Showing papers on "Vapours published in 2002"
TL;DR: It is shown, to the knowledge for the first time, that these newly formed particles are composed primarily of organic species, such as cis-pinonic acid and pinic acid, produced by oxidation of terpenes in organic vapours released from the canopy.
Abstract: Aerosol particles produced over forested areas may affect climate by acting as nuclei for cloud condensation, but their composition (and hence the chemical species that drive their production) remains an open question. Here we show, to our knowledge for the first time, that these newly formed particles (3–5 nm in diameter) are composed primarily of organic species, such as cis-pinonic acid and pinic acid, produced by oxidation of terpenes in organic vapours released from the canopy1,2,3,4.
421 citations
TL;DR: In this article, the surface diffusion of strongly adsorbing hydrocarbon vapours on activated carbon was measured by using a constant molar flow method, where pure adsorbate is introduced into a semi-batch adsorber at a constant flow rate.
32 citations
TL;DR: Two microcalorimetric methods, one for the simultaneous measurement of adsorption isotherm and enthalpy and the other for the determination of wetting or immersion energy, are described in this paper.
Abstract: The interaction of a powder with vapours or their wettability by liquids are involved in many industrial processes and then needs to be studied by simple and reproducible methods. Two microcalorimetric methods, one for the simultaneous measurement of adsorption isotherm and enthalpy and the other for the determination of wetting or immersion energy, are described. A few examples are given for the adsorption and wetting of powders by water and organic vapours.
23 citations
TL;DR: Agranovski et al. as mentioned in this paper used sunflower oil as the irrigating fluid for removing organic particles and vapours from an air carrier and found that the filtration efficiencies of the oil are better than for water, for liquid di-ethyl-hexyl-sebacate particles.
6 citations
TL;DR: In this paper, an intrinsically low conductive membrane of the calix[4]resorcinarene [C7H15] derivative with a charge flow transistor was used to detect reversibly high concentrations of organic vapours in air.
Abstract: A novel method to detect reversibly high concentrations of organic vapours in air has been developed by combining an intrinsically low conductive membrane of the calix[4]resorcinarene [C7H15] derivative with a charge flow transistor. The modulation of the turn-on response for the transistor upon exposure to acetone, chloroform, methanol, hexane and water is presented. The increase in the membrane conductivity is partially attributed to condensation of the vapours in the highly microporous membrane even below the saturation vapour pressure and partially to the effect of the polar analyte molecules complexing inside and between the OH groups of the cavities. The observed sensitivity is in the order chloroform >> acetone >> methanol >> hexane >> water.
5 citations
01 Jan 2002
5 citations
01 Jan 2002
TL;DR: In this article, conditions under which vapours condense into small pores and the requisite adsorbent properties are discussed and experimental results for several vapours and adsorbents are presented.
Abstract: Condensation of vapours into mesoporous adsorbents occurs spontaneously at pressures less than their saturation vapour pressure. The thermophysical properties of the resulting capillary liquids, density, thermal expansivity, isothermal compressibility and heat capacity are similar to those of the corresponding bulk liquid. However, the liquid-vapour interface may be highly curved resulting in a large tension or negative pressure within the capillary liquid. Since the liquid is thermodynamically stable, homogenous nucleation of the vapour phase is suppressed but increasing the tension may eventually lead to its rupture by spinodal decomposition. Conditions under which vapours condense into small pores and the requisite adsorbent properties will be discussed. Experimental results for several vapours and adsorbents will be presented.
2 citations
TL;DR: In this paper, the heat, equilibrium, and kinetics of 1-ethoxy-2-propanol vapours on granulated activated carbon were determined simultaneously by a reaction calorimeter SETARAM C80 D at T=298.15 K at various relative vapour pressures (0.1 < p/ps<0.8).
Abstract: The heat, equilibrium, and kinetics of adsorption of 1-ethoxy-2-propanol vapours on granulated activated carbon were determined simultaneously by a reaction calorimeter SETARAM C80 D at T=298.15 K at various relative vapour pressures (0.1< p/ps<0.8). The adsorption isotherm was correlated by the Freundlich equation. It was observed that the enthalpies of adsorption decrease slightly with increasing of the relative vapour pressure of the adsorptive. The rate of adsorption were calculated from analysis of the heat flux signals and it was found that the mass-transfer coefficient for 1-ethoxy-2-propanol vapours in granulated activated carbon increased with increasing relative vapour pressure of the adsorptive.
2 citations
Patent•
01 Jul 2002
TL;DR: In this article, the authors describe a process and device for the treatment of vapours emitted during the pumping of liquids containing inflammable and/or malodorous and toxic volatile compounds, in the course of cleaning operations or during a filling operation, in particular using extractor-hydrowashers.
Abstract: Process and device for the treatment of vapours emitted during the pumping of liquids containing inflammable and/or malodorous and/or toxic volatile compounds, in the course of cleaning operations or during a filling operation, in particular using extractor-hydrowashers. The process is characterised in that, before it is discharged into the atmosphere, the stream to be treated is passed through at least one purification device (9) where the volatile compounds present therein are adsorbed on a support based on fibres of activated carbon.
19 Dec 2002
TL;DR: A bulk acoustic sensor system was fabricated to detect organic vapours of toluene, benzene, hexane and cyclohexane using Langmuir Blodgett thin film deposited on a quartz crystal and found that the thin film was sensitive to the present of gases by reducing the crystal frequency.
Abstract: A bulk acoustic sensor system was fabricated to detect organic vapours of toluene, benzene, hexane and cyclohexane. The system consists of Langmuir Blodgett thin film deposited on a quartz crystal. The sensing sensitivity was based on the changes of the fundamental frequency of the quartz crystal upon exposure toward vapours. It was found that the thin film was sensitive to the present of gases by reducing the crystal frequency as high as 13 Hz, 8 Hz, 4 Hz, and 3 Hz for toluene, benzene, hexane and cyclohexane respectively. The response time to reach the maximum changes on the frequency was within 200 seconds. The recovery time after the vapors removed from the system was within 200 seconds. The variation of response with the type of vapours may be used as selectivity criteria for the sensor.