1,282 research outputs found

    On the interpretation of lateral manganin gauge stress measurements in polymers

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    Encapsulated wire-element stress gauges enable changes in lateral stress during shock loading to be directly monitored. However, there is substantial debate with regards to interpretation of observed changes in stress behind the shock front; a phenomenon attributed both to changes in material strength and shock- dispersion within the gauge-encapsulation. Here, a pair of novel techniques which both modify or remove the embedding medium where such stress gauges are placed within target materials have been used to try and inform this debate. The behavior of three polymeric materials of differing complexity was considered, namely polystyrene, the commercially important resin transfer moulding RTM 6 resin and a commercially available fat lard. Comparison to the response of embedded gauges has suggested a possible slight decrease in the absolute magnitude of stress. However, changing the encapsulation has no detectable effect on the gradient behind the shock in such polymeric systems

    The efficacy of problem-solving treatments after deliberate self-harm: meta-analysis of randomized controlled trials with respect to depression, hopelessness and improvement in problems

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    Background. Brief problem-solving therapy is regarded as a pragmatic treatment for deliberate self-harm (DSH) patients. A recent meta-analysis of randomized controlled trials (RCTs) evaluating this approach indicated a trend towards reduced repetition of DSH but the pooled odds ratio was not statistically significant. We have now examined other important outcomes using this procedure, namely depression, hopelessness and improvement in problems. Method. Six trials in which problem-solving therapy was compared with control treatment were identified from an extensive literature review of RCTs of treatments for DSH patients. Data concerning depression, hopelessness and improvement in problems were extracted. Where relevant statistical data (e.g. standard deviations) were missing these were imputed using various statistical methods. Results were pooled using meta-analytical procedures. Results. At follow-up, patients who were offered problem-solving therapy had significantly greater improvement in scores for depression (standardized mean difference =[minus sign]0·36; 95% CI [minus sign]0·61 to [minus sign]0·11) and hopelessness (weighted mean difference =[minus sign]3·2; 95% CI [minus sign]4·0 to [minus sign]2·41), and significantly more reported improvement in their problems (odds ratio = 2·31; 95% CI 1·29 to 4·13), than patients who were in the control treatment groups. Conclusions. Problem-solving therapy for DSH patients appears to produce better results than control treatment with regard to improvement in depression, hopelessness and problems. It is desirable that this finding is confirmed in a large trial, which will also allow adequate testing of the impact of this treatment on repetition of DSH

    Lateral stress evolution in chromium sulfide cermets with varying excess chromium

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    The shock response of chromium sulfide-chromium, a cermet of potential interest as a matrix material for ballistic applications, has been investigated at two molar ratios. Using a combustion synthesis technique allowed for control of the molar ratio of the material, which was investigated under near-stoichiometric (cermet) and excess chromium (interpenetrating composite) conditions, representing chromium:sulfur molar ratios of 1.15:1 and 4:1, respectively. The compacts were investigated via the plate-impact technique, which allowed the material to be loaded under a onedimensional state of strain. Embedded manganin stress gauges were employed to monitor the temporal evolution of longitudinal and lateral components of stress in both materials. Comparison of these two components has allowed assessment of the variation of material shear strength both with impact pressure/strain-rate and time for the two molar ratio conditions. The two materials exhibited identical material strength despite variations in their excess chromium content

    Modelling and characterization of cell collapse in aluminium foams during dynamic loading

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    Plate-impact experiments have been conducted to investigate the elastic–plastic behaviour of shock wave propagation and pore collapse mechanisms of closed-cell aluminium foams. FE modelling using a meso-scale approach has been carried out with the FE software ABAQUS/Explicit. A micro-computed tomography-based foam geometry has been developed and microstructural changes with time have been investigated to explore the effects of wave propagation. Special attention has been given to the pore collapse mechanism. The effect of velocity variations on deformation has been elucidated with three different impact conditions using the plate-impact method. Free surface velocity (ufs) was measured on the rear of the sample to understand the evolution of the compaction. At low impact velocities, the free-surface velocity increased gradually, whereas an abrupt rise of free-surface velocity was found at an impact velocity of 845 m/s with a copper flyer-plate which correlates with the appearance of shock. A good correlation was found between experimental results and FE predictions

    Measurement practices in hallucinations research

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    Introduction In several sub-fields of psychology, there has been a renewed focus on measurement practices. As far as we are aware, this has been absent in hallucinations research. Thus, we investigated (a) cross-study variation in how hallucinatory experiences are measured and (b) the reliability of measurements obtained using two tasks that are widely employed in hallucinations research. Method In Study 1, we investigated to what extent there was variation in how the Launay-Slade Hallucination Scale (LSHS) has been used across 100 studies. In Study 2, we investigated the reliability of the measurements obtained through source monitoring and signal detection tasks, using data from four recent publications. Materials/data are available at doi: 10.17605/osf.io/d3gnk/. Results In Study 1, we found substantial variation in how hallucinatory experiences were assessed using the LSHS and that descriptions of the LSHS were often incomplete in important ways. In Study 2, we reported a range of reliability estimates for the measurements obtained using source monitoring and signal discrimination tasks. Some measurements obtained using source monitoring tasks had unacceptably low levels of reliability. Conclusions Our findings suggest that suboptimal measurement practices are common in hallucinations research and we suggest steps researchers could take to improve measurement practices

    Critical friends: the role of non-executives on Whitehall boards

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    The psychological therapy preferences of patients who hear voices

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    Background Voice-hearing is a common, phenomenologically diverse, experience across different mental health diagnoses. Patient preferences for psychological therapies are helpful in informing treatment commissioning and provision, especially in the context of complex and variable experiences like voice-hearing. There is, however, very limited evidence as to the psychological therapy preferences of transdiagnostic voice-hearers. Methods Three-hundred and thirty-five voice hearers were recruited from secondary care NHS mental health services across England, between 2020 and 2022. Participants completed a questionnaire battery, involving a psychological therapy preference survey. Participants ranked their preferences across categories of practical, technical and relational therapy elements. Therapy preferences were examined using non-parametric ANOVAs and the significance of pairwise comparisons between different therapy elements. Results There were significant differences in all categories of preference elements. Clear hierarchies of preference were observed in therapy location, timing, delivery, and therapy approach. Preferences were evident, albeit with less clear vertical hierarchies, for number of sessions, mode, therapist qualities, and therapy focus, tasks and outcomes. Discussion Overall, participants expressed a preference for individual, face-to-face intervention of at least nine sessions, with a highly experienced therapist and a core focus on enhancing coping strategies for voice-hearing experiences

    The Enthusiast’s Eye: The Value of Unsanctioned Knowledge in Design Historical Scholarship

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    If design history research relies solely on institutionalized documentation and academic scholarship – that is, sanctioned knowledge – not only will its purview be limited to a very narrow segment of design culture, it will also lose out on a vast array of sources to valuable knowledge about our material environment produced by amateurs, collectors, and enthusiasts – what we in this article define as “unsanctioned knowledge.” Because of its dissociation with professional institutions and academic protocols and their – albeit admittedly utopian, but nonetheless upheld – ideals of objectivity, this type of knowledge is typically considered fundamentally subjective in nature and therefore of little or no relevance and value to academic scholarship. In this article, we argue that, to the contrary, design historical scholarship has much to gain from engaging more seriously with the unsanctioned knowledge represented by the enthusiast's eye
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