http://nopr.niscair.res.in/handle/123456789/78 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/174 Title: Dielectric relaxation studies of binary mixtures of N-methylformamide and benzonitrile in benzene solution using microwave absorption data <br/> <br/>Authors: Kumar, Rajesh; Thakur, Nagesh; Sharma, D R; Rangra, V S; Negi, N S <br/> <br/>Abstract: Using standard standing wave microwave techniques and following the single frequency (9.885 GHz) concentration variational method, the dielectric relaxation time (τ) and dipole moment (μ) of binary mixtures of different molar concentrations of N-methylformamide (NMF) in the binary mixtures of N-methylformamide (NMF) and benzonitrile (C₆H₅CN) in benzene solutions have been calculated at different temperatures (25, 30, 35 and 40ºC). The energy parameters (ΔHε, ΔFε, ΔSε) for the dielectric relaxation process of binary mixtures containing 50 mol% of NMF have been calculated at different temperatures and comparison has been made with the corresponding energy parameters (ΔHη, ΔFη, ΔSη) for the viscous flow process. Based on these studies, it is inferred that dielectric relaxation process can be treated as a rate process just like the viscous flow process. Solute-solvent molecular associations have been proposed. <br/> <br/>Page(s): 167-172 http://nopr.niscair.res.in/handle/123456789/173 Title: Strain induced non-linear conduction in epitaxial La₀.₇A₀.₃MnO₃ manganite thin films <br/> <br/>Authors: Vachhani, P S; Solanki, P S; Markna, J H; Parmar, R N; Bhalodia, J A; Kuberkar, D G <br/> <br/>Abstract: In this paper, the current-voltage (I-V) properties of La₀.₇A₀.₃MnO₃ (A = Ca, Sr, Ba) manganite thin films grown on single crystalline LAO (100) substrate using chemical solution deposition (CSD) technique have been reported. Epitaxial nature of all the films has been confirmed from XRD measurements. The I-V measurements carried out on La₀.₇Ba₀.₃MnO₃ (LBMO) films show an unusual non-linear transport behaviour contrary to that observed for La₀.₇Ca₀.₃MnO₃ (LCMO) and La₀.₇Sr₀.₃MnO₃ (LSMO) films. This non-linearity has been explained in terms of non-uniform strain distribution resulting due to mismatch in the lattice parameters of LBMO film and substrate. The conductance data for all the films have been fitted using Simmon’s model and the possible mechanism of charge conduction in the films has been discussed. <br/> <br/>Page(s): 163-166 http://nopr.niscair.res.in/handle/123456789/172 Title: Effect of cement and EPS beads ratios on compressive strength and density of lightweight concrete <br/> <br/>Authors: Kan, Abdulkadir; Demirboğa, Ramazan <br/> <br/>Abstract: The compressive strengths and slump values of concretes made up of mixtures of expanded polystyrene (EPS) beads and cement were investigated. To determine the effect of Portland cement (PC)/EPS ratio, on the compressive strength of EPS concrete, 1/0 (control sample), 1:4, 1:2, 3:4 and 1:1 mix proportion by volume were used. EPS beads content for the mixtures were kept constant at 0.05 m3. The analysis of the test results leads to the conclusion that with the increase of cement to EPS beads ratio in the mixes, both density and compressive strength of concretes increased up to 4 and 350 times respectively, when compared to the control sample. Hardened concrete densities and compressive strength varied from 464 to 1940 kg/m³, and 0.11 to 38.50 MPa, respectively. Slump values of the mixes were changed from 8 to 43 mm. <br/> <br/>Page(s): 158-162 http://nopr.niscair.res.in/handle/123456789/171 Title: Investigation of the low temperature performances of polymer and fiber modified asphalt mixtures <br/> <br/>Authors: Tasdemir, Yuksel; Agar, Emine <br/> <br/>Abstract: In this study, effects of polymer and fiber modification on low temperature properties of bituminous mixtures were studied. One aggregate, one asphalt binder type, three additives (polymer, synthetic fiber and loose cellulose fiber) and three 85ºC oven aging levels (0, 5 and 25 days) were considered. The thermal stress restrained specimen test (TSRST) was used to evaluate the low temperature cracking resistance and aging performance of modified asphalt concrete specimens. The analysis of covariance was performed using a general linear model (GLM) procedure on the TSRST results by using statistical analysis system (SAS) software. Aging levels and type of additive were determined as most important factors that affect fracture temperature and fracture strength. Fracture temperature becomes warmer with the increase in the degree of aging. It was observed that fracture temperature and fracture strength change according to additive type used. <br/> <br/>Page(s): 151-157