rss_2.0Engineering FeedSciendo RSS Feed for Engineering Feed three-phase switched-capacitor-based MLI<abstract> <title style='display:none'>Abstract</title> <p>This article proposes a novel three-phase inverter based on the concept of switched capacitors (SCs), which uses a single DC source. A three-phase, seven-level line-to-line output voltage waveform is synthesised by the proposed topology, which includes eight switches, two capacitors, and one diode per phase leg. The proposed topology offers advantages in terms of inherent voltage gain, lower voltage stresses on power switches, and a reduced number of switching components. Additionally, the switched capacitors are self-balanced, thereby eliminating the need for a separate balancing circuit. The proposed structure and its operating principle, the self-balancing mechanism of the capacitors, and the control strategy are all thoroughly explained in the article. The proposed topology has also been compared with some recent SC topologies. Lastly, the proposed topology has been shown to be feasible through simulation and experimentation.</p> </abstract>ARTICLE2022-09-25T00:00:00.000+00:00Extreme Rainfall-Runo Events Modeling Using HEC-HMS Model for Oued El Hachem Watershed, Northern Algeria<abstract> <title style='display:none'>Abstract</title> <p>Flood forecasting has become necessary for dam management during extreme hydrological events. The lack of streamflow data in ungauged watersheds of arid and semi-arid regions makes the assessment of water resources di cult. In this paper, the Hydrologic Modeling System developed by the Hydrologic Engineering Center (HEC-HMS) was applied to the Oued El Hachem watershed. Calibration and validation of the model have been performed, taking into account the lag time and the curve number CN that is expressed as a function of soil group, land use and antecedent runo condition. The model was evaluated on the basis of the coe cient of determination, the Nash Sutcli e E ciency (NSE), and the percentage di erences between peak and volume. Performance indices of calibration showed a good agreements between observed and computed flows. The validation of the model has given satisfactory results. The calibrated model can be used to manage the dam of Boukerdane during extreme rainfall events by forecasting the induced hydrographs from which adequate procedures will be operated in order to ensure the safety of the dam against possible overtopping.</p> </abstract>ARTICLE2022-09-25T00:00:00.000+00:00Numerical Model and an Analysis of Inertial Accumulator Operation Under Selected Working Conditions<abstract> <title style='display:none'>Abstract</title> <p>The aim of this paper was to create a computational model that will enable the evaluation of the operation of a conventional inertia accumulator. This is an issue that is relevant as storage of energy is becoming increasingly important, in particular when it comes to generating electricity from renewable sources. In the course of the conducted works, an analytical model was developed based on the available literature, and then, it was introduced into the environment for numerical calculations. Four variants resulting from different geometrical parameters of the flywheel were adopted successively. On this basis, a series of simulations were performed, which allowed for obtaining the characteristics of the analysed solutions. As a consequence, a number of characteristics related to the mechanical power and energy of the simulated kinetic energy accumulators were obtained. The test results therefore provide a basis for comparing kinetic energy accumulators with different geometries and drive solutions.</p> </abstract>ARTICLE2022-09-25T00:00:00.000+00:00Experimental and Numerical Investigations and Optimisation of Grain-Oriented Silicon Steel Mechanical Cutting Process<abstract> <title style='display:none'>Abstract</title> <p>The process of mechanical cutting of magnetic materials has many advantages in the form of high efficiency with reduced process costs in relation to other cutting technologies; no thermal stresses in the material, which significantly deteriorate the magnetic properties; or the possibility of shaping materials taking into account long cutting lines. In industrial practice, it is very difficult to ensure appropriate conditions for the cutting process and its proper control. Currently, there are no data on the selection of technological parameters of the mechanical shear slitting process of grain-oriented silicon steel in terms of the obtained cutting surface quality and the obtained magnetic properties of the workpiece. The article presents the possibilities of forecasting the characteristic features of the cut edge and selected magnetic properties of grain-oriented silicon steel. For this purpose, proprietary numerical models using FEA (Finite Element Analysis) were used. Then, experimental studies were carried out, and the optimisation task was developed. The developed results enable the correct selection of technological parameters of the process, ensuring the appropriate quality of the cut edge of steel and minimal interference with the magnetic properties.</p> </abstract>ARTICLE2022-09-25T00:00:00.000+00:00Generalized Differential Mathematical Model in Stator Reference Frame for PMSM and VRSM Simulation<abstract> <title style='display:none'>Abstract</title> <p>The paper presents the deduction of a novel decoupled form (considering the differential current quantities) of the differential mathematical model in stator reference frame, useful for numeric simulation of control approaches for PMSM (permanent magnet synchronous machines) generalized for both IPMSM and SPMSM (salient and non-salient PMSM). The model is confirmed to be equivalent to the well-known model defined in the rotor synchronous reference frame using a Matlab-Simulink implementation that is verified and validated by simulation during which the power/energy conservation is monitored and the system states’ evolution is compared to the reference model in rotor reference frame using a generator structure.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Evolution of the Manufacturing Technology of Photovoltaic Panels and Factors Affecting their Performance<abstract> <title style='display:none'>Abstract</title> <p>The efficiency of the production of electricity from solar energy depends on technological developments and the performance of the photovoltaic panels. A positive trend depends on diversifying the materials used to manufacture plates and adapting them to the climatic conditions. The article presents several technological aspects to give an idea about the evolution of the yields of photovoltaic panels, especially about the photovoltaic technology in the first, the second, and third generations. After the statement of the main characteristics of the photovoltaic panels, an analysis of the factors that can affect their performances and can create difficulties in implementing projects is made. This approach aims to choose the most advantageous combination of concepts and techniques when making photovoltaic parks.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Environmental Performance Evaluation for a Small Scale Trigeneration System<abstract> <title style='display:none'>Abstract</title> <p>The modern buildings must have very high standards and require highly efficient energy supply systems due to space limitations for renewable installations. Electricity and thermal energy can be produced simultaneously with a photovoltaic-thermal (PVT) system. In the paper, an innovative concept of PVT system for a hospital is studied. PVT collectors serve as both a heat source and a heat sink for a reversible heat pump in the examined system. Due to the reduced electricity consumption from the network for heat rejection, the overall efficiency was improved by using a reversible water-to-water heat pump as heat and cold source compared to a conventional solar cooling system. Primary energy savings can be achieved with a maximum utilization of PV for electricity, heating and cooling (as air conditioning). The paper presents an original methodology for determining the environmental impact of the real PVT operation. The case study shows that for a real 4kWp PVT, the yearly energy savings reduce the greenhouse gas (GHG) emissions with 281.8 kg/year for SO<sub>2</sub> and 152.4 for CO<sub>2</sub>.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Transient Residual Voltage Influence on the Dynamic Load Transfer<abstract> <title style='display:none'>Abstract</title> <p>The successful operation of back-up supply sources in the case of dynamic loads transfer in industrial electricity supply installation is mainly depending on the mitigation of the residual voltage that appears in fault scenarios that result in losing supply from the main grid. The decrease of the interval of presence of residual bus voltage depends highly on the local load and the network configuration. A high time constant (seconds) of the decreasing residual voltage can lead to the disconnection of critical consumers. In this paper, it is presented a simple, cost-effective method for dynamic load transfer that can replace the Motor Bus Transfer approach. The validity of the method is tested on a real large industrial site from Romania. The case study shows that the proposed approach can achieve a voltage return time of around 750 ms.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Application of Association Rule Mining in Preventing Cyberattacks<abstract> <title style='display:none'>Abstract</title> <p>Designing a security solution should rely on having a good knowledge of the protected assets and better develop active responses rather than focus on reactive ones. We argue and prove that malicious activities such as vulnerabilities exploitation and (D)DoS on Web applications can be detected during their respective initial phases. While they may seem distinct, both attack scenarios are observable through abnormal access patterns. Following on this remark, we first analyze Web access logs using association rule mining techniques and identify these malicious traces. This new description of the historical data is then correlated with Web site structure information and mapped over <italic>trie</italic> data structures. The resulted <italic>trie</italic> is then used for every new incoming request and we thus identify whether the access pattern is legitimate or not. The results we obtained using this proactive approach show that the potential attacker is denied the required information for orchestrating successful assaults.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00GDPR Records of Processing Activities for Data Controllers<abstract> <title style='display:none'>Abstract</title> <p>Data controller organizations are required to keep an up-to-date and detailed list of their processing activities and be prepared to show that list to regulators upon request. This list should include at least the purposes of the processing, the target data and all the parties involved in handling that data. We present a solution for organizing all these information into both relational and non-relational document-oriented databases to facilitate such reports. A technical approach of auditing the implementation degree of the rules introduced by the EU GDPR will better prepare the data controllers in complying to this Regulation. We consider a top-down methodology for processing raw data addressing several types of organizations, with different organizational structures. For all these entities we focus on processes, activities, classes of documents collected and personal data. All these data constitute the basis of the “Records of processing activities” required by the Regulation.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Application of Spectral Analysis in Spinning Measurements<abstract> <title style='display:none'>Abstract</title> <p>The presented analysis concerns the problem of irregularity in the mass distribution in linear textile products, its impact on the quality of flat products, and the methods of assessment. Based on the model of the ideal fiber stream, the purpose of the spectrogram has been justified, the characteristic form of the spectrogram for the yarn, roving, and sliver has been presented, and the impact of spinning machines on the form of the spectrogram has been described. The paper evaluates also the selected aspects of spectral analysis of the yarn and spinning semi-finished product irregularities.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00False actions of the aviation fire protection system caused by disturbances in power circuits<abstract> <title style='display:none'>Abstract</title> <p>The article presents the results of simulation tests of the SSP-FK aviation fire protection system and the identification of the main causes of its false operation on many airplanes and helicopters of the Polish Armed Forces with the use of a diagnostic simulator built at ITWL. The results of the performed statistical analyzes pointing to the execution blocks as the key factors in false fire signaling are discussed. Selected test results of the developed simulation model of the actuator unit under the conditions of disturbances occurring in its supply circuits (in particular instantaneous voltage drops) are presented. The effectiveness of the presented test method with the use of a simulation model of a fire protection system, which can be used to train the engineering and aviation service and pilots, and to support the work of the Aircraft Accident Investigation Commission, was pointed out.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Case Study of the Psychophysical State of Student-Operators During UAVO Training, Based on Heart Rate Parameter<abstract> <title style='display:none'>Abstract</title> <p>This article focuses on the human factor in UAV operations. In the manuscript, research on the psychophysical state of student-operators under the license of UAVO VLOS &lt;4 kg. For the analysis of the psychophysical state, the pulse parameter was used, which is one of the values that describe the work of the cardiovascular system and is one for the objective methods of assessing the psychophysical state of a human being. The data collected were analyzed using the STATISTICA software. The article focuses on the above aspect and analyzes the psychophysical state of the student-operator during flight training. The obtained results were also related to research on similar topics in the chapter discussion section.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Influence of the Bird Model Shape on the Results of Numerical Analyses of Bird Models Impact Against a Rigid Plate<abstract> <title style='display:none'>Abstract</title> <p>This paper presents results of numerical analyses of different bird models impacting a rigid plate. The results of the study were compared with findings derived from experimental research. The experimental studies were conducted using a dedicated gas gun kit. A gelatine projectile was used as a bird model, giving it a speed of 116 m/s. For the purpose of the numerical investigations, the authors used the LS-DYNA software package. It is a computational code for the analysis of fast-variable phenomena using different methods, such as Lagrange, Arbitrary Lagrange-Euler (ALE), Smoothed Particle Hydrodynamics (SPH). Three cylindrical bird models with different endings were developed using the SPH method. The shape of the end of the bird model was found to exert a significant effect on the Hugoniot pressure values. However, it does not affect the maximum value of the impact force. The differences only occurred at the initial moment of impact, which was related with the area of contact between the model end and the target.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Quantitative Assessment of the Influence of Plasma Hardfacing Parameters on the Metallurgical Melting of an Austentic Steel Coating with a Substrate Material Made of C45 Steel<abstract> <title style='display:none'>Abstract</title> <p>In this paper, based on a quantitative analysis of the parameters of plasma hardfacing of C45 steel with CastoMag 45554S wire, an optimisation of the hardfacing process parameters has been carried out. Experimental researches were carried out on the basis of an orthogonal plan, and the optimum hardfacing parameters, e.g.: intensity, voltage, wire feeding speed, were determined by the multiple regression method and the Taguchi method. It was found that the main current of the plasma arc had the greatest influence on the value of the fusion index. The highest S/N value was obtained for the following parameters: I = 120 A, U = 31 V, vn = 0.75 m/min, vd = 3.9 m/min, z = 12 mm.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Developing Technology for the Welding of Steam Turbine Steering Diaphragms Using the Submerged Arc Welding Method<abstract> <title style='display:none'>Abstract</title> <p>The production process of steam turbine steering disks requires many welded joints of high quality parameters. The article presents the test results obtained in the welding process of elements made of martensitic steel X11CrMo12-1 with a thickness of 160 mm. During the tested process, a weld was made with a welding wire filling with 1% and 9% chromium in the K geometry, a groove height of 65 mm and without full penetration. The research was carried out on a butt joint in a downward position. The joint was subjected to destructive and non-destructive tests, including macroscopic tests. This work was aimed at determining the optimal welding parameters, influencing the improvement of the properties and quality of the joint..</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Influence of Reduced Cutting Speed Values on Operator Safety and Cutting Tool Life in the Processes of Manufacturing and Regeneration of Marine Machinery Parts<abstract> <title style='display:none'>Abstract</title> <p>The research used shafts made of X5CrNi18-10 (AISI 304L) stainless steel, which is used, among others in the shipbuilding industry. The turning process was carried out on the CU500MRD universal lathe with the use of cutting inserts with a corner radius of 0.2; 0.4 and 0.8 mm. The measurement of the forces during machining was recorded using a Kistler dynamometer. Surface roughness measurements were made with a Waveline W20 profilometer. The research results are the basis for determining the safe range of application of stainless steel cutting parameters on conventional lathes, with the simultaneous analysis of the quality of the machined surface.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00The Use of Acoustic Emission to Determine the Safe Load Range of GFRP Composites Used in Ship and Aviation Structures<abstract> <title style='display:none'>Abstract</title> <p>The article presents the methodology and results of strength tests with simultaneous registration of acoustic emission. The subject of the research were glass fibre-reinforced plastics (GFRP) made by hand lamination. The obtained results allows to identify the stresses characteristic of the individual stages of the material failure process. These results can be the basis for determining the safe scope of application of the mentioned materials, especially helpful at the stage of designing ship and aircraft structures. The analysis of the test results allows to determine the safe level of stresses not exceeding about 70 MPa.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00The Analysis of Properties Selected Filaments for Making Components and Parts of Marine Equipment by Fused Deposition Modeling on Example of Flexible Clutch Coupling and Oil Centrifuge Scroll<abstract> <title style='display:none'>Abstract</title> <p>Incremental techniques (FDM) were used to create prototype of flexible clutch coupling and oil centrifuge scroll. We carried out preliminary research of stretching, compressing and hardness material in different degree of filling. The results of our research allows to select materials which are necessary to create flexible clutch coupling and oil centrifuge scroll.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00Influence of Pressure Changes on the Viscosity of Lubricating Oil in CFD Simulations of Conical Bearing Hydrodynamic Lubrication<abstract> <title style='display:none'>Abstract</title> <p>The aim of this study is to consider the effect of pressure on the viscosity of lubricating oil in the adopted model of hydrodynamic lubrication and on the calculated flow parameters and operating parameters of a conical slide bearing. The numerical analysis consisted in solving the Reynolds type equation for the process of stationary hydrodynamic lubrication.</p> </abstract>ARTICLE2022-09-22T00:00:00.000+00:00en-us-1