Homepage of David Close
Department of Physics, East Tennessee State University
That's me in the ESR lab, B-24, Brown Hall.
Curriculum Vitae: OK, So make me an offer I can't refuse.
Publications: Most recent, and All publications.
- Over the years I have worked on a number of projects for various companies. One project
was to characterize various titanium dioxide catalysts for the Tennessee Eastman Co. in
Kingsport, TN. This work involved heat treating and evacuating the catalysts, and then
exposing them to gases or organic solvents. The nature of the chemical reactions that
occurred on these surfaces was characterized by ESR. A picture of the chemical preparation
process is shown here.
- I have also done some consulting for the Osteonics Corp. In Allendale, NJ. Osteonics makes
titanium hip joint replacements. To overcome the rejection problem, these devices are plasma
sprayed with bone material (hydroxyapatite). The coating is then irradiated for sterilization.
The high radiation dose caused the coating to yellow slightly. I used ESR to characterize the
nature of the radiation induced defects in the hydroxyapatite coating.
- I am currently consulting for the Institute for Energy and Environmental Research in
Washington, DC. The Institute seeks to provide the public and policy- makers with sound
scientific and technical studies on a wide range of issues. I have helped conduct a number of
workshops on assessing the risks of radiation to groups of atomic workers.
That's me, Ellen Kennedy (Staff member of IEER) and Arjun Makhijana (President of IEER).
- Jürgen Hüttermann (then at Regensburg) challenged the EPR community to find and
characterize the guanine cation. He promosed a case of his local Kneitinger beer to anyone
producing ESR evidence characterizing the guanine cation. This was around 1982. Bill
Nelson (Georgia State) and I had begun attempts to grow guanine crystals in strong acid. We
succeeded in growing several good size crystals of guanine hydrochloride monohydrate and of
guanine hydrochloride dihydrate (actually from the same preparation). We began the
ESR/ENDOR liquid helium and liquid nitrogens that summer. Our original experiments were
- At that time I had also begun a collaboration with Einar Sagstuen (Univ. Of Oslo). We talked
about trying to repeat our EPR experiments, and succeeded in producing the following angular
plot of the ESR data.
This is the X-band ESR angular plot of guanine hydrochloride monohydrate, x-irradiated and
observed at 77 K, showing evidence of the guanine cation (the weak outer lines of the spectra).
- When Jürgen saw this spectrum he knew that we had the guanine cation. He delivered the case
of Kneitinger to me at the Faraday Discussion Meeting in Leicester in 1984.
Back to Physics Homepage Back to Faculty and Staff