Wyniki wyszukiwania dla: ARCHIVES
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Comparison of state feedback and PID control of pressurizer water level in nuclear power plant
PublikacjaThe pressurizer water level control system in nuclear power plant with pressurized water reactor (PWR) is responsible for coolant mass balance. The main control goal is to stabilize the water level at a reference value and to suppress the effect of time-varying disturbances (e.g. coolant leakage in primary circuit pipeline system). In the process of PWR power plant operation incorrect water level may disturb pressure control or...
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Dynamic model of nuclear power plant turbine
PublikacjaThe paper presents the dynamic multivariable model of Nuclear Power Plant steam turbine. Nature of the processes occurring in a steam turbine causes a task of modeling it very difficult, especially when this model is intended to be used for on-line optimal process control (model based) over wide range of operating conditions caused by changing power demand. Particular property of developed model is that it enables calculations...
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Effect of microstructure on mechanical properties of BA1055 bronze castings
PublikacjaThe article presents research results performed on aluminum bronze CuAl10Fe5Ni5 (BA1032) castings used for marine propellers. Metallographic studies were made on light microscope and a scanning electron microscope to assess quantitatively and qualitatively the alloy microstructure. It has been shown that the shape, size and distribution of the iron-rich phase precipitates in bronze microstructure significantly affect its mechanical...
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Numerical solution of fractional neutron point kinetics in nuclear reactor
PublikacjaThis paper presents results concerning solutions of the fractional neutron point kinetics model for a nuclear reactor. Proposed model consists of a bilinear system of fractional and ordinary differential equations. Three methods to solve the model are presented and compared. The first one entails application of discrete Grünwald-Letnikov definition of the fractional derivative in the model. Second involves building an analog scheme...
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Numerical Simulations of X22CrMoV12-1 Steel Multilayer Welding
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Mechanical and Corrosion Properties of Magnesium-Bioceramic Nanocomposites
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Attempts to Modify Austenitic Steel with Carbon Nanotubes
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Determination of Flavonoids, Tannins and Ellagic acid in leaves fromRubus L. species
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Porous Magnesium Based Bionanocomposites For Medical Application
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Fluorescence use in minimally invasive metabolic and bariatric surgery — a systematic review of the literature
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Numerical Simulation of Duplex Steel Multipass Welding
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Some remarks on the pore water pressure dissipation patterns from the one-dimensional consolidation test
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Bounding approach to parameter estimation without prior knowledge on modeling error and application to quality modeling in drinking water distribution systems
PublikacjaW artykule rozważana jest estymacja parametrów modelu autoregresji z ruchoma średnią i sygnałem wejściowym (ARMAX) z wykorzystaniem przedziałowego modelu błędu. Zakłada się, że granice błędu struktury modelu są nieznane, bądź znane, ale bardzo konserwatywne. Dla zmniejszenia tego konserwatyzmu proponowane jest idea modeli punktowo-parametrycznych, w której występują zbiory parametrów i błędu modelu odpowiadające wszystkim wejściom....
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Structural analogues of reactive intermediates as inhibitors of glucosamine-6-phosphate synthase and phosphoglucose isomerase
PublikacjaCentra aktywne izomerazy fosfoglukozowej (PGI) oraz domeny izomerazowej (HPI) syntazy glukozamino-6-fosforanu (GlcN-6-P), wykazują podobieństwo ułożenia przestrzennego kluczowych reszt aminokwasowych, z wyjątkiem reszty Arg272 PGI i reszt Lys603 i Lys485 HPI. Dziesięć pochodnych D-heksitolo-6-P, kwasu 5-fosfoarabonowego i kwasu 6-fosfoglukonowego, strukturalnych analogów cis-enolaminy lub cis-enolanu, przypuszczalnych stanów przejściowych...
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Induced sheath voltages in 110 kV power cables – case study
PublikacjaThis paper considers electric shock hazard due to induced sheath voltages in 110 kV power cables. The purpose of this paper is to find an optimal configuration of the power cable system, taking into account electric shock hazard and ability of the system to transfer maximal power. A computer simulations on a computer model of the local power system, comprising high voltage power cables, were carried out. This model enables to analyse...
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Equitable and semi-equitable coloring of cubic graphs and its application in batch scheduling
PublikacjaIn the paper we consider the problems of equitable and semi-equitable coloring of vertices of cubic graphs. We show that in contrast to the equitable coloring, which is easy, the problem of semi-equitable coloring is NP- complete within a broad spectrum of graph parameters. This affects the complexity of batch scheduling of unit-length jobs with cubic incompatibility graph on three uniform processors to minimize...
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Multi-region fuzzy logic controller with local PID controllers for U-tube steam generator in nuclear power plant
PublikacjaIn the paper, analysis of multi-region fuzzy logic controller with local PID controllers for steam generator of pressurized water reactor (PWR) working in wide range of thermal power changes is presented. The U-tube steam generator has a nonlinear dynamics depending on thermal power transferred from coolant of the primary loop of the PWR plant. Control of water level in the steam generator conducted by a traditional PID controller...
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PROBABILISTIC ANALYSIS OF A SPACE TRUSS BY MEANS OF A MULTIDIMENSIONAL VARIABLE DESCRIPTION
PublikacjaThe objective of this paper is to present a variant of the point estimate method (PEM) to determine mean values and standard deviations of limit loads of engineering structures. This approach is illustrated by limit state analysis of a space truss, considering geometric and material imperfections. The calculations were performed for different random models, so the influence of random parameters on the limit load of the truss can...
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Numerical analysis of test embankment on soft ground using multi-laminate type model with destructuration
PublikacjaW artykule przedstawiono model wielopłaszczyznowy (multi-laminate) uwzględniający anizotropię struktury słabonośnych gruntów drobnoziarnistych. Anizotropia indukowana naprężeniem, która otrzymuje się przy zastosowaniu modeli wielopłaszczyznowych, jest dodatkowo wzmocniona poprzez wprowadzenie prekonsolidacji zależnej od orientacji przestrzennej. Model przedstawiono w wersji sprężysto-plastycznej, w której możliwa jest symulacja...
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Damage detection of a T-shaped panel by wave propagation analysis in the plane stress
PublikacjaW pracy zaprezentowano podejście obliczeniowe do analizy propagacji fal w płaskim stanie naprężenia. Problem brzegowo-początkowy podlega przestrzennej aproksymacji z użyciem wielowęzłowych, izoparametrycznych, czworobocznych elementów klasy C0. Macierze elementowe są całkowane numerycznie za pomocą kwadratury Gauss-Legendre-Lobatto. Aproksymację w dziedzinie czasu wykonano za pomocą algorytmu Newmarka. Symulacje numeryczne przeprowadzono...
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Fuzzy reasoning system design and assessment of load-bearing endoprostheses and their fabrication processes
PublikacjaZaproponowano piec zastosowan podejscia rozumowania rozmytego do rozwiazania problemów w dziedzinie biomechanikioraz inzynierii biomateriałów. Obejmuja one: (A) oszacowanie maksymalnych naprezen kontaktowych działajacych naendoproteze, (B) zaprojektowanie procesu spiekania dla otrzymania porowatego implantu, (C) opracowanie planu utleniania wcelu otrzymania struktury nanorurkowej na stopach Ti, (D) oraz (E) zaprojektowanie osadzania...
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Electrophysiological features in patients with sinus node dysfunction and vasovagal syncope
PublikacjaThe aim of the study was to identify electrophysiological criteria that can be used for identification of patients with sinus node dysfunction and concurrent vasovagal syncope.
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Advanced field investigations of screw piles and columns
PublikacjaPrzedstawiono opis badań pali i kolumn wkręcanych na terenowym poletku doświadczalnym, wykonanych w ramach projektu badawczego MNiSW. Badania statyczne pali i kolumn wykonano z zaawansowanym systemem do pomiaru rozkładu siły wzdłuż trzonów. Przedstawiono podstawowe wyniki badań z rozdziałem obciążenia na podstawę i pobocznicę pali i kolumn.
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The results of analyses of deep excavation walls using two different methods of calculation
PublikacjaPrzedstawiono wyniki obliczeń obudowy głębokiego wykopu dwukrotnie rozpieranej i dwukrotnie kotwionej w gruncie jednorodnym niespoistym. Obliczenia numeryczne wykonano metodą podpór sprężysto-plastycznych i metodą elementów skończonych. Zwrócono uwagę na istotne różnice w wynikach obliczeń. Zaproponowano wyjaśnienie przyczyn zaobserwowanych różnic w wynikach obliczeń otrzymanych z obu metod.
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A solution of non-linear differential problem with application to selected geotechnical problems
PublikacjaA certain non-linear differential equation containing a power of unknown function being the solution is considered with application to selected geotechnical problems. The equation can be derived to a linear differential equation by a proper substitution and properties of the operations G and S.
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Computing internodal conductivities in numerical modeling of two dimensional unsaturated flow on rectangular grid
PublikacjaW artykule porównano rozwiązania numeryczne dwuwymiarowego równania przepływu nienasyconego z użyciem różnych metod uśredniania współczynnika przewodności hydraulicznej między sąsiednimiwęzłami. Uwzględniono średnia arytmetyczną, geometryczną, "pod prad" oraz całkową, a także niedawno zaproponowany sposób uśredniania oparty na analizie przepływu ustalonego. Ten ostatni sposób okazałsię najbardziej uniwersalny, gdyż umożliwiał otrzymanie...
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A graphical approach to yield and boundary surfaces of selected hypoplastic constitutive equations
PublikacjaThe article describes how to identify the boundary and yield surface for hypoplastic constitutive equations proposed by Wu, Gudehus and Bauer. It is shown how to identify and plot the surfaces for any equation in this class. Calculation errors are analyzed characteristic for appleid set of numerical formulas. In the paper there are computer links to the source code prepared in the MATLAB system, based on istructions in the article....
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Dome over the Gdynia seaport building
PublikacjaThe paper presents the description of structure and the selected problems of the technical condition, as well as the strength analysis of the thin-walled reinforced concrete shell which has been making a covering of the main hall of the Gdynia Seaport Building through the last 80 years. The rectangle projection of four single curvature shells of the dome was shaped out of mutual perpendicular intersection of two cylindrical shells. The...
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DC-link voltage balancing in cascaded H-Bridge converters
PublikacjaIn the paper a DC-link voltage balancing strategy for multilevel Cascaded H-Bridge (CHB) converter is proposed. Presented solution bases on optimal choice of active vector durations in Space-Vector Pulse Width Modulation (SV-PWM). It makes it possible to DC-link voltages control and to properly generate the output voltage vector in the case of DC-link voltage unbalance. Results of simulation and experimental researches...
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Multipoint Ultrasonic Diagnostics System of Prestressed T-Beams
PublikacjaThis paper is devoted to the application of ultrasonic wave propagation phenomena for the diagnostics of prestressed, concrete, bridge T-beams. A multi-point damage detection system is studied with use of numerically obtained data. The system is designed to detect the presence of the material discontinuities as well as their location.
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Application of guided wave propagation in diagnostics of steel bridge components
PublikacjaEarly detection of potential defects and identification of their location are necessary to ensure safe, reliable and long-term use of engineering structures. Non-destructive diagnostic tests based on guided wave propagation are becoming more popular because of the possibility to inspect large areas during a single measurement with a small number of sensors. The aim of this study is the application of guided wave propagation in...
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Improving sensitivity of residual current transformers to high frequency earth fault currents
PublikacjaFor protection against electric shock in low voltage systems residual current devices are commonly used. However, their proper operation can be interfered when high frequency earth fault current occurs. Serious hazard of electrocution exists then. In order to detect such a current, it is necessary to modify parameters of residual current devices, especially the operating point of their current transformer. The authors proposed...
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Automotive fleet repair facility wastewater treatment using air/ZVI and air/ZVI/H2 O2 processes
PublikacjaAdvanced automotive fl eet repair facility wastewater treatment was investigated with Zero-Valent Iron/Hydrogen Peroxide (Air/ZVI/H2 O2 ) process for different process parameters: ZVI and H2 O2 doses, time, pH. The highest Chemical Oxygen Demand (COD) removal effi ciency, 76%, was achieved for ZVI/H2 O2 doses 4000/1900 mg/L, 120 min process time, pH 3.0. COD decreased from 933 to 227 mg/L. In optimal process conditions odor and...
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Curb-to-Barrier Face Distance Variation an a TB51 Bridge Barrier Crash Test Simulation
PublikacjaThis paper addresses the problem of road safety regarding barrier placement as relative to the curb. A short summary of existing regulations is presented. Numerical simulations using the explicit finite element system Ls- Dyna are shown. In the analysis, variable distance between the barrier and the curb is assumed. The obtained result reveals that the distance has little impact on the working width of the barrier.
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The Influence of the Chemical Composition of Selected Waste Materials from the Production of Copper on the Final Environmental Assessment
PublikacjaThis article presents qualitative and quantitative analysis of the waste produced by KGHM Polska Miedź. The waste has been analyzed according to its chemical composition and balanced in order to be reused and recycled. Special attention has been paid to mining industries producing the biggest amount of waste and ore enrichment businesses generating waste, which isn’t reused nowadays. Laboratory reseach has been conducted on floatation...
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The structurally similar TRFH domain of TRF1 and TRF2 dimers shows distinct behaviour towards TIN2
PublikacjaThe telomere repeat binding-factor 1 and 2 (TRF1 and TRF2) proteins of the shelterin complex bind to duplex telomeric DNA as homodimers, and the homodimerization is mediated by their TRFH (TRF-homology) domains. We performed molecular dynamic (MD) simulations of the dimer forms of TRF1TRFH and TRF2TRFH in the presence/absence of the TIN2TBM (TIN2, TRF-interacting nuclear protein 2, TBM, TRF-binding motif) peptide. The MD results...
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The 90th Birthday Jubilee of Professor Eugeniusz Bielewicz
PublikacjaOn the jubilee year of the 90th birthday of prof. Eugeniusz Bielewicz, a portrait of this eminent civil engineer and scholar is presented by his co-workers.
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Effect of Semiconductor Element Substitution on the Electric Properties of Barium Titanate Ceramics
PublikacjaThe investigated ceramics were prepared by a solid-state reaction from simple oxides and carbonates with the use of a mixed oxide method (MOM). The morphology of BaTi0.96Si0.04O3 (BTSi04) ceramics was characterised by means of a scanning electron microscopy (SEM). It was found that Si+4 ion substitution supported the grain growth process in BT-based ceramics. The EDS results confirmed the high purity and expected quantitative composition...
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Haemocompatibility Of Non-Functionalized And Plasmachemical Functionalized Detonation Nanodiamond Particles
PublikacjaThe purpose of this paper is to present the innovative design of microwave plasma system for modification of detonation nanodiamond particles (DNP) using a special rotating drum placed inside the reactor. Nanodiamond particles manufactured by detonation method reveal the biological activity depending on surface functionalization. Plasmachemical modification of detonation nanodiamond particles gives the possibility of controlling...
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THE POSSIBILITY OF USE OF LASER-MODIFIED Ti6Al4V ALLOY IN FRICTION PAIRS IN ENDOPROSTHESES
PublikacjaThe purpose of this paper is to show results of laser treatment at cryogenic conditions of the Ti6Al4V alloy used for orthopedic applications. That modification process ought to bring beneficial changes of microstructure and residual stresses in the surface layer. The paper presents the abrasive wear of the base and laser remelted material in association with ceramics Al2O3. Despite the surface cracking after laser treatment the...
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Formulation of spectral truss element for guided waves damage detection in spatial steel trusses
PublikacjaW pracy przedstawiono sformułowanie wielowęzłowego elementu spektralnego oraz odpowiedniego schematu całkowania ukierunkowanego na problem propagacji fal w kratownicach przestrzennych o dowolnej geometrii. Zaproponowane podejście nie ogranicza liczby węzłów w elemencie kratowym. Porównawcze rozwiązania numeryczne przeprowadzono dla konstrukcji idealnej (w stanie nieuszkodzonym) oraz dlakonstrukcji z miejscową nieregularnością w...
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Wave propagation analysis in spatial frames using spectral Timoshenko beam elements in the context of damage detection
PublikacjaPraca poświęcona jest zjawisku propagacji fal sprężystych w trójwymiarowych układach ramowych. W ramach teorii belek Timoszenki formułuje się wielowęzłowy element belkowy klasy C0 z sześcioma inżynierskimi stopniami swobody w każdym węźle. Zakłada się, że elementy są wykonane z jednorodnego, izotropowego materiału liniowo sprężystego. Zasadniczym celem artykułu jest sformułowanie szybkiego i wydajnego schematu całkowania po czasie....
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Numerical and Analytical Investigation of Aluminium Bracket Strengthening
PublikacjaThis paper focuses on an analytical and numerical investigation of aluminium brackets used to fasten light-weight curtain walls to building facilities. The authors propose a solution to increase the load capacity of aluminium brackets by means of additional cover plates (straps). This paper also includes a short survey of literature and material properties concerning the EN AW-6060 T6 aluminium alloy. This paper suggests an initiation...
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Non-proportional full-order Luenberger observers of induction motors
PublikacjaThe paper recapitulates recently conducted investigations of non-proportional Luenberger observers, applied to reconstruction of state variables of induction motors. Three structures of non-proportional observers are analyzed, a proportional-integral observer, modified integral observer and observer with integrators. Criteria for gain selection of the observer are described, classical ones based on poles, as well as additional,...
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Laser granulometer as an useful tool for selection of appropriate membranes used in the MIEX®DOC-UF/MF hybrid process
PublikacjaIn the study, particle size distribution of the MIEX® resin was presented. Such analyses enable to determinate whether presence of fine resin fraction may be the reason for unfavorable membrane blocking during water purification by the hybrid MIEX®DOC-microfiltration/ultrafiltration systems. Granulometric analysis of resin grains using the laser diffraction particle size analyzer (laser granulometer) was carried out as well as...
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Simulation of the remanence influence on the transient states in a single-phase multiwinding transformer
PublikacjaThis paper presents the mathematical model of a single-phase multi-winding core type transformer taking into account magnetic hysteresis phenomenon based on the feedback Preisach model (FPM). The set of loop differential equations was developed for a K-th winding transformer model where the flux linkages of each winding includes flux Φ common to all windings as a function of magneto motive force Θ of all windings. The first purpose...
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Moment resistance of I-section end-plate roof girder splices; a case study
PublikacjaThis article deals with the problem of determining the resistance of end-plate connections. A nonlinear FEM model of the joint was constructed in order to predict its carrying capacity. A standard code procedure was done as well. The analyses have been done to assess atypical end-plate joints designed and constructed as a part of roof structures.
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Dynamic variables limitation for backstepping control of induction machine and voltage source converter
PublikacjaDynamic 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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Numerical mesoscopic analysis of fracture in fine-grained concrete
PublikacjaArtykuł omawia wyniki analizy mezoskopowej procesu pękania w betonie podczas zginania. Obliczenia wykonano na poziomie mezo wykorzystując model degradacji sztywności z nielokalnym osłabieniem. Zbadano wpływ właściwości kruszywa, stref przejściowych, nacięcia oraz długości charakterystycznej mikrostruktury na zachowanie sie betonu.
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Application of extended Finite Element Method to cracked concrete elements - numerical aspects
PublikacjaArtykuł omawia zastosowanie rozszerzonej metody elementów skończonych do zarysowanych elementów betonowych. Obliczenia wykonano dla elementów poddanych zginaniu i mieszanemu ściskaniu - rozciąganiu. Wyniki porównano z doświadczeniami.