In present work, numerical analysis of three novel PEM fuel cells with tubular geometry was conducted. Tree different cross section was considered for PEM, namely: circular, square and triangular. Similar boundary and operational conditions is applied for all the geometries. At first, the obtained polarization curve for basic architecture fuel cells was validated with experimental data and then...

assessing the behavior of composite structures which are subjected to impact loads is one of the important subjects in the field of mechanical sciences. using thin-walled tubes which collapsed and absorbed the impact energy is a well-known method to prevent damages to the other parts of the structures. in this paper, deformations, crushing length, peak load, mean force and energy absorption cap...

one of the most important discharge control ways in hydraulic structures is side weir which is used in irrigation, water distribution, waste-water engineering, drainage, flood control and other water related projects.in order to increases cm value and control on water surface when there is restriction in the weir length(l), side weir with different geometry is used. in present research seventhl...

because of production process and constrains conditions, circular graphene sheet may be opposed to structural defect and pin hole, respectively. some of the defects and pin hole on a circular graphene sheet can be considered as an eccentric hole on the sheet. hence, analyzing behavior of circular graphene sheet with an eccentric hole is important. free vibration of an eccentric annular graphene...

the momentum equation in the kinematic wave model is a power-law equation with two parameters. these parameters, which relate the discharge to the flow area, are commonly derived using manning’s equation. in general, the values of these parameters depend on the flow depth except for some special cross sections. in this paper, improved estimates of the kinematic wave parameters for circular chan...

A mean field model of ferromagnetism mediated by delocalized or weakly localized holes in zincblende and wurzite diluted magnetic semiconductors is presented. The model takes into account: (i) strong spin-orbit and kp couplings in the valence band; (ii) the effect of strain upon the hole density-of-states, and (iii) the influence of disorder and carrier-carrier interactions, particularly near t...

Circular dichroism (CD) spectroscopy is by far the most widely used technique for protein secondary structure analysis. A survey of the scientific literature will reveal that Robert Woody (Fig. 1) has undoubtedly been a pioneer in the elucidation of the relationship between CD and protein structure and