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Search results for: DC MICRO GRID
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Syntactic modular decomposition of large ontologies with relational database
PublicationSupport for modularity allows complex ontologies to be separated into smaller pieces (modules) that are easier to maintain and compute. Instead of considering the entire complex ontology, users may benefit more by starting from a problem-specific set of concepts (signature of problem) from the ontology and exploring its surrounding logical modules. Additionally, an ontology modularization mechanism allows for the splitting up of...
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Ancillary services to grids provided with distributed generation
PublicationThe paper introduces system for utilization of the customer-side generated energy. Additionally system can secure some ancillary services to grids. Those services include: current active filtering, load voltage stabilization and in case of grid voltage faults - uninterruptible load supplying (possible with energy storage device). Presented experimental results confirm flexibility of this arrangement in processes of power delivery...
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The effects of gas exposure on the graphene/AlGaN/GaN heterostructure under UV irradiation
PublicationThis work demonstrates a graphene/AlGaN/GaN sensing device with two-dimensional electron gas (2DEG) toward nitrogen dioxide (NO2), tetrahydrofuran, and acetone detection under UV light irradiation. We propose combining measurements of the DC characteristics with a fluctuation-enhanced sensing method to provide insight into the gas detection mechanisms in the synergistic structure of highly stable GaN and gas-sensitive graphene....
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New Architecture of Solid-State High-Voltage Pulse Generators
PublicationThe application of the nanosecond pulsed electric field (nsPEF) for biomedical treatments has gained more interest in recent decades due to the development of pulsed power technologies which provides the ability to control the electric field dose applied during tests. In this context, the proposed paper describes a new architecture of solid-state high-voltage pulse generators (SSHVPG) designed to generate fully customised sequences...
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Microwave Characterization of Dielectric Sheets in a Plano-Concave Fabry-Perot Open Resonator
PublicationDespite its long history, a double-concave (DC) Fabry-Perot open resonator (FPOR) has recently gained popularity in the characterization of dielectrics in the 20–110 GHz range, mainly due to such novel accomplishments as full automation of the measurement process and the development of even ore accurate and computationally efficient electromagnetic model. However, it has been discovered that such a DC resonator suffers from unwanted...
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Distributed System For Noise Threat Evaluation Based On Psychoacoustic Measurements
PublicationAn innovative system designed for the continuous monitoring of acoustic climate of urban areas was presentedin the paper. The assessment of environmental threats is performed using online data, acquired through a grid ofengineered monitoring stations collecting comprehensive information about the acoustic climate of urban areas.The grid of proposed devices provides valuable data for the purpose of long and short time acoustic climateanalysis....
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Design and Evaluation of the Compact and Autonomous Energy Subsystem of a Wave Energy Converter
PublicationThis paper presents the results of the design process focused on the development of the energy subsystem (ES) of a wave energy converter (WEC). The ES is an important electrical part that significantly affects the energy reliability and energy efficiency of the entire WEC device. The designed ES was intended for compact WECs powering IoT network devices working in the distributed grid. The developed ES is an electronic circuit...
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Optical method for verification of homogeneity of phantoms for calibration of magnetic resonance
PublicationThe primary purpose of this study was to develop a laboratory photonic set-up for characterisation of homogeneity of gel phantoms for calibration of magnetic resonance. In this system, optical coherence tomography allows the detection of micro- and macroscopic heterogeneities of a structure. The set-up was used to perform measurements of agar and agar-carrageenan gels, which are the basis for more complex phantoms for magnetic...
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Monoterpenes emissions from different samples of wood-based materials – laminated chipboards and medium-density fiberboards (MDF)
PublicationThe paper presents the results of studies on emission rates of monoterpenes, carried out with the use of a new type of device - Markes’ Micro-Chamber/Thermal Extractor™ (μ-CTE250). Subject of studies were different types of wood-based materials such as: laminated chipboards and medium-density fiberboards (MDF). Based on the results obtained one can conclude that the laminated chipboards may affect the indoor air quality in much...
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Determination of causes of accelerated local corrosion of austenitic steels in water supply systems
PublicationThis paper concerns an inspection of a water supply system, made of AISI 304 steel, which showed signs of local corrosion at the weld. Such corrosion caused material perforation after very short periods of operation. It was revealed that steel was sensitised during the welding process. It was also proven that chromium micro-segregation occurred in the alloy leading to galvanic cell formation which initialised the process of pitting...
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Obróbka cylindrów siłowników hydraulicznych przez roztaczanie z jednoczesnym nagniataniem
PublicationPrzedstawiono problematykę obróbki otworów w cylindrach hydraulicznych z użyciem specjalnych głowic rotaczająco nagniatających. Podano wyniki badań technologicznych obróbki cylindrów ze stali R45 głowicą dwunożową stosowaną podczas obróbki na tokarce specjalizowanej.Osiągnięto chropowatość powierzchni otworu w zakresie Ra = 0,16÷0,32 µm i klasę dokładności wymiarowej IT8. Podano również sposób adaptacji tokarki uniwersalnej...
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Coda wave interferometry in monitoring the fracture process of concrete beams under bending test
PublicationEarly detection of damage is necessary for the safe and reliable use of civil engineering structures made of concrete. Recently, the identification of micro-cracks in concrete has become an area of growing interest, especially using wave-based techniques. In this paper, a non-destructive testing approach for the characterization of the fracture process was presented. Experimental tests were made on concrete beams subjected to mechanical...
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Zastosowanie termowizji w diagnostyce i badaniach sprzętu elektronicznego
PublicationZaproponowano zastosowanie techniki termowizyjnej do oceny poprawność konstrukcji i działania urządzeń elektronicznych, biorąc pod uwagę krótki czas badań oraz możliwość bezpośredniej oceny uzyskanych wyników. Technikę termowizyjną zastosowano do badania elementów ochronnych zasilacza AC/DC w czasie standardowych badań odporności na udary oraz do badania modułów GSM pracujących pod kontrolą nadrzędnego programu sterującego i płyty...
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Zastosowanie termografii w diagnostyce i badaniach urządzeń elektronicznych
PublicationZaproponowano zastosowanie techniki termowizyjnej do oceny poprawność konstrukcji i działania urządzeń elektronicznych, biorąc pod uwagę krótki czas badań oraz możliwość bezpośredniej oceny uzyskanych wyników. Technikę termowizyjną zastosowano do badania elementów ochronnych zasilacza AC/DC w czasie standardowych badań odporności na udary oraz do badania modułów GSM pracujących pod kontrolą nadrzędnego programu sterującego i płyty...
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Impedance monitoring of corrosion degradation of plasma electrolytic oxidation coatings (PEO) on magnesium alloy
PublicationImpedance technique based on continuous multisinusoidal current perturbation was used to explain degradation process of plasma electrolytic oxidation coatings (PEO) on magnesium alloy. An obtained impedance spectrum was fitted by electrical equivalent circuit to describe properties of conversion layer on magnesium alloy. Additionally, galvanostatic mode maintained during experiment, with DC current equal to zero, allowed to achieve...
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Sterowanie rozdziałem energii w układach przekształtnikowych pojazdów elektrycznych i źródeł odnawialnych
PublicationW referacie omówiono wybrane zagadnienia sterowania rozdziałem energii zintegrowanych zasobników energii, zawierającychakumulatory i superkondensatory, stosowanych w układach przekształtnikowych małej mocy. Przedstawiono charakterystyki statycznewspółczynnika kd rozdziału energii zasobnika małego pojazdu elektrycznego zapewniającego minimalizacją strat energii w obwodzie DC oraz charakterystyki dynamiczne rozdziału energii w układach...
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Electrical mapping of AISI 304 stainless steel subjected to intergranular corrosion performed by means of AFM-LIS in the contact mode
PublicationThe paper presents results of the AFM-based approach to local impedance spectroscopy (LIS) measurements performed in a 20 20 lm grid within an austenite grain–grain boundary region for sensitized AISI 304 stainless steel (SS). Maps of electrical parameters obtained on the basis of localized impedance spectra were demonstrated, presenting their changes and correlation with the sample topography. Performed research revealed significant...
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Reducing Air Pollutant Emissions from the Residential Sector by Switching to Alternative Energy Sources in Single-Family Homes
PublicationThe paper discusses a scenario for adapting residential buildings to the requirements of the EU climate and energy package. It analyzes the option of reducing pollutant emissions to ambient air by switching to alternative energy sources in a typical single-family residential building. The most common sources of energy in central heating and ventilation systems and water heating systems were compared, and the analyzed energy carriers...
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Wind Conditions in Urban Layout – Numerical and Experimental Research
PublicationThis paper presents research which compares the numerical and the experimental results for different cases of airflow around a few urban layouts. The study is concerned mostly with the analysis of parameters, such as pressure and velocity fields, which are essential in the building industry. Numerical simulations have been performed by the commercial software Fluent, with the use of a few different turbulence models, including...
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Measurements and visualization of sound field distribution around organ pipe
PublicationMeasurements and visualization of acoustic field around an organ pipe are presented. Sound intensity technique was applied for this purpose. Measurements were performed in free field. The organ pipe was activated with a constant air flow, produced by an external compressor, aimed at obtaining long-term steady state responses of generated acoustic signal. Sound energy distribution was measured in a defined fixed grid of points...
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Acoustics - new services for urban planning, research and education
PublicationThe main purpose of the presented design is twofold, namely: providing detailed information about the noise threats that occur every day in city areas and preventing the noise induced hearing loss especially among young people. An experimental system designed for the continuous monitoring of the acoustic climate of urban areas was developed and implemented within the PLGrid Plus project. The assessment of environmental threats...
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Measurement and visualization of sound intensity vector distribution in proximity of acoustic diffusers
PublicationIn this work, we would like to present analyses and visualizations of sound intensity distribution measured in proximity of an acoustic diffuser. Such distribution may be used for estimation of basic acoustic parameters of a diffuser. Measurement is performed with the use of a logarithmic sine sweep which allows for the analysis of waves scattered by the diffuser and rejecting the direct sound signal component. Pressure and sound...
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Voltage Transients Transfer over Medium Voltage Instrument Transformers
PublicationThis paper presents voltage harmonic transfer accuracy problems through voltage transformers which are used in power quality monitoring systems in medium and high voltage grids. A simplified lumped parameters circuit model of the voltage transformer is proposed and verified by simulation and experimental investigations. A number voltage transformers typically used in medium voltage grid has been tested in the conducted disturbances...
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Application of wireless communication to small WECS with induction generator
PublicationWind energy conversion systems (WECS) seem to be self-evident elements of the future smart grids. Among many generator types the squirrel cage induction generator (SCIG) characterizes robustness and low cost. A full-scale power converter can perform smooth grid connection over wide speed range of multiple-stage geared SCIG. Increasing number of sensors can improve the WECS control and diagnostics but increasing number of thin wires...
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ZRÓŻNICOWANIE PŁYNNOŚCI FINANSOWEJ W ZALEŻNOŚCI OD WIELKOŚCI PRZEDSIĘBIORSTWA
PublicationW artykule przedstawiono różnice w sposobie kształtowania wartości wskaźników z obszaru płynności finansowej pomiędzy małymi, średnimi i dużymi przedsiębiorstwami. W trakcie przeprowadzonych badań uwzględniono 97 471 sprawozdań finansowych przedsiębiorstw, prowadzących działalność gospodarczą w 12 różnych działach polskiej gospodarki narodowej. Do potwierdzenia zróżnicowania płynności finansowej w zależności od wielkości przedsiębiorstwa...
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Zróżnicowanie zadłużenia w zależności od wielkości przedsiębiorstwa
PublicationW artykule przedstawiono różnice w sposobie kształtowania wartości wskaźników z obszaru zadłużenia pomiędzy małymi, średnimi i dużymi przedsiębiorstwami. W trakcie przeprowadzonych badań uwzględniono 97 471 sprawozdań finansowych przedsiębiorstw, prowadzących działalność gospodarczą w 12 różnych działach polskiej gospodarki narodowej. Do potwierdzenia zróżnicowania zadłużenia w zależności od wielkości przedsiębiorstwa wykorzystano...
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Proces zmiany sprzedawcy energii elektrycznej w Polsce dla odbiorcy w gospodarstwie domowym
PublicationW publikacji przedstawiono proces zmiany sprzedawcy energii elektrycznej dla odbiorcy w gospodarstwie domowym, prowadzony w detalicznym segmencie rynku energii. Szczególny nacisk położono na proces bazujący na generalnej umowie dystrybucji dla usługi kompleksowej. Odniesiono się do wszystkich, istotnych regulacji mających zastosowanie do poruszanych kwestii, ze szczególnym uwzględnieniem zapisów instrukcji ruchu i eksploatacji...
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Acceleration waves in the nonlinear micromorphic continuum
PublicationWithin the framework of the nonlinear elastic theory of micromorphic continua we derive the conditions for propagation of acceleration waves. An acceleration wave, also called a wave of weak discontinuity of order two, can be treated as a propagating nonmaterial surface across which the second derivatives of the placement vector and micro-distortion tensor may undergo jump discontinuities. Here we obtain the acoustic tensor for...
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Non-linear static stability of bi-layer carbon nanosheets resting on an elastic matrix under various types of in-plane shearing loads in thermo-elasticity using nonlocal continuum
PublicationIn this research, the shear and thermal buckling of bi-layer rectangular orthotropic carbon nanosheets embedded on an elastic matrix using the nonlocal elasticity theory and non-linear strains of Von-Karman was studied. The bi-layer carbon sheets were modeled as a double-layered plate, and van der Waals forces between layers were considered. The governing equations and boundary conditions were obtained using the first order shear...
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COMPARISION OF TWO WIND FARMS CONSTRUCTION PROJECTS USING F-AHP METHODP
PublicationReferat przedstawia porównanie projektów dwóch farm wiatrowych. Częścią referatu jest opis kryteriów, które muszą zostać uwzględnione w trakcie analizy porównawczej projektów budowy FW. Tego typu analiza znajduje zastosowanie w przypadku zakupu projektów inwestycyjnych będących w fazie przygotowania. Spowodowane jest to koniecznością uwzględnienia wymogów określonych w ustawodawstwie polskim...
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Measurement methods for assessing insulation condition of underground pipelines
PublicationThe paper discusses the most frequently applied measurement methods for assessing the quality of external insulation along pipelines and detecting defect locations in the protective coating. The quality of coating along a given pipeline section under investigation is assessed by determining unitary resistance of the coating, which is calculated on the basis of measurement results obtained along a pipeline subjected to cathodic...
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Symmetrical power line conditioner - basic properties
PublicationIn this paper the basis of analytical modelling of the UPQC arrangements (Unified Power Quality Conditioner) in d-q rotating coordinates, as well as select results of investigations conducted on the simplified small power laboratory model, were talked over. In short form power balance as well as fundamental dependences and analytical model with regard of decoupling circuits, were investigated. Applied method for DC link capacitance...
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Fabrication, structural and electrical properties of Sr(V,Nb)O 3-δ perovskite materials
PublicationThe SrV1-xNbxO3-δ materials with different niobium content in perovskite B-sublattice were prepared by a solid-state reaction process. The microstructure and phase compositions of obtained samples were analyzed by the X-ray diffraction technique (XRD) and scanning electron microscopy (SEM). The electrical conductivity of samples was measured by a DC 4-wire method in range of 100–600 °C in different gas conditions. The oxidation...
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Modeling and experimental investigation of the small UPQC systems
PublicationIn this paper the basis of analytical modelling of the UPQC arrangements (Unified Power Quality Conditioner) in d-q rotating coordinates, as well as select results of investigations conducted on the simplified small power laboratory model were talked over. In short form power balance as well as fundamental dependences and analytic model with regard of decoupling circuits were investigated. Applied method for DC link capacity selection...
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FEX a Fingers Extending eXoskeleton for Rehabilitation and Regaining Mobility
PublicationThis paper presents the design process of an exoskeleton for executing human fingers’ extension movement for the rehabilitation procedures and as an active orthosis purposes. The Fingers Extending eXoskeleton (FEX) is a serial, under-actuated mechanism capable of executing fingers’ extension. The proposed solution is easily adaptable to any finger length or position of the joints. FEX is based on the state-of-art FingerSpine serial...
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Imaging of Increasing Damage in Steel Plates Using Lamb Waves and Ultrasound Computed Tomography
PublicationThis paper concerns inspection of steel plates, with particular emphasis on the assessment of in-creasing damage. Non-destructive tests were performed on four plates, one of which was un-damaged, while the remaining three had a defects in the form of circular holes with a diameter of 2, 5, and 10 cm. Guided Lamb waves were used in the research, and the image reconstruction was performed using ultrasound computed tomography. The...
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Algorytmy wyodrębniania składowych symetrycznych sygnału pomiarowego napięcia w przypadku asymetrii sieci trójfazowej
PublicationW artykule zaprezentowano działanie wybranych algorytmów wykorzystywanych do wyodrębniania składowych symetrycznych z sygnałów pomiarowych napięcia lub prądu w przypadku wystąpienia asymetrii trójfazowej sieci elektroenergetycznej. Weryfikacji działania algorytmów dokonano na podstawie badań symulacyjnych i laboratoryjnych w układzie w którym jako odbiornik zastosowano stojan maszyny asynchronicznej pierścieniowej. Określono wpływ...
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Elementy analizy RAMS i cyklu życia napędów nowej generacji w układzie e-transformatora realizowanych w technologii SiC do elektrycznych zespołów trakcyjnych
PublicationTransport kolejowy podlega ciągłej presji, aby zwiększać dostępność połączeń i obniżać koszty przejazdów. Konstruktorzy pociągów i przewoźnicy, w odpowiedzi na stawiane oczekiwania, starają się wdrażać pojawiające się na rynku nowe innowacyjne rozwiązania. Europejski program Shift2Rail stawia ambitne cele w stosunku do kluczowych wskaźników wydajności (z ang. KPI - Key Performance Indicators) systemu kolejowego obejmującego infrastrukturę,...
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From Scores to Predictions in Multi-Label Classification: Neural Thresholding Strategies
PublicationIn this paper, we propose a novel approach for obtaining predictions from per-class scores to improve the accuracy of multi-label classification systems. In a multi-label classification task, the expected output is a set of predicted labels per each testing sample. Typically, these predictions are calculated by implicit or explicit thresholding of per-class real-valued scores: classes with scores exceeding a given threshold value...
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The system for identification of the band saw wheel cross profile
PublicationPrzedstawiono system do identyfikacji zarysu poprzecznego koła pilarki taśmowej, dzięki któremu producent pił taśmowych ma możliwość naprężenia brzeszczotu piły w sposób zapewniający jej poprawną pracę. Opisano budowę i zasadę działania systemu. Uzyskane dane mogą być wprowadzane do układów sterowania automatycznych urządzeń ze sterowaniem CNC (naprężających piły taśmowe). Dane systemu: szerokość sprawdzanych kół do 300 mm, dokładność...
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Komutacja prądu w gałęziach wybranych wyłączników hybrydowych.
PublicationW wyłącznikach hybrydowych funkcje przewodzenia prądu w stanach ustalonych i przejściowych łączeniowych przejmują kolejne gałęzie w biegunie łącznika. Opisano warunki komutacji prądu między gałęziami łącznika hybrydowego z przyrządem półprzewodnikowym (GTO i IGBT) z zestykiem z elektrodynamicznym napędem styku ruchomego i z beznapędowym łącznikiem topikowym. Czas komutacji prądu między gałęziami w obu typach łączników do chwili...
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Ionic Liquids and Deep Eutectic Mixtures: Sustainable Solvents for Extraction Processes
PublicationIn recent years, ionic liquids and deep eutectic mixtures have demonstrated great potential in extraction processes relevant to several scientific and technological activities. This review focuses on the applicability of these sustainable solvents in a variety of extraction techniques, including but not limited to liquid- and solid-phase (micro) extraction, microwave-assisted extraction, ultrasound-assisted extraction and pressurized...
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The use of Acoustic Emission to identification damages bearings the main and crank engines about the automatic ignition
PublicationThe article describes the laboratory tests, which make the first stage of the study concerning the use of the AE method to determine the technical state of the slide bearings in engines with self-ignition. The aim of the present tests was to compare the recorded signals in relation to the technical state of the material of the bearing bush and to check the possibility of using the AE method in determining the transition moment...
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Recovering Sound Produced by Wind Turbine Structures Employing Video Motion Magnification
PublicationThe recordings were made with a fast video camera and with a microphone. Using fast cameras allowed for observation of the micro vibrations of the object structure. Motion-magnified video recordings of wind turbines on a wind farm were made for the purpose of building a damage prediction system. An idea was to use video to recover sound & vibrations in order to obtain a contactless diagnostic method for wind turbines. The recovered signals...
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Factors Affecting the Rheological Properties of Foods
PublicationIn this chapter, engineering aspects concerning real body mechanics and the impact of respective food ingredients on said properties are presented together. Food is a complex matrix and each of macro and micro ingredients plays its role in the formation of rheologic properties, and minor changes in the basic ingredient structure may affect the change of these properties significantly. Basic analytic techniques are presented for...
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Position in global value chains and wages in Central and Eastern European countries
PublicationThis paper examines the relationship between the relative position of industries in Global Value Chains (GVC) and wages in 10 Central and Eastern European countries. We combine GVC measures of global import intensity of production, upstreamness and the length of the value chain with micro-data on workers. We find that the wages of Central and Eastern European countries workers are higher when their industry is at the beginning...
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Numerical investigations on early indicators of fracture in concrete at meso-scale.
PublicationFracture is a major reason of the global failure of concretes. The understanding of fracture is important to ensure the safety of structures and to optimize the material behaviour. In particular an early prediction possibility of fracture in concretes is of major importance. In this paper, concrete fracture under bending was numerically analysed using the Discrete Element Method (DEM). The real mesoscopic structure of a concrete...
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Superconducting properties and electronic structure of NaBi
PublicationResistivity, dc magnetization, and heat capacity measurements are reported for superconducting NaBi. Tc, the electronic contribution to the specific heat γ, the ΔCp/γTc ratio, and the Debye temperature are found to be 2.15 K, 3.4 mJ mol−1 K−2, 0.78, and 140 K respectively. The calculated electron–phonon coupling constant (λep = 0.62) implies that NaBi is a moderately coupled superconductor. The upper critical field and coherence...
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Development of an emulation platform for synchronous machine power generation system using a nonlinear functional level model
PublicationThe article presents the Power Hardware in the Loop (PHIL) approach for an autonomous power system analysis based on the synchronous generator model incorporating magnetic saturation effects. The model was prepared in the MATLAB/Simulink environment and then compiled into the C language for the PHIL platform implementation. The 150 kVA bidirectional DC/AC commercial-grade converter was used to emulate the synchronous generator....
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Dynamic variables limitation for backstepping control of induction machine and voltage source converter
PublicationDynamic variables limitation for backstepping control of induction machine and voltage source converter The paper presents the method of control of an induction squirrel-cage machine supplied by a voltage source converter. The presented idea is based on an innovative method of the voltage source converter control, consisting in direct joining of the motor control system with the voltage source rectifier control system. The combined...