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Search results for: truss towers
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Performance and Power-Aware Modeling of MPI Applications for Cluster Computing
PublicationThe paper presents modeling of performance and power consumption when running parallel applications on modern cluster-based systems. The model includes basic so-called blocks representing either computations or communication. The latter includes both point-to-point and collective communication. Real measurements were performed using MPI applications and routines run on three different clusters with both Infiniband and Gigabit Ethernet...
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An application of multi-agent system for ship’s power systems design
PublicationDesign process of transport ship power system consists of structure (topology) and component elements selection. Compliance with the requirements for static components does not guarantee optimal dynamic characteristics of entire power system. Design steps are difficult to formalize and as a consequence to this reason expert and multi-agent systems are used for solving selected design issues. In the paper distributed multi-agent...
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Distributed NVRAM Cache – Optimization and Evaluation with Power of Adjacency Matrix
PublicationIn this paper we build on our previously proposed MPI I/O NVRAM distributed cache for high performance computing. In each cluster node it incorporates NVRAMs which are used as an intermediate cache layer between an application and a file for fast read/write operations supported through wrappers of MPI I/O functions. In this paper we propose optimizations of the solution including handling of write requests with a synchronous mode,...
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Selected Problems of Transport in Port Towns – Tri-City as an Example
PublicationPort towns are strategic places from the point of view of transport systems. They form integration junctions for various transport branches , apart from the traditional - road and railway ones , also for water( sea) transport which is active there. Moreover, air transport comes also into consideration , whose efficient functioning must be connected with good accessibility, that concerns sea transport as well. Efficient and...
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Problems of Connecting Wind Farms to the Power System with HV Cables
PublicationThis paper presents problems caused by connecting wind farms to a power system with high voltage cables. The author highlights possible problems with reactive power compensation, depending on the arrangement of the shunt reactor connection and settings of control systems for reactive power and voltage of the wind farm. The paper also discusses issues of increasing active power losses caused by a shunt reactor installation.
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Power electronic transformer based on cascaded H-bridge converter
PublicationIn this paper the control strategy of power electronic transformer (PET) is proposed. The analyzed structure of PET uses two seven-level cascaded H-bridge (CHB) rectifiers. The electrical power of PET is transferred between DC-links of CHB converters using dual-active-bridges (DABs) and low voltage high frequency transformers. The roposed solution allows for controlling the active and reactive power with a low level of harmonic...
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Collaborative Delivery by Energy-Sharing Low-Power Mobile Robots
PublicationWe study two variants of delivery problems for mobile robots sharing energy. Each mobile robot can store at any given moment at most two units of energy, and whenever two robots are at the same location, they can transfer energy between each other, respecting the maximum capacity. The robots operate in a simple graph and initially each robot has two units of energy. A single edge traversal by an robot reduces its energy by one...
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LEGAL ASPECTS OF ELECTRIC ENERGY GENERATION IN A FLOATING POWER PLANT
PublicationThis paper discusses the characteristics of pollution and legal regulations governing investment projects affecting the environment. It describes a combined system of a compression ignition engine and a steam turbine, whose aim, when placed on a floating platform, is to produce electric energy in a so-called distributed generation system. Such a system involves a reciprocating internal combustion engine and a connected steam turbine...
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Cooperation of mono- and bi-articular muscles: human lower limb
PublicationObjectives: The aim of this study was to create and analyze a Pareto-optimal problem that would describe cooperation between mono- and bi-articulate lower limb muscles in sagittal plane. Methods: Equations describing the problem were derived and analyzed, additional constrains were introduced and experimental verification based on gait video analysis was performed. Results: Uncertainty of Pareto-optimal solution is shown for the...
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Diagnosis of bearing damage in induction motors by instantaneous power analysis
PublicationResearch of the machine with simulated bearing damages has been carried out, where variable load torque, simulating bearing damage, was introduced. The results show that components which can be used for bearings diagnosis appear in the spectrum of the product of current and supply voltage instantaneous values. These components are easier to identify than the components of current spectrum, which have been used so far in diagnostic...
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The Issues of Reactive Power Compensation in High-voltage Transmission Lines
PublicationThis paper discusses the selection of compensation shunt reactors for a double-circuit 400 kV transmission line using the example of the newly built Elk Bis – Alytus transmission line. The analysis takes into account various conditions of the power system. The published results relate to voltage levels in steady states and during switching processes and short circuits.
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Performance Evaluation of a 650V E-HEMT GaN Power Switch
PublicationGaN power switches have better characteristics compared to the state-of-the-art Si power transistors. These devices offer high operating temperature and current densities, fast switching and low on-resistance. However, currently only a few producers offer technology of high voltage GaN transistors. Immaturity of this technology is the reason why experimental evaluation of GaN parameters must be performed to properly exploit their...
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Compensation of Dead Time Effects for Shunt Active Power Filters
PublicationThe paper presents a comprehensive approach to the compensation of the grid current distortion for shunt active power filter systems. Four different sources of current distortion are addressed: imperfect grid synchronization caused by the distortion in the grid voltages, time delays in the estimation of compensating currents and grid voltages, fluctuations of the dc bus voltage, and the distortion of inverter output voltages due...
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Can Communication Power of Separable Correlations Exceed That of Entanglement Resource?
PublicationThe scenario of remote state preparation with a shared correlated quantum state and one bit of forward communication [B. Dakić et al., Nat. Phys. 8, 666 (2012)] is considered. Optimization of the transmission efficiency is extended to include general encoding and decoding strategies. The importance of the use of linear fidelity is recognized. It is shown that separable states cannot exceed the efficiency of entangled states by...
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Methods for evaluating rated power of diesel-powered generator set
PublicationBasic concepts for evaluating rated power of generator sets powered by combustion engines are presented in this article. A relation between parameters of the engine and the generator are shown. Recommendations contained in the standards and technical literature are systematized. The scheme and methodology for evaluating rated power of the generator set, based on laboratory research, are suggested. Also, the main problems which...
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Dedicated power supply subsystem for ultra-low noise preamplifiers
PublicationIn field of electronics there is need for low-noise amplifiers. Noise have the most important influence on analog circuits. Therefore exist necessity to develop new ultra-low noise power supplies, which can cooperate with specified amplifiers and preamplifiers. It is very common that professional power supplies are very expensive and still have disadvantages. This paper proposes simple and inexpensive solution, which fulfill specific...
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Dynamic state assessment of the water turbine with the power of 600 kW
PublicationThe article discusses the results of experimental studies to assess the dynamic state of the turbine set with the Kaplan turbine. The dynamic assessment was made on the basis of appropriate standards, based on the measurement results of selected parameters of vibration, which have been measured for several states of the machine load. In addition, we attempted to identify the causes of the increased vibration levels based on the...
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CAES – Energy storage providing stability for national power system
PublicationThis paper presents a short characteristics of the power system. It also describes various types of energy storage technologies. The suggested solution of accumulation and generation of electric power is based on the cooperation of gas turbine with Compressed Air Storage Energy systems – CAES. This analysis describes also various types of cooperation of CAES and renewable sources of energy, particularly wind power systems.
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Estimation of the Maximum Permissible PV Power to be Connected to the MV Grid
PublicationIn recent decades, a significant increase in the share of renewable energy sources in power grids at various voltage levels has been observed. A number of articles have been published highlighting emerging problems in low-voltage grids with a large share of prosumers and in medium- and high-voltage grids to which photovoltaic (PV) plants are connected. The article analyzes the medium-voltage grid in terms of the possibility of...
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Autoencoder application for anomaly detection in power consumption of lighting systems
PublicationDetecting energy consumption anomalies is a popular topic of industrial research, but there is a noticeable lack of research reported in the literature on energy consumption anomalies for road lighting systems. However, there is a need for such research because the lighting system, a key element of the Smart City concept, creates new monitoring opportunities and challenges. This paper examines algorithms based on the deep learning...
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Overcoming Phobias: Harnessing the Power of Immersive Virtual Reality Therapy
PublicationThe goal of the chapter was to review the different therapeutic techniques used in the treatment of various forms of phobias, with particular emphasis on virtual reality treatment. We define different types of phobias, including social ones. We also describe treatment techniques – adopted from behavioral therapy – which have been developed to aid the treatment of phobias. Particular emphasis has been placed on the flooding, implosive...
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Propagation Characteristics of Partial Discharges in an Oil-Filled Power Transformer
PublicationPower transformers are among the most important assets in the power transmission and distribution grid. However, they suffer from degradation and possible faults causing major electrical and financial losses. Partial discharges (PDs) are used to identify the insulation health status and their degradation level. PDs are incipient, low-magnitude faults caused by localized dielectric breakdown. Those activities emit signals in many...
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Solutions of inverter systems in Shore-to-Ship Power supply systems
PublicationThe article presents a clearly formulated need for installing S2SP (Shore to Ship Power) systems, in particular Medium Voltage (MV) systems, along with certain solutions of modern inverter systems used in those systems. Requirements and basic configurations of S2SP systems are discussed, focusing in particular on capabilities of the S2SP system with DC distribution busbar. Moreover, on the background of the executing assumptions...
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Design and evaluation of a base module of active power electronic transformer
PublicationThis paper presents an active power electronic transformer (APET) based on modular structure. The proposed three phase APET consists of at least three base modules (BM). The input/output stage of the BM is based on half-bridge sub modules. The isolation stage includes a medium frequency transformer and is realized as a dual half-bridge. The paper describes construction process and explains the control strategy. The theoretical...
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Pulse-Width Modulation of Power Electronic DC–AC Converter
PublicationThe Second Edition of High Performance Control of AC Drives with Matlab®/Simulink delivers an updated and thorough overview of topics central to the understanding of AC motor drive systems. The book includes new material on medium voltage drives, covering state-of-the-art technologies and challenges in the industrial drive system, as well as their components, and control, current source inverter-based drives, PWM techniques for...
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Compact and Integrated High-Power Pulse Generation and Forming System
PublicationThis paper presents comprehensive analytical, numerical and experimental research of the compact and integrated high-power pulse generation and forming system based on the flux compression generator and the electro-explosive forming fuse. The paper includes the analysis of the presented solution, starting from the individual components studies, i.e., the separate flux compression generator tests in field conditions and the forming...
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Preliminary study on icebreaking operation on the Middle and Lower Odra River
PublicationThe Odra-Vistula Flood Management Project (OVFMP) is implemented with the assistance of international financial institutions, including the International Bank for Reconstruction and Development and the Council of Europe Development Bank, as well as with the support of funding from the Cohesion Fund and the state budget. Aside from others, the objective of the OVFMP is to increase flood protection for people living in selected areas...
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THE INFLUENCE OF PHASE SHIFTERS ON THE VOLTAGE STABILITY OF CONNECTED POWER SYSTEMS
PublicationThe paper presents the results of simulation tests of connected power systems in which phase shifters were installed on cross-border links. The analysis was carried out in terms of assessing the impact of shifters on node voltage stability. Individual systems were characterized by different balance of active power: deficit or excess. The evaluation of voltage stability was based on the dU/dQ and dU/dP criteria.
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Optimizing CO2 Purification in a Negative CO2 Emission Power Plant
PublicationIn the pursuit of mitigating CO2 emissions, this study investigates the optimisation of CO2 purification within a Negative CO2 Emission Power Plant using a spray ejector condenser (SEC) coupled with a separator. The approach involves direct-contact condensation of vapour, primarily composed of an inert gas (CO2), facilitated by a subcooled liquid spray. A comprehensive analysis is presented, employing a numerical model to simulate...
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The effect of temperature on the power drop in crystalline silicon solar cells
PublicationPrzedstawiono wpływ temperatury i długości fali zaabsorbowanego promieniowania na parametry elektryczne krzemowych ogniw i modułów fotowoltaicznych. Zaobserwowano spadek mocy wyjściowej (-0.65%/K), współczynnika wypełnienia charakterystyki FF (-0.2%/K) i sprawności konwersji (-0.08%/K) ze wzrostem temperatury. Zaprezentowano również charakterystykę spektralną napięcia otwartego obwodu dla ogniw krzemowych.
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On the power systems performance control starting from disturbances measurements
PublicationReferat przedstawia badanie działania układu sterowania w systemie elektroenergetycznym oparte na oszacowanie parametrów. Na podstawie pomiarów wykonanych w stanie zakłóconiowym, parametry te są oszacowane minimizując uchyb pomiędzy wartościami wielkości uzyskanych z pomiarów i wartościami wielkości wyjściowych modelu systemu elektroenergetycznego. W celu zmniejszenia tego uchybu, proponowano dwie metody: klasyczna oparta na czułości...
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The idea of a geothermal power station working in national geological conditions.
PublicationPrzedstawiono koncepcję elektrowni geotermalnej pracującej w krajowych warunkach geologicznych. Przeprowadzono analizę obiegu Clausiusa-Rankine'a i na tej podstawie dobrano parametry obiegu na czynnik niskowrzący - izobutan. Określono główne wymiary urządzeń do realizacji technicznej takiej elektrowni. Przeprowadzono uproszczoną analizę ekonomiczną takiej inwestycji.
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Hardware-in-the-Loop Simutation of the Synchronization Process of Electric Power Units.
PublicationPrzedstawiono nowoczesne urządzenia do badań synchronizatorów automatycznych w warunkach laboratoryjnych. Szczególną uwagę poświęcono systemowi wizualizacji tych urządzeń )przy ich pomocymożliwa jest ciągła kontrola, sterowanie i wizualizacja procesem synchronizacji w systemie elektroenergetycznym.
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Multimachine power system stability improvement using fuzzy control.
PublicationW celu poprawienia stabilności dynamicznej turbogeneratora i powiększenia tłumienia kołysań elektromechanicznych opracowano regulator napięcia wraz z stabilizatorem systemowym z wykorzystaniem teorię zbiorów rozmytych. Efektywność opracowanego rozmytego algorytmu oceniono w układzie wielomaszynowym.
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Hydraylic turbine development vor lov-output power plants.
PublicationPraca zawiera wyniki badań nowego układu przepływowego turbiny wodnej, na tle krytyki stosowanych powszechnie technologii w hydroenergetyce. Pokazano efekty energetyczne pracy turbiny i kształt kinematyki przepływu w jej kanałach hydraulicznych. Pokazano również skutki stosowania metody optymalizacyjnej dla osiągania wyższych sprawności pracy wirnika turbiny.
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Small hydro-power as a source of renewable energy in the European Union
PublicationW pracy przedstawiono udział odnawialnych źródeł energii w produkcji energii elektrycznej w 25 krajach Unii Europejskiej w roku 1997 i przewidywanu udział w roku 2010. Omówiono krótką historię rozwoju małych elektrownii wodnych w UE i dokonano przeglądu małych elektrowni wodnych w krajach UE oraz w wybranych krajach Europy, nie należących do UE. Przedstawiono także możliwy rozwój małej energetyki wodnej w okresie perspektywicznym...
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Effect of hybrid contactless short-cicruit limiters on power quality
PublicationPrzedstawiono działanie bezstykowego ogranicznika prądów zwarciowych w oparciu o symulację komputerową. Szczególną uwagę zwrócono na problem jakości dostarczanej energii elektrycznej poprzez ograniczanie zapadów napięcia za pomocą bezstykowego ogranicznika prądów zwarciowych. W modelowaniu elementów systemu elektroenergetycznego i zapadów napięcia, będących skutkiem zwarć wykorzystano program MATLAB z biblioteką Power System Blockset....
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Potential reduction of traffic noise by the means of increased fleet of electric vehicles using a combination of low-noise tyres and low-noise road surfaces
PublicationIn the future, the number of zero-emission vehicles like electric and plug-in hybrid vehicles (in electric mode) is expected to be a substantial part of the vehicle fleet. In Norway, such vehicles already account for approximately 20 % of all new cars sold. Since these vehicles emit negligible noise related to the power-train, the tyre/road noise is the dominating noise source. In the LEO project, tyres designed for such cars have...
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Tyre/road noise measurements on ISO tracks according to the UNECE Regulation 117
PublicationWithin the Polish-Norwegian research project ELANORE, a limited Round Robin Test has been performed on 3 ISO tracks in Northern Europe. The basic objective of the project is to improve the EU directive on labelling of tyres for noise and rolling resistance, and this directive is based on the measurement procedures defined in the UN ECE Reg.117. The same test car, test tyres and measurement equipment as well as personnel were used...
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Representativity of ISO test track surface based on controlled pass-by measurements
PublicationWithin the Polish-Norwegian research project ELANORE, a limited Round Robin Test has been performed on four ISO tracks in Northern Europe. The basic objective of the project is to improve the EU directive on labelling of tyres for noise and rolling resistance. This directive is based on the measurement procedures proscribed in the UNECE Reg.117. Measurements on 3 ISO tracks were performed in 2021 and presented at InterNoise 2022....
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Tyre/road noise measurements on ISO tracks using the modified CPX method
PublicationTyre rolling noise test method specified in the UNECE Regulation 117 is directly used in the Tyre Labelling Directive. Noise level specified on EU Tyre Label of each new tyre available on the European market was determined based on vehicle coast-by noise measurements performed on the standard reference road surface proscribed in the ISO 10844:2014. Available data from investigations by the vehicle and tyre industry and results...
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Zaufanie do siebie jako jeden z aspektów zaufania w aktywności przedsiębiorczej
PublicationArtykuł prezentuje znaczenie zaufania do samego siebie na tle zaufania w relacjach budowanych przez przedsiębiorcę w jego otoczeniu społecznym i biznesowym. Wyjaśniono koncepcję zaufania do samego siebie, odnosząc się do zróżnicowanych typów zaufania, na przykład: kalkulacyjnego, opartego na wiedzy i identyfikacyjnego. Wskazano jego potencjalne źródła i konsekwencje w kontekście budowania własnego wizerunku, podejmowania decyzji...
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Discrete random variables in reliability calculations of a reticulated shell
PublicationImplementation of the Point Estimation Method (PEM) in the reliability analysis of a three-dimensional truss structure is presented in the paper. The influence of geometric and material random parameters on the truss load-carrying capacity was investigated. The analysis was performed for different combinations of basic variables. Symmetric and asymmetric cases of snow load were taken to assess the structural reliability. Sensitivity...
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Attitudes of Polish physicians, nurses and pharmacists towards the ethical and legal aspects of the conscience clause
PublicationBackground: While healthcare professionals’ right to invoke the conscience clause has been recognised as a fundamental human right, it continues to provoke a heated debate in Polish society. Although public discourse is filled with ethical and legal considerations on the conscience clause, much less is known about the attitudes of healthcare professionals regarding that matter. The aim of this study was therefore...
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Ornamental Flowers Grown in Human Surroundings as a Source of Anthocyanins with High Anti-Inflammatory Properties
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Physicochemical properties of whole fruit plum powders obtained using different drying technologies
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Chemical Composition and Antioxidant Properties of Powders Obtained from Different Plum Juice Formulations
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Functional relationships between phytochemicals and drying conditions during the processing of blackcurrant pomace into powders
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Effect of thienyl units in cyanoacrylic acid derivatives toward dye-sensitized solar cells
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Hypertension and cardiovascular disease in women: Progress towards better understanding of gender‐specific differences?
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