Effect of moisture content on dielectric properties of banana leaves and peels in frequency range of 1–20 GHz

Frequenz ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Soumya Sundar Pattanayak ◽  
Soumen Biswas

Abstract The quality of agricultural products can be remotely sensed and enhanced by determining the dielectric properties. This paper studies the dielectric properties of banana leaf and banana peel over the frequency range 1–20 GHz using the open-ended coaxial probe (OCP) method. A new curve fitting model is proposed to characterize the dielectric properties of banana leaf and banana peel. The different moisture content (MC) levels are considered for both banana leaf and banana peel samples and, their dielectric properties are characterized. Further, the banana leaf and banana peel’s measurement data are compared with the data obtained using the proposed model. In addition, Root Mean Square Error (RMSE) and R-squared (R 2) are calculated to validate the performance of the proposed model. In case of banana leaf at 68.26% MC, the dielectric constant achieves the value of R 2 and RMSE of 0.98 and 0.0648, respectively. Similarly, dielectric loss achieves the value of R 2 and RMSE of 0.88 and 0.0795, respectively. Further, for banana peel at 80.89% MC, the dielectric constant achieves the value of R 2 and RMSE of 0.99 and 0.2989, respectively. Similarly, dielectric loss achieves the value of R 2 and RMSE of 0.96 and 0.6132, respectively.

Author(s):  
Vishal Singh Chandel ◽  
Atiq UR Rahmanm ◽  
J. P. Shukla ◽  
Rajiv Manohar ◽  
Mohd. Shafi Khan

Effect of fungicides' (thiram, captan, carbendazim, bagalol) treatment on dielectric constant and dielectric loss of a vegetable seed, namely the brinjal at given moisture content and bulk density was examined using Hewlett-Packard (HP-4194A) impedance/gain phase analyzer over the frequency range of 0.01 to 10 MHz and temperature range of 30-450C. Julabo (temperature controller, F-25, Germany) was used for keeping the temperature of seeds constant. Study showed that fungicide treatment cast considerable change in dielectric parameters namely the dielectric constant and dielectric loss.


2014 ◽  
Vol 66 (1) ◽  
pp. 17-28 ◽  
Author(s):  
Mohd. Shafi Khan ◽  
Vishal Singh Chandel ◽  
Rajiv Manohar ◽  
Jagdeesh Prasad Shukla

Abstract The present paper studied the dielectric constant, dielectric loss, and ac conductivity of fenugreek seed, a medicinal seed (Trigonella foenum graecum), within the frequency range of 10 kHz and 10 MHz and the temperature range of 30°C and 50°C. Impedance gain/phase analyser (HP 4194 A) was used to measure the dielectric constant and the dielectric loss and Julabo (temperature controller, F-25, Germany) was used for keeping the temperature of fenugreek seeds constant. It was found that the dielectric constant and the dielectric loss decrease with the increase in the frequency while the same increase with the increase in temperature and moisture content. The ac conductivity increased with the increase in frequency, moisture and temperature.


2021 ◽  
Vol 64 (4) ◽  
pp. 1373-1379
Author(s):  
Samir Trabelsi

HighlightsMoisture and water activity were determined nondestructively and in real time from measurement of dielectric properties.Moisture and water activity calibration equations were established in terms of the dielectric properties.Situations in which bulk density was known or unknown were considered.SEC ranged from 0.41% to 0.68% for moisture and from 0.02 to 0.04 for water activity.Abstract. A method for rapid and nondestructive determination of moisture content and water activity of granular and particulate materials was developed. The method relies on measurement of the dielectric constant and dielectric loss factor at a single microwave frequency. For the purpose of illustration, the method was applied to predicting the moisture content and water activity of almond kernels. A free-space transmission technique was used for accurate measurement of the dielectric properties. Samples of Bute Padre almond kernels with moisture content ranging from 4.8% to 16.5%, wet basis (w.b.), and water activity ranging from 0.50 to 0.93 were loaded into a Styrofoam sample holder and placed between two horn-lens antennas connected to a vector network analyzer. The dielectric properties were calculated from measurement of the attenuation and phase shift at 8 GHz and 25°C. The dielectric properties increased linearly with moisture content, while they showed an exponential increase with water activity. Situations in which the bulk density was known and unknown were considered. Linear and exponential growth regressions provided equations correlating the dielectric properties with moisture content and water activity with coefficients of determination (r2) higher than 0.96. Analytical expressions of moisture content and water activity in terms of the dielectric properties measured at 8 GHz and 25°C are provided. The standard error of calibration (SEC) was calculated for each calibration equation. Results show that moisture content can be predicted with SECs ranging from 0.41% to 0.68% (w.b.) and water activity with SECs ranging from 0.02 to 0.04 for almond kernel samples with water activity ranging from 0.5 to 0.9 and moisture contents ranging from 4.8% to 16.5% (w.b.). Keywords: Bulk density, Dielectric constant, Dielectric loss factor, Free-space measurements, Loss tangent, Microwave frequencies, Moisture content, Water activity.


Author(s):  
K.Ch. Varada Rajulu ◽  
B.N. Mohanty

This study presents the dielectric and conductivity properties as function of temperature and frequency of wood based composites. These properties were measured by an open-ended coaxial probe at frequency range between 100 kHz to 100MHz, temperature from 30OC to 200OC which is fully computer interfaced. It has been observed that dielectric constant (ε') and dielectric loss factor (ε") increase with increasing temperature and decrease with increasing frequency. At low temperature region, the conductivity depends significantly on the frequency. However, with the increase in temperature dielectric relaxation takes place and the dependency of the conductivity on frequency get reduced. The patterns of variation were established for the studied specimens and discrepancies were discussed. The study of dielectric properties will help in improving the drying, heating and gluing processes of wood and wood based products.


2012 ◽  
Vol 16 (07n08) ◽  
pp. 826-832 ◽  
Author(s):  
Mevlüde Canlıca ◽  
Ahmet Altındal ◽  
Tebello Nyokong

The synthesis of ball-type dinuclear Zn(II) phthalocyanine containing four 4,4′-(9H-fluorene-9,9-diyl)diphenol substituents at the non-peripheral position is presented. The structure of the synthesized compound was characterized using elemental analyzes, and UV-vis, FT-IR,1H NMR and mass spectroscopies. The ΦFvalue was 0.16 and ΦTvalue was 0.72. The complex showed reasonably long triplet lifetimes with τT7210 μs in DMSO. The frequency and temperature dependence of the dielectric properties of ZnPc were also investigated in the frequency range of 40–105Hz and in the temperature range of 300–440 °K. It has been observed that both dielectric constant ε′ and dielectric loss ε″ decrease with the rise in frequency as they increase with the rise in temperature. The decrease in ε′ with increasing frequency is attributed to the fact that as the frequency increases, the polarizability contribution from orientation sources decreases and finally disappears.


2015 ◽  
Vol 1107 ◽  
pp. 38-44
Author(s):  
Wong Yick Jeng ◽  
Hassan Jumiah ◽  
Mansor Hashim

The CaTiO3samples were prepared by high-energy ball milling process followed by sintering process from 1040 to 1200°C. X-ray diffraction (XRD), microstructural analysis, and dielectric properties over a wide range of frequency varying from 0.01 Hz to 1 GHz at room temperature were investigated. The formation of a single phase CaTiO3with orthorhombic structure was achieved at 1120°C and above. From a morphological point of view, sintering temperature promoted grain growth. Dielectric properties in the frequency range 0.01 Hz - 1 MHz revealed a relaxation-type process. Interfacial phenomena were the possible physical mechanisms that gave rise to these relaxation-type plots. Extending the frequencies above ~1 MHz yielded a frequency-independent characteristic of dielectric constant (ε'). These turned out to the relatively small dielectric loss (tan δ) values. The origin of the dielectric responses in the frequency range 1 MHz - 1 GHz was attributed to the domination of dipolar polarization. The grain size effect in sintered CaTiO3samples was prominent, notably in dielectric responses above ~1 MHz. Increase in sintering temperature remarkably led to an enhancement in dielectric constant values and reduction in dielectric loss values. Therefore, a significant correlation existed between microstructural features and dielectric properties.


2009 ◽  
Vol 66 ◽  
pp. 234-237 ◽  
Author(s):  
Hao Yan ◽  
Zhi Xiong Huang ◽  
Yan Bing Wang

The Magnesium Niobate-Lead Titanate (PMN) / conductive carbon black (CB)/ chlorobutyl rubber(CIIR) composites were prepared by blending-vulcanization method, and the dielectric properties were studied. The results showed that the dielectric constant and dielectric loss of composites increased nonlinearly when increasing the content of PMN or CB. From the curve of dielectric constant vs frequency, it is obtained that in the frequency range from 103 to 106 Hz, the dielectric constant of PMN/CB/CIIR composites decreased with the frequency increasing and the dielectric constants are more stable under high frequency.


Clay Minerals ◽  
2014 ◽  
Vol 49 (4) ◽  
pp. 551-558
Author(s):  
S. Gümüştas ◽  
K. Köseoğlu ◽  
E. E. Yalçinkaya ◽  
M. Balcan

AbstractThe purpose of this paper is to determine the effect of NaF and firing temperature on the dielectric properties (dielectric constant and dielectric loss) of talc, which is used in the electrical and electronic industries as a circuit element. A detailed characterization of the samples was made by XRD, FTIR, SEM and TG-DTG methods. Dielectric measurements were performed in the frequency range from 1 MHz to 80 MHz at room temperature. The dielectric constant value increased with an increase in firing temperature due to the removal of polarizable compounds from the talc structure. The higher dielectric constant values were obtained by addition of NaF. The dielectric loss of NaF doped talc decreased with the increase of firing temperature and increased with the increase of the amount of NaF.


Author(s):  
JAYASHREE BIJWE ◽  
NEELAM PHOUGAT

Monomeric and polymeric iron phthalocyanine compounds were synthesized and their dielectric properties were measured in the frequency range from 100 Hz to 10 MHz between 25 and 200 °C. The dielectric constant and dielectric loss showed strong frequency and temperature dependences. Interestingly, large dielectric constants were observed around 100 °C for both monomers and polymers. A dielectric constant as high as 5000 at 110 Hz was observed for the iron phthalocyanine polymer. The origin of the large dielectric constant in metallophthalocyanines is discussed.


2008 ◽  
Vol 55-57 ◽  
pp. 105-108 ◽  
Author(s):  
Nidchakarn Krueson ◽  
H. Manuspiya ◽  
Pitak Laoratanakul ◽  
H. Ishida

This research proposed a novel nano barium strontium titanate (BST) powder- polybenzoxazine composite as a new dielectric material. In this work, the dielectric properties of a surface-treated BST powder-polybenzoxazine composite were studied. The surface of the BST powders were modified by using three different chemicals: 3-aminopropyl-trimethoxysilane, benzoxazine monomer and phthalocyanine. The distribution of the BST powders in the polybenzoxazine matrix was observed by SEM. The dielectric constants of the composites with a function of frequency (1 kHz–10 MHz) were investigated. It was found that the composites with modified BST powders showed good distribution in the polybenzoxazine matrix, and the dielectric constants were also much enhanced than those with untreated BST powders. In comparisons among the three modification methods, the composite with the silane coupling modified BST powder showed significantly in dielectric constant improvement while the composite with the benzoxazine and phthalocyanine modified BST powders displayed lower dielectric loss due to the modified powder dispersed well in the polybenzoxazine matrix.


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