A significant part of Rostov region and North Caucasus regions of the built-over territories according to its settlement consists of I and II type loess soil.
The author develops a method for optimal parameters determination of the stabilized loess bases under the influence of different factors (loads, emergency steeping, ground waters level alteration etc.). Selection of optimality criteria depends on the applicable method of technical melioration. Determinative limitation is the calculation upon the II group of limit states. Application of non-linear mechanical and mathematical models for calculation of structural and unstable soils upon deformations is recommended.
Silicification stabilizing of loess soils is almost impossible at the filtration coefficient of K<0.1 m/day.
Characteristics of the fixed massive depend on soil moisture level, injection mode, density of sodium silicate solution, time of injection and volume of solution.
Determinative conditions for the possibility of soils injection stabilizing with cement or other solutions are the following: geometric criterion (cement particles size and soil pores size, determined by the active openness), solution viscosity in relation to density, injection pressure, water-cement ratio, filtration coefficient. The most common pores in loess soils are active pores of 20 micron diameter, quantity of which comprises 20-50% of total soil openness. Solution-conductive (active openness) are the pores of more than 0.01 mm at size.
Selection of stabilizing method depends on the form of the stabilized area.
The author, basing on variation principles of mechanics of constructive and non-linear systems and theory of adaptive evolution of mechanical systems, developed determination method of rational form of the stabilized basal complex. Specific feature of the developed model is increasing of bearing capacity, stability and location of stabilizing area with more specific accuracy level within soil. To detect stress-deformed state in bases of buildings and constructions there are elaborated programs in APDL languages in the ANSYS software environment.
Keywords: loess soil; method for optimal parameters determimation; form of the stabilized area;theory of adaptive evolution of mechanical systems; ANSYS software environment
In the implementation of dynamic re-routing of traffic it is important to notice that the threshold depends on the network layout and type of the roads. Full paper includes appropriate relationships, figures and analysis of simulation results to define the re-routing rate of dynamic traffic reroutig
Keywords: re-routing, rate, dynamic traffic assignment, traffic conditions
This article is devoted to the analytical determination of deflections of beams with corrugated web. The reduced shear modulus which must be considered when determining the components deflection from of the shear strain in the beam with corrugated web is defined. Applying the energy method in the form of the Ritz, the problem of determining deflections with considering of bending strain and shear strain is solved. This article, as an example, is considered simply supported beam on both sides of constant and variable cross-section and are given to the final formulas according with three kinds of loading. The results of the calculation of the numerical examples for the three main shapes of corrugated web are submitted. Numerical results with great accuracy are consistent with calculations based on the finite element method.
Keywords: beams, corrugated web, energy, work, deflection, shear strain
Consider the use of management system of heating and ventilation plants in greenhouses, uniform distribution of heat and humidity in the area of biological objects, the use of an improved system of management regimes of the microclimate in the protected ground on the basis of programmable smart relays
Keywords: power consumption, temperature-humidity conditions, microclimate
Consensus problem involves a system of processes, some of which may be faulty. A fundamental problem of fault-tolerant distributed computing is for the reliable processes to reach a agreement on a same decision. One approach to achieving such agreement is for processes to vote and agree on the majority value. In the absence of faults, this works fine, but the vote even one faulty process can swing the outcome. In this paper we present some result of analysis of a mixed-failure model, where t processes may fail, b out of which is the Byzantine failures and remaining c is crash processes. In a asynchronous model of computation for several distributed problems it turns out that a collection of N processes can tolerate c crash failures if 2c < N, while robustness against b Byzantine failures requires 3b < N. Our algorithm rely on a weak definition of the Byzantine failures which disallows them act as a dead or a crash processes and can tolerate the 2(N – 2c)/3 failures.
Keywords: fault tolerance, distributed algorithms, asynchronous networks, byzantine failures
The results of the heat transfer processes studies in the heat exchange borehole (BHE), equipped with coaxial collector in order to establish the influence of its design parameters, the properties of the rock mass, mode and duration of the coolant flow to the effective temperature difference. The resulting analytical equation for the effective temperature difference in the conditions of unsteady heat transfer experimentally verified in a lab BHE and can be used in the design of these BHE systems in specific geological and technical conditions. Use the resulting equation for the inverse calculation can be counted the diameter and the depth of the BHE, as well as the duration of the coolant circulation in the coaxial collector. The advantage of such approach is the consideration of the main factors that influence the of the effective temperature difference.
Keywords: borehole heat exchanger (BHE), effective temperature difference, coaxial collector, heat pump, low-potential energy
Laboratory technology was developed to fabricate flexible piezocomposites with ferroelectric phase - polymers having signal reception factorv • gv 5000 • 10-15 m2 / N. The values of the given coefficient were achieved by switching from a probabilistic (spontaneous) percolation to a correlated one in the process of forming material. This made the production of 0-1–3 piezocomposites, in which a part of piezophase has 0 connectivity, and the other part – 1 connectivity possible. To improve the efficiency of piezocomposite polarization before their manufacturing the surface of piezophase particles, which were obtained by the partial destruction of the porous frameworks, was treated with coupling agent, which did not only improve the polymer adhesion to piezophase, but also allowed the removal of water from the particle surface. The latter effect reduced the value of interfacial conductivity, i.e. prevented the voltage drop of the polarizing field. Matching of polymer conductivity and piezoceramic particles by determining the optimal polarization temperature was carried out as well.
Keywords: piezocomposites, percolation, connectivity, electrophysical properties
Credit availability to construction sector entities determines for thin-capitalized construction firms the possibility of survival during the crisis and of efficient growth during the economic recovery. The main lenders for construction sector entities are commercial creditors (suppliers) and banks. Although their credit policies are similar, debt to commercial creditors dominate in the balance sheets of borrowers, because of customary business practices in construction industry and regulatory distinctions.
Keywords: information asymmetry, agency theory, trade credit
This paper presents key capital structure determinants of construction companies and their impact on fund raising and financing mix formation in accordance with the conditions of construction activity. It was found that profitability and tangibility have a positive effect on leverage, risk - the negative and the effect of company size, assets growth rate and taxes is ambiguous.
Keywords: capital structure determinants, profitability, risk, taxes, tangibility, construction companies
The article describes the main problems of circuit simulation. The problem of solving ill-conditioned systems of linear algebraic equations (SLAE) of large dimension. The modified algorithm is a linear algebraic solutions. Described a hybrid evolutionary algorithm for solving linear systems based on the proposed modified method. The results of the pilot study and comparison of the algorithm with the algorithms based on the traditional methods for solving linear algebraic equation, which confirm the advantages of the hybrid evolutionary algorithm.
Keywords: Genetic operators, evolutionary algorithm, the system of linear algebraic equations, computer-aided design.
This paper is devoted to development of gas sensors air control. It is shown that copper oxides are the promising materials for high sensitive sensors. The CuOx film material was syntheses by means of citrate sol-gel technique. The sensors fabricated on the basis of CuOx film material were sensitive to ammonia gas in the range of 25-150 ppm. Working temperature was determined as 180 °C. Such sensors can be used for work area air control of industrial enterprises.
Keywords: gas-sensitive element, atmospheric air, sensors, copper oxides
The mathematical model of the potential distribution in the semiconductor surficial region in the presence of deep-lying levels in its forbidden zone which specified by multiple-charge impurity centers has been developed. The simulation results can be used for the width of the space charge region estimation, for the prognostication of the most probable mechanism of the charge carriers transfer in metal-semiconductor structure with multiple-charge deep-lying levels and also for the prognostication of the barrier capacitance value. It can be used in the development of solid-state electronic devices with improved values of some parameters.
Keywords: Poisson’s equation, multiple-charge impurity center, potential distribution, deep-lying levels
Stability of sensors on the basis of inorganic oxide materials is one of the primary goals by working out of atmospheric air control devices. In this work long-term stability of a sensor response on the basis of the SiO2SnOxCuOy material to carbon oxide (II) exposure in a range of concentration 1-100 ppm is studied. It is shown that the sensor response differs high stability and reproducibility. Continuous heating within 21 days to working temperature (350°С) influence its value negligibly.
Keywords: stability of a response, sensor, carbon oxide, material of structure of SiO2SnOxCuOy.
The express-method of estimate of the rate of wetting of pulverulent powder of KCl is developed. The wettability of potassium chloride powder containing the admixtures of flotoreagents by solutions of different binders is studied.
Keywords: wettability, flotoreagent, binder, transformation, muriatic amine, sodium metasilicate
Technology of fabricating unheated gas sensors based on polyacrylonitrile (PAN) using different temperature and time modes of a two stages IR-pyrolyze is developed for the remote control of the human condition. Gas-sensing elements based on PAN films and cobalt- and copper-containing PAN films are fabricated. Gas sensitive characteristics of the gained samples to CO, Cl2 and CHCl3 in atmospheric conditions are determined. We have found that gas-sensitivity of the samples depends on the composition of the original film-forming solution and on the process parameters of fabricating the film material. Moreover the samples show sensitivity and selectivity at room temperature. The benefits of this study is that films based on PAN and metal-PAN are the most promising material for electronic engineering including gas sensors for the remote monitoring of the human condition.
Keywords: Nanocomposite materials, gas-sensing layer, metal-containing organic polymers, IR- pyrolyze