Kerala Libraries Network (KELNET): a Proposal

Visualizes the conceptual framework and propose the development of a Kerala Library Network (KELNET) by exploring and exploiting the available and the existing social infrastructures, social softwares, open standards and technologies

Calibration approach to electron probe microanalysis: A study with PWA-1480, a nickel base superalloy

The utility of an indirect calibration approach in electron probe microanalysis is explored. The methodology developed is based on establishing a functional relationship between the uncorrected k-ratios and the corresponding concentrations obtained using one of the ZAF correction schemes, for all the desired elements in the concentration range of interest. In cases where a very large number of analyses are desired, such a technique significantly reduces the total time required for the microprobe analysis without any significant loss of precision in the data. A typical application of the method in the concentration mapping of the transverse cross-section of a dendrite in directionally solidified PWA-1480, a nickel-based superalloy, is described

A Rare Giant Pleural Thymoma in Posterior Mediastinum.

Thymoma is an epithelial neoplasm of the thymus, which commonly lies in the anterior mediastinum. Unusually, thymomas can also be found in other locations. Surgical excision, when feasible, appears to provide good results. We encountered a rare case of a thymoma that developed in the right thoracic cavity, and originating from the pleura in posterior mediastinum. We describe the clinical scenario, investigations, and our management of the patient

Secondary arm coarsening and microsegregation in superalloy PWA-1480 single crystals: Effect of low gravity

Single crystal specimens of nickel base superalloy PWA-1480 were directionally solidified on ground and during low gravity (20 sec) and high gravity (90 sec) parabolic maneuver of KC-135 aircraft. Thermal profiles were measured during solidification by two in-situ thermocouples positioned along the sample length. The samples were quenched during either high or low gravity cycles so as to freeze the structures of the mushy zone developing under different gravity levels. Microsegregation was measured by examining the solutal profiles on several transverse cross-sections across primary dendrites along their length in the quenched mushy zone. Effect of gravity level on secondary arm coarsening kinetics and microsegregation have been investigated. The results indicate that there is no appreciable difference in the microsegregation and coarsening kinetics behavior in the specimens grown under high or low gravity. This suggests that short duration changes in gravity/levels (0.02 to 1.7 g) do not influence convection in the interdendritic region. Examination of the role of natural convection, in the melt near the primary dendrite tips, on secondary arm spacings requires low gravity periods longer than presently available on KC-135. Secondary arm coarsening kinetics show a reasonable fit with the predictions from a simple analytical model proposed by Kirkwood for a binary alloy

Production status of GaAs/Ge solar cells and panels

GaAs/Ge solar cells with lot average efficiencies in excess of 18 percent were produced by MOCVD growth techniques. A description of the cell, its performance and the production facility are discussed. Production GaAs/Ge cells of this type were recently assembled into circuits and bonded to aluminum honeycomb panels to be used as the solar array for the British UOSAT-F program

Efficacy of a fungal fermented product as fishmeal replacement in the diet of Penaeus monodon Fabricius post-larvae

The efficacy of diets, formulated by inclusion of an Aspergillus niger fermented product (AFP) as fish meal substitute, for Penaeus monodon post-larvae was determined. AFP was derived by solid state fermentation (SSF) of a mixture of soybean flour, wheat flour, groundnut oil cake and sesame oil cake in the ratio of 4: 3: 2: 1 respectively for 96 h. The feeding trial was conducted in post-larvae stocked @10 animals in circular perspex tanks containing 40 l of water with five dietary treatments each with three replicates for 52 days. The diets containing graded levels of AFP substituting 0, 50, 150, 250 and 350 g kg-1 of fishmeal were fed to the post-larvae. Data on the growth performance and nutrient utilization efficiency were recorded from the feeding trials. Results showed that the post-larval shrimp fed diet containing 150 g kg-1 AFP exhibited significantly better (p<0.05) growth rate (14.79 mg d-1 post-larva-1), feed conversion ratio (1.62), protein efficiency ratio (1.64) and apparent protein utilization (25.39) than the other diets. The diet with 350 g kg-1 AFP showed the best apparent protein digestibility (87.74 %), apparent fat digestibility (97.95 %) and apparent dry matter digestibility coefficient (77.09 %) among the test diets. The results of the present study suggest that AFP can be used to improve the digestibility of nutrients and that partial replacement of fishmeal is possible in P. monodon post-larval diets under optimum rearing conditions

Electric field control of magnetism in Si3N4 gated Pt/Co/Pt heterostructures

In this work we show the presence of a magnetoelectric coupling in silicon-nitride gated Pt/Co/Pt heterostructures using X-ray photoemission electron microscopy (XPEEM). We observe a change in magnetic anisotropy in the form of domain wall nucleation and a change in the rate of domain wall fluctuation as a function of the applied electric field to the sample. We also observe the coexistence of in-plane and out of plane magnetization in Pt/Co/Pt heterostructures in a region around the spin reorientation transition whose formation is attributed to substrate surface roughness comparable to the film thickness; with such domain configuration, we find that the in-plane magnetization is more sensitive to the applied electric field than out of plane magnetization. Although we find an effective magnetoelectric coupling in our system, the presence of charge defects in the silicon nitride membranes hampers a systematic electrostatic control of the magnetization.Comment: 23 pages, 5 figure