Effect of Heat Input Pulse on the Structure and Properties of Welded Joints of Steels Ferritic-Pearlitic Class, Operating Under Low-Frequency Temperature-Force Loading

We have investigated the influence of the modes of adaptive pulse-arc welding and surfacing on the structure and physical-mechanical properties of welded joints of steel 09Mn2Si and the surfaced composition of this steel coated with modified powder material of chromium carbide with the submicrocrystalline structure. It is shown that the pulsed mode of welding and surfacing can improve the homogeneity of the structure of the welded joint of steel and surfaced coating and reduce the grain size of metals in both of them. Structural changes lead to the increase in ductility and toughness of the weld metal

Defect-Free FLCD's with High Optical Quality Based Upon New FLC's

We have designed new FLC compounds and new FLC materials based upon them, and we have found general criteria of the preparation of FLCD’s with uniform and stable orientation of FLC materials [1]. The influence of the molecular structure on the quality of orientation, on thermal and mechanical stability and on the contrast ratio was investigated by using 4 types of aligning materials in the thin and thick testing cells. The correlation between the number, type and amount of achiral and 3-, 4-ring chiral compounds in the mixture and contrast ratio of our FLCD’s was found. Finally we optimized the FLC-mixtures, alignment conditions and we prepared the defect-free samples with optical contrast about 700:1

XRD Study of New FLC's: Correlation Between the Chemical Structure of Molecules, the Sign of the Optical Rotation and the Tilt Angle

New 4-ring FLC’s with different positions of lateral substituents and bridge fragments in the central core were synthesized. These compounds have a wide temperature range of the smectic C* phase and similar length of the molecules. Different ways of the preparation of the FLC mixtures with a high tilt angle and the results of electrooptical and XRD measurements of the FLC mixtures based upon the chiral compounds are presented

Simulation of coolant mixing in the vortex device

Настоящая работа посвящена исследованию процесса взаимодействия потоков теплоносителей при смешении в циклонно-вихревых агрегатах, в частности в вихревом смесителе, с целью применения результатов моделирования для проектирования вихревых конденсаторов.The present work is devoted to research of process of interaction of streams of coolant when mixed in a cyclone-vortex assemblies, in particular in a vortex mixer, with the aim of applying the results of simulation for the design of vortex capacitors

Tricolor Technique for Visualization of Spatial Variations of Polydisperse Dust in Gas-Dust Flows

The aim of this work is to construct an algorithm for visualizing a polydisperse phase of solid particles (dust) in an inhomogeneous flow of a two-phase gas-dust mixture that would allow us to see, within one plot, the degree of polydispersity of the dust phase and the difference in the spatial distributions of individual fractions of dust particles in the computational domain. The developed technique allows us to reproduce concentrations from one to three fractions of dust particles in each cell in the computational domain. Each of the three fractions of dust particles is mapped to one of the main channels of the RGB palette. The intensity of the color shade is set to be proportional to the relative concentration of dust particles in this fraction. The final image for a polydisperse mixture is obtained by adding images in each of the three color channels. To visualize the degree of polydispersity, I propose depicting the spatial distribution of the entropy of the dust mixture. The definition of the entropy of a mixture is generalized to take into account the states of a mixture with zero number of particles in the mixture. They correspond to dust-free sections of the computational domain (voids). The proposed method for visualizing the polydispersity of a mixture of particles is demonstrated using the example of dynamic numerical modeling of the spatial features of dust structures formed in turbulent gas-dust flows and in flows with shock waves

Shock-Free Ferroelectric Liquid Crystal Compositions: Optimized Chiral Compounds and Their Mixing Ratio with Non-Chiral Components

The best chiral compounds for the design of shock-free ferroelectric liquid crystal compositions with a wide temperature range of the chiral smectic C phase have been developed. For these experiments about 70 different 4-ring chiral compounds were synthesized and investigated. The influence of the chiral fragment, the mixing ratio between chiral and non-chiral molecules, and the pretilt angle of the alignment materials on the quality and on the mechanical stability of the orientation were investigated. New optimized ferroelectric liquid crystal compositions for the fabrication of shock-free ferroelectric liquid crystal displays with high contrast ratio are presented

ПРОЯВЛЕНИЕ ЗАКОНА ВИБРОПОЛЗУЧЕСТИ В НАКОПЛЕНИИ ОСТАТОЧНЫХ ДЕФОРМАЦИЙ ИЗГИБА СТЕРЖНЕЙ ШАТУНОВ ДВС

The provision about the deformation of the bend in connecting rod bars caused by the effect of ICE amplitude-frequent working load emerged in the plane perpendicular to the plane of the swinging connecting rod served as a working hypothesis of research data. Herewith, the direction of the bending moment depends upon the presence and direction of working surfaces angle deviation (WSAD) in the connecting rod bearing. According to the data of different authors, the numerical values in the parameters of angle deviations of assembly surfaces in ICE basic parts after the first operation cycle are many folds higher than maximal permissible values. Assembly surfaces angle deviations (ASAD) in ICE basic parts are characterized by the following parameters: 1) deviation from the axis perpendicularity of cylinders and pockets of crankshaft main bearings( γ 1 ); 2) deviation from axis parallelism of the crankpins and crankshaft main journals (  γ 2 ); 3) conic crankpins (  γ 3 ); 4) axis deviation of connecting rod ends from their being in the same plane (axes misalignment) when a connecting rod bar twisted ( γ 4 ); 5) deviation from axis perpendicularity of bosses and piston openings (  γ 5 ); 6) deviation from axes parallelism in upper and bottom connecting rod ends ( γ 6 ). Analysis of the patterns on the effects of the ASAD parameters mentioned showed that when deviated from the axis perpendicularity of cylinder and bores for the crankshaft main bearings ( δ∆ = γ1 > 0)and the algebraic sum of the rest of the (  γ2+ γ3+ γ4+ γ5+ γ6 = 0,0 ) equaling 0, the connecting rod bar bend direction does not change its direction when the piston moves from the upper dead point (UDP) to the bottom dead point (BDP) and from (BDP) to (UDP).With the error status of the kind in assembly surfaces, the lengthway contact of working surfaces.Рабочей гипотезой данных исследований служило положение о том, что деформация изгиба стержней шатунов происходит под действием амплитудно-частотной рабочей нагрузки двигателей внутреннего сгорания (ДВС), возникающей в плоскости, перпендикулярной к плоскости качания шатуна. При этом направление изгибающего момента зависит от наличия и  направления углового отклонения рабочих поверхностей (УОРП) шатунного подшипника. Уровень численных значений параметров угловых отклонений сборочных поверхностей базовых деталей ДВС после первого цикла эксплуатации, по данным разных авторов, в разы выше предельно допустимых значений. Угловые отклонения сборочных поверхностей (УОСП) базовых деталей ДВС характеризуются следующими параметрами: 1) отклонение от перпендикулярности осей цилиндров и гнёзд коренных подшипников коленчатого вала ( ) γ 1 ; 2) отклонение от параллельности осей шатунных и коренных шеек коленчатого вала(  γ 2 ); 3) конусность шатунных шеек(  γ 3 ); 4) отклонение осей головок шатуна от положения в  одной плоскости (перекос осей) при скручивании стержня шатуна (  γ 4 ) ; 5) отклонение от перпендикулярности осей отверстий бобышек и поршня(  γ 5 ); 6) отклонение от параллельности осей верхних и  нижних головок шатуна(  γ 6 ) . Анализ схем влияния упомянутых параметров УОСП показал, что при отклонениях от перпендикулярности осей цилиндров и расточек под коренные подшипники коленчатого вала ( δ∆ = γ1 > 0) и алгебраической суммы остальных параметров (  γ2+ γ3+ γ4+ γ5+ γ6 = 0,0 ) равной нулю, направление изгиба стержня шатуна не меняет своего направления при движении поршня от верхней мёртвой точки (ВМТ) к нижней мёртвой точке (НМТ) и от НМТ к ВМТ. При таком состоянии погрешностей сборочных поверхностей продольный контакт рабочих поверхностей меняет своё положение, но направление изгибающего момента является постоянным. Следовательно, действие изгибающего момента в одном направлении от амплитудно-частотной рабочей нагрузки ведёт к накоплению остаточных деформаций изгиба стержней шатунов. Результаты экспериментальных исследований на обкаточном стенде ДВС подтвердили выдвинутую гипотезу о проявлении закона виброползучести в накоплении деформаций изгиба стержней шатунов при рабочих температурах. Результаты исследования причин изгиба стержней шатунов являются основой технологической стратегии обеспечения точности сборки ДВС методом неполной взаимозаменяемости на станции технического обслуживания (СТО) автотракторной техники

Эффективный метод синтеза замещенных 2-метилбензофуранов

The efficient method for synthesis of substituted 2-methylbenzofurans based on aromatization of 3-substituted-6-allylcyclohex-2-еnones in the presence of iodine with subsequent potassium hydroxide treatment of 2-iodomethyl-2,3-dihydro-benzofuran intermediates, has been described.Предложен эффективный метод синтеза замещенных 2-метилбензофуранов, основанный на ароматиза-ции 3-замещенных-6-аллилциклогекс-2-енонов в присутствии иода, последующей обработке промежуточных 2-иодметил-2,3-дигидробензофуранов гидроокисью калия

Liquid crystal displays and anisotropic materials development in Belarus: present and future

Research, development and production of liquid crystal displays and materials in Belarus are presented. The original methodology of the creation of advanced devices and anisotropic materials is considered. The proposed approach of design of new devices, anisotropic materials and ordered nanostructured surfaces and layers is based on numerous data obtained in the last decades in the study of liquid crystals and ordered fluids; on the regularities of the evolutionary development of natural organic compounds; on the use of the anisotropy of the molecules of polyfunctional compounds for the design of new molecular structures (molecular engineering), films, liquid crystals, micelles, membranes, etc. and for the creation of anisotropic ensembles of molecules and biological systems