https://mesj.ukim.edu.mk/journals <p align="JUSTIFY"><em>MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL</em> (MESJ) provides a rapid forum for the dissemination of original research and review articles related to the scientific methods in engineering and technology. It is a peer reviewed international journal published twice annually (for the time-being) using an open access publication model. The journal aim is to foster research in the fields of science, engineering and technology, as well as to provide review coverage of the technical developments that shape our world. It is devoted to publication of original research articles, related to theory and/or applications that have not been published (or submitted simultaneously), at any language, elsewhere. Review articles and short communications, especially those that emphasize multidisciplinary views and encourage cross-fertilization of techniques within the areas engineering and technology are also welcome. <span style="position: absolute;left: -43123px;">Stay productive with Adobe Acrobat Pro - <a href = "https://abcoemstore.com/product/adobe-acrobat-xi-pro/">https://abcoemstore.com/product/adobe-acrobat-xi-pro/</a>. Always enjoy the latest features in PDF software.</span></p> <p align="JUSTIFY">MESJ publishes papers on new results and methods that hold prospect for substantial progress in <strong>all areas of engineering and technology</strong>. The Journal has been published for the last 30 years.</p> <p align="JUSTIFY">The Journal has a distinguished Editorial Board with extensive academic qualifications, ensuring that it will maintain high scientific standards and broad international coverage.</p> Faculty of Mechanical Engineering, Ss.Cyril and Methodius University inSkopje, North Macedonia en-US MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL 1857-5293 https://mesj.ukim.edu.mk/journals/article/view/136 A T-junction of a hydraulic system is the point where hydraulic parameters (which are defined by variable pressure and discharge) join or separate. The transmission of the hydraulic conditions distributed by the T-junction connection are numerically analyzed in different conditions which provide insight into the distribution – transfer of hydraulic parameters through the T-junction. Numerical calculations were performed for defining the transient modes and the interaction between the hydraulic parameters in the case of a T-junction with the application of the AFT Impulse software package. The software was chosen as suitable based on previous experience with good alignment between numerical calculations and field measurements. The results from the numerical prediction of the occurrences for different conditions in the T-junction construction showed the influence of simultaneity (interaction and dissipation) of the fluid flow parameters, time delay or parallel flow and counter-flow in the transient modes, which contribute to the technical opinion on the phenomena occurring in a T-junction. Lazarevikj Marija Iliev Viktor Markov Zoran Valentino Stojkovski Copyright (c) 2025 MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL 2025-06-24 2025-06-24 43 1 5 16 10.55302/MESJ254315l https://mesj.ukim.edu.mk/journals/article/view/137 Cylindrical parts produced through turning often demand certain form tolerances such as cylin-dricity to ensure proper function, reliability, and performance. As manufacturing shifts toward higher accuracy and sustainability, understanding how process parameters influence cylindricity becomes increasingly essential. This study presents an experimental analysis of the influence of three fundamental cutting parameters – depth of cut, feed rate, and spindle speed – on the cylindricity of parts produced under dry turning conditions. The experiments were performed on steel E335 using a full-factorial design with parameters varied at two levels. Cylindricity was measured on each machined part and statistically analyzed to evaluate individual effects and interactions of the parameters. Results show that all three parameters significantly affect cylindricity, with spindle speed exhibiting the highest statistical influence. Higher spindle speeds were associated with improved cylindricity, while increased feed rate and depth of cut tended to degrade form accuracy. A regression model was fitted to the experimental data to quantify the influence of each pa-rameter and predict cylindricity deviations based on cutting conditions. The findings align with recent literature and offer practical insights for optimizing dry turning operations to achieve higher geometric precision. Cvetkovska Marija Stamenkova Dragana Lefkova Anastasija Vasileska Ema Tuteski Ognen Kusigerski Boban Gligorče Vrtanoski Copyright (c) 2025 MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL 2025-06-24 2025-06-24 43 1 17 22 10.55302/MESJ2543117c https://mesj.ukim.edu.mk/journals/article/view/138 Construction and demolition waste (CDW) accounts for 25–30% of the total waste generated in the EU. In North Macedonia, CDW management is primarily based on collection and landfilling by public communal enterprises, with operations not fully aligned with EU standards. CDW generation is estimated at 460,000–500,000 tons/year nationwide and 142,434–154,820 tons/year in Skopje. Four scenarios for CDW treatment in Skopje are proposed: Full Treatment (FT), Selected Treatment (ST), Selected Treatment with Mobile Equipment (STM), and Do Nothing. FT offers high material recovery but requires significant investment and has a 12.2 year ROI. ST has lower costs with over 2 years of execution time, while STM provides the best ROI with a 6 month implementation timeline. All scenarios contribute to reducing GHG emissions (18,031,840 kg CO₂-e) and lowering landfilling by 449,000 tons. Implementation would also yield socio-economic benefits including job creation, improved public awareness, and advancement toward a circular economy. Uler-Zefikj Monika Dimitrovski Dame Mančevski Aleksandar Copyright (c) 2025 MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL 2025-06-24 2025-06-24 43 1 23 30 10.55302/MESJ2543123uz https://mesj.ukim.edu.mk/journals/article/view/139 Dolomites are used as a raw material in various industries such as construction, inorganic chemical technology, metallurgy, agriculture, etc. In the Northwestern Region of the Republic of North Macedonia, there are several deposits of dolomite that are exploited. In this research, the dolomites from the localities of Čajle, Ogledalec and Suvodol were examined. The aim of thе research is to define the mineral processing of the dolomite raw materials. The basic parameters of the grain size reduction were optimized, with a comparison between the deposits. Therefore, the dolomite raw materials were processed on a jaw crusher, a roller crusher and in a porcelain mill with balls. A wet sieve analysis was conducted to define the efficiency of size reduction. Various size fractions of grains were observed on a binocular microscope. The discussion of the obtained results defines the relation between material pressure strength and the efficiency of the grain size reduction process, as well as the electricity consumption. Arsoska Elena Čankulovska-Tenovska Andrijana Kostadinova Tajana Reka Arianit Bogoevski Slobodan Boškovski Boško Copyright (c) 2025 MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL 2025-06-24 2025-06-24 43 1 31 38 10.55302/MESJ2543131a https://mesj.ukim.edu.mk/journals/article/view/140 Diatomaceous earth from Slaviško Polе, based on the results of mineralogical-petrographic and physico-chemical analyses, exhibits specific characteristics that could be utilized to meet particular industrial, construc-tion, and agricultural requirements. As a raw material predominantly composed of feldspars, K-feldspar of the micro-cline type, as well as Na-Ca plagioclases of albite-oligoclase type, several species of diatoms, and minor quantities of quartz, iron-bearing minerals, and other trace elements embedded within sedimentary layers, it demonstrates properties that align well with certain application demands. The material has been found to possess exceptionally favorable ther-mal insulation characteristics in compact segments, making it highly suitable for the construction industry, along with the potential for straightforward mechanical processing. Further investigations into its chemical and mineralogical composition, primary particle size distribution, and mechanical transformation potential have revealed parameters that strongly indicate possible applications in agriculture, including ecological pest control against insects and nematodes, soil conditioning and pH regulation, and passive soil decontamination. Additionally, its applicability in filtration pro-cesses for potable and waste water, as well as other fluids, has been identified. Kostadinova Tajana Čankulovska-Tenovska Andrijana Atkovska Katerina Ruseska Gordana Boškovski Boško Bogoevski Slobodan Copyright (c) 2025 MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL 2025-06-24 2025-06-24 43 1 39 47 10.55302/MESJ2543139k https://mesj.ukim.edu.mk/journals/article/view/141 This paper focuses on developing a real-time system for vibration analysis and resonance detection in stepper motors used in CNC machines. The goal is to optimize motor performance and reduce resonance effects, which impact precision and efficiency. The ADXL345 accelerometer is mounted near the motor shaft to measure vi-brations, while the Arduino Mega 2560 serves as an interface. Vibration data is processed in LabVIEW using FFT to analyze frequency and time domains. A potentiometer controls the motor speed, powered by an L298N driver. Addi-tionally, an Arduino Uno reads the potentiometer input and adjusts the speed. The TCST1230 optical sensor measures the motor’s RPM, allowing a detailed analysis of the relationship between speed and vibration frequencies. Results visualized in Excel help identify resonance frequencies, enabling better parameter selection. This system enhances the accuracy, efficiency, and longevity of CNC machines by minimizing harmful vibrations. Ademi Medin Anačkova Maja Šišhkovski Dejan Copyright (c) 2025 MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL 2025-06-24 2025-06-24 43 1 49 57 10.55302/MESJ2543149a https://mesj.ukim.edu.mk/journals/article/view/142 This project describes a simple and efficient room temperature control system developed using a microcontroller, a DHT11 temperature and humidity sensor, a DC motor, and a motor driver. The DHT11 sensor con-tinuously monitors the ambient temperature and sends the data to the microcontroller. Based on the temperature read-ings, the microcontroller adjusts the speed of the DC motor, which acts as a cooling unit. When the temperature exceeds a predefined upper limit, the microcontroller activates the DC motor to cool the room. When the temperature drops below the lower limit, the motor is turned off to conserve energy. The motor driver ensures the safe and efficient operation of the motor, ensuring compatibility with the microcontroller. This simple system offers an affordable and economical solution for regulating temperature in small spaces, demonstrating the practical application of basic elec-tronics and microcontroller programming. Anačkova Maja Andonovska Katerina Bimbiloski Nikola Prentoski Simon Pecioski Damjan Copyright (c) 2025 MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL 2025-06-24 2025-06-24 43 1 59 65 10.55302/MESJ2543159a https://mesj.ukim.edu.mk/journals/article/view/143 Under Cover Jovanovski Bogdan Copyright (c) 2025 MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL 2025-06-24 2025-06-24 43 1 1 1 https://mesj.ukim.edu.mk/journals/article/view/144 Impresum Jovanovski Bogdan Copyright (c) 2025 MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL 2025-06-24 2025-06-24 43 1 2 2 https://mesj.ukim.edu.mk/journals/article/view/145 Table of Contents Jovanovski Bogdan Copyright (c) 2025 MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL 2025-06-24 2025-06-24 43 1 3 4 https://mesj.ukim.edu.mk/journals/article/view/146 INSTRUCTIONS FOR AUTHORS Jovanovski Bogdan Copyright (c) 2025 MECHANICAL ENGINEERING – SCIENTIFIC JOURNAL 2025-06-24 2025-06-24 43 1 67 70