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 14 of 14 for “"conductivity changes"”.
-
Investigation of Machine-Learning Techniques for Pulmonary Artery Pressure Estimation from Electrical Impedance Tomography Images
… on the known association between thoracic conductivity changes and PAP. This thesis attempted to improve these results by predicting PAP using neural networks (NN). Multiple NN architectures were trained and tested on a dataset of eight cardiac failure patients, and their prediction …
-
Mechanism and Applications of large and persistent photoconductivity in cadmium sulfide
Photoconductivity is the phenomenon where electrical conductivity changes as a result of photoexcitation of new charge carriers. In some semiconductors, photoconductivity is accompanied with enormous conductivity change and long decay time after photoexcitation is ceased. This effect is called …
-
Layer-by-layer assembly of conducting membranes for photoelectrochemical cells
… Transparent mixed conducting polymer films with conductivity above 0.1 mS/cm are highly desirable for photoelectrochemical cell membrane applications. Mixed conducting polymer composite PEDOT:sPPO was incorporated into LbL films and the composition ratio of the film components was varied to …
-
Expanding ultrafast photoacoustics for investigation of mechanical properties and thermal transport
… properties and thermal phonons. Next, thermal conductivity reduction due to carrier-phonon interactions was presented. Phonon contributions are critical in heat transport in semiconductors and insulators. To isolate the carrier contributions to the scattering events, photo-excited carriers were …
-
Electrical Impedance Tomography for Perfusion Imaging and Monitoring
… electrodes which are in turn used to reconstruct conductivity changes within the body. EIT has been studied for its ability to image both the flow of blood and the delivery of blood to a tissue (perfusion). However, cardiac-related signals are challenging to image accurately due to their small …
-
Guided Wave Actuation for Enhanced Damage Identification in Carbon Fiber Reinforced Polymer Material Using Electrical Resistance Tomography
… injections in the material to measure electrical conductivity changes induced by damage. Accurate and efficient damage identification in CFRP composites using ERT with hardware limitations on sensor measurements requires techniques for selecting optimum sensing combinations. A novel method to …
-
Photoconductivity studies of the ferrocyanide ion under high pressure
… was developed for the investigation of photoconductivity phenomena in liquids pressurized up to 10 kbar. A variety of exciting light sources could be used. In nonpolar solvents, with an applied d.c. voltage, photo-currents as small as 10 p.a. could be resolved. In aqueous solutions, with an …
-
Modeling the TDEM response for a lateral change in conductivity
… of the solution for a 2D or 3D earth, where the conductivity changes in not just the z-direction, is extremely difficult and has only been done by way of numerical schemes, which are laborious even on powerful computers. In this study a current filament is used to generate magnetic fields and its …
-
Regularisation methods for imaging from electrical measurements
In Electrical Impedance Tomography the conductivity of an object is estimated from boundary measurements. An array of electrodes is attached to the surface of the object and current stimuli are applied via these electrodes. The resulting voltages are measured. The process of estimating the …
-
Surface states on the cleaved (III) silicon surface
Conducti vi ty changes resulting when sing.le crystal silicon is cleaved in ultrahigh vacuum have been measured parallel to the cleavage plane over various temperature ranges for gold dope~ and high.resistivity boron doped silicon. The resulting change of conductivity is related to the difference …
-
Non-Linear Magnetosphere-Ionosphere Interactions at High Latitudes
… excited in the ionosphere by changing the conductivity in the E-region when the large-scale electric field exists in the heating region.</p> <p>The importance of the Hall currents in magnetosphere-ionosphere interactions, carried by ULF waves and field-aligned currents, has been …
-
Air Ingress in HTGRs: the process, effects, and experimental methods relating to its investigation and consequences
… studies were performed to determine the changes induced in nuclear grade graphite exposed to high-temperature, oxidizing flow of varying flow rates. Under all scenarios, the thermal diffusivity of the graphite test samples was shown to increase. Thermal conductivity changes due to …
-
Characterisation of thin-film semiconductors for device application
… have been investigated using dark- and photo-conductivity measurements, constant photocurrent method and transient photoconductivity. The dark conductivity was measured as a function of temperature; the photoconductivity was measured with steady state and transient excitation as a function of …
-
STORMWATER MANAGEMENT PRACTICE MONITORING USING LONG-TERM TIME LAPSE ELECTRICAL RESISTIVITY TOMOGRAPHY AND SOIL SENSORS: IMPLICATIONS FOR DESIGN, MAINTENANCE, AND SOIL MOISTURE MONITORING
… resistivity (the inverse of electrical conductivity). If multiple surveys are taken over time, the data can be differenced, known as time lapse inversion, to quantify changes in electrical resistivity. ERT is a favorable for these SMPs as survey results are sensitive to changes in soil …