The article deals with obtaining RDF fuel based on solid municipal waste. The expediency of using this type of fuel in the cement industry is justified, since its combustion in cement furnaces has less impact on the environment due to the high temperature level of the process. The composition of RDF fuel by elements is analyzed. Due to the fact that this fuel from different sources has a difference in the heat of combustion of two times or more, the heat of combustion of RDF fuel for the middle zone of Russia was experimentally determined and its compliance with GOST R 55127-2012.
Keywords: solid municipal waste, MSW, Recycle Derived Fuel, RDF fuel, lower combustion heat, ash content, alternative energy source, colorimetric bomb
The temperature dependence of the contact angle of wetting allows of Pb-Na of different concentrations on substrates of Co-Cr, Ni-Cr and stainless steel substrate 25X18H9C2 was studied by the method of a lying drop. Measurements were carried out by the method of a lying drop from 359°C to 800°C in an atmosphere of pure helium grade A. It is shown that the value of the wetting angle decreases with increasing temperature, wetting thresholds are observed.
Keywords: wetting angle polytherms, wetting threshold, Co-Cr, Ni-Cr, 25X18H9C2 substrates
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 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
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
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
The article presents a program of comprehensive construction and technical expertise of the structures of an industrial building. The features of the construction and technical expertise of the structures of the agricultural warehouse of mineral fertilizers are described. An algorithm of the sequence of actions for the technical expertise of the structures of the object is developed. Measures have been developed to repair and restore the working condition of damaged structures
Keywords: construction and technical expertise, defects, bearing capacity, structural repair, property management
The emergence of digital X-ray machines and the development of cloud storage technology has led to the accumulation of a huge number of medical X-rays, in particular, chest x-rays - fluorography. The accumulated image bases after high-quality preprocessing can be used to train the deep convolutional neural networks that have received the most development in recent years, the trained network performs preliminary binary classification of the incoming flow of images and can be used as a radiologist assistant. For this purpose, it is necessary to adequately train the neural net-work to minimize errors of the first and second kind. A possible approach to improving the efficiency of neural networks, reducing the computational complexity and quality of image classification by the criteria is the use of auxiliary approaches of image preprocessing and preliminary entropy calculation. The article presents an algorithm for the X-ray image preprocessing, its division into fragments and the calculation of the entropy of individual fragments. During the preprocessing, the region of interest with lungs and the spine is selected from the entire image, constituting about 30-40% of the entire image, then the image is divided into a fragment matrix and the entropy of individual fragments is calculated using the Shannon formula, by analyzing individual pixels. By determining the frequency of each of the 255 colors, the total entropy is calculated. The use of entropy for detecting pathologies is based on the assumption of dif-ferences in its values for individual fragments and the overall picture of its distribution between images with the norm and pathologies. Statistical indicators are analyzed: standard deviation of error, variance.
Keywords: image entropy, fragments, deep convolutional neural network, machine learning, x-rays images, computational experiment, matrix of elements, image preprocessing, statistical analysis, binary classification
The reliability of the solar heating system with solar collectors was studied using the logical-probabilistic method by building a fault tree. The fault tree was obtained by sequentially detailing the events associated with failures of the solar heating system, as well as its elements. Events were taken into account: conducting test diagnostics of elements of the power supply system, repairing failed elements, failure of elements, reducing the power of solar collectors due to a decrease in the intensity of the solar radiation. The events were divided into two groups: events in which there is sufficient intensity of solar radiation for the hot water supply from the solar collectors, as well as events when the heating supply cannot be provided only due to the solar collectors. The last group of events was divided into two subgroups, within events caused short-term downtimes (at the time of switching) and long-term downtimes (at the time of replacing or repairing a failed system element). Long shutdowns are associated with the coincidence of failures, repair or diagnosis of one or more elements of the solar heating system. Expressions are compiled to calculate the probability of long downtimes, the probability of short downtimes, the probability of failure due to a decrease in the intensity of the solar radiation, and the total probability of failures. As a result of substituting the values of the reliability indicators of the elements of the solar heating system, the value of the total probability of failure during the year is 4.03∙10-5.
Keywords: solar hot water supply, reliability, solar collector, failure cause, reliability modeling
Various methods are used to scatter warm fogs: direct combustion of fuel in the fog; electric heating of the fog; introduction of streams or jets of warm and dry air into the fog; use of radiant energy for direct evaporation of hydrometeors; using explosions of highly heat-forming substances, etc. [4]. In this paper, artificially sprayed water droplets are used to scatter warm fogs. Refined calculations were made to investigate the possibility of fog scattering by artificial droplets. The model describes the fall of drops of radius r2 through the fog, consisting of drops of radius r1, the concentration of which is equal to n1. Detailed equations of gravitational coagulation are used taking into account the hydrodynamic interaction of droplets. The temporal characteristics of fog scattering (increase in visibility range) depending on the size of artificial droplets and their concentration are investigated. The size of artificial drops and their concentration, at which the maximum effect on fog scattering is achieved, are determined.
Keywords: scattering of warm fogs, meteorological visibility range, concentration of fog drops, fog water content, artificial influence on fog