The global-in-time existence of a classical solution for some free boundary problem

The article addresses the issue of whatFree (unknown) boundary problems for differential equations are among the most difficult in the theory of partial differential equation

Highly-effective purification of air on the fibrous filtering nozzles

A series of experiments by air purification on fibrous filtering nozzles was made. It is experimentally shown that the fibrous filter can operate in a wide rate range. The degree of trapping of fine aerosols of glass was 99% at a linear rate of 0.01 m/s. the degree of capture decreased to 85% at the increasing of filtration rate up to 0.06 m/s. Dustiness of the air ranged from 3 to 5 g/m3 at the course of the experiment. Hydraulic resistance changed from 5 to 25 mm of water column. The calculated data of resistance and falling of pressure on fibrous filters are given; these data were received on the equations from various sources in comparison with experimentally obtained data. According to the results of series of experiments the amendment of the well-known Fuchsian equation is calculated for calculation of the resistance of fibrous air filter. This amendment considers a form and defects of surface of the fibers received by centrifugal-spinneret method

Control system of parameters of the azimuthal module

Analytical and experimental studies of the azimuthal module of two-component vibrational micromechanical gyroscope were conducted. It is shown that the micromechanical gyroscope is a system with distributed parameters. The frequency analysis is performed using software T-Flex. The influence of mechanical disturbances on the movement of azimuthal module in the form of translational and angular oscillations is shown; the natural frequencies of the azimuth are defined

Numerical Solution of Rare Metal Leaching Problem

It is well known that a lot of chemical and physical processes take place on the surfaces of interaction between solid and li quid substances. These processes include a very important technological process of uranium, nickel, copper, precious metal and other solid compound extraction - in-situ leaching. In this article we will rely on the mathematical description of these complex systems proposed by A.M. Meirmanov, where the main idea is the presence of new conditions on a free (unknown) boundary between liquid and solid phase

Physico-chemical Modification of the Fibrous Filter Nozzles for Purification Processes of Water and Air

A set of experiments to study physical and chemical modification of the surface of fibers is conducted to expand the area of their application for purification of water, gas and air (including that in conditions of space). The possibility of modification of filter nozzles in the process of fiber formation by particles of coal of BAU type, copper sulfide and silver chloride is experimentally shown. The fraction of the copper sulfide powder less than 50 microns in size was crushed in a spherical mill; it was deposited on fiber at air temperature of 50° C and powder consumption of 0.5 g/l of air. The resulting material contained 6–18 CuS particles per 1 cm of the fiber length. An effective bactericidal fibrous material can be produced using rather cheap material – CuS and relatively cheap natural compounds of sulphides and oxides of heavy metals

Processing line for industrial radiation-thermal synthesis of doped lithium ferrite powders

The paper considers the issues of industrial production of doped lithium ferrite powders by radiation-thermal method. A technological scheme of the processing line is suggested. The radiation-thermal technological scheme enables production of powders with technical characteristics close to the required ones under relatively low temperature annealing conditions without intermediate mixing. The optimal conditions of the radiation-thermal synthesis are achieved isothermally under irradiation by the electron beam with energy of 2.5 MeV in the temperature range of 700-750 °С within~ 120 min

On the global-in-time existence of a generalized solution to a free-boundary problem

A problem with free (unknown) boundary for a one-dimensional diffusion-convection equation is considered. The unknown boundary is found from an additional condition on the free boundary. By the extension of the variables, the problem in an unknown domain is reduced to an initial boundary-value problem for a strictly parabolic equation with unknown coefficients in a known domai

Injection Process Control of the Well at the Hydrodynamic Research of Coalbed

This scientific work is devoted to the study results of water injection process into the well at the hydrodynamic research by using the high pressure unregulated pump. The injection process should be accompanied by the retention of some hydraulic parameters at constant level during some time. Various variants for use of mechatronic nodes for automatization of water injection process are considered. Scheme for reducing the load on the pump and equipment in hydraulic system and also for improving the quality control system with high accuracy is shown. Simulation results of injection process into the well at the pressure and consumption fixation and recommendations for the use of the proposed schemes depending on the technological process are given

Monitoring and Quality Control of Diesel Fraction Production Process

In this work the mathematical model of diesel fraction and atmospheric gasoil catalytic dewaxing process has been developed. Also the pattern of applying the created model to solving such problems as monitoring and quality control of diesel fraction production in the catalytic dewaxing process. It has been represented that to meet such challenges, the model should take into consideration thermodynamic and kinetic laws of hydrocarbon conversion on the catalyst surface, and instability factors that are specified by catalyst deactivation. The developed model allows controlling the quality of obtained diesel fraction depending on feed and temperature regime in the reactor. The value of model calculation absolute error does not exceed 2%, which corroborates the adequacy of the model to actual process. The computations using the model have shown that to provide the desired product yield (not less than 40% wt. of overall yield of the unit products) of programmed quality (cold filtering plugging point not higher than minus 34°C for winter diesel fuels and not lower than minus 40°C for arctic ones) at long-time catalyst operation (during 4 years), it is necessary to sustain the reactor temperature at the average level of 19°C higher than when working with fresh catalyst. This must be done to compensate catalyst activity loss due to its deactivation

LEDs based upon AlGaInP heterostructures with multiple quantum wells: comparison of fast neutrons and gammaquanta irradiation

The paper presents the research results of watt and volt characteristics of LEDs based upon AlGaInP heterostructures with multiple quantum wells in the active region. The research is completed for LEDs (emission wavelengths 624 nm and 590 nm) under irradiation by fast neutron and gamma-quanta in passive powering mode. Watt-voltage characteristics in the average and high electron injection areas are described as a power function of the operating voltage. It has been revealed that the LEDs transition from average electron injection area to high electron injection area occurs by overcoming the transition area. It disappears as it get closer to the limit result of the irradiation LEDs that is low electron injection mode in the entire supply voltage range. It has been established that the gamma radiation facilitates initial defects restructuring only 42% compared to 100% when irradiation is performed by fast neutrons. Ratio between measured on the boundary between low and average electron injection areas current value and the contribution magnitude of the first stage LEDs emissive power reducing is established. It is allows to predict LEDs resistance to irradiation by fast neutrons and gamma rays