Surface plasmon peak intensity dependence on the oxygen coverage at metal surfaces

The dependence of the surface plasmon peak intensity on a submonolayer coverage of oxygen in the reflection electron energy loss spectra has been investigated for non-monocrystalline aluminium, magnesium, and indium surfaces. It will be shown that the decrease of the surface plasmon peaks can be related to a modification of the surface plasmons dispersion relation. A simple model for this modification introduced by changes of the surface electron density profile is proposed. Parameters of this model will be determined from experimental data

Molecular Dynamics Simulations of Radiation Damage in Ti-Al based Structural Intermetallics

Molecular dynamics simulations were conducted to explore primary damage formation in collision cascades i

Continuum and discrete models of dislocation pile-ups. I Pile-up at a lock

A mathematical methodology for analysing pile-ups of large numbers of dislocations is described. As an example, the pile-up of n identical screw or edge dislocations in a single slip pane under the action of an external force in the direction of a locked dislocation in that plane is considered. As $n \rightarrow \infty$ there is a well-known formula for the number density of the dislocations, but this density is singular at the lock and it cannot predict the stress field there or the force on the lock. This poses the interesting analytical and numerical problem of matching a local discrete model near the lock to the continuum model further away

Prediction of Mechanical Behaviour in Ni-Base Superalloys Using the Phase Field Model of Dislocations

The "Phase-Field Model of Dislocations" (PFMD) was used to simulate shearing of gamma-prime precipitate arrays in single crystal turbine blade superalloys. The focus of the work has been on the cutting of the L12 ordered precipitates by a{111} dislocation ribbons during Primary Creep. The Phase Field Model presented incorporates specially developed Generalised Stacking Fault Energy (γ-surface) data obtained from atomistic simulations. The topography of this surface determines the shearing mechanisms observed in the model. The merit of the new γ-surface, is that it accounts for the formation of extrinsic stacking faults, making the model more relevant to creep deformation of superalloys at elevated temperatures

The role of distance education in the modern educational space

The article reveals the role of distance education in the modern educational space. The purpose of the article is to clarify the role of distance education in the modern educational space. The research is based on methodological, theoretical and practical levels. The development of distance education is considered from the following directions: online courses, the results of analytical reviews are shown, the possibility of using distance learning in institutions of higher education as a separate approach to learning or together with traditional forms of the educational process; distance universities. The possibilities of distance education, which are now offered by institutions of higher education, are proven, the forms of distance classes are considered, and their diversity is shown, examples of obtaining such education in different countries of the world are given. Features of distance universities are listed: simplified admission to the university; the availability of education is limited only by knowledge of the relevant language, technical capabilities, and funds; exams at leading distance universities are mostly conducted face-to-face, which prevents fraud, although there are additional costs for students. The most common types of distance education, which are the most essential in the educational space of society, are considered

Mikrostrukurelle Mechanismen der Strahlenversprödung

Gegenstand des Vorhabens im Rahmen der WTZ mit Russland ist die Versprödung des Reaktordruckbehälters infolge der Strahlenbelastung mit schnellen Neutronen im kernnahen Bereich. Um den Einfluss von bestrahlungsinduzierten Gitterdefekten auf die mechanischen Eigenschaften zu ermitteln, wurden analytische Berechnungen zum Einfluss von Hindernissen auf die Beweglichkeit von Versetzungen und damit auf die Ausbildung einer plastischen Zone an der Rissspitze durchgeführt. Es wird demonstriert, dass sich die an der Rissspitze entstehenden Versetzungen an dem Hindernis (bestrahlungsinduzierte Punktdefekte) aufstauen. In Abhängigkeit der Rissbelastung KI und der Entfernung des Hindernisses von der Rissspitze werden die Versetzungsdichte und das durch den Versetzungsstau verursachte Spannungsfeld berechnet. Mit Hilfe von Experimenten zur Neutronenkleinwinkelstreuung (SANS - small angle neutron scattering) an verschiedenen WWER-Stählen und Modelllegierungen wurden Größenverteilungen und die Volumenanteile der strahleninduzierten Defekte für verschiedene Bestrahlungszustände (Fluenzen, Bestrahlungstemperaturen) ermittelt. Es wurde gezeigt, dass sich die strahleninduzierte Werkstoffschädigung durch Wärmebehandlung weitgehend wieder ausheilen lässt. Nach der thermischen Ausheilung ist der Werkstoff bei erneuter Bestrahlung weniger anfällig für strahleninduzierte Defekte. Die Ergebnisse der SANS-Untersuchungen wurden mit der Änderung der mechanischen Eigenschaften (Härte, Streckgrenze und Sprödbruchübergangstemperatur) korreliert. Mit der kinetischen Gitter-Monte-Carlo-Methode wurden numerische Sensitivitätsstudien zum Einfluss des Cu-Gehalts auf die Stabilität von Defekt-Clustern durchgeführt. Die Berechnungen zeigen, dass die Anwesenheit von Cu-Atomen zur Bildung von langlebigen Defekten führt. Dabei werden Leerstellen in Cu/Leerstellen-Cluster eingefangen. Leerstellen in reinem Eisen sind bei Bestrahlungstemperaturen von 270 °C dagegen nicht stabil, die Lebensdauer liegt zwischen 0.01 s und 1 s. Die kritische Cu-Konzentration, ab welcher stabile Defekte entstehen, beträgt ca. 0.1 Masseprozent

Regularising algorithm of parameter identification of electric charge equivalent circuit

A new algorithm of parameter identification of equivalent circuit for electrical charge replacement is suggested. The approach is based on the solution of integral equation of the I type with respect to the function of indicial admittance, by which then determination of replacement circuit parameters is carried out. Application of smoothing splines and original regulating algorithm including kernel setting error of integration equation permits to obtain a stable algorithm of parameter identification. The investigation of algorithm shows high calculating efficiency and sufficient accuracy of parameter identification

Особливості підтримки та розвитку бізнесу в умовах воєнного стану в Україні

Воскобойніков, В. В. Особливості підтримки та розвитку бізнесу в умовах воєнного стану в Україні / Вадим Володимирович Воскобойніков // Захист та дотримання прав громадян органами Національної поліції України в умовах воєнного стану : тези доп. учасників наук.-практ. конф. (м. Вінниця, 7 груд. 2022 р.) / МВС України, Харків. нац. ун-т внутр. справ, Наук. парк «Наука та безпека». – Вінниця : ХНУВС, 2022. – С. 27-29.Наголошено на важливості створення умов для реалізації представниками бізнесу свого підприємницького потенціалу, що набуває особливої значущості під час дії воєнного стану по всій території держави, оскільки це дозволить зберегти економічний потенціал України, створити передумови для виникнення нових робочих місць. У свою чергу це стане якісним фундаментом для післявоєнного відновлення нашої держави та зміцнення потужностей підприємств в умовах галузевої трансформації бізнесу.It was emphasized the importance of creating conditions for business representatives to realize their entrepreneurial potential, which becomes especially significant during the martial law throughout the state, as this will preserve the economic potential of Ukraine and create prerequisites for the creation of new jobs. In turn, this will become a high-quality foundation for the post-war recovery of our state and the strengthening of the capacities of enterprises in the conditions of sectoral transformation of business.Отмечено важность создания условий для реализации представителями бизнеса своего предпринимательского потенциала, что приобретает особую значимость во время действия военного положения по всей территории государства, поскольку это позволит сохранить экономический потенциал Украины, создать предпосылки для возникновения новых рабочих мест. В свою очередь, это станет качественным фундаментом для послевоенного восстановления нашего государства и укрепления мощностей предприятий в условиях отраслевой трансформации бизнеса

Effect of collision cascades on dislocations in tungsten: A molecular dynamics study

Tungsten (W) is the prime candidate material for the divertor and other plasma-facing components in DEMO. The point defects (i.e. vacancies and self-interstitials) produced in collision cascades caused by incident neutrons aggregate into dislocation loops (and voids), which strongly affect the mechanical properties. The point defects also interact with existing microstructural features, and understanding these processes is crucial for modelling the long term microstructural evolution of the material under fusion conditions. In this work, we performed molecular dynamics simulations of cascades interacting with initially straight edge dislocation dipoles. It was found that the residual vacancy number usually exceeds the residual interstitial number for cascades interacting with vacancy type dipoles, but for interstitial type dipoles these are close. We observed that a cascade near a dislocation promotes climb, i.e. it facilitates the movement of point defects along the climb direction. We also observed that the dislocations move easily along the glide direction, and that kinks are formed near the centre of the cascade, which then facilitate the movement of the dipoles. Some dipoles are sheared off by the cascade, and this is dependent on PKA energy, position, direction, and the width of dipole

Current approaches to risk assessment of chronic heart failure after myocardial infarction

In the last decade, there has been an increase in the number of survivors of myocardial infarction (MI). However, the risk of developing chronic heart failure (CHF) remains high in this category of patients. Population aging and comorbidity further contribute to adverse outcomes. Optimization of approaches to identify predictors of postinfarction CHF is an important clinical task of modern medicine. The aim of the investigation is to develop a method to assess the risk of CHF development after MI. Material and Methods. The present analysis included 186 patients who underwent MI from January 2019 to January 2020: 86 patients with signs of CHF above functional class (FC) 2 (NYHA) (mean age 64.3 years) and 100 patients without signs of CHF or with CHF 1 (NYHA) (mean age 62.6 years) by day 30 of MI. A mathematical model of CHF risk after MI was built by factor and correlation analysis methods. Results. A method for assessing CHF risk after a previous MI was developed. The proposed formula is programmed in Excel table processor and includes 5 indicators: presence of atrial fibrillation, Killip class of acute heart failure, triglycerides level, ST-segment elevation of electrocardiogram, left ventricular ejection fraction less than 45 %. The authors’ approach allows long-term personalized monitoring, taking into account the ranked contribution of each factor in a particular patient; it is characterized by high sensitivity, specificity, and accuracy. Conclusion. The present study investigated the factors of formation of postinfarct chronic heart failure syndrome. An original mathematical formula for CHF risk estimation, including routine indices of MI patients, has been proposed. The approach allows personalized management of selected cohorts of patients – with increased and standard risk of postinfarction CHF