Through The Sandglass

Flux

 
Aral Sea shrinks, central Asia

The Aral Sea, located in Kazakhstan and Uzbekistan in central Asia. Left: June 4, 1977. Center left: September 17, 1989. Center right: May 27, 2006. Right: June 3, 2009. Once one of the largest inland bodies of salty water in the world and the second largest sea in Asia — 70,000 square kilometers or 27,000 square miles in area — the Aral Sea has shrunk dramatically over the last 30 years. One of the main reasons is crop irrigation: water has been drawn off from the rivers that kept the Aral Sea filled. As the sea has shrunk, the local climate has become harsher, there have been contaminated dust storms, and drinking water and the local fishing industry have been lost. By the late 2000s, the Aral Sea had lost four fifths of its water volume.

Images taken by the Multispectral Scanner onboard Landsat 1, the Thematic Mapper sensor onboard Landsat 5, and the Enhanced Thematic Mapper Plus onboard Landsat 7. Source: USGS Landsat Missions Gallery, "The Vanishing Aral Sea," U.S. Department of the Interior / U.S. Geological Survey and Encyclopaedia Britannica Online.

I just came across another extraordinary internet resource courtesy of NASA (whose captions and credits are quoted throughout). Titled “State of Flux – Images of Change,” it currently contains close to two hundred images of changes to the surface of our planet over the last few decades – it makes for mesmerising browsing. It comes under “climate.nasa.gov” but it’s by no means only about climate change – it chronicles other natural processes together with the – often depressing – footprints of our species. I found the site through a Scientific American blog piece titled “Views from Space show a Fragile Earth.” I must admit that I find this a strange title, an example of the emotional use of the word “fragile". This planet has been around, perfectly successfully and robustly, for 4.5 billion years – fragile it ain’t. The fragility of our own precarious and short-lived perch on the planet is another thing – and, in reality, what is being referred to by the adjective. But I am not setting up my soap-box here – the point is to celebrate the technology, and the access to it, that NASA offers. And yes, celebrate – we may, as many of these images provocatively show, be screwing around with the current nano-frame of the planet’s biopic, but at least we can’t hide that fact.

The following images are simply a personal selection after an initial browse, starting with the classic at the head of this post; further comment is hardly necessary.

 

River changes, China

The Yellow River Delta in China. Left: 2001. Right: 2009. The Yellow River is the second-longest river in China, and the sixth-longest in the world. It has been the cradle of Chinese civilization; but frequent devastating floods have also earned it the name of "China's Sorrow." Historical maps tell us that the river has undergone many dramatic changes in its course. Currently, the Yellow River ends in the Bohai Sea, yet its eastern terminus continues to oscillate from points north and south of the Shandong Peninsula. These images show the changes.

Images taken by NASA's Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument. Caption adapted from the ASTER gallery. Courtesy of NASA/GSFC/METI/ERSDAC/JAROS and the U.S./Japan ASTER Science Team.

 Agricultural growth, Egypt

Dakhla Oasis, Egypt. Left: January 4, 1986. Right: January 14, 2010. Dakhla Oasis lies 300 kilometers (190 miles) west of the Nile. It is surrounded by the driest of desert landscapes, but beneath it lies the southern edge of the Post Nubian Aquifer. Use of water drawn from deep wells in the aquifer has increased tenfold since 1960, with a corresponding growth in agriculture. But some studies suggest that the planned rate of extraction is unsustainable and will lead to local depressions in the water table, making the precious liquid more and more expensive to access.

Source: United Nations Environment Programme (UNEP). From Africa Water Atlas (2010); Division of Early Warning and Assessment (DEWA), UNEP, Nairobi, Kenya.

 Delta growth, Kenya

The Omo Delta, at the north end of Lake Turkana, a lake now located mainly in Kenya. Left: February 1, 1973. Right: January 24, 2005 to February 12, 2006. In 1973, the delta was contained entirely within the boundaries of Ethiopia. By 2005-2006, the southernmost point of the delta had moved roughly 12 kilometers (7 miles) to the south, and had crossed the Ethiopia-Kenya border. Reduced lake levels — from less rain, more diverted upstream water, and increased evaporation due to higher temperatures — are believed to be the primary cause, with an increase in sediment from agricultural activities also contributing. The expanded delta has provided new land for 20,000 Dassanech people, the area?s traditional inhabitants. But severe flooding in 2006 killed 100 of them and destroyed houses, crops and infrastructure.

Source: United Nations Environment Programme (UNEP). From Kenya Atlas of our Changing Environment (2009); Division of Early Warning and Assessment (DEWA), UNEP, Nairobi, Kenya.

 Lake shrinkage, Egypt

Toshka, Egypt. Left: September 13, 1984 to September 29, 1987. Center: August 23 to September 1, 2000. Right: March 21 to 28, 2010. In the mid-1990s, excess water was channeled from the Lake Nasser reservoir on the Nile River to the Toshka Depression in the Western Desert, creating a series of lakes. This "New Valley Project" was to relieve overcrowding within the Nile Valley and boost the economy. Despite soil poorly suited to irrigation, the area produced grapes, cantaloupes, tomatoes, cucumbers, citrus fruits and wheat. But Lake Nasser water levels fell after 1998 and flow to Toshka ceased in 2001. At the current rate of decline, the new lakes will be lost to evaporation within the next few years.

Source: United Nations Environment Programme (UNEP). From Africa Atlas of our Changing Environment (2008); Division of Early Warning and Assessment (DEWA) UNEP, Nairobi, Kenya.

Mining growth, Chile

The Atacama Desert, Chile. Left: November 23, 1987. Right: June 25, 2009. Population has doubled here over the past two decades due to explosive tourist development in the 1990s and a mining boom in the 1980s, when companies began to extract lithium and other minerals from the Atacama Salt Flats. Today the mining, tourism, domestic and agricultural sectors compete for the region's resources, and the main source of conflict is access to water. These images show the growth of mining operations from their beginning (white rectangle at lower right of the 1987 image) to a more recent level (purple and while rectangles in the 2009 image).

Source: United Nations Environment Programme (UNEP). From Latin America and the Caribbean Atlas of our Changing Environment (2010).

 Deforestation, Niger

Left: January 12, 1976. Right: February 2, 2007. Baban Rafi Forest is the most significant area of woodland in the Maradi Department of Niger, a west African country on the southern edge of the Sahara Desert. Located at the southern extreme of the Sahel, Baban Rafi has areas of both savannah and Sahelian vegetation. These pictures show the loss of a significant fraction of the natural landscape (darker green areas) of the forest to agriculture. Population in this region quadrupled during the 40 years leading up to the 2007 image, and intense demand for agricultural land has led to near-continuous use, with shortened or no fallow period to recover fertility. The remaining woodlands are overly exploited for fuel wood and non-wood forest products.

Source: United Nations Environment Programme (UNEP). From Africa Atlas of our Changing Environment (2008); Division of Early Warning and Assessment (DEWA), UNEP, Nairobi, Kenya.

And, finally, just a little local colour, since this is where I am:

 Urban growth, Indonesia

Jakarta, Indonesia. Left: 1976, with a population of six million. Middle: 1989, with nine million inhabitants. Right: 2004, with 13 million inhabitants. Jakarta was the last Hindu kingdom of West Java when the Portugese arrived in 1522. They were driven out 5 years later by Muslim saint and leader Sunan Gunungjati, who renamed the city Jayakarta. In the 17th century the Dutch captured the city, fortified and walled it, and renamed it Batavia. After World War II, Dutch colonial power came to an end when Soekarno declared the Republic of Indonesia. This time series of images shows the growth of the city over the past few decades; vegetation is rendered in red and urban areas shown in blue-grey.

1976 image acquired by the Landsat MSS scanner. 1989 image taken by the Landsat Thematic Mapper. 2004 picture captured by ASTER. Credit: NASA/GSFC/METI/ERSDAC/JAROS and the U.S./Japan ASTER Science Team. Caption adapted from the ASTER gallery.

Can we please not blow up coral reefs?

BEFORE: A Pinnate batfish swimming among other fish in Tatawa Besar in the waters of Komodo islands, Indonesia. AFTER: damaged coral reefs in the water of Tatawa Besar, Komodo islands, Indonesia. [Robert Delfs/Michael W. Ishak]

I admire corals – not only for their beauty, diversity, and the communities they harbour, but also for their fortitude. Notwithstanding our (justified) concern over the future of coral reefs today, they are extremely ancient critters and have survived for hundreds of millions of years through thick and thin. And when you consider the number of mass extinctions that have occurred in our planet’s turbulent history, those are extreme thicks and very thins.

Let’s face it, corals represent yet another example of things about which what we do know is but a fraction of what we don’t – see, for example, recent revelations on their survival skills. It’s only a few months since I had the pleasure of visiting parts of eastern Indonesia and, amongst the many memories, snorkelling around the glorious coral reefs of the Komodo Islands ranks right up there:

 
So, you can perhaps imagine my horror when recently, in the Jakarta Globe, courtesy of Associated Press, I saw the image at the head of this post and read the following story:

Fishermen Blast Premier Dive Sites Off Indonesia
Jacob Herin | April 20, 2012

Komodo Island, Indonesia. Coral gardens that were among Asia’s most spectacular, teeming with colorful sea life just a few months ago, have been transformed into desolate gray moonscapes by fishermen who use explosives or cyanide to kill or stun their prey. Dive operators and conservationists say the government is not doing enough to protect waters off the Komodo Islands in eastern Indonesia. They say enforcement declined greatly following the exit of a US-based conservation group that helped fight destructive fishing practices. Local officials disagree, pointing to dozens of arrests and several deadly gunbattles with suspects.

Michael Ishak, a scuba instructor and professional underwater photographer who has made hundreds of trips to the area, said he’s seen more illegal fishermen than ever this year. The pictures, he said, speak for themselves.
When Ishak returned last month to one of his favorite spots, Tatawa Besar, known for its colorful clouds of damselfish, basslets and hawksbill sea turtles, he found that a 200-square-meter reef had been obliterated. “At first I thought, ‘This can’t be right. I must have jumped in the wrong place,’” he said, adding he swam back and forth to make sure he hadn’t made a mistake. “But it was true. All the hard coral had just been blasted, ripped off, turned upside down. Some of it was still alive. I’ve never seen anything like it.”

The site is among several to have been hit inside Komodo National Park, a 500,000-acre reserve and U.N. World Heritage Site that spans several dusty, tan-colored volcanic islands and is most famous for its Komodo dragons — the world’s largest lizards. Its remote and hard-to-reach waters, bursting with fluorescent reds and yellows, contain staggering levels of diversity, from iridescent corals and octopuses with lime-green banded eyes to black-and-blue sea snakes.
They are supposed to be protected, but fishermen are drawn there by locally popular fish like fusiliers and high-value export species like groupers and snappers. Fishermen can be seen in small wooden boats, some using traditional nets or lines. Others have been captured on video blasting sites with “bombs” — fertilizer and kerosene mixed in beer bottles. Breathing through tubes connected to air compressors at the surface, young men plunge to the bottom and use squeeze bottles to squirt cyanide into the coral to stun and capture fish. Dive operators are increasingly seeing dead fish on the sea floor or floating on the surface.

“The biggest problem is that fishermen seem to be free to come into Komodo, completely ignoring the zoning and resource use regulations,” said Jos Pet, a fisheries scientist who has worked with numerous marine conservation groups in the area in recent years. He said they are “quite simply fishing empty this World Heritage Site.”

Sustyo Iriyono, the head of the park, said problems are being exaggerated and denied claims of lax enforcement. “It’s only part of the black campaigns against us by those who are hurt by our rules and orders,” he said without elaborating. He said rangers have arrested more than 60 fishermen over the past two years, including a group of young men captured last month after they were seen bombing waters off Banda island in the western part of the park. One of the suspects was shot and killed after the fishermen tried to escape by throwing fish bombs at the rangers, Iriyono said. Three others, including a 13-year-old, were slightly injured.

“You see?” said Iriyono. “No one can say I’m not acting firmly against those who are destroying the dive spots!”
He added that the park is one of the few places where fish bombing is monitored with any regularity in Indonesia, a Southeast Asian nation of more than 17,000 islands.

Divers, however, say enforcement has dropped dramatically since 2010, when the government reclaimed sole control of operations. For two decades before that, The Nature Conservancy, a U.S.-based nonprofit, had helped the government confront destructive fishing practices there. “No-take zones” were created, protecting spawning areas, and coastal areas also were put off limits. Patrols using park rangers, navy personnel and local police were key to enforcement.
In 2005, the government gave a 30-year permit to Putri Naga Komodo, a nonprofit joint venture company partially funded by The Nature Conservancy and the World Bank to operate tourist facilities in hopes of eventually making the park financially self-sustaining. Entrance and conservation fees — just a few dollars at the time — went up several tenfold for foreign tourists. With around 30,000 local and international visitors annually at the time, that would have given the park a budget of well over $1 million, but outraged government officials demanded that the funds go directly into the state budget. The deal collapsed in 2010, when Putri Naga Komodo’s permit was yanked. “They had no right to directly collect the entrance fees from the tourists,” said Novianto Bambang, a Forestry Ministry official.

Dive operators and underwater photographers have asked The Nature Conservancy and similar organizations like WWF Indonesia, to return to Komodo and help with conservation efforts there. Nature Conservancy representative Arwandridja Rukma did not address that possibility, saying only that the organization operates in Indonesia upon the invitation of the government.

Yes, this is horrifying: blowing up coral reefs or injecting them with cyanide is utter lunacy. But, as always, it’s not a simple issue. Unregulated and chaotic fishing have depleted natural stocks, and, regardless of what proportion of explosive mayhem is perpetrated by outsiders as opposed to locals, the fact is that the inhabitants of the Komodo islands, if not actually poverty-stricken, live very lean lives. These are some of our photos from the town of Komodo, the largest concentration of the population. These people have to live, and fishing is their main – virtually only – means of doing so. These kids deserve food, an education, a life.

After I read this piece, by yet another twist of serendipity, I received an email from Richard Bready. Richard is a frequent commenter on this blog, always adding a fascinating, and often provocative, dimension to the posts - and he is, so far, my only guest poet. It seems that, from the post on the European sand belt, he had been following a trail of links on the subject of geoconservation, and come across the site of Ashoka Changemakers – whose purpose is to create “opportunities for organizations, corporations, and individuals to drive meaningful and measurable social change.” They are supported by, amongst others, the Rockefeller Foundation and the Bill and Melinda Gates Foundation. Never having come across this initiative, I followed up, specifically, as Richard directed me, on their coastal program, and their “Geotourism Challenge 2010: Places on the Edge - Saving Coastal and Freshwater Destinations.” Now this competition has been supported by the National Geographic, the Inter-American Development Bank, and the latter’s Multilateral Investment Fund, and there is an understandable focus on Central America. But what fascinated me – and is of great relevance to the topic of this post – were two of the three winning initiatives:

1. Coral Gardens - Living Reefs

Reefs provide food and income for coastal communities and are a foundation of tourism, producing white sandy beaches and protecting shorelines. My idea has been to actively involve communities and the tourism industry in planting and caring for corals, with the dive industry trained to care for dive sites, and with resorts taking on trained "coral gardeners". Guests can also become involved and learn about reefs while they help plant corals and garden the reefs, giving something back to the destination and to the planet.

Go to the full description to read the details – this arises directly from the passion of an individual.

Then, there was this winner – deeply relevant to Komodo, and again the idea of an innovative individual:

2. Development of economic partnerships between artisanal fisher folk and tourism operators

Project will create economic partnerships/opportunities between artisanal fisher folk and the tourism sector by constructing a locally-supported fisheries co-op for certified, sustainably caught products and direct marketing strategy with local hotels/restaurants. Project will construct a marine research center that contributes to responsible tourism development/heritage protection by promoting local SMEs.

It struck me that these projects address exactly the issues that the reefs and the inhabitants of the Komodo Islands are facing – and that support for them by Ashoka Changemakers is admirable. The concept of translating these ideas into an Indonesian context is, as the article above so depressingly shows, a huge challenge. But Komodo is a National Park, and has been a World Heritage Site since 1991. If anywhere fits the definition of an “ecotourism destination,” and a prime candidate for geoconservation and biodiversity preservation, Komodo is it. But people live there and must be active participants in - and beneficiaries of - any progress. It may be difficult, but we can’t accept that it’s impossible, and surely somewhere there are people with the vision, the passion, and the expertise to make something like the initiatives described above actually work in Komodo. Please.

 

Guest post: a gallery of sand photographers' styles

 
Kurt Meyer writes:

SHOOTING SAND

For the last 15 years, on and off, I have been collecting sand. The “off” times resulted from not having an answer to the question, ‘what do I do with all of this sand?’ I have tried various methods of displaying my sands as you can see below. Two-ounce bottles with overhead lighting being the best. 

But the only people who could regularly view the display were my wife, the neighbors, some family and my dog, Zena, and she could care less. In fact, anything that draws attention away from her is not well tolerated.

Things got interesting again, however, when I decided to try my hand at getting pictures of my sands. At first, I tried a digital microscope and although it turned out to be an interesting exercise, the quality just wasn’t there. The edges, for example, are usually blurry, the definition is often lacking and the color is rarely true. These problems would even be too much for a Photoshop package. You can, however, get a good idea of what is lurking in your sand sample at 20x, as in this image of sand from Fintragh beach, but it is not suitable for framing.

Today I still use the digital microscope but only for screening sand samples. It is pretty good at predicting which sands will be “photogenic.”

My first foray into serious sand macrophotography began with my purchase of a used Nikon D70. The following picture was taken with that camera body and a 60mm 1:1 lens. Even though the sensor is only a 6.1MP it still provides a pretty good image. This photo is of one of the famous green sand beaches in Hawaii, Pocket Beach to be exact. The olivine, lava and coral make a striking image [at the head of this post - MW]. 

At any rate, this new photographic endeavor answered the big question, ‘what do I do with all of this sand?’ Answer, SHOOT IT.

There are a number of photographers who do outstanding sand photography. I would like to showcase several of them. This is, by no means, an exhaustive list. This only reflects the photographers that have posted images on my website, Tropics of Sand. I will attempt to compare and contrast their styles. As you will see, the top photographers all have their own style. Over and above the camera equipment used, the thing that defines a photographer is their approach to getting the shot. All of the images that you will see below are unique to the photographer. I can tell a Heider photo from a Couette and a Sepp from a Kenney in the blink of an eye. I am sure that you will, too.

SAND PHOTOGRAPHERS

(click images to enlarge)

Leo Kenney: Large field, great clarity

Leo is a veteran of creating outstanding sand calendars and posters. He has a prodigious collection thanks to the fact that he has a legion of former students who dutifully send sands to him from their travels (cheater). Leo tends to zoom out a bit which produces a larger field than most. He uses a Canon 1-5x lens that allows him to get that clarity. Leo’s Picasa Web albums are here.

 
Clockwise from top left: Miller’s Point, Cape Town, South Africa; Monticello, Corsica; Jeffrey’s Bay, South Africa; Rye, New Hampshire. Center: Cap Lardier, France.

Siim Sepp: Great definition of full field shots and individual grains.

Siim also uses the Canon 1-5x lens although Siim does more close up work. He uses a full field for some of his photos but he also shows exploded views of individual grains of sand elements. Siim has a “how-to” on the mechanics of getting a sand photo on his website, Sand Atlas. On that site, he also provides geological information on sand composition that is very informative.

 
Clockwise from top left: Diamond Head, Hawaii; Sapphire crystals, Songe, Southern Tanzania; Zakynthos, Greece; Waddell Sea floor (-3500m), Antarctica (Globigerina forams, yellow circles);  Center: Glass Beach, Kaui, Hawaii.

 

Alexander Heider: Tight shots, great color.

Herr Heider gets excellent close ups of his sands without sacrificing detail. As you can see in this series of sands from Ireland he is able to keep detail at close range. He also agonizes over white balance which gives very exacting color to his images. His tight shots and true color make his photos stand out.

 
Clockwise from top left, an Irish selection: Ardmore, Waterford; Ventry Strand, Dingle Bay; Dooagh, Achill Island, Fanore, Galway Bay; Center: Fintragh Bay, Killybegs.

 

Alain Couette: Soft shots, great detail.

Alain will not reveal what he uses as a lighting source but whatever it is, it gives his photos a “soft” look and it is also rich in detail. Alain has numerous images on his website, Arénophile ou Psammophile? He has sand pix plus images of forams that are very interesting. Alain has a distinctive style that I would recognize anywhere.

 Clockwise from top left: Boracay Island, Angol, Philippines; Nusa Lembongan, Ceningan Island, Indonesia; Rio Grande do Norte, Fernando de Noronha Island, Brazil; Luzon island, Nasugbu, Philippines; Center: Sanur, Bali, Indonesia

 

Carla Lagendijk: Daylight shots, great variety and picture perfect color.

Carla is one of the pre-eminent sand photographers today. As you can see her shots are very rich in detail. This is not due to the lens but the fact she shoots her photos in daylight, the sun illuminating every nook and cranny which in turn provides outstanding definition. The other thing that separates Carla from the pack is her prodigious collection. She has sand from anywhere you can imagine which greatly increases the chances of having outstanding material to work with. Below are 4 shots that typify her style, and of course, no examination of Carla’s work would be complete without a sample of one of her “selections”. These are selected bits of coral, forams, shells, etc., from various sand samples. I hesitate to use more than one for the simple reason that they are too awesome. If you can look at these all day, why would you look at anything else?

 Clockwise from top left: Bahia de Samana, Dominican Republic; Myrdal, Vik, Iceland (olivine and obsidian); Al Bustan, Oman;  Brétignolles, France; Center: Enubuj Island, Kwajalein Atoll, Marshall Islands.

 

Kurt Meyer: Exploded views, contrasting backgrounds.

I now use a Nikon d1500 with the same 60mm lens. What I like to do with my photos is create an edge where heavy minerals or carbonate elements can be isolated from the main body of sand allowing for a better view of the individual grains. This has been dubbed the “black corner” technique. The 5100 has a 16.2 MP sensor that will enable you to enlarge photos without losing definition. Also, I use black or other colored glass as a background to provide contrast.

 
Clockwise from top left: Cape Point, South Africa; Dondra Beach, India; Mardakyan, Azerbaijan; Grand Ile, France; Center: Point Reef, Vanua Levu, Fiji.

 

You can see more photos by all of the above photographers on tropicsofsand.com. I would love to add more images this weekend but Zena has other ideas.

 

[All images reproduced with the photographer’s permission, composite formats by MW.

Kurt is based in Pennsylvania, and writes that while he has been photographing sand for the last three years, he has collected it for “15 odd years.” Nothing odd about that as far as I’m concerned, but perhaps those years were odd in other ways, and sand collecting represented an opportunity for normality. Interestingly, he enjoys diving for samples. Anyway, thanks Kurt for all the effort in putting this together – and thanks to all the arenophile photographers who contributed to this piece.]

Granular flow: the icon continues to surprise

Anyone who reads this blog (and/or the book) will know that I have developed a deep fascination with the bizarre behaviours of granular materials: sand, a seemingly simple material, does stuff that hundreds of leading physicists around the world just don’t understand. Listing links to articles on this blog that explore the wondrous diversity of granular research would be too lengthy a task – just put “granular” into the search box and have a browse; new developments (and new mysteries) arise on a regular basis, and recent work at MIT is a fine example (all reports of which are illustrated – as, naturally, is this one – by a sandglass).

Here’s the news release from MIT. I hope that you enjoy as much as I did, the idea of “a million applications” from listening to chattering sand grains, and resist, as I did, any comments on size mattering in the chattering. Oh, and please, please, be sure to actually follow the link above and watch the movie of the researcher, Ken Kamrin, and his very beautiful sandglass – it’s essentially a manifesto for this blog.

Shifting sands

New model predicts how sand and other granular materials flow.

Jennifer Chu, MIT News Office

Photo: Lucy Lindsey

April 6, 2012

Sand in an hourglass might seem simple and straightforward, but such granular materials are actually tricky to model. From far away, flowing sand resembles a liquid, streaming down the center of an hourglass like water from a faucet. But up close, one can make out individual grains that slide against each other, forming a mound at the base that holds its shape, much like a solid.  
Sand’s curious behavior — part fluid, part solid — has made it difficult for researchers to predict how it and other granular materials flow under various conditions. A precise model for granular flow would be particularly useful in optimizing processes such as pharmaceutical manufacturing and grain production, where tiny pills and grains pour through industrial chutes and silos in mass quantities. When they aren’t well-controlled, such large-scale flows can cause blockages that are costly and sometimes dangerous to clear.
Now Ken Kamrin of MIT’s Department of Mechanical Engineering has  come up with a model that predicts the flow of granular materials under a variety of conditions. The model improves on existing models by taking into account one important factor: how the size of a grain affects the entire flow. Kamrin and Georg Koval, assistant professor of civil engineering at the National Institute of Applied Sciences in Strasbourg, France, used the new model to predict sand flow in several configurations — including a chute and a circular trough — and found that the model’s predictions were a near-perfect match with actual results. A paper detailing the new model will appear in the journal Physical Review Letters.
“The basic equations governing water flow have been known for over a century,” says Kamrin, the Class of ’56 Career Development Assistant Professor of Mechanical Engineering. “There hasn’t been something similar for sand, where I can give you a cupful of sand, and tell you which equations will be necessary to predict how it will squish around if I squeeze the cup.”
Blurring the lines
Kamrin explains that developing a flow model — also known as a continuum model — essentially means “blurring out” individual grains or molecules. While a computer may be programmed to predict the behavior of every single molecule in, say, a cup of flowing water, Kamrin says this exercise would take years. Instead, researchers have developed continuum models. They imagine dividing the cup into a patchwork of tiny cubes of water, each cube small compared to the size of the entire flow environment, yet large enough to contain many molecules and molecular collisions. Researchers can perform basic lab experiments on a single cube of water, analyzing how the cube deforms under different stresses. To efficiently predict how water flows in the cup, they solve a differential equation that applies the behavior of a single cube to every cube in the cup’s grid.

Such models work well for fluids like water, which is easily divisible into particles that are almost infinitesimally small. However, grains of sand are much larger than water molecules — and Kamrin found that the size of an individual grain can significantly affect the accuracy of a continuum model.
For example, a model can precisely estimate how water molecules flow in a cup, mainly because the size of a molecule is so much smaller than the cup itself. For the same relative scale in the flow of sand grains, Kamrin says, the sand’s container would have to be the size of San Francisco.
Neighboring chatter
But why exactly does size matter? Kamrin reasons that when modeling water flow, molecules are so small that their effects stay within their respective cubes. As a result, a model that averages the behavior of every cube in a grid, and assumes each cube is a separate entity, gives a fairly accurate flow estimate. However, Kamrin says in granular flow, much larger grains such as sand can cause “bleed over” into neighboring cubes, creating cascade effects that are not accounted for in existing models.
“There’s more chatter between neighbors,” Kamrin says. “It’s like the basic mechanical properties of a cube of grains become influenced by the movement of neighboring cubes.”
Kamrin modified equations for an existing continuum model to factor in grain size, and tested his model on several configurations, including sand flowing through a chute and rotating in a circular trough. The new model not only predicted areas of fast-flowing grains, but also where grains would be slow moving, at the very edges of each configuration — areas traditional models assumed would be completely static. The new model’s predictions matched very closely with particle-by-particle simulations in the same configurations.
Lyderic Bocquet, a professor of physics at the University of Lyon in France, sees Kamrin’s results as a big step toward a granular flow model with “trustable, predictive power.”
“There have been huge efforts over the last years to propose laws to describe granular flows, with the ultimate aim of designing devices or processes involving granular
materials,” Bocquet says. “The generalization to a broader system was still lacking. This is where Ken’s model could make the connection.”
The model, run on a computer, can produce accurate flow fields in minutes, and could benefit engineers designing manufacturing processes for pharmaceuticals and agricultural products. For example, Kamrin says, engineers could test various shapes of chutes and troughs in the model to find a geometry that maximizes flow, or mitigates potentially dangerous wall pressure, before ever actually designing or building equipment to process granular materials.
Kamrin says understanding how granular materials flow could also help predict geological phenomena such as landslides and avalanches and help engineers come up with new ways to generate better traction in sand.
“Granular material is the second-most-handled material in industry, second only to water,” Kamrin says. “I’m convinced there are a million applications.”

 

Sunday sand: Ngobaran

 
Sand from perhaps the smallest “beach” that I have visited and sampled. One of the items on the varied agenda of a recent long weekend in Central Java (varied in the way that part of the world uniquely and fascinatingly offers) was an exploration of a few of the small beaches on Java’s south coast. My intention was to avoid the crowds at the large, popular, beaches (the day of the visit being Sunday) and find a couple of the small coves that nestle between the spectacular cliffs of that part of the coast. The first destination was Ngobaran – and it certainly fulfilled the criterion of a “small beach.” Dramatic and rugged limestone cliffs face the incoming waves of the Indian Ocean, and the constant kinetics of the place leave little opportunity for sand grains to gather. But, in a small area sheltered by massive boulders, a patch of coarse sand had accumulated:

And here it is, the usual mix of local ingredients, including many of the little spherical forams, so common in these parts and looking for all the world like natural ball-bearings:

In detail, the varied patterns and textures are endless:

 
And, as further geo-entertainment, the weathering of the limestone boulders produced a starkly rugged form of tafoni: 

And, as I watched the Indian Ocean waves roll in, I was inspired to play with the the high-speed burst function of my camera and experiment with catching the action – nothing to do directly with sand, so please excuse my self-indulgence:

 

Today's Mad Hatters - the toxic price of gold

 
The Mad Hatter was mad as a result of poisoning from the mercury used in curing felt. Today’s artisanal gold miners are poisoned by the mercury used to extract the precious metal. Perhaps 15% of gold production today still comes from the small-scale activities of more than 50 million people in seventy countries around the world (see http://www.artisanalgold.org/home). And one of those countries is Indonesia, where, as is commonly the case, the gold is mainly extracted from placer sands and gravels by the age-old process of panning. Gold panning may be back-breaking work, but the real health hazard comes with the mercury used to further purify the product: mercury attracts the gold, forming an amalgam, and the mercury is then burnt off to leave the gold behind: 

 
There are relatively simple and effective devices that can prevent the mercury vapour escaping into the air – and the bodies of the miners and all around them – but they remain the exception rather than the rule. I had not appreciated the extent of this problem and was recently horrified to read (and see the images from) the following piece in the Jakarta Globe:  

Indonesia's Poisonous River of Gold: The Mercury Dilemma
March 29, 2012

Esrum has always gone to the river near his house when he needs something for his family.
“Our ancestors always had two things to sustain them: the jungle and the river. The jungle provided us with our basic needs and the river with gold, so we could buy what we could not get from the jungle,” Esrum said.
For decades, villagers in Tumbang Anoi in Central Kalimantan have panned for gold in the Kahayan River, and for generations the system worked well. But at the end of the 20th century, a relatively cheap and efficient way of extracting gold was introduced that used mercury.
A deadly combination

Mercury binds particles of gold together, forming an amalgam of metals that miners are then able to burn to remove the extraneous mercury. The process works well, but what Esrum and his fellow small-scale miners did not know was that this deadly toxin can enter the air, water and ground, poisoning the fish they eat, the water they drink and the air they breathe.
Even in small quantities, mercury can cause severe health problems like miscarriages, brain damage, tremors, kidney, skin and eye problems and even death. These symptoms can appear quickly, or over a long period of time. Mercury is especially dangerous to young children and pregnant mothers, who can pass on the poison to the unborn child.
As background levels increase in the environment, more people, even outside of the mining community, are threatened.
The worst recorded case of mercury contamination was in Minamata, Japan, where thousands of people were poisoned by methylmercury as a result of eating fish. The mercury was released in the industrial wastewater of a Chisso Corporation chemical factory, taking place over decades from 1932 to 1968.
The mercury accumulated in sea life in Minamata Bay and the Shiranui Sea, and while human, cat, dog and pig deaths continued for some 30 years, the government and company did little to prevent the pollution. As of March 2001, 2,265 victims had been officially recognized — 1,784 of the victims have died ­— while more than 10,000 other related parties have received financial compensation from Chisso.
By 2004, Chisso had paid $86 million, and was also ordered to clean up the contamination. In 2010, a settlement was reached to compensate as-yet unverified victims.
“We want to prevent the Minamata incident from appearing here in Indonesia,” said Sumali Agrawal, head of the Mercury Project, part of a nonprofit foundation based in Central Kalimantan.
“But mercury contamination is already widespread in Kalimantan and Sulawesi, as well as other islands, including Java. Small-scale gold mining is by far the greatest cause of mercury emissions in Indonesia. Even in Bogor, near Jakarta, 17,000 kilograms of mercury are emitted by gold processors every year. In Central Kalimantan, over 50,000 kilograms are emitted into the environment each year in one location alone.”
The Mercury Project was implemented by Yayasan Tambuhak Sinta, a nonprofit foundation set up by Kalimantan Gold Corporation, a minerals exploration venture that supports sustainable mining practices. Its mercury remediation program receives support from the Blacksmith Institute, the United Nations Environmental Program and the US Environmental Protection Agency.

A way out
The foundation works with local miners and introduces recycling technology that reduces mercury emissions by up to 95 percent. But it’s not just the miners who need to understand the dangers of using mercury; the entire community must be made aware of the risks in order for real change to occur.
“I really didn’t understand how mercury could hurt my family,” said Nyai, who lives in the mining area. “My kids even played with it. We would burn the amalgam in the open. I never thought breathing the smoke could harm us.”
Getting mercury recycling equipment to gold miners and processors is just one way to help reduce the impact of mercury on the environment. Each of the cheap and simple retort devices supplied by YTS recovers mercury directly and immediately reduces the quantity that escapes into the environment.
In January 2007, YTS created a water-box condenser as a low-cost solution to prevent pollution from gold shops as part of efforts from the United Nations Industrial Development Organization and the Global Mercury Project. UNIDO provided these mercury recovery systems to 36 gold shops in a village in Katingan district. Their mercury-pollution program has since been extended with funding from the Blacksmith Institute, and now covers six districts in Central Kalimantan.
The water-box condenser traps mercury fumes inside a plastic box filled with water. Equipment distributed last year directly prevented 3,400 kilograms of mercury from being released into the air.
YTS is also working to introduce mercury-free methods such as gravity separation and direct smelting with borax. This method has been used successfully in the Philippines for decades but has not yet been implemented in other areas.
A 1967 law on mining practices prohibits small-scale mining except in designated community mining areas. However, the rising price of gold, decentralization, lack of natural resource management and unclear regulations have contributed to the rapid spread of mining with mercury across Indonesia over the last 15 years.
There is also a lack of alternative employment for many of the people in these new gold mining communities. In 2006, 570 mining hot spots were identified that involved 50,000 miners and 300,000 ancillary people who depended on small scale mining activities.
By 2010, more than 800 hot spots were found throughout the archipelago.

A global issue
Nearly a third of the world’s gold production comes from more than 15 million small scale miners, including one million child laborers. The mercury problem affects many developing countries in Latin America, Africa and Asia. In many countries, small-scale mining is an important driver of economic development, but one that brings unacceptable health and environmental consequences.
Experts from MercuryWatch estimate that small-scale mining releases at least 1,400 tons of mercury into the environment every year. For every kilogram of gold mined, at least three kilograms of mercury are released into the ecosystem.
The international effort to ban mercury has caused a sharp rise in the price, which is having a beneficial impact, limiting some of the worst practices such as pouring mercury into rock-crushers.
Indonesia is one of 140 countries that has agreed to outlaw the use and production of mercury by entering into a legally binding international treaty on the toxic liquid metal.
“Now, more than ever before, it is vital that artisanal miners are empowered to change their practices in order to prevent further mercury contamination of our environment,” Sumali said. “This will require a coordinated effort from all stakeholders in this sector, working hand in hand with the government and the global community.”
Yayasan Tambuhak Sinta
Jl. Badak VII No.2, Bukit Tunggal
Palangka Raya
Central Kalimantan
[email protected]
www.tambuhaksinta.com

So, our desire for bright, shiny, precious stuff provides a livelihood for tens of millions of people around the world – but, at the same time, poisons them. Nevertheless, there are solutions and these are being actively addressed by organisations on all scales, from the local YTS in Kalimantan, to the UN Development Programme. May they be successful. Let’s hope that toxicity can be eliminated, and, just as “blood diamonds” became part of our terminology, “dementia gold” becomes part of our consumer awareness.

 

[Images from the Artisanal Gold Council, the Jakarta Globe, and the Jakarta Post. For further excellent resources, see, for example, http://www.blacksmithinstitute.org/blog/?p=121, http://bario-neal.com/bn/blog/?p=1197, http://www.epa.gov/international/toxics/mercury/asgm.html, and http://www.msnbc.msn.com/id/28596948/ns/world_news-world_environment/t/mercury-gold-mining-poses-toxic-threat/]

Oh, and wasn’t I self-disciplined in making no commentary on the Tea Party?