An investigation on molecular dynamics of binary mixtures of N-methylacetamide and tetramethylurea in microwave region

The dielectric relaxation times (τ)and the dipole moments (µ) of the binary mixtures of different molar concentrations of tetramethylurea (TMU) in the binary mixtures of N-methylacetamide (NMA) and tetramethylurea (TMU) in benzene solutions have been calculated by using standard standing wave microwave techniques and Gopala Krishna’s single frequency (9.90 GHz) concentration variational method at different temperatures (25 °C, 30 °C, 35 °C and 40 °C). The energy parameters (He, Fe, Se) for the dielectric relaxation process of binary mixtures containing 30% mole-fraction of TMU have been calculated at the respective given temperatures and the comparison has been made with the corresponding energy parameters (Hη, Fη, Sη) for the viscous flow. On the basis of the observations, it is found that the dielectric relaxation process can be treated as the rate process like the viscous flow process. The solute-solute and solute-solvent types of the molecular associations have been predicted

Resistivity dependent dielectric and magnetic properties of Pb(Fe0.012Ti0.988)O3 nanoparticles

High resistivity in nanostructured Pb(Fe0.012Ti0.988)O3 system prepared by using polyvinyl alcohol (PVA) in chemical route is observed. The PVA acts as a surfactant to limit the particle size. The Fe substitution for Ti controls the chemical stoichiometry and reduces the lattice distortion, i.e., c/a ratio, and hence the transition temperature reduces with Fe content. The phase structure, morphology, particle size, dc resistivity, and dielectric and magnetic properties of Pb(Fe0.012Ti0.988)O3 nanoparticles have been characterized by x-ray diffraction, transmission/scanning electron microscopy, source meter, LCR meter, and vibrating sample magnetometer. The results indicate that the nanosize particles have high resistivity, which improves the dielectric constant at high-frequency region and increases magnetization of the specimens. The observed variable-range-hopping conduction mechanism indicates that Fe doping leads to the occurrence of local defect states in the PbTiO3 lattice. The dispersionless dielectric properties with low loss are observed up to 15 MHz. The dielectric properties are improved than those obtained by the conventional process. The initial permeability values do not exhibit much variation up to ferromagnetic transition temperature after which it falls sharply. The large value of saturation magnetization is observed at room temperature

Effect of Sn Addition on Thermal and Optical Properties of Pb9Se71Ge20-xSnx (8≤x≤12) Glass

Study of thermal and optical parameters of Pb9Se71Ge20-xSnx  (8≤x≤12) glass has been undertaken. Crystallization and glass transition kinetics has been investigated under nonisothermal conditions by DSC technique. Phase separation has been observed in the material and is investigated by taking the XRD of annealed bulk samples. The material possesses good glass forming ability, high value of glass transition temperature about 420 K, and glass stability. Optical band gap and other optical constants such as refractive index and extinction coefficient have been determined. The isoelectronic substitution of Ge with Sn in the glassy system reduces the optical band gap and enhances the thermal properties

Dielectric relaxation studies of binary mixtures of tetrahydrofuran and N-methylacetamide in benzene solutions using microwave absorption data

415-419Using standard standing wave microwave X-band technique and by following Gopala Krishna’s single frequency (9.90 GHz) concentration variational method, the dielectric relaxation times ( ) and the dipole moments ( ) of dilute solution of tetrahydrofuran(THF), N-methylacetamide(NMA) and THF+NMA binary mixtures in benzene solutions have been calculated at different temperatures 25°, 30°, 35° and 40°C. The energy parameters (He, Fe, Se) for the dielectric relaxation process for THF+NMA binary mixture containing 30 mol% THF have been calculated at 25°, 30°, 35° and 40°C and compared with the corresponding viscosity parameters. A good agreement between the free energy of activation from these two sets of values shows that the dielectric relaxation process like the viscous flow process can be treated as the rate process. From relaxation time behaviour of THF and NMA binary mixture in benzene solution, solute-solute types of the molecular association have been proposed

Dielectric relaxation studies of binary mixtures of tetrahydrofuran and N,N-dimethylacetamide in benzene solutions using microwave absorption data

42-46The dielectric relaxation times (t) and dipole moments (m) of the binary mixtures of different molar concentrations of tetrahydrofuran (THF) in the binary mixtures of tetrahydrofuran (THF) and N,N-dimethylacetamide (DMA) in benzene solutions have been studied. The physical parameters t and µ have been calculated by using standard standing wave microwave techniques and Gopala Krishna’s single frequency (9.90GHz) concentration variational method at different temperatures (25°, 30°, 35° and 40°C). The energy parameters (Hs, Fs, Ss) for the dielectric relaxation process for THF+DMA binary mixture containing 50 mol% THF have been calculated at 25°, 30°, 35° and 40°C and compared with the corresponding viscosity parameters. From the observations, it is found that the dielectric relaxation process like the viscous flow process can be treated as the rate process. On the basis of above studies, solute-solvent type of the molecular association has been proposed

An investigation on molecular dynamics of binary mixtures of N-methylacetamide and tetramethylurea in microwave region

896-901The dielectric relaxation times (τ)and the dipole moments (µ) of the binary mixtures of different molar concentrations of tetramethylurea (TMU) in the binary mixtures of N-methylacetamide (NMA) and tetramethylurea (TMU) in benzene solutions have been calculated by using standard standing wave microwave techniques and Gopala Krishna’s single frequency (9.90 GHz) concentration variational method at different temperatures (25 °C, 30 °C, 35 °C and 40 °C). The energy parameters (He, Fe, Se) for the dielectric relaxation process of binary mixtures containing 30% mole-fraction of TMU have been calculated at the respective given temperatures and the comparison has been made with the corresponding energy parameters (Hη, Fη, Sη) for the viscous flow. On the basis of the observations, it is found that the dielectric relaxation process can be treated as the rate process like the viscous flow process. The solute-solute and solute-solvent types of the molecular associations have been predicted

Reporting of Indian chemical literature in Referatiynyi Zhurnal – Khimiya

81-86<span style="font-size:10.0pt;line-height: 115%;font-family:" calibri","sans-serif";mso-fareast-font-family:"times="" new="" roman";="" mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;mso-fareast-language:="" en-us;mso-bidi-language:ar-sa"="" lang="EN-US">Study is based on periodical literature on chemistry and chemical technology excluding metallurgy as announced in Indian Science Abstracts Vol. 1, 1965. The coverage of articles worked out subject-wise comes to 31%. In all 73 periodicals reported Indian chemical literature, out of which 39 were Indian and amongst the Indian titles only 13 were devoted to chemistry and chemical technology. During 1964 there were 42 periodicals published in India on the subject, the coverage of periodicals thus comes to about 31%. A total number of 282 principal authors figured in the RZ - Khimiya, out of which 46 had contributed more than one paper.</span

Dielectric relaxation studies of binary mixtures of N-methylformamide and benzonitrile in benzene solution using microwave absorption data

167-172Using 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

Dielectric relaxation studies of binary mixture of pyridine and N,N-dimethylformamide in benzene solution using microwaves absorption data

264-268The dielectric relaxation time (t) of binary mixtures of different molar concentrations of pyridine (C5H5N) and N,N-dimethylformamide (DMF) in benzene solution has been calculated by using standard microwave techniques and Gopala Krishna’s single frequency (9.875 GHz) concentration variational method at different temperatures (25, 30, 35 and 40°C). The solute-solute molecular associations have been proposed. The dielectric relaxation has been found to be an activated process. The energy parameters for this activated process have been calculated and compared with that of viscous flow process

Dielectric relaxation studies of binary mixtures of N-methylacetamide and N, N-dimethylacetamide in benzene solutions using microwave absorption data

759-763Single frequency concentration variational method of Gopala Krishna, Trans Faraday Soc, 33 (1957) 767., has been used to determine the dielectric relaxation times() and the dipole moments(μ) of dilute solution of N-methylacetamide(NMA), N,N-dimethylacetamide(DMA) and NMA+DMA binary mixtures in benzene solutions at 25, 30, 35C and 40ºC by the standard standing wave techniques at 9.90GHz. Energy parameters (ΔH, ΔF, ΔS) for the dielectric relaxation process of NMA+DMA binary mixtures containing 30% of DMA have been calculated at 25, 30, 35 and 40ºC. Comparison has been made with the corresponding energy parameters for viscous flow. From the observations, it is found that the dielectric relaxation process like the viscous flow process can be treated as the rate process. On the basis of above studies, solute-solute and solute-solvent types of the molecular associations have been predicted