2,215 research outputs found

    Analysis, design, fabrication and testing of an optical tip clearance sensor

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    Analyses and the design, fabrication, and testing of an optical tip clearance sensor with intended application in aircraft propulsion control systems are reported. The design of a sensor test rig, evaluation of optical sensor components at elevated temperatures, sensor design principles, sensor test results at room temperature, and estimations of sensor accuracy at temperatures of an aircraft engine environment are discussed. Room temperature testing indicated possible measurement accuracies of less than 12.7 microns (0.5 mils). Ways to improve performance at engine operating temperatures are recommended. The potential of this tip clearance sensor is assessed

    A 4-D dataset for validation of crystal growth in a complex three-phase material, ice cream

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    Four dimensional (4D, or 3D plus time) X-ray tomographic imaging of phase changes in materials is quickly becoming an accepted tool for quantifying the development of microstructures to both inform and validate models. However, most of the systems studied have been relatively simple binary compositions with only two phases. In this study we present a quantitative dataset of the phase evolution in a complex three-phase material, ice cream. The microstructure of ice cream is an important parameter in terms of sensorial perception, and therefore quantification and modelling of the evolution of the microstructure with time and temperature is key to understanding its fabrication and storage. The microstructure consists of three phases, air cells, ice crystals, and unfrozen matrix. We perform in situ synchrotron X-ray imaging of ice cream samples using in-line phase contrast tomography, housed within a purpose built cold-stage (-40 to +20oC) with finely controlled variation in specimen temperature. The size and distribution of ice crystals and air cells during programmed temperature cycling are determined using 3D quantification. The microstructural evolution of three-phase materials has many other important applications ranging from biological to structural and functional material, hence this dataset can act as a validation case for numerical investigations on faceted and non-faceted crystal growth in a range of materials

    Feasibility of a randomized controlled trial of paediatric interdisciplinary pain management using home-based telehealth

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    Purpose: Chronic pain is common in adolescents. Evidence-based guidelines recommend interdisciplinary treatment, but access is limited by geography. The development of hybrid programs utilizing both face-to-face and videoconference treatment may help overcome this. We developed a 7-week hybrid pediatric interdisciplinary pain program (Hybrid-PIPP) and wished to compare it to individual face-to-face sessions (Standard Care). Our objective was to test the feasibility of a protocol that used a matched pair un-blinded randomized controlled design to investigate the efficacy and cost-effectiveness of the Hybrid-PIPP compared to Standard Care. Patients and Methods: Parent–adolescent dyads were recruited from tertiary pediatric clinics and matched by disability before randomization to minimize allocation bias. The adolescents (aged 11– 17) had experienced primary pain for > 3 months. Hybrid-PIPP involved 11 hrs of group therapy and 4 individual videoconference sessions. Standard care was provided by the same clinical team, using the same treatment model and similar intensity as the Hybrid-PIPP. The intention was to recruit participants for 3 Hybrid-PIPP groups with a comparison stream. Recruitment was ceased after 2 groups due to the high participant disability requiring more intensive intervention. Results: Eighteen dyads were screened and 13 randomized (7 Hybrid-PIPP, 6 Standard Care, 2 unsuitable, 3 unallocated when the study was stopped). The study met a priori feasibility criteria for staff availability; recruitment rate; treatment completion; and data collection. Global satisfaction ratings were similar in both streams (SC median 7, range 5– 9 and Hybrid-PIPP median 8.5, range 5– 10). Challenges were identified in both streams. A future modified Hybrid-PIPP was considered acceptable if the intensity is increased to manage the high level of disability. Standard care was considered inefficient. No adverse events were reported. Conclusion: The study determined that the protocol met a priori feasibility criteria, but to be practicable in a real world, health environment requires significant modifications

    Perceptions Of School By Two Teenage Boys With Asperger Syndrome And Their Mothers: A Qualitative Study

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    This qualitative study aimed to develop an understanding of the challenges faced by teenage boys with Asperger syndrome and their mothers. A case study approach was used to collect data from two 13-year-old boys who have Asperger syndrome and their mothers in Queensland, Australia. Data were collected through the use of semi¬structured interviews. The words of the boys and their mothers provide a valuable insight into the personal experiences and feelings of the par¬ticipants. An inductive approach to data analysis identified four themes: (1) developmental differences; (2) problems associated with the general characteristics of Asperger syndrome (i.e. communication and social difficulties, restricted range of interests, a need for routine); (3) stress; and (4) 'masquerading'. The first three themes relate strongly to the current literature, but the emergence of masquerading is of particular interest in developing a fuller understanding of the experiences of individuals with Asperger syndrome at school

    Universal Behaviour of the Superfluid Fraction and Tc of He-3 in 99.5% Open Aerogel

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    We have investigated the superfluid transition of He-3 in a 99.5% porosity silica aerogel. This very dilute sample shows behaviour intermediary between bulk He-3 and He-3 confined to the denser aerogels previously studied. We present data on both the superfluid transition temperature and the superfluid density and compare our results with previous measurements. Finally, we show that the suppression of the superfluid transition temperature and suppression of the superfluid density of He-3 in aerogel follow a universal relation for a range of aerogel samples.Comment: 4 pages, 5 figures; 1 new figure, minor change

    Abnormal Resting State fMRI Activity Predicts Processing Speed Deficits in First-Episode Psychosis

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    Little is known regarding the neuropsychological significance of resting state functional magnetic resonance imaging (rs-fMRI) activity early in the course of psychosis. Moreover, no studies have used different approaches for analysis of rs-fMRI activity and examined gray matter thickness in the same cohort. In this study, 41 patients experiencing a first-episode of psychosis (including N = 17 who were antipsychotic drug-naive at the time of scanning) and 41 individually age-and sex-matched healthy volunteers completed rs-fMRI and structural MRI exams and neuropsychological assessments. We computed correlation matrices for 266 regions-of-interest across the brain to assess global connectivity. In addition, independent component analysis (ICA) was used to assess group differences in the expression of rs-fMRI activity within 20 predefined publicly available templates. Patients demonstrated lower overall rs-fMRI global connectivity compared with healthy volunteers without associated group differences in gray matter thickness assessed within the same regions-of-interest used in this analysis. Similarly, ICA revealed worse rs-fMRI expression scores across all 20 networks in patients compared with healthy volunteers, with posthoc analyses revealing significant (
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