Showing papers on "Vapours published in 2015"

Swelling of PDMS networks in solvent vapours; applications for passive RFID wireless sensors

Abstract: The relative degree of swelling of a poly(dimethylsiloxane) (PDMS) network in organic vapours is demonstrated to be related to the chemical and physical properties of the organic compounds. The swelling ratio, based on volume change, QV, is directly correlated with the Hansen solubility parameters, δd, δp and δh and the vapour pressures of the organic vapours employed. A practical use for such PDMS networks in combination with an understanding of the relationship is demonstrated by the use of PDMS as a mechanical actuator in a prototype wireless RFID passive sensor. The swelling of the PDMS displaces a feed loop resulting in an increase in transmitted power, at a fixed distance.

Operating temperature dependent ethanol and formaldehyde detection of spray deposited mixed CdO and MnO2 thin films

Abstract: CdO–MnO2 mixed oxide films are synthesized using a spray pyrolysis method. The structural study confirms the polycrystalline nature of the film and also confirms that the films are in a mixed oxide state. The morphological study reveals that the crystallite size is around 30 nm to 40 nm in size with spherical morphology. Energy dispersive spectroscopy confirms the presence of cadmium, manganese and oxygen in a mixed oxide state. The prepared CdO–MnO2 film is highly sensitive to ethanol vapours at ambient temperature. The resistance of the film decreases drastically when it is exposed to ethanol and formaldehyde vapours. The prepared CdO–MnO2 is highly sensitive to ethanol at ambient temperature and to formaldehyde vapour at 393 K. The sensitivity, selectivity, response time, recovery time and stability of the CdO–MnO2 film towards ethanol and formaldehyde sensing are reported in the present work.

A numerical model for the fractional condensation of pyrolysis vapours

Abstract: Experimentation on the fast pyrolysis process has been primarily focused on the pyrolysis reactor itself, with less emphasis given to the liquid collection system (LCS). More importantly, the physics behind the vapour condensation process in LCSs has not been thoroughly researched mainly due to the complexity of the phenomena involved. The present work focusses on providing detailed information of the condensation process within the LCS, which consists of a water cooled indirect contact condenser. In an effort to understand the mass transfer phenomena within the LCS, a numerical simulation was performed using the Eulerian approach. A multiphase multi-component model, with the condensable vapours and non-condensable gases as the gaseous phase and the condensed bio-oil as the liquid phase, has been created. Species transport modelling has been used to capture the detailed physical phenomena of 11 major compounds present in the pyrolysis vapours. The development of the condensation model relies on the saturation pressures of the individual compounds based on the corresponding states correlations and assuming that the pyrolysis vapours form an ideal mixture. After the numerical analysis, results showed that different species condense at different times and at different rates. In this simulation, acidic components like acetic acid and formic acids were not condensed as it was also evident in experimental works, were the pH value of the condensed oil is higher than subsequent stages. In the future, the current computational model can provide significant aid in the design and optimization of different types of LCSs.

Co-TPP functionalized carbon nanotube composites for detection of nitrobenzene and chlorobenzene vapours

Abstract: We report preparation of nanocomposites by non-covalent functionalization of carbon nanotubes (CNTs) with metal-tetraphenylporphyrins (M-TPP). Fourier transform infrared (FTIR) spectroscopy and transmission electron microscopy (TEM) results suggest formation of nanosized clusters of Co-TPP around the CNTs surface. X-ray diffraction studies indicate electronic charge re-distribution and strong interactions among CNTs and Co-TPP on functionalization. The films of the hybrid CNT–M-TPP nanocomposite exhibit change in conductivity on exposure to some chemical vapours. In the present work, the films prepared from the cobalt-TPP functionalized CNTs hybrid composites have been investigated for the detection of chlorobenzene (CB) and nitrobenzene (NB) vapours at room temperature. The films show response time of few seconds on exposure to both the NB and CB vapours while the recovery time for NB is significantly different compared to CB. A distinct and highly reproducible response pattern in the relative changes in resistance, recovery and response times on exposure to the vapours of NB, CB and few other chemicals at room temperature has been exploited to differentiate CB and NB vapours from one another.

Rhodium-decorated MWCNTs for detecting organic vapours

Abstract: In this paper, we describe a new approach for the development of a vapour sensor based on carbon nanotubes decorated with rhodium nanoparticles for detecting organic compounds. The morphology of treated multiwall carbon nanotubes was studied by means of high-resolution transmission electron microscopy (TEM) and the composition by X-ray photoelectron spectroscopy (XPS). Various aromatic and non-aromatic vapours were tested. For non-aromatic vapours, the response kinetics shows that these species are chemisorbed at the surface of carbon nanotubes. On the other hand, with aromatic vapours, the kinetics shows a physisorption behaviour. Also, the developed sensor shows lower sensitivity for non-aromatic than for aromatic vapours. The drift in sensor response remained below 10% after two months of sensor operation, which shows the high stability of the rhodium-carbon nanotubes film.

Detection of volatile organic compounds using optical fibre long period grating modified with metal organic framework thin films

Abstract: An optical fibre long period grating (LPG) modified with a thin film of ZIF-8, a zeolitic immidazol framework (ZIF) material, a subgroup of the metal organic framework (MOF) family, was employed for the detection of organic vapours. ZIF-8 film was deposited onto the surface of the LPG using an in-situ crystallization technique. The sensing mechanism is based on the measurement of the refractive index (RI) change induced by the penetration of the chemical molecules into the ZIF-8 pores. An LPG modified with 5 growth cycles of ZIF-8 responded to exposure to methanol and ethanol vapours.

Vapours Adsorption on Non-porous or Porous Solids: Zeta Adsorption Isotherm Approach

Abstract: Vapours adsorption on non-porous and porous solids: Zeta Adsorption Isotherm Approach Seyed Hadi Zandavi Doctor of Philosophy Graduate Department of Mechanical and Industrial Engineering University of Toronto 2015 The Zeta adsorption isotherm, ZAI, has been extended so it may now be applied to describe the adsorption of molecularly adsorbed gases, of dissociatively adsorbed gases, and of vapours. This isotherm assumes, as a hypothesis to be tested, that the adsorbates consist of differently sized clusters. The ZAI theory is used to derive an expression for predicting the cluster distributions in the adsorbed phase. Cluster distribution predictions are a unique feature of ZAI and they are not available from other adsorption isotherms. For vapours, this isotherm supposes that an adsorbate at pressures less than the saturation-vapour pressure, Ps(T ), consists of molecular clusters with 1, 2, 3 · · · up to a limited maximum value of ζm molecules. Since ζm is bounded, we show that ZAI has no singularities for any pressure. This allows the adsorption of vapours at pressures greater than Ps to be investigated. The cluster distribution predicts the formation of an adsorbed film at a vapour phase pressure greater than Ps. Further, the ZAI is combined with Gibbsian thermodynamics to obtain an expression for the surface tension at the solid-vapour interface, and a method has been proposed for determining the conditions at which an adsorbed vapour becomes an adsorbed liquid. For molecularly gas adsorption, the same procedure is applied; it is found that ζm is unity, meaning there is no clustering. When the same procedure is applied for dissociative

Solvent Vapour-Sensitive Activated Carbon Submicrofibres Based on Electrospun Polyacrylonitrile Fibre Mat

Abstract: Lodz University of Technology, Department of Material and Commodity Sciences and Textile Metrology, Center of Advanced Technologies of Human Friendly Textiles PRO HUMANO TEX, ul. Żeromskiego 116, 90-924 Łodź, Poland E-mail: klata@p.lodz.pl Abstract Precursor polyacrylonitrile submicrofibres with a diameter of about 900 nm, electrospun from polyacrylonitrile/dimethyl sulfoxide (PAN/DMSO) solution, were carbonised and chemically activated. These submicrofibres, characterised by a porous structure more developed than in the case of standard fibres, were investigated as solvent vapour sensors. Sensitivity to vapours of four different fluids: methanol, acetone, benzene & toluene at a low concentration of 200 ppm, was studied directly for fibres and for ones in a prototype textile multilayer system. In experiments the electrical conductivity of carbon fibres was utilised. The response time and sensority coefficient, indicating quantitative changes in electric resistance due to contact with the solvent vapours, were estimated. The activated carbon submicrofibres are characterised by sensitivity, a very short response time not longer than 20 s, stability, and selectivity in relation to vapours of polar and non-polar solvents. The sensitivity to vapours of polar solvents is higher than that to those of non-polar solvents.

SWCNT-aminopolymer composites on mesoporous alumina for fast, room-temperature detection of ultra-low concentrations of NO2 by mediation of water vapour

Abstract: Fabrication of devices that operate at room temperature and detect ultra low levels of gases such as ammonia, nitrogen dioxide and organic vapours could greatly benefit environment monitoring, medical diagnosis, security implementation and disease prevention. Although single-walled carbon nanotubes (SWCNT) and graphene are materials with great potential for such measurements, fundamental deficiencies such as low selectivity and long recovery time (up to 12 h) have prevented their use in practical devices. Here we show that the SWCNT-aminopolymer thin films deposited on alumina membranes can be used for fast and highly reproducible detection of ultra-low levels (down to five parts billion) of nitrogen dioxide at room temperature by the mediation of water vapour. The sensitivity, response time and recovery time of NO 2 molecules are found to be sensitive to polar solvent vapours such as water. Using this property, we obtain a reproducible dynamic baseline, different from the traditionally used dry air (or dry nitrogen) baseline, for the detection of NO 2 gas. The chemiresistors of SWCNT composited with amino polymers showed higher sensitivity to NO 2 in comparison to SWCNT-only chemiresistors fabricated similarly. They showed very small responses to 100 ppm NH 3 and 100 ppm CO in air. The present non-conventional measurement method that exploits the interaction of SWCNT-aminopolymer composites with polar solvent vapours to obtain fast recovery and fast response is a significant advancement in gaining insights for the room-temperature gas detection with carbon-based materials.

Method of paraffin oil preparation

Abstract: FIELD: oil and gas industry.SUBSTANCE: method of thermal oil dewaxing is suggested, it includes the paraffin oil heating in waste heat exchanger, fractionation together with thermolysis vapours supplied as vapour reflux, and circulating part of thermolysis residues with creation of fractionation vapours and mixture of heavy gas oil, and residual fraction. The latter is heated in the furnace and is subjected to thermolysis and separation with production of vapours and thermolysis residues, separated to the circulating part and balance part. The fractionation vapours are mixed with stabilisation gas, cooled in the waste hear exchanger, and separated to separation gas used for own needs as fuel, and to wide distilled fraction mixed with the balance part of the thermolysis residues, and are stabilised with separation of the stabilisation gas and prepared oil.EFFECT: simplified method and reduced content by weight of wax in oil, decreasing of its viscosity and pour point.5 cl, 1 dwg

Discharge of fuel vapours from engine adsorber into intake manifold (versions)

Abstract: FIELD: engines and pumps.SUBSTANCE: discharge of fuel vapours from adsorber (150) into intake manifold (46) of engine (10) consists in decrease in the opening of engine throttle (64) and in the increase in forced aspiration developed by compressor (162) connected with the engine (10) when accumulated fuel vapours exceed the threshold magnitude at discharge of said vapours from adsorber (150). Invention discloses the above described method.EFFECT: increased flow of fuel vapours from the adsorber into the engine intake system.10 cl, 5 dwg

Method of fuel oil refining

Abstract: FIELD: oil and gas industry.SUBSTANCE: invention relates to method of fuel oil refining including its heating in the furnace and supply to vacuum column with off-take by side streams of vacuum distillates and tar from bottom of the vacuum column, using circulating reflux and supply to column bottom of the evaporating agent and part of cooled tar, condensation of light hydrocarbon vapours removed from top of the vacuum column, and with separation of uncondensable gases and vapours, and condensate of hydrocarbon vapours. Light hydrocarbon vapours from top of the vacuum column are supplied to the hydraulic ejector, are ejected by the work liquid, and then are supplied to ejecting agent tank, where fresh ejecting agent (make-up) is also supplied, part of liquid from bottom of the ejecting agent tank is cooled and used as work liquid, another part containing condensate of hydrocarbon vapours is mixed with part of light vacuum distillate, and after heating is supplied to bottom of the vacuum column as evaporating agent or to evaporator, from its top the vapours are supplied to bottom of the vacuum column as evaporating agent, and liquid from bottom is supplied to the ejecting agent tank together with make-up, at that above the zone of heated fuel oil supply the heavy vacuum distillate is removed from the column and is mixed with fuel oil before its heating in the furnace.EFFECT: increased removal of vacuum distillates and reduced degree if fuel oil decompounding in the furnace, reduced creating of acid water drains.1 dwg, 2 tbl

Solvent Vapour-Sensitive Activated Carbon Submicrofibres Based on Electrospun Polyacrylonitrile Fibre Mat

Abstract: Precursor polyacrylonitrile submicrofibres with a diameter of about 900 nm, electrospun from polyacrylonitrile/dimethyl sulfoxide (PAN/DMSO) solution, were carbonised and chemically activated. These submicrofibres, characterised by a porous structure more de veloped than in the case of standard fibres, were investigated as solvent vapour sensors. Sensitivity to vapours of four different fluids: methanol, acetone, benzene & toluene at a low concentration of 200 ppm, was studied directly for fibres and for ones in a prototype textile multilayer system. In experiments the electrical conductivity of carbon fibres was utilised. The response time and sensority coefficient, indicating quantitative changes in electric re sistance due to contact with the solvent vapours, were estimated. The activated carbon submicrofibres are characterised by sensitivity, a very short response time not longer than 20 s, stability, and selectivity in relation to vapours of polar and non-polar solvents. The sensitivity to vapours of polar solvents is higher than that to those of non-polar solvents.

Method of manufacturing products from composite materials based on matrix from metal carbides, obtained with application of method of regulated introduction of metal into pores of carbon-containing material of workpiece

Abstract: FIELD: chemistry.SUBSTANCE: method of manufacturing products from composite materials based on a matrix from metal carbides includes the production of a workpiece from a porous carbon-containing material with low density and high open porosity and its metallation by a vapour-liquid phase method. Introduction of metal into pores of the workpiece material is realised by portions in 2 or more doses, alternating it with the portion introduction of carbon by soaking with a coke-forming binding agent with its following solidification and carbonisation. In order to introduce a limited quantity of metal into the pores of the carbon-containing material at intermediate stages of metallation, the workpiece and crucible with metal are placed into a closed retort volume, heated in a vacuum in metal vapours, exposed at the maximal temperature of the metal carbidisation and cooled. The workpiece heating and isothermal exposure at a temperature higher than the evaporation temperature but lower than the maximal temperature of metal carbidisation is carried out at a difference of temperatures between the vapours of metal and the metallated workpiece with the lower temperature on the latter, following heating and isothermal exposure at the maximal temperature of the metal carbidisation - in the absence of the temperature difference, and cooling - with a reverse difference of temperatures or in the absence of the metal vapours The less metal is to be introduced into the pores of the workpiece material, the lower temperature is set on the workpiece and/or the lower difference of temperatures is created between the workpiece and the metal vapours and/or the less time is set on isothermal exposure, and on the contrary.EFFECT: increased strength and oxidation stability of the composite materials.2 cl, 2 tbl

Method of oily wastes processing

Abstract: FIELD: oil and gas industry.SUBSTANCE: oily wastes are heated and subjected to primary separation with the extraction of oil-contaminated water and mechanical impurities. The received partially dewatered oily wastes are mixed up with a diluter and subjected to repeated separation with the production of an oil concentrate and additional quantity of oil-contaminated water and mechanical impurities. The oil concentrate is subjected to fractioning together with vapours of gasoline and diesel fraction stabilisation as well as with vapours of thermal conversion, in result a sulphurous hydrocarbon gas, an unstable gasoline fraction, the diluter, an unstable diesel fraction and bottom fractions are obtained. The sulphurous hydrocarbon gas is treated from hydrogen sulphide with the receipt of a fuel gas and commercial sulphur. The unstable gasoline fraction is stabilised with the receipt of commercial gasoline and stabilisation vapours. The unstable diesel fraction is subjected to catalytic stabilisation by hydrogenation and stabilised with the receipt of commercial marine fuels and stabilisation vapours. The bottom fractions are subjected to thermal conversion with the receipt of vapours and heavy residue used as a power-generating fuel. Oil-contaminated water is treated with the receipt of partially clean water and oily wastes, which are sent for mixing up with a raw material, as well as oil-contaminated mechanical impurities, which are processed in the mixture with the oil-contaminated mechanical impurities received at previous stages into road-building materials.EFFECT: method allows continuous treatment excluding the output of a non-commercial product, improvement of the quality of the commercial product, improvement of industrial and environmental safety, improved labour conditions; the method may be used in the oil refining industry for non-waste processing of emulsion and emulsion suspended oily wastes.5 cl, 1 dwg

Device for steady voltage of preforming machine steam

Abstract: The utility model discloses a device for steady voltage of preforming machine steam, which comprises a tank body, the upper portion both sides of the jar body are equipped with intake pipe and outlet duct respectively, the bottom of the jar body is equipped with the outlet pipe, be equipped with the relief pressure valve in the intake pipe, be equipped with the trap on the outlet pipe. According to the structure, the utility model discloses a device for steady voltage of preforming machine steam, the vapours is after the relief pressure valve of intake pipe, and it is internal to get into the jar, and 1-1.5 standard air pressure within range was dropped to the atmospheric pressure of vapours this moment, through the effect of " L " venturi tube and screen panel, to cool down the vapours, the temperature that makes the vapours is at 110-115 degrees centigrade within range to satisfy the production needs in equipment later stage, water droplet after the vapours liquefaction can splash on dropping on jar ponding of body bottom, and through the effect of baffle, the water droplet after preventing to splash contacts with the vapours once more, through the effect of trap, make jar internal ponding exhaust guarantee simultaneously that the pressure of jar internal vapours can not reduce.

Room Temperature Detection of Benzene Vapours by Tin Oxide Nano Clusters

Abstract: Thin films of tin oxide with nano clusters were deposited using Chemical Vapour Transport technique. The annealed films were used as sensor to detect benzene vapours at room temperature. The response was studied for the concentration range 300-1000 ppm. A comparative study of the response of the nano clustered films to benzene vapours in this range with the response of thin films of Indium tin oxide and tin oxide deposited by the physical vapour deposition method was taken up. Copyright © 2015 IFSA Publishing, S. L.

DC breakdown in vapours of liquids

Abstract: Research of discharges in liquids and their vapours has opened many possibilities for novel applications of non-equilibrium discharges in medicine, fuel and sensor industry, food industry and nanotechnology1,2. As breakdown in liquids is a quite complex phenomenon, research on the breakdown in vapours of relevant liquids can provide initial information necessary to study elementary processes in the gas phase and at surfaces3.

Effect of Metal Vapours on Thermodynamics and Transport Properties of an Arc Plasma

Abstract: Theoretical investigation of nitrogen-iron arc transport phenomena and an arc plasma model in stationary state have studied at low temperature i.e. between 3,500K and 15,000K at atmospheric pressure. Results showed that the presence of small amounts of metal vapours, which have low ionization potential such as iron, modify the plasma parameters. The solution of Elenbaas-Heller gives us some information about the effect of metal vapours emitted from electrode on the characteristics of the arc column. We concluded that a small fraction of metal vapours in the arc column modify the electric field, current and the axial plasma temperature. .

A novel experimental setup to study the nucleation of atmospheric vapours on small nanoparticles

Abstract: We present a novel supersaturation chamber which allows us to expose nanoscale particles to supersaturated vapors in the wide range of temperatures occurring in planetary atmospheres. This chamber, the molecular flow ice cell (MICE), is integrated in the vacuum setup TRAPS and enables us to study adsorption, nucleation and growth processes of condensable vapours as for instance water vapour and carbon dioxide. We will present the experimental setup with focus on MICE. The general function principal of MICE and its limitations will be highlighted and we will elaborate that this new device is able to study adsorption, ice nucleation and growth processes exemplified with CO2 nucleation experiments in the mesosphere of Mars.

Influence of Silver Vapours on the Transport of Nitrogen Plasma Properties

Abstract: Theoretical investigation of nitrogen-silver arc transport properties and an arc plasma model in stationary state have studied at low temperature i.e. between 3500 K and 13,000 K at atmospheric pressure. Results showed that the presence of small amounts of metal vapours, which have low ionization potential such as silver, modify the plasma characteristics. The solution of Elenbaas-Heller gives us some information about the effect of metal vapours emitted from electrode on the characteristics of the arc column. We concluded that a small fraction of metal vapours in the arc column modify the electric field, current and the axial temperature.