Microirrigation Lateral Design using Lateral Discharge Equation

A simple and accurate method is developed for designing single, paired, and tapered microirrigation laterals. The hydraulics of the lateral is evaluated using a lateral discharge equation approach. A simple power equation is used to express the relationship between the inlet flow rate and inlet pressure head of the lateral. Keeping the flow variation within the specified limit, a procedure for designing the length of the tapered section is developed. The lateral is designed using a step-by-step method. The length of the tapered section is determined by the golden section search method.     

Molybdenum-phosphorus compounds based passivator to control corrosion of hot dip galvanized coated rebars exposed in simulated concrete pore solution

Hot dip galvanized (HDG) coating passivated with molybdenum-phosphorus compounds based passivator exhibits high degree of corrosion protection exposed in chloride contaminated simulated concrete pore solution (SPS). The coating develops very stable corrosion products and its corrosion potential gets greatly ennobled due to the formation of a complex passive layer. This composite layer has been identified as hydrozincite (HZ) embedded with several other compounds. The studies reveal that the presence of passive films on HDG makes the HZ layer more impervious and less soluble in the test electrolyte. The layer also helps in faster development of hydrozincite film on HDG surface. A faster healing of defects in hydrozincite layer takes place for passivated than the unpassivated surface. Electrochemical impedance spectroscopy (EIS), Raman Spectroscopy, Scanning Electron Microscopy (SEM), energy dispersive X-ray analysis (EDXA), and X-ray diffraction (XRD) studies etc. have been performed to study the kinetics and understand the mechanism of formation of hydrozincite at the corroding interface. These studies are expected to provide a new area in development of lesser polluting protective passive layer on galvanized coatings.     

Study of polycrystalline sintered compacts of diamond

Study of polycrystalline sintered compacts of diamond has been made using powder X-ray diffraction, scanning electron microscopy (SEM) and energy- dispersive X-ray analysis (EDX). Various crystalline phases formed at high temperature and high pressure, microstructure, particle-size distribution of diamond and binder and concentration of different elements in the sintered diamond compacts were determined.     

An Evaluation of Methods for Neuromagnetic Image Reconstruction

In this paper, we discuss several aspects of a potential new medical imaging modality for producing a quantitative three-dimensional map of neuron current densities associated with brain function. The neuromagnetic image is produced by reconstructing a current dipole field from external magnetic field measurements made with an array of superconducting quantum interference device (SQUID) detectors. This field is produced by numerical inversion of the Biot-Savart equation. The purpose of the work is to investigate fundamental limits on the feasibility of the proposed system under ideal conditions. The following problems are addressed: 1) What are the factors limiting resolution of the system? 2) What is a suitable model for neural activity in the brain? 3) What classes of algorithms are suitable for estimating the model parameters? The major conclusion of this work is that the inversion problem is severely ill-posed and the choice of model and estimation algorithm are crucial in obtaining reasonable solutions. A class of solutions, termed minimum dipole, is proposed as a means of obtaining more acceptable results.