comIn the present study, CO2 removal from natural gas stream has been studied using a flat sheet membrane contactor. A three dimensional mathematical model is developed to describe the process. The model considers the transport of a gas mixture containing carbon dioxide and methane through a flat sheet membrane contactor module. The model is based on the non-wetted mode of operation, in which t...

This paper focuses on a hydraulic radius separation approach used to calculate the boundary shear stress in terms of bed and wall shear stress proposed in a trapezoidal channel. The average bed and sidewall shear stress in smooth trapezoidal open channels are derived after using Guo & Julien (2005) early equations taking a part of an investigation to cover both rectangular and trapezoidal chann...

The performances of two-phase polymer-liquid PEBAX®/polyethylene glycol (PEG) and three-phase polymer-liquid-solid PEBAX®/PEG/MWNT thin film composite membranes for CO2 and CH4 permeation were studied. The effect of temperature and MWNT/PEBAX® ratio on single gas (CO2 and CH4) permeability was investigated. The permeat...

We propose a simple phenomenological model for wet granular media to take into account many particle interaction through liquid in the funicular state as well as two-body cohesive force by a liquid bridge in the pendular state. In the wet granular media with small liquid content, liquid forms a bridge at each contact point, which induces two-body cohesive force due to the surface tension. As th...

Molecular dynamics simulations are used to investigate the influence of molecular-scale surface roughness on the slip behavior in thin liquid films. The slip length increases almost linearly with the shear rate for atomically smooth rigid walls and incommensurate structures of the liquid/solid interface. The thermal fluctuations of the wall atoms lead to an effective surface roughness, which ma...

The performances of two-phase polymer-liquid PEBAX®/polyethylene glycol (PEG) and three-phase polymer-liquid-solid PEBAX®/PEG/MWNT thin film composite membranes for CO2 and CH4 permeation were studied. The effect of temperature and MWNT/PEBAX® ratio on single gas (CO2 and CH4) permeability was investigated. The permeat...

Minimizing the retarding force on a solid moving in liquid is the canonical problem in the quest for energy saving by friction and drag reduction. For an ideal object that cannot sustain any shear stress on its surface, theory predicts that drag force will fall to zero as its speed becomes large. However, experimental verification of this prediction has been challenging. We report the construct...

In the article by Angunawela et al. in the September 2011 issue, the authors used the finite-volume method and advanced computational fluid dynamic modeling to replicate a vitrectomized eye filled with gas tamponade. They computed the relationship between different fractions of gas fill and fluid shear stress on the retina in response to saccadic eye movements and rectilinear head movements and...