scaling challenges and limitations of conventional silicon transistors have led the designers to apply novel nano-technologies. one of the most promising and possible nano-technologies is cnt (carbon nanotube) based transistors. cnfet have emerged as the more practicable and promising alternative device compared to the other nanotechnologies.  this technology has higher efficiency compared to t...

background: motorcycle accidents and sport accidents lead yearly to many head injuries like head fractures and concussion. so finding the most proper helmet for reducing the injuries to head can be very helpful for head protection in such cases. methods: after 3d modeling of the helmet and head and meshing the model, a compressive impacting load of 1.31mpa was exerted on head and the model was ...

A transient _nite element analysis is carried out to provide insight into the low temperature dynamic material toughness versus crack tip relationship for high strength structural steels under intense stress pulse loading[ The problem analyzed here is plane strain fracture of an edge cracked specimen under plane wave loading conditions[ The _nite element formulation employed accounts for the e}...

We study three-dimensional finite transient deformations of transparent poly-methyl-methacrylate (PMMA)/adhesive/polycarbonate (PC) laminates impacted at low speed by a hemispherical nosed rigid cylinder using the commercial finite element (FE) software LS-DYNA. The two glassy polymers PMMA and PC are modeled as thermo-elasto-visco-plastic materials by using the constitutive relation proposed b...

Background Walking speed is one of the best measures of overall walking ability. In plantar pressure measurements, walking speed is usually assessed using a stopwatch, photocells, or camera systems. As a simple alternative, contact time can be used but contact time and walking speed are only moderately correlated. Because walking speeds alters foot loading, the centre of pressure might be of mo...

Wind turbines in a wind farm, influence each other through the wind flow. Downwind turbines are in the wake of upwind turbines and the wind speed experienced at downwind turbines is hence a function of the wind speeds at upwind turbines but also the momentum extracted from the wind by the upwind turbine. This paper establishes flow models relating the wind speeds at turbines in a farm. So far, ...

Polycrystalline Diamond (PCD) Cutters are ultra-hard tools used for oil and gas drilling. These can fail in the form of spalling due to impact. In this paper, direct impact quasi-static loading investigate failure force leached PCD cutters when loaded at an angle on edge their chamfer with a striker or platen. Impact experiments were performed using impedance match system which ensures sample i...