Analysis of dynamic stall using unsteady boundary-layer theory

The unsteady turbulent boundary layer and potential flow about a pitching airfoil are analyzed using numerical methods to determine the effect of pitch rate on the delay in forward movement of the rear flow reversal point. An explicit finite difference scheme is used to integrate the unsteady boundary layer equations, which are coupled at each instant of time to a fully unsteady and nonlinear potential flow analysis. A substantial delay in forward movement of the reversal point is demonstrated with increasing pitch rate, and it is shown that the delay results partly from the alleviation of the gradients in the potential flow, and partly from the effects of unsteadiness in the boundary layer itself. The predicted delay in flow-reversal onset, and its variation with pitch rate, are shown to be in reasonable agreement with experimental data relating to the delay in dynamic stall. From the comparisons it can be concluded (a) that the effects of time-dependence are sufficient to explain the failure of the boundary layer to separate during the dynamic overshoot, and (b) that there may be some link between forward movement of the reversal point and dynamic stall

Studies of vertical wind profiles at Cape Kennedy, Florida Final report

Vertical wind profiles spectral analysis and numerical wind forecasts at Cape Kenned

A statistical model for the intrinsically broad superconducting to normal transition in quasi-two-dimensional crystalline organic metals

Although quasi-two-dimensional organic superconductors such as $\kappa$-(BEDT-TTF)$_2$Cu(NCS)$_2$ seem to be very clean systems, with apparent quasiparticle mean-free paths of several thousand \AA, the superconducting transition is intrinsically broad (e.g $\sim 1$ K wide for $T_c \approx 10$ K). We propose that this is due to the extreme anisotropy of these materials, which greatly exacerbates the statistical effects of spatial variations in the potential experienced by the quasiparticles. Using a statistical model, we are able to account for the experimental observations. A parameter $\bar{x}$, which characterises the spatial potential variations, may be derived from Shubnikov-de Haas oscillation experiments. Using this value, we are able to predict a transition width which is in good agreement with that observed in MHz penetration-depth measurements on the same sample.Comment: 8 pages, 2 figures, submitted to J. Phys. Condens. Matte

Collaborative Mapping of London Using Google Maps: The LondonProfiler

This paper begins by reviewing the ways in which the innovation of Google Maps has transformed our ability to reference and view geographically referenced data. We describe the ways in which the GMap Creator tool developed under the ESRC National Centre for E Social Science programme enables users to ‘mashup’ thematic choropleth maps using the Google API. We illustrate the application of GMap Creator using the example of www.londonprofiler.org, which makes it possible to view a range of health, education and other socioeconomic datasets against a backcloth of Google Maps data. Our conclusions address the ways in which Google Map mashups developed using GMap Creator facilitate online exploratory cartographic visualisation in a range of areas of policy concern

Phantom energy from graded algebras

We construct a model of phantom energy using the graded Lie algebra SU(2/1). The negative kinetic energy of the phantom field emerges naturally from the graded Lie algebra, resulting in an equation of state with w<-1. The model also contains ordinary scalar fields and anti-commuting (Grassmann) vector fields which can be taken as two component dark matter. A potential term is generated for both the phantom fields and the ordinary scalar fields via a postulated condensate of the Grassmann vector fields. Since the phantom energy and dark matter arise from the same Lagrangian the phantom energy and dark matter of this model are coupled via the Grassman vector fields. In the model presented here phantom energy and dark matter come from a gauge principle rather than being introduced in an ad hoc manner.Comment: 8 pages no figures; references added and discussion on condensate of vector grassman fields added. To be published MPL

Prevalence of Common Mental Disorders in a Rural District of Kenya, and Socio-Demographic Risk Factors

Association between common mental disorders (CMDs), equity, poverty and socio-economic functioning are relatively well explored in high income countries, but there have been fewer studies in low and middle income countries, despite the considerable burden posed by mental disorders, especially in Africa, and their potential impact on development. This paper reports a population-based epidemiological survey of a rural area in Kenya. A random sample of 2% of all adults living in private households in Maseno, Kisumu District of Nyanza Province, Kenya (50,000 population), were studied. The Clinical Interview Schedule-Revised (CIS-R) was used to determine the prevalence of common mental disorders (CMDs). Associations with socio-demographic and economic characteristics were explored. A CMD prevalence of 10.8% was found, with no gender difference. Higher rates of illness were found in those who were of older age and those in poor physical health. We conclude that CMDs are common in Kenya and rates are elevated among people who are older, and those in poor health

Experimental observation of Frohlich superconductivity in high magnetic fields

Resistivity and irreversible magnetisation data taken within the high-magnetic-field CDWx phase of the quasi-two-dimensional organic metal alpha-(BEDT-TTF)2KHg(SCN)4 are shown to be consistent with a field-induced inhomogeneous superconducting phase. In-plane skin-depth measurements show that the resistive transition on entering the CDWx phase is both isotropic and representative of the bulk.Comment: ten pages, four figure

Crisis management during anaesthesia: vascular access problems

© 2005 BMJ Publishing Group Ltd.Background: In confronting an evolving crisis, the anaesthetist should consider the vascular catheter as a potential cause, abandoning assumptions that the device has been satisfactorily placed and is functioning correctly. Objectives: To examine the role of a previously described core algorithm "COVER ABCD–A SWIFT CHECK", supplemented by a specific sub-algorithm for vascular access problems, in the management of crises occurring in association with anaesthesia. Methods: The potential performance of a structured approach was evaluated for each of the relevant incidents among the first 4000 reported to the Australian Incident Monitoring Study (AIMS). Results: There were 128 incidents involving problems related to vascular access. The structured approach begins distally, checking the infusion device or fluid (12 incidents), moving proximally by way of the fluid giving line (10), the line deadspace (8), then the catheter/skin interface (65), and on to the peripheral vascular tree (3) and central venous space (23), and finally, the interface of the vascular access system and the attending staff (7). The approach was able to accommodate all the vascular access problems among the first 4000 incidents reported to AIMS. Conclusion: The approach has potential as an easily remembered and applied clinical tool to lead to early resolution of vascular access problems occurring during anaesthesia

Crisis management during anaesthesia: water intoxication

© 2005 BMJ Publishing Group Ltd.Background: Irrigation of closed body spaces may lead to substantial perioperative fluid and electrolyte shifts. A syndrome occurring during transurethral resection of prostate (TURP), and a similar syndrome described in women undergoing transcervical endometrial ablation (TCEA) are both characterised by a spectrum of symptoms which may range from asymptomatic hyponatraemia to convulsions, coma, and death. Such potentially serious consequences require prompt recognition and appropriate management of this "water intoxication" syndrome. Objectives: To examine the role of a previously described core algorithm "COVER ABCD–A SWIFT CHECK", supplemented by a specific sub-algorithm for water intoxication, in the management of this syndrome occurring in association with anaesthesia. Methods: The potential performance of this structured approach for each of the relevant incidents among the first 4000 reported to the Australian Incident Monitoring Study (AIMS) was compared with the actual management as reported by the anaesthetists involved. Results: From the first 4000 incidents reported to AIMS, 10 reports of water intoxication were identified, two from endometrial ablations under general anaesthesia and eight from male urological procedures under spinal anaesthesia. The "core" crisis management algorithm detected a problem in seven cases; however, it was deficient in dealing with neurological presentations. Diagnosis of the cause of the incident would have required a specific water intoxication sub-algorithm in eight cases and a hypotension algorithm in a further two cases. Corrective strategies also required a specific sub-algorithm in eight cases, while the hypotension and cardiac arrest sub-algorithms were required in conjunction with the water intoxication sub-algorithm in the remaining two.M T Kluger, S M Szekely, R J Singleton, S C Help

Comparison of the Fermi-surface topologies of kappa-(BEDT-TTF)_2 Cu(NCS)_2 and its deuterated analogue

We have measured details of the quasi one-dimensional Fermi-surface sections in the organic superconductor kappa-(BEDT-TTF)_2 Cu(NCS)_2 and its deuterated analogue using angle-dependent millimetre-wave techniques. There are significant differences in the corrugations of the Fermi surfaces in the deuterated and undeuterated salts. We suggest that this is important in understanding the inverse isotope effect, where the superconducting transition temperature rises on deuteration. The data support models for superconductivity which invoke electron-electron interactions depending on the topological properties of the Fermi surface