Transient Radicals Produced by Sonication and the Investigation of Paramagnetic Effects

dc.contributor.authorMcCreary, Kaceyen
dc.contributor.committeechairMadsen, Louis A.en
dc.contributor.committeememberBrewer, Karen J.en
dc.contributor.committeememberTanko, James M.en
dc.contributor.departmentChemistryen
dc.date.accessioned2014-03-14T21:47:28Zen
dc.date.adate2012-11-13en
dc.date.available2014-03-14T21:47:28Zen
dc.date.issued2012-09-28en
dc.date.rdate2012-11-13en
dc.date.sdate2012-10-11en
dc.description.abstractUltrasound can be used to create free radicals by growth and collapse of cavitation bubbles. These free radicals have potential use in various fields. The formation of free radicals can be monitored by decrease in T1 during NMR experiments due to paramagnetic effects. Our goal is to develop a method in which ultrasound is used to enhance NMR. By irradiating the sample during analytical measurements, we can decrease T1 which can be used as a non-toxic contrast agent1 producing hydroxyl radicals from the water in the body, invoke NMR enhancement using dynamic nuclear polarization2, control and understand polymer reactions3,4, and study the formation of radicals in chemical systems with EPR5. The experiments conducted indicated a decrease in T1 when ultrasound was applied. A maximum decrease was observed when 104 W of ultrasound power was applied and with higher concentrations of radical producing species. Through the experiments it was evident that the sample temperature increased during sonication. To counter this, gated sonication was used to minimize temperature increase. During sonication, the sample was vigorously mixed. Experiments where the sample was mixed through alternate means and theoretical simulations indicate that sample mixing gives an apparent decrease in T1. In situ sonication to decrease T1 shows promise. The question remains if the decrease is due to a combination of radical production and mixing or just an artifact of sample mixing. This is a difficult parameter to determine but future experiments will attempt to supply further conclusions.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-10112012-224257en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-10112012-224257/en
dc.identifier.urihttp://hdl.handle.net/10919/45147en
dc.publisherVirginia Techen
dc.relation.haspartMcCreary_KB_T_2012.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectfree radicalen
dc.subjectsonicationen
dc.subjectT1 relaxationen
dc.subjectNuclear Magnetic Resonanceen
dc.titleTransient Radicals Produced by Sonication and the Investigation of Paramagnetic Effectsen
dc.typeThesisen
thesis.degree.disciplineChemistryen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

Files

Original bundle
Now showing 1 - 1 of 1
Loading...
Thumbnail Image
Name:
McCreary_KB_T_2012.pdf
Size:
6.02 MB
Format:
Adobe Portable Document Format

Collections