Applied Math Colloquium

Friday, April 12, 2013, 11:30 AM
Cullimore Lecture Hall, Lecture Hall II
New Jersey Institute of Technology


The physics of powers flow - dilation, segregation, and jamming - where is the math?

Fernando Muzzio


Rutgers University



For you were made from dust, and to dust you will return... (Genesis 3:19)

Powders are immensely important to human enterprise.

From a scientific perspective, particle interactions are part of the essential physics controlling soil and sand avalanches, beach erosion, and soil and rock strength.

In technology, most manufacturing industries rely at least in part on powder mechanics and particle technology, including, among many, pharmaceuticals, petroleum extraction from tar sand, 3D printing, ceramics, coal processing, food manufacturing, construction, agrochemicals, mining, hard metals processing, and a myriad others, account for perhaps a trillion dollars of yearly economic activity in the US alone, and four times as much worldwide.

and yet...

- We do not have mathematical models that effectively describe how powders flow.

- Powder segregation, a widespread phenomenon that captivates physicists, daunts engineers, and destroys the quality of many products ranging from medicine to blue cheese curmbs, has resisted a mathematical description.

- Jamming is a remarkable phenomenon, causing powders to form bridges and arches across discharge tubes, causing flow to stop. To the best of my knowledge, no mathematical description of this phenomenon has been attempted.

- Even the shapes of particles, the statistics of surface behavior, and the composition distributions of powder blends remain obscure, due to the divergent nature of particle size distributions.

In this talk, I will share some of the joys and frustrations of twenty-two years dealing with these problems.