Effect of magnetism on the solution energy of 3p (Al, Si) and 4p (Ga, Ge) elements in iron

The method based on the density-functional theory has been used to study the solubility of 3p (Al, Si) and 4p (Ga, Ge) elements in ferromagnetic and paramagnetic states of bcc iron. To simulate the paramagnetic state, two different approaches have been employed, which were implemented using the SIESTA and LSGF packages. It has been established that the solution energy of all these impurities decreases upon the transition into the paramagnetic state. The solution energies obtained by averaging over the ensemble of unpolarized magnetic configurations agree well with the values obtained in the coherentpotential approximation. At the same time, the allowance for the magnetic polarization in the vicinity of an impurity leads to a decrease in the solution energy, which is most clearly pronounced at temperatures close to TC. The temperature dependence of the solution energies of the impurities in the paramagnetic state is discussed. © Pleiades Publishing, Ltd., 2013

Assessment of Threats to the Security of the Cryptographic Authentication Mechanisms of the Monitor Devices of Vehicles

In accordance with the legislation on transport security, a number of vehicles must be equipped with on-Board control devices containing a cryptographic means of authentication, registration and storage of control data, including key information of the electronic signature. This paper presents a solution to the problem of justification of the adequacy of measures to counter known attacks and methods of discrediting the suggested cryptographic mechanisms and the corresponding protocol, drawn up in the form of a draft national standard and presented in the previous work of the authors devoted to study of its security properties. The solution presented is limited to the consideration of attacks divided into two large classes: passive and active attacks, including temporary attacks based on the study of the response time of one or more participants of the protocol. The analysis of the security threat model of the Protocol generating a common key with the authentication of subscribers intended for use in tachographs installed on vehicles shows that the protocol provides sufficient measures to counter known attacks. The found possible attacks are of a formal nature, not allowing the offender to obtain any additional information in order to discredit the protocol

Solid solution decomposition and Guinier-Preston zone formation in Al-Cu alloys: A kinetic theory with anisotropic interactions

Using methods of statistical kinetic theory parametrized with first-principles interatomic interactions that include chemical and strain contributions, we investigated the kinetics of decomposition and microstructure formation in Al-Cu alloys as a function of temperature and alloy concentration. We show that the decomposition of the solid solution forming platelets of copper, known as Guinier-Preston (GP) zones, includes several stages and that the transition from GP1 to GP2 zones is determined mainly by kinetic factors. With increasing temperature, the model predicts a gradual transition from platelet-like precipitates to equiaxial ones and at intermediate temperatures both precipitate morphologies may coexist.Comment: 9 pages, 8 figure

Personal Branding: Interdisciplinary Systematic Review and Research Agenda

Personal branding has become an important concept in management literature in recent years. Yet, with more than 100 scholarly papers published on the concept to date, it has developed into a fragmented area of research with a diversity of definitions and conceptual boundaries. This paper posits that this heterogeneity of extant research impedes theoretical and empirical advancement. To strengthen the foundation for future work, we review the extant literature and offer an integrative model of personal branding. Through our systematic literature review we identify the key attributes of the construct, establish its clarity by comparing it with similar concepts in its nomological network, and suggest the definitions of personal branding and personal brand based on the reviewed literature. Further, we propose a theoretical model of personal branding summarizing the findings from the reviewed papers. The proposed model outlines the trends conducive to personal branding, as well as its drivers, processes, and outcomes. Finally, we discuss ethical implications of personal branding for both scholarly work and practice. In conclusion, we outline a further research agenda for studying personal branding as a critical career and organizational behavior activity in contemporary working environment

ETEKOS experimental ecological system

The problem of changes in the ecology resulting, for example, in increases in water temperature because of discharges from large thermal power plants is considered. An experiment creating a model of such an ecological system is described

Sub-threshold resonances in few-neutron systems

Three- and four-neutron systems are studied within the framework of the hyperspherical approach with a local S-wave nn-potential. Possible bound and resonant states of these systems are sought as zeros of three- and four-body Jost functions in the complex momentum plane. It is found that zeros closest to the origin correspond to sub-threshold (nnn) (1/2-) and (nnnn) (0+) resonant states. The positions of these zeros turned out to be sensitive to the choice of the $nn$--potential. For the Malfliet- Tjon potential they are E(nnn)=-4.9-i6.9 (MeV) and E(nnnn)=-2.6-i9.0 (MeV). Movement of the zeros with an artificial increase of the potential strength also shows an extreme sensitivity to the choice of potential. Thus, to generate ^3n and ^4n bound states, the Yukawa potential needs to be multiplied by 2.67 and 2.32 respectively, while for the Malfliet-Tjon potential the required multiplicative factors are 4.04 and 3.59.Comment: Latex, 22 pages, no PS-figures, submitted to J.Phys.

Mathematical modeling of thermophysical processes in the wall of the Baker cyst, when intra-cystic fluid is heated by laser radiation 1.47 μm in length

The work is devoted to the study of the theoretical value of destructive influence on normal tissues of an organism by infrared radiation that goes beyond the treated pathological focus. This situation is possible if the direct laser radiation on the tissues is extremely long-acting. The solution to this problem can be the uniform distribution of heat inside the volume through indirect heating of the liquid, which contributes to minimal damage to the perifocal structures. A non-stationary thermophysical model of the process of heat propagation in biological tissues is presented, allowing to carry out studies of energy transfer from internal liquid contents of Baker's cyst heated by infrared laser radiation of a given specific power through a certain thickness of its wall to surrounding biological tissues. Calculation of the spacetime temperature distribution in the cyst wall and surrounding fat tissue is carried out by the finite-difference method. The time of effective exposure to temperature on the entire thickness of the cyst wall was estimated to be 55°C on its outer surface. The safety procedure ensures the exposure duration of this value is not more than 10 seconds. As a result of the calculations carried out, it is established that there are several operating modes of a surgical laser that meet all the safety requirements with a simultaneous effective procedure. Local one-sided hyperthermia of the synovial membrane and subsequent coagulation of the entire wall thickness due to heat transfer contributes to the elimination of the cavity neoplasm of the popliteal region. With a thickness of 3 mm, the heating mode is satisfactory, under which the exposure time lasts about 200 seconds, and the specific power of the laser radiation in the internal medium of the liquid contents of the Baker cyst is approximately 1. Copyright © 2018 Institute of Computer Science.The work was supported by at the expense of the grant under the “Start-1” program, issued by the Federal State Budgetary Institution “Fund for Assistance to Small Innovative Enterprises in the Scientific and Technical Sphere” (Innovation Promotion Fund)

Влияние природы эмульгатора и концентрации полимера на дисперсность и устойчивость искусственных полимерных суспензий на основе поликарбоната и полиметилметакрилата

Objectives. To create stable artificial polymer suspensions with a positive charge of particles based on polycarbonate and polymethyl methacrylate using cationic surfactants and organosilicon surfactants.Methods. The size of droplets and polymer suspension particles was determined by photon correlation spectroscopy (dynamic light scattering) using a Zetasizer NanoZS laser particle analyzer (Malvern, UK).Results. Domestic cationic surfactants Katamin-AB and Azol-129 were found to be capable of producing stable artificial polycarbonate and polymethyl methacrylate suspensions. Based on the polymer, the optimal surfactant concentration was 6 wt %. The effect of polymer concentration in solution on the stability and particle size of final polymer suspensions was shown. It was determined that the polymer concentration in the solution should not exceed 10%. When obtaining a highly dispersed suspension during dispersion, a higher concentration causes an increase in the viscosity of emulsions. As a result of a synergistic effect formation, we used mixtures of cationic surfactants (Katamin-AB/Azol-138 and Azol-129/Azol-138) to enhance the stability of the final polymer suspensions. The optimal surfactant ratio was 9:1. The total concentration of the mixture is 10 wt %, based on the polymer. Polymer suspensions were stabilized with each of 2:1 mixtures of cationic surfactants Katamin-AB and Azol-129 withan organosilicon surfactant U-851. The total mixture concentration was 9 wt %, based on the polymer.Conclusions. New methods of producing artificial polycarbonate and polymethyl methacrylate suspensions in the presence of domestically produced cationic surfactants, as well cationicorganosilicon surfactants mixtures, were proposed. The colloidal-chemical properties of the obtained polymer suspensions were considered. It was found that using a 2:1 mixture of cationic and organosilicon surfactants produces polymer suspensions that are stable during production and storage.Цели. Создание агрегативно устойчивых искусственных полимерных суспензий с положительным зарядом частиц на основе поликарбоната и полиметилметакрилата с использованием катионных поверхностно-активных веществ (КПАВ), а также их смесей с кремнийорганическим поверхностно-активным веществом (КОПАВ).Методы. Размер капель и частиц полимерных суспензий определяли методом фотонной корреляционной спектроскопии (динамического светорассеяния) с помощью лазерного анализатора частиц Zetasizer NanoZS (Malvern, Великобритания).Результаты. Было установлено, что для получения устойчивых искусственных поликарбонатных и полиметилметакрилатных суспензий могут быть использованы отечественные КПАВ Катамин АБ и Азол-129. Оптимальная концентрация ПАВ составила 6 мас. % в расчете на полимер. Показано влияние концентрации полимера в растворе на устойчивость и размер частиц конечных полимерных суспензий. Определено, что концентрация полимера в растворе не должна превышать 10%. Дальнейшее повышение концентрации приводит к повышению вязкости эмульсий при получении высокодисперсной суспензии в процессе диспергирования. Использованы смеси КПАВ Катамин АБ/Азол-138 и Азол-129/Азол-138 для повышения устойчивости конечных полимерных суспензий за счет образования синергетического эффекта. Оптимальное массовое соотношение ПАВ составило 9:1. Общая концентрация смеси 10 мас. % в расчете на полимер. Получены полимерные суспензии, стабилизированные смесями КПАВ Катамин АБ/КОПАВ U-851 и КПАВ Азол-129/КОПАВ U-851 в соотношении 2:1 каждой смеси в расчете на полимер. Общая концентрация смеси составила 9 мас. % в расчете на полимер.Выводы. Предложены новые способы получения искусственных поликарбонатных и полиметилметакрилатных суспензий, полученных в присутствии КПАВ отечественного производства, а также их смесей и смесей КПАВ с КОПАВ. Рассмотрены коллоидно-химические свойства полученных полимерных суспензий и показано, что при использовании смеси КПАВ и КОПАВ, взятых в объемном соотношении 2:1, образуются устойчивые в процессе получения и хранения полимерные суспензии

Global Symmetries and D-Terms in Supersymmetric Field Theories

We study the role of D-terms in supersymmetry (SUSY) breaking. By carefully analyzing the SUSY multiplets containing various conserved currents in theories with global symmetries, we obtain a number of constraints on the renormalization group flow in supersymmetric field theories. Under broad assumptions, these results imply that there are no SUSY-breaking vacua, not even metastable ones, with parametrically large D-terms. This explains the absence of such D-terms in models of dynamical SUSY-breaking. There is, however, a rich class of calculable models which generate comparable D-terms and F-terms through a variety of non-perturbative effects; these D-terms can be non-abelian. We give several explicit examples of such models, one of which is a new calculable limit of the 3-2 model.Comment: 34 pages, 2 figures; reference added, minor change

A microscopic theory of gauge mediation

We construct models of indirect gauge mediation where the dynamics responsible for breaking supersymmetry simultaneously generates a weakly coupled subsector of messengers. This provides a microscopic realization of messenger gauge mediation where the messenger and hidden sector fields are unified into a single sector. The UV theory is SQCD with massless and massive quarks plus singlets, and at low energies it flows to a weakly coupled quiver gauge theory. One node provides the primary source of supersymmetry breaking, which is then transmitted to the node giving rise to the messenger fields. These models break R-symmetry spontaneously, produce realistic gaugino and sfermion masses, and give a heavy gravitino.Comment: 24 pages, 2 figures, accepted to JHEP for publicatio