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  • The methodology of full-scale testing of reinforced concrete beams as part of a ribbed monolithic floor

    In accordance with the requirements of Federal Law No. 384-FZ, the safety and reliability of buildings and structures must be ensured. One of the ways to confirm the safety and reliability of building structures is to conduct field tests. The authors of this article have developed a method for full-scale testing of a reinforced concrete beam with a span of 14.52 m as part of a monolithic reinforced concrete ribbed floor. The procedure for testing the beam was drawn up with the development of measures to ensure safety during work, the adjustment of the beam testing method by loading was performed, the beam was tested by loading method with fixation of its deflections, followed by analysis of the test results. The test results showed that the developed method can be used as a full-scale test to confirm the safety and reliability of building structures, namely horizontal reinforced concrete structures.

    Keywords: building structures, beam, destruction, safety, methodology, technical condition, field tests

  • General principles of risk assessment in the design of buildings and structures

    When solving the problem of ensuring the mechanical safety of buildings and structures according to GOST 27551-2014 “Reliability of building structures and foundations. Basic provisions” it is allowed to apply a risk-oriented approach. A mandatory stage of this approach is the forecast of the expected accident risk situation of the facility. Due to the fact that the current regulatory documents on risks do not reflect all the features of the stress-strain state of building structures and foundations of buildings and structures during the operation of structures and, therefore, do not allow for a sufficiently accurate assessment of the safety of structural systems, risk assessment for building structures is a very relevant scientific and technical problem.

    Keywords: building, building structures, design, destruction, safety, accident risk, risk assessment, risk management, monitoring and risk analysis

  • Analysis of the development of housing construction in the last decade in the Russian Federation

    The article highlights the main factors that determine the direction of development of housing construction and housing policy. Data on programs to support individuals and legal entities for the development of housing construction are given. The data on the commissioning of residential buildings in the Russian Federation, depending on the type of area, are presented. The analysis and assessment of the growth rate of commissioning of residential buildings was carried out and the factors contributing to their increase were identified.

    Keywords: residential construction, real estate, affordable housing, citizen support, growth rate, housing policy, construction industry, standard of living, housing

  • The mobility of the concrete mixture as the main factor in the quality of monolithic thickly reinforced column structures

    The article is devoted to the selection of the mobility of the concrete mixture for monolithic densely reinforced reinforced concrete columns directly on the construction site. The main defects in pouring concrete mixtures are described, the causes of their occurrence are analyzed. Empirically, the mobility of the concrete mixture, the technology of laying and the organization of work during the concreting of structures of heavily reinforced columns were selected. Recommendations are given for eliminating defects in monolithic reinforced concrete columns.

    Keywords: column, densely reinforced structure, monolithic structure, concrete mix, cone slump, plasticity of concrete, workability, composition selection, monolithic defects

  • Pt/SnOx-C electrocatalytic systems with different morphology of tin oxide

    Electrocatalytic systems based on platinum and tin oxides with different composition and microstructure characteristics were prepared via sequential electrochemical dispersion of tin and platinum electrodes under the action of an alternating pulsed current. The complex of physicochemical methods investigated the effect of electrolyte on the composition and structure obtained in the first stage of the synthesis of tin oxides.It is shown that the presence of tin oxide in a Pt-containing catalytic system generally has a promoting effect on the oxidation of ethanol on platinum. However, neither the composition nor the microstructure of the oxide affects the electrocatalytic properties of the Pt-containing catalyst.

    Keywords: Pt/C, tin oxide, tin dioxide, ethanol, platinum nanoparticles, electrocatalysis, alternating current, metals electrooxidation, electrochemical dispersion, fuel cell

  • Morphology and properties of nano ZnO obtained using pulse alternating current

    In this paper the method of electrochemical oxidation/dispersion of zinc using pulse alternating current with average density of 0.2:1.2 A/cm2 was used. The mixture of ZnO and Zn5(OH)8Cl2·H2O (simonkolleite) was obtained. The application of this product as a photocatalyst provides a practically full removal of methylene blue dye under UV light. When the sample is calcined at 400 °С the decomposition of simonkolleite with a ZnO formation occurs. It is accompanied by decrease in surface area and photocatalytic activity of the material.

    Keywords: zinc oxide, nanoparticle, simonkolleite, pulse alternating current, morphology, photocatalysis, methylene blue

  • Mediator-assisted selective oxidation of 5-hydroxymethylfurfural to 2.5-diformylfuran in the presence of collidine

    The process of 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxyl/I2 mediated oxidation of 5-hydroxylmethylfurfural in a twophase system consisting of a methylene chloride and aqueous solution containing sodium hydrogen carbonate was investigated. It was shown that the introduction into the reaction system collidine provides selective oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran (yield 99% at a selectivity of 100%).The optimal composition of the system and the optimal conditions of synthesis were determined. A mechanism of promoting the oxidation of the OH- group of 5-hydroxymethylfurfural and protecting the further oxidation of 2,5-diformylfuran by collidine was proposed.

    Keywords: 5-hydroxymethylfurfural, 2,5-diformylfuran, nitroxyl radical, collidine

  • Optimizing the number and range of the PWG in view stable operation of the gas pressure regulator

    In modern conditions developed and used hydraulic calculation of gas networks program. With them, you can get the pressure value at the nodes of the distribution system of gas supply, costs, and gas velocity in the settlement areas. But do not count in these economic aspects, ie, It is not determined the most economical option, which can be obtained by optimizing the individual characteristics of the gas network. These characteristics in the development of the concept of gas supply is a rational distribution points gas reduction and determination of optimal kolichestva.Priveden calculation of the optimal number of the PWG and the optimal diameter of individual sections of the network of medium pressure gas pipelines to ensure the best economic performance timing system. Defined pressure regulator bandwidth capacity for its stable operation. To determine the effect an increase in the inlet pressure on the diameter of the pipeline.

    Keywords: optimum range, the optimum load, optimization of pressure, the diameter of the gas-supply circuit, the hydraulic calculation capacity pressure regulator.

  • The determination of integrability order of economic time series

    The article presents the results of the analysis of the fluctuations of the USD/RUB and the definitions of integrability of the corresponding time series. The research of currency pair by linear methods revealed the presence of non-stationarity in the behavior of the time series, as a result we came to the conclusion that it is impossible to create a high-quality predictive model based on parametric methods.An attempt was made to improve the quality of the forecast to study the integrability of the time series. For this purpose we used various modifications of test the Dickey–Fuller and software products. We tested estimate the order of integrability of two economic time series ,characterizing fluctuations of the U.S. dollar against the ruble and the dynamics of the stock of the Sberbank. The results of the analysis prove that the Dickey-Fuller test is a simple and reliable way to assess the order of integrability of the time series. The benefits of the ADF-test before DF-test are identified.The result is a stationary model of time series , which we can used for forecasting.

    Keywords: time series, the main hypothesis, alternative hypothesis, Student criterion, stationarity, nonstationarity, integrability,the test for unit root, the Dickey-Fuller test

  • Influence of the carbon suppot type on the process of electrochemical oxidation of carbon monooxide on Pt/C catalyst

    The process of electrochemical oxidation of carbon monooxide on Pt/C catalytsts with different structure of carbon support was studied. Pt/C catalysts were prepared via electrochemical dispersion of platinum electrodes under the action of an alternating pulse current. It was shown that the structure of the carbon support has a significant impact on the degree of agglomeration of platinum nanoparticles and, consequently, on the value of the specific surface area of the catalyst, but does not affect the degree of filling of platinum by carbon monoxide.

    Keywords: fuel cell, electrocatalysis, electrochemical dispersion, Pt/C catalyst, carbon monoxide, CO electrochemical oxidation

  • Wear resistance of the carbon electrical material by modifying novolac binder

    Prospects for manufacturing electrical investigated products based on modified copper oxide (I) a novolac resin. It is shown that copper oxide modification improves the physico-mechanical, tribological, electrical properties, resistance to mechanical wear and oxidation products of the materials. Introduction of coke in the material increases its durability when operating on the worn contact network. Trial runs have shown a trolley parks that the contact insertion trolley manufactured using a modified copper oxide (I) novolak binder in performance on average 2-4 times higher than the commercial materials of different manufacturers

    Keywords: trolley collector insert, carbon and graphite material, modification of the novolak binder, copper oxide (I), sea trials

  • Joint-stock insurance business on the Don in the second half of XIX - early XX centuries

    History share of insurance business in the Province of the Don, the characteristic four stages of development process, the analysis in general and the specific activity of sixteen joint campaigns, including foreign, on the Don in the late XIX - early XX centuries. ("New York", "Urbain", "Ekvitebl"). The social composition of the policyholders, insurance forms discounts logic of competition  

    Keywords: insurance organization of insurance business corporate insurance insured event insurance discount insurance premium insurance rates insurance capital

  • Determination of the atomic structure of bimetallic Pt-Ag nanoparticles in metal-carbon catalysts by X-ray absorption spectroscopy data

    The atomic structure of bimetallic nanoparticles of Pt-Ag composition, which are the part of metal-carbon electro-catalysts PtAg/C, is studied by means of EXAFS spectroscopy using the suggested technique. These materials have been prepared by methods of consistent and simultaneous deposition of Ag and Pt atoms from aqueous ethylene glycol solutions of their salts with subsequent acid treatment. The values ​​of the structural parameters of the near environment of platinum atoms are determined. The nature of the distribution of components in nanoparticles is established. Cluster models of nanoparticles are constructed. The fraction of Pt atoms in the working shell and its dependance on preparation methods in each case are determined.

    Keywords: Metal-carbon electrocatalysts, bimetallic nanoparticles, Catalysis, Platinum, X-ray absorption spectroscopy, atomic structure

  • Study of corrosion and electrochemical properties of anode coatings oxide for production dilute sodium hypochlorite

    Consider the choice of coating anodes for electrolysis of sodium hypochlorite nizkokontsentrovannogo 3% solution of sodium salt of food and water of the Black Sea. Defined corrosion resistance of anodes with different laying oxides of ruthenium and iridium and their characteristics: yield chlorine-current voltage on the cell growth dynamics of the concentration of active chlorine in the solution.

    Keywords: oxide coatings, iridium, ruthenium, low concentration of sodium hypochlorite, the corrosion resistance of anodes according to the output current of chlorine, the electrolysis of a 3% solution of sodium edible salt and sea water.

  • Local Atomic and Electronic Structure of the Fe dopants in AlN:Fe Nanorods

    Fe-doped AlN nanorods were studied by means of x-ray absorption spectroscopy above the Fe K- and L2,3- edges. Theoretical simulations of the x-ray absorption spectra show that Fe atoms mainly substitute Al. A minor fraction of Fe interstitials or Fe-Al-N ternary alloy can be identified as well. Bader’s AIM analysis predicts that neutral substitutional FeAl defect is in 2+ charge state, though Al in pure AlN is in 3+ charge state.  Fe L2,3 absorption spectra and photoluminescence data indicate the coexistence of Fe2+/Fe3+ in AlN:Fe nanorods so different charge states of substitutional FeAl should co-exist.

    Keywords: diversification of management, production diversification, financial and economic purposes of a diversification, technological purposes of ensuring flexibility of production