Solubility of Ruthenium Dioxide in Lead Borosilicate Glasses

The solubility of RuO₂ in a lead borosilicate glass was measured in the range of 700° to 1000°C. The effect of dissolved alumina in the glass was studied in the same range using 2%, 4%, 6%, and 10% dissolved alumina. The solubility showed an exponential dependence on temperature, and the dissolved alumina decreased the solubility at any given temperature; however, the solubility was essentially the same in all of the alumina-containing glasses. The Kelvin equation was used to deduce the concentration of RuO₂ in glass as a function of the curvature of the RuO₂ particles, and the dependence was found to be quite small. The implications of the results in processing thick-film resistors using RuO₂ as the conductive phase and these glasses as insulating phases on an alumina substrate are discussed.     

Condensation of vertical plate fins of variable cross section-limiting solutions

The purpose of the present theoretical analysis is to provide explicit solutions for the problem of condensation of vapours on the lateral surface of a long vertical plate fin of variable cross-section. The formulation yields solutions to the Limiting cases so that the results can be employed in the design of the condenser section of a flat plate heat pipe in which the fin is considered to be an essential element in transporting heat liberated by the condensing vapours. It is observed that the local and average Nusselt numbers depend on fin parameter, fin profile index, Rayleigh number and degree of subcooling.     

An Artificial-Neural-Network-Based Integrated Regional Model for Rain Retrieval Over Land and Ocean

An integrated regional model is proposed for rain-rate retrievals over land/ocean from the brightness temperature (Tb) values of the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI). The polarization-corrected temperature calculated from the 85.5-GHz channels is also considered as one of the inputs along with the nine channel Tb values. This model is applicable over the region between and . For this purpose, an artificial neural network is utilized. The collocated precipitation radar (PR) near-surface rain rates as given by a 2A25 data product is considered as a target value. The methodology consists of the separation of land and ocean pixels, the separation of stratiform and convective pixels over land/ocean, and the selection of important features (inputs) for the multilayer perceptron network by the feature selection technique for each group. For the separation of land/ocean pixels, the Tb values of the 10.65-GHz vertical channel are utilized. The values are utilized to separate the stratiform and convective pixels both over land and ocean. The rain retrieval from the developed model is validated with TRMM PR. Overall result shows the better agreement of the model-retrieved rain rate with the PR observation compared to the TMI (2A12) rain rate particularly over land. The rain retrieved from the developed model is further validated with Doppler weather radar. A reasonably good agreement is observed between these two estimations.     

Banded structure of the electrodeposited nanocrystalline Al–Mg alloy dendrites

Nanocrystalline Al–Mg dendrites with smooth (face centered cubic (fcc)-Al(Mg)) and rough (hexagonal close packed (hcp)-Mg(Al)) globular morphology were electrodeposited. The longitudinal sections of the rough globules exhibited bright–dark banded structure possessing Mg-poor and Mg-rich compositions respectively. The banded structure was explained by considering the fluctuations in potential(E)-time curve. More negative potentials result in Mg-rich dark bands. Mg-poor bright bands appear at less negative potentials. A mechanism was proposed for the banded structure formation in Al–Mg dendrites.     

Substrate effect on electrodeposited nanocrystalline Al-Mg alloy powders

Supersaturated dendritic Al-Mg alloy powders in globular form were produced using galvanostatic electrodeposition technique on polycrystalline Cu and Mg-substrates. The deposit produced on Cu-substrate possessed face centered cubic (fcc)-Al(Mg) phase with composition of ~ 18 at.% Mg. However, when Mg-substrate was used, initially hexagonal close packed (hcp)-Mg(Al) phase with ~ 77 at.% Mg was formed over which fcc-Al(Mg) phase with ~ 36 at.% Mg was nucleated. The results of the present study indicate that substrate crystal structure and estimated substrate-deposit lattice mismatch can influence the depositing phase and its composition but not the morphology of these powders.