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Search results for: turning circle
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Analysis of turnouts with non-linear curvature of diverging track for different train running speeds
PublicationThe paper deals with the issue of shaping a variable curvature in the diverging track of the railway turnout. Solution without a circular arc in the central zone, comprising two zones of non-linear curvature, of the same length, having zero curvature values at the end points, was adopted as a model, on the basis of the previously conducted dynamic tests. Optimum type of curvature was selected from the point of view of the kinematic...
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Analysis of Modal Parameters Using a Statistical Approach for Condition Monitoring of the Wind Turbine Blade
PublicationThe primary objective of the presented paper is the numerical and experimental investigation related to developing a useful diagnostic method, which can be used for determining the site and size of damage in laminated shells of wind turbine blades. The described detection technique is based on the analysis of low frequencies bending vibrations mode shapes of rotor blades. The authors used the commonly applied statistics methods...
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Axial-Flux Permanent-Magnet Dual-Rotor Generator for a Counter-Rotating Wind Turbine
PublicationCoaxial counter-rotating propellers have been widely applied in ships and helicopters for improving the propulsion efficiency and offsetting system reactive torques. Lately, the counter-rotating concept has been introduced into the wind turbine design. Distributed wind power generation systems often require a novel approach in generator design. In this paper, prototype development of axial-flux generator with a counter-rotating...
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Review of Small Gas Turbine Engines and Their Adaptation for Automotive Waste Heat Recovery Systems
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ANALIZA AERODYNAMICZNA ŁOPAT NA PRZYKŁADZIE PROJEKTU DWUWIRNIKOWEJ TURBINY WIATROWEJ MAŁEJ MOCY
PublicationW artykule przedstawiono proces projektowania oraz analizy aerodynamicznej łopat turbiny wiatrowej z wykorzystaniem metody BEMT (ang. Blade Element Momentum Theory). Dokonano doboru profili aerodynamicznych oraz opisano procedurę wyznaczania optymalnego rozkładu kątów zwichrowania i długości cięciw profili w funkcji długości łopaty dla założonych parametrów wejściowych. Dokonano obliczenia działających sił oraz generowanej mocy...
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Zastosowanie absorpcyjnego urządzenia chłodniczego do poprawy efektywności pracy zespołu turbiny gazowej
PublicationWykazano analitycznie wpływ obniżenia temperatury powietrza atmosferycznego na wzrost mocy zespołu turbiny gazowej lub obniżenia zużycia paliwa. Wyznaczono efekty energetyczne i ekonomiczne dla ciepłowniczego zespołu turbiny gazowej możliwe do uzyskania podczas statystycznego sezonu. Ponadto dla skrajnych warunków temperaturowych sezonu letniego określono moc absorpcyjnego urządzenia chłodniczego niezbędnego do schłodzenia powietrza...
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Occurrence of Depressive Symptoms Among Older Adults after a Stroke in the Nursing Home Facility
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Complementary studies of residual stress distribution of repaired power plant steam turbine casing
PublicationRozkład i poziom naprężeń własnych w korpusach turbin badano za pomocą efektu Barkhausena oraz metodą nawiercania otworów. Badano również twardość. Korpusy były reperowane metodą zaspawania. Wykazano, iż zastosowana technologia nie wprowadza naprężeń o poziomie zagrażającym dalszej ekploatacji korpusu.
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Some problems of self-excited vibrations of turbine rotors. Part I: The theoretical method
PublicationPrzedstawiono teoretyczną metodę określania uszczelnienia nadbandażowego lub dławicy zupełnej, które odgrywa największą rolę w generowaniu samowzbudnych drgań typu aerodynamicznego wirników turbinowych. Drgania harmoniczne układu wirnika turbiny opisane są macierzowym równaniem, a wymuszenia aerodynamiczne określane metodą współczynników wpływu.
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Research into flows in turbine blade seals. Part III: Numerical calculations versus experiment
PublicationPrzedstawiono wyniki badań doświadczalnych przepływów w uszczelnieniu nadbandażowym stopnia turbinowego, przeprowadzonych na powietrznej turbinie modelowej. Rezultaty te porównano z wynikami badań numerycznych z zastosowaniem programu Fluent.
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Impact of steel grade on a ship colliding with an offshore wind turbine monopile supporting structure
PublicationOffshore wind power is experiencing rapid development around the world. The number of installations and their size is growing. Thousands of monopile support structures with diameters of 10 m and weights of 2000 tons will be installed in the coming years. Offshore wind power installations, often located close to the shore and shipping routes, pose a new challenge to ship safety. The study analyses the damages from an accidental...
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Performance and emission characteristics of diesel engines running on gaseous fuels in dual-fuel mode
PublicationConventional fossil fuels are being substituted with alternative green fuels because of their greenhouse gas emissions and pollution problems, which pose a severe threat to the environment. Several studies have reported the usage of biodiesel and gaseous fuels in both single and dual-fuel modes. Gaseous fuels such as producer gas, biogas, syngas, and hydrogen produced from renewable biomass could potentially be used along with...
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Investigation of the Efficiency of a Dual-Fuel Gas Turbine Combustion Chamber with a Plasma‒Chemical Element
PublicationThe study is devoted to the possibility of increasing the efficiency of the working process in dual-fuel combustion chambers of gas turbine engines for FPSO vessels. For the first time, it is proposed to use the advantages of plasma‒chemical intensification of the combustion of hydrocarbon fuels in the dual-fuel combustion chambers, which can simultaneously operate on gaseous and liquid fuels. A design scheme of a combustion chamber...
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Wind resource assessment and energy yield prediction for the small wind turbine on the Szubieniczne Hill
PublicationThe goal of this study is to preliminary assess the wind resources on the Szubieniczne Hill in order to predict the annual energy production for planned small wind turbine. The analyzed site is located close to the Gdańsk University of Technology campus, in complex urban environment additionally surrendered by forested hills. The assessment is based on Computational Fluid Dynamics simulations which allow to evaluate the wind energy potential...
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Exploring the meaning of night shift placement in nursing education: A European multicentre qualitative study
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Do new EU members have any chance of earning as much as Westerns do?
PublicationThis article examines the wage dispersion in the European Union in the last ten years (1996-2006). The research is motivated by the fact that New Members States (NMS) expected that wage convergence would occurred after their accession to the EU. At the same time Old Member States (OMS) have been increasingly concerned with the possibility that the EU enlargement could influence their local labor markets and wages through new channels...
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Early warning models against bankruptcy risk for Central European and Latin American enterprises
PublicationThis article is devoted to the issue of forecasting the bankruptcy risk of enterprises in Latin America and Central Europe. The author has used statistical and soft computing methods to program the prediction models. It compares the effectiveness of twelve different early warningmodels for forecasting the bankruptcy risk of companies. In the research conducted, the author used data on 185 companies listed on the Warsaw Stock Exchange...
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Optymalizacja działania wybranych układów kombinowanych silnik o zapłonie samoczynnym - turbina parowa
PublicationW artykule przedstawiono optymalizację wybranych układów kombinowanych silnik o zapłonie samoczynnym – turbina parowa. Do rozważań przyjęto układy kombinowane z kotłem utylizacyjnym jednociśnieniowym, z obiegiem jednociśnieniowym zawierającym dodatkowy odparownik niskoci-śnieniowy zasilający odgazowywacz oraz z obiegiem dwuciśnieniowym. Porównano uzyskane dodat-kowe moce, sprawności z wykorzystaniem ciepła zawartego w spalinach...
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Linux scheduler improvement for time demanding network applications, running on Communication Platform Systems
PublicationCommunication Platform Systems as ex. ATCA standard blades located in standardized chassis provides high level communication services between system peripherals. Each ATCA blade brings dedicated functionality to the system but can as well exist as separated host responsible for servicing set of task. According to platform philosophy these parts of system can be quite independent against another solutions provided by competitors....
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Changing the Ship Propulsion System Performances Induced by Variation in Reaction Degree of Turbocharger Turbine
PublicationArtykuł przedstawia szczegółowy model matematyczny układu napędu statku obejmującego: wolnoobrotowy silnik spalinowy okrętowy, śruba okrętowa oraz regulator prędkości kątowej. Model ten, następnie jest wykorzystany do badania symulacyjnego zachowania układu zarówno w stanach ustalonych jak i nieustalonych. Model jest zweryfikowany z wynikami eksperymentalnymi. Przedstawienie oryginalnej metody oceny wrażliwości układu względem...
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Diagnostic tolerances' evaluation method of the start-up exhaust temperature of a naval gas turbine
PublicationThe conducted investigations aimed to elaborate the method of marking diagnostic tolerances of the exhaust temperature of a gas turbine observed during engine's start-up process. The diagnostic tolerances were determined by means of statistical inference by creating the hypothesis about a normal distribution of the start-up exhaust temperature's dispersion in the initial operation moment, which was subsequently verified applying...
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Spectral Finite Element Method for Propagation of Elastic Waves in Wind Turbine Blades for SHM
PublicationW pracy przedstawiono model łopaty turbiny wiatrowej zbudowany z wykorzystaniem spektralnych elementów skończonych. Omówiono wyniki symulacji propagacji fal sprężystych i ich interakcji z uszkodzeniami w formie pęknięcia i delaminacji.
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Zagadnienia modelowania 3D spontanicznej kondensacji w części niskoprężnej turbiny parowej 200MW
PublicationPrzedstawiono wyniki obliczeń cieplno-przepływowych części NP turbiny parowej mocy 200MW wyposażonej w stopnień Baumanna. Obliczenia przeprowadzono z wykorzystaniem różnych sposobów modelowania pary, zweryfikowanych podstawowym eksperymentem ekspansji w dyszy de Lavala. Wyznaczono spadki ciśnień i moce poszczególnych stopni. Wyniki porównano z danymi pomiarowymi IMP PAN.
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Studies of the Modelling Accuracy of Steam Turbine Control Systems for Diagnostic Tests of Automatic Synchronizers
PublicationOne of the important factors that affect the reliable operation of the power system and the rapid restitution after disaster is a quick and effective combining synchronous electric power facilities to operate in parallel. Hence, diagnostics of automatic synchronizers at every stage of their life, from building a prototype, through the whole life, until removing such devices from the operation, is an extremely important and responsible...
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Field tests on hydrodynamic and hybrid operation of a bi-directional thrust bearing of a pump-turbine
PublicationIn vertical shaft pump turbines operating in pumped storage power plants an important role is played by a thrust bearing. Because of bi-directional character of operation, thrust bearing tilting pads have to be supported symmetrically, which is known to be unfavourable from the point of view of their performance. Large thrust bearings have to be carefully designed so as to minimise excessive thermo-elastic pad deformations. The...
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Design and computational fluid dynamics analysis of the last stage of innovative gas-steam turbine
PublicationResearch regarding blade design and analysis of flow has been attracting interest for over a century. Meanwhile new concepts and design approaches were created and improved. Advancements in information technologies allowed to introduce computational fluid dynamics and computational flow mechanics. Currently a combination of mentioned methods is used for the design of turbine blades. These methods enabled us to improve flow efficiency...
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Łukasz Skarżyński dr hab. inż.
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Tuning Ferulic Acid Solubility in Choline-Chloride- and Betaine-Based Deep Eutectic Solvents: Experimental Determination and Machine Learning Modeling
PublicationDeep eutectic solvents (DES) represent a promising class of green solvents, offering particular utility in the extraction and development of new formulations of natural compounds such as ferulic acid (FA). The experimental phase of the study undertook a systematic investigation of the solubility of FA in DES, comprising choline chloride or betaine as hydrogen bond acceptors and six different polyols as hydrogen bond donors....
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Determination of Peak Impact Force for Buildings Exposed to Structural Pounding during Earthquakes
PublicationStructural pounding between adjacent, insufficiently separated buildings, or bridge segments, has been repeatedly observed during seismic excitations. Such earthquake-induced collisions may cause severe structural damage or even lead to the collapse of colliding structures. The aim of the present paper was to show the results of the study focused on determination of peak impact forces during collisions between buildings exposed...
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Examination of fresh water chemistry in maritime Antarctica during austral summer 2017
PublicationDue to the fact that Antarctica is one of the least polluted places on Earth, it is a perfect place to observe the spread of global pollution. Therefore, research conducted on this continent is important due to the possibility of investigating the type of pollution and their way of transport. This work considers presence of organic contaminants in Maritime Antarctica in unexplored until now, Lions Rump headland. Qualitative and...
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ECHOES REDUCTION DURING DIGITAL DATA TRANSMISSION IN HYDROACOUSTIC CHANNEL – LABORATORY EXPERIMENT
PublicationThe possibility of using a hydroacoustic channel for digital data transmission is very limited. This is due to the effect of multipath propagation of the emitted acoustic wave and the damping of the mechanical wave in this medium, which increase with frequency. The first of these phenomena results in inter-symbol interference disturbances in data transmission systems, including even hundreds of symbols. Due to the number of reflections...
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Risk Diagnosis and Management with BBN for Civil Engineering Projects during Construction and Operation
PublicationThe authors demonstrate how expert knowledge about the construction and operation phases combined with monitoring data can be utilized for the diagnosis and management of risks typical to large civil engineering projects. The methodology chosen for estimating the probabilities of risk elements is known as Bayesian Belief Networks (BBN). Using a BBN model one can keep on updating the risk event probabilities as the new evidence...
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Volumetric and torque efficiency of pumps during start-up in low ambient temperatures
PublicationThe volumetric, torque and total efficiency of hydraulic pumps change during start-up in low ambient temperatures, as well as in thermal shock conditions, un-til they reach the set conditions. The time to reach steady-state conditions de-pends on many parameters: ambient temperature, flow rate, fluid temperature, design of hydraulic units. The author carried out tests of hydraulic pumps in the Hydraulics Laboratory of the Faculty...
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Concrete Compressive Strength Under Changing Environmental Conditions During Placement Processes
PublicationThe technological process of concrete production consists of several parts, including concrete mix design, concrete mix production, transportation of fresh concrete mix to a construction site, placement in concrete framework, and curing. Proper execution of these steps provides good quality concrete. Some factors can disturb the technological process, mainly temperature and excessive precipitation. Changing daily temperature and...
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Moisture content during and after high- and normal-temperature drying processes of wood
PublicationThe aim of the article is to present the results of moisture content of wood during and after the high-temperature steam and air–steam mixture drying processes and after an open air-drying process. The knowledge of moisture content changes of wood in the process of its drying is one of the important parameters to economy drying process and to keep the quality of dried wood. Wood samples, namely, spruce (Picea abies K.) and beech...
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Klasyfikator rozmyty użyteczny we wstępnym doborze profili łopatkowych turbin parowych
PublicationW artykule przedstawiona została próba stworzenia wstępnego modelu klasyfikatora rozmytego użytecnego we wstępnym doborze profili łopatkowych turbin parowych. Dobór odpowiedniego rozwiązania dokonywany jest na podstawie parametrów przepływu czynnika przez wieńce turbiny. Tego typu narzędzie decyzyjne może okazać się przydatne zarówno w przypadku modernizacji istniejących już obiektów, w których zdiagnozowane uszkodzenia wymuszają...
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OCCUPATIONAL RISK ASSESSMENT USING THE RISK SCORE METHOD DURING GEODETIC MEASUREMENTS
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Mathematical Modelling of a Seismic Isolation System to Protect Structures during Damaging Earthquakes
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Neural Oscillation During Mental Imagery in Sport: An Olympic Sailor Case Study
PublicationThe purpose of the current study was to examine the cortical correlates of imagery depending on instructional modality (guided vs. self-produced) using various sports-related scripts. According to the expert-performance approach, we took an idiosyncratic perspective analyzing the mental imagery of an experienced two-time Olympic athlete to verify whether different instructional modalities of imagery (i.e., guided vs. self-produced)...
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Network oscillations modulate interictal epileptiform spike rate during human memory
PublicationEleven patients being evaluated with intracranial electroencephalography for medically resistant temporal lobe epilepsy participated in a visual recognition memory task. Interictal epileptiform spikes were manually marked and their rate of occurrence compared between baseline and three 2 s periods spanning a 6 s viewing period. During successful, but not unsuccessful, encoding of the images there was a significant reduction in...
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A Simplified Method of Trend Removal to Determine Noise Observed During a Supercapacitor’s Discharging
PublicationIn this paper, new method of trend removal is proposed. This is a simplified method based on Empirical Mode Decomposition (EMD). The method was applied for voltage time series observed during supercapacitor discharging process. It assured the determination of an additive noise component after subtracting the identified trend component. We analyzed voltage time series observed between the terminals of the supercapacitor when discharged...
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Forest habitat loss and fragmentation in Central Poland during the last 100 years
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Environmental factors affecting the densities of owls in Polish farmland during 1980–2005
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Self-ignition of hydrogen–nitrogen mixtures during high-pressure release into air
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Quantifying the effective mobilized RAP content during hot in-place recycling techniques
PublicationThe utilization of in-place recycling techniques is capable of consuming 100% reclaimed asphalt pavement (RAP). Hot in-place recycling (HIR) is one of the promising techniques to rehabilitate the pavements suffering from minor cracking issues through heat scarification, additive injecting, mechanical mixing, and compacting. However, the main concern of using 100% RAP in HIR remains as how much RAP can be activated and mobilized...
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Pharmacokinetics of sufentanil during long-term infusion in critically ill pediatric patients
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Association between changes in air quality and hospital admissions during the holi festival
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Sea surface temperature distribution during upwelling along the Polish Baltic coast
PublicationAmong over 150 maps of sea surface temperature in the Polish Baltic coastal region derived from satellite data during the warm period of the year (April-October) in 2000-2002, 41 cases were noted where its distribution showed characteristic features indicating the occurrence of coastal upwelling. The fundamental parameters of range, probability of occurrence and temperature modification caused by water from deeper sea layers...
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Monitoring of myocardium state during off-pump coronary artery by-pass grafting
PublicationW pracy przedstawiono technikę pomiarową do oceny procesów zachodzących podczas operacji przesłowania aortalno-wieńcowego wymagających zatrzymania przepływu krwi. Zaproponiwany system i metoda pomiarowa przewidziane są do wykorzystania podczas opercacji na tzw. bijącym sercu. Pokazano przykłady rejestrowanych sygnałów przydatnych do oceny stanu mieśnia serca oraz dokonano oceny właściwości pomiarowych zastosowanych technik.
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Distribution and concentration of heavy metals in ash during thermal process sewage sludge
PublicationKażdego roku na świecie, obserwuje się znaczący wzrost produkcji osadów ściekowych. Przykładowo w 2006 roku, w Polsce ich ilość osiągnęła 1 mln ton w przeliczeniu na sucha masę, w tym ok. połowa pochodziła z oczyszczalni komunalnych. Problem ich zagospodarowania stanowi przedmiot zainteresowania wielu instytucji zajmujących się ochroną środowiska, zarówno w Polsce, jak i na całym świecie. Ich dotychczasowe wykorzystania polegało...