EPJ Plus Highlight - An efficient Lattice-Boltzmann approach for studying compressible flow in nonlinear thermoacoustic engines
- Published on 16 February 2015
Thermoacoustics is the physics of the interaction of thermal and acoustic fields. The nonlinear acoustic effect and low Mach number compressible flow in thermoacoustic engines make the theoretical analysis of such systems extremely complicated. A new study investigates the nonlinear self-excited thermoacoustic onset in a Rijke tube via the lattice Boltzmann method (LBM), which simulates the fluid flow by tracking the evolution of particles and obtains flow stream and heat transfer patterns from the kinetic level. The adopted LBM model, which was developed by the authors, convincingly simulates the Navier-Stokes-Fourier equations, treating accurately the nonlinear process of wave excitation of coupled fields and providing reliable estimates for pressure, density, velocity and temperature in such a finite geometry.
- Published on 10 February 2015
Solar-cell efficiency depends on how thin it can be manufactured. Now, a new model exploits femtosecond laser sources to get higher efficiency at lower cost
The race for ever more efficient and cheaper solar cells tests the limits of manufacturing. To achieve this, photovoltaic solar cells need to become thinner and are made of more complex inner structures. Now, Italian scientists have investigated and expanded a model elucidating the dominant physical processes when ultra-fast lasers are used in manufacturing solar cells to these specifications. An article by Alberto Gurizzan and Paolo Villoresi from the University of Padova in Italy detailing this model has now been published in EPJ Plus.
- Published on 08 October 2014
How does an electric (or magnetic) dipole behave in an electromagnetic field, when its velocity becomes comparable with the speed of light?
This problem has been solved for the first time in a paper recently published in EPJ Plus, where novel relativistic effects were found. In particular, it has been shown that the concept of “hidden” momentum of magnetic dipoles in an electric field, being disputable up to date, is strongly required to derive relativistically adequate solutions. Moreover, a novel concept of “latent” momentum of electric dipole should be also involved into the description of dipoles.
- Published on 02 October 2014
Simulating the cost of generating a combination of electricity sources while accounting for the fluctuating nature of energy production and demand provides tools to optimise such energy mix
Increasing reliance on renewable energies is the way to achieve greater CO2 emission sustainability and energy independence. Yet, because such energies are only available intermittently and energy cannot be stored easily, most countries aim to combine several energy sources. Now, in a new study in EPJ Plus, French scientists have come up with an open source simulation method to calculate the actual cost of relying on a combination of electricity sources. Bernard Bonin from the Atomic Energy Research Centre CEA Saclay, France, and colleagues demonstrate that cost is not directly proportional to the demand level. Although recognised as crude by its creator, this method can be tailored to account for the public’s interest—and not solely economic performance—when optimising the energy mix.
- Published on 19 February 2014
Physicists use carbon dating to confirm alleged Fernand Léger painting was definitely a fake, thus corroborating the doubts about its authenticity previously expressed by art historians
Choosing the right physical technique to analyse paintings can make all the difference when it comes to ascertaining their authenticity. Now, a painting initially attributed as belonging to a series called ‘Contraste de formes’ by French Cubist painter Fernand Léger has definitely been identified as a forgery. This is the first time it has been possible to identify a fake painting by relying on the anomalous behaviour of the concentration of the radioactive form of carbon (14C) in the atmosphere after 1955 to date the canvas. These findings were recently published in EPJ Plus by Mariaelenea Fedi of the National Institute of Nuclear Physics (INFN) in Florence, Italy, and colleagues.
- Published on 19 February 2014
A new study focuses on the feasibility of scaling up renewable energy to cover the needs of a country the size of Germany
Can renewable energy adequately supply the power grid, despite its intermittent nature? This is the key question in a new study published in EPJ Plus. The study is based on an analysis of concrete data from 2012 for the German national grid, which also utilises electricity from both on and offshore wind (8%) and solar sources (4.8%). Friedrich Wagner from the Max-Planck Institute for Plasma Physics in Greifswald, Germany, outlines the key issues associated with the use of renewable energy on a large scale.
- Published on 25 June 2013
The release of the journal Impact Factors (IF) by Thomson Reuters confirms once more the position of EPJ as a premium provider of relevant and strictly peer-reviewed research in the physical sciences and beyond. We are especially proud of the fast-paced development of our newer journals: EPJ Plus, launched only in 2011, was already awarded its first IF (1.302) and EPJ H – Historical Perspectives in Contemporary Physics, launched in 2010, progressed from an IF of 1.182 in 2011 to an impressive 2.375 for 2012.
The full overview of 2012 EPJ Impact Factors is given here.
- Published on 01 May 2013
EPJ Plus welcomes Eugenio Nappi as co-Editor in Chief, alongside Luisa Cifarelli. Nappi is Director of Research at INFN, the Italian Istituto Nazionale di Fisica Nucleare. He is an experimental particle physicist who has carried out most of his research activities at CERN and DESY.
His main research interests include the study of heavy nucleus collisions at ultrarelativistic energies with the ALICE Experiment at LHC, where he held the highest managerial positions. In 2000, he became project leader of the Cherenkov system, named HMPID, the largest CsI Ring Imaging Cherenkov (RICH) detector ever built. In the same year he joined the HERMES experiment at HERA-DESY. In HERMES, he spearheaded the design of the first-ever aerogel radiator RICH detector. More recently, he has become interested in medical imaging and joined the AXPET collaboration at CERN, which is intended to develop a new concept for Positron Emission Tomography (PET).
Author of more than 250 peer-reviewed papers, he is a member of the Executive Board of INFN, the ICFA Panel on Instrumentation, the CST of CNRS-IPN Orsay, the ECE (Expert Committee for the Experiments) of FAIR and the STC (Steering Committee) OF ESS (European Spallation Source).
- Published on 10 February 2013
What can go wrong when computer simulations are applied outside their original context
In an article just published in EPJ Plus, Daan Frenkel from the University of Cambridge, UK, outlines the many pitfalls associated with simulation methods such as Monte Carlo algorithms or other commonly used molecular dynamics approaches.
The context of this paper is the exponential development of computing power in the past 60 years, estimated to have increased by a factor of 1015, in line with Moore’s law. Today, short simulations can reproduce a system the size of a bacterium.
- Published on 03 November 2012
The discovery of the accelerating expansion of the Universe, thought to be driven by a mysterious form of ‘dark energy’ constituting most of the Universe, has further revived the interest in testing Einstein’s theory of General Relativity (GR). Frame-dragging in the gravitational field generated by a rotating body or by a current of mass-energy is one of the most fascinating phenomena predicted by GR. The recently launched LARES (Laser RElativity Satellite) space mission is aimed at improving of about an order of magnitude the accuracy of the previous frame-dragging measurements by the LAGEOS and LAGEOS 2 satellites, using GRACE-derived Earth gravity determinations. After some years of orbital analysis of LARES, LAGEOS and LAGEOS 2 satellite laser ranging data, we should reach a few percent uncertainty in testing frame-dragging.