An Innovative Use of TDR Probes: First Numerical Validations with a Coaxial Cable

2018 ◽  
Vol 23 (4) ◽  
pp. 437-442
Author(s):  
Raffaele Persico ◽  
Iman Farhat ◽  
Lourdes Farrugia ◽  
Sebastiano D'Amico ◽  
Charles Sammut
Keyword(s):  
Magnetic Properties ◽  
Transmission Line ◽  
Time Domain ◽  
Numerical Data ◽  
Time Domain Reflectometry ◽  
Coaxial Cable ◽  
Transmission Line Model ◽  
Properties Of Materials

In this paper we propose a study regarding some possibilities that can be offered by a time domain reflectometry (TDR) probe in retrieving both dielectric and magnetic properties of materials. This technique can be of interest for several applications, among which the characterization of soil in some situations. In particular, here we propose an extension of the paper “Retrieving electric and magnetic propetries of the soil in situ: New possibilities”, presented at the IWAGPR, held in Edinburgh in 2017, and as a new contribution we will validate a transmission line model with numerical data simulated by the CST code.

scholarly journals Time domain reflectometry model: analysis and characterization of a chafing defect in a coaxial cable

2018 ◽  
Vol 83 (3) ◽  
pp. 30601 ◽  
Author(s):  
Abelin Kameni ◽  
Florent Loete ◽  
Lionel Pichon
Keyword(s):  
Time Domain ◽  
Time Domain Reflectometry ◽  
Coaxial Cable ◽  
Network Analyzer ◽  
3D Numerical Modeling ◽  
Numerical Studies ◽  
A Chain ◽  
The Time Domain ◽  
The Impact

This paper presents experimental and numerical studies of a chafing soft defect realized by partially milling coaxial cables. The approach is based on the time domain reflectometry technique. The numerical model consists in solving Maxwell’s equations while an incident Gaussian pulse is injected on the faulty line. The experimental time domain measurements are performed with a vector network analyzer. To get the experimental results comparable to the numerical ones, a process to denoise the measured impulse responses is proposed. The reflection coefficients obtained are compared to those given by a classical approach based on a chain matrix model to show the impact of 3D numerical modeling in studying soft faults.

scholarly journals Detection and Characterization of Multiple Discontinuities in Cables with Time-Domain Reflectometry and Convolutional Neural Networks

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 8032
Author(s):  
Marco Scarpetta ◽  
Maurizio Spadavecchia ◽  
Francesco Adamo ◽  
Mattia Alessandro Ragolia ◽  
Nicola Giaquinto
Keyword(s):  
Neural Network ◽  
Transmission Line ◽  
Time Domain ◽  
Mean Squared Error ◽  
Experimental Tests ◽  
Time Domain Reflectometry ◽  
The Neural Network ◽  
Using Data ◽  
Impedance Discontinuity

In this paper, a convolutional neural network for the detection and characterization of impedance discontinuity points in cables is presented. The neural network analyzes time-domain reflectometry signals and produces a set of estimated discontinuity points, each of them characterized by a class describing the type of discontinuity, a position, and a value quantifying the entity of the impedance discontinuity. The neural network was trained using a great number of simulated signals, obtained with a transmission line simulator. The transmission line model used in simulations was calibrated using data obtained from stepped-frequency waveform reflectometry measurements, following a novel procedure presented in the paper. After the training process, the neural network model was tested on both simulated signals and measured signals, and its detection and accuracy performances were assessed. In experimental tests, where the discontinuity points were capacitive faults, the proposed method was able to correctly identify 100% of the discontinuity points, and to estimate their position and entity with a root-mean-squared error of 13 cm and 14 pF, respectively.

Characterization of contact resistance of low-value resistor by transmission line model (TLM) method

2002 ◽  
Vol 85 (3) ◽  
pp. 16-22
Author(s):  
Kiichi Kamimura ◽  
Shinsuke Okada ◽  
Masato Nakao ◽  
Yoshiharu Onuma ◽  
Shozo Yamashita
Keyword(s):  
Contact Resistance ◽  
Transmission Line ◽  
Transmission Line Model ◽  
Line Model ◽  
Tlm Method

Measuring transient solute transport through the vadoze zone using time domain reflectometry

Soil Research ◽  
2001 ◽  
Vol 39 (6) ◽  
pp. 1359 ◽  
Author(s):  
I. Vogeler ◽  
S. Green ◽  
A. Nadler ◽  
C. Duwig
Keyword(s):  
Electrical Conductivity ◽  
Solute Transport ◽  
Time Domain ◽  
Deterministic Model ◽  
Soil Surface ◽  
Time Domain Reflectometry ◽  
Richards Equation ◽  
Electrical Conductivities ◽  
Destructive Measurement

Time domain reflectometry (TDR) was used to monitor the transport of conservative tracers in the field under transient water flow in a controlled experiment under a kiwifruit vine. A mixed pulse of chloride and bromide was applied to the soil surface of a 16 m2 plot that had been isolated from the surrounding orchard soil. The movement of this solute pulse was monitored by TDR. A total of 63 TDR probes were installed into the plot for daily measurements of both the volumetric water content (θ) and the bulk soil electrical conductivity (σa). These TDR-measured σa were converted into pore water electrical conductivities (σw) and solute concentrations using various θ–σa–σw relationships that were established in the laboratory on repacked soil. The depth-wise field TDR measurements were compared with destructive measurement of the solute concentrations at the end of the experiment. These results were also compared with predictions using a deterministic model of water and solute transport based on Richards’ equation, and the convection–dispersion equation. TDR was found to give a good indication of the shape of the solute profile with depth, but the concentration of solute was under- or over-estimated by up to 50%, depending on the θ–σa–σw relationships used. Thus TDR can be used to monitor in situ transport of contaminants. However, only rough estimates of the electrical conductivity of the soil solution can so far be obtained by TDR.

scholarly journals Multidisciplinary Characterization of Chlorinated Solvents Contamination and In-Situ Remediation with the Use of the Direct Current Resistivity and Time-Domain Induced Polarization Tomography

Geosciences ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 487 ◽  
Author(s):  
Aristeidis Nivorlis ◽  
Torleif Dahlin ◽  
Matteo Rossi ◽  
Nikolas Höglund ◽  
Charlotte Sparrenbom
Keyword(s):  
Direct Current ◽  
Time Domain ◽  
Chlorinated Solvents ◽  
Induced Polarization ◽  
Contaminated Sites ◽  
In Situ Remediation ◽  
Polarization Tomography ◽  
Refraction Tomography

Soil contamination is a widespread problem and action needs to be taken in order to prevent damage to the groundwater and the life around the contaminated sites. In Sweden, it is estimated that more than 80,000 sites are potentially contaminated, and therefore, there is a demand for investigations and further treatment of the soil. In this paper, we present the results from a methodology applied in a site contaminated with chlorinated solvents, for characterization of the contamination in order to plan the remediation and to follow-up the initial step of in-situ remediation in an efficient way. We utilized the results from three different methods; membrane interface probe for direct measurement of the contaminant concentrations; seismic refraction tomography for investigating the depth to the bedrock interface; and direct current resistivity and time-domain induced polarization tomography to acquire a high-resolution imaging of the electrical properties of the subsurface. The results indicate that our methodology is very promising in terms of site characterization, and furthermore, has great potential for real-time geophysical monitoring of contaminated sites in the future.

Sign in / Sign up

Export Citation Format

Share Document