Microwave Research Laboratory

Aurangābād, India

Microwave Research Laboratory

Aurangābād, India
SEARCH FILTERS
Time filter
Source Type

Jadhavpatil V.L.,Microwave Research Laboratory | Undre P.B.,Dr. Babasaheb Ambedkar Marathwada University | Helambe S.N.,Microwave Research Laboratory
International Journal of Pharma and Bio Sciences | Year: 2013

Dielectric relaxation measurements on Methanol - Dimethylaminoethanol solvent mixtures have been carried out across the entire concentration range using Time Domain Reflectometry technique at 15, 25, 35 and 45°C over the frequency range from 10 MHz to 20 GHz. The mixtures exhibit a principle dispersion of the Davidson-Cole relaxation type at microwave frequencies. The Bilinear calibration method is used to obtain complex permittivity ε*(ω) from complex reflection coefficient ρ*(ω) over the frequency range 10 MHz to 10 GHz. The excess permittivity (εE), excess inverse relaxation time (1/τ)E, Kirkwood correlation factor (geff) and thermodynamic parameters are also calculated to study the Solute-Solvent interaction.


Undre P.B.,Dr. Babasaheb Ambedkar Marathwada University | Khirade P.W.,Dr. Babasaheb Ambedkar Marathwada University | Jagdale S.B.,Microwave Research Laboratory | Helambe S.N.,Microwave Research Laboratory | Mehrotra S.C.,Dr. Babasaheb Ambedkar Marathwada University
Lithuanian Journal of Physics | Year: 2011

Dielectric relaxation measurements on formamide (FA) - ethanolamine (ETA) solvent mixtures have been carried out across the entire concentration range using time domain reflectometry technique at 15, 25, 35, and 45 °C over the frequency range from 10 MHz to 10 GHz. The mixtures exhibit a principle dispersion of the Davidson-Cole relaxation type at microwave frequencies. Bilinear calibration method is used to obtain complex permittivity E*(w) from complex reflection coefficient p*(w) over the frequency range 10 MHz to 10 GHz. The excess permittivity EE, excess inverse relaxation time (1/T)E, Kirkwood correlation factor geff, and thermodynamic parameters such as Gibbs energy of activation ΔG and molar enthalpy of activation ΔH are also calculated to study the solute-solvent interaction. © Lithuanian Academy of Sciences, 2011.


Dharne G.M.,Microwave Research Laboratory | Maharolkar A.P.,Microwave Research Laboratory | Patil S.S.,Dr. Babasaheb Ambedkar Marathwada University | Khirade P.W.,Dr. Babasaheb Ambedkar Marathwada University
International Journal of Pharma and Bio Sciences | Year: 2010

Dielectric relaxation measurements of Allyl Chloride (AC) with Ethanol mixture for different concentrations over the frequency range 10MH Z to 20GH Z at 308K and 318K have been carried out using Picoseconds Time Domain Reflectometry (TDR). Static permittivity (ε 0), dielectric constant at high frequency (ε ∞) and relaxation time (τ) were found through dielectric measurements. The Bruggeman factor (f B), Kirkwood correlation factor (ge ff), excess static permittivity (ε 0 E), and excess Inverse relaxation time (1/τ) E were determined and discussed to yield information on the intermolecular interactions and the Dynamics of the mixture of the system.


Undre P.B.,Dr. Babasaheb Ambedkar Marathwada University | Khirade P.W.,Dr. Babasaheb Ambedkar Marathwada University | Rajenimbalkar V.S.,Microwave Research Laboratory | Helambe S.N.,Microwave Research Laboratory | Mehrotra S.C.,Dr. Babasaheb Ambedkar Marathwada University
Journal of the Korean Chemical Society | Year: 2012

Using time domain reflectometry, the complex dielectric spectra between 10 MHz to 20 GHz has been measured in the whole composition range at 10, 20, 30 and 40 °C for the binary mixtures of ethylene glycol and dimethyl sulfoxide. For all the mixtures, only one dielectric loss peak was observed in this frequency range. The relaxation in these mixtures can be described by a single relaxation time using the Debye model. A systematic variation is observed in dielectric constant (ε 0) and relaxation time (τ). The excess permittivity (ε E), excess inverse relaxation time (1/τ) E, Kirkwood correlation factor (g) and thermodynamic parameters viz. enthalpy of activation (ΔH) and Gibbs free energy of activation (ΔG) have been determined, to confirm the formation of hydrogen bonded homogeneous and heterogeneous cooperative domains, the dynamics of solute - solute interaction and the hindrance to molecular rotation in the hydrogen bonded glass forming ethylene glycol - dimethyl sulphoxide system.


Gupta V.K.,Microwave Research Laboratory | Sharma N.,Microwave Research Laboratory | Jangid R.A.,Microwave Research Laboratory
Indian Journal of Radio and Space Physics | Year: 2013

Dielectric constant (ε') and dielectric loss (ε") of artificially moistened soil of Alwar have been determined at microwave frequency 9.78 GHz and at temperature 32.5oC using wave guide cell method. In view of the active and passive microwave remote sensing, the horizontal-horizontal radar backscattering coefficient (σ0 hh) for bare and vegetative soil surface have been estimated by Integral Equation Model (IEM) and Water Cloud Model (WCM), respectively using ε' and ε"of soil and view angle as input parameters. The horizontal component of microwave emissivity (eh) for bare soil surfaces have been determined by emissivity model. The eh for vegetative soil surfaces determined by radiative transfer equation using suitable vegetation dependent parameters, like single way vegetation transmissivity (γ) and single scattering albedo (ω) for agricultural vegetation, respectively. The present study reveals that the σ0 hh for bare and vegetative soil surface exhibit a positive correlation with soil moisture content (SMC). Vegetative soil surface σ0 hh is lower than that of bare soil surface for the same values of SMC and view angle. Further, eh for bare and vegetative soil surfaces decreases with an increase in SMC. Vegetative soil surface emissivity is higher than that of bare surface for the same values of SMC and observation angle. Further, backscattering coefficient and emissivity for bare and vegetative soil surfaces decrease as the angle of observation increases due to contribution of diminished coherent component.


Undre P.B.,Dr Bam University | Khirade P.W.,Dr Bam University | Rajenimbalkar V.S.,Microwave Research Laboratory | Helambe S.N.,Microwave Research Laboratory | Mehrotra S.C.,Dr Bam University
Physics and Chemistry of Liquids | Year: 2012

Dielectric relaxation measurements on binary mixtures of dimethylacetamide with ethylene glycol and dimethylsulphoxide have been carried out at 11 concentrations using time domain reflectometry technique at 10°C, 20°C, 30°C and 40°C over the frequency range from 10 MHz to 10 GHz. For all the mixtures, only one dielectric loss peak is observed in this frequency range. The relaxation in these mixtures can be described by a single relaxation time using the Debye model. A systematic variation is observed in dielectric constant and relaxation time. Excess permittivity, excess inverse relaxation time, Kirkwood correlation factor and thermodynamic parameters such as enthalpy of activation and Gibbs free energy of activation have been determined, to confirm the formation of hydrogen-bonded homogeneous and heterogeneous cooperative domains, the dynamics of solute-solvent interaction and the hindrance to molecular rotation in the hydrogen-bonded glass forming ethylene glycol-dimethylacetamide and dimethylsulphoxide-dimethylacetamide system. © 2012 Copyright Taylor and Francis Group, LLC.

Loading Microwave Research Laboratory collaborators
Loading Microwave Research Laboratory collaborators