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 133 for “"Reflectometry"”.
-
Acoustic Frequency Domain Reflectometry
Acoustic Frequency Domain Reflectometry (AFDR) is a novel technique employing frequency modulated continuous wave (FMCW) methods in solid acoustic waveguide reflectometry. It is particularly suited to dispersion compensation and phase compensation due to the measurement domain being the frequency …
-
Reflectometry measurements on alcator C-mod
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1997.
-
Dynamic Strain Measurement Using Brillouin Optical Time-Domain Reflectometry
… 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 information is …
-
Temperature corrected strain measurements using optical time domain reflectometry
… 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 are presented …
-
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 …
-
Acoustic pulse reflectometry for the measurement of musical wind instruments
… The time domain technique of acoustic pulse reflectometry can be used to measure the input impulse response of a tubular object, such as a wind instrument, from which both its bore profile and input impedance can be calculated. In this thesis, after a discussion of the theory of acoustic …
-
Time-Frequency Localisation of Distributed Brillouin Optical Time Domain Reflectometry
… 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 parameters of distributed fibre optic sensors, spatial and frequency resolution, are …
-
Optical Frequency Domain Reflectometry Based Quasi-distributed High Temperature Sensor
… room temperature. An optical frequency domain reflectometry (OFDR) based multiplexed technique is applied in the sensor design to realize temperature measurement at multiple locations along the optical path. In this work, three sapphire wafers based multiplexed temperature sensor is fabricated …
-
Improvements to the acoustic pulse reflectometry technique for measuring duct dimensions
… instruments and human airways, acoustic pulse reflectometry has become established as a useful tool for non-invasively measuring the input impulse response, from which the internal duct dimensions can be calculated. In this thesis, the theory describing wave propagation in a duct of varying …
-
Time domain reflectometry (TDR) techniques for the design of distributed sensors
… 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 cable …
-
Oblique-incidence fiber-optic reflectometry for measuring absorption and scattering in turbid media
Oblique-incidence, fiber-optic reflectometry is a simple and accurate method for measuring the absorption and reduced scattering coefficients, $\mu\sb{a}$ and $\mu\sb{s}\sp\prime ,$ of semi-infinite turbid media. Obliquely incident light produces a spatial distribution of diffuse reflectance that …
-
Experimental application and numerical study of reflectometry in the Alcator C-Mod tokamak
… to simulate and quantitatively interpret reflectometry signals. The code uses the finite-difference time-domain method to solve Maxwell's equations in two dimensions. Perfectly-matched layers are used as the boundary. The Huygens source technique is used to generate Gaussian beams and …
-
The effects of moving electron density fluctuations on time domain reflectometry in plasmas
… 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 specified static electron density profile, …
-
POTENTIAL OF TERAHERTZ PULSED REFLECTOMETRY AND IMAGING FOR THE EARLY DIAGNOSIS OF CUTANEOUS MELANOMA
… the practicality and benefits of using terahertz reflectometry for the early diagnosis of melanoma has never been performed. Therefore, as a pilot study, an investigation into the modalities of utilising terahertz technology on freshly excised human cutaneous melanoma is anticipated, which …
-
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 …
-
Global Navigation Satellite Systems as Signals of Opportunity for Environmental Applications: Reflectometry and Scintillation
L'abstract è presente nell'allegato / the abstract is in the attachment
-
Multi-defect localization and evaluation techniques for distribution cables based on time-domain reflectometry
… 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 …
-
Structural Monitoring With Fiber Bragg Grating Strain Sensor Array and Optical Frequency Domain Reflectometry
… in the use of Coherent Optical Frequency Domain Reflectometry (C-OFDR) to interrogate Fiber Bragg Grating Arrays (FBGA) have shown promise in its use in infrastructure health monitoring systems. In this work, the modeling, design, simulation, fabrication, calibration, and testing of a …
-
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 …
Page 1 of 7