Symmetry breakings in dual-core systems with double-spot localization of nonlinearity

We introduce a dual-core system with double symmetry, one between the cores, and one along each core, imposed by the spatial modulation of local nonlinearity in the form of two tightly localized spots, which may be approximated by a pair of ideal delta-functions. The analysis aims to investigate effects of spontaneous symmetry breaking in such systems. Stationary one-dimensional modes are constructed in an implicit analytical form. These solutions include symmetric ones, as well as modes with spontaneously broken inter-core and along-the-cores symmetries. Solutions featuring the simultaneous (double) breaking of both symmetries are produced too. In the model with the ideal delta-functions, all species of the asymmetric modes are found to be unstable. However, numerical consideration of a two dimensional extension of the system, which includes symmetric cores with a nonzero transverse thickness, and the nonlinearity-localization spots of a small finite size, produces stable asymmetric modes of all the types, realizing the separate breaking of each symmetry, and states featuring simultaneous (double) breaking of both symmetries.Comment: 14 pages, 8 figure

Technological and technical solutions to the problem of soil compaction and depletion in the system of precision farming in the conditions of Northern Kazakhstan

In this work have considered the problems of soil compaction and the main nutrition ofplant in the system ofprecision farming in the conditions of the main grain-sowing regions of Northern Kazakhstan. The specific examples show the condition of the soil, the level of their supply with nitrogen and phosphorus. Technological and technical solutions are proposed for the differentiated use of basic doses of mineral fertilizers and soil decompression. В данной работе рассмотрены проблемы уплотнения почвы и основного питания растений в системе точного земледелия в условиях основных зерносеющих районов Северного Казахстана. Конкретные примеры показывают состояние почв, уровень их обеспеченности азотом и фосфором. Предложены технологические и технические решения для дифференцированного использования основных доз минеральных удобрений и декомпрессии почвы

Влияние распределения нагрузки по осям машинно-тракторных агрегатов на глубину следа

It is defined that while doing some agricultural operations the area covered by the machine-tractor aggregates wheels exceeds the area of the field. (Purpose of research) The regularity of repeated accumulation of the soil puddling and the influence of the specifity of axle load distribution of machine-tractor aggregates on the dip of the wheel-track is justified. (Materials and methods) The mathematical apparatus to describe the influence of the effects connected with the soil particles reposition while the repeated loading is developed. The over consolidated soil creates some raised resistance while the following tillage which results in increased fuel consumption and lost productivity of machine-tractor aggregates. The modified soilstructure is difficult to be restored entirely. As a result the intensive worked tilth top soil degrades with time which creates the ecosystem disbalance of cultivated land. The laboratory experiments of the soil features influence and the specifity of wheel loading on the dip of the wheel-track are performed. The regularity of repeated puddling accumulation being subject to Bolstman correlation which links the process entropy and the probability of this state (statistical interpretation of the principle of entropy increase) is set. (Results and discussion) The dependences to determine the deformation of soil with various physical and mechanical properties under different drive system loading conditions of machine-tractor aggregates are obtained. The influence of axle load distribution on the dip of the wheel-track is established. The dependence to describe the process of wheel track formation on the sod-podzolic sandy loam soil of low moisture level which corresponds to the empirical data is obtained. The calculations from the dependence obtained are performed. While doing repeated passes the wheel sinkage is provided only by the increase of contact stresses. (Conclusions) The regularity of the soil puddling rise from the deformer while the repeated loading is set. The regularity obtained makes possible to define the soil deformation depending on the different operating conditions and the drive system parameters of machine-tractor aggregates on different types of soil.При выполнении различных сельскохозяйственных операций площадь, покрываемая колесами машинно-тракторных агрегатов (МТА), при движении превышает площадь самого поля. (Цель исследования) Обосновать закономерности накопления повторных осадок почвы и влияние характера распределения нагрузки по осям машинно-тракторных агрегатов на глубину следа колеса. (Материалы и методы) Разработали математический аппарат для описания влияния явлений, связанных с переукладкой частиц почвы при повторных ее нагружениях. Переуплотненные участки почвы создают повышенное сопротивление при последующих ее обработках, что влечет перерасход топлива и снижение производительности МТА. Разрушенная структура почвы полностью не восстанавливается, в результате чего интенсивно обрабатываемый пахотный слой с течением времени деградирует, что ведет к нарушению экологии агроландшафтов. Провели экспериментальные лабораторные исследования влияния свойств почвы и характера нагружения колес на глубину следа. Определили, что закономерности накопленияповторных осадок подчиняются зависимости Больцмана, связывающей энтропию процесса и вероятность данного состояния (статистическая интерпретация второго начала термодинамики). Получили зависимости для определения деформации почвы с разными физико-механическими свойствами при различных режимах нагружения ходовых систем машинно-тракторных агрегатов. Рассчитали, что распределение нагрузки по осям ходовой системы влияет на глубину следа. (Результаты и обсуждение) Вывели зависимость для описания процесса следообразования на дерново-подзолистой супесчаной почве малой влажности (7,1 процента), отвечающую результатам экспериментов. Провели расчеты на основании полученной зависимости, когда осадка колес при повторных проходахосуществляется лишь за счет повышения контактных напряжений. (Выводы) Определили закономерность нарастания осадки почвы от деформатора при повторных нагружениях. Выявили, что полученные закономерности позволяют найти степень деформации почвы в зависимости от различных режимов работы и параметров ходовых систем МТА на различных типах почвогрунт

Нестационарная модель процесса гидратации железобетонного изделия, находящегося в программно-нагреваемой среде

The development of mathematical models for design of the thermal technology equipment intended for accelerated hydration of concrete products is an urgent task of industrial heat power engineering. The introduction of mathematical modeling methods can reduce the time and the resources spent for the development of technological regimes that reduce energy consumption in the production of building structures and, ultimately, in the construction of buildings and structures for various purposes. There is not yet a generally accepted mathematical model of thermal processes occurring in thermal technological installations in the case of accelerated hardening of a three-dimensional concrete object. The purpose of this work is to develop an unsteady model of the concrete hydration process applied to a symmetrical three-dimensional reinforced concrete product at software-controlled heating. By using the numerical finite-volume method in the case of a 0.3 × 0.3 ×0.3 mcube, a three-dimensional feld of hydration in a concrete object at a given operation mode of a heater is calculated. The following heating mode was used: “heating–maintaining at a constant temperature–cooling”. The dependences of a temperature difference between reinforced and non-reinforced cubic products on the hardening time at the corresponding space points in the direction from the surface to the center of the product have been obtained. By the example of the numerical simulation results, it is shown that the evolution of the hydration degree at these points during the hardening of non-reinforced concrete differs from the hardening of reinforced concrete. The time dependences of heat treatment of a rate of temperature change and the hydration coefficient at the selected points of a product are presented. The obtained results are analyzed.Разработка математических моделей, призванных обеспечить расчет и проектирование энерготехнологического оборудования, предназначенного для осуществления ускоренной гидратации бетонных изделий, является актуальной задачей промышленной теплоэнергетики. Внедрение методов математического моделирования позволяет сократить затраты времени и ресурсов на разработку технологических режимов, обеспечивающих снижение энергопотребления при производстве строительных конструкций и возведении зданий и сооружений различного назначения. Несмотря на значительное число опубликованных результатов исследований, посвященных данной проблеме, не существует общепринятой математической модели теплотехнических процессов, протекающих в теплоэнергетических установках при ускоренном твердении трехмерного бетонного изделия. Цель настоящей работы состоит в разработке нестационарной модели процесса гидратации бетона применительно к симметричному трехмерному изделию, помещенному в программно-управляемую среду обогрева, параметры которой задаются выбранным режимом работы теплоэнергетической установки для ускоренной гидратации. численным методом конечных объемов на примере куба размером 0,3 × 0,3 × 0,3 м выполнены расчеты эволюции трехмерного поля гидратации в бетонном теле при режиме работы нагревателя вида «нагрев–изотермическая выдержка–охлаждение» и получены зависимости разности температур армированного и неармированного кубического изделия от времени твердения в соответственных точках пространства по направлению от поверхности к центру изделия. На примере результатов моделирования показано, что эволюция степени гидратации в указанных точках различается при твердении бетона с арматурой и без арматуры. Представлены скорости изменения температуры и коэффициента гидратации от времени в выделенных точках изделия и проведен анализ полученных результатов

Self-confined light waves in nematic liquid crystals

The study of light beams propagating in the nonlinear, dispersive, birefringent and nonlocal medium of nematic liquid crystals has attracted widespread interest in the last twenty years or so. We review hereby the underlying physics, theoretical modelling and numerical approximations for nonlinear beam propagation in planar cells filled with nematic liquid crystals, including bright and dark solitary waves, as well as optical vortices. The pertinent governing equations consist of a nonlinear Schrödinger-type equation for the light beam and an elliptic equation for the medium response. Since the nonlinear and coupled nature of this system presents difficulties in terms of finding exact solutions, we outline the various approaches used to resolve them, pinpointing the good agreement obtained with numerical solutions and experimental results. Measurement and material details complement the theoretical narration to underline the power of the modelling

Factors interacting with bacterial RNA polymerase and their effect on the regulation of transcription initiation

(ENGLISH) The bacterial cell needs to regulate its gene expression in response to changing environmental conditions. RNA polymerase (RNAP) is the pivotal enzyme of this process and its activity is controlled by a number of auxiliary factors. Here I focus on RNAP-associating factors involved in regulation of transcription in G+ bacteria: factors, initiating nucleoside triphosphates (iNTPs), HelD, δ and small RNA Ms1. The main emphasis is on σ factors from Bacillus subtilis. σ factors allow RNAP to specifically recognize promoter DNA. In my first project I set up in vitro transcription systems with purified alternative σ factors, σB , σD , σH , σI from B. subtilis. Using these systems, I studied the effect of initiating NTP concentration ([iNTP]) on transcription initiation. I showed that promoters of alternative factors are often regulated by [iNTP]. In the next project I comprehensively characterized one of the least explored alternative factors from B. subtilis, I . I identified ~130 genes affected by I , though only 16 of them were directly affected. Moreover, I discovered that I is involved in iron metabolism. Finally, I showed that I binding requires not only the conserved -35 and -10 hexamers, but also extended -35 and -10 elements located in the spacer region. In collaboration with..

Růst Mycobacterium smegmatis na agarovém médiu a agarovém médiu pokrytém celofánovou folií - morfologická a proteomová studie

Biofilm formation is one of the most common bacterial survival strategies. Majority of bacterial species are able to form these three-dimensional structures, including pathogens like Mycobacterium tuberculosis. Representatives of Mycobacterium genus widely occur in the nature, although they can cause serious problems when they appear in medical equipment and artificial replacements of the human body. Non-pathogenic Mycobacterium smegmatis mc2 155 was used as a model organism in our experiments. We investigated morphology of the three- and six-day-old colonies (in fact biofilms) on agar and agar covered with cellophane using Stereo microscope and Scanning Electron Microscope. We found that a type of surface as well as a carbon source has a great influence on the morphology of the M. smegmatis colonies. We isolated proteomes from the agar and cellophane cultures and from planktonic culture. Two-dimensional electrophoresis was used as the main proteomic method. Proteomic data were analyzed using PDQuest software. Then the sets of proteins detected by qualitative and quantitative analyses were compared using Venn diagrams. As a result, we recognized 7 unique proteins that might be specific for recognition and adhesion of bacteria to the cellophane, no unique protein in agar proteome and 46 unique..

Improving the quality of requirements artifacts in agile projects

The main aim of the research is development of a framework that can be used by agile practitioners to improve the quality of requirements artifacts. In order to achieve the thesis goal a thorough literature review has been performed. The key concepts and detailed quality criteria checks list have been elaborated within the focus group discussion and then validated with the help of the online survey. The framework has been applied on the real project and reviewed for the automation possibilities. The main thesis output is the framework that contains the agile quality criteria list elaborated with exact checks that have to be performed and suggested quality check gateways for performing these checks. The framework also suggests the prioritisation of the quality criteria based on the most frequent and important problems in agile teams.The main aim of the research is development of a framework that can be used by agile practitioners to improve the quality of requirements artifacts. In order to achieve the thesis goal a thorough literature review has been performed. The key concepts and detailed quality criteria checks list have been elaborated within the focus group discussion and then validated with the help of the online survey. The framework has been applied on the real project and reviewed for the automation possibilities. The main thesis output is the framework that contains the agile quality criteria list elaborated with exact checks that have to be performed and suggested quality check gateways for performing these checks. The framework also suggests the prioritisation of the quality criteria based on the most frequent and important problems in agile teams

Quantitative Phase Imaging of Spreading Fibroblasts Identifies the Role of Focal Adhesion Kinase in the Stabilization of the Cell Rear

Cells attaching to the extracellular matrix spontaneously acquire front–rear polarity. This self-organization process comprises spatial activation of polarity signaling networks and the establishment of a protruding cell front and a non-protruding cell rear. Cell polarization also involves the reorganization of cell mass, notably the nucleus that is positioned at the cell rear. It remains unclear, however, how these processes are regulated. Here, using coherence-controlled holographic microscopy (CCHM) for non-invasive live-cell quantitative phase imaging (QPI), we examined the role of the focal adhesion kinase (FAK) and its interacting partner Rack1 in dry mass distribution in spreading Rat2 fibroblasts. We found that FAK-depleted cells adopt an elongated, bipolar phenotype with a high central body mass that gradually decreases toward the ends of the elongated processes. Further characterization of spreading cells showed that FAK-depleted cells are incapable of forming a stable rear; rather, they form two distally positioned protruding regions. Continuous protrusions at opposite sides results in an elongated cell shape. In contrast, Rack1-depleted cells are round and large with the cell mass sharply dropping from the nuclear area towards the basal side. We propose that FAK and Rack1 act differently yet coordinately to establish front–rear polarity in spreading cells

Electrodeionization

Elektrodeionizace je moderní elektromembránový separační proces používaný v chemickém inženýrství. Proces je založen na iontově výměnných membránách a na působení stejnosměrného elektrického pole na roztoky elektrolytů. Při tom dochází k zachycení iontů elektrolytu ionexem a jejich migraci přes kationtově a aniontově výměnné membrány vlivem gradientu elektrického potenciálu. Elektrodeionizace se používá převážně pro přípravu tzv. ultračisté vody pro farmaceutický, elektronický nebo chemický průmysl a pro elektrárny.Electrodeionization is a modern electromembrane separation process in chemical technology. This process uses ion-exchange membranes and ionexes placed in an electric field (DC), which acts on electrolyte solutions. Ions of the electrolyte are caught by ionexes and transported through the ion-exchange membranes by the electrochemical potential as a driving force. Electrodeionization is used for preparing of ultrapure water in pharmaceutical, electronical and chemical industry and for purification of water in power plants.Ústav environmentálního a chemického inženýrstvíJaké nejkoncentrovanější roztoky se uvedenou metodou elektrodeionizace mohou zpracovávat? Jaká je zhruba účinnost metody? Porovnejte elektrodeionizaci a elektrodialýzu, uveďte klady a zápory obou metod. Uveďte místa užívaných aplikací elektrodeionizace a elektrodialýzy, zejména v ČR. Student uspokojivě zodpověděl položené dotazy