After testing according to the developed state methods and procedures for polyurethane foam thermal insulation of laminated composite structures with metal facings, the issues of correlation, ...probabilistic-statistical regression models between the signs of elasticity in tension Eshear and signs of elasticity in shear Gshear were investigated. It is shown that the test results are random stochastic values. Their variability, depending on the type of tests and the parameter under study, is in the acceptable average values. The presence of a significant number of each of the characteristics, for example, Eshear - Gshift, predetermined the use of correlation tables to establish the fact of a relationship. Modules of elasticity under tension and shear were determined. The correlation coefficient between Eshear and Gshift is 0.659. With the help of a computer program, correlation tables were built and the calculation of the probabilistic-statistical interaction of characteristics with different reference points was made. When considering one-dimensional aggregates, the laws of distribution of positive values of the characteristics of foams can be adopted of various types. The connection between phenomena can be not only linear, but also non-linear. In this case, nonlinear correlation can be realized in the form of parabolic and other equations of a certain degree. The calculation of the interaction is carried out on the basis of second-order parabolic equations. Approximation in the form of second-order equations does not greatly improve the convergence, but the possibilities for extrapolating statistical models are reduced.
While carrying out work to ensure the technical safety of buildings and structures in the Arctic regions, one of the important stages is geodetic monitoring. Provided that the complexity of ensuring ...the stability of reference points in the Arctic zone when conducting geodetic monitoring of engineering facilities, geodetic networks should preferably be equated as free, i.e., to equate the reference points on a par with the defined ones. The present article provides variants how to to equalize geodetic networks to carry out a search method of non-linear programming, which is given a theoretical substantiation for the method and the order of estimating accuracy of the outcomes of the equalization of the generalized Makarov method. The procedure of pseudo transformation of a matrix of normal equations of unknowns with the application of an algorithm of a search method of nonlinear programming is given. The correctness of the application of the search method to the pseudo transformation of a matrix of normal equations of unknowns by the coincidence of outcomes of the pseudo transformation of the given matrix based on skeleton expansion done in M. Mashimov's work is proved. Equalization and estimation of accuracy of free leveling network with the application of search method and generalized Makarov's method are carried out. The conclusion about the correctness of the application of a search method of nonlinear programming for the processing of free geodetic networks at the performance of geodetic monitoring of buildings and constructions in the Arctic area is made.
This research provides a data-driven assessment of dynamic communication in emergency response, highlighting important findings supported by actual data. In comparison to police officers in law ...enforcement situations, EMTs responded to medical crises 25% quicker, according to the response time research. When it came to communication accuracy, firemen performed at a 96% accuracy rate during fire situations, compared to a 91% accuracy rate in law enforcement circumstances. When compared to law enforcement situations, there was a 3% improvement in the completeness of information shared in fire incidents. Additionally, compared to accident situations, police officers' communication efficacy in law enforcement occurrences was 2.3% greater. These results highlight how crucial customized communication plans, data-driven insights, and technology and training integration are to maximizing dynamic communication in emergency response systems.
The article is devoted to the issue of preserving the architectural heritage of the outstanding Russian engineer V.G. Shukhov. Three objects are considered: the Moscow Radio Tower on Shabolovka, the ...“Shukhov Prolet” of the Sheet Rolling Shop and the Water Tower, located in the city of Vyksa, Nizhny Novgorod Region. The main design parameters of these structures and the results of their technical examination, the emergency response measures taken to ensure the safety of the Radio Tower in Moscow, and recommendations for the restoration of all three structures with the transfer of the Sheet Rolling Shop and the Water Tower to the central part of Vyksa are presented. It is planned to reconstruct the historical appearance of the buildings, as well as to improve the surrounding area. It is supposed to restore the geometric shape of the section by laser deposition of powder metal, and only if it is impossible to restore the element, its replacement is provided. To preserve the historical appearance, the joints of steel structures will be bolted, imitating rivets. In the course of excavation, archaeological research is planned, since within the boundaries of the construction site (the city of Vyksa) there may be areas of preserved cultural strata of the cultural heritage site “Estate-industrial complex, XVIII-XIX centuries”.
This article presents the results of a research of the sleep patterns of 200 students living in dormitories in Moscow. The average duration of night sleep in the surveyed group was 6h 37min. The ...proportion of students satisfied with the duration of night sleep was 36.5 %. Daily activity rhythms, in particular, the going to sleep and awakening time at the same time, are compiled by 47.5 % of the surveyed students. 86.5 % of students go to bed after midnight. The most late going to sleep time is observed among students of the 1st and 4
th
years. 37 % of students suffer from insomnia, which is most often caused by stress and work in extracurricular time. It was found that the best indicators of well-being and learning ability were observed at night sleep duration from 6 to 8 hours. When the duration of night sleep is less than 6 hours, there was a deterioration in the state of students’ health, wellbeing and learning ability. It was revealed that 92.2 % of students who fall ill three or more times a year have a night sleep duration of less than 6 hours.
Necessity and reasonability to use gapless connection between contact surfaces of lining straps of work rolls chocks and facing strips of housings (inner lining straps of back-up rolls chocks) to ...reduce dynamic horizontal forces during rolling and increase durability of equipment are considered. Technical solution is described on base of roughing reversing rolling stand of thick sheet rolling mill 3000 of PJSC ‘ILYICH iron and steel works’ (Mariupol city, Ukraine) which can be used on most heavy loaded sheet and tube rolling mills.
Fencing composite structures with thin-sheet metal cladding and effective thermal insulation are widely used. They are especially effective in hard to reach, remote, seismic areas, in areas with ...harsh climates. There is a problem of estimating the real random loading of snow, wind, ice, temperature loads and others according to Roshydromet, when the strength, heat engineering, dielectric, and other structural parameters are random and changes in which from the allowable area lead to failures.The paper provides an assessment of the reliability of enclosing structures of buildings based on quantitative signs of impacts (wind, snow and permanent), as well as the results of statistical evaluation of factory acceptance tests. This paper discusses to exhaust the resource - the strength of the middle layer of the structure during shear.
Field modeling of heat transfer in atrium Nedryshkin, Oleg; Gravit, Marina; Bushuev, Nikolay
IOP conference series. Earth and environmental science,
10/2017, Letnik:
90, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The results of calculating fire risk are an important element in the system of modern fire safety assessment. The article reviews the work on the mathematical modeling of fire in the room. A ...comparison of different calculation models in the programs of fire risk assessment and fire modeling was performed. The results of full-scale fire tests and fire modeling in the FDS program are presented. The analysis of empirical and theoretical data on fire modeling is made, a conclusion is made about the modeling accuracy in the FDS program.
The paper considers the issues of crack resistance of multilayer systems made of asphalt concrete, namely: the causes and features of the occurrence and development of "reflected" cracks are ...investigated. A study of the operational state of highways was carried out and the prerequisites for the formation of defects on the pavement were determined, including the regional features of the work of the road structure. The authors comprehensively studied the causes of internal and external defects and deformations of asphalt concrete pavements. The most popular technologies for sealing cracks and restoring the pavement are considered, the experience of repairing roads in the western part of Russia, Europe and the USA is also investigated. The results of determining the rate of formation and development of defects in the surface of the exploited roads are presented. In laboratory conditions, work was carried out to simulate cracks in two-layer samples of fine-grained asphalt concrete. Test specimens with a height and diameter of 10 cm were made by molding and compacted in layers, a crack was laid in the lower layer of the specimen. After gaining strength, the samples were tested for compression. Analysis of the results of physical modeling made it possible to put forward an assumption about the existence of a relationship between the presence (absence) of internal defects in the coating and the strength of the structure. To confirm the hypothesis, mathematical modeling of the operation of a two-layer system in the GenIDE32 software package was performed. Evaluation of the stress-strain state by the finite element method showed the presence of characteristic zones of system weakening around the defect area. In a two-layer system, there is an increase in internal stresses and strains around the crack, as well as a decrease in the overall strength (stability) of the system. In conclusion, the influence of internal defects of asphalt concrete coatings on the process of formation of "reflected" cracks were identified.
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