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wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: MASTER CYCLE, RANKINE CYCLE, ULTRA-SUPERCRITICAL STEAM TURBINE, DOUBLE REHEAT CYCLE
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Meat freshness classification using ultra-fast gas chromatography
PublikacjaMeat constitutes an important component of human diet. In order to ensure that it is safe to consume, it is important to be able to determine whether a particular sample is fresh. To this end, an analysis of the headspace of pork, beef, and poultrywas performed over a period of seven days using ultra-fast gas chromatography. Compounds that may possibly be used as indicators of spoilage were identified. Based on the obtained results...
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Energy quality improvement by ultra rapid L. V. fault current limiting andinterrupting.
PublikacjaPrzedstawiono możliwość ograniczania rozprzestrzeniania się zapadów napięcia w sieciach elektroenergetycznych przy zwarciach przez zastosowanie łączników hybrydowych do ultra szybkiego ograniczania i wyłączania prądów zwarciowych. Referat ma na celu przedstawienie dotychczasowych osiągnięć prac badawczych w dziedzinie łączników ultra szybkich, a także poznanie opinii elektroenergetyki i odbiorców na temat celowości wprowadzenia...
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Pressure pulsations in turbine blade seal clearance
PublikacjaThe paper presents the results of numerical and experimental investigations into pressure forces generated in a turbine labyrinth seal. The experiments were performed on a single-stage air model turbine of the impulse type, while the numerical results were obtained by means of CFD Fluent Code. The performed experimental research and numerical calculations prove that in a shroud clearance the pressure pulsates and the effects of...
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Steam turbines governors in power system restoration process
PublikacjaThe paper discusses problems related to electric power system restoration process. The turbine controller operating mode influence in small subsystem is analyzed. There are considered abilities, advantages and drawbacks of the controller's two operating modes: power control and speed (frequen-cy) control, to rebuild electric power system from a single generating unit to a few parallel running generators.
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Classification of Polish wines by application of ultra-fast gas chromatography
PublikacjaThe potential of ultra-fast gas chromatography (GC) combined with chemometric analysis for classification of wine originating from Poland according to the variety of grape used for production was investigated. A total of 44 Polish wine samples differing in the type of grape (and grape growth region) used for the production as well as parameters of the fermentation process, alcohol content, sweetness, and others which characterize...
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Example of Using Particle Swarm Optimization Algorithm with Nelder–Mead Method for Flow Improvement in Axial Last Stage of Gas–Steam Turbine
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A low complexity double-talk detector based on the signal envelope
PublikacjaA new algorithm for double-talk detection, intended for use in the acoustic echo canceller for voice communication applications, is proposed. The communication system developed by the authors required the use of a double-talk detection algorithm with low complexity and good accuracy. The authors propose an approach to doubletalk detection based on the signal envelopes. For each of three signals: the far-end speech, the microphone...
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On a Method of Efficiency Increasing in Kaplan Turbine
PublikacjaThis paper presents a method of increasing efficiency in Kaplan-type turbine. The method is based on blade profile optimisation together with modelling the interaction between rotor and stator blades. Loss coefficient was chosen as the optimisation criterion, which is related directly to efficiency. Global optimum was found by means of Genetic Algorithms, and Artificial Neural Networks were utilised for approximations to reduce...
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A double-talk detector using audio watermarking
Publikacjaa novel approach to double-talk detection in the acoustic echo canceler is proposed. a hidden signature is embedded into the arriving signal, using the echo-hiding method. next detection of the presence of this signature in the microphone signal is performed. the results of the signature detection may be used by the acoustic echo canceler to stop or restart the adaptation process.
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Improvements to the STEAM-based teaching of architectural drawing
PublikacjaThe author of this article presents a systemic approach to improving the teaching of architectural drawing courses for engineers in the 21st Century. In this era of rapid development of digital technologies, the traditional teaching structure should be redefined to a purpose-oriented dynamic model. The existing, generally accepted teaching models have already proved successfully based on the practice-oriented STEAM programme, which...
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Efektywność studiów Master of Business Administration (MBA) w Polsce
PublikacjaW artykule oszacowano efektywność 28 programów studiów MBA w Polsce za pomocą „alokacyjnego” modelu New Cost (Tone 2002) należącego do nieparametrycznej metody DEA. Za nakłady przyjęto liczbę godzin programu MBA oraz jego koszt, zaś za wynik ogólny wskaźnik rankingowy studiów MBA w 2018 roku opracowany przez Perspektywy. Uzyskane wyniki świadczą o przeciętnej efektywności studiów MBA wynoszącej 68%, tylko sześć programów było...
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Ultra-Compact SIRC-Based Self-Triplexing Antenna with High Isolation
PublikacjaAn ultra-compact self-triplexing antenna realized on a substrate-integrated rectangular cavity (SIRC) is discussed in this study. The proposed structure employs two L-shaped slots and an in-verted U-shaped slot to radiate at three independent operating frequency bands. Three 50-ohm microstrip feed lines are used to excite the radiation in these slots. The operating frequency is individually tuned using the slot size. The slot placement...
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An algorithm for listing all minimal double dominating sets of a tree
PublikacjaWe provide an algorithm for listing all minimal double dominating sets of a tree of order $n$ in time $\mathcal{O}(1.3248^n)$. This implies that every tree has at most $1.3248^n$ minimal double dominating sets. We also show that this bound is tight.
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Underwater wet welding of S1300 ultra-high strength steel
PublikacjaMarine Structures Volume 81, January 2022, 103120 Underwater wet welding of S1300 ultra-high strength steel Author links open overlay panelJacekTomkówGrzegorzRogalski https://doi.org/10.1016/j.marstruc.2021.103120 Get rights and content Under a Creative Commons licenseopen access Highlights • Technological method of S1300 steel underwater weldability improving was proposed. • Number of cracks and hardness of welded joints was...
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On the internal efficiency of a turbine stage: classical and CFD definitions
PublikacjaAlmost entire fleet of steam turbines in Poland was designed between 1950 – 1980 with the use of the so-called zero dimensional (0D) calculation tools. For several years, design and modernization of the turbines occur in assistance with the state of the art methods that describe working fluid flow field based on 3D models and CFD codes. This cooperation between 0D and 3D codes requires exchange of overall, integral information...
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An upper bound for the double outer-independent domination number of a tree
PublikacjaA vertex of a graph is said to dominate itself and all of its neighbors. A double outer-independent dominating set of a graph G is a set D of vertices of G such that every vertex of G is dominated by at least two vertices of D, and the set V(G)\D is independent. The double outer-independent domination number of a graph G, denoted by γ_d^{oi}(G), is the minimum cardinality of a double outer-independent dominating set of G. We prove...
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Failure of austenitic stainless steel tubes during steam generator operation
PublikacjaThe article presents the failure process of austenitic stainless steels used in power devices, such as heat exchangers, steam generators, in terms of local corrosion: pitting, stress and intergranular corrosion, paying particular attention to welded joints area. The effect of steel chemical composition, microstructure, welding process and work environment was analyzed. The second part of the article presents the results of the...
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Infiltration in a double-porosity medium: Experiments and comparison with a theoretical model
PublikacjaThis paper presents experimental verification of the mathematical model of unsaturated flow in double‐porosity soils developed by the asymptotic homogenization method. A series of one‐dimensional infiltration experiments was carried out in a column filled with a double‐porosity medium composed of a mixture of sand and sintered clayey spheres arranged in a periodic manner. The unsaturated hydraulic properties of each porous material...
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Clean gas technologies - towards zero-emission repowering of Pomerania.
PublikacjaThe main aim this work is to show the different thermodynamic cycles which improve efficiency and/or decrease emission like: Cheng cycle, Szewalski cycle, LOTHECO cycle, hybrid pSOFC/GT cycle, inverse Brayton cycle, low-emission cycle and zero-emission cycle. For that purpose, cycles and results of analysis are first studied and, secondly, new concept is presented. The role of coupled analysis 0D and 3D in cycle’s devices is also...
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Noise in electrical double-layer capacitors (EDLCs)
PublikacjaWe present methods and problems of noise measurements in electrical double-layer capacitors (EDLC). Detailed noise equivalent electronic circuit is considered, and two possible ways of observations of random processes generated in the EDLCs structures are studied. We conclude that noise is a useful tool for characterization of the EDLC structures and their state-of-health, as in other materials and electronic devices. Eventual,...
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ANALYSIS OF THE PROJECT OF INNOVATIVE FLOATING TURBINE
PublikacjaThe design of a floating, innovative device for river water aeration and conversion of mechanical energy to electrical energy required the analysis of a number of geometrical and dynamic features. Such an analysis may be carried out on the basis of existing methods of numerical fluid mechanics. Models of pressures, forces and torques characteristic for the conversion of watercourse energy were developed for two basic concepts of...
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A lower bound on the double outer-independent domination number of a tree
PublikacjaA vertex of a graph is said to dominate itself and all of its neighbors. A double outer-independent dominating set of a graph G is a set D of vertices of G such that every vertex of G is dominated by at least two vertices of D, and the set V(G)D is independent. The double outer-independent domination number of a graph G, denoted by gamma_d^{oi}(G), is the minimum cardinality of a double outer-independent dominating set of G. We...
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The innovative experimental rig for wood steam drying at atmospheric pressure
PublikacjaThe high cost of fossil fuel and soaring consumer interest have encouraged people in the wood industry to look for faster and more energy-efficient methods to dry lumber. The air-steam mixture as medium of drying process was used in a laboratory kiln especially arranged for that reason. Experimental rig is based on automatic control system. At the time of drying measurements of the internal temperature, wood temperature, moisture...
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Design of a Patch Power Divider with Simple Structure and Ultra-Broadband Harmonics Suppression
PublikacjaThis paper introduces a simple H-shaped patch Wilkinson power divider (WPD), which provides ultra wide harmonics suppression band. The presented WPD designed at 1.8 GHz, and exhibits good performance at the operating bandwidth. In the proposed divider structure, two simple patch low-pass filters (LPFs) are employed at each branch, and three open ended stubs are added at each port. The proposed divider, implemented using the aforementioned...
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On the modelling of aerodynamic force coefficients for over-shroud seals of turbine stages
PublikacjaThis paper presents experimental investigations which made it possible to determine dynamic coefficients of labyrinth over-shroud seal of a model air turbine. The coefficients associate pressure forces with turbine rotor displacement, velocity and acceleration respective to turbine casing (linear model) and play important role in analyzing turbine-set dynamics. The obtained results indicated that involving serious errors can be...
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Influence of high temperature air-steam mixture application on time wood drying process
PublikacjaThe results of influence gas-steam mixture drying process on time wood drying process are presented. Wood species, namely oak (Quercus L.), beech (Fagus L.), pine (Pinus L.) and spruce (Picea K.) from the northern part of Pomerania region in Poland, were subject of air-steam mixture drying process. Main focus of those tests was to shorten the time of drying process and afterward to check properties of wood.
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The Method of reduction of aerodynamic forces generated in turbine blade seals
PublikacjaThe distibution of pressure in the seal gaps does not only affect the so called '' leakage losses'' and the turbine stage overall efficiency but also plays an important role in the generation of aerodynamic forces which may cause self-excited rotor vibrations. The paper describes a chamber seal applied for the reduction of the aerodynamic forces created in shroud seals. This kind of turbine seal was patented and tested.
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Explanation of Reduction of Pressure Forces in Turbine Chamber Seals
PublikacjaThe paper describes a chamber seal reducing the aerodynamic forces created in shroud seals. Asymmetrical pressure distribution (due to rotor-stator eccentricity) in the blade tip clearance leads to the creation of pressure forces acting on the blade shroud. By increasing the volume above the shroud, the pressure distribution becomes more uniform on the whole shroud circumference and the effect of rotor eccentricity is reduced....
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Explanation of Reduction of Pressure Forces in Turbine Chamber Seals
PublikacjaThe paper describes a chamber seal reducing the aerodynamic forces created in shroud seals. Asymmetrical pressure distribution (due to rotor-stator eccentricity) in the blade tip clearance leads to the creation of pressure forces acting on the blade shroud. By increasing the volume above the shroud, the pressure distribution becomes more uniform on the whole shroud circumference and the effect of rotor eccentricity is reduced....
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Rapid and Green Separation of Mono- and Diesters of Monochloropropanediols by Ultrahigh Performance Supercritical Fluid Chromatography–Mass Spectrometry Using Neat Carbon Dioxide as a Mobile Phase
PublikacjaThis study demonstrates the effect of column selectivity and density of supercritical carbon dioxide (SC-CO2) on the separation of monochloropropanediol (MCPD) esters, known as food toxicants, using SC-CO2 without addition of cosolvent in ultrahigh performance supercritical fluid chromatography–mass spectrometry (UHPSFC-MS). This study shows that over 20 2-monochloropropanediol (2-MCPD) and 3-monochloropropanediol (3-MCPD) mono-...
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On trees with double domination number equal to 2-domination number plus one
PublikacjaA vertex of a graph is said to dominate itself and all of its neighbors. A subset D subseteq V(G) is a 2-dominating set of G if every vertex of V(G)D is dominated by at least two vertices of D, while it is a double dominating set of G if every vertex of G is dominated by at least two vertices of D. The 2-domination (double domination, respectively) number of a graph G is the minimum cardinality of a 2-dominating (double dominating,...
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On trees with double domination number equal to total domination number plus one
PublikacjaA total dominating set of a graph G is a set D of vertices of G such that every vertex of G has a neighbor in D. A vertex of a graph is said to dominate itself and all of its neighbors. A double dominating set of a graph G is a set D of vertices of G such that every vertex of G is dominated by at least two vertices of D. The total (double, respectively) domination number of a graph G is the minimum cardinality of a total (double,...
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Ultra-broadband photonic internet
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Selection of a manufacturing technology variant for brake master cylinders by DFMA practices
PublikacjaPrzedstawiono koncepcję zintegrowanego, współbieżnego projektowania konstrukcji oraz procesów wytworzenia i montażu określonej klasy wyrobów tj. pomp hydraulicznych, stosowanych w układach hamulcowych pojazdów dostawczych. Omówiono ograniczenia i możliwości doboru alternatywnych technologii wytworzenia komponentów oraz realizacji procesu montażu, dla określonej postaci konstrukcyjnej wyrobu, a spełniającej wymagania technologiczności...
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Parametric Study on a Performance of a Small Counter-Rotating Wind Turbine
PublikacjaA small Counter-Rotating Wind Turbine (CRWT) has been proposed and its performancehas been investigated numerically. Results of a parametric study have been presented in this paper.As parameters, the axial distance between rotors and a tip speed ratio of each rotor have been selected.Performance parameters have been compared with reference to a Single Rotor Wind Turbine (SRWT).Simulations were carried out with Computational Fluids...
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The influence of high temperature wood drying conditions using air-steam mixture on its properties
PublikacjaThe results of properties change of beech wood after drying process are presented. The wood taken to experiments was from northern part of Pomeranian region in Poland. Before the main high temperature drying process using air-steam mixture, wood was initially dried in an open air conditions. The high temperature drying process was conducted at temperature 120oC, humidity 48%, flow rate of drying medium 2.5m/s and atmospheric pressure....
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Experimental investigation of Organic Rankine Cycles for domestic micro CHP
PublikacjaW artykule przedstawiono wyniki badań eksperymentalnych obiegu ORC wyposażonego w ekspander typu scroll (I etap badań) oraz ekspander utworzony na bazie turbinki pneumatycznej (II etap badań). Raportowane badania przeprowadzono na laboratoryjnym stanowisku realizującym obieg ''domowej'' mikrosiłowni parowej.
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Reduction of Derivative pipeline effort in water turbine
PublikacjaThe paper presents an approach to evaluate and reduce the effort of the derivative pipeline in a water turbine of a hydrostatic power station in its vulnerable spots. Potential places of the biggest effort of the structure, as well as the coefficient of displacement and safety factor related to them were identified using FEM numerical method. Pipeline reinforcement was designed and made based on FEM analysis. Original technology...
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An asymmetrical λ-foot of condensing steam flow in the IMP PAN nozzle
PublikacjaIn the present paper we have focused on the precise prediction of the spontaneous condensation phenomena in wet steam flow. Novelty of our approach lies on modelling both the moment of initiation of a phase transition, as well as the moment of its reverse progress - called here re-vaporization of the condensate phase. The practical issue is to elaborate of a model of spontaneous condensation/vaporization of water steam flow...
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Simulation-driven design of compact ultra-wideband antenna structures
PublikacjaPurpose–The purpose of this paper is to investigate strategies and algorithms for expedited designoptimization and explicit size reduction of compact ultra-wideband (UWB) antennas.Design/methodology/approach–Formulation of the compact antenna design problem aiming atexplicit size reduction while maintaining acceptable electrical performance is presented. Algorithmicframeworks are described suitable for handling various design situations...
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Thermal failure of a second rotor stage in heavy duty gas turbine
PublikacjaThe impulse mode of operation and the supply of various types of fuels causes frequent failures even in the heavy duty gas turbines. The paper presents the ravages of second rotor stage failure in a gas turbine. The excessive thermal elongation rise caused by fuel change was indicated as the main cause. We applied nonlinear numerical analysis, preceded by thermodynamic calculations of the turbine and visual inspection of the effects...
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The Application of Fluidic Sealing in Shrouded Gas Turbine Blades
PublikacjaThis paper presents a study conducted on a new gas turbine designed to limit leakage in the labyrinth seal. The slots in the fin are used to generate a bypass flow, which obstructs the flow in the gap above the fin. The method was tested numerically and experimentally beforehand using a simplified model without rotation or blade passages. In this paper, the validation of the method using a model of a turbine stage is shown. Reynolds-averaged...
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Model of the double-rotor induction motor in terms of electromagnetic differential
PublikacjaThe paper presents a concept, a construction, a circuit model and experimental results of the double-rotor induction motor. This type of a motor is to be implemented in the concept of the electromagnetic differential. At the same time it should fulfill the function of differential mechanism and the vehicle drive. One of the motor shafts is coupled to the direction changing mechanical transmission. The windings of the external rotor...
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Koncepcja skojarzonego układu produkcji energii elektrycznej i ciepła dla wybranej lokalizacji geotermalnej
PublikacjaW artykule przedstawiono rozważania nad koncepcją modernizacji systemu urządzeń energetycznych produkujących ciepło w ciepłowni geotermalnej Geotermii Podhalańskiej. Koncepcja ta ma na celu współprodukcję energii elektrycznej oraz ciepła przy wykorzystaniu entalpii fizycznej złoża wód geotermalnych. Tego typu rozwiązanie pozwoliłoby na częściowe pokrycie zapotrzebowania własnego na energię elektryczną, generując oszczędności w...
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Dynamic state assessment of the water turbine with the power of 600 kW
PublikacjaThe article discusses the results of experimental studies to assess the dynamic state of the turbine set with the Kaplan turbine. The dynamic assessment was made on the basis of appropriate standards, based on the measurement results of selected parameters of vibration, which have been measured for several states of the machine load. In addition, we attempted to identify the causes of the increased vibration levels based on the...
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1D Model Callibration on the Basis on 3D calculations for Tesla Turbine
PublikacjaThe paper presents the system of equations for axisymmetriclaminar flow, after averaging, through the width of interdisk slit ofTesla turbine. Coefficients were introduced, as a result ofaveraging, that improve the efficiency of 1D model. The minimalnumber of such coefficients was determined. The 1D modelmakes it possible to attain analytical solutions to an accuracylimited by these coefficients. Calibration of 1D model depends...
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Experimental tests of steel double-type balcony connections
PublikacjaThe paper presents analysis and results of experimental tests of full scale prefabricated balcony sets with dimensions (width × length × height): 2.0 m × 2.78 m × 0.186 m (in slope to 0.17 m). The sets consists of reinforced concrete slabs (balcony and ceiling) connected with each other by double-type balcony connections. The paper analyses the impact of variable parameters on the load carry capacity of elements. Additionally...
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Exergy analysis of a negative CO2 emission gas power plant based on water oxy-combustion of syngas from sewage sludge gasification and CCS
PublikacjaA power cycle with water-injected oxy-combustion (water cycle) is investigated by exergy analysis. It is fueled with syngas (aka. producer gas) from gasification of sewage sludge. The cycle is equipped with a spray-ejector condenser (SEC). CO2 is separated and compressed for transportation and storage. The net delivered electric power is 31% of the fuel exergy. The task efficiency is 39% when the flue gas bleed to gasification...
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Investigation of the aerodynamics of an innovative verticalaxis wind turbine
PublikacjaThis paper presents a preliminary three dimensional analysis of the transient aerodynamic phenomena occurring in the innovative modification of classic Savonius wind turbine. An attempt to explain the increased efficiency of the innovative design in comparison with the traditional solution is undertaken. Several vorticity measures such as enstrophy, absolute helicity and the integral of the velocity gradient tensor second invariant...
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Coplanar Waveguide Fed Ultra-Wideband Antenna Over the Planar and Cylindrical Surfaces
PublikacjaThe investigation of coplanar waveguide fed ultra-wideband antenna and the influence of the proximity of different materials on the reflection coefficients and radiation character-istics is presented. The antenna is composed of two circular coplanar strips which enclose slot aperture of similar shape and is designed on a thin and flexible substrate. From the modeling and experimental tests the antenna shows good performance in...