scholarly journals Dielectric Relaxation and Thermodynamic Study of Caffeine-Chloroform Solution using TDR

2021 ◽  
Vol 9 (VII) ◽  
pp. 3870-3874
Author(s):  
A. R. Lathi
Keyword(s):  
Dielectric Constant ◽  
Relaxation Time ◽  
Time Domain ◽  
Complex Permittivity ◽  
Chloroform Solution ◽  
Time Domain Reflectometry ◽  
Least Square ◽  
Enthalpy Of Activation ◽  
Least Square Fit ◽  
Entropy Of Activation

The Complex permittivity of caffeine – Chloroform solution for different temperature and various concentrations have been measured in the range of 10MHZ to 30 GHz using Time Domain Reflectometry. From complex permittivity spectra, Static dielectric constant (εo) and relaxation time (τ) were determined using nonlinear least square fit method. Using Erying rate equation, for different molar concentration of caffeine Enthalpy of Activation ∆H and Entropy of Activation ∆S were determined.

scholarly journals Dielectric properties of benzylamine in 1,2,6-hexanetriol mixture using time domain reflectometry technique

2016 ◽  
Vol 06 (04) ◽  
pp. 1650034
Author(s):  
M. B. Swami ◽  
P. G. Hudge ◽  
V. P. Pawar
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Binary Mixtures ◽  
Time Domain ◽  
Complex Permittivity ◽  
Intramolecular Interaction ◽  
Correlation Factor ◽  
Time Domain Reflectometry ◽  
Least Square ◽  
Kirkwood Correlation Factor

The dielectric properties of binary mixtures of benzylamine-1,2,6-hexantriol mixtures at different volume fractions of 1,2,6-hexanetriol have been measured using Time Domain Reflectometry (TDR) technique in the frequency range of 10 MHz to 30 GHz. Complex permittivity spectra were fitted using Havriliak–Negami equation. By using least square fit method the dielectric parameters such as static dielectric constant ([Formula: see text]), dielectric constant at high frequency ([Formula: see text]), relaxation time [Formula: see text] (ps) and relaxation distribution parameter ([Formula: see text]) were extracted from complex permittivity spectra at 25[Formula: see text]C. The intramolecular interaction of different molecules has been discussed using the Kirkwood correlation factor, Bruggeman factor. The Kirkwood correlation factor ([Formula: see text]) and effective Kirkwood correlation factor ([Formula: see text]) indicate the dipole ordering of the binary mixtures.

scholarly journals Dielectric Relaxation Studies of 2-Butoxyethanol with Aniline and Substituted Anilines Using Time Domain Reflectometry

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
P. Jeevanandham ◽  
S. Kumar ◽  
P. Periyasamy ◽  
A. C. Kumbharkhane
Keyword(s):  
Dielectric Constant ◽  
Relaxation Time ◽  
Liquid Mixtures ◽  
Correlation Factor ◽  
Time Domain Reflectometry ◽  
Least Square ◽  
Substituted Anilines ◽  
Dielectric Parameters ◽  
Kirkwood Correlation Factor ◽  
Least Square Fit

The complex dielectric spectra of 2-butoxyethanol with aniline and substituted anilines like aniline, o-chloroaniline, m-chloroaniline, o-anisidine and m-anisidine binary mixtures in the composition of different volumes of percent (0%, 25%, 50%, 75%, and 100%) have been measured as a function of frequency between 10 MHz and 30 GHz at 298.15 K. The dielectric parameters like static dielectric constant ε0 and relaxation time τ have been obtained by using least square fit method. By using these parameters ε0,τ, effective Kirkwood correlation factor geff, corrective Kirkwood correlation factor gf, Bruggeman factor fB, excess dielectric constant εE, and excess inverse relaxation time 1/τE values are calculated and discussed to yield information on the dipolar alignment and molecular rotation of the binary liquid mixtures. From all the derived dielectric parameters, molecular interactions are interpreted through hydrogen bonding.

scholarly journals Dielectric relaxation studies of binary mixture of β-picoline and methanol using time domain reflectometry at different temperatures

2016 ◽  
Vol 06 (03) ◽  
pp. 1650022 ◽  
Author(s):  
C. M. Trivedi ◽  
V. A. Rana ◽  
P. G. Hudge ◽  
A. C. Kumbharkhane
Keyword(s):  
Relaxation Time ◽  
Dielectric Relaxation ◽  
Time Domain ◽  
Complex Permittivity ◽  
Time Domain Reflectometry ◽  
Least Square ◽  
Static Permittivity ◽  
Inverse Relaxation Time ◽  
Model Complex ◽  
Excess Inverse Relaxation Time

Complex permittivity spectra of binary mixtures of varying concentrations of [Formula: see text]-picoline and Methanol (MeOH) have been obtained using time domain reflectometry (TDR) technique over frequency range 10 MHz to 25 GHz at 283.15, 288.15, 293.15 and 298.15 K temperatures. The dielectric relaxation parameters namely static permittivity ([Formula: see text]), high frequency limit permittivity ([Formula: see text]) and the relaxation time ([Formula: see text]) were determined by fitting complex permittivity data to the single Debye/Cole-Davidson model. Complex nonlinear least square (CNLS) fitting procedure was carried out using LEVMW software. The excess permittivity ([Formula: see text]) and the excess inverse relaxation time (1/[Formula: see text] which contain information regarding molecular structure and interaction between polar–polar liquids were also determined. From the experimental data, parameters such as effective Kirkwood correlation factor (geff), Bruggeman factor (fB) and some thermo dynamical parameters have been calculated. Excess parameters were fitted to the Redlich–Kister polynomial equation. The values of static permittivity and relaxation time increase nonlinearly with increase in the mol–fraction of MeOH at all temperatures. The values of excess static permittivity ([Formula: see text]E) and the excess inverse relaxation time (1/[Formula: see text] are negative for the studied [Formula: see text]-picoline — MeOH system at all temperatures.

scholarly journals Dielectric spectroscopy and hydrogen bonding studies of 1-chloropropane–ethanol mixture using TDR technique

2019 ◽  
Vol 09 (02) ◽  
pp. 1950018 ◽  
Author(s):  
Ravindra V. Shinde ◽  
Avadhut R. Deshmukh ◽  
Shital A. Ingole ◽  
Ashok C. Kumbharkhane
Keyword(s):  
Relaxation Time ◽  
Dielectric Permittivity ◽  
Correlation Factor ◽  
Time Domain Reflectometry ◽  
Least Square ◽  
Dielectric Parameters ◽  
Structural Formation ◽  
Static Dielectric Permittivity ◽  
Least Square Fit ◽  
The Time Domain

The time-domain reflectometry technique was exercised to assess the complex permittivities of 1-chloropropane and ethanol along with their binary mixture in the frequency range of 10[Formula: see text]MHz–50[Formula: see text]GHz and in the temperature range of 10–[Formula: see text]C. Dielectric parameters like static dielectric permittivity ([Formula: see text] and relaxation time ([Formula: see text] have been acquired by the least-square-fit method. The obtained assessments of static permittivity and relaxation time were used to compute various dielectric parameters like excess dielectric constant, excess relaxation time, Kirkwood correlation factor and thermodynamic parameters. The experimental outcome illustrates the nonlinear variations in dielectric permittivity, relaxation time and authenticates the structural formation due to intermolecular interaction between 1-chloropropane and ethanol. Molecular rotary motion and dipole reorientation movements of these complex systems are presented in agreement with the molar entropy and enthalpy.

Evaluation of complex permittivity of aqueous solution by time domain reflectometry

1987 ◽  
Vol 36 ◽  
pp. 135-151 ◽  
Author(s):  
S. Mashimo ◽  
T. Umehara ◽  
T. Ota ◽  
S. Kuwabara ◽  
N. Shinyashiki ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Time Domain ◽  
Complex Permittivity ◽  
Time Domain Reflectometry

Impact of density on the hydraulic properties of peat and the time domain reflectometry (TDR) moisture calibration curve

2005 ◽  
Vol 42 (1) ◽  
pp. 279-286 ◽  
Author(s):  
Anushka Shibchurn ◽  
Paul J Van Geel ◽  
Paula L Kennedy
Keyword(s):  
Dielectric Constant ◽  
Soil Moisture ◽  
Water Content ◽  
Time Domain ◽  
Calibration Curve ◽  
Hydraulic Properties ◽  
Time Domain Reflectometry ◽  
Organic Soils ◽  
Dry Density ◽  
Water Contents

The hydraulic properties of a peat used in a commercial peat biofilter were evaluated to determine their relationship with density and to establish a time domain reflectometry (TDR) calibration curve for water content as a function of the measured dielectric constant. The peat studied was a milled Sphagnum peat with a high organic content (99%). The dry densities evaluated in this study ranged from 90 to 180 kg/m3. The saturated hydraulic conductivity (Ks) decreased with an increase in dry density (ρdry) and was found to follow a log-linear relationship (Ks = 0.2462 exp(–0.0438ρdry), correlation coefficient R2 = 0.9789). As expected, the soil moisture curve was impacted by density, with a higher density resulting in higher water contents for a given suction. The data were fit to the van Genuchten relationship. A TDR calibration curve was generated at five different densities. A comparison of the curves indicates that the water content as a function of dielectric constant was not dependent on density because of the significantly larger dielectric constant (Ka) of water compared with those of peat solids and air-filled voids. The TDR calibration curve for the peat evaluated in this study (volumetric water content Θv = 0.2667 ln(Ka) – 0.1405, R2 = 0.9564) predicted higher water contents for a given dielectric constant compared with those from similar calibration curves for peat published in the literature. The data were compared with those from six other studies and indicated that the TDR calibration varied for different organic soils. The density-dependent hydraulic parameters and TDR calibration curve are important parameters needed to study the hydraulics of peat biofilters.Key words: peat, TDR, time domain reflectometry, density, hydraulics, soil moisture.

Solvolysis of Sulphonyl Halides. I. The Hydrolysis of Aromatic Sulphonyl Chlorides in Aqueous Dioxan and Aqueous Acetone

1961 ◽  
Vol 14 (2) ◽  
pp. 190 ◽  
Author(s):  
FE Jenkins ◽  
AN Hambly
Keyword(s):  
Dielectric Constant ◽  
Reaction Rate ◽  
Acid Catalysis ◽  
Salt Effect ◽  
Aqueous Acetone ◽  
Low Dielectric Constant ◽  
Low Dielectric ◽  
Enthalpy Of Activation ◽  
Entropy Of Activation ◽  
Hydrolysis Of

The hydrolysis of benzene, p-toluene, p-bromobenzene, and p-nitrobenzene sulphonyl chlorides in 10-60 wt. % water-dioxan and water-acetone has been shown to follow an SN2 mechanism. The reaction does not show acid catalysis or any " salt " effect. Hammett?s equation does not describe fully the effects of substituents on the reaction rate. For solutions in which water has the same molarity, aqueous acetone gives lower rates than aqueous dioxan when the molarity of water is high but higher rates when the molarity of water is low. Change in the water content of the solvent produces only small changes in the enthalpy of activation except in solutions of low dielectric constant. The reduction in rate as solutions become less aqueous is mainly determined by the entropy of activation becoming more strongly negative.

scholarly journals Time domain reflectrometry measurements using a movable obstacle for the determination of dielectric profiles

2008 ◽  
Vol 6 ◽  
pp. 1-4
Author(s):  
B. Will ◽  
M. Gerding ◽  
S. Schultz ◽  
B. Schiek
Keyword(s):  
Dielectric Constant ◽  
Water Content ◽  
Time Domain ◽  
Measurement Techniques ◽  
Measurement Data ◽  
Time Domain Reflectometry ◽  
Dielectric Measurement ◽  
Effective Dielectric Constant ◽  
Pulse Delay

Abstract. Microwave techniques for the measurement of the permittivity of soils including the water content of soils and other materials, especially TDR (time domain reflectometry), have become accepted as routine measurement techniques. This summary deals with an advanced use of the TDR principle for the determination of the water content of soil along a probe. The basis of the advanced TDR technique is a waveguide, which is inserted into the soil for obtaining measurements of the effective soil permittivity, from which the water content is estimated, and an obstacle, which can mechanically be moved along the probe and which acts as a reference reflection for the TDR system with an exactly known position. Based on the known mechanical position of the reference reflection, the measured electrical position can be used as a measure for the effective dielectric constant of the environment. Thus, it is possible to determine the effective dielectric constant with a spatial resolution given by the step size of the obstacle displacement. A conventional industrial TDR-system, operating in the baseband, is used for the signal generation and for the evaluation of the pulse delay time of the obstacle reflection. Thus, a cost effective method for the acquisition of the dielectric measurement data is available.

scholarly journals Influência da Densidade na Estimativa da Umidade Volumétrica em um Latossolo Vermelho-Amarelo (Influence of Density in Estimation of Volumetric Moisture an Oxisol)

2013 ◽  
Vol 5 (5) ◽  
pp. 1056 ◽  
Author(s):  
Carlos Alexandre Barros de Almeida ◽  
Antonio Celso Dantas Antonino ◽  
Rejane Magalhaes de Mendonça Pimentel ◽  
Carlos Alberto Brayner de Oliveira Lira ◽  
José Romualdo de Sousa Lima
Keyword(s):  
Dielectric Constant ◽  
Soil Moisture ◽  
Bulk Density ◽  
Time Domain ◽  
Time Domain Reflectometry ◽  
Calibration Equation ◽  
Moisture Sensor ◽  
Soil Moisture Sensor ◽  
Volumetric Soil Moisture ◽  
Use Of Time

A estimativa da umidade volumétrica do solo pode ser realizada por vários métodos, entre eles destaca-se o uso da Reflectometria no Domínio do Tempo (TDR). Este tem como uso padrão, uma equação que relaciona a constante dielétrica do meio com a umidade sugerida pelo manual do fabricante. Este estudo objetivou avaliar a medição a umidade volumétrica do solo pelo sensor CS616. Na sua realização foi feita a calibração deste sensor em laboratório, para quatro camadas em um Latossolo Vermelho-Amarelo que apresentam densidades diferentes. Foram utilizados cinco métodos diferentes, três consagrados pela literatura e outros dois sugeridos por esse estudo. Os resultados permitiram concluir que nesse solo há uma grande disparidade entre os resultados encontrados durante a calibração do sensor e que a densidade do solo é um parâmetro importante nas medições de umidade do solo.Palavras-chave: reflectometria no domínio do tempo, medição direta da água no solo, equação de calibração Influence of Density in Estimation of Volumetric Moisture an Oxisol ABSTRACTThe estimation of volumetric soil moisture can be accomplished by various methods, among them stands out the use of Time Domain Reflectometry (TDR). This standard is to use an equation that relates the dielectric constant of the medium with humidity suggested by the manufacturer's manual. This study aimed to evaluate the measured volumetric soil moisture sensor for the CS616. In its realization was made to calibrate this sensor in the laboratory for four layers in an Latossolo Vermelho-Amarelo which have different densities. Was used five different methods, the literature established three and two others suggested by this study. The results showed that this soil there is great disparity between the results obtained during calibration of the sensor and the bulk density is an important parameter in measurements of soil moisture.Keywords: time domain reflectometry, direct measurement of soil water, calibration equation

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