Quantum Field Theory: Where We Are

We comment on the present status, the concepts and their limitations, and the successes and open problems of the various approaches to a relativistic quantum theory of elementary particles, with a hindsight to questions concerning quantum gravity and string theory.Comment: To appear in: An Assessment of Current Paradigms in the Physics of Fundamental Phenomena, to be published by Springer Verlag (2006

Design and analysis of permanent magnet electrical machines for hybrid electric vehicles

Imperial Users onl

SciTech News Volume 71, No. 3 (2017)

Columns and Reports From the Editor.........................3 Division News Science-Technology Division....5 Chemistry Division....................8 Conference Report, Marion E, Sparks Professional Development Award Recipient..9 Engineering Division................10 Engineering Division Award, Winners Reflect on their Conference Experience..15 Aerospace Section of the Engineering Division .....18 Architecture, Building Engineering, Construction, and Design Section of the Engineering Division................20 Reviews Sci-Tech Book News Reviews...22 Advertisements IEEE..........................................

Generalized harmonic modeling technique for 2D electromagnetic problems : applied to the design of a direct-drive active suspension system

The introduction of permanent magnets has significantly improved the performance and efficiency of advanced actuation systems. The demand for these systems in the industry is increasing and the specifications are becoming more challenging. Accurate and fast modeling of the electromagnetic phenomena is therefore required during the design stage to allow for multi-objective optimization of various topologies. This thesis presents a generalized technique to design and analyze 2D electromagnetic problems based on harmonic modeling. Therefore, the prior art is extended and unified to create a methodology which can be applied to almost any problem in the Cartesian, polar and axisymmetric coordinate system. This generalization allows for the automatic solving of complicated boundary value problems within a very short computation time. This method can be applied to a broad class of classical machines, however, more advanced and complex electromagnetic actuation systems can be designed or analyzed as well. The newly developed framework, based on the generalized harmonic modeling technique, is extensively demonstrated on slotted tubular permanent magnet actuators. As such, numerous tubular topologies, magnetization and winding configurations are analyzed. Additionally, force profiles, emf waveforms and synchronous inductances are accurately predicted. The results are within approximately 5 % of the non-linear finite element analysis including the slotted stator effects. A unique passive damping solution is integrated within the tubular permanent magnet actuator using eddy current damping. This is achieved by inserting conductive rings in the stator slot openings to provide a passive damping force without compromising the tubular actuator’s performance. This novel idea of integrating conductive rings is secured in a patent. A method to calculate the damping ratio due to these conductive rings is presented where the position, velocity and temperature dependencies are shown. The developed framework is applied to the design and optimization of a directdrive electromagnetic active suspension system for passenger cars. This innovative solution is an alternative for currently applied active hydraulic or pneumatic suspension systems for improvement of the comfort and handling of a vehicle. The electromagnetic system provides an improved bandwidth which is typically 20 times higher together with a power consumption which is approximately five times lower. As such, the proposed system eliminates two of the major drawbacks that prevented the widespread commercial breakthrough of active suspension systems. The direct-drive electromagnetic suspension system is composed of a coil spring in parallel with a tubular permanent magnet actuator with integrated eddy current damping. The coil spring supports the sprung mass while the tubular actuator either consumes, by applying direct-drive vertical forces, or regenerates energy. The applied tubular actuator is designed using a non-linear constrained optimization algorithm in combination with the developed analytical framework. This ensured the design with the highest force density together with low power consumption. In case of a power breakdown, the integrated eddy current damping in the slot openings of this tubular actuator, together with the passive coil spring, creates a passive suspension system to guarantee fail-safe operation. To validate the performance of the novel proof-of-concept electromagnetic suspension system, a prototype is constructed and a full-scale quarter car test setup is developed which mimics the vehicle corner of a BMW 530i. Consequently, controllers are designed for the active suspension strut for improvement of either comfort or handling. Finally, the suspension system is installed as a front suspension in a BMW 530i test vehicle. Both the extensive experimental laboratory and on-road tests prove the capability of the novel direct-drive electromagnetic active suspension system. Furthermore, it demonstrates the applicability of the developed modeling technique for design and optimization of electromagnetic actuators and devices

Artificial Photosynthesis for Solar Fuels - an Evolving Research Field within AMPEA, a Joint Programme of the European Energy Research Alliance

On the path to an energy transition away from fossil fuels to sustainable sources, the European Union is for the moment keeping pace with the objectives of the Strategic Energy Technology-Plan. For this trend to continue after 2020, scientific breakthroughs must be achieved. One main objective is to produce solar fuels from solar energy and water in direct processes to accomplish the efficient storage of solar energy in a chemical form. This is a grand scientific challenge. One important approach to achieve this goal is Artificial Photosynthesis. The European Energy Research Alliance has launched the Joint Programme "Advanced Materials & Processes for Energy Applications” (AMPEA) to foster the role of basic science in Future Emerging Technologies. European researchers in artificial photosynthesis recently met at an AMPEA organized workshop to define common research strategies and milestones for the future. Through this work artificial photosynthesis became the first energy research sub-field to be organised into what is designated "an Application” within AMPEA. The ambition is to drive and accelerate solar fuels research into a powerful European field - in a shorter time and with a broader scope than possible for individual or national initiatives. Within AMPEA the Application Artificial Photosynthesis is inclusive and intended to bring together all European scientists in relevant fields. The goal is to set up a thorough and systematic programme of directed research, which by 2020 will have advanced to a point where commercially viable artificial photosynthetic devices will be under development in partnership with industr

Eco-Education: A Required Element of Public Policies for Sustainable Social and Economic Development

In this article, the author analyzes eco-education from a transdisciplinary perspective, as part of the “new education”, referring to its current dimensions, its goals and its utility in shaping the attitudes and behaviors of contemporary humans towards their environment and towards sustainable living. The goals and content of eco-education are dependent on a new philosophy, on a new axiological and ethical orientation that is, opposed to rationalistic philosophy, which guided the age of machinism and industrialization. The new view regarding humans’ (anthroposphere) relations with nature (biosphere and geosphere), is inspired from the fundamental rights of the human being, as part of nature, from universal values which harmonize sociosphere and biosphere, the ecological awareness of contemporary society with regard to the objective laws of nature, biodiversity conservation and environmental protection by juridical laws. These goals are meant for the entire population, especially children and young people, with the aid of schools and other educational factors (church, mass – media, cultural foundations, non-governmental organizations etc.), an ecological awareness, positive feelings and attitudes with respect to the environment, skills, abilities and capacities for efficient action in the sense of protecting nature and conserving ecological circuits. The author lays an emphasis on the idea that ecological education, in all its forms, will not yield the results expected by experts and future generations if it is undertaken randomly, fragmentarily, incoherently – regardless of how diversified and quantitatively extended it might be. As a global issue of today’s society – the efficiency of eco-education is dependent on the philosophy of nature and life, materialized in a global strategy, such as that of durable and knowledge-based development, which will facilitate the harmonization of various public policies launched by contemporary organizations and authorities. Generally speaking, any public policy has an ecological component, and the obtainment of performance in ecological policies necessarily involves an adequate ecological education

Bridges Structural Health Monitoring and Deterioration Detection Synthesis of Knowledge and Technology

INE/AUTC 10.0