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Tailings management using TDR technology
Published in A.A. Balkema, Tailings and Mine Waste 2000, 2022
K.M. O’Connor, D.A. Poulter, D. Znidarcic
Time Domain Reflectometry (TDR) was developed by the power and telecommunications industries to locate faults in cables. A cable tester launches a voltage pulse into a coaxial cable, parallel pair wire or twisted pair wire. Wherever there is a change in electrical properties, due to cable damage or water ingress, a portion of the voltage is reflected back to the tester which displays the ratio of reflected to transmitted voltage as a reflection coefficient. The waveform shape is a function of the type and magnitude of cable damage. The travel time is converted to distance by knowing the propagation velocity which is a property of the cable or wire. Consequently, it is possible to display all reflections and identify the type and location of cable damage.
Time and Frequency Domain Responses
Published in Wai-Kai Chen, Feedback, Nonlinear, and Distributed Circuits, 2018
Time-domain reflectometry (TDR) is used to characterize interconnections in the time domain. The setup essentially Consists of a time domain step generator and a digital sampling oscilloscope (Figure 17.1) [1]. The generator produces a positive-going step signal with a well-defined rise time. The step is applied to the device under test. The reflected and the transmitted signals are shown on the oscilloscope. Measuring the reflected signal is Called TDR; the transmitted signal is measured using the time-domain transmission (TDT) option.
Surface mining
Published in A.J.S. (Sam) Spearing, Liqiang Ma, Cong-An Ma, Mine Design, Planning and Sustainable Exploitation in the Digital Age, 2023
A.J.S. (Sam) Spearing, Liqiang Ma, Cong-An Ma
Measuring the pit wall stability during mining is very important and has become a very useful tool in determining potential instability, and it generally permits men and equipment to be removed from harm's way safely. The recent development of cost-effective and sensitive instruments has made this process more accurate, repeatable and reliable. For effective monitoring, a movement of a cm or less should be detected to give a maximum time to react. Monitoring methods that can be used include: LiDAR Scanning stands for Light Detection and Ranging and uses a laser measuring the reflection off surfaces to determine their precise position but relative and not global. The accuracy is currently typically 1–3 cm.Global Positioning Systems use satellites and radio navigation techniques to locate surfaces, etc. using at least four “line of sight” satellites to locate the surface or point. The accuracy is typically in the range of 1m so has limited value for accurate openpit stability monitoring currently.Slope Stability Radar Scanning uses radio waves to determine the position of objects or surfaces. The most modern systems have accuracies in a mm or less (e.g., the IBIS System).Time Domain Reflectometry is a measurement technique used to determine the characteristics and disruption along electrical lines by observing reflected waveforms. It can be used with coaxial cables to determine failure and shear planes. It is not a very cheap or versatile method as it can only determine movement across a local cable often in a borehole. It is, however, able to determine very small movements.
Real-time remote energy consumption location for power management application
Published in Advances in Building Energy Research, 2021
Sam Moayedi, Hamed Nabizadeh Rafsanjani, Subhaditya Shom, Mahmoud Alahmad, Changbum R. Ahn
The basic concept of STDR is described using the Time Domain Reflectometry (TDR) method. Time Domain Reflectometry (TDR) is based on the reflective property of waveforms on a conducting medium. The principle of TDR is similar to the radar. TDR technique is used for locating short-circuits, faults or damage and discontinues or impedance mismatches on wires for electrical and communication systems (Iskander, 2000). In this method, a pulse signal injects to the wire and it reflects back when it reaches the end of the wire or when there is an impedance changes. The wave propagation along the transmission line depends on the velocity of propagation (VOP) or velocity factor (VF) of the medium. VF is the speed at which a wave travels through the wire, relative to the speed of light (Ulaby, Michielssen, & Ravaioli, 2010). Using the VOP of the desired wire, and measuring the signal’s time for travelling to the end and reflecting back, length of the wire or distance to the impedance mismatch can be determined.