THE EFFECT OF RESIDUAL STRESS AND MICROSTRUCTURE ON DISTORTION IN THIN WELDED STEEL PLATES

ABSTRACT The current trend in ship construction is to reduce the thickness of the ship panels, in order to minimize weight and maximize vessel speed. The ship panels of interest consist of 4 mm thick butt welded plates. This reduction in panel thickness may lead to excessive plate distortion during welding, resulting in significant additional costs during assembly. A ferritic-pearlitic DH-36 steel is used, in which phase transformations during welding may affect the distortion and stress states observed. Two large plates, representative of ship panels, have been butt welded using a metal inert gas (MIG) process. The temperature histories have been recorded during welding and the resulting distortion profile has been obtained using digital photography. Neutron diffraction measurements have been performed to determine the residual stress state in the plates before welding, due to e.g. processing and laser cutting, and after butt welding of the plates. Reference matchsticks from the weld, heat affected zone (HAZ) and parent plate have been taken from similar locations in nominally identical plates and measured to obtain the strain/stress free lattice parameter, a 0 . A Rietveld analysis has been performed on the diffraction data. Post welding, hardness surveys have indicated the microstructural variation in the weld, parent plate and HAZ. Results from these on-going studies are presented which identify the key factors responsible for thin plate distortion

Enhanced Visual Temporal Resolution in Autism Spectrum Disorders

Cognitive functions that rely on accurate sequencing of events, such as action planning and execution, verbal and nonverbal communication, and social interaction rely on well-tuned coding of temporal event-structure. Visual temporal event-structure coding was tested in 17 high-functioning adolescents and adults with autism spectrum disorder (ASD) and mental- and chronological-age matched typically-developing (TD) individuals using a perceptual simultaneity paradigm. Visual simultaneity thresholds were lower in individuals with ASD compared to TD individuals, suggesting that autism may be characterised by increased parsing of temporal event-structure, with a decreased capability for integration over time. Lower perceptual simultaneity thresholds in ASD were also related to increased developmental communication difficulties. These results are linked to detail-focussed and local processing bias

A puzzle form of a non-verbal intelligence test gives significantly higher performance measures in children with severe intellectual disability

<p>Abstract</p> <p>Background</p> <p>Assessment of 'potential intellectual ability' of children with severe intellectual disability (ID) is limited, as current tests designed for normal children do not maintain their interest. Thus a <it>manual puzzle </it>version of the Raven's Coloured Progressive Matrices (RCPM) was devised to appeal to the attentional and sensory preferences and language limitations of children with ID. It was hypothesized that performance on the book and manual puzzle forms would not differ for typically developing children but that children with ID would perform better on the puzzle form.</p> <p>Methods</p> <p>The first study assessed the validity of this puzzle form of the RCPM for 76 typically developing children in a test-retest crossover design, with a 3 week interval between tests. A second study tested performance and completion rate for the puzzle form compared to the book form in a sample of 164 children with ID.</p> <p>Results</p> <p>In the first study, no significant difference was found between performance on the puzzle and book forms in typically developing children, irrespective of the order of completion. The second study demonstrated a significantly higher performance and completion rate for the puzzle form compared to the book form in the ID population.</p> <p>Conclusion</p> <p>Similar performance on book and puzzle forms of the RCPM by typically developing children suggests that both forms measure the same construct. These findings suggest that the puzzle form does not require greater cognitive ability but demands sensory-motor attention and limits distraction in children with severe ID. Thus, we suggest the puzzle form of the RCPM is a more reliable measure of the non-verbal mentation of children with severe ID than the book form.</p

Measuring Reciprocity in High Functioning Children and Adolescents with Autism Spectrum Disorders

Few instruments have been developed that measure impairments in reciprocity, a defining feature of autism. We introduce a new test assessing the quality of reciprocal behaviour: the interactive drawing test (IDT). Children and adolescents (n = 49) with and without high functioning autism spectrum disorders (HFASD) were invited to collaborate with an experimenter in making a joint drawing. Within both groups the performance on collaborative reciprocity improved with age. However, compared to the control group, HFASD participants showed less collaborative and more basic reciprocal behaviour and preferred to draw their own objects. They were less tolerant of the experimenter’s input as well. Performance on the IDT was independent of estimated verbal IQ. Reciprocal behaviour in self-initiated objects corresponded with more parental reported autistic traits, while reciprocal behaviour in other-initiated objects corresponded with less autistic traits. The findings of this study suggest that IDT is a promising instrument to assess reciprocity

Using time perception to explore implicit sensitivity to emotional stimuli in autism spectrum disorder

Establishing whether implicit responses to emotional cues are intact in autism spectrum disorder (ASD) is fundamental to ascertaining why their emotional understanding is compromised. We used a temporal bisection task to assess for responsiveness to face and wildlife images that varied in emotional salience. There were no significant differences between an adult ASD and comparison group, with both showing implicit overestimation of emotional stimuli. Further, there was no correlation between overestimation of emotional stimuli and autistic traits in undergraduate students. These data do not suggest a fundamental insensitivity to the arousing content of emotional images in ASD, or in individuals with a high degree of autistic traits. The findings have implications for understanding how emotional stimuli are processed in ASD

Parent-Of-Origin Effects in Autism Identified through Genome-Wide Linkage Analysis of 16,000 SNPs

Autism is a common heritable neurodevelopmental disorder with complex etiology. Several genome-wide linkage and association scans have been carried out to identify regions harboring genes related to autism or autism spectrum disorders, with mixed results. Given the overlap in autism features with genetic abnormalities known to be associated with imprinting, one possible reason for lack of consistency would be the influence of parent-of-origin effects that may mask the ability to detect linkage and association.We have performed a genome-wide linkage scan that accounts for potential parent-of-origin effects using 16,311 SNPs among families from the Autism Genetic Resource Exchange (AGRE) and the National Institute of Mental Health (NIMH) autism repository. We report parametric (GH, Genehunter) and allele-sharing linkage (Aspex) results using a broad spectrum disorder case definition. Paternal-origin genome-wide statistically significant linkage was observed on chromosomes 4 (LOD(GH) = 3.79, empirical p<0.005 and LOD(Aspex) = 2.96, p = 0.008), 15 (LOD(GH) = 3.09, empirical p<0.005 and LOD(Aspex) = 3.62, empirical p = 0.003) and 20 (LOD(GH) = 3.36, empirical p<0.005 and LOD(Aspex) = 3.38, empirical p = 0.006).These regions may harbor imprinted sites associated with the development of autism and offer fruitful domains for molecular investigation into the role of epigenetic mechanisms in autism

Typical auditory-motor and enhanced visual-motor temporal synchronization in adults with Autism Spectrum Disorder

The perception of subsecond durations in adults with Autism Spectrum Disorder (hereafter ‘autism’; n=25 Experiment 1, n=21 Experiment 2) and matched typical adults (n=24 Experiment 1, n=22 Experiment 2) was examined by requiring participants to perform an action in time with auditory (Experiment 1) or visual (Experiment 2) events. Individuals with autism performed comparably to typical participants in the auditory task and exhibited less temporal error relative to their typical counterparts in the visual task. These findings suggest that perception of subsecond intervals is intact in autism, if not enhanced. Results support recent Bayesian theories of enhanced visual-perceptual precision in people with autism, and extend empirical support into the precision of subsecond temporal estimates

The DREAM Dataset: Supporting a data-driven study of autism spectrum disorder and robot enhanced therapy

We present a dataset of behavioral data recorded from 61 children diagnosed with Autism Spectrum Disorder (ASD). The data was collected during a large-scale evaluation of Robot Enhanced Therapy (RET). The dataset covers over 3000 therapy sessions and more than 300 hours of therapy. Half of the children interacted with the social robot NAO supervised by a therapist. The other half, constituting a control group, interacted directly with a therapist. Both groups followed the Applied Behavior Analysis (ABA) protocol. Each session was recorded with three RGB cameras and two RGBD (Kinect) cameras, providing detailed information of children’s behavior during therapy. This public release of the dataset comprises body motion, head position and orientation, and eye gaze variables, all specified as 3D data in a joint frame of reference. In addition, metadata including participant age, gender, and autism diagnosis (ADOS) variables are included. We release this data with the hope of supporting further data-driven studies towards improved therapy methods as well as a better understanding of ASD in general.CC BY 4.0DREAM - Development of robot-enhanced therapy for children with autism spectrum disorders