Vapours

About: Vapours is a research topic. Over the lifetime, 1153 publications have been published within this topic receiving 15022 citations.

Method and device for pumping out vapours and/or vaporous mixtures and/or gas-vapour mixtures or similar media

Abstract: A method for pumping out vapours and/or vaporous mixtures and/or gas-vapour mixtures and/or similar media in two or more stages from at least one receiver by evacuation is to be developed further so that a final pressure of less than 10 hPa, and preferably in the range 10 hPa to 10 hPa, can easily be achieved, and that it is also ensured that the vapours and/or vaporous mixtures and/or gas-vapour mixtures or similar media can be compressed to atmospheric pressure and pumped, even if partial condensation occurs. This is achieved by having the one or more first, vacuum-producing pumping-out stages (A1) followed by one or more second pumping-out stages (A2) that compress to atmospheric pressure so that the one or more first pumping-out stages or the space surrounding these is pumped out by the one or more second pumping-out stages to below a pressure corresponding to the dew point of the respective medium to be pumped out.

Toxic gas and vapor detection by polyaniline gas sensors

Abstract: investigated by measuring its conductance and mass changes by using a fourprobe method, elemental analysis, and X-Ray fluorescence (XRF) technique. The prepared films were exposed to hydrogen halides, hydrogen cyanide, hydrogen sulphide, halogens, acetic acid, mono-, di-, and trichloroacetic acid, formaldehyde, hexachloroacetone, 1,3,5-trichloromethyl benzene, methylbenzyl bromide, bromoacetone and cyanogen bromide. It is observed that the polyaniline conductance changes are partly due to two-stage sorption perhaps involving the swelling of the polymer and gas diffusion. All the films were exposed to dilute ammonia solution or vapours of organic solvents and swelled before doping, which could modify the mass and electrical measurements. It was demonstrated that slightly additional amounts of HCl gas in tested gases will significantly influence the conductivity. It is concluded that the response mechanism of polyaniline sensing of different gases and vapours is due to a mixed response involving electronic and physical effects. S. Hossein Hosseini1*, S. Hossein Abdi Oskooei2, and Ali Akbar Entezami3

Sensitivity of the electrical admittance of a polysiloxane film to organic vapours

Abstract: The sensitivity of polycyanopropylmethylsiloxane films to organic vapours has been investigated using electrical admittance spectroscopy. The films were exposed to benzene, ethanol and acetonitrile. In all cases, a reversible change in the capacitance and conductance of the polymeric film was observed. An analysis of the changes induced by the different vapours suggests that, with a judicious choice of measurement frequencies, conductance and capacitance data could provide an useful basis for a selective sensing system.