Pulsatile non-newtonian blood flow in image-based models of carotid bifurcation

Present hemodynamical study is motivated by the ongoing clinical research at the University Hospital in Pilsen, Czech Republic. On the basis of provided CT scans, several carotid artery models were reconstructed and used for this numerical study of pulsatile blood flow. The blood is modelled as a shear-dependent incompressible fluid, motion of which is described by the non-linear system of Navier-Stokes equations coupled with the Carreau-Yasuda model. The mathematical model is solved using in-house software based on the principle of the SIMPLE algorithm and cell-centred finite volume method (FVM) formulated for hybrid unstructured tetrahedral grids. The discussion of obtained numerical results is performed with special emphasis placed on the analysis of velocity field and distribution of main hemodynamic factors such as cycle-averaged WSS and oscillatory shear index (OSI) in areas prone to atherosclerosis

The constitutional principle of proportionality in foreign and Russian law: a theoretical and practical analysis

O artigo é dedicado a um estudo jurídico comparativo do princípio europeu da proporcionalidade e do método americano de ponderar interesses, suas origens, características comuns e distintivas, fundamentos socioculturais e históricos, a aplicação do princípio da proporcionalidade na ordem jurídica russa. Historicamente, as origens (raízes) do princípio europeu da proporcionalidade remontam à doutrina administrativa-jurídica alemã, e o método americano de ponderação como princípio inicial está associado ao direito privado e só mais tarde foi estendido à esfera do direito público. O artigo avalia o impacto desses princípios na doutrina russa e na prática de aplicação da lei.Objetivo: O objetivo principal do artigo é identificar as características gerais e distintivas do princípio europeu de proporcionalidade e o método americano de equilibrar interesses, a fim de compreender, com base nisso, o modelo jurídico russo para garantir o equilíbrio de interesses públicos e privados.Tarefas: explorar os fundamentos históricos, socioculturais e doutrinários da gênese do princípio europeu da proporcionalidade e do método americano de ponderar interesses; identificar características comuns e especiais características desses métodos; mostrar a influência desses métodos na doutrina russa e na prática da aplicação da lei; comparar o princípio russo de equilíbrio entre interesses públicos e privados com o princípio europeu de proporcionalidade; formular recomendações e sugestões para melhorar as práticas de aplicação da lei na Rússia.Métodos: histórico e jurídico, lógico, formal e jurídico, sistêmico e estrutural, método de pesquisa jurídica intersetorial, método de análise de sistemas.Discussão: o princípio europeu da proporcionalidade e o método americano de ponderar interesses, embora não pertençam a novos fenômenos do pensamento jurídico, no entanto, devido à sua importância fundamental, tanto nos níveis constitucionais quanto em outros setores do desenvolvimento do direito, estão constantemente no centro do campo de visão do pensamento jurídico. no exterior, bem como na Rússia. O surgimento de várias abordagens para entender a provisão legal da balança de interesses privados e públicos está causando discussões animadas, às vezes bastante acentuadas, no campo científico. O artigo enfoca as características históricas, socioculturais, políticas e legais do desenvolvimento do princípio europeu da proporcionalidade e o método americano de equilibrar interesses, o que leva a uma interação e convergência próximas, bem como a necessidade de sua pesquisa científica conjunta, o que pode dar um efeito teórico e prático significativo.Conclusão: o artigo afirma que as características distintivas do princípio europeu da proporcionalidade e do método americano de ponderação de interesses não são de natureza paradigmática essencial, o que nos permite concluir que, neste caso, não há fundamento para uma oposição fundamental entre si dos modelos construtivos acima mencionados como métodos de compreensão jurídica. realidade, bem como meios legais para garantir um equilíbrio de interesses públicos e privados. O desenvolvimento do princípio europeu da proporcionalidade tem um impacto significativo na formação do pensamento e das práticas políticas e jurídicas russas no campo da interação entre direito privado e público, garantindo uma combinação orgânica de interesses privados e públicos, o que se reflete na posição jurídica formulada pelo Tribunal Constitucional da Federação da Rússia sobre o princípio de garantir proporcionalidade. observância, equilíbrio de interesses privados e públicos na implementação da regulamentação legal das relações públicas.The article is devoted to a comparative legal study of the European principle of proportionality and the American method of weighing interests, their origins, common and distinctive features, socio-cultural and historical foundations, the application of the principle of proportionality in the Russian legal order. Historically, the origins (roots) of the European principle of proportionality go back to the German administrative-legal doctrine, and the American method of weighing as an initial principle is associated with private law and only later was extended to the public law sphere. The article assesses the impact of these principles on the Russian legal doctrine and law enforcement practice.Purpose: The main purpose of the article is to identify the general and distinctive features of the European principle of proportionality and the American method of balancing interests in order to comprehend on this basis the Russian legal model for ensuring the balance of private and public interests. Tasks: to explore the historical, socio-cultural, doctrinal foundations of the genesis of the European principle of proportionality and the American method of weighing interests; to identify the common and special features characteristic of these methods; to show the influence of these methods on Russian doctrine and law enforcement practice; compare the Russian principle of balance between private and public interests with the European principle of proportionality; formulate recommendations and suggestions for improving Russian law enforcement practice.Methods: historical and legal, logical, formal and legal, systemic and structural, method of interdisciplinary legal research, method of system analysis.Discussion: the European principle of proportionality and the American method of weighing interests, although they do not belong to new phenomena of legal thought, nevertheless, due to their fundamental importance both at the constitutional and other sectoral levels of development of law, are constantly in the center of the field of vision of legal thought abroad, as well as in Russia. The emergence of various approaches to understanding the legal provision of the balance of private and public interests is causing lively, sometimes quite sharp, discussions in the scientific field. The article focuses on the historical, socio-cultural, political and legal features of the development of the European principle of proportionality and the American method of balancing interests, which leads to both close interaction and convergence, as well as the need for their joint scientific research, which can give a significant theoretical and practical effect.Conclusion: the article states that the distinctive features of the European principle of proportionality and the American method of weighing interests are not of an essential, paradigmatic nature, which allows us to conclude that in this case there are no grounds for a fundamental opposition to each other of the above-named constructive models as methods of understanding legal reality, as well as legal means of ensuring a balance of private and public interests. The development of the European principle of proportionality has a significant impact and impact on the formation of Russian political and legal thought and practice in the field of interaction between private and public law, ensuring an organic combination of private and public interests, which is reflected in the legal position formulated by the Constitutional Court of the Russian Federation concerning the principle of ensuring proportional observance, balance of private and public interests in the implementation of legal regulation of public relations

Study of the Structure and Mechanical Properties of PSZ (Partially Stabilized Zirconia) after Heat Treatment at 1600 ˚C

The phase composition and twin structure of PSZ crystals after heat treatment at 1600 ˚C have been studied in relation to the content of the stabilizing impurity (Y2O3) by X-ray diffraction and transmission electron microscopy. The measurement of both hardness and fracture toughness by microindentation has been carried out. Studies have shown that crystals of PSZ obtained by directional solidification of the melt consist of two tetragonal phases (t and t’), with varying degrees of tetragonality. The yttrium-enriched phase t’ is ‘‘untransformable’’ in contrast to the t phase, with a lower content of yttrium, which, under the influence of mechanical stress, undergoes a martensitic transition to the monoclinic form. Increasing the stabilizing impurity concentration leads to an increase in the volume fraction of the ‘‘untransformable’’ phase. Increasing the concentration of Y2O3 also affects the form and dispersion of the twin domains. In this work it is shown that the quantity of hardening (fracture toughness) is proportional to the content of the transformable t phase. This work was supported by grants from the company "OPTEC" When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3540

Bulk Nanocrystalline Thermoelectrics Based on Bi-Sb-Te Solid Solution

A nanopowder from p-Bi-Sb-Te with particles ~ 10 nm were fabricated by the ball milling using different technological modes. Cold and hot pressing at different conditions and also SPS process were used for consolidation of the powder into a bulk nanostructure and nanocomposites. The main factors allowing slowing-down of the growth of nanograins as a result of recrystallization are the reduction of the temperature and of the duration of the pressing, the increase of the pressure, as well as addition of small value additives (like MoS2, thermally expanded graphite or fullerenes). It was reached the thermoelectric figure of merit ZT=1.22 (at 360 K) in the bulk nanostructure Bi0,4Sb1,6Te3 fabricated by SPS method. Some mechanisms of the improvement of the thermoelectric efficiency in bulk nanocrystalline semiconductors based on BixSb2-xTe3 are studied theoretically. The reduction of nanograin size can lead to improvement of the thermoelectric figure of merit. The theoretical dependence of the electric and heat conductivities and the thermoelectric power as the function of nanograins size in BixSb2-xTe3 bulk nanostructure are quite accurately correlates with the experimental data.Comment: 35 pages, 24 figures, 4 tables, 52 reference

Comparison of Lagrangian-Eulerian and Eulerian-Eulerian Approaches for Particle Laden Free Surface Flow by Means of Lattice Boltzmann Method

The aim of this study is a comparison of Lagrangian-Eulerian and Eulerian-Eulerian numerical approach for the simulation of fluid-particles interaction. Within the study the immersed particles are restricted to have spherical shapes and are equal or smaller than the resolution of the computational mesh. The interaction between fluid and particles is performed using the immersed boundary method and the free surface flow of an incompressible fluid is simulated using the lattice Boltzmann method. Both approaches are compared within two test problems. Firstly, the swarm of particles falling in the fluid, and secondly, casting of the fluid with dispersed particles into a mold. Both tests showed good qualitative and quantitative agreement of mentioned approaches

The Influence of Stabilizing Impurities and Annealing on the Structure and Mechanical Properties of Partially Stabilized Zirconia

The phase composition and evolution of the twin structure of PSZ crystals, depending of the concentration stabilizing impurities have been investigated by X-ray diffraction and transmission electron microscopy. The measurements of hardness and fracture toughness by microindentation have been carried out. In work is shown that the high mechanical characteristics of PSZ crystals are related to features of their phase composition and structure, namely the degree of tetragonality the phase and the presence of domains ranging in size from tens to hundreds of nanometers. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3507

Study of gas hazard pattern in underground workings after blasting

Determining the sources of hazardous and toxic substances released into mine air, their gas composition, as well as providing each such source of pollution with the required amount of fresh air are important issues in terms of ensuring normal healthy and safe working conditions for miners. This paper studies blasting as one of the most dangerous sources of mine air pollution. The study was carried out for a long dead-end exploration working, and a development (preparatory) working of a copper-nickel mine. In accordance with the federal rules and regulations (FNiP), a number of requirements, including monitoring of gas hazard at a face, is applied to blasting operations. The study examined the behavior of gas-air mixture in dead-end mine workings after blasting. The findings are based on the experimental data obtained in the conditions of two dead-end workings at an operating coppernickel mine. A technique for the experimental studies of gas release after blasting in a dead-end working was developed. The main technical characteristics of the instruments involved in the in-situ measurements are given. Time dependences of the concentrations of toxic gases after blasting at the blasted working mouth, at the return ventilation current, and near a booster were established. In order to assess the reliability of the data obtained, the volume of released carbon oxides was calculated based on the data of gas analyzers and chemical reactions of explosives decomposition during detonation, depending on the types and weights of the explosives. A model of gas-air mixture transfer was described, constructed, and calibrated allowing for longitudinal dispersion. The Voronin model was used to simulate the gradual removal of toxic gases from the working face and solving the problem of boundary conditions. Based on experimental data, the coefficients of longitudinal dispersion, ventilation efficiency, and volume concentration of the considered gas admixture in the mixing zone at initial time were determined for a long dead-end mine working. The constructed gas-dynamic model and longitudinal dispersion coefficients obtained as a result of the analysis enabled the time required for long dead-end mine workings ventilation to be analysed and estimated. Based on the model, the algorithm for calculating the velocity of spreading the combustion products in a mine ventilation network in emergency situations is being improved. The value of longitudinal dispersion coefficient for different operating conditions is also being refined. Based on the gas distribution simulation within the interval of 1,500 m from a working face, the time required for the ventilation of a dead-end mine working was determined

Синтез робастной цифровой системы стабилизации микроспутника

Розглянуто питання синтезу цифрової системи стабілізації космічного апарату в орбітальній системі координат з врахуванням взаємозалежності його повздовжнього та бокового рухів. Синтез здійснено з умови мінімізації структурованого сингулярного значення системи. Показано, що застосування білінійного перетворення спеціального виду дозволяє отримати високу якість перехідних процесів в системі.The question of synthesis of digital system of stabilization of a space vehicle in orbital system of coordinates is considered in view of interdependence of his longitudinal and lateral movements. Synthesis is carried out from a condition of minimization structured singular values of system. It is shown, that application of bilinear transformation of a special kind allows to receive high quality of transients in system.Рассмотрен вопрос синтеза цифровой системы стабилизации космического аппарата в орбитальной системе координат с учетом взаимозависимости его продольного и бокового движений. Синтез осуществлен из условия минимизации структурированного сингулярного значения системы. Показано, что применение билинейного преобразования специального вида позволяет получить высокое качество переходных процессов в системе