Rational exploitation of super hard grinding wheels with metal bond requires estimation of constituent costs of grinding process and dressing of grinding wheels. In the article the method of electrochemical dressing of super hard grinding wheels and economical analysis of electrochemical dressing of these kind of grinding wheels consisted in assessment of selected costs of this process has been presented. Also analysis of costs of the grinding process has been depicted. Obtained relationships allowed us to estimate contribution of respective component of costs of grinding process using super hard grinding wheels and are basis for their optimization.
Machines. Technologies. Materials.
Vol. 10 (2016), Issue 4
Table of Contents
The aim of the paper is to establish the kinetic parameters of the thermal degradation of the organic mass of primary coal tar (PKC) in the presence of pseudo-homogeneous iron catalysts (PGZHK).
COMPARATIVE ANALYSIS OF MODELS DSAT-16 AND MOTP_VTU TO CALCULATE THE PROPERTIES OF THE LAYER IN THE WELDING AREApg(s) 10-13
The paper presents the characteristics of a modern software system for modeling and optimization of technological processes MOTP_VTU. It outlines the possibilities also to use the system at the design stage. A comparative analysis is performed of three characteristics to apply the new software system MOTP_VTU related to a similar existing one – DSAT-16. via similar systems it is possible to expand the basis of constructions and of functional materials in low technological level during exploration of the set of properties of these materials. This process of realization of scientific and technical ideas is a process to search via multi criteria support of decision making between the project task and the actual possibility, determined by the chemical composition and the processing-mode parameters.
The paper presents the results of the synthesis of the xerogel of vanadium in the interaction of vanadium pentoxide and ammonium. It is shown that as a source of vanadium pentoxide can be used successfully vanadium carbonaceous – siliceous shales. Using obtained vanadate ammonium in receiving technology of vanadium xerogel is more cost effective process than the use for this purpose the chemical reagent. Integrated use of this unique raw material is a critical component of modern waste-free and environmentally friendly technologies to highlight not only the connection of valuable components, but also the raw material for the production of vanadium xerogels.
Synthesized by sol-gel method based on vanadium oxide xerogels with partially ordered highly layered structures already are widely used in various fields of science and technology due to their unique properties. Scope xerogels vanadium: production photocatalysts, composites, membranes and ion exchange materials.
The subject of research in this paper is a conveyor drive unit from a conveyor coal transport system that is used by SM "Brod – Gneotino" to SM "Suvodol" (Power plant REK Bitola-Macedonia) because of its existing signs of increased vibrations. Vibration measurements of the drive transporter T5 was obtained to determine the vibration state of the drive unit. Each driveline (electric motor – hydro clutch – gear reducer) has ten measuring points – probes to monitor temperature and ten measuring points – probes for monitoring the vibration of the electric motor bearings and bearings of the gear reducer.
Through proper FFT analysis of the vibration signal that has been obtained by the probes we will determine further conclusions and recommendations regarding the state of the elements of the system and their dynamic stability.
THE SOLUTION OF THE PROBLEM OF ONE-PARAMETER PERTURBATION OF THE VISCOUS INCOMPRESSIBLE LIQUID MOTION THROUGH STRAIGHT ROUND PIPEpg(s) 20-22
In this paper the analytical solution of the differential equation, describing viscous incompressible liquid motion through straight round pipe, with one perturbation parameter is given. The perturbation is introduced into the equation through the disturbed viscosity, depending on the temperature. The solution of the corresponding differential equation is sought in the form of a series in the small parameter. Thus the flow reaction to the internal disturbance is studied. The solution, presented in this article, gives an opportunity to further studying the temperature impact on a viscous weakly compressible liquid motion through a pipe. This research may be of interest to the problems of hydrocarbons control flow through main pipelines.
In this paper elastic deflections of press frame when symmetric load is applied have been investigated and press stiffness calculated. The commercial FEM package ABAQUS was used to estimate elastic stress and elastic deformation of press frame in case of 6.3 MN hydraulic press. For validation of FE results both axial and radial displacements of the press frame were measured by means of universal displacement transducers. Obtained results are compared and discussed.
Our paper’s aim is to emphasis the useful combination between a functional decomposition approach met in literature as FAST Functional Analysis and System Technique – a technique used to decompose logically on levels of abstractisation and ideally solution independent product’s (system) functions and consistent with this decomposition to realize a Failure Modes and Effects Analysis analyze. In this way, for each function inventoried and organized on each detail level there will be associated their specific failure modes. This approach is applied next to a mandrel.
THERMOCHEMICAL CALCULATIONS AND EXPERIMENTAL INVESTIGATIONS ON Mo-Ni-B ALLOY SYSTEM PRODUCED BY COMBUSTION SYNTHESISpg(s) 31-32
In this study, Mo-Ni-B alloy system which can be a new hard alloy alternative to tungsten base cemented carbides, was investigated by means of thermochemical calculations and experimental trials. Thermochemical calculations were carried out to estimate the adiabatic temperatures and possible product compositions in the alloys by using FactSage 7.0 thermochemical software. The combustion synthesis process was performed under normal gravity and air in Cu copper crucibles by using metal oxides (MoO3 and NiO), boron oxide (B2O3) as a boron source and aluminum (Al) as a metallic reductant. Alumina, (Al2O3) as a functional additive (diluent), were also added in order to reduce the adiabatic temperature of the reaction. Since the attained reaction temperatures for this system during the exothermic SHS process is so high (above 2000 °C), the reaction is self-sustaining and the melt consists of insoluble mixture of metallic compound and oxide phase which can be segregated under normal gravity force.
This study investigated surface hardness, roughness, and abrasion resistance of hot press molded wood plastic composite (WPCs) panels coated two types paints, water- or solvent-based paints. The WPC panels are produced from different amounts of pine wood flour (30 to 60 wt%), virgin polypropylene (37 to 67 wt%) and 3 wt% maleic anhydride polypropylene (MAPP). The surface abrasion resistance and hardness of the WPC panels painted with water or solvent based paints increased up to 50 wt% wood flour content, but further increment in the wood flour content decreased the abrasion resistance and hardness. The surface roughness of the painted WPCs increased with increasing wood flour content. The WPCs painted with solvent-based paints showed better surface quality as compared to the WPCs painted with water- based paints.
in this study, the hard facing with Fe-Cr-C base welded wire and Fe-Cr-Nb-C cored welding wire by using submerged-arc welding method in single-pass, two-pass and three pass over the pieces of carbon steel (St37 )was done. Cored welding wire Fe-Cr-Nb-C by an approximate ratio of 5.41 Cr to C ratio, was containing 5.6 to 7% of the niobium element. scanning electron microscopy, optical microscopy, X-ray diffraction and point analysis, indicates the presence of carbides (Fe, Cr)7C3 and Nb2C in hardened samples with Fe-Cr-Nb-C welding wire. The results showed that with increasing number of hardened passes, the percentage of carbon, chromium and niobium concentrations increased and as a result the dilution percent was decreased that cause to increasing hardness and better performance. test results indicate higher hardness of hardened samples with Fe-Cr-Nb-C welding wire compared to samples hardened with Fe-Cr-C welded base wire. With increasing number of of hard passes, hardness was increased, so that the highest and lowest hardness is related to three pass samples that was hardened with metal cored wire Fe-Cr-Nb-C.The reason of increased hardness in three-pass samples hardened with Fe-Cr-Nb-C metal cored wire was to with increasing in the number of hardened passes , dilution rate was reduced by the base metal and this cause to coarse and more uniform distribution of carbides .
This study aims to optimize the heat treatment of tool steel 75Cr1 which is used for heavy loaded elements in transmissions. A salt bath was used to quench and temper the steel at different temperatures. Mechanical tests and microstructural characterization were done to define the heat treatment parameters corresponding to the optimal performance of the elements. Optical microscopy, electron back scatter diffraction and x-ray diffraction were used to characterize the microstructure, while tensile tests and toughness tests were employed to determine the mechanical properties after different heat treatments. It was found that the yield strength decreases with increasing annealing temperature and that the toughness decreases with increasing annealing time and temperature. The changes of the mechanical properties are discussed in relation with the thermal treatment and the corresponding microstructures.
The analysis of stress-strain state of the bisector of the corner of the blank at a drawing of box-shaped parts. Analytical dependences for the meridional and circumferential stress on the bisector of the angle. It is shown that an increase in the limit drawing ratio compared with an extract of the cylindrical part is a consequence of the growth in absolute value of district compressive stresses. It was found that the maximum value of the coefficient of drawing of box-shaped parts cannot exceed the value of – K=exp(1+1/√3)≈ 4,84.
In the article is considered traffic management system in urban networks. Presented analysis of the criteria in the transport network management techniques. Showed results achieved in the implementation and management of traffic flows in the cities, their advantages and benefits. Development of mathematical dynamic models for calculating working parameters of the transport unit allows t create a well-functioning traffic management system. These systems allow to solve optimization problems, to regulate traffic flows in populated areas, thereby allowing the full potential of the existing route network, as well as it will ensure an adequate level of safety, convenience and efficiency of transportation with the least environmental impact.
REDUCTION OF EMISSIONS FROM OFF-ROAD HEAVY-DUTY DIESEL ENGINES USING CATALYZED DIESEL PARTICULATE FILTERpg(s) 50-54
Several different techniques and methodologies have been applied to reduce emissions from diesel engines. The main by- products of diesel engine combustion are carbon monoxide, carbon dioxide, total hydrocarbons, oxides of nitrogen, and particulate matter.
Diesel particulate matter and oxides of nitrogen are two of the most potentially harmful components of the diesel engine exhaust. Since 1990, the US Environmental Protection Agency (EPA) has been regulating off-road diesel emissions and imposing rules and standards on manufacturers and operators. The objectives of this study was to determine the mechanical durability of Diesel Particulate Filters (DPF) that are retrofitted on off-road heavy duty diesel engines, over prolonged periods of in-field operation and to assess the emission benefits of particulate catalyzed filter. The specific task was to evaluate the exhaust emissions from a Caterpillar 3408 engine on an engine dynamometer. Since the ability of the DPFs in reducing particulate matter (PM) emissions was of a prime concern, it was concluded that the DPFs are very effective in achieving up to 98% reduction.
INTERNATIONAL FORUM “A NEW SILK ROAD” AND PROSPECTS FOR DEVELOPMENT OF EURO-ASIAN TRANSPORT CORRIDORpg(s) 55-56
In view of the new realities created by signing the Association Agreement between Georgia and the European Union, Georgia for the first time was given the opportunity to be properly involved in the processes of global economic integration. This problem can be successfully resolved through safeguarding the Euro-Asian transport-communication space – “A New Silk Road”, and in the conditions of harmonizing the country’s geo-economic interests.
It should be noted that the first test train has passed already through the Georgian section of a new Baku-Tbilisi-Kars railway line.
This section is what should become a component part of “A New Silk Road”. The construction of 180 kilometers of this railway line has been already completed, and now everything is being done for completing all works by the end of 2015. This railway line is considered as the most significant project in the South Caucasus region of the Euro-Asian transport corridor.
When the internal combustion engine operates there are arising forces acting on the supporting elements, and by both value and sign they represent variable forces. They vary depending on time, depend significantly on load conditions of engine and are characterized by different vibro-frequency energies. These energies are unevenly distributed due to fact that the engine design comprises the elements having inertial, flexural and dissipative properties, frequency characteristics of which often vary within a wide range. The paper describes the method for determining frequency characteristic of vibro-energy transferred to the frame by introducing the vibro-energy transfer coefficient, which allows for determining frequency characteristics of vibro-energy transferred to the frame, on the basis of which, in turn, it becomes possible to determine efficiency of bearing shoes.
Information about non-motorized transport, i.e., cycling and walking, are needed for planning and management support of urban transport systems. However, in the city of Skopje, monitoring programs still aren’t established by transport officials on regular basis. Hence, transport planners and researchers lack bicycle and pedestrian counts for managing traffic demand. Having in mind principles for comprehensive monitoring as a framework for assessment, this paper summarizes approaches and recommendations for initiating monitoring program in the city of Skopje. Also, describes steps in establishing monitoring program and identifies possible application of the analyzed monitored data for non-motorized transport.