Science of materials and mechanical Engineering

Experimental and Theoretical Analysis of Flow Structure in the Vortex Chamber with End Jet Control

In order to find low-powered control system of working flows in vortex chambers (VC) of energetic and technological equipment the compound structure of shear current in one of the most powerful vortex formation (“central quasi-solid vortex” — CQSV) inside of VC dead-end zone was investigated under condition of closed coaxial end jet control actions. The principle of mutual receptivity of vortex structures on macrolevel was taken as a basis upon study of geometric and operating characteristics of these actions.

Effect of Microwave Sintering Temperature on Structure and Mechanical Properties of Hydroxyapatite Ceramics

The aim of the paper was to investigate features of microwave sintering of biogenic hydroxyapatite obtained for filling of various bone defects in medicine. The samples were prepared at high-temperature muffle furnace (1,5 kW, 2,45 GHz) at 800, 900, 1000 and 1100 С. It was established that increasing of microwave sintering temperature did not lead to a rapid increasing of grain size and agglomerate formation. The prepared materials have homogeneous fine-grained structure with average grain size 0,42–0,56 мm and average pore size is equal to 0,5 мm.

Wall Boundary Layer’s Viscosity Definition in the Forming Equipment Channels for Polymers Processing

The research objective is definition of the processed polymeric material melt properties in a wall boundary layer of working equipment channels. Setting the slip coefficient, that provides a linear relation between the viscosity in the boundary layer and the slip coefficient which often don't correspond to reality is a standard procedure in one of the most common polymer melts flow numerical simulation software package Ansys Fluent.

Application of Impulsive Electromagnetic Affects for Crystallization Process of Joints for Spot Welding

Results of external influenced impulsive electromagnetic affect research to crystallization joint process with construct and stainless steel, and dissimilar material joints for spot welding are researched. Changes in different weld spot structures are shown. The samples obtained using design mode of spot welding with the impulsive electromagnetic affects, were compared and an increasing in the dispersity structure by twice times was indentified, but the dendrite width was decreased. Impulsive electromagnetic affect influence on weld line length is studied.

Construction Improvement of Scintiscanner for Laser Therapeutic Settings

Создана оптимальная конструкция сканера лазерного луча и методика определения его параметров и условий облучения. В них могут быть заинтересованы районные, сельские клиники и больницы, фельдшерско-акушерские пункты, где проблематично применение и обслуживание сложных по конструкции и с процессорным управлением устройств. Взамен них разработаны простые и оригинальные конструкции сканеров лазерного луча с обеспечением постоянного уровня плотности энергии в зоне облучения, предназначенные для потребностей медицинских заведений с небольшими доходами.

Phase Composition, Microstructure and Mechanical Properties of AlCrCoCuFeNiх High-Entropy Alloys System

In this study, the AlCrCoCuFeNiх (where х = 0; 0,5; 1; 2 and 3) high-entropy alloys were prepared by vacuum arc melting and their phase composition, microstructures and mechanical properties were investigated. According to X-Ray analysis data, phase composition of alloys depending on Ni content. It was found that the structure transformed from mixture B2+FCC solid solutions into FCC solid solution with the increase of Ni content. Quantity of BCC phase solid solution is decreased with increasing Ni content, and, respectively, the quantity of FCC phase solid solution increases.

Model of Bof Lapping with Setted Temperature and Carbon Content

In order to increase the accuracy of process control refinement converter smelting, a series of mathematical models of controlling were developed. Melting model was created to calculate the charge (“static control”), control fuse in the process of purging (“dynamic management”) and finishing melting after the measurement of carbon content and temperature of the bath without interrupting the purge and calculation of reductants. The influence of control actions on the process of finishing converter smelting was studied.

Calculation of Probability of Implementation of Requirements to Diameter of Pores in the Weld-Fabricated Guy-Sutures

Mathematical dependence accounting changeability in formation of pores at welding and allows expecting probability of implementation of requirements to the diameter of pores from the experimentally found descriptions of the statistical distributing of amount and diameter of pores on the single area of the weld-fabricated guy-sutures is in-process shown out. For the development of mathematical dependence the static laws of distributing of Veybull and Puasson and rule of probabilities increasing were used. Adequacy of the theoretical dependence was tested by calculation of boundary conditions.

Surfaces’ Roughness of Composite Sliding Bearings of Printing Machines at Fine Cubanite Grinding

The research results of sliding bearings’ roughness formation and which were manufactured from new composite materials on the base of stamp steels wastes for high-speed printing machines friction units were presented in the article. It was shown that high quality parameters of working surfaces, for example, roughness and other quality parameters are formed as a result of interaction between parameters of cutting by cubonit tools such as granulosity and properties of abrasive tools for the fine grinding technology.

Flows Features in the Internal Channels of Involute External Gear Pumps

Results of investigations of external gear pump with involute tooth profile which goal was to obtain the flow patterns in the suction and discharge chambers, and in meshing region and examining the effect on them of operating parameters of the pump were presented. Flow patterns were obtained by visualisation of fluid flow with a high-speed video recording of working process of the pump with a lid made of a transparent material. As result of video analysis appearance of cavities in the fluid closed in trapped volume was found.