47,514 research outputs found
Auto-regulating New Media
Full text linkUsing Foucault's (1977, 1978) notion of panoptic method of governmentality and looking at the case of Singapore's Internet policy, this paper attempts to expand on the idea-and ideals-of 'auto-regulation'(Lee, 2000, pp. 4-5; Lee & Birch, 2000). Auto-regulation, as I shall posit in this paper, provides a way for regulatory enforcement and surveillance to become sufficiently transparent and 'normalised' so that 'the exercise of power may be supervised by society as a whole'(Foucault, 1977, pp.207-208) rather than by a select group of policy and law enforcement officers, or civil society /activist groups
Interlaminar fracture toughness and associated fracture behaviour of bead-filled epoxy/glass fibre hybrid composites
No full textTo investigate enhancement of matrix-dominated properties (such as interlaminar fracture toughness) of a composite laminate, two different bead-filled epoxies were used as matrices for the bead-filled epoxy/glass fibre hybrid composites. The plane strain fracture toughness of two different bead-filled epoxies have been measured using compact tension specimens. Significant increases in toughness were observed. Based on these results the interlaminar fracture tough ness and fracture behaviour of hybrid composites, fabricated using bead-filled epoxy matrices, have been investigated using double cantilever beam and end notch flexure specimens for Mode I and Mode II tests, respectively. The hybrid composites based on carbon bead-filled matrix shows an increase in both G(IC) initiation and G(IIC) values as compared to a glass fibre reinforced plastic laminate with unmodified epoxy matrix. The optimum bead volume fraction for the hybrid composite is between 15% and 20%. However, the unmodified epoxy glass-fibre composite shows a higher G(IC) propagation value than that of hybrid composites, due to fibre bridging, which is less pronounced in the hybrids as the presence of the beads results in a matrix-rich interply region
A parametric study of collisional and pulse attenuation on Raman threshold intensity in cluster plasmas
No full textCoulombic expansion of an atomic cluster can significantly affect the growth of stimulated Raman backscattering in cluster embedded plasmas. The pulse attenuation and the collisional absorption occur during the early phase of cluster expansion, competing against each other in determining the Raman threshold intensity in a cluster plasma. The threshold laser intensities estimated for various wave numbers of the electron plasma waves are found to be consistent with the previous result [P. K. Tiwari et al., Phys. Plasmas 14, 103101 (2007)]: Collisional threshold intensities are to be of 1 similar to 10(5) W/cm(2) at the electron-ion collisional frequency similar to 10(13) s(-1), and the pulse attenuated threshold intensities are to be of similar to 10(13) W/cm(2) for short pulse length similar to 20 fs. The pulse attenuation and collisional absorption of Raman threshold intensities are found to be inversely proportional to both the pulse duration and attenuation length. (C) 2008 American Institute of Physics.X110sciescopu
Magnetic field induction by Bohm plasma diffusion
No full textWhen Bohm diffusion is incorporated, the magnetic induction equation can be transformed into a type of heat equation which allows exact analytical solutions ( Lee and Ryu 2004 Phys. Plasmas 11 5462). This equation can admit amplification solutions for the axisymmetric magnetic field, if the diffusion velocity satisfies a certain condition. This paper discusses the case of the azimuthal field and finds that there are also analytical solutions which can amplify the magnetic field.X11sciescopu
Sustainment of Plasma Density by a Low Magnetic Field in a Dual-Frequency Capacitively Coupled Plasma
No full textDual-frequency capacitively coupled plasmas (DF-CCPs) have been used to control the ion flux by the high-frequency source and the ion bombardment energy onto the electrode by the low-frequency (LF) source separately. However, an increase in the LF voltage. which extends the maximum ion energy to a higher value, causes the reduction of the bulk plasma length with a subsequent decrease of the plasma density. By using a one-dimensional particle-in-cell/Monte Carlo simulation code, the effect of the magnetic field on a DF-CCP is investigated to find whether the plasma can be sustained during the LF voltage increase. It is found that a low magnetic field can effectively maintain the plasma density and electron temperature constant with respect to the variation of the LF voltage.1144sciescopu
A three-dimensional steady-state finite element analysis of square die extrusion by using automatic mesh generation
No full textSteady-state finite element analysis is made for three-dimensional hot extrusion of sections through square dies by using an automatic mesh generator which can generate three-dimensional meshes by shifting two-dimensional meshes. In industrial practice, the design of extrusion dies is still an art rather than science, especially for complicated profiles, because the die design for a new extrusion is developed from previous experience and in-plant trials. The objective of this study is to develop a steady-state finite element method for hot extrusion through square dies, and to provide a theoretical basis for an optimal die design and process control for the extrusion technology. In the present investigation, steady-state assumption is used for both the analyses of deformation and temperature. The analysis of temperature distribution includes heat transfer, and is carried out by decoupling from the analysis of deformation. Convection link element is adopted for the heat transfer analysis between the billet and the container, and also between the billet and the die. Computations are carried out for solid and hollow extrusion of several sections. The present method of analysis has been shown to provide good results comparable with the non-steady-state method with reduced computation time. Distributions of temperature, effective strain rate, velocity and mean stress are discussed for effective design of an extrusion die. (C) 1999 Elsevier Science Ltd. All rights reserved
Mononuclear nickel(III) and nickel(II) thiolate complexes with intramolecular S-H proton interacting with both sulfur and nickel: Relevance to the [NiFe]/[NiFeSe] hydrogenases
No full textEffects of reinjection on the scaling property of intermittency
No full textWe study the effect of the reinjection probability distribution (RPD) on the scaling property of intermittency via the renormalization group approach. When the lower bound of reinjection is below the tangent point, the critical exponent has the well known form of (z - 1)/z independent of the RPD. On the other hand, when the lower bound of reinjection is at the tangent point, the critical exponent is (z + gamma - 2)/z if the RPD is of an algebraic form with exponent gamma and is (z - 1)/z if the RPD is fixed at the tangent point. The results are confirmed by numerical simulations
Value of circulating adhesion molecules in the assessment of cardiac allograft rejection.
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