Series active variable geometry suspension application to comfort enhancement

This paper explores the potential of the Series Active Variable Geometry Suspension (SAVGS) for comfort and road holding enhancement. The SAVGS concept introduces significant nonlinearities associated with the rotation of the mechanical link that connects the chassis to the spring-damper unit. Although conventional linearization procedures implemented in multi-body software packages can deal with this configuration, they produce linear models of reduced applicability. To overcome this limitation, an alternative linearization approach based on energy conservation principles is proposed and successfully applied to one corner of the car, thus enabling the use of linear robust control techniques. An H∞ controller is synthesized for this simplified quarter-car linear model and tuned based on the singular value decomposition of the system's transfer matrix. The proposed control is thoroughly tested with one-corner and full-vehicle nonlinear multi-body models. In the SAVGS setup, the actuator appears in series with the passive spring-damper and therefore it would typically be categorized as a low bandwidth or slow active suspension. However, results presented in this paper for an SAVGS-retrofitted Grand Tourer show that this technology has the potential to also improve the high frequency suspension functions such as comfort and road holding

Superconductivity-Induced Anderson Localisation

We have studied the effect of a random superconducting order parameter on the localization of quasi-particles, by numerical finite size scaling of the Bogoliubov-de Gennes tight-binding Hamiltonian. Anderson localization is obtained in d=2 and a mobility edge where the states localize is observed in d=3. The critical behavior and localization exponent are universal within error bars both for real and complex random order parameter. Experimentally these results imply a suppression of the electronic contribution to thermal transport from states above the bulk energy gap.Comment: 4 pages, revtex file, 3 postscript figure

Two Interacting Electrons in a Quasiperiodic Chain

We study numerically the effect of on-site Hubbard interaction U between two electrons in the quasiperiodic Harper's equation. In the periodic chain limit by mapping the problem to that of one electron in two dimensions with a diagonal line of impurities of strength U we demonstrate a band of resonance two particle pairing states starting from E=U. In the ballistic (metallic) regime we show explicitly interaction-assisted extended pairing states and multifractal pairing states in the diffusive (critical) regime. We also obtain localized pairing states in the gaps and the created subband due to U, whose number increases when going to the localized regime, which are responsible for reducing the velocity and the diffusion coefficient in the qualitatively similar to the non-interacting case ballistic and diffusive dynamics. In the localized regime we find propagation enhancement for small U and stronger localization for larger U, as in disordered systems.Comment: 14 pages Revtex file, 8 figures (split into 19 jpg figures). (postscript versions of the jpg figures are also available upon request) submitted to PR

Evaluation of children's centres in England (ECCE) : strand 1: first survey of children's centre leaders in the most deprived areas

This report is the first output from the Evaluation of Children's Centres in England (ECCE), a six year study commissioned by the Department for Education and undertaken by NatCen Social Research, the University of Oxford and Frontier Economics. The aim of ECCE is to provide an in-depth understanding of children's centre services, including their effectiveness in relation to different management and delivery approaches and the cost of delivering different types of services. The aim of Strand 1 is to profile children’s centres in the most disadvantaged areas, providing estimates on different aspects of provision with which to select centres for subsequent stages of the evaluation and to explore different models of provision. The findings below relate to 500 children's centres that are representative of all phase 1 and 2 centres (i.e. those in the 30percent most deprived areas).</p

Oral non-Hodgkin’s lymphoma in a patient with rheumatoid arthritis treated with etanercept and methotrexate

Oral non-Hodgkin’s lymphomas (O-NHLs) are a rare group of diverse lymphoid tissue malignancies and represent less than 5% of the oral cavity malignancies and 2% of all extra-nodal NHLs. Oral-NHLs affect the Waldeyer’s- ring, the salivary glands, the bone of the jaws and the oral mucosa, their clinical appearance is very heterogeneous. Among the risk factors for NHLs are immunosuppression (primary or secondary), autoimmunity and inflammation. O-NHLs share the same risk factors. This case report describes a patient with O-NHL which was possibly linked to the combination of methotrexate and etanercept for the treatment of her rheumatoid arthritis. To our knowledge this is probably among the first cases of O-NHL with possible relation to the use of a Tumor Necrosis Factor (TNF) antagonist biological agent (etanercept). This case could contribute to the sensitization of the dentists for the signs and symptoms of this rare malignancy. It also underlines the need for thorough medical history and medication recording for all the dental patients

Localization Transition in Multilayered Disordered Systems

The Anderson delocalization-localization transition is studied in multilayered systems with randomly placed interlayer bonds of density $p$ and strength $t$. In the absence of diagonal disorder (W=0), following an appropriate perturbation expansion, we estimate the mean free paths in the main directions and verify by scaling of the conductance that the states remain extended for any finite $p$, despite the interlayer disorder. In the presence of additional diagonal disorder ($W > 0$) we obtain an Anderson transition with critical disorder $W_c$ and localization length exponent $\nu$ independently of the direction. The critical conductance distribution $P_{c}(g)$ varies, however, for the parallel and the perpendicular directions. The results are discussed in connection to disordered anisotropic materials.Comment: 10 pages, Revtex file, 8 postscript files, minor change