Scientific Bulletin Series C, Volume XXXVI (2022)

The Influence of the Static Loading of the Bearing Subjected to Shock on the Damping Capacity of the Lubricant Film for a Radial Bearing with L/D=0.5 as a Function of Spindle Speed

Ioan Marius Alexandrescu, Radu Iacob Cotetiu, Adriana Gabriela Cotetiu, Dinu Daraba

Abstract: This paper presents experimental research on influence of the static load of the bearing subjected to the shock on the damping capacity of the lubricant film depending on the spindle speed. We focus on determination of the acceleration taken during the shock by the bearing-lubricant film-spindle system under different static and dynamic load conditions.

Keywords: acceleration of the bearing, damping capacity, radial sliding bearing

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The Factorial Experiment used in the Analysis of the Quality of Noxes Emitted by Automobiles

Mihai Banica, Alina Bianca Pop, Aurel Mihail Titu

Abstract: Although we are in a continuous development thanks to technology, we are too little aware of the impact technology has on the environment. Thanks to technology, new constituents appear that have a harmful effect on air pollution. One of the main sources of environmental pollution is transport. To analyse the quality of exhaust fumes from cars equipped with spark ignition engines, in this case study a factorial experiment was carried out with six influencing factors on an objective function. The factorial experiment allows us to create three-dimensional graphs, graphs that allow a fine interpretation of the input data and pertinent conclusions that are obtained on the researched object. As a result of the experimental research, the inclusion of gas emissions in the normal parameters according to the norms of the Euro classes was followed. The collected data were processed with the help of active type factorial experimentation research, they were entered into the statistical software, resulting in graphs with the necessary information that can be used in the optimization of the objective functions. From the collected data, it results that regardless of the parameters of the influencing factors, the values of the objective functions are within the parameters according to the Euro norms.

Keywords: automobiles, factorial experiment, noxes, statistics

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Study on the Equation of the Theoretical and Experimental Attachment Current Line for a Bistable Fluidic Element with Jets of Different Physical Nature

Adriana Gabriela Cotetiu, Radu Iacob Cotetiu, Ioan Marius Alexandrescu

Abstract: This paper presents the possibility of determination of the experimental attachment flow line for the wall – attachment digital device and its equation. The function of this element is based on the controlled attachment of the main jet at a curved wall through the Coanda Effect. For this purpose, it was used the method of image analysis and then, taking over points was processed with soft program aid. The experimental obtained flow line was compared with theoretical curve. The bistable element which was examined is a special device with an incompressible fluid as supply jet and compressible fluid as command jet.

Keywords: attachment flow line, bistable element, Coanda Effect

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A Smart Way of Planning the Enterprise Resources

Florina Pop, Dinu Darabă

Abstract: The theme of this study is how to do a smart planning of the enterprise resources that combine the most important key operations for each resource used in companies (Human resources, financial resources, Production resources, Logistics resources). The study case is for an enterprise that has as principal activity the product customization, but this system of planning can be applied in other areas of activity also. The system proposed aims to present the most important criteria’s of planning the resources in each area and how to highlight and interpretate the results obtained. As advantages of this way of planning together the resources of an enterprise we can count a good organization of the production, human resources, financial resources and stocks. The main impact after a good organization of the enterprise resources is to limit the financial and material losses, but also to obtain a good profit after selling the service or the products. The objectives of the study are plan the production resources using the specific formulas of calculating the capacity needed of each operation for production, plan the human resources needed and the costs with them, calculate the stock needed for production, calculate de cost of production and delivery, highlight the results in graphics. In order to obtain all these results we used Saga Software and Qlik Sense platform. The Saga Software was used in order to enter all the information about materials consume, human resources needed and the costs with them, obtain all the official documents needed for receive the materials, do the paying, collect the payments, administrate the stocks of materials needed, depreciation of technological equipment. Qlik Sense is used to do the Gantt chart for human resource planning, divide the production capacity needed and highlight the results obtained into graphics.

Keywords: balance of capacity, business intelligence, payroll, profit, smart resource planning, stock management

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Investigating the Importance of Base Plate Preheating in the Selective Laser Melting Process

Jiri Hajnys, Marek Paga, Jiri Kratochvil

Abstract: The article deals with the impact of preheating the base plate on the generated residual stress in additive metal 3D printing technology, namely the Selective Laser Melting (SLM) method. Fifty pieces of bridge-shaped samples were experimentally printed (aluminum and stainless steel). Twenty samples were made of aluminum alloy AlSi10Mg, ten without preheating the base plate and the other ten with preheating the base plate to 170 °C. In each set, the bridges were further divided into groups. The given groups differ in the direction of the scanning vector, it also affects the residual stress. The residual stress is evaluated by measuring the deflection of the bridges. Each measurement was repeated four times and the resulting values were compared. Using the same methodology, 316L stainless steel samples were also printed and verified.

Keywords: SLM, Heat Treatment, Base Plate, 3D Print

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Review and Comparison of Flow Measurement Techniques

Alexander Baron von Hohenhau

Abstract: This article compares common methods of measuring pressure and velocity in liquid and gaseous flows. To this end, a graphical overview of the different types of pressures is presented. Furthermore, it is shown how multi-hole pressure probes can be used to not only measure pressure, but also to compute the component of velocity. This pressurebased measurement technique is compared to optical-based Laser Doppler Velocimetry and Particle Image Velocimetry. While the latter two methods are more recent developments and do not disturb the flow, it is shown that multi-hole probes are still a viable option for modern research facilities.

Keywords: flow measurement, pitot tubes, multi-hole probe, laser doppler velocimetry, particle image velocimetry

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Research and Optimization of 3D Printing Process Parameters for Supportless 3D Printing with Powder Bed Fusion Selective Laser Melting

Pagac Marek, Jiri Hajnys, Jan Krejčí, Josef Hlavsa, Jiri Kratochvil

Abstract: The Laser Powder Bed Fusion Selective Laser Melting technology has a wide range of applications. This technology requires 3D printing of the support material, which has advantages and disadvantages. Considering the current trends that are led by the elimination of 3D printing of support material, this manuscript deals with the optimization of process parameters with the elimination of 3D printing of support material. In the introduction of the manuscript, research is described that summarizes the findings of this issue in foreign countries. In the experimental part, 3D printing of samples with different printing parameters was carried out and their effect on the quality of production was observed. The results of the experiment are a source of information for follow-up experiments, which will be the measurement and evaluation of mechanical properties. The results of the experiment have application potential.

Keywords: Powder Bed Fusion, SLM, Selective Laser Melting, 3D Print

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Contributions Regarding the Study of Noxes in Automobiles Equipped with Spark Ignition Engines

Aurel Mihail Titu, Alina Bianca Pop, Mihai Banica

Abstract: Nowadays, internal combustion engines, with spark ignition, are still used in transport, and they are the focus of major car manufacturing companies that are looking for solutions to reduce polluting exhaust emissions and noise. The big car manufacturing companies present us with the latest technologies for obtaining performance engines and the methods of eliminating the noxes emitted by them. The spark ignition engine is considered the most polluting due to its spread in several fields of activity. For a correct analysis of internal combustion engines with spark ignition on the environment is the study of the emission of particles that represent the totality of the matter collected on a Teflon filter when the burnt gases pass through. The measurements conducted on vehicles of different brands and years of manufacture revealed how important the technical condition and the emissions emitted by them are. The main purpose of this scientific paper is to show how important the quality of the noxes resulting from the exhaust gases produced by internal combustion and spark ignition automobile engines is on the environment and implicitly on the population.

Keywords: automobiles, noxes, spark ignition engines, the active type experiment

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