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Search results for: cycles
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GLOBAL BIOGEOCHEMICAL CYCLES
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Hat problem on odd cycles
PublicationThe topic is the hat problem in which each of n players is randomly fitted with a blue or red hat. Then everybody can try to guess simultaneously his own hat color by looking at the hat colors of the other players. The team wins if at least one player guesses his hat color correctly, and no one guesses his hat color wrong; otherwise the team loses. The aim is to maximize the probability of a win. In this version every player can...
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Advanced Turbine Cycles with Organic Media
PublicationOrganic Rankine Cycle (ORC) power plants have become very popular and have found their applications in systems with renewable sources of energy. So far their overall efficiencies are not very impressive and only for the upper temperature of about 300 °C do they exceed 20%. A drawback of these cycles is the limitation of the cycle upper temperature due to the heat exchanger technology and the materials used. However, it is possible...
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On-line Ramsey Numbers of Paths and Cycles
PublicationConsider a game played on the edge set of the infinite clique by two players, Builder and Painter. In each round, Builder chooses an edge and Painter colours it red or blue. Builder wins by creating either a red copy of $G$ or a blue copy of $H$ for some fixed graphs $G$ and $H$. The minimum number of rounds within which Builder can win, assuming both players play perfectly, is the \emph{on-line Ramsey number} $\tilde{r}(G,H)$. In...
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Organic Supercritical Thermodynamic Cycles with Isothermal Turbine
PublicationOrganic Rankine cycles (ORC) are quite popular, but the overall efficiencies of these plants are rather very low. Numerous studies have been conducted in many scientific centers and research centers to improve the efficiency of such cycles. The research concerns both the modification of the cycle and the increase in the parameters of the medium at the inlet to the turbine. However, the efficiency of even these modified cycles rarely...
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The hat problem on cycles on at least nine vertices
PublicationThe topic is the hat problem in which each of n players is randomly fitted with a blue or red hat. Then everybody can try to guess simultaneously his own hat color by looking at the hat colors of the other players. The team wins if at least one player guesses his hat color correctly, and no one guesses his hat color wrong; otherwise the team loses. The aim is to maximize the probability of winning. In this version every player...
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Decomposing Cavities in Digital Volumes into Products of Cycles
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Alternative cogeneration thermodynamic cycles for domestic ORC
PublicationThe Organic Flash Cycle (OFC) is suggested as a vapor power cycle that could potentially improve the efficiency of utilization of the heat source. Low and medium temperature finite thermal sources are considered in the cycle. Additionally the OFC’s aim is to reduce temperature difference during heat addition. The study examines 2 different fluids. Comparisons are drawn between the OFC and an optimized basic Organic Rankine Cycle...
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Optimization of steam cycles with respect to supercritical parameters
PublicationArtykuł zawiera analizę budowanych aktualnie bloków nadkrytycznych stosowanych na świecie. W pracy przeprowadzono analizę obiegów z pojedynczym oraz podwójnym przegrzewem międzystopniowym dodatkowo z regeneracyjnym podgrzewem wody zasilającej odpowiednio z sześcioma, siedmioma, ośmioma, dziewięcioma oraz dziesięcioma wymiennikami regeneracyjnymi. Obliczenia wykonywano dla różnych wartości temperatur i ciśnienia pary świeżej, różnych...
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Subcritical Thermodynamic Cycles with Organic Medium and Isothermal Expansion
PublicationThe efffciencies of the Organic Rankine Cycle (ORC) are not very high and only very seldom do they exceed 20%. The increase and optimization of initial parameters and certain modifications of the thermodynamic cycle make it possible to overcome these drawbacks. A new modified cycle has been described and analyzed in detail in the paper. Similarly to the Ericsson cycle for gas turbines, isothermal expansion in the turbine is suggested...
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Design Analysis of Micro Gas Turbines in Closed Cycles
PublicationThe problems faced by designers of micro-turbines are connected with a very small volume flow rate of working media which leads to small blades’ height and high rotor speed. In the case of gas turbines this limitation can be overcome by the application of a closed cycle with very low pressure at the compressor inlet (lower than atmospheric pressure). In this way we may apply a micro gas turbine unit of accepted efficiency to work...
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On some ramsey and turan-type numbers for paths and cycles
PublicationUdowodniono, że R(P_3,C_k,C_k)= R(C_k,C_k)= 2k - 1, dla nieparzystych k. Udowodniono, że R(P_4,P_4,C_k) = k + 2 oraz R(P_3,P_5,C_k) = k + 1 dla k > 2.
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The identification of operational cycles in the monitoring systems of underground vehicles
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The symmetrization method and limit cycles of vibro-impact systems
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Journal of Material Cycles and Waste Management
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Experimental investigation of Organic Rankine Cycles for domestic micro CHP
PublicationW 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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On Accuracy Modeling of Gas Turbine Cycles by the In-house COM-GAS Code
PublicationIn this paper, a comparison of accuracy modeling of gas turbine cycles between the basic (classical) model and the in-house COM-GAS code has been presented. The basic model uses a semi-perfect gas and well known projecting assumption. On the other hand, the computational flow mechanics (CFM) basis on a real gas by using thermodynamic tables. The thermodynamic analysis of thermal cycles, simply gas cycle GT8C and gas turbine cycle...
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Thermodynamic Cycles of Air Microturbine Power Plants Working on Biomass Fuels
PublicationThe gas turbine engine is modified to work as an air turbine set which consists, in the simplest arrangement, of a compressor, a heat exchanger and a turbine. Air is a working medium for both: the compressor and the turbine. This kind of air turbine set can be applied in power plants working on biomass fuels. In this solution we can burn fuels of varying parameters in the external combustion chamber without any harmful effects...
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Comparative study of selected fluids for use in supercritical Organic Ranking Cycles
PublicationIn view of increasing interest in improving energy efficiency of energy conversion devices, there is an increasing requirement of combined production of heat and electricity as well as demand for increased implementation of renewable energy resources. The micro cogenerative units utilizing the Organic Rankine Cycle are focusing the attention of many research centres around the world. In the present paper calculations of ORC cycles...
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The influence of the welding thermal cycles on corrosion resistance of duplex stainless steel
PublicationBadano skłonnośc strefy wpływu ciepła spoin ze stali dupleks do korozyjnego pękania narężeniowego. Wykonano próby korozyjne z wykorzystaniem metody SSRT w środowisku korozyjnym wrzącego MgCl2. Wykazano, że duży udział ferrytu w strukturze SWC pogarsza odpornośc na korozję. Badania metalograficzne na mikroskopie lektronowym wykazały różne sposoby propagacji pęknięcia zależnie od zawartości austenitu w strukturze SWC.
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HIERARCHICAL CYCLES IN MODERN POWER SYSTEMS – EXERGY ANALYSIS UNDER PART LOADS
PublicationThe aim of the paper is to investigate thermodynamic efficiency of advanced hierarchic power cyclesunder partial loads by using of exergy analyze. Advanced hierarchical power systems arecomposed of few energy conversion cycles, most common are steam and gas cycles in various configurations, but they may contain fuel cells, ORC, lithium bromide absorption chillers and others. Moreover hierarchical cycles can be powered by several...
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The role of the combined nitrogen-sulfur-carbon cycles for efficient performance of anammox-based systems
PublicationThe combined anammox/mixotrophic denitrification process was conducted in two granular sequencing batch reactors (SBRs) during a 200-day operation. Both reactors were fed with synthetic medium, but SBR2 was enriched with additional sulfate (SO4 2 ) which influenced sulfate reduction ammonium oxidation (SRAO) and heterotrophic reduction of SO4 2 by sulfate reducing bacteria. It was hypothesized that the addition of SO4 2 could...
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f-Cycles - a new approach to providing fast service recovery at low backup capacity overhead
PublicationW artykule zaproponowano klasowy algorytm doboru tras przeżywalnych, wykorzystujący autorską koncepcję f-Cykli ochronnych. Celem podejścia było zminimializowanie wartości czasu odtwarzania uszkodzonych strumieni ruchu. Cel ten został osiągnięty poprzez dostosowanie wielkości obszaru ochrony w zależności od klasy usług. Badania symulacyjne pokazały, że wykorzystując autorką koncepcję f-Cykli ochronnych, możliwe jest również jednoczesne...
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Influence of Different Biofuels on the Efficiency of Gas Turbine Cycles for Prosumer and Distributed Energy Power Plants
PublicationThe efficiency of a gas turbine can be affected by the use of different biofuels usually with a relatively Lower Heating Value (LHV). The paper evaluates the impact of calorific value of fuel on turbine performance and analyzes the possibilities of optimizing turbine construction from the point of view of maximum efficiency for a particular fuel. The several variants of design of small power microturbines dedicated to various biofuels...
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The experimental results of sorption cycles
Open Research DataExperimental studies of sorption cycles were carried out using a prototype research stand, which is a laboratory-scale model of an adsorption chiller. The Intensified Heat Transfer Adsorption Bed (IHTAB) reactor is adapted to the analysis and optimization of various parameters of adsorption systems, e.g., constructions and compositions of adsorption...
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Effectiveness of various types of coating materials applied in reinforced concrete exposed to freeze–thaw cycles and chlorides
PublicationThis study assesses the durability of coated and uncoated concrete surfaces protected with four different coating materials: water-soluble (BW), solvent-based (BR), mineral (MI), and epoxy (EP). The durability assessment includes evaluating the absorption rate of water, pull-off adhesion strength, and coating material thickness. Concrete samples were subjected to immersion in regular water and a 7% urea solution, followed by...
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Effectiveness of various types of coating materials applied in reinforced concrete exposed to freeze–thaw cycles and chlorides
PublicationThis study assesses the durability of coated and uncoated concrete surfaces protected with four Different coating materials: water-soluble (BW), solvent-based (BR), mineral (MI), and epoxy (EP). The durability assessment includes evaluating the absorption rate of water, pull-of adhesion strength, and coating material thickness. Concrete samples were subjected to immersion in regular water and a 7% urea solution, followed by cyclic...
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Calculation of the standard potentials of the dithiocarbamate/thiuram disulfide redox system via thermochemical cycles and computational electrochemistry .
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Investigations into Exhaust Particulate Emissions from Multiple Vehicle Types Running on Two Chassis Dynamometer Driving Cycles
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Body fat, energy balance and estradiol levels: a study based on hormonal profiles from complete menstrual cycles
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Comparative analysis of thermodynamic cycles of selected nuclear ship power plants with high-temperature helium-cooled nuclear reactor
PublicationThis paper presents a comparative analysis of thermodynamic cycles of two ship power plant systems with a high-temperature helium- cooled nuclear reactor. The first of them is a gas system with recuperator , in which classical gas chamber is substituted for a HTGR reactor (High Temperature Gas-cooled Reactor) . The second of the considered cycles is a combined gas-steam system where working medium flux from gas turbine outlet...
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A new duty cycles calculation method in pulse width modulation for direct matrix converters based on the shape function concept
PublicationPaper presents a new approach to duty cycle calculation in pulse width modulation for direct matrix converters. The essence of the proposed method is the use of elementary shape function of finite element. The algorithm for calculating the duty cycles was reduced to simple operations on the coordinates of input and output voltage vectors without trigonometric functions.
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Exhaust Emissions of Gaseous and Solid Pollutants Measured over the NEDC, FTP-75 and WLTC Chassis Dynamometer Driving Cycles
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CYP17Genotypes Differ in Salivary 17-β Estradiol Levels: A Study Based on Hormonal Profiles from Entire Menstrual Cycles
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Selected aspects of performance of organic Rankine cycles incorporated into bioenergy with carbon capture and storage using gasification of sewage sludge
PublicationThe study aims to investigate the application of the Organic Rankine Cycle (ORC) in the bioenergy with carbon capture and storage (BECCS) using gasification of sewage sludge. The tool used in the investigation is the Aspen Plus software with REFPROP property methods for calculating fluid properties. The reason for this study is that a detailed analysis of the proposed BECCS process flow diagram indicates that a certain amount of...
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Obstetric and perinatal outcomes following programmed compared to natural frozen-thawed embryo transfer cycles: a systematic review and meta-analysis
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Technical and economical analysis of combined cycles of gas turbine -steam turbine on pipeline compressor stations. Part II - Economic analysis
PublicationW pracy przedstawiono zagadnienie nadbudowy zespołów turbosprężarkowych, znajdujących się na tłoczni gazu ziemnego, odzyskowymi blokami parowymi. W analizie tego przedsięwzięcia wzięto pod uwagę kilka wariantów konfiguracji układu parowego oraz kilka wariantów uwzględniających zmienność obciążenia turbin gazowych napędzających kompresory. Dla układu parowego dobrano wszystkie podstawowe parametry, a następnie wykonano obliczenia...
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Technical and economical analysis of combined cycles of gas turbine - steam turbine on pipeline compressor stations. Part I - Technical analysis
PublicationW pracy przedstawiono zagadnienie nadbudowy zespołów turbosprężarkowych, znajdujących się na tłoczni gazu ziemnego, odzyskowymi blokami parowymi. W analizie tego przedsięwzięcia wzięto pod uwagę kilka wariantów konfiguracji układu parowego oraz kilka wariantów uwzględniających zmienność obciążenia turbin gazowych napędzających kompresory. Dla układu parowego dobrano wszystkie podstawowe parametry, a następnie wykonano obliczenia...
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Technical and economical analysis of combined cycles of gas turbine - steam turbine on pipeline compressor stations. Part II - Economic analysis
PublicationW pracy przedstawiono zagadnienie nadbudowy zespołów turbosprężarkowych, znajdujących się na tłoczni gazu ziemnego, odzyskowymi blokami parowymi. W analizie tego przedsięwzięcia wzięto pod uwagę kilka wariantów konfiguracji układu parowego oraz kilka wariantów uwzględniających zmienność obciążenia turbin gazowych napędzających kompresory. Dla układu parowego dobrano wszystkie podstawowe parametry, a następnie wykonano obliczenia...
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A Comparison of Carbon Dioxide Exhaust Emissions and Fuel Consumption for Vehicles Tested over the NEDC, FTP-75 and WLTC Chassis Dynamometer Test Cycles
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The TPR reduction profile of CeO2/10wt.%Cu with BCD - 2 cycles
Open Research DataThe dataset includes the TPR reduction profiles of CeO2/10wt.%Cu. The samples of nanoCeO2 impregnated with BCD-assisted precursor solution (betacyclodextrin). The dataset includes two cycles of reduction (samples oxidized in between)
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The TPR reduction profile of CeO2/10wt.%Mn with BCD - 2 cycles
Open Research DataThe dataset includes the TPR reduction profiles of CeO2/10wt.%Mn. The samples of nanoCeO2 impregnated with BCD-assisted precursor solution (betacyclodextrin). The dataset includes two cycles of reduction (samples oxidized in between)
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The TPR reduction profile of CeO2/10wt.%Co with BCD - 2 cycles
Open Research DataThe dataset includes the TPR reduction profiles of CeO2/10wt.%Co. The samples of nanoCeO2 impregnated with BCD-assisted precursor solution (betacyclodextrin). The dataset includes two cycles of reduction (samples oxidized in between)
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The TPR reduction profile of CeO2/10wt.%Ni with BCD - 2 cycles
Open Research DataThe dataset includes the TPR reduction profiles of CeO2/10wt.%Ni. The samples of nanoCeO2 impregnated with BCD-assisted precursor solution (betacyclodextrin). The dataset includes two cycles of reduction (samples oxidized in between)
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The TPR reduction profile of CeO2/10wt.%Fe with BCD - 2 cycles
Open Research DataThe dataset includes the TPR reduction profiles of CeO2/10wt.%Fe. The samples of nanoCeO2 impregnated with BCD-assisted precursor solution (betacyclodextrin). The dataset includes two cycles of reduction (samples oxidized in between)
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The TPR reduction profile of CeO2/10wt.%Co without BCD - 2 cycles
Open Research DataThe dataset includes the TPR reduction profiles of CeO2/10wt.%Co. The samples of nanoCeO2 impregnated without BCD-assisted precursor solution (betacyclodextrin). The dataset includes two cycles of reduction (samples oxidized in between)
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The TPR reduction profile of CeO2/10wt.%Mn without BCD - 2 cycles
Open Research DataThe dataset includes the TPR reduction profiles of CeO2/10wt.%Mn. The samples of nanoCeO2 impregnated without BCD-assisted precursor solution (betacyclodextrin). The dataset includes two cycles of reduction (samples oxidized in between)
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The TPR reduction profile of CeO2/10wt.%Ni without BCD - 2 cycles
Open Research DataThe dataset includes the TPR reduction profiles of CeO2/10wt.%Ni. The samples of nanoCeO2 impregnated without BCD-assisted precursor solution (betacyclodextrin). The dataset includes two cycles of reduction (samples oxidized in between)
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The TPR reduction profile of CeO2/10wt.%Cu without BCD - 2 cycles
Open Research DataThe dataset includes the TPR reduction profiles of CeO2/10wt.%Cu. The samples of nanoCeO2 impregnated without BCD-assisted precursor solution (betacyclodextrin). The dataset includes two cycles of reduction (samples oxidized in between)
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INNOVATIVE THERMODYNAMICAL CYCLES BASED ON ENHANCEMENT MASS, MOMENTUM, ENTROPY AND ELECTRICITY TRANSPORT DUE TO SLIP, MOBILITY, TRANSPIRATION, ENTROPY AND ELECTRIC JUMPS AS WELL AS OTHER NANO-FLOWS PHENOMENA
PublicationIn our work, a further development of the authors model of thermo-chemical flow of fuel, air, oxygen, steam water, species, ionic and electron currents within nano channels and nano-structures of novel devices is presented. Different transport enhancement models are taken into account -among them the most important are: the velocity slip connected with complex external friction, the Darcy mobility and the Reynolds transpiration....