Machines. Technologies. Materials.
Vol. 18 (2024), Issue 6

Table of Contents

  • MACHINES

    • Green Transformation in Energy Recovery: A Modular Approach to Flue Gas Waste Heat Exchangers for ORC Systems

      pg(s) 183-184

      This study focuses on the development of modular flue gas waste heat exchangers designed for integration with organic Rankine cycle (ORC) systems within the cement industry. The design and implementation of this system involved comprehensive engineering analyses to address challenges like corrosion and thermal stratification. These heat exchangers, the first of their kind to be produced in Turkey, are compatible with Industry 4.0 standards and offer the capability to convert waste gases into electrical energy without the need for water. This pioneering technology plays a significant role in promoting eco-friendly industrial practices by reducing carbon emissions and supporting the transition to greener energy solutions.

  • TECHNOLOGIES

    • The impact of high voltage electric discharge treatment in ethanol on the dispersity and phase composition of Cu – Al powder mixture

      pg(s) 185-188

      Studies of the impact of high voltage electric discharge (HVED) treatment on the dispersion and phase composition of 87,5 % Al + 12,5 % Cu powder system were performed. It was shown that HVED treatment in ethanol with specific treatment energy of 5 MJ/kg leads to the decrease of mean diameter of treated powder from 15 to 11 μm, and the increase of specific treatment energy to 20 MJ/kg leads to the decrease of mean diameter of treated powder from 15 to 6 μm. X-ray diffraction analysis shows that CuAl2 and Al4C3 are synthesized in all considered treatment regimes, and the quantity of these phases depend on the specific treatment energy.
      The use of “three point – plane” electrode system instead of “point – plane” during HVED treatment of 87,5 % Al + 12,5 % Cu powder system in ethanol leads to the increase of quantity of synthesized Al4C3 and CuAl2 phases with the slight decrease in the dispersion efficiency.
      Up to 35% of particles in powder mixture, treated by HVED in ethanol with the use of “three point – plane” electrode system, have diameter close to the diameter of the initial powder mixture.
      It is shown that the preparation of powders with an initial composition of 87.5% Al + 12.5% Cu using HVED treatment in kerosene or ethanol with subsequent consolidation by SPS method allows obtaining metal-matrix composites of the Al – Cu – C system with increased indicators of hardness, electrical conductivity and wear resistance.

    • Laser-pulse thermal strengthening of injection molds and dies in the production of semiconductor device packages

      pg(s) 189-192

      In the production of integrated circuit packages, the process of laser monopulse thermal strengthening with beams of special geometry has been researched, developed and implemented to increase the durability of dies for the production of flanges, injection molds, housing rim calibration dies, and automatic stamps for the production of integrated circuits. Laser pulse hardening modes for stamp parts and injection molds have been established. A necessary condition is the presence of a laser emitter, which, according to its technical parameters, allows one to obtain a pulse energy sufficient for thermal strengthening of the contour of the working edges of the part. In order to prevent undesirable effects on the working edges of technological tool parts, a theoretical model of the hardening process has been developed, which allows for the calculation and optimization of laser processing modes to obtain the required operational properties of steel based on a preliminary calculation of temperature fields.

    • Finite Element Method (FEM) Model Development for Cutting Process Simulation Using Mentat and Marc Solver

      pg(s) 193-196

      This study presents the development of a Finite Element Method (FEM) model to simulate cutting processes, focusing on the analysis of various parameters such as stress, strain, temperature, and cutting forces in the cutting zone. The FEM model is developed using Mentat software and solved with the Marc solver. By employing this method, we can effectively manage cutting parameters, optimize cutting tool geometry, predict tool wear, and improve tool life. The research investigates key parameters and their values, providing insights into the cutting process that can enhance efficiency and performance. The application of FEM in this context offers a robust framework for advancing the understanding and development of cutting technologies. Various software applications that support these investigations are also explored, underscoring the versatility and precision of FEM in cutting process simulations.

    • Synthesis and characterization of nanostructured coatings on glass from oxides of transition elements with the participation of Eu2O3 obtained by sol-gel technology

      pg(s) 197-200

      Obtained experimental self-cleaning coatings (based on compositions with the participation of Eu2O3), applied by the solgel method on glass slides. This study attempts to improve the overall efficiency of a photovoltaic solar panel by using a ZrO2-based coating, with Y2O3 and addition of Eu2O3. The optical characterization and phase composition of the obtained experimental samples were investigated using UV-VIS-NIR, XRD and XRF methods. The coatings are nanocrystalline according to XRD and XRF analyzes and show transmittance close to that of pure glass when tested with a UV–VIS–NIR spectrophotometer The experimental results represent a prerequisite for the development of a series of additional compositions and a detailed technological regime for obtaining various modifications of resistant, long-lasting self-cleaning coatings, potentially applicable to photovoltaic panels.

    • Innovative paper for innovative graphic products

      pg(s) 201-202

      In recent years, constantly changing global conditions and the increasing use of digital media have significantly impacted the printing industry, causing almost a complete transformation in this field. Newspaper circulations are declining, a trend substantially accelerated by the pandemic. On the other hand, the demand for paper or cardboard packaging increased during the pandemic, showing a promising future. The largest and fastest-growing market for corrugated cardboard is China, with its rapidly growing middle class and ecommerce giants. Prices of wood fibers, the primary raw material for paper production, have risen in recent years. This is due to various factors such as environmental regulations and so on. Rising energy prices have significantly contributed to the increase in production costs. Due to the rising prices of wood fibers, the APPLAUSE project was initiated, where papers and cardboards were made from invasive alien plants: Japanese knotweed (Fallopia japonica), Canadian goldenrod (Solidago canadensis), and Black locust (Robinia pseudoacacia), as well as waste tomato stems (Solanum lycopersicum). All produced materials were also practically tested with various prototype products.”

    • Morphology of vacuum coatings based on compounds AlTiSi(CN).

      pg(s) 203-206

      The article examines the morphology of high-entropy coatings formed using vacuum technologies on low-carbon steel substrates. Studying the morphology of the surface layers of TiAlSi (N ,C ) coatings formed on low-carbon steel substrates using atomic force and optical microscopy methods made it possible to establish the dependence of the morphological parameters of the coatings on the energy parameters and chemical composition of the substrate. The dependence of the morphological parameters of coatings on the conditions for the formation of vacuum layers on low-carbon steel substrates is also shown.

  • MATERIALS

    • Thermodynamic properties of melts of binary and ternary systems containing Fe, Mn, Si or Ti

      pg(s) 207-209

      The thermodynamic properties of the melts of the Fe–Mn(Ti)–Si, Fe–Mn–Ti, and Mn–Si–Ti ternary systems at 1873 K were studied using the “geometric” and “analytical” Redlich-Kister-Mujian models from reliable analogous data for binary boundary subsystems. Special attention is paid to the precise thermodynamic properties of melts of the Fe-Mn, Fe-Si, and Mn-Si systems, with analysis of new data for the Si-Ti, Fe-Ti, and Mn-Ti systems. Very negative deviations from ideal solutions were established for the activities of the components in melts of the Fe-Mn-Si system. In the melts of the Fe–Mn(Ti)–Si, Fe–Mn–Ti, and Mn–Si–Ti ternary systems, the minimum mixing enthalpies are observed in binary melts, and in the Fe–Mn–Si system, the minimum occurs in the Fe0.4Mn0.2Si ternary melt 0.4, because the double Fe(Mn)– Si subsystems make the largest contribution to the interaction energy between different atoms. This study demonstrates the ability to predict the thermodynamic behavior of ternary systems, allowing for optimization of alloy compositions and improvement of industrial processes. Calculations based on the Redlich-Kister-Mujianu model with a triple contribution of -200 kJ/mol for melts of the Fe–Mn–Si system agree with experimental data, which confirms sufficiently high accuracy predicted parameters.

    • Synthetic diamond grinding powders with increased abrasive ability for grinding tools

      pg(s) 210-211

      The results of a quantitative study of the influence of methods of chemical cleaning, pulse treatment with high-voltage electric discharges in a liquid, and flotation separation of synthetic diamond powder of the AS20 grade with a grain size of 100/80 on its abrasiveness are given. It has been established that the use of pulse treatment with high-voltage electric discharges in a liquid provides selective destruction of low-strength diamond particles, activation of the energy state of the surface, and an increase in abrasiveness. Changes in powder characteristics: homogeneity in strength by 1.3-1.9 times; decrease in the mass fraction of impurities by 2.8-7.8 times; guarantee an increase in abrasiveness up to 30-34% and contribute to the improvement of the physico-mechanical and physico-chemical characteristics of synthetic diamond powder

    • A new approach to densification of titanium-based hard composites reinforced by TiВ

      pg(s) 212-214

      Titanium–titanium boride (Ti/TiB) metal matrix composites have been widely identified as promising materials for various applications. The traditional ingot metallurgy processing strategies used to fabricate these materials are energy intensive and have fallen short of their perceived mass production potentials. Powder metallurgy processing, especially that aimed at in-situ synthesis of Ti/TiB composites from titanium and TiB2 powder blends, is currently widely used for the cost-efficient production of such composites. Additional processing by the method of hot pressing improves the structure and mechanical properties of this class of materials.