scholarly journals Relaxation Dynamics of Ethanol and N-Butanol in Diesel Fuel Blends from Terahertz Spectroscopy

2021 ◽  
Vol 42 (7) ◽  
pp. 772-792
Author(s):  
Rayda Patiño-Camino ◽  
Alexis Cova-Bonillo ◽  
José Rodríguez-Fernández ◽  
Teresa P. Iglesias ◽  
Magín Lapuerta
Keyword(s):  
Dielectric Constant ◽  
Relaxation Time ◽  
Full Range ◽  
Pure Component ◽  
Complex Dielectric Constant ◽  
Relaxation Processes ◽  
Relaxation Dynamics ◽  
Terahertz Time Domain Spectroscopy ◽  
Ideal Behavior ◽  
The Real

AbstractBinary blends of ethanol-diesel, n-butanol-diesel, ethanol-biodiesel, and n-butanol-biodiesel have been analyzed with terahertz time-domain spectroscopy in a full range of concentrations and at room temperature. The real and imaginary parts of the complex dielectric constant of the blends were obtained from the spectra and fitted to the Debye model at low volume concentrations (up to 7.5% for ethanol in diesel and up to 20% for butanol in diesel, ethanol in biodiesel, and butanol in biodiesel blends), considering the number of relaxation processes recommended in the literature for each pure component (single for diesel, double for biodiesel, and triple for alcohols). The results indicate that the faster relaxation time in low alcohol mixtures is longer than in pure alcohols. This relaxation time increases as the alcohol content increases. The excess of the real and of imaginary parts of the dielectric constant were individually determined. The analysis of such excess and of its different contributions (volume, contrast, and interactions) suggests that the intermolecular interactions between the different components of the blends dominate the relaxation dynamics in each pseudo-binary system. Ethanol was found to move blends further away from ideal behavior than n-butanol. In fact, these latter blends showed the most ideal behavior, suggesting that the length of the alcohol carbon chain plays an important role. This information allows a possible link between the nonlinear behavior of the physicochemical properties of the blends (e.g., viscosity and surface tension) and the molecular interactions between their constituent molecules. This relation could have direct application for monitoring the fuel composition and quality in the vehicle control systems.

DIELECTRIC RELAXATION IN LIQUIDS: I. THE REPRESENTATION OF RELAXATION BEHAVIOR

1961 ◽  
Vol 39 (3) ◽  
pp. 571-594 ◽  
Author(s):  
D. W. Davidson
Keyword(s):  
Dielectric Constant ◽  
Dielectric Relaxation ◽  
Superposition Principle ◽  
Relaxation Behavior ◽  
Complex Dielectric Constant ◽  
Published Data ◽  
Relaxation Processes ◽  
High Frequencies ◽  
Arc Characteristics ◽  
The Individual

Methods are described for the determination from experimental data of the parameters used in the skewed-arc representation in the complex dielectric constant plane of dielectric relaxation in liquids. Graphs give the frequency dependence of the real and imaginary parts of the dielectric constant predicted by the skewed-arc equation. Evidence, which includes an analysis of published data and of some new data, is presented for the frequent occurrence of this type of relaxation behavior in liquids. The resolution of the effects of different relaxation processes is discussed.The recent defect-diffusion model of Glarum is found to lead, under some conditions, to complex dielectric constant loci which are practically indistinguishable from skewed-arc loci over much of the frequency range of dispersion. It predicts departures from skewed-arc behavior at relatively high frequencies which are possibly related to experimentally observed departures.It is concluded that skewed-arc characteristics arise from the presence of co-operative relaxation processes, possibly aided by the diffusion of disordered regions, in which the individual mechanisms of relaxation cannot be resolved by application of the superposition principle.

DIELECTRIC RELAXATION IN CLAYS SATURATED WITH WATER-OIL EMULSION IN A WIDEBAND OF FREQUENCIES AT POSITIVE AND NEGATIVE TEMPERATURES

2021 ◽  
pp. 96-108
Author(s):  
A. V. Repin
Keyword(s):  
Dielectric Constant ◽  
Wide Frequency Range ◽  
Complex Dielectric Constant ◽  
Relaxation Processes ◽  
Frequency Range ◽  
Water Emulsion ◽  
Oil Emulsion ◽  
Negative Temperatures ◽  
Oil Water ◽  
Account Relaxation

The results of measuring the complex dielectric constant of clays saturated with an oil-water emulsion in various ratios in a wide frequency range are presented. The measurements were used out at positive and negative temperatures. It was revealed that several relaxation processes are observed in the spectra. The processes parameters significantly depend on the temperature and the ratio of water and hydrocarbon to the saturating mixture. A model is proposed that makes it possible to take into account relaxation processes and their dependence on temperature.

scholarly journals CHARGE CARRIERS TRANSPORT AND PERMITTIVITY OF SIO2 FILMS WITH INSB NANOPARTICLES

2020 ◽  
Author(s):  
Pawel Zukowsk ◽  
Tomasz Koltunowicz ◽  
Karolina Czarnacka ◽  
Alexander Fedotov ◽  
Ida Tyschenko
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Phase Angle ◽  
Exponential Decay ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Charge Carriers ◽  
Complex Dielectric Constant ◽  
Sio2 Films ◽  
The Real

A.c. current conductivity, capacitance, phase angle and dielectric loss tangent were studied for MOS SOI structures with ion-synthesized in the buried SiO2 layer InSb nanoparticles. Films conductivity nature change was detected at the temperature Т=200К. An exponential decay of the real and imaginary parts of the films complex dielectric constant was found.

Broadband Dielectric Relaxation of Polymer Composite Films

2000 ◽  
Vol 628 ◽  
Author(s):  
C.K. Chiang ◽  
Roman Popielarz ◽  
Ryusuke Nozaki ◽  
Jan Obrzut
Keyword(s):  
Dielectric Constant ◽  
Relaxation Time ◽  
Composite Materials ◽  
Wireless Communication ◽  
Dielectric Relaxation ◽  
Polymer Composite ◽  
Electronic Devices ◽  
Composite Films ◽  
Dielectric Behavior ◽  
Complex Dielectric Constant

ABSTRACTThe broadband dielectric relaxation of a BaTiO3-polymer composite film was studied. The complex dielectric constant data from 10-4 Hz to 1010 Hz reveals the existence of relaxation process at frequency of 10 MHz in the polymer composite. On the basis of Cole-Cole analysis, the relaxation time of the system is of order of 10-8 s. The understanding of the broad dispersion in dielectric behavior of polymer composite materials is needed to support next generation electronic devices used in wireless communication and related applications.

scholarly journals Complex Refractive Index of Strontium Titanate in the Terahertz Frequency Range

2019 ◽  
Vol 7 (4) ◽  
pp. 71-80 ◽  
Author(s):  
V. R. Bilyk ◽  
K. A. Grishunin
Keyword(s):  
Dielectric Constant ◽  
Refractive Index ◽  
Strontium Titanate ◽  
Time Domain ◽  
Complex Refractive Index ◽  
Complex Dielectric Constant ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Time Domain Spectroscopy ◽  
Terahertz Frequency Range

The recent progress in terahertz time-domain spectroscopy enables the accurate and reliable measurements of dielectric properties in comparison with the traditional far-infrared spectroscopy using an incoherent light source. The broadband THz-TDS is a powerful tool to determine the real and imaginary parts of a complex dielectric constant by the transmission which allows to detect the parameters of the soft modes in ferroelectrics. In this work, the terahertz time-domain spectroscopy was used to investigate the dependence of the complex refractive index of a single-crystal quantum paraelectric strontium titanate in the terahertz frequency range from 0.3 to 2 THz. It was shown that the low-frequency terahertz response of the material is determined by the soft phonon mode TO1. The measured experimental dependences showed a good agreement with the theoretical curves obtained from the analysis of the Lorentz oscillator model for the complex dielectric constant of strontium titanate. The obtained results are necessary for understanding the principle of possibility to manipulate the order parameter in ferroelectric materials and can be used to create energy-efficient memory devices with a speed of recording information close to the theoretical limit.

Investigation of Dielectric Properties, Electric Modulus and Conductivity of the Au/Zn-Doped PVA/n-4H-SiC (MPS) Structure Using Impedance Spectroscopy Method

2020 ◽  
Vol 234 (3) ◽  
pp. 505-516 ◽  
Author(s):  
Havva Elif Lapa ◽  
Ali Kökce ◽  
Ahmet Faruk Özdemir ◽  
Şemsettin Altındal
Keyword(s):  
Impedance Spectroscopy ◽  
Electric Modulus ◽  
Forward Bias ◽  
Spectroscopy Method ◽  
Complex Dielectric Constant ◽  
Relaxation Processes ◽  
Low Frequencies ◽  
High Frequencies ◽  
The Real ◽  
Wide Range

AbstractThe 50 nm thickness Zn-doped polyvinyl alcohol (PVA) was deposited on n-4H-SiC semiconductor as interlayer by electro-spinning method and so Au/Zn-doped PVA/n-4H-SiC metal-polymer-semiconductor (MPS) structure were fabricated. The real and imaginary parts of the complex dielectric constant (ε′, ε′′), loss-tangent (tan δ), the real and imaginary parts of the complex electric modulus (M′, M′′) and ac electrical conductivity (σac) behavior of this structure were examined using impedance spectroscopy method in a wide range of frequency (1 kHz–400 kHz) and voltage (−1 V)–(+6 V) at room temperature. The values of ε′, ε′′, tan δ, M′, M′′ and σac are determined sensitive to the frequency and voltage in depletion and accumulation regions. The values of ε′ and ε′′ decrease with increasing frequency while the values of M′ and σac increase. The peak behavior in the tan δ and M′′ vs. frequency curves was attributed to the dielectric relaxation processes and surface states (Nss). The plots of ln (σac) vs. ln (f) at enough high forward bias voltage (+6 V) have three linear regions with different slopes which correspond to low, intermediate and high frequencies, respectively. The dc conductivity is effective at low frequencies whereas the ac conductivity effective at high frequencies. According to experimental results, the surface/dipole polarizations can occur more easily occur at low frequencies and the majority of Nss between Zn-doped PVA and n-4H-SiC contributes to the deviation of dielectric behavior of this structure.

THE COMPLEX DIELECTRIC CONSTANT AT LOW MICROWAVE FREQUENCIES OF ETHYL CHLORIDE ADSORBED ON POROUS VYCOR GLASS

1961 ◽  
Vol 39 (3) ◽  
pp. 425-442 ◽  
Author(s):  
J. D. McCowan ◽  
R. McIntosh
Keyword(s):  
Dielectric Constant ◽  
Coaxial Line ◽  
Ethyl Chloride ◽  
Complex Dielectric Constant ◽  
Frequency Range ◽  
Vycor Glass ◽  
Microwave Frequencies ◽  
The Real ◽  
Porous Vycor Glass ◽  
Accuracy Of Measurement

The complex dielectric constant of the system Vycor glass – ethyl chloride has been measured at three temperatures in the range +11 °C to −33 °C and in the frequency range between 500 Mc sec−1 and 4000 Mc sec−1 by the use of a coaxial line. The real and imaginary parts of the dielectric constant of the adsorbate have also been evaluated. Appreciable loss in the adsorbed matter is found for small quantities adsorbed, and loss is again detected at the highest frequencies and lowest temperatures for the matter held in multilayers or condensed in capillaries. The frequency range and accuracy of measurement were not sufficient to classify the type of loss curve, but other evidence suggests that the loss for the first quantities adsorbed will turn out to be that for rotational oscillators. In general earlier observations of this system are confirmed and extended.

scholarly journals Determination of the complex dielectric permeability of liquid at the radiation frequency 32 GHz

2021 ◽  
Vol 1198 (1) ◽  
pp. 012012
Author(s):  
B G Tsydypov ◽  
A V Bazarov ◽  
B V Basanov ◽  
B Z Garmaev ◽  
E Yu Korovin ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Reflection Coefficient ◽  
Imaginary Part ◽  
Dielectric Permeability ◽  
Complex Dielectric Constant ◽  
Radiation Frequency ◽  
Layer Depth ◽  
The Real

Abstract Method and device for measuring the complex dielectric constant of liquids are described. The real part of the complex dielectric constant calculated from the conditions for the maximum and minimum of the measured interference dependence of the reflection coefficient on the layer depth. The imaginary part determined by selection to the maximum coincidence of the calculated and measured dependences of the reflection coefficient.

THE INFLUENCE OF THE SALTITY OF THE MOISTURIZING SOLUTION ON THE DIELECTRIC PERMEABILITY OF CLAYS IN THE FREQUENCY RANGE FROM 1 MHZ TO 8 GHZ

2021 ◽  
pp. 92-101
Author(s):  
A. V. Repin ◽  
O. V. Rodionova
Keyword(s):  
Dielectric Constant ◽  
Salt Solution ◽  
Dielectric Permeability ◽  
Wide Frequency Range ◽  
Complex Dielectric Constant ◽  
Relaxation Processes ◽  
Nacl Solution ◽  
Frequency Range

The article presents the results of measurements of the complex dielectric constant of clays saturated with NaCl solution of various concentrations in a wide frequency range. The measurements were carried out at positive temperatures. It was revealed that several relaxation processes are observed in the spectra. A model is proposed that makes it possible to take into account the relaxation processes and their dependence on the concentration of the salt solution. The concentration practically does not affect the parameters of the processes, in contrast to the temperature.

COMPLEX DIELECTRIC CONSTANT OF CIS-DICHLOROETHYLENE IN THE MICROWAVE-FREQUENCY REGION

1967 ◽  
Vol 45 (5) ◽  
pp. 1617-1620
Author(s):  
G. P. Srivastava ◽  
P. C. Mathur
Keyword(s):  
Dielectric Constant ◽  
Dipole Moment ◽  
Relaxation Time ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Microwave Frequency ◽  
Frequency Region ◽  
Complex Dielectric Constant ◽  
Dilute Solutions ◽  
X Band

The relaxation time and dipole moment of cis-dichloroethylene has been determined in the X-band microwave-frequency region from its dilute solutions in a nonpolar solvent. The dielectric loss tangent δ is found to vary linearly with concentration only for very dilute solutions.

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