Self-perception of Physical Appearance in Adolescents: Gender, Age and Ethnic Aspects

The study used cross-sectional data of 462 girls and 372 boys of Russian ethnicity and 90 Kalmyk girls 12-17-year-olds. In both groups children were examined by the same researchers according to the same research protocol. All of the observations have been performed in agreement with bioethical procedures; protocols of consent were filled either by the subject (elder children) or by his/her parent(s). Standing height, weight, body circumferences and skinfolds thickness were taken on each individual according to the standard technique. Body mass index (BMI) was calculated. In Arkhangelsk city 114 boys and 172 girls among the total number of studied subjects filled in the questionnaires, and in Elista – 34 girls among 90. Data sets were divided according to sex, age, somatotypes and ethnicity. The results of the present study showed significant correlations between somatotypes of the subjects, their BMI and self-estimation of their physical appearance. In self-perception of one’s body, weight was the most important characteristics in girls, while in boys it was stature. No differences were found in most of self-evaluation scores between Russian girls of Arkhangelsk city and Kalmyk girls of Elista, apart from the fact that the latter had lower scores in the estimation of their body shape, possibly because they were fatter. The strategies chosen by the adolescents for modifications of their bodies in their quest for »ideal« figures were in favor of dieting versus physical activity, which puts the question of popularization of physical culture and sports on a nation-wide scale

Secular Changes in Mongolia: Shift in Tempos of Growth

The patterns of secular changes in children and adolescents of the city of Ulаan-Baatar in the Republic of Mongolia measured in 2010–11 by the authors and in the group of children observed by Uranchimeg in the same place in 19891 have been analyzed. Total number of the investigated children and adolescents from 9 to 17 years of age was 1351. The last survey was conducted in accordance with bioethical procedures. The program included standard anthropometric measurements, descriptive characteristics2 and pubertal stages evaluation3. Mean age of development of secondary sexual characteristics was calculated graphically. For most of the anthropometric indices significant differences between the Mongolian teenagers of two series of measurements were revealed. The patterns of secular changes in body size confirmed the interaction of »tempo and amplitude«4: significant changes in pubertal growth were observed with the same average values at 16–17-year old boys and girls. The increase in body circumferences observed in modern Mongolian schoolchildren was possibly based on the increase of body fat component, parallel to the global trend worldwide

Surface texturing for tribological applications: a review

Surface texturing is one of the surface modification techniques which deliberately change the texture of the surface, in order to improve, among other things, its tribological performance. This is obtained through different patterns, which can be on micro or nano scale, created on the contact surfaces. The performance of a textured surface depends on the shape, geometry and pattern of the surface texture and the operating condition of the components in contact. There is a number of various techniques for surface texturing, among which laser surface texturing is most often used. The different surface texture shapes, different textured area ratios and patterns, different lubrication regimes with different contact geometries and materials have been subject of theoretical and experimental research for many years. This paper reviews the state-of-the-art of researches that consider various surface texturing for tribological application, as well as its effect on performance enhancement. Conclusions of this paper may provide guidance for optimal design of surface textures in practical engineering applications

Surface texturing for tribological applications: a review

Surface texturing is one of the surface modification techniques which deliberately change the texture of the surface, in order to improve, among other things, its tribological performance. This is obtained through different patterns, which can be on micro or nano scale, created on the contact surfaces. The performance of a textured surface depends on the shape, geometry and pattern of the surface texture and the operating condition of the components in contact. There is a number of various techniques for surface texturing, among which laser surface texturing is most often used. The different surface texture shapes, different textured area ratios and patterns, different lubrication regimes with different contact geometries and materials have been subject of theoretical and experimental research for many years. This paper reviews the state-of-the-art of researches that consider various surface texturing for tribological application, as well as its effect on performance enhancement. Conclusions of this paper may provide guidance for optimal design of surface textures in practical engineering applications

Influence of the amount of metal-containing additive on performance characteristics of lubricant based on rapeseed oil

The paper exposes experimental results of the performance characteristics (coefficient of friction, contact temperature and wear) of the biolubricant based on rapeseed oil. The amount of commercial metal-containing additive in formulated lubricant was 1, 1.5, 3 and 5 %. All results were compared with the results obtained for the base rapeseed oil. They showed that the metal-containing additive in rapeseed oil reduced all characteristics (coefficient of friction, contact temperature and wear). It was also found that the dependence of all characteristics on the amount of additive is nonlinear and that there is an optimal value of it

Use of computer support as motivation for studying language information units for carrying out professional maritime activities in communication conditions

The relevance of studying English marine terminology is due to work with original materials as part of professional activities in negotiating with coast stations, port authorities and various services of foreign countries. One has to deal with a huge number of information units (IU) required in communication. The problem consists in a comparative consideration of the language terminological processes in professional maritime activities (PMA). The aim of the study is to motivate the study of language IU using computer support for the implementation of PMA in communication. The research methods include testing of experimental groups in training and control modes, using “STEP” computer training system; testing control groups using paper media. IMO standard phrases are the language basis of the test tasks. As a result of the scientific research the possibility of studying IU in a short period of time using a computer program in training and control modes has been presented. It has been experimentally revealed that computer support promotes the development of reflective personality traits through inducing self-assessment of the ability to rely on the IU studied and organizing one's own actions for their assimilation; comprehension and formation of one’s own attitude to IU and motivation for their study; forecasting mutual understanding in relations with a possible partner based on the material being studied; current self-organization of the sequence of actions of perception, reproduction and rethinking of IU and self-assessment of their assimilation. This leads to high motivation of the learning process in order to master professional activities

Investigation of the Convergence of a Multi-Grid Algorithm for Solving the Task of Pressure in the Thin Lubricating Film of the Non-Newtonian Fluid

The article describes a multi-grid algorithm for integrating the Reynolds equation for hydrodynamic pressures in the lubricating film of a heavy-loaded journal bearing. This equation is the basic one in solving the tasks of designing friction units of piston- and rotary machines. Lubrication sources of various configurations in the form of grooves and holes located on the friction surfaces were taken into account. The version of the multi-grid algorithm developed by the authors is based on Brandt’s work. At each level of grids, not only the convergence of the solution is controlled, but also the rate of convergence. The pressure equation was approximated by finite differences using the control volume method and passed to a system of algebraic equations, which were solved by the Seidel method. Bessel formulas were used as the interpolation operator. The function for taking into account the non-Newtonian properties of the lubricant is based on the power law. Comparison of the developed algorithm with other versions showed high efficiency. The use of multi-grid algorithms makes it possible to perform multi-variant calculations of the dynamics of heavily loaded bearings. As a result of the calculations, the characteristics of the connecting rod bearing of the heat engine, as well as the multilayer bearing of the turbocharger, are presented