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Dec 15, 2011

Dr. Asthana Presentation

1. What are grains and grain boundaries in a material? I suggest you focus on metals. Explain how material properties are affected by the size of these grains.
grain boundary is the interface between two grains, or crystallites, in a polycrystalline material. Grain boundaries are defects in the crystal structure, and tend to decrease the electrical and thermal conductivity of the material. The high interfacial energy and relatively weak bonding in most grain boundaries often makes them preferred sites for the onset of corrosion and for the precipitation of new phases from the solid. They are also important to many of the mechanisms of deformation. Reducing crystal size is a great way to increase strength between molecules

2. How does one engineer or process materials to reduce the grain size? In particular, I would like for you to explore and then explain how single crystal silicon is produced for the solar industry.
Grain size is often determined by the rate at which the material cooled during forming. If you can melt the material and then cool it rapidly, that would create small grains. Using methods to first purify the substance, could use extreme amounts of heat boiling out undesired, then rapidly cool it to berid of grains.

Dec 6, 2011

Blog post 13: Nano and Proteins

1. MALDI stands for Matrix assisted laser desorption/ionization it is used for predicting polymer properties and morphology. http://www.psrc.usm.edu/mauritz/maldi.html

2. Microcystin LR: http://www-cyanosite.bio.purdue.edu/cyanotox/toxins/MCYSTLR.gif
Collagen: http://www.3dchem.com/imagesofmolecules/Collagen2.jpg
Hemoglobin: http://www.files.chem.vt.edu/confchem/2004/b/sinex-gage/hemoglobin_stick.gif

3. Microcystin LR: 200nm
Collagen: 300nm long 1.5nm in diameter
Hemoglobin: 600-900nm

4.Liquid proteins in protein synthesis http://pubs.acs.org/doi/abs/10.1021/nn202290g

Blog Post 12: Invention Background/references


2) Preparation and Characterization of Nano-NTO Explosive.

3) Generation and characterization of nano aluminum powder obtained through wire explosion process.

4) Production and Characterization of Nano Copper Powder Using Pulsed Power Technique.

5) Solution combustion synthesis of nano particleLa<sub>0.9</sub>Sr<sub>0.1</sub>MnO<sub>3</sub> powder by a unique oxidant-fuel combination and its characterization.

6) Structure, Thermal Properties, and Combustion Behavior of Plasma Synthesized Nano-Aluminum Powders.

7) Nano-Blast Synthesis of Nano-size CeO<sub>2</sub>–Gd<sub>2</sub>O<sub>3</sub>Powders.

8) Nano-MnFe<sub>2</sub>O<sub>4</sub> powder synthesis by detonation of emulsionexplosive.

9) Dense-Phase Pneumatic Conveying Technology for Highly Explosive Metal Powders.

10) Ablation combustion of secondary powder explosives.