News
EPJ E Highlight - Levitating foam liquid under the spell of magnetic fields
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- Published on 06 November 2013
No better solution to studying ever-draining foams than applying a strong magnetic field to keep the liquid in the foam at a standstill by levitating its water molecules
Foams fascinate, partly due to their short lifespan. Foams change as fluid drains out of their structure over time. It is precisely their ephemeral nature which has, until now, prevented scientists from experimentally probing their characteristic dynamics further. Instead, foams have often been studied theoretically. Now, Nathan Isert from the University of Konstanz, Germany and colleagues, have devised a method of keeping foams in shape using a magnet, which allows their dynamics to be investigated experimentally, as recently described in EPJ E.
EPJ B Highlight - Numerical validation of quantum magnetic ordering
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- Published on 16 October 2013
Numerical simulations designed to confirm the magnetic characteristics of 3D quantum materials largely match the theoretical predictions
A new study set out to use numerical simulations to validate previous theoretical predictions describing materials exhibiting so-called antiferromagneting characteristics. A recently discovered theory shows that the ordering temperature depends on two factors—namely the spin-wave velocity and the staggered magnetisation. The results, largely consistent with these theoretical predictions, have now been published in a paper in EPJ B by Ming-Tso Kao and Fu-Jiun Jiang from the National Taiwan Normal University, in Taipei.
EPJ E Highlight - Uncovering liquid foams bubbly acoustics
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- Published on 14 October 2013
First study to shows specific sounds’ speed and attenuation characteristics in liquid foam, opens the door to new type of sound proofing material
Liquid foams fascinate toddlers singing in a bubble bath. Physicists, too, have an interest in their acoustical properties. Borrowing from both porous material and foam science, Juliette Pierre from the Paris Diderot University, Paris, France and her colleagues studied liquid foams. They used an impedance tube to measure the velocity and attenuation of acoustic waves in liquid foams in a broad frequency range. The study published in EPJ E is a first in the literature. It could help in assessing any liquid foam’s bubble size or in designing the optimal foam structure for sound proofing.
EPJ D Highlight - Uniformity: the secret of better fusion ignition
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- Published on 07 October 2013
Fusion is one of the holy grails of energy production. Now, theoretical physicists have used simulations to investigate the uniformity of irradiation at the ignition stage of thermonuclear fusion reaction.
One of the ways to achieve thermonuclear fusion is through a controlled reaction between two light variants of hydrogen, called deuterium and tritium. Mauro Temporal, from the École Normale Supérieure Cachan, in France, and colleagues have made theoretical calculations indicating how best to improve the ignition stage of fusion reaction. Their approach, described in a paper published in EPJ D, involves increasing the uniformity of irradiation using high-power laser beams on the external shell of a spherical capsule containing a mix of deuterium and tritium.
EPJ E Highlight - Understanding the evolution of lungs through physical principles
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- Published on 01 October 2013
How fluid dynamics and transport shaped the structure of our lungs in the course of evolution.
Two French physicists, Bernard Sapoval and Marcel Filoche from École Polytechnique in Palaiseau, France, suggest in a study published in EPJ E how evolution has shaped our lungs through successive optimisations of physical parameters such as conservation of energy and speed of delivery.
EPJ B Colloquium - Conjugated polymer-wrapped carbon nanotubes: physical properties and device applications
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- Published on 27 September 2013
This EPJ B Colloquium presents an overview of the preparation method and physical properties of a new hybrid system consisting of single-walled carbon nanotubes (SWNTs) wrapped in conjugated polymers. The technique, which was first demonstrated in 2007, has attracted great interest owing to the high purity of the resulting semiconducting SWNTs and the possibility of applying them in electronic devices. Here, the authors review recent progress in the preparation of these nano-hybrids, their photophysical properties, and their applications in field-effect transistors and photovoltaic devices.
EPJ D Colloquium - Modelling low energy electron and positron tracks in biologically relevant media
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- Published on 27 September 2013
This EPJD colloquium describes an approach whereby the effect of low and intermediate energy (0-100 eV) electrons and positrons can be incorporated into radiation damage models, in particular the deceleration of these particles in biologically-relevant materials (water and representative biomolecules). At the heart of the modelling procedure is a C++ computer program called Low Energy Particle Track Simulation (LEPTS), which is compatible with commonly available general purpose Monte Carlo packages. Input parameters are carefully selected from theoretical and experimental cross-section data and energy loss distribution functions.
EPJ E Highlight - Greater desertification control using sand trap simulations
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- Published on 25 September 2013
A new simulation will help improve artificial sand-control measures designed to help combat desertification by identifying their weaknesses
In the fight against desertification, so-called straw checkerboard barriers (SCB), consisting of half -exposed criss-crossing rows of straw of wheat, rice, reeds, and other plants, play a significant role. The trouble is that our understanding of the laws governing wind-sand movement in SCB and their surrounding area is insufficient. Now, Ning Huang and colleagues from Lanzhou University in China, have performed a numerical simulation of the sand movement inside the SCB, described in a paper just published in EPJ E. Their country is particularly affected by desertification, which affects 18% of its territory. The results will help us to understand sand fixation mechanisms that are relevant for sandstorm and land-desertification control.
EPJ B Highlight - Green photon beams more agile than optical tweezers
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- Published on 17 September 2013
A new manipulation tool exploits the fact that when light interacts with matter, it creates a force that produces material properties in macromolecules and biological cells
Romanian scientists have discovered a novel approach for the optical manipulation of macromolecules and biological cells. Their findings stem from challenging the idea that visible light would induce no physical effect on them since it is not absorbed. Instead, Sorin Comorosan, working as physicist at the National Institute for Physics and Nuclear Engineering based in Magurele, Romania, and as a biologist at the Fundeni Clinical Institute, Bucharest, Romania, and colleagues had the idea to use green photon beams. With them, it is possible to perform optical manipulation of macrostructures, such as biological proteins, with greater precision than with optical tweezers made from focused laser beams.
EPJ A Highlight - Prompt x-rays emitted in neutron-induced fission help unveil the evolution of fission fragment charge yields as a function of incident neutron energy
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- Published on 17 September 2013
Nuclear fission is accompanied by the prompt emission of neutrons, gamma rays and x-rays. It has been known since the sixties that fission prompt x-rays originate essentially as a consequence of the internal conversions occurring in the prompt gamma deexcitation cascades of fission fragments.
This work presents for the first time a measurement of the prompt fission x-ray yields in 238U(n,f) for average incident neutron energies ranging from 3 to 200 MeV. These results provide new information on fission fragment deexcitation and allow testing the current knowledge of fission fragment nuclear structure. These results provide also a means to investigate the evolution, as a function of incident neutron energy, of fission fragment charge yields and elemental prompt x-ray emission probabilities.
