Surface water ethylene concentrations

Figure 2. Surface water ethylene concentrations (O) of USNS Hayes cruise (Hawaii to Tahiti, Table II). Daily averages of chlorophyll a concentrations,...

We have developed a compact photocatalytic reactor [1], which enables efficient decomposition of organic carbons in a gas or a liquid phase, incorporating a flexible and light-dispersive wire-net coated with titanium dioxide. Ethylene was selected as a model compound which would rot plants in sealed space when emitted. Effects of the titanium dioxide loading, the ethylene concentration, and the humidity were examined in batches. Kinetic analysis elucidated that the surface reaction of adsorbed ethylene could be regarded as a controlling step under the experimental conditions studied, assuming the competitive adsorption of ethylene and water molecules on the same active site. 

Kinetic analysis based on the Langmuir-Hinshelwood model was performed on the assumption that ethylene and water vapor molecules were adsorbed on the same active site competitively [2]. We assumed then that overall photocatalytic decomposition rate was controlled by the surface reaction of adsorbed ethylene. Under the water vapor concentration from 10,200 to 28,300ppm, and the ethylene concentration from 30 to 100 ppm, the reaction rate equation can be represented by Eq.(l), based on the fitting procedure of 1/r vs. 1/ Ccm ... 

Figure 23.7 Change of the concentration of O atom near the top surface of ethylene-vinyl alcohol copolymer film as a function of water immersion time.

Figiure 2 shows the ethylene (C2H4) concentrations in the surface waters between Hawaii and Tahiti (Table II). Excluding the values obtained just outside Hawaii (3/21/74) and Tahiti (3/29/74), a broad general increase is apparent with a maximum average value of 4.0 X 10 ml/1 and a low average value of 2.4 X 10 ml/1. Plotted over... 

The last example deals with submerged Rumex species. A hypoxic atmosphere thus exists in the tissue because gas diffusion is limited in water. In contrast to Rumex acetosuy Rumex palustris shows stimulated shoot elongation in response to submergence paralleled and triggered by drastic enhancement of ethylene concentration. This elongation response is functionally related to the opportunity to reach better illuminated and aerated zones close to the water surface or preferentially above it (Voesenek and van der Veen 1994). Desubmergence of the species displays a first peak in ethylene emission with a subsequent second rise followed by a slow decay (Fig. 10). As discussed by Voesenek et al. (1993), the first peak is due to release of entrapped ethylene. The second rise corresponds to a temporary... 

The general impression is of a widespread distribution, at the pg/1 level, of chloroform, carbon tetrachloride, trichloroethylene, perchloroethylene and methyl chloroform methyl chloride, vinyl chloride and ethylene dichloride are virtually absent, despite the large quantity of each known to be produced while methylene chloride is reported locally, and such compounds as hexachlorobutadiene at very low levels only in waters known to be affected by production effluents. There is, nevertheless, a very wide variation about these typical values, of at least 3 orders of magnitude it is difficult, therefore, to quote fully representative levels. Surface waters provide a much lower potential for widespread mixing than does the atmosphere, where concentrations of constituents are much more consistent. Many surface waters also contain the 3 brominated THMs these are probably derived from discharges of chlorinated potable water after use. 

A drilling fluid additive, which acts as a clay stabilizer, is the reaction product of methylglucoside and alkylene oxides such as ethylene oxide, propylene oxide, or butylene oxide. Such an additive is soluble in water at ambient conditions, but becomes insoluble at elevated down-hole temperatures [386], Because of their insolubility at elevated temperatures, these compounds concentrate at important surfaces such as the drill bit cutting surface, the borehole surface, and the surfaces of the drilled cuttings. 

However, in the case of Na tetradecyl dioxy-ethylene sulfate, the surface tension and the critical micelle concentration will be reduced in the presence of water hardness. If a complexing agent is added, the effect is weakened because of the complexing of the... 

Fig. 4 gives the results for experiments in which all of the water used contained surfactant at a concentration of 0.02% (w/v). Under these operating conditions, maximal extraction occurred with surfactant containing 15—20 mol% ethylene oxide. This corresponds to an HLB of 7.6—8.0. The maximum value obtained was 22% of the total bitumen in the surface fraction (Makon 20). Fig. 5 gives the results for experiements in which"all the surfactant was added in a small volume of water at the beginning of the process, resulting in a much higher initial... 

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