from the world's big
Scientists invent method to extract gold from liquid waste
The next gold rush might take place in our sewers.
- Even though we think of it as exceedingly rare, gold can be found all around us.
- The trouble is, most of the gold is hard to get at; its too diluted in our waste or ocean waters to effectively extract.
- This new technique quickly, easily, and reliably extracts gold from most liquids.
Even though the thought of gold calls to mind incredible wealth hidden underground or horded away in Fort Knox, you can actually find the stuff all over the place. there's gold in nearly every kind of consumer electronic, gold in our sewage, gold in the cracks of New York City sidewalks, and even trace amounts in our brains. The trouble isn't that gold is rare, per se, it's just hard to get to.
In human history, we've mined about 190,000 tons of gold out of the ground. If you want to visualize that amount, it would fit in a box about 20 m on each side; not all that much in the grand scheme of things. We've been able to get at this because it was stored in a way that's relatively easy for us to access. It was buried in the Earth, so we just had to dig it up. In contrast, we've estimated that there's about 20 million tons of gold in the ocean—it's just distributed throughout the seas, making it difficult to refine and extract.
In the past, we didn't use gold for much of anything besides as a method to store value, so the fact that most gold on Earth was inaccessible was more of a feature than a bug. But now, we're increasingly finding practical applications for the precious metal. It can be used in medicine to treat arthritis or for dentistry; it's an excellent conductor, so it can be used in electronics and communication technology; and it reflects infrared radiation, so we use it on our spacecraft and spacesuits. Suddenly, getting at those 20 million tons of gold in the ocean and elsewhere on Earth has become more about technological and societal progress than about accumulating wealth.
New research from the Journal of the American Chemical Society has uncovered one of the most effective methods to date to extract gold from liquids. That includes electronic waste, sewage, ocean water, waste water—almost any liquid where we might find gold. Just to highlight how potentially useful this is, sewage from Switzerland alone is estimated to carry away 1.8 million dollars' worth of gold every year.
Making a sponge for gold
The object to the left shows the basic framework, a lattice of iron ion clusters connected by organic molecules. On this structure, a polymer that helps catch gold is coated, represented by the purple dots.
Sun et al. 2018
The method consists of a metal-organic framework—essentially, clusters metal ions connected by an organic "skeleton." In this case, the framework consists of iron ions connected by an organic compound called 1,3,5-benzenetricarboxylate. The researchers then coated this structure in a polymer with an even more difficult-to-pronounce name (for the curious, it's poly-para-phenylenediamine, or PpDA), which helps the framework catch stray molecules of gold.
Essentially, the framework and polymer work as a very granular sponge, only this sponge doesn't hold soap or water; instead, it holds gold.
Other researchers have built structures like this one before, but the new framework works exceptionally well. For every gram of this gold-seeking sponge submerged in a liquid, it can hold up to a gram of gold. What's more, it can catch 99% of the gold in a given solution in as little as two minutes.
Once the framework's sucked up the gold, it can easily be destroyed to retrieve the gold captured inside. The figure below shows how this works. After it's been suspended in a gold-containing solution, the framework is dissolved in hydrochloric acid. After some time, all that's left is 23.9 K gold, which is the highest purity of gold reclaimed from similar projects.
On the left, a sample of liquid is shown with the new material suspended inside. After the material is dissolved in acid, 23.9 K gold particles are leftover. On the right side, the gold particles are shown under a microscope.
Sun et al. 2018
The researchers tested the method out in a few different real-world cases. One of the most useful applications for a method like this is in reclaiming gold from electronic waste. It can take as much as a ton of gold ore to build just 40 smartphones, so getting the gold out of electronic waste would be extremely practical.
The researchers physically removed the metal from a CPU and treated it with some chemicals to form a solution. In the figure below, you can see that this produced a blue solution. So far, this technique is nothing new. The trouble is that a CPU also contains copper and nickel as well as gold, all of which is mixed up in this solution. So, the trick is how to get the really valuable metal out of the mixture. Using the new method, the researchers managed to get 95% of the gold out of the solution.
The top-left image shows a regular CPU. To its right, we can see the various elements that comprise the CPU (copper, nickel, and gold). In the bottom-left corner, we can see the CPU after its material has been physically removed. The image to its right shows the material dissolved into a blue solution and a graph showing how much of each material the new method recovered from the solution.
Sun et al. 2018
They found similar results with different liquids, too. The new framework captured 99% of gold from Swiss sewage (which, if you'll recall, allegedly washes away $1.8 million worth of gold every year). The researchers also tried extracting gold from seawater, and, once again, they were able to extract 99% of gold from their sample. These last two examples are especially promising; sewage and seawater contain a huge variety of different compounds that could interfere with any kind of filtering system.
We're still a long way off from, say, filtering the oceans for the precious metals they contain. But as we continue to use up the easily accessible resources buried in the Earth, exploring new techniques like this will be important if we want to continue to use smartphones, explore space, and collectively advance as a society.
Andy Samberg and Cristin Milioti get stuck in an infinite wedding time loop.
- Two wedding guests discover they're trapped in an infinite time loop, waking up in Palm Springs over and over and over.
- As the reality of their situation sets in, Nyles and Sarah decide to enjoy the repetitive awakenings.
- The film is perfectly timed for a world sheltering at home during a pandemic.
Richard Feynman once asked a silly question. Two MIT students just answered it.
Here's a fun experiment to try. Go to your pantry and see if you have a box of spaghetti. If you do, take out a noodle. Grab both ends of it and bend it until it breaks in half. How many pieces did it break into? If you got two large pieces and at least one small piece you're not alone.
But science loves a good challenge<p>The mystery remained unsolved until 2005, when French scientists <a href="http://www.lmm.jussieu.fr/~audoly/" target="_blank">Basile Audoly</a> and <a href="http://www.lmm.jussieu.fr/~neukirch/" target="_blank">Sebastien Neukirch </a>won an <a href="https://www.improbable.com/ig/" target="_blank">Ig Nobel Prize</a>, an award given to scientists for real work which is of a less serious nature than the discoveries that win Nobel prizes, for finally determining why this happens. <a href="http://www.lmm.jussieu.fr/spaghetti/audoly_neukirch_fragmentation.pdf" target="_blank">Their paper describing the effect is wonderfully funny to read</a>, as it takes such a banal issue so seriously. </p><p>They demonstrated that when a rod is bent past a certain point, such as when spaghetti is snapped in half by bending it at the ends, a "snapback effect" is created. This causes energy to reverberate from the initial break to other parts of the rod, often leading to a second break elsewhere.</p><p>While this settled the issue of <em>why </em>spaghetti noodles break into three or more pieces, it didn't establish if they always had to break this way. The question of if the snapback could be regulated remained unsettled.</p>
Physicists, being themselves, immediately wanted to try and break pasta into two pieces using this info<p><a href="https://roheiss.wordpress.com/fun/" target="_blank">Ronald Heisser</a> and <a href="https://math.mit.edu/directory/profile.php?pid=1787" target="_blank">Vishal Patil</a>, two graduate students currently at Cornell and MIT respectively, read about Feynman's night of noodle snapping in class and were inspired to try and find what could be done to make sure the pasta always broke in two.</p><p><a href="http://news.mit.edu/2018/mit-mathematicians-solve-age-old-spaghetti-mystery-0813" target="_blank">By placing the noodles in a special machine</a> built for the task and recording the bending with a high-powered camera, the young scientists were able to observe in extreme detail exactly what each change in their snapping method did to the pasta. After breaking more than 500 noodles, they found the solution.</p>
The apparatus the MIT researchers built specifically for the task of snapping hundreds of spaghetti sticks.
(Courtesy of the researchers)
What possible application could this have?<p>The snapback effect is not limited to uncooked pasta noodles and can be applied to rods of all sorts. The discovery of how to cleanly break them in two could be applied to future engineering projects.</p><p>Likewise, knowing how things fragment and fail is always handy to know when you're trying to build things. Carbon Nanotubes, <a href="https://bigthink.com/ideafeed/carbon-nanotube-space-elevator" target="_self">super strong cylinders often hailed as the building material of the future</a>, are also rods which can be better understood thanks to this odd experiment.</p><p>Sometimes big discoveries can be inspired by silly questions. If it hadn't been for Richard Feynman bending noodles seventy years ago, we wouldn't know what we know now about how energy is dispersed through rods and how to control their fracturing. While not all silly questions will lead to such a significant discovery, they can all help us learn.</p>
The multifaceted cerebellum is large — it's just tightly folded.
- A powerful MRI combined with modeling software results in a totally new view of the human cerebellum.
- The so-called 'little brain' is nearly 80% the size of the cerebral cortex when it's unfolded.
- This part of the brain is associated with a lot of things, and a new virtual map is suitably chaotic and complex.
Just under our brain's cortex and close to our brain stem sits the cerebellum, also known as the "little brain." It's an organ many animals have, and we're still learning what it does in humans. It's long been thought to be involved in sensory input and motor control, but recent studies suggests it also plays a role in a lot of other things, including emotion, thought, and pain. After all, about half of the brain's neurons reside there. But it's so small. Except it's not, according to a new study from San Diego State University (SDSU) published in PNAS (Proceedings of the National Academy of Sciences).
A neural crêpe
A new imaging study led by psychology professor and cognitive neuroscientist Martin Sereno of the SDSU MRI Imaging Center reveals that the cerebellum is actually an intricately folded organ that has a surface area equal in size to 78 percent of the cerebral cortex. Sereno, a pioneer in MRI brain imaging, collaborated with other experts from the U.K., Canada, and the Netherlands.
So what does it look like? Unfolded, the cerebellum is reminiscent of a crêpe, according to Sereno, about four inches wide and three feet long.
The team didn't physically unfold a cerebellum in their research. Instead, they worked with brain scans from a 9.4 Tesla MRI machine, and virtually unfolded and mapped the organ. Custom software was developed for the project, based on the open-source FreeSurfer app developed by Sereno and others. Their model allowed the scientists to unpack the virtual cerebellum down to each individual fold, or "folia."
Study's cross-sections of a folded cerebellum
Image source: Sereno, et al.
A complicated map
Sereno tells SDSU NewsCenter that "Until now we only had crude models of what it looked like. We now have a complete map or surface representation of the cerebellum, much like cities, counties, and states."
That map is a bit surprising, too, in that regions associated with different functions are scattered across the organ in peculiar ways, unlike the cortex where it's all pretty orderly. "You get a little chunk of the lip, next to a chunk of the shoulder or face, like jumbled puzzle pieces," says Sereno. This may have to do with the fact that when the cerebellum is folded, its elements line up differently than they do when the organ is unfolded.
It seems the folded structure of the cerebellum is a configuration that facilitates access to information coming from places all over the body. Sereno says, "Now that we have the first high resolution base map of the human cerebellum, there are many possibilities for researchers to start filling in what is certain to be a complex quilt of inputs, from many different parts of the cerebral cortex in more detail than ever before."
This makes sense if the cerebellum is involved in highly complex, advanced cognitive functions, such as handling language or performing abstract reasoning as scientists suspect. "When you think of the cognition required to write a scientific paper or explain a concept," says Sereno, "you have to pull in information from many different sources. And that's just how the cerebellum is set up."
Bigger and bigger
The study also suggests that the large size of their virtual human cerebellum is likely to be related to the sheer number of tasks with which the organ is involved in the complex human brain. The macaque cerebellum that the team analyzed, for example, amounts to just 30 percent the size of the animal's cortex.
"The fact that [the cerebellum] has such a large surface area speaks to the evolution of distinctively human behaviors and cognition," says Sereno. "It has expanded so much that the folding patterns are very complex."
As the study says, "Rather than coordinating sensory signals to execute expert physical movements, parts of the cerebellum may have been extended in humans to help coordinate fictive 'conceptual movements,' such as rapidly mentally rearranging a movement plan — or, in the fullness of time, perhaps even a mathematical equation."
Sereno concludes, "The 'little brain' is quite the jack of all trades. Mapping the cerebellum will be an interesting new frontier for the next decade."
What happens if we consider welfare programs as investments?
- A recently published study suggests that some welfare programs more than pay for themselves.
- It is one of the first major reviews of welfare programs to measure so many by a single metric.
- The findings will likely inform future welfare reform and encourage debate on how to grade success.
Welfare as an investment<p>The <a href="https://scholar.harvard.edu/files/hendren/files/welfare_vnber.pdf" target="_blank">study</a>, carried out by Nathaniel Hendren and Ben Sprung-Keyser of Harvard University, reviews 133 welfare programs through a single lens. The authors measured these programs' "Marginal Value of Public Funds" (MVPF), which is defined as the ratio of the recipients' willingness to pay for a program over its cost.</p><p>A program with an MVPF of one provides precisely as much in net benefits as it costs to deliver those benefits. For an illustration, imagine a program that hands someone a dollar. If getting that dollar doesn't alter their behavior, then the MVPF of that program is one. If it discourages them from working, then the program's cost goes up, as the program causes government tax revenues to fall in addition to costing money upfront. The MVPF goes below one in this case. <br> <br> Lastly, it is possible that getting the dollar causes the recipient to further their education and get a job that pays more taxes in the future, lowering the cost of the program in the long run and raising the MVPF. The value ratio can even hit infinity when a program fully "pays for itself."</p><p> While these are only a few examples, many others exist, and they do work to show you that a high MVPF means that a program "pays for itself," a value of one indicates a program "breaks even," and a value below one shows a program costs more money than the direct cost of the benefits would suggest.</p> After determining the programs' costs using existing literature and the willingness to pay through statistical analysis, 133 programs focusing on social insurance, education and job training, tax and cash transfers, and in-kind transfers were analyzed. The results show that some programs turn a "profit" for the government, mainly when they are focused on children:
This figure shows the MVPF for a variety of polices alongside the typical age of the beneficiaries. Clearly, programs targeted at children have a higher payoff.
Nathaniel Hendren and Ben Sprung-Keyser<p>Programs like child health services and K-12 education spending have infinite MVPF values. The authors argue this is because the programs allow children to live healthier, more productive lives and earn more money, which enables them to pay more taxes later. Programs like the preschool initiatives examined don't manage to do this as well and have a lower "profit" rate despite having decent MVPF ratios.</p><p>On the other hand, things like tuition deductions for older adults don't make back the money they cost. This is likely for several reasons, not the least of which is that there is less time for the benefactor to pay the government back in taxes. Disability insurance was likewise "unprofitable," as those collecting it have a reduced need to work and pay less back in taxes. </p>