Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 56 for “"Time Domain Reflectometry"”.
-
Dynamic Strain Measurement Using Brillouin Optical Time-Domain Reflectometry
… along the optic fibre. The Brillouin optical time-domain reflectometry (BOTDR) has the advantages of single-end access and simple operation at the construction site, which makes it very popular in civil engineering applications. Furthermore, the demand of the dynamic sensing of strain …
-
Temperature corrected strain measurements using optical time domain reflectometry
… measured using Fresnel-backscatter based Optical Time Domain Reflectometry, and a method for combining the two measurements to obtain a measurement of mechanically-induced strain alone is developed. The background, theory and experimental results that demonstrate the feasibility of such a system …
-
High resolution optical time domain reflectometry and its applications
High resolution Optical Time Domain Reflectometry (OTDR) measurements have recently allowed spatial resolutions of less than one millimeter. These capabilities indicate that OTDR techniques may be suitable for non-conventional applications such as the determination of fiber strain. This thesis …
-
Time-Frequency Localisation of Distributed Brillouin Optical Time Domain Reflectometry
… (SHM) of strain changes induced during the lifetime of a structure. Among different DFOS systems, the Brillouin Optical Time Domain Reflectometry (BOTDR) takes the advantages of obtaining full frequency spectrum to provide strain and temperature information along the optic fibre. The key …
-
Time domain reflectometry (TDR) techniques for the design of distributed sensors
… of a working system. The system consists of time domain reflectometry (TDR) signal processing equipment and specially designed sensing cables. The TDR equipment sends a high-frequency electric pulse (in the gigahertz range) along the sensing cable. Any change in electric impedance along the …
-
The effects of moving electron density fluctuations on time domain reflectometry in plasmas
The effects of time-dependent electron density fluctuations on a synthesized time domain reflectometry response of a one-dimensional cold plasma sheath are considered. Numerical solutions of the Helmholtz wave equation, which describes the electric field of a normally incident plane wave in a …
-
An investigation into using optical amplifiers for enhancing Brillouin based optical time domain reflectometry
Distributed fibre sensors have been successfully demonstrated and used in various industries for performing continuous measurements of the physical parameters such as temperature and strain. However, the measurement range and the performance of such sensors are limited by the intrinsic attenuation …
-
Multi-defect localization and evaluation techniques for distribution cables based on time-domain reflectometry
… power cables is of great practical significance. Time Domain Reflectometry (TDR) is widely used for detecting and localizing cable defects. By injecting a pulse signal into the cable and analyzing the reflected signal, TDR enables the detection and localization of defects. However, due to limited …
-
Studies of the use of time domain reflectometry to determine moisture content in finite regions
This thesis addresses several questions related to the sensitivity of TDR to the determination of the moisture in laboratory experiments where the measurement is done noninvasively; Some tests were performed on moistened sand in a plastic box, treating the moisture content as the independent …
-
REAL TIME MONITORING OF VOLUMETRIC WATER CONTENT IN RECLAIMED MINE WASTE USING CONE PENETRATION - TIME DOMAIN REFLECTOMETRY
… through reclaimed mine waste using a new time domain reflectometry (TDR) component added to conventional geotechnical cone penetration testing (CPT). Time domain reflectometry measures the volumetric water content of a soil by characterizing the dielectric constant of the soil – a property …
-
Hydrogeophysical quantification of infiltration and recharge through soil-filled sinkholes using Time Domain Reflectometry and Electrical Resistivity Tomography
… in two soil-filled sinkholes. Access-tube time domain reflectometry (TDR) was used to derive one-dimensional (1-D) soil moisture profiles. During access-tube installation, 470 soil samples were obtained from depths between 0.3 and to 9.0 m and characterized both physically and chemically. …
-
Part One: The Quantitative Prediction and Analysis of Enthalpies for The Interaction of Gas Phase Ion-Ion, Gas Phase Ion-Molecule, and Molecule-Molecule Lewis Acid-Base Systems. Part Two: The Study of Intervalence Transfer in Mixed Valence Systems Using Time Domain Reflectometry
In Part One, the equation -(DELTA)H = e(,A)e(,B) + c(,A)c(,B) + t(,A)t(,B) where the subscripts A and B refer to acid and base correlates the enthalpy of Lewis acid-base adduct formation for molecule-molecule, gas phase ion-molecule, and gas phase ion-ion interactions. The parameters obtained are …
-
Measurement of electromagnetic signal velocities in saturated fine-grained soils
… are common in soil disciplines, often involving Time-Domain Reflectometry. However, Time-Domain Reflectometry measurements are of limited use where velocity is frequency dependent, such as in finegrained soils. Therefore, Quarter-Wavelength Analysis was developed for measurements of velocities in …
-
Design, fabrication and application of a dedicated thick-film hybrid time domain reflectometer
… for developing a dedicated hybrid thick-film time domain reflectometer. The design process allows for variation of the pulse generator characteristics as well as the output impedance of the unit. The unit is fabricated using standard thick-film hybrid techniques while giving consideration to …
-
Optimal filters for deconvolution of transient signals in the presence of noise
… different methods for the deconvolution of time domain signals. The techniques developed in this work are frequency domain filtering techniques. and are suitable for the type of deconvolution problems encountered in time domain reflectometry (TOR). They include a smoothing technique that is …
-
Rare earth-based active optical fiber device development
… sensing of temperature and strain using optical time-domain reflectometry techniques with such devices is also presented.
-
Calibration of time domain network analyzers
A calibration technique for time domain reflectometry and transmission (TDR and TDT) measurement system as applied to network analysis is presented. The calibration corrects for the errors caused by the response of the measurement system. A complete physically-based model has been established for …
-
Fiber optic techniques for remote sensing
… composite structures, relies on optical time - domain reflectometry in imbedded optical fibers. The method is investigated primarily in terms of its sensitivity and its effect on the mechanical integrity of the host composite. The work concludes with a discussion of results and ideas …
-
The Role of residual stresses in ceramic substrate materials for hybrid thick film applications
… are also tested for electrical performance using Time Domain Reflectometry (TDR) technique. This thesis presents results that indicate that significant tensile residual stresses were generated on the back of the substrate, particularly during the laser scribing phase of the finished device. …
Page 1 of 3