UK Professors Lighting the Way

Solar energy has been around for a while now, but John Anthony, Michel Jabbour and Chi-Sing Man are part of a team that was recently awarded a National Science Foundation grant to develop new ways to catch and convert light to electricity. Anthony, a chemist, describes the project, and his collaboration with mathematicians Jabbour and Man.

Designer Nanotubes: The role of Materials Synthesis in Application Driven Composites Engineering - Chemistry Seminar

Dr Rodney Andrews of University of Kentucky's Chemical & Materials Engineering department will be presenting a seminar entitled, "Designer Nanotubes: The role of Materials Synthesis in Application Driven Composites Engineering."

This is the Graffin Lectureship in Carbon Science and Engineering.  

The American Carbon Society, supported by grants from the Asbury Graphite Mills, Inc., sponsors this lecture series in North American Universities. The lecture series is in honor of George D. Graffin, who was a pioneer in the natural graphite industry. Each year the Society selects a lecturer who has made distinguished contributions to carbon science and engineering. The lecture is available to North American universities, by arrangement with the lecturer.
 
Abstract: Since their discovery, carbon nanotubes have been proposed as candidate materials for a broad range of applications, including high strength composites, molecular electronics, and energy storage. Carbon nanotube materials continue to attract attention from across the material sciences, primarily due to the unique physical properties of the nanotubes. Of particular interest is the effect nanotubes have on the thermal, electrical and mechanical properties of composite materials. While much effort has focused on exploiting the mechanical properties of carbon nanotubes, their thermal conductivity is also remarkable, 3000-6000 W/mK. In polymer composite materials, nanotubes have been shown to affect thermal transitions and the kinetics of their host matrix.
 
Carbon nanotubes are targeted for biomedical applications because of the many unique properties described above. They are known to extend the fatigue life of polymer systems, such as bone cement. Additionally, carbon nanotubes can reduce the risk for thermal necrosis by efficiently dissipating the heat generated in reacting polymer systems. These benefits can extend the clinical life of the material, will minimize the need for revision surgery thereby reducing associated health risks, and thus costs for the patient. Carbon nanotubes have numerous benefits in biomedical and dental applications and their associated composite materials can have a major impact in the treatment of disease, malformation, and trauma.
 
In this presentation, the use of multi-walled carbon nanotubes in a range of applications, including composites, separations, electrochemical energy storage, and as catalyst supports will be discussed. Synthesis, characterization and use of differing types of nanotube materials will be described, as well as their performance in the target applications. A study of carbon nanotubes in acrylic bone cement will be discussed and evidence that supports the inclusion of carbon nanotubes in biomedical applications will be presented. The potential for utilizing nanomaterials, especially carbon nanotubes, in biomedical and dental applications will also be explored.
 
Faculty Host: Dr. Meier
Date:
-
Location:
CP-137

Chasing Transient Molecules with Lasers, Molecular Spectroscopy of Radicals and Ions - Chemistry Seminar

Mohammed Gharaibeh of the UK Chemistry Department will be presenting a seminar entitled, "Chasing Transient Molecules with Lasers, Molecular Spectroscopy of Radicals and Ions."

Faculty Advisor: Dr. Clouthier
Date:
-
Location:
CP-137

A Novel Hydrophobicity Scale Derived from Membrane Protein Folding into Phospholipid Vesicles - Chemistry Seminar

Dr Karen Fleming of John Hopkins University will be presenting a seminar entitled, "A Novel Hydrophobicity Scale Derived from Membrane Protein Folding into Phospholipid Vesicles."

Abstract:
The protein-folding problem is one of the great challenges of contemporary biology. Knowing how the sequence for a protein encodes its fold would open a world of possibilities to molecular sciences that would no doubt include insights into evolution, genetic diseases as well as the ability to engineer proteins with novel functions. While soluble protein folding has been investigated for decades, similar studies on membrane proteins are, by comparison, in their infancy.
 
We have overcome many technical obstacles to successfully determine the thermodynamic stability of several membrane proteins. In dissecting transmembrane protein stability, we have discovered a novel hydrophobicity scale, and – for the first time – we are able to derive sequence–structure–energy relationships for a set of membrane proteins. Our progress has been enabled using the transmembrane beta-barrel, a protein fold that is uniquely suited for these investigations. However, we show that our findings are applicable to transmembrane alpha-helical proteins as well.
 
We are further investigating the dynamical process undergone by proteins as they insert into membranes. How is it that a membrane protein can be trafficked to its native membrane and know to fold there? By conducting kinetic experiments of the folding pathway both in the presence and absence of cellular assembly factors, we are able to propose and are testing functional roles for biological chaperones.
 
For more information about Dr. Fleming and her research, click here.
 
Faculty Host: Dr. Wei
Date:
-
Location:
CP-137

Dynamics of Polyatomic Free Radical Reactions - Chemistry Seminar

Dr Floyd Davis of Cornell University will be presenting a seminar entitled, "Dynamics of Polyatomic Free Radical Reactions."

Abtract: This talk will highlight two recent studies at Cornell aimed at better understanding the fundamental principles underlying chemical reactivity. Using the crossed molecular beams method, an atomic or molecular beam containing a highly reactive species is crossed with a second beam containing a stable molecule. The angular and velocity distributions of the neutral products from single reactive collisions are measured using mass spectrometry employing “soft” single photon ionization using pulsed vacuum ultraviolet light.

Vibrational vs. Translational Energy in Promoting a Metal-Hydrocarbon Insertion Reaction: 

There have been many previous studies of the role of vibrational energy in promoting abstraction reactions (e.g., Cl + CH4 → HCl + CH3). However, there have been very few studies of how vibrational energy promotes reactions initiated by insertion. The reactions of early transition metal atoms (Y, Nb, Zr, Mo) with simple hydrocarbons are simple prototypes for understanding hydrocarbon C-H and C-C bond activation. Previous work has shown that the reaction Y + CH4 → HYCH3 → YCH2 + H2 (Y = yttrium) is initiated by C-H insertion involving a 20 ± 3 kcal/mol potential energy barrier. In the present work, the reaction is studied in crossed molecular beams under two different conditions with nearly the same total energy. One experiment is carried out at a collision energy of 15.1 kcal/mol with one quantum of CH4 antisymmetric (ν3) stretching vibrational excitation (8.63 kcal/mol), the other at a collision energy of 23.8 kcal/mol. Our results are compared with results from other groups focusing on dissociative adsorption of CH4 on metal surfaces.

Collision Complex Lifetimes in the C6H5 + O2 Reaction: Does RRKM Theory Apply?

The reaction of phenyl radicals (C6H5) with molecular oxygen (O2) has been investigated at a range of collision energies. Here we detect the formation of the phenoxy radical, C6H5O from the C6H5O + O channel. The measured distributions imply that the reaction proceeds through formation of long-lived (τ >>1 ps) phenylperoxy intermediates, C6H5OO, followed by simple O-O bond fission. The interpretation of our measurements employing a pulsed C6H5 beam produced by 193 nm photodissociation of C6H5Cl sharply contrasts those of recent crossed beams investigations in which the C6H5 reactants were produced by pyrolysis of C6H5NO.

For more information about Dr. Davis and his research, click here.

Faculty Host: Dr. Yang
Date:
-
Location:
CP-137
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