3,090 research outputs found

    Preliminary analysis of fuel tank impact

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    Following the accident involving the Air France Concorde in 2000 the effects of fluid structure interactions resulting from the impact of a fluid filled tank has become a cause for concern. The work reported here relates to the design of a series of experiments loosely based upon the Concorde incident which aimed to assess whether the probable failure mode in the Concorde accident could occur in land based vessels. Preliminary numerical analyses were undertaken for two of the nine cases that were investigated experimentally in which an empty tank was impacted by a projectile with a velocity of 14m/s and 21.9m/s Initial numerical results for the acceleration at two points on the tank surface and the deformation at the impact zone showed good agreement with test data. Future work is discussed including further numerical modelling incorporating fluid structure interactions for the analysis of the cases when the tank is partially full or completely full

    Towards Engaging Students in Curriculum Transformation: What are the Effective Characteristics of Rubrics?

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    Rubrics are tools commonly used by educators to accurately and consistently mark student assessments and communicate achieved learning outcomes. The teachers, having a clear understanding of the assessment\u27s intended learning outcomes, have traditionally constructed rubrics; however, an enhanced shared understanding of an assessment’s outcomes has the potential to be achieved if rubrics are developed as a collaboration between staff and students. Such practices provide potential for assessment, and its subsequent feedback, to be more highly valued by students not simply as an end-point, but rather as an opportunity for them to be active in their own learning, this becoming a curriculum transformation. This paper reports on the first phase of a project, funded by an Office for Learning and Teaching (OLT) Innovation and Discovery Grant: Owning the rubric: Student engagement in rubric design, use and moderation. Phase 1 of the project involved the identification of Effective Rubric Characteristics (ERCs) through a literature-evidenced approach that subsequently informed the formation of an Effective Rubrics Characteristics Questionnaire (ERCQ). The ERCQ was piloted with a small group of experienced users and then it was administered to a group of assessment and rubric experts to establish the key attributes of effective rubrics using a modified Delphi technique

    Tuberculous meningitis in children: reducing the burden of death and disability

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    Tuberculous meningitis disproportionately affects young children. As the most devastating form of tuberculosis, it is associated with unacceptably high rates of mortality and morbidity even if treated. Challenging to diagnose and treat, tuberculous meningitis commonly causes long-term neurodisability in those who do survive. There remains an urgent need for strengthened surveillance, improved rapid diagnostics technology, optimised anti-tuberculosis drug therapy, investigation of new host-directed therapy, and further research on long-term functional and neurodevelopmental outcomes to allow targeted intervention. This review focuses on the neglected field of paediatric tuberculous meningitis and bridges current clinical gaps with research questions to improve outcomes from this crippling disease

    THE DEVELOPMENT OF THE CHILDREN'S BEHAVIOR QUESTIONNAIRE, TEACHER VERSION (CBQ-T)

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    Information is provided about the development of a teacher version of the Children's Behavior Questionnaire Short Form (CBQ Short Form; Putnam & Rothbart, 2006). The CBQ Short Form, designed for caregivers, was modified by changing the item wording for the preschool classroom and is termed the CBQ, Teacher Version (CBQ-T). Both measures were administered to the caregivers and teachers of preschoolers ages 3 to 6 years. The CBQ-T was found to be as reliable as the CBQ Short Form with two scales falling short of adequate internal consistency. Few correlations were found between parents and teachers in accord with literature documenting low to moderate agreement between the two raters. Several temperament scales were correlated with age for parents and teachers, none were correlated with gender as rated by parents, and several were correlated with gender as rated by teachers. Further validation of the CBQ-T with varying populations would be beneficial

    Calculation of the Phase Behavior of Lipids

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    The self-assembly of monoacyl lipids in solution is studied employing a model in which the lipid's hydrocarbon tail is described within the Rotational Isomeric State framework and is attached to a simple hydrophilic head. Mean-field theory is employed, and the necessary partition function of a single lipid is obtained via a partial enumeration over a large sample of molecular conformations. The influence of the lipid architecture on the transition between the lamellar and inverted-hexagonal phases is calculated, and qualitative agreement with experiment is found.Comment: to appear in Phys.Rev.

    Spin- and angle-resolved photoemission studies of the electronic structure of Si(110)"16x2" surfaces

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    The electronic structure of Si(110)"16 x 2" double-domain, single-domain and 1 x 1 surfaces have been investigated using spin- and angle-resolved photoemission at sample temperatures of 77 K and 300 K. Angle-resolved photoemission was conducted using horizontally- and vertically-polarised 60 eV and 80 eV photons. Band-dispersion maps revealed four surface states (S1S_1 to S4S_4) which were assigned to silicon dangling bonds on the basis of measured binding energies and photoemission intensity changes between horizontal and vertical light polarisations. Three surface states (S1S_1, S2S_2 and S4S_4), observed in the Si(110)"16 x 2" reconstruction, were assigned to Si adatoms and Si atoms present at the edges of the corrugated terrace structure. Only one of the four surface states, S3S_3, was observed in both the Si(110)"16 x 2" and 1 x 1 band maps and consequently attributed to the pervasive Si zigzag chains that are components of both the Si(110)"16 x 2" and 1 x 1 surfaces. A state in the bulk-band region was attributed to an in-plane bond. All data were consistent with the adatom-buckling model of the Si(110)"16 x 2" surface. Whilst room temperature measurements of PyP_y and PzP_z were statistically compatible with zero, PxP_x measurements of the enantiomorphic A-type and B-type Si(110)"16 x 2" surfaces gave small average polarisations of around 1.5\% that were opposite in sign. Further measurements at 77 K on A-type Si(110)"16 x 2" surface gave a smaller value of +0.3\%. An upper limit of 1%\sim1\% may thus be taken for the longitudinal polarisation.Comment: Main paper: 12 pages and 11 figures. Supplemental information: 5 pages and 2 figure

    Sensory adaptation in naive peripheral CD4 T cells

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    T cell receptor interactions with peptide/major histocompatibility complex (pMHC) ligands control the selection of T cells in the thymus as well as their homeostasis in peripheral lymphoid organs. Here we show that pMHC contact modulates the expression of CD5 by naive CD4 T cells in a process that requires the continued expression of p56(lck). Reduced CD5 levels in T cells deprived of pMHC contact are predictive of elevated Ca(2)+ responses to subsequent TCR engagement by anti-CD3 or nominal antigen. Adaptation to peripheral pMHC contact may be important for regulating naive CD4 T cell responsiveness

    New type of microengine using internal combustion of hydrogen and oxygen

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    Microsystems become part of everyday life but their application is restricted by lack of strong and fast motors (actuators) converting energy into motion. For example, widespread internal combustion engines cannot be scaled down because combustion reactions are quenched in a small space. Here we present an actuator with the dimensions 100x100x5 um^3 that is using internal combustion of hydrogen and oxygen as part of its working cycle. Water electrolysis driven by short voltage pulses creates an extra pressure of 0.5-4 bar for a time of 100-400 us in a chamber closed by a flexible membrane. When the pulses are switched off this pressure is released even faster allowing production of mechanical work in short cycles. We provide arguments that this unexpectedly fast pressure decrease is due to spontaneous combustion of the gases in the chamber. This actuator is the first step to truly microscopic combustion engines.Comment: Paper and Supplementary Information (to appear in Scientific Reports
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