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...

within the effective-field theory with correlations (eft), a transverse random field spin-1 ising model on the simple cubic (z=6) lattice is studied. the phase diagrams, the behavior of critical points, transverse magnetization,  internal energy, magnetic specific heat are obtained numerically and discussed for different values of p the concentration of the random transverse field.

background: previous studies reported that neonatal and maternal complications as well as duration of labor could be diminished through labor management. therefore, we aimed to evaluate the effect of intramuscular (im) administration of atropine and hyoscine combination on labor progress and maternal and neonatal outcomes in primigravid women admitted to taleghani hospital of arak, iran. method...

flow regime in dam's bottom outlet is divided in pressurized flow and free surface flow by the gate located for discharge control. down stream tunnel involves high velocity multi component air –water flow studied by mathematical model. in this research work, we used finite volume mixture two phase flow model. because of high reynolds number, standard two equations k-e turbulence model was ...

rock chutes are natural river training structures and are efficient energy dissipaters too. from the hydraulic and environmental point of view, rock chutes have become important structures in the natural river morphology. a physical study was conducted and flow properties were measured over rough bed materials of a rock chute, which was assembled at the pitlab center of the university of pisa, ...

in this article, vehicle cornering stability and brake stabilization via bifurcation analysis has been investigated. in order to extract the governing equations of motion, a nonlinear four-wheeled vehicle model with two degrees of freedom has been developed. using the continuation software package matcont a stability analysis based on phase plane analysis and bifurcation of equilibrium is perfo...

polycyclic aromatic hydrocarbons (pahs) are toxic pollutants released by various urban combustion sources. tehran is the largest city in iran with a population of about 8 million and it is faced with serious air quality problems. the gas phase samples collected from 21 sites in tehran area throughout year 2005. the samples‘ pahs were collected using a skc trapping consisting of glass cartridg...

ethylene was polymerized in slurry phase over a ticl4/mg(oc2h5)2 catalyst activated by al(c2h5)3. it was shown experimentally that mass transfer resistance has no effect on polymerization kinetics. after estimation ofthe active site concentration by inhibition method with carbon monoxide, the effects of polymerization temperature, monomer and cocatalyst  oncentrations and hydrogen were investig...

the effect of ferrite grain size on the fatigue and tensile properties of dual phase steels with a 0.25 volumefraction of martensite (vm) under different heat treatments was investigated. the heat treatments werehomogenized at 1200 oc along with several subsequent normalizations at 910 oc, resulting in differentmicrostructures and mechanical properties. after heat treatment, the obtained steels...

this paper reports the synthesis of polypyrrole coated sno2/znoelectrospunnanofibers via vapor phase polymerization method. in order to prepare one dimensional (sno2-zno)/polypyrrole with the core sheath structure, first sno2-zno composite nanofibers were synthesized via electrospinning method followed by adsorption of fe3+ on the surface of the sno2-zno nanofibers and finally pyrrole was polym...