Numerical investigation of the effects of pedestrian barriers on aeroelastic stability of a proposed footbridge

A numerical investigation into the aerodynamic characteristics and aeroelastic stability of a proposed footbridge across a motorway in the north of England has been undertaken. The longer than usual span, along with the unusual nature of the pedestrian barriers, indicated that the deck configuration was likely to be beyond the reliable limits of the British design code BD 49/01. In particular, the investigation focussed on the susceptibility of the bridge due to flutter, and to assess if the design wind speeds could be met satisfactorily. The calculations were performed using the discrete vortex method, DIVEX, developed at the Universities of Glasgow and Strathclyde. DIVEX has been successfully validated on a wide range of problems, including the aeroelastic response of bridge deck sections. The proposed deck configuration, which incorporated a pedestrian barrier comprised of angled flat plates, was found to be unstable at low wind speeds with the plates having a strong turning effect on the flow at the leading edge of the deck. DIVEX was used to assess a number of alternative design options, investigating the stability with respect to flutter for each configuration. Reducing the number of flat plates and their angle to the deck lessened the effect of the barrier on the overall aerodynamic characteristics and increased the stability of the bridge to an acceptable level, with the critical flutter speed in excess of the specified design speed

Studies of new perfluoroether elastomeric sealants

Channel and filleting sealants were developed successfully from cyano and diamidoxime terminated perfluoro alkylene ether prepolymers. The prepolymers were polymerized, formulated and tested. The polymers and/or formulations therefrom were evaluated as to their physical, mechanical and chemical properties (i.e., specific gravity, hardness, nonvolatile content, corrosion resistance, stress corrosion, pressure rupture resistance, low temperature flexibility, gap sealing efficiency, tensile strength and elongation, dynamic mechanical behavior, compression set, fuel resistance, thermal properties and processability). Other applications of the formulated polymrs and incorporation of the basic prepolymers into other polymeric systems were investigated. A cyano terminated perfluoro alkylene oxide triazine was formulated and partially evaluated. The channel sealant in its present formulation has excellent pressure rupture resistance and surpasses present MIL specifications before and after fuel and heat aging

High performance channel injection sealant invention abstract

High performance channel sealant is based on NASA patented cyano and diamidoximine-terminated perfluoroalkylene ether prepolymers that are thermally condensed and cross linked. The sealant contains asbestos and, in its preferred embodiments, Lithofrax, to lower its thermal expansion coefficient and a phenolic metal deactivator. Extensive evaluation shows the sealant is extremely resistant to thermal degradation with an onset point of 280 C. The materials have a volatile content of 0.18%, excellent flexibility, and adherence properties, and fuel resistance. No corrosibility to aluminum or titanium was observed

Using modern time series analysis techniques to predict ENSO events from the SOI time series

We analyze the monthly 1866–2000 Southern Oscillation Index (SOI) data to determine: whether the SOI data are sufficiently noise-free that useful predictions can be made from them, and in particular, whether future ENSO events can be predicted from the SOI data. The “Hilbert-EMD” technique is used to aid the analysis. This new frequency-time algorithm, based on the Hilbert transform, may be applied to time series for which the conventional assumptions of linearity and stationarity may not apply. With the aid of the EMD procedure, a cleaner representation of ENSO dynamics is obtained from the SOI data. A polynomial function is then used to predict SOI values. Using only the data from January 1866 through December 1996, this prediction correctly indicated a warm event in 1997–1998 and a cold event in 1999. Using all the data (through December 2000), this prediction shows no strong ENSO events (positive or negative) during the time period January 2001 through December 2004

'I'm fishing really' - inflammatory marker testing in primary care: a qualitative study

This is the final version of the article. Available from Royal College of General Practitioners via the DOI in this record.BACKGROUND: Inflammatory markers can be helpful as part of the diagnostic workup for specific diseases or for monitoring disease activity. A third use is as a screening and/or triage tool to differentiate between the presence or absence of disease. Most research into inflammatory markers looks at diagnosis of specific diseases and comes from secondary care. Qualitative studies to explore when and why clinicians use these tests in primary care are lacking. AIM: To identify clinicians' approaches to inflammatory marker testing in primary care. DESIGN AND SETTING: Qualitative study with 26 GPs and nurse practitioners. METHOD: Interviews were conducted using a semi-structured topic guide. Clinicians reviewed recent cases of inflammatory marker testing in their pathology inbox. Interviews were audiorecorded and transcribed. Qualitative analysis was conducted by two of the authors. RESULTS: Clinicians are uncertain about the appropriate use of inflammatory markers and differ in their approach to testing patients with undifferentiated symptoms. Normal or significantly elevated inflammatory markers are seen as helpful, but mildly raised inflammatory markers in the context of non-specific symptoms are difficult to interpret. Clinicians describe a tension between not wanting to 'miss anything' and, on the other hand, being wary of picking up borderline abnormalities that can lead to cascades of further tests. Diagnostic uncertainty is a common reason for inflammatory marker testing, with the aim to reassure; however, paradoxically, inconclusive results can generate a cycle of uncertainty and anxiety. CONCLUSION: Further research is needed to define when inflammatory marker testing is useful in primary care and how to interpret results.This project was funded by the RCGP Scientific Foundation Board (grant code: SFB 2014-05)

Electromagnetic Forming of AZ31B Magnesium Alloy Sheet

In the first stage of this work, polycrystalline specimens of AZ31B magnesium alloy have been characterized by uniaxial tensile tests at quasi-static and dynamic strain rates at room temperature. The influence of the strain rate is outlined and experimental results were fitted to the parameters of Johnson-Cook constitutive material model. In the second stage of the present study, sheets of AZ31B magnesium alloy have been biaxially formed by electromagnetic forming using different coil and die configurations. Deformation values measured from electromagnetic formed parts are compared to the ones achieved with uniaxial tensile tests and also with the values obtained by conventional forming technologies. Finally, numerical simulations have been carried out using an alternative method for computing the electromagnetic fields in the EMF process simulation, a combination of Finite Element Method (FEM) for conductor parts and Boundary Element Method (BEM) for the surrounding air (or more generally insulators) that is being implemented into commercial code LS-DYNA®

A trick for passing degenerate points in Ashtekar formulation

We examine one of the advantages of Ashtekar's formulation of general relativity: a tractability of degenerate points from the point of view of following the dynamics of classical spacetime. Assuming that all dynamical variables are finite, we conclude that an essential trick for such a continuous evolution is in complexifying variables. In order to restrict the complex region locally, we propose some `reality recovering' conditions on spacetime. Using a degenerate solution derived by pull-back technique, and integrating the dynamical equations numerically, we show that this idea works in an actual dynamical problem. We also discuss some features of these applications.Comment: 9 pages by RevTeX or 16 pages by LaTeX, 3 eps figures and epsf-style file are include

Gender and Species Use in Amazonian Home Gardens: the Social and Economic Context of Biodiversity Conservation

Home gardens, “the peridomestic area belonging to the household where members plant and/or tend useful plants” (Perrault-Archambault and Coomes 2008), are found throughout the world. However, their use and importance vary from region to region. In the Peruvian Amazon, owners use home gardens for a domestic supply of foods, craft materials, medicines, condiments, and shade (Miller and Nair 2006). With this wide range in function, reflected in species content, home gardens are very biodiverse. Home garden biodiversity may be increasingly important in a rapidly changing Amazonia (Betts et al. 2008). Thus, the sociocultural and economic factors contributing to home garden diversity warrant in-depth study. Existing data posit a direct positive relationship between female garden tenders and species diversity (Perrault-Archambault and Coomes 2008) as well as report a simultaneous increase in sales of indigenous plant products and monocropping (Perreault2005). Nevertheless, limited research exists on home gardens as reservoirs for species conservation (Ban and Coomes2004b). We hypothesize both the gender of the caretaker and market integration impact levels of species richness in home gardens, with female garden managers increasing biodiversity and market integration decreasing biodiversity as caretakers favor more marketable species.https://scholarship.richmond.edu/geography-posters/1005/thumbnail.jp

Assessing the implementability of telehealth interventions for self-management support: a realist review.

BACKGROUND: There is a substantial and continually growing literature on the effectiveness and implementation of discrete telehealth interventions for health condition management. However, it is difficult to predict which technologies are likely to work and be used in practice. In this context, identifying the core mechanisms associated with successful telehealth implementation is relevant to consolidating the likely elements for ensuring a priori optimal design and deployment of telehealth interventions for supporting patients with long-term conditions (LTCs). METHODS: We adopted a two-stage realist synthesis approach to identify the core mechanisms underpinning telehealth interventions. In the second stage of the review, we tested inductively and refined our understanding of the mechanisms. We reviewed qualitative papers focused on COPD, heart failure, diabetes, and behaviours and complications associated with these conditions. The review included 15 papers published 2009 to 2014. RESULTS: Three concepts were identified, which suggested how telehealth worked to engage and support health-related work. Whether or not and how a telehealth intervention enables or limits the possibility for relationships with professionals and/or peers. Telehealth has the potential to reshape and extend existing relationships, acting as a partial substitute for the role of health professionals. The second concept is fit: successful telehealth interventions are those that can be well integrated into everyday life and health care routines and the need to be easy to use, compatible with patients' existing environment, skills, and capacity, and that do not significantly disrupt patients' lives and routines. The third concept is visibility: visualisation of symptoms and feedback has the capacity to improve knowledge, motivation, and a sense of empowerment; engage network members; and reinforce positive behaviour change, prompts for action and surveillance. CONCLUSIONS: Upfront consideration should be given to the mechanisms that are most likely to ensure the successful development and implementation of telehealth interventions. These include considerations about whether and how the telehealth intervention enables or limits the possibility for relationships with professionals and peers, how it fits with existing environment and capacities to self-manage, and visibility-enabling-enhanced awareness to self and others