|
This issue of the RECENT journal was edited with the support of: CONTENTS
Theoretical and Experimental Research on Thermal Field Mathematical Modelling during Welding Load Operations on Active Surfaces of Milling and Cutting Teeth Used for Road Top Strippinghttps://doi.org/10.31926/RECENT.2021.65.104 Abstract The ever-increasing number of vehicles on the roads has created the need to expand or rehabilitate the road infrastructure, and milling and cutting drums used for road top striping play a major role in these operations. The main components involved directly in the structure dislodging and milling process are their teeth. A tooth is basically made up of the body itself and a tungsten carbide tip that is fastened by brazing. There are currently various teeth manufacturing processes, but for our paper we chose a manufacturing process consisting of welding loading of the active part of the tooth. Under these circumstances, the brazing area may be thermally impaired. The studies described in our paper refer to the analysis performed using the finite element method of the thermal field distribution in the brazing area of the tungsten carbide tip in the cylindrical hole at the front of the tooth body, to checking the theoretical determinations made by mathematical modelling and to analysing the way in which the welding processes used thermally affect the critical target area the most. Keywords milling and cutting drum tooth, welding, brazing, thermal field, mathematical modelling
Digital Platform for the Optimization of Occupational Health and Safety Systems Specific to the Industrial Area - Part Ihttps://doi.org/10.31926/RECENT.2021.65.111 Abstract In Romania there was a long period of time in which the activity of the occupational health and safety system (OHS) was regulated. Over the time, it became mandatory to fill in the instruction material exclusively by hand. As a result, it proves to be absolutely necessary to optimize the activity of the process of management of the documents corresponding to occupational health and safety systems. This was done by means of our online application SSM.RO. The purpose of the study is to evaluate the efficiency and the accessibility level of this application. The main method was a questionnaire that was applied to 246 respondents. The results of this questionnaire were analysed by means of Fisher's exact test. The most statistically significant association was observed between the highest successfully completed level of education (which can be university or high school) and the level of accessibility of the application SSM.RO. We also observed a relationship between the highest successfully completed level of education of the employees and the way in which employees acquired knowledge for the use of the Internet. It is very important that more than 91% of the respondents expressed their willingness to have the future trainings in an online environment since the application SSM.RO was considered intuitive and easy to use. Keywords digital platform, optimization, occupational health and safety
Comparison of Expansion Properties of Hot Water Valve from Three Different Materialshttps://doi.org/10.31926/RECENT.2021.65.119 Abstract Polyamide stoiren acrylonitrile (SAN), polyamide 6.6 (PA66) and polymethyl methacrylate (PMMA) are three different materials considered as a possible alternative instead of hot water valve, produces by the company through conventional method by plastic injection machine. The goal of this paper is to propose the most suitable alternative among the three ones, using the examination of the thermal expansion coefficient and study the characteristic implication of different air pressure and temperatures simultaneously. The study was conducted with the specific designed experimental assembly and strain gauge software. The experimental results advise PA66 material as most suitable alternative of brass hot water valve. Keywords CuZn40Pb2, polyamide 6.6, stoiren acrylonitrile (SAN), polymethyl methacrylate (PMMA), strain gauge, expansion
Study on the Application of the Bowtie Methodology for the Assessment of Ergonomic Risks in the Industrial Fieldhttps://doi.org/10.31926/RECENT.2021.65.128 Abstract Background and objective: Bowtie Analysis is an advanced risk assessment tool that allows users to view the risk map and illustrate the pathways from their causes to potential effects. In addition, the Bowtie analysis allows the assignment of controls for each identified cause and the application of key risk indicators, to help track the performance of risk controls. The aim of this research is to assess the risk of injury or damage to health for workers who are exposed to ergonomic risks, using the Bowtie methodology. Methods and materials: This paper presents an applied study of the Bowtie methodology, a proactive and systematic risk assessment technique, for the analysis and assessment of ergonomic risks in the industry. In this paper, a semi-quantitative method BTRA (Bowtie Risk Assessment) of estimating and evaluating the ergonomic risk was used, the method having the results of the Bowtie diagram as input data. The research analysed the activity: welding metal parts, an activity associated with "danger" because it generates many risks of injury and damage to workers' health. Results: Analysing the results of the assessment of the ergonomic risks generated by incorrect and/or uncomfortable positions during the activity of welding of the workpieces in the production hall, it is found that there is a high probability of occurrence of musculoskeletal disorders but also of serious injury to the worker caused in particular by the non-use of the appropriate means of working at height/semi-height and the use of improvisations, as well as due to the lack of mechanized means for gripping and rotating the workpiece in a position favourable to the worker. Conclusion: Analysing the results obtained in this paper, it can be concluded the following most important findings, such as: The Bowtie methodology has proven its efficiency and effectiveness in identifying causes and effects in the event of occurrence of a Hazardous Event (Top Event) and the BTRA assessment method is easy to use in combination with the Bowtie method, taking into account the causes and consequences and assessing the effectiveness of proactive and reactive barriers, then classifying the criticality of causes and effects and finally estimating the probability and severity values based on which the risk is assessed. Keywords ergonomics, risk assessment, bowtie methodology, musculoskeletal disorders
How and Why to Manage 3D Printing Process?https://doi.org/10.31926/RECENT.2021.65.137 Abstract The present paper is focused on identify the main conditions that should be followed to obtain an optimum three-dimensional (3D) printing, starting with the 3D design software, to printers and characteristics. The purpose of the analysis is to be able to develop an informatic instrument, designed for choosing the appropriate 3D printing characteristics, printers and materials based on the purpose and industry of the printed part. Because the input data are very diverse, with multiple options and the user either has one specific printer, or want a specific material, authors implement fuzzy logic in obtaining the optimum. Since there is no such software on the market, it is believed that the informatic application developed by authors can help the decision makers about their 3D printing process. Keywords 3D printing, printer, Industry 4.0, fuzzy logic
Research on the Concept of Antifragility in Project Management Applied in Industry 4.0https://doi.org/10.31926/RECENT.2021.65.145 Abstract This study summarizes the analysis of how the concept of fragility could be applied in the industrial environment through project management, as well as the emphasis on the methods of adaptation of an organization in response to changes in environmental conditions, so that it can absorb the shock and sometimes even to progress in conditions of uncertainty. For the industrial field, the application of specific antifragility concepts in project management can generate a greater capacity for adaptability to changes in external environmental factors and thus a much more stable growth over time - especially in the light of Industry 4.0 challenges. In this regard, this paper makes several proposals and interpretations of these decision-making mechanisms. The natural conclusion leads us to the fact that the concept of antifragility can be extended, both theoretically and practically, in the field of industrial management. Keywords project management, antifragility concept, decision substantiation, systems adaptability, management of the industrial projects
Estimating the Water Loss Volume in an Experimental Installationhttps://doi.org/10.31926/RECENT.2021.65.151 Abstract The paper presents a study on the sensitivity of the water meters and on the volume of the water loss in a water supply branch, corresponding to a block of flats, aiming to emphasize ways in which errors in metering the consumed water are produced. It is presented also the experimental installation used in the research, which consists of several water meters of different types, used as apartment water meters and branching water meters. The water meters analysed are of three types, belonging to two different precision classes. Data analysis was performed on data collected from the water meters considered. The experimental installation is used for collecting experimental data, for determining the water loss volume; it also analyses the water loss estimated for a month for each water meter considered, creating the premises for estimating the water loss volume during a certain period of time for a block of flats consisting of a certain number of apartments, assuming that there are the same type of water meters mounted in each apartment. In this way it is possible to determine the losses in a potable water supply system. Keywords water flow, water meter, water loss volume
|
|
