DUAL COAXIAL PROBES IN TRANSMISSION INSERTED BY DIELECTRIC WITH TWO DIFFERENT THICKNESSES TO EXTRACT THE MATERIAL COMPLEX RELATIVE PERMITTIVITY: DISCONTINUITY IMPACTS

Dependence of ET(30) of solvent parameters on relative permittivity (ε) and refractive index (n) of solvent has been found for forty solvents in the form ET(30)=29.87 + 72.03 (ε - 1/(2ε + 1)-29.16(ε - 1) (n 2 - 1)/(2ε + 1) (2n2 + 1), the correlation coefficient being 0.958. Relation has been discussed between ET(30) and π solvent parameters and significance of the term (ε - 1). (n2 - 1)/(2ε + 1) (2n2 + 1) has been tested for evaluation of solvent effects in electronic spectra.>

Download Full-text

Human Orosomucoid: Dissociation of Tyrosines in the Systems Water-Low Aliphatic Alcohol

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19971533 ◽

1997 ◽

Vol 62 (10) ◽

pp. 1533-1543

Author(s):

Vladimír Karpenko ◽

Jana Horálková ◽

Milan Kodíček

Keyword(s):

Human Serum ◽

Systems Analysis ◽

Titration Curve ◽

Relative Permittivity ◽

Structural Changes ◽

Aliphatic Alcohol ◽

Mixed Media ◽

Spectrophotometric Titration ◽

Electrostatic Effects

The influence of methanol, ethanol, propan-1-ol, and propan-2-ol on the dissociation of tyrosines of human serum orosomucoid (acid α1-glycoprotein) was studied. The content of alcohols was chosen so that their solutions had the same value of the relative permittivity. Then, the contribution of electrostatic effects was equal in all cases and the observed differences between aqueous and alcoholic solutions reflected other, nonelectrostatic effects in the studied systems. Analysis of the spectrophotometric titration curve revealed three kinds of tyrosine groups (n1, n2, n3), but only the values pK1 and pK2 could be calculated. The observed differences of pK values in aqueous and mixed media are discussed and compared with the structural changes of the orosomucoid molecule.

Download Full-text

Computational modeling of poled and unpoled barium titanate to determine the influence of relative permittivity and piezoelectric constant

Ferroelectrics ◽

10.1080/00150193.2021.1916346 ◽

2021 ◽

Vol 577 (1) ◽

pp. 13-23

Author(s):

Shadeeb Hossain

Keyword(s):

Barium Titanate ◽

Computational Modeling ◽

Relative Permittivity ◽

Piezoelectric Constant

Download Full-text

Performance of Reconfigurable Antenna Fabricated on Flexible and Nonflexible Materials for Band Switching Applications

Energies ◽

10.3390/en14092553 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2553

Author(s):

B. R. Sanjeeva Reddy ◽

Naresh K. Darimireddy ◽

Chan-Wang Park ◽

Abdellah Chehri

Keyword(s):

Relative Permittivity ◽

Ground Layer ◽

Reconfigurable Antenna ◽

Textile Antenna

In this article, a novel frequency slot-based switchable antenna fabricated on flexible and nonflexible materials is presented for suitable reconfigurable radiations of Bluetooth, WiMAX, and upper WLAN applications. Initially, the performance of this structure was simulated using a CSTTM simulator and evaluated experimentally using a nonflexible FR4 structure. The same antenna was implemented on a flexible (jean) substrate with a relative permittivity of 1.7. The proposed textile antenna prototypes were fabricated by optimal dimensions of an E-shaped slot with a variation on the shape of the ground layer, integrated using a crossed T-shaped strip with ON/OFF switchable state operations. The proposed antenna prototype is compact (20 × 20 mm2), providing switchable radiations with tri bands, has frequencies ranged at 2.36–2.5 GHz for Bluetooth, 3.51–3.79 GHz and 5.47–5.98 GHz for the distinct bands of WiMAX and WLAN, respectively, as well as part of UWB operations.

Download Full-text

Photon-magnon response to fluid variability and saturation levels in sandstone reservoirs

Journal of Geophysics and Engineering ◽

10.1093/jge/gxaa064 ◽

2020 ◽

Vol 17 (6) ◽

pp. 1065-1074

Author(s):

Abdullah Musa Ali ◽

Amir Rostami ◽

Noorhana Yahya

Keyword(s):

Oil Recovery ◽

Relative Permittivity ◽

Wave Interaction ◽

Heterogeneous Porous Media ◽

Injection System ◽

Bragg Grating ◽

Fibre Bragg Grating ◽

Core Flooding ◽

Oil Saturation ◽

Fluid Saturation

Abstract The need to recover high viscosity heavy oil from the residual phase of reservoirs has raised interest in the use of electromagnetics (EM) for enhanced oil recovery. However, the transformation of EM wave properties must be taken into consideration with respect to the dynamic interaction between fluid and solid phases. Consequently, this study discretises EM wave interaction with heterogeneous porous media (sandstones) under different fluid saturations (oil and water) to aid the monitoring of fluid mobility and activation of magnetic nanofluid in the reservoir. To achieve this aim, this study defined the various EM responses and signatures for brine and oil saturation and fluid saturation levels. A Nanofluid Electromagnetic Injection System (NES) was deployed for a fluid injection/core-flooding experiment. Inductance, resistance and capacitance (LRC) were recorded as the different fluids were injected into a 1.0-m long Berea core, starting from brine imbibition to oil saturation, brine flooding and eventually magnetite nanofluid flooding. The fluid mobility was monitored using a fibre Bragg grating sensor. The experimental measurements of the relative permittivity of the Berea sandstone core (with embedded detectors) saturated with brine, oil and magnetite nanofluid were given in the frequency band of 200 kHz. The behaviour of relative permittivity and attenuation of the EM wave was observed to be convolutedly dependent on the sandstone saturation history. The fibre Bragg Grating (FBG) sensor was able to detect the interaction of the Fe3O4 nanofluid with the magnetic field, which underpins the fluid mobility fundamentals that resulted in an anomalous response.

Download Full-text