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Search results for: cnc turning
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Tuning a Hybrid GPU-CPU V-Cycle Multilevel Preconditioner for Solving Large Real and Complex Systems of FEM Equations
PublicationThis letter presents techniques for tuning an accelerated preconditioned conjugate gradient solver with a multilevel preconditioner. The solver is optimized for a fast solution of sparse systems of equations arising in computational electromagnetics in a finite element method using higher-order elements. The goal of the tuning is to increase the throughput while at the same time reducing the memory requirements in order to allow...
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Resonator-Loaded Waveguide Notch Filters with Broad Tuning Range and Additive-Manufacturing-Based Operating Frequency Adjustment Procedure
PublicationThis article presents a new class of ring-resonator-loaded waveguide notch filters with a broad tuning range, low cost, and improved performance. The proposed approach employs a comple-mentary asymmetric split ring resonator coupled to a microstrip transmission line and excited in a rectangular waveguide. An equivalent circuit model is proposed to explain the working principle of the proposed notch filter. The adjustment of the...
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Tuning of food wastes bioavailability as feedstock for bio-conversion processes by acoustic cavitation and SPC, SPS, or H2O2 as external oxidants
PublicationThe growing amount of food wastes makes them a suitable source for the generation of bioproducts through anaerobic digestion. Appropriate hydrolysis of the feedstock can enhance the efficiency of production of desired products. In this work, acoustic cavitation (AC) was employed as a pretreatment method to enhance hydrolysis stage by the modification of model (potato-based) food waste for increase in soluble chemical oxygen demand...
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Expedited Re-Design of Multi-Band Passive Microwave Circuits Using Orthogonal Scaling Directions and Gradient-Based Tuning
PublicationGeometry scaling of microwave circuits is an essential but challenging task. In particular, the employment of a given passive structure in a different application area often requires re-adjustment of the operating frequencies/bands while maintaining top performance. Achieving this necessitates utilization of numerical optimization methods. Nonetheless, if the intended frequencies are distant from the ones at the starting point,...
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Tuning of eg electron occupancy of MnCo2O4 spinel for oxygen evolution reaction by partial substitution of Co by Fe at octahedral sites
PublicationTo study the effect of partial Co substitution by Fe in the B site of MnCo2O4 spinel on its physicochemical and electrochemical properties, a series of MnCo2-xFexO4 powders (x=0.125; 0.250; 0.500; 0.750; 1.000) were synthesized by means of the sol-gel method. The produced powders were characterized by powder X ray diffraction (pXRD), scanning and transmission electron microscopy (SEM & TEM) coupled with energy dispersive spectroscopy...
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Knowledge-Based Expedited Parameter Tuning of Microwave Passives by Means of Design Requirement Management and Variable-Resolution EM Simulations
PublicationThe importance of numerical optimization techniques has been continually growing in the design of microwave components over the recent years. Although reasonable initial designs can be obtained using circuit theory tools, precise parameter tuning is still necessary to account for effects such as electromagnetic (EM) cross coupling or radiation losses. EM-driven design closure is most often realized using gradient-based procedures,...
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Application of the Optimization Methods to the Search of Marine Propulsion Shafting Global Equilibrium in Running Condition
PublicationFull film hydrodynamic lubrication of marine propulsion shafting journal bearings in running condition is discussed. Considerable computational difficulties in non-linear determining the quasi-static equilibrium of the shafting are highlighted. The approach using two optimization methods (the particle swarm method and the interior point method) in combination with the specially developed relaxation technique is proposed to overcome...
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BADANIA PILOTAŻOWE DRGAŃ NA WLOCIE DO SPRĘŻARKI TURBINY GAZOWEJ GTD 350
PublicationPodstawą diagnostyki maszyn wirnikowych są pomiary drgań ze względu na to że prawie wszystkie uszkodzenia maszyn powodują istotne zmiany wielkości je opisujących np. prędkości drgań. W eksploatacji maszyn wirnikowych najważniejsza jest ocena drgań obiektu na podstawie pomiarów wykonywanych na częściach niewirujących. Badania, których wyniki przedstawiono w referacie zostały przeprowadzone na stanowisku...
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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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The use of plate springs for preloading of a system of tapered roller bearings of a wind turbine gearbox
PublicationThe use of preloaded tapered roller bearings in wind turbine drive systems allows a transfer of load in the case of high variations of axial forces. The examined bearing system, a modification of a current design, consists of a pair of different sized bearings. Previous study showed the high sensitivity of tapered roller bearings on the existing radial interference. Dimensional tolerances used in the original design do not allow...
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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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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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Review of Small Gas Turbine Engines and Their Adaptation for Automotive Waste Heat Recovery Systems
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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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Exploring the meaning of night shift placement in nursing education: A European multicentre qualitative study
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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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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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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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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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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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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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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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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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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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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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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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Pyrolysis of Pruning Residues from Various Types of Orchards and Pretreatment for Energetic Use of Biochar
PublicationThe routine pruning and cutting of fruit trees provides a considerable amount of biowaste each year. This lignocellulosic biomass, mainly in the form of branches, trunks, rootstocks, and leaves, is a potential high-quality fuel, yet often is treated as waste. The results of a feasibility study on biochar production by pyrolysis of residues from orchard pruning were presented. Three types of biomass waste were selected as raw materials...
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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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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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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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Assessment of the usefulness of bacterial cellulose produced by Gluconacetobacter xylinus E25 as a new biological implant
PublicationBionanocellulose (BNC) is a clear polymer produced by the bacterium Gluconacetobacter xylinus. In our current study, “Research on the use of bacterial nanocellulose (BNC) in regenerative medicine as a function of the biological implants in cardiac and vascular surgery”, we carried out material analysis, biochemical analysis, in vitro tests and in vivo animal model testing. In stage 1 of the project, we carried out physical and...
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Spin-Resolved Band Structure of Hoffman Clathrate [Fe(pz)2Pt(CN)4] as an Essential Tool to Predict Optical Spectra of Metal–Organic Frameworks
PublicationParamount spin-crossover properties of the 3D-Hoffman metalorganic framework (MOF) [Fe(pz)2Pt(CN)4] are generally described on the basis of the ligand field theory, which provides adequate insight into theoretical and simulation analysis of spintronic complexes. However, the ligand field approximation does not take into account the 3D periodicity of the actual complex lattice and surface effects and therefore cannot predict a full-scale...
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Justyna Płotka-Wasylka dr hab. inż.
PeopleUrodziła się w Słupsku (24.03.1986).W 2005 roku ukończyła I Liceum Ogólnokształcące im. Jana II Sobieskiego w Wejherowie i rozpoczęła studia na Wydziale Chemicznym Politechniki Gdańskiej. Po ich ukończeniu w 2010 rozpoczęła pracę naukową na tej uczelni, uzyskując w 2014 roku stopień doktora nauk chemicznych. Tematem jej rozprawy doktorskiej, wykonywanej pod kierunkiem prof. Marka Biziuka oraz dr Caluma Morrisona (Uniwersytet w...
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Long-Term Care Nursing
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Critical Care Nursing Clinics of North America
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Journal of Korean Academy of Community Health Nursing
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Nursing management (Harrow, London, England : 1994)
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Pacific Rim International Journal of Nursing Research
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Nursing New Zealand (Wellington, N.Z. : 1995)
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Online Journal of Rural Nursing and Health Care
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International Journal of Community Based Nursing and Midwifery
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Journal of Korean Academic Society of Nursing Education
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JOURNAL OF PSYCHOSOCIAL NURSING AND MENTAL HEALTH SERVICES
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MCN-The American Journal of Maternal-Child Nursing
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