Researchers discover theoretical model to predict jamming
April 25, 2008Researchers at the UCLA Henry Samueli School of Engineering and Applied Science have come up with a theoretical model to predict when granular materials become jammed. This advancement not only broadens fundamental knowledge, it also provides new avenues to a number of practical areas that ranges from materials innovation to medicine. The study, currently available on the Nature Physics Web site, will be published in the journal's print edition on May 1.
“We started this research by looking at the behavior of dry powders as solid lubricants as well as the behavior of a powdered rock in fault zones called gouge during an earthquake. What we found led us to a model that can accurately predict the behavior of dense granular flows. What we realized soon after was that the granular particles interact similarly to that of molecules in materials that jam, such as colloids and foam” said study’s author Pirouz Kavehpour, an assistant professor of mechanical and aerospace engineering and director of the Complex Fluids & Interfacial Physics Laboratory at UCLA. “From there, we were able to find a universal law that can predict the jamming behavior for the first time.”
According to Emily Brodsky, associate professor of earth and planetary sciences at UC Santa Cruz and also an author of the study, “We understand how water flows. We understand how honey flows. We even understand how elastic bands deform. But granular flows are complicated and hard to understand. If you’re pouring sand down a hill or in an hour glass, there was never a good formula for the strain or the strain rate as a function of stress. This formula is definitely new and unique.”
Kevin Lu, UCLA graduate student and lead author of the study, showed that the formula also quantified glass-transition. “Glass is a solid that flows. But structurally, it’s a liquid. The molecules in a glass are jammed and unable to flow past each other so the material actually flows sluggishly. One evidence of this can be found in the window panes of old churches in Europe. Studies have shown that the bottom of the windows are consistently thicker than the top. Glassy liquids flow very much in the same manner as granular media.” said Lu.
This new theoretical framework, the authors believe, can be applied to many different areas. Pharmaceutical companies can use the new equation to decide the size and quantities of pills that may or may not fit through a shoot that fills containers. Also, from knowing the fundamentals of jamming, scientists can now engineer materials that are both durable and strong. Instead of working with composites or alloys, the jamming theory provides a roadmap to tune material properties from pure substances.
“It can also help us to better understand certain diseases in medicine. In sickle cell anemia, for example, the abnormal blood cells are long and skinny, resulting in the obstruction of blood flow to various organs. Now we can do more to reduce the likeliness of death-threatening implications to benefit the medical community,” said Lu.
As a geologist who studies fault zones and earthquakes, Brodsky is particularly interested in the granular flow of gouge found in fault zones and having a formula to figure out when the rock is jammed and when it’s free flowing can be significant.
“Knowing how things flow and the granular behavior in a fault zone is one of the very important steps in trying to figure out how exactly faults slip,” said Brodsky.
Source: University of California - Los Angeles
-
The Drive for Data Protection
Apr 17, 2007 |
4 / 5 (3) |
0
-
Study shows how granular materials get themselves out of a jam
Jun 22, 2005 |
4 / 5 (1) |
0
-
How granular material becomes solid: Stress causes clogs in coffee and coal
Dec 14, 2011 |
5 / 5 (4) |
4
-
Big success with tiny crystals
Nov 30, 2011 |
5 / 5 (2) |
0
-
Rethinking equilibrium: In nature, large energy fluctuations may rile even 'relaxed' systems
Oct 31, 2011 |
4.8 / 5 (5) |
3
-
Engineers build first sub-10-nm carbon nanotube transistor
Feb 01, 2012 |
4.9 / 5 (33) |
30
-
Something old, something new: Evolution and the structural divergence of duplicate genes
Jan 31, 2012 |
4.6 / 5 (7) |
1
-
The hidden nanoworld of ice crystals: Revealing the dynamic behavior of quasi-liquid layers
Jan 30, 2012 |
5 / 5 (4) |
1
-
Stock market network reveals investor clustering
Jan 27, 2012 |
3.9 / 5 (23) |
8
-
Of microchemistry and molecules: Electronic microfluidic device synthesizes biocompatible probes
Jan 26, 2012 |
5 / 5 (2) |
0
-
Can Plasma Be Solid
4 hours ago
-
What is delta Δ ?
5 hours ago
-
Need some help understanding Hertz–Knudsen formula
5 hours ago
-
Anatomy of Fat man: implosion-critical bomb
7 hours ago
-
what makes two sounds similar???
8 hours ago
-
What would happen when a jet travelling at Mach 10 experiences engine failure
14 hours ago
- More from Physics Forums - General Physics
More news stories
Explained: Sigma
It's a question that arises with virtually every major new finding in science or medicine: What makes a result reliable enough to be taken seriously? The answer has to do with statistical significance -- but ...
Feb 09, 2012 |
5 / 5 (20) |
76
Quantum physicist explains $100K offer for proof scaled-up quantum computing is impossible
(PhysOrg.com) -- MIT researcher Scott Aaronson has certainly riled the physics community with his offer this past Friday, of $100,000 to anyone who can prove that scaled-up quantum computing is impossible. ...
Diamond light, brighter than the sun
Its the size of five football pitches and generates light 10 billion times brighter than the sun. As the Diamond Light Source celebrates its tenth anniversary this year, Penny Bailey visits one of the ...
Feb 07, 2012 |
4.1 / 5 (10) |
18
|
Physicists 'record' magnetic breakthrough
An international team of scientists has demonstrated a revolutionary new way of magnetic recording which will allow information to be processed hundreds of times faster than by current hard drive technology.
Feb 07, 2012 |
4.6 / 5 (43) |
15
|
Hints of the Higgs - papers are submitted
Back in December 2011, the ATLAS and CMS experiments at CERN presented some exciting results that provided tantalising hints of the Higgs boson.
Feb 08, 2012 |
4.3 / 5 (8) |
10
Scientists discover molecular secrets of 2,000-year-old Chinese herbal remedy
For roughly two thousand years, Chinese herbalists have treated Malaria using a root extract, commonly known as Chang Shan, from a type of hydrangea that grows in Tibet and Nepal. More recent studies suggest that halofuginone, ...
New method to examine batteries -- MRI from the inside
There is an ever-increasing need for advanced batteries for portable electronics, such as phones, cameras, and music players, but also to power electric vehicles and to facilitate the distribution and storage of energy derived ...
Google might launch Drive for cloud storage soon
(PhysOrg.com) -- Google's next big move, according to the Wall Street Journal, is a cloud storage service called Drive. Hardly first to the plate, Google is simply catching up to introducing its cloud reposi ...
A mitosis mystery solved: How chromosomes align perfectly in a dividing cell
Although the process of mitotic cell division has been studied intensely for more than 50 years, Whitehead Institute researchers have only now solved the mystery of how cells correctly align their chromosomes during symmetric ...
Lab study raises questions over nano-particle impact
Tests involving chickens have raised questions about the impact on health from engineered nano-particles, the ultra-fine grains commonly used in drugs and processed foods, scientists said on Sunday.
Starve a virus, feed a cure? Findings show how some cells protect themselves against HIV
A protein that protects some of our immune cells from the most common and virulent form of HIV works by starving the virus of the molecular building blocks that it needs to replicate, according to research published online ...