- Published on 20 March 2019
Metashells can adapt their wave-bending behaviour based on the characteristics of the material they contain
A chameleon can flexibly change its colour to match its surroundings. And a similar phenomenon can now be seen in a new class of smart materials called metamaterials. The trouble is that these metamaterials lack the ability to respond to nearby objects due to their physical characteristics. To remedy this shortcoming, Chinese physicists have developed so-called 'metashells': hollow shells made of metamaterials and capable of carrying materials in their core. The advantage is that their physical characteristics, such as permittivity - the extent to which a material can store charge within an electrical field - change with the electromagnetic properties of the material they contain. In a recent theoretical study published in EPJ B, Liujun Xu and Jiping Huang from Fudan University in Shanghai, China, describe how they have developed an entire class of these chameleon-like metashells.
EPJ E Topical Review: Gyrotactic phytoplankton in laminar and turbulent ﬂows: A dynamical systems approach
- Published on 20 March 2019
Biological and geophysical fluids host a sea of microorganisms many of which are motile. An often overlooked aspect of the life of such microorganisms is that the fluids where they are suspended are not still but flowing. In this brief review published in EPJ E, the authors aim to describe some of the interesting phenomena that can emerge due to the modification of the microorganisms' swimming direction by velocity gradients, which affect both the individual motion of microorganisms and their spatial distribution in dilute suspensions.
EPJ Techniques and Instrumentation Highlight - Calibration samples to measure particle identification performance in the LHCb experiment
- Published on 05 March 2019
Deep underground in the Large Hadron Collider at CERN, beams of protons travel around in circles at almost the speed of light before they are collided head-on. These high-energy collisions produce large numbers of tiny, short-lived particles that quickly decay into lighter, more stable particles. Investigating these particle decays allows physicists to catch a glimpse of the early history of the universe. In new work published in EPJ Techniques and Instrumentation, Marianna Fontana and Donal Hill describe the method to create calibration samples that help determine the accuracy of the detector in the Large Hadron Collider beauty experiment in identifying different particles.
Read the guest post by Donal Hill & Marianna Fontana, originally published in the SpringerOpen blog.
- Published on 01 March 2019
Exotic non-spherical shapes of nuclear matter, so called pasta phases, are possible because of the competition between the short-ranged nuclear attraction and the long-ranged Coulomb repulsion, leading to the phenomenon of Coulomb frustration, well known in statistical mechanics. Such complex phases are expected in the inner crust of neutron stars, as well as in core-collapse supernova cores.
The authors of the EPJ A (2018) 54:215 paper examine for the first time the stability of the «lasagna» phase, consisting of periodically placed slabs, by means of exact geometrical methods. Calculations are done in the framework of the compressible liquid drop model but obtained results are universal and do not depend on model parameters like surface tension and charge density. The stability analysis is done with respect to the different types of deformations corresponding to the eigenvalues of the deformation matrix.
- Published on 18 February 2019
How much does someone's living room tell about how they live? Peeking into another person's life might be just part of natural human curiosity, but the answer to this question may provide insights in a wide range of aspects of human behavior. A new study published in EPJ Data Science uses the power of machine learning to explore patterns of home decors—and what they could tell about their owners—in popular accommodation website Airbnb.
- Published on 06 February 2019
Moving around small objects using capillary forces is a phenomenon that has stimulated scientists trying to understand the fundamental mechanisms at play. It is also important for many industrial, technological and analytical processes, for example micro-fluidics, oil and gas displacement, mineral flotation, miniature robot and biomechanics. In this EPJ E topical review article Jianlin Liu and Shanpeng Li present a critical review of capillarity-driven migration in which many examples are presented and explained. The small objects in question are non-deformable objects, such as particles, rods, disks and metal sheets as well as soft objects, such as droplets and bubbles. The authors clarify some misunderstandings on the conventional views on these systems.
- Published on 06 February 2019
Model explains the mechanisms of scraping negative ions from moving surfaces under a strong electric field
When cosmic rays collide with planets or debris, they lose energy. Scientists use the collision of electrons with a moving surface to simulate this process. A new study published in EPJ D provides a rudimentary model for simulating cosmic rays’ collisions with planets by looking at the model of electrons detached from a negative ion by photons. In this work, Chinese physicists have for the first time demonstrated that they can control the dynamics of negative ion detachment via photons, or photodetachment, on a moving surface.
EPJ Plus article on microﬁber pollution in the air selected for Springer Nature Grand Challenges Programme
- Published on 28 January 2019
A new study reports on microplastic fibres in the air, which can potentially enter the human body through breathing.
Microplastics (MPs) are one of the major hot topics in environmental science. Scientists have started to investigate the impact of such pollutants in different habitats, such as oceans, rivers, soils and air. Several studies have shown that MP fibers are very common in the atmosphere. They are invisible to human eye as they are smaller than 5 mm. These fibers, which derive from different sources, float freely in the air pushed by winds. A recent study, published on EPJ Plus, evaluated microfiber pollution in the air of an intercity terminal and a university campus in the Sakarya Province, Turkey.
- Published on 25 January 2019
A new study proposes a new way of ranking universities, using a more balanced cultural view and based on 24 international editions of Wikipedia
Scientists in France have developed a new way of generating a ranking of the world’s universities that places more emphasis on the cultural perspective. In a recent study published in EPJ B, Célestin Coquidé and José Lages, affiliated with the multidisciplinary research institute UTINAM in Besançon, and Dima Shepelyansky from the CNRS in Toulouse, France, perform an analysis of Wikipedia editions in 24 languages, collected in May 2017 - previous studies pursuing a similar approach focused on data from 2013. Employing well-known ranking algorithms, they establish a Wikipedia Ranking of World Universities based on the relative cultural views of each of the 24 language-specific Wikipedia editions. Thus, they provide a more balanced view that reflects the standpoints of different cultures.
- Published on 23 January 2019
Study improves the lower boundary and secret key capacity of an encryption channel
The secure encryption of information units based on a method called quantum key distribution (QKD) involves distributing secret keys between two parties - namely, Alice, the sender, and Bob, the receiver - by using quantum systems as information carriers. However, the most advanced quantum technology, QKD, is currently limited by the channel's capacity to send or share secret bits. In a recent study published in EPJ D, Gan Wang, who is affiliated with both Peking University, Bejing, China, and the University of York, UK, and colleagues show how to better approach the secret key capacity by improving the channel's lower boundary.