The Application of an Unfactored Method to the Simulation of Nonlinear Aerofoil Responses: Part I - Verification for Inviscid Flows. G.U. Aero Report 9432

An unfactored solution method developed for the Navier-Stokes equations is applied to study the nonlinear aeroelastic response of an aerofoil. A loosely coupled approach is adopted with the structural equations and the flow equations being solved in sequence. The flow solver efficiency is compared with the standard ADI method and the results are compared with previous computations for the NACA64A006 aerofoil

Changes in positive and negative voice content in cognitive‐behavioural therapy for distressing voices

Objective People who experience distressing voices frequently report negative (e.g. abusive or threatening) voice content and this is a key driver of distress. There has also been recognition that positive (e.g. reassuring, or guiding) voice content contributes to better outcomes. Despite this, voice content has been neglected as a standalone outcome in evaluations of psychological therapies for distressing voices. We aimed to examine whether a modular cognitive-behavioural therapy (CBT) intervention for voices led to changes in negative and positive voice content. Design/Methods In a naturalistic, uncontrolled pre- and post- service evaluation study, 32 clients at an outpatient psychology service for distressing voices received eight sessions of CBT for distressing voices and completed self-report measures of negative and positive voice content at pre-, mid- and post- therapy. Results There was no significant change in positive voice content. There was no significant change in negative voice content from pre- to post-therapy; however, there was a significant change in negative voice content between mid and post-treatment in which the cognitive therapy component was delivered. The CBT treatment was also associated with significant changes in routinely reported outcomes of voice-related distress and voice severity. Conclusions The cognitive component of CBT for distressing voices may be associated with changes in negative, but not positive, voice content. There may be benefit to enhancing these effects by developing treatments targeting specific processes involved in negative and positive voice content and further exploring efficacy in well-powered, controlled trials with more comprehensive measures of voice content

CFD Analysis of Rotor-Fuselage Aerodynamics based on a Sliding Mesh Algorithm

Rotor-fuselage interaction is central to the design and performance analysis of helicopters. However, regardless of its significance this problem is not well-studied and few CFD works have so far been published. In this paper, a method is put forward to allow CFD computations of rotor-fuselage problems using a sliding mesh to interface the rotor and fuselage regions. A sliding plane forms a boundary between a CFD mesh around the fuselage and a rotor-fixed CFD mesh which has to be rotated to account for the motion of the rotor blades. CFD meshes adjacent to a sliding plane do not necessarily have matching nodes or even the same number of cell-faces. This poses a problem of interpolation between CFD meshes and, in addition, the employed algorithms should have small CPU overhead. The properties of this method are assessed and validation results are presented for several flow case

From villains to victims: experiencing illness in Siberian exile

This essay presents the subjective experience of life and sickness for the punished in late Imperial Siberia, and the distinctions the punished made between legitimate and illegitimate forms of punishment. The essay also explores state policies towards the sick punished, and explores how different levels of the Tsarist administration and local Siberian society dealt with the challenge of sick and decrepit exiles. It argues that conditions in Siberian prisons were, in general, worse than those in European Russian prisons in the post-1906 period, and that the experience of exile in eastern Siberia placed it among the most difficult locations for exile. Though neither the state nor the punished regarded illness as an integral part of their punishment, the prevalence of illness and disease compounded the cruelty of sentences

No meditation-related changes in the auditory N1 during first-time meditation

Recent studies link meditation expertise with enhanced low-level attention, measured through auditory event-related potentials (ERPs). In this study, we tested the reliability and validity of a recent finding that the N1 ERP in first-time meditators is smaller during meditation than non-meditation – an effect not present in long-term meditators. In the first experiment, we replicated the finding in first-time meditators. In two subsequent experiments, we discovered that this finding was not due to stimulus-related instructions, but was explained by an effect of the order of conditions. Extended exposure to the same tones has been linked with N1 decrement in other studies, and may explain N1 decrement across our two conditions. We give examples of existing meditation and ERP studies that may include similar condition order effects. The role of condition order among first-time meditators in this study indicates the importance of counterbalancing meditation and non-mediation conditions in meditation studies that use event-related potentials

Pre-stressed advanced fibre reinforced composites fabrication and mechanical performance

Advanced composite materials have high strength-to-weight ratios, corrosion resistance and durability and are extensively used in aerospace, energy and defence industries. This research concentrates on minimising the process-induced residual stresses, and improving the fibre alignment of composites by employing a fibre prestress methodology. A novel flat-bed fibre prestress methodology for autoclave processing of composites was developed. This research investigates the effect of fibre prestress on 1) residual stresses, 2) fibre alignment, 3) static tensile and compression properties and 4) fatigue behaviour of composites. Experimental results show that this prestress methodology, on a 16-ply unidirectional E-glass/ 913 epoxy composite, reduces the residual strain of the composite from –600 µε to approximately zero for a prestress of 108 MPa. The strains measured from optical fibre sensors were in close agreement with those obtained using strain gauge. The results from fibre alignment studies showed that fibre prestressing improved the fibre alignment from 20% of fibres aligned to 0 ° degree in non-prestressed composites to 75% of fibres aligned to 0 ° degree in 108 MPa prestressed composites. Findings have shown that prestressing is beneficial to the static compressive and tensile performance of composites. The results show that fibre prestressing improves the fatigue life and resistance to stiffness degradation in the low stress level fatigue region. Also a change in static and fatigue damage mechanism was observed. The improvement in the static and fatigue properties is due to the reduction in residual stresses and fibre waviness. Overall the fibre prestressing methodology enhances the performance of composites by increasing the resistance to static and fatigue loading. The thesis also suggests that there is an existence of prestress limits to retain optimal material performance.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Meditation and auditory attention: An ERP study of meditators and non-meditators

The findings of a study by Cahn and Polich (2009) suggests that there is an effect of a meditative state on three event-related potential (ERP) brain markers of “low-level” auditory attention (i.e., acoustic representations in sensory memory) in expert meditators: the N1, the P2, and the P3a. The current study built on these findings by examining trait and state effects of meditation on the passive auditory mismatch negativity (MMN), N1, and P2 ERPs. We found that the MMN was significantly larger in meditators than non-meditators regardless of whether they were meditating or not (a trait effect), and that N1 amplitude was significantly attenuated during meditation in non-meditators but not expert meditators (an interaction between trait and state). These outcomes suggest that low-level attention is superior in long-term meditators in general. In contrast, low-level attention is reduced in non-meditators when they are asked to meditate for the first time, possibly due to auditory fatigue or cognitive overload

Micro-machining techniques for the fabrication of fibre Fabry-Perot sensors

Fabry-Perot optical fibre sensors have been used extensively for measuring a variety of parameters such as strain, temperature, pressure and vibration. Conventional extrinsic fibre Fabry-Perot sensors are associated with problems such as calibration of the gauge length of each individual sensor, their relatively large size compared to the diameter of optical fibre and a manual manufacturing method that leads to poor reproducibility. Therefore, new designs and fabrication techniques for producing fibre Fabry-Perot sensors are required to address the problems of extrinsic fibre Fabry-Perot sensors. This thesis investigates hydrofluoric acid etching and F2-laser micro-machining of optical fibres to produce intrinsic Fabry-Perot cavities. Chemical etching of single mode fused silica fibres produced cavities across the core of the fibres due to preferential etching of the doped-region. Scanning electron microscope, interferometric surface profiler and CCD spectrometer studies showed that the optical quality of the etched cavities was adequate to produce Fabry-Perot interference. Controlled fusion splicing of etched fibres produced intrinsic Fabry-Perot cavities. These sensors were surface-mounted on composite coupons and their response to applied strain was studied using low coherence interferometry. These sensors showed linear and repeatable response with the strain measured by the electrical resistance strain gauges. To carry out F2-laser micro-machining of fused silica and sapphire substrates, a micro-machining station was designed and constructed. This involved the design of illumination optics for 157 nm laser beam delivery, the design and construction of beam delivery chamber, target alignment and monitoring systems. Ablation of fused silica and sapphire disks was carried out to determine ablation parameters suitable for micro-machining high aspect ratio microstructures that have adequate optical quality to produce Fabry-Perot interference. Cavities were micro-machined through the diameter of SMF 28 and SM 800 fibres at different energy densities. CCD interrogation of these intrinsic fibre cavities ablated at an energy density of 25 x 10 4 Jm -2 produced Fabry-Perot interference fringes. The feasibility of micro-machining high aspect ratio cavities at the cleaved end-face of the fused silica fibres and through the diameter of sapphire fibres was demonstrated. A technique based on in-situ laser-induced fluorescence monitoring was developed to determine the alignment of optical fibres and ablation depth during ablation through the fibre diameter. Ablation of cavities through the diameter of fibre Bragg gratings showed that the heat-generated inside the cavity during ablation had no effect on the peak reflection and the integrity of core and cladding of the fibre. Finally, a pH-sensor, a chemical sensor based on multiple cavities ablated in multimode fibres and a feasible design for pressure sensor fabrication based on ablated cavity in a single mode fibre were demonstrated.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Training school teachers to promote mental and social well-being in low and middle income countries : lessons to facilitate scale-up from a participatory action research trial of youth first in India

Mental and social wellbeing (MSWB) promotion programs could improve mental health and other outcomes for youth in Low and Middle Income Countries (LMICs). Unfortunately, few such programs have progressed to scale-up and few studies have detailed processes and considerations that could facilitate doing so. This study begins to fill these gaps, describing key findings from training and supporting government middle school teachers to deliver the Youth First Resilience Curriculum, a MSWB promotion program, in Bihar, India. We conducted a Participatory Action Research trial of the resilience curriculum among 792 middle school youth and 55 teachers at 15 government schools. Participant-observations, exit interviews, and group discussions were conducted and analyzed via multiple rounds of coding to generate thematic findings. A number of schools showed relatively high levels of interest, session reliability and fidelity, student interaction and teacher facilitative abilities, but there was great variation within the sample. Three leverage points emerged to facilitate future scale-up: factors for successful site assessment and program initiation, supporting teacher success via interest and motivation, and responding to varied teacher skill levels. These points represent critical focus areas for practitioners and policy-makers as more MSWB promotion programs begin to scale in LMICs.peer-reviewe