Showing papers on "Vapours published in 2004"
TL;DR: In this paper, the sensitivity of several conductive polymer composites (CPC) to solvent vapours has been studied, and the diffusion curve shape analysis together with the use of CPC of different chemical nature and structure (comonomer content and crystallinity) is expected to decrease the number of CPC necessary for vapour detection.
Abstract: The sensitivity of several conductive polymer composites (CPC) to solvent vapours has been studied. Electrical properties of three CPC poly(amide12-b-tetramethylene oxide)-carbon black (PEBAX-CB), poly(propylene)-carbon black (PP-CB) and poly(ethylene-co-ethyl acrylate)-carbon black (EEA-CB) were investigated in the presence of four organic solvent vapours, chloroform, toluene, methanol and ethanol. The experiments show that it is possible to use extruded CPC textiles to combine acceptable conductivity for heating and satisfying response for vapour detection. Moreover, the investigation of the mechanisms involved during the solvent vapours diffusion into the CPC, shows that not only the response of the systems Δ R / R 0 can be used for vapour detection but also the shape of the curves, i.e., the diffusion mode characterised by Δ R / R max versus t curves slope and onset. The diffusion curve shape analysis together with the use of CPC of different chemical nature and structure (comonomer content and crystallinity) is expected to decrease the number of CPC necessary for vapour detection.
85 citations
TL;DR: In this article, the impedance analysis of thickness shear mode (TSM) resonators coated with calixarene films was successfully exploited for the registration of organic solvent vapours of relatively high (pre-explosive) concentrations.
Abstract: The impedance analysis of thickness shear mode (TSM) resonator coated with calixarene films was successfully exploited for the registration of organic solvent vapours of relatively high (pre-explosive) concentrations. The impedance analysis consisted of fitting the experimental admittance spectra of TSM resonators to the equivalent circuit model using a highly accurate and reliable least squares algorithm. This approach allowed simultaneous monitoring of the changes in mass and viscoelastic properties of the sensitive membrane caused by adsorption of organic vapours and therefore enables both quantification and discrimination between the vapours of different types of organic solvents, such as hexane and toluene.
53 citations
TL;DR: In this article, the electrical properties of two conductive polymer composites (CPC) not yet studied in the literature, poly(amide12-b-tetramethylene oxide)-carbon black (PEBAX-CB) and poly(ethylene-co-ethyl acrylate)-carbon Black (EEA-CB), were studied as a function of processing conditions (in the melt by extrusion and from solution by casting).
44 citations
01 Jan 2004
TL;DR: In this article, the response of screen-printed thick-films of NiO/TiO/sub 2/ to organic solvent vapours was studied and it was found that these films displayed a significant resistance change in response to the vapours even at room temperature.
Abstract: The response of screen-printed thick-films of NiO/TiO/sub 2/ to organic solvent vapours was studied. It was found that these films displayed a significant resistance change in response to the vapours even at room temperature. The sensors displayed an inherent selectivity, proving most sensitive to toluene and propanol vapour; with comparatively low responses exhibited towards ethanol and methanol vapours. Very fast response and recovery times of 9 s and 16 s respectively were recorded for the devices upon exposure to 4000 ppm step changes in propanol concentration.
10 citations
TL;DR: In this paper, the synthesis of a poly(p-phenylene-vinylene) derivative bearing dodecanoylsulfanyl side-groups (12COS-PPV) was reported.
Abstract: We report the synthesis of a novel poly(p-phenylene-vinylene) derivative bearing dodecanoylsulfanyl side-groups (12COS-PPV). Good solubility in organic solvents was achieved. The average molecular weight was around 30 000, the energy gap 2.8 eV and the thermal stability up to 130°C. Doping with iodine vapours rose conductivity to 2·10 -6 S/cm. Gas sensors made from FeCl3-doped 12COS-PPV showed an unusual behaviour responding to only four of the eight different organic solvent vapours tested. Recoveries from the responses are not complete, but are reproducible and can be used to discriminate between the four solvents. Quantitative analyses are also possible since there is a good linear correlation between relative response and concentration.
8 citations
7 citations
TL;DR: Antifungal activities of volatile vapours of essential oils were investigated, finding spores of dermatophytic filamentous fungi are more susceptible to volatile vapour strength than mycelia.
Abstract: Antifungal activities of volatile vapours of essential oils were investigated. Volatile vapours of test essential oils except Cedar-wood and Pachouri showed inhibitory activity against test fungi. Volatile vapours of Birch essential oils exhibited fungistatic activity against dermatophytic filamentous fungi while others did fungicidal activity. Spores of dermatophytic filamentous fungi are more susceptible to volatile vapours of essential oils than mycelia.
6 citations
Patent•
07 Jan 2004
TL;DR: In this article, water and low molecular weight reactive chemicals compounds are removed from pyrolysis vapours and liquid by evaporation and/or liquid by preventing complete vapour condensation.
Abstract: Water and low molecular weight reactive chemicals compounds are removed from the pyrolysis vapours and/or liquid by evaporation and/or preventing complete vapour condensation. A process for the preparation of liquids by pyrolysis, comprises the rapid pyrolysis of biomass and/or similar organic material in order to vaporise volatile compounds, and the condensing of these vapours to form a liquid. Water and low molecular weight reactive chemical compounds are removed from the pyrolysis vapours and/or liquid by evaporation and/or preventing complete vapour condensation, in order to improve pyrolysis liquid quality. An Independent claim is also included for the process apparatus, comprising a pyrolyser (1), condenser (2) and at least one device (10, 11) for removing water and low molecular weight reactive chemical compounds.
2 citations
01 Jan 2004
2 citations
01 Jan 2004
TL;DR: In this paper, the critical energy E* of direct initiation of a detonation wave (DW) is accepted as the main criterion parameter of detonation hazards of gaseous mixtures.
Abstract: The critical energy E* of direct initiation of detonation wave (DW) is accepted as the main criterion parameter of detonation hazards of gaseous mixtures. The blast explosion approximation is proposed to use at experimental definition of E*. This technique is identically suitable both to various mixtures and various initiators with of large distinctions in the spatial-temporary energy-release characteristics (flame igniters, electrical or laser spark, exploding wire, explosive, high-speed bullet...). The priority at theoretical definition of critical detonation energy is given up to «multi-points» initiation model (MPI) based on DW transverse waves collisions as the microinitiators of a detonation («hot» points). The hazard parameters were calculated with the help of Computer Code «SAFETY». The basic parameters of detonation and explosive hazards of some typical fuels (interesting from scientific and practical points of view) are presented in a wide range of its concentration in mixtures with oxygen and air, and at dilution of inert gases. The dependence of critical initiation energy E* on percentage of fuel in a mixture allows to find out comparative detonation hazards of various combustible systems at plane, cylindrical and spherical initiation. Calculated results are in a good agreement with experimental data.
01 Jan 2004
01 Jan 2004
TL;DR: In this article, the model of adsorbate pore filling correction was applied to describe ethanol vapour diffusion from a stream of air in particles of activated carbon, and the calculated values of pore diffusivity'AB D were ranging from 1.06×10 -6 to 2.60×10 −6 m 2 s -1.
Abstract: The model of adsorbate pore filling correction was applied to describe ethanol vapour diffusion from a stream of air in particles of activated carbon. The calculated values of pore diffusivity ' AB D were ranging from 1.06×10 -6 to 2.60×10 -6 m 2 s -1 . Transport of ethanol vapours in pores of activated carbon Supersorbon HS-4 proceeded via combination of Knudsen and surface diffusion. The values of effective diffusivity De calculated from the pore diffusivity ' AB
Patent•
23 Aug 2004
TL;DR: In this article, a highly-ordered silica and an oxidising agent is proposed for the adsorption and decomposition of toxic vapours, which is suitable for use in a filtration device.
Abstract: A material suitable for the adsorption and decomposition of toxic vapours, comprising a highly-ordered silica and an oxidising agent. The material is efficient in adsorbing and oxidising toxic vapours and is suitable for use in a filtration device. Methods of preparing the material and methods of using them are also described and claimed.
Patent•
19 Mar 2004
TL;DR: In this article, a method for improving the efficiency of recovering fuel vapours present in a gas mixture is proposed. But the method is limited to a single step, which involves a step involving the liquefaction of the fuel condensates using a condenser.
Abstract: The invention relates to a method of improving the efficiency of recovering fuel vapours present in a gas mixture (2). The inventive method comprises a step involving the liquefaction of the fuel vapours using a condenser (5), in order to recover the fuel condensates. According to the invention, during the aforementioned liquefaction step, the method also consists in: ensuring that the fuel condensates are separated from the residual vapours at the outlet of the condenser (5), and returning the residual vapours upstream of the condenser (5) for another liquefaction step.