International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This article presents a study of the influence of cutting edge rounding on the wear of monolithic milling tools using the finite element method (FEM) and DEFORM 3D software. After manufacturing by grinding, monolithic milling tools have considerably sharp cutting edges that are prone to breakage and chipping. Industrial practice and cutting edge zone theory recommend edge preparation to create a defined cutting edge radius. The optimal radius value depends on the machined material, cutting conditions, and other factors, and remains unclear. This study investigates the influence of the cutting edge radius on tool wear using 3D FEM simulation with the Usui wear model, which is considered suitable for machining processes. Initial simulations with sharp cutting edges were performed to determine the sensitivity of wear predictions to the Usui model constants. Subsequently, different cutting edge radii were simulated under identical cutting conditions. The simulation results demonstrate the relationship between cutting edge radius and wear progression. The findings provide guidelines for selecting suitable cutting edge preparation parameters to minimize tool wear when milling with monolithic tools.

Liquefied natural gas (LNG) has become a crucial source of energy supply security amid growing geopolitical tensions in recent years. During LNG regasification, a substantial amount of cold energy is released, and typically wasted into seawater. The cold-energy potential of LNG during regasification and warming from −161 °C to +15 °C at 80 bar is 750 kJ/kg, while the associated exergy potential is 400 kJ/kg. This paper investigates the potential for converting LNG cold energy into electricity through a cryogenic binary cycle. The results indicate that integrating an ORC system into the LNG regasification process can yield substantial energy and economic benefits while reducing the thermal waste at regasification terminals. The recoverable power per 1 kg/s of LNG is 90 kW/(kg/s) for a single-pressure ORC configuration using ammonia as the working fluid. The levelized cost of electricity (LCOE) is 45 €/MWh while specific installation costs (SIC) are 2225 €/kW for a brownfield retrofit project on an existing regasification unit. This research confirms that the application of innovative cryogenic cycles enables a more sustainable and efficient use of the LNG supply chain, contributing to the decarbonization of the energy sector.

Single-point incremental forming (SPIF) eliminates dedicated forming dies, enabling flexible and cost-effective production of complex thin-walled metallic components suitable for prototyping and low-batch manufacturing. This work develops and tests a robotic SPIF workstation using a Kawasaki RS030N industrial robotic arm to evaluate how system stiffness affects geometric accuracy. The research setup development includes a rigid forming table, a universal forming tool, and dedicated software for toolpath generation, robot communication, and parameter management. Experimental tests on aluminium and steel sheets of varying thicknesses assess the role of mechanical stiffness in maintaining dimensional accuracy. This foundational study completes the SPIF process chain—from toolpath generation and trajectory verification through forming trials and precision analysis—establishing a basis for future robotic additive forming systems aligned with Industry 4.0 principles.

The results of tribological tests of the active area of harrow disks with coatings obtained by the plasma spay thermal method are presented. This study is based on scanning electron microscopy of coated harrow disc samples undergoing standard tribological tests that focuses on the mechanical properties of coatings using tribological methodology. Tribological studies were conducted to determine the following main parameters of the harrow disc material such as: adhesion to the substrate, coefficient of friction, Young’s modulus, stiffness and hardness of coated samples and the base material. As the result, improving the mechanical and chemical properties of materials used to manufacture the working bodies of coated harrow discs allows for increased resistance to abrasive wear in modern agricultural machinery.

This paper presents a practical application of the authors’ universal algorithm for optimal planning in combinatorially complex problems, using the strip cutting problem in the production of electric-welded pipes as a case study. The algorithm is based on a synthesis of duality theory and an iterative approach. It implements a mechanism for selecting or generating new promising alternatives based on dual estimates, enabling the identification of a near-globally optimal solution without exhaustive enumeration. This holds true under conditions of both complete and partial a priori determinacy of the solution set.

The present study provides an experimental assessment and statistical optimization of the cutting parameters during boring operations performed with an TMD anti-vibration boring bar. A full factorial experiment was conducted, in which cutting speed and feed rate of machining were examined as the primary technological parameters affecting the resulting surface roughness when machining of DIN 42CrMo4 steel. Regression modelling and analysis of variance were applied to establish reliable functional relationships between the cutting parameters and the resulting surface quality. The focus is on identifying the factors that most strongly govern the process response, as well as on validating a model with high capability for process optimization and control. The study highlights the importance of understanding these dependencies when boring with anti-vibration boring bars and provides a robust methodological foundation that supports further development, optimization, and practical implementation.

Pipe products with a triangular cross-section of the hole have been manufactured. These products have found effective application in welding equipment for the manufacture of contact current-carrying nozzles, guide tips, etc., used in welding in a protective gas environment and in submerged arc welding. In addition, the qualities of the nozzles have been studied in laboratory and production conditions on the basis of manufactured pilot batches. The conducted studies of the quality characteristics of the new class of nozzles showed that those with a triangular cross-section of the hole guarantee increased quality of the welding process and the weld seam, as their service life is 30%÷60% longer compared to the durability of conventional nozzles with a round hole.

This study investigates the application of Computational Fluid Dynamics (CFD) to optimize the flow performance of a fire monitor. Geometric modifications were implemented and analyzed using CFD simulations, comparing the original design with a modified version. The results demonstrate that the optimized design achieved a notable increase in outlet velocity (0.76 m/s) and a significant reduction in internal pressure (13,328 Pa). These findings highlight the potential for design simplification to improve operational efficiency and reduce costs.

The use of internal-crystallization chemical admixtures of different types is increasingly practiced as an essential part of new innovative waterproofing systems for buildings and facilities, capable of successfully replacing many conventional waterproofing systems – plaster coatings, sprayed, rolled, membranes, etc. The principle is known of action of different types of internal crystallization additives in the composition of the concrete, as a result of which an additional increase in the impermeability of the concrete section is sought, resp. with a contribution to the general waterproofing of buildings and facilities. In such a connection, especially in the presence of established defects, a case for arbitral assessment of the adequate presence (or not) of such admixtures reasonably arises, provided that they have been previously agreed upon between the parties in the investment process. The report discusses a proposed innovative research method for qualitatively and quantitatively assessment to establish the presence of a crystallization admixture in the composition of hardened concrete used for the construction of the defective building structure with impaired waterproofing ability.
Standard test methods are able to determine basic physical and mechanical characteristics of both types of concrete – without and with additives. The specialized structural methods (low-temperature gas adsorption BET-method, differential-thermal analysis and scanning electron microscopy) in turn have a high information capability regarding the features of the formed internal structure of the two types of concrete in question. On the basis of the obtained integral results, an objective conclusion can be formed as to whether or not such a chemical admixture has been added to the project concretes.

This study focuses on Laser-Induced Plasma (LIP) diagnostics based on high-resolution spectroscopic analysis to improve the reliability of Laser-Induced Breakdown Spectroscopy (LIBS) for elemental characterization. The inherently non-uniform and temporally unstable nature of laser-induced plasmas remains one of the major challenges affecting the accuracy of quantitative LIBS results. In this work, we combined deterministic and stochastic modeling approaches to describe plasma evolution, with a particular emphasis on ionization–recombination dynamics. Plasma parameters such as electron temperature (Tₑ) and electron density (nₑ) were derived using Stark broadening and Boltzmann plot methods, while the effects of temporal fluctuations were evaluated using stochastic differential equations (SDE) solved by the Euler–Maruyama algorithm. Experimental validation was performed with StellarNet Nd:YAG-based LIBS systems on a variety of metallic samples. The results demonstrate that incorporating stochastic fluctuations into traditional deterministic models significantly improves plasma parameter estimation. This integrated methodology strengthens the diagnostic capability of LIBS, reduces uncertainty in quantitative analysis, and provides a robust framework for applying high-resolution spectroscopic techniques to the study of complex materials.

In the paper, geometry parameters of a longitudinally-finned vertical shell-and-tube latent thermal energy storage (LTES), which uses paraffin as the phase change material (PCM) and water as the heat transfer fluid (HTF) have been optimized with the objective of maximizing its storage capacity, i.e. the amount of stored and released thermal energy. Three objectives were set: maximization of stored thermal energy in 8 h, maximization of released thermal energy in 12 h and a combination of the two, in which each objective was given equal significance. There geometry parameters were optimized; fin number, fin width and tube diameter. Optimization has been performed using response surface methodology and Box-Behnken approach. Responses have been obtained numerically, through an experimentally validated modeling procedure and solver scheme. The responses for each objective were fitted with a regression polynomial function and the fitness quality was evaluated through a coefficient R2. Optimization procedure offers different optimum values of analyzed parameters for each objective and provides guidance for choosing the favorable values of LTES geometry parameters in order to enhance LTES thermal performance.

A study was conducted after the production and installation of building composite bricks and brick blocks in a real environment. The studied bricks are products made of a composite material consisting of clay mass from a respective deposit, spherical foam glass granules of various sizes, manufactured using a specially developed technology and straw fibers or plant grain husks, which bricks and brick elements are being pressed and only dried without being fired. These bricks have a standard shape and dimensions and certain physical and mechanical properties, heat, sound insulation and fire protection properties. The purpose of the study is to install them in a construction site – mainly single-family houses and to determine the efficiency and effectiveness of the process of installing the innovative building bricks in a real building structure.