JON CARTWRIGHT – Page 39 – & THREE QUARKS EDITORIAL

Watching the double-slit experiment in real time

Chemistry WorldJon Cartwright26 March, 2012

Published in Chemistry World, 26 Mar 2012

Richard Feynman, one of the 20th century’s greatest physicists, once said the double-slit experiment went to ‘the heart of quantum mechanics’. Now, an international team of scientists has refined the famous experiment, allowing the untrained observer to watch it unfold in real time.

To understand the basics of the double-slit experiment, imagine firing solid particles at a wall containing two narrow gaps: at some distance on the other side, the particles amass in two piles. Now imagine sending water waves at the wall. Instead of two ‘piles’ of water forming, the waves interfere with each other, producing a complex array of peaks and troughs. It is this difference in pattern – a complex array of peaks and troughs compared with just two peaks – that classically distinguishes waves from particles. […]

The rest of this article is available here.

‘Antimagnet’ renders magnets invisible

NatureJon Cartwright22 March, 2012

Published in Nature, 22 Mar 2012

Physicists have already unveiled invisibility cloaks that can hide objects from light, sound, seismic and even water waves. Now researchers report a cloak that can hide objects from static magnetic fields. This ‘antimagnet’ could have medical applications, but might also subvert airport security.

Writing in Science, a team of theorists led by Alvaro Sanchez at the Autonomous University of Barcelona in Spain, together with experimentalists at the Slovak Academy of Sciences in Bratislava, describe a magnetic cloak made with inexpensive, readily available materials. […]

The rest of this article is available here.

DVD player burns graphene to disc

Chemistry WorldJon Cartwright15 March, 2012

Published in Chemistry World, 15 Mar 2012

Producing a highly sought wonder material can be as easy as burning a DVD. That is according to chemists in the US, who have used a standard DVD player to reduce films of graphite oxide to graphene. These graphene films can be made into high-performance, flexible capacitors fit for bendy solar cells or roll-up displays.

A lot of current research is focused on producing high-performance capacitors for energy storage. Electrochemical capacitors, otherwise known as supercapacitors, have some promising attributes – they can undergo frequent charge and discharge cycles, for instance – but in general they are still limited by low energy and power densities. Higher energy densities would enable devices to run longer, while higher power densities would enable them to run faster. […]

The rest of this article is available here.

Dineutron emission seen for the first time

Physics WorldJon Cartwright14 March, 2012

Published in Physics World, 14 Mar 2012

Physicists in the US claim to have witnessed, for the first time, the emission of a neutron pair in the decay of an atomic nucleus. Such “dineutron” decay could extend our understanding of the strong force, which is responsible for holding nuclei together, and the processes taking place in neutron stars.

Nuclear decay occurs when atoms change form in order to become more stable. The best known types are alpha decay, in which a helium nucleus is emitted, beta decay, in which an electron or positron is emitted, and gamma decay, in which gamma rays are emitted. In addition to these are decays involving the emission of a single proton or a single neutron. […]

The rest of this article is available here.

Killer crystals turn pyroelectricity on bacteria

Chemistry WorldJon Cartwright7 March, 2012

Published in Chemistry World, 7 Mar 2012

Crystals of lithium niobate and lithium tantalate powdered and formulated as nanoparticles can act as a disinfectant, killing bacteria at only moderate temperatures, according to researchers in Germany. The crystal powders, which convert warmth into electrical energy and then chemical energy via the pyroelectric effect, could one day be used to disinfect air or water using just heat from the powder’s surroundings.

Recent years have seen a rising demand for simple and cheap disinfection methods, partly to address world health problems and partly to put less strain on the environment. One new method is to use high, pulsed electric fields to kill microorganisms. Another relies on oxygen-based semiconductors, such as titanium dioxide, which form reactive, bacteria-killing oxygen species on exposure to light. Such semiconductors have already been applied to specialist windows, which can then self-clean in the daytime. […]

The rest of this article is available here.

Settling the fracking question

Physics WorldJon Cartwright1 March, 2012

Published in Physics World, 1 Mar 2012

Energy firms have not convinced sceptics that shale-gas extraction, or “fracking”, is safe for the environment. Jon Cartwright examines whether physics could help

Hydraulic fracturing, or “fracking”, is by any measure controversial. The process – which involves pumping sand and liquid into deep shale deposits to liberate natural gas – has been touted by its proponents as an energy saviour. For them, fracking allows energy companies to tap into reserves that are otherwise difficult, if not impossible, to get gas from. Yet the process has been slammed by opponents as being hugely damaging to the environment.

While fracking has taken off rapidly in the US, it has been banned in France and Bulgaria. Unfortunately, this polarized debate about fracking is not helped by a shortage of facts. No-one is sure to what extent fracking can contaminate groundwater, either with methane or with toxic chemicals. There is also a concern that fracking can trigger moderate earthquakes. While there may be no hard-and-fast answers, it seems that geophysics may be able to prod the debate in a constructive direction. […]

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

Graphyne Could Be Better Than Graphene

ScienceJon Cartwright1 March, 2012

Published in ScienceNow, 1 Mar 2012

Graphene, a layer of graphite just one atom thick, isn’t called a wonder material for nothing. The subject of the 2010 Nobel Prize in physics, it is famed for its superlative mechanical and electronic properties. Yet new computer simulations suggest that the electronic properties of a little-known sister material of graphene—graphyne—may in some ways be better.

The simulations show that graphyne’s conduction electrons should travel extremely fast—as they do in graphene—but in only one direction. That property could help researchers design faster transistors and other electronic components that process one-way current, says one of the study’s authors, theoretical chemist Andreas Görling of the University of Erlangen-Nuremberg in Germany. “If your material already conducts in one direction, you have a head start,” he says. […]

The rest of this article is available here.

Evidence for Antimatter Anomaly Mounts

ScienceJon Cartwright29 February, 2012

Published in ScienceNOW, 29 Feb 2012

The big bang created a lot of matter—along with the same amount of antimatter, which wiped out everything and brought the universe to an untimely end. That’s what accepted theoretical physics tell us—though things clearly didn’t work out that way. Now, results from a U.S. particle smasher are providing new evidence for a subtle difference in the properties of matter and antimatter that may explain how the early universe survived.

The first evidence of a difference between matter and antimatter was found in the 1960s in the decay of particles called neutral kaons, which led to the awarding of a Nobel Prize in physics. In 2001, accelerators in the United States and Japan found more evidence for a difference in particles called B mesons. Then last year at CERN’s Large Hadron Collider (LHC) near Geneva, Switzerland, evidence was found in a third system, D mesons, but there wasn’t enough data to rule out a statistical fluke. The new results—which come from the Collider Detector at Fermilab (CDF) experiment near Chicago—are still not conclusive evidence, but they bring the chances of a fluke down to about one in 10,000. “I’m sure in a few days everyone in the field will feel much more confident that this is actually real,” says Giovanni Punzi, spokesperson of the CDF experiment. […]

The rest of this article is available here.

Lab study could aid inkjet printing

Physics WorldJon Cartwright22 February, 2012

Published in Physics World, 22 Feb 2012

A filament of liquid squirted from a nozzle will sometimes contract into a single drop and other times break up into many segments. Now, researchers in the UK have mapped the parameters that will lead a filament to break up, and they believe that this knowledge could help in the design of inkjet printers.

Inkjet printing requires single drops of ink to be deposited on paper, and for this reason engineers are keen to avoid conditions that would encourage ink filaments squirted from an inkjet nozzle to break up. Theory shows that there are several crucial parameters: the liquid’s density, viscosity and surface tension – all three of which can be grouped into a single “Ohnesorge number”. The other is the aspect ratio, which describes the filaments’ length in relation to diameter. In general, longer filaments with a high aspect ratio, and filaments with a small Ohnesorge number, are likely to break up. […]

The rest of this article is available here.

DNA nanorobots seek and destroy disease

Chemistry WorldJon Cartwright17 February, 2012

Published in Chemistry World, 17 Feb 2012

Researchers in the US have created a DNA-based nanorobot that can work its way through cell cultures, delivering cargo only at specific targets. The development could pave the way for programmable therapeutics, in which nanorobots would provide medical treatment only to certain types of cell or tissue.

The field of nanomachines has taken off in recent years, mostly thanks to so-called DNA origami. In this technique, DNA strands can be folded controllably into a structure, onto which different molecules can be attached. Researchers have already shown that structures built using DNA origami can perform basic robotic tasks, such as sensing, computation and targeting cells. But, says biophysicist Shawn Douglas at Harvard Medical School in Boston, Massachusetts, no one has ever combined these tasks to do something more sophisticated, such as cell-targeted cargo delivery. […]

The rest of this article is available here.