Search results for: power stations interconnection with distribution grid
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Cleaner energy for sustainable future using hybrid photovoltaics-thermoelectric generators system under non-static conditions using machine learning based control technique
PublicationIn addition to the load demand, the temperature difference between the hot and cold sides of the thermoelectric generator (TEG) module determines the output power for thermoelectric generator systems. Maximum power point tracking (MPPT) control is needed to track the optimal global power point as operating conditions change. The growing use of electricity and the decline in the use of fossil fuels have sparked interest in photovoltaic-TEG...
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Stabalization of solar-panel energy system for Pakistani household
PublicationRenewable energy resources such as Sun and wind are getting popular and easier to use day by day. It is a better method to fulfill our demands as sun is a continuous source of energy for Earth. Many countries are fulfilling their demands by Solar Panels. Solar panel is used as a converter between sunlight and electrical energy. This research paper is going to tell that how to obtain electrical energy from sunlight more efficiently...
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The Conceptual Research over Low-Switching Modulation Strategy for Matrix Converters with the Coupled Reactors
PublicationIn this paper, different Pulse Width Modulation (PWM) strategies for operating with a low-switching frequency, a topology that combines Conventional Matrix Converters (CMCs), and Coupled Reactors (CRs) are presented and discussed. The principles of the proposed strategies are first discussed by a conceptual analysis and later validated by simulation. The paper shows how the combination of CMCs and CRs could be of special interest...
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PROJEKTOWANIE STANOWISK LABORATORYJNYCH WSPIERAJĄCYCH PROCES SZKOLENIA PRAKTYCZNEGO KADR MORSKICH DZIAŁU MASZYNOWEGO W ŻEGLUDZE MIĘDZYNARODOWEJ, PRZYBRZEŻNEJ I KRAJOWEJ
PublicationWithin the article a design offer of the Department of Ship and Power Plants of the Faculty of Ocean Engineering And Ship Technology at the Gdansk University of Technology has been presented. The offer concerns designing laboratory stations which might stand for the equipment of a didactic base of maritime educational centers i.e. maritime (naval) academies and schools as well as maritime affairs' professional training centers,...
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Conception and design of a hybrid exciter for brushless synchronous generator. Application for autonomous electrical power systems = Koncepcja i projekt hybrydowej wzbudnicy bezszczotkowego generatora synchronicznego. Zastosowanie w autonomicznych systemach elektroenergetycznych.
PublicationThis paper covers a subject of a hybrid excitation system for a brushless synchronous generator working with variable speed in an autonomous energy generation system (e.g. airplane power grid). A hybrid excitation system (hybrid exciter) means a synchronous machine with wound-field and permanent magnet excitation. The hybrid exciter supply a dc field current to the synchronous generator field winding through a rotating rectifier....
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A method of nonlinearities of transformer no-load characteristic modelling
PublicationA way in which changes of the no-load characteristic are taken into account in the mathematical model of the transformer is presented. Changes of saturation within core of transformer are presented as a combined non-linear flux curve. Analysis of magnetization of the transformer core and simulation of no-load state for distribution transformer of 30 kVA power rating and 15.75/0.4 kV/kV (especially supplying VLV) transformation...
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Shady S. Refaat
PeopleShady S. Refaat received the B.A.Sc, M.A.Sc., and Ph.D. degrees in Electrical Engineering in 2002, 2007, and 2013, respectively, all from Cairo University, Giza, Egypt. He has worked in the industry for more than 12 years as Engineering Team Leader, Senior Electrical Engineer, and Electrical Design Engineer on various electrical engineering projects. He has worked as an associate research scientist in the Department of Electrical...
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Feasibility Study of Three-Phase Modular Converter for Dual-Purpose Application in DC and AC Microgrids
PublicationThe modern concept of a universal converter is intended as a power converter suitable for application in both dc or ac grids using the same external connectors. This novel family was recently proposed to allow an easier integration of renewable energy sources and energy storage systems, interfacing with dc/ac grids and/or loads with a minimum redundancy of power switches and passive elements. This kind of solution and applications...
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Solar Photovoltaic Energy Optimization and Challenges
PublicationThe study paper focuses on solar energy optimization approaches, as well as the obstacles and concerns that come with them. This study discusses the most current advancements in solar power generation devices in order to provide a reference for decision-makers in the field of solar plant construction throughout the world. These technologies are divided into three groups: photovoltaic, thermal, and hybrid (thermal/photovoltaic)....
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Frequency Diagnostics of Transformer Insulating Parameters
PublicationIn the article is presented experimental analysis and diagnostics of insulating system oil-paper for power transformers, mainly by progressive frequency method – dielectric spectroscopy. In the 1-st part of the article is described base theory about measurement and diagnostics insulating part (oil and paper) of power transformers. In the 2-nd part of article is described measuring method of insulating frequency diagnostics - frequency...
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Organic Rankine cycle as bottoming cycle to a combined Brayton and Clausius - Rankine cycle
PublicationA preliminary evaluation has been made of a possibility of bottoming of a conventional Brayton cycle cooperating with the CHP power plant with the organic Rankine cycle installation. Such solution contributes to the possibility of annual operation of that power plant, except of operation only in periods when there is a demand for the heat. Additional benefit would be the fact that an optimized backpressure steam cycle has the advantage...
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Identification of the Contamination Source Location in the Drinking Water Distribution System Based on the Neural Network Classifier
PublicationThe contamination ingression to the Water Distribution System (WDS) may have a major impact on the drinking water consumers health. In the case of the WDS contamination the data from the water quality sensors may be efficiently used for the appropriate disaster management. In this paper the methodology based on the Learning Vector Quantization (LVQ) neural network classifier for the identification of the contamination source location...
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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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FEM modelling of stress and strain distribution in weld joints of steel sandwich panels
PublicationThe development of laser welding technology has enabled the mass production of thin-walled structures, including steel sandwich panels. The technology of joining plating panels with stiffeners by welding allows us to create joints with a specific geometry and material properties. In comparison with other types of joints, laser welds are characterized by their specific behaviour under cyclic load and, as a consequence, a different...
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The Boltzmann sequence-structure channel
PublicationWe rigorously study a channel that maps binary sequences to self-avoiding walks in the two-dimensional grid, inspired by a model of protein statistics. This channel, which we also call the Boltzmann sequence-structure channel, is characterized by a Boltzmann/Gibbs distribution with a free parameter corresponding to temperature. In our previous work, we verified experimentally that the channel capacity has a phase transition for...
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Modified Preisach model of hysteresis in multi air gap ferrite core medium frequency transformer
PublicationThis article presents the modified Preisach model of hysteresis for a 3-phase medium frequency transformer in a 100 kW dual active bridge converter. The transformer magnetic core is assembled out of ferrite I-cores, which results in multiple parasitic air gaps. For this transformer, the hysteresis loops were measured and parameters of the Preisach model were determined. The Preisach distribution function is approximated with a...
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Simulating Power Generation from Photovoltaics in the Polish Power System Based on Ground Meteorological Measurements—First Tests Based on Transmission System Operator Data
PublicationThe Polish power system is undergoing a slow process of transformation from coal to one that is renewables dominated. Although coal will remain a fundamental fuel in the coming years, the recent upsurge in installed capacity of photovoltaic (PV) systems should draw significant attention. Owning to the fact that the Polish Transmission System Operator recently published the PV hourly generation time series in this article, we aim...
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Solar Photovoltaic Energy Optimization and Challenges
PublicationThe study paper focuses on solar energy optimization approaches, as well as the obstacles and concerns that come with them. This study discusses the most current advancements in solar power generation devices in order to provide a reference for decision-makers in the field of solar plant construction throughout the world. These technologies are divided into three groups: photovoltaic, thermal, and hybrid (thermal/photovoltaic)....
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Experiment-Based Study of Heat Dissipation from the Power Cable in a Casing Pipe
PublicationThe paper deals with the important challenges in terms of electricity transmission by means of underground cable lines. The power cable’s performance is characterized by an ampacity that represents its maximum electric current-carrying capacity. The ampacity of power cables depends on their ability to diffuse the heat generated by the current flow into the environment. In the performed research, the analysis of the efficiency of...
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LabVIEW-based intelligent system of protection against electric shock for photovoltaic installations
PublicationEvaluation of shock hazard in installations with photovoltaic sources of energy is more complicated than in a conventional low voltage system. In case of earth fault in photovoltaic generators, that are connected to the AC power public grid, a composite waveform of earth fault current in the installation may occur. For composite waveforms, the safety criteria should be modified. The paper considers the effect of the composite waveforms...
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Przegląd systemów ładowania elektrycznych osobowych pojazdów i koncepcja dwukierunkowej ładowarki pokładowej
PublicationAktualnie trwa intensywny rozwój pojazdów elektrycznych (EV) i hybrydowych typu plug-in (PHEV) z pokładowymi bateriami akumulatorów. Badania w tej dziedzinie skupiają się na maksymalizowaniu sprawności oraz minimalizowaniu masy i objętości systemów ładowania baterii. W artykule przedstawiono podział systemów ładowania osobowych pojazdów typu EV/PHEV. Opisano systemy ładowania przewodowego z podziałem na ładowarki pokładowe i zewnętrzne, systemy...
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Exergy analysis of a negative CO2 emission gas power plant based on water oxy-combustion of syngas from sewage sludge gasification and CCS
PublicationA power cycle with water-injected oxy-combustion (water cycle) is investigated by exergy analysis. It is fueled with syngas (aka. producer gas) from gasification of sewage sludge. The cycle is equipped with a spray-ejector condenser (SEC). CO2 is separated and compressed for transportation and storage. The net delivered electric power is 31% of the fuel exergy. The task efficiency is 39% when the flue gas bleed to gasification...
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Feasibility Study of Three-Phase Modular Converter for Dual-Purpose Application in DC and AC Microgrids
PublicationThe modern concept of a universal converter is intended as a power converter (PC) suitable for application in both dc or ac grids using the same external connectors. This novel family was recently proposed to allow easier integration of renewable energy sources and energy storage systems (ESSs), interfacing with dc/ac grids and/or loads with a minimum redundancy of power switches and passive elements. This kind of solution and...
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The Influence of External Load on the Performance of Microbial Fuel Cells
PublicationIn this work, the effect of the external load on the current and power generation, as well as on the pollutant removal by microbial fuel cells (MFCs), has been studied by step-wise modifying the external load. The load changes included a direct scan, in which the external resistance was increased from 120 Ω to 3300 Ω, and a subsequent reverse scan, in which the external resistance was decreased back to 120 Ω. The reduction in the...
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Experimental Study of the Influence of Noise Level on the Uncertainty Value in a Measurement System Containing an Analog-to-Digital Converter
Open Research DataFor newly developed measuring systems it is easy to estimate type B uncertainties based on the technical data of the measuring modules applied. However, it is difficult to estimate A type un-certainties due to the unknown type and level of interferences infiltrating into the measuring sys-tem. This is a particularly important problem for measurements...
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Feedback Control of Doubly-Fed Generator Connected to Current Source Converter
PublicationDoubly-fed induction generator (DFIG) system supplied by current source converter (CSC) is considered in this article. The DFIG can work in two independent modes: AC grid connection and stand-alone mode. The DFIG is connected to the ac grid directly through its stator and the CSC links the rotor side. In this mode, the active and reactive powers of the DFIG must be controlled. This article proposes two control system structures...
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Modelling of the High Speed Multi-Pole Synchronous Generator for Application in More Electric Aircraft Power Systems
PublicationIn this paper different models of the synchronous generator are presented. The simulation results compared with the measurements are shown. Certain physical phenomena are included in described models for the porpoise of adequate analysis of the more electric aircraft power system. For different modelling levels, such as functional level or behavioural level, different physical phenomena have been included. Simulation results for...
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SZACOWANIE ZAWARTOŚCI BENZO(a)PIRENU W PYLE ZAWIESZONYM PM10 W AGLOMERACJI TRÓJMIEJSKIEJ ZA POMOCĄ WIELOWYMIAROWEJ REGRESJI LINIOWEJ=ESTIMATION OF BENZO(A)PYRENE CONTENT IN SUSPENDED DUST PM10 IN TRI-CITY AGGLOMERATION USING MULTIDIMENSIONAL LINEAR REGRESSION
PublicationW pracy przedstawiono próbę oszacowania przy pomocy wielowymiarowej regresji liniowej modelu empirycznego opisującego czynniki wpływające na zawartość B(a)P w pyle zawieszonym PM10 w Aglomeracji Trójmiejskiej w latach 2008-2011. Na przestrzeni tych lat średnioroczne stężenie B(a)P w PM10 wzrosło ponad dwukrotnie i ponad trzykrotnie przewyższa poziom docelowy. Z przeprowadzonych analiz wynika, że główną przyczyną wzrostu stężenia...
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Damage Detection Strategies in Structural Health Monitoring of Overhead Power Transmission System
PublicationOverhead power transmission lines, their supporting towers, insulators and other elements create a highly distributed system that is vulnerable to damage. Typical damage scenarios cover cracking of foundation, breakage of insulators, loosening of rivets, as well as cracking and breakage of lines. Such scenarios may result from various factors: groundings, lightning strikes, floods, earthquakes, aeolian vibrations, conductors galloping,...
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ANALYSIS OF EFFECTIVENESS AND COMPUTATIONAL COMPLEXITY OF TREND REMOVAL METHODS
PublicationThe paper presents a method of processing measurement data due to remove slowly varying component of the trend occurring in the recorded waveforms. Comparison of computational complexity and trend removal efficiency between some commonly used methods is presented. The impact of these procedures on probability distribution and power spectral density is shown. Effectiveness and computational complexity of these methods depend essentially...
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Energy neutrality versus carbon footprint minimization in municipal wastewater treatment plants
PublicationThis work aimed to compare the carbon footprint (CF) of six full-scale wastewater treatment plants (WWTPs). The CF was estimated in the range of 23–100 kg CO2e per population equivalent. In the total CF, the direct emissions held the highest share (62–74%) for the plants with energy recovery from biogas. In the plants depending entirely on the power grid, the indirect emissions due to energy consumption dominated the total CF (69–72%)....
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Potential Application of Solar Energy Systems for Electrified Urban Transportation Systems
PublicationThe paper presents a novel approach toward the use of solar energy systems in public transportation. The concept of energy generation in PV systems for supplying a trolleybus transportation system is proposed for the city of Gdynia (Poland). The suggested way of energy production allows reducing the environmental harm impact of the municipal transportation system. Moreover, the proposed way of green energy use can be a more profitable...
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Multi-objective optimization of the ORC axial turbine for a waste heat recovery system working in two modes: cogeneration and condensation
PublicationDue to the demand of the district heating network and electric power grid ORC turbines can operate in the condensation and cogeneration modes. This approach requires the design of an expander which is characterized by high efficiency in each mode of operation. The paper is devoted to a multi-objective efficiency optimization of a one stage axial ORC turbine working on MM (Hexamethyldisiloxane). An Implicit Filtering algorithm (IF)...
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Medium-Voltage Drives: Challenges and existing technology
PublicationThe article presents an overview of state-of-art solutions, advances, and design and research trends in medium-voltage (MV) drive technologies - and also discusses the challenges and requirements associated with the use of such drives. The choice and deployment of MV drives in industries are associated with numerous requirements related to the front-end converter (grid side) and inverter (machine side). The focus is on solutions...
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Monitoring of breast tissue thermo-ablation by means of impedance measurements
PublicationW pracy przedstawiono rozważania dotyczące monitorowania jakości termoablacji zmian nowotworowych w piersi przy pomocy pomiarów impedancyjnych. Pokazano prototypowe konstrukcje sond do termoablacji jak również zaprezentowano wyniki symulacji i pierwszych eksperymentów. A usefulness of a developed probe combining power delivery to ablated breast tumour and simultaneous impedance measurements is discussed in the paper. It consists...
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Computer-Aided Calculations of Earth Potential Rise in High Voltage Overhead Lines
PublicationHigh voltage overhead power lines with earth wires comprise towers made of conductive material. Some towers are in locations where people can be expected to be either for a long time or for a short time but very frequently. Evaluation of shock hazard near such towers requires calculation of line-to-earth short-circuit current, earth current and especially earth potential rise. Number of towers in high voltage power lines can exceed...
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Silicon Oxycarbide-Graphite Electrodes for High-Power Energy Storage Devices
PublicationHerein we present a study on polymer-derived silicon oxycarbide (SiOC)/graphite composites for a potential application as an electrode in high power energy storage devices, such as Lithium-Ion Capacitor (LIC). The composites were processed using high power ultrasound-assisted sol-gel synthesis followed by pyrolysis. The intensive sonication enhances gelation and drying process, improving the homogenous distribution of the graphitic...
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Nonlinear Control of a Doubly Fed Generator Supplied by a Current Source Inverter
PublicationNowadays, wind turbines based on a doubly fed induction generator (DFIG) are a commonly used solution in the wind industry. The standard converter topology used in these systems is the voltage source inverter (VSI). The use of reverse-blocking insulated gate bipolar transistor (RB-IGBT) in the current source inverter topology (CSI), which is an alternative topology, opens new possibilities of control methods. This paper presents...
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Pomiar odpowiedzi impulsowej kanału radiowego na obszarze morskim i przybrzeżnym
PublicationW artykule zaprezentowano wyniki pomiarów odpowiedzi impulsowej kanału radiowego na obszarze morskim i przybrzeżnym. Pomiary przeprowadzono na częstotliwości 1457 MHz a sygnałem sondującym był sygnał o paśmie 10 MHz z modulacją BPSK i pseudoprzypadkową zawartością binarną. Odbierane sygnały były rejestrowane przez dwie stacje ruchome, zainstalowane w samolocie i na łodzi patrolowej. Podczas późniejszej obróbki danych zastosowano...
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Design analysis of Tesla micro-turbine operating on a low-boiling medium
PublicationThis paper presents results of the design analysis of a Tesla bladeless turbine intended for a co-generating micro-power plantof heat capacity 20 kW, which operates in an organic Rankine cycle on a low-boiling medium. Numerical calculations of flowin several Tesla turbine models were performed for a range of design parameters. Results of investigations exhibit interestingfeatures in the distribution of flow parameters within the...
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"Creating a numerical model of noise conditions based on the analysis of traffic volume changes in cities with low and medium structure.
PublicationThe subject of this research study is to analyze noise conditions of the selected area in the city of Gdańsk using data related to traffic volume changes during a day. This is because daily distribution of noise levels is much more helpful for noise control and reduction than traditional maps with Lden levels indicated. Calculations are made with the use of a numerical model developed at the Gdansk Univ. of Technology and implemented...
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"Creating a numerical model of noise conditions based on the analysis of traffic volume changes in cities with low and medium structure.
PublicationThe subject of this research study is to analyze noise conditions of the selected area in the city of Gdańsk using data related to traffic volume changes during a day. This is because daily distribution of noise levels is much more helpful for noise control and reduction than traditional maps with Lden levels indicated. Calculations are made with the use of a numerical model developed at the Gdansk Univ. of Technology and implemented...
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Human verbal memory encoding is hierarchically distributed in a continuous processing stream
PublicationProcessing of memory is supported by coordinated activity in a network of sensory, association, and motor brain regions. It remains a major challenge to determine where memory is encoded for later retrieval. Here we used direct intracranial brain recordings from epilepsy patients performing free recall tasks to determine the temporal pattern and anatomical distribution of verbal memory encoding across the entire human cortex. High...
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On the Origin of Protein Superfamilies and Superfolds
PublicationDistributions of protein families and folds in genomes are highly skewed, having a small number of prevalent superfamiles/superfolds and a large number of families/folds of a small size. Why are the distributions of protein families and folds skewed? Why are there only a limited number of protein families? Here, we employ an information theoretic approach to investigate the protein sequence-structure relationship that leads to...
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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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Asymmetrical Modes in Polyphase Motors and Drives
PublicationThe effect of power supply and/or motor asymmetry on the phase-load distribution and the ripple of electromagnetic torque in a polyphase drive is studied by the method of symmetrical components. It is shown that the presence of asymmetry causes the mapping of all harmonics in the supply voltage into all planes of symmetrical components and eliminates the possibility of independent control of harmonics. The dynamic model of a five-phase...
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Minichannel and minigap classification criteria based on the aspect ratio of the minigeometry: A numerical study
PublicationA detailed numerical investigation has been carried out to analyze the diabatic flow distribution and velocity profile in 18 minigeometries with various aspect ratios for V-type and I-type flow configurations (for 36 cases) assuming ethanol as a working fluid. The aim of the study is to distinguish the value of the aspect ratio for which the flow in minigeometry starts to be two-dimensional (minigap). Cases with a constant Reynolds...
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Innovative system for energy collection and management integrated within a photovoltaic module
PublicationThe dynamic development of battery technology and design based on the flow of lithium ions, mainly driven by the needs of the automotive industry, leads to the conclusion that these batteries are becoming a more viable alternative to traditional lead-acid batteries. Their use is driven by the ability to quickly charge and discharge, a higher durability, maintenance-free operation, much smaller dimensions and lighter weight. The...
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Conditions for increasing the recognition of degradation in thermal-flow diagnostics, taking into account environmental legal aspects
PublicationThe ever-increasing demand for electricity and the need for conventional sources to cooperate with renewable ones generates the need to increase the efficiency and safety of the generation sources. Therefore, it is necessary to find a way to operate existing facilities more efficiently with full detection of emerging faults. These are the requirements of Polish, European and International law, which demands that energy facilities...
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Composite Materials Based on Silicon Oxycarbide as Anodes for Lithium-Ion Batteries
PublicationIn this work, the properties of binary SiOC/graphite and SiOC/tin, as well as ternary SiOC/graphite/tin obtained from various preceramic precursors are described. During the first step, the materials were synthesized using various techniques such as sol-gel and hydrosilylation. To prevent sedimentation and agglomeration of graphite particles during the gelation stage without using surfactants and thickeners, a new gelation technique...