The paper presents the results of a students’ survey carried out at “Vasile Alecsandri” University of Bacau, Romania, on the quality of educational process on online platforms in the context of the COVID-19 pandemic. The study was addressed to students from the Faculty of Engineering and the Faculty of Physical Education and Sports. The results of survey highlighted that most of students were satisfied with the measures taken by the university during the lockdown period and the way the teaching—learning-assessment process took place. However, some negative aspects were reported as: lack of an adequate infrastructure for some students, less effective teacher-student communication and interaction, impossibility of performing practical applications, lack of socialization, lack of learning motivation, less objective examination (e.g., possibility of cheating), possibility of physical and mental health degradation (e.g., too much time spent in front of screens, installation of a sedentary lifestyle). Consequently, for the new academic year, effective, and efficient measures must be implemented by the management of the university to remove, as much as possible, these negative issues and to improve the performance of online educational process.
<p>The aim of the current work was to analyse the influence of the process parameters (tool diameter, size of the vertical step of tool, feed rate and spindle speed) on the quality of the processed surface, expressed in terms of roughness and macrostructure in the case of parts processed by single point incremental forming. The analysis was made on A1050 aluminium metal sheets. The obtained results revealed that the process parameters influence differently the surface quality, the worst influence being exerted by the increase of the vertical step of tool. </p>
One main drawback of electrical discharge machining (EDM) is related to the dielectric fluid, since it impacts both the environment and operator health and safety. To resolve these issues, recent research has demonstrated the technical feasibility and qualitative performance of vegetable oils as substitutes for hydrocarbon-based dielectric and synthetic oils in EDM. However, due to the higher content of unsaturated fatty acids, vegetable oils lose their stability, due to several factors such as heating or exposure to light or oxygen. The present study is a first attempt to analyze the extent to which the physic-chemical properties of vegetable oils change during EDM processing. Refractive index, dynamic viscosity and spectra analyses were conducted for sunflower and soybean oils. The results revealed that, under the applied processing conditions, no structural changes occurred. These findings are very promising from the perspective of EDM sustainability.
Abstract. The aim of the current paper is to determine the influence of material thickness on the quality aspects of AWJ processing of the AL6061T651 alloy. The analysis is performed under different working conditions. The parameters taken into account to quantify the quality of processing are those defined in the ISO/WD/TC 44 N 1770 standard: width of the processed surface at the jet inlet (Li), width of the processed surface at the jet outlet (Lo), deviation from perpendicularity (u), inclination angle (Į) and roughness (Ra). The obtained results emphasise a significant influence of material thickness on both, the surface quality and process productivity.
Abrasive water jet processing is one of the newest unconventional technologies. It can be used to cut different metallic materials (steel, titanium alloys, aluminium alloys, brass) or non-metallic materials (wood, plastics, glass, stone, granite etc.). Therefore, this technology can be successfully applied in different industries as: food industry, wood industry, aeronautic industry, automobile industry, mining industry. Between the advantageous of abrasive water jet processing technology it is worth noticing the following: it is rapid, very small processing forces are generated, it is silent, no thermal distortions occur.
The aim of the current paper was to determine the influence of the feed rate on the quality of surfaces processed by AWJ at high pressure. The parameters that quantified the quality of the processed surface were those defined in the ISO/WD/TC 44 N 1770 standard: width of the processed surface at the jet inlet (Li), width of the processed surface at the jet outlet (Lo), deviation from perpendicularity (u), inclination angle (α) and roughness (Ra).
Biosorbtive removal of the antibacterial drug, ethacridine lactate (EL), from aqueous solutions was investigated using as biosorbent Saccharomyces pastorianus residual biomass immobilized in calcium alginate. The aim of this work was to optimize the biosorption process and to evaluate the biosorption capacity in the batch system. Response surface methodology, based on a Box–Behnken design, was used to optimize the EL biosorption parameters. Two response functions (removal efficiency and biosorption capacity) were maximized dependent on three factors: initial concentration of EL solution, contact time, and agitation speed. The highest values for the studied functions (89.49%, 26.04 mg/g) were obtained in the following operational conditions: EL initial concentration: 59.73 mg/L; contact time: 94.26 min; agitation speed: 297.57 rpm. A number of nonlinear kinetic models, including pseudo-first-order, pseudo-second-order, Elovich, and Avrami, were utilized to validate the biosorption kinetic behavior of EL in the optimized conditions. The kinetic data fitted the pseudo-first-order and Avrami models. The experimental results demonstrated that the optimized parameters (especially the agitation speed) significantly affect biosorption and should be considered important in such studies.
The workplace accidents are considered major sources of risk in the term of occupational safety. In these sense the employers take in consideration the workplaces risks plans. Risk workplace assessments allows employers to ensure preventive plans to limit or eliminate the risk factors by: selection of adequate working conditions, limited risk exposure, implementation of the proper individual safety equipment's, periodical medical inspection, ergonomic workplace design. The current paper presents the results of the occupational risk assessment at the level of the Faculty of Engineering within the "Vasile Alecsandri" University in Bacau. The assessment was conducted by applying the method developed by the National Institute of Research and Development for on Labour Protection, Bucharest. Risk assessment enables the identification of risk factors from analysed system, for the each risk factor, by components: production equipment's, workplace conditions, type of work, work performer as well the risk reduction and prevention. The overall risk level calculated varies between 2.69 and 3.10. The distribution of risk factors by generating sources indicated, for all jobs, as principal risk factor the work resources. The second risk factor was specific for the performer and workplace and the last was work task risks factors.
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