scholarly journals Dielectric constant and induced dipole moment of edible oils subjected to conventional heating

2012 ◽  
Vol 31 (2) ◽  
pp. 285 ◽  
Author(s):  
Margareta Pecovska Gjorgjevich ◽  
Aleksandar Andonovski ◽  
Julijana Velevska
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Corn Oil ◽  
Edible Oils ◽  
Dipole Moments ◽  
Virgin Olive Oil ◽  
Peak Frequency ◽  
Conventional Heating ◽  
Orientation Polarization ◽  
Induced Dipole

The frequency dependence of dielectric constant, dielectric loss factor and conductivity are studied for five edible oils in the frequency range 100 kHz to 13 MHz at different temperatures using frequency domain spectroscopy. The dielectric constant is found similar for all the samples and in agreement with the previous reports. The dielectric loss is low (<0.01) except for the virgin olive oil with value of 0.05. Dielectric loss peak frequency is at  4 MHz for corn oil and around 5.2 MHz for the others. At this frequency conductivity is of the order of 10-7-10-9 S/cm, and decreases with temperature following the behavior of the dielectric losses. Refractive index, molar and orientation polarization are calculated for all types of oils using novel theory proposed by N. M. Putintsev and D. N. Putintsev [1]. Data show that the orientation polarization contributes to the observed dielectric constant at low temperatures and frequencies.  This indicates that the edible oils are not pure nonpolar dielectrics. Induced dipole moments of oils are calculated for 400 kHz and 10 MHz at 300 K and 318 K. The results are discussed and correlated as a function of temperature and frequency to establish their relationship.

scholarly journals Dielectric Properties of Vegetable Oils

2011 ◽  
Vol 3 (3) ◽  
pp. 481-492 ◽  
Author(s):  
Z. H. Shah ◽  
Q. A. Tahir
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Vegetable Oils ◽  
Polychlorinated Biphenyl ◽  
Corn Oil ◽  
Transformer Oil ◽  
International Electrotechnical Commission ◽  
Dielectric Data ◽  
Relaxation Polarization

In search of PCB (polychlorinated biphenyl) free mineral oil used in transformer, we have carried out the detailed study on dielectric properties of some vegetable oils, such as corn oil and cottonseed oil. Dielectric constant, dielectric loss factor have been determined for corn oil, cotton seed oil, and PCB free mineral transformer oil having International Electrotechnical Commission number IEC-60296 in the frequency range 330 Hz to 3 MHz and in temperature range 250C to 700C. The dielectric data of the vegetable oils is critically compared with that of the transformer oil and appropriate causes for similarities and differences have been discussed. Owing to comparable results in the vegetable oils and transformer oil studied, it is suggested that vegetable oils may also be used as transformer oil.Keywords: dielectric constant; dielectric loss; dielectric relaxation; polarization.© 2011 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi:103329/jsr.v3i3.7049                J. Sci. Res. 3(3), 491-502 (2011)

scholarly journals Atomic polarization in metal chelates. II. Dielectric loss measurements on some diketone chelates of tin(IV)

1973 ◽  
Vol 26 (4) ◽  
pp. 871 ◽  
Author(s):  
JW Hayes ◽  
WH Nelson ◽  
DV Radford
Keyword(s):  
Dielectric Loss ◽  
Dipole Moments ◽  
Relaxation Times ◽  
Metal Chelates ◽  
Atomic Polarization ◽  
Orientation Polarization

Dipole moments and relaxation times determined by dielectric loss measurements at 3.109 and 9.400 GHz are reported for bis(pentane-2,4- dionato)dimethyltin(IV) and its dimethyl and diphenyl analogues with tropolone. All of these compounds show true orientation polarization in accord with the assignment of cis structures. High atomic polarizations are observed in all cases and it is suggested that this may be a characteristic of metal chelates in general.

scholarly journals Evaluation of Extra Virgin Olive Oil Adulteration with Edible Oils using ATR-FTIR Spectroscopy

2020 ◽  
Vol 5 (1) ◽  
pp. 35-44
Author(s):  
Nuraznee Mashodi ◽  
Nurul Yani Rahim ◽  
Norhayati Muhammad ◽  
Saliza Asman
Keyword(s):  
Linear Regression ◽  
Olive Oil ◽  
Ftir Spectroscopy ◽  
Corn Oil ◽  
Edible Oils ◽  
Limit Of Detection ◽  
Linear Regression Analysis ◽  
Virgin Olive Oil ◽  
Extra Virgin Olive Oil ◽  
Regression Graph

Extra virgin olive oil (EVOO) is categorized as expensive oil due to high-quality nutritional value. Unfortunately, EVOO is easily adulterated with other low-quality edible oils. Therefore, this study was done to differentiate and analyze the adulteration of EVOO with other edible oils using Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy. The study was used several edible oils included canola oil, corn oil, sunflower oil, and soybean oil as an adulterant for EVOO. The adulterant EVOO samples were prepared by mixing with dissimilar concentrations of the solely edible oils (20 %, 40 %, 60 % and 80 % (v/v)). The main functional groups of EVOO and other edible oils are O-H, C-H, C=C and C=O groups were assigned around 3500 cm-1, 2925 cm-1, 3006 cm-1 and 1745 cm-1 wavenumbers, respectively. From the comparison of EVOO and other adulterant edibles oil spectra, it showed that the EVOO has the lowest absorbance intensity at around 3006 cm-1 represented double bond which is closely related to the composition of oil sample. The adulteration of EVOO was evaluated by analysing the changes in the absorbance based on the linear regression analysis graph of the bands at 3006 and 2925 cm-1 and the limit of detection (LOD) was measured. The graph of A3008/A2925 with good relative coefficients (R2) and lower LOD is more favourable than the linear regression graph of A3006 versus percentage of edible oils added in EVOO. This study showed that ATR-FTIR spectroscopy is a convenient tool for analysing the adulteration of EVOO.

scholarly journals Authenticity and Concentration Analysis of Extra Virgin Olive Oil Using Spontaneous Raman Spectroscopy and Multivariate Data Analysis

2019 ◽  
Vol 9 (12) ◽  
pp. 2433 ◽  
Author(s):  
Shiyamala Duraipandian ◽  
Jan C. Petersen ◽  
Mikael Lassen
Keyword(s):  
Raman Spectroscopy ◽  
Olive Oil ◽  
Rapeseed Oil ◽  
Corn Oil ◽  
Edible Oils ◽  
Virgin Olive Oil ◽  
Extra Virgin Olive Oil ◽  
Ternary Mixtures ◽  
Calibration Models ◽  
Oil Mixtures

Adulteration of extra virgin olive oil (EVOO) with cheaper edible oils is of considerable concern in the olive oil industry. The potential of Raman spectroscopy combined with multivariate statistics has been investigated for evaluating the authenticity (or purity) and concentration of EVOO irrespective of it being adulterated with one or more adulterants. The adulterated oil samples were prepared by blending different concentrations of EVOO (10–100% v/v) randomly with cheaper edible oils such as corn, soybean and rapeseed oil. As a result, a Raman spectral database of oil samples (n = 214 spectra) was obtained from 11 binary mixtures (EVOO and rapeseed oil), 16 ternary mixtures (EVOO, rapeseed and corn oil) and 44 quaternary mixtures (EVOO, rapeseed, corn and soybean oil). Partial least squares (PLS) calibration models with 10-fold cross validation were constructed for binary, ternary and quaternary oil mixtures to determine the purity of spiked EVOO. The PLS model on the complex dataset (binary + ternary + quaternary) where the spectra obtained with different measurement parameters and sample conditions can able to determine the purity of spiked EVOO inspite of being blended with one or more cheaper oils. As a proof of concept, in this study, we used single batch of commercial oil bottles for estimating the purity of EVOO. The developed method is not only limited to EVOO, but can be applied to clean EVOO obtained from the production site and other types of food.

scholarly journals Zusätzliche dielektrische Verluste starrer, polarer Moleküle in verdünnter Lösung bei Frequenzen oberhalb des Maximums der Debye-Absorption / Additional Dielectric Loss of Rigid Polar Molecules in Dilute Solutions at Frequencies in the Far Infrared [FIR]

1976 ◽  
Vol 31 (12) ◽  
pp. 1543-1550 ◽  
Author(s):  
W. Noerpel
Keyword(s):  
Dielectric Loss ◽  
Time Constant ◽  
Dipole Moments ◽  
Far Infrared ◽  
Polar Molecules ◽  
Dilute Solutions ◽  
Induced Dipole ◽  
Mm Waves

Abstract The dielectric loss of ten polar molecules in dilute solutions has been measured in the 0.3 GHz to 300 GHz range. Besides the Debye-absorption of the polar molecules, in all solvents, i.e. heptane, cyclohexane, mesitylene and decalin there could be separated an additional part of dielectric loss in the range of mm-waves. This absorption has been approximated by a Debye-curve to gain the step of dispersion and the time-constant. The dielectric loss of the unpolar solvents themselves, which is due to collision induced dipole moments, has also been investigated. The results are discussed and compared with the FIR-absorption of the polar molecules.

Main Dielectric Dispersion Region of Mixtures of some Long-Chain Alcohols with Non-Polar Solvents

1972 ◽  
Vol 27 (8-9) ◽  
pp. 1363-1367 ◽  
Author(s):  
F. F. Hanna ◽  
I. K. Hakim
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Dipole Moments ◽  
Relaxation Times ◽  
Dielectric Dispersion ◽  
Concentrated Solutions ◽  
Polar Solvents ◽  
Dispersion Region ◽  
Long Chain

Abstract The dielectric constant ε' and dielectric loss ε" are measured for concentrated solutions of n-dodecanol and n-octanol with five non-polar solvents at five frequencies between 2 and 400 MHz at three temperatures between 20 and 60 °C. The effective dipole moments have been calculated and found to decrease with increasing dilution. The relaxation times of the concentrated solutions are lower than that of the pure alcohols, decrease with dilution and are dependent on the nature of the non-polar solvents.

Skin–core structured fluorinated MWCNTs: a nanofiller towards a broadband dielectric material with a high dielectric constant and low dielectric loss

2018 ◽  
Vol 6 (9) ◽  
pp. 2370-2378 ◽  
Author(s):  
Yang Liu ◽  
Cheng Zhang ◽  
Benyuan Huang ◽  
Xu Wang ◽  
Yulong Li ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
High Dielectric Constant ◽  
Dielectric Material ◽  
Epoxy Composite ◽  
Low Dielectric ◽  
High Dielectric

A novel skin–core structured fluorinated MWCNT nanofiller was prepared to fabricate epoxy composite with broadband high dielectric constant and low dielectric loss.

Enhanced dielectric properties and thermostability in polyimide composites with core-shell structured polyimide@BaTiO3 nanoparticles

2021 ◽  
pp. 095400832199352
Author(s):  
Wei Deng ◽  
Guanguan Ren ◽  
Wenqi Wang ◽  
Weiwei Cui ◽  
Wenjun Luo
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Energy Density ◽  
Breakdown Strength ◽  
In Situ Polymerization ◽  
Dielectric Materials ◽  
High Energy ◽  
Amic Acid ◽  
High Energy Density ◽  
Core Shell

Polymer composites with high dielectric constant and thermal stability have shown great potential applications in the fields relating to the energy storage. Herein, core-shell structured polyimide@BaTiO3 (PI@BT) nanoparticles were fabricated via in-situ polymerization of poly(amic acid) (PAA) and the following thermal imidization, then utilized as fillers to prepare PI composites. Increased dielectric constant with suppressed dielectric loss, and enhanced energy density as well as heat resistance were simultaneously realized due to the presence of PI shell between BT nanoparticles and PI matrix. The dielectric constant of PI@BT/PI composites with 55 wt% fillers increased to 15.0 at 100 Hz, while the dielectric loss kept at low value of 0.0034, companied by a high energy density of 1.32 J·cm−3, which was 2.09 times higher than the pristine PI. Moreover, the temperature at 10 wt% weight loss reached 619°C, demonstrating the excellent thermostability of PI@BT/PI composites. In addition, PI@BT/PI composites exhibited improved breakdown strength and toughness as compared with the BT/PI composites due to the well dispersion of PI@BT nanofillers and the improved interfacial interactions between nanofillers and polymer matrix. These results provide useful information for the structural design of high-temperature dielectric materials.

Microstructure and Microwave Dielectric Properties of BaTi4O9 Ceramics Derived from a Sol-Gel Precursor

2011 ◽  
Vol 326 ◽  
pp. 127-130
Author(s):  
Xian Li Huang ◽  
Fu Ping Wang ◽  
Ying Song
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Sol Gel ◽  
Microwave Dielectric Properties ◽  
Sintering Process ◽  
Temperature Coefficients ◽  
Microwave Dielectric ◽  
Ceramic Samples ◽  
Quality Factor Q

In the present work, the microstructure and microwave dielectric properties of BaTi4O9 ceramics derived from a sol-gel precursor were presented. Density measuring results demonstrated that the largest densities of ceramic sample about 96.7% could be reached by virtue of a cool iso-static press and a sintering process at at 1300 °C for 6 hours. The dielectric constant (εr), quality factor (Q×f) and the temperature coefficients (τf) of the BaTi4O9 ceramic samples were 36.65, 28000 GHz, +20.2 ppm/°C, respectively. XRD, SEM and XPS were used to characterize the microstructure of the ceramics samples. Substantial Ti3+ was proposed to be the cause of dielectric loss.

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