual components were determined. Based on the results obtained, the areas of application of the oily part (as thickeners, fillers and additives) were studied, they were exposed to different functional groups, and preliminary data were obtained on the possibility of obtaining surfactants and raw materials for the paint industry by chemical reactions. Subsequent research has identified tasks that need to be addressed.

Development of numerical methods for calculating the movement of gas-dispersed flows in vortex and inertial separators, creation of devices with counter tangential and flows of increased dust collection efficiency, determination of the optimal profile of corrugated channels in order to minimize the release of droplet moisture from inertial separators.

Passenger and accompanying cargo-passenger maritime transportation on the Baltic Sea acts as systematic elements of the Baltic transnational macro-region. Ships that meet various environmental requirements today operate the ferry routes. The task of ecological safety assessment when introducing new ferry routes takes on special urgency. The paper contains analytical data of the marine ferry transportation industry, the main trends of the industry development. The analysis of the main ferry companies is performed and the main variables for estimating the level of possible pollution of the Baltic Sea are determined. Models for calculation of navigation autonomy by taking into account dimensions of allowable sewage and dry garbage are given. Based on the performed analysis of intensity of operation of sea ferry lines the forecast of areas of the Baltic Sea in which there will be an increase of ecological load is made. The necessity of development of information-measuring system for the assessment of the ecological situation of the Baltic Sea on the main directions of the sea ferry lines is substantiated. The structure of information-measuring system for monitoring of ecological situation at performance of sea ferry transportations is offered.

The article presents a method for determining the mass conductivity coefficient of wood when extracting biologically active substances from it. To implement the method, there was an installation developed, the internal cavity of which is divided into two zones filled with liquids with different concentrations of the extracted substance. The installation zones are separated by the investigated wood material. The determination of the mass conductivity coefficient is made according to the equation obtained from Fick's first law. As an approbation of the proposed method, we carried out studies on the mass conductivity coefficient of larch wood during the extraction of dihydroquercetin from it with a water-ethanol extractant and arabinogalactan with distilled water. As a result of experimental data processing, mathematical dependences of the larch mass conductivity coefficient during the extraction of dihydroquercetin and arabinogalactan on the process temperature were obtained, which can be used in mathematical modeling in order to optimize the operating parameters of the process.

In a solid solution of Ho_xMn_1-xS, the magnitude of the electric charge versus the voltage is investigated in a quasi-stationary electric field at frequencies of 0.003 Hz, 0.01 Hz and 0.1 Hz in the temperature range of 80-500 K. The temperature intervals phase synchronism of current and voltage are established. The temperatures of extremes with the maximum electric charge in the sample Ho_xMn_1-xS are found.

The paper considers the reflection of a circularly polarized light wave from a periodic nanostructure. The method of characteristic matrices was used to calculate the ellipsometric parameters ρ₀ and Δ of reflected light. It is shown that a wave initially polarized in the left circle changes polarization upon reflection, turning into an elliptically polarized wave. The results obtained for an ideal periodic medium are compared with the results of reflection from a periodic medium with a single defect - the upper layer of the original periodic medium is replaced by an absorbing dielectric layer. The analysis showed that the spectral dependences of the ellipsometric parameters for two structures, periodic and defective, differ significantly. In the range of wavelengths λ from 0.4 μm to 0.6 μm, the ellipsometric parameter ρ₀ for the considered periodic medium and the medium with a defect differ significantly from each other - where the maximum is for one medium, there is approximately the minimum for the other. In turn, the parameter Δ demonstrates a significant difference for the two structures in the wavelength range λ from 0.46 μm to 0.55 μm. The use of circularly polarized light demonstrates wide possibilities for studying defects in periodic nanostructures.

The article presents the results of experimental studies of changes in chaga physical parameters in course of aqueous extraction and a method for evaluating the efficiency of target components extraction based on changes in porosity for different zones of the fungus. Cutting-edge techniques and experimental plants were used in the research to determine the physical parameters of solid porous bodies: weight, volume, apparent volume, average density, apparent density, and porosity. It was found that four of the six physical parameters studied, i.e. weight, volume of the sample, apparent volume and average density had a negative change and two, namely apparent density and porosity, had a positive change. The percolation method was used to determine the quantitative yield of extractive substances for various zones of chaga. The largest values of parameter changes are typical for samples from the outer zone (sclerotium) and the fruit body, the smallest - for a sample from the inner layer of the chaga (the place adjacent to the tree trunk). This confirms the hypothesis of the greatest value of chaga elements related to the sclerotium and fruit body zones. A technique has been developed to determine the efficiency of the extraction process by the changes in chaga porosity. The dependence of the degree of extraction on changes in porosity for different layers of chaga has been established and mathematically described, which will allow for a comparative analysis of various extraction methods.

The work covers the compression strength, tensile bending and adhesion of a modified mortar developed by the authors based on local gypsum for the restoration of the Ismail Samani mausoleum and the Kalyan minaret. It has been shown that the strength of the mortar is sufficient and meets the requirements of existing building codes. The recommended compositions of the modified restoration solutions based on gypsum and their strength indicators have been identified. Compositions of modified restoration solutions that contribute to an increase in their water resistance and durability have been studied. In addition, a graphical analysis of the degree of strength of mixtures has been given and mathematical models have been developed. The optimal compositions of mixtures have been determined using mathematical modeling. Based on the results obtained, conclusions have been drawn.

This paper presents a study on the production of hydrogen and "green chemistry". The introduction introduces the terminology and historical data, followed by the defining principles that describe hydrogen production methods using natural gas, coal, water and biomass as feedstock. Some basics of "green chemistry" are also given. The next section provides an analysis of all hydrogen production methods, the results of the analysis are recorded in a table that allows you to identify the most environmentally friendly solutions. In the conclusion it is stated that the results of the study indicated in the table make it possible to assess the compliance of each of the 13 methods for producing hydrogen with the principles of "green chemistry", and the assessment and comments do not take into account the economic component of technologies, the main emphasis is on environmental protection.

The combustion of hydrocarbon fuels in the combustion chambers of diesel engines is preceded by processes of both physical and chemical transformations. The nature of the chemical transformations and their effect on the workflow are usually not taken into account. Meanwhile, their role in ensuring the efficiency of the workflow is very large. Chemical transformations in hydrocarbon fuels in combustion chambers cause the appearance of products capable of self-ignition under the influence of temperatures and pressures arising at the end of the compression stroke. The chain of these transformations ends with the formation of soot particles, the burning of which with abundant heat release in the form of radiant energy has a significant effect on the value of the indicator efficiency. The content and ways of influencing chemical transformations in fuel are considered, as well as the use of these transformations in increasing the combustion efficiency of fuels and increasing the indicator efficiency.

Relaxation phenomena are studied in Lu_xMn_1-xS solid solution using ultrasound in the temperature range of 80-500 K. The relaxation time of the ultrasound attenuation coefficient and relaxation maximum are determined. The dependencies of the attenuation coefficient of ultrasound on frequency and intensity are found. The current induced by ultrasound is determined.

The paper shows that nanocomposite materials based on a dielectric matrix with metal nanoparticles uniformly distributed in it can serve as a reference material in surface plasmon resonance spectroscopy. At certain concentrations of nanoparticles, such a nanocomposite, in contrast to the nanoparticles themselves, acquires the properties of a resonant material in which the real part of the complex permittivity takes negative values and, thus, the nanocomposite becomes surface-active. Surface plasmon polaritons can be excited at its boundary. For this reason, such a nanocomposite can be used as a reference material, similarly to the silver layer used, in the analysis of the optical properties of samples by surface plasmon resonance spectroscopy. The case of circular polarization of light incident on the structure under study is considered. The analysis of ellipsometric parameters of reflected light is carried out. The high sensitivity of the method is shown. In the range of incidence angles of 35° - 55°, the most pronounced angular dependence of the ellipsometry parameters is observed. Taking into account the analysis carried out, it is possible to suggest using these patterns in SPR spectroscopy to analyze materials in a structure containing a layer of the material under study and nanocomposites as reference elements, against which a sharp extremes of reflected light appears.