Register for updates

 
 

Environment & Ecology
RSS Feed
Solving the Riddle of the Snow Globe
Thursday, May 25, 2017 9:30:00 AM

TAU research explains the process of sedimentation in natural and industrial contexts

If you've shaken a snow globe, you've enjoyed watching its tiny particles slowly sink to the bottom. But do all small objects drift the same way and at the same pace?

A new Tel Aviv University study finds the sedimentation of asymmetric objects in liquid is very different from that of symmetrical objects like spheres. The research solves a long-standing puzzle concerning the cause and the extent of "storminess" in sedimentation, and may be useful in improving water treatment and industrial processes that rely on suspensions, which are liquids that contain small solid particles. The research may also have use in the study of geological deposits, because variations in the concentration of particles from place to place affect the progress of sedimentation.

The research was led by Prof. Haim Diamant of TAU's School of Chemistry in collaboration with Prof. Thomas Witten of the University of Chicago, and conducted by TAU doctoral student Tomer Goldfriend. It was sponsored by the US-Israel Binational Science Foundation (BSF) and published in Physical Review Letters.

The calm and the storm

"Our research clarifies a common, complex phenomenon and offers ways of controlling it," Prof. Diamant said. "We have demonstrated that the 'storminess' of sedimentation is specific to symmetrical objects such as spheres and ellipsoids. It disappears in the more general case of asymmetric objects, which can have arbitrary shapes. Asymmetric objects render the sedimentation process more uniform and less chaotic."

Certain chemical reactors and water-treatment facilities rely on processes closely related to sedimentation, Prof. Diamant explained. "These are called 'fluidized beds,' where settling particles are made to hover in the liquid by an opposing upward flow of liquid, which facilitates their chemical activity. Fluidized beds are used in the production of polymers such as rubber and polyethylene. They are also used to improve the efficiency of water and waste treatment facilities. Our work might lead to improvements of such processes by controlling the uniformity of particles distributed in the liquid."

The team is currently studying the organizational properties of other kinds of materials. "We now intend to look for physical scenarios other than sedimentation that may show a similar kind of 'self-taming' — that is, a tendency of the material's constituents to self-organize into extremely uniform configurations," Prof. Diamant said. "The basic question is whether the behavior that we have found is unique to the process of sedimentation or can be found in a much broader class of materials. We think — we hope — that the latter is true."




Latest News

Moderate Decline in Violent Attacks Against Jews, But Attacks Are Becoming More Brutal

European Jews harbor increasingly "grave concerns for their security," annual TAU Kantor Center study reports.

TAU Announces Early-Stage Venture Fund to Invest in Student Innovation

TAU Ventures similar to funds at universities such as MIT, UC Berkeley and Stanford.

How Advanced Nanotechnology Can Improve Cancer Care

TAU, Harvard University researchers discuss untapped potential of targeted nanocarriers to revolutionize cancer therapy.

Antidepressants May Prevent Hospitalization Relapses in Bipolar Depression Patients

Study finds apparent benefits of addition of adjunctive antidepressants to mood stabilizers, TAU researchers say.

Koret Foundation Funds $10 Million Collaborative Initiative between TAU, Stanford University, and UC Berkeley

Grant designed to advance breakthroughs in medical and information technology.

Eastern Mediterranean Summer Will be Two Months Longer by End of 21st Century

Climate changes will cut winter in the region by half, TAU researchers say.

Having a Sibling Makes You More Empathetic, Study Finds

Younger and older siblings uniquely contribute to each other's development of empathy, TAU researchers say.

Non-invasive Brain Stimulation Improves Crucial Gait Impairment of Parkinson's Disease Patients

Transcranial direct current therapy positively impacts mobility and executive functions, TAU researchers say.

Search for First Stars Uncovers "Dark Matter"

Discovery offers first direct proof that dark matter exists and that it is made up of low-mass particles, TAU researcher says.

Scientists Discover Critical Molecular Biomarkers of Preeclampsia

Small non-coding RNAs may be used to devise a diagnostic blood test for pregnant women, TAU researchers say.

contentSecondary
c

© 2018 American Friends of Tel Aviv University
39 Broadway, Suite 1510 | New York, NY 10006 | 212.742.9070 | info@aftau.org
Privacy policy | Tel Aviv University