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  • Methods for the synthesis of LaMnO3 (Review)

    "This review covers various methods of synthesis LaMnO3 ferroics. The general analysis of the solid-phase synthesis reactions methods and wet methods (sol-gel, sorption, co-precipitation) are carred out. The original results of LaMnO3 syntheses from various precursors by means of the in situ method are showned. The advantages and disadvantages of different methods of synthesis are determined. The analysis of synthesis LaMnO3 ferroics published data is shown:
    - the structure formation of LaMnO3 in perovskite-type phases occurs at different temperatures, depending on precursors states;
    - LaMnO3 perovskite phases differ in symmetry and unit cells parameters at room temperature, depending on the preparation conditions;
    - the highest synthesis temperature of LaMnO3 are typical for solid phase reactions method (950-1050 ° C), the lowest - for wet synthesis methods (500-700 ° C);
     - the synthesis conditions effect the stoichiometry of LaMnO3 for oxygen content.
    Our studies of structure formation processes of LaMnO3 by in situ method are allowed to define the role of precursors states at synthesis of solid phase reactions methods, adsorption, co-precipitation and sol-gel mixtures.
    It is determined that in samples prepared by wet chemical methods, the formation processes of  LaMnO3 perovskite phases occur at lower temperatures than by solid phase reaction (sol-gel precursor - 500 <T <600 ° C; precursors obtained by coprecipitation and sorption methods - at 600 <T <700 ° C and 700 <T <800 ° C, respectively).  

    Keywords: ferroics, LaMnO3, X-ray diffraction, solid-phase synthesis, sol-gel synthesis, sorption, co-precipitation

  • The choice of boundary conditions for the simulation of the temperature field of soil

    The existing methods of calculation of the annual change in soil temperature. Identified areas of their application and the possible deviations from reality. The requirements to the boundary conditions of the calculation. Defines the principles of the choice of initial conditions. The preconditions for the development of a universal method of calculation.

    Keywords: heat pump, renewable energy, solar radiation, transient mode, soil

  • Development of physical model of process of air pollution for a site of charging of accumulators at the motor transportation enterprises

    In article negative impact of objects of municipal economy on an urban environment, on the example of a site of charging of accumulators of the motor transportation enterprise is considered. The physical model of process of pollution of the air environment is developed for a site of charging of accumulators on ATP. The description is given to basic elements of model (technological raw materials, processing equipment, etc.), participating in air pollution process.

    Keywords: the municipal economy polluting substance, process of pollution of the air environment, technological raw materials, processing equipment

  • The application of the theory of disperse systems for the description of the behavior of the toxic components of the flue and exhaust gases from stationary and mobile sources of urbanized territories

    Considers the most important sources of material pollution of urban territories. A comprehensive approach to studying properties of pollutants, based on the theory of disperse systems. Built block diagram of systematization of parameters that determine the behavior of contaminants from the position of theory of disperse systems. The dependence between the behavior of pollutant aerosol and parameters of its stability.

    Keywords: Contaminant dispersion system, the parameters of pollutant properties, stability of pollutant aerosol

  • The use of physical-energy approach to the description of air pollution factories concrete products and structures

    Considered relevant for the construction industry the problem of air pollution by dust. A significant level of airborne dust is typical for plants of concrete products and structures. A physical model of the process of mixing of air pollution department, which includes the main stage of the contamination: education, allocation and distribution of pollutants. Ustanovnleno that the main objects of the physical model are contaminant technological raw materials, manufacturing equipment, the workplace air and the ground layer of the atmosphere.

    Keywords: Contaminant technological raw materials, manufacturing equipment, workplace air, the physical model of air pollution

  • The investigation of properties of gas sensitive materials based on SiO2SnOxCuOy thin films used in gas sensors for multisensory air monitoring system

    The establishment of automated air monitoring systems is a promising way of the air monitoring devices development. The comparative analysis of literature has shown that thin films based on semiconductor metal oxides are effective and widely used material for air monitoring systems creation. In order to create effective and more sensitive sensors it is important to research processes that occur on the surface of the gas sensitive material when it contacts with different substances. The processes that proceed on the surface of gas sensitive material based on SiO2SnOxCuOy during the interaction with molecules of nitrogen dioxide. Quantum chemical calculations have shown that there are three possible mechanisms of interaction between the molecules of nitrogen dioxide with a surface of gas sensitive material.

    Keywords: multitouch system of the monitoring, gas-sensitive material, molecules of dioxide of nitrogen

  • The development of gas recognition technique using multysensor system for air monitoring

      The problem of air quality control is relevant at the present time. There are a lot of different devices and methods of air monitoring. The promising devices for air monitoring are automated air monitoring systems functioning in real time regime. The basic part of such system is a chemical gas sensor. Gas sensors can be combined into the arrays or so called multisensory systems to increase their effectiveness. Sensor arrays using semiconductor sensors based on SiO2CuOx, SiO2SnOxCuOy, SnOxZrOy, silver-polyacrylonitrile thin films made at department of chemistry and ecology have been investigated in this work. As a result of sensors signals processing gas recognition technique has been developed. The recognition of ammonia, nitrogen dioxide, chlorine has been made.

    Keywords: monitoring, massifs of sensors, semiconductor sensors of gases

  • Investigation properties of composite material for high sensitivity nitrogen dioxide sensors

      We have investigated electrical and gas sensitive properties of gas sensor based on carbon nanotubes (CNT) and carbon nanotubes modified by metal oxides (such as tin oxide and silicon oxide).  Also we  have find out that modification of  CNT by  metal oxides helps to  improve film`s adhesion to substrate, decrease electrical resistance, recovery time, working temperature , enhance gas sensitivity in comparison with sensitive elements based  only on CNT or metal oxides. Moreover experimental results showed that properties of composite material depend on concentration correlation of solutions. As a result we can get highest sensitivity of sensor element by choosing optimal relation between concentrations of solutions.

    Keywords: Сarbon nanotubes, modification, tin oxide, silicon oxide, gas sensor

  • Application of neural networks to build prediction model of urban air pollution

      Neural network model of distribution of pollutant in the atmosphere of the city of Taganrog has been developed on the basis of monitoring data, meteorological information and calculation made by software «Ecolog-gorod». The results of the work of model have been visualized in software ArcGis. Distribution maps of nitrogen dioxide has been built under the conditions of eight directions of wind, two wind speeds and two temperature ranges.

    Keywords: Neural network, prediction model, urban air pollution

  • Research of point surface defect’s composition and structure on casts of stainless steel when casting by investment pattern

    Results of research the ties of refrectory oxide, which form in the course of filling with stainless steels, and specific point defects impairing casts of stainless steel.

    Keywords: quartz mould, chromium steel, oxides, chemical analysis, physicochemical interaction

  • The study drip ash from galvanic bath with the application of chromium coatings

    In article are considered questions of the study of the composition of the drip of ash from galvanic bath with the application of chromium coatings, the results of research concentrations of chromium above the surface of the bath and in the working zone depending on the height above the mirror electrolyte

    Keywords: working zone, galvanic bath, drip ash, chrome, local capturing

  • Study of the temperature influence of internal air on temperature distribution of the heat-insulated floor surface.

    It is considered the dependence of the operation mode of floor radiant panel heating systems depending on the design parameters for the internal air  

    Keywords: panel-radiant heating, heat-insulated floor, parameters of the internal air

  • Analysis of the condition of atmospheric air in industrial cities of the Rostov region

    The state of the atmospheric air in such industrial cities of the Rostov region, as Belaya Kalitva, Donetsk, Kamensk-Shakhtinsky over the last 10 years (2003-2012). Identified main pollution sources and priority pollutants. Analysis of the concentrations of pollutants in areas of concentration of industrial enterprises, on highways and in dwelling zones. It is established that industrial cities are specific «geochemical provinces», in which abnormally elevated concentrations of many chemical elements. On the background of the decrease of the role of industrial enterprises in the air pollution increases the role of motor transport  

    Keywords: Anthropogenous influence, industrial production, ecological situation, environment, an ecosystem, the industry, transport, pollution.

  • Competitiveness evaluating and analysis for different compressed air drying methods

    Evaluating of the compressed air drying competitive methods for wagon depots are given in the article. The criteria for evaluating of each method are defined. The considered compressed air drying competitive methods profiles are built. The wet condensation ability effectiveness increase ways are defined.

    Keywords: Compressed air drying, Competitive profiles, Wagon depot, Expert estimation

  • The development of some methods of the working area air purification from crushed limestone dust appearing during the cars’ dump

    The level of dust pollution appearing during the dump of cars loaded with crushed limestone is defined. The data on the composition of the dust particles dispersed into the air in the working area during the cars loaded with rubble dump is obtained. The scheme of experimental-industrial dedusting ventilation and the results of its tests are described.

    Keywords: system of dedusting ventilation, rubble, dust pollution