Electrodeless discharge as detector in the rapid determination of binary diffusion coefficient of gases†

Arnikar, H. J.; Ghule, H. M.

doi:10.1080/00207216908938148

Cited by 12 publications

(8 citation statements)

References 4 publications

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“…The flux of isoprene from a leaf can be described by traditional models of diffusion as follows: uis = (Csi -CSO)gis (1) where Jls is the rate of isoprene efflux, C1si and Cs5, are the intercellular and ambient concentrations of isoprene, respectively, and gjs is the leaf conductance (stomatal plus boundary layer) to isoprene. Assuming that gis = gw(DIs/Dw) (2) where gw is the conductance to water vapor, and D1s and Dw are the diffusion coefficients for isoprene and water vapor in air, respectively, then Cisi = C1s5 + (Dw JIs/Dis gw).…”

Section: Determination Of Intercellular Isoprene Concentrationsmentioning

confidence: 99%

Isoprene Emission Rate and Intercellular Isoprene Concentration as Influenced by Stomatal Distribution and Conductance

Fall¹,

Monson²

1992

Plant Physiol.

155

106

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Isoprene emission in relation to stomatal distribution and con-ductance was determined for the hypostomatous species, aspen and white oak, and the amphistomatous species, cottonwood. For aspen and oak, isoprene emission from the adaxial (nonstomatal) surface was <2% of that from the abaxial (stomatal) surface, even when stomata were closed by addition of abscisic acid (ABA). When treated with ABA, the total flux rate of isoprene emission from leaves of these two hypostomatous species was unchanged, despite decreases in stomatal conductance of over 90%. The lack of control over isoprene emission rate by stomatal conductance, despite the apparent movement of isoprene through the stomatal pores, was due to increases in the intercellular isoprene concentration that compensated for the decreased stomatal conductance and restored the equilibrium between the isoprene synthesis rate and emission rate. This relationship was demonstrated by (a) an experiment in which the decrease in the internal isoprene pool following the imposition of darkness took longer in the presence of ABA than in its absence, and (b) direct measurements of the internal isoprene concentration through vacuum extraction, which revealed substantially higher values in the presence of ABA than in its absence. In the amphistomatous species, cottonwood, isoprene was emitted from both surfaces and addition of ABA caused an increase in isoprene emission from one surface coupled with a decrease from the other surface. The specific surface exhibiting an increase varied among leaves, with some leaves exhibiting an increase from the adaxial surface and other leaves from the abaxial surface. We interpret this as indicating nonuniform stomatal closure with con-comitant emission of isoprene at the greatest rate from the surface with the highest stomatal conductance. We also observed an increase in the total isoprene emission rate from cottonwood leaves following treatment with ABA. We interpret this as indicating a stimulation of isoprene synthesis in response to ABA or stomatal closure, with unknown cause. ance and a 70% reduction in photosynthetic CO2 assimilation rate (7). Tingey and coworkers (13) have also demonstrated that in water-stressed oaks, isoprene emission rate did not decline under conditions where leaf conductance declined substantially. Such results might be explained in two possible ways. First, when stomata close, isoprene emission might occur through the cuticle. Second, the synthesis rate of iso-prene might not be decreased by stomatal closure, resulting in a buildup of the intercellular isoprene concentration until the emission rate once again comes into equilibrium with the synthesis rate. Here we describe experiments designed to measure cuticular and stomatal transport of isoprene in an effort to distinguish between these two possibilities. There is evidence in the literature that isoprene is indeed emitted through stomatal pores. Tingey et al. (13) examined this issue using live oak leaves, where a glass cuvette was mounted on either the a...

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Section: Determination Of Intercellular Isoprene Concentrationsmentioning

confidence: 99%

Isoprene Emission Rate and Intercellular Isoprene Concentration as Influenced by Stomatal Distribution and Conductance

Fall¹,

Monson²

1992

Plant Physiol.

155

106

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“…6 and 7, respectively. In the same tables, the values of diffusion coefficients found in the present work, D found , and the corresponding literature values, D lit , either calculated by using the Fuller‐Schettler‐Giddings equation25 or experimentally obtained for the diffusivity of ethanol vapors in nitrogen, are also given 27. The accuracy of the method is determined as % deviation of the experimental values, D found , obtained by means of RF‐GC, from the respective literature ones, D lit .…”

Section: Resultsmentioning

confidence: 79%

“…The accuracy of the method is determined as % deviation of the experimental values, D found , obtained by means of RF‐GC, from the respective literature ones, D lit . The continuous elution GC method in a packed column was used for the determination of the experimental value for the diffusion coefficient of ethanol in nitrogen 27. The calculation of the diffusion coefficient was based on the van Deemter equation at low carrier gas flow rates while the accuracy of the D value was 2.8% 28…”

Section: Resultsmentioning

confidence: 99%

Study of the evaporation of pollutant liquids under the influence of surfactants

Gavril¹,

Atta²,

Karaiskakis³

2006

AIChE Journal

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“…The present method gives an alternative from the previous method [15], since the former method can be used in simultaneously determining the evaporation rates and diffusion rates of the liquid under study. The present method can be considered accurate since the results show that the diffusion in the current experiment deviates from the predicted theoretical value by less than 2.0% (based on mean values); as compared from the works by Anikar H.J.…”

Section: Discussionmentioning

confidence: 99%

“…RESULTS AND DISCUSSION Table I summarizes the results for the evaporation of methanol under the influence of the surfactant Triton X-100 ranging from 0 to 4 monolayers. The diffusion coefficients which are determined from this experiment were compared with the predicted values from the Fuller-Giddings equation [11] and experimentally obtained values from previous experimental work [15] which was using a different method. The uncertainty in the determination of the vaporization values, k c , varies from 0.2 to 2.5% in this case.…”

Section: Theoretical Basismentioning

confidence: 99%

Study the Effect of Imposing Surfactants toward the Evaporation of Low Molecular Weight Alcohol

Mohammad¹,

Zain²,

Rashid³

et al. 2013

IJESD

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Abstract-In thispaper, Reversed-Flow Gas Chromatography (RF-GC) is utilized to investigate the evaporation of low molecular weight alcohol. Evaporation rates as well as the diffusion rates of methanol are determined with a surfactant monolayer on the surface of the liquid; while nitrogen acts as carrier gas, at 313 K. The precision (>99.9%) and accuracy of this investigation demonstrates the potential of current methodologies for environmental impact studies; this is further verified when the results are compared with the available literature. The varying evaporation rates of methanol in the presence of varying amounts of Triton X-100 reflects that application of surfactants do damper the evaporation rates of liquid pollutants; without interference with the former's diffusion coefficients. High amounts of Triton X-100 are required for retardation of evaporation rates, suggesting the formation of a densely packed surface monolayer or the formation of an insoluble monolayer.

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Electrodeless discharge as detector in the rapid determination of binary diffusion coefficient of gases†

Cited by 12 publications

References 4 publications

Isoprene Emission Rate and Intercellular Isoprene Concentration as Influenced by Stomatal Distribution and Conductance

Isoprene Emission Rate and Intercellular Isoprene Concentration as Influenced by Stomatal Distribution and Conductance

Study of the evaporation of pollutant liquids under the influence of surfactants

Study the Effect of Imposing Surfactants toward the Evaporation of Low Molecular Weight Alcohol

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