JON CARTWRIGHT – Page 34 – & THREE QUARKS EDITORIAL

Unexpected ‘ridge’ seen in CMS collision data again

Physics WorldJon Cartwright31 October, 2012

Published in Physics World, 31 Oct 2012

The first data from proton–lead collisions at the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) at CERN include a “ridge” structure in correlations between newly generated particles. According to theorists in the US, the ridge may represent a new form of matter known as a “colour glass condensate”.

This is not the first time such correlations have been seen in collision remnants – in 2005, physicists working on the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory in New York found that the particles generated in collisions of gold nuclei had a tendency to spread transversely from the beam at very small relative angles, close to zero. A similar correlation was seen in 2010 at CMS in proton–proton collisions and then later that year in lead–lead collisions. (See image below, parts a and b.) […]

The rest of this article is available here.

Fracking to extract shale gas less water-intensive than Texan coal mining

Energy & EnvironmentJon Cartwright29 October, 2012

Published in ERW, 29 Oct 2012

A controversial method for extracting gas known as fracking consumes less freshwater than mining coal in Texas, according to a US study. The result goes against a claim of some of the method’s opponents, who had said that fracking was particularly water-intensive.

Fracking – or hydraulic fracturing, in full – to extract shale gas involves drilling a well between 1,500 and 3,000 metres deep before running a perforated steel pipe horizontally through a shale deposit. Millions of litres of water, as well as sand and chemicals, are then pumped into the pipe at high pressure, creating fractures in the (normally impermeable) shale around it. Natural gas can then flow from the shale into the pipe, from which the gas can be extracted. […]

The rest of this article is available here.

Clouds have ‘complex’ response to Sun’s changes

Energy & EnvironmentJon Cartwright25 October, 2012

Published in ERW, 25 Oct 2012

There is no straightforward relationship between cloud cover and solar variability, according to physicists in Europe who have searched for links over a 25-year period. The researchers say that solar effects are probably not visible globally, and should therefore be sought at a regional level in future studies.

The debate on the extent to which clouds are affected by solar variability – such as the 11-year-long solar cycle – has gone on for several decades. Clouds can cool regional climate, so if their overall long-term prevalence is affected by the Sun, that mechanism ought to be included in climate models. […]

The rest of this article is available here.

Analysing wind-turbine performance

Energy & EnvironmentJon Cartwright23 October, 2012

Published in ERW, 23 Oct 2012

Wind farms are becoming ever more prevalent: last year, the total world power capacity of turbines went up by about 20%. Nonetheless, it is difficult to predict exactly how well new turbines will perform in different atmospheric regimes. Manufacturers provide a “power curve”, which describes how power output should vary with wind speed, but this does not take into account irregular wind patterns such as wind shear and turbulence.

At some wind farms, particularly test sites, scientists place wind instruments – LIDAR and SODAR (laser and sound versions of radar) – to accurately measure how such wind patterns affect performance. But these instruments are expensive to install, and this leaves scientists with a shortage of data. The result is that it is difficult to know where to site, and how to arrange, future wind farms for the best power generation. […]

The rest of this article is available here.

El Niño more central since 1990

Energy & EnvironmentJon Cartwright18 October, 2012

Published in ERW, 18 Oct 2012

The last decade of the 20th century saw a major change in the relationship between the tropical and extra-tropical climate, according to scientists in the US and Taiwan. The discovery suggests that the increasing influence of the extra-tropical atmosphere on the tropical Pacific Ocean has driven the emergence of El Niño events in the central Pacific.

In recent years one of the most dramatic phenomena associated with climate change has been the shift of El Niño – a climate oscillation that occurs roughly every five years – from the east to the central Pacific. Scientists have begun to notice impacts resulting from the shift on weather patterns, marine biology and other parts of the ecosystem, yet the cause of the shift itself has been unknown. […]

The rest of this article is available here.

Moses Chan backtracks on search for supersolids

Physics WorldJon Cartwright16 October, 2012

Published in Physics World, 16 Oct 2012

In 2004 Moses Chan and his graduate student Eun-Seong Kim thought that they had made one of the most exciting condensed-matter discoveries of the new century. It was the supersolid – a mysterious substance that could float through ordinary solids, like a ghost through walls. Now the Penn State University physicist has published a paper arguing that his initial interpretation was wrong – a mundane materials effect rather than supersolidity was the cause of their anomalous experimental results. “It would have been nice if the supersolid [interpretation] was correct,” he says, “but Mother Nature had her own way.”

The paper comes after Chan and others struggled for eight years to produce conclusive evidence for the effect. Although the experiments have been a disappointment, they were not done on a whim. The supersolid concept has a long history and theoretical physicists – including Nobel laureate Philip Anderson – have developed compelling arguments for its existence. […]

The rest of this story is available here.

An ultralight graphene structure for all seasons

Chemistry WorldJon Cartwright12 October, 2012

Published in Chemistry World, 12 Oct 2012

Chemists in China claim to have created the lightest graphene framework to date. The material, which is light enough to rest on a dandelion seed head, is also fire resistant and has record-breaking adsorption and capacitance.

The development of ultralight materials has exploded in recent years. Last year, engineers in the US presented a material made of hollow metallic tubes in a micro-lattice. With a density of 0.9mg/cm³, the material was 100 times lighter than styrofoam. Yet that record was beaten in July, when material scientists in Germany produced what they called aerographite: a network of carbon microtubes with a density of just 0.2mg/cm³. […]

The rest of this article is available here.

Urban expansion can cause one degree of warming

Energy & EnvironmentJon Cartwright8 October, 2012

Published in ERW, 8 Oct 2012

Four decades of urban expansion alone can drive up regional temperatures by more than one degree, according to computer simulations performed in the US. The simulations, which examine various urban-expansion scenarios in Arizona up to 2050, also reveal that light-reflecting “cool roofs” are not a mitigation strategy free of pitfalls.

By 2050, according to the United Nations, there will be 2.6 billion more people living in cities. Scientists know that this urbanization will alter regional climate, even if the effect of climate change itself is neglected. One reason is that urban areas are “heat islands” compared with their rural counterparts: roads, paved areas and buildings retain heat, raising regional temperatures, particularly at night. In addition, there tends to be a greater number of anthropogenic sources of heat, such as air-conditioning units, in cities. […]

The rest of this article is available here.

A phased approach

Physics WorldJon Cartwright1 October, 2012

Published in Physics World, 1 Oct 2012

Now that the Square Kilometre Array will be split between sites in Australia and southern Africa, Jon Cartwright reports that some technological trickery will be needed to make the world’s biggest telescope work

While the discovery of the Higgs boson at CERN’s Large Hadron Collider (LHC) may have been taking all the headlines of late, there is some truth in claiming that the machine is already the “big science” of old. In just four years’ time, construction is slated to begin on a new project that will dwarf the Franco–Swiss particle accelerator by comparison. That project is the Square Kilometre Array (SKA) – the world’s biggest and most sensitive radio telescope.

Physically, SKA will be larger than the LHC, ultimately spreading over thousands of kilometres in Africa and Australasia. It will be made up of thousands of radio dishes and millions of radio antennas. To sort through the troves of data, it will need the fastest supercomputer on the planet. As Phil Diamond, who was appointed as the first director-general of SKA in September, points out: “It will be the largest science facility on Earth.” […]

For the rest of this article, please contact Jon Cartwright for a pdf.

Thermoelectrics ‘pass new milestone’

Chemistry WorldJon Cartwright19 September, 2012

Published in Chemistry World, 19 Sep 2012

Researchers in the US claim to have passed a new milestone in thermoelectrics with a material that converts heat to electricity more efficiently than ever before. The new thermoelectric material, which employs ‘panoscale’ structuring to scatter phonons, has a figure of merit (FoM) some 20% better than previously achieved.

Thermoelectrics convert heat to electricity and can, therefore, ‘harvest’ waste heat from the environment. When one end of a thermoelectric material is heated, electrons flow to the cooler side, creating a voltage across the material that can be tapped for electricity. […]

The rest of this article is available here.