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Limited selectivity of amperometric gas sensors operating in multicomponent gas mixtures and methods of selectivity improvement
PublicationIn recent years, smog and poor air quality have became a growing environmental problem. There is a need to continuously monitor the quality of the air. The lack of selectivity is one of the most important problems limiting the use of gas sensors for this purpose. In this study, the selectivity of six amperometric gas sensors is investigated. First, the sensors were calibrated in order to find a correlation between the concentration...
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Influence of gas parameters alteration on the form of gas-flow-impact appearing in long transportation pipelines
PublicationPrzy szybkich zamknięciach przepływu w długich liniach transportowych gazu, obserwuje się znaczne przesterowania ciśnienia, towarzyszące zjawiskom udarowym, wywołane zarówno falą uderzeniową jak i odbitą. Głównym czynnikiem wpływającym na postać fali uderzeniowej i jej amplitudy, jest szybkość zamykania zaworu odcinającego określona stałą czasową serwomotoru sterującego zaworem. Ponieważ obserwuje się zmiany właściwości chemicznych...
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Energy requirements for methods improving gas detection by modulating physical properties of resistive gas sensors
PublicationAbstract. One of the most important disadvantage of resistive gas sensors is their limited gas selectivity. Therefore, various methods modulating their physical properties are used to improve gas detection. These methods are usually limited to temperature modulation or UV light irradiation for the layers exhibiting photocatalytic effect. These methods cause increased energy consumption. In our study we consider how much energy...
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International Journal of Oil Gas and Coal Technology
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Portable exhaled breath analyzer employing fluctuation-enhanced gas sensing method in resistive gas sensors
PublicationThis paper presents a portable exhaled breath analyser, developed to detect selected diseases. The set-up employs resistive gas sensors: commercial MEMS sensors and prototype gas sensors made of WO3 gas sensing layers doped with various metal ingredients. The set-up can modulate the gas sensors by applying UV light to induce physical changes of the gas sensing layers. The sensors are placed in a tiny gas chamber of a volume...
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Jolanta Tomaszewska-Gras dr hab.
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Electrocatalytic gas sensor response analysis
PublicationW pracy przedstawiono i porównano metody analizy odpowiedzi elektrokatalitycznych czujników gazów toksycznych. Opisane metody pozwalają na ekstrakcje z odpowiediz czujników informacji o rodzaju gazu oraz o jego stężeniu.
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Gas-steam mixture wood drying
PublicationBadania skuteczności suszenia wysokotemperaturowego suszenia drewna w komorze suszarniczej - wstępne wyniki.
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Materials for potentiometric electrochemical gas sensors
PublicationPublikacja przeglądowa na temat zasady działania oraz rodzajów czujników elektrochemicznych gazów.
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Fluctuation phenomena in semiconductor gas sensors
PublicationCzujniki gazu mogą być wytwarzane z cienkiej warstwy półprzewodnika, która po podgrzaniu do odpowiedniej temperatury staje się czuła na gaz. Zjawisko to jest dobrze znane i szeroko opisane w literaturze. Jako wskaźnik detekcji gazu wykorzystuje się zmianę rezystancji stałoprądowej czujnika. Zwiększenie czułości i, co najważniejsze z praktycznego punktu widzenia, selektywności dyskryminacji można uzyskać jeśli warstwa półprzewodnika...
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Tools for signal analysis of gas sensors
PublicationStatystyki drugiego rzedu oraz jklasyczna analiza widmowa są zwykle stosowane do badania sygnałów losowych o rozkładzie gaussowskim. Są one jednak często nieodpowiednie w przypadku analizy niestacjonarnych sygnałów niegaussowskich. Pewne narzędzia do analizy takich sygnałów sa dostępne w bibliotekach środowiska MATLAB. Zostały one wykorzystane do do analizy fluktuacji sygnałów czujników gazów. W artykule przedstawiono system do...
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Transportable, Portable and Micro Gas Chromatographs
PublicationSignificant benefits can be obtained by miniaturization of conventional benchtop gas chromatographs. The attractive features arising from miniaturization include low-power requirements, low heat capacity of separation columns, low consumption of mobile phase, enhanced performance, higher portability, and easily coupling to detectors and secondary chromatographic systems. In separation sciences, including gas phase separations,...
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On the selectivity of nanostructured semiconductor gas sensors
Publication.
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Devices for the production of reference gas mixtures
PublicationFor many years there has been growing demand for gaseous reference materials, which is connected with development in many fields of science and technology. As a result, new methodological and instrumental solutions appear that can be used for this purpose. Appropriate quality assurance/quality control (QA/QC) must be used to make sure that measurement data are a reliable source of information. Reference materials are a significant...
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Gas sensors based on superionic conductors
PublicationW pracy przedstawiono przegląd rozwiązań elektrochemicznych czujników gazów na bazie elektrolitów stałych.
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Electrocatalytic gas sensor with reference layer
PublicationIn recent years electrochemical gas sensors based on solid state electrolytes have been intensively developed. They are easy to obtain, use and relative durable. Nasicon is one of the most promising materials, which have been used in construction of gas sensors. Most of these devices work in potentiometric or amperometric mode. However, some works are dedicated to sensors working in electrocatalytic mode. Principle of operation...
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GAS SENSORS WITH TEMPERATURE MODULATION – AN OVERVIEW
PublicationAlthough different methods of improving semiconductor gas sensor properties have been proposed, a technique involving temperature modulation seems to be the most promising. Semiconductor gas sensors working with modulated temperature can be more stable and are more selective comparing with sensor working at one temperature. In this paper, various approaches to temperature modulation are reviewed.
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Perforating systems in shale gas recovery
PublicationHydraulic fracturing is common method of shale gas recovery. Due to environmental, economical and technological problems many alternative technologies have been developed. One of the most promising group of technologies is based on perforating systems. This paper describes theoretical and practical aspects of best known technologies used to create perforations. New perforating/fracturing technologies which can replace hydraulic fracturing...
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Noise related to gas bottles explosions
PublicationModern industrialized world is in a never ending danger of accidents and catastrophes of technical nature. Some of them may involve fires and explosions of gas storage bottles or containers. Technical University of Gdansk, Poland performed numerous tests where bottles containing acetylene, oxygen, hydrogen, CO2, LPG, LNG or CNG were blown due to excessive temperature caused by fire. Although those experiments were not focused on...
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Quantum dots in gas sensing a review
PublicationAir pollution becomes an increasing problem in the recent years. There is a need to develop more sensitive gas sensors. Much effort has been performed to develop different types of gas sensors, such as electrochemical sensors or polymer sensors. One of the most promising approaches to improve sensors performance is the application of the nanostructures as sensing materials. State of the art of quantum...
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Hydrogen sulphide electrocatalytic gas sensor
PublicationIn this article measurement results of the electrocatalytic gas sensor in different concentrations of hydrogen sulphide are presented. Working principle of such sensor is based on electric current acquisition, while voltage ramp is applied to the sensor. During voltage sweep oxidation and reduction reactions occurs on the sensor electrodes. Obtained current-voltage plot has unique shape connected...
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Gas chromatography-olfactometry of alcoholic beverages
PublicationW rozdziale 5 książki przedstawiono zastosowanie techniki chromatografia gazowa-olfaktometria (GC-O)w ustalaniu zależności między zapachem a składem chemicznym lotnej frakcji napojów alkoholowych. W pierwszej części przedstawiono zasadę techniki GC-O, procedury przygotowania próbek do analizy, metody zbierania danych oraz warunki analizy. Następnie omówiono zastosowanie techniki GC-O w analizie i ocenie jakości różnych napojów...
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Electrocatalytic Gas Sensor with Reference Layer
PublicationThis paper presents studies of gas sensors prepared in ceramic technology with Nasicon as a solid electrolyte. Sensors work in the voltammetric mode thus based on the excitation of a sensor with a periodic potential signal while current response is recorded. The main aim is to investigate a Bi8Nb2O17 reference layer influence on sensor properties. Sensors I-V characteristics in different concentration of nitrogen dioxide have been...
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Hydraulic impact in a long gas-pipelines
PublicationPrzedstawiono model hydraulicznej linii długiej rurociągu gazowego. Obliczenia numeryczne dotyczą procesów dynamicznych w rurociągu gazowym przy nagłym zamknięciu zaworu na końcu rurociągu. Badano wpływ współczynnika izentropy przesyłanego gazu na wielkość uderzenia hydraulicznego oraz wpływ inercyjności zaworu na możliwość łagodzenia uderzenia hydraulicznego.
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Solid-state electrochemical gas sensors
PublicationW pracy przedstawiono budowę i zasadę działania wybranych typów elektrochemicznych czujników gazów zbudowanych na bazie elektrolitów stałych.
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Gas turbine: advanced marine propulsion.
PublicationPrzedstawiono rys historyczny rozwoju okrętowych turbin gazowych. Omówiono główne problemy zastosowania turbiny gazowej jako głównego silnika okrętowego i współczesne tendencje rozwoju tego napędu.
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Exhaust gas temperature measurements in diagnostic examination of naval gas turbine engines. Part II. Unsteady processes
PublicationThe second part of the article presents the results of operating diagnostic tests of a two- and three-shaft engine with a separate power turbine during the start-up and acceleration of the rotor units. Attention was paid to key importance of the correctness of operation of the automatic engine load control system, the input for which, among other signals, is the rate of increase of the exhaust gas flow temperature. The article...
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Fluctuation enhanced gas sensing with WO3-based nanoparticle gas sensors modulated by UV light at selected wavelengths
PublicationThe sensitivity and selectivity of WO3-based gas sensors can be enhanced by UV-irradiation-induced modulation, especially if different wavelengths are employed. We used fluctuation-enhanced gas sensing, based on measurements of resistance fluctuations in the gas sensor, to study the effects of such modulation on the noise intensity for ambient atmospheres of synthetic air without and with additions of small amounts of ethanol,...
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GaAs ballistic and tunneling nanodevices for terahertz electronics and medical applications
PublicationPrzy użyciu selektywnej epitaksji warstw molekularnych (MLE) wytworzono w GaAs balistyczne i tunelowe tranzystory o indukcji elektrostatycznej (SIT), z kanałami w skali 10 nm. Szacowany czas przelotu elektronów jest krótszy od 2×10-14 s. Metoda MLE została również wykorzystana do wykonania diod generacyjnych TUNNETT działających w oparciu o czas przelotu i tunelowe wstrzykiwanie elektronów. Z użyciem diod TUNNETT wygenerowano częstotliwość...
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Thermal performance of Si and GaAs based solar cells and modules.
PublicationPraca przedstawia aktualny stan wiedzy na temat wpływu temperatury na parametry pracy ogniw i modułów fotowoltaicznych z amorficznego krzemu i GaAs. Przedstawiono ogólna analizę rezultatów zastosowania modułów fotowoltaicznych w budownictwie ze szczególnym uwzględnieniem systemów hybrydowych, przekształcających energie słoneczną w prąd elektryczny i ciepło.
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A comparative study of pentanol (C5 alcohol) and kerosene blends in terms of gas turbine engine performance and exhaust gas emission
PublicationThe growing demand for sustainable and clean energy sources provides the incentive for the development of alternative fuels. Simultaneously, the development of gas turbine technologies with flexible fuel supply systems enables the use of alternative non-fossil fuels that can play key roles in contributing to global efforts in meeting emissions targets. This paper presents the current state of knowledge on the production and potential...
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Exhaust gas temperature measurements in diagnostic examination of naval gas turbine engines. Part I: Steady-state processes
PublicationThe article presents a possible method of detecting failures in the flow section and supply system of a naval gas turbine engine based on the exhaust gas temperature measured behind the gas generator. This temperature is a basic diagnostic parameter use for evaluating the technical state of the turbine engine in operation, and is monitored during engine start-ups, accelerations and decelerations of rotor units, and steady-load...
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Exhaust gas temperature measurements in diagnostic examination of naval gas turbine engines. Part III. Diagnostic and operating tolerances
PublicationThe third part of the article presents a method for detecting failures of the automatic engine control system with the aid of an exhaust gas temperature setter, specially designed and machined for this purpose. It also presents a procedure of identifying the operating tolerances and determining the diagnostic tolerances for the exhaust gas temperature recorded in the naval turbine engine during the start-up and acceleration processes....
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Real-time working gas recognition system based on the array of semiconductor gas sensors and portable computer Raspberry PI
PublicationThe gas-analyzing systems based on the array of partially selective gas sensors and pattern-recognition techniques are potentially fast and low-cost alternative for other devices, like gas analysers. They give the possibility of recognition the type and the concentration of measured volatile compounds in their working environment. In this work we present the implementation of gas recognition system, in which the signals from an...
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Chromatographic Examinations in the Gas Network Odourised by Tetrahydrothiophene
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Roadmap on dynamics of molecules and clusters in the gas phase
PublicationThis roadmap article highlights recent advances, challenges and future prospects in studies of the dynamics of molecules and clusters in the gas phase. It comprises nineteen contributions by scientists with leading expertise in complementary experimental and theoretical techniques to probe the dynamics on timescales spanning twenty orders of magnitudes, from attoseconds to minutes and beyond, and for systems ranging in complexity...
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Exhaled breath analysis by resistive gas sensors
PublicationBreath analysis has attracted human beings for centuries. It was one of the simplest methods to detect various diseases by using human smell sense only. Advances in technology enable to use more reliable and standardized methods, based on different gas sensing systems. Breath analysis requires the detection of volatile organic compounds (VOCs) of the concentrations below individual ppm (parts per million). Therefore, advanced detection...
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Dissociative ionization dynamics of dielectric gas C3F7CN
PublicationFluoronitrile C3F7CN is a promising candidate for the replacement of SF6 dielectric gas in high-voltage insulation. We present a combined experimental and theoretical study on its ionization dynamics probed in the 0-100 eV energy range. We exploited the total ion collection technique to determine the absolute ionization cross section, mass spectrometry to determine the fragment branching ratios and ab initio nonadiabatic molecular...
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Application of ionic liquids for gas separation processes
PublicationNowym kierunkiem w procesach separacji dwutlenku węgla stało się w ostatnich latach zastosowanie cieczy jonowych. Niemierzalna prężność par i możliwość dostosowania ich właściwości czyni je idealnymi mediami zastępującymi lotne, korozyjne i toksyczne rozpuszczalniki. Ponadto ciecze jonowe wykazują niską współabsorpcję innych gazów. Dlatego też, możliwe jest selektywne odseparowanie dwutlenku węgla z mieszanin gazowych
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Gas sensors based on functionalized carbon nanotubes
PublicationW pracy przedstawiono przegląd czujników gazów z modyfikowanych nanorurek węglowych.
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Security Assessment of a Turbo-Gas Power Plant
PublicationCritical infrastructures are exposed to new threats due to the large number of vulnerabilities and architectural weaknesses introduced by the extensive use of information and communication technologies. This paper presents the results of an exhaustive security assessment for a turbo-gas power plant.
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Staircase Voltammetry Application to Electrocatalytic Gas Sensor
PublicationW pracy przedstawiono wyniki badań czujnika elektrokatalicznego pobudzanego sygnałem schodkowym w różnych mieszaninach gazowych .
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Shooting Gas Cylinders to Prevent Their Explosion in Fire
PublicationGas cylinders in general, and particularly cylinders containing acetylene, constitute a great potential danger to fire and rescue services involved in salvage operations. Experiments show that gas cylinders with acetylene, oxygen, hydrogen, CNG, LPG or CO2 may blow after short exposition to heat with very destructive effect as fragments of blown cylinder may fly even several hundred meters. In the case of acetylene the explosion...
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Magnetoacoustic heating in a quasi-isentropic magnetic gas
PublicationThe nonlinear heating of a plasma which associates with the transfer of energy of magnetoacoustic waves into that of the entropy mode, is analytically studied. A plasma is uniform and motionless at equilibrium. Perturbations in a plasma are described by a system of ideal magnetohydrodynamic equations. The equilibrium straight magnetic strength and the wave vector form a constant angle which varies from 0 to π/2. There exist four...
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Polypyrrole based gas sensor for ammonia detection
PublicationThe nature of polypyrrole response to toxic gases does not allow using the sensor in a conventional way. The main aim of this study is to acquire the information about the concentration using different approaches: a linear approximation, a non-linear approximation and a tangent method. In this paper a two-steps procedure for sensor response measurements has been utilized. Polypyrrole films were electrochemically synthesized on...
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Application of Ionic Liquids in Amperometric Gas Sensors
PublicationThis article presents an analysis of available literature data on metrological parameters of the amperometric gas sensors containing ionic liquids as an electrolyte. Four mechanism types of signal generation in amperometric sensors with ionic liquid are described. Moreover, this article describes the influence of selected physico-chemical properties of the ionic liquids on the metrological parameters of these sensors. Some metrological...
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An electronic nose for quantitative determination of gas concentrations
PublicationThe practical application of human nose for fragrance recognition is severely limited by the fact that our sense of smell is subjective and gets tired easily. Consequen tly, there is considerable need for an instrument that can be a substitution of the human sense of smell. Electronic nose devices from the mid 1980s are used in growing number of applications. They comprise an array of several electrochemical gas sensors...
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Dopants and gas modifiers in ion mobility spectrometry
PublicationThe ion mobility techniques, including the most commonly used drift-tube ion mobility spectrometry (IMS) and differential mobility spectrometry (DMS), are used successfully for the detection of a wide range of organic compounds in the gas phase. In order to improve detection quality, admixtures are added to gas streams flowing through the detector. Dopants mostly prevent the ionization of interfering chemicals however, better detection...
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Microscopic parameters of gas via acoustic measurements
PublicationProponujemy wstępną analizę odwrotnego problemu, który sformułowano, opartą na statycznej mechanice /termodynamice, rozważającej gaz jako środek rozprzestrzeniania dzwięku.
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Electrocatalytic gas sensors based on Nasicon and Lisicon
PublicationW pracy przedstawiono porównanie właściwości czujników elektrokatalitycznych na bazie Nasiconu i Lisiconu. Czujniki zostały przygotowane w technologii ceramicznej. Przedstawiono wyniki badań czujników w obecności mieszaniny dwutlenku azotu, dwutlenku siarki i syntetycznego powietrza.