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  • Author: Pavol Bozek x
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Abstract

The article evaluates the failure rate of devices in the Mechanical Processing Plant using a traditional quality tool, the Pareto-Lorenzo diagram. A comparative analysis of failure rates was performed, recorded in repair, inspection and maintenance card. Then, changes were proposed in order to reduce failure rates and earlier detection of equipment malfunctions. In order to analyze the failure rate of grain washer equipment during thick coal preparation process, one quality management tools was used - the Pareto-Lorenzo diagram. In this case, it is important to assess the mechanical failure of devices, and demonstrating which devices generate most repairs. Based on materials made available by the mine, such as: Repair, inspection and maintenance cards, Device cards, DTR documentation. Quantitative and qualitative assessment the most frequently occurring mechanical failures during operation of devices in process enrichment of coarse sizes was carried out. An attempt was made to assess failure rate of devices on a grain washer. A comparative analysis of failure rates in 2015-2017 recorded in the repair, inspection and maintenance card was carried out. Then, changes were proposed to stand, in order reduce failure rates, and earlier detection equipment malfunctions.

Abstract

Drilling with a rotary steerable system, the mechanical drilling speed increases by two times compared to drilling with a screw bottom-hole motor, which provides significant savings drilling-time. The effective length of the horizontal elbow increases, which enables to increase the production rate more than twice. It is found that in comparison with the bottom hole motor, rotary steerable system provides drilling smoother barrel, which reduces the risk of accidents to come out. The dependence between the type of the bent housing and the most rational fields of its application is revealed, recommendations on the choice of the rotary steerable system for various issues of directional drilling are developed.

Abstract

This paper presents the technology of production of synthetic fibrous materials from PET-row by vertical blowing method. The formation of fibers from the melt of thermoplastics by vertical blowing method is accompanied by complex and specific phenomena, so creation of new progressive technologies, high-performance machines and units for producing such materials is impossible without process modeling, which can significantly reduce the number of natural tests, cost and development time and choose optimal operating modes. The motion of the molten material in the melting unit of the hydrostatic type is determined from the Poiseuille formula. Also in the article proved that the greatest impact on process productivity is made by the melting unit, exactly by outlet radius and the pressure change of compressed air, acting on the molten material surface. The increase in the height of the molten material column in the main cylindrical chamber of melting unit also leads to increase of process productivity.

Abstract

Submission is focused on completing the information system about quality, operation, automatic testing and new evaluating method of vehicle subsystem. Numeric analysis is carried out on the base of automatic collection and systematic recording of commercial car operation. Proposed new information system about operation and trial process allows verification according to the proposed method. Critical components verified in laboratory conditions are detected by numeric analysis of reliability. Quality level increasing not only for final product, but also related automatic test laboratory for cars is the result of respecting these principles.

Abstract

The main purpose of processing of tough-to-machine materials is improving of cutting process of steels with different physicochemical properties and alloying by means of various chemical elements in combination with heat treatment. Producing of high quality surface layers depends on properties of material used to make details, that is why reasons of tough machining were identified: influence of chemical composition and resulting structure. The studies of grinding of tough-to-machine materials were undertaken by means of grinding wheels made from synthetic diamonds as they are most resistant and highly-productive. Based on the studies recommendations for using of characteristics of grinding wheels and tough-to machine steel grades are given.

Research on heat processes during grinding allows us to determine patterns showing how cutting speed, detail motion speed, area and action period of contact influence temperature and speed of heat processes in surface layers as well as depth of heating. These patterns also give the chance to show interrelation between temperature and rate of heating and cooling. This gives an opportunity to predict state of structure of surface layer of details made of tough-to-machine steels under different machining conditions reasonably.

Abstract

This paper presents the technology of production of synthetic fibrous materials from PET-raw by vertical blowing method. Fibre production by vertical blowing method is accompanied by complex and specific phenomena; therefore, development of new progressive technologies, high-performance machines and units for producing such materials is impossible without process modelling, which can significantly reduce the number of natural tests, cost and designing time and select optimal operating modes. Molten material motion in the melting unit of the hydrostatic type is determined by means of Poiseuille formula. Furthermore, the paper has proven that the melting unit has the greatest impact on process productivity by means of outlet radius and the pressure change of compressed air acting on the molten material surface. Increase in the height of the molten material column in the main cylindrical chamber of melting unit also leads to an increase in process productivity.

Abstract

The contribution deals with the comparison of possibilities of utilizing two experimental methods: digital and classical holographic interferometry for the visualization of beam motion. The girders are used in civil and mechanical engineering and considering the technical point of view it is necessary to learn to what extent the beam is deformed at the load and how much it can withstand.

Abstract

The paper deals with ionization impact on efficient cleaning of air in a measuring chamber which has been cleaned and closed against any outer impacts (e.g. impurities, dust from another room, human odours). Smoking has an impact on the number of positive and negative ions including the concentration of particulate matter PM10. We investigated the ion concentration according to the presence of cigarette smoke in the room and according to the change of lit cigarette distance from the supply of ionized air. Due to the experiment there was simulated smoking at the relative air humidity φ = 37 % and φ = 39 % and temperature of 20 °C in the room. Increased PM10 concentrations were caused only by cigarette smoke pollution or more precisely by artificially created higher humidity in the measuring room excluding ambient environment impacts. The aim of the experiments was to prove influence of ionization on the elimination of cigarette smoke. The measurements showed that the highest efficiency of PM10 particulate removal was achieved when the distance of smoking cigarettes from ionization source was 3 m and the air humidity was 39 %. The consequent increase of the distance of smoking cigarettes from the ionization source significantly decreased the efficiency of particle removal. The difference between ionized and natural air is minimal at the bigger distance.

Abstract

The geometric model accuracy is crucial for product design. More complex surfaces are represented by the approximation methods. On the contrary, the approximation methods reduce the design quality. A new alternative calculation method is proposed. The new method can calculate both conical sections and more complex curves. The researcher is able to get an analytical solution and not a sequence of points with the destruction of the object semantics. The new method is based on permutation and other symmetries and should have an origin in the internal properties of the space. The classical method consists of finding transformation parameters for symmetrical conic profiles, however a new procedure for parameters of linear transformations determination was acquired by another method. The main steps of the new method are theoretically presented in the paper. Since a double result is obtained in most stages, the new calculation method is easy to verify. Geometric modeling in the AutoCAD environment is shown briefly. The new calculation method can be used for most complex curves and linear transformations. Theoretical and practical researches are required additionally.

Abstract

A simulation model of brushless DC motor (BLDC) control and diagnostics is considered. The model has been developed using a freeware complex “Modeling in technical devices”. Faults and diagnostic parameters of BLDC are analyzed. A logicallinguistic diagnostic model of BLDC has been developed on basis of fuzzy logic. The calculated rules determine dependence of technical condition on diagnostic parameters, their trends and utilized lifetime of BLDC. Experimental results of BLDC technical condition diagnostics are discussed. It is shown that in the course of BLDC degradation the motor condition change depends on diagnostic parameter values