Going clean

Crack a simple chemical reaction and we don’t have to kick our addition to fossil fuels

SCARRED landscapes, billowing smoke, seabirds wrinsc_20161008-800x1052thing in liquorice gloop: there’s no denying fossil fuels have an image problem. That’s before we even start to factor in the grave risk continuing to burn them poses to Earth’s climate. But what’s the alternative? Nuclear is expensive, renewables are unreliable, and we are a long way from making batteries that could power our fuel-hungry lifestyles. Realistically, we are going to be reliant on fossil fuels for a while yet.

What we need is a way to exploit them without emitting any planet-warming carbon dioxide. Alberto Abánades thinks he has the answer. He isn’t a PR man for the fossil fuel industry, and nor does he have anything to do with various schemes to capture and bury carbon emissions after the event. He and his research team think they have cracked the problem using chemistry alone. By simply changing the way we liberate the energy trapped inside natural gas molecules, we can have all the benefits of fossil fuels – and none of the guilt. Too good to be true? […]

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The descent of mass

The simultaneous drop of two dissimilar masses is one of the oldest experimental results. But new techniques may show that not everything falls the same way

pwoct16cover-200What goes up must come down. But does everything come back down at the same time? Galileo said yes. Newton said yes. Einstein said yes. Still, many physicists today secretly believe the answer might be no.

That belief might seem strange. Countless experiments over the years have concluded that two objects dropped from a height will – regardless of their composition – fall to the ground at precisely the same moment, provided they do not suffer disparities in air resistance. Schoolchildren are routinely taught about this “universality of free fall”, often with reference to the famous 1971 video of the US astronaut David Scott standing on the Moon and demonstrating that, in the absence of any air, even a feather and a hammer fall in unison. If the universality is not clear from everyday experience, it is at least implied by Newton’s laws of motion and gravitation, which combine to suggest that the acceleration of a body due to gravity is proportional only to the mass of the planetary object it is being attracted to, not to its own mass. The conclusion would appear irrefutable.

Yet, some violation of the universality of free fall could come in very useful. One of the greatest obstacles to progress in physics is the gaping chasm between the classical world of Einstein’s gen- eral theory of relativity, our current best theory of gravity, and the fuzzy, largely microscopic world of quantum mechanics, which accurately describes the other three known forces of nature: electromag- netism; and the strong and weak nuclear forces. A bridge between the two worlds – a quantum theory of gravity – is the neatest theoretical solution, but it has been elusive. Some candidate theories would seem to entail additional forces that, at very fine timescales, create an imbalance in the pull of gravity for different objects. Indeed, the observation of a tiny and hitherto imperceptible difference in acceleration for two falling objects could be the first evidence that general relativity is flawed, ushering in a new paradigm in modern physics.

Before the turn of this century, the best tests of gravitational free fall could find no deviation in the acceleration of two masses to within one part in 10 trillion. But a new host of lab- and space-based experiments promises up to a 10 000-fold increase in this precision, potentially offering the first chance of testing quantum gravity theories. What is more, some experimentalists are presenting new ways to approach tests of free fall – for example, by employing purely quantum systems, or antimatter. The question “Does everything fall back to Earth at the same speed?” may soon have an answer far more accurate than ever before. […]

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Plugging the neutron deficit

As Europe’s neutron supply could fall by as much as half within the next couple of decades, newly developed sources could stave off the decline

There are good reasons to get excited by the European Spallation Source (ESS), which is currently under construction in Lund, Sweden. When the machine finally goes online – and 2028 is the current completion date – it will be the world’s most intense particle accelerator, generating up to 100 times more neutrons than any of today’s sources. Like a giant microscope, it will allow unprecedented studies into various fields – particularly the science of the everyday, such as plastics, pharmaceuticals, biological matter and nanotechnology. The ESS is a fitting tribute to Europe’s neutron research community, which is estimated to be by far the world’s largest, comprising some 6,000 scientists and engineers.

Against this starry-eyed picture, a report published in March by the European Strategy Forum on Research Infrastructures (ESFRI), an EU body, makes for sobering reading. Europe’s neutron community has been fostered over time by a great network of small to large flux neutron sources, two thirds of which were built in the 1960s and 1970s. The majority of these sources are set to close within a decade, and several smaller research reactors have been decommissioned already – those at the Risø National Laboratory in Denmark (in 2000), at Forschungzentrum Jülich (in 2006) and at Gessthacht in Germany (in 2010). Two of the biggest sources – the Orphèe reactor at the Laboratoire Léon Brillouin (LLB) in Saclay, France, and the BER-II reactor at the Helmholtz-Zentrum Berlin in Germany – are expected to close down within four years. By the mid 2030s, according to the ESFRI’s Roadmap, the best-case scenario is a 30% drop in neutron instrument time. The worst-case scenario: a 50% drop.

Simply put, in decades to come the ESS may be a transformative neutron source, but there may not be much of a neutron community left to use it. “The renewal of intermediate neutron sources becomes necessary to maintain a ‘critical mass’ for the neutron user community, otherwise new powerful sources such as the ESS become almost useless,” says Jacques Ollivier, a physicist at the world’s current leading neutron facility, the Institut Laue-Langevin (ILL) in Grenoble, France. The ILL itself is set to close in 2023 unless its partners agree otherwise. […]

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Sharpening up emissions from Asian land-use change

Carbon emissions due to changing land use and land-cover in Asia are becoming increasingly important worldwide, according to an international group of researchers.

Despite a steady decline in carbon emissions since the 1990s in the continent as a whole, South East Asia continues to see high emissions due to deforestation. But emissions due to land-use change are still hard to estimate accurately because of poor land-use definitions in the scientific literature, the team believes.

“A lot of the disagreement in our estimates simply comes from definitions,” said Benjamin Poulter of Montana State University, US. […]

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Bark beetle has ‘little impact’ on US water supply

A study of more than 30 watersheds across the western US has cast doubt on the idea that an epidemic of bark beetles has been affecting water supplies.

Researchers at the Colorado School of Mines, US, found no evidence that outbreaks of the mountain pine beetle have affected peak or average daily streamflows in seven western US states. Instead, the authors believe that changes in streamflow patterns are caused by climatic variability.

“When we did not find a consistent pattern of change in the watersheds impacted [by the mountain pine beetle], we decided to dig a little deeper to see if we could explain why some watersheds were significantly impacted while others weren’t,” said Kimberly Slinski. “This study doesn’t provide conclusive proof that rainfall and temperature patterns are driving the streamflow patterns, but the data clearly show that [they] are related.” […]

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Targeted alkalinization could protect coral reefs

The artificial alkalinization of seawater could protect coral reefs from some of the harm from ocean acidification due to rising carbon dioxide emissions, a study by researchers in Germany has concluded.

The study shows that alkalinization – which could be achieved by distributing lime or other alkaline substances in the ocean – could prevent coral dissolving, although it may have harmful side effects.

“We show that the artificial alkalinization of seawater could be one of several strategies that may be needed in conjunction to protect coral reefs from climate change,” said Andreas Oschlies of the GEOMAR Helmholtz Centre for Ocean Research, Germany. […]

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Ozone concentrations will depend on climate change policies

Rising greenhouse-gas emissions could not only lead to climate change, but also boost stratospheric ozone outside the tropics beyond historic levels, according to scientists in the US and the UK.

A study that explored the prospects for stratospheric ozone under different greenhouse-gas emissions scenarios found that the continued emission of carbon dioxide could over-compensate for lost stratospheric ozone towards the end of this century, leading to less transmission of ultraviolet (UV) radiation.

The consequences are unknown, but could affect ecosystems and levels of vitamin D uptake in humans, the scientists say.

“Stratospheric ozone depletion is generally considered to pose more problems than benefits for human health,” said Amy Butler of the US National Oceanic and Atmospheric Administration. “But having higher stratospheric ozone levels than historically experienced also has implications for surface UV.” […]

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Molecules rev up for world’s tiniest race

Come October, six of the world’s most advanced vehicles will race for glory over a track made of gold. Only you won’t be able to see the groundbreaking event, because each competitor will be just nanometres in size.

This is the NanoCar Race, and it is being held at the materials lab CEMES at the National Center for Scientific Research (CNRS) in Toulouse, France. The idea is to encourage the development of technology made of single atoms and molecules that could one day revolutionise areas such as electronics.

‘It’s not about molecular vehicles per se, it’s about single-molecule mechanics and the way you can miniaturise gears, motors and so on to the atomic scale,’ said molecular scientist Dr Christian Joachim of CEMES.

The nano cars consist of complex single molecules designed by teams of chemists from all over the world. Though invisible to the naked eye, these molecules appear on the atomic scale like a ragbag line-up from Wacky Races – some with wheels, some with wings and some with paddles for propulsion. […]

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Deforestation boosts tropical floods

Deforestation has increased the occurrence of flooding in Indonesian Borneo over the past 30 years, according to researchers in Australia and Indonesia.

Based on interviews with local villagers and articles from local media sources, the study shows that, in just three years, upwards of 750,000 people from hundreds of settlements were displaced by flooding. Those affected are more likely to have come from regions deforested for mining and oil-palm plantations, the researchers say.

“The relationship between land cover and flooding occurrence in the tropics remains unclear, primarily because the data to study these relationships are difficult to obtain for large geographic scales,” said Erik Meijaard of the University of Queensland. “Our study shows that deforestation does increase the frequency of flood events – and this is important in broader sustainable development planning, where often the benefits of deforestation are quite well known but not the costs.” […]

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Assessing uncertainties in image registration

Researchers in the US and Denmark have demonstrated a new way to evaluate the uncertainty of deformable image registration (DIR), which tracks the changes of tumours in medical images. According to the study, which was based on real images of patients with prostate cancer, a “distance discordance metric” (DDM) is better able to evaluate uncertainties in DIR than existing methods. The new method should allow radiotherapists to provide cancer patients with more accurate treatment plans (Phys. Med. Biol. 61 6172).

The aim of radiotherapy is to localize radiation to a tumour while sparing healthy tissue, so that a patient does not have to suffer more radiation than necessary. To do this, radiotherapists make use of medical imaging, such as CT and MRI, to identify a tumour’s boundaries. But this is difficult if the relevant part of the body undergoes motion, or if the patient loses weight or the tumour itself begins to change in size. […]

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