Homework Assignment #2 (12-06-2011)

Homework Assignment #2 (12-06-2011) - MAE 581 Advanced...

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1 MAE 581 Advanced Materials Science Homework Assignment #2 (12-06-2011) Requirement: your homework must be printed materials Problem 1 Write down the definitions of edge and screw dislocations. In the following 2-D lattice (distorted by dislocations), try to identify the types of dislocations at A, B, and C. Here open circles and black dots represent the atoms at different lattice layers. Let’s assume black dots are on the upper layer, and open circles are on the lower layer.
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2 Problem 2 Please carefully read the attached paper listed below: (1) Materials in extreme environments Please write down your comments and opinions. Requirement: (1) Your report should be at least one page long (single space) (2) Please use your own language to write your report (3) Your report must be a printed document (4) Hand-written report is NOT accepted One important issue about this assignment: (a) The attached document is a copyright-protected material. It can only be used for the learning activities in this course. Report due date: December 13, 2011 (the final exam date) (You should hand in your homework before the final exam) No excuse for late homework
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32 November 2009 Physics Today © 2009 American Institute of Physics, S-0031-9228-0911-010-4 Nature is rich with examples of phenomena and environ- ments we might consider extreme, at least from our familiar experience on Earth’s surface: large fluxes of radiation and particles from the Sun, explosive asteroid collisions in space, volcanic eruptions that originate deep underground, extraor- dinary pressures and temperatures in the interiors of planets and stars, and electromagnetic discharges that occur, say, in sunspots and pulsars. We often intentionally create similar extreme environments—for example, in high-powered lasers, high-temperature turbines, internal-combustion en- gines, and industrial chemical plants. The response of mate- rials to the broad range of such environments signals the materials’ underlying structure and dynamics, provides in- sight into new phenomena, exposes failure modes that limit technological possibility, and presents novel routes for mak- ing new materials. 1 Indeed, exposing materials to those regimes induces new physical phenomena that do not occur under ordinary conditions. Those extreme phenomena are central to many of the most fascinating grand challenges of science, including behavior far from equilibrium (see the article by Graham Fleming and Mark Ratner in PHYSICS TODAY, July 2008, page 28), planetary dynamics, the evolution of stars, and the origin of life on Earth. 2 Understanding and exploiting extreme environments is critical for facing major societal challenges—particularly in the area of energy—and goes back centuries. For example, Ben- jamin Franklin wrestled with the hazards of lightning in the mid-1700s, and Benjamin Thompson (later Count Rumford) studied the energetics of gunpowder during the American Revolution.
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Homework Assignment #2 (12-06-2011) - MAE 581 Advanced...

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