A method for increasing the production efficiency of ultra-lightweight refractory products is proposed, by optimizing the technology for preparing foam, which allows to release the products from the forms immediately after they are installed for drying. The plastic-viscous characteristics and stability of the foam can be increased by its mineralization, i.e. by introducing fine mineral substances into the foam-forming solution
Keywords: foam mass, mineralization, ultimate shear stress, plastic-viscous characteristics, ultra-light refractories, aluminum-potassium alum
The paper reveals the problem and causes of the formation of fetid compounds in the systems of transportation and wastewater treatment. Various methods used at the moment to eliminate and neutralize unpleasant odors, as well as a number of measures to clean the air from fetid compounds are considered. A new method is described to prevent the formation of odors of fetid compounds in wastewater transportation and treatment systems and a device for its implementation using low-intensity cavitation. The scheme of the device for sewage treatment from smells of fetid compounds. The principle of operation of this installation is described.
Keywords: fetid compounds , air purification, biological purification, low-intensity cavitation
The results of the development of a polymer fire-resistant heat-insulating coating containing waste from electrochemical production for thermal insulation of hot metal surfaces of industrial equipment and building structures, working surfaces of pipelines are presented. The coating is developed on the basis of acrylic binder, hollow carbon microspheres, antifoam, pigment and flame retardant based on waste electrochemical production - galvanic sludge. The use of hollow carbon microspheres as a filler in the amount of 14.0 to 38.0 wt. including reduces the thermal conductivity of the coating, and the use as a flame retardant additive, pre-dried and finely ground galvanic sludge in an amount of 5 to 15 wt. h., gives the cured heat-insulating coating fire-resistant properties. Studies have shown that the use of this composition allows you to get a polymer heat-insulating coating with good physico-mechanical and flame retardant properties, while another problem is solved - the safe disposal of galvanic sludge.
Keywords: polymer heat-insulating coating, waste from electrochemical production, flame retardant, hollow carbon microspheres, galvanic sludge, fire resistance, safe disposal
Known mechanisms of relaxation of tension in the film at small misfit deformation: the formation of waviness on the initially flat free surface of the film (the instability of the Asaro-tiller-Grinfeld); nucleation of misfit dislocations at the interface film-substrate; a redistribution of atoms near the wavy surface of the film due to the reduction of elastic energy in napylenie on a substrate a semiconductor film; reducing surface energy of the film by increasing its thickness; formation of nanoscale isolated Islands on the surface of the film (Stransky-Krastanov growth); due to the formation of misfit twinning. This paper presents the results of calculations taking into account these factors for different values of the parameters of the film and Islands.The equilibrium conditions of a two-component elastic layer containing mismatch dislocations are investigated. A nanometer-thick SiGe film on a Si substrate and nanometer-sized SiGe Islands on a wetting layer are considered. The uneven distribution of Ge in the sample volume is taken into account. Three-dimensional models of a flat film with dislocation and Islands are constructed. The calculation of elastic deformations is performed using the finite element method. Approximating formulas and iterative algorithm are used to calculate the Ge distribution in the film. According to the results obtained, the uneven distribution of Ge provides relaxation of elastic energy in the alloy, and Ge atoms are concentrated on the protrusions of the disturbed surface of the film and in the vertices of the Islands. Taking into account the heterogeneity of the Ge distribution in the samples has a significant impact on the growth of islets (stable growth occurs with smaller islets) and undulation on the free surface.
Keywords: thin film, heteroepitaxy, Ge, SiGe, misfit dislocations, elastic energy density, finite element method
Currently, the problem of increasing the efficiency of managing resource-intensive tasks in distributed computing systems is quite acute. Analysis of existing task dispatching algorithms for traditional computing systems showed the limitations of using these methods in heterogeneous systems, as a result of which significant delays can occur between task switching.A functional mathematical model for estimating the workload of distributed computing systems is proposed, based on determining the probability of downtime of the processing center as a criterion for assessing the system load. Using this model will provide increased efficiency in managing resource-intensive tasks in distributed computing systems.
Keywords: mathematical model, distributed computing system, processing center, loading
The paper is based on a review of the scientific publications released from May through October 2019, the greater part of which, namely 14 papers, is included in the Web of Science scientometric database. The authors of the papers analyzed explore the construction industry problems over the past 5 years. The foreign studies listed in the reference section were based on the analysis of reviews falling in the above-mentioned timeline. The purpose of this paper is to identify the problems hindering the implementation of BIM technologies in the construction sector, not only in the foreign countries, but also in Russia.
Keywords: building information modeling, construction organizations, critical problems, external factors, absence of organizational support
The problems of the operation of buildings on subsidence soils of the Rostov region are considered. A brief analysis of the methods used to consolidate the soil. Concrete examples of the use of cementation and silicatization of soil bases in the development of reconstruction projects for buildings in the cities of Shakhty and Taganrog, Rostov Region are given. An integrated approach to the choice of technology for fixing the soil base of reconstructed objects is proposed, which provides for the simultaneous consideration of the following factors: - basic physical and mechanical properties of soils; - mineralogical composition of soils; - change in the state of the soil base during the operation of the building (local decompression, erosion, chemical and mechanical suffusion, etc.); - chemical composition and groundwater level, forecast of their change; - terrain, the danger of activation of landslide processes; - the presence of retaining walls and other retaining structures in the zone of influence, assessment of the loads on them in the process of consolidation; - the technical condition of building structures of the building, including its underground part and the blind area; - the status of the reconstructed object. With special care and precaution, it is necessary to choose the technological and design parameters of soil consolidation for cultural heritage sites of federal or regional significance; - technical and economic indicators.
Keywords: subsidence of soils, strengthening of soils, fixing of soils, cementation, silicatization, Geology, construction, cultural heritage object
The influence of socio-economic factors creates the need for the use of new design solutions with the introduction of advanced methods, as well as technical means in design. The article discusses the basic algorithmic methods that define a new approach in architectural practice. Using the experience of designing as an example, the advantages of using algorithmic software systems were determined, which are responsible for increasing the quality characteristics of the final result, increasing the value of the project due to the limitless possibilities of graphical presentation by program algorithmic modeling methods.
Keywords: algorithmic methods, computational design, shaping, Galapagos plugin, script, simulation
The results of the development of a polymer coating with high heat-insulating and fire-resistant characteristics containing waste from galvanic production are presented. This coating is designed for thermal insulation and fire protection of concrete and metal surfaces of various building structures and industrial equipment. The coating is developed on the basis of siloxane rubber, K-18 catalyst, hollow carbon microspheres and industrial waste - galvanic sludge used as a flame retardant. The use of hollow carbon microspheres provides an increase in the strength and thermal insulation properties of the coating. The use of galvanic slurry in the amount of 5-15 parts by weight it allows to obtain the effect of self-extinguishing of the heat-insulating coating, reducing the burning time without compromising the operational properties - strength, adhesion, while solving another important problem - the safe disposal of galvanic sludge. Studies have shown that the use of this composition allows you to get a relatively inexpensive, but quite effective polymer coating with good thermal insulation, flame retardant and physico-mechanical properties.
Keywords: polymer coating, siloxane rubber, hollow carbon microspheres, galvanic sludge, thermal conductivity, strength, self-extinguishing effect, safe disposal
In the framework of ensuring a high level of products and in order to increase its competitiveness, the development and implementation of quality management systems at the enterprise can be considered an urgent task. Among the main processes of the QMS, a special place is taken by corrective and preventive actions. Management of this process, in turn, requires regular evaluation of the effectiveness of these activities. The article provides a methodology for evaluating the effectiveness of corrective and preventive actions in the production of solid medicines.
Keywords: corrective actions, preventive actions, unplanned non-conformities, non-conforming products, efficiency analysis
The largest cities of Russia have problems with the development of rapid transit passenger transport. A good solution to the problem is to replace the tram lines with rapid transit tram lines or light rail (LRT). One of the conditions of a light rail transit is to increase the distance between stopping points. A review of the literature shows that the question of the effect of the distance between stopping points on the tram speed is insufficiently studied. The aim of the study is to determine the relationship between the tram speed and the distance between the stopping points of the light rail system. The research method is simulation at the micro level in Aimsun. The study considered the speed limit, stopping time at stopping points, delays due to signalized intersections. Based on the simulation results, a relationship between the tram speed and the distance between stopping points was determined. The obtained relationship is of practical value and can be used for LRT planning and management in cities.
Keywords: high-speed tram, light rail, organization of the movement of trams, speed of communication, stop point, simulation
A large number of power receivers with non-linear current-voltage characteristics with a pulsed mode of operation appeared in residential buildings, which leads to the generation of 0.38 kV higher harmonic current components into the electric network, large values of these harmonics lead to a deterioration in the shape of the network voltage curve. The purpose of the work is to study the harmonics of current generated by electrical receivers of residential buildings, and their influence on the coefficient of non-sinusoidality of the network voltage of 0.38 kV. It has been established that the greatest negative impact on the electric network is exerted by electronic devices with switching power supplies, such as PCs, laptops and netbooks, as well as dishwashers and LED lamps with a socle E14 and E27, whose total harmonic current component coefficient is 85% ≤ THDI ≤ 205%. In the Matlab Simulink program, a simulation model of a 0.38 kV network of a residential building is simulated, which allows the study of the total distortion coefficient of the current KI and voltage KU in the ASU. With the installed non-linear load power more than double the linear load, the coefficient of non-sinusoidality of the voltage in the network of 0.38 kV may exceed the values established by GOST 32144-2013.
Keywords: power supply system, electric network, quality of electric energy, voltage harmonics, current harmonics, electromagnetic compatibility, power receiver
This article focuses on solving the urgent task of forecasting hazardous mining zones by determining the position of local centers of tension in a processed coal seam. The relevance of this task is confirmed by the fact that the intensification of mining processes inevitably leads to an increase in the risk of hazardous production situations, such as rock blows, sudden coal and rock emissions, etc. The most dangerous for the manifestation of rock strikes are the protrusions of the edge sections of the coal seam, intersection and pairing workings. Shockproof activities regulated by the normative documents, are not always sufficiently effective. To solve this problem, authors propose an approach that allows you to quickly determine the position of local centers of tension, taking into account the influence of the worked out space. The authors developed an integration grid, in the construction of which the division of the entire area into elementary sections is performed in such a way that the influence of the weight of the roof rocks over each section is the same. To implement this approach, the influence function of the worked out space is introduced in the form of the equation of the reference rock pressure diagram. Based on the results of numerical simulation of the stress-strain state of the geomassiv, an exponential dependence is obtained, which allows one to determine the concentration coefficient of vertical stresses for points on the plot of reference rock pressure. According to the values of vertical stresses calculated for each point of the integration grid, it is possible to predict the stress-strain state of the geomassiv and justify the need for shockproof measures. The application of the proposed approach will allow the rapid forecasting of hazardous areas and significantly reduce the cost of shockproof measures.
Keywords: modeling, geomassive, coal seam, integration grid, forecasting, vertical stresses
The article describes an approximate analytical method for calculating the humidity regime of multi-layer building enclosing structures. The novelty of the proposed method consists in using an analytical dependence to determine the position of the possible condensation plane obtained as a result of the study of the function representing the difference between the partial pressure of water vapor in the considered section of the enclosure structure and the partial pressure of saturated water vapor at the extremum. The results of calculating the humidity regime of the external wall of a residential building under construction in the city of Samara, using a monolithic bespeschany expanded clay concrete with a density equal to 600 kg/m3, are presented. The assessment of moisture accumulation in the considered external wall both for the annual period of operation of the building, and for the period of months with negative temperatures, showed compliance with the regulatory requirements for heated rooms
Keywords: enclosing structure, humidity mode, moisture transfer, vapor penetration resistance, water vapor, condensation plane
The article is devoted to the issue of improving the environmental safety of highly urbanized territories. The article presents the results of field measurements of pollutants into the atmosphere from gas stations within the urbanized territories of cities of the Russian Federation. The largest part of the allocation of oil product vapors entering the local aspiration systems is associated with the operations of filling and emptying fuel storage tanks at gas stations. The results of field measurements of the values of hydrocarbon concentrations obtained on the basis of the values of maximum permissible concentrations of ingredients are presented. The conclusion is drawn on the feasibility of environmental protection measures to reduce emissions when finding housing in the border area of the sanitary protection zone (SPZ) of gas stations. To reduce emissions from gas station sources, it was proposed to equip the gas aspiration system of the gas feeling tank with an improved design of the absorption device. In order to reduce waste generation as a working agent in such devices, it was proposed to use wastewater with a certain amount of oil products from a local gas station treatment device. This approach also allows to reduce the negative anthropogenic impact of gas stations in terms of the formation of additional amounts of waste generated during their operation. Successful tests have shown reliable and efficient operation of the pilot plant with the proposed apparatus.
Keywords: gas station, gasoline, emission, atmosphere, concentration, hydrocarbons, aspiration, reservoir, pollution, oil product, pollution, water