Modeling PD inception voltage of epoxy resin post insulators usingan adaptive neural network

One of the parameters used to characterize the partial discharge (PD) behavior is its inception voltage. The partial discharge inception voltage (PDIV) should always be higher than the operating voltage to ensure that PD does not occur at or near operating voltage. Under these circumstances, other PD parameters such as apparent charge, energy dissipation need not be considered. This paper deals with modeling of PDIV of epoxy-resin post insulators using a neural network (NN). The PDIV is obtained experimentally for various shapes and sizes of post insulators, with a working voltage in the range of 3.3 to 33 kV. The electrode spacing d and creepage length l are the key parameters employed for the present modeling. An adaptively trained multilayer NN is employed for the modeling. Detailed studies are carried out to optimize the NN parameters for minimum error. The model results obtained closely follow the experimental data indicating the effectiveness of NN as an efficient tool in estimation of PDIV of epoxy-resin postinsulators     

MRI of the brain in patients with miliary pulmonary tuberculosis without symptoms or signs of central nervous system involvement

MRI was performed on patients with miliary pulmonary tuberculosis to look for brain involvement and to study the features sequentially, during treatment. We studied seven patients with typical radiographic tuberculosis, and no symptoms or signs of central nervous system involvement. Conventional spin-echo (SE) imaging, including contrast enhanced images, was performed in all cases. All patients showed brain involvement: four patients showed lesions mainly less than 3 mm in diameter, better seen on contrast-enhanced images. These patients showed oedema around the lesions after 2 months of treatment, with subsequent regression on follow-up. The remaining three patients had multiple lesions, 3 mm or more in diameter, which showed a gradual decrease on follow-up. We conclude that the brain may commonly be involved in miliary pulmonary tuberculosis. The response to treatment depends on the stage of the granuloma and shows a definite pattern of healing on follow-up.     

Microstructure and High Temperature Impression Creep Properties of Mg–3Ca–xZr (x = 0.3, 0.6, 0.9 wt%) Alloys

The current study has investigated the influence of zirconium (Zr) addition to Mg–3Ca–xZr (x = 0.3, 0.6, 0.9 wt%) alloys prepared using argon arc melting on the microstructure and impression properties at 448–498 K under constant stress of 380 MPa. Microstructural analysis of as-cast Mg–3Ca–xZr alloys showed grain refinement with Zr addition. The observed grain refinement was attributed to the growth restriction effect of Zr in hypoperitectic Mg–3Ca–0.3 wt% Zr alloys. Heterogeneous nucleation of α-Mg in properitectic Zr during solidification resulted in grain refinement of hyperperitectic Mg–3Ca–0.6 wt% Zr and Mg–3Ca–0.9 wt% Zr alloys. The hardness of Mg–3Ca–xZr alloys increased as the amount of Zr increased due to grain refinement and solid solution strengthening of α-Mg by Zr. Creep resistance of Mg–3Ca–xZr alloys increased with the addition of Zr due to solid solution strengthening of α-Mg by Zr. The calculated activation energy (Q_a) for Mg–3Ca samples (131.49 kJ/mol) was the highest among all alloy compositions. The Q_a values for 0.3, 0.6 and 0.9 wt% Zr containing Mg–3Ca alloys were 107.22, 118.18 and 115.24 kJ/mol, respectively.     

迎向更环保的明天：半导体让汽车更环保

低价位新车打入印度汽车市场,印度的汽车总数将于2012年超过4000万辆。空气质量已成为印度政府关注的首要课题,而针对省油引擎管理系统的重要性,     

Transmission parameters of a class of coupled distributed networks

It is shown how the equations of a class of coupled distributed networks can be decoupled, and their transmission parameters expressed in terms of those of an equivalent scalar system.     

Mechanism of the thesaurismosis and altered lysosomal dynamics induced by poly-D-glutamic acid in kidney proximal tubular cells

In the companion paper, we report that a single injection of poly-D-glutamic acid causes an acute lysosomal storage condition and apparently impairs the lysosomal fission dynamics. The present paper addresses the mechanisms of these two alterations using a combination of in vivo and in vitro biochemical approaches. After a single intravenous injection, 14C-poly-D-glutamic acid was rapidly cleared from the plasma and appeared in the urine. Yet, a small but sizable fraction of the injected polymer was taken up by the kidney cortex through a saturable process (Kuptake, 150 mg/kg body wt; uptakemax 96 micrograms/g cortex). Analytical subcellular fractionation of cortex homogenates demonstrated that at initial stages, the 14C label was predominantly associated with subcellular particles of intermediate size and low equilibrium density, and was therefore slowly transferred to larger particles equilibrating at high density, then codistributing with the lysosomal hydrolases. At a concentration of 10 mg/ml (equivalent to its estimated concentration in lysosomes), poly-D-glutamic acid formed micronic aggregates ( > or = 10 microns) when brought to solution at pH < or = 6 in relation to its decreased ionization (pKa of lateral chains approximately equal to 4.25). Finally, 1 day after the injection of poly-D-glutamic acid, the activities of several lysosomal enzymes (hexosaminidase, cathepsin B, acid sphingomyelinase, and sulfatase B), but not of all of them (eg, acid phosphatase), were increased in the kidney cortex. We propose that poly-D-glutamic acid reaches lysosomes by adsorptive endocytosis and becomes concentrated within these organelles because its withstands hydrolysis until it forms aggregates or precipitates, causing a decrease in the fluidity or the deformability ("gelling") of the lysosomal matrix. This should alter the dynamics of intercommunication of these organelles by impairing their fission without a proportionate effect on their fusion properties. In addition, the data suggest that the presence of poly-D-glutamic acid directly or indirectly slows down the degradation of several lysosomal enzymes.     

Machine learning approach for automatic diagnosis of Chlorosis in Vigna mungo leaves

Multimedia Tools and Applications - Viral infection in crops is something that may lead to a huge loss in crop yield as there are no known recovery procedures. Also, at the onset of yellowing in a...     

On the steady flow produced in fluid-particle suspension by an infinite rotating disk with surface suction

The steady flow of a fluid-particle suspension over an infinite rotating disk with uniform suction is considered. The equations of motion are reduced to ordinary differential equations by similarity transformations and solved numerically by using a least-squares finite-element method. Some typical results for both fluid and particle phases and density distributions of the particles are presented graphically for the suction parameter A = 3.0 in order to illustrate some interesting features of the solutions. It is observed that the radial velocity of the particle attains its maximum on the surface of the disk and the particles slip in the tangential direction on the disk. The magnitudes of the radial velocity components of both the fluid and particle phases are found to decrease rapidly as suction increases.     

Spectral distribution of photocurrent in poly(6-tert-butyl-3-methyl-3,4-dihydro-2H-1,3-benzoxazine)

The spectral distribution of photoconductivity in poly(6-tert-butyl-3-methyl-3,4-dihydro-2H-1,3-benzoxazine) was studied in the sandwich configuration with indium tin oxide and silver electrodes. The photocurrent was found to originate mainly from the bulk dissociation of excitons with lesser contribution from electrode-mediated exciton dissociation. The molecule was fluorescent, but in the presence of the electron acceptor molecule 2,4,6-trinitrophenol (TNP), the intensity was reduced. The reduction in fluorescence intensity corresponded to an increase in photocurrent. The molecule showed photoconductivity in the visible without any sensitizers, which makes it suitable for stable photorefractive composites.