Treatment of Determination Method for Strength Characteristics of Reinforcing Steel by Using Thread Cutting Method after Temperature Influence

The object of the study is the coefficients of asymmetry and excess of the selective distribution of hazardous parameters of the gas environment during material fires. The practical importance of the research lies in the use of measures of asymmetry and kurtosis for early detection of fires. The measures of asymmetry and kurtosis for sampling the final size of an arbitrary dangerous parameter of the gas environment are substantiated. The proposed measures make it possible to investigate the peculiarities of the coefficients of asymmetry and kurtosis in relation to the selective distribution of an arbitrary dangerous parameter of the gas environment. At the same time, it becomes possible to numerically determine the degree of difference of the sample distributions of dangerous parameters from the Gaussian, as well as the features of such measures. Experiments were conducted to determine the degree of asymmetry and excess of dangerous parameters of the gas environment in the laboratory chamber at the intervals of the absence and presence of ignition of the test materials. The obtained results indicate that on the intervals of absence and presence of fires, the selective distributions of dangerous parameters of the gas environment differ from the Gaussian distribution. Distributions are complex and individual in nature. Features of measures of asymmetry and kurtosis depend on the type of ignition material. It was established that the maximum values of the modulus of increase in the degree of asymmetry are characteristic for the carbon monoxide concentration (2.939) during the ignition of paper, for the smoke density (3.098) during the ignition of textiles, as well as for the temperature during the ignition of alcohol (7.163) and wood (1.06). It was determined that the maximum values of the modulus of excess measure increase are characteristic for smoke density (4.678) when paper, wood (1.652) and textiles (28.932) ignite, as well as for temperature (49.377) when alcohol ignites

Section: The Object Of the Study Is The Coefficients Of Asymmetry And...mentioning

confidence: 99%

Revealing the peculiarities of asymmetry and kurtosis coefficients of gas medium parameters in premises during fire

Pospelov,

Meleshchenko,

Bezuhla

et al. 2023

“…Paper [9] considers measures to limit the spread of landscape fires. In [10], the thermal effect of fire on steel structures is considered but the dynamics of changes in the parameters of the combustion cell were left out. In [11], the environmental characteristics of fire extinguishing agents used for extinguishing oil product fires are considered.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Justifying the experimental method for determining the parameters of liquid infiltration in bulk material

Abramov

Basmanov

Oliinik

et al. 2022

The object of this study is the process of impregnation of liquid into the bulk material, in particular, into the soil. Determining the impregnation parameters is a relevant task when assessing the consequences of an emergency spill of a hazardous liquid. Infiltration of liquid into the soil leads to pollution of water resources. However, the greatest danger is the ignition of the spill of a combustible liquid. Based on the Green-Ampt model, a mathematical description of the impregnation of liquid into bulk material was built. It is a system of two ordinary differential equations of the first order, one of which describes the reduction of the thickness of the liquid layer on the surface, and the other describes the dynamics of the impregnation of liquid into depth. The solution to the system was derived in the form of time dependence on the depth of impregnation. An experimental study was conducted on the example of impregnation of crude oil in the sand. To this end, sand was poured into a vertical measuring glass cylinder. After that, the liquid was poured and a video recording of the impregnation process was carried out. By processing the video recording, the depth of impregnation and the corresponding time were determined. The results of the study show that the relationship between the thickness of the liquid layer on the surface of the sand and the depth of impregnation is linear in nature: the relative deviation of linear approximation from experimental data does not exceed 3.5. By expanding the logarithmic function contained in the solution to the system of differential equations into the Taylor series, a polynomial dependence of time on the depth of impregnation was established. To determine the coefficients of the polynomial based on the experimental data, the least squares method was used. In this case, the approximation error after the first minute after spilling does not exceed 10 %. The proposed method could be used to account for seepage in the model of liquid spreading on the ground and the burning model of a flammable liquid spill

“…P leads to poisoning, injuries, and death of people [7]. At the same time, there is damage to the O themselves, as well as to the elements of their construction [8]. The use of fire extinguishers and means of extinguishing P lead to a negative impact on the environment, causing pollution of reservoirs [9], soil, and also atmospheric air [10].…”

Section: Introductionmentioning

confidence: 99%

Method for early ignition detection based on the sampling dispersion of dangerous parameter

Pospelov,

Rybka,

Krainiukov

et al. 2024

The object of the study is the selective dispersion of dangerous parameters of the gas environment during material fires. The practical importance of research consists in using the difference of sample dispersions of dangerous parameters of the gas environment on the intervals of absence and presence of ignition of materials for detection of ignition. The theoretical substantiation of the method of detecting fires in premises based on sample dispersions of current measurements of an arbitrary dangerous parameter of the gas environment, corresponding to the general populations of reliable absence and presence of fire, has been carried out. The method, at a given level of significance, determines the unbiased uniformly most powerful fire detection rule. This makes it possible to determine how much differences in sample variances are significant with a given level of significance and are caused by ignition or are random factors. Laboratory experiments were conducted to verify the proposed method. It was established that the influence of ignition on the value of the difference in the sample dispersion at the corresponding intervals of monitoring the carbon monoxide concentration, smoke density, and temperature of the gaseous environment of the laboratory chamber is different and depends on the type of ignition material. At the same time, the minimum difference of the sample dispersions is characteristic for observing the smoke density for all the studied materials. However, early detection of ignition of alcohol, paper, wood, and textiles when observing the smoke density is carried out when the threshold is exceeded by 9.01, 5.31, 2.13 and 2.55 times, respectively. It is shown that the method of early detection of fires, which is based on the detection of significant differences in sample dispersions of data from the relevant general populations