- Published on Wednesday, 08 October 2014 14:10
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 Thursday, 02 October 2014 15:48
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 Wednesday, 19 February 2014 14:02
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 Wednesday, 19 February 2014 09:08
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 Tuesday, 25 June 2013 12:00
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 Wednesday, 01 May 2013 21:22
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 Sunday, 10 February 2013 20:05
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 Saturday, 03 November 2012 17:35
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.
- Published on Sunday, 21 October 2012 15:31
Interdisciplinary Science with Cosmic Rays Guest Editors: Antonio Bueno and Lawrence Wiencke
The Pierre Auger Observatory, located near the base of the Argentinean Andes, is the largest cosmic ray facility in the world. Spanning 3,000 km2, its complementary detector systems use the troposphere as a giant calorimeter to measure the highest-energy subatomic particles known to mankind. Because this instrument observes both the earth and the cosmos in unique ways, its interdisciplinary significance extends to the atmospheric and earth sciences. The articles comprising this EPJ Plus Focus Point highlight examples of observations in these fields and discuss several beginning projects. As shown in the introductory remarks (A. Watson), these articles are intended to reach a broad audience, both in order to stimulate discussion and to encourage new collaborative efforts of an interdisciplinary nature.
The observatory is introduced by Wiencke et al. with examples such as a major earthquake that was observed by the observatory’s surface detector. A proposed seismic sensor array to be located at the observatory is also described by Ruigrok et al. The observatory’s ground-based atmospheric monitoring program is arguably the most extensive in the southern hemisphere. Aerosols and clouds play a complicated role in the earth’s climate and there are fewer detailed measurementsavailable from the southern hemisphere. The measurements of the atmospheric molecular component are described by Keilhauer et al., including a comparison between local radiosonde measurements and extrapolations from the Global Data Assimilation System. The subsequent article by Louedec et al. reviews methods used at the observatory to characterizeaerosols and atmospheric clarity, and outlines a proposed project to study the origin and transport of iron-rich aerosols that play a role in biological processes in the southern ocean. The article by Tonachini et al. discusses the lidar systems at the observatory. The demonstration how measurements of clouds are used to ground truth comparisons with GOES satellite datais the subject of the article by Chirinos et al. Next, Mussa et al. describe the serendipitous observation of transient luminescent events (ELVES) created above some thunderstorms. This article also demonstrates a detailed measurement of anELVE’s time evolution using the observatory’s air fluorescence detector. Finally, cosmic ray air showers have been proposed as a possible trigger mechanism for lightning. A closing article (Brown et al.) discusses a lightning detection system planned to test this hypothesis.
To view this focus point and others already published, please click here.
- Published on Sunday, 21 October 2012 15:19
Deep Underground Science Laboratories and Projects Guest Editor: Alessandro Bettini
Physicists have developed a theoretical description of the elementary building blocks of matter and of the basic forces of Nature, called the Standard Model. It is the most comprehensive theory ever developed and has been tested with high precision up to energies of a few hundred times the proton mass. A new collider, the LHC, has started to work at still higher energies, discovering the last missing element of the SM, the so-called Higgs boson. However we know already that this, and any accelerator of the future, will not be sufficient.
The reason is that three of the four basic forces of Nature, namely strong, electromagnetic and weak, seem to become equal at high energies. Unfortunately the energy scale of the unification is extremely high, so high that we will never be able to reach it with an accelerator. Even higher is the Planck scale, the Big Bang energy, at which, presumably, also the fourth force, gravitation, becomes unified. We can exploit an indirect way, because phenomena characterised by a high-energy scale do, in fact, happen naturally even at the lower, every day, energies. However the higher their intrinsic energy scale is, the more rarely they happen.
The deep underground laboratories are dedicated to the search for these natural, but extremely rare nuclear and subnuclear phenomena, requiring a very low radioactive background environment. The background is due to cosmic rays and to decays of radioactive nuclei present, in traces, in all materials. Underground laboratories, shielded from cosmic and radioactive radiations, have been built in Europe, Japan and North America. More are planned in China, India and South America. They differ in size, depth and organisation, but their scientific programmes are similar and complementary. Other disciplines, like geodynamics and biology, can profit from the unique environment of the underground facilities.
The author of the paper of each laboratory or project is the Director of the given Lab or the PI of the given project.
To view this focus point and others already published, please click here.