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Search results for: GALLIUM NITRIDE SOURCED SWITCHED FET (GAN SSFET)
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The PWM current source inverter with IGBT transistors and multiscalar model control system
PublicationW niniejszym artykule przedstawiono struktury układów sterowania maszyny indukcyjnej zasilanej z falownika prądu. Przedstawiono metodę modulacji szerokości impulsów dla falownika prądu. Pokazano modele matematyczne maszyny indukcyjnej klatkowej zasilanej z falownika prądu. Przedstawiono trzy układy regulacji sterowania multiskalarnego z czego dwa są nowe. Rozważania teoretyczne zweryfikowano za pomocą badań symulacyjnych.
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Photovoltaic solar cells and modules as the source of electricity in the world and its future in Poland
PublicationJedną z metod ograniczenia emisji CO2 na świecie i w Polsce jest zastępowanie paliw kopalnych odnawialnymi źródłami energii. Systemy fotowoltaiczne, generujące energie elektryczną, są uważane za technologię wpisująca się w politykę zrównoważonego rozwoju dzięki znacznemu postępowi technologicznemu w zakresie ich wytwarzania i znacznej redukcji kosztów tych systemów.W artykule naświetlono postęp, jaki dokonał się w tej dziedzinie...
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Application of atmospheric pressure microwave plasma source for hydrogen production from ethanol
PublicationIn contrast to conventional technologies of hydrogen production like water electrolysis or coal gasification we propose a method based on the atmospheric pressure microwave plasma. In this paper we present results of the experimental investigations of the hydrogen production from ethanol in the atmospheric pressure plasma generated in waveguidesupplied cylindrical type nozzleless microwave (915 MHz and 2.45 GHz) plasma source (MPS)....
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Automatic sound source localization in disturbing conditions using acoustic vector sensors
PublicationA concept, practical realization and applications of a passive acoustic radar to automatic localization and tracking of sound sources in disturbing conditions were presented in the paper. The device consists of the new kind of multichannel miniature sound intensity sensors and a group of digital signal processing algorithms. The sensitivity of the realized acoustic radar was examined in free sound field. Several kinds of sound...
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Evaluation of Open Source SIEM for Situation Awareness Platform in the Smart Grid Environment
PublicationThe smart grid as a large-scale system of systems has an exceptionally large surface exposed to cyber-attacks, including highly evolved and sophisticated threats such as Advanced Persistent Threats (APT) or Botnets. When addressing this situation the usual cyber security technologies are prerequisite, but not sufficient. The smart grid requires developing and deploying an extensive ICT infrastructure that supports significantly...
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Non-isolated resonant quasi-Z-source network DC–DC converter
PublicationA novel non-isolated resonant quasi-impedance (quasi-Z)-source network DC–DC converter is proposed. The resonant impedance source network is derived from the quasi-Z-source network by including the autotransformer-based resonant cell instead of the second inductor of the quasi-Z-network. The leakage inductance of the autotransformer and two resonant capacitors connected in series with the autotransformer windings constitute a high-frequency...
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Boron doped Nanocrystalline Diamond-Carbon Nanospike Hybrid Electron Emission Source
PublicationElectron emission signifies an important mechanism facilitating the enlargement of devices that have modernized large parts of science and technology. Today, the search for innovative electron emission devices for imaging, sensing, electronics, and high-energy physics continues. Integrating two materials with dissimilar electronic properties into a hybrid material is an extremely sought-after synergistic approach envisioning a...
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Liquefaction of alder wood as the source of renewable and sustainable polyols for preparation of polyurethane resins
PublicationLiquefaction of wood-based biomass gives different polyol properties depending on the reagents used. In this article, alder wood sawdust was liquefied with glycerol and poly(ethylene glycol) solvents. Liquefaction reactions were carried out at temperatures of 120, 150 and 170 °C. The obtained bio-polyols were analyzed in order to establish the process efficiency, hydroxyl number, acid value, viscosity and structural characteristics...
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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...
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Diatoms Biomass as a Joint Source of Biosilica and Carbon for Lithium-Ion Battery Anodes
PublicationThe biomass of one type cultivated diatoms (Pseudostaurosira trainorii), being a source of 3D-stuctured biosilica and organic matter—the source of carbon, was thermally processed to become an electroactive material in a potential range adequate to become an anode in lithium ion batteries. Carbonized material was characterized by means of selected solid-state physics techniques (XRD, Raman, TGA). It was shown that the pyrolysis...
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Modular high precision high current source for special applications — Simulation and verification
PublicationThis paper presents selected issues concerning realization of high precision high current source for special applications, where high demands of output parameters of such device are required. A new 80 kW prototype of modular high precision high current source is presented, where output current accuracy reaches 5x10-5. This paper presents also results of operation of the simulation model and of the prototype converter. In order...
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Dobre praktyki i narzędzia open source w zwinnym wytwarzaniu oprogramowania
PublicationZwinne wytwarzanie oprogramowania stało się bardzo popularne. Na podstawie projektu MOST Wiedzy przedstawiono procesy i narzędzia wspierające wytwarzanie oprogramowania na Politechnice Gdańskiej. Metodologia DDD (domain-driven design) wspierana przez repozytorium GIT oraz tzw. proces “cherry picking” powoduje, że proces wytwarzania oprogramowania jest elastyczny i efektywny. Dodatkowo wprowadzenie elementów CI (continuous integration),...
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Comparison of Impedance-Source Networks for Two and Multilevel Buck–Boost Inverter Applications
Publicationmpedance-source networks are an increasingly popular solution in power converter applications, especially in single-stage buck-boost power conversion to avoid additional front-end dc-dc power converters. In the survey papers published, no analytical comparisons of different topologies have been described, which makes it difficult to choose the best option. Thus, the aim of this paper is to present a comprehensive analytical comparison...
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Immune escape of B-cell lymphoblastic leukemic cells through a lineage switch to acute myeloid leukemia
PublicationAcute leukemia (AL) with a lineage switch (LS) is associated with poor prognosis. The predisposing factors of LS are unknown, apart from KMT2A rearrangements that have been reported to be associated with LS. Herein, we present two cases and review all 104 published cases to identify risk factors for LS. Most of the patients (75.5%) experienced a switch from the lymphoid phenotype to the myeloid phenotype. Eighteen patients (17.0%)...
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Gallic Acid-Functionalized, TiO2-Based Nanomaterial—Preparation, Physicochemical and Biological Properties
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Halina Szeląg prof. dr hab. inż.
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Lias: sources and documents relating to the early modern history of iedeas
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LIAS-Journal of Early Modern Intellectual Culture and its Sources
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Nederlands tijdschrift voor de zorg aan mensen met verstandelijke beperkingen
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Feit en fictie: tijdschrift voor de geschiedenis van de representatie
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Macromodels for efficient FEM simulations of waveguides and resonators
PublicationThis paper introduces a novel technique for enhancing the efficiency of the finite element method (FEM) by incorporating special modules, called macromodels, into the standard eigenvalue formulation. The number of unknowns in the separated macromodel subdomain can be significantly reduced by orthogonal projection, using the efficient nodal order reduction algorithm. The idea of macromodels implementation is demonstrated on a simple...
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Molecular properties with dual basis set methods
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IPNES - Interpreted Petri Net for Embedded Systems
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Verification of the fit to user profiles for UML tools
PublicationDopasowanie do profilu użytkownika ma wpływ na efektywność pracy użytkownika. W referacie postawiono pytanie, czy narzędzia UML rzeczywiście wspomagają pracę konkretnych ról w procesie wytwarzania oprogramowania. W ramach prac wykonano następujace zadania: opisano profile użytkowników narzędzi UML; wyodrębniono cechy narzędzi UML, które mają wpływ na dopasowanie do profili użytkowników; zaprojektowano model pokazujący związek pomiędzy...
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Developing an Ontology from Set of Experience KnowledgeStructure
PublicationWhen referring to knowledge forms,collecting for all decision eventsin a knowledge-explicit way becomes a significant ask for any company. Set of experience knowledge structure can assis in accomplishing this purpose.However,after collecting,distributing and sharing that knowledge as adecisional DNA is even a more important advance.Distributing and sharing companies' decisional DNA through an efficient development of Ontologies...
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Some aspects surface cooling by impinging jet
PublicationW pracy przedstawiono wyniki badań wymiany ciepła, uskoku hydraulicznego i stabilności podczas napływu strugi na powierzchnię ciała stałego.
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Comparision of Methods for Determination of Potential Evapotransportation (PET)
PublicationPotencjalna ewapotranspiracja (PET) jest traktowana jako indeks maksymalnej, możliwej ewapotranspiracji i jest wielkością często używaną w modelach hydrologicznych. W pracy porównano 4 modele obliczania PET: Konstantinowa, Turca, Thorntkwaita i Penmana. Są to metody o różnym stopniu dokładności. Przykładowe obliczenia przeprowadzono dla pomiarów ze stacji Bielnik, leżącej w pobliżu Gdańska.
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Ground improvement with in-situ wet soil mixing
PublicationOpisano rozwój technologii mieszania wgłębnego gruntu na świecie i w Polsce. Przedstawiono bliżej aktualnie wykorzystywane metody mieszania, wprowadzane przez specjalistyczne firmy. W syntetyczny sposób podsumowano zasady projektowania oraz doświadczenia wykonawcze. Zamieszczono bliższe informacje odnośnie kilku przykładów zastosowania w Polsce.
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May dithiophosphoric acid participate in the set process?
PublicationZastosowano otrzymane S-tioacyloditiofosforany jako odczynniki tioacylujące do syntezy kwasów tiohydroksamowych. Dla większości N-alkilohydroksyloamin produktem tej reakcji były żądane kwasy tiohydroksamowe. Natomiast gdy substratem jest hydroksyloamina zawierająca duży objętościowo podstawnik na atomie azotu lub gdy posiada dwa podstawniki na atomie azotu w reakcji tej tworzą się wyłącznie odpowiednie O-tioacylohydroksyloaminy....
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Modal FEM Analysis of Ferrite Resonant Structures
PublicationThe finite-element method (FEM) is applied for modal analysis of ferrite-loaded spherical resonators. To improve the efficiency of the numerical calculations, the body-of-revolution (BOR) technique is utilized. Due to the frequency-dependent ferrite permeability, FEM leads to a nonlinear eigenvalue problem that is challenging to solve. To this end, Beyn’s method is proposed. The effectiveness of the proposed approach is confirmed...
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Study of displacements of a bridge abutment using FEM
PublicationSteel sheet piles are often used to support excavations for bridge foundations. When they are left in place in the permanent works, they have the potential to increase foundation bearing capacity and reduce displacements; but their presence is not usually taken into account in foundation design. In this article, the results of finite element analysis of a typical abutment foundation, with and without cover of sheet piles, are presented...
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THE INFLUENCE OF QUESTION SET ON STUDENT QUIZ RESULTS
PublicationThe advent of e-Learning tools allowing for automated online test grading will probably increase the frequency of using tests in technical education. The same tools may provide for measures of test question quality. By purposely crafting question sets, test grading may serve different goals. The paper contains examples and test study with score histograms.
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CFD and FEM model of an underwater vehicle propeller
PublicationDuring the project execution of design and optimization the Remotely Operated Vehicle (ROV) research on its propulsion has been carried out. The entire project was supported by CFD and FEM calculations, which taking into account the characteristics of underwater vehicle. One of the tasks was to optimize the semi-open duct for horizontal propellers, which provided propulsion and controllability in horizontal plane. In order to...
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WŁAŚCIWOŚCI MECHANICZNE TWORZYWA PET – PRZEGLĄD LITERATURY
PublicationW artykule scharakteryzowano wpływ budowy mikrostrukturalnej jak i warunków otoczenia na odpowiedź mechaniczną tworzywa PET. Z mikroskopowego punktu widzenia na mechaniczne i termiczne właściwości tworzywa PET największy wpływ mają procesy orientowania i krystalizowania tworzywa. W ujęciu makroskopowym właściwości mechaniczne są ujmowane za pomocą parametrów uzyskanych z odpowiedzi mechanicznych na zadane wymuszenia (np. badań...
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Advances in CSI-fed induction motor drives
PublicationThe application of current source inverters (CSI)in induction motor (IM) drives offers a number of advantages,including: voltage boosting capability, natural shoot-throughshort-circuit protection and generation of sinusoidal voltages.The exact generation of sinusoidal voltages is possible thanks tothanks to the effect of the output ac filter capacitors and mayimprove the accuracy of sensorless IM control. The eliminationof high...
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Właściwości mechaniczne tworzywa PET - przegląd literatury
PublicationThe article describes the influance of the microstructure and environment conditions on the mechanical properties of PET material. From the microskopic point of view, mechanical and thermal properties of PET material have the biggest influance on orientation and crystallization processes of material. From the macroskopic point of view mechanical properties can be described by parameters derived from strees-strain mechanical answers...
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Case study methodology. Few conceptual considerations.
PublicationThis paper contributes to the debate on case study as methodological approach. It shows several issues concerning its major advatangeus and disadvantageus
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Prediction of coking dynamics for wet coal charge
PublicationA one-dimensional transient mathematical model describing thermal and flow phenomena during coal coking in an oven chamber was studied in the paper. It also accounts for heat conduction in the ceramic oven wall when assuming a constant temperature at the heating channel side. The model was solved numerically using partly implicit methods for gas flow and heat transfer problems. The histories of temperature, gas evolution and internal...
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Smart Weighing Scale with Feet-Sampled ECG
PublicationIn a smart home, health and well-being monitoring systems could be embedded in everyday devices providing a pervasive care. A home bathroom scale is an example of such a device, typically used to measure body weight and very often its composition (e.g. body water/fat percentage). In this paper, we analyzed a potential use of the bathroom scale to measure electrocardiogram (ECG) from electrodes located on the scale's tile. In particular...
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Control of a vapour microturbine set in cogeneration applications
PublicationSystems with microturbines are implemented for local generation of heat and electricity. This paper presents the analysis of control concepts for a vapour microturbine set with a generator with permanent magnets, intended to work in small heat and power plants. Control system variants differed by the selection of controlled signals and set parameters. Possible ways of control were discussed and compared with experimentally determined...
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Wysokoczęstotliwościowy przekształtnik z tranzystorami SiC JFET
PublicationW referacie przedstawiono konstrukcję oraz wyniki badań trójfazowego falownika napięcia zbudowanego z wykorzystaniem diod Schottky oraz tranzystorów JFET z węglika krzemu (SiC). Znacznie krótsze czasy przełączeń tych elementów w porównaniu z tranzystorami IGBT i diodami na bazie krzemu (Si) umożliwiają pracę układu z częstotliwością 100 kHz i wyższą. Duża stromość narastania napięcia rzędu dziesiątek kV/µs powoduje problemy EMC...
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FEM approach to modeling of an irregular trabecular structure
PublicationThe aim of the study is elaboration of a method for creating irregular scaffolds that can be used to model the behaviour of trabecular bone placed in the proximal epiphysis of the femur. The scope of the study encompasses creating six numerical models of irregular scaffolds (two solid irregular scaffolds, two shell irregular scaffolds and two shell irregular scaffolds with fortification) and performing numerical analysis of the...
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Dissimilar underwater wet welding of HSLA steels
PublicationThe high-strength low-alloy S460ML and S460N steels were chosen for underwater wet welding of dissimilar T-joints using covered electrodes. For improving the quality of joints, the temper bead welding (TBW) method was used. The application of TBW in pad welding conditions has been investigated earlier but the possibility of usage of this technique in welded joints was not analyzed. The main aim of the study was to check the influence...
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On bipartization of cubic graphs by removal of an independent set
PublicationWe study a new problem for cubic graphs: bipartization of a cubic graph Q by deleting sufficiently large independent set.
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State Observer for Doubly-fed Induction Generator
PublicationIn the paper a new state observer for doubly-fed generator has been proposed. In the new approach an extended mathematical model of the doubly fed generator is used to form equations of the introduced z type observer. Stability of the observer has been verified through poles placement analyses. The active and reactive powers of the generator are controlled by a nonlinear multiscalar control method. Simulation and experimental results...
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A two-scale (FEM-DEM) approach for concrete
PublicationArtykuł omawia dwu-skalowe podejście do betonu przy wykorzystaniu modelu Mes i DEM. Metodę elementów skończonych zastosowano na poziomie makro. Na poziomie mikro zastosowano metodę elementów dyskretnych. Macierz sztywności wyznaczono na podstawie tensora naprężeń wyznaczonego w skali mikro. Wyniki numeryczne dwusalowe porównano z wynikami dyskretnymi dla całego obszaru.
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Application of matching pursuit based method to identify sources of time-vary magnetic field
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Measurement of selected characteristics of low-coherence optical signal sources for optical coherence tomography
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Mercury emission to the atmosphere from anthropogenic sources in Europe in 2000 and their scenarios until 2020
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Improving denitrification efficiency at the "Wschod" WWTP in Gdansk (Poland) - effects of different carbon sources
PublicationCelem badań było określenie wpływu dawkowania trzech różnych źródeł węgla (ścieków po oczyszczaniu mechanicznym, metanolu, ścieków gorzelnianych) na szybkość denitryfikacji, mierzoną w warunkach laboratoryjnych z osadem czynnym z oczyszczalni ścieków Gdańsk-Wschód. Największą szybkość procesu (4.8-5.2 mgN/(g*h)) zaobserwowano dla ścieków przemysłowych. Dodatkowo przeprowadzono badanie długości fazy adaptacji osadu do metanolu w...