Electronic Theses and Dissertations

Identifier

6745

Date

2021

Document Type

Thesis

Degree Name

Master of Science

Major

Physics

Committee Chair

Firouzeh Sabri

Committee Member

Steve Allison

Committee Member

Jahan S Muhammad

Abstract

Phosphor thermometry offers many advantages over other temperature sensing techniques and is firmly established as a superior technique when compared to others such as infrared and resistive heating methods. The aim of the present work is to extend the application range of phosphor thermometry by exploring the feasibility of two new areas. In the first assessment, the temperature of tissue was evaluated by directly and indirectly interfacing thermographic phosphors with tissue. In the indirect method the temperature evaluated was the result of joule heating that occurred in a current carrying electrode mimicking an implant. The current was supplied by a DC supply. Results indicate that the signal transferred across the tissue boundary is in fact intense enough and clearly detectable to accurately infer temperature values from the decay curves associate with thermographic phosphors. The decay time was measured up to the thickness of 22.55 mm.. In the second part of the work the decay behavior of YAG:Dy coated on flexible ceramic strips of Yttrium Stabilized Zirconia (YSZ) was thoroughly investigated and characterized from ambient to 1200 °C. This was accomplished by 365 nm UV LED excitation and monitoring the 4I15/2 ®6H15/2 transition at 456 nm. The decay characteristics did not show a strong temperature dependence up to ~900°C. However, at temperatures exceeding 900°C there was a strong temperature dependence, such that the decay time decreased as a function of temperature.In the second part of the work the decay behavior of YAG:Dy coated on flexible ceramic strips of Yttrium Stabilized Zirconia (YSZ) was thoroughly investigated and characterized from ambient to 1200 °C. This was accomplished by 365 nm UV LED excitation and monitoring the 4I15/2 ®6H15/2 transition at 456 nm. The decay characteristics did not show a strong temperature dependence up to ~900°C. However, at temperatures exceeding 900°C there was a strong temperature dependence, such that the decay time decreased as a function of temperature.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.

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