Positive behavior in relation to human health

The positive attitude to health in behavior can be expressed both as in positive, and as in negative way, it conducts either to dynamic physical development of an organism, or to a large number of risk factors for healthПозитивное отношение к здоровью в поведении может выражаться как позитивно, так и негативно, это ведет либо к динамичному физическому развитию организма, либо к большому числу факторов риска для здоровь

Electronic structure of unidirectional superlattices in crossed electric and magnetic fields and related terahertz oscillations

We have studied Bloch electrons in a perfect unidirectional superlattice subject to crossed electric and magnetic fields, where the magnetic field is oriented ``in-plane'', i.e. in parallel to the sample plane. Two orientation of the electric field are considered. It is shown that the magnetic field suppresses the intersubband tunneling of the Zener type, but does not change the frequency of Bloch oscillations, if the electric field is oriented perpendicularly to both the sample plane and the magnetic field. The electric field applied in-plane (but perpendicularly to the magnetic field) yields the step-like electron energy spectrum, corresponding to the magnetic-field-tunable oscillations alternative to the Bloch ones.Comment: 7 pages, 1 figure, accepted for publication in Phys. Rev.

Параметрична надійність материкової ділянки Північно-Кримського каналу

Goal. The parametric reliability of the irrigation canal is proposed to be estimated by the correlation coefficient of the corresponding water consumption in the hydraulic structures. An increase in the coefficient indicates an increase in parametric reliability. Operation of the mainland of the north-crimean channel (hereinafter referred to as the pac) takes place in conditions of weakening of parametric reliability, occurrence of retaining phenomena, as a result of which hydrotechnical structures lose water-quality properties. Therefore, the development of methods, methods and recommendations for managing the regime of the north-crimean channel in the territory of the Kherson region and improving the water accounting are topical scientific and applied issues. Methods. Analytical, statistical and correlation analysis. Results. Operation of the channel is carried out through centralized dispatch control of water consumption at hydraulic structures. The purpose of management is to synchronize with the method of the channel water balance of water flow drainage water through all buildings, to ensure a steady flow of water, to distribute it among consumers "on demand" or "on a plan", to regulate the channel of random fluctuations of water consumption due to technologically justified factors, with the time and space inconsistencies of filing and taking water along the length of the channel. The optimization criterion is the parametric reliability of the water distribution in the channel.The obtained results testify to the close correlation (R2) between water consumption in GS and PS-1 buildings, as well as GS and PS-2 in 2001. Thus, in the past, at least in the section of the North-Crimean canal from the main building to PS-2 (Krasnoperekopsk) maintained a sufficiently significant parametric reliability of water distribution. Conclusions. The results of the estimation of the parametric reliability of the main section of the North-Crimean Canal indicate that the most appropriate is the centralized control dispatch control of the water balance in a short time interval, taking into account the existing correlation links between the corresponding water consumption in the hydraulic structures. It is recommended to consider the continental part of the canal as a continuous hit and to regulate its mode of operation, changing the flow of water in the main building.Розглянуто особливості функціонування материкової частини Північно-Кримського каналу в умовах припинення подачі води в Крим, використовуючи водомірні властивості підпірних та випускних гідротехнічних споруд. Наведено результати розрахунків параметричної надійності розподілу води в каналі. Проблеми централізованого управління витратами води на гідротехнічних спорудах в умовах, які не передбачені проектом та шляхи їх вирішення

LC nanocomposites: induced optical singularities, managed nano/micro structure, and electrical conductivity

Microstructure, phase transitions, electrical conductivity, and optical and electrooptical properties of multiwalled carbon nanotubes (NTs), dispersed in the cholesteric liquid crystal (cholesteryl oleyl carbonate, COC), nematic 5CB and their mixtures, were studied in the temperature range between 255 K and 363 K. The relative concentration X=COC/(COC+5CB)was varied within 0.0-1.0. The concentration $C_p$ of NTs was varied within 0.01-5% wt. The value of X affected agglomeration and stability of NTs inside COC+5CB. High-quality dispersion, exfoliation, and stabilization of the NTs were observed in COC solvent ("good" solvent). From the other side, the aggregation of NTs was very pronounced in nematic 5CB solvent ("bad" solvent). The dispersing quality of solvent influenced the percolation concentration $C_p$, corresponding to transition between the low conductive and high conductive states: e.g., percolation was observed at $C_p=1$ and $C_p=0.1$ for pure COC and 5CB, respectively. The effects of thermal pre-history on the heating-cooling hysteretic behavior of electrical conductivity were studied. The mechanism of dispersion of NTs in COC+5CB mixtures is discussed. Utilization of the mixtures of "good" and "bad" solvents allowed fine regulation of the dispersion, stability and electrical conductivity of LC+NTs composites. The mixtures of COC and 5CB were found to be promising for application as functional media with controllable useful chiral and electrophysical properties.Comment: 10 pages, 9 figure

Results of experimental investigations of a flexible active harrow with loosening teeth

ArticleSoil tillage processes significantly affect the growth of cultivated plants; therefore, improvement of various designs and combinations of ploughs is still an actual practical and scientific task. This paper presents investigations of the design of a soil tillage machine consisting of three plough bodies equipped from the lateral side with a module with a flexible active harrow driven by a support wheel. The technological process of tillage by this machine is carried out in such a way that the module of the flexible active harrow is installed at a certain depth of soil tillage. The purpose of this work is an experimental comparative investigation of the quality indicators of the work of a design of the soil tillage working body with a flexible active harrow having loosening teeth. In the process of comparative experimental investigations of the operation of ploughs with a standard flexible harrow and an experimental active harrow having loosening teeth, the soil lumpiness (characterising the quality of crumbling) and water permeability of the obtained soil structure were estimated. An experimental model of this working tool was tested under the production conditions, and it showed advantages of loosening and crumpling the soil compared to the conventional harrows. This can be explained by the fact that the harrow tines, freely mounted on the axes of its links, ensure their oscillatory movements when moving in two different planes, thereby creating conditions for more intense soil disintegration

Academic physical education system: questionnaire survey to rate student satisfaction

Objective of the study was to analyze the student satisfaction with the academic physical education servic

Research of the movement of agricultural aggregates using the methods of the movement stability theory

ArticleThe theory of the movement stability is of crucial practical importance for mobile agricultural machines and machine aggregates, since it determines how qualitative and stable their performance is in a particular technological process. It is especially urgent To ensure stable movement for operation at high speeds of contemporary agricultural aggregates. The aim of this investigation is detailed examination of criteria for the stability assessment of a mechanical system used in agriculture, enabling their wide application in order to study the performance of the system in the case when it is affected by random forces that were not taken into account in the original model. The considered calculation methods and examples of their application make it possible to evaluate the performance of complex dynamic systems without numerical solution of complicated differential equations of the movement in the presence of external disturbances. The considered example of the stability determination of the movement of a trailed cultivator showed that this research method can be successfully used for practical purposes. Besides, a differential equation of disturbed movement has been composed for an actually symmetrical trailed agricultural machine with a particular mass, which moves at a constant forward speed under the impact of summary resistance force running along the symmetry axis of the cultivator and is applied at its centre of gravity. Reduced to normal Cauchy form, this equation was solved on the PC, which made it possible to determine immediately the conditions for stable movement of the trailed cultivator

Research of the movement of agricultural aggregates using the methods of the movement stability theory

The theory of the movement stability is of crucial practical importance for mobile agricultural machines and machine aggregates, since it determines how qualitative and stable their performance is in a particular technological process. It is especially urgent To ensure stable movement for operation at high speeds of contemporary agricultural aggregates. The aim of this investigation is detailed examination of criteria for the stability assessment of a mechanical system used in agriculture, enabling their wide application in order to study the performance of the system in the case when it is affected by random forces that were not taken into account in the original model. The considered calculation methods and examples of their application make it possible to evaluate the performance of complex dynamic systems without numerical solution of complicated differential equations of the movement in the presence of external disturbances. The considered example of the stability determination of the movement of a trailed cultivator showed that this research method can be successfully used for practical purposes. Besides, a differential equation of disturbed movement has been composed for an actually symmetrical trailed agricultural machine with a particular mass, which moves at a constant forward speed under the impact of summary resistance force running along the symmetry axis of the cultivator and is applied at its centre of gravity. Reduced to normal Cauchy form, this equation was solved on the PC, which made it possible to determine immediately the conditions for stable movement of the trailed cultivator