Contact Information

Phone: (610) 758-4781
FAX: (610) 758-5057
e-mail:gilchrist@lehigh.edu
http://chaos.cc.lehigh.edu/

Research Interests

Self-organization can be loosely defined as the spontaneous emergence of higher order from many individual interactions. Widely seen in natural systems, self-organization is an increasingly promising mode of design and assembly of materials and devices. This is especially advantageous at small length scales (nanometers to microns) where direct manipulation of constituents can be difficult and expensive. Conversely, it is evident in other applications, such as those where mixing is essential, that self-organization and segregation of ingredients is undesirable. My research focuses on understanding methods of promotion and/or inhibition of self-organization in model dynamic systems to enhance assembly and mixing.

Both colloidal and granular systems may be regarded as model systems that display dynamic self-organization, resulting from many particle-particle and particle-flow interactions. I am interested in the mechanism of particle self-organization, how it occurs at many length scales, and how these interactions can be manipulated to control mixing, segregation, and assembly. In one such project, I am currently studying these processes in microfluidic devices where boundary conditions are well defined and particle-particle and particle-flow interactions can be investigated directly. Knowledge derived from model processes will be used both for understanding and enhancing existing processes that currently take advantage of self-organization as well as for designing new systems and advanced materials.

Selected Refereed Journal Articles
"Power Consumption and Granular Flow in a Vibro-Fluidized Stirred Granular Bed", K. J. Ford, J. F. Gilchrist, and H. S. Caram, submitted.

"Investigation of the Deposition of Microsphere Monolayers for Fabrication of Microlens Arrays", P. Kumnorkaew, Y. Ee, N. Tansu, and J. F. Gilchrist, Langmuir, in press.

"Shear-Induced Particle Migration in one-, two-, and three-dimensional Flows", C. Gao and J. F. Gilchrist, Physical Review E, 77, 025301, 2008.

"Enhancement of Light Extraction Efficiency of InGaN Quantum Wells Light Emitting Diodes Using SiO2 Microspheres", Y. K. Ee, R. A. Arif, P. Kumnorkaew, N. Tansu, and J. F. Gilchrist, Applied Physics Letters, 91, 221107, 2007.

"Phase Behavior and 3D Structure of Strongly Attractive Microsphere-Nanoparticle Mixtures", J. F. Gilchrist, A. T. Chan, E. R. Weeks, and J. A. Lewis, Langmuir, 24, 11040, 2005.

"Competition Between Chaos and Order: Mixing and Segregation in a Spherical Tumbler", J. F. Gilchrist and J. M. Ottino, Physical Review E, 68, 061303, 2003.

"Segregation-Driven Organization in Chaotic Granular Flows", K. M. Hill, D. V. Khakhar, J. F. Gilchrist, J. J. McCarthy, and J. M. Ottino, Proceedings of the National Academy of Sciences, 96(21), pp. 11701-11706, 1999. (Cover Article)

"Mixing of Granular Materials: A Test-Bed Dynamical System for Pattern Formation", K. M. Hill, J. F. Gilchrist, D. V. Khakhar, J. J. McCarthy, and J. M. Ottino, International Journal of Bifurcation and Chaos, 9, pp. 1467-1484, 1999. (Cover Article)

"Chaotic mixing of granular materials in two-dimensional tumbling mixers", D. V. Khakhar, J. J. McCarthy, J. F. Gilchrist, and J. M. Ottino, Chaos, 9(1), pp. 195-205, 1999.