- Published on Friday, 17 March 2017 13:24
Delivery of biochemical substances is now possible using a novel application of liquid crystal defects, forming a loop enclosing the substance travelling alongside twisted fibres
Defects that break the symmetry of otherwise orderly material are called topological defects. In solid crystals, they are called dislocations because they interrupt the regularly structured atom lattice. In contrast, topological defects called disclinations take the form of loops in liquid crystal of the nematic variety, whose elongated molecules look like a shoal of fish. New experiments supported by a theoretical model show how defects forming loops around twisted plastic fibres dipped in liquid crystal could be used for the transport of biochemical substances, when controlled by electric and magnetic fields. Published in EPJ E, these findings - achieved by Mallory Dazza from the Ecole normale supérieure Cachan, France, and colleagues - have potential applications in electro-optical micromechanical and microfluidic systems.
- Published on Tuesday, 14 March 2017 13:52
“Winning is not a sometime thing; it’s an all the time thing. Winning is a habit,” said legendary American football coach Vince Lombardi.
Human sports and games, with their rules of competition and measures of performance, serve as an ideal test-bed to look for universal features of hierarchy formation. In a recent article published in EPJ Data Science, José A. Morales and colleagues study the behaviour of performance rankings over time of players and teams for several sports and games, and find statistical regularities in the dynamics of ranks. This finding dispels the commonly held notion that rank changes are due to the intrinsic strengths or qualities of teams and players. The same phenomenon may apply to more complex competition settings with further examinations.
- Published on Tuesday, 07 March 2017 17:36
Physicists define a smart way of inducing large-amplitude vibrations in graphene models, which could open the door for novel electronic applications
Graphene, the one-atom-thick material made of carbon atoms, still holds some unexplained qualities, which are important in connection with electronic applications where high-conductivity matters, ranging from smart materials that collectively respond to external stimuli in a coherent, tunable fashion, to light-induced, all-optical networks. Materials like graphene can exhibit a particular type of large-amplitude, stable vibrational modes that are localised, referred to as Discrete Breathers (DBs). The secret to enhancing conductivity by creating DBs lies in creating the external constraints to make atoms within the material oscillate perpendicular to the direction of the graphene sheet. Simulations-based models describing what happens at the atomic level are not straightforward, making it necessary to determine the initial conditions leading to the emergence of DBs. In a new paper published in EPJ B, Elham Barani from the Ferdowsi University of Mashhad, Iran, and colleagues from Russia, Iran and Singapore use a systematic approach to identify the initial conditions that lend themselves to exciting DBs in graphene, ultimately opening the door to understanding the keys to greater conductivity.
- Published on Wednesday, 01 March 2017 17:27
Physicists elucidate the effects of light rays falling onto hydrogen atoms trapped in a carbon atom cage
Light interacting with hydrogen atoms enclosed in hollow cages composed of carbon atoms - referred to as fullerene material - produces ionisation. This phenomenon, which has been the subject of intense theoretical scrutiny, is particularly interesting because the light rays can have dramatic effects in inducing small external energy potentials. Specifically, they alter the structural and dynamic properties of the atoms confined within the fullerene molecule. Ana Frapiccini from the CONICET research centre at the Universidad Nacional del Sur, in Bahía Blanca, Argentina, and colleagues have just published a study in EPJ D explaining the theory behind the ionisation. Applications of this process include drug delivery, quantum computation, photovoltaics and hydrogen storage.
EPJ E Review - Water and ionic liquids. Two very different solvents, two intriguing behaviours when nanoconfined
- Published on Tuesday, 28 February 2017 09:57
Confinement of liquids at the nanoscale gives rise to intriguing new chemical and physical behaviours and structures. Scientists are studying the phenomenon also because of its relevance to molecular biology (permeability of ion channels and protein stability), chemical engineering (nano-fluidic devices and molecular sieves) and geology (transport through porous rocks).
- Published on Monday, 27 February 2017 17:19
Guest Editors: G. Alimonti, S. Johansson and L. Mariani
After a very long hunting-gathering period, the first agricultural civilizations were born at the end of the last ice age. Agricultural practices generated a surplus of food, which was a prerequisite for the birth of modern societies. During the twentieth century, the modern agriculture was developed and now yields more food than ever before: less than 20% of our global population works to provide the whole mankind with food.
As environmental problems and resource constraints are arising, we now turn to agriculture in the hope for solutions regarding future sustainability. Could agriculture provide us with both food and fuel? Could we contribute to climate change mitigation by letting plants exploit the carbon dioxide that has been accumulated in the atmosphere? There are many promises, and we know that plants are our ultimate companions in life. However, more systemic methods are required to cope with multi-functionality and living systems so that we do not end up causing new problems as we try to cope with those already there.
This EPJ Plus Focus Point addresses the present and historical development of agriculture, perspectives of plant exploitation for food and energy production in a logic of social, economic and environmental sustainability. The articles are freely accessible until 20 April. For further information read the Editorial
EPJ Plus Focus Point - Rewriting Nuclear Physics textbooks: 30 years with radioactive ion beam physics
- Published on Monday, 27 February 2017 16:59
Guest editors: N. Alamanos, C. Bertulani, A. Bracco, A. Bonaccorso, D. Brink and G. Casini
This collection of articles contains the lectures given at the Summer School "Re-writing Nuclear Physics textbooks: 30 years of radioactive ion beam physics`` which was held at the INFN Sezione di Pisa and Department of Physics of the University of Pisa during the week 20-24 July 2015.
The school celebrated thirty years since the publication of the first papers (I. Tanihata et al., Phys. Rev. Lett. 55, (1985) 2676 and P.G. Hansen, B. Jonson, Europhys. Lett. 4, (1987) 409) in which radioactive ion beams (RIBs) were used to study properties of atomic nuclei. The school consisted of twelve lectures published here and freely accessible until 24 April 2017. Each lecture covers a topic contained in a standard Nuclear Physics textbook extended to show how our understanding has deeply changed due to the experience accumulated with RIB physic. The collection is directed mainly to third and fourth year undergraduate students but it could be seen also as an update for teachers of basic Nuclear Physics courses.
For further information read the Editorial here.
EPJ H Highlight - Historical account of how donut-shaped fusion plasmas managed to decrease adverse turbulence
- Published on Monday, 20 February 2017 16:35
Achieving fusion has become more realistic since plasma flow was identified as regulating turbulence in the 1980s
Fusion research has been dominated by the search for a suitable way of ensuring confinement as part of the research into using fusion to generate energy. In a recent paper published in EPJ H, Fritz Wagner from the Max Planck Institute for Plasma Physics in Germany, gives a historical perspective outlining how our gradual understanding of improved confinement regimes for what are referred to as toroidal fusion plasmas –- confined in a donut shape using strong magnetic fields-- have developed since the 1980s. He explains the extent to which physicists’ understanding of the mechanisms governing turbulent transport in such high-temperature plasmas has been critical in improving the advances towards harvesting fusion energy.
- Published on Monday, 20 February 2017 16:17
New study reveals characteristic of islands of magnetic metals between vacuum gaps, displaying tunnelling electric current
The nanometric-size islands of magnetic metal sporadically spread between vacuum gaps display unique conductive properties under a magnetic field. In a recent study published in EPJ Plus, Anatoliy Chornous from Sumy State University in Ukraine and colleagues found that the vacuum gaps impede the direct magnetic alignment between the adjacent islands - which depends on the external magnetic field - while allowing electron tunneling between them. Such externally controlled conducting behaviour opens the door for applications in electronics with magnetic field sensors - which are used to read data on hard disk drives - biosensors and microelectromechanical systems (MEMS), as well as in spintronics with magnetic devices used to increase memory density.
- Published on Wednesday, 08 February 2017 18:07
The first international nano-car race will be held in Toulouse, France, during spring 2017, with the participation of six international teams. The training session of the Dresden Team is reported here.
To prepare their participation, Eisenhut et al. exercised on the Toulouse LT-UHV 4-STM reconfigured for the race with 4 independent controllers (one per scanning tunneling microscope (STM)). Their findings are reported in EPJ AP.