Melting temperature of graphene

We present an approach to the melting of graphene based on nucleation theory for a first order phase transition from the 2D solid to the 3D liquid via an intermediate quasi-2D liquid. The applicability of nucleation theory, supported by the results of systematic atomistic Monte Carlo simulations, provides an intrinsic definition of the melting temperature of graphene, $T_m$, and allows us to determine it. We find $T_m \simeq 4510$ K, about 250 K higher than that of graphite using the same interatomic interaction model. The found melting temperature is shown to be in good agreement with the asymptotic results of melting simulations for finite disks and ribbons of graphene. Our results strongly suggest that graphene is the most refractory of all known materials

Self-Consistent Screening Approximation for Flexible Membranes: Application to Graphene

Crystalline membranes at finite temperatures have an anomalous behavior of the bending rigidity that makes them more rigid in the long wavelength limit. This issue is particularly relevant for applications of graphene in nano- and micro-electromechanical systems. We calculate numerically the height-height correlation function $G(q)$ of crystalline two-dimensional membranes, determining the renormalized bending rigidity, in the range of wavevectors $q$ from $10^{-7}$ \AA$^{-1}$ till 10 \AA$^{-1}$ in the self-consistent screening approximation (SCSA). For parameters appropriate to graphene, the calculated correlation function agrees reasonably with the results of atomistic Monte Carlo simulations for this material within the range of $q$ from $10^{-2}$ \AA$^{-1}$ till 1 \AA$^{-1}$. In the limit $q\rightarrow 0$ our data for the exponent $\eta$ of the renormalized bending rigidity $\kappa_R(q)\propto q^{-\eta}$ is compatible with the previously known analytical results for the SCSA $\eta\simeq 0.82$. However, this limit appears to be reached only for $q<10^{-5}$ \AA$^{-1}$ whereas at intermediate $q$ the behavior of $G(q)$ cannot be described by a single exponent.Comment: 5 pages, 4 figure

Atomistic simulations of structural and thermodynamic properties of bilayer graphene

We study the structural and thermodynamic properties of bilayer graphene, a prototype two-layer membrane, by means of Monte Carlo simulations based on the empirical bond order potential LCBOPII. We present the temperature dependence of lattice parameter, bending rigidity and high temperature heat capacity as well as the correlation function of out-of-plane atomic displacements. The thermal expansion coefficient changes sign from negative to positive above $\approx 400$ K, which is lower than previously found for single layer graphene and close to the experimental value of bulk graphite. The bending rigidity is twice as large than for single layer graphene, making the out-of-plane fluctuations smaller. The crossover from correlated to uncorrelated out-of-plane fluctuations of the two carbon planes occurs for wavevectors shorter than $\approx 3$ nm$^{-1}$Comment: 6 pages, 7 figures

Analysis of the Northern (Arctic) federal university’s language learning model

В статье авторами приводится метод моделирования для построения языкового образования в современном университете, подчёркивается роль языковой политики университета в определении пути развития языкового образования. Рассматривается модель языкового образования, представленная в программе развития САФУ, и анализируются в соответствие с принципами непрерывности образовательного процесса. На основе этого анализа предлагается собственная модель языкового образования, и обосновываются её преимущества.The authors of this article give method of modeling to scheme language learning at modern university; emphasize the role of language policy at university to determine ways of language learning development. The model of language learning given in the program of development of NArFU is examined and analyzed in compliance with principles of the life-long education. On basis of this analysis the authors’ model of language learning is given and its advantages are proved

АНАЛІЗ ПІДХОДІВ ДО ФОРМУВАННЯ КОМАНДИ УПРАВЛІННЯ ПРОЕКТАМИ НА ПРИКЛАДІ ЕКІПАЖІВ МОРСЬКИХ СУДЕН

In the article, the authors examined the problematic aspects of project management; the study focuses on the optimization of the crew of the vessel — the project team based on the concept method. Within the framework of the approach proposed by the authors, a model has been developed for the formation of the crew of the vessel — the project team, which allows one to identify its composition, the most suitable and stable (balanced) for managing a specific project in terms of its competence, complementarity of crew members on the vessel (synergism) and its psychological characteristics. The use of the project management system implies the creation of a special group, the crew of a ships (project team), which becomes an independent participant of the project and manages the process of sending and forming the crew of the vessel within the project being implemented. This group is created for the period of project implementation and after its completion it is dissolved. Human resource planning — an estimate of the size and composition of human resources in the future. The project team is the main creative component of creating the end product or service in the projects. The project team is a group of employees who work directly on the project and are subordinate to the project manager. Unfortunately, there is no adequate model and method that would allow simultaneous optimization of the composition of personnel, teams, crew. The use of deterministic models and methods in solving our problem is ineffective, since there is an inability to predict the entire list of works when planning teams of projects, crews.Розглянуто проблемні аспекти управління проектами, досліджено питання оптимізації екіпажу судна — команди проекту на базисі концептуального методу. У рамках запропонованого підходу розроблено модель формування екіпажу судна — проектної команди, що дозволяє виявити її склад, найбільш придатний і стійкий (збалансований) для управління конкретним проектом щодо його компетентності, взаємодоповнюваності членів екіпажу на судні (синергізму) та його психологічних особливостей. Використання системи управління проектами передбачає створення спеціальної групи, екіпажу (команди проекту), яка стає самостійним учасником проекту і управляє процесом відправлення та формування екіпажу судна в рамках проекту, що реалізується. Ця група створюється на період реалізації проекту і після його завершення її розпускають. Планування людських (трудових) ресурсів (human resource planning) — оцінка розмірів і складу людських ресурсів у майбутньому. Проектна команда — основний креативний компонент створення кінцевого продукту або послуги у проектах. Команда проекту (project team) — група співробітників, які безпосередньо працюють над здійсненням проекту і підлеглі керівникові проекту. На жаль, адекватної моделі та методу, які б дозволили одночасно проводити комплексну оптимізацію складу персоналу, команд, екіпажу, на сьогодні не існує. Застосування детермінованих моделей і способів при вирішенні нашого завдання неефективне, оскільки неможливо передбачити весь перелік робіт при плануванні команд проектів, екіпажів суден

NEW 3-(2-PYRIDYL)-1,2,4-TRIAZOLE DERIVATIVES AND THEIR PALLADIUM (II) COMPLEXES

The article is devoted to investigation of coordination compounds of palladium (II) with 3-(2-pyridyl)-1,2,4-triazole derivatives containing amino groups. We syntesized 4 ligands and 4 new coordination compounds. An interesting after removing of BOC-protection, NH2-group is still uncoordinated. In 1H NMR spectra of complexes was a significant shift of the ortho-pyridine proton in a low-field area, which prove proposed structure. This may be due to its closeness to the lone electron pair of the nitrogen cycle of the second triazole ligand

A Conceptual Approach to Managing Labor Resources in the Maritime Industry

Motivation: More than 70% of accidents in the fleet are due to the "human factor" - a wide range of psychological and psychophysiological qualities of the person, which in some way affect the result of its operations. Statistics of major ship accidents in recent decades show that not a single element of the shipping system is aloof from them. That is ship crews, shipowners, charterers, consignees, classification societies and other organizations associated with maritime transportation form a “chain†of risk. The correct combination of human abilities and machine capabilities significantly increases the efficiency of the "person - machine" systems and determines the optimal use by a person of technical means for their intended purpose. Unfortunately, an adequate model that would allow both quantitative and qualitative optimization of the project team, especially in conditions of incomplete determination of the volume of work, today does not exist. In addition, the existing methods do not take into account the specifics of the formation and conditions for the implementation of projects by such teams as the ship's crew, namely the increased level of danger, the inability to make replacements during the voyage, the international composition, the language barrier, etc. In this context, the issue of human resources management as a basic element of achieving the efficiency of project implementation in the field of maritime transport is also urgent, which implies an emphasis on the problem of project-oriented management of crewing and activity of the crew of marine vessels. The issue of clarifying the role, importance and key elements of HRM strategies and policies in the implementation of these projects requires special consideration. The aim of the study is to develop methodological approaches for the forming of quantitative and qualitative composition and effective management of project teams, as a variable component of the project management system of marine vessels.Novelty: Develop methodological approaches for the quantitative and qualitative composition of project teams, as a variable component of the project team on the example of crews of marine vessels. The task of acceptability of the structure, quantitative and qualitative composition of the team was solved. The terminological base of project management was developed by more clearly defining the concepts of “project team†and “project management teamâ€. The approach to the organization of the crewing company recruitment system to work on ships was proposed.Methodology and Methods: In this scientific research to achieve the objective and test the hypotheses suggested in the research paper was used: 1) project teams methodology in project management, in particular, the Project Management Institute Classification (2017) of types of teams in the organizational structure of complex projects and in their management and the taxonomy of SNCB Version 4.1 are designed to provide a comprehensive professional assessment of the level of training of project managers; 2) method for calculating the size of the project team is based on the condition of minimizing its number, which reduces operating costs for the implementation of the project by the Ringelmann effect is known - a formula that provides the ability to quantify and optimize the parameters of the project team; 3) the method of planning of the minimum crew of The International Association of Sea Pilots considering the role of the “human†element in preventing accidents and environmental pollution (the ISM Code and the STCW Convention 78/95 as amended).Data and Empirical Analysis: For the purpose of the study, data were collected and empirical analysis was conducted concerning the analysis of the accident rate of ships and crews for 2009-2019 (causes of accidents: damage to the case and mechanisms; clash; shipwreck and landing; fires and explosions; submergence; contact with the ground; varied; hostilities), that can have a result severe damage or loss of the ship.Policy Considerations: Human factor is the most important aspect that determines the efficiency of shipping development; maintaining of technical and technological processes of the ship puts certain requirements to the quantitative and qualitative composition of the team, deviation from which leads to the occurrence of certain risk events; formation of an effective model of ship's crew manning is the main link in ensuring effective shipping project management

Scaling Properties of Flexible Membranes from Atomistic Simulations: Application to Graphene

Structure and thermodynamics of crystalline membranes are characterized by the long wavelength behavior of the normal-normal correlation function G(q). We calculate G(q) by Monte Carlo and Molecular Dynamics simulations for a quasi-harmonic model potential and for a realistic potential for graphene. To access the long wavelength limit for finite-size systems (up to 40000 atoms) we introduce a Monte Carlo sampling based on collective atomic moves (wave moves). We find a power-law behaviour $G(q)\propto q^{-2+\eta}$ with the same exponent $\eta \approx 0.85$ for both potentials. This finding supports, from the microscopic side, the adequacy of the scaling theory of membranes in the continuum medium approach, even for an extremely rigid material like graphene

НАУКОВО-МЕТОДИЧНЕ СПРЯМУВАННЯ ОРГАНІЗАЦІЇ ТА КОНТРОЛЮ САМОСТІЙНОЇ РОБОТИ СТУДЕНТІВ У НМУ ІМЕНІ О. О. БОГОМОЛЬЦЯ

The article analyzes the quality level of organisation and methodological basis of self learning, namely, among students of clinical disciplines at the Medical Faculty of Bohomolets National Medical University as an essential component of effective training of specialists. It covers the basic aspects of University internal management system that deals with quality of education as regards the implementation of scientifically grounded approaches to improve the organization of self learning among students.У статті висвітлено результати аналізу якості організації самостійної роботи студентів та її методичного забезпечення з клінічних дисциплін на медичних факультетах Національного медичного університету імені О. О. Богомольця як важливого компонента у системі ефективного управління підготовкою фахівців. Описано основні аспекти функціонування внутрішньовузівської системи управління якістю освіти у визначенні та реалізації науково обґрунтованих підходів до удосконалення організації самостійної роботи студентів.