Through The Sandglass

Icons old and deep

 
Thanks to Walter for bringing to my attention this particularly resonant and compelling image from the recent coverage of the investigation of a dramatic shipwreck in the Gulf of Mexico.

Here’s part of the original report from NOAA:

NOAA, BOEM: Historic, 19th century shipwreck discovered in northern Gulf of Mexico

May 16, 2012

  While most of the ship's wood has long since disintegrated, copper that sheathed the hull beneath the waterline as a protection against marine-boring organisms remains, leaving a copper shell retaining the form of the ship. The copper has turned green due to oxidation and chemical processes over more than a century on the seafloor. Oxidized copper sheathing and possible draft marks are visible on the bow of the ship.(Credit: NOAA Okeanos Explorer Program.)

During a recent Gulf of Mexico expedition, NOAA, BOEM and partners discovered an historic wooden-hulled vessel which is believed to have sunk as long as 200 years ago. Scientists on board the NOAA Ship Okeanos Explorer used underwater robots with lights and high definition cameras to view remnants of the ship laden with anchors, navigational instruments, glass bottles, ceramic plates, cannons, and boxes of muskets.

Equipped with telepresence technology, Okeanos Explorer reached audiences around the world who participated in the expedition through live streaming Internet video. As members of the public ashore watched live video from the ocean bottom, they became “citizen explorers,” sharing in the discovery with maritime archaeologists, scientists and resource managers from a variety of federal, academic, and private organizations.

The NOAA-funded 56-day expedition that ended April 29 was exploring poorly known regions of the Gulf, mapping and imaging unknown or little-known features and habitats, developing and testing a method to measure the rate that gas rises from naturally-occurring seeps on the seafloor, and investigating potential shipwreck sites.

The shipwreck site was originally identified as an unknown sonar contact during a 2011 oil and gas survey for Shell Oil Company. The Department of Interior’s Bureau of Ocean Energy Management (BOEM) requested this and other potential shipwreck sites be investigated during NOAA’s Gulf of Mexico expedition. Surveys and archaeological assessments are required by BOEM to aid in its decision-making prior to issuing permits for bottom-disturbing activities related to oil and gas exploration and development.

“Artifacts in and around the wreck and the hull’s copper sheathing may date the vessel to the early to mid-19th century,” said Jack Irion, Ph.D., a maritime archaeologist with BOEM. “Some of the more datable objects include what appears to be a type of ceramic plate that was popular between 1800 and 1830, and a wide variety of glass bottles. A rare ship’s stove on the site is one of only a handful of surviving examples in the world and the second one found on a shipwreck in the Gulf of Mexico.”

Significant historical events occurring in the regions around the Gulf of Mexico during this time include the War of 1812, events leading to the Texas Revolution, and the Mexican-American War, he said.

“Shipwrecks help to fill in some of the unwritten pages of history,” said Frank Cantelas, a maritime archaeologist with NOAA’s Office of Ocean Exploration and Research. “We explored four shipwrecks during this expedition and I believe this wreck was by far the most interesting and historic. The site is nearly 200 miles off the Gulf coast in over 4,000 feet of water in a relatively unexplored area.”

The news has been reported widely, these extracts being from CBS News and the Associated Press:

"When we saw it we were all just astonished because it was beautifully preserved, and by that I mean for a 200-year-old shipwreck," said Jack Irion, maritime archaeologist with the Department of the Interior's Bureau of Ocean Energy Management in New Orleans… Among the wreckage were "a rather astonishing number of bottles," particularly square gin bottles known as case bottles, as well as wine bottles, Irion said. There were many ceramic cups, plates and bowls that didn't appear to be cargo. Some were green shell-edged pearl ware, a British import popular in the United States between 1800 and 1830. The ship's kitchen stove was found intact. "Very few shipwrecks have been found that still have the stove intact," Irion said. "You can very clearly see the features of the stove. It's in rather good shape." Also discovered were an anchor, cannons and muskets. Irion said researchers have not yet determined whether it was a merchant, military or pirate ship… The wreckage can also give insight to the lives of the crew, where they had been, where they were going and their role in the economy and world history. "It's as if we get a glimpse into what their lives were like, like a time capsule," Irion said.

All kinds of fascinating stuff, but I can’t understand why no mention of the sandglasses lying in the sand…

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.”

 

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
tambuhaksinta@gmail.com
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?

"Our own little bridge to nowhere"

As someone who tries to write regularly on diverse topics that not only interest me, but, hopefully, interest others, an occasional gift horse appears, or, to mix metaphors, a whopping great drum that is just asking to be beaten – again. There have been a few drums over the course of this blog, but none appearing so regularly as the one representing the issues of coastal management – a veritable timpano, together with seductively large drumsticks just begging to be taken up and used. And here’s that drum again. 

 
Last year, I wrote a short piece on the aftermath of Hurricane Irene on the barrier islands of the Outer Banks. By the time the storm hit Hatteras, it was no longer a major hurricane, but nevertheless, it played the game that storms and barrier islands have always enjoyed, dramatically re-designing the geography by creating new inlets that sliced and diced the thin strips of sand. Highway 12, the “lifeline” of the Outer Banks, was cut in two places. As described in this New York Times article (titled “A North Carolina Lifeline Built on Shifting Sands” and spotted by an alert reader, Stephan Bossert), a temporary bridge was quickly constructed and the highway was back in operation in October last year. But “temporary” just goes with the territory in the saga of a barrier island, and the bridge is already in trouble:

By January, engineers were reinforcing its southern approach with sandbags and rock trucked in from the mainland, in hopes of keeping the road open until a more permanent fix could be designed and built.

And, unfortunately, this is only one of a series of problems that afflict this shape-shifting chain of islands:

Last summer, the state confronted what engineers called “advanced deterioration” of the Herbert C. Bonner Bridge, which carries the highway from Nags Head to the Pea Island National Wildlife Refuge, on the north end of Hatteras Island… The state opted for a replacement bridge that will run right alongside the existing span; planning is under way.

Now I have cited on numerous occasions in this blog, the wisdom of Robert S. Young, a coastal geologist who is head of the Program for the Study of Developed Shorelines at Western Carolina University, in particular during the Gulf Coast berms fiasco. Young calls the replacement bridge project “our own little bridge to nowhere.”

They can engineer that bridge so well that it can withstand a Category 3 or 4 hurricane,” Dr. Young said in a telephone interview. “The barrier island it is connected to cannot."

And there is the nail (or the drum) hit firmly on the head. As the NYT article notes:

Barrier islands like the Outer Banks are inherently unstable. Waves typically strike these islands at a slight angle, creating currents that pick up sand and carry it along the coast. The wave energy along the Outer Banks is unusually strong; by some estimates 700,000 cubic yards of sand, enough to fill 70,000 average-size dump trucks, moves along that stretch of coast every year.

At the new bridge, evidence of this process appeared even on opening day, in the form of long-necked black water birds called cormorants perching on a spit of sand that had formed near the north side of the bridge. That spit had not been there a few days before, said Pablo Hernandez, the transportation department engineer who managed the bridge work.

“It’s very difficult,” he said. “This whole thing has been constantly moving and shifting.”

As he spoke, waves were already starting to cut sharply into the sand at the bridge’s southern flank, an area the engineers later reinforced.

and

Already, Highway 12 floods repeatedly and is often cut by storms. Maintaining it “is totally a lost cause,” said Stanley R. Riggs, a coastal scientist at East Carolina University who is an author of a new book, “The Battle for North Carolina’s Coast,” which describes in depressing detail the difficulties of keeping the road open. “It will bankrupt the state,” he said.

Now that book by Riggs and his colleagues is clearly one to add to the top of the list, another rational discussion of the science – what we know and what we don’t know – in managing complex coastal systems. But, as has been the case on so many occasions and in so many different places, the science is ignored and its proponents branded as pessimists in the face of vested commercial and residential interests. The loudest beating of the drum comes from lobbying groups who have the clout that mere academics do not. In this particular case, it’s the likes of NC20 and The Land Alliance of North Carolina. “Better Science for Better Policy” is the rallying cry of the latter group, and one of the former’s goals (mixed in with links to alternative views of man’s effect on climate change) is “To advocate for science based environmental rulemaking in all areas of environmental regulation.” These groups play the tired old game of “the science isn’t conclusive” to audiences who are not equipped to judge whether this is reasonable or even relevant. It’s a tired old game, but it’s an axe that grinds loudly (along with the timpani). These groups trumpet (is there no end to the orchestral references?) their major victory of persuading the North Carolina Coastal Resources Commission to emasculate the section in their recent planning document that addressed issues of sea-level rise.

Sections of the book by Stanley Riggs et al. can be viewed online, and the first chapter, “Why is there a coastal conflict?” concludes with the following statement – one for which the biggest drum, the loudest axe, and the most brazen trumpet should be made available and listened to:

Our vision for the future of coastal North Carolina now requires the wisdom of policymakers and the concerted efforts of the public, coastal businesses, government agencies, and politicians to integrate science into management, informed by an awareness that our changing coastal system has natural limits to growth and development. If we are sufficiently farsighted, we can sustain a viable coastal economy in relation to the processes of change and, in doing so, preserve the natural resources on which that economy is based. As a result, more potential economic benefits would arise in the future than the current approach to coastal development could provide.

What are our alternatives? We must understand how the coastal system works and accept that reality. We must consider the challenges of coastal change to be opportunities. We can then determine the best ways to maintain our coastal economy and new ways to make a living on the coast. We should embrace the historical culture and the wild remoteness of the barrier islands and parlay those attributes into economic advantage.

Chinese New Year and an Indonesian Sand Artist

A few weeks ago, Chinese New Year was being celebrated. In Indonesia it’s known as “Imlek,” and Jakarta certainly celebrated. For us, this was truly remarkable since, when we were last here 20 years ago, you still had to vouch on the immigration form that you not only were not carrying explosives, but that you had nothing with Chinese writing on it. Some things have improved in the intervening years.

We are now in the Year of the Dragon – the Water Dragon to be precise; I was born, with no choice, in the Year of the Dog – but at least it was a Fire Dog. Dragons were everywhere for Imlek – especially in commercial locations where they might induce a level of exuberance that would lead to purchasing stuff. The absurdly (and, given the overall social context, disturbingly) ritzy mall in our building complex was no exception. And, along with the dragons, came events. My eye was caught by a small item on the poster announcing these, between “Fiddle with 2 Strings,” and the “Dainty Lotus Dance” - “Grains of Sand.” Mystified, I hurried along one lunchtime, and watched a performance by “Indonesia’s only sand artist.” This is the art  of telling stories via continually changing hand-sculpted images in sand on an overhead projector. One of its celebrity proponents is Kseniya Simonova, who won “Ukraine’s Got Talent” with her work a couple of years ago. It may not be “great art” in the traditional sense, but it’s compelling to watch, it’s highly creative and requires impressive skills – I certainly couldn’t do it.

 

The Indonesian artist, “Denny Darko,” performed wearing a blindfold, and his story, topically, was “The Legend of Lotus Flower and the Dragon King.” You find your attention switching from the artist to the screen, watching his hands moving, pouring, scattering, and sculpting the sand, the grand sweeps dramatic, the small details meticulous and mysterious, images appearing and dissolving. And one of the compelling aspects is the expectation – a scene begins to take shape, but you have no idea what exactly it will be, until a detail begins to emerge and all is revealed. No, it may not be “great art,” but it’s really impressive, fascinating to watch, and a great way of visually telling a story.

A couple of images and a short movie:

 

Critters versus Sand, Round 2: awesome Androctonus

 
This time, imagine that you're a scorpion, a fattail scorpion to be precise (sorry, but I never said anything about this role-playing being about cuddly and loveable, handsome or cute, but it’s often critters from the less celebrated realms of the animal kingdom that demonstrate the most remarkable skills). You are going about your desert business, scurrying across the sand in search of something to slaughter, when a sandstorm blows up. What should you do? Quickly seek shelter, bury yourself in the sand? Absolutely no need if you’re Androctonus australis, because you, unlike much of the world’s mechanised military, have developed an extraordinarily clever resistance to windblown sand. Blasting that can frost a windshield, clog up a filter, render many moving parts unmoving, never mind erode rocks, simply blows by you – sand off a scorpion’s back.

The yellow fattail scorpion (Androctonus australis) is an unpleasant creature, growing up to 10 cms in length, and capable of an envenomation that is dangerously and mortally toxic. But on their backs, they carry a bionic shield against sand abrasion, an exoskeleton that has bumps and grooves, the design of which cunningly deflects flying sand grains (illustration above, right).

All this has been recently revealed by a group of researchers at the Key Laboratory of Bionic Engineering, Jilin University, China, and published by the American Chemical Society. Erosion Resistance of Bionic Functional Surfaces Inspired from Desert Scorpions describes how these scorpions use microtextures to achieve erosion resistance, and how the researchers used Computational Fluid Dynamics to understand how these patterns work. The results have significant implications for the mechanised military (not to mention, perhaps, Toyota and Land Rover). Here’s the account from Science Daily:

Taking inspiration from the yellow fattail scorpion, which uses a bionic shield to protect itself against scratches from desert sandstorms, scientists have developed a new way to protect the moving parts of machinery from wear and tear.

A report on the research appears in ACS' journal Langmuir.

Zhiwu Han, Junqiu Zhang, Wen Li and colleagues explain that "solid particle erosion" is one of the important reasons for material damage or equipment failure. It causes millions of dollars of damage each year to helicopter rotors, rocket motor nozzles, turbine blades, pipes and other mechanical parts. The damage occurs when particles of dirt, grit and other hard material in the air, water or other fluids strike the surfaces of those parts. Filters can help remove the particles but must be replaced or cleaned, while harder, erosion-resistant materials cost more to develop and make. In an effort to develop better erosion-resistant surfaces, Han and Li's group sought the secrets of the yellow fattail scorpion for the first time. The scorpion evolved to survive the abrasive power of harsh sandstorms.

They studied the bumps and grooves on the scorpions' backs, scanning the creatures with a 3-D laser device and developing a computer program that modeled the flow of sand-laden air over the scorpions. The team used the model in computer simulations to develop actual patterned surfaces to test which patterns perform best. At the same time, the erosion tests were conducted in the simple erosion wind tunnel for groove surface bionic samples at various impact conditions. Their results showed that a series of small grooves at a 30-degree angle to the flowing gas or liquid give steel surfaces the best protection from erosion.

So just orient yourself appropriately to the wind, and scuttle off on your evil way.

 

[See also the Physorg.com report. Oh, and Richard, “envenomation” was especially for you…]

They wept like anything to see such quantities of sand

 
The owners of otherwise delightful beachfront homes on the Oregon Coast near Waldport, Oregon, must feel like responding as the Walrus and the Carpenter did – except that their situation is much, much, more serious.

Many thanks to Howard Allen for spotting this recent report by Dan McShane on his “Reading the Washington Landscape” blog. It shows homes literally half-buried in sand and such disastrous events were reported last year by KCBY in Coos Bend, from where the images above were taken. A winter storm had “left sand piled up to the roof level of some homes in Waldport.” But can we disengage from the human component of the equation and observe this simply as another example of naturally dynamic coastal geology? Probably not.

Inevitably on this blog, I have commented a number of times on issues of coastal processes, our attempts (generally futile) to “manage” them, and on the feedback between nature and human activities; “nourish or retreat?” was a relatively recent example, “Coastal change and saving sand - the state of the art” looked at meticulous work on this topic by the USGS and others, then there was the impact of Hurricane Irene, and a discussion of sediment budgets (and I have omitted my series of fulminations on the lunatic schemes for the Gulf Coast following the Macondo catastrophe). But I was reminded also of the publication of Orrin Pilkey’s book on beaches in August last year, when I wrote as follows:

I have referred several times in the past to Orrin H. Pilkey, James B. Duke Professor Emeritus of Geology at Duke  University. Now, together with colleagues from the US and Northern Ireland, he has published what promises to be an informative, entertaining, and provocative read - The World's Beaches: A Global Guide to the Science of the Shoreline. I haven't, of course, got my hands on a copy yet, but a review in the New York Times simply confirms that anything by Pilkey is required reading. The review is titled "Shorelines, Sandy or Otherwise, That May Not Last." The conclusion echoes the issue that I posted on a couple of months ago:

But, the authors conclude, unless society chooses beaches over buildings the result will be a world in which parks like the National Seashores retain natural beaches, but beach resorts elsewhere are “heavily walled and beachless.” Rising seas will make sand-pumping operations “untenable,” they predict, and tourists will amuse themselves by “promenading on top of a seawall” — already the principal activity in too many coastal resorts.
If they are right, by then the beaches this book describes will be a nostalgic memory.

The book is published by the University of California Press, to whom I will ever be grateful for publishing mine, and the New York Times review is by Cornelia Dean, whose own book, "Against the Tide: the Battle for America's Beaches," also falls into the required reading category.

Now the hazards of owning a beachfront home in Waldport Oregon remind us dramatically that it’s not simply shifting shorelines that are impacted by human activity (and, regardless, represent an entirely natural threat). Invariably, when beachfronts are developed, the first things to go are the dunes (after all, they obstruct the view). But dunes are an integral and vital part of the shoreline system – remove them and that system is destabilised. Once destabilised, it is then vulnerable (as are properties) to windblown movement of sand on a massive scale.

Being, as ever, curious, I went online to try to find more on coastal dynamics at Waldport. I’m sure there are more recent studies, but this piece of work from 1975 by the Oregon Department of Geology and Mineral Industries proved fascinating and more than sufficient: "Recent Shoreline Changes of the Alsea Sandspit, Lincoln County, Oregon." Written by James Stembridge of the Department of Geography at the University of Oregon, it provides some historic portents.  

The buried houses are built on a shape-shifting promontory of sand, the Alsea Sandspit, and here is a photo of it from 1975 (compare with the Google Earth images below):

 
And here, from that publication, is a compelling map of changes to the spit over the period from 1939 to 1975:

I have extracted some informative passages from the publication (remember, this was 37 years ago – before anything like the scale of today’s development):

Erosion of coastal sandspits has been a recognized hazard in Oregon since the demise of the resort community of Bayocean near Tillamook, which was slowly eliminated by the sea beginning in the late 1920's. Currently, the sandspit at Siletz Bay is undergoing severe erosion which is critically endangering structures along a three-mile beach front. Partially as a result of these experiences with eroding sandspits, some planning agencies, such as the Oregon Coastal Conservation and Development Commission, have considered limiting the construction of housing units on sandspits.

This study is a preliminary analysis of a third Oregon spit, the Alsea near Waldport, with respect to recent shoreline changes, human modifications, and potential impact on current and future settlement.

Unlike the Tillamook and Si letz spits, the Alsea sandspit is presently accreting at a rate as great as 10 feet per year at its southwest margin. Erosion at a rate of as much as 2 feet per year is occurring on the bay side of the spit, however, as well as along the northwestern margins of the spit, where the underlying terrace of semi-consolidated Pleistocene dune deposits is exposed to ocean wave action.

...... This main foredune is at least partially bulldozed into shape and rests at a position of up to 100 feet inland of its 1939 location. It is well stabilized with European beach grass (Ammophila arenaria), except where breached for home sites and by trails from the residential area to the surf zone. Its present height is approximately 35 feet above mean high tide level, increasing at a rate of about 0.5 feet yearly as sand accumulates in the vegetation. The extreme high tide line has moved as much as 300 feet seaward since 1939 (Figure 5). Part of this general accretion is the building of what appears to be a new foredune as much as 300 feet seaward of the 1939 foredune.... Blowing sand will continue to be a problem where the foredune has been breached and where there are expanses of unvegetated sand.

Sandspits have been described as oscillatory in that they may experience irregular cycles of erosion and deposition. If the spit at Alsea is currently prograding, the situation could reverse at any time.

Note the last two paragraphs – it seems unnecessary to say anything more. The coast is a good teacher, we are just lousy learners.

Tom, Dick, Harry, and George - sand and The Great Escape

 

The plan to dig down to the workshop at the starting point of the tunnel known as Harry, where the wartime fliers began their effort to tunnel beneath the barbed wire, was aborted when engineers failed repeatedly to prevent tons of sand from collapsing their own access tunnel.

“The tunnel known as Harry” was one of the incredible constructions by the prisoners of Stalag Luft III, the escape tunnels, laboriously and ingeniously built, that would be immortalised in the movie, The Great Escape. But this story did not need a movie for immortality – it was extraordinary enough in reality. And now a geoarchaeological project, led by Hugh Hunt, a Cambridge University engineering professor, has shed further light on just how extraordinary it was.

The prisoner of war camp was built, intentionally, on the sandy soils of the forests of today’s western Poland, along the banks of the Bóbr river. Intentionally, because the river valley is filled with sandy sediments deposited from melt waters of the Ice Age glaciers and carried by the ancestral Bóbr. And sand is difficult to tunnel through. Very difficult.

An earlier geoarchaeological expedition to the site of Stalag Luft III was reported in a fascinating article by Peter Doyle and his colleagues that includes a geological assessment of these soils. The following illustration of the sands is taken from their work:

A thin grey organic soil is underlain by glacio-fluvial cross-bedded sands, yellow and reddish-yellow in colour. As the authors point out, this in itself was a problem for the would-be escapers – the excavated sand from the tunnels was immediately visible if deposited against the darker topsoil.

There were numerous tunnelling attempts made at Stalag Luft III, each tunnel given a name, but the events captured in The Great Escape related to Harry. Harry was 330ft long, made from 4,000 bed boards and dug with thousands of pieces of cutlery. The ingenuity and engineering were astonishing – and, as Hunt discovered, impossible to reproduce without unacceptable danger. The movie was based on the book of the same name by Paul Brickhill, whose illustration of the project was reproduced in the article by Peter Doyle and his colleagues:

 
The escape would end in tragedy for all but three of the 76 prisoners who emerged from the tunnel on that March night in 1944. “Following the escape, it is estimated that 5 million Germans were mobilized to recapture them. Of the 76 that escaped, 3 eventually reached Allied territory, but the remainder were recaptured, and 50 of them were executed by the Gestapo.”

One of the remarkable details of Hugh Hunt’s recent project was that one of the team was Frank Stone. Now 89, Frank was waiting his turn to enter the tunnel that night when the escape was discovered. As reported in the Daily Mail, he demonstrated the use of the trolleys made to move men quickly down the tunnels:

Memorials now mark the sites of the entrance and exit to Harry:

 
Hunt’s work was the subject of a recent documentary on British TV, and compellingly described in the following piece from The New York Times:

Latter-Day Dig of ‘Great Escape’ Tunnels Humbles Modern Engineers

By JOHN F. BURNS

CAMBRIDGE, England — For scale, they were no match for the Great Pyramids of Giza or the Panama Canal. The labor took months rather than years and a work force of barely 100 men. As for materials, there were none, beyond what the captured Royal Air Force fliers who built them could scavenge, scrounge or improvise.

But by the measures of ingenuity, courage and persistence, the tunnels built almost 70 years ago in sandy scrubland near the small town of Zagan, 130 miles southeast of Berlin in what was then Hitler’s Germany and is today western Poland, were a legendary feat of engineering, although on a miniature scale.

Chronicled by the 1963 movie “The Great Escape,” the tunnel building is one of World War II’s great stories. In the decades since, the legend of the allied fliers’ mass breakout on the night of March 24, 1944, together with the ingenious planning and the Nazi retribution that followed — 73 of the 76 escapers recaptured, and 50 of them summarily executed on Hitler’s orders — has, in a way, eclipsed reality.

In an effort to establish more clearly how the escape was accomplished — and, in a sense, to reclaim the narrative of the breakout — British-based engineers, battlefield archaeologists and historians traveled into the pine forest outside Zagan last summer to unearth the secrets buried there for a television documentary by Wildfire Television in London that was broadcast in late 2011 in Britain. They were accompanied by modern-day Royal Air Force pilots, as well as veterans of wartime bombing raids, now in their 80s, who helped build the tunnels at the encampment known as Stalag Luft III.

The team’s task was to employ “reverse engineering” by uncovering the tunnels and what remained of the tunnelers’ jury-rigged equipment to replicate the wartime fliers’ ingenuity. Ultimately, the team members were stunned that, even without the menace of the ever-watchful Nazi camp guards, they were unable to match their wartime counterparts fully, particularly in the most crucial skill, digging a tunnel 30 feet below the camp surface without repeated collapses of the sandy soil above.

For years, veterans and others have pored over the camp’s ruins, laying memorial stones amid the outcroppings of broken brick and concrete scattered among the pine trees, all that remains of the 60-acre site built by the Germans to house 10,000 captured fliers. But no group matched the expertise of the 2011 team, which went determined to lay bare what Hugh Hunt, a Cambridge University engineering professor, described as “the final secrets of a remarkable story.”

A maverick Australian affectionately nicknamed Dr. Screwloose by his colleagues, Dr. Hunt went to Poland as a consultant to the current R.A.F. pilots, including some with combat experience over Iraq and Afghanistan. Their task was to use insights gleaned from the digs at the sites of wartime tunnels known as Harry and George to build a new 35-foot tunnel they called Roger, after Squadron Leader Roger Bushell, the principal organizer of the 1944 escape and one of those executed by the Nazis.

“What those men did at Stalag Luft III was an astonishing feat of improvisational engineering,” Dr. Hunt, 50, said in an interview at Cambridge’s Trinity College. “Their resourcefulness was beyond belief. It wasn’t a case of one man’s genius, more the accomplishment of a team, one man’s skills complementing another’s. And they had one precious resource, time. If you have time, somebody will eventually come up with something, and the others will say, ‘Let’s give it a go.’ ”

Like others who joined in the expedition to Zagan, Dr. Hunt has little quarrel with the escape story as told in the film version, which was based on Paul Brickhill’s book of the same name, partly because the tunnelers’ real-life drama required little embellishment. The wartime camp, for one thing, did not have a Virgil Hilts, the irrepressible American flier played by Steve McQueen, and there was no climactic sequence like his flight from German troops on a stolen BMW motorcycle and entanglement in a border fence, one of cinema’s great chase sequences.

The plan to dig down to the workshop at the starting point of the tunnel known as Harry, where the wartime fliers began their effort to tunnel beneath the barbed wire, was aborted when engineers failed repeatedly to prevent tons of sand from collapsing their own access tunnel. But Dr. Hunt and his team struck gold in the excavation of George, a tunnel built under the camp auditorium after the escape and designed to give inmates a place to hide as Nazi control east of Berlin collapsed before advancing Soviet troops.

Their dig yielded a set of rusting trolley wheels, the metal scavenged from remnants of a campsite stove and a coil spring taken from prison gramophones; wood paneling for the tunnel’s roof and sidewalls, fashioned from the prisoners’ bed boards; and a ventilation pump with a bellows and piping made from a prisoner’s kitbag, ice hockey sticks and tins of powdered milk. The pièce de résistance was a rusting radio made from a biscuit box, the wiring stolen from the prisoners’ huts and batteries scrounged from German guards.

The contemporary Royal Air Force fliers built Roger, the replica tunnel, but in a trench just beneath the surface; anything deeper was deemed too dangerous. With Dr. Hunt, they fashioned a trolley system, given its first run in the new tunnel by Frank Stone, 89, a camp veteran involved in preparing the 1944 escape plan. The 2011 team also built a replica of the original tunnelers’ ventilation system, with facsimiles of wartime milk tins and a World War II kitbag.

Mr. Stone, maker of the biscuit-tin radio found in the excavated remains of tunnel George, was one of those still waiting for his turn to escape when a German guard spotted one flier scrambling from the tunnel exit into the pine trees. He remained a prisoner until the camp was liberated in 1945, with a lifetime to grieve for the men who made it, if only briefly, to freedom. “People say to me, ‘How unlucky you were,’ ” he told the documentary makers. “But I say, no, I was lucky to have taken part in it at all.”

 

[Memorials images Lech Muszynski/European Press Photo Agency and http://www.raf.mod.uk/project104/gallery/stalagluftiiigallery.cfm?viewmedia=3]

Sandstorm

It begins with a dance. The wind playing games with the sand and the sand playing along. Ephemeral flurries, a shape-shifting fabric of turbulence, scurrying grains. It’s a compelling and alluring show, but, at the same time, as the wind gathers, the air begins to become oppressive and the brilliant blue sky takes on a threatening dullness as the cargo of dust changes the spectrum. The ephemeral flurries become continuous sheets of sand hurtling across the desert surface, assailing everything in their path. The sun is dimmed.

And then suddenly, seemingly out of nowhere, this streaming chaos turns into the full fury of a sandstorm, a full-blown assault, threatening everything.

Ahmed Hassanein Bey was a highly educated Egyptian, a diplomat and tutor to the king, but a man with deep Bedouin roots. He was the first to cross the Libyan Desert, from the Mediterranean to Sudan in a perilous eight-month journey by camel in 1923; in his extraordinary account of this journey, The Lost Oases, he describes the frequent sandstorms encountered:

It seems as the whole surface of the desert were rising in obedience to some upthrusting force from beneath. Larger pebbles strike against the shins, the knees, the thighs. The spray of dancing sand grains climbs the body till it strikes the face and goes over the head. The sky is shut out, all but the nearest camels fade from view, the universe is filled with hurtling, pelting, stinging, biting legions of torment...It is as though some great monster of fabled size and unearthly power were puffing out these hurtling blasts of sand upon the traveller’s head. The sound is that of a giant hand drawing rough fingers in regular rhythm across tightly stretched silk.

When a sandstorm comes, there is nothing to do but to push doggedly on. Around any stationary object, whether it might be a post, a camel or a man, the eager sands swiftly gather, piling up and up until there remains only a smoothly rounded heap. If it is torture to go on, it is death itself to halt.

During my expedition to the Western - or Libyan – Desert a few years ago, we were assailed by two full-blown sandstorms, the second one far worse than the first. In this age of motor travel, stopping is, unlike in the days of camel transport, the only option, unless frosted windscreens and severe testing of the seals of mechanical components are wished for. The system, well-practised by our drivers and guides, is to circle the wagons – form the vehicles into a square and lash large pieces of heavy fabric between them in an attempt to provide shelter. The attempt can only be partially successful - Hassanein Bey again:

The storm drives the sand into everything one possesses. It fills clothes, food, baggage, instruments, everything. It searches out every weak spot in one’s armour. One feels it, breathes it, eats it, drinks it – and hates it. The finest particles even penetrate the pores of the skin, setting up a distressing irritation.

Our real humdinger of a sandstorm, one that our guides ranked among the worst they had experienced, was in the White Desert, an iconic and spectacular landscape of white limestone sculptures, created by the wind with sand as its tool.

The wind had been gathering all afternoon, the air becoming oppressive, and the sky increasingly dull. As the storm gathered, I had stupidly attempted to put up a tent, but had to give up with the job only half-done. Determined to make the most of the experience, I huddled into the doorway of the semi-erected tent, wrapped a long piece of blue-dyed Moroccan cotton fabric around my head and face in an amateurish imitation of a Tuareg, and took out my notebook. The earth was on the move. As miniature sand dunes migrated past, and the hissing, spattering sound of the grains grew in volume, the burial process began. Piles of sand accumulated rapidly against my legs and began to weigh down the defenceless side of the tent. I tried to scribble down my account, but even a pencil had problems and sand accumulated in the hinge of my notebook (grains still fall out when I open it today). I watched some of my companions trying to put up their tent, and the drivers scrabbling to get some kind of shelter lashed down between the Landcruisers. There were no camels by which to judge visibility, but only during the occasional brief lull in the onslaught could this nearby scene be discerned with any clarity.

It was during one of these brief moments that, perhaps driven to dementia by the granular onslaught, I completely lost control of my senses and took out my camera.

There were two results of doing this – one photograph, and, ever after, a scratching sound when adjusting the telephoto lens.

I gave up, and battled my way to the shelter where my companions huddled, sharing the now very limited supplies of single malt whisky. Somehow, amazingly, in this mayhem, the cooks produced food; sleep that night was intermittent, but I remember being awakened at one point because the noise had stopped. And dawn was miraculous. There was no sign of the storm (other than the piles of sand marking buried tents), but rather a crystalline clarity, a sense that the desert had been cleansed.

 
And, suddenly, there was this colourful and fearless little bird strutting about in the sand – where could it possibly have sheltered overnight during the storm?

 

This was a staggeringly beautiful landscape, but one completely different from the previous day: immeasurable, unimaginable, volumes of the earth’s fabric had been moved, wholesale, from one place to another.

 

[This is my contribution to The Accretionary Wedge, December 2012, hosted by Ron Schott, with the theme “The Most Memorable Geological Event That You’ve Directly Experienced.”]

Playing in the sand box – continuing connections

 
What do all these images have in common? Well, immediately, it’s quite obvious: they are all 3D models of landscapes. But the thinking, the execution, and the technology behind them is fascinatingly different. And yet all are enticing in some way or another – the still images are not sufficient, and the viewer yearns to touch, to interact, to play with them.

I will readily confess to a couple of fascinations: three-dimensional models of how our planet works, and connections, those odd intersections between the seemingly different. I wrote a little about the first fascination in celebrating the early personal influence of the models such as the one in the centre, above, for an Accretionary Wedge event a couple of years ago with the theme Inspiration - the beginnings of a geologist.

...the book which I now appreciate fired my fascination with geology was The Earth’s Crust—A New Approach to Physical Geography and Geology. Published in 1951, it was called “a new approach” because Dudley Stamp commissioned huge, detailed models of different landscapes—and what lies beneath them—to be made in exquisite detail by Tom Bayley, a lecturer in sculpture, and photographed in colour for the book.

Fascination number one in many respects lay behind my previous post on the brilliant linkage between sand box modelling and digital technology, Simtable (bottom left, above). I was delighted that Simtable’s inventor, Stephen Guerin, immediately commented, and included a link to Solid Terrain Modeling, who print high quality graphical data on to 3D landscape models (top left, above). All of this started to stimulate fascination number two, and I found myself visualising some the wonderfully dynamic stream table modelling capabilities that Steve Gough’s Little River Research and Design produces (top right, above). I enjoy following Steve’s activities, developments and applications (entertainingly chronicled on his blog), and I began to wonder if there wasn’t some interesting intersection potential between the Simtable technology and his. I dropped Steve an email and, in spite of being caught up in the challenges of exhibiting – in the end, successfully (see his blog) - at the AGU conference in San Francisco, he replied immediately and commented on the blog post. He provided a link to a description of the SandyStation, an invention by two students at the University of West Bohemia in Pilsen in the Czech Republic, that cleverly combines a physical sand box and the digital technology of the Xbox Kinect (lower right, above).

And then, in browsing around for images, I happened upon this description of what seems like essentially the same conspiracy of sand and the Xbox, but invented by game developers in the Netherlands:

In a refreshingly different take, the world of the game Mimicry is the “ultimate sandbox game” – set in a literal sandbox. Participants manipulate piles of real sand, as Kinect-powered cameras track their work and project imagery onto the sand from a rendered analog version of the same world. The player mimics the virtual, the virtual mimics the player, and the stuff of each fuse in a real/virtual hybrid in sand.

I’m a little confused by this, but that’s not my point. It simply seems to me that here are multiple possibilities for connections, for educational and other applications that might generate examples of the whole being greater than the sum of the parts. And one thing that’s compelling about much of the imagery from all of these activities? They all feature interaction, the satisfaction of being able to touch – and to play.

[Images from Simtable, Solid Terrain Modeling, SandyStation, and Little River Research and Design]