"Вестник МГСУ"

Subject: a groundwater filtration affects the strength and stability of underground and hydro-technical constructions. Research objectives: the study of one-dimensional problem of displacement of suspension by the flow of pure water in a porous medium. Materials and methods: when filtering a suspension some particles pass through the porous medium, and some of them are stuck in the pores. It is assumed that size distributions of the solid particles and the pores overlap. In this case, the main mechanism of particle retention is a size-exclusion: the particles pass freely through the large pores and get stuck at the inlet of the tiny pores that are smaller than the particle diameter. The concentrations of suspended and retained particles satisfy two quasi-linear differential equations of the first order. To solve the filtration problem, methods of nonlinear asymptotic analysis are used. Results: in a mathematical model of filtration of suspensions, which takes into account the dependence of the porosity and permeability of the porous medium on concentration of retained particles, the boundary between two phases is moving with variable velocity. The asymptotic solution to the problem is constructed for a small filtration coefficient. The theorem of existence of the asymptotics is proved. Analytical expressions for the principal asymptotic terms are presented for the case of linear coefficients and initial conditions. The asymptotics of the boundary of two phases is given in explicit form. Conclusions: the filtration problem under study can be solved analytically.

Mesh cover design, a multi-element design, which ensures the correct geometrical arrangement of the elements, is a very important task. The purpose of the given article is the development of a mathematical model for selecting the geometric parameters of wooden arches with mesh orthogonal grid with different input data. In this article three variants of design were observed. The main differences between them are in the relative position of longitudinal and transverse components. When performing static calculations of such designs in order to achieve their subsequent correct assembly, the following location conditions were observed: all the items must strictly match with each other without a gap and without overlap. However, these conditions must be met for any ratio of height to the arch span, the number of longitudinal members and the thickness of longitudinal members. Inverse problems also take place. In this case, the geometric calculation is not possible to vary the cross-section elements, and the stress-strain state of the cover is provided by varying the pitch of the transverse arches of the elements, on which the geometric calculation has no influence. All this determines the need for universal mathematical models describing any geometrical parameter of the designs needed for their geometrical calculation. The basic approach for the development of such models is the use of the known trigonometric formulas, giving a complete description of the desired geometry of the arch. Finally three transcendental equations were obtained, the solution algorithm of which using Newton’s method is presented in the MathCAD. The complexity of solving such equations using the proposed algorithm in the MathCAD is reduced to a minimum.

The increase in noise level at cities is increasing the requirements to functional interaction of road users - pedestrians and drivers - with the parameters of the environment as a leading component of Afferentation synthesis in the complicated complex of locomotive activity. City noise is one of the most widespread factors of unfavorable living and working conditions. The noise of high intensity provokes diseases, lowers labor activity. At present, many large cities pay much attention to electric vehicles. The authors present an analysis of the poor state of tram track in areas of high noise and vibration of car and under-sleeper base design. A negative effect of noise and vibration on the formation of urban areas environment is shown as well as the impact of these conditions on the person. The advantages of the application of electric transport are specified, noise displacement curve of railway and under sleeper base is plotted depending on the frequency of the applied load and the modulus of elasticity, as well as under sleeper base vibroacceleration depending on time. The authors offer a systematic study on the basis of a mathematical model of the sources of noise in the process of a tram motion.

The article describes the experimental methods of determining stress-strain state of elements and structures with a brief description of the essence of each method. The authors focus mostly on polarization-optical method for determining stresses in the translucent optical sensing models made of epoxy resins. Physical component of the method is described in the article and a simple diagram of a circular polariscope is presented, as well as an example of the resulting interference pattern in illuminated monochromatic light. A polariscope, in its most general definition, consists of two polarizers. The polarizers sandwich a material or object of interest, and allows one to view the changes of the polarity of light passing through the material or object. Since we are unable to perceive the polarity of light with the naked eye, we are forced to use polariscopes to view the changes in polarity caused by the temporary birefringence of our photoelastic materials. A polariscope is constructed of two polarizers, each set perpendicular to the path of light transmitted through the setup. The first polarizer is called the "polarizer", and the second polarizer is called the "analyzer". The method how the polarizer works is quite simple: unpolarized light enters the polariscope through the polarizer, which allows through only the light of its orientation. This light then passes through the material under observation, and experiences some change in polarity. Finally, this light reaches the analyzer, which, like the polarizer, only lets the light of its orientation through.

Pools play an important role in people’s life. They answer people’s demand in rest and improve their health. At the same time pools are rather important for industrial use, for example in construction industry. In order to solve different construction problems it is essential to investigate the influence of microclimatic parameters on construction materials and structures. For this aim pools are in demand as special test sites for construction materials and structures in different environmental conditions including the case of a direct water impact. The efficient use of pools presupposes the necessity of constant hydroclimatic contro: air humidity and temperature, water temperature, chemical composition of water and air. Classification of pools of different purposes is presented in the article. The author considers the main problems of operation of pools as objects with complicated air-and-water environment. The questions of maintaining optimal microclimatic parameters in a pool are considered. The necessity of use of the control system of a microclimate, its efficiency, profitability and social effect of its implementation is described. A mathematical model of the thermal mode of a pool area is constructed. The process of indoor temperature regulation in the pool is considered.

The analysis of the vibromolding process for engineering products was given. The design experimental model of concrete distributor of small scale was developed. The results of research on dynamic simulation of machinery were set out.

In the paper, the author proposes a mathematical model designated for the assessment of the ecological impact produced on the environment within the territory of the construction site. Integrated index EI (Environmental Index) is introduced as a vehicle designated for the evaluation of the ecological load. EI represents the intensity of the ecological load, or a generalized and optimized parameter reflecting the intensity of the anthropogenic impact of the construction site onto the natural environment.
The theoretical background of the proposed approach consists in an integrated methodology implemented in the system engineering of construction projects. A building system may be represented as the aggregate of all stages of construction works and participants involved in them. The building system is object-oriented, and it is implemented under the impact of pre-determined environmental factors. The core constituent of the building system represents a Production Technology Module (PTM), or summarized groups of processes. The model formula designated for the assessment of the intensity of the ecological load produced by the construction project onto the environment may be represented as follows:

Fire-resistance testing laboratory for building products and constructions
is a production room with a substantial excess heat (over 23 W/m3). Significant sources of heat inside the aforementioned laboratory are firing furnace, designed to simulate high temperature effects on structures and products of various types in case of fire development. The excess heat production in the laboratory during the tests is due to firing furnaces.
The laboratory room is considered as an object consisting of two control volumes (CV), in each of which there may be air intake and air removal, pollutant absorption or emission.
In modeling air exchange conditions the following processes are being considered: the processes connected with air movement in the laboratory room: the jet stream in a confined space, distribution of air parameters, air motion and impurity diffusion in the ventilated room.
General upward ventilation seems to be the most rational due to impossibility of using local exhaust ventilation. It is connected with the peculiarities of technological processes in the laboratory.
Air jets spouted through large-perforated surface mounted at the height of 2 m from the floor level, "flood" the lower control volume, entrained by natural convective currents from heat sources upward and removed from the upper area.
In order to take advantage of the proposed method of the required air exchange calculation, you must enter additional conditions, taking into account the provision of sanitary-hygienic characteristics of the current at the entrance of the service (work) area.
Exhaust air containing pollutants (combustion products), is expelled into the atmosphere by vertical jet discharge. Dividing ventilated rooms into two control volumes allows describing the research
process in a ventilated room more accurately and finding the air exchange in the
lab room during the tests on a more reasonable basis, allowing to provide safe
working conditions for the staff without the use of PPE.

In a flat solar collector SUN 1 The active development of environmental friendly energy sources alternative to HPPs is currently of great importance in the world. Such alternative energy sources are: water, ground, sun, wind, biofuel, etc. If we have a look at the atlas of solar energy resources on the territory of Russia, we can make a conclusion, that in many regions of our country solar activity level allows using solar collector. Though the analysis of different models of solar collector showed, that most of them are ineffective in the regions with cold climate, though the solar activity of these regions is of a great level. In this regard, a mathematical model of heat-mass exchange processes in flat solar collectors is introduced in this article. The model was a basis for the development of a new solar collector, named SUN 1, which has an original heating tubes form. This form allows heat transfer medium to be under the influence of solar energy for a longer time and consequently to warm to a higher temperature, increasing the warming rapidity.

The article describes the formation and implementation of virtual organizational structures for construction companies. We consider the components of virtual enterprises, the process of their integration and organization of system connections. Particular attention is paid to the method of forming the qualitative and quantitative elements of virtual structures.The introduction of virtual building production systems implies increased automation and the use of modern equipment in the offices of project participants and on construction sites, where the majority of technological operations is performed. Creating a virtual organizational structure requires a detailed study of all aspects of the future enterprise, no matter how long it will be functioning and what goals were set. Having determined the participants and the basic scheme of the virtual organizational structure, it is necessary put question of hardware and software.Obvious is the fact that the construction industry in our country is in need of highquality optimization and automation of the technological process components. Any innovation requires high-quality information base for successful implementation and operation in the given industry.

In the present time the necessity of quantitative evaluation of construction project efficiency is becoming increasingly current. It is connected with estimation of investment appeal of a project and with the necessity to estimate its organizational and technological level, and, as a consequence, providing the safety of a construction object. In the article the authors justify the necessity to form an instrument allowing to choose the optimal decision in the field of technologies and organization of construction works at arranging enveloping structures. The authors introduce and offer using organizational-technological potential of enveloping structures as a discrete indicator of the chosen organizational and technological solution. The future investigations will be aimed at database formation of organizational and technological potentials of completed projects. As a result the best values of the investigated potentials can be detached, that will lead to optimization of the terms and costs of the works during construction of multi-storeyed residential buildings.

This article is dedicated generalization of the approach to the formation of the integral potential of organizational and technological solutions. The scheme of decomposition of the main elements of a construction project is presented. Considered and described in detail the research algorithm and the formation of the integral potential of organizational and technological solutions and components as single integral potentials. It is proposed to divide the studies into following phases: selection of the unit capacity to be considered through the construction project decomposition into elementary components; carrying out expert studies to identify key parameters that influence the performance of a single building; development of a mathematical model based on regression dependence; the use of mathematical models to improve the performance of the integrated construction project potential. Components of the “elements - construction project” system are in line with the basic provisions of systems engineering, which are its subsystem. It was selected groups of professional experts with experience and knowledge in their respective fields. As a rule, they are managers and chief engineers of construction companies participating in the polls as experts. The formation of a mathematical model of a single integrated potential is based on the assumption that the probabilistic nature of addiction, but a tool for its construction will be a multifactor regression built on the basis of probabilistic and statistical methods. The examples of the practical use of the new tools such as an integrated potential of organizational and technological solutions are considered. Having numerical characteristics of individual integrated potentials, one can create indexes and algorithms to form the integrated potential of organizational and technological solutions of the construction project.

The physical reasons for building structures destruction are both the forces arising at stress-strain state of construction elements and external influences arising at emergency situations, as well as their moments, impulses and periodic impulses with the frequencies close to of fluctuations frequencies of construction elements. We shall call the mathematical calculation models for the parameters-reasons of destructions the basic models. The basic models of destruction of building structures elements allow not only providing necessary level of reliability and survivability of the elements and the construction as a whole already at the stage of their design, but also giving the chance, at their corresponding completion, to provide rational decisions on the general need of recovery works and their volume depending on destruction level. Especially important for rational design decisions development, which ensure the demanded constructional safety of building structures, is library creation of the basic mathematical models of standard processes of bearing elements destructions for standard construction designs for the purpose of the further forecast (assessment) of the level and probabilities of standard destructions. Some basic mathematical models of destructions processes of the standard elements of building structures are presented in the present article. A model of accounting for construction defects and a model of obtaining requirements to probabilities of partial destructions of a construction are given. Both of these models are probabilistic.

A mathematical model of an active system is considered in the article. An active system represents an organizational model. The authors research into the problem of inconsistency between the concerns of the management authority and those of the managed subject. The managed subject acts for its benefit and supplies realistic information to the management authority. The main method of research into the above systems is based on the mathematical simulation of administrative decision making procedures. The theoretical grounds represent the systems analysis, the game theory, the decisionmaking theory, operations research, discrete mathematics and the management theory. The active system theory is based on a coordinated mechanism of choice. If the coordinated mechanism of choice is unavailable, the mechanism closest to the coordinated one must be developed. In this case, the authors believe it appropriate to consider additional criteria characterizing the "proximity" of a decision to coordinated and cumulative criteria, which are equal to the sum of additional criteria adjusted by particular coefficients of importance. A set of plans that cannot be coordinated at the same time is composed on the basis of the analysis of additional criteria and the cumulative criterion. Model testing and mathematical simulation are presented in the article.

The problem of filtration in the conditions of suspended contact mass appears not only in the process of water purification, but also in other spheres of human activity.New theory on foreign particle motion inside suspended floc layer is observed (only their upward motion). The influence of horizontal limit of the suspended floc layer on foreign particle motion is considered. The co-authors present equations for calculating new space coordinates of a foreign particle.Therefore, the authors form mathematical model of the water purifying filter reactor functioning, which can be used in the process of studying the peculiarities of filtration and in prospect can be taken as the basis for experiment planning. Further specification of this model may be made in case of developing the method of calculating the free path length in space case.

The choice and use of rational routes at strict observance of deliveries terms help to achieve not only minimization of operational expenses, but also to reduce commodity and production stocks in warehouses by 1,5...2 times. Therefore special relevance is gained by the works allowing precisely calculating the volumes of a cargo transportation, to count the quantity of transport units necessary for providing cargo flow, to define the rational routes of transportation, and also to reduce total costs of transportation. On the basis of the analysis of the known mathematical methods applied in transport logistics, the authors drew a conclusion that the route of freight delivery is estimated according to the distance passed by the vehicle. However the time of freight delivery depends not only on distance, but also on a set of other factors, such as vehicle type, road capacity, intensity of transport stream, weather conditions, season and others. For taking note of additional factors when optimizing a freight delivery route the method of analogy and similarity is used by the authors. The transportation parameters were estimated by analogy with an electric chain. For this purpose the authors entered the new concepts “fictitious distance” and “conductivity of the road”. The mathematical model allowing optimizing the organization of freight delivery taking into account not only distances, but also the probable speed of the vehicle movement depending on the road quality, intensity of transport stream and weather conditions is developed. Further development of the system of decision-making support while choosing the optimum route of cargo delivery is planned.

This paper considers and asserts the need to obtain the results of inspection of a building at the stage of its commissioning in order to apply comprehensive methodology for assessing its residual life. The author proposes to build regression relationship by correlating the levels of the time series dynamics of stress at certain points of the object calculation scheme considering the results of subsequent surveys. It allows estimating the wear rate of structural elements. The assessment of the reliability and durability of the building frame in a deterministic form is based on the limit states method. The application of this method allows taking into account the random nature of not only the combination of existing loads, but also the strength properties of construction materials by creating a system of safety factors.

The modern transport system is a complex integrated object, which includes various road pavements, different technical means to provide vehicles motion, organizational systems of traffic management. In the contemporary conditions of construction industry functioning the task to create vehicle systems is of a great economic importance. Great labour and material resources are used for production of transport means for providing construction works and operation of these means. The authors consider the questions of theoretical and informational foundation development for the formation of the criteria basis of investment optimization task during construction of automatical and informational systems for increase of traffic safety in transport systems, providing zero accident rate.

Due to the influence of many different factors, the arrival of vehicles to technical inspection lines is stochastic. The existing methods of designing the network of technical inspection do not take full account of this fact, the consequence of which is the lack of inspection lines load at some periods of the year and its excess in the other. In the first case, we evidence the deteriorating of economic performance of these facilities, in the second - the quality of evaluating the technical condition of vehicles suffers. The authors proposed a method of justifying the minimum requirements of residential areas in the lines of technical examination, taking into account the probabilistic nature of vehicles inspection revenue. The use of the proposed method was shown on the example of a large village. Using the mathematical apparatus for calculation of queuing theory allows not only identifying the areas in need of inspection lines, but also, if necessary, providing technical and economic evaluation of the results obtained by calculations.

The current methods of predicting the demand of the community for the lines of technical inspection of vehicles do not fully take into account the probabilistic and statistical nature of the complaints of car owners. This results in significant mistakes in the determination of the number of such lines, accompanied by insufficient rhythm of their operation. The design errors related to the complexity of accurate account for calendar fluctuations of the number of appeals can be partially or completely eliminated by using mathematical apparatus of the queuing theory. In this case, the complex technical system is considered as an open multi-channel queuing system with limited queue length. The received flows and serviced requests are considered to be the simplest. From a practical point of view, the replacement of one type of computational model by the other allows ensuring a more sustainable mode of calculating operations using the computer. The paper also provides a calculation expression for defining the lower and upper confidence limits of the dispersion of the average values of the number of arrivals of vehicles at the technical inspection that allows setting the interval of uncertainty for searching the optimal solution.