This article presents the results of studies on the possible use of hoisting-and-transport rope complexes in the aftermath of emergency and environmental situations. The advantages of using self-propelled transport and freight carriages based on soft pneumatic bearings for rescue operations are considered. An algorithm is described for a software package designed to automate the process control of a freight-carriage used to lift and move cargo at predetermined coordinates. To implement the functioning of the software package, a processing technique was used for incoming and outgoing data, input and output streams, data collection centers using Java TCP / IP technology. An example of a graphical interface of the software.
Keywords: software package, control automation, hoisting and transport mechanism, protocol, JAVA, algorithm, environmental consequences, cable system, local coordinates
GOST 10060-2012 as the main criterion of frost resistance for all concretes, including fine-grained, established the ratio of the compressive strength of the main and control samples is not less than 0.9, taking into account the coefficient of variation of strength in the series. There are numerous studies in which the dependence of the frost resistance of concrete on the nature of its porosity is revealed, and the criteria of frost resistance in the form of, for example, the ratio of open and conditionally closed porosity are proposed. The article examines the impact of indicators of porosity on frost resistance of mortar (fine aggregate concrete), the basic criterion GOST 10060-2012, and also for frost resistance of the contact zone according to GOST 31357 - one of the normalized indicators of quality of solutions and fine-grained concrete obtained from dry mixes. The purpose of this study is to identify the dependence of changes in the compression and bending strengths, as well as changes in adhesion to the base of polymer-modified fine-grained concrete on the nature of porosity. The frost resistance of 36 compositions obtained using three different Portland cements and three redispersible polymer powders with a dosage from 0 to 3% by weight of the dry mixture was studied. In addition to polymers, low-modulus inclusions in the form of ash microsphere or entrained air are introduced into a number of compositions. The main samples were tested after 75 freeze-thaw cycles according to GOST 31357.
Keywords: dry mixes, frost resistance of the contact zone, open porosity, adhesion to the base
Results of modeling and a pilot study of a low-pass filter with a cut-off frequency of 4 GHz are given. Modeling of the filter was carried out in MicrowaveOffice application program package. The experiment was made on the vector analyzer of RXA chains. Results of modeling and an experiment conform to the imposed requirements, namely: - cut-off frequency is 4 GHz; - losses in bandwidth no more than 3 dB; - an obstacle on the second harmonic of cut-off frequency not less than 60 dB; - wave resistance of an input and exit of 50 Ohms.
Keywords: low-pass filter; cut-off frequency; losses in bandwidth; losses in an obstacle band; modeling; experiment
he article is devoted to the question of selection of aerodynamic parameters of drying in the apparatus of the filtered-fluidized bed of dispersed particles – carbon-black containing wastes materials and granules of sodium salts in solution of modeling problems. The design of the studied gas pressure distribution grid fluidized bed of dispersed materials of the tray kind provides the possibility to efficiently fulfill the drying process at relatively low speeds of the drying agent. It is allowed to reduce the removal of particles of material from the bed and its exhaust into the atmosphere. The average flow rate of gas motion and the number of fluidization for the main stages of the filtered-fluidized bed of the studied materials and aerodynamic parameters (drop pressure losses) are determined. It was found the fluidization number in the range 1.25-1.5 and the bed height was about 0.25 m. The total aerodynamic drop pressure losses of the dispersed materials’ bed and had acceptable meanings within range from 90 to 130 kg / m2. For the recommended range the coefficient was equal 30-45. Data were obtained on the phases of fluidization, the values of the aerodynamic parameters of drying, and the areas of operating conditions that provide a fairly uniform circulation of the material in the layer and reliable operation of the apparatus.
Keywords: modeling, drying, waste, dispersed material, fluidization, bed, velocity, aerodynamics, pollution, atmosphere
Within the framework of the kinematic model, calculation formulas are obtained for determining the deformation of a water-saturated base from weak soils, taking into account vertical reinforcement and the bearing capacity of pore water. Theoretically justified the use of vertical reinforcement, aimed at strengthening the bearing capacity of the soil base.
Keywords: weak soil, water-saturated base of the road, deformation, vertical reinforcement
Based on the use of additional boundary conditions (characteristics) and the integral method of heat balance, a numerical and analytical solution of the heat conduction problem for an infinitely extended plate is obtained under symmetric boundary conditions of the third kind with constant internal heat sources in time. Considering the heat flux on the plate surface as a new sought function, a simple analytical form of the specified problem is obtained. Using the proposed approach is possible for solving partial differential equations that do not allow separation of variables.
Keywords: analytical solution, internal heat sources, non-stationary thermal conductivity, boundary value problem, boundary conditions of the third kind, additional function, integral of heat balance
The paving slab market analysis and development prospects for the Rostov Region are given in this article. The market prospects are considered from the point of view of paving slab manufacturers on their participation in government programs of a modern urban environment formation and improvement. The main changes in the product specifications requirements are considered taking into account the enactment of GOST 17608-2017 instead of GOST 17608-91. We analysed the pricing policy of large manufacturers of paving slabs operating in the Rostov Region. Then we also considered the prospects of paving slab sales for municipal projects and in the private segment. We also reviewed the government programs for creation of a comfortable urban environment and their financing in the Rostov Region, as well as cooperation prospects between the municipal government and business in terms of concession agreements. Finally, we defined the main consumer categories for the paving slabs and the consumption structure of the paving slabs market.
Keywords: paving flag, paving slabs, improvement, modern urban environment, the formation of a modern urban environment, paving
The simulation of a multilayer structure in the finite element Ansys complex is considered. The design consists of 10 layers, each of which has certain specific properties. The model is an imitation of the soil base pavement. We consider the simulation in the form of a simplified, flat statement of the problem. The analysis of the oscillations under impact. The wave field of displacements at a given part of the structure is analyzed. Based on a numerical experiment, an approach to estimating the characteristics of a layer is constructed.
Keywords: multi-layer construction, vibration diagnostics, simulation, FEM, Ansys, pulse action, dynamics, fluctuations
This article describes the method of dust emission suppression at a construction site. The results of the effectiveness of the developed equipment, fog formation gun, were obtained in the course of full-scale measurements in the course of stone installation works at the construction site in Rostov-on-don. The assessment of the air dustiness of the builder workplace and the degree of impact of the fog formation gun were attended with the statistical dependence of the number of dust particles PM2.5-PM10 . During the analysis, the following factors were studied: the location of the workplace at the construction site, the relative humidity and temperature. During the study, the following conditions were met: the premises were closed; the study was carried out in the process of performing stone installation works. The results of the experiment showed the effectiveness of the fog gun.
Keywords: environmental safety, fine dust, dust settling, dust suppression, ecology in construction, dust collectors, construction work, air protection, labor protection in construction, dust pollution
For a numerical study of the stress-strain state of the edge sections of a coal vein under the influence of a mining zone, there is a mathematical model of the geomass deformation processes, which is reproduced in the form of boundary value problems of the theory of elasticity. The problem was solved by the finite element method in a variational formulation, in which the functional was minimized with full potential energy to determine displacements in narrow of elements. Computational experiments were carried out using the author's complex of programs. Based on the results of numerical modeling, recommendations for strengthening the coal target and definitely bearing capacity was developed. The use of the developed mathematical model and software package allows us to design documents at the development stage, to predict the stress-strain state of the geomass in the zone of influence of the underground mining system.
Keywords: Mathematical model, numerical modeling, computational experiment, software package
The article reveals the essence and significance of the socio-cultural phenomenon-architectural competition. Features of its application in modern industrial architecture of Europe. Significant advantages of this type of project activity in the context of the specifics of the architecture of industrial enterprises are revealed.
Keywords: Architectural competition, creative competition, industrial architecture, modern architecture, environmental friendliness, energy efficiency, landscape environment, architecture of Europe
The article presents the results of testing samples of welded joints of polyethylene pipes for crack resistance at various temperatures. It is shown that in the weld zone a decrease in the stress intensity factor is observed up to 27% compared with the base material.
Keywords: Polymer, polyethylene, pipe, stretching, crack resistance, low temperatures, brittle failure, crack, welding, welded joint, fusion zone
In this article the comparative analysis of reinforcement of monolithic reinforced concrete plate under various conditions of calculation is made: without seismic actions, with design earthquake and with maximum design earthquake. It was found that taking into account the seismicity of 9 points without the use of methods of active seismic protection leads to an increase reinforcement to 28 % when taking into account the design earthquake and 81 % when calculating the maximum design earthquake. In addition, the analysis of the tool "Consumption of concrete and reinforcement" in the Lira-SAPR is made. The correction factor for the transition from theoretical to real reinforcement was obtained: it ranged from 2.4 to 3.0
Keywords: seismic impact, Lira-SAPR, maximum design earthquake calculation, frame calculation, slab, reinforced concrete, specific consumption of reinforcement
Durability of concrete, including fine-grained, with alternating cyclic temperature effect of the external environment is normalized according to GOST 26633 mark on frost resistance, and frost resistance criterion for all concrete in accordance with GOST 10060-2012 is the ratio of ultimate strength on compression of the main and control samples not less than 0.9 with a coefficient of variation of strength in the series, while for concrete road and airfield pavements is another additional criterion is the loss of mass. In the previous edition of GOST 10060, the ratio of the compressive strength of the main and control samples not less than 0.95 was adopted as the criterion of frost resistance for all concretes. GOST 31357 normalizes the indicator "frost resistance of the contact zone" for a number of mortars or fine-grained concretes obtained from dry building mixtures. This indicator characterizes the ability of the solution or fine-grained concrete to maintain the strength of adhesion to the concrete base after a certain number of freeze-thaw cycles. For the brand for frost resistance of the contact zone from Fkz25 to Fkz100, the number of cycles is taken, after which the decrease in the adhesion strength to the base does not exceed 20% according to GOST 31356, and in this case the coefficient of variation of the clutch values measured in the series is not taken into account. Due to the limited information on the change in the in-series coefficient of variation of strength after cyclic freezing-thawing, as well as the ratio of frost resistance by the criterion of compressive strength and adhesion strength to the base, the purpose of this study was to identify patterns of change in the in-series coefficient of variation of strength and adhesion strength to the base of fine-grained concretes obtained from dry building mixtures based on various Portland cements with the content of various redispersible polymer powders from 0 to 3%. The studies were carried out on the basis of 75 freeze-thaw cycles. This paper presents the results on the change in the coefficient of variation of strength after cyclic freezing-thawing and the ratio of frost resistance coefficients
Keywords: frost resistance of concrete, coefficient of variation of strength, coefficient of frost resistance, fine-grained concrete, dry mixes
The modeling of a hollow core slab in the finite element complex Ansys is considered. The construction of a 3D model is considered. Numerical modeling was carried out under static loading of the floor slab. The influence of material properties on the parameters of the stress state and deflection of the structure is investigated. Based on a numerical experiment, an approach to assessing the characteristics of a structure is constructed.
Keywords: hollow core slab, static analysis, modeling, FEM, Ansys, stress state, deflection