Modelling the vibration of tyre sidewalls

This is the author's accepted manuscript of the article published in the Journal of Sound and Vibration - available at http://www.elsevier.co

Discussion of ‘On the theory of standing waves in tyres at high vehicle speeds’ by V.V. Krylov and O. Gilbert, Journal of Sound and Vibration 329 (2010) 4398-4408

This is the author's accepted manuscript of the article published in the Journal of Sound and Vibration - available at http://www.elsevier.co

Comment on "A theory of three-dimensional parachute dynamic stability"

The subject of this comment is a pioneering early study of parachute stability [1]. Although published almost 50 years ago, it continues to be cited by current researchers in the field. Its nonlinear time-domain simulations may have been superseded by more recent computations, but the insight provided by its linearized formulation remains valuable. Unfortunately, the paper as published contains some inconsistencies in the formulas describing the “longitudinal” (symmetric) motions of the gliding parachute. This comment aims to establish whether these are simply typographical errors or mistakes that affect the reliability of the results. It is intended to be read in conjunction with the original publicationThis is the author accepted manuscript. The final version is available from the American Institute of Aeronautics and Astronautics via https://doi.org/10.2514/1.C03366

The potential of future aircraft technology for noise and pollutant emissions reduction

The negative external impacts of aviation are currently under unprecedented scrutiny. In response, a number of studies into future prospects for improvement have recently been carried out. This paper reviews these studies and discusses their combined implications for emissions of carbon dioxide, oxides of nitrogen, and noise. The results are also compared with targets for emissions reduction proposed by ACARE and NASA. It is concluded that significant future gains are achievable, but not to the extent implied by the ACARE and NASA targets, which represent an unrealistically optimistic view of technological potential over the next 20–40 years. The focus on technological advance also deflects attention from the substantial benefits available from combining present-day technology with behavioural change. Finally, difficult policy decisions will be necessary; the greatest benefits are associated with technological developments that will require major, and long-term, investment for their realisation, and there will be increasing conflict between environmental and noise goals.This is the accepted version of the article. The final version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S0967070X14000481

Restrictive covenants in Xanadu

Legal scholarship is naturally inclined towards explanations and justifications of contemporary law. In the case of restrictive covenants and building schemes this has led to a distorted perception of the historical record, as revealed in recorded case reports dating from the nineteenth century. It is argued that the restrictive covenant had its historical genesis not in a response to industrialisation and mass urbanisation, but in the developments of resort towns in the eighteenth and early nineteenth centuries, as a response to the needs of land developers. Furthermore, it is argued that a better historical understanding of these origins illuminates contemporary problems concerned with the adaptability of law and the potential roles of law in development

Decomposition of the forces on a body moving in an incompressible fluid

The identification of separate physical features contributing to the force resultants on a moving body is useful for insight into the associated flow, and for conceptual modelling. A natural approach is to seek a component due to viscosity and an `inviscid' remainder. It is also attractive to invoke the well-known decomposition of the velocity field into irrotational and rotational parts, and apportion the force resultants accordingly. Unfortunately, this leads to coupled contributions; the resultants nominally associated with the rotational velocities depend also on the irrotational velocity field. Here, an alternative is presented, in which the inviscid resultants are split into independent `convective' and 'accelerative' components. The former are associated with the pressure field that would arise in an inviscid flow with (instantaneously) the same velocities as the real one, and with the body's velocity parameters --- angular and translational --- unchanging. The latter correspond to the pressure generated when the body accelerates from rest in quiescent fluid with its given rates of change of angular and translational velocity. They are reminiscent of the classical, `added-mass', force resultants associated with irrotational flow, but differ crucially in applying without restriction. They are also simpler than the developed expressions for the added-mass force and moment. Finally, the force resultants due to viscosity also include a contribution from pressure. Its presence is necessary because the convective and accelerative components alone are insufficient to satisfy the equations governing the pressure field, but its existence does not seem to have been widely recognised

Interpolation for de-Dopplerisation

'De-Dopplerisation' is one aspect of a problem frequently encountered in experimental acoustics: deducing an emitted source signal from received data. It is necessary when source and receiver are in relative motion, and requires interpolation of the measured signal. This introduces error. In acoustics, typical current practice is to employ linear interpolation and reduce error by over-sampling. In other applications, more advanced approaches with better performance have been developed. Associated with this work is a large body of theoretical analysis, much of which is highly specialised. Nonetheless, a simple and compact performance metric is available: the Fourier transform of the `kernel' function underlying the interpolation method. Furthermore, in the acoustics context, it is a more appropriate indicator than other, more abstract, candidates. On this basis, interpolators from three families previously identified as promising --- piecewise-polynomial, windowed-sinc, and B-spline-based --- are compared. The results show that significant improvements over linear interpolation can straightforwardly be obtained. The recommended approach is B-spline-based interpolation, which performs best irrespective of accuracy specification. Its only drawback is a pre-filtering requirement, which represents an additional implementation cost compared to other methods. If this cost is unacceptable, and aliasing errors (on re-sampling) up to approximately 1% can be tolerated, a family of piecewise-cubic interpolators provides the best alternative

Foot health education for people with rheumatoid arthritis : the practitioner's perspective

Background: Patient education is considered to be a key role for podiatrists in the management of patients with rheumatoid arthritis (RA). Patient education has undoubtedly led to improved clinical outcomes, however no attempts have been made to optimise its content or delivery to maximise benefits within the context of the foot affected by rheumatoid arthritis. The aim of this study was to identify the nature and content of podiatrists' foot health education for people with RA. Any potential barriers to its provision were also explored. Methods: A focus group was conducted. The audio dialogue was recorded digitally, transcribed verbatim and analysed using a structured, thematic approach. The full transcription was verified by the focus group as an accurate account of what was said. The thematic analysis framework was verified by members of the research team to ensure validity of the data. Results: Twelve members (all female) of the north west Podiatry Clinical Effectiveness Group for Rheumatology participated. Six overarching themes emerged: (i) the essence of patient education; (ii) the content; (iii) patient-centred approach to content and timing; (iv) barriers to provision; (v) the therapeutic relationship; and (vi) tools of the trade. Conclusion: The study identified aspects of patient education that this group of podiatrists consider most important in relation to its: content, timing, delivery and barriers to its provision. General disease and foot health information in relation to RA together with a potential prognosis for foot health, the role of the podiatrist in management of foot health, and appropriate self-management strategies were considered to be key aspects of content, delivered according to the needs of the individual. Barriers to foot health education provision, including financial constraints and difficulties in establishing effective therapeutic relationships, were viewed as factors that strongly influenced foot health education provision. These data will contribute to the development of a patient-centred, negotiated approach to the provision of foot health education for people with RA

Investigation of unsteady surface pressures over a two-wheeled landing-gear model

© 2016 by A. Gatto. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.Unsteady flow around deployed landing gears is a significant contributor to aircraft noise on approach. The farfield sound is largely determined by the fluctuating pressures on the gear surface, quantities that have yet to be fully characterized even for simplified representations. The current work reports axle- and wheel-surface data from a comprehensive set of measurements on a generic, two-wheel, landing-gear model. The results show the expected high levels of unsteadiness on areas exposed to large-scale separated flow, of which some (wheel rear surfaces and forward edges) can be identified from steady data, but others (wheel faces adjacent to axle wakes, flow impingements on sidewalls) cannot. The forward-edge values for the current, untripped configuration are markedly greater than previously reported measurements with artificial transition fixing. Spectral analysis highlights a further category of potentially important contributions that are not easily detected in overall rms values: high-frequency unsteadiness associated with turbulent attached, or attaching, flows. A key implication of these results is the need for accurate representation of the true, full-scale, boundary-layer state in computations and model-scale testing. Copyrigh

Fluoromycobacteriophages for rapid, specific, and sensitive antibiotic susceptibility testing of Mycobacterium tuberculosis

Rapid antibiotic susceptibility testing of Mycobacterium tuberculosis is of paramount importance as multiple- and extensively- drug resistant strains of M. tuberculosis emerge and spread. We describe here a virus-based assay in which fluoromycobacteriophages are used to deliver a GFP or ZsYellow fluorescent marker gene to M. tuberculosis, which can then be monitored by fluorescent detection approaches including fluorescent microscopy and flow cytometry. Pre-clinical evaluations show that addition of either Rifampicin or Streptomycin at the time of phage addition obliterates fluorescence in susceptible cells but not in isogenic resistant bacteria enabling drug sensitivity determination in less than 24 hours. Detection requires no substrate addition, fewer than 100 cells can be identified, and resistant bacteria can be detected within mixed populations. Fluorescence withstands fixation by paraformaldehyde providing enhanced biosafety for testing MDR-TB and XDR-TB infections. © 2009 Piuri et al