Road damage due to dynamic tyre forces measured on a public road

This paper describes a series of tests conducted on a UK trunk road, in which the dynamic tyre forces generated by over 1500 heavy goods vehicles (HGVs) were measured using a load measuring mat containing 144 capacitive strip sensors. The data was used to investigate the relative road damaging potential of the various classes of vehicles, and the degree of spatial repeatability of tyre forces present in a typical highway fleet. Approximately half the vehicles tested were found to contribute to a spatially repeatable pattern of pavement loading. On average, air suspended vehicles were found to generate lower dynamic load coefficients than steel suspended vehicles. However, air suspended vehicles also generated higher mean levels of theoretical road damage (aggregate force) than steel suspended vehicles, indicating that the ranking of suspensions depends on the pavement damage criterion used.

Pulsed field magnetization of a high temperature superconducting motor

As we known, the high temperature (77 K) superconducting (HTS) motor is considered as a competitive electrical machine by more and more people. There have been various of designs for HTS motor in the world. However, most of them focus on HTS tapes rather than bulks. Therefore, in order to investigate possibility of HTS bulks on motor application, a HTS magnet synchronous motor which has 75 pieces of YBCO bulks surface mounted on the rotor has been designed and developed in Cambridge University. After pulsed field magnetization (PFM) process, the rotor can trap a 4 poles magnetic field of 375 mT. The magnetized rotor can provide a maximum torque of 49.5 Nm and a maximum power of 7.8 kW at 1500 rpm. © 2010 IEEE.

A novel design of Thermally Actuated Magnetization Flux pump for high temperature superconducting bulks

High temperature superconductors, such as melt-processed YBCO bulks, have great advantages on trapping strong magnetic fields in liquid nitrogen. To enable them to function well, there are some traditional ways of magnetizing them, in which the YBCO bulks are magnetized instantly under a very strong source of magnetic field. These ways would consume great amounts of power to make the superconductors trap as much field as possible. Thermally Actuated Magnetization (TAM) Flux pump has been proved a perfect substitution for these expensive methods by using a relatively small magnet as the source. In this way, the field is developed gradually over many pulses. Unlike conventional flux pumping ways, the TAM does not drive the superconductor normal during the process of magnetization. In former experiments for the flux pump, some fundamental tests were done. In this paper, the experiment system is advanced to a new level with better temperature control to the thermal waves moving in the Gadolinium and with less air gap for the flux lines sweeping through the superconductor. This experiment system F leads to a stronger accumulation of the magnetic field trapped in the YBCO bulk. We also tried different ways of sending the thermal waves and found out that the pumping effect is closely related to the power of the heaters and the on and off time. © 2010 IEEE.

Breathers and thermal relaxation as a temporal process: A possible way to detect breathers in experimental situations

Breather stability and longevity in thermally relaxing nonlinear arrays is investigated under the scrutiny of the analysis and tools employed for time series and state reconstruction of a dynamical system. We briefly review the methods used in the analysis and characterize a breather in terms of the results obtained with such methods. Our present work focuses on spontaneously appearing breathers in thermal Fermi-Pasta-Ulam arrays but we believe that the conclusions are general enough to describe many other related situations; the particular case described in detail is presented as another example of systems where three incommensurable frequencies dominate their chaotic dynamics (reminiscent of the Ruelle-Takens scenario for the appearance of chaotic behavior in nonlinear systems). This characterization may also be of great help for the discovery of breathers in experimental situations where the temporal evolution of a local variable (like the site energy) is the only available/measured data. © 2005 American Institute of Physics.

Distribution matching for transduction

Many transductive inference algorithms assume that distributions over training and test estimates should be related, e.g. by providing a large margin of separation on both sets. We use this idea to design a transduction algorithm which can be used without modification for classification, regression, and structured estimation. At its heart we exploit the fact that for a good learner the distributions over the outputs on training and test sets should match. This is a classical two-sample problem which can be solved efficiently in its most general form by using distance measures in Hilbert Space. It turns out that a number of existing heuristics can be viewed as special cases of our approach.

Modelling and characterisation of an ortho-planar micro-valve

The main difficulties encountered in the development of microscale fluidic pumping systems stem from the fact that these systems tend to comprise highly three-dimensional parts, which are incompatible with traditional microproduction technologies. Regardless of the type of pumping principle, most of the hydraulic systems contain valves and in particular a one-way valve. This paper presents the design and modelling of an ortho-planar one-way microvalve. The main advantages of such a valve are that it is very compact and can be made from a single flat piece of material. An analytical model of the spring deflection has been developed and compared to FEM. A prototype with a bore of 1.5 mm has been build using a micro EDM (electro discharge machining) machine and also tested. © 2006 International Federation for Information Processing.

Clustering behaviors in networks of integrate-and-fire oscillators

Clustering behavior is studied in a model of integrate-and-fire oscillators with excitatory pulse coupling. When considering a population of identical oscillators, the main result is a proof of global convergence to a phase-locked clustered behavior. The robustness of this clustering behavior is then investigated in a population of nonidentical oscillators by studying the transition from total clustering to the absence of clustering as the group coherence decreases. A robust intermediate situation of partial clustering, characterized by few oscillators traveling among nearly phase-locked clusters, is of particular interest. The analysis complements earlier studies of synchronization in a closely related model. © 2008 American Institute of Physics.

A survey of alternative once-through fast reactor core designs

Reprocessing of Light Water Reactor (LWR) spent fuel to recover plutonium or transuranics for use in Sodium cooled Fast Reactors (SFRs) is a distant prospect in the U.S.A. This has motivated our evaluation of potentially cost-effective operation of uranium startup fast reactors (USFRs) in a once-through mode. This review goes beyond findings reported earlier based on a UC fueled MgO reflected SFR to describe a broader parametric study of options. Cores were evaluated for a variety of fuel/coolant/reflector combinations: UC/UZr/UO 2/UN;Na/Pb; MgO/SS/Zr. The challenge is achieving high burnup while minimizing enrichment and respecting both cladding fluence/dpa and reactivity lifetime limits. These parametric studies show that while UC fuel is still the leading contender, UO 2 fuel and ZrH 1.7 moderated metallic fuel are also attractive if UC proves to be otherwise inadequate. Overall, these findings support the conclusion that a competitive fuel cycle cost and uranium utilization compared to LWRs is possible for SFRs operated on a once-through uranium fueled fuel cycle. In addition, eventual transition to TRU recycle mode is studied, as is a small test reactor to demonstrate key features.