NOPR Collection:

Dielectric relaxation studies of argemone-mexicana oil in pure form and in dilute solution of benzene at different temperatures

2001-05-01T00:00:00Z

Title: Dielectric relaxation studies of argemone-mexicana oil in pure form and in dilute solution of benzene at different temperatures Authors: Bansal, A K; Singh, P J; Sharma, K S; Kumar, Satyanshu; Kumar, P R Abstract: Dielectric properties of argemone-mexicana oil have been investigated at various temperatures in pure form and in dilute solution of benzene at 100 kHz, 8.93 GHz and optical frequency of sodium light. The relaxation times and thermodynamical parameters have been determined from the measured data. These parameters are interpreted in terms of molecular and the intramolecular rotations. The present study suggests the existence of both the intra-molecular and overall orientations in the triglyceride molecule of argemone-mexicana oil under investigation. Study of enthalpy of activation (ΔH_ε ,ΔH_η) for dielectric relaxation and viscous flow suggests the existence of solid rotator phase in these molecules. Page(s): 329-334

Micro-detachment studies in paintings using sandwich hologram interferometric techniques

2001-05-01T00:00:00Z

Title: Micro-detachment studies in paintings using sandwich hologram interferometric techniques Authors: Kaura, Sushil K; Chhachhia, D P; K Aggarwal, A K Abstract: Hologram interferometric techniques are finding wide-range applications for carrying out non-destructive testing studies that are suitable in different situations. On account of the measuring accuracy of these techniques, they offer a unique application for non-destructive diagnosis of incipient faults or critical damages in precious and ancient artifacts, paintings, sculptures and monuments etc. caused due to environmental effects and aging. Investigations have been carried out by using sandwich hologram interferometric techniques for performing micro-detachment studies in paper paintings pasted and mounted on wooden panel boards. Experimental results achieved have been discussed. Page(s): 286-290

Singlet excitation energy transfer in tetracene-doped anthracene in thin film organic semiconductor

2001-05-01T00:00:00Z

Title: Singlet excitation energy transfer in tetracene-doped anthracene in thin film organic semiconductor Authors: Prasad, B; Mishra, P K Abstract: The electroluminescence (EL) spectra of pure and doped crystals appear to resemble with the spectrum in thin film form. The EL spectra of tetracene, anthracene and tetracene-doped ant anthracene in this film form have been reported. But looking at the relative intensity of undoped anthracene and tetracene bands, it appears that the band of higher intensity of anthracene (host) has been quenched by the dopant and a large part of doped system lies in the green region of the spectrum which is the characteristic emission of the dopant (guest) molecules. i.e., tetracene. The broadening of band for the doped molecule at 550 nm may be considered due to the energy transfer in this system such that the doping quenches the blue emission of host molecule (anthracene) and replaces it with the green emission of the guest molecule (tetracene).The energy band diagram and a scheme for the excitonic reaction kinetics, that agrees very well with experimental results have been constructed. It is apparent from the comparison of brightness waves that the structure of the doped films resembles very much with that of the undoped tetracene films. Page(s): 321-328

Structural study of 2, 4-dichlorobenzanilide-An aromatic substituted amide

2001-05-01T00:00:00Z

Title: Structural study of 2, 4-dichlorobenzanilide-An aromatic substituted amide Authors: Rajnikant; Gupta, Vivek K; Dinesh; Goswami, B N; Sarmah, G K; Bhattacharyya, N K; Gupta, Rachna Abstract: The crystal structure of the title compound (C₁₃H₉NOCl₂) has been determined by X-ray crystallographic techniques. The compound crystallizes in the triclinic space group Pl with unit cell parameters: a = 9.717(3), b = 10.104(3), c = 13.636(3) Å, α = 80.36(2), β = 78.20(2), γ = 70.07(2 )^o, Z = 4. The structure has been solved by direct methods and refined to R = 0.051 for 3310 observed reflections and wR(F²) = 0.149. There are two crystallographically independent molecules in the asymmetric unit. In both the molecules, the phenyl rings are planar. The crystal structure is stabilized by van der Waals forces. Page(s): 313-315