Table of Contents

  • AIR COOLING INFLUENCE ON THE PERFORMANCE AND CHARACTERISTICS OF TURBOCHARGED DIRECT INJECTION GASOLINE ENGINE

    pg(s) 104-107

    The paper presents numerical analysis of air after turbocharger cooling process and its influences on the gasoline engine operating parameters. Analysis was performed with numerical 0D (zero-dimensional) simulation model by using two sets of simulations – for gasoline turbocharged engine without air cooler and for the same engine with air cooler included. Between engine rotational speeds of 1000 rpm and 5000 rpm, air cooling process increases analyzed engine developed power and engine torque up to 20.67%, increases cylinder maximum pressure up to 17.03%, increases engine volumetric efficiency up to 23.65% and reduces brake specific fuel consumption up to 1.32% when compared with the same engine without air cooler. At the highest engine rotational speeds (between 5000 rpm and 6000 rpm) it was observed that selected air cooler does not offer the required and expected performance, so air cooling process in this engine operating area can and should be improved.

  • INDUSTRY 4.0 AND SUPPLY CHAIN INTERACTION ANALYSIS WITH FUZZY ANALYTICAL HIERARCHY PROCESS

    pg(s) 108-113

    Industry revolution is not a new thing for the world and it has been coming up till the machines were invented. And now, Production authorities have discussed the Industry 4.0 which is combinations of the existing manufacturing and large technological innovations and also, Supply Chain perspective is changing that product flows will become regional. This research paper will firstly aim to clearly understand the Industry 4.0 and what kind of changes occurs into the Supply Chain Environment. The Second part of the Research will focus on the Performance Measurement and Decision Making Analyzing which comparison between before Industry 4.0 and after applications of Industry 4.0. Fuzzy Analytical Hierarchy Process Method is used for determination of comparison.

  • CHELATING EXTRACTION TECHNOLOGY IN REMOVING AND RECOVERING HEAVY METALS FROM MUNICIPAL SLUDGE

    pg(s) 114-117

    Comparable heavy metal extraction efficiency using different chelating aminopolycarboxylic acids was studied with sewage sludge as well as sludge-soil mixtures. EDDS and MGDA showed only slightly lower extraction efficiency in comparison with EDTA, at solution pH 6 and 25°C. Chemical fractions of HM in the sludge were determined using sequential extraction. According to their stability in the environment (in sulphide and residual fractions) the investigated heavy metals can be ranked as follows: Cr> Pb> Ni> Cd> Zn ≈ Cu. It was found out that methylglycinediacetic and S,S’-ethylenediaminedisuccinic acids had much better biological degradation properties than widely for metal complexation used ethylenediaminetetraacetic acid – EDTA. Possibility to utilize metal-contaminated extraction solution by chelant recovery with calcium hydrosilicate was also investigated.

  • SOME OF THE INOVATIONS APPROCHES IN PLASTIC INJECTION MOULDING TECHNOLOGY

    pg(s) 118-120

    In today’s fast changing world it is crucial for businesses to stay in touch with the latest developments in the processing technologies in order to remain competitive on the market. The paper reviews the most recent innovations in plastic injection molding technologies. Their pros and cons and their possible impact on manufactured materials. And how these processes improve the design, function of products, automatically, and cost effectively.Furthermore, the paper researches the application of the injection-moulded products in our everyday lives.

  • GEOMETRIC METHOD FOR DETERMINIG RADIANT HEAT EXCHANGE IN VACUUME FURNACE

    pg(s) 121-123

    Heating chamber in vacuum furnace is closed thermal system where heat exchange is predominantly radiant. Conductive heat exchange is defined by well-known formulas. In order to determine the temperature condition of the object during heating (cooling), it is necessary to determine the angular coefficient of radiant exchange on every other objects. The known in the literature methods, including the geometrical once, have a solution for heat exchange only between two objects. The applications for real heat systems is partial and limited. It is presented a geometric model for calculation the angular coefficients of radiant interchange for closed thermal system. Heat exchange is taking place between an unlimited number of objects and a free-standing arrangement between them. The model allows solutions for objects of different geometric form in the presence of intermediate objects, as well as barriers for heat radiant from their own surfaces. The paper has been verified by a solution of thermal problems for vacuum furnaces.

  • WORLD URANIUM MINING PRODUCTION

    pg(s) 127-130

    Uranium mines operate in some 20 countries, though in 2017 some 53% of world production came from just ten mines in four countries, with these four countries providing 77% of the world’s mined uranium. Countries have different degrees of sovereign risk affecting their attractiveness for mining investment, different royalty and tax regimes, and different availability of skilled workers. These factors will have already influenced the mineral exploration which has led to the identification of an orebody before any mining issue has arisen.

  • CHARACTERISTICS OF INVESTMENT PROCESS AND ATTRACTIVENESS OF INDUSTRY AND ENTERPRISE

    pg(s) 131-132

    Theoretical approaches to the investment process` nature definition and the order of investment process` stages have been analyzed. The main trends of enterprises` investment process` introduction have been specified. Dynamics of enterprises` investment process` have been identified. The main features of investment cycle and its liaison with scientific and technical progress have been marked. It has been suggested to study industries` investment attractiveness as integral characteristic of separate economic fields regarding development perspectives, investment yield, and level of investment risks. It has been found out that certain industries` investment attractiveness is evaluated amid enterprise`s investment strategy`s development and field diversification of the investment portfolio.

  • EXTENSION OF THE STAGES OF INVESTMENT PROJECTS` EFFECTIVE MANAGEMENT ON THE BASIS OF OPERATIONAL ACTIVITY`S RATIONAL ORGANIZATION

    pg(s) 133-136

    Problem issues of enterprises` investment projects introduction have been studied. Structure of every enterprises` investment projects management stage and their characteristics have been defined. Goal of every investment project`s introduction stage taking into account investment resources need and information processing as for the applied investment projects have been marked. Stages of business investment projects `efficient management regarding development of efficient system of decision making control of managerial system have been suggested. System of investment projects` management not identical to existing ones has been submitted. It has been implied to study it as set of elements, which determine planning process, analysis, organization, introduction and monitoring of an investment project, planned budget, project timing, considering environmental threats and risks to take meaningful decisions, avoiding mistakes and improving organizational structure of an investment project.

  • INDUSTRIAL ENTERPRISES` INVESTMENT PLANNING FOR SUSTAINING THEIR ACTIVITIES

    pg(s) 137-139

    The reasons of unsuccessful capital investments, which provide activity of industrial enterprises have been studied. It has been found out that to ensure industrial enterprises` sustainability, it is important to have the reserve of effective investments ideas . It has been determined that when planning industrial enterprises` activities it is important to take into account the probability of investment forecasts. The principal algorithms for actions in the process of planning to eliminate various types of deviations of actual results of investment activity from predicted ones have been proposed.

  • FORMATION OF AN ENTERPRISE`S SYSTEM OF INVESTMENT ACTIVITY MONITORING

    pg(s) 140-143

    It has been proposed to the main stages of controlling based on its business investment principles. The main features of certain types of business investment controlling have been given. An example of a priorities system of an enterprise net investment returns` controlled indicator has been formed. It has been proposed the key stages of the monitoring system` building regarding investment activity controlled indices`. Business investment activity monitoring system has been worked out.

  • INVESTIGATION THE CONDITIONS FOR OBTAINING BULGARIAN YELLOWCOLORED PAVINGS, EQUIVALENT IN COLOR TO THE IMPORTED PRODUCED ON BASE OF SEDIMENTARY ROCK

    pg(s) 144-146

    The development deals with the study of the conditions for appearance of yellow color in ceramic products, obtained from local sedimentary marl rocks from the region of Popovo town, field of Targovishte. Reproduction of the conditions of high temperature liquid-phase synthesis of products such as pavings, tiles, etc., by modifying the composition of the marls. Expanding the sintering interval of rectifying the alkaline-earth oxide content and increasing the phase formation time. The researches are part of the creation and implementation of a technology for production of pavings with equivalent yellow color of the imported standards but with higher tribological and physic-mechanical indicators.

  • GRADIENT STRUCTURE AND METHODS FOR THEIR PREPARATION

    pg(s) 147-148

    The development of new technological methods of SPD for the production of mass production with improved properties due to the deep grinding of the original structure is an important task. The purpose of this work was to study the active bending to grind the structure and create promising, for operational use, gradient structural states in long rods of copper grade M1. Active bending was performed using an extruder according to the “Conform” scheme. The results of the analysis stress-strain state is using computer simulation and structures using optical microscopy. It is established that the active bending method provides over four processing cycles high strain accumulation (e = 3-4) and formation subgrained- structure UFG type.