Journal "Research Bulletin of National Technical University of Ukraine "Kyiv Polytechnic Institute" (Naukovi visti) publishes original research results and practical developments from areas of technical, physical, mathematical, chemical and biological sciences.

Influence of Bast Fibers Treatment Stages on Microcrystalline Cellulose Indices

The process of obtaining microcrystalline cellulose from non-wood plant bast fibers (flax, hemp, kenaf) with using preliminary acid hydrolysis, alkaline sulfite -alcohol method delignification and oxidation-organosolvent processing was investigated. It is established that the conduct preliminary acid hydrolysis in the first step of obtaining microcrystalline cellulose can significantly reduce the mineral content (at 62–75 %), partly yield of pulp (at 9–12 %) and residual lignin content (at 20–30 %) compared of feedstock.

Silicon Photomultipliers as Alternative System of Photomultipliers of Neutral Particle Detector in Electron-Proton Accelerators

Measurement of events that produce particles, in particular photons, is a powerful tool for the study of subatomic constituents of the universe. The purpose of this research is to consider placement in the detector, study properties and implementation of updated ZEUS detector photomultipliers for possible use in future electron-proton accelerators. The most important part of the detector ZEUS, especially when measuring neutral particles such as photons, is calorimeter ZEUS, based on the phenomena of photon emission from the excited electron, which is returned to a lower energy level.

Techonlogy of Ultrasonic Control of the Well-Bonded Pipe Coupling Space Filling

The method of well-bonded pipe coupling space filling control by means of ultrasonic NDT methods has been proposed. Use of ultrasonic NDT method for coupling space filling with self-hardening substance (both compound and molten metal coupling space filling) has been analyzed. Taking into consideration the high temperature of the repair structure during repair works performance when using a molten metal, which is determined by high temperature, the application of piezo-electric transducers is ineffective.

Method for Assessing Modulation Transfer Function of Trifocal Intraocular Lens

The article investigates the quality of images formed by multifocal optical elements. The method for calculating of multifocal diffractive lens modulation transfer function (MTF) at presence of background is proposed. The method is based on a geometric calculation of the intensity of background images and the diffraction efficiency of the main image in each focal plane is considerated. The article has studied the contrast of main images formed by trifocal intraocular lens (IOL).

Efficiency of the Functional Distribution of Solid Fuel in Layered System Consisting of Ore-Flux-Fuel Compositions

In this article processes of pelletizing and sintering iron ore pellets with different distribution of solid fuel in multilayer system were experimentally investigated. The influence of the functional distribution of solid fuels on the compressive strength and the degree of metallization fired pellets was studied. Compressive strength of burnt pellets with basicity of 1.4, which contain increased amounts of particulate fuel in range of 1,6–2,35 kN/pellet and not characterized by high indices, although GOST has indices on level 0,2–0,95 kN /pellet.

Monitoring of Welding Processes with Application of Artificial Neural Networks

The paper presents a summary of methods of monitoring systems’ development for the processes involving heating of filler material and/ or base metal by the electric current and with periodical shortages of the welding circuit. The processes investigated were MAG welding, underwater flux-cored welding and flash-butt welding. Details of experiments, primary data processing procedures based on statistical analysis methods are described, the aim of primary processing being obtaining of informative parameters of the welding processes.

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.