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Search results for: Stefan Chwin
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Studies on applicability of new solid-phase microextraction fibers for the selective extraction and determination of short - chain monocarboksylic acids
PublicationShort-chain monocarobxylic acids, sometimes referred to as volatile fatty acids (VFA), are a group of low molecular weight alkyl monocarboxylic acids that are widely distributed within the environment. These molecules contain any from 2 to 8 carbon atoms and originate from the anaerobic biodegradation of organic matter such as carbohydrates, proteins, and fats. These compounds are commonly found in the effluents from animal farming,...
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Carboxymethyl Starch/Medium Chain Fatty Acid Compositions: Rheological Changes During Storage and Selected Film Properties
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Comparing combined gas tubrine/steam turbine and marine low speed piston engine/steam turbine systems in naval applications
PublicationPorównano układy napędowe okrętowe kombinowane turbina gazowa- turbina parowa oraz spalinowy okrętowy silnik tłokowy wolnoobrotowy - turbina parowa. Porównywano moce oraz zużycie paliwa oraz parametry pary świeżej układu turbiny parowej.
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On energy, exergy, and environmental aspects of a combined gas-steam cycle for heat and power generation undergoing a process of retrofitting by steam injection
PublicationThe paper presents a study of retrofitting of a combined heat and power (CHP) plant aimed to increase the electric to heating power ratio. The modification would involve diverting part of the steam to the gas turbine, instead of letting it go to the steam turbine, using injection technique into a combustion chamber. Therefore, two potential retrofitting approaches are analyzed: steam injection gas turbine (STIGT) and combined steam...
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Balkony-stan zagrożenia.
PublicationArtykuł dotyczy opisu stanu technicznego balkonów zlokalizowanych w budynkach mieszkalnych pochodzących z różnych okresów realizacji
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Strefa rozwojowa Południowego Bałtyku w kreowaniu spójności Unii Europejskiej
PublicationStrefa Rozwojowa Południowego Bałtyku jest regionem o zasięgu przestrzennym od Szlezwiku-Holsztyna (Niemcy) od Łotwy. Przedstawiono diagnozę i cele działań w strefie oraz efekty projektu: inderdyscyplinarne, ponadregionalne, metodologiczne.
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E-Beam Effects on Poly(Xylitol Dicarboxylate-co-diol Dicarboxylate) Elastomers Tailored by Adjusting Monomer Chain Length
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Glass transition temperatures of polyurethane-urea elastomers based on N, N′-ethylenethiourea and N, N′-ethyleneurea as chain extenders
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The suitability of DNA extracted from formalin-fixed, paraffin-embedded tissues for double differential polymerase chain reaction analysis
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A New Era Is Beginning in Central and Eastern Europe: Information and Communication Technology Services Exceed Manufacturing in the Global Production Chain
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Construction of a simulation model of goods delivery in international road transportation taking into account the functioning efficiency of logistics supply chain
PublicationThe object of this study is the process of goods delivery in international road transport using various types of logistics chains. The problem being solved is due to the need to develop recommendations for exporters of goods to reformat or design new supply chains during wartime. The expediency of organizing foreign trade operations by the cargo owners' own forces or with the involvement of enterprises providing logistics consulting...
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Estimation of the steam condensation flow via CFD methods
PublicationThe results of numerical simulations to predict the performance of different steam models have been presented. All of the considered models of steam condensation have been validated on the base of benchmark experiment employing expansion in nozzle and next on the low pressure part of the steam turbine stage. For numerical analysis three models have been finally used – the ideal steam model without condensation, an equilibrium steam...
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Tests of a Steam Piston Engine Under Supercritical Conditions
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Application of gas-steam mixture for wood drying purposes
PublicationW artykule przedstawiono wyniki suszenia drewna przy zastosowaniu mieszaniny parowo-gazowej. Badania dotyczyły suszenia drewna dębowego, sosnowego i świerkowego. We wszystkich eksperymentach skrócono czas suszenia w porównaniu z suszeniem konwencjonalnym.
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Corrosion of evaporator tubes in low emission steam boilers
PublicationPurpose of this paper is to reveal the mechanisms of corrosion processes of outer surfaces of low-emission steam boiler evaporator tubes. Examinations were performed to find the reasons of different corrosion susceptibility of tubes situated at combustion chamber on various levels. Examinations were conducted on several segments of 57 x 5.0 mm evaporator tubes made of 16M (16Mo3) steel grade. Segments were taken from level of...
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Enhancement of the Brayton cycle efficiency by water or steam utilization
PublicationIn the paper, thermodynamic analysis of two modifications of a Brayton cycle into enhancement cycles with water/steam injection are discussed. The first one deals with a STIG modified system with both interstage compressed air cooling and air heating (heat regeneration) before combustion chamber. The second one, mainly devoted to higher steam/air ratio, is connected with separate steam production in a HRSG. The analysis has been...
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Influence of steam drying process on wood mechanical properties
PublicationResults of influence of gas-steam mixture drying process on mechanical properties of material 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 in a laboratory kiln especially arranged for that reason. Measurements of the global coefficient of elasticity and bending strength...
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Dynamic model of nuclear power plant steam turbine
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Kinetic analysis of the stage for a high speed steam turbine
PublicationThis article analyzes possibilites of resonances within a control stage for a high speed steam turbine. This stage hase been based on assembling of a single blade to a rotating disk and increasing of rigidity of the system by using of a bandage. In the analysis will be nd a possiblity of resonance frequency, and mistuning by showing safety working ranges. The calculations have bean used the3D modal and harmonic analysis by the...
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Steam turbines governors in power system restoration process
PublicationThe 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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Hydrodynamic journal bearing - ''Y'' particularly for steam turbines.
PublicationW artykule przedstawiono koncepcję i zasadę działania nowego, ślizgoweo łożyska poprzecznego typu ''Y''. Przedstawiono wady i zalety nowego rozwiązania. Porównano charakterystyki dynamiczne i statyczne klasycznego łożyska cytrynowego (soczewkowego) z nowym łożyskiem ''Y''.Podano przykładowe wdrożenia i ich efekty.
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Modeling of entrained flow steam gasification of sewage sludge
PublicationProper management of sewage sludge becomes increasingly problematic due to legal requirements aiming at diminishing environmental impact, as well as rationalizing the utilization from the point of view of logistics. Steam gasification of sewage sludge can result in very good quality of the producer gas. So far, the works have been focused on the gasification in fixed bed gasifiers. However, this does not allow to take full advantage...
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INFLUENCE OF INLET GEOMETRY ON THE EFFICIENCY OF 1MW STEAM TURBINE
PublicationThe process of the design of the 1MW steam turbine includes designing the stator and rotor blades, the steam turbine inlet and exit, the casing and the rotor. A turbine that operates at rotation speeds other than 3000 rpm requires a gear box and generator with complex electronic software. This paper analyses the efficiency of eight turbine variants, including seven inlet geometries and three stages of stator as well as an eight...
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Szara strefa jako jeden ze skutków określonej polityki podatkowej państwa
PublicationSkutki szarej strefy są wielopłaszczyznowe i dotykają praktycznie wszystkich dziedzin gospodarki oraz życia społeczeństwa. Jednym z podstawowych czynników wpływających na rozwój szarej strefy gospodarczej jest nieakceptowalny system podatkowy. Badania i estymacje pozwalają na oszacowanie podatkowych skutków szarej strefy gospodarczej w Polsce w przedziale od 84,8 mld zł do 145 mld zł. W celu eliminowania podatkowych uwarunkowań...
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Bacterial Pathogens in the Food Industry: Antibiotic Resistance and Virulence Factors of Salmonella enterica Strains Isolated from Food Chain Links
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Improvement of the Treatment of Loop Structures in the UNRES Force Field by Inclusion of Coupling between Backbone- and Side-Chain-Local Conformational States
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The Influence of Alkyl Chain Length and Steric Effect on the Stability Constants and Extractability of Co(II) Complexes with 1-Alkyl-2-Methylimidazoles
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Enhancing chain-elongating microbiomes: Sequential fungi-bacteria cooperation for efficient food waste upgrading using endogenous electron donors
PublicationThe upgrading of organic waste such as food waste (FW) into medium-chain carboxylates (MCC) is within a bio-based circular economy concept. An efficient chain elongation (CE) microbiome is difficult to obtain, which normally requires long-term acclimatization and an exogenous supplement of electron donor (ED, especially ethanol). In this study, the CE microbiome was rapidly shaped within 18 days and an efficient endogenous ethanol-based...
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The innovative experimental rig for wood steam drying at atmospheric pressure
PublicationThe 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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Application of Artificial Neural Networks in Investigations of Steam Turbine Cascades
PublicationZaprezentowano wyniki badań numerycznych zastosowania sieci neuronowych przy obliczeniach przepływów w palisadach turbin parowych. Na podstawie uzyskanych wyników wykazano, że sieci neuronowe mogą być używane do szacowania przestrzennego rozkładu parametrów przepływu, takich jak entalpia, entropia, ciśnienie czy prędkość czynnika w kanale przepływowym. Omówiono również zastosowania tego typu metod przy projektowaniu palisad, stopni...
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Static Model of Steam/Water Cycle for Thermal and Economic Analysis
PublicationThe thermodynamic efficiency of typical conventional and nuclear power plants is insufficient. A large amount of the generated heat is removed to the environment and regarded as a waste. A solution which is commonly used to increase the efficiency and profitability of the existing and planned power plants refers to cogeneration of heat and power. To prepare sophisticated thermodynamic and economic analyses, a precise static model...
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Analysis of unsteady flow forces on the thermowell of steam temperature sensor
PublicationIn this paper, 3D numerical analysis of unsteady flow forces acting on the measuring sheath of steam temperature is presented. According to that purpose, the CFD (Computation Fluid Dynamic [1]) approach has been used. The nonstationary of fluid acting on the measuring sheath such as: Strouhal frequency, amplitude of pressure, structure of vortex, peak of pressure, field of pressure, field of velocity etc. are studied analytically...
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Assessment of evaporator tubes corrosion in low-emission steam boilers
PublicationW artykule przedstawiono wyniki badań rur ekranowych(16Mo3) kotła niskoemisyjnego po jednym roku i dwóch latach eksploatacji. Powierzchnie rur pokryte zostały warstwami natryskiwanymi cieplne - pojedynczą ze stopu 70%Ni 30%Cr i podwójną Ni-30Cr /Al2O3. Rury bez powłok natryskiwanych wykazywały pocienienie ze względu na działanie korozji siarkowej oraz korozyjnego oddziaływania warstwy stopionych soli. Pojedyncza warstwa 70%Ni 30%Cr...
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Possibilities of Increasing the Overall Efficiency of Gas-steam CHP Microplant
PublicationThe paper presents ways to increase the efficiency of a gas-steam micro power plant by modifying the cycle combination. The modification consists in partial release of the fluid downstream of the gas turbine and using it for ORC fluid overheating and evaporation. Advantages of this solution over the simplest gas and steam cycles’ combination are demonstrated.
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Experimental research on marine oil-lubricated stern tube bearing
PublicationBearings of propeller shafts are very crucial elements of the propulsion system of each of the ships. The safety of shipping depends on their durability and reliability. The new legal restrictions mean that today we are looking for environmentally friendly solutions. That is why water-lubricated bearings are becoming more and more popular. So, will oil-lubricated shaft bearings belong to the past? The bearing with a white metal...
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The thermal effort during marine steam turbine flooding with water
PublicationThe work discussed an extreme case of cooling a steam turbine. The ship's steam turbine was used as an example. In marine transport units with low-speed engines dominate, however, there are also units with steam turbines. An example of analysed marine steam turbine is shown in Fig. 1. When considering the issue of cooling steam turbines, it is necessary to estimate the extreme conditions that may occur during operation of the turbine....
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Selected Problems of Experimental Testing Marine Stern Tube Bearings
PublicationThis paper presents typical methods for conducting experimental tests on main shaft slide bearings. There are described their possible testing capabilities, advantages, drawbacks and limitations. Various testing methods were analyzed to find a solution able of providing a wide range of possible investigations at possibly acceptable limitations.
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ENHANCED MASTER CYCLE - SIGNIFICANT IMPROVEMENT OF STEAM RANKINE CYCLE
PublicationThe present paper focuses on an enhancement of the Master Cycle. In the first part, the paper presents a classical Master Cycle which is a modification of the double reheat Rankine cycle. This modification allows to slightly increase efficiency, resolves problems caused by superheated steam on bleeds and decreases mass flow rate of steam directed to reheat. These improvements include the implementation of a tuning turbine from...
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Technical and Economic Analysis of the Supercritical Combined Gas-Steam Cycle
PublicationCombined cycle power plants are characterized by high efficiency, now exceeding 60%. The record-breaking power plant listed in the Guinness Book of World Records is the Nishi-Nagoya power plant commissioned in March 2018, located in Japan, and reaching the gross efficiency of 63.08%. Research and development centers, energy companies, and scientific institutions are taking various actions to increase this efficiency. Both the gas...
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The effect of alkyl chain length on synergistic effects in micellization and surface tension reduction in nonionic gemini (S-10) and anionic surfactants mixtures
PublicationMixtures of nonionic gemini surfactant S-10 ( α, α'-[2,4,7,9-tetrametyl-5-decyne-4,7-diyl]bis[ω-hydroxy -polioxyetylene] with anionic SRS (sodium alkylsulfates) and SRSO3 (sodium alkylsulfonates) of different alkyl chain length (from 10 to 14 carbon atoms) were investigated. Surface tension measurements were used to find the cmc values and other adsorption parameters. The Clint, Rubingh’s and Rosen theories were applied for evaluation...
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Synthesis of oxathiolone fused chalkones bearing O-aminoalkyl side chain. Comparison of stability of isomeric benzoxathiolones under alkylation reaction conditions
PublicationIzomeryczne oksatiolonowe sprzężone chalkony zawierające O-alkilowe łańcuchy boczne otrzymano w wyniku kondensacji odpowiednich benzoksatiolonów z podstawionymi benzaldehydami. Wyjściowe benzoksatiolony otrzymano w wyniku alkilowania odpowiednich fenoli chlorkami aninoalkilowymi, jednakże reakcja była często komplikowana w wyniku otwarcia pierścienia oksatiolonowego poprzez grupę aminową. Określono aktywność cytotoksyczną i przeciwdrobnoustrojową...
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Striking influence of chain structure of polyethylene on the formation of cup-stacked carbon nanotubes/carbon nanofibers under the combined catalysis of CuBr and NiO
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Forum morskie i strefa rozwoju centrum miasta - nowa morska brama Gdyni?
PublicationRolą tego artykułu jest pokazanie związków funkcjonalno-przestrzennych Gdyni z morzem. Przedstawiono w nim możliwości przekształcenia terenów poportowych i poprzemysłowych przylegających do historycznego centrum. Tereny te odgrywają ważną rolę w przekształceniach struktur miejskich prowadzących do odnowy krajobrazu miasta. W Gdyni stwarzają one szansę na rozwój nowoczesnego śródmieścia, którego miastu brakuje, a także otwarcia...
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Wartość dodana realizacji Projektu Łuk Południowego Bałtyku - Strefa Rozwojowa Południowego Bałtyku.
PublicationWartość dodana (added value) jest nowym pojęciem w ocenie rozwoju regionalnego i w pracy zostało zdefiniowane. Oceniono efekty projektu w strefie regulacji i efekty metodologiczne. Zrealizowano efekty partnerskie i przywództwa w tworzeniu i realizacji wielkich projektóww przestrzennych.
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On the possible increasing of efficiency of ship power plant with the system combined of marine diesel engine, gas turbine and steam turbine at the main engine - steam turbine mode of cooperation
PublicationW pracy przedstawiono koncepcję układu kombinowanego okrętowego dużej mocy złożonego z silnika głównego tłokowego oraz skojarzonych z nim turbiny gazowej mocy i układu turbiny parowej, wykorzystujących energię zawartą w spalinach wylotowych silnika głównego tłokowego. Rozpatrywano układ kombinowany układ złożony z silnika spalinowego tłokowego skojarzony z układem turbiny parowej. Podano algorytm i obliczenia poszczególnych podukładów:...
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Bezpieczeństwo transportu drogowego: Stan bezpieczeństwa
PublicationCharakterystyka ogólna wypadków drogowych, czynnik ludzki w wypadkach drogowych, Infrastruktura drogowa i jej otoczenie, Cechy pojazdów drogowych.
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Dziedzictwo kulturowe - stan i zasoby
PublicationPublikacja omawia zasoby dziedzictwa kulturowego Gdyni, rozpatrując je w dwóch głównych grupach: pierwszej, dotyczącej modernistycznych zespołów architektoniczno-urbanistycznych z okresu dwudziestolecia międzywojennego i drugiej, obejmującej zespoły osadnictwa przedmiejskiego. Opracowanie wymienia także zdegradowane przestrzennie tereny miejskie, przedmiejskie i dworsko-parkowe o dużym potencjale historycznym,a także zespoły fortyfikacyjne...
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Stan graniczny montażu konstrukcji stalowych.
PublicationW referacie przedstawiono probabilistyczną definicję tolerancji a następnie zdefiniowano pojęcie stanu granicznego montażu. Określono obszar montażu bezpiecznego, niezawodnego oraz awaryjnego. Przedstawiono graficzną ilustrację zagadnienia na przykładzie liniowej funkcji pętli montażowej. Przedyskutowano wpływ wartości odchylenia standardowego na wymiary obszaru niezawodnego montażu. Opisano sposób wykorzystania pojęcia indeksu...
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An asymmetrical λ-foot of condensing steam flow in the IMP PAN nozzle
PublicationIn 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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Selected thermal and flow issues in a reversed thermosiphon with a steam liquid lifter
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