27,312 research outputs found

    Measurement of airfoil heat transfer coefficients on a turbine stage

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    The primary basis for heat transfer analysis of turbine airfoils is experimental data obtained in linear cascades. A detailed set of heat transfer coefficients was obtained along the midspan of a stator and a rotor in a rotating turbine stage. The data are to be compared to standard analyses of blade boundary layer heat transfer. A detailed set of heat transfer coefficients was obtained along the midspan of a stator located in the wake of a full upstream turbine stage. Two levels of inlet turbulence (1 and 10 percent) were used. The analytical capability will be examined to improve prediction of the experimental data

    What do we really know about infants who attend Accident and Emergency departments?

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    Aims: Accident and Emergency attendances continue to rise. Infants are disproportionately represented. This study examines the clinical reasons infants attend UK Accident and Emergency departments. Methods: A retrospective review of 6,667 infants aged less than one year attending Accident and Emergency at two district general hospitals in London from 1st April 2009 to 30th March 2010. All infants had been assigned to a diagnostic category by the medical coding department according to National Health Service (NHS) data guidelines, based on the clinical diagnoses stated in the medical records. The Accident and Emergency case notes of a random subsample of 10% of infants in each of the top five recorded diagnostic categories (n = 535) were reviewed in detail and audited against the standard national NHS data set. Results: The top 5 clinical diagnoses were ‘infectious diseases’, ‘gastrointestinal’, ‘respiratory’, ‘unclassifiable’ and ‘no abnormality detected’ (NAD). A third of infants were originally given a diagnosis of unclassifiable (21.5%) or NAD (11.5%). After detailed case-note review, we were able to reduce this to 9.7% (95% confidence interval (CI): 9.0, 10.4) and 8.8% (95% CI: 8.1, 9.5), respectively. Conclusion: This study demonstrates the importance of providing a clear clinical diagnosis and coding system for Accident and Emergency attendances and understanding that system fully. This would allow for better informed health service evaluation, planning and research as each of these relies on the interpretation of routine health-care data. Furthermore, the relatively high proportion (10%) of infants attending with no discernible underlying medical abnormality suggests the health needs of a significant proportion of infants attending Accident and Emergency departments may be better addressed by alternative service provision and/or improved education and support to parents

    B-Physics at the Tevatron (Proceedings of PASCOS2010)

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    We report on recent B-Physics results from the Tevatron. The topics covered include measurement of the polarization amplitudes in Bs0→ϕϕB_s^0 \to \phi \phi, the search for rare flavor-changing neutral-current decays, CP violation in Bs0→J/ψϕB_s^0 \to J/\psi \phi and semileptonic Bs0B_s^0 decays, and a new measurement of the like-sign asymmetry in dimuon events.Comment: 6 pages, proceedings paper, 16th International Symposium on Particles, Strings, and Cosmology, Valencia, Spain, July 19 - 23, 201

    The Reconstruction of Supersymmetric Theories at High Energy Scales

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    The reconstruction of fundamental parameters in supersymmetric theories requires the evolution to high scales, where the characteristic regularities in mechanisms of supersymmetry breaking become manifest. We have studied a set of representative examples in this context: minimal supergravity and a left--right symmetric extension; gauge mediated supersymmetry breaking; and superstring effective field theories. Through the evolution of the parameters from the electroweak scale the regularities in different scenarios at the high scales can be unravelled if precision analyses of the supersymmetric particle sector at e+ e- linear colliders are combined with analyses at the LHC.Comment: 36 pages, latex, 6 figure

    Psychosocial and educational outcomes of weight faltering in infancy in ALSPAC

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    OBJECTIVES: To investigate whether infants with weight faltering have impaired psychosocial and educational outcomes in later childhood. DESIGN: Follow-up of infants with weight faltering in a large UK cohort study. SETTING: The Avon Longitudinal Study of Parents and Children (ALSPAC). PARTICIPANTS: 11 534 term infants from ALSPAC with complete weight records. Weight gain (conditional on initial weight) was calculated for three periods: from birth to 8 weeks, 8 weeks to 9 months, and birth to 9 months. Cases of weight faltering were defined as those infants with a conditional weight gain below the 5th centile, and these were compared with the rest of the cohort as the control group. OUTCOMES: Between 6 and 11 years, social, emotional and behavioural development was measured by direct assessment of the children and parental and teacher report. Educational outcomes included Standardised Assessment Test results at 7 and 11 years and Special Educational Needs status at age 11. RESULTS: Differences seen on univariate analysis in attention, non-verbal accuracy, educational attainment and special educational needs became non-significant after adjustment for confounding. Children with weight faltering in infancy did not differ from controls on any measures of self-esteem, peer relationships, experience of bullying, social cognition, antisocial activities, anxiety, depression or behavioural problems. CONCLUSIONS: Weight faltering in early infancy was associated with poorer educational outcomes in later childhood, but these associations were explained by confounding. The subsequent psychosocial development of infants with slow weight gain was not different from that of their peers

    Benchmarking and optimisation of Simulink code using Real-Time Workshop and Embedded Coder for inverter and microgrid control applications

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    When creating software for a new power systems control or protection device, the use of auto-generated C code via MATLAB Simulink Real-Time Workshop and Embedded Coder toolboxes can be a sensible alternative to hand written C code. This approach offers the benefits of a simulation environment, platform independence and robust code. This paper briefly summarises recent experiences with this coding process including the pros and cons of such an approach. Extensive benchmarking activities are presented, together with descriptions of simple (but non-obvious) optimisations made as a result of the benchmarking. Examples include replacement of certain Simulink blocks with seemingly more complex blocks which execute faster. "S functions" are also designed for certain key algorithms. These must be fully "in-lined" to obtain the best speed performance. Together, these optimisations can lead to an increase in execution speed of more than 1.4x in a large piece of auto-generated C code. An example is presented, which carries out Fourier analysis of 3 signals at a common (variable) frequency. The overall speed improvement relative to the baseline is 2.3x, of which more than 1.4x is due to non-obvious improvements resulting from benchmarking activities. Such execution speed improvements allow higher frame rates or larger algorithms within inverters, drives, protection and control applications

    Digital multishaker modal testing

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    A review of several modal testing techniques is made, along with brief discussions of their advantages and limitations. A new technique is presented which overcomes many of the previous limitations. Several simulated experiments are included to verify the validity and accuracy of the new method. Conclusions are drawn from the simulation studies and recommendations for further work are presented. The complete computer code configured for the simulation study is presented

    A review of the mallet impact test for small scale explosive formulations

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    Presented at 19th Seminar on New Trends of Energetic Materials (NTREM 2016); 20-22/04/2016, Pardubice Czech RepublicDevelopment of new explosive formulations begins with the generation of only a few milligrams of material which is investigated using a number of small scale tests such as DSC, TGA, response to flame, mallet impact (mallet friction either glancing or direct blow) to determine whether the formulation is safe to scale up to 10 g. The latter of these tests, mallet impact, can be particularly subjective as the result is directly influenced by the operator carrying out the assessment. Not only can there be a change from one operator to another but there can also be a change in the force applied during each strike potentially leading to inconsistent results. This study highlights this encountered variation and assesses the load applied by a variety of operators with varying levels of explosive experience. This paper also proposes the use of a small scale laboratory based impact test which would provide improved confidence in the assessment of impact sensitiveness of explosive formulations and assist in justifying whether a formulation can be taken to the next scale. A small scale version of the BAM impact test (EMTAP Test 43) has been devised that allows the comparison of the sensitiveness of small scale formulations relative to RDX (8.7 J, EMTAP Test 43B) whilst also ensuring a reproducible result

    Polyunsaturated aldehyde production by a temporally varying field assemblage of diatoms in the San Juan Island Archipelago: can diatom metabolites affect microzooplankton grazing?

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    The success of diatoms in a wide range of global habitats, together with common observations of the post-bloom sinking of diatom biomass, indicates that this taxon has evolved a mechanism to reduce the largest loss process for phytoplankton in the ocean, microzooplankton grazing. Recent research has shown that polyunsaturated aldehydes (PUAs), lipid oxidation products generated by various species of diatoms, can reduce copepod fecundity and egg hatching success. This leads to the question of whether PUAs adversely affect the major global consumers of phytoplankton, microzooplankton. In the late spring to early fall 2007, I used the seawater dilution technique to quantify phytoplankton growth and microzooplankton grazing; at the same time I determined diatom and microzooplankton abundances and biomasses at Rosario Point, Orcas Island, WA (N 48° 38.614, W 122°52.750). In addition, I measured production of PUAs by the phytoplankton community to assess whether these chemicals functioned as chemical grazing deterrents, to look for novel PUA-producing diatom genera, and to evaluate environmental factors that potentially influenced PUA production. Four hydrographic structural change (HSC) events in the water column were identified during the spring-summer sampling period that probably reflected flushing by outside water masses. These events altered environmental conditions with distinct planktonic communities (termed community states) emerging during post-event water column stabilization. The first two community states were characterized by low nutrient concentrations with chlorophyll a between 6.5 and 13.1μg L-1 and several instances of negative growth and grazing rates. This suggested the release of an unidentified chemical by the Pseudo-nitzschia spp. dominated first community state that additionally had moderately high PUA production levels of 771-1520 μg PUA g C-1. Harmful algal bloom species Heterosigma akashiwo dominated the mid-summer community state with chlorophyll a reaching 10.45 μg chl L-1 and microzooplankton grazing rates reduced to nearly zero. Lastly, the diatom dominated mid-to-late summer community state reached 15.84 μg chl L-1 with Thalassiosira spp, Chaetoceros spp., and Skeletonema sp. all present as major constituents of the community that produced high PUA levels (1280- 3410 μg PUA g C-1). Each of the genera found in this study contain species that have previously been identified as producing PUA. Low phosphate concentrations within each of the PUA-producing communities appeared to influence production, as well as the presence of low light levels in the first community state that possibly increased PUAprecursor molecule formation. Furthermore, changes to growth rates in the \u3e20-μm (diatom) community with nutrient addition often occurred during PUA production, however this response by sampled diatom communities did not preclude PUA production. Community grazing on the \u3e20-μm size fraction was observed to decrease when PUA production was high. During the spring state negative grazing along with low microzooplankton biomass made interpretation difficult. During the mid-to-late summer state grazing was reduced to -0.02 to 0.08 d-1 with a large biomass of 143 to 180 μg C L-1 of non-feeding microzooplankton that included known diatom-feeding dinoflagellates Protoperidinium sp., 40 to 59 μm Gyro/Gymnodinium, and \u3e60-μm Gyro/Gymnodinium. With this reduced grazing, diatoms grew from 23.2 to 244 μg C L-1. Since diatom grazing genera of microzooplankton did not feed during the initiation and maintenance of the August bloom, my data suggests that PUA played a role in bloom initiation and allowed the diatom community to avoid predation
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