Fast diffusion of graphene flake on graphene layer

Diffusion of a graphene flake on a graphene layer is analyzed and a new diffusion mechanism is proposed for the system under consideration. According to this mechanism, rotational transition of the flake from commensurate to incommensurate states takes place with subsequent simultaneous rotation and translational motion until the commensurate state is reached again, and so on. The molecular dynamics simulations and analytic estimates based on ab initio and semi-empirical calculations demonstrate that the proposed diffusion mechanism is dominant at temperatures T ~ Tcom, where Tcom corresponds to the barrier for transitions of the flake between adjacent energy minima in the commensurate states. For example, for the flake consisting of ~ 40, 200 and 700 atoms the contribution of the proposed diffusion mechanism through rotation of the flake to the incommensurate states exceeds that for diffusion of the flake in the commensurate states by one-two orders of magnitude at temperatures 50 - 150 K, 200 - 600 K and 800 - 2400 K, respectively. The possibility to experimentally measure the barriers to relative motion of graphene layers based on the study of diffusion of a graphene flake is considered. The results obtained are also relevant for understanding of dynamic behavior of polycyclic aromatic molecules on graphene and should be qualitatively valid for a set of commensurate adsorbate-adsorbent systems.Comment: 33 pages, 6 figure

Individual personality traits as predictors of intra-organizational vertical career growth of employees

The paper is devoted to the research on the influence of individual personality traits on the success of intra-organizational vertical career growth of employees, the indicator of which is the promotion of employees in their position (status) in the organization, taking into account their speed of passing the career levels. The article analyzes the types of career, criteria and factors of career growth, including personality characteristics in the context of their influence on career processes. The article presents the results of an empirical study of the managers of JSC Concern Energomera, Stavropol (Russia), which determined the relationship between the success rate of intra-organizational vertical career growth and individual personality characteristics, manifested in the level of mental tension (anxiety, suspicion, inclination to risk, spontaneity and emotional sensitivity) and expressiveness. The authors did not find statistically significant contribution of regulatory properties and indicators of general mental abilities to distinguishing groups of employees with high and low indicators of vertical career growth. The averaged personal profiles of employees with high and low indicators of vertical career growth are presented.peer-reviewe

The introduction of a mixed system of maintenance and repair of metal-cutting equipment

The article provides a comparative analysis of the Russian and foreign systems for the maintenance and repair of metal-cutting equipment. The limitations of the application of systems of universal maintenance of equipment, scheduled preventive maintenance and repair by state are analyzed. The influence of the age of the equipment and the percentage of the repair plan on the amount of emergency shutdowns is shown. The main stages of the introduction of mixed service and repair systems are highlighted. Criteria for classifying equipment groups are proposed for the selection of repair and maintenance systems. Examples of typical diagnostic signs of malfunctions of metal-cutting equipment and statistical time of emergency shutdown after their detection are given. The recommendations on planning the need for spare parts and organization of repair work are given. © Published under licence by IOP Publishing Ltd

Prediction of small R&D enterprise development based on the index of project portfolio entropy

The article deals with the problems of R&D enterprise management and some aspects of its strategy formation. The method for predicting the development of R&D-driven enterprises at the early stages of their life cycle, such as the “emergence” and “growth” is shown. The study, whose results are presented in this article, is to prove the hypothesis that the formation of the development strategy of an R&D-driven enterprise can be based on the prediction of points of transition from one phase of the life cycle of the company to another, i.e., “bifurcation” points. In this study, an analysis of the classical approaches to the strategy development of the enterprise, including contemporary life cycle management literature is given. Based on the analysis, we proposed an approach to forecasting the transition points of the lifecycle of the enterprise, which is based on a probabilistic assessment of the commercialization of projects, their technical processing, as well as the degree of disorder in the company’s project portfolio. The study proposes to assess the degree of structuring of the portfolio as a probabilistic object with information entropy, with its growth to critical values being a criterion for predicting the transition of the enterprise to a new stage of its life cycle. The hypothesis put forth in the article is supported with calculations, correlation analysis and comparison of the level of company’s performance and the level of the entropy of its portfolio over a time period. The calculation was done based on a sample which included R&D-driven enterprises of the Ural and Siberian autonomous regions of Russia. The study found an inverse relationship between the level of income of R&D-driven enterprises in the early stages of their development and the level of entropy of their project portfolio. Typical strategic decisions on project portfolio management on the basis of the forecast are proposed. The results can be used in strategy management.В данной статье рассмотрены вопросы управления деятельностью предприятия научно-технической направленности и некоторые аспекты формирования его стратегии. Представлен метод прогнозирования развития предприятий научно-технической сферы на ранних стадиях жизненного цикла, таких как «зарождение» и «рост». Целью исследования, результаты которого представлены в данной статье, является доказательство гипотезы о том, что формирование стратегии развития предприятия научно-технической сферы может быть основано на предсказании возникновения точек перехода от одного этапа жизненного цикла предприятия, к другому - точек «бифуркации». В рамках данного исследования был проведен анализ классических подходов к разработке стратегии предприятия, в том числе современной литературы по вопросам управления жизненным циклом предприятия. Исходя из результатов анализа, был предложен подход к прогнозированию точек перехода этапов жизненного цикла предприятия, основанный на вероятностной оценке коммерциализуемости проектов, их технической проработки, а также степени неупорядоченности совокупности проектов, составляющих портфель предприятия. В статье предлагается оценивать степень структурированности портфеля проектов как вероятностного объекта, обладающего информационной энтропией, достижение которой критических величин, является критерием прогнозирования перехода предприятия к новому этапу жизненного цикла. Выдвинутая в статье гипотеза подтверждается расчетами, корреляционным анализом и сопоставлением уровня показателей эффективности деятельности предприятия с уровнем энтропии портфеля проектов в динамике. Расчет производился по выборке, в которую вошли научно-технические предприятия проектной направленности уральского и сибирского автономных округов. В результате исследования, выявлена обратная зависимость между уровнем доходов предприятий научно-технической сферы на ранних этапах развития и уровнем энтропии портфеля проектов. Предложены типовые стратегические решения по управлению портфелем проектов на основе прогноза. Результаты исследования могут быть применены в стратегическом менеджменте организаций

Ab Initio Calculations of the Walls Shear Strength of Carbon Nanotubes

The dependence of the energy of interwall interaction in double-walled carbon nanotubes (DWNT) on the relative position of walls has been calculated using the density functional method. This dependence is used to evaluate forces that are necessary for the relative telescopic motion of walls and to calculate the shear strength of DWNT for the relative sliding of walls along the nanotube axis and for their relative rotation about this axis. The possibility of experimental verification of the obtained results is discussed.Comment: 4 pages, 1 figur

Interaction of the NO 3pπ (C 2Π) Rydberg state with RG (RG = Ne, Kr, and Xe): potential energy surfaces and spectroscopy

We present new potential energy surfaces for the interaction of NO(C 2Π) with each of Ne, Kr, and Xe. The potential energy surfaces have been calculated using second order Møller-Plesset perturbation theory, exploiting a procedure to converge the reference Hartree-Fock wavefunction for the excited states: the maximum overlap method. The bound rovibrational states obtained from the surfaces are used to simulate the electronic spectra and their appearance is in good agreement with available (2+1) REMPI spectra. We discuss the assignment and appearance of these spectra, comparing to that of NO-Ar

Comparative analysis of cutting fluids

The article contains the results of seven working tests of cutting fluids for metal-cutting equipment. The results of the analysis were evaluated by experts, including process engineers, chemical engineers, foremen and production machine operators in the following areas: turning, drilling, milling, sawing, grinding, threading, boring works. The analysis made it possible to determine the scope of application of cutting fluids depending on the volume and rhythm of the work, the operating conditions of the cutting fluids, the requirements of the design and technological documentation taking into account the final cost of the cutting fluids used. The problem of determining an accelerated system of practical tests for cutting fluids to evaluate the effectiveness of using a particular product before conducting the production tests on machine equipment is considered. For this, criteria for evaluating the cutting fluids are proposed using the weighting method to ensure informed decision-making in the choice of a cutting fluid for admission to full-fledged production tests. © Published under licence by IOP Publishing Ltd

A view at postbariatric hypoglycemia by endocrinologist

The obesity epidemic has led to the growing number of bariatric operations and the expansion of indications for this operation as the most effective method of treatment, that’s why endocrinologists are increasingly faced the challenge of late complications, including postbariatric hypoglycemia. Postbariatric hypoglycemia is a rare but severe metabolic disorder that occurs months or years after upper gastrointestinal surgery. Postbariatric hypoglycemia can be accompanied by severe clinical symptoms and lead to disability and decreasing of the life’s quality. It is difficult to assess the prevalence of hypoglycemia after bariatric surgery due to the lack of clear diagnostic criteria, often a hidden clinical picture and ignorance of doctors and patients about this complication. Hypoglycemia in this case has postprandial and hyperinsulinemic nature. The mechanisms of development of this complication have recently been actively discussed. The exchange of incretins and dysregulation of insulin secretion are the subject of constant research in this area. Understanding the mechanisms of development of this condition makes it possible to develop optimal methods of diagnosis and treatment. The issues of pathophysiology, basic principles of diagnosis and treatment of post-bariatric hypoglycemia will be considered in this review

Bariatric patient: what is the key to success? Case from practice

Surgical treatment in the scope of laparoscopic gastric bypass for morbid obesity and type 2 diabetes mellitus (DM 2) with careful preoperative preparation, a gradual expansion of the diet with the obligatory observance of the recommendations of a nutritionist on the balance of micro- and macronutrients, a gradual increase in the amount of available physical activity in the postoperative period allows not only significantly reduce body weight, but also achieve compensation for obesity-related diseases. The expected development of micro- and macronutrient deficiencies requires an active search for and compensation for these conditions both at the pre- and postoperative stages. The development of postbariatric hypoglycemia confirms the need to comply with dietary recommendations not only at the stage of conservative treatment of obesity and DM 2, but also, no less important, after bariatric surgery

Optimization of the production plan taking according to the customers' strategic importance

The article is devoted to the management of the production plan of the industrial enterprise. Existing approaches to optimization of the production plan are focused mainly on stochastic demand and consider the process of production plan formation. At the same time, many modern industrial enterprises often deal with rush orders in the course of their work. They have to solve the task of changing the formed production plan. If resources are limited, the decision to include an urgent order may result in a failure or a change in the due date of the orders included in the plan. In this regard, it becomes important to take into account the strategic importance of clients to the enterprise. The article proposes a methodological approach to the issue of inclusion or non-inclusion of rush order in the already formed and accepted production plan. The authors have developed a mathematical model of optimization of the formed production plan with the participation of rush order. The model uses Boolean variables to decide whether to include or refuse an order and an additional factor to increase margin income from the order for strategic customers. © Published under licence by IOP Publishing Ltd