Earth

Scientists capture first direct proof of Hofstadter butterfly effect

A team of researchers from several universities – including UCF –has observed a rare quantum physics effect that produces a repeating butterfly-shaped energy spectrum in a magnetic field, confirming the longstanding prediction of the quantum fractal energy structure called Hofstadter's butterfly.

This discovery by the team paves the way for engineering new types of extraordinary nanoscale materials that can be used to develop smaller, lighter and faster electronics, including sensors, cell phones, tablets and laptops.

3-D modeling technology offers groundbreaking solution for engineers

Software developed at the University of Sheffield has the potential to enable engineers to make 'real world' safety assessments of structures and foundations with unprecedented ease.

Developed in the Department of Civil & Structural Engineering, the software can directly identify three-dimensional collapse mechanisms and provide information about margin of safety, vitally important to engineers.

Study reveals scientific consensus on anthropogenic climate change

A comprehensive analysis of peer-reviewed articles on the topic of global warming and climate change has revealed an overwhelming consensus among scientists that recent warming is human-caused.

The study is the most comprehensive yet and identified 4000 summaries, otherwise known as abstracts, from papers published in the past 21 years that stated a position on the cause of recent global warming – 97 per cent of these endorsed the consensus that we are seeing man-made, or anthropogenic, global warming (AGW)

UC Santa Barbara scientist studies methane levels in cross-continent drive

(Santa Barbara, Calif.) –– After taking a rented camper outfitted with special equipment to measure methane on a cross-continent drive, a UC Santa Barbara scientist has found that methane emissions across large parts of the U.S. are higher than currently known, confirming what other more local studies have found. Their research is published in the journal Atmospheric Environment.

Never-before-seen energy pattern observed at National High Magnetic Field Laboratory

TALLAHASSEE, Fla. Two research teams at the National High Magnetic Field Laboratory (MagLab) broke through a nearly 40-year barrier recently when they observed a never-before-seen energy pattern.

The butterfly-shaped pattern was first theorized by physicist Douglas Hofstadter in 1976, but it took the tools and technology now available at the MagLab to prove its existence.

Emotional response to climate change influences whether we seek or avoid further information

BUFFALO, N.Y. – Sixty-two percent of Americans now say they believe that global warming is happening, but 46 percent say they are "very sure" or "extremely sure" that it is not. Only 49 percent know why it is occurring, and about as many say they're not worried about it, according to the April report of the Yale Project on Climate Change Communication.

RUB physicists let magnetic dipoles interact on the nanoscale for the first time

Physicists at the Ruhr-Universität Bochum (RUB) have found out how tiny islands of magnetic material align themselves when sorted on a regular lattice - by measurements at BESSY II. Contrary to expectations, the north and south poles of the magnetic islands did not arrange themselves in a zigzag pattern, but in chains. "The understanding of the driving interactions is of great technological interest for future hard disk drives, which are composed of small magnetic islands", says Prof. Dr. Hartmut Zabel of the Chair of Experimental Physics / Solid State Physics at the RUB.

Catching graphene butterflies

Writing in Nature, a large international team led Dr Roman Gorbachev from The University of Manchester shows that, when graphene placed on top of insulating boron nitride, or 'white graphene', the electronic properties of graphene change dramatically revealing a pattern resembling a butterfly.

The pattern is referred to as the elusive Hofstadter butterfly that has been known in theory for many decades but never before observed in experiments.

First direct proof of Hofstadter butterfly fractal observed in moiré superlattices

New York, NY—May 15, 2013—A team of researchers from Columbia University, City University of New York, the University of Central Florida (UCF), and Tohoku University and the National Institute for Materials Science in Japan, have directly observed a rare quantum effect that produces a repeating butterfly-shaped energy spectrum, confirming the longstanding prediction of this quantum fractal energy structure, called Hofstadter's butterfly. The study, which focused on moiré-patterned graphene, is published in the May 15, 2013, Advance Online Publication (AOP) of Nature.

Observation of second sound in a quantum gas

Below a critical temperature, certain fluids become superfluid and lose internal friction. In addition, fluids in this state conduct heat extremely efficiently, with energy transport occurring in a distinct temperature wave. Because of the similarities to a sound wave, this temperature wave is also called second sound. To explain the nature of superfluids, the famous physicist Lev Landau developed the theory of two-fluid hydrodynamics in Moscow in 1941.

Fall warming on Antarctic Peninsula driven by tropically forced circulation

The eastern side of the Antarctic Peninsula, a finger of the southern polar continent that juts toward South America, has experienced summer warming of perhaps a half-degree per decade – a greater rate than possibly anywhere else on Earth – in the last 50 years, and that warming is largely attributed to human causes.

Terracotta and cement roofs vulnerable in wildfires, NIST study finds

Although made of fire-resistant materials, terracotta and cement roof tiles are vulnerable to penetration by windblown embers generated in wildfires, according to new research findings* from the National Institute of Standards and Technology (NIST).

In scoping experiments conducted in the Fire Research Wind Tunnel Facility at Japan's Building Research Institute, NIST fire scientist Samuel Manzello found that the embers—or firebrands—infiltrated gaps between certain types of roofing tiles and, once trapped, proceeded to melt the underlayment below.

European Research Infrastructures help to solve air quality issues

Brussels. Scientists have advocated for tightening the Air Quality Directive and expand research on air quality and climate change. Only appropriate investments in research can provide a solid basis for decision making in these areas that have major health and economic consequences for Europe's citizens. In 2013, the European Commission's air policy is reviewed, with a focus on finding ways to improve the quality of the air Europeans breathe.

Groundwater unaffected by shale gas production in Arkansas

DURHAM, N.C. -- A new study by scientists at Duke University and the U.S. Geological Survey (USGS) finds no evidence of groundwater contamination from shale gas production in Arkansas.

"Our results show no discernible impairment of groundwater quality in areas associated with natural gas drilling and hydraulic fracturing in this region," said Avner Vengosh, professor of geochemistry and water quality at Duke's Nicholas School of the Environment.

European winter weather harder to forecast in certain years

Weather forecasters have a tougher job predicting winter conditions over Europe in some years over others, concludes a new study carried out by the National Oceanography Centre.

The study revealed that the relationship between our winter weather and the strength of the airflow coming in from the Atlantic – one of the factors used by forecasters to predict the weather – is stronger in some years than others. The results were recently published in the Royal Meteorological Society publication Weather.