In this paper, a non-isothermal two-phase flow in the cathode gas diffusion layer (GDL) of PEM fuel cell is modeled. The governing equations including energy, mass and momentum conservation equations are solved by numerical methods. Also, the optimal values of the effective parameters such as the electrodes porosity, gas diffusion layer (GDL) thickness and inlet relative humidity are calculated...

Survival and growth of terrestrial plants is negatively affected by complete submergence. This is mainly the result of hampered gas exchange between plants and their environment, since gas diffusion is severely reduced in water compared with air, resulting in O2 deficits which limit aerobic respiration. The continuation of photosynthesis could probably alleviate submergence-stress in terrestria...

In the current work, we present a comprehensive modeling framework to predict the effective gas diffusivity, as a function of liquid water saturation, based on realistic 3-D microstructures of the uncompressed as well as compressed gas diffusion layer (GDL). The presented approach combines the generation of a virtual microscopic GDL and different physical modeling. We develop a reduced model in...

The diffusivities of methane in single-walled carbon nanotubes (SWNTs) are investigated at various temperatures and pressures using classical molecular dynamics (MD) simulations complemented with grand canonical Monte Carlo (GCMC) simulations. The carbon atoms at the nanotubes are structured according to the (m, m) armchair arrangement and the interactions between each methane molecule and all ...

We study diffusive transport of aqueous methane in sea sediments, which is important for formation of methane hydrate and gas deposits and has even been claimed to be principal methane transport mechanism for some geological systems. The isothermal diffusion law (Fick's law), D X = − ∇ J , which is employed in the literature for investigations on methane hydrate, is shown to significantly devia...

Various methods to determine 222Rn concentration in soil gas were tested at two sites with different soil types in a depth of 1 m. They include instantaneous (spot), continuous (real time) and timeaveraging procedures with advective ('active' procedures) or diffusive ('passive' procedures) gas transport from soil to detector: a) active grab-sampling of soil gas from different thin soil gas prob...

Solid-state nuclear track detectors (SSNTDs) in diffusion chambers have been routinely used for long-term measurements of radon gas concentrations. In usual practice, a filter is added across the top of the diffusion chamber to stop the progeny from entering. Thoron can also be deterred from entering the diffusion chamber by using a polyethylene (PE) membrane. However, the thickness of the PE m...

gas diffusion electrode was used for providing better conditions in fuel cell systems for oxygen reduction reaction (orr). because the slow kinetics of the oxygen reduction reaction at the proton exchange membrane fuel cell cathode restricts fuel cell efficiency. to this end, researchers have used platinum-coated carbon. in the present study, due to the reduction of carbon corrosion, zinc oxide...

Carbon molecular sieve membranes (CMSMs) have been considered as very promising candidates for gas separation, in terms of separation properties as well as thermal and chemical stability. Due to the numerous advantages and wide applications of carbon membranes, their application for gas separation is of special importance. Because of the importance of carbon membranes and a large number of stud...

Gas separation only became a major industrial application of membrane technology in the past 30 years, but the study of gas permeation through membranes has a long history. Systematic studies began with Thomas Graham who, over a period of 20 years, measured the permeation rates of all the gases then known, through every diaphragm available to him [1]. This was no small task because his experime...