Physical Sciences and Mathematics Commons^™

Thermal Property Measurement Of Thin Fibers By Complementary Methods, Troy Robert Munro

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Thin fibers are prevalent in many engineering materials. Measuring how well heat transfers in such small fibers can be difficult to determine, and previous methods have led to erroneous results. This dissertation details three proposed methods to improve the measurement of the thermal conductivity, thermal diffusivity, and volumetric heat capacity of thin fibers. Of particular interest is natural and synthetic spider silks because previously published values of the natural silk thermal conductivity was similar to copper, an excellent thermal conductor.

The three methods developed are the improved transient electrothermal technique (which was redeveloped to include radiation and convection heat losses …

A Structurally-Tunable 3-Hydroxyflavone Motif For Visible Light-Induced Carbon Monoxide-Releasing Molecules (Corms), Stacey N. Anderson, Jason M. Richards, Hector J. Esquer, Abby D. Benninghoff, Atta M. Arif, Lisa M. Berreau

Chemistry and Biochemistry Faculty Publications

Molecules that can be used to deliver a controlled amount of carbon monoxide (CO) have the potential to facilitate investigations into the roles of this gaseous molecule in biology and advance therapeutic treatments. This has led to the development of light-induced CO-releasing molecules (photoCORMs). A goal in this field of research is the development of molecules that exhibit a combination of controlled CO release, favorable biological properties (e.g., low toxicity and trackability in cells), and structural tunability to affect CO release. Herein, we report a new biologically-inspired organic photoCORM motif that exhibits several features that are desirable in a next-generation …

Laser Excited Fluorescence Of Dityrosine, Sahar F. Mahmoud, Stephen E. Bialkowski

Stephen E. Bialkowski

In this research, laser-excited fluorescence was examined for sensitive detection of aqueous dityrosine. Samples were excited with a 6.3-mW, 325-nm helium-cadmium laser focused into a small volume-fluorescence cell with a 10-cm lens. The resulting fluorescence emission was collected perpendicular to the excitation and detected with two different schemes. An optical bandpass filter was used with a photomultiplier tube for sensitive quantitative measurement, while a photodiode array detector was used in conjunction with a spectrograph for qualitative characterization of fluorescence emission spectra. Dityrosine detection on the order of 2 × 10^-11 M was obtained with the use of the photomultiplier …

Fluorescence Quenching At High Quencher Concentrations, David Peak, T C. Werner, R M. Dennin Jr., J K. Baird

All Physics Faculty Publications

Chemical reactions occurring in dense media at high reactant concentrations can be described by rate ‘‘constants’’ which are actually functions of concentration. We present a theoretical model in which this so‐called rate constant ‘‘renormalization’’ occurs for the specific case of fluorescence quenching in solution. We show that both the quenching and the excitation rate constants can become concentration dependent. We fit our theory to several sets of experimental data—our own and some from the literature—and show that excellent agreement is obtained by varying a single free parameter, namely, the efficiency with which a fluorophore‐quencher collision leads to a quench of …

Gas Phase Laser Induced Fluorescence Spectroscopy Of Cfcl, Stephen E. Bialkowski, David S. King, John C. Stephenson

Stephen E. Bialkowski

The CFCl radical has been produced in the gas phase by both IR multiphotonphotolysis of C₂F₃Cl and He metastable reaction with C₂F₃Cl. Single vibronic level fluorescence and excitation spectra taken of this species have yielded sufficient information to determine certain vibronic constants. The excited state was found to have an origin of T₀=25 283±5 cm⁻¹ with vibrational frequencies: ω₂′=394±3 cm⁻¹ and ω₃′=739±5 cm−1. In the ground state, the vibrational frequencies were found to be: ω₃″=118±10 cm⁻¹, ω₂″=448±6 cm …