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This issue of the RECENT journal was edited with the support of: CONTENTS
Making Machining Process More Efficient by Optimising the Tool Replacement Regimehttps://doi.org/10.31926/RECENT.2021.64.062 Abstract As known, all industrial companies from all over the world are aiming at the main objective, as to maximize their profit. In order to reach this objective, companies use certain strategies, principles and techniques. An important strategy regards the optimisation of the available resources, including material, financial, human, and informational resources. Companies must also pay an important attention to their technological processes that include certain machining processes for obtaining the products to be delivered to the marketplace. The present paper is focused on the optimisation of the cutting tool changing regime, which represents an important part of the lead time, in order to make the machining process more efficient. The core of the paper regards the optimisation of multi-tool life and machining parameters so that the time of tool change is diminished. The paper also includes two case studies that refers to drilling process using multi-tool machining. Keywords Tool replacement, multi-tool machining, machining parameters optimization, tool life, twist drill
Procurement in Automotive Industryhttps://doi.org/10.31926/RECENT.2021.64.069 Abstract The automotive industry is certainly one of the largest and dominant industry in the world being highly dependent on supply chains management. Customer requirements and technological development are changing rapidly so the need of automation in supply chain management is unavoidable. Procurement in automotive industry it is a key process closed linked with product management and production. The transformation generated by industry 4.0 is also pushing procurement to next level of automation adding value chain truth cost reductions, transparency, and smart contracts. Global semiconductors shortage generated disruption in automotive industry supplies chain management and high sales decreases with important profit loses. The study aim is to determine procurement best practice for sustainable and efficient supply chain. In future procurement department should play a fundamental part in innovation management by focusing on efficiency and automation of operation tasks including negotiations. It is recommended to have long term strategies regarding good relationship between tier suppliers and smart contracts with OEM. Keywords procurement, supply chain management, automotive industry, suppliers, OEM, industry 4.0
Classification and Review of Hand Rehabilitation Deviceshttps://doi.org/10.31926/RECENT.2021.64.074 Abstract The aim of this study is to provide a general insight into the causes and mechanisms that lead to hemiparesis while also providing insight into how the condition can be ameliorated or even treated. For the scope of this study, the only treatment methods considered were the ones using robotic rehabilitation devices as opposed to classical methods, such as kinesiotherapy and, where available, provide a comparison between the two. To form a clearer picture of the different types of rehabilitation devices, a classification method based on the device`s interaction with the patient, the type of actuator and it`s stiffness is introduced, and different examples are provided along with available specifications. The study further compiles data on the development of soft robotics rehabilitation devices and emphasises the effectiveness and adaptiveness of said devices and highlights the importance of additional research in this field. Keywords rehabilitation equipment, hemiparesis, soft robotics
Analysis of the Metrological Reliability - Study on Simulated and Experimental Datahttps://doi.org/10.31926/RECENT.2021.64.081 Abstract The paper presents an algorithm for simulation of the parameter deviation. The case of a normal distribution function is considered, due to the fact that normal distribution is met frequently in the reliability analysis. The aim of the simulation of the parameter deviation is represented by the determination of the calibration life of the measuring devices as a function of the metrological reliability, by means of the parameter deviation functions. The algorithm constructed for determining the calibration life based on the parameter deviation was first checked in case of simulated data an then it was used for experimental research. The paper also presents the results of experimental studies conducted on specific mechanical measuring instruments - external micrometres for 25 - 50 mm and external calliper rules of 150 mm with depth rod and with a resolution of 0.1 mm. The aim of the study is to determine the calibration life of the considered measuring devices as a function of the metrological reliability, by means of the parameter deviation function and then to compare it with the pre-set calibration life stated in the appropriate standards. Keywords metrological reliability, parameter deviation, normal distribution
Public Awareness and Perception of Renewable Energy and Systems and Related Educational Needs in Turkey and Bulgariahttps://doi.org/10.31926/RECENT.2021.64.086 Abstract This study analysed the awareness and perception of individuals in Bulgaria and Turkey on the topic of renewable energy (RE) and the need for education about it. The study was carried out in order to provide an infrastructure for developing training modules at each educational level. A survey of public perception, awareness and lack of information was given to a total of 453 participants from Turkey and Bulgaria and the results were evaluated using the difference analysis method and SPSS software. Evaluation of the results obtained from Bulgaria and Turkey showed similar findings in terms of the general trend for the various topics. In both countries there was an awareness of RE that cannot be underestimated. However, along with this, the RE awareness and perception decreased as the subject turned from theoretical concepts to technical details. In other words, the technical knowledge was insufficient to support the perception and awareness that existed at the level of the general culture. The results of the study revealed that educational planners and concerned parties should give more emphasis in their studies to awareness and perception of the topic to be established through educational institutions and via the media. Keywords perception, awareness, renewable energy, educational needs
Studies on the Wear Behaviour of High Chromium Alloy Steelshttps://doi.org/10.31926/RECENT.2021.64.093 Abstract There was studied a steel highly alloyed with chromium, with an average carbon content. The research aimed to highlight the influences of various heat and thermochemical treatment operations on the wear resistance. 40Cr130 has multiple uses in practice, and in many of them the products are subject to intense mechanical stress and wear. There were performed quenching operations followed by tempering at several temperature and time variants. Ionic nitriding operations were also performed. On samples of the given steel, the wear resistance was determined using the Pin-on-disk method, highlighted by the dynamic friction coefficient µ and the wear coefficient K. Keywords chromium alloy steels, wear behaviour, heat and thermo chemical treatment
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