Gas Diffusivity

2018 ◽  
pp. 1089-1102 ◽  
Author(s):  
D. E. Rolston
Keyword(s):  
Gas Diffusivity

scholarly journals Irrigation Scheduling with Soil Gas Diffusivity as a Decision Tool to Mitigate N2O Emissions from a Urine-Affected Pasture

Agriculture ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 443
Author(s):  
Camille Rousset ◽  
Timothy J. Clough ◽  
Peter R. Grace ◽  
David W. Rowlings ◽  
Clemens Scheer
Keyword(s):  
Irrigation Management ◽  
Irrigation Treatment ◽  
Irrigation Scheduling ◽  
Soil Gas ◽  
N2o Emissions ◽  
Irrigation Frequency ◽  
Water Demands ◽  
Gas Diffusivity ◽  
Matter Production ◽  
Access To Water

Pastures require year-round access to water and in some locations rely on irrigation during dry periods. Currently, there is a dearth of knowledge about the potential for using irrigation to mitigate N2O emissions. This study aimed to mitigate N2O losses from intensely managed pastures by adjusting irrigation frequency using soil gas diffusivity (Dp/Do) thresholds. Two irrigation regimes were compared; a standard irrigation treatment based on farmer practice (15 mm applied every 3 days) versus an optimised irrigation treatment where irrigation was applied when soil Dp/Do was ≈0.033 (equivalent to 50% of plant available water). Cow urine was applied at a rate of 700 kg N ha−1 to simulate a ruminant urine deposition event. In addition to N2O fluxes, soil moisture content was monitored hourly, Dp/Do was modelled, and pasture dry matter production was measured. Standard irrigation practices resulted in higher (p = 0.09) cumulative N2O emissions than the optimised irrigation treatment. Pasture growth rates under treatments did not differ. Denitrification during re-wetting events (irrigation and rain) contributed to soil N2O emissions. These results warrant further modelling of irrigation management as a mitigation option for N2O emissions from pasture soils, based on Dp/Do thresholds, rainfall, plant water demands and evapotranspiration.

Measurement of Gas Diffusivity In Heavy Oils

10.2118/98-63 ◽  
1998 ◽  
Author(s):  
Y. Zhang ◽  
C.L. Hyndman ◽  
B. Maini
Keyword(s):  
Heavy Oils ◽  
Gas Diffusivity

Impact of micro-scale heterogeneity on gas diffusivity of organic-rich shale matrix

2017 ◽  
Vol 45 ◽  
pp. 75-87 ◽  
Author(s):  
Feng Gao ◽  
Jia Liu ◽  
J.G. Wang ◽  
Yang Ju ◽  
Chun Fai Leung
Keyword(s):  
Micro Scale ◽  
Gas Diffusivity ◽  
Scale Heterogeneity

scholarly journals Thermodynamic Route to Efficient Prediction of Gas Diffusivity in Nanoporous Materials

Langmuir ◽  
2017 ◽  
Vol 33 (42) ◽  
pp. 11797-11803 ◽  
Author(s):  
Yun Tian ◽  
Xiaofei Xu ◽  
Jianzhong Wu
Keyword(s):  
Nanoporous Materials ◽  
Gas Diffusivity ◽  
Efficient Prediction

Generalized Density-Corrected Model for Gas Diffusivity in Variably Saturated Soils

2011 ◽  
Vol 75 (4) ◽  
pp. 1315-1329 ◽  
Author(s):  
T.K.K. Chamindu Deepagoda ◽  
Per Moldrup ◽  
Per Schjønning ◽  
Ken Kawamoto ◽  
Toshiko Komatsu ◽  
...  
Keyword(s):  
Saturated Soils ◽  
Gas Diffusivity

Effect of altered gas diffusivity on alveolar gas exchange-a theoretical study

1980 ◽  
Vol 48 (1) ◽  
pp. 147-153 ◽  
Author(s):  
W. Nixon ◽  
A. Pack
Keyword(s):  
Blood Flow ◽  
Gas Exchange ◽  
Theoretical Study ◽  
Experimental Studies ◽  
Flow Distribution ◽  
Molecular Diffusivity ◽  
Gas Diffusivity ◽  
Experimental Findings ◽  
Lung Airways ◽  
Alveolar Gas Exchange

Experimental studies have established that alveolar gas exchange is inversely relation to the molecular diffusivity of gas in the lung airways. The mechanism underlying this relationship is, however, unclear. To investigate this phenomenon, the conditions relevant to the experimental studies are simulated using a computational model of pulmonary gas transport. Results from these simulations suggest that the inverse relationship found experimentally can largely be explained on the basis of the intra-acinar stratification of blood flow and gas concentrations. Gas having a relatively low molecular diffusivity is not transported as far into the acinus as gas having a higher diffusivity. When these relative intra-acinar gas distributions interact with the blood flow distribution, which has been shown experimentally to be weighted towards the proximal alveoli, more gas exchange occurs in the low molecular diffusivity mixture. Consideration of the various other mechanisms that have been proposed to explain the experimental findings.he inverse dependence suggests that they are of little significance. In particular, our studies remove the need to invoke Taylor diffusion to explain the experimental findings.

scholarly journals Phenomenological Over-Parameterization of the Triple-Fitting-Parameter Diffusion Models in Evaluation of Gas Diffusion in Coal

Processes ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 241 ◽  
Author(s):  
Zang ◽  
Wang ◽  
Liu
Keyword(s):  
Curve Fitting ◽  
Gas Diffusion ◽  
Diffusion Models ◽  
The Other ◽  
Excellent Performance ◽  
Sorption Data ◽  
Gas Diffusivity ◽  
The Future ◽  
Manometric Method ◽  
Fitting Parameters

Gas diffusivities of coal are not measured directly but are normally regressed by fitting mathematical diffusion models to fractional sorption data measured in sorption experiments. This paper firstly measured three fractional adsorption curves at various equilibrium pressures with the manometric method. The measured fractional adsorption curves were then modeled with one single-fitting-parameter (SFP) model and three triple-fitting-parameter (TFP) models. The modeling results showed that the TFP models were phenomenologically over-parameterized due to the usage of three fitting parameters, which may be excessive for curve fitting. The phenomenological over-parameterization resulted in multiple pressure-dependences of gas diffusivity for the TFP models. The TFP models should thus be carefully used. On the other hand, the dual-fitting-parameter (DFP) models also have excellent performance in curve fitting and can produce interpretable modeling results. The DFP models can be used as an alternative to the TFP model in the future.

scholarly journals How respiratory gas diffusivity correlates with porosity of plant organ tissues

2019 ◽  
Vol 355 ◽  
pp. 012052
Author(s):  
B Nugraha ◽  
P Verboven ◽  
S Janssen ◽  
B Nicolaï
Keyword(s):  
Gas Diffusivity ◽  
Plant Organ

Gas Diffusivity in Undisturbed Volcanic Ash Soils

2003 ◽  
Vol 67 (1) ◽  
pp. 41-51 ◽  
Author(s):  
Per Moldrup ◽  
Seiko Yoshikawa ◽  
Torben Olesen ◽  
Toshiko Komatsu ◽  
Dennis E. Rolston
Keyword(s):  
Volcanic Ash ◽  
Gas Diffusivity ◽  
Volcanic Ash Soils
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