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The article presents studies of the influence of scale factor on the strength properties of artificial leathers. The method of simulation modeling enables to determine general patterns of influence of linear dimensions of surface-retentive materials on their strength properties. Simulation was performed by the type and parameter of the law of distribution of the breaking load for specimens consisting of one section, the breaking load of which along the length is constant. In order to identify the influence of the geometric dimensions of the sample on the average value of its breaking load, the same experiments were simulated for man-made leather samples with variable length and width. In order to experimentally verify the preliminary conclusions, an experimental evaluation of the breaking load of artificial leather at various geometric dimensions was carried out. The object of the study was double-layered man-made leather, item Hongxin 11022-16. Sample thickness of 0.9 mm, surface density is 435 g/m2. Tests were conducted using TIME WDW-5 universal testing machine on samples of rectangular shape. As a result of this research, the possibility of practical use of the test simulation method for studying the influence of the scale factor on the strength properties of man-made leather was shown. Цель работы – оценка влияния масштабного фактора на прочностные характеристики искусственных кож, путем использования метода имитационного моделирования, применение которого позволяет выявить общие закономерности влияния линейных размеров поверхностно-протяженных материалов на их прочностные характеристики. Осуществлено моделирование испытаний с учетом вида и параметра закона распределения разрывной нагрузки для образцов, состоящих из некоторого числа n структурных элементов по длине и некоторого числа m структурных элементов по ширине образца. Для выявления влияния геометрических размеров образца на среднее значение его разрывной нагрузки проводилось моделирование таких же экспериментов для образцов искусственной кожи с переменной длиной и шириной. С целью проверки предварительных выводов была произведена экспериментальная оценка разрывной нагрузки искусственной кожи при разных геометрических размерах пробы. В качестве объекта исследования была выбрана двухслойная искусственная кожа артикула Hongxin 11022-16. Испытания проводились с помощью универсальной испытательной машины TIME WDW-5 на пробах прямоугольной формы. В результате проведенных исследований показана возможность практического использования метода имитационного моделирования испытаний для изучения влияния масштабного фактора на прочностные характеристики искусственной кожи.

In this paper, a periodic cosmological model is considered. Previously, it was assumed that the expansion of the universe slows down over time. Theorists proceeded from the assumption that the main part of the mass of the Universe is matter - both visible and invisible (dark matter). On the basis of new observations indicating the acceleration of expansion, it was found that in the Universe there is a previously unknown energy with negative pressure (equation of state). They called it "dark energy". In this paper, a scalar cosmological model is considered. The Lagrangian is derived and the system of equations of motion is obtained. To study the model, a scalar field in the form of a periodic function was chosen. The Hubble parameter, the scale factor, which has the meaning of the radius of the Universe, and in the case of a periodic function of the scalar field, which has an exponential dependence, the density of dark energy, the pressure and the potential of the scalar field are calculated, and their graphs are plotted in the time dependence section from 0 to 2π. To study the inflationary model, the potential is introduced in a power-law form. From it, the parameters of slow rolling through e-folding are derived and a plot of spectral indices for this model is plotted. The results obtained are consistent with the Planck observational data and confirm the correspondence of the model under study with the previously proposed ones. [ABSTRACT FROM AUTHOR]

The question of the physical relationship between the concepts of inert and gravitational masses is considered. The lack of a consensus on the way to solve it is shown. Based on the assumption about the nature of the inert mass, as a result of the interaction of the selected body with all objects of the Universe, some general physical characteristics of the Metagalaxy are consistently evaluated within the framework of standard ideas about its properties. At the same time, in accordance with the basic provisions of modern cosmology, the idea of a uniform distribution of matter in the early universe is applied, which is generally preserved for its current state. In addition, the assumption of its spherical symmetry is used, which is acceptable from the point of view of most cosmological models. On the basis of the hypothesis of equality of the total rest energy of the body and the total gravitational energy of its interaction with the rest of the bodies of the Metagalaxy, a scale factor connecting the mass and radius of the Universe is proposed for consideration. Based on its application, some general parameters of the universe are consistently estimated. At the same time, the obtained estimates of its mass, the number of stars and galaxies in it, as well as the average density of matter in the universe are quite consistent with the results of cosmological studies performed by analyzing observational data and with the hypothesis of "large Dirac numbers". Some ways of practical application of the obtained results are suggested. [ABSTRACT FROM AUTHOR]

Вихревые трубы по эффективности уступают детандерам, но обладают рядом неоспоримых преимуществ, таких как компактность, надежность, многофункциональность. Несмотря на эти достоинства, существует совсем немного примеров эффективного применения вихревых аппаратов в криогенике. В работе рассмотрены проблемы, сопутствующие созданию вихревых охладителей, предназначенных для установок получения неона и гелия. Переход к низким температурам всегда сопровождается миниатюризацией газодинамических аппаратов. В то же время большинство рекомендаций по проектированию вихревой техники относится к высокорасходным устройствам, которые питаются сжатым воздухом при температуре окружающей среды. По этой причине известные геометрические соотношения не всегда применимы при создании криогенных вихревых установок с малыми диаметрами камеры энергоразделения. Экспериментальным путем изучено влияние масштабного фактора в интервале диаметров меньше 10 мм. Показаны преимущества ступенчатого включения низкотемпературных вихревых труб в схемах сепараторов редких газов. Обосновано использование технологического перепада давлений для питания вихревых криогенераторов. При этом работа газодинамических охладителей не требует дополнительных затрат энергии, поскольку в них срабатывается давление сжатого газа, которое ранее бесполезно редуцировалось.

The aim of this paper is to evaluate the scale factor influence in the modeling of shockproof clothing on the basis of an alloy with shape memory effect. The article considers technical possibility of extrapolation of experimental results to other objects to generate the initial data of the mathematical model for dynamics of elastic-plastic deformation of the shockproof device with similarity of features of the external loading.

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Copyright of Journal of Mechanical Engineering the National Technical University of Ukraine 'Kyiv Polytechnic Institute' is the property of National Technical University of Ukraine KPI and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)