For the last century, the concept of crystals has been a mainstay of solid-state physics. Crystals are paragons of order; crystalline materials are defined by the repeating patterns their constituent atoms and molecules make.
Now physicists at the University of Pennsylvania and the University of Chicago have evidence that a new concept should undergird our understanding of most materials: the anticrystal, a theoretical solid that is completely disordered.
Techniques for controlling ultra-cold atoms travelling in ring traps currently represent an important research area in physics. A new study gives a proof of principle, confirmed by numerical simulations, of the applicability to ultra-cold atoms of a very efficient and robust transport technique called spatial adiabatic passage (SAP). Yu Loiko from the University of Barcelona, Spain, and colleagues have, for the first time, applied SAP to inject, extract, and filter the velocity of neutral atoms from and into a ring trap.
New research shows projected changes in the winds circling the Antarctic may accelerate global sea level rise significantly more than previously estimated.
Changes to Antarctic winds have already been linked to southern Australia's drying climate but now it appears they may also have a profound impact on warming ocean temperatures under the ice shelves along the coastline of West and East Antarctic.
RENO – Every year, wildfires clear millions of hectares of land and emit around 34-percent of global soot mass into the atmosphere. In certain regions, such as Southeast Asia and Russia, these fires can contribute as much as 63-percent of regional soot mass.
The PandaX experiment of China, which is located in the deepest underground laboratory, has released its technical design report recently. The full article will appear in SCIENCE CHINA Physics, Mechanics & Astronomy, 2014, 57(8): 1476-1494.
The equivalent of one-third of Melbourne's water use could be saved each year through the implementation of efficiency measures that deal with climate change, according to a new study.
Researchers at the Monash Sustainability Institute analysed the water-saving potential of 74 options for reducing greenhouse gas emissions identified in ClimateWorks Australia's award-winning Low Carbon Growth Plan for Australia. The research was published this week in Springer's international journal Climatic Change.
Boulder, Colo., USA – A trio of paleontologists has discovered a remarkable new tracksite in Alaska's Denali National Park filled with duck-billed dinosaur footprints -- technically referred to as hadrosaurs -- that demonstrates they not only lived in multi-generational herds but thrived in the ancient high-latitude, polar ecosystem. The paper provides new insight into the herd structure and paleobiology of northern polar dinosaurs in an arctic greenhouse world.
Introducing graphene
One of the hottest materials in condensed matter research today is graphene.
Graphene had an unlikely start: it began with researchers messing around with pencil marks on paper. Pencil "lead" is actually made of graphite, which is a soft crystal lattice made of nothing but carbon atoms. When pencils deposit that graphite on paper, the lattice is laid down in thin sheets. By pulling that lattice apart into thinner sheets – originally using Scotch tape – researchers discovered that they could make flakes of crystal just one atom thick.
ITHACA, N.Y. – The dramatic increase in earthquakes in central Oklahoma since 2009 is likely attributable to subsurface wastewater injection at just a handful of disposal wells, finds a new study to be published in the journal Science on July 3, 2014.
The research team was led by Katie Keranen, professor of geophysics at Cornell University, who says Oklahoma earthquakes constitute nearly half of all central and eastern U.S. seismicity from 2008 to 2013, many occurring in areas of high-rate water disposal.
Columbia researchers have observed the fractional quantum Hall effect in bilayer graphene and shown that this exotic state of matter can be tuned by an electric field.
MILWAUKEE – Using graphene ribbons of unimaginably small widths – just several atoms across – a group of researchers at the University of Wisconsin-Milwaukee (UWM) has found a novel way to "tune" the wonder material, causing the extremely efficient conductor of electricity to act as a semiconductor.
In principle, their method for producing these narrow ribbons – at a width roughly equal to the diameter of a strand of human DNA – and manipulating the ribbons' electrical conductivity could be used to produce nano-devices.
Tropical Storm Douglas is on a weakening trend, according to the National Hurricane Center, and satellite imagery showed that the storm appeared more elongated on July 3.
NOAA's Geostationary Operational Environmental Satellite or GOES-West satellite captured visible data on Douglas just after sunrise on July 3 at 13:15 UTC (9:15 a.m. EDT). The data from GOES-West was made into an image at NASA/NOAA's GOES Project at the NASA Goddard Space Flight Center in Greenbelt, Md.
Tree frogs reach great heights with their jumps, but do not cover much distance.
(Photo Credit: Marta Vidal-Garcia)
Burrowing frogs have short limbs and squat bodies, restricting their jumping ability.
(Photo Credit: Marta Vidal-Garcia)
Source: Society for Experimental Biology
Iron is present in tiny concentrations in seawater. On the order of a few billionths of a gram in a liter.
"I did a calculation once on a ton of ocean water," says Seth John, an assistant professor in the department of marine science at the University of South Carolina. "The amount of iron in that ton of water would weigh about as much as a single eyelash."
Given that there is so little iron in seawater, one might conclude that its presence there is inconsequential.
The July feature of Science Elements, the American Chemical Society's (ACS') weekly podcast series, shines the spotlight on the science of fireworks, just in time for the July 4th holiday. The episode is available at http://www.acs.org/scienceelements.