A variety of Levitrons : a review

After a brief history and critique of some older instruments, several new Levitron geometries are described. As a result of their greater stability these devices can be used as analogues of a number of phenomena and applications, including magnetic resonance techniques, atom traps and accelerator rings. In particular, the notion of the spinning magnet (or spignet) in a linear trap is similar to the mechanism underpinning the confinement of antihydrogen in a magnetic minimum trap, as achieved in experiments at CERN

Energy coupling in short pulse laser solid interactions and its impact for space debris removal

Significant advances have been made over the last decade to improve the performance, efficiency, and contrast of high peak and average power laser systems, driven by their use in a wide variety of fields, from the industrial to the scientific. As the contrast of the lasers has improved, interactions with contrasts of 1012 are now routinely undertaken. At such high contrasts, there is negligible preplasma formation and the ionized surface layer created by subpicosecond-duration pulses typically forms a highly reflective "plasma mirror" capable of reflecting between 70% and 90% of the incident energy. Although such interactions are of significant interest for applications such as harmonic source production and to enable the underlying physics to be studied, their low absorption can limit their usefulness for applications such as space debris removal

Teaching children basic life support skills

Can improve outcomes but implementation needs to be earlier and more widesprea

Padma Kant Shukla July 7, 1950 - January 26, 2013

Professor Padma Kant Shukla passed away suddenly on 26 January 2013 during his travel to New Delhi, India, the day after receiving the prestigious Hind Rattan (Jewel of India) Award. He was born 7 July 1950 in the village Tulapur, Uttar Pradesh (UP), India and was educated there. He graduated with Ph.D. in Physics from Banaras Hindu University in Varanasi, India at age 22. In 1975, he obtained his second doctorate degree in Theoretical Plasma Physics from Umea University under the supervision of one of us (L.S.). Affiliated with 14 academic and national institutions around the world throughout his career, his primary affiliation for 40 years was the Faculty of Physics & Astronomy, Ruhr-University Bochum (RUB), Germany, where in July 2010 he was appointed RUB International Chair, a lifetime Distinguished Physics Professor position. Padma Shukla published about 1500 papers in prestigious journals, playing very often a leading role in the exploration of new frontiers of plasma science, with special emphasis on the physics of dusty plasmas, on neutrino plasma physics, on nonlinear wave phenomena including parametric instabilities, on solitons and vortices, and on dense quantum plasma modes and structures. He was passionate about science and had an infectious enthusiasm that touched everyone who knew him

Best Practice Guideline: Transportation of People Seated in Wheelchairs, Version 2.21.

Summary, key points: Transport considerations ought to be factored into the initial phase of the wheelchair & seating assessment process. Manufacturers of wheelchairs and seating systems should make information relating to the safe transportation of their products readily available - and easy to understand. With the desire to provide the safest possible transport environment for wheelchair-seated passengers, and other vehicle occupants, all stakeholders must engage in a multi-disciplinary approach to ensuring transport safety; involving the wheelchair user with their families, carers, equipment prescribers, and transport providers*. A proven crashworthy wheelchair, used in conjunction with a proven wheelchair tie-down and occupant restraint system (WTORS), is fundamental to the provision of safe transport for both people who remain seated in their wheelchairs in a motor vehicle and other vehicle occupants. Exceptions exist on certain high-mass, low-speed urban public transport vehicles, where the likelihood of a crash situation and the severity thereof are low. Powered and manual wheelchairs offer a large variety of seated postures through their tilt, recline, and other mechanisms. Guidelines ought to be given by manufacturers with respect to use of these mechanisms during transport. The combination of a crashworthy seating system, that accommodates the proper fit of the occupant restraints, and a crashworthy wheelchair serve to indicate to the prescriber that the risks of equipment failure when exposed to crash conditions during transport have been reduced as far as reasonably possible. To minimise injury risk for wheelchair occupants, prescribers shall seek to ensure that the means of attachment of the seating system to the wheelchair is suitable for use in transport. It is imperative that the manufacturer’s instructions for use and fitting instructions for seating systems are carefully adhered to. Due to the individual nature of disability, prescribers may at times be faced with the need to work beyond manufacturers’ recommendations for the use of systems in order to maximise medical benefits, and to address the postural and functional needs of a wheelchair user. In such cases a risk management process ought to be followed, and transport providers should have a working comprehension of the relevant documented risk assessment process and understand the subsequent Risk/Benefit analysis. When properly used, a WTORS allows the wheelchair to be well secured to the vehicle floor and the passenger in the wheelchair to benefit from a properly fitted seatbelt system. Wheelchair manufacturers should highlight in their pre-sale literature any special requirements relating to the use of their wheelchair with WTORS. This information should include the configuration of the representative wheelchair, which was subjected to crash testing, so that informed decisions can be made with respect to wheelchair selection & configuration. Prescriber awareness of the type of transport environment and the facilities available to assist vehicle entry and egress is highly beneficial in the risk analysis process

Deep RL at Scale: Sorting Waste in Office Buildings with a Fleet of Mobile Manipulators

We describe a system for deep reinforcement learning of robotic manipulation skills applied to a large-scale real-world task: sorting recyclables and trash in office buildings. Real-world deployment of deep RL policies requires not only effective training algorithms, but the ability to bootstrap real-world training and enable broad generalization. To this end, our system combines scalable deep RL from real-world data with bootstrapping from training in simulation, and incorporates auxiliary inputs from existing computer vision systems as a way to boost generalization to novel objects, while retaining the benefits of end-to-end training. We analyze the tradeoffs of different design decisions in our system, and present a large-scale empirical validation that includes training on real-world data gathered over the course of 24 months of experimentation, across a fleet of 23 robots in three office buildings, with a total training set of 9527 hours of robotic experience. Our final validation also consists of 4800 evaluation trials across 240 waste station configurations, in order to evaluate in detail the impact of the design decisions in our system, the scaling effects of including more real-world data, and the performance of the method on novel objects. The projects website and videos can be found at \href{http://rl-at-scale.github.io}{rl-at-scale.github.io}.Comment: Published at Robotics: Science and Systems 202