Investigating the dielectric properties of materials for making simulators of the moisture content of solid bodies

1980 ◽  
Vol 23 (3) ◽  
pp. 266-268
Author(s):  
A. S. Zaporozhets ◽  
A. A. Ichitovkin ◽  
A. M. Men'shikov ◽  
Yu. G. Podkin
Keyword(s):  
Dielectric Properties ◽  
Moisture Content ◽  
Properties Of Materials ◽  
Solid Bodies

scholarly journals Effects of Moisture, Temperature, and Salt Content on the Dielectric Properties of Pecan Kernels During Microwave and Radio Frequency Drying Processes

Foods ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 385 ◽  
Author(s):  
Zhang ◽  
Li ◽  
Cheng ◽  
Wang ◽  
Ding ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Moisture Content ◽  
Radio Frequency ◽  
Salt Content ◽  
Rf Heating ◽  
Dielectric Heating ◽  
Time Histories ◽  
Properties Of Materials ◽  
Content Range ◽  
Temperature Time

Dielectric properties of materials influence the interaction of electromagnetic fields with and are therefore important in designing effective dielectric heating processes. We investigated the dielectric properties (DPs) of pecan kernels between 10 and 3000 MHz using a Novocontrol broadband dielectric spectrometer in a temperature range of 5–65 °C and a moisture content range of 10–30% wet basis (wb) at three salt levels. The dielectric constant (ε′) and loss factor (ε′′) of the pecan kernels decreased significantly with increasing frequency in the radio frequency (RF) band, but gradually in the measured microwave (MW) band. The moisture content and temperature increase greatly contributed to the increase in the ε′ and ε′′ of samples, and ε′′ increased sharply with increasing salt strength. Quadratic polynomial models were established to simulate DPs as functions of temperature and moisture content at four frequencies (27, 40, 915, and 2450 MHz), with R2 > 0.94. The average penetration depth of pecan kernels in the RF band was greater than that in the MW band (238.17 ± 21.78 cm vs. 15.23 ± 7.36 cm; p < 0.01). Based on the measured DP data, the simulated and experimental temperature-time histories of pecan kernels at five moisture contents were compared within the 5 min RF heating period.

scholarly journals Moisture Measurement in Paper and Cardboard Packaging Waste Bales for Recycling

2021 ◽  
Vol 11 (10) ◽  
pp. 4586
Author(s):  
Ana Silveira ◽  
João Cardoso ◽  
Maria José Correia ◽  
Graça Martinho
Keyword(s):  
Quality Control ◽  
Dielectric Properties ◽  
Moisture Content ◽  
Reliable Method ◽  
Drying Method ◽  
Waste Streams ◽  
Oven Drying ◽  
Quality Issue ◽  
Commercial Device ◽  
Non Destructive

Moisture content is a quality issue raised by recycling plants in the acceptance of paper and cardboard coming from waste streams. The current way to measure this parameter is by the oven drying method, which is a slow and invasive process, costing time and resources for the recyclers to do this type of quality control. An alternative to such a measurement technique is the use of plate-form devices which indirectly measure the moisture content using the dielectric properties of water and paper. This study has tested this method and developed a representative equation for the use of devices with these properties in the Portuguese market. For that, 48 wastepaper and cardboard bales were tested with both the traditional (oven drying) method and a commercial device equipped with dielectric technology. An equation that fits the studied reality (R2 = 0.76) was achieved, and possible problems regarding the use of this device were tested. The results showed that this type of device could be used as a time- and cost-saving, non-destructive and reliable method in the quality control of wastepaper and cardboard bales.

Metrological guarantee of unity of measurements of the moisture content of solid bodies

1973 ◽  
Vol 16 (8) ◽  
pp. 1230-1232
Author(s):  
V. E. Melkumyan
Keyword(s):  
Moisture Content ◽  
Unity Of Measurements ◽  
Solid Bodies

Microwave Nondestructive Sensing of Moisture Content and Water Activity of Almonds

2021 ◽  
Vol 64 (4) ◽  
pp. 1373-1379
Author(s):  
Samir Trabelsi
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Moisture Content ◽  
Bulk Density ◽  
Water Activity ◽  
Free Space ◽  
Loss Factor ◽  
Dielectric Loss Factor ◽  
List Type

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.

Dielectric Properties of Flaxseeds as affected by Moisture Content and Bulk Density in the Radio Frequency Range

2006 ◽  
Vol 93 (2) ◽  
pp. 153-160 ◽  
Author(s):  
K. Sacilik ◽  
C. Tarimci ◽  
A. Colak
Keyword(s):  
Dielectric Properties ◽  
Moisture Content ◽  
Radio Frequency ◽  
Bulk Density ◽  
Frequency Range

scholarly journals Analysis of methods for measuring the dielectric properties of materials in the microwave range of wavelengths.

2021 ◽  
Author(s):  
D.G. Fomin ◽  
◽  
N.V. Dudarev ◽  
S.N. Darovskikh ◽  
◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Communication Systems ◽  
Electronic Devices ◽  
Microwave Range ◽  
Advantages And Disadvantages ◽  
Microwave Electronic ◽  
Functional Features ◽  
Properties Of Materials ◽  
Materials Used ◽  
Resonant Method

One of the modern trends in the development of communication systems, information and telecommunication systems, air traffic control systems, etc. is the transition and development of higher-frequency wavelength ranges. In this regard more and more stringent requirements (in terms of spectrum, out-of-band and spurious radio emission, and in the shape of the output signal) are imposed on radio engineering devices that transmit and receive microwave radio signals. As a result, the requirements for the design and functional features of microwave electronic devices are increasing. One of these requirements is to assess the degree of compliance with the required values of dielectric properties of materials used in the design of microwave electronic devices. This requirement is justified by the fact that the electrical parameters of such microwave devices as: strip filters, power dividers, printed antennas and others, directly depend on the dielectric properties of the materials used in their substrate designs. In this regard, three main methods have now emerged for assessing the dielectric properties of materials: the resonant method, the non-resonant method, and the free space method. Aim. The aim of this article is to carry out a comparative analysis of the known methods for measuring the dielectric properties of materials in the microwave range of wavelengths and devices for their implementation. Materials and methods. The authors of the article reviewed the scientific literature of domestic and foreign publications. Results. For each of the methods for measuring the dielectric properties of materials, their main idea, practical implementation, a mathematical model for processing experimental data and areas of application are given. The advantages and disadvantages for each of the methods for measuring the dielectric properties of materials are given too. Conclusion. The applicability of each of the considered methods depends on such factors as: the shape of the investigated dielectric material, its state of aggregation, the possibility of measuring amplitude or complex transmission and reflection coefficients, the presence of an anechoic chamber, etc.

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
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Moisture Content ◽  
Measurement Data ◽  
Banana Peel ◽  
Frequency Range ◽  
Proposed Model ◽  
Banana Leaves ◽  
Banana Leaf

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.

Dielectric Properties of Vegetables and Fruits as a Function of Temperature, Ash, and Moisture Content

2003 ◽  
Vol 68 (1) ◽  
pp. 234-239 ◽  
Author(s):  
O. Sipahioglu ◽  
S.A. Barringer
Keyword(s):  
Dielectric Properties ◽  
Moisture Content ◽  
Vegetables And Fruits
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