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This issue of the RECENT journal was edited with the support of: ContentsAnalysis of the quality of squirrel cages rotor machined at Electroprecizia Electrical Motors
RECENT J. (2022), 68:092-099 https://doi.org/10.31926/RECENT.2022.68.092 Abstract The paper presents methods for improving the quality of rotor squirrel cages in the casting phase at Electroprecizia Electrical Motors Săcele. For this purpose, there are analysed the results of theoretical and experimental research on the existing interdependencies between the quality of rotor squirrel cages obtained by casting and the metallurgical quality of aluminium melts, respectively the parameters of the casting process. When balancing rotor squirrel cages, the non-homogeneity of the compactness of the cast aluminium mass raises a number of technological problems. This non-homogeneity of the compactness is determined by the presence of voids (bubbles, pores) in the cast material. However, the compactness of the aluminium mass (the voids in the cast aluminium) has a decisive influence on the electrical efficiency of the electric motor due to the drastic local modification of the electrical resistivity. Based on an analysis of the results obtained, there can be concluded that the development of a new family of electric motors, of super premium energy efficiency class (IE4), also involves the analysis and detection of the causes that lead to the formation of bubbles and pores in the cast aluminium mass, on the current process flow, subsequently reducing them by improving the existing technologies or even by replacing them. Keywords pressure casting, aluminium, rotor squirrel cages, micro-shrinkages, quality analysis An Analysis of the Possibilities to Develop and Implement a Modular and Scalable System Based on Mini-Aerial Robots for Precision Agriculture
RECENT J. (2022), 68:100-106 https://doi.org/10.31926/RECENT.2022.68.100 Abstract The paper presents an analysis of the possibilities to develop and implement a modular and scalable system, based on mini aerial robots for precision agriculture. The recent developments in the field of UAVs (unmanned aerial vehicles) have created new applications in new domains of interest. The technological progress at electric engines, batteries, multispectral sensors, and communications opens new directions also in the field of precision agriculture applications. The interest is now to evaluate the opportunities and risks to develop and implement a new generation of a scalable integrated aerial system dedicated for activities in the field of precision agriculture. The focus is on the possible performances but also on qualitative intangibles including the costs on the entire life cycle of these systems. The typical modular and scalable system based on mini- aerial robots for precision agriculture is based on three critical sub-systems capable to work synergistically and that capture the advantages of the recent disruptive technological innovations. Keywords unmanned aerial vehicles (UAV), mini- aerial robots, precision agriculture, scalable system, modular system Method of Water Filtration Using Ceramic Composite Materials Based on Bentonite
RECENT J. (2022), 68:107-111 https://doi.org/10.31926/RECENT.2022.68.107 Abstract This paper presents a method of water filtration using composite filters based on bentonite powder, alumina ceramic particles and iron metal particles. The base of the composite material was developed from bentonite and alumina ceramic particles. Various percentages of iron metal particles were added to the base matrix of the composite and there were obtained several groups of materials. They were compacted in a metal mould to make cylindrical raw material samples. The samples were sintered at 1100 °C. There were obtained ceramic filters of Φ = 16 mm diameter and 14-16 mm high. In order to meet the purpose of the research, the ceramic filters were characterised in terms of compressive strength and there were determined some dependencies between their structure and properties. A laboratory installation was used to demonstrate the filtration of the solid components from water by means of CWF composite filters. Both parts of the filter were subjected to the action of the pressure generated by the centrifugal pump within the installation, which led to the displacement of the fluid. There was demonstrated the ability to retain the solid components in water by means of these ceramic composite filters. Keywords bentonite, ceramic filter, metal particles, ceramic composite materials Pack Carburizing Effect on Microstructure and Hardness of 1.7131 Steel
RECENT J. (2022), 68:112-117 https://doi.org/10.31926/RECENT.2022.68.112 Abstract Pack carburizing technology was used for case hardening of 1.7131 steel at 930 ºC in different condition. Effects of holding time (2-, 4-, 6- hours), quenching environment (air, water) and annealing temperature (170 ºC) on microstructures, case and core hardness were investigated. All samples were characterized by the appearance of four zones with different morphology (intermetallic compound, hypereutectoid, eutectoid and hypoeutectoid), caused by carbon diffusion and quenching parameters from the carburizing temperature. An adapted setup of pack carburizing holder was performed to apply direct water quenching. Carbon distribution was calculated using Fick’s law and effective case depths were identified, agreeing with the measured hardness values. The most significant hardness values were measured at approximatively 0.5 mm depth 55-65 HRC (590-850 HV). Depending on holding time, high hardness values were recorded also after 1 mm case depth. The advantages of using pack carburizing for low-carbon or low-alloy steels are the low-cost processing and the combination of high surface hardness and high core toughness needed in the parts durability. Keywords pack carburizing, 1.7131 steel (16MnCr5), diffusion, carbon distribution Quality Management for Industrial Projects
RECENT J. (2022), 68:118-122 https://doi.org/10.31926/RECENT.2022.68.118 Abstract Project quality management includes the processes necessary to ensure that a project meets the requirements for that it was undertaken to. Considering these aspects, this paper highlights the role of quality management in industrial projects and its integration within the specific project management processes. Thus, the study refers to the implementation of quality management within an industrial project with the detailed specification of the input data, the appropriate methods, as well as the analysis of the results, with the aim of achieving the project's objectives. Keywords project management, project quality management, industrial project, Deming cycle Industrial Robots in the Era of Digitalization: Validation of Structures
RECENT J. (2022), 68:123-130 https://doi.org/10.31926/RECENT.2022.68.123 Abstract Large Scale Optimization is a very well-known concept in the context new manufacturing era. There are many applications focused on supply chain and intelligent or smart manufacturing. As part of flow optimization is substituting some workplaces with robotic structures (industrial robots, manipulators, cobots, etc.). Thus, one challenge is to get a good process design, with optimum systems use, with business impact, return of investment (from financial and human resource point of view). Another challenge is to choose the kinematic structure oriented on station’s requirements. The robots are particular form of automation with significant costs that increase with the number of joints. But, in the context of Industry 4.0 revolution the use and design of robots and kinematic chain workstations it changes. Keywords manufacturing, optimization, robot, cost reduction, efficiency Automation of assembly processes
RECENT J. (2022), 68:131-137 https://doi.org/10.31926/RECENT.2022.68.131 Abstract Large-scale manufacturing companies use larger automated assembly processes including the use of heavy robotic equipment to put together large products, such as automobiles. The assembly lines in these systems have centralized control, operated by only a few workers. However, the lines, as production elements, are independent in the assembly process. Automated assembly systems are designed to perform assembly operations in a fixed manner product assembly sequence. Four types of systems/operational planning problems are significant: delivery of parts to workstations; single station system; automatic multi-station systems; and partly automation. This paper focuses on the multi-station automated system used for operational assembly. Keywords automated assembly systems, Industry 4.0, performance analysis Analysis of the Water Loss Volume in a Real Installation
RECENT J. (2022), 68:138-141 https://doi.org/10.31926/RECENT.2022.68.138 Abstract The paper presents an analysis of the ways in which errors in metering the consumed water are produced. The analysis is performed on data obtained by recording the water consumption in each apartment from a block of flats, during several months, and also, by considering the total volume of water indicated by the branch water meter, the one indicating the water consumption for the entire block of flats. Also, the paper contains a study on the sensitivity of the water meters mounted in the apartments from the block of flats considered and on the volume of the water loss in the respective water supply branch, corresponding to the block of flats. The study is aimed to emphasize ways in which errors in metering the consumed water are produced. The paper presents the experimental installation used in the research, which consists of several water meters of the two different types, of the same precision class, which are mounted in the apartments from the block of flats. Data analysis was performed on data collected from the water meters considered, in order to establish the water loss volume, such as to analyse the water loss estimated for a month for each type of water meter considered. In this way, it is possible to estimate the water loss volume for a certain period of time for the block of flats considered and, by that, to find ways to prevent losses in the potable water supply system. Keywords water flow, water meter, water loss volume
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