If you pry open one of today’s ubiquitous high-tech devices — whether a cellphone, a laptop, or an
The post Going solid-state could make batteries safer and longer-lasting has been published on Technology Org.
The American Southwest suffered a serious environmental crisis last week, after an Environmental Protection Agency effort to clean up old mining waste went disastrously awry, breaching a containment dam and releasing millions of gallons of contaminated water into the Animas River. The city of Durango and San Juan County in Colorado, as well as the Navajo Nation (the largest Native American reservation in the U.S.), have declared a state of emergency, instructing their citizens to stay out of the water and avoid using it for agriculture or drinking for the time being.
It's a giant screw-up by the EPA, which is scrambling to fix the problem. Yet it's one that could not have happened without a monstrous failure of private industry, which means it bears directly on the 2016 presidential race, in which environmental issues will play an important role. The Animas River debacle shows that Republican dogma — which says that pollution is basically no problem and that the EPA should be sharply restricted, if not abolished altogether — is tantamount to a pro-poisoning position.
Mining has long been a fixture of the Mountain West, but it has slowed considerably from the go-go days of the 19th and early 20th centuries. Much of that was hardrock mining of gold and silver, which require very dangerous chemicals and the processing of thousands of tons of ore. Colorado is thus littered with thousands of abandoned mines, and the Animas watershed was no exception, with 400 old mines.
This is a problem, because the mountain mines inevitably fill with water that has leached through the rock, carrying heavy metals and other toxins with it. Cleaning this up is very expensive, and mine companies would obviously prefer not to do it. Early mine investors were notorious for setting up a shell mining company, extracting the material while paying their executive class a fantastic salary, setting up a token cleanup operation (or forgoing it altogether), then declaring bankruptcy and starting all over again.
That's the profitable, job-creating businessman's solution to mining waste: just poison the neighborhood, then skedaddle. Hey presto, someone else's problem!
However, as regulations became more stringent (especially thanks to the Clean Air and Clean Water Acts), things changed. In general, companies (like Anaconda Copper) now work with the EPA and local communities to clean up old sites, often at great expense.
It was one of those old pools of mining waste — around Silverton, Colorado — that the EPA was testing when it accidentally breached a containment dam and released the water. It's been a big problem for years; the EPA and the mine company have pushed for Superfund designation (which would have made more money available for cleanup), while locals have resisted, fearing for their property values.
Again, clearly the EPA is at fault here. But it's also worth noting that this spill is relatively minor compared to previous similar incidents, and that the dam would have likely burst on its own eventually. The question is what to do about it. Left to its own devices, it's quite obvious what private industry would do: nothing. When it comes to environmental externalities, there is simply no alternative to some kind of government policy. And since the waste is already in place, there is no way to set up a Pigovian tax scheme that would deter such waste in the first place. It's the EPA or bust.
Nevertheless, bust is basically the Republican position. At every turn during the Obama years, they have advocated for fewer environmental controls, greater freedom for corporations to pollute the environment, a cut in EPA funding, and attacks on the science that makes the regulations possible. During the 2012 campaign, the EPA's "job killing regulations" became something of a Republican catechism. These days, Sen. Joni Ernst (R-Iowa) wants to abolish the agency altogether, while Sen. James Inhofe (R-Okla.), the chair of the Senate's environment committee, has merely compared it to the Gestapo.
Ironically, new rules stemming from the Clean Water Act have been the subject of particular conservative ire of late. A minor update in a rule interpreting the Clean Water Act sparked furious Republican outrage, as well as a proposal to abolish the rule that would make it dramatically harder to regulate American rivers and streams.
On pollution, the magic of the free market is supposed to be what takes the place of sclerotic EPA bureaucracy. You only have to look back to the Gilded Age to see what a farcical idea that is. The Republican utopia is one where cities suffocate under a cloud of choking smog; where the hearts of American children pump lead-clouded blood; and where drinking water will be sacrificed to pad corporate profits.
Forests eat a lot of carbon dioxide — roughly a quarter of humanity's total yearly output. So when it comes to the future trajectory of climate change, the behavior of forests is one of the largest potential variables. If forests grow and thrive as the concentration of atmospheric carbon dioxide increases (thus providing them more potential food), then climate change could be strongly mitigated.
On the other hand, if changing weather patterns fueled by global warming kill them off instead, they could release much of the carbon contained in their wood, as they die and rot. The potential range is enormous, says climatologist Dr. William Anderegg, associate professor at the University of Utah and lead author of a new paper in Science on trees and drought. By 2100, world forests could go from a net carbon sink of roughly six billion metric tons per year, to a net source of about the same size.
Anderegg's paper is about hysteresis in forests, a term that might be familiar from economics. Climate change will likely cause increased drought as it gets worse, and just as long spells of unemployment can have lingering effects on those who suffer it, "droughts have lasting effects on ecosystems of forests," says Anderegg. Forests grow slower during droughts, of course, but they also grow slower after the drought is over. In the first year after a drought, Anderegg and his team found trees grew an average of about 9 percent slower; in the second year about 5 percent. They estimate this effect could result in a 3 percent decline in the total carbon stored across their sample size by 2100.
The study also reveals a significant weakness with most major climate models. "Most models don't have mechanisms for drought stress," says Anderegg. Instead, they have a light-switch model, where drought has negative effects while it's happening, but they vanish instantly when the drought is over. He and his colleagues are working to incorporate their drought results into climate models. It's a tricky task, since the models are already very complicated and computationally heavy, but they are close to developing a streamlined technique that can capture most of the measured effects, he says.
This figure shows the overall average effect of drought across the sample size on the right, the difference between wet and arid forests in the middle, and the difference between Pinaceae (the pine tree family) and Fagaceae (that of beech and oaks) on the right:
However, one must be careful not to over-generalize at this point. Anderegg and his team mostly studied semi-arid forests in North America and Europe. Tropical and boreal forests — which make a far greater proportion of forests overall — were largely not studied.
The reason they didn't is simply measurement challenge. Tropical forests, in particular, are dramatically more difficult to study, because most of the trees do not create rings as they grow. (Since the tropics typically don't have regular seasons, growth is basically even and constant.) Without rings, then one is forced to rely on foliage studies from satellites or aerial photography, which are reasonably easy to do but don't contain the whole history of each tree. Or, one can go into the forest and take regular manual measurements of tree size, which is similarly missing the history, and is also enormously labor-intensive. (Not to mention the fact that many tropical regions, like the Democratic Republic of the Congo, are chronically unstable with poor infrastructure.)
However, this study is still suggestive. The 3 percent figure given above is "almost certainly an underestimate," says Anderegg. Drought does not just weaken trees, it also kills them. Studies on recent drought in the Amazon and Borneo found significant mortality, particularly among the largest trees. More recently, scientists have found a slowing rate of carbon uptake in the Amazon.
So in context, Anderegg's paper is a reasonably strong piece of evidence pointing towards the hypothesis that forests will not be a net carbon sink. Best not to pin our hopes for climate change on future mega-forests.
Last Friday, 21 August, ESA’s billion-star surveyor, Gaia, completed its first year of science observations in its main survey mode.
The crime scene investigators on TV’s popular CSI: Crime Scene Investigation series seem able to solve any mystery
The post A new CSI tool could pinpoint when fingerprints were left behind has been published on Technology Org.
Researchers from Lawrence Livermore National Laboratory (LLNL) and a Bay Area company are joining forces to explore how
The post LLNL teams up with Autodesk to investigate design of next-generation materials has been published on Technology Org.
Reducing graphene oxide to graphene via a high-temperature treatment increases thermal conductivity along the film direction, while decreasing it across the film. Scientists from UC Riverside, Moldova State University, and Graphenea see the potential of this new method in thermal management.
Graphene possesses an extremely high thermal conductivity along the sheet plane, making it a candidate for thermal management applications, for example as a filler in thermal interface materials, or as a flexible heat spreader for cooling today's demanding electronics. One of the most researched forms of graphene for industrial applications is graphene oxide (GO), a material produced with scalable and rather inexpensive methods. Having demonstrated excellent mechanical properties, GO has trailed behind other forms of graphene in electrical performance and in thermal conductivity. Current research shows that thermal conductivity of GO can be increased nearly 30 times by bringing GO to a high temperature during a reduction process.
The research team, led by Prof. Alexander Balandin of the Nano-Device Laboratory at University of California Riverside, in their paper entitled “Strongly Anisotropic Thermal Conductivity of Free-Standing Reduced Graphene Oxide Films Annealed at High Temperature” recently published in Wiley's Advanced Functional Materials, present the discovery that GO, when heated to 1000°C, turns to reduced GO (rGO) that has a high thermal conductivity along the sheet plane. In contrast, thermal conductivity perpendicular to the sheet shows an opposite trend, decreasing with thermal treatment. This seemingly confusing conclusion is elegantly explained with detailed characterization and theoretical support.
Image: Sketch of air pockets impeding heat transport perpendicular to the graphene sheets, and a SEM image of the same.
The first observation that the scientists made was that the film swelled when heated, its thickness increasing more than four times. Dissecting the film and looking from the side, the researchers discovered that the rGO is infiltrated by air pockets longitudinal to the film. Hypothesizing that the air pockets provide thermal insulation across the film, the scientists developed a theoretical framework which supports this finding at several different annealing temperatures. Heat flows uninhibited in the film plane, however, and heat transfer is further enhanced by the strengthening of carbon bonds and the chemical purification induced by the annealing.
The anisotropy of heat conductivity in such obtained rGO is exceptionally high even when compared to high-quality graphite. As such, this new material holds much promise for thermal management applications where one would want to remove excess heat along one direction while shielding from heat along the perpendicular direction.
