Iterative design for active control of fluid flow

This paper considers iterative controller design for planar Poiseuille flow by model unfalsification and controller redesign. The main contribution is to show that model-unfalsification-based iterative design can be useful in flow control problems. The a priori knowledge of the dynamics of the sampled system is obtained from the analytic approximation of the Navier-Stokes equations by a Galerkin method. Pole-positions, expected model orders and feasible dynamic variations are valuable prior knowledge which can be taken into account in the uncertainty-model unfalsification-based iterative design scheme developed

A qualitative study of Telehealth patient information leaflets (TILs) : are we giving patients enough information?

BACKGROUND: The provision of patient information leaflets regarding telehealth has been perceived by potential consumers as a strategy to promote awareness and adoption of telehealth services. However, such leaflets need to be designed carefully if adoption and awareness among potential users is to be promoted. Therefore, the aims of this study were: first, to see how telehealth was portrayed in some of the existing telehealth leaflets (THLs). Second, to explore patients' perceptions of the existing THLs and their engagement with the concept and how THLs can be optimised. METHODS: A two-step approach was employed to address the aims of this study. The first phase involved the use of discourse analysis to compare 12 electronically and publically available THLs, with the existing THL guidance "Involve Yorkshire and Humber". The second phase involved conducting 14 semi-structured interviews with potential telehealth users/patients to gauge their perception and engagement with the concept, using the two leaflets that were mostly matching with the guidance used. Six interviews were audio-recorded and eight had detailed jotted notes. The interviews were transcribed and thematically analysed to identify key themes. RESULTS: The discourse analysis showed certain gaps and variations within the screened leaflets when addressing the following aspects: cost of the telehealth service, confidentiality, patients' choices in addition to equipment use and technical support. Analysis of the interviews revealed patients' need for having clear and sufficient information about the telehealth service within the THLs; in addition to, patients' preference for the use of simpler terminologies for telehealth description and the provision of clear simple texts with pictorial presentations. The interviews also revealed certain limitations against adoption of telehealth by the participants, such as: lack of privacy and confidentiality of information, fear of technology breakdown and equipment failure, loss of face-to-face contact with healthcare professionals and being too dependent on the telehealth service. CONCLUSION: The current study showed a great variation among the screened THLs and highlighted certain gaps within the content and presentation of these leaflets. However, the study also highlighted certain key issues to be considered when designing THLs in the future to enhance telehealth uptake and use by patients

Psycho-education programme for temporomandibular disorders: a pilot study

BACKGROUND: Temporomandibular disorders (TMDs) are by far the most predominant condition affecting the temporomandibular joint (TMJ), however many patients have mild self-limiting symptoms and should not be referred for specialist care. The aim of this pilot study was to develop a simple, cost-effective management programme for TMDs using CD-ROM. 41 patients (age 18–70) participated in this study, patients were divided into three groups: the 1st group were involved in an attention placebo CD-ROM (contain anatomical information about the temporomandibular system), the 2nd group received information on CD-ROM designed to increase their control and self efficacy, while the 3rd group received the same programme of the 2nd group added to it an introduction to self-relaxing techniques followed by audio tape of progressive muscle relaxation exercises. Each of the groups was asked to complete a number of questionnaires on the day of initial consultation and six weeks afterwards. RESULTS: The two experimental groups (2nd & 3rd) were equally effective in reducing pain, disability and distress, and both were more effective than the attention placebo group (1st), however the experimental groups appeared to have improved at follow-up relative to the placebo-group in terms of disability, pain and depressed mood. CONCLUSION: This pilot study demonstrates the feasibility and acceptability of the design. A full, randomized, controlled trial is required to confirm the efficacy of the interventions developed here

The Australian Reproductive Genetic Carrier Screening Project (Mackenzie's Mission): Design and Implementation

Published: 28 October 2022Reproductive genetic carrier screening (RGCS) provides people with information about their chance of having children with autosomal recessive or X-linked genetic conditions, enabling informed reproductive decision-making. RGCS is recommended to be offered to all couples during preconception or in early pregnancy. However, cost and a lack of awareness may prevent access. To address this, the Australian Government funded Mackenzie’s Mission—the Australian Reproductive Genetic Carrier Screening Project. Mackenzie’s Mission aims to assess the acceptability and feasibility of an easily accessible RGCS program, provided free of charge to the participant. In study Phase 1, implementation needs were mapped, and key study elements were developed. In Phase 2, RGCS is being offered by healthcare providers educated by the study team. Reproductive couples who provide consent are screened for over 1200 genes associated with >750 serious, childhood-onset genetic conditions. Those with an increased chance result are provided comprehensive genetic counseling support. Reproductive couples, recruiting healthcare providers, and study team members are also invited to complete surveys and/or interviews. In Phase 3, a mixed-methods analysis will be undertaken to assess the program outcomes, psychosocial implications and implementation considerations alongside an ongoing bioethical analysis and a health economic evaluation. Findings will inform the implementation of an ethically robust RGCS program.Alison D. Archibald ... Tristan Hardy ... et al. and The Mackenzie’s Mission Study Tea

Global optimisation-based control algorithms applied to boundary layer transition problems

Turbulent flow has a significantly higher drag than the corresponding laminar flow at the same flow conditions. The presence of turbulent flow over a large part of an aircraft therefore incurs a significant penalty of increased fuel consumption due to the extra thrust required. One possible way of decreasing the drag is to apply surface suction to delay the transition from laminar to turbulent flow. However, in order for the gain from the reduction in drag to outweigh the extra costs associated with the suction system, the suction must be distributed in an optimum, or near optimum, manner. In this paper two practical cases are considered. In the first of these a flat plate with panels whose positions are adjustable but do not overlap is treated. Since the cost function in this case is multi-modal, non-smooth and non-convex, methods for solving the optimisation problems necessary to design multi-panel suction systems based on direct search techniques are developed. In the second case considered the problem is that of linear distributed suction over the front part of an aerofoil. For this case, the computational load increases so significantly that in some cases it is not really feasible to continue the investigation using a single processor code. To overcome this, three parallel global optimisation algorithms are developed for the design of multi-panel suction systems on an aerofoil and it is shown that good solutions can be found efficiently

H/sub /spl infin// control of nonperiodic two-dimensional channel flow

This paper deals with finite-dimensional boundary control of the two-dimensional (2-D) flow between two infinite parallel planes. Surface transpiration along a few regularly spaced sections of the bottom wall is used to control the flow. Measurements from several discrete, suitably placed shear-stress sensors provide the feedback. Unlike other studies in this area, the flow is not assumed to be periodic, and spatially growing flows are considered. Using spatial discretization in the streamwise direction, frequency responses for a relevant part of the channel are obtained. A low-order model is fitted to these data and the modeling uncertainty is estimated. An H-infinity controller is designed to guarantee stability for the model set and to reduce the wall-shear stress at the channel wall. A nonlinear Navier-Stokes PDE solver was used to test the designs in the loop. The only assumption made in these simulations is that the flow is two dimensional. The results showed that, although the problem was linearized when designing the controller, the controller could significantly reduce fundamental 2-D disturbances in practice

Control law design for channel flow: 2D designs and 3D performance evaluation

The systems dealt with in How control problems are, in control terms, very complex, nonlinear and infinite dimensional, even if the fluid flow is comparatively simple. Plane Poiseuille flow, i.e. flow between two infinite parallel plates is one of the simplest and best understood cases of fluid dynamics. Controlling this flow is, however, still a very challenging problem, even if it is assumed that deviations from the steady-state are small enough for the governing equations to be linearized. Recent work has shown that robust control of 2D channel flow is possible without a spatial periodicity assumption.This paper will first execute an H-infinity based robust control law design for the 2D case and then proceed to the relatively open problem of assessing the resulting performance using a Navier Stokes CFD solver as a model of the 'real' process. The results in this second part will be on the representation (to ensure realistic results) and modelling of the disturbances used and the control of 3D disturbances