7,873 research outputs found

    A study of solid-propellant vaporization and diffusion processes Final technical report

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    Vaporization rate and diffusion coefficient determined for organic additives to polyurethane solid propellants - dioctyl adipate and ferrocen

    Dental anomalies in Chinese children with cleft lip and palate

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    NERVA irradiation program, GTR test 21. Volume 4 - Effect of radiation on structural materials tested at cryogenic and elevated temperatures

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    Effect of radiation on structural materials for NERVA engine tested at cryogenic and elevated temperatures - Vol.

    Ab initio diffusional potential energy surface for CO chemisorption on Pd{110} at high coverage: Coupled translation and rotation

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    [[abstract]]The ground statepotential energy surface for CO chemisorption across Pd{110} has been calculated using density functional theory with gradient corrections at monolayer coverage. The most stable site corresponds well with the experimental adsorption heat, and it is found that the strength of binding to sites is in the following order: pseudo-short-bridge>atop>long-bridge>hollow. Pathways and transition states for CO surfacediffusion, involving a correlation between translation and orientation, are proposed and discussed.[[notice]]補正完畢[[journaltype]]國外[[booktype]]紙本[[countrycodes]]US

    Porous PDMS force sensitive resistors

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    Here we present an elastomeric force sensitive resistor (FSR) made from a porous matrix of polydimethylsiloxane (PDMS) filled with carbon black. The fabrication process is based on the use of a low cost sacrificial sugar cube scaffold which leads to a highly porous and compressible material. By filling this porous matrix with carbon black we can achieve typical resistance changes from 20 kW to 100 W for an applied 95% compressive strain. This material is suitable for a wide variety of sensing applications which include tactile artificial skin for robotics and solvent detection

    Scars of intense accretion episodes at metal-rich white dwarfs

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    A re-evaluation of time-averaged accretion rates at DBZ-type white dwarfs points to historical, time-averaged rates significantly higher than the currently observed episodes at their DAZ counterparts. The difference between the ongoing, instantaneous accretion rates witnessed at DAZ white dwarfs, which often exceed 10 8gs -1, and those inferred over the past 10 5-10 6yr for the DBZ stars can be of a few orders of magnitude, and therefore must result from high-rate episodes of tens to hundreds of years so that they remain undetected to date. This paper explores the likelihood that such brief, intense accretion episodes of gas-phase material can account for existing data. For reasonable assumptions about the circumstellar gas, accretion rates approaching or exceeding 10 15gs -1 are possible, similar to rates observed in quiescent cataclysmic variables, and potentially detectable with future X-ray missions or wide-field monitoring facilities. Gaseous debris that is prone to such rapid accretion may be abundant immediately following a tidal disruption event via collisions and sublimation, or if additional bodies impinge upon an extant disc. Particulate disc matter accretes at or near the Poynting-Robertson drag rate for long periods between gas-producing events, consistent with rates inferred for dusty DAZ white dwarfs. In this picture, warm DAZ stars without infrared excesses have rates consistent with accretion from particulate discs that remain undetected. This overall picture has implications for quasi-steady state models of accretion and the derived chemical composition of asteroidal debris in DBZ white dwarfs

    The scaling of X-ray variability with luminosity in Ultra-luminous X-ray sources

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    We investigated the relationship between the X-ray variability amplitude and X-ray luminosity for a sample of 14 bright Ultra-luminous X-ray sources (ULXs) with XMM-Newton/EPIC data, and compare it with the well established similar relationship for Active Galactic Nuclei (AGN). We computed the normalised excess variance in the 2-10 keV light curves of these objects and their 2-10 keV band intrinsic luminosity. We also determined model "variability-luminosity" relationships for AGN, under several assumptions regarding their power-spectral shape. We compared these model predictions at low luminosities with the ULX data. The variability amplitude of the ULXs is significantly smaller than that expected from a simple extrapolation of the AGN "variability-luminosity" relationship at low luminosities. We also find evidence for an anti-correlation between the variability amplitude and L(2-10 keV) for ULXs. The shape of this relationship is consistent with the AGN data but only if the ULXs data are shifted by four orders of magnitudes in luminosity. Most (but not all) of the ULXs could be "scaled-down" version of AGN if we assume that: i) their black hole mass and accretion rate are of the order of ~(2.5-30)x 10E+03 Msolar and ~ 1-80 % of the Eddington limit, and ii) their Power Spectral Density has a doubly broken power-law shape. This PDS shape and accretion rate is consistent with Galactic black hole systems operating in their so-called "low-hard" and "very-high" states.Comment: 10 pages, 5 figures, 2 tables, accepted for publication in A&

    Constrained analytical interrelations in neutrino mixing

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    Hermitian squared mass matrices of charged leptons and light neutrinos in the flavor basis are studied under general additive lowest order perturbations away from the tribimaximal (TBM) limit in which a weak basis with mass diagonal charged leptons is chosen. Simple analytical expressions are found for the three measurable TBM-deviants in terms of perturbation parameters appearing in the neutrino and charged lepton eigenstates in the flavor basis. Taking unnatural cancellations to be absent and charged lepton perturbation parameters to be small, interrelations are derived among masses, mixing angles and the amount of CP-violation.Comment: To be published in the Springer Proceedings in the Physics Series under the heading of the XXI DAE-BRNS Symposium (Guwahati, India

    Evaluation of the Effectiveness of Disseminating Workplace Health Promotion Resources to Businesses

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    Encouraging workplaces to undertake health promotion is important yet little is known of the types of information small and medium size workplaces would find useful. Two resources on workplace health promotion were mailed to 213 workplaces. The resources provided information on the benefits of workplace health promotion, suggestions for low-cost activities and components of a sustainable program. 62% of respondents rated the resources as either ‘very useful’ or ‘somewhat useful’. Workplaces in ‘contemplation’ and ‘preparation’ stages of change for engaging in WHP were most likely to have undertaken an activity to support the health and well-being of employees or be intending to, as a result of reading the resources .The findings of this study provide useful information on the reach and impact of dissemination of health promotion resources by mail to workplaces, and particularly small businesses

    Seré un emblema

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    El acto teatral feudo del imperio de lo efímero pretende lacaptación o reproducción de lo real a través de la manifestaciónde lo vivo en el plano de la ficción. El despertarde las memorias, la sensibilización de los sentidos, elincremento de las capacidades de concentración, deadaptación, de imaginación son objetivos y contenidosque subyacen en los distintos métodos de formación deactores.En este trabajo se realizará una mirada crítica y un breveanálisis sobre técnicas de formación y entrenamiento deactores
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