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Search results for: GAS-PHASE
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On design and analysis of flow characteristics of the last stage of gas-steam turbine
PublicationResearch regarding blade design and analysis of flow have been conducted for over a century. Meanwhile new concepts and design approaches were created and improved. Advancements in information technologies allowed to introduce computational fluid dynamics (CFD) and computational flow mechanics (CFM). Currently a combination of mentioned methods is used for design of turbine blades. These methods enabled us to improve flow efficiency...
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Design and computational fluid dynamics analysis of the last stage of innovative gas-steam turbine
PublicationResearch regarding blade design and analysis of flow has been attracting interest for over a century. Meanwhile new concepts and design approaches were created and improved. Advancements in information technologies allowed to introduce computational fluid dynamics and computational flow mechanics. Currently a combination of mentioned methods is used for the design of turbine blades. These methods enabled us to improve flow efficiency...
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Flow Maps and Flow Patterns of R1233zd(E) in a Circular Minichannel at Low, Medium and High Values of Saturation Pressure
PublicationThere is a gap in knowledge regarding the flow pattern of low-boiling working fluids in the range of high saturation temperatures (above 120°C) and medium and high reduced pressures (0.5-0.9). Data are present in the literature for similar values of reduced pressures, but for lower values of saturation temperature. This is due to the existing refrigeration applications of these working fluids. At high values of reduced pressure,...
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EVALUATION OF LIQUID-GAS FLOW IN PIPELINE USING GAMMA-RAY ABSORPTION TECHNIQUE AND ADVANCED SIGNAL PROCESSING
PublicationLiquid-gas flows in pipelines appear in many industrial processes, e.g. in the nuclear, mining, and oil industry. The gamma-absorption technique is one of the methods that can be successfully applied to study such flows. This paper presents the use of thegamma-absorption method to determine the water-air flow parameters in a horizontal pipeline. Three flow types were studied in this work: plug, transitional plug-bubble,...
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Investigations of the Working Process in a Dual-Fuel Low-Emission Combustion Chamber for an FPSO Gas Turbine Engine
PublicationThis investigation is devoted to an analysis of the working process in a dual-fuel low-emission combustion chamber for a floating vessel’s gas turbine. The low-emission gas turbine combustion chamber with partial pre-mixing of fuel and air inside the outer and inner radial-axial swirlers was chosen as the object of research. When modelling processes in a dual-flow low-emission gas turbine combustion chamber, a generalized method...
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Solid phase microextraction: state of the art, opportunities and applications
PublicationSolid phase microextraction is one of the most popular green techniques used for sample preparations in analytical chemistry. It is a simple, rapid, sensitive, and solvent-free technique. Since SPME was first introduced in the early 1990s, there has been an intensification of research in order to elaborate new methodical solutions in many research facilities around the world, which could increase the use of this technique. More...
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Electron attachment and electron iozization of acetic acid clusters embedded in helium nanodroplets
PublicationThe effect of incident electrons on acetic acid clusters is explored for the first time. The acetic acid clusters are formed inside liquid helium nanodroplets and both cationic and anionic productsejected in to the gas phase aredetected by mass spectrometry.
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Time Delay Estimation in Two-Phase Flow Investigation Using the γ-Ray Attenuation Technique.
PublicationTime delay estimation is an important research question having many applications in a range of technologies. Measurement of a two-phase flow in a pipeline or an open channel using radioisotopes is an example of such application. For instance, the determination of velocity of dispersed phase in that case is based on estimation of the time delay between two stochastic signals provided by scintillation probes. The proper analysis...
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The Influence of Gas Mixture in the Glow-Discharge Nitriding Process of Austenitic Stainless Steel on Characteristic of Nitrided Cases
PublicationAustenitic stainless steels characterize with excellent corrosion resistance, although low mechanical properties. In many cases that limits their exploitation in industrial applications. Moreover, austenitic stainless steel is susceptible to local corrosion in the presence of halide ions. In present works, it was emphasized that the nitriding of austenitic stainless steels gives some potential abilities to obtain beneficial effect...
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Polymeric metal‐containing ionic liquid sorbent coating for the determination of amines using headspace solid‐phase microextraction
PublicationThis study describes the design, synthesis, and application of polymeric ionic liquid sorbent coatings featuring nickel metal centers for the determination of volatile and semivolatile amines from water samples using headspace solidphase microextraction. The examined polymeric ionic liquid sorbent coatings were composed of two ionic liquid monomers (tetra(3-vinylimidazolium)nickel bis[(trifluoromethyl)sulfonyl]imide [Ni2+(VIM)4]...
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Preparation and Characterization of Au/Pd Modified-TiO2 Photocatalysts for Phenol and Toluene Degradation under Visible Light—The Effect of Calcination Temperature
PublicationRutile loaded with Au/Pd nanoparticles was prepared using a water-in-oil microemulsion system of water/AOT/cyclohexane followed by calcination.Theeffect of calcination temperature (from350 to 700∘C) on the structure ofAu/Pd nanoparticles deposited at rutile matrix and the photocatalytic properties of Au/Pd-TiO2 was investigated in two model reactions (toluene degradation in gas phase and phenol degradation in aqueous phase). The...
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Comprehensive two-dimensional gas chromatography for determination of the terpenes profile of blue honeysuckle berries
PublicationTerpenes are the main group of secondary metabolites, which play essential role in human. The establishment of the terpenes profile of berries of different blue honeysuckle cultivars was achieved by headspace solid-phase microextraction coupled with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (HS-SPME/GCGC-TOFMS). The berries were found to contain 44 terpenes identified by GCGC-TOFMS....
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Recent advances on SOA formation in indoor air, fate and strategies for SOA characterization in indoor air - A review
PublicationRecent studies proves that indoor air chemistry differs in many aspects from atmospheric one. People send up to 90 % of their life indoors being exposed to pollutants present in gas, particle and solid phase. Particle phase indoor is composed of particles emitted from various sources, among which there is an indoor source – secondary chemical reactions leading to formation of secondary organic aerosol (SOA). Lately, researchers'...
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Determination of volatile organic compounds in water samples using membrane-solid phase microextraction (M-SPME) (headspace version)
PublicationThe results of a study on the use of membrane-solid phase microextraction (M-SPME) for sampling volatile organic compounds (VOCs) from the headspace above the liquid medium are presented. The sampled VOCs were subsequently quantified by gas chromatography (GC). Two systems were compared in this study, i.e. a novel two-phase sorption system (M-SPME), and a commercial fibre. Headspace sampling using SPME was optimized with respect...
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Removal of VOCs from air and assessment of dominant species in a peat-perlite biotrickling filter
PublicationAir pollution has become a major concern because it is inevitably connected with the rapid development of both industrial and residential areas. Volatile organic compounds (VOCs) are emitted from various anthropogenic sources e.g. transportation, factories or landfills as well as recycling factories. It is problematic not only because of the direct impact on humans and environment but also from economy viewpoint as it increases...
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Charge dependence of fragmentation process induced by ion collisions with furan molecule
PublicationThe goal of this work is to describe the system evolution after ion-molecule interaction. We combine different quantum chemistry and statistical mechanics approaches in order to give extended description of the process. Herein we report on a recent study of the fragmentation mechanism of neutral, singly- and doubly-ionized furan molecule in the gas phase.
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Positron Scattering and Annihilation in Organic Molecules
PublicationIn this paper, we address the problem of connecting positron lifetimes in liquids with collision cross sections in gases. We present the analyses of annihilation lifetime spectra of positrons in the liquid benzene, c-hexane, n-hexane, methanol and ethanol and calculations of scattering cross sections of positrons with benzene and c-hexane in the gas phase.
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Research on the separation properties of empty-column gas chromatography (EC-GC) and conditions for simulated distillation (SIMDIS)
PublicationThe paper presents the results of investigations on new procedures of determination of selected cleaning additives in diesel fuel. Two procedures: one-step analysis using gas chromatography with flame ionization detection (GC-FID) or mass spectrometry (GC-MS) and a two-step procedure in which normal-phase high-performance liquid chromatography (NP-HPLC) was used for preliminary separation of the additives, were compared. The additive...
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Analytical method for calculation of heat source temperature drop for the Organic Rankine Cycle application
PublicationIn the paper presented are considerations on the cooperation of the limited capacity heat source with the Organic Rankine Cycle unit. Usually the heat source providing thermal energy to the Organic Rankine Cycle (ORC) may have twofold characteristics. It can be in the form of a single phase fluid, i.e. as hot exhaust gas or hot liquid, or in some cases it may be available as a phase changing fluid, as for example, technological...
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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
PublicationVolatile 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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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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Determination of Terpene Profile in Cape gooseberry (Physalis peruviana L.) with Use of HS-SPME/GCxGC-TOFMS Method
PublicationFresh fruits and products made of them, especially fruit juice, provide the basic energetic substances (simple and complex sugars) and are a source of health beneficial vitamins, macro and microelements, antioxidants and compounds which are classified together with essential oils (for example terpenes), which positively affect human s health. The terpenes profile of cape gooseberry was determined by headspace solid--phase microextraction...
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“Shadow” vs. “Phase 3D” method within endoscopic examinations of marine engines
PublicationA visual investigation of surfaces creating internal, working spaces of marine combustion engines by means of specialized view-finders so called endoscopes is at present almost a basic method of technical diag-nostics. The surface structure of constructional material is visible during investigations like through the magnifying glass (usually with a precisely determined magnification), which makes possible a detection, recognition...
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Removal of cyclohexane vapors from air in biotrickling filters: Effects of gas mixture composition and circular economy approach
PublicationThis work presents results of investigations on biotrickling filtration of air polluted with cyclohexane co-treated in binary, ternary and quaternary volatile organic compounds (VOCs) mixtures, including vapors of hexane, toluene and ethanol. The removal of cyclohexane from a gas mixture depends on the physicochemical properties of the co-treated VOCs and the lower the hydrophobicity of the VOC, the higher the removal efficiency...
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Usuwanie lotnych związków organicznych z fazy gazowej z zastosowaniem cieczy jonowych
PublicationUżycie cieczy jonowej do usuwania LZO jest limitowane przez rozpuszczalność usuwanych związków. Dane literaturowe sugerują, że ciecze jonowe jako faza membranowa mogą być z powodzeniem stosowane do selektywnej separacji węglowodorów aromatycznych z mieszanin węglowodorów aromatycznych i alifatycznych. Przedmiotem pracy było kompleksowe opisanie procesu separacji LZO z fazy gazowej z uwzględnieniem czynników wpływających na efektywność...
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Determination of dryout localization using a five-equation model of annular flow for boiling in minichannels
PublicationDetailed studies have suggested that the critical heat flux in the form of dryout in minichannels occurs when the combined effects of entrainment, deposition, and evaporation of the film make the film flow rate go gradually and smoothly to zero. Most approaches so far used the mass balance equation for the liquid film with appropriate formulations for the rate of deposition and entrainment respectively. It must be acknowledged...
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Application of response surface methodology to optimize solid-phase microextraction procedure for chromatographic determination of aroma-active monoterpenes in berries
PublicationMost of scientific papers concern the qualitative or semi-quantitative analysis of aroma-active terpenes in liquid food matrices. Therefore, the procedure based on solid-phase microextraction and comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry for determination of monoterpenes in fresh berries was developed. The optimal extraction conditions using divinylbenzene-carboxen-polydimethylsiloxane fiber...
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Low-energy positron scattering from DNA nucleobases: the effects from permanent dipoles
PublicationAb initio quantum calculations for low-energy positron scattering from gas-phase isolated molecular nucleobases which are part of the DNA structure are presented and discussed over the range of 1 eV to 25 eV. The calculations report the integral cross sections (ICSs) and the momentum-transfer cross sections (MTCSs) for Adenine, Guanine, Thymine and Cytosine. The calculations show very clearly the important role of the dominant...
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Au-RE-TiO2 nanocomposites: Surface characteristics and photoactivity
PublicationThe photocatalysts based on TiO2 co-doped with rare earth metal (RE) and gold nanoparticles have been prepared using a sol-gel method and followed by gold reduction. Specific surface areas of the modified photocatalysts were calculated by the Brunauer-Emmett-Teller method (BET). Diffuse reflectance spectra of the obtained photocatalysts were recorded in a UV-Vis spectrophotometer (DRS UV-Vis). The influence of the type of rare...
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Analysis of cyclone separator solutions depending on SEC outlet conditions in nCO2PP
PublicationUtilization of spray ejector condenser in order to carry out direct-contact condensation of vapour with inert gas (CO2) on a spray of subcooled liquid integrated with separator (to make pure CO2) has been proposed for the task of condensation and CO2 separation in the negative CO2 emission gas power plant. Condensation and separation has a significant impact on the thermodynamic efficiency of the entire negative CO2 emission gas...
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A study of the photoelectron spectra of α-tetrahydrofurfuryl alcohol over the outer valence energy region (9–25 eV)
PublicationPhotoelectron spectra of α-tetrahydrofurfuryl alcohol (THFA) molecules, the threshold spectrum and spectra for constant photoelectron energies, have been measured over the photon energy range 9–25 eV. Analysis of the photoelectron spectra has allowed overlapping photoionization bands to be separated, tentatively assigned and their vertical photoionization energies to be determined. These energies are compared with existing theoretical...
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Matrix solid-phase dispersion (MSPD) as simple and useful sample preparation technique for determination of polybrominated diphenyl ethers (PBDEs) in dust
PublicationIn the present study a novel analytical procedure for the determination of polybrominated diphenylethers in dust samples was developed.The main aim of the research was the selection of the optimum conditions of the matrix solid-phasedispersion before thefinal determination of polybrominated diphenyl ethers in dust samples. In order toassess the best usefulness of this technique, a favourable ratio of sample amount to the mass ofdispersing...
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Direct-contact condensation from vapour- gas mixture in a spray ejector condenser for negative CO2 power plant
PublicationDirect-contact condensation of vapour containing the inert gas on a spray of subcooled liquid exists in a number of technical applications. For example, it may be found in the nuclear industry (e.g. pressurized jet under normal operating conditions, in safety analyses) or in the chemical industry (e.g. mixing-type heat exchanger, degasser, sea water desalting). The problem is also essential to modelling and analysis of some...
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CO2 capture through direct-contact condensation in a spray ejector condenser and T- junction separator
PublicationThe design principle underlying the steam condensation and CO2 purification in a gas power plant with a focus on reducing CO2 emissions encompasses the deployment of a spray ejector condenser (SEC) and separator. This innovative system facilitates direct-contact condensation of steam with non-condensable gas (CO2) by inter acting with a spray of subcooled water, seamlessly integrated with a T-junction separator mechanism aimed...
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Zr‐Based Metal‐Organic Framework UiO‐66/Ultem® 1000 Membranes for Effective CO2/H2 Separation
PublicationMixed-matrix membranes (MMMs) using UiO-66 nanofillers as dispersing inorganic phase and polyetherimide (PEI) as continuous polymeric matrix were synthesized. Different UiO-66 loadings of 10, 20, and 30 wt % were applied. The morphology and UiO-66 dispersion over the prepared MMMs were examined. Gas separation measurements were performed for H2/CO2 gas mixture to evaluate the influence of UiO-66 on the separation yield of resulting...
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Studies of the separation performance of silanized silica gel for simulated distillation
PublicationWe present the results of investigations of the chromatographic (sorptive) properties of silanized silica gel as a stationary phase for gas chromatography used for simulated distillation. Commercially available silanized sorbent (particle diameter range 63–200 m, average pore size 60 Å) was sieved to obtain the 80–100 mesh fraction (180–150 m). The obtained results revealed that silanized silica gel allows the complete separation...
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Air trapping problem during infiltration on the large areas
PublicationThe process of flow modeling in unsaturated porous medium is often found in many fields of sciences: geology, fluid mechanics, thermodynamics, microbiology or chemistry. Problem is relatively complicated due to complexity of the system which contains three phases: water, air and soil skeleton. The flow of water in such a medium can be described using two-phase (2PH) flow formulation, which accounts the inflow of air and water phases,...
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Understanding the early-stage release of volatile organic compounds from rapeseed oil during deep-frying of tubers by targeted and omics-inspired approaches using PTR-MS and gas chromatography
PublicationDuring deep-frying, a plethora of volatile products is emitted with the fumes. These compounds could act as oil quality indicators and change the indoor air composition leading to health risks for occupants. The presented experiments focus on deep-frying of different tubers in rapeseed oil at different frying temperatures. Here, two scenarios for real-time monitoring of volatile organic compounds (VOCs) using proton transfer reaction...
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Ionogel sorbent coatings for determining organophosphorus and pyrethroid insecticides in water and fresh juice samples by headspace-solid phase microextraction
PublicationThe sol–gel method yielded three different ionogel sorbent coatings that were obtained based on a silica material containing ionic liquids (ILs) immobilized in its pores. Two ILs, triethylsulfonium bis(trifluoromethylsulfonyl) imide [Set3][TFSI] and 1-butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide [C4C1Pip][TFSI], as well as their equimolar mixture [Set3/C4C1Pip], were used to obtain ionogel fibers. The developed...
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A rapid dispersive liquid–liquid microextraction of antimicrobial onion organosulfur compounds in animal feed coupled to gas chromatography-mass spectrometry
PublicationA rapid analytical procedure is proposed for determining two antimicrobial onion organosulfur compounds, propyl disulfide (PDS) and propyl propane thiosulfonate (PTSO), in animal feed. The use of PTSO as a natural ingredient in animal feed is allowed due to its antimicrobial activity against pathogenic organisms. Two analytical methodologies using gas chromatography coupled to mass spectrometry (GC-MS) are compared. After the extraction...
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Noble metal modified TiO2 microspheres: Surface properties and photocatalytic activity under UV-vis and visible light
PublicationComposite photocatalysts that consist of TiO2and noble metal nanostructures have been considered tobe the promising and pivotal material for accessible enhancement of the efficiency in the photocatalyticprocess carried out in the aqueous and gas phases. In this work we fabricated porous TiO2microspheresthrough a hydrothermal process followed by photochemical reduction of noble metal nanoparticles atthe TiO2surface. The morphology...
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Preparation, characterization and photocatalytic activity of TiO2 microspheres decorated by bimetallic nanoparticles
PublicationComposite photocatalysts that consist of TiO2and noble metal nanostructures have been considered tobe the promising and pivotal material for accessible enhancement of the efficiency in the photocatalyticprocess carried out in the aqueous and gas phases. In this work we fabricated porous TiO2microspheresthrough a hydrothermal process followed by photochemical reduction of noble metal nanoparticles atthe TiO2surface. The morphology...
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Highly Visible-Light-Photoactive Heterojunction Based on TiO2 Nanotubes Decorated by Pt Nanoparticles and Bi2S3 Quantum Dots
PublicationA heterojunction with excellent visible light response and stability based on titanium dioxide nanotubes (TiO2 NTs), bismuth sulfide quantum dots (Bi2S3 QDs), and platinum nanoparticles (Pt NPs) is proposed. Both Pt NPs (3.0 ± 0.2 nm) and Bi2S3 QDs (3.50 ± 0.20 nm) are well distributed on the (i) top parts, (ii) inner walls, and (iii) outer walls of the TiO2 NTs. Visible-light-induced photoreaction was initialized by excitation...
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Electron impact fragmentation of pyrrole molecules studied by fluorescence emission spectroscopy
PublicationThe fluorescence emission spectroscopy using electron impact excitation technique was employed to study fragmentation processes of the gas phase pyrrole molecules. The following excited fragmentation species were observed by detection of their fluorescence decay: the atomic hydrogen H(n), n = 4-7 and the diatomic CH(A2Δ), CN(B2Σ+), NH(A3Π) and C2(d3Πg) fragments. These atomic and molecular products differ from those previously...
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Electron energy-loss spectroscopy of excited states of the pyridine molecules
PublicationElectron energy-loss spectra of the pyridine, C5H5N, molecules in the gas phase have been measured to investigate electronic excitation in the energy range 3.5–10 eV. The applied wide range of residual electron energy and the scattering angle range from 10 ◦ to 180 ◦ enabled to differentiate between optically-allowed and -forbidden transitions. These measurements have allowed vertical excitation energies of the triplet excited...
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Capillary gas chromatography using a -cyclodextrin forenantiomeric separation of methylamphetamine, its precursors andchloro intermediates after optimization of the derivatization reaction
PublicationtThe enantiomeric ratio of methylamphetamine (MAMP) is closely related to the optical activity of precur-sors and reagents used for the synthesis and this knowledge can provide useful information concerningthe origins and synthetic methods used for illicit manufacture. The information can be utilized for reg-ulation of the precursors and investigation of the manufacturing sources but this requires analyticalprocedures to determine...
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Solubility of Methane in Water: Some Useful Results for Hydrate Nucleation
PublicationIn this paper, the solubility of methane in water along the 400 bar isobar is determined by computer simulations using the TIP4P/Ice force field for water and a simple LJ model for methane. In particular, the solubility of methane in water when in contact with the gas phase and the solubility of methane in water when in contact with the hydrate has been determined. The solubility of methane in a gas–liquid system decreases as temperature...
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KTaO3-based nanocomposites for air treatment
PublicationThe advantage is that photocatalytic methods allow removing VOCs, NOx, SO2, deodorants, and microorganisms at the same system. The new third generation of photoactive materials activated by low powered and low cost irradiation sources (such as LEDs or black fluorescent UV lamps) can be used as photocatalysts in air purification systems. A series of single semiconductors and their nanocomposites combination were prepared using hydrothermal...
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Electron energy-loss spectroscopy of excited states of the diazine molecules: Pyridazine
PublicationExcitation of the valence electronic states of the pyridazine molecules in the gas phase have been studied using the technique of electron energy-loss spectroscopy. Varying the electron scattering conditions, the residual electron energy and scattering angle, enabled the optically-allowed and -forbidden excitations to be differentiated. The measured energy-loss spectra enabled the vertical excitation energies of the observed states...
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Spatial characterization of H 2: CH 4 dissociation level in microwave ECR plasma source by fibre-optic OES
PublicationSpatially resolved optical emission spectroscopy (SR-OES) was used to investigate microwave activated H2/Ar/CH4 plasma under conditions of the electron cyclotron resonance (ECR). The chemistry and composition of the gas phase were studied using self-designed fibre-optic system with echelle type spectrometer during CVD deposition of polycrystalline diamond. One-dimensional intensity profiles of the main species were collected along...