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Scientists solve mystery of colorful armchair nanotubes

Rice University researchers have figured out what gives armchair nanotubes their unique bright colors: hydrogen-like objects called excitons.

Their findings appear in the online edition of the Journal of the American Chemical Society.

Armchair carbon nanotubes – so named for the "U"-shaped configuration of the atoms at their uncapped tips – are one-dimensional metals and have no band gap. This means electrons flow from one end to the other with little resistivity, the very property that may someday make armchair quantum wires possible.

Could Siberian volcanism have caused the Earth's largest extinction event?

Washington, D.C. — Around 250 million years ago, at the end of the Permian geologic period, there was a mass extinction so severe that it remains the most traumatic known species die-off in Earth's history. Although the cause of this event is a mystery, it has been speculated that the eruption of a large swath of volcanic rock in Russia called the Siberian Traps was a trigger for the extinction. New research from Carnegie's Linda Elkins-Tanton and her co-authors offers insight into how this volcanism could have contributed to drastic deterioration in the global environment of the period.

Smaller and more powerful electronics requires the understanding of 'quantum jamming' physics

New cores from glacier in the Eastern European Alps may yield new climate clues

COLUMBUS, Ohio – Researchers are beginning their analysis of what are probably the first successful ice cores drilled to bedrock from a glacier in the eastern European Alps.

With luck, that analysis will yield a record of past climate and environmental changes in the region for several centuries, and perhaps even covering the last 1,000 years. Scientists also hope that the core contains the remnants of early human activity in the region, such as the atmospheric byproducts of smelting metals.

New material for thermonuclear fusion reactors

Scientists at Universidad Carlos III de Madrid, Oxford University and the University of Michigan have joined efforts to develop new materials for thermonuclear fusion reactors. Their research focuses on characterization of oxide dispersion-strengthened, reduced-activation steel for the reactor structure.

Colorado mountain hail may disappear in a warmer future

Summertime hail could all but disappear from the eastern flank of Colorado's Rocky Mountains by 2070, according to a new modeling study by scientists from NOAA and several other institutions.

Less hail damage could be good news for gardeners and farmers, said Kelly Mahoney, Ph.D., lead author of the study and a postdoctoral scientist at NOAA's Earth System Research Laboratory in Boulder, Colo. But a shift from hail to rain can also mean more runoff, which could raise the risk of flash floods, she said.

Team finds a better way to gauge the climate costs of land use changes

CHAMPAIGN, Ill. — Those making land use decisions to reduce the harmful effects of climate change have focused almost exclusively on greenhouse gases – analyzing, for example, how much carbon dioxide is released when a forest is cleared to grow crops. A new study in Nature Climate Change aims to present a more complete picture – to incorporate other characteristics of ecosystems that also influence climate.

Graphene reveals its magnetic personality

In a report published in Nature Physics, they used graphene, the world's thinnest and strongest material, and made it magnetic.

Graphene is a sheet of carbon atoms arranged in a chicken wire structure. In its pristine state, it exhibits no signs of the conventional magnetism usually associated with such materials as iron or nickel.

Demonstrating its remarkable properties won Manchester researchers the Nobel Prize in Physics in 2010.

Global warming caused by greenhouse gases delays natural patterns of glaciation, researchers say

GAINESVILLE, Fla. --- Unprecedented levels of greenhouse gases in the Earth's atmosphere are disrupting normal patterns of glaciation, according to a study co-authored by a University of Florida researcher and published online Jan. 8 in Nature Geoscience.

The nuclear, biological and climate threat - 2011 reviewed

In this special issue of the Bulletin of the Atomic Scientists, published by SAGE, experts reflect on 2011 and highlight what to look out for in 2012 in the areas of nuclear energy, nuclear weapons, biosecurity, and climate change. Topics that have made the headlines during the previous 12 months, including the increased tension surrounding Iran's nuclear programme, the aftermath of the Fukushima incident, and the state of US policy on climate change, are analyzed in detail in this special issue.

Another outbreak of coral disease hits the reefs of Kane'ohe Bay, O'ahu

In March 2010 an outbreak of a disease called acute Montipora White Syndrome (MWS) was discovered affecting coral reefs in Kaneohe Bay, Oahu. Follow-up surveys found that the disease left trails of rubble in its wake. It was estimated that over 100 colonies of rice coral (Montipora capitata) died during that initial outbreak. The disease has reappeared and is killing corals in Kaneohe Bay. The current outbreak has already affected 198 colonies and a rapid response team led by Dr. Greta Aeby (HIMB) has been activated to document the outbreak.

Down to the wire for silicon: Researchers create a wire 4 atoms wide, 1 atom tall

WEST LAFAYETTE, Ind. - The smallest wires ever developed in silicon - just one atom tall and four atoms wide - have been shown by a team of researchers from the University of New South Wales, Melbourne University and Purdue University to have the same current-carrying capability as copper wires.

Experiments and atom-by-atom supercomputer models of the wires have found that the wires maintain a low capacity for resistance despite being more than 20 times thinner than conventional copper wires in microprocessors.

Down to the wire: Silicon links shrink to atomic scale

The narrowest conducting wires in silicon ever produced are shown to have the same electrical current carrying capability as copper, as published in Science.
This means electrical interconnects in silicon can be shrunk to the atomic-scale without losing their functionality – Ohm's law holds true at the atomic-scale.
UNSW researchers will use these wires to address individual atoms – a key step in realising a scalable quantum computer.

Graphene's piezoelectric promise

Graphene, the ultra-durable carbon material that holds promise for a range of applications, has yet another trick up its single-atom-thick sleeve. Engineers at the University of Houston have used quantum mechanical calculations to show that, merely by creating holes of a certain configuration in a sheet of graphene, they can coax graphene into behaving like a piezoelectric material.

Graphene rips follow rules

HOUSTON -- Research from Rice University and the University of California at Berkeley may give science and industry a new way to manipulate graphene, the wonder material expected to play a role in advanced electronic, mechanical and thermal applications.

When graphene – a one-atom thick sheet of carbon – rips under stress, it does so in a unique way that puzzled scientists who first observed the phenomenon. Instead of tearing randomly like a piece of paper would, it seeks the path of least resistance and creates new edges that give the material desirable qualities.