Effect of NbC and TiC precipitation on shape memory in an iron-based alloy

This paper examines the effects of TiC and NbC precipitation and prior cold rolling on the shape memory behaviour of an iron-based alloy. A precipitate-free alloy was used as a reference to investigate the relative contributions of prior-deformation and precipitation on shape memory. Heat treatment of the Nb- and Ti-containing alloys at 700 °C and 800 °C resulted in carbide precipitates between 120 nm and 220 nm in diameter. Bend testing of these samples showed a marginal increase in shape memory compared to the precipitate-free alloy. Under these conditions TiC precipitation exhibited slightly better shape memory than for NbC. However, this small increase was over-shadowed by the marked increase in shape memory that can be produced by subjecting the alloys to cold rolling followed by recovery annealing. When processed in this way, fine carbides are formed in the Ti- and Nb-containing alloys during the heat treatment. For particles >25 nm in diameter the shape memory is unaffected, but, it was found that small <5 nm particles have a detrimental effect on shape memory due to pinning of the martensite plates, thereby inhibiting their reversion to austenite. The optimum shape memory was observed in the precipitate-free alloy after cold rolling and recovery annealing.

Optimization of alloy design and hot rolling conditions for shape memory in Fe–Mn–Si-based alloys

The effect of composition and hot rolling conditions on the shape memory effect (SME) in the Fe–Mn–Si-based system has been studied to obtain improved shape memory without the need to rely on “training”. It has been found that the texture is not markedly affected by rolling conditions, and texture is therefore not a major factor in explaining variations in SME with processing conditions. Decreasing the pre-deformation temperature to below the Ms was found to have a beneficial effect on shape memory. It was found that the best SME was achieved in an alloy that had Ms just above room temperature, and had been processed by hot rolling followed by recovery annealing. Alloys of different compositions exhibited different optimum rolling temperatures for maximum shape memory performance.

Effect of second-phase particles on shape memory in Fe-Mn-Si-based alloys

The shape memory behaviour of two Fe–Mn–Si-based alloys has been investigated. One alloy was a reference alloy, and the other alloy was
similar in composition except that it contained 0.55 wt% Ti. Following solution treatment and quenching, strip samples were subjected to three types
of treatments; isothermal holding, cold rolling followed by isothermal holding, and hot rolling followed by isothermal holding. These treatments
resulted in the formation of intermetallic precipitates in the Ti-containing alloy, while the reference alloy remained precipitate-free. In comparing
the shape memory of the reference and the particle-containing alloy after identical heat treatments, it was found that the formation of precipitates
had a beneficial effect on the shape memory in all cases. In general, the larger precipitates caused a larger increase in the shape memory. The effect
of particle size on shape memory has been analysed using the current data and published results for a range of precipitate types.

Family correlates of fruit and vegetable consumption in children and adolescents : a systematic review

Objectives To review associations between the family environment and young people’s fruit and vegetable consumption.

Design A systematic review. Published English-language (n 60) papers were identified using electronic databases and manual searches of personal files and reference lists. Observational research reporting a measure of fruit/vegetable intake for children (aged 6–11 years) and/or adolescents (aged 12–18 years) and at least one potential family correlate of dietary intake was included.

Results Parental modelling and parental intake were consistently and positively associated with children’s fruit and fruit, juice and vegetable (FJV) consumption. There were also positive associations between home availability, family rules and parental encouragement and children’s fruit and vegetable consumption. Parental intake was positively associated with adolescents’ fruit and vegetable consumption. There were also positive associations between parental occupational status and adolescent fruit consumption and between parental education and adolescents’ FJV consumption.

Conclusions Our findings highlight the importance of targeting the family environment for the promotion of healthy eating behaviours among children and adolescents. Future interventions should encourage parents to be positive role models by targeting parental intake and to create a supportive home environment through increased encouragement and availability of fruits and vegetables and employing rules to govern eating behaviours. For adolescents, indicators of family circumstances (e.g. parental education) should be used to identify target groups for interventions aimed at promoting healthy eating.

PTSD symptomatology in children and adolescents : treatment development and evaluation

This thesis developed, implemented and evaluated a cognitive-behavioural group treatment programme for children and adolescents experiencing symptoms of PTSD (Post-traumatic stress disorder). Results of the study indicate that symptoms of sleep disturbance and flashbacks, reduced markedly in the participants, providing a useful tool in reducing synptoms experiences by individuals exposed to trauma. The Professional portfolio presents four case studies that demonstrate the clinical application of the affect of chronic illness on the psychological adjustment of the sufferer and their families.

Analysis of children's merging errors

Array

An investigation of the boundaries of young children's reporting of non-experienced events

This thesis explored young children's reporting of non-experienced (false) events. It demonstrated that children can be led to provide convincing reports of plausible and implausible false events within both narrow and broad contextual frameworks. Further, it showed that investigative interviewers utilise questioning techniques that could elicit false-event reports from children.

Effects of physical activity on depression and anxiety in children

This thesis study examined the direct and indirect effects of physical activity, self-efficacy and peer relations in depression and anxiety in children. No direct relationships between physical activity and symptoms of depression or anxiety were found for either sex. The portfolio, using four clinical health psychology case studies, provides an illustration of the clinical application of the transtheoretical model to four different health issues.

Effects of repeated interviews on children's recall of an event

The results of three studies suggest that repeated interviews assist in retaining information over a 6 week interval without increasing suggestibility. In addition prompting was also efficient in retaining information over 6 weeks. The implications of this study were that repeated interviews at intervals less than 4 weeks, could assist children to improve recall at a court appearance.

Relationships between measures of fitness, physical activity, body composition and vascular function in children

Background : The prevalence of obesity and physical inactivity in Western countries has increased rapidly. Both are modifiable risk factors for cardiovascular disease. Atherosclerosis begins in childhood and endothelial dysfunction is its earliest detectable manifestation.

Methods : We assessed flow-mediated dilation (FMD) in 129 children (75 female; 10.3 + 0.3 yrs; 54 male; 10.4; 0.3 yrs). FMD was normalised for differences in the eliciting shear rate stimulus between subjects (SR_AUC). Fitness was assessed as peak oxygen uptake during an incremental treadmill exercise test (VO₂peak). Body composition was measured using a dual-energy X-ray absorptiometry (DEXA) scan. Physical activity (PA) was assessed using Actigraph accelerometers. The cohort was split into tertiles according to FMD% and also FMD% corrected for SR_AUC to gain insight into the determinants of vascular function.

Results : Across the cohort, significant correlations were observed between FMD%/SR_AUC and DEXA percentage fat (r = &minus;0.23, p = 0.009) and percentage lean mass (r = 0.21, p = 0.008), and also with PA performed at moderate-to-high intensity (r = 0.363, p = 0.001). For children in the lowest FMD%/SR_AUC tertile, a stronger relationship with all PA measures was observed, particularly with high intensity PA (r = 0.572, P = 0.003). Regression analysis revealed that high intensity PA was the only predictor of impaired FMD%/SR_AUC.

Conclusions : These data suggest that traditional risk factors for CHD in adult populations impact upon vascular function in young people. Furthermore, it appears that individuals with impaired FMD may benefit from performing high intensity PA, whereas no relationships exist between FMD and lower intensities of PA or between PA and FMD in those subjects who possess preserved vascular function a priori.