1,060 research outputs found

    Design and fabrication of solar cell modules

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    A program conducted for design, fabrication and evaluation of twelve silicon solar cell modules is described. The purpose of the program was to develop a module design consistent with the requirements and objectives of JPL specification and to also incorporate elements of new technologies under development to meet LSSA Project goals. Module development emphasized preparation of a technically and economically competitive design based upon utilization of ion implanted solar cells and a glass encapsulation system. The modules fabricated, tested and delivered were of nominal 2 X 2 foot dimensions and 20 watt minimum rating. Basic design, design rationale, performance and results of environmental testing are described

    Development and validation of a piloted simulation of a helicopter and external sling load

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    A generalized, real time, piloted, visual simulation of a single rotor helicopter, suspension system, and external load is described and validated for the full flight envelope of the U.S. Army CH-54 helicopter and cargo container as an example. The mathematical model described uses modified nonlinear classical rotor theory for both the main rotor and tail rotor, nonlinear fuselage aerodynamics, an elastic suspension system, nonlinear load aerodynamics, and a loadground contact model. The implementation of the mathematical model on a large digital computing system is described, and validation of the simulation is discussed. The mathematical model is validated by comparing measured flight data with simulated data, by comparing linearized system matrices, eigenvalues, and eigenvectors with manufacturers' data, and by the subjective comparison of handling characteristics by experienced pilots. A visual landing display system for use in simulation which generates the pilot's forward looking real world display was examined and a special head up, down looking load/landing zone display is described

    New insights into the size and stoichiometry of the plasminogen activator inhibitor type-1·vitronectin complex

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    Plasminogen activator inhibitor-type 1 (PAI-1) is the primary inhibitor of endogenous plasminogen activators that generate plasmin in the vicinity of a thrombus to initiate thrombolysis, or in the pericellular region of cells to facilitate migration and/or tissue remodeling. It has been shown that the physiologically relevant form of PAI-1 is in a complex with the abundant plasma glyco-protein, vitronectin. The interaction between vitronectin and PAI-1 is important for stabilizing the inhibitor in a reactive conformation. Although the complex is clearly significant, information is vague regarding the composition of the complex and consequences of its formation on the distribution and activity of vitronectin in vivo. Most studies have assumed a 1:1 interaction between the two proteins, but this has not been demonstrated experimentally and is a matter of some controversy since more than one PAI-1-binding site has been proposed within the sequence of vitronectin. To address this issue, competition studies using monoclonal antibodies specific for separate epitopes confirmed that the two distinct PAI-1-binding sites present on vitronectin can be occupied simultaneously. Analytical ultracentrifugation was used also for a rigorous analysis of the composition and sizes of complexes formed from purified vitronectin and PAI-1. The predominant associating species observed was high in molecular weight (M(r) ~ 320,000), demonstrating that self-association of vitronectin occurs upon interaction with PAI-1. Moreover, the size of this higher order complex indicates that two molecules of PAI-1 bind per vitronectin molecule. Binding of PAI-1 to vitronectin and association into higher order complexes is proposed to facilitate interaction with macromolecules on surfaces

    Promoting the musical engagement of autistic children in the early years through a program of parental support: an ecological research study

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    Some autistic children display an intuitive capacity to reproduce and restyle the musical stimuli that they encounter in their environments. Music also offers a safe space for the development of social competencies and, across the spectrum, musical interventions are regarded as an effective way of promoting engagement with others. Yet, there is a lack of empirically researched music programs for parents and carers of children with autism. In this study, 11 families with autistic children incorporated music making into everyday life, supported by researcher-practitioners and framed by resources outlining musical activities based on the Sounds of Intent in the Early Years framework. Assessment of video data and interviews revealed that the new resources were flexible enough to be adapted to each child and they helped parents to build confidence to engage with their children musically. It was found that children had an increased interest and engagement in music as well as in joint play, which impacted positively on their musical and social development. The interpersonal music spaces created by the parents provided opportunities for unlocking expressiveness and interactive behavior, which in turn supported verbal development, emotional regulation and social interaction. These findings have implications for arts-in-health research and highlight the potentially crucial role of parents as mentors for their child’s musical development. The study further demonstrates that specialist musical training is not a requirement to develop parent–child engagement in music making at home

    Bilateral neonatal suppurative sialadenitis progressing to abscess formation in a preterm neonate

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    Aims: We report a case of bilateral neonatal suppurative sialadenitis (NSS) in an extremely low birth weight infant (ELBW). Methods: The infant developed bilateral sub-mandibular swelling at 3 weeks of age. NSS with abscess was confirmed with ultrasound. Despite intravenous antibiotic therapy the masses increased in size and developed abscesses. Results: Unilaterally the abscess discharged via Whartonâ s duct necessitating intubation to protect the airway. The abscess remnant was incised and drained. Culture grew a methicillin sensitive staphyloccocus aureus. The NSS resolved following two weeks of antibiotics. Conclusion: We wish to highlight the importance of early recognition of this rare condition in preterm neonates

    TeV physics and the Planck scale

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    Supersymmetry is one of the best motivated possibilities for new physics at the TeV scale. However, both concrete string constructions and phenomenological considerations suggest the possibility that the physics at the TeV scale could be more complicated than the Minimal Supersymmetric Standard Model (MSSM), e.g., due to extended gauge symmetries, new vector-like supermultiplets with non-standard SU(2)xU(1) assignments, and extended Higgs sectors. We briefly comment on some of these possibilities, and discuss in more detail the class of extensions of the MSSM involving an additional standard model singlet field. The latter provides a solution to the ÎĽ\mu problem, and allows significant modifications of the MSSM in the Higgs and neutralino sectors, with important consequences for collider physics, cold dark matter, and electroweak baryogenesis.Comment: 17 pages, 5 figures. To appear in New Journal of Physic

    Gamma Ray Lines from a Universal Extra Dimension

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    Indirect Dark Matter searches are based on the observation of secondary particles produced by the annihilation or decay of Dark Matter. Among them, gamma-rays are perhaps the most promising messengers, as they do not suffer deflection or absorption on Galactic scales, so their observation would directly reveal the position and the energy spectrum of the emitting source. Here, we study the detailed gamma-ray energy spectrum of Kaluza--Klein Dark Matter in a theory with 5 Universal Extra Dimensions. We focus in particular on the two body annihilation of Dark Matter particles into a photon and another particle, which produces monochromatic photons, resulting in a line in the energy spectrum of gamma rays. Previous calculations in the context of the five dimensional UED model have computed the line signal from annihilations into \gamma \gamma, but we extend these results to include \gamma Z and \gamma H final states. We find that these spectral lines are subdominant compared to the predicted \gamma \gamma signal, but they would be important as follow-up signals in the event of the observation of the \gamma \gamma line, in order to distinguish the 5d UED model from other theoretical scenarios.Comment: 21 pages, 6 figure
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