- Published on 15 August 2019
Hall thrusters, which are already used to propel spacecraft and satellites on long missions, could be used for even longer ones if models for minimising surface erosion were taken into account.
The 50th anniversary of the Apollo 11 moon landing has reignited interest in space travel. However, almost any mission beyond the moon, whether manned or unmanned, will require the spacecraft to remain fully operational for at least several years. The Hall thruster is a propulsion system that is often used by craft involved in long missions. A recent study by Andrey Shashkov and co-workers at the Moscow Institute of Physics and Technology, Russia has shown how the operating lives of these systems can be further extended; their work was recently published in EPJ D.
- Published on 05 August 2019
A new quantum-mechanical model has been developed that allows the momentum of quantum particles to be measured using a variant of the classical time-of-flight.
Quantum mechanics is an extraordinarily successful way of understanding the physical world at extremely small scales. Through it, a handful of rules can be used to explain the majority of experimentally observable phenomena. Occasionally, however, we come across a problem in classical mechanics that poses particular difficulties for translation into the quantum world. A new study published in EPJ D has provided some insights into one of them: momentum. The authors, theoretical physicists Fabio Di Pumpo and Matthias Freyberger from Ulm University, Germany, present an elegant mathematical model of quantum momentum that is accessible through another classical concept: time-of-flight.
- Published on 02 August 2019
Mathematical analysis reveals that the exponential patterns in RNA diffusion rates linked to small-scale diffusive behaviours
Recent studies have revealed that within cells of both yeast and bacteria, the rates of diffusion of RNA proteins – complex molecules that convey important information throughout the cell – are distributed in characteristic exponential patterns. As it turns out, these patterns display the highest possible degree of disorder, or ‘entropy’, of all possible diffusion processes within the cell. In new research published in EPJ B, Yuichi Itto at Aichi Institute of Technology in Japan explores this behaviour further by zooming in to study local fluctuations in the diffusion rates of RNA proteins. By associating these small-scale diffusion rates with time-varying values for entropy, he finds that the rates of change of entropy in certain time intervals are larger in areas with higher RNA diffusion rates.