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The main topic of this paper is to analyse the approach to fault – finding, tests and maintenance regarding on what shall and shall not be done in an installation in hazardous area from the point of view of the explosion – protection safety. For a fault it is usual to be investigated by following a logical routine. This is one possible ways of proceeding developed from good engineering practice and experience in general terms. The test equipment for use in hazardous area will be either certified or uncertified. The maintenance is regarding in this paper from the point of view of SR EN 60079 – 17 starting from general requirements.

The flameproof enclosure type of protection is still one of the safest because it is based on a very simple and, therefore, unlikely fallible technology. If an explosive atmosphere penetrates an enclosure producing a trigger, the explosion occurs, but it remains confined within the enclosure. EN 60079-1 standard, states that flanged flame paths are allowed in the presence of gases and vapours of Group IIB, but cannot be used with gases and vapours of Group IIC. Also, flame transmission tests for Group IIB equipment are carried out at atmospheric pressure, whereas for Group IIC equipment they are conducted (depending on the testing method applied) at a higher initial pressure. The purpose of the paper is to perform a thorough study upon the differences between testing of flameproof electric motors of Group IIC, compared to electric motors of Group IIB gases and vapours, in terms of testing conditions required by the standard and how the explosion group influences the maximum explosion pressures and explosion pressure development, when tested in explosive mixtures of gases and vapours. The purpose of this paper is to assist manufacturers in designing flameproof electric motors that satisfy the requirements of the specific standard for either Group IIB or Group IIC applications in order to smooth the path for certification.

According to Directive 2010/75 / EU and Law 278/2013 on industrial emissions, operators of large combustion plants (IMA) must carry out continuous self-monitoring of pollutant emissions and are required to perform parallel measurements with accredited laboratories, to certify results. Thus, INCD INSEMEX Petroșani, through the Testing Laboratories Group, accredited by RENAR, offers these type services to various economic agents. The curent paper presents measurements performed at two IMA exhaust chimneys, in two different stages, to quantify pollutants released into the atmosphere and to establish the impact they generate on health of population in the area of the study. Analysis of results showed that the maximum allowed value for the SO2 was exceeded, so that, at the end of this paper, some recommendations were reviewed, according to BAT (Best Available Techniques), to support the economic agent and inhabitants of the area in haveing a cleaner environment.

The most affected field of the society by the two-year COVID-19 pandemic was undoubtedly the medical one. An analysis of the most important changes that have taken place in this field, from the perspective of human resources in the medical sector, is the main objective of the research. A first step in this complex analysis, however, is to identify the situation of human resources in the medical sector from the perspective of its satisfaction in the pre-pandemic period. The present paper aims to highlight the situation existing in the Romanian medical system prior to the pandemic from the perspective of employee satisfaction, through a research conducted in a medium-sized hospital in Romania. The research method used was the survey, with 144 respondents, represented by the employees of the hospital, questionnaire applied in 2018 and 2019 years. One of the conclusions of this paper is that improving employee satisfaction from the perspective of human resources management in the organization studied, increase the quality of medical services offered to the patients, and therefore increase patient satisfaction.

This paper offers a review of fundamentals in decision analysis and the construction of evidence-based probabilities for use in decision-making. The term quantitative risk analysis generally connotes reliance on probability and statistics. However, select quantitative risk-based decision-making methodologies, such as game theory, do not require knowledge of probabilities. Maximizing the minimum (maximin) gain, minimizing the maximum (minimax) loss, or maximizing the maximum (maximax) gain are but a few examples of decision-making criteria for handling risk and uncertainty without adhering to probabilities. Quantitative risk assessment builds on the existence of probabilities that describe the likelihood of outcomes, such as consequences. In general, probabilities are derived on the basis of historical records, statistical analysis, and/or systemic observations and experimentation. We commonly refer to probabilities that are derived from this process as "objective probabilities". Often, however, situations arise where the database is so sparse and experimentation is so impractical that "objective probabilities" must be supplemented with "subjective probabilities" or probabilities that are based on expert evidence, often referred to as "expert judgment". This paper focus on generating probabilities on the basis of expert evidence, using by the decision rules under uncertainty.

The paper presents an inventory of the activities of the elderly before and after retirement. The objectives of this paper are: to identify and analyse the activities of the elderly before retirement; to identify and analyse the activities of the elderly after retirement; to analyse the dynamics of the elderly’s roles; to build the intervention plans in relation to the elderly’s activities in correlation with the roles played by them. The interview is the method used in data collection and the results are obtained from the qualitative analysis of the data: inventory of answers, their classification into categories, coding of answers and their interpretation. The schedule of activities and the typology of activities have changed radically after retirement and the satisfaction of the elderly in relation to these activities varies depending on the health problems, depending on the financial difficulties and the relationships that the elderly have with the family. Most of the elderly people interviewed say that they try to stay active and satisfy their desires even if it is more difficult for them due to their health condition. They focus on helping and supporting the family, and they feel great satisfaction when it comes to helping them.

In this paper, we first bone up on the literature as regards the relationship between universities and the business environment and its role on the development of entrepreneurship as an engine of economic growth. We continued the paper by presenting this relationship in the context of introducing projects related to entrepreneurship within the University of Petroșani. In the methodology part, on the one side, the university - business entity partnerships are statistically analyzed and on the other side, the results of a enquiry that was applied to entrepreneurs during 2019-2021 within the POCU project ”EU - ENTREPRENEUR - increase of students participation from vulnerable categories to undergraduate study programs through entrepreneurial innovation ”POCU Contract /379/6/21. The paper brings to interesting conclusions about the relationship between universities and entrepreneurs and how it can intensify the efficiency of this collaboration from the perspective of increasing the entrepreneurial skills of students.

Workplace microclimate is determined by temperature and humidity of air, air currents and caloric radiation of work environments. All microclimate factors act combined and simultaneously on the human body. Thermal comfort plays a decisive role in mental and physical abilities of workers, and decisively influences workplace performance of employees. In order to ensure the highest possible yield for workers, employers mustregularly evaluate microclimate parameters by measurements. The paper presents a case study on the thermal environment of several metallurgical complexes in Romania, by calculating the PMV and PPD indices at various workplaces that are found in all studied units. After correlating the PMV and PPD indices for each workplace in particular, in all studied units, results were used to create a regression analysis that is expressed by a regression graph, in order to present as concise and objective as possible differences between the studied workplaces. Importance of the paper is outlined by the need to develop research in the field of Health and Safety at Work, in order to objectively assess working conditions in Romania and to develop new methods to ensure a proper work climate in order to maintain or increase the level of workers’ productivity.

The quench and partition process was studied in a high aluminium (Al) medium carbon (C) steel by varying the quench temperature which is one of the process parameters The first part of the paper deals with modelling athermal martensite transformation using an empirical approach. This model is an improvement on Koiestein and Marburger's model, and it better represents the martensitic transformation. The second part of the paper deals with microstructure evolution in high Al steel when subjected to the quench and partition process. The maximum retained austenite (RA) obtained was 13% at a quenching temperature of 260°C. The addition of Al promoted the formation of bainite during the partition stage.

This paper proposes a novel approach of Gaussian process observation set compression based on a squared difference measure. It is used to discard observations to speed up Gaussian process prediction while retaining the information encoded in the full set of observations. Furthermore, this paper compares the regression performance of a compressed Gaussian process to its uncompressed version and to a randomly downsampled Gaussian process for a standard two-dimensional test function. The empirical results of this paper show that this is an effective algorithm for Gaussian process compression, speeding up prediction while maintaining predictive accuracy with regards to the predicted means.

The paper describes the development of a non-invasive flowmeter for lower flow rates and its first tests. This gauge is physically based on the interaction of fluid flow with an ultrasonic signal that passes through the fluid from the transmitter to the receiver. Ultrasonic flowmeters are currently relatively commonly used gauges, whose advantages such as non-invasiveness (i.e. zero pressure losses) and the ability to seamlessly measure the flow rates of any (for example opaque) liquids, without contact with the liquid, are widely known. However, there are still parts of the ultrasonic flowmeter measurement chain that are undergoing research and development. It can be signal processing itself (mainly), its design solution, measurement for different flow cases (measurement in a flow field with a uniform velocity profile, in a flow field with an axisymmetric velocity profile, in a flow field with a general velocity profile), validation of the applied signal processing approaches, evaluation of uncertainties. The flowmeter itself, which development is described in the paper, will be used for trouble-free measurement in air engineering, but also serves as a training device for building a more complex ultrasonic gauge. Therefore, this flowmeter contains more signal transmitters and receivers than it is usual and all transmitter-receiver combinations are captured during the measurement. This gauge is called ultrasonic tomograph and its principle is also outlined in the paper. Here, so far, without a reconstructed vector field.

The use of battery storage systems (BSS) is an increasingly common topic in the context of the operation of various types of renewable energy sources (RES). One of the applications may be to solve the problem of energy-free operation of small hydropower plants, where quite specific requirements are placed on the design of the BSS. In the context of optimal BSS design for a given application, this paper discusses the computer analysis capabilities that are essential in the design and performance verification phase of a BSS. The paper presents the possibilities of simulation methods in the field of electrical analysis of cell current load during charging and discharging processes, thermal analysis related to the selection of a suitable cooling system with respect to the operating mode of the battery system.

The paper deals with the principles of hydraulic design of runners of axial turbines or pumps. The procedures of classical methods of hydraulic design of primary runner geometry and the possibilities of subsequent optimization of this geometry by CFD simulation are presented. In the paper, the advantages of the procedure of hydraulic design of the primary runner geometry of a tubular Kaplan turbine with the application of the classical methods and the subsequent CFD simulation are shown on a specific example. The purpose of the CFD simulation is to verify the achievement of the required parameters of the designed runner geometry and its possible fine-tuning and optimization.

This paper presents an approach to the use of the PIV method in the diagnosis of sprays generated by an effervescent atomiser. Due to the different density of the liquid phase depending on the distance from the nozzle, problems arise with the correct exposure of images for PIV analysis. The aim of the authors of this paper is to outline the possibility of solving this problem by composing a velocity field from partial measurements. To meet the objectives of the paper, in-house PIV equipment (hardware and software) was used rather than a commercial setup. This allowed for easier handling of the measured data and more sophisticated post-processing than offered by commercial products. It is clear from the results presented that, despite the fundamental differences in the optical properties of the spray particles, it is possible to obtain a velocity field from the discharge zone to the spray region with fine droplets. Moreover, it is possible to combine velocity measurements in the spray cone with measurements in the surrounding environment. Research background: Spray is an environment with an abundance of tracers for PIV analysis (droplets), but their density, size and shape vary dramatically with distance from the nozzle. The use of PIV can therefore be challenging due to the demands of this method for correct image exposure. Purpose of the article: Introduction of the application of the PIV method for environments with variable density and size of tracer particles Methods: PIV, image processing. Findings & Value added: By taking an appropriate approach to acquiring the source PIV images, it is possible to obtain information about the velocities throughout the spray cone as well as in the surrounding environment. The application of the proposed method requires a sufficiently large source data set (images) and sophisticated postprocessing. However, as a result, it is possible to obtain an overall view of the velocity field in the spray cone starting from the area behind the nozzle to the fine droplet region.

Abstract. This paper is devoted to the development of a new probe to measure a drift from cooling towers. The probe was named DPIK (Drop Hunter Isokinetic) and its development consists of a design of the aerodynamic and microelectronic part of the probe, verification methods, design and testing, verification tests in laboratory conditions and measurements on a model of the cooling tower. The paper deals mainly with the verification tools, as these methods are very closely related to the aerodynamic part of the probe design. Two options were chosen for verifying the probe principle. The first of these was the Interferometric Particle Imaging (IPI) method, the second was another optical method using similar experimental equipment Particle Image Velocimetry (PIV).

In this paper, the surface cracks of deep-sea ring-shell structures are studied. In this paper, the geometric and physical parameters of 1000m underwater titanium alloy ring shell structure were analyzed. Firstly, the mathematical model of its relevant contour curve was obtained by combining with the parameter equation. Based on the mathematical model, the finite element model was established and the force analysis under static equilibrium condition was carried out. Secondly, the stress maximum point was solved by finite element analysis, and the initial crack was added at the stress maximum point. The stress intensity factor method was used to analyze the stress intensity factor and crack propagation. Finally, according to the physical parameter load, stress ratio, morphology coefficient and different Angle analysis, the influence factors that interfere with crack growth and the dynamic trend of crack morphology were evaluated. Aiming at the study of dynamic performance of cracked ring-shell structure, the crack characteristic curves under different complex working conditions were analyzed to deepen the research in related fields and provide some scientific reference for the study of related ring-shell structure.

Periodic Surface Structures (PSS) fabricated via Additive Manufacturing (AM) have recently emerged as being appropriate candidates for high-value engineered structures. Among the many PSS designs, gyroid structures have demonstrated merits in mechanical properties and permeability compared to traditional lattice structures. Periodic surface structures are mathematically formulated by geometric factors: surface thickness, sample size, number of surface periods, or unit cells. These elements produce a continuous sur-face with specific topology. Numerical simulations of the effect of modulating these factors on overall thermal and mechanical properties require substantial computational resources and give a quite good qualitative assessment. Cubic P-surface (“Primitive”), D-surface (“Diamond”), and gyroid surface structures of various designs were simulated under load and heat transport using a numerical approach. The influence of geometric factors on thermal and mechanical behavior was determined qualitatively. The results show the impact of the number of cells and surface thickness on both thermal and strength modulus. The paper focuses on thermal and mechanical analysis of periodic surface structures. The study is conducted by solving the stress and heat equations using the Finite Element Method (FEM) and is achieved with the use of our authorial software. Our software module generates periodic surface structures and simulates stress and temperature distribution in it. The stress model is defined by dependence between stress and strain, it got from an experiment, and the correlation of strain and displacement got from geometric conditions. In the paper, we present calculations for three-dimensional systems in which we analyze the stress and temperature distribution depending on the geometric factors. The results presented allow estimation of the behavior of periodic surface structures under loads. It intends to evaluate the possibility of crack occurrence in complex structures based on the performed numerical simulations in future work.

The aim of this paper is to present a method of computer formulation and solution of equations of kinematics of spatial mechanical systems. The method of the vector closed loop is generally known way how to built the constraint equations. This method is recommended for planar kinematics. This paper shows the way how to take advantage of the vector cross product, vector magnitude and scalar product of two vectors for getting the constraint equations for spatial mechanism.

Many infrastructure domains required material research as an initial phase of project development life cycle. One such futuristic domain is bridge engineering, where there is a critical need of study of environmental impact and material strength. This paper focuses on the premature deterioration of concrete infrastructures exposed to sodium chloride (NaCl) salts in the presence of thermal cycling. NaCl salts can cause damage and rapid deterioration of concrete due to physical and chemical aspects, including salt scaling, corrosion of rebars, ice and salt crystallizations and/or deleterious chemical reactions. This paper discusses how NaCl solutions can cause damage in concrete in the presence of thermal cycling and how such damage can be mitigated. This paper at-tempts to provide an advanced thermo-chemo-physical understanding of NaCl salt damage in concrete. This paper also discusses specific structural and chemical alterations during thermal cycling that are caused by NaCl to develop damage to concrete. Results indicates that the heat-cool cycling induces the formation of mirabilite (Na2SO4.10H2O) in concrete exposed to high concentrations of NaCl solution. The mirabilite formation is found to be due to the release of sulfate ions from the concrete matrix.

This paper presents the results of a study based on practical experiences and cases with regard to the need for maintenance of installed CP systems over the past 35 years in the Netherlands. CP is a proven technique for long-term protection of steel in concrete against corrosion. Corrosion can lead to significant damage to reinforced concrete and ultimately result in a reduction in the load-bearing capacity of the structure. Correct application of CP can prevent this. Over 35 years, CP has been successfully applied in the Netherlands to all kinds of concrete structures in the industry, residential buildings, infrastructure and even monuments. CP normally distinguishes itself from other repair techniques by its long service life and durability. With careful application and professional monitoring, a service life of 15-30 years or even longer can be achieved. Nevertheless, there have been applications in which the CP system had to be maintained in the shorter or longer term or even completely replaced. Although every application requires maintenance, this maintenance sometimes came completely unexpectedly or much too soon. This paper gives an overview of a number of such projects and identifies the causes and consequences (in scope, costs and effects) of the relevant maintenance measures.

The paper discusses the possibilities and methodology of utilizing software, designed to be used with a double ball bar device to analyze CNC machine tool positioning performance, to analyze measurements measured by a different method. The Renishaw Ballbar system is a special tool designed to allow rapid and highly effective checks of positioning performance of any numerically controlled cartesian structure, such as a CNC machine tool, and at the same time allows monitoring its condition and to some extent predict its future development. The system uses sophisticated algorithms to decompose the overall measured inaccuracy of examined machine to values of individual errors and offers possible actions to remove such errors. The ability to push different measurements of circularity, such as measurement of circularity of machined surface on a coordinate measuring machine, would allow checking the presence of various errors without the necessity to measure with a double ball bar device. Therefore, the paper presents the custom software, that shows such possibilities, which was developed at the Department of Automation and Production Systems, Faculty of Mechanical Engineering, University of Zilina.

The application of impressed current cathodic protection (CP) is a well-established technology for the corrosion protection of reinforced concrete structures situated in marine environments. While the protective benefits of cathodic protection are well known, the lasting effects following the discontinuation of CP current are not entirely understood. This paper presents research findings on the residual protective effect which is known to occur following long durations of impressed current cathodic protection. The residual effect was replicated in university laboratories using reinforced concrete test blocks and accelerated CP testing methods. The experimental results depicted a clear improvement in the electrochemical state of the reinforcing steel with a shift of 150 to 300 mV to more positive values following CP application. The research also involved analysis of monitoring data from six in-service cathodic protection systems which were operating in Australia for nearly two decades. The behaviour of the steel potential readings was analysed and the results of the combined research confirmed that the protection provided by cathodic protection systems does not actually cease when the CP current is switched off. Rather, the embedded steel undergoes a significant and sustained shift to more positive values and this phenomenon is documented and discussed in this paper.

This paper presents a numerical finite element analysis of pipelines with small misalignment under internal pressure using a developed fast pipeline modelling system ABAP using Python development environment of ABAQUS. The effect of small misalignment is shown to affect at most 10% of stress levels. Extensive parametric analyses have been conducted on the pipe length, pipe thickness. Pipe length has trival effect on non-uniform stress distribution when length/diameter ratio is greater than 1. For thinner pipe, misalignment amplifies the circumferential non-uniformity more significantly than thicker pipe. This paper serves to enhance the understanding of pipes with small installation misalignment defects under pure internal pressure.

Lubricating oil is known as "the blood to maintain the normal operation of machinery", and additives are an indispensable and important part of lubricating oil. In this paper, the Polymer-based Composite Nano-additive (PCNA) suitable for armored vehicle engine lubricating oil was developed, the physical and chemical properties of lubricating oil containing additives were carried out. The results showed that adding an appropriate amount (3 vol.%) of additives could improve the low-temperature fluidity of lubricating oil and improve the kinematic viscosity of lubricating oil without affecting the viscositytemperature characteristics of lubricating oil. The four-ball testing machine, high temperature end face testing machine and engine bench are used to measure the anti-friction lubrication effect and anti-wear ability improvement effect of the additive on lubricating oil. The experimental results show that the additive can effectively improve the antifriction, lubrication and anti-wear performance of lubricating oil. In addition, the addition of the additive can effectively improve the running state of the engine, and the engine noise is obviously reduced. Finally, the additives developed in this paper are compared with three common brand additives in the market by using the high temperature end face testing machine. The results show that the additive developed in this paper has certain advantages in improving the antifriction and lubrication effect of lubricating oil.

With the continuous development of the Internet financial industry, its impact on people's daily life is growing. Under the influence of the information technology and the financial innovation, the volatility of the financial market has been significantly enhanced, and the financial risk has become increasingly serious. The COVID-19 in 2020 still has a profound impact on the global financial market. The reasonable measurement of the financial risks is the most important step in the financial risk management. Based on the sample analysis of the Standard & Poor's 500 Index from January 3, 2013 to June 30, 2020, this paper measures the risks by analyzing and calculating the value at risk (VaR) of the sample data by different methods. This paper mainly establishes the ARMA model, the GARCH model based on bayese statistics, and the POT model based on the extreme value theory, and compares and analyzes the VaR values obtained by the three models. Finally, the effectiveness of VaR is tested by VaR backtracking test, and the advantages and disadvantages of the methods are compared and evaluated.

Reduction of the force interaction between vehicle and track is strongly desirable for many reasons. Because conventional methods of reduction of wheel-rail contact forces, based on tuning of vehicle suspension parameters or utilising various mechanisms acting between wheelsets, bogie-frames and car-body, reach their limits, active controlled systems are becoming a promising solution of the problem. The paper is created within the project which aim is to design a system of active wheelset steering for an electric four-axle locomotive. The project consists of three main stages: multibody simulations, scaled roller rig experiments and field tests. One of the important elements of wheelset steering system is the estimation of the actual track curvature. The paper focuses on the track curvature calculation based on the rotation of the bogies towards the bogie-frame. The method of track curvature calculation is proposed and assessed across varying track radiuses, vehicle speeds and friction conditions.

In this paper existing active and passive radial guiding systems of railway vehicle wheelsets are presented. The new system described in this paper is based on non-direct measuring lateral forces in bogie elements. As a part of project development there where numerical calculations and experiments on a test stand carried out. As a main issue, there where investigated stress signals from extensometers mounted on guiding elements of wheelsets. In conclusions, there is made a comparison between values obtained from numerical and experimental tests.

In order to meet the targets set out in the Paris climate agreement of 2015, the energy sector needs to be restructured. In Germany for example the goal is to move out of both nuclear and coal-fired power. In order to fulfil more demanding energy requests alternative sources of energy must be found and made available. One component is the usage of Waste Heat Recovery. This paper deals with the evaluation simulation of an Elektra turbine, which concept is a velocity compounded radial re-entry single wheel turbine. Based on the first turbine design, multiple simulations were carried out in order to maximize the efficiency. With these simulations, optimization opportunities are described and identified. The paper concludes with a comparison of the results achieved by numerical simulation and on the experimental test bench. The main focus for this paper is to analyze the actual flow phenomena to identify possibilities for further improvements. All simulations were calculated with the commercial software FINETM/TURBO 15.1.

In many industrial applications where compressed air is used it is necessary to increase the quality of the air by decreasing its humidity. This is done by either a condensation or adsorption dryer in the compressor circuit. In this article, the focus is on an industrial adsorption air dryer. The dryer is briefly described together with its function and a selected range of adsorbents suitable for air drying. The paper further deals with the development of a mathematical model of air humidity adsorption which is based on the Pseudo Gas-side Controlled (PGC) model. This paper contains a detailed description of the model and describes its implementation in MATLAB. Finally, the results of the simulations are discussed.

This paper describes the effects of guide vanes installed in curved conduits with the main emphasis on pressure loss reduction. In curved parts of conduits, eddy zones are created due to the flow separation resulting in an increased value of pressure drop. Installation of guide vanes can prevent the creation of large eddy zones. On the other hand, the cross-section of the conduit is decreased by placing the vanes, leading to the growth of the pressure drop. That is why the properties of guide vanes needed to be selected carefully. The goal of this paper is to describe the process of finding the optimal number of vanes in order to obtain the lowest value of pressure drop in the curved conduit. This is achieved by a parametric case study in Ansys DesignXplorer combined with CFD simulations in Ansys Fluent. The case study parameters are the number and thickness of vanes, dimensions of the conduit, and the inlet velocity. Our results are compared with recommendations on the optimal number of vanes from Idelchik [1].

For a long time, and especially today, the energy crisis has been a limiting factor for the growth and development of the world economy. On the other hand, improving the reliability and readiness of energy production systems is becoming a first class priority for research and development institutions around the world. Therefore, the process of production, transport, distribution and usage of energy is increasingly becoming a very important part of smart systems, whose basic framework is Industry 4.0. Thus, starting from the analogies between industrial manufacturing and mining (i.e. “ore production”), the concept of smart mining is developed. This model has three dimensions: (i) application of advanced digital technologies (Cloud Computing and Internet of Things) with automated Cyber-Physical Systems (CPS), Adaptive Manufacturing Processes (depending on working conditions) and Control of Manufacturing Processes (with optimal resource usage); (ii) Smart Maintenance of CPS (for machinery and equipment); and (iii) Smart Supply Chains (procurement of materials and spare parts / delivery of final products). Deeper analyses have shown that most of the Industry 4.0 elements could be applied with some modifications in mining (there are 45 in total, and analyses have shown that 32 of them can be successfully applied in smart mining) – which was the starting point for the ERP model presented in this paper. The developed ERP model has three main parts: a virtual part based on the Cloud Computing model (SaaS model) and usage of Internet of Things to connect different business processes (procurement, sales, management, finance, warehousing, downtime monitoring etc.), the manufacturing part (coal production in open-pit mine) and the technology process part (monitoring and maintenance of auxiliary machinery). This paper presents the developed and partially implemented ERP model for Industry 4.0 in smart mining at one surface coal mine in the Republic of Serbia.

The paper deals with geometrically-accurate crossed-axes gearing that features line contact between the tooth flanks of a gear, and of a mating pinion. The gearing of this design is commonly referred to « R – gearing ». R – gearing is the only possible kind of crossed-axes gearing, in which the tooth flanks of a gear, and of a mating pinion are in line contact with one another. Contact motion characteristics, and the key elements of dynamics of R – gearing are concisely outlined in the paper. The tooth profile sliding, and sliding in the lengthwise direction of the gear tooth, are covered at the beginning of the paper in the section titled Contact motion characteristics. The key elements of dynamics of R – gearing are discussed in the rest sections of the paper. Here, analytical solution to the problems under consideration is presented. The obtained results of the research are also valid for gear pairs that operate on intersected axes of rotation of a gear, and of a mating pinion. This becomes evident if one assumes the center-distance in the gear pair equal to zero. The discussed results of the research form a foundation for the further analysis of dynamics of real gear pairs that operate on crossing axes of rotation of a gear, and of a mating pinion.

This paper presents the work of 5 PhD students in elaboration of their doctoral thesis, especially for the first part of the thesis, namely the state of the art. The method used was The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA). Using the chart flow and the list of items of this method, a literature search was conducted in Science Direct Freedom Collection, Elsevier database, Web of Science - Core Collection, Springer Link Journals. In this paper are given 2 examples of systematic reviews that were obtained using PRISMA method.

According to the European Agency for Health and Safety at Work, changes in employment arrangements, new technologies and an increasing ageing population are key sources of emerging risks. New and emerging risks should be a major area of interest for every organisation, as a thorough risk prevention activity is key to high organisation efficiency and increased employee wellbeing. Musculoskeletal disorders (MSDs) are not a new risk category by themselves, but the changing characteristics of the work system generate new types of MSDs as a profession-related pathology (work-related MSDs). There is limited literature on this matter, hence the paper provides relevant insights and a new perspective on ergonomic risks and MSDs. Also, the paper presents a comparative analysis of ergonomic risks in the EU and Romania – based on secondary data – and identifies emerging risks in this category.

Sustainable public transport requires finding a balance between economic and social objectives, ensuring the need for mobility without damaging environmental and health factors. At the level of the Petroșani Basin, the aim is to ensure the mobility of passengers as quickly as possible from one city to another (from east to west - Petrila, Petroșani, Aninoasa, Vulcan, Lupeni, Uricani) or from one part of the city to another, as the case may be. The study of population fluctuations by hours, on working or non-working days, per season allows the realization of a public transport that ensures the movement of people as quickly and safely as possible. The purpose of this paper is to study the way in which public transport is carried out in the Petroșani Basin, the means of transport used and the possibilities to improve this activity. In the context of sustainable mobility, the paper includes necessary aspects (transport demand, influencing factors, infrastructure) in order to conclude on the future of public transport in the Petroșani Basin.

The evaluation of explosion-proof electrical equipment for certification is particularly important given the risk of explosion and must be minimized. This in order to ensure the safety of life, health of workers, to prevent damage to goods and the environment when they meet the essential security requirements at European level. Directive 2014/34 / EU states that equipment used in explosive atmospheres must be designed to operate without endangering the environment for which it is intended. This paper presents a comparison between the different types of cable glands for electrical apparatus by comparing some common characteristics that are important for maintaining the integrity of explosion protection. Consequently, this paper intends to be the precursor of a practical guide for the selection and implementation of different types of protection on the apparatus intended for use in areas with hazard of explosive atmospheres, both for designers and manufactures. This state of fact is negatively more emphatic because, lately, the groups of standards from this field in the world, Europe and Romania have a peculiar dynamic caused especially by the homogenisation and generalisation process opened and maintained by IEC.

The risk of explosion becomes significant when, in the industrial field, flammable substances such as gases, vapours, mists, dusts, lint and fibres may be present. If they are present in sufficient quantity, the risk of explosion is imminent. On the other hand, the measure of shutting down the technical equipment, in the context of the presence of explosive atmospheres, is not an acceptable measure in all situations. As examples are the parts of installations that have safety functions: ventilation installations, installations for monitoring the concentration of flammable substances and other safety parameters. Explosion protection of technical equipment shall be evaluated and tested in order to validate it. The testing process of the technical equipment for the purpose of explosion protection certification is situated at the confluence of several engineering fields: mechanical, electrical, chemical, etc. The first part of the paper deals with the risk of explosion and presents the explosion protection of the technical equipment. The systematized presentation of the technical equipment tests is performed in the second part of the paper. Among the conclusions it is mentioned that although the field of tests in explosion atmospheres is an interdisciplinary one, its coherence is ensured by the specific standards.

The implementation of calculation architectures, data acquisition and processing systems, VLSI type integrated circuits within driving systems shows and increased trend in the industry, due to the advantages of such circuits compared to microcontrollers and ASIC’s. In the first part of the paper is presented functional aspects of reconfigurable integrated circuits for monitoring, controlling and managing industrial processes. Compact RIO is a device developed by National Instruments and which is intended for monitoring and controlling industrial processes. This is also an “embedded” type system, which comprises a FPGA device, a processor with real-time operating system (RTOS) and various input-output modules which have to be attached by the user. Applications using such devices, usually also use an HMI (human machine interface) for creating a graphical interface with the user. The second part of the paper is allocated for establishing the requirements for using of such system in the explosive atmospheres. The practical achievement consists in the construction of a wirelessly PC-controlled robot and the analysis of measurements achieved, respectively data acquired from sensors and video recordings. Among conclusions is highlighted the opportunities brought by the use of the intrinsic safety and flame proof types of protection.

This study was designed to test the relationship between job satisfactions, communication style and conflict behaviour of employees in the public system, respectively in the territorial labour inspectorates. Research responds to practical needs highlighted by organizational psychology to identify the sources and dimensions that prevail and make the individual's perception of the organization lead to increased job satisfaction. However, the paper is not without methodological limits, represented by the use of self-report evaluation questionnaires that could involve poor identification and reporting, by the tendency of the facade that appears when the subject is not honest, offers answers that do not reflect its true feelings, principles and values, tends to avoid the appropriate responses to the state, only to leave a good impression, determine a positive judgment, placement in a situation of appreciation, or out of a desire to help the researcher in confirming the study hypothesis. The paper provides additional information for the scientific community, and can also be a starting point for other research by methodologically improving and bringing to the fore variables that can have a significant contribution to job satisfaction in civil servants, the subject being of maximum interest in the current context when a qualitative increase of services for employees and employers is desired.

Explosive atmospheres can be caused by gases, vapours, mists, dust, lint or fibres of flammable substance. If enough substance and air are mixed, the imminence of an explosion depends on probability and efficiency of the ignition source. Hazardous areas classified in sectors must be protected from ignition sources. Equipment and protective systems intended for use in potentially explosive atmospheres should be selected to meet the appropriate requirements for protective equipment and systems. The current paper aims to identify opportunities for standardization of pressurized equipment. The first part of the paper presents the risk of explosion associated with the presence of flammable substances and protection against explosions. The concept and opportunities of using pressurization are described in the second part of the paper. The third part refers to considerations regarding size and shape of pressurized equipment. A synthesis of pressurized equipment’s offer - dimensions, shape and functional role, is presented in the last part of the paper. Among the conclusions the existence of a gauge profile that depends on purpose, volume, operating position and assembly of the equipment, was mentioned.

This paper brings to the fore the need to study the causality of work accidents starting from the hypothesis that the causes must be identified immediately, respectively the dysfunctions of the work system, which contribute to their occurrence. So, in the causal chain of the work accident, the last link is the “meeting” between the victim and the material agent who injures her, and often the factors of the work system, which are potential causes of injury, are specific to the worker and represent an error inappropriate behaviour in terms of occupational safety, in the form of wrongdoing or omissions. In this regard, cognitive ergonomics is still an untapped area, although it can make significant contributions to improving work performance and creating safe and healthy working environments in industry. Cognitive functions are relevant when we talk about 4 essential skills of the worker, respectively: sensation and perception, attention, short and long term memory. The paper brings more information for the scientific community because the analysis highlights the link between the cognitive functions of workers and the errors generated by them in the dynamics of a work accident, and can also be a starting point for new research.

This paper aims to interpret and to use within a statistical analysis the concentration profiles of the main air pollutants – i.e., nitrogen oxides (NOx), sulfur dioxide (SO2), carbon monoxide (CO) and suspended particulate matter (PM10) – results recorded during the first half of 2021 by two air quality monitoring stations in Craiova, which is an important metropolitan area in Southern Romania. Another goal of the paper is finding the best numerical diffusion model to fit the recorded values for PM10, as this pollutant seems to be the major problem, because its daily average is often higher than the European Union threshold, meaning that imperative measures have to be taken for reducing particulate matter concentration in Craiova (like in other major Romanian metropolitan areas), in order for Romania to get the exoneration regarding air pollution from the European Union and, of course, for its citizens to improve the quality of their lives.

Only an objective knowledge of safety and health at work reality on the harbor platform and an active participation of all stakeholders (employers, unions, workers) can bring an improvement in this activity. The prevention of accidents at work by ensuring safe and healthy working conditions and maintaining the Occupational Safety and Health Management system are factors that continuously develop and improve safety performance by helping to actively manage risks. This paper aims to systematize the information available, both at European and national level so as to develop a strategy at the organizational level that can be included in a guide to optimal safety and health practices for harbor operations. The paper also proposes relevant practical aspects of safety and health at work in the activities carried out in the loading and unloading flow in / from the port of the ship, trying to support the knowledge and understanding of identification, assessment and prevention of specific risks.

With the development of EEG analysis technology, researchers have gradually explored the correlation between personality trait (such as Big Five personality) and EEG. However, there are still many challenges in model construction. In this paper, we tried to classify the people with different organizational commitment personality trait through EEG. Firstly, we organized the participants to complete the organizational commitment questionnaire and recorded their resting state EEG. We divided 10 subjects into two classes (positive and negative) according to the questionnaire scores. Then, various EEG features including power spectral density, microstate, functional brain network and nonlinear features from segmented EEG sample were extracted as the input of different machine learning classifiers. Next, several evaluation metrics were used to evaluate the results of the cross-validation experiment. Finally, the results show that the EEG power in α band, the weighted clustering coefficient of functional brain network and the Permutation Entropy of EEG are relatively good features for this classification task. Furthermore, the highest classification accuracy rate can reach 79.9% with 0.87 AUC (the area under the ROC). The attempts in this paper may serve as the basis for our future research.

The construction and installation engineering of floating offshore wind turbines is important to minimize schedules and costs. Floating offshore wind turbine substructures are an expanding sector within renewable power generation, offering an opportunity to deliver green energy, in new areas offshore. The floating nature of the substructures permits wind turbine placement in deep water locations. This paper investigates the construction and installation challenges for the various floating offshore wind types. It is concluded that priority areas for project management and design engineers minimising steel used in semi submersible construction, reducing the floating draft of Spars and for Tension Leg Platforms developing equipment for a safe installation. Specifically tailored design for construction and installation includes expanding the weather window in which these floating substructures can be fabricated, transported to and from offshore site and making mooring and electrical connection operations simpler. The simplification of construction methodology will reduce time spent offshore and minimise risks to installation equipment and personnel. The paper will include the best practice for ease of towing for offshore installation and the possible return to port for maintenance. The construction and installation process for a floating offshore wind turbine varies with substructure type and this will be developed in more detail in the paper. Floating offshore wind structures require an international collaboration of shipyards, ports and construction vessels, though to good project management. It is concluded that return to port for maintenance is possible for semi submersibles and barges whereas for Spars and TLP updated equipment is required to carry out maintenance offshore. In order to facilitate the construction and to minimize costs, the main aspects have to be considered i.e., the required construction vessel types, the distance from fit-out port to site and the weather restrictions.

As the density of the high-speed railway network continues to increase, the problem of electromagnetic interference on adjacent lines has become increasingly prominent. This paper focuses on the electromagnetic interference of adjacent lines caused by rail and line in the signal transmission process of the high-speed rail track circuit. Firstly, complete the establishment of the four-terminal network model of the ZPW-2000A track circuit system and the cab signal entry current crosstalk model, calculation of interference voltage under different parallel length of signal frequency. Then the interference factors and coupling mechanism of adjacent lines are analysed to realize calculation of interference amount. Finally, according to the sensitivity index of the cab signal, the maximum parallel length of adjacent sections is given respect, and the interference protection suggestions of adjacent lines are put forward. The research work of this paper provides a theoretical basis for suppressing the interference of adjacent lines and guarantees the safe and efficient operation of high-speed trains.

The Spectre attacks exploit the speculative execution vulnerabilities to exfiltrate private information by building a leakage channel. Creation of a leakage channel is the basic element for spectre attacks, among which the cache-tag side channel is considered to be the most serious one. To block the leakage channels, a novel cache applies Dynamic Mapping technology, named DmCache, is presented in this paper. DmCache applies a dynamic mapping mechanism to temporarily store all the cache lines polluted by speculative execution and keep invisible when accessing. Then it monitors the head of the reorder buffer to determine which polluted cache line can become visible. In this paper, we demonstrated that Spectre attacks exerted no impact on a processor system equipped with DmCache based on the analysis of the processor’s circuit behaviour, which equipped with the DmCache and under the Spectre attack.

Mechanical errors seriously affect the transmission performance of mechanical structure, especially for high-precision mechanical structure. With the development of virtual simulation technology, the performance test of mechanical structure in virtual environment is gradually applied. Under the background, this paper takes the movable tooth reducer as the research object and puts forward a virtual performance test method by combing test errors with virtual simulation technology. The tooth profile errors of key components of the reducer are obtained by optical scanning, and the simulation test is carried out. Meanwhile, the accuracy of the simulation test is verified by the implementation of vibration test. The results show that both the simulated vibration acceleration and the experimental test vibration acceleration show a double-peak variation trend, and the frequency difference between the two peaks is less than 5%. Therefore, the simulation test method proposed in this paper can effectively evaluate the performance of mechanical structures.

The continuous development of mineral resources is increasingly damaging the ecological environment, so it is of great significance to ecological restoration and dynamic monitoring of the mining area. In this paper, dynamic monitoring and evaluation method of ecological restoration in the mining area are proposed, which integrates GNSS + RS (Global Navigation Satellite System + Remote Sensing) technology. According to the Precipitable Water Vapor (PWV) retrieved by GNSS and NDVI (Normalized Vegetation Index) can monitor the ecological environment and introduce machine learning to improve the accuracy of the model. The dynamic assessment of ecological restoration was carried out by using temperature, rainfall, NPP (Net Primary Productivity), NDVI and PWV. The results show that: (1) the modeling effect of machine learning is better than that of the least square regression. (2) The comprehensive ecological evaluation index proposed can better reflect the ecological situation of the mining area. Therefore, the environmental monitoring and assessment of mining area based on GNNS + RS technology proposed in this paper have important reference significance.

During the heating period, the thermal storage electric boiler helps the thermal power units to participate in the deep peak regulation by converting the electric energy into heat energy for heating users, but in the non-heating period, the thermal storage electric boiler can not operate because there is no heat user, as a result, the thermal storage electric boiler is shut down in summer, and can not assist the thermal power unit to participate in the deep peak regulation. Therefore, this paper designs an electric thermal storage boiler regenerative system for peak shaving in summer. In this regenerative system, electric boiler is used to heat circulating water in heating period, and electric boiler is used to heat condensed water in non-heating period, and in the non-heating period, the number of low-pressure heaters can be adjusted according to the load and heat storage capacity of the units, so that the electric boiler can assist the thermal power units to participate in the deep peak regulation throughout the year, taking a 350MW unit with 70MW regenerative electric boiler as an example, the heat exchange capacity is calculated to verify the feasibility of the regenerative system. In this paper, a new method of heating condensate by regenerative electric boiler in non-heating period is proposed to solve the problem that the new energy can not be used and the energy is wasted in summer.