NOPR Collection:

A simple and inexpensive automated pulse programmer for pulsed NMR

2016-07-20T06:37:12Z

Title: A simple and inexpensive automated pulse programmer for pulsed NMR Authors: Reddy, V Rajagopal; Reddy, P N; Reddy, B P N Abstract: A microcomputer (IBM compatible) controlled flexible pulse programmer has been designed and built for using in pulsed nuclear magnetic resonance (NMR) spectrometer is described. It generates pulse sequences required in NMR to measure spin-lattice relaxation time T₁, spin-spin relaxation time T₂ and spin-lock relaxation time T₃. The pulse sequence parameters like pulse widths, interpulse intervals, repetition times can be programmed with menu driven software. The pulse widths can be varied from 100 ns to 6.5 ms in steps of 100 ns. The design and operational features of the pulse programmer are described in this paper. The software, developed in Turbo Basic accepts the pulse sequence parameters from the user and generates the pulse sequences as per the specified values, besides controlling the spectrometer and signal average operations. Page(s): 88-90

Characterisation of titania, zirconia and alumina powders for their surface area and pore size distribution

2016-07-20T06:37:00Z

Title: Characterisation of titania, zirconia and alumina powders for their surface area and pore size distribution Authors: Seshadri, K S; Sumangala, R K; Raj, S S; Lal, K B; Panicker, P K; Krishnasamy, V Abstract: In order to develop ceramic membranes for treating radioactive liquid effluents titania, zirconia and alumina obtained through hydrolysis of their respective alkoxides, have been characterized for their specific surface area and pore size distribution. The samples are treated over a temperature range of 673-1473 K. In all cases, the specific surface area is found to vary with temperature, with zirconia 234-2 m²/g over temperature range 743-1473K, titania 174-10 and alumina 271-141 m²/g over the temperature 673-1473K. The pore size distribution studies show the peak positions of the pore radius of titania, zirconia and alumina in the range 23-45, 19-32 and 18-48 Å, respectively, in the temperature range studied. Page(s): 85-87

Dielectric permittivity of gall-stones as a function of density

2016-07-20T06:36:44Z

Title: Dielectric permittivity of gall-stones as a function of density Authors: Singh, Jasvir; Bhatti, S S; Singh, V R Abstract: The dielectric permittivity of different types of gallstones has been determined at 150 kHz frequency at room temperature 28°C. The average values of this parameter for soft, mixed and hard type of gall-stones have been found to be 23.92, 30.31 and 40.03 respectively. This has been found to increase as the density of the specimen is increased. Page(s): 83-84

Preparation of lanthanum- β-alumina with high surface area by a homogeneous precipitation method for use as catalyst support

2016-07-20T06:29:29Z

Title: Preparation of lanthanum- β-alumina with high surface area by a homogeneous precipitation method for use as catalyst support Authors: Parida, K M; Das, J; Rao, S B Abstract: Samples containing mixtures of 5 mol % La₂O₃ and 95 mol % Al₂O₃ were prepared by homogeneous precipitation method with or without the presence of various anions, and calcined at different temperatures in the range of 873-1473 K. Sample prepared by urea hydrolysis in the absence of anions, and calcined at about 1273 K results in the formation of pure lanthanum-β-alumina (LBA) with high surface area. However, in the presence of additive anions, the formation of LBA is retarded. Page(s): 79-82