NOPR Collection:

Microwave absorption and relaxation processes of ternary mixtures of non-rigid polar liquids

Thu, 01 Nov 2001 00:00:00 GMT

Title: Microwave absorption and relaxation processes of ternary mixtures of non-rigid polar liquids Authors: Rewar, G D; Bhatnagar, D Abstract: The dielectric absorption of three acrylates and their mixture compositions as liquid dielectric samples have been studied at MW frequency 9.132 GHz in dilute solution of carbon tetrachloride in the temperature range 300-330 K. Different dielectric parameters like dielectric constant ɛ′ and dielectric loss ɛ′′ at microwave frequency, dielectric constant ɛ_δ at static frequency and dielectric constant ɛ_∞ at optical frequency have been determined. Using these dielectric data, distribution parameter α, various relaxation times, viz. ₀, ₁, and ₂ of individual components and their ternary mixture compositions have been calculated. Thermo dynamical parameters like molar energy of activation ΔF_ɛ molar enthalpy of activation ΔH_ɛ and molar entropy of activation ΔS_ɛ have been evaluated by considering the relaxation as the rate process. Variation of In (₂T) versus 1/T indicates exponential decay of relaxation time with temperature for dielectric relaxation process. The relaxation time values for single component solutions agree well with literature values while relaxation times of ternary mixture compositions are consistent with the computed values obtained from various theoretical relations. Page(s): 707-713

Optical study of some nematic mixtures

Thu, 01 Nov 2001 00:00:00 GMT

Title: Optical study of some nematic mixtures Authors: Anand, P P; Singh, Rajbir; Agarwal, V K; Bahadur, B Abstract: Optical birefrigence study of four multi-component nematic mixtures E-80, E-90, E-100 and E-110 (all from E. Merck), were carried out, providing information about their transition temperatures and microscopic order parameter (S). Page(s): 752-754

Microwave and laser Raman spectroscopy of o-chlorotoluene

Thu, 01 Nov 2001 00:00:00 GMT

Title: Microwave and laser Raman spectroscopy of o-chlorotoluene Authors: Nair, K P R; Eappen, Shibu M Abstract: The microwave spectrum of o-chlorotoluene C₆H₄CH₃Cl shows distinct rotational structures due to four excited vibrational states over and above the ground state spectrum. The vibrational frequency calculated from the relative intensities of the ground and first excited states in the microwave spectra is identified in the laser Raman spectra and is believed to be the first torsional state of the molecule. Page(s): 750-751

Radon monitoring in underground water of Gurdaspur and Bathinda districts of Punjab, India

Thu, 01 Nov 2001 00:00:00 GMT

Title: Radon monitoring in underground water of Gurdaspur and Bathinda districts of Punjab, India Authors: Virk, H S; Walia, V; Bajwa, B S Abstract: Radon monitoring has become a global phenomenon due to its health hazard. More than 55 % radiation dose delivered to the human kind on the globe from all natural sources is due to radon alone. Radon measurements have been carried out in groundwater in Gurdaspur and Bathinda districts of Punjab, India. Radon concentration values in potable water show a wide variation depending on its source and location. Generally, radon concentration values in hand-pump drawn groundwater have been found to be higher than the values determined for water supplied from other sources. Mineral water has the minimum radon concentration compared with groundwater sources. No correlation is found between radon concentration and uranium content of groundwater in Bathinda district. Page(s): 746-749