Electromagnetic Properties of Concrete and Their Significance in Nondestructive Testing

1997 ◽  
Vol 1574 (1) ◽  
pp. 10-17 ◽  
Author(s):  
Oral Buyukozturk
Keyword(s):  
Dielectric Constant ◽  
Nondestructive Testing ◽  
Loss Factor ◽  
Electromagnetic Waves ◽  
Imaging Techniques ◽  
Electromagnetic Property ◽  
Microwave Frequency ◽  
Electromagnetic Properties ◽  
Frequency Variation ◽  
Hardened Concrete

Electromagnetic properties of hardened concrete specimens are measured over a microwave frequency range from 0.1 to 20 GHz. The experimentally obtained values provide information about the behavior of concrete and its interaction with electromagnetic waves. In addition to the frequency variation, the effect of different moisture contents on the electromagnetic properties is studied. Properties of mortar specimens and constituents of concrete, that is, coarse aggregates, sand, and cement, are also measured. An open-ended coaxial probe method is used for the measurement of real and imaginary parts of complex permittivity of concrete. The physical significance of the measured data in nondestructive testing, including penetration depth and detectability, is discussed. The results of electromagnetic property measurements indicate that the dielectric constant of dry concrete appears to be frequency independent over the range from 0.1 to 20 GHz, whereas the loss factor increases over that range. The moisture content of concrete significantly affects the dielectric constant and loss factor. The quantitative results obtained from this research will serve as a basis in applying wideband microwave imaging techniques for nondestructive testing of concrete using radar. The results can also be used for selecting the optimum combinations of radar measurement parameters for better detection.

scholarly journals The Effects of SLS on Structural and Complex Permittivity of SLS-HDPE Composites

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Abubakar Dantani Meli ◽  
Zulkifly Abbas ◽  
Mohd Hafiz Mohd Zaid ◽  
Nor Azowa Ibrahim
Keyword(s):  
Dielectric Constant ◽  
Complex Permittivity ◽  
Loss Factor ◽  
Microwave Frequency ◽  
Soda Lime ◽  
Physical Structure ◽  
Host Matrix ◽  
Lower Dielectric Constant ◽  
Absorbing Material ◽  
Diffraction Patterns

RS-4050 is a rigid epoxy based magnetic castable microwave absorbing material; it has been used in many areas of waveguide application as a microwave waveguide terminations and dummy loads. In recent years, there is a demand for composites material with lower dielectric constant higher loss factor for microwave application. This research, the effect of soda lime silica (SLS) on structural and complex permittivity of soda lime silica-high density polyethylene (SLS-HDPE) composites was conducted in order to explore the possibility of substituting RS-4050 with SLS-HDPE composites as a microwave waveguide terminations and dummy loads. Elemental weight composition of the SLS glass powder and HDPE was identified through scaling of different percentage of SLS and HDPE. X-ray diffraction (XRD) was used to investigate the crystallinity behavior of SLS-HDPE composites. The proposed SLS-HDPE composites material was studied at frequencies 8 to 12 GHz. The study was conducted using waveguide Agilent N5230A PNA technique. The effect of microwave frequency on complex permittivity properties for SLS-HDPE composites of different percentages of SLS and HDPE (10% SLS-90% HDPE, 20% SLS-80% HDPE, 30% SLS-70% HDPE, 40% SLS-60% HDPE, and 50% SLS-50% HDPE) were investigated. Results showed the diffraction patterns reveal good amorphous quality with a genuinely properties structure. The microwave frequency and composites percentages significantly influenced the complex permittivity (real and imaginary) properties of the composites. Moreover, the complex permittivity increased as the percentage of SLS filler increased in the host matrix HDPE as a result of increased in composite density due to less volume being occupied by the filler as the percentage increased. The complex permittivity of the smallest and largest percentages of SLS (10% and 50%) was (2.67-j0.05) and (3.45-j0.35), respectively. The study revealed that the best sample for waveguide application as microwave terminator is 50% SLS as it has the highest dielectric constant, highest loss factor, and highest loss tangent as compared to 10% SLS to 40% SLS. Also 50% SLS has the highest absorption properties as compare to 10% SLS, 20% SLS, 30% SLS, or 40% SLS. The XRD physical structure of the SLS-HDPE composites revealed the absorption characteristics of different percentages of the materials. The SLS-HDPE composites can be applied in the area of waveguide as a microwave waveguide terminations and dummy loads.

scholarly journals The Analysis of Dielectric Constant, Loss Factor and Q-Factor of Selected Fruits at Microwave Frequency Range

2020 ◽  
pp. 57-66
Author(s):  
J. T. Ikyumbur ◽  
A. A. McAsule ◽  
N. S. Akiiga ◽  
Z. E. Andrawus ◽  
S. T. Kungur
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Loss Factor ◽  
Microwave Frequency ◽  
Dielectric Loss Factor ◽  
Q Factor ◽  
Frequency Range ◽  
Temperature Changes ◽  
Problem Solving Environment ◽  
Lower Frequencies

The dielectric constant, dielectric loss factor and Q-Factor of orange, red and green apples were studied at Microwave frequency range. An algorithm was written using the Debye equations and the interactive problem-solving environment of Maple-18 was used to generate results for the dielectric constant, loss factor and quality factor. The variation in the dielectric constant, loss factor and Q-factor as both frequency and temperature changes respectively within   and  range were shown graphically. The dielectric constant of all the fruits were higher at lower frequencies, it then decreases continuously as frequency increases. On the other hand, the loss factor of this fruits were small at lower frequencies but increased to its peak before decreasing continuously for all temperatures. Interestingly, the fruits’ Q-Factor were higher at lower frequencies and temperatures but decreases rapidly as the frequency increases. The contribution of the space charge, orientation, ionic and electronic polarizations to the dielectric constant, dielectric loss factor and Q-Factor of these fruits at lower frequency and higher frequency were discussed. The effect of the excess sugar and water content on the dielectric constant, loss factor and Q-Factor attributed to the appearance of vibrational peaks was also discussed. This work hereby provides a guidance in developing new microwave processes.

Study on the Dielectric Properties of Biomass Material of Tobacco Stems

2013 ◽  
Vol 634-638 ◽  
pp. 2570-2578 ◽  
Author(s):  
Wen Hua Zi ◽  
Xiao Long Zhang ◽  
Lan Wang ◽  
Jin Hui Peng ◽  
Lin Chen
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Moisture Content ◽  
Loss Factor ◽  
Microwave Frequency ◽  
Dielectric Loss Factor ◽  
Dipolar Relaxation ◽  
Genetic Characteristics ◽  
Position Location

An Agilent E4980A precision the LCR meter was used to estimate the effect of frequency, moisture content, position, location and variety on dielectric properties for biomass material of tobacco stems at microwave frequency of 2MHz. The dielectric properties of tobacco stems were significantly affected by frequency and moisture content. Both dielectric constant and dielectric loss factor rapidly declined first and then slowed with increasing frequency at lower moisture content. Increasing the moisture content, dielectric constant increased with the increasing frequency by orders of magnitude, while dielectric loss factor increased first and then decreased with dielectric relaxation emerging, where the dipolar relaxation frequency and the max of the dielectric loss factor also increased. Dielectric properties of the biomass material of tobacco stem were also affected by position, location and variety to some degree. The dielectric properties variation of K326 and Yun 87 was similar to each other which reflected their same genetic characteristics. At the frequency of 2MHz, dielectric constant and dielectric loss factor were mainly at 50-100 and 0.005-0.020, respectively.

Ground Penetrating Radar Algorithm to Sense the Depth of Blood Clot in Microwave Head Imaging

2022 ◽  
Vol 18 ◽  
Author(s):  
Lalitha Kandasamy ◽  
Manjula J.
Keyword(s):  
Electromagnetic Waves ◽  
Imaging Modality ◽  
Imaging Techniques ◽  
Blood Clot ◽  
Microwave Frequency ◽  
Biological Tissues ◽  
Computationally Efficient ◽  
Brain Stroke ◽  
Ground Penetrating ◽  
3D Em

Background: Microwave imaging is one of the emerging non-invasive portable imaging techniques, which uses nonionized radiations to take a detailed view of biological tissues in the microwave frequency range. Brain stroke is an emergency caused by the interruption of the blood supply into parts of brain, leading to the loss of millions of brain cells. Imaging plays a major role in stroke diagnosis for prompt treatment. Objective: This work proposes a computationally efficient algorithm called the GPR algorithm to locate the blood clot with a size of 10 mm in microwave images. Methods: The electromagnetic waves are radiated, and backscattered reflections are received by Antipodal Vivaldi antenna with the parasitic patch (48 mm*21 mm). The received signals are converted to a planar 2D image, and the depth of the blood clot is identified from the B-scan image. The novelty of this work lies in applying the GPR algorithm for the accurate positioning of a blood clot in a multilayered head tissue. Results: The proposed system is effectively demonstrated using a 3D EM simulator and simulated results are verified in a Vector network analyzer (E8363B) with an experimental setup. Conclusion: This an alternative safe imaging modality compared to present imaging systems(CT and MRI)

scholarly journals Measurement and Analysis of Dielectric Properties of Agricultural By-product Powders in Microwave Frequency Range

2019 ◽  
Vol 78 ◽  
pp. 02012
Author(s):  
Runeng Zhong ◽  
Tai Xiang ◽  
Qinhong Zheng ◽  
Bo Xu
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Moisture Content ◽  
Loss Factor ◽  
Microwave Frequency ◽  
Powder Materials ◽  
Microwave Assisted ◽  
Measurement And Analysis ◽  
By Products

Dielectric properties play an important role in the microwave-assisted application of nonmagnetic agriculture-related media. In this paper, the practical requirements for the lack of quantitative data on the dielectric properties of agricultural media in microwave-assisted applications are obtained. The dielectric properties data of four kinds of agricultural by-products powder (Potato powder, Pseudo -ginseng Powder, Gastrodia elata powder, Dendrobium chrysotoxum Lindl powder) under microwave frequency were measured, and related factors were analyzed. The results show that the uncalibrated coaxial transmission reflection method can be used to measure and analyse the dielectric properties of high frequency bands of powder materials. Dielectric constant (ε ′) and Dielectric loss factor (ε '') of agricultural by-products at room temperature have a relationship between microwave frequency and moisture content. It is a dependent and the mathematical relation is satisfied. The influence of microwave frequency and moisture content on the dielectric properties is as follows: lows: ε′>ε′′>tanδ. Under the conditions of civil microwave frequency (2.45GHz) and moisture content (2% ~ 25%), the dielectric constant and the dielectric loss factor of different kinds of agricultural by-products powder are in the range of 3.5 ~ 9 and 0.1 ~ 3.2 respectively. The results provide data basis for microwave processing and quality monitoring of agricultural by-products powder. The technical method is suitable for the measurement and analysis of the dielectric properties of powder materials.

Development of a Capacitor Probe to Detect Subsurface Deterioration in Concrete

1997 ◽  
Vol 503 ◽  
Author(s):  
B. K. Diefenderfer ◽  
I. L. Al-Qadi ◽  
J. J. Yoho ◽  
S. M. Riad ◽  
A. Loulizi
Keyword(s):  
Dielectric Constant ◽  
Portland Cement ◽  
Electromagnetic Waves ◽  
Low Cost ◽  
Complex Dielectric Constant ◽  
Life Cycle Costs ◽  
Parallel Plates ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Set Up

ABSTRACTPortland cement concrete (PCC) structures deteriorate with age and need to be maintained or replaced. Early detection of deterioration in PCC (e.g., alkali-silica reaction, freeze/thaw damage, or chloride presence) can lead to significant reductions in maintenance costs. However, it is often too late to perform low-cost preventative maintenance by the time deterioration becomes evident. By developing techniques that would enable civil engineers to evaluate PCC structures and detect deterioration at early stages (without causing further damage), optimization of life-cycle costs of the constructed facility and minimization of disturbance to the facility users can be achieved.Nondestructive evaluation (NDE) methods are potentially one of the most useful techniques ever developed for assessing constructed facilities. They are noninvasive and can be performed rapidly. Portland cement concrete can be nondestructively evaluated by electrically characterizing its complex dielectric constant. The real part of the dielectric constant depicts the velocity of electromagnetic waves in PCC. The imaginary part, termed the “loss factor,” describes the conductivity of PCC and the attenuation of electromagnetic waves.Dielectric properties of PCC have been investigated in a laboratory setting using a parallel plate capacitor operating in the frequency range of 0.1 to 40.1MIHz. This capacitor set-up consists of two horizontal-parallel plates with an adjustable separation for insertion of a dielectric specimen (PCC). While useful in research, this approach is not practical for field implementation. A new capacitor probe has been developed which consists of two plates, located within the same horizontal plane, for placement upon the specimen to be tested. Preliminary results show that this technique is feasible and results are promising; further testing and evaluation is currently underway.

scholarly journals Preparation and electromagnetic properties characterization of reduced graphene oxide/strontium hexaferrite nanocomposites

2020 ◽  
Vol 9 (1) ◽  
pp. 105-114 ◽  
Author(s):  
Shumin Du ◽  
Huaiyin Chen ◽  
Ruoyu Hong
Keyword(s):  
Electromagnetic Wave ◽  
Environmental Pollution ◽  
Electromagnetic Interference ◽  
Electromagnetic Waves ◽  
Rapid Development ◽  
Living Environment ◽  
World Health ◽  
Electromagnetic Properties ◽  
Strontium Hexaferrite ◽  
Wave Radiation

AbstractWith the rapid development of electronics and information technology, electronics and electrical equipment have been widely used in our daily lives. The living environment is full of electromagnetic waves of various frequencies and energy. Electromagnetic wave radiation has evolved into a new type of environmental pollution that has been listed by the WHO (World Health Organization) as the fourth largest source of environmental pollution after water, atmosphere, and noise. Studies have shown that when electromagnetic wave radiation is too much, it can cause neurological disorders. And electromagnetic interference will cause the abnormal operation of medical equipment, precision instruments and other equipment, and therefore cause incalculable consequences. Therefore, electromagnetic protection has become a hot issue of concern to the social and scientific circles.

A study on the electromagnetic properties of graphite/bismuth/bismuth oxide-coated composites

2021 ◽  
pp. 004051752199434
Author(s):  
Yuanjun Liu ◽  
Yanfeng Yang
Keyword(s):  
Mechanical Property ◽  
Dielectric Constant ◽  
Bismuth Oxide ◽  
Control Variable ◽  
Single Layer ◽  
Polarization Property ◽  
Electromagnetic Properties ◽  
Shielding Effectiveness ◽  
Absorbing Property ◽  
Layer Coating

Coating is a commonly used process for the preparation of protective textiles. In this study, the absorbing coated composite material was prepared by a coating process, using plain weave polyester/cotton fabric as the base fabric, PU-2540 polyurethane as the binder, and graphite, bismuth and bismuth oxide as the functional particles. The effects of the content of functional particles and the ratio of functional particles on the dielectric constant, reflection loss, shielding effectiveness, and tensile strength of the single-layer coating composites were studied using the control variable method. The results showed that when the frequency was 1–1000 MHz, the real and imaginary parts of the dielectric constant, the tangential value of the loss angle, and the tensile value increased with the increase of the coating content, and the polarization, loss and attenuation property, and mechanical property of the electromagnetic wave were enhanced. When graphite, bismuth, and bismuth oxide was mixed at the ratio of 9:0:0 in weight, the polarization property was the best. When mixed at the ratio of 6:1:2 in weight, the loss performance and attenuation ability were the best. When mixed at the ratio of 6:3:0 in weight, the absorbing property and mechanical property were the best. When mixed at the ratio of 6:2:1 in weight, the shielding property was the best.

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