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METHOD:PUBLISH
BEGIN:VEVENT
DTSTAMP:20260917T194047Z
LAST-MODIFIED:20150205T152507Z
DTSTART:20150224T203000Z
DTEND:20150224T213000Z
UID:event1358@bu.edu
URL:http://physics.bu.edu/internal/events/show/1358
SUMMARY:A Rough View of Friction and Adhesion
DESCRIPTION:Featuring Mark Robbins\, Johns Hopkins University\nHosted by: D
	avid Campbell\nPoster: http://physics.bu.edu/internal//files/get/022415-rob
	bins.pdf\n\nPart of the Physics Department Colloquia Series.\n\nAbstract:\n
	Friction affects many aspects of everyday life and has played a central rol
	e in technology dating from the creation of fire by rubbing sticks together
	 to current efforts to make nanodevices with moving parts. The friction "la
	ws" we teach today date from empirical relationships observed by da Vinci a
	nd Amontons centuries ago. However\, understanding the microscopic origins 
	of these laws remains a challenge. While Amontons said friction was proport
	ional to load and independent of area\, most modern treatments assume that 
	friction is proportional to the real area of contact where atoms on opposin
	g surfaces are close enough to repel. Calculating this area is complicated 
	because elastic interactions are long range and surfaces are rough on a wid
	e range of scales. In many cases they can be described as self-affine fract
	als from nanometer to millimeter scales. The talk will first show that this
	 complex problem has a simple solution. Dimensional analysis implies a line
	ar relation between real contact area and load that can explain both Amonto
	ns' laws and many exceptions to them. Next the talk will explain why we can
	't climb walls like spiderman even though the attractive interactions betwe
	en atoms on our finger tips should provide enough force to support our weig
	ht. The talk will conclude by considering how forces in the contact area gi
	ve rise to friction. Friction shows surprisingly counterintuitive and compl
	ex behavior in nanometer to micrometer scale contacts and only a few explan
	ations are consistent with macroscopic measurements.
LOCATION:SCI 109\, 590 Commonwealth Avenue\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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