Nav: Home

'Sudoku' X-Ray uncovers movements within opaque materials

November 30, 2018

When strolling along the beach, our footprints tell us that the sand under the surface must have moved but not precisely where or how. Similar movements occur in many other natural and man-made substances, such as snow, construction materials, pharmaceutical powders, and even cereals.

To examine these largely unknown granular movements, academics from the Sydney Centre in Geomechanics and Mining Materials (SciGEM) including Professor of Civil Engineering, Itai Einav and Postdoctoral Research Associate, Dr James Baker have developed a new X-ray method which allows scientists to see inside granular flows. Named X-ray rheography, or "writing flow", their approach gathers information using 3-point high-speed radiography, and then assembles this information by solving a Sudoku-style puzzle.

"Imagine coffee in grinders, rice in silos, and minerals on conveyors - for a long time we've known that the grains hidden within the bulk move, but until now we have not understood precisely how. Our X-ray rheography is the first physical method to resolve this," explained Professor Einav.

This breakthrough is the latest to arise from the team's "DynamiX" laboratory, a unique, custom-built facility that was established in 2015 to investigate flowing granular media. The laboratory consists of a large lead-lined X-ray room, with three movable source-detector pairs to allow interrogation of numerous different experiments, and an external control room.

The new X-ray rheography technique has the ability to form a three dimensional image of moving grains, which has helped the researchers better understand how particles flow and behave in various circumstances. In many examples they have found that granular media tends to flow in unique patterns and waves.

"Unlike fluids, we discovered that confined, three-dimensional steady granular flows arise through cycles of contraction and expansion, à la 'granular lungs'. Again, unlike fluids, we also found that grains tend to travel along parallel lines, even near curved boundaries.

Experimenting with various granular materials, the team also found that shape is an important factor in determining flow, for example elongated barley grains move faster than their spherical counterparts. In other situations, different types of grains may have a tendency to group together, or "segregate", much like when emptying a cereal box.

The researchers' findings can be applied to a number of industries, such as helping develop better silo solutions for edible grains, preventing wastage and spoilage in both farming and large scale food manufacturing, as well as more efficient transportation and storage of mining resources.

"Until now, understanding granular movements in opaque materials has long been a challenge for many industries such as engineering, science, mining and even agriculture," explained Dr James Baker.

"The potential benefits span many areas, whether it be in understanding the mixing of pharmaceutical powders or the efficient transport of food grains or construction materials."

Professor Einav hopes that his team's creative approach in using a game of logic to answer a long misunderstood scientific issue may help rethink other research approaches, "We have successfully applied a novel approach to an ongoing issue - so we must ask how other games can help us make further breakthroughs?"
-end-
The paper, X-ray rheography uncovers planar granular flows despite non-planar walls was co-written by Professor Itai Einav, Dr James Baker, Dr François Guillard and Dr Benjy Marks and was published in Nature Communications on November 30.

About the Sydney Centre in Geomechanics and Mining Materials

The Sydney Centre in Geomechanics and Mining Materials (SciGEM) within the School of Civil Engineering was established in 2013 to harness the outstanding pool of researchers with specialised skills and expertise in the field of geomechanics and geotechnical engineering.

The centre's objective is to remain world leaders in the research fields of geomechanics, geotechnical engineering and granular mechanics, whilst expanding into newer geo-environmental research issues such as soil contamination and bulk materials handling issues.

University of Sydney

Related Engineering Articles:

Engineering a new cancer detection tool
E. coli may have potentially harmful effects but scientists in Australia have discovered this bacterium produces a toxin which binds to an unusual sugar that is part of carbohydrate structures present on cells not usually produced by healthy cells.
Engineering heart valves for the many
The Wyss Institute for Biologically Inspired Engineering and the University of Zurich announced today a cross-institutional team effort to generate a functional heart valve replacement with the capacity for repair, regeneration, and growth.
Geosciences-inspired engineering
The Mackenzie Dike Swarm and the roughly 120 other known giant dike swarms located across the planet may also provide useful information about efficient extraction of oil and natural gas in today's modern world.
Engineering success
Academically strong, low-income would-be engineers get the boost they need to complete their undergraduate degrees.
HKU Engineering Professor Ron Hui named a Fellow by the UK Royal Academy of Engineering
Professor Ron Hui, Chair Professor of Power Electronics and Philip Wong Wilson Wong Professor of Electrical Engineering at the University of Hong Kong, has been named a Fellow by the Royal Academy of Engineering, UK, one of the most prestigious national academies.
Engineering a better biofuel
The often-maligned E. coli bacteria has powerhouse potential: in the lab, it has the ability to crank out fuels, pharmaceuticals and other useful products at a rapid rate.
Pascali honored for contributions to engineering education
Raresh Pascali, instructional associate professor in the Mechanical Engineering Technology Program at the University of Houston, has been named the 2016 recipient of the Ross Kastor Educator Award.
Scaling up tissue engineering
A team at the Wyss Institute for Biologically Inspired Engineering at Harvard University and the Harvard John A.
Engineering material magic
University of Utah engineers have discovered a new kind of 2-D semiconducting material for electronics that opens the door for much speedier computers and smartphones that also consume a lot less power.
Engineering academic elected a Fellow of the IEEE
A University of Bristol academic has been elected a Fellow of the world's largest and most prestigious professional association for the advancement of technology.

Related Engineering Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Changing The World
What does it take to change the world for the better? This hour, TED speakers explore ideas on activism—what motivates it, why it matters, and how each of us can make a difference. Guests include civil rights activist Ruby Sales, labor leader and civil rights activist Dolores Huerta, author Jeremy Heimans, "craftivist" Sarah Corbett, and designer and futurist Angela Oguntala.
Now Playing: Science for the People

#520 A Closer Look at Objectivism
This week we broach the topic of Objectivism. We'll be speaking with Keith Lockitch, senior fellow at the Ayn Rand Institute, about the philosophy of Objectivism as it's taught through Ayn Rand's writings. Then we'll speak with Denise Cummins, cognitive scientist, author and fellow at the Association for Psychological Science, about the impact of Objectivist ideology on society. Related links: This is what happens when you take Ayn Rand seriously Another Critic Who Doesn’t Care What Rand Thought or Why She Thought It, Only That She’s Wrong Quote is from "A Companion to Ayn Rand"