Reduction of the Negative Impact on the Environment By Optimizing the Combustion Process in Diesel Engines

The article considers the problem of the negative impact of the exhaust gases of diesel internal combustion engines on the environment and human health. The types of organization of the ignition process and the process of fuel combustion in a diesel engine are considered. The reasons for the occurrence of increased particulate matter in internal combustion engines in exhaust gases are also described. The main factors affecting the delay of ignition are given. The main stages of soot formation in diesel internal combustion engines are described. The influence of temperature distribution in the jets of injected fuel and the dependence of emissions on the coefficient of excess air are considered. As a result, the main conclusions are given on ensuring the reduction of solid particles in the exhaust gases of diesel engines by optimizing the combustion process

The Peculiarities of the Influence of the Finite Sizes of a Detail on the Distribution of the Surface Layer Micro-hardness

It was found that under wave deformation hardening the state of a generated wave, depending on the geometry of the workpieces, has a significant impact on the surface layer micro-hardness distribution

ELECTIVE COURSE AT THE THEORETICAL DEPARTMENT AS A BASIS FOR PROFESSIONAL COMPETENCIES FORMATION OF A PHYSICIAN

Introduction. One of the problems of the higher school is mismatch of activities of the Theoretical and Degree Granting (main) Departments to form the students’ competencies. The use of fundamental knowledge in contents of professional preparation components quite often has formal character. The violation of integrity and continuity of training in higher education institution turns out to be the consequence of it. In medical educational institutions the situation is complicated by the fact that each of numerous clinical departments has its own specifics defining inquiries to the content of the particular theoretical discipline. The aim of the article is justify the need for designing elective courses at theoretical departments in medical universities, which enable future physicians to acquire both the fundamental knowledge and required professional competencies. Methodology and research methods. The framework of the article is based on activity, practice-oriented and competency-based approaches to education. When selecting educational material for elective courses, the foundations of contextual (motivational) approach to education, the method of expert evaluations, the dialectic principles of systemacity and variability of the educational material content, unity of integration and differentiation of fundamental knowledge were used. Results and scientific novelty. The author describes the experience of designing elective courses for students of various specialties and training programs at the Department of Histology, Cytology and Embryology of the Donetsk National Medical University named after M. Gorky. Since there are currently no general programs for Histology elective courses within the competency-based concept of education, their designing is a topical issue of Didactics. The principles of the content selection for such courses are formulated in accordance with their main purpose – cross-disciplinary integration of fundamental and applied knowledge. Practical significance. The publication findings could be useful for managerial personnel and lecturers of medical universities when designing integrated courses the content of which is interdisciplinary.Введение. Одной из проблем высшей школы является рассогласованность деятельности теоретических и выпускающих (профилирующих) кафедр по формированию компетенций студентов. Использование фундаментальных знаний в содержании профессиональной компоненты подготовки нередко носит формальный характер. Следствием этого становится нарушение целостности и преемственности обучения в вузе. В медицинских образовательных учреждениях ситуация осложняется тем, что у каждой из многочисленных клинических кафедр есть своя специфика, определяющая запросы к содержанию конкретной теоретической дисциплины. Цель статьи – обосновать необходимость разработки на теоретических кафедрах медицинского вуза вариативных курсов, обеспечивающих освоение будущими врачами как базисных, фундаментальных знаний, так и требующихся профессиональных компетенций. Методология и методы. Работа осуществлялась с опорой на деятельностный, практико-ориентированный и компетентностный подходы к образованию. При отборе учебного материала для вариативных курсов использовались положения контекстного (мотивационного) подхода к обучению, метод экспертных оценок, диалектические принципы системности и вариативности содержания учебного материала, единства интеграции и дифференциации фундаментальных знаний. Результаты и научная новизна. Описан опыт кафедры гистологии, цитологии и эмбриологии Донецкого национального медицинского университета по проектированию вариативных курсов для студентов разных специализаций и направлений подготовки. Поскольку в настоящее время в рамках компетентностной концепции образования не существует стандартных программ вариативных курсов по гистологии, их конструирование является актуальной проблемой дидактики. Сформулированы принципы отбора содержания таких курсов, предназначение которых состоит в междисциплинарной интеграции фундаментальных и прикладных знаний. Практическая значимость. Материалы публикации могут быть полезны руководителям и преподавателям кафедр медицинских вузов при разработке интегрированных курсов, содержание которых находится на стыке фундаментальных и прикладных дисциплин

Spectroscopic characterization of charge carrier anisotropic motion in twisted few-layer graphene

Graphene, a layer of carbon atoms in a honeycomb lattice, captures enormous interest as probably the most promising component of future electronics thanks to its mechanical robustness, flexibility, and unique charge carrier quasiparticles propagating like massless high energy Dirac fermions. If several graphene layers form a stack, the interaction between them is, on the one hand, weak, allowing realization of various registries between the layers and, on the other hand, strong enough for a wide range tuning of the electronic properties. Here we grow few layer graphene with various number of layers and twist configurations and address the electronic properties of individual atomic layers in single microscopic domains using angle-resolved photoelectron spectromicroscopy. The dependence of the interlayer coupling on the twist angle is analyzed and, in the domains with tri-layers and more, if different rotations are present, the electrons in weaker coupled adjacent layers are shown to have different properties manifested by coexisting van Hove singularities, moir\ue9 superlattices with corresponding superlattice Dirac points, and charge carrier group velocity renormalizations. Moreover, pronounced anisotropy in the charge carrier motion, opening a possibility to transform strongly coupled graphene bilayers into quasi one-dimensional conductors, is observed

Assembling nanostructures from DNA using a composite nanotweezers with a shape memory effect

The article demonstrates a technique for fabricating a structure with the inclusion of suspended DNA threads and manipulating them using composite nanotweezers with shape memory effect. This technique could be suitable for stretching of nanothin DNA-like conductive threads and for measuring their electrical conductivity, including the I-V characteristic directly in the electron microscope chamber, where the nanotweezers provide a two-sided clamping of the DNA tip, giving a stable nanocontact to the DNA bundle. Such contact, as a part of 1D nanostructure, is more reliable during manipulations with nanothreads than traditional measurements when a nanothread is touched by a thin needle, for example, in a scanning tunnel microscope.Comment: To be presented on IEEE 3M-NANO 201

Property control methods of diamond-like silicon-carbon films for micro- and nanoelectronics

Possible methods for controlling the properties of amorphous diamond-like silicon-carbon films are considered: physical or structural modification, chemical modification, and physical-chemical modification. It is shown that the method of physical modification allows controlling in a wide range the properties of diamondlike silicon-carbon films (electrophysical, mechanical properties and surface morphology) without changing the chemical composition of the material. Chemical modification was carried out by introducing transition metal into diamond-like silicon-carbon films. The dependences of the phase composition, electrophysical and mechanical properties on the content and type of metal are analyzed. The method of physical-chemical modification is considered, when the introduced impurity changes not only the chemical composition, but also the structure of the material