Showing papers by "Hamid Garmestani published in 2003"
TL;DR: In this paper, the thermal and electrical properties of single wall carbon nanotube (CNT)-polymer composites are significantly enhanced by magnetic alignment during processing, and the electrical transport properties are mainly governed by the hopping conduction with localization lengths comparable to bundle diameters.
Abstract: We show that the thermal and electrical properties of single wall carbon nanotube (CNT)-polymer composites are significantly enhanced by magnetic alignment during processing. The electrical transport properties of the composites are mainly governed by the hopping conduction with localization lengths comparable to bundle diameters. The bundling of nanotubes during the composite processing is an important factor for electrical, and in particular, for thermal transport properties. Better CNT isolation will be needed to reach the theoretical thermal conductivity limit for CNT composites.
542 citations
173 citations
TL;DR: Temper cold rolled silicon steel samples were annealed with and without an applied magnetic field as mentioned in this paper, and the final grain size was the same for both annealing conditions.
57 citations
TL;DR: In this article, a bicrystal of Zn with an originally flat 89° 〈1010〉 symmetric tilt boundary was annealed in a magnetic field of 25 T. The boundary migrated under the action of a magnetic driving force in the direction of the grain with higher diamagnetic susceptibility.
Abstract: A bicrystal of Zn with an originally flat 89° 〈1010〉 symmetric tilt boundary was annealed in a magnetic field of 25 T. The boundary migrated under the action of a magnetic driving force in the direction of the grain with higher diamagnetic susceptibility. In addition, the boundary changed its crystallographic orientation, decreasing length and becoming almost perpendicular to the free surfaces. The results were interpreted in terms of magnetically forced grain boundary motion due to the anisotropy of the magnetic susceptibility in Zn. The absolute boundary mobility was measured to be about 5.1×10−9 m4/J s.
49 citations
TL;DR: In this article, the magnetic and capillarity-driven boundary migration was measured to be about 2:5 � 10 � 8 m 4 /J s. Boundaries migrate reorienting almost perpendicular to the free surfaces.
41 citations
TL;DR: In this paper, a general methodology is developed to model the texture evolution of polycrystalline materials during mechanical processing, based on the conservation of texture volume as proposed by Bunge.
39 citations
TL;DR: In this paper, the evolution of the texture of high-density polyethylene (HDPE) and ethylene-1-octene copolymer prepared with a Ziegler-Natta catalyst was studied during tensile deformation using wide-angle X-ray diffraction WAXD.
26 citations
TL;DR: In this paper, it was found that the reduction in the exchange coupling greatly reduces the nucleation field HN of the soft layer and increases the irreversible switching field Hirr of the hard layer.
Abstract: Magnetically soft/hard exchange-coupled Ni80Fe20/Si3N4/Sm40Fe60 and Ni80Fe20/mixture/Sm40Fe60 layered structures with induced in-plane uniaxial anisotropy were deposited by sputtering on Si (100) substrates. The interfacial exchange coupling strength between the soft and hard layers was tailored by inserting a thin nonmagnetic insulating Si3N4 layer or by varying interfacial mixture of NiFe and SmFe. It was found that the reduction in the exchange coupling greatly reduces the nucleation field HN of the soft layer and increases the irreversible switching field Hirr of the hard layer. The simple formula used before to describe the nucleation field of the soft layer does not work in the case of the reduced interfacial exchange coupling.
20 citations
TL;DR: The present study demonstrates for the first time the feasibility of introducing the TN method, with quadratic convergence rate, to the field of neural networks, and provides comparative experimental results and explicit model results to verify the effectiveness of the neural networks-based model.
20 citations
TL;DR: In this paper, the effect of varying these parameters on the mechanical strength of the 7249 aluminum alloy has been studied and the most critical step in this process has been identified as quenching.
11 citations
TL;DR: In this paper, the influence of intragranular slip on grain boundary sliding is studied in originally compatible zinc bicrystals with symmetric tilt boundary and a good correlation between the boundary sliding and intragraneular slip prior to slide hardening is established.
Abstract: The influence of intragranular slip on grain boundary sliding is studied in originally compatible zinc bicrystals with symmetric tilt boundary. The experiment is designed to separate different effects of intragranular slip on the boundary sliding and establish their mechanisms. Grain boundary sliding with and without development of intragranular slip is observed. The rate of sliding accompanied by slip is more than five times of that without slip. A good correlation between the boundary sliding and intragranular slip prior to slide hardening is established. Slide hardening followed by the negative sliding near one end of the boundary and strain hardening in the boundary vicinity, are observed at the last stages of deformation. For the case of formation of slip induced glissile grain boundary dislocations of opposite signs the possibility of their contribution to total grain boundary sliding, is analyzed. The effect of the increase in the rate of sliding is explained in terms of the accommodation of sliding by slip and appearance of additional glissile grain boundary dislocations of one sign due to strain incompatibility. Contribution of these different dislocation mechanisms to the increase in the sliding rate is determined for the stage of deformation preceding slide hardening. It is supposed that the effect of slide hardening and negative sliding as well as boundary curving is created by non-smooth boundary and small degree of incompatibility caused by straining.