2012 Fall Graduate Colloquium Series: Bao-Fei Li/Bahram Shakerin

DateNovember 9, 2012Time3:35 - 5:00 pm
LocationBaylor Sciences Building, Room E.125
Bao-Fei Li

Friction Control Between Two Polyelectrolyte Layers

Polyelectrolyte (PE) coatings can act as very effective lubricants for the reduction of friction between two rubbing surfaces. For two PE-coated surfaces, macroscopic friction is dependent on the degree of interpenetration between two PE layers at molecular scale. By adjusting external physical fields, such as electric fields, the friction force is subjected to a dramatic and reversible reduction resulting from changes in PE brush interpenetration. Moreover, at larger loads, which will cause more overlapping between PE chains of opposing PE layers and consequently lead to larger resistance, the lubrication property of PE layers is also greatly improved by external electric fields. Besides, the effect of field's frequency on the friction is also interesting and more revealing since friction appears absent in a narrow frequency window.

Bahram Shakerin

Quantum Gravity and Planck-scale Physics

Combining quantum theory and the theory of general relativity into a unified framework has been important since 1939. We start with the motivations for quantizing gravity. After a very short review of the most important approaches toward quantum gravity and the difficulties that we would encounter, we concentrate on the Planck-scale physics and the importance of minimal length. The existence of a minimal length scale is widely expected to result in a modification of the Heisenberg uncertainty relation. After that, we introduce a scheme to experimentally test this conjecture.

For more information contact: Dr. Linda Olafsen 254-710-2541

PublisherDepartment of Physics
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