Volume 16 (2022): Edizione 1 (April 2022)

This paper presents a model that combines ontology, UML modeling, and a relational model. The ontology model (and the Ontology Web Language - OWL), UML, and relational model are first introduced in the article. After a review of the literature, the comparison and conversion of the systems are presented. The created model is then presented and a real ontology is modeled using the presented model.

The paper deals with theoretical bases of the implementation in mining equipment design of up-to-date methods using modelling and simulation, supported by examples of personal research. This has become necessary due to the structural complexity of this equipment, and the variety and aggressiveness of their operating environment. The presented examples refer to different kinds of the equipment used in the mechanical extraction of mineral raw materials, from overall system to working part or tool.

Mining machinery and equipment have changed little in recent decades, from the point of view of the principle of operation, construction and structure. But in terms of dimensions, performance and stresses they have made a lot of progress, experiencing unprecedented sophistication and complexity. In order to fulfil the new requirements imposed by the increasing productivity and efficiency demands, as well as the economic, environmental and safety constraints, their design and development must comply with the general advance of overall technology. Therefore, recently, modern analytical methods have also been included in the design and development of mining machines. Among other issues, the present paper examines the theoretical and conceptual aspects related to the mining machinery’ design requirements involving mechatronics.

The Harghita County Council has decided to carry out a self-assessment to evaluate the adequacy of its processes in the framework of a complex organizational development project using the CAF (Common Assessment Framework). The outcome of the performed self-assessment showed the capabilities and results of the operation, as well as the tasks of ensuring short- and medium-term development. This article aims to point out the needs and possibilities for improving administrative processes by presenting the experiences of the project. An important experience of the project is to prove the necessity of taking into account the specific features in addition to prove the general applicability of the model.

With the advancement of technology and the drastic increase in the number of noise sources, environmental noise emission is increasing year by year. In the case of urban dwellers, noise from road traffic accounts for the largest share of noise pollution, with a number of negative health effects. The aim of our research is to monitor the road noise emission of the city of Debrecen in detail, using hourly traffic data. After data processing, various situations were modeled according to the MSZ 15036:2002 standard with the help of the IMMI noise mapping program. Overall, it can be said that the studies we have carried out support the high level and increasing trend of noise exposure.

The most simple and robust construction of the monolithic gear hobs present a common helical rake face for a given line of teeth, whose generatrix is a straight-line segment perpendicular to the hob’s axis while its directory is a helix, perpendicular to the pitch helix. As a consequence, constructive rake angles are zero on all edges. Total curvatures of such a surface are negative. Thus, it can be grinded only using the conical surface of a platter type grinding wheel, or a grinding bit. Despite this, some industry practices, possibly for reasons of simplicity and cost lowering, involve the plain grinding surface, supposed to a helical motion. This paper deals with the CAD-simulation of the grinding process using the plain wheel surface, and it shows the differences between the theoretical and rake face and the real obtained helical surface.

Due to urbanization and the significantly increasing number of vehicles, urban roads are becoming more congested day by day, with the result that the rear-end collision has become the third most common type of collision. By developing and integrating active and passive safety systems, car manufacturers are working to prevent accidents and reduce the consequences of an accident. The present study examines a braking procedure and its applicability based on the integration of a passive and active safety system and provides development guidelines for the reduction of personal injuries and property damage in the event of a rear-end accident.

Throughout Transylvania, the ruins or remains of many engineering structures and buildings can be observed, and this allows us to draw a lot of interesting conclusions. This research seeks to shed some light on the design process of older bridges in Transylvania through a case study. Hydraulic calculations based on field measurements show the hydraulic requirements used in the original design of the bridge. The obtained data was compared to the current requirements of the Romanian design standards.

In this paper, we simulate the operation of a spading machine on three soil types; easy to work, medium to work and heavy, using a previously validated SimuLink model of an MSS-1.40M spading machine. We determine the forces during spading. We explore the physical and mechanical properties of the soil that play a role in the spading process. By simulation of the spading process with the MSS-1.40M spading machine, we determine the torque on the drive shaft and the required mechanical work on the three soil types.

Tools are devices for machining materials which must have different properties depending on their intended application. These properties are determined by the chemical composition and microstructure of the tool steel. The desired steel microstructure can be achieved with suitable heat treatment technology. During this heat treatment, the microstructure of the tool steel may develop various lattice structural transformations which in turn can cause internal stresses, cracks and distortions. One possible reason for these undesirable results may be the retained austenite. These effects are most pronounced in tool steels. In this study, the possibilities for reducing the amount of residual austenite during the heat treatment of tool steel is investigated.

In this paper chromatic discrimination thresholds of normal colour-observers are analysed. Measurements were obtained with the Cambridge Colour Test, in different reference points. The results show differences in terms of the reference chromaticities. Reference points within the gamut of a CRT display were found where thresholds of normal colour observers measured towards the confusion points exceeded the normative upper threshold limit of normal colour observers. The discrimination thresholds estimated towards the confusion lines based on Trivector measurements exceeded the thresholds estimated by the Ellipse tests. Our results indicate that in case of determination of discrimination ellipses, measurements towards the confusion points are recommended.