Scientific innovations and applications- the key to growth and sustenance of quality of life in the 21st century

Kapila Gunasekera, Shibalik Chakraborty, Chad Holbrook, Sriram Ravindren and Vignarooban Kandasamy, and Punit Boolchand University of Cincinnati http://www.ece.uc.edu/~pboolcha/

25 new discoveries of 2012 , Time Magazine, Nov. 12, 2012

Solar powered distiller

States of matter

Liquids Solids water ice (disordered) (ordered)

These are atomic networks

LiquidSolidTf or Tl

What is so special about these very select melts that can bypass crystallization and form a glass? Here I will show you that these melts possess an ideal connectivity.

There are deep theoretical, applied and technological consequences of this finding.

Quartz (SiO2) Crystal

Corning Glass https://www.youtube.com/watch?v=aVxj6gRYwS0https://www.youtube.com/watch?v=FCR8NDq-jmw&feature=fvsr

3 4 5 6 7

Si crystal structure

Disordered- Ordered

r, Coordination number, = 46 bond angles but only 5 are independent4 bonds

Each bond-angle and bond-length serves as mechanical constraints. nc = 5 + 2 = 7

nc = 2r-3 + r/2 = ( 5/2)r - 3 12340Tetrahedral Coordination

r = 2nc = (5/2)r 3 = 2123Chain structure of crystalline Selenium

Degrees of freedomAn atom moving in a 3D space can move either along the x-axis, or the y-axis or the z-axis. An atom in 3D space has 3 degrees of freedom.

Ideal networks ? Ideal networks form when the degrees of freedom exactly match the count of mechanical constraints. Thus, for example, a 3D network would be ideal if every atom in the network had 3 constraints on an average.

Si is an example of a highly over-constrained network. There are nc = 7 constraints/atom.

On the other hand, Se is an example of an under-constrained network, since nc = 2.

How are we to get an ideal network out Si and Se? If we were to mix 20 atoms of Si with 80- atoms of Se, what would be the count of constraints for such a mixture? nc of a mixture of Si20Se80 composition, = 7 x 0.20 + 2 x 0.80 = 3.0 would become ideal !!!! And one might expect these binary melts/ glasses to show anomalies near 20% of Si.

In nature the glass forming tendency is optimized near this magic connectivity of nc = 3 !!!! - J.C. Phillips 1979 (Jour. Non Cryst. Solids)

Thermally reversing window in binary GexSe100-x bulk glassesX.Feng et al. Phys. Rev. Lett. 78,4422(1997).S.Bhosle et al. Sol.St. Commun. 151, 1851(2011)P.B et al. in Rigidity and IPs , Chapter 1, Pp1-36 (2009).

Functional Disordered networks Each may have at its base a self-organized phase that endows these systems with unusual functionalities. PB, G.Lucovsky, J.C.Phillips and M.F.Thorpe, Phil. Mag.85, 3823 (2005).

***The animated slide shows how discovery of Intermediate phases in disordered networks has consequences a variety of disciplines.