255 research outputs found

    PAN AIR: A computer program for predicting subsonic or supersonic linear potential flows about arbitrary configurations using a higher order panel method. Volume 3: Case manual (version 1.0)

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    Numerous applications of the PAN AIR computer program system are presented. PAN AIR is user-oriented tool for analyzing and/or designing aerodynamic configurations in subsonic or supersonic flow using a technique generally referred to as a higher order panel method. Problems solved include simple wings in subsonic and supersonic flow, a wing-body in supersonic flow, wing with deflected flap in subsonic flow, design of two-dimensional and three-dimensional wings, axisymmetric nacelle in supersonic flow, and wing-canard-tail-nacelle-fuselage combination in supersonic flow

    A higher order panel method for linearized supersonic flow

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    The basic integral equations of linearized supersonic theory for an advanced supersonic panel method are derived. Methods using only linear varying source strength over each panel or only quadratic doublet strength over each panel gave good agreement with analytic solutions over cones and zero thickness cambered wings. For three dimensional bodies and wings of general shape, combined source and doublet panels with interior boundary conditions to eliminate the internal perturbations lead to a stable method providing good agreement experiment. A panel system with all edges contiguous resulted from dividing the basic four point non-planar panel into eight triangular subpanels, and the doublet strength was made continuous at all edges by a quadratic distribution over each subpanel. Superinclined panels were developed and tested on s simple nacelle and on an airplane model having engine inlets, with excellent results

    The cost-effectiveness of an updated theory-based online health behavior intervention for new university students: U@Uni2

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    Background: The transition to university marks a point where young people may be open to changing health behaviours such as smoking, exercise, diet and alcohol intake. This study aimed to estimate the cost-effectiveness of an updated online health behaviour intervention for new university students in the UK – “U@Uni2”, compared with both a control (measurement only) scenario and with the original intervention (“U@Uni1”). Methods: The economic analysis, based on a randomised controlled trial, comprised a detailed costing analysis, a within-trial cost-effectiveness analysis and long-term economic modelling. Cost-effectiveness of the U@Uni2 trial was estimated using 6-month data on costs and health-related quality of life. An individual patient simulation model was adapted for long-term economic analysis of U@Uni2. Probabilistic sensitivity analysis and value of information analysis accounted for uncertainty in model inputs and identified key parameters. Results: The U@Uni2 intervention costs £45.97 per person for full implementation, £10.43 per person for roll-out in a different institution and £3.03 per person for roll-out over five years. The U@Uni2 trial was not cost-effective because marginally fewer quality-adjusted life years (QALYs) were obtained in the intervention arm than control. However, modelled over a lifetime, U@Uni2 is estimated to produce more QALYs than control but fewer than U@Uni1, primarily due to the effect of the interventions on smoking. Roll-out of U@Uni2 is highly likely to be more cost-effective than doing nothing (ICER = £536 per QALY, 86% probability cost-effective). Decision uncertainty occurs primarily around the effectiveness of the U@Uni2 intervention and is worth up to £3.24m. Conclusions: The U@Uni2 intervention is highly likely to be cost-effective to roll-out compared with doing nothing. The results suggest that preventing uptake of smoking is the key driver of QALY gain and should be the primary target of such interventions. Trial Registration: Current Controlled Trials ISRCTN6768418

    DFT Studies of Au(I) Catalysed Reactions : Anion Effects and Reaction Selectivity

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    Density functional theory (DFT) is a powerful tool that can aid in the exploration and development of synthetic chemistry, and its use is often applied in the chemistry of gold(I) catalysis. In this review, we discuss two different facets of these calculations – namely, the exploration and explanation of anion effects, and the regioselectivity and speciation of gold(I)-catalysed reactions. The research described herein clearly shows the importance of including the anion in DFT studies of Au(I)-catalysed reactions, especially when using low polarity solvents, or where hydrogen-bonding is prevalent. Additionally, we show that whilst using DFT to study the selectivity of reactions can be successful, benchmarking the computational results against experimental data is vitally important for ensuring that the model is accurately describing the observed results

    Practical Implementation of a General Numerical Lifting-Line Method

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    A general numerical lifting-line method provides corrections to overcome the singularities inherent in the lifting-line downwash integrals in certain cases. These singularities have previously limited the scope of lifting-line theory to straight wings not in sideslip; in all other cases, more traditional numerical approaches to solving Prandtl\u27s hypothesis fail to grid converge. However, this general numerical lifting-line method grid converges even for swept wings and wings in sideslip. In the current work, we apply the general numerical lifting-line method to any number of wings with arbitrary geometry. We also provide a dimensional derivation of the basic general numerical lifting-line equations and discuss how airfoil section properties can be corrected for sweep. We develop a linearized system of equations and a nonlinear improvement method to solve the general numerical lifting-line equations. Results show that placing the lifting-line on the wing locus of aerodynamic centers, as done by others, may not yield the most accurate results. Comparisons with published data reveal that the general numerical lifting-line method can accurately predict the lift distribution for swept wings

    Investigating Which Behaviour Change Techniques Work for Whom in Which Contexts Delivered by What Means: Proposal for an International Collaboratory of Centres for Understanding Behaviour Change (CUBiC)

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    Purpose Behaviour change techniques are fundamental to the development of any behaviour change intervention, but surprisingly little is known about their properties. Key questions include when, why, how, in which contexts, for which behaviours, in what combinations, compared with what, and for whom behaviour change techniques are typically effective. The aims of the present paper are to: (1) articulate the scope of the challenge in understanding the properties of behaviour change techniques, (2) propose means by which to tackle this problem, and (3) call scientists to action. Methods Iterative consensus (O’Connor et al., 2020, Br. J. Psychol., e12468) was used to elicit and distil the judgements of experts on how best to tackle the problem of understanding the nature and operation of behaviour change techniques. Results We propose a worldwide network of ‘Centres for Understanding Behaviour Change’ (CUBiC) simultaneously undertaking research to establish what are the single and combined properties of behaviour change techniques across multiple behaviours and populations. We additionally provide a first attempt to systematize an approach that CUBiC could use to understand behaviour change techniques and to begin to harness the efforts of researchers worldwide. Conclusion Better understanding of behaviour change techniques is vital for improving behaviour change interventions to tackle global problems such as obesity and recovery from COVID‐19. The CUBiC proposal is just one of many possible solutions to the problems that the world faces and is a call to action for scientists to work collaboratively to gain deeper understanding of the underpinnings of behaviour change interventions

    What are the environmental factors that affect implementation of the Manchester Healthy Schools programme? A qualitative exploration of staff perspectives

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    Objectives: Primary/elementary schools are crucial settings for early weight management interventions but effects on children’s weight are small. This may be because the environments in which these schools are situated support unhealthy behaviours that lead to weight gain (obesogenic environments). Staff working in schools have a unique insight into the environmental factors that might affect their efforts to support child health and weight management interventions. The aim of this study is to explore the views of staff in relation to the perceived effects of the environmental context in which they deliver a child health promotion intervention. Methods: Staff from five schools involved in delivering the Manchester Healthy Schools programme were interviewed (N=19). These interviews were transcribed verbatim and analysed thematically. Results: Three themes were produced: opportunities to be healthy; importance of funding, resources and governance; and resources available to households and neighbourhoods. Conclusion: The views of school staff were consistent with themes identified in other relevant literature. Although there were serendipitous opportunities to capitalise on local resources, such as using nearby land and leisure facilities for outdoor physical activities, many barriers relating to local environmental and resource features were reported. Joined up, multi-agency solutions such as place-based approaches might be able to offer schools some resource-based support; however, more research is needed to establish the best way to achieve the best outcomes for children

    Synthesis of macrocyclic and medium-sized ring thiolactones via the ring expansion of lactams

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    A side chain insertion method for the ring expansion of lactams into macrocyclic thiolactones is reported, that can also be incorporated into Successive Ring Expansion (SuRE) sequences. The reactions are less thermodynamically favourable than the analogous lactam- and lactone-forming ring expansion processes (with this notion supported by DFT data), but nonetheless, three complementary protecting group strategies have been developed to enable this challenging transformation to be achieved

    Multi-level fast multipole BEM for 3-D elastodynamics

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    To reduce computational complexity and memory requirement for 3-D elastodynamics using the boundary element method (BEM), a multi-level fast multipole BEM (FM-BEM) based on the diagonal form for the expansion of the elastodynamic fundamental solution is proposed and demonstrated on numerical examples involving single-region and multi-region configurations where the scattering of seismic waves by a topographical irregularity or a sediment-filled basin is examined
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