Vapours

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

On The Spectra Of Ignited Gases And Vapours: With Especial Regard To The Different Spectra Of The Same Elementary Gaseous Substance...

Abstract: 1. In order to obtain the spectra of all the elementary bodies, you may make use either of flame or the electric current. For this purpose flame is preferable on account of its easy management, and therefore was immediately introduced into the laboratory of the chemist. But its use is rather limited, the metals of alkalies being nearly the only substances which, if introduced into flame, give spectra exhibiting well-defined bright lines. In the case of the greater number of elementary substances the temperature of flame, even if alimented by oxygen instead of air, is too low. Either these substances are not reduced into vapour by means of flame, or, if reduced, the vapour does not reach the temperature necessary to render it luminous in such a degree that by prismatic analysis we obtain its characteristic rays. The electric current, the heating power of which may be indefinitely increased by increasing its intensity, is alone fitted to produce the peculiar spectra of all elementary bodies. 2. In applying the electric current we may proceed in two ways. In one mode of proceeding the substance to be examined by its spectrum is at the same time, by means of the current, transformed into vapour and rendered luminous. In the other mode the substance is either in the gaseous state, or, if not, has been converted into it by means of a lamp, and the electric current ignites the substance in passing through.

Effect of surfactant and oil additions in the biodegradation of hexane and toluene vapours in batch tests

Abstract: The biological treatment of gaseous emissions of hydrophobic volatile organic compounds (VOCs) results in low rates of elimination partially because of the low solubility of VOCs in water. Recently, the use of two‐phase partition bioreactors (TPPBs) was proposed to increase the bioavailability and consequently the elimination capacities of this kind of VOC. In the present study, TPPBs operating in a batch feed mode were tested for biodegradation of hexane and toluene vapours with a microbial consortium. The results obtained were compared with single‐phase systems (control experiments). The liquid phase used was silicone oil (organic phase) with the surfactant Pluronic F‐68. Experiments were named F1 and F2 for one and two phases, respectively, and F1S and F2S when the surfactant was included. The maximum specific rates (Srates) of hydrocarbon consumption for hexane and toluene were 539 and 773 mghydrocarbon/(gprotein·h), respectively. For both substrates, the systems that showed the highest Srates of hydr...

Ethanol and LPG sensing characteristics of SnO2 activated Cr2O3 thick film sensor

Abstract: The sensing response of pure and SnO2 activated Cr2O3 to ethanol vapours and liquefied petroleum gas (LPG) has been investigated. Fine particles of commercial chromium oxide powder were selected and deposited as thick film to act as a gas sensor. The sensor surface has been activated by tin dioxide, on surface oxidation of tin chloride. The concentration of tin chloride solution, used as activator, was varied from 0 to 5% and its effect on gas response, selectivity and operating temperature has been studied. It was found that response to ethanol vapours significantly improved, whereas response to LPG remained unaffected. Moreover, operating temperature remains unchanged both for LPG and ethanol vapours.

Organic acid vapours and their effect on corrosion of copper : a review

Abstract: Carboxylic acids of low molecular weight, such as formic, acetic, propionic and butyric acids, as well as other acids (n-pentanoic, hexanoic, heptanoic, etc.), are present in rain, snow, clouds and particulate matter. They contribute about 16–36% of rain acidity. It is estimated that ∼64% of formic acid and ∼88% of acetic acid are in the vapour phase. Carboxylic acids are produced by the combustion of biomass, and analyses of the smoke from fire events reveal concentrations of about 300–500 ppb for formic acid and 3000–5000 ppb for acetic acid. Industrial emissions of carboxylic acid are produced by plants processing biological materials, such as food, paper, wood, etc. Acetic acid vapours are found in several industrial atmospheres. Vinegar is one important source of acetic acid vapours in food processing plants. The present review shows that for copper specimens exposed to organic vapours for 21 days at 100% relative humidity (RH) and a contaminant level in the range of 10–300 ppm, the relative...