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Updated: 1 hour 19 min ago

NRC debates extending life of aging US nuclear plants

31 August 2016
Nature: Although 20% of US electricity is generated by nuclear power plants, most of the reactors producing that energy are getting old. Many were built in the 1970s and 1980s with a life expectancy of 40 years. The US Nuclear Regulatory Commission has already renewed the licenses of 81 reactors so they can continue running for another 20 years, and now the NRC is considering extending some licenses yet another 20 years. Despite a slew of increasingly sophisticated maintenance inspections to look for defects and signs of wear and tear, questions have been raised over how materials age and the durability of parts that may be hidden from view. Moreover, because of economic constraints, many power companies have been investing only the bare minimum to maintain and upgrade their nuclear plants. It would be better to build new plants with safer and more modern designs than to push old ones past their limits, according to former NRC chair Allison Macfarlane.

Preschoolers should learn particle physics

31 August 2016
If pre-K children can learn numbers and words, why not teach them about quarks and electrons?

Inhabitants of Hawaiian dome complete year-long simulation of life on Mars

30 August 2016
National Geographic: For the past year, six people have been living in a two-story dome, about 2500 meters up the slopes of Mauna Loa in Hawaii. The Hawaii Space Exploration Analog and Simulation (HI-SEAS) project has been designed to simulate what life would be like on Mars, where the inhabitants would live for extended periods of time in close quarters with each other but isolated from the rest of humanity. The remote, rocky slope of Mauna Loa was chosen for its Mars-like features, and the dome’s inhabitants were required to wear a spacesuit when going outside. The most recent experiment was of the longest duration yet and featured a virtual-reality (VR) component that allowed participants to experience different environments and construct their own. From the data collected, scientists hope to determine the extent to which such VR capability could help alleviate the stress of deep-space missions.

Science Committee chairman Lamar Smith delves into fray over Clinton email server

30 August 2016
The Texas Republican says cybersecurity standards issued by NIST provide rationale for an investigation.

SETI radio signal almost certainly didn't come from aliens

30 August 2016

Verge: Last year, a team of Russian astronomers, using the RATAN-600 radio telescope, detected a mysterious signal that came from the general direction of HD 164595, a Sun-like star located 95 light-years away. Because the star has at least one planet, the astronomers say it's possible the signal indicates the presence of an alien civilization. The team only recently shared the discovery with the rest of the SETI (search for extraterrestrial intelligence) community, and no other researchers have yet confirmed the signal. Verifying the discovery will be difficult for several reasons. RATAN-600 was using a wide-bandwidth receiver, so it will be hard to determine the precise source of the signal. Moreover, the signal hasn't repeated, and even if it did, it would be difficult to know where to point other radio telescopes to try to detect it. Since the telescope data suggest that the signal would have required more power than has been consumed by all of humanity, a more likely explanation is that it was caused by a natural phenomenon such as a quasar.

NASA's <em>Juno</em> completes first flyby of Jupiter

30 August 2016

Business Insider: On 27 August NASA's Juno spacecraft performed its first flyby of Jupiter. In doing so, the probe reached 130 000 mph (209 214 km/h), the top speed ever attained by a human-made object. Juno began collecting a range of measurements and also took pictures—the first close-ups of the giant planet since 2007, when New Horizons passed by on its way to Pluto. by the end of 2016, Juno's highly elliptical orbit around Jupiter will bring the probe close to the planet every 14 days for the next 16 months.

Iran releases physicist after five-year imprisonment

30 August 2016
Omid Kokabee has been recovering from surgery for kidney cancer.

Underground ice wall at Fukushima nears completion

30 August 2016
New York Times: Since being damaged during a 2011 earthquake and tsunami, Japan’s Fukushima Daiichi nuclear plant has experienced a number of problems, including the flow of contaminated groundwater into and out of the facility. To try to stem that flow, the Tokyo Electric Power Co (TEPCO) has spent the past two years building an underground ice wall. The Landside Impermeable Wall consists of more than 1500 pipes about 30 meters in length and sunk into the ground at 1-meter intervals. Filled with a brine solution and supercooled to -30 °C, the pipes are expected to freeze the soil around them and create an icy barrier. Following installation earlier this year, the wall was activated in two stages, part in March and the rest in June. Because it can take several months for the soil to completely freeze, TEPCO is still awaiting the results. The plan has been criticized for its high cost and technical complexity.

X-ray ghost imaging

29 August 2016
Creating an image of a fragile object using x rays that never touch it may be an ideal way to circumvent radiation damage.

Majority of mathematicians hail from 24 "families" of academic advisers

29 August 2016

Nature: Since the 1990s the Mathematics Genealogy Project (MGP) has been building family trees for professional mathematicians based on their doctoral advisers. An analysis performed by Floriana Gargiula of the University of Namur in Belgium and her colleagues has found that of the more than 200 000 mathematicians in the MGP database, 65% can be traced back to just 24 families. The analysis was done by combining the MGP data with information from Wikipedia and the Scopus bibliographic database. Overall, the analysis found 84 distinct families. The largest family, with 56 387 descendants, is headed by 15th-century physician Sigismondo Polcastro.

Italy is installing a national earthquake warning system

29 August 2016

New Scientist: In the wake of last week's deadly magnitude 6.2 earthquake in central Italy, the country is preparing for final tests of a national earthquake forecasting and warning system. Italy's Civil Protection Department is developing a system that will collect seismic measurements from around the country and combine that data with mathematical models and historical records. Every three hours the system will spit out a report that predicts the number of earthquakes the country will experience in the next seven days. Warner Marzocchi of the Italian National Institute of Geophysics and Volcanology in Rome says that the system will likely be very good at predicting aftershocks, though it will not be able to predict magnitude. Predicting quakes like last week's will be difficult because of the absence of warning tremors.

Fire whirls could be useful for cleaning up oil spills

29 August 2016

New York Times: Fire whirls are tornado-like phenomena that often occur during large fires. They can be extremely damaging because the vortex causes the fire to burn much hotter. Inspired by a video of a fire whirl that ignited on a spill of bourbon in a pond at the Jim Beam distillery in Kentucky, Huahua Xiao, Michael Gollner, and Elaine Oran of the University of Maryland, College Park, have found that the whirls could possibly help in cleaning up oil spills. They poured n-heptane, an ingredient in some fuels, into a pan of water, ignited it, and then channeled air toward the fire to create a vortex. The resulting fire whirl soon changed from a yellow flame to a blue flame, indicating that burning was occurring at a significantly higher temperature and more efficiently, thereby producing less soot. A subsequent test using crude oil had similar results. The blue fire whirl is, as far as the researchers have found, a previously undocumented phenomenon. The Maryland team hopes to test the phenomenon at a larger scale to determine whether it could be useful for oil-spill cleanup.

Offshore tidal generators connected to electrical grid for the first time

29 August 2016

BBC: When two turbines off the coast of Shetland, an archipelago off northern Scotland, were recently connected to the country's electrical grid, they became the first offshore tidal generators to provide commercial electricity. The two 100 kW generators were installed by Nova Innovation, an Edinburgh-based tidal energy company. Scotland has invested significantly in tidal energy generation because the country has some of the most powerful tides in Europe.

High-resolution mapping confirms rate of Greenland ice sheet melting

26 August 2016

The Guardian: Greenland's ice sheet is one of the largest on Earth. Malcolm McMillan of the Center for Polar Ice Observing and Modeling in the UK and his colleagues recently used the satellite Cryosat-2 to map Greenland with a resolution of 5 km. The satellite uses radar altimetry to measure the height of the surface. By taking images over time, the researchers were able to measure changes in height; an increase in height corresponds to an increase in ice thickness. However, those measurements don't account for changes in density (the top layer could be ice or snow), surface roughness, water content, and other factors. McMillan's team examined the satellite imagery collected between 2011 and 2014 and accounted for all the variations. The scientists calculated that 270 billion tons of ice was lost per year, closely matching previous measurements from other groups using different measurement techniques. They also found that the western part of the sheet experienced more ice loss than the eastern side, and that a region less than 1% of the area of the sheet was responsible for 10% of the ice loss.

South Korea says it can mass produce tritium for fusion reactors

26 August 2016

Korea Times: South Korea's National Fusion Research Institute announced on 24 August that it has developed a process capable of producing 50 kg of tritium breeder pebbles per year. Tritium, a radioactive isotope of hydrogen with one proton and two neutrons, is a common fuel for nuclear fusion reactors. Unlike hydrogen's other isotope, deuterium, tritium does not occur naturally in large quantities and so has to be artificially produced. Previous processes have not produced significant quantities of the isotope. According to the Institute for Energy and Environmental Research, between 1955 and 1996 the US produced an estimated 225 kg of tritium.

Newly found galaxy is 99.99% dark matter

26 August 2016

Washington Post: Dark matter accounts for much of the mass in the universe, but it is not evenly distributed. About 83% of the Milky Way's mass is due to dark matter; the percentage is considerably higher for some dwarf galaxies. Now Pieter van Dokkum of Yale University and his colleagues have found a galaxy, called Dragonfly 44, that has roughly the same mass as the Milky Way yet has only 1% as many stars. The researchers estimate that 99.99% of the galaxy's mass is from dark matter. Because Dragonfly 44 is about average when it comes to galactic size, scientists suspect that similarly dark matter–dominated galaxies are relatively common.

Storm-triggered <em>S</em> waves tracked for first time

26 August 2016

BBC: Earthquakes aren't the only phenomena to send seismic waves through Earth's interior. When a large storm forms water, the energy from colliding ocean waves can create weak seismic activity—dubbed a microseism—that travels through the crust. The pressure-wave microseisms from storms have been tracked regularly, but the transverse S waves, which move much more slowly, have never been tied directly to a storm until now. Kiwamu Nishida from the University of Tokyo and Ryota Takagi of Tohoku University used a dense network of seismic detectors off the Japanese coast to measure S waves and pin their source to a storm off the coast of Greenland. Researchers should be able to learn about Earth's interior structure by comparing the propagation of S and P waves from the same storm.

Journalists scant scientists’ ethnic-profiling accusation against the federal government

26 August 2016
Reporters and editors are mostly overlooking the implications of cases like those of physicist Xiaoxing Xi and hydrologist Sherry Chen.

Octopus-inspired robot flexes its muscles

25 August 2016
NPR: A newly built soft-bodied robot looks like a baby octopus and can wiggle its legs when fed a common household chemical. The so-called octobot comprises a 1-mm-thick flexible silicone wafer set inside a molded soft body made of a squishy material. The wafer is crisscrossed with channels, like the conductive tracks on a computer circuit board, through which a 50% hydrogen peroxide solution flows. The hydrogen peroxide reacts with platinum in the channels to form oxygen gases, which expand and flow into the robot’s legs, causing them to flex. Although the octobot’s movements are restricted to wiggling extremities, the prototype serves as a proof of concept for more complex soft robots, which could serve various purposes such as squeezing into tight spaces.

Italy earthquake epicenter sits between those of two earlier quakes

25 August 2016
Nature: The number of people killed by Wednesday’s magnitude 6.2 earthquake in Italy has now risen to 247. It is the strongest earthquake to strike Italy since the magnitude 6.3 quake in 2009 near the town of L’Aquila, which killed about 300 people. The epicenters of both quakes lie in Italy’s Apennine mountain range, a seismically active area because of a major fault system that extends the entire length of the range. Seismologists had been expecting a rupture in the area where yesterday's earthquake occurred because of its location between the epicenters of two earlier quakes, the one in 2009 and another that occurred in 1997. However, unlike in 2009, there were no precursor tremors that might have indicated that the larger quake was coming.

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