Dielectric relaxation study of glycine–water mixtures using time domain reflectometry technique

Talware, Ravindra B.; Hudge, P. G.; Joshi, Y.S.; Kumbharkhane, A.C.

doi:10.1080/00319104.2010.551345

Cited by 7 publications

(3 citation statements)

References 14 publications

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“…The microwave heating efficiency in these types of binary system has been shown to depend significantly on the nonideality of the mixture, where higher heating rates are obtained for compositions at which negative deviations from the ideal solution are observed and intermolecular interactions are weaker . The amount of experimental work in this area is significant and includes systems such as alcohol/water, − glycine/water, , DMSO/alcohol, and mixtures of acetone, DMSO, and isopropanol . Other authors have investigated the dielectric response of aqueous solutions of α- d -glucose, , lysine, and nucleotides, mixtures of acrylic esters and alcohols, ionic liquids in water and ethanol, and p -fluorophenyl acetonitile/2-butylphenol and 2-chlor-6-fluoro-benzaldehyde/ o -ethylphenol systems .…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Investigation of the Influence of the Hydrogen Bond Networks in Ethanol/Water Mixtures on Dielectric Spectra

2018

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The dielectric response of fluids to electromagnetic radiation in the microwave region originates from processes occurring at the molecular level. Understanding these processes in more detail is relevant to many fields, such as microwave heating, fluid mixing, and separation technologies. In this work, we use molecular dynamics (MD) simulations to study the dielectric spectra of ethanol/water mixtures. We compare our predictions with experimental results at different compositions. We show how the dielectric response can be estimated to a high level of accuracy using three dielectric relaxations: a dominant and slower process at microwave frequencies and two faster processes. A deeper study of the dynamics of the hydrogen bond network formed in these systems reveals how collective processes between the individual species are the origin of the final dielectric response. Our results agree with the "wait-and-switch" mechanism, which describes the dynamics of the hydrogen bond network as the combination of two processes: the fast breakage and formation of individual hydrogen bonds and the subsequent reorganization of the entire network once this process becomes energetically favorable. Since the dielectric response is related to dipole reorientations in the system, it is directly linked to these mechanisms.

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Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Investigation of the Influence of the Hydrogen Bond Networks in Ethanol/Water Mixtures on Dielectric Spectra

2018

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“…The dielectric properties of glycine solutions have been studied in the VHF regime, but properties of prostatic tissue have not been reported. Relative permittivity of 0.2 M glycine solution at room temperature has been reported ranging from 78 – 10 j [36] to 90.35 – 0.1 j [37], with negligible conductivity due to ionic content. We model the spectrum of prostatic tissue using the relative permittivity of heart muscle but the electrical conductivity of blood and plasma.…”

Section: Fig A1mentioning

confidence: 99%

Toward Quantitative Whole Organ Thermoacoustics With a Clinical Array Plus One Very Low-Frequency Channel Applied to Prostate Cancer Imaging

Patch

Hull²,

See

et al. 2016

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Thermoacoustics has the potential to provide quantitative images of intrinsic tissue properties, most notably electrical conductivity in Siemens/meter, much as shear wave elastography provides tissue stiffness in kPa. Although thermoacoustic imaging with optical excitation has been commercialized for small animals, it has not yet made the transition to clinic for whole organ imaging in humans. The purpose of this work was to develop and validate specifications for a clinical ultrasound array for quantitative whole organ thermoacoustic imaging. Imaging a large organ requires exciting thermoacoustic pulses throughout the volume and broadband detection of those pulses because tomographic image reconstruction preserves frequency content. Applying the half-wavelength limit to a 200-micron inclusion inside a 7.5 cm diameter organ requires measurement sensitivity to frequencies ranging from 4 MHz down to 10 kHz, respectively. A dual-transducer system utilizing a P4-1 array connected to a Verasonics V1 system as well as a focused single element transducer sensitive to lower frequencies was developed. Very high frequency (VHF) irradiation generated thermoacoustic pulses throughout a 6 × 6 × 5 cm3 volume. In the VHF regime, electrical conductivity drives thermoacoustic signal production. Simultaneous acquisition of thermoacoustic pulses by both transducers enabled comparison of transducer performance. Data from the clinical array generated a stack of 96-images with separation of 0.3 mm, whereas the single element transducer imaged only in a single plane. In-plane resolution and quantitative accuracy were quantified at isocenter. The array provided volumetric imaging capability with superior resolution whereas the single element transducer provided superior quantitative accuracy in axial images. Combining axial images from both transducers preserved resolution of the P4-1 array and improved image contrast. Neither transducer was sensitive to frequencies below 50 kHz, resulting in a DC offset and low-frequency shading over fields of view exceeding 15 mm. Fresh human prostates were imaged ex vivo and volumetric reconstructions reveal structures rarely seen in diagnostic images. In conclusion, quantitative whole-organ thermoacoustic tomography will be feasible by sparsely interspersing transducer elements sensitive to the low end of the ultrasonic range.

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“…21,22 The Tektronix model no. DSA8200 Digital Serial Analyzer sampling mainframe along with the sampling module 80E08 has been used for the TDR.…”

Section: Materials and Measurementsmentioning

confidence: 99%

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

Swami¹,

Hudge

Pawar³

2016

J. Adv. Dielect.

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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 (" 0 ), dielectric constant at high frequency (" 1 ), relaxation time (ps) and relaxation distribution parameter () were extracted from complex permittivity spectra at 25 C. The intramolecular interaction of different molecules has been discussed using the Kirkwood correlation factor, Bruggeman factor. The Kirkwood correlation factor (g f ) and effective Kirkwood correlation factor (g eff ) indicate the dipole ordering of the binary mixtures.

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Dielectric relaxation study of glycine–water mixtures using time domain reflectometry technique

Cited by 7 publications

References 14 publications

Molecular Dynamics Investigation of the Influence of the Hydrogen Bond Networks in Ethanol/Water Mixtures on Dielectric Spectra

Molecular Dynamics Investigation of the Influence of the Hydrogen Bond Networks in Ethanol/Water Mixtures on Dielectric Spectra

Toward Quantitative Whole Organ Thermoacoustics With a Clinical Array Plus One Very Low-Frequency Channel Applied to Prostate Cancer Imaging

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

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