rss_2.0Engineering FeedSciendo RSS Feed for Engineeringhttps://www.sciendo.com/subject/ENhttps://www.sciendo.comEngineering Feedhttps://www.sciendo.com/subjectImages/Engineering.jpg700700Hardware accelerated image processing on FPGA based PYNQ-Z2 boardhttps://sciendo.com/article/10.2478/cjece-2021-0004<abstract> <title style='display:none'>Abstract</title> <p>In this paper we present the partial results of a research in progress made in order to develop a prototype of a self-driving car’s controller and processing unit. The framework that we used consisted of a camera for input of visual imagery information (Logitech 720p), a laser range finder for depth and object sensing (Parallax; PulsedLight LIDAR-Lite v2), and the main processing board, an FPGA based accelerator board PYNQ Z2.</p> </abstract>ARTICLE2021-10-16T00:00:00.000+00:00Increasing Energy Efficiency Using Photovoltaic Panelshttps://sciendo.com/article/10.2478/cjece-2021-0002<abstract> <title style='display:none'>Abstract</title> <p>The paper analyses the way of design of photovoltaic systems. The objective of this paper is to study the production capacity of electrical energy and the way it is influenced by real time conditions. In order to realize some energetic models that could be implemented on a large scale and used as a model of good practice we used photovoltaic systems of 3 dimensions: 60 PV panels, 100 PV panels and 160 PV panels respectively. The present study considered the climate conditions of the city of Cluj-Napoca for 12 months. It considered the consumption profile (hourly consumption) and the period of the year (summer, winter, etc.) for 3 typical buildings. We used Matlab/Simulink software for simulations. The result is an estimation of the production of electrical energy for renewable sources and the reduction of GreenHouse Gases (GHG). The aim is to reduce both GHG and the energy consumption from conventional sources.</p> </abstract>ARTICLE2021-10-16T00:00:00.000+00:00Audio Database for TIAGo Service Robothttps://sciendo.com/article/10.2478/cjece-2021-0001<abstract> <title style='display:none'>Abstract</title> <p>In this paper we present an updated version of the audio database acquired by the TIAGo service robot and by the simulated TIAGo service robot. To the initial database which consists in 1380 audio signals we have added 1920 more acoustic signals. The audio database consists now in 3300 isolated audio events corresponding to 110 classes. All the recorded sound events correspond to the indoor environment, and they are spread into five different scenarios: kitchen, room, appliances, voice and non-verbal. The audio database is intended to be used in order to identify indoor events based on audio signature, especially when elderly or chronically ill people live alone.</p> </abstract>ARTICLE2021-10-16T00:00:00.000+00:00Security System Aided by Voice Fingerprinthttps://sciendo.com/article/10.2478/cjece-2021-0005<abstract> <title style='display:none'>Abstract</title> <p>The goal of this paper is to create a security system to identify a specific person who wants to access private information or enter a building using their voice. To perform this system, we identified a database containing the audio files of the users who will be able to authenticate with this system. Several steps were sequentially performed in order to extract the characteristics of the Mel Frequency Cepstral Coefficients from the audio files. Based on the k-Nearest Neighbor algorithm with an Euclidean distance and 4 neighbors, a training model was created. Through experimental results we prove in two ways, using confusion matrix and scatter plot, that the overall voice fingerprint recognition is 100%, for this particular configuration.</p> </abstract>ARTICLE2021-10-16T00:00:00.000+00:00Designing a Low-Code CRUD frameworkhttps://sciendo.com/article/10.2478/cjece-2021-0003<abstract> <title style='display:none'>Abstract</title> <p>Nowadays programmers write source code for inserting, editing and deleting records of a relational table. The majority of commercial relational databases include a specific management tool that offers such possibilities and most database programmers take this ability as granted. When it comes to real life applications, programmers use Object Oriented (OO) paradigm to build user friendly windows/screens/forms for database operations. The current work shows a different approach using a Low-code CRUD (Create, Read, Update, Delete) framework. Views and guidelines of how to design a Low-code CRUD framework will be detailed. “Low-code” motivation is due to the fact that the new framework will provide the ability to use less code in order to build fast and efficient complex applications. It will be up to the reader to envision a specific framework.</p> </abstract>ARTICLE2021-10-16T00:00:00.000+00:00Effect of Different Yarn Combinations on Auxetic Properties of Plied Yarnshttps://sciendo.com/article/10.2478/aut-2021-0045<abstract><title style='display:none'>Abstract</title><p>This study presents the effects of a novel plied yarn structure consisting of different yarn components and yarn twist levels on the Poisson's ratio and auxetic behavior of yarns. The plied yarn structures are formed with bulky and soft yarn components (helical plied yarn [HPY], braided yarn, and monofilament latex yarn) and stiff yarn components (such as high tenacity [HT] and polyvinyl chloride [PVC]-coated polyester yarns) to achieve auxetic behavior. Experimental results showed that as the level of yarn twist increased, the Poisson's ratios and the tensile modulus values of the plied yarns decreased, but the elongation values increased. A negative Poisson's ratio (NPR) was obtained in HT–latex and PVC–latex plied yarns with a low twist level. The plied yarns formed with braid–HPY and braid–braid components gave partial NPR under tension. A similar result was achieved for yarns with HT–latex and PVC–latex components. Since partial NPR was seen in novel plied yarns with braided and HPY components, it is concluded that yarns formed with bulky–bulky yarn components could give an auxetic performance under tension.</p></abstract>ARTICLE2021-10-15T00:00:00.000+00:00Industry and Research: New Collaborative Perspectives in the Industry 4.0 Erahttps://sciendo.com/article/10.33894/mtk-2021.14.03<abstract> <title style='display:none'>Abstract</title> <p>The paper presents some challenges of developing DIHs (Digital Innovation Hubs) based on the Industry 4.0 principles in Transylvania (Romania). DIHs have proven to be successful as knowledge transfer centers especially in information technologies, but they are still a novelty in the field of manufacturing technologies and industrial engineering in many regions. The paper presents conceptual possibilities of developing a manufacturing technology based DIH in Romania, based on cooperation among local organizations.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00Thermal Behaviour Analysis of Complex Joints for an Energy Efficient School Buildinghttps://sciendo.com/article/10.33894/mtk-2021.14.06<abstract> <title style='display:none'>Abstract</title> <p>Energy-efficient buildings have received increasing attention in recent times as they represent a direction that promotes the objectives of a sustainable, competitive and decarbonized energy policy. In order to meet the minimum requirements of the nearly zero-energy buildings (nZEB) the thermal characteristics of the envelope play an important role. The aim of the paper is to present and analyse the thermal behaviour of complex joints for an energy efficient school building, for which the formation of thermal bridges has been reduced by applying improved geometrical and technological solutions. Since most of the thermal bridge catalogues did not provide updated details for the studied joints, numerical calculations, as two-dimensional finite elements thermal simulations, were performed to determine thermal transmittance coefficients and the U-value..</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00Applicability of Procedural Variants in Ultrasonic Testinghttps://sciendo.com/article/10.33894/mtk-2021.14.01<abstract> <title style='display:none'>Abstract</title> <p>Ultrasonic testing (UT) is essentially the transmission of high-frequency (0.25…20 MHz) sound waves (mechanical vibration and energy) into a material, in order to interact with the macro-structural constituents of the material which reflect and/or weaken it. Ultrasonic testing – as one of the most common nondestructive material testing (NDT) methods – thanks to its many variants, is able to operate in a mobilized and highly automated fashion; it can be performed on most material types; high accuracy and reproducibility can be achieved in error detection, and it is generally enough if only one side is accessible; changes in elevation can also be verified with this method besides distance measurement, and it is also suitable for determining certain material characteristics. The present article reviews the application technology characteristic of the procedural variants.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00The Improvement of the Precision of the Archimedean Spiral Toothline Gear Cutting Millhttps://sciendo.com/article/10.33894/mtk-2021.14.04<abstract> <title style='display:none'>Abstract</title> <p>The precision of gears has a major influence on the quality of the transmission. If the gear cannot be finished by grinding, the precision of the generating tool becomes essential. Archimedean spiral toothline cylindrical gears are obtained by reciprocate meshing using a milling cutter built up by individual cutters, organized in groups. The profiles of edges must be realized with a minimal profile error. In order to ensure the quality and the precision of the meshed tooth surface, and also the profile constancy after re-sharpening, relief faces must be realized by a grinding relieving operation. A secondary effect of the kinematics of relieving end the spatial extent of the grinding wheel a post undercut results and this produces an inevitable profile error. The present paper discusses a possible grinding wheel setting that produces a maximum theoretical profile error under 1μm along the whole re-sharpening reserve of the cutter. The proposed setting can be realized on a classical relieving lathe.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00Control of an Electric Vehicle Hybrid Energy Storage Systemhttps://sciendo.com/article/10.33894/mtk-2021.14.12<abstract> <title style='display:none'>Abstract</title> <p>In electric vehicles battery life can be prolonged by using hybrid energy storage systems (HESS ), which combine high energy density batteries with supercapacitors, characterized by high power density. This paper deals with the control of electronic power converters from an active parallel HESS. The load of the HESS is the electrical motor drive of an electric vehicle. The interfaces between the DC-link and the power sources are four-phase bidirectional DC-DC converters driven in current control mode, based on the current references supplied by an active parallel HESS power distribution algorithm. We present a rule-based fuzzy energy management algorithm for a HESS powered electric vehicle and its simulation in MATLAB/Simulink<sup>®</sup> environment using the Quasi-Static Simulation (QSS ) and Fuzzy Logic toolboxes. Also, simulation results in driving and regenerative braking operation modes of the electric vehicle are presented.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00An Analysis of Manufacturing Precision of Involute Worms Using a Kinematical Modelhttps://sciendo.com/article/10.33894/mtk-2021.14.07<abstract> <title style='display:none'>Abstract</title> <p>The manufacturing precision of involute worms constitutes a major requirement. On the one hand, the worm constitutes the input element of the worm drive; secondly, the involute helical surface is the basic surface of an involute worm-hob. This paper presents an analytic comparison between the involute surfaces obtained using theoretical equations, kinematic simulation of the cutting and the surface charged with errors. The surface error is considered the distance along the normal direction to the theoretical surface, measured between this and the surface charged with simulated manufacturing errors. The main sources of errors are considered the center-error of the edge plane, the edge profile error and deviation of the axial feed direction from the axis of the worm. The theoretical results allow us to conclude that the influence of the edge profile error is the largest. It is followed by the parallelism error between the feed direction and the axis of the worm, and finally, the center error of the tool edge.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00The Story of a Re-Operating Windmillhttps://sciendo.com/article/10.33894/mtk-2021.14.02<abstract> <title style='display:none'>Abstract</title> <p>Research on the history of the development of grain milling structures is a priority topic of the Department of Technical Sciences of the Transylvanian Museum Association. Quite a few publications and study volumes contain the results of the research. The present dissertation presents another grinding structure, the windmill, its reconstruction, creating a connection between the theoretical foundations and the practical implementation. Although it was built as a museum and tourist object, it is also a significant work from the point of view of technical history.</p> <p>The Felsőszentiván windmill is powered by a 14-meter-diameter windmill. The mill has a two-stage accelerator gear that increases the low, non-grinding speed of the wind turbine for the rotation typical of grindstone mills.</p> <p>The upper stones of a pair of grindstones rest on a vertical axis, and by raising this the gap between the stones can be adjusted. This determines the particle size of the grind. The windmill consists of three functional parts: a windmill, an accelerator gear and a grain mill made up of a pair of grindstones.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00The Conditions of Undercut By Shaping Using a Rounded Profile Gear Shaper Cutterhttps://sciendo.com/article/10.33894/mtk-2021.14.05<abstract> <title style='display:none'>Abstract</title> <p>The present paper deals with the cases of undercut when not only the linear but the curved segment of the generatrix curve is also taken in consideration. The literature admits the approximation of the root fillet with a circular arc with a radius of 0,38 m. In this paper, instead of this approximation, the real envelope realized by the rounded rack-head is computed. In analyzing the undercut there are two classical synthetic geometrical models supporting Litvin’s general equations that describe the condition of avoiding the undercut: one for the linear and one for the rounded part of the generatrix. The scope of exact computing of the root fillet curve consists in optimizing the cutting toll tooth topland geometry to obtain the best rigidity. The numerically evaluated models allow us to conclude that profile shifting can be pushed below the undercut limits stated in the classical literature, without the appearance of the well-known fracture point on the meshed tooth profile.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00Study of Three-Point Linkage of Power Machinehttps://sciendo.com/article/10.33894/mtk-2021.14.09<abstract> <title style='display:none'>Abstract</title> <p>The three-point linkage serves to interconnect the power machine and the suspended or semi-suspended work machine. It has a role in the operation of the machine group, in towing and in the setup of the machines. Part of the weight of the suspended machine is loaded on the driven wheels, thus increasing the adhesion weight which results in an increase in the tractive force. Understanding the operation of this equipment it is necessary for horticulture, agronomy and landscape architecture future engineers. In this thesis we model the effect of connection points of the three-point linkage on the tractive force in a specific case: that of the suspended plow.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00Reliability Question of New Material Used in Vehicle Engineeringhttps://sciendo.com/article/10.33894/mtk-2021.14.11<abstract> <title style='display:none'>Abstract</title> <p>In-vehicle engineering, several types of materials can be used to build vehicles of different sizes and for different uses. Traditionally those materials can be iron, aluminium, steel, rubber, glass, copper, leather, and others. These materials have been in constant development over the years, and this development has accelerated during the last ten years as manufacturers strive to compete on the issue of reliability of these new innovative materials. Reliability requires the production of materials with minimal (or well-known) variations in properties or dimensions. Parts made from these materials must be manufactured using processes that have also been proven to be reliable. This aim of this paper is to explain how reliability criteria can only be obtained if there are means of control suited to the most used materials (metals and polymers).</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00Investigations of Surface Qualities of Wire EDM Machined Tool Steelshttps://sciendo.com/article/10.33894/mtk-2021.14.10<abstract> <title style='display:none'>Abstract</title> <p>In the EDM process an electrical discharge occurs between an anode (graphite or copper) and a cathode (material to be machined) in a dielectric medium. Developments in EDM technologies have opened a new path towards high-precision, more productive machining of high alloyed, high hardness and high strength steels [1]. Wire EDM offers an efficient and cost effective alternative to traditional machining in tool and component manufacturing [2]. EDM machining removes electrically conductive material with rapid and repetitive spark emissions using a dielectric fluid. As a result, the surface of the raw material is subject to erosion. The quality of the machined surface depends to a large extent on the parameters of the machining technology [3]. In the testing experiments, wire EDM machining was performed on two tool steel grades using different machining parameters. After each machining step, hardness and roughness tests were performed on the surface of the workpiece. Scanning electron microscopy was performed on the machined surface. The tests confirmed that the surface quality of the tools is significantly influenced by the parameters set during the EDM. The change of parameters was achieved by performing multiple cutting threads. By using the multiple cutting thread, tools with favourable surface roughness have been produced for tool steels with a high hardness of quenched and tempered heat treatment state.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00Design and Wind Simulation of Steel Structures in a Parametric Environmenthttps://sciendo.com/article/10.33894/mtk-2021.14.08<abstract> <title style='display:none'>Abstract</title> <p>Nowadays, parametric design and various simulation methods are gaining ground in almost every engineering and creative profession. This paper investigates the practical applicability of the combination of these methods, by analysing a specific free-form structure with Grasshopper 3D and OpenFOAM and points out the differences between the results of a CFD simulation and the recommended methods of the Eurocode, highlighting the new perspectives that are opening up in the field of structural design, especially in the examination of wind effects.</p> </abstract>ARTICLE2021-08-05T00:00:00.000+00:00The Evaluation of Expanded Uncertainty of DC Voltages in the Presence of Electromagnetic Interferences using the LabVIEW Environmenthttps://sciendo.com/article/10.2478/msr-2021-0019<abstract> <title style='display:none'>Abstract</title> <p>The paper presents a possible application of integrated LabVIEW environment to the final evaluation of measurement results in direct measurement. The possibilities of presenting and visualizing the uncertainty of measurement results in a convenient and user-friendly form are also discussed. The topics discussed in the paper were presented using a developed application in LabVIEW. The paper discusses the topic of measurement of direct voltages in the presence of strong electromagnetic interferences. These problems are frequently omitted or hardly emphasized. It presents a suitable measuring system, a virtual measuring instrument created in the LabVIEW environment, and the results of tests carried out for an example NI PCI-6221 data acquisition board. The described approach can be applied also in other measurement situations.</p> </abstract>ARTICLE2021-09-17T00:00:00.000+00:00Mixed-mode Method Used for Pt100 Static Transfer Function Linearizationhttps://sciendo.com/article/10.2478/msr-2021-0020<abstract> <title style='display:none'>Abstract</title> <p>Pt100 is a resistance temperature detector characterized by a relatively linear resistance/temperature relationship in a narrow temperature range. However, the Pt100 sensor shows a certain degree of static transfer function nonlinearity of 4.42 % in the range between −200 °C and 850 °C, which is unacceptable for some applications. As a solution to this problem, a mixed-mode linearization method based on a special dual-stage piecewise linear ADC design is proposed in this paper. The first stage of the proposed dual-stage piecewise linear ADC is performed with a low-complex and low-power flash ADC of a novel sequential design. The novelty of the proposed sequential design is reflected in the fact that the number of employed comparators is equal to the flash ADC resolution. The second stage is performed with a delta-sigma ADC with a differential input and differential reference. Using the 6-bit flash ADC of novel design and the 24-bit delta-sigma ADC, the nonlinearity error is reduced to 2.6·10<sup>−3</sup> %, in the range between −200 °C and 850 °C. Two more ranges are examined, and the following results are obtained: in the range between 0 °C and 500 °C, the nonlinearity error is reduced from 1.99 % to 5·10<sup>−4</sup> %, while in the range between −50 °C and 150 °C, the nonlinearity error is reduced from 0.755 % to 2.15·10<sup>−4</sup> %.</p> </abstract>ARTICLE2021-09-17T00:00:00.000+00:00en-us-1