For the statically indeterminate systems under consideration, there is an optimal ratio between the load-bearing capacity of stretched and out-of-center compressed elements, in which the required reliability will be provided at the lowest value of the mathematical expectation of an external destructive load. It should also be noted that for statically indeterminate systems, the beginning of rebar fluidity is not a sign of destruction, but only indicates the beginning of an intensive redistribution of forces in it. Therefore, the values of C, do not refer to the beginning of the rebar flow, but to the complete exhaustion of the load-bearing capacity. The reliability of statically undetectable systems, including prestressed trusses, is always higher, all other things being equal, than that of statically definable systems.

Keywords: reinforced concrete, reinforced concrete structures, statically indeterminate systems, reliability

The article provides a study and calculation of the dependence of the hazardous area resulting from the operation of the flare equipment on the height of the flare at which service equipment and personnel can operate

Keywords: flare unit, radiation intensity, safe operation zone, thermal voltage

The construction of social infrastructure is an integral part of improving the quality of life. The study systematized the main problems faced by the developer and the state in the construction of social infrastructure, provides an approximate list of measures that can improve the situation.

Keywords: social infrastructure, state, developer, economy, residential complex, public-private sector, housing construction, state, operation

This article discusses the methodology for calculating buildings and structures for the maximum design earthquake using the Dynamics module + LIRA-SAPR 2019 software package, using accelerograms, collects and converts static loads into dynamic ones, and also calculates an industrial building for the situation of maximum design earthquake with subsequent analysis

Keywords: maximum calculated earthquake, calculation, seismic impact, loads, accelerogram

Article is devoted to acquaintance with methods which are used in the work by experts-builders when conducting construction technical expertizes of building constructions, buildings and a construction. The list of the main methods used in researches by the expert is provided and also each method is considered in more detail.

Keywords: Method, examination, expert, technique, fundamental principle, special case, graphic model, construction designs, construction technical expertize

An experimental device designed for the detection of peripheral veins during the injection and infusion was developed on the basis of recording the difference in the intensity of the optical signal reflected from the vessels and surrounding tissues. The device allows to perform the detection of the locations of vessels, to determine their projection, to confidently distinguish veins and arteries. The effectiveness of the application is shown in tests on healthy people and patients with diabetic angiopathy. The device is very compact, has a simple design and low cost.

Keywords: infrared light, optical pair, photodiode, LED, introscopy, vascular detection, complicated intravenous access, peripheral vein, photoplethysmography, angiopathy

In the article results of approbation of the experimental devices designed for visualization of blood vessels developed by the authors are presented. Experimental device number one is an emitter of infrared light, the experimental device number two is a emitter of visible red light. Devices can be recommended for use in patients with no factors impeding vascular imaging and in patients with elevated body mass index.

Keywords: infrared radiation, optical pair, photodiode, LED, introscopy, visible red light, vascular detection, complicated intravenous access, peripheral vein

The article gives judgments, focuses on the need for the development of military and town-planning sciences, based on the reality of practice, which, apart from armament, must take into account the urban and architectural components formed as a special kind of weapon of future wars.

Keywords: Urban planning, Armed forces, military science, architecture, defense infrastructure, housing

The deals with the topical issues of legal regulation of entrepreneurial activity in Russia. Traced the General trends, various variants and development of entrepreneurship in historical perspective.

Keywords: Economics of industry, enterprise, legal regulation of predprenimatelstva, history of entrepreneurship

In this work we have investigated the structure of individual single-walled and multi-walled carbon nanotubes by high-resolution electron microscopy and electron diffraction. To grow carbon nanotubes we used a catalytic chemical vapor deposition method. It was shown, that this synthesis protocol gave in general single-walled and double-walled carbon nanotubes with a high level of crystallinity. The diameters of the nanotubes were in the range 1.5 - 7 nm. We also observed that there was a certain level of amorphous carbon deposited on the nanotube surface during the growth. In this work we also present the structure analysis of the double-walled carbon nanotube by means of electron diffraction. We show that the structural date derived from electron microscopy and electron diffraction agree within the experimental error.

Keywords: Carbon nanotubes, electron diffraction, electron microscopy

The simulation of two-dimensional spherical crystals consisting of a large number of particles is carried out. These shells were analyzed based on their geometric structure and energy distribution. Various types of defects formed in a state of equilibrium  is considered. Being shown the ambiguity of the existing method of their interpretation. A new way of describing such defects in the close-packed two-dimensional crystals with different topology is suggested.  

Keywords: topological defects, two-dimensional materials, spherical crystals, topological charge

  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

  We have investigated electrical and gas sensitive properties of gas sensor based on carbon nanotubes (CNT) and carbon nanotubes modified by metal oxides (such as tin oxide and silicon oxide).  Also we  have find out that modification of  CNT by  metal oxides helps to  improve film`s adhesion to substrate, decrease electrical resistance, recovery time, working temperature , enhance gas sensitivity in comparison with sensitive elements based  only on CNT or metal oxides. Moreover experimental results showed that properties of composite material depend on concentration correlation of solutions. As a result we can get highest sensitivity of sensor element by choosing optimal relation between concentrations of solutions.

Keywords: Сarbon nanotubes, modification, tin oxide, silicon oxide, gas sensor

`

Keywords: