In many applications of profiling cutting tool, define the envelope surface collection. Along with the classic approach to the definition of the envelope of the recently used and new. So, if your family schedule projected two-dimensional surfaces in space R4, then get some three dimensional hypersurface Σ. Kriminanta this is the envelope of family of surfaces. The authors study the surface Σ when setting its parametric equations and equation in implicit form held in the works.  Found some new properties of such surfaces. Due to the fact that when profiling cutting tool set family of surfaces, coordinate transformation equations, an important task is the study received thus hypersurface. On the basis of article studies obtained in a general manner the necessary payment according to calculate kriminanty and diskriminanty hypersurface.  They show examples of how to define envelopes two families of spheres. These are family formulas transform coordinates defining the translational and helical movement. The results are illustrated by computer polygonal models.  

Keywords: a family of surfaces, hypersurface, profiling, feature display, cutting tool

Discusses the problems of transition from open to closed systems of connection of consumers to the heat network. On the basis of fundamental analysis of the advantages and disadvantages of the various connection schemes of buildings comparison of energy efficiency and reliability of open and closed systems of a heat supply. Basic conditions guaranteeing the possibility of the device of the closed heating systems in buildings, присоединненных to thermal networks on the open circuit. Shows the need for reconstruction of water supply systems and power supply of the building when it transferred from open to closed scheme accession to the heat network.

Keywords: heat supply, district heating, closed heat supply scheme, open circuit heat supply, individual heating unit, reliability of heat supply, energy efficiency.

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.

The establishment of automated air monitoring systems is a promising way of the air monitoring devices development. The comparative analysis of literature has shown that thin films based on semiconductor metal oxides are effective and widely used material for air monitoring systems creation. In order to create effective and more sensitive sensors it is important to research processes that occur on the surface of the gas sensitive material when it contacts with different substances. The processes that proceed on the surface of gas sensitive material based on SiO2SnOxCuOy during the interaction with molecules of nitrogen dioxide. Quantum chemical calculations have shown that there are three possible mechanisms of interaction between the molecules of nitrogen dioxide with a surface of gas sensitive material.

Keywords: multitouch system of the monitoring, gas-sensitive material, molecules of dioxide of nitrogen

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.

  Results of researches of gas sensitive properties of zinc oxide films grown by reactive rf magnetron sputtering was shown. Process parameters, affected on the gas-sensitive ratio, response time, recovery time and the type of electrical conductivity of obtained films were identified. Optimal modes of magnetron sputtering of zinc oxide for implementing gas sensors (RF sputtering Zn target in a gas mixture of oxygen and argon at a concentration of 80% oxygen, a chamber pressure of 0.8 Pa and the magnetron power 100 W) were established. Avarage response time on NO2 gas was 5-15 sec.  The obtained values ​​of the gas-sensitivity were in the range 30-67% for NO2 concentrations from 20 to 100 ppm, CO and CO2 from 50 to 100 ppm and 81-97% for higher gas concentrations from 500 to 1000 ppm.  

Keywords: Nanotechnology, magnetron sputtering, zinc oxide, thin films, gas sensitivity

  In this work researches of structural and electrophysical properties of ferroelectric films of lead zirconate titanate (PZT) which afterwards is planned to apply in hybrid sensor systems are done. Values of capacities of the received samples are in the range from 200 to 1100 pF, the range of thickness of the received films is 300-1000 nanometers. X-ray analysis showed direct dependence of the quantitative maintenance of crystalline PZT in film structure from partial pressure of oxygen in the camera. By results of research the range of polarization of samples are in the range 0,06 – 2,2 µC/cm2, and values of calculated piezoelectric modules are in the range 0,04*10-12 – 13,3*10-12 C/N.

Keywords: sensors, segnetoelektric films, touch systems, piezoelectric modules.

The article investigates the impact on the normal stresses of inequality of the young modulus for tension and compression in the bending of reinforced beams. Obtained formulas for determination of the bending moments that arise in the fixture, compressed and stretched zone of the aggregate. Found the formula for the normal stresses arbitrarily supported reinforced beams, arbitrary cross section and arbitrarily loaded bending loads. For example, reinforced beams of rectangular cross-section shows the determination of the neutral line and maximum stresses.

Keywords: reinforced beam, elastic modulus, stress, normal concrete

Cracking of reinforced-concrete elements with holes is examined. Comparison of theoretical and experiment moments of crack’s  formation during torsion, and during intensive torsion with twist. Formula for practical calculations of cracking of reinforced-concrete elements with holes during torsion and formula for estimate of cracking of reinforced-concrete elements with holes during intensive torsion with twist is suggested.

Keywords: Crack, twist, torsion, reinforced-concrete, elements, hole, beam

  A principle of spectrometric systems of gas sensors was described. A model and a method of numerical modeling of spectrometric gas sensor with the combined radiator-receiver of infrared radiation on the basis of the punched semiconductor thermoresistor were proposed.

Keywords: spectrometric gas sensor, model, method of modeling

We propose a method for cooling the condenser compression refrigerator, including the use of melt water wetting the surface of the water condenser. The water is directed into the groove in the middle part of which is the tube condenser coil, and the water flows by gravity to the tribes of the inclined groove, wetting the surface of the trough and tube condenser. Remains of meltwater routed to the tank on the compressor.

Keywords: Household refrigerating appliances, water, cooling, condenser, reducing energy consumption

  In this article the mathematical model dynamic process installations for blast cleaning the surface, and clearly showed the graph of the transition process, given the theoretical integer parameters yield in the specific process conditions.

Keywords: Fluid Technology, a dynamic characteristic of the drive, nozzle - gate, jetting processing surface