NOPR Collection:

Study of electrical properties of glass thermoelectret

Tue, 01 Apr 2003 00:00:00 GMT

Title: Study of electrical properties of glass thermoelectret Authors: Upadhyay, M M; Ubale, S K; Adgaonkar, C S Abstract: Thermoelectrets were prepared by applying different polarizing fields at different polarizing temperatures to the glass of composition [50ZnO-50B₂O₃]. The dc conductivity, dielectric constant and ac conductivity of these glass electrets were measured and the properties were found to be influenced by the polarizing field as well as temperature Page(s): 169-172

Effect of annealing on spray deposited Ni-Zn ferrite thin films

Tue, 01 Apr 2003 00:00:00 GMT

Title: Effect of annealing on spray deposited Ni-Zn ferrite thin films Authors: Mathe, V L; Bhosale, C H Abstract: The thin films of Ni-Zn ferrite have been synthesized using spray pyrolysis technique onto the glass substrate. The as deposited films are found to be amorphous and the films become crystalline after annealing them in the temperature range 400-600^oC in the steps of 100^oC for 6 h. It is found that the crystallinity increases with annealing temperature. Further for the film annealed at 600^oC, some additional XRD peaks of the glass substrate have been observed. Therefore, the films annealed at 500^oC are characterized further by EDAX technique. The elemental analysis by EDAX confirms the stoichiometric formation of Ni-Zn ferrite. The resistivity for all the samples with respect to temperature shows rapid decrease in resistivity at around 180^oC. This may be due to oxido-reduction process that appears during heating of ferrite sample in the air. 3Fe²⁺ ↔2Fe³⁺ total reaction takes place in the temperature range 100-250^oC. However, there is no much difference in the resistivity value at room temperature for these samples. Page(s): 166-168

Viscous behaviour of asphaltic mixtures: Simplified fatigue test method

Tue, 01 Apr 2003 00:00:00 GMT

Title: Viscous behaviour of asphaltic mixtures: Simplified fatigue test method Authors: Akbulut, H Abstract: A continuously increasing demand on roads and the need to reduce the construction costs has led to the industry requiring simplified test methods which measure the mechanical properties of bituminous materials. The method traditionally used in the industry is based on Marshal mix design, which basically determines the stability and flow test values and do not measure any fundamental property of the mix thereby pavement performance. In contrast, there are a number of key properties that can be measured to determine the mechanical properties of a bituminous mix, which are vitally important in determination of long-term performance of the mixtures. This paper describes a method, the AKAL test method, which simplifies the ITFT test and measures viscous behaviour to predict the development of permanent strain accumulation, therefore, fatigue- life and long- term performance of asphalt mixtures. Page(s): 161-165

Substituted thiobiurets and their molybdenum and tungsten complexes as corrosion inhibitors for mild steel in 1.0 N sulphuric acid

Tue, 01 Apr 2003 00:00:00 GMT

Title: Substituted thiobiurets and their molybdenum and tungsten complexes as corrosion inhibitors for mild steel in 1.0 N sulphuric acid Authors: Rastogi, R B; Singh, M M; Yadav, M; Singh, K Abstract: Corrosion inhibition studies of mild steel in 1.0 N sulphuric acid have been performed at 25°C using substituted thiobiurets and their molybdenum and tungsten complexes as inhibitors. All the inhibitors have been found to inhibit the corrosion process by getting adsorbed on the metal surface. Among the studied thiobiurets, methoxyphenyl derivative behaved as the best corrosion inhibitor. The inhibitive properties of thiobiurets improved considerably on complexation with molybdenum and/or tungsten ions. Page(s): 155-160