Wyniki wyszukiwania dla: GAS DETECTION
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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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Spinning Fluids Reactor: A new design of a gas – liquid contactor
PublikacjaCurrent trends in chemical reactor design are based on adapting these to the requirements of a particular chemical process. Processes involving reactions between the gas and liquid phase in particular require precise adjustment of all parameters. The common denominator for most modern design solutions is enhancement of the mass transfer area and the overall volumetric mass transfer coefficient. Gas – liquid contactors evolved from...
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Two-dimensional gas chromatography – principles and application in fruits analysis
PublikacjaTwo-dimensional gas chromatography is a rapidly developing analytical technique. One of the major uses of this technique is its use for food analysis. The paper presents the principle of operation and history of this analytical technique. The specification of the two-dimensional gas chromatography technique has been discussed. The principles of separation of ingredients and application of the method, particularly in the analysis...
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Nonlinear phenomena of small-scale sound in a gas with exponential stratification
PublikacjaThe nonlinear dynamics of perturbations, quickly varying in space, with comparatively large characteristic wavenumbers k: k>1/H, is considered. H is the scale of density and pressure reduction in unperturbed gas, as the coordinate (H is the so-called height of the uniform equilibrium gas). Coupling nonlinear equations which govern the sound and the entropy mode in a weakly nonlinear flow are derived. They describe the dynamics...
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Gas turbines – technological development and potential use in CAES systems
PublikacjaThis article briefly describes Compressed Air Energy Storage (CAES), focusing on the technological development of one of the key elements of such systems – the gas turbines. It presents the basic parameters and features of gas turbines, as well as turbine classes with example models. Main tendencies in the structural and technological development are discussed. Changes and trends on electric energy markets are becoming more and...
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The Application of Open Capillary Modules for Sweeping Gas Membrane Distillation
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Investigation of the temperature modulation parameters on semiconductor gas sensor response
PublikacjaIn this work we present the results of the investigation of the sensing properties of semiconductor gas sensors with a sinusoidally modulated temperature in the presence of synthetic air (SA) and three volatile air pollutants, i.e. NH3, NO2 and SO2. The measurements were performed for different average sensor heater temperatures and the amplitude of the modulation signal. In addition, the extraction of features from the sensor...
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Technical and Economic Analysis of the Supercritical Combined Gas-Steam Cycle
PublikacjaCombined 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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Development of Gas Sensor Array for Methane Reforming Process Monitoring
PublikacjaThe article presents a new method of monitoring and assessing the course of the dry methane reforming process with the use of a gas sensor array. Nine commercially available TGS chemical gas sensors were used to construct the array (seven metal oxide sensors and two electrochemical ones). Principal Component Regression (PCR) was used as a calibration method. The developed PCR models were used to determine the quantitative parameters...
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Analysis and interpretation of radiometric signals in a liquid-gas bubble flow
PublikacjaThe article presents the analysis of signals from a radiometric system consisting of two scintillation probes and two gamma radiation sealed sources. Calculations and interpretation were carried out for the bubble flow of the water-air mixture in the horizontal pipeline. The analysis of the obtained signals was done in time and frequency domain. In the frequency domain, a range of usable frequencies was identified, which were associated...
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Low-energy positron scattering from gas-phase benzene
PublikacjaIn this paper we are presenting calculations of the elastic cross section of positrons with gas-phase benzene for the energy range from 0.25 eV to 9.0 eV. The calculations are done with the molecular R-matrix method for positron-scattering from poly-atomic molecules using a scaling factor to scale the electron-positron interaction. The scaling factor influences the position of the poles of the R-matrix. We adjust the scaling factor...
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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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Gas turbine as ship prime mover - specific problems and prospects.
PublikacjaPrzedstawiono ewentualne możliwości zastosowania turbin gazowych w okrętownictwie. Analizowano aspekty ekologiczne, ekonomiczne i techniczne.
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Resistance Noise Higher-Order Spectrums in Nanoparticle Gas Sensors.
PublikacjaPrzedstawiono badania fluktuacji rezystancji sensora gazu wykonanego z nanocząstek WO3. Stwierdzono występowanie składowych o rozkładzie prawdopodobieństwa różnym od rozkładu Gaussa. W celu zwiększenia czułości i selektywności wykrywanych gazów zastosowan do analizy obserwowanych fluktuacji spektra wyższych rzędów.
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Gas sensing by thermoelectric voltage fluctuations in SnO2 nanoparticle films
PublikacjaPrzedstawiono eksperymentalne wyniki wykrywania gazów za pomocą badania fluktuacji napięcia termoelektrycznego w warstwie SnO2 przygotowanej z jednorodnych ziaren o średnicy 20 nm. Obserwowano fluktuacje napięcia bez zewnętrznej polaryzacji warstwy SnO2. Intensywność obserwowanych fluktuacji przekraczała 1000-krotnie intensywność szumów termicznych. Obserwowane zjawisko może byc wykorzystane do zwiększenia czułości wykrywania...
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Simulations of behaviour of granular bodies using a lattice-gas automaton.
PublikacjaW artykule przedstawiono wyniki numerycznej analizy przepływu materiałów granulowanych podczas 3 różnych problemów: przepływu silosowego, przepływu kanałowego i tworzenia się nasypu. W modelu zaczerpniętym z teorii gazów przyjęto kolizje cząsteczek i dysypację energii. Wyniki porównano z doświadczeniami.
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A novel methodology for the enantiomeric resolution of methamphetamine, its precursors and intermediates by GC-MS
PublikacjaImpurity profiling and classification of abused drugs using chiral analytical techniques is of particular interest and importance because of the additional information obtained from this approach. When these methods are applied to the synthesis of illicitly used substances, they can supply valuable information about the conditions/chemicals used in the synthesis. In this study, simultaneous chiral separation of methylamphetamine,...
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Organic Vapor Sensing Mechanisms by Large-Area Graphene Back-Gated Field-Effect Transistors under UV Irradiation
PublikacjaThe gas sensing properties of graphene back-gated field-effect transistor (GFET) sensors toward acetonitrile, tetrahydrofuran, and chloroform vapors were investigated with the focus on unfolding possible gas detection mechanisms. The FET configuration of the sensor device enabled gate voltage tuning for enhanced measurements of changes in DC electrical characteristics. Electrical measurements were combined with a fluctuation-enhanced...
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Application of Headspace Solid-phase Microextraction with Poly(1-vinyl-3- Hexylimidazolium Chloride) Polymeric Ionic Liquid Coating using GC - MS to Determine Volatile Fatty Acids in Dairy Wastewater
PublikacjaVolatile fatty acids were determined in this study using headspace solid-phase microextraction (HS-SPME) with a poly(1-vinyl-3-hexylimidazolium chloride) polymeric ionic liquid coated fiber followed by gas chromatography - mass spectrometry. Experimental parameters such as extraction time and temperature, sample volume as well as desorption time and temperature were optimized. Detection limits of the method were in the range of...
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Clinical studies of detecting COVID-19 from exhaled breath with electronic nose
PublikacjaThe COVID‑19 pandemic has attracted numerous research studies because of its impact on society and the economy. The pandemic has led to progress in the development of diagnostic methods, utilizing the polymerase chain reaction (PCR) as the gold standard for coronavirus SARS‑CoV‑2 detection. Numerous tests can be used at home within 15 min or so but of with lower accuracy than PCR. There is still a need for point‑of‑care tests available...
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Electrochemical investigations of stainless steels used in flue‐gas desulphurization units
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Non-matrix reference matrials- chalanges in the preparation of standard gas mixtures
PublikacjaIn the last few years particularly great pressure is exerted on quality control and assurance of analytical measurement results. An invaluable role in this process is played by reference materials. The paper presents the characteristics of basic types of reference materials, with particular attention to gaseous reference materials. In addition, a review of literature on techniques of preparation of gaseous standard materials, published...
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Procedure of determination of volatile trihalomethanes in human urine with perwaporation and gas chromatography
PublikacjaPraca przedstawia wyznaczanie podstawowych parametrów walidacyjnych nowej procedury oznaczania lotnych związków chlorowcoorganicznych z grupy trihalometanów w próbkach moczu ludzkiego, opartej na zastosowaniu:- techniki perwaporacji na etapie izolacji i wzbogacania analitów;- bezpośredniego dozowania próbek ekstraktów (permeatu) do kolumny chromatograficznej;- chromatograficznego rozdzielanie mieszaniny na poszczególne składniki;-wykorzystaniu...
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Modern techniques of sample preparation for determination of organic analytes by gas chromatography
PublikacjaW pracy dokonano przeglądu szerokiego spektrum technik przygotowania próbki, ze szczególnym uwzględnieniem technik o charakterze prośrodowiskowym. Opisu technik dokonano pod kątem wykorzystywanych mechanizmów izolacji analitów oraz stosowanych rozwiązań aparaturowych. Przegląd rozwiązań aparaturowych uzupełniono o podstawy teoretyczne izolacji bazującej na zjawisku podziału analitów.
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Accelerated solvent extraction-gas chromatographic determination of acidic herbicides in soil
PublikacjaPrzyspieszona ekstrakcja rozpuszczalnikiem z wykorzystaniem wody jako ekstraktanta okazała się skutecznym sposobem izolacji herbicydów kwasowych (MCPP, MCPA, 2,4-D, 2,4,5-T, PCP, dinoseb, dinoterb) z próbek gleby. Wysoka zawartość substancji iłowych powodowała problemy techniczne, które udało się pokonać poprzez zwiększenie stosunku piasku do gleby w celce ekstrakcyjnej. Anality przenoszono z ekstraktu wodnego do rozpuszczalnika...
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A procedure for the determination of dichloromethane and tetrachloroethene in water using pervaporation and gas chromatography
PublikacjaIn the present study, pervaporation was applied to the determination of tetrachloroethene (PCE) and dichloromethane (DCM) in liquid samples. PCE is the most commonly used solvent in dry-cleaning processes. PCE belongs to group 2A of carcinogens (probably carcinogenic to humans) according to the classification of the International Agency for Research on Cancer (IARC). DCM is also widely used as an industrial solvent for the purification...
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Non-matrix reference materials-the challenges in the preparation of standard gas mixtures
PublikacjaIn the last few years particularly great pressure is exerted on quality control and assurance of analytical measurement results. An invaluable role in this process is played by reference materials. The paper presents the characteristics of basic types of reference materials, with particular attention to gaseous reference materials.
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Liquid circulation in the agitated airlift reactor with the high gas disengagement zone
PublikacjaPrzedstawiono doświadczalne zależności stopnia zatrzymania gazu i prędkości cyrkulacji cieczy od prędkości przepływu gazu i częstości obrotów mieszadła. Obserwowano wzrost prędkości cyrkulacji cieczy ze wzrostem wysokości strefy napowietrzania. Dla niskich częstości obrotów mieszadła prędkość cyrkulacji cieczy wzrastała wraz ze wzrostem prędkości przepływu gazu, natomiast dla wysokich cząstości obrotów mieszadła prędkość cyrkulacji...
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Weakly nonlinear dynamics of short acoustic waves in exponentially stratified gas
PublikacjaRozpatruje się dynamika krótkich (w porównywaniu z charakterystyczną skalą zmiany gęstości gazu atmosferycznego) fal akustycznych. Wyprowadzone nowe równanie ewolucyjne, które uwzględnia dyspersję i nieliniowy charakter propagacji tych fal. Porównuje sie liniowa i nieliniowa dynamika. Ilustracje propagacji, numeryczne wyliczione na podstawie nowych wzorów, są przedstawione. Indexed and abstracted (from vol. 32(1) 2007) in Science...
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The Effect of CO2 Gas Emissions on the Market Value, Price and Shares Returns
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Non-Wave Variations in Temperature Caused by Sound in a Chemically Reacting Gas
PublikacjaA weakly nonlinear generation of non-acoustic modes in the field of sound in a gas is considered. An exotericchemical reaction of A->B type, which takes place in a gas, may be reversible or not. Two types of sound areconsidered, low-frequency and high-frequency as compared with the characteristic time of a chemical reaction.For both these cases, the governing equations of non-acoustic modes are derived and conclusions of the efficiencyof...
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Standard gas mixtures – indispensable reference materials in the analysis of gaseous media
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Procedure of determination of volatile trihalomethanes in human urine with pervaporation and gas chromatography
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Enantioselective comprehensive two-dimensional gas chromatography of lavender essential oil
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Effects of a rotating magnetic field on gas-liquid mass transfer coefficient
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Some remarks on gas chromatographic challenges in the context of green analytical chemistry
PublikacjaOmówiono możliwości wprowadzenia zasad zielonej chemii analitycznej w odniesieniu do technik chromatograficznych.
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Preparation of environmental samples for gas chromatographic determination of selected organic pollutants
PublikacjaOpisano różne metody izolacji i wzbogacania zanieczyszczeń organicznych z ciekłych, gazowych i stałych próbek środowiskowych. Opisano konstrukcję i testowanie nowych systemów do przygotowania próbek oraz ich zastosowanie w połączeniu z chromatografią gazową do oznaczania zanieczyszczeń organicznych w póbkach rzeczywistych.
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Problems of Measuring Gas Content in Oil in a Two-Phase Flow: A Review
PublikacjaIn view of the necessity of measuring the air content in oil in two-phase flows in the context of general industry, a review of the most popular methods of measuring the air content in oil was carried out. This review includes an assessment of their advantages and disadvantages and of whether they meet criteria such as the degree of filling, the size and number of bubbles, verification, the absence of additional pressure drops,...
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Special Issue on “Advanced Liquid Waste and Gas Waste Treatment Processes”
PublikacjaThe editorial contains a short review of the content of the Special Issue on waste gas and liquid streams treatment strategies.
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From flow to jamming: Lattice Gas Automaton simulations in granular materials
PublikacjaWe introduce the first extension of a Lattice Gas Automaton (LGA) model to accurately replicate observed emergent phenomena in granular materials with a special focus on previously unexplored jamming transitions by incorporating gravitational effects, energy dissipation in particle collisions, and wall friction. We successfully reproduce flow rate evolution, density wave formation, and jamming transition observed in experiments....
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Investigation of solid polymer electrolyte gas sensor with different electrochemical techniques
PublikacjaIn this work solid polymer electrolyte (SPE) amperometric sulphur dioxide sensor is investigated. Nafion was used as a membrane electrode and 1M sulphuric acid as an internal electrolyte. Sensor response to sulphur dioxide was measured. Besides traditional constant voltage amperometry also different electrochemical techniques were used. Results obtained by these methods are compared.
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A commercial gas boiler fitted with the ORC module as perspective solution for households
PublikacjaIn this paper the applicability of the commercial gas boiler (De Dietrich DTG X23N) coupled with the laboratory prototype micro ORC setup was experimentally studied. The main objective was to determine the working fluid capability to obtain required temperatures of vapour prior to the turbine, attainable heat rates and efficiencies of the whole system. The boiler thermal power was 25 kW. Tests were carried out with a single stage...
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CLAY MINERALS – MINERALOGY AND PHENOMENON OF CLAY SWELLING IN OIL & GAS INDUSTRY
PublikacjaAmong the minerals found in the earth's crust, clay minerals are of the widest interest. Due to the specific properties such as plasticity, absorbing and catalytic properties clay minerals are used in many industries (oil & gas, chemistry, pharmacy, refractory technology, ceramics etc.). In drilling, a phenomenon of swelling clays is frequently observed. It has an important impact on the cementing quality. During the last few decades...
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Thermal self-action effects of acoustic beam in a vibrationally relaxing gas
PublikacjaThermal self-action of acoustic beam in a molecular gas with excited internal degrees of molecules’ freedom, is studied. This kind of thermal self-action differs from that in a Newtonian fluid. Heating or cooling of a medium takes place due to transfer of internal vibrational energy. Equilibrium and non-equilibrium gases, which may be acoustically active, are considered. A beam in an acoustically active gas is self-focusing unlike...
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Low and high energy explosive materials used in shale gas recovery
PublikacjaNowadays the explosives are widely used in many areas of life, including industry and mining. A wide range of explosive materials is used in the petroleum industry - from low to high explosives. Recently, as the unconventional oil and gas production became possible, explosives are also found to be used in perforators during the pre-completion stage of the fracturing process. This paper presents literature on theoretical and practical...
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Control of mass concentration of reagents by sound in a gas with nonequilibrium chemical reactions
PublikacjaThe weakly nonlinear dynamics of a chemically reacting gas is studied. Nonlinear interaction of acoustic and nonacoustic types of motion are considered. We decompose the base equations using the relationships of the gas-dynamic perturbations specific for every type of motion. The governing equation for the mass fraction of a reagent influenced by dominating sound is derived and discussed. The conclusions concern the equilibrium...
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Operational causes of fatigue failures within the passages of gas turbine engines
PublikacjaThe short profile of a fatigue wear process of gas turbine engine's constructional elements has been introduced in the article. The primary causes of a fatigue cracks formation within the mechanical system as well as within the passages of the engine have been showed. Especial attention was devoted to the low-cycle fatigue, what is associated with unsteady thermal-flow processes being worked out in the passages.The selected damages...
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Dissociative electron attachment to gas phase thiothymine: experimental and theoretical approaches
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Standard gas mixtures- indispensable reference materials in the analysis of gaseous media
PublikacjaIn recent years the need for the quality control and assurance of analytical measurement results has been particularly strongly emphasised. Certified reference materials play an invaluable role in this process. The article characterises the basic types of reference materials, focusing in particular on those in the gaseous state. It also reviews the literature on the techniques of preparing standard gas mixtures over the last ten...
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Degradation of protective coatings in steel chimneys of flue gas desulfurisation system
PublikacjaThis paper presents problems associated with corrosion of steel stacks and changes in philosophy of corrosion protection when implemented into flue gas desulphurization systems. In-situ tests were taken by means of electrochemical impedance spectroscopy at the stack which discharges flue gas before wet lime/limestone desulphurization. A very quick electrolyte absorption by the spherical infill vinylester coating was found using...