Investigation of initiation conditions of relative displacements of the fault-block media units under vibration loading

On the basis of computer modeling by the method of movable cellular automata the theoretical investigation of initiation conditions of relative displacements along the interfaces of complex stressed geological media blocks in the complex intense condition under local vibrating loading has been performed. It is shown, that defining factors at formation of unstable shift on the interblock border of fracture-block geological environments are the relative value of shift stresses and also the frequency of vibrating loading, i. е. time of impulse energy allocation. Low in power, but long-continued loadings on influences on high-voltage borders of section are the most effective in respect to power inputs

Development of a formalism of movable cellular automaton method for numerical modeling of fracture of heterogeneous elastic-plastic materials

A general approach to realization of models of elasticity, plasticity and fracture of heterogeneousmaterials within the framework of particle-based numerical methods is proposed in the paper. It is based onbuilding many-body forces of particle interaction, which provide response of particle ensemble correctlyconforming to the response (including elastic-plastic behavior and fracture) of simulated solids. Implementationof proposed approach within particle-based methods is demonstrated by the example of the movable cellularautomaton (MCA) method, which integrates the possibilities of particle-based discrete element method (DEM)and cellular automaton methods. Emergent advantages of the developed approach to formulation of manybodyinteraction are discussed. Main of them are its applicability to various realizations of the concept ofdiscrete elements and a possibility to realize various rheological models (including elastic-plastic or visco-elasticplastic)and models of fracture to study deformation and fracture of solid-phase materials and media.Capabilities of particle-based modeling of heterogeneous solids are demonstrated by the problem of simulationof deformation and fracture of particle-reinforced metal-ceramic composites

Development of multiscale approach to modeling mechanical response of high-strength intermetallic alloys on the basis of movable cellular automaton method

On the basis of movable cellular automaton method (MCA) was developed a multiscale two-dimensional structural and rheological model of hard-strength intermetallic alloy Ni3Al. In this model, the intermetallic alloy is regarded as multiscale composite system. Developed approach takes into account the properties of grain boundaries, the characteristics of the geometry and internal structure of the grains and their size distribution. Internal grain structure of hard-strength alloy is constructed in the framework of MCA method using the algorithm of Voronoi tessellation. To simulate the processes of deformation and fracture of such complex systems by MCA method the two-dimensional model of elastic-plastic interaction of cellular automata is used. This model is based on the use of many-particle potentials/forces of interaction of cellular automata. An incremental theory of plasticity of isotropic medium with von Mises plasticity criterion was used to model deformation of intermetallic alloy. Radial return algorithm of Wilkins was adopted for this purpose. Twoparameter criterion of Drucker-Prager was used as fracture criterion in proposed model. When modeling of the mechanical response of hard-strength alloy peculiarities of its multiscale internal structure (the presence of subgrains in grains) at lower scales with respect to the considered one was taken into account implicitly using a specially developed multiscale approach. Verification of the developed model is performed by simulation of tests on the uniaxial tension of Ni3Al samples and comparing the simulation results with the experimental data. Comparison of the obtained “theoretical” loading diagrams with experimental data showed good qualitative and quantitative similarity. This indicates the adequacy of the developed model and the possibility of its use to describe the deformation and fracture of such complex heterogeneous systems

Evidence of negative Poisson's ratio in wood from finite element analysis and off-axis compression experiments

© 2017 The microstructure of wood is highly anisotropic, which suggests that this material could exhibit unusual elastic properties. A few studies have suggested the possibility of auxeticity, or negative Poisson's ratio (NPR) in some wood samples. In order to conclusively confirm that wood does show NPR, we have used a combination of geometric modelling, finite element analysis (FEA) and off-axis compression testing. The geometric model indicates that idealised thin-walled wood cell structures should generate NPR of −1, FEA suggests that more realistic cell arrays can attain NPR, to −0.27, and compression tests show that some NPR – to −0.74 – remains in real wood samples. These results could help design “engineered-wood” laminates products with tailored elastic properties

Significance of neutrophil flow cytometry in laboratory monitoring in coronary heart disease

The aim of the work is a comparative assessment of quantitative and functional parameters of blood neutrophils in patients with different forms of ischemic heart disease (IHD). In patients with acute myocardial infarction and IHD disease, the number of neutrophils, the content of myeloperoxidase in them by flow cytometry, the level of markers of myocardial damage in immunochemical tests were determined. An increase in the level of neutrophils, including band forms, with a decrease in the level of intracellular myeloperoxidase was established. These changes were more significant in acute myocardial infarction than in IHD. The correlation of the myeloperoxidase level with troponin concentration is shown. The study of peripheral blood neutrophils by flow cytometry with the determination of intracellular myeloperoxidase can be considered as an additional tool for laboratory diagnosis of ischemic heart disease.Цель работы — сравнительная оценка количественных и функциональных параметров нейтрофилов крови, определенных методом проточной цитометрии, у пациентов с разными формами ИБС. У пациентов с острым инфарктом миокарда и хронической ИБС определяли количество нейтрофилов и содержание в них миелопероксидазы методом проточной цитометрии, а также уровень маркеров повреждения миокарда в сыворотке крови. Установлено повышение уровня нейтрофилов, в том числе молодых форм с одновременным снижением уровня внутриклеточной миелопероксидазы. Эти изменения были более выражены при остром инфаркте миокарда, чем при хронической ИБС. Показана корреляционная связь содержания миелопероксидазы с концентрацией тропонина. Исследование нейтрофилов периферической крови методом проточной цитометрии с определением внутриклеточной миелопероксидазы может рассматриваться в качестве дополнительного инструмента лабораторной диагностики ИБС

Rolling Friction in Loose Media and its Role in Mechanics Problems

Rolling friction between particles is to be set in problems of granular material mechanics alongside with sliding friction. A classical problem of material passive lateral pressure on the retaining wall is submitted as a case in point. 3D method of discrete elements was employed for numerical analysis. Material is a universe of spherical particles with specified size distribution. Viscose-elastic properties of the material and surface friction are included, when choosing contact forces. Particles' resistance to rolling relative to other particles and to the boundary is set into the model. Kinetic patterns of medium deformations are given. It has been proved that rolling friction can significantly affect magnitude and nature of passive lateral pressure on the retaining wall

To the characterization of children's health indicators in the period: kindergarten - school

The purpose of this study was to assess and compare recorded and expert health indexes, as well as to identify social and environmental risk factors. Materials and methods. Examination of 255 children were performed (Mean age - 5 years) in five kindergartens in Ekaterinburg. The integrated health examination involved analysis of results of automated system Aspon (d) and further expert examination by a pediatrician. To characterize air pollution we used the results of the study Nitrogen dioxide pollution by the Land Use Regression. The Analysis of Cross-tabulated Data was used to find statistical relationships. Results. Significant differences in expert health assessments and assessments available in the official kindergarten medical documents were found. Gastrointestinal abnormalities, changes osteo-articular, neurologic syndromes, ENT pathology, cardiovascular abnormalities were priority health deviation. Relationship between nitrogen dioxide concentrations and prevalence of gastroenterology, cardiovascular and ENT pathologies were identified.Целью данного исследования явилась оценка и сопоставление регистрируемых показателей здоровья с экспертными показателями, а также выявление факторов риска социального и экологического характера. Материалы и методы. Обследовано 255 детей (средний возраст 5 лет) в пяти ДОУ г. Екатеринбурга. Проведено комплексное обследование, включающее в себя использование автоматизированной системы АСПОН(д) и дальнейшее экспертное обследование педиатром по системам и органам. Для характеристики загрязнения атмосферного воздуха использовались результаты исследования загрязнения диоксидом азота методом Land Use Regression. Для определения наличия статистических взаимосвязей использовался метод таблиц сопряженности признаков. Результаты. Обнаружены существенные различия экспертных оценок групп здоровья и оценок, имеющихся в официальных медицинских документах ДОУ. При этом приоритетными были гастроэнтерологические отклонения, изменения костно-суставной системы, неврологические синдромы, ЛОР патологии, сердечнососудистые отклонения. Выявлены существенные взаимосвязи уровня загрязнения воздуха диоксидом азота и распространенностью гастроэнтерологической, сердечнососудистой и ЛОР патологий

The role of practical classes in the formation of professional competence of students of medical faculty

The article is devoted to the problem of formation of professional competencies of medical university students in practical classes.Статья посвящена проблеме формирования профессиональных компетенций студентов медицинского университета на практических занятиях