Andrew F. McDowell

Conduction-electron mediated 1H nuclear spin-lattice relaxation in Ti45Zr38Ni17H x icosahedral quasicrystals

Nuclear magnetic resonance spin-lattice relaxation rates for 1H in quasicrystalline Ti45Zr38Ni17H x are presented as a function of temperature and hydrogen concentration x. The temperature dependence demonstrates that the relaxation is via interaction with conduction electrons. The relaxation rate is extremely sensitive to hydrogen content, with the rate changing by a factor of as much as two for samples that differ in x

Bioagent detection using miniaturized NMR and nanoparticle amplification : final LDRD report.

This LDRD program was directed towards the development of a portable micro-nuclear magnetic resonance ({micro}-NMR) spectrometer for the detection of bioagents via induced amplification of solvent relaxation based on superparamagnetic nanoparticles. The first component of this research was the fabrication and testing of two different micro-coil ({micro}-coil) platforms: namely a planar spiral NMR {micro}-coil and a cylindrical solenoid NMR {micro}-coil. These fabrication techniques are described along with the testing of the NMR performance for the individual coils. The NMR relaxivity for a series of water soluble FeMn oxide nanoparticles was also determined to explore the influence of the nanoparticle size on the observed NMR relaxation properties. In addition, The use of commercially produced superparamagnetic iron oxide nanoparticles (SPIONs) for amplification via NMR based relaxation mechanisms was also demonstrated, with the lower detection limit in number of SPIONs per nanoliter (nL) being determined.