37,401 research outputs found

    Serving Immigrants: An Old but Still Relevant Jesuit Tradition

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    Adsorption Behaviour of [(4-Hydroxy-6-methyl-2-oxo-2Hpyran- 3-yl)-(4-methoxy-phenyl)-1methyl]-urea on Stainless Steel in Phosphoric Media

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    The adsorption of [(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-(4-methoxy-phenyl)- methyl]-urea on iron in phosphoric media was studied by using electrochemical technique. The adsorption mechanism was investigated using adsorption isotherms. The experimental data fit localized adsorption models. The values for free energy of adsorption, o DGads , were also calculated at each surface coverage, �, of the studied compound by applying the mathematical model of Bockris – Swinkels adsorption isotherm. The variation of free energy of adsorption o ads DG with surface coverage, �, was interpreted in terms of deviation from ideal condition assumed in Langmuir model. A possible adsorption model of HPU2 molecules on to the metal surface was suggested

    Catalyzing Collaboration: The Developing Infrastructure for Federal Public Private Partnerships

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    There is growing interest on the part of government, philanthropy and business to work together to achieve greater impact. Partnerships that span the sectors have the potential to achieve more than any sector can achieve on its own by leveraging the strengths of each. However, such partnerships also give rise to added costs and entail greater risks. To address these challenges, offices of strategic partnerships are emerging at the federal level to provide an infrastructure to catalyze cross-sectoral partnerships. This report examines 21 such offices in federal departments and agencies whose purpose is to facilitate and accelerate partnerships with philanthropy and business -- ranging from the Department of Housing and Urban Development and the Department of Education, to the Department of State and the Agency for International Development, to the Department of Homeland Security and the Federal Emergency Management Agency. The formation of these offices has been driven by champions within government -- many with prior experience in philanthropy or business -- that have witnessed the power of working collaboratively with other sectors. Their actions have often been reinforced by executive orders and other directives conducive to their growth. In the case of those offices that have been created in the last few years, they have also been encouraged by the examples of their more established counterparts

    Technologies for aerobraking

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    Aerobraking is one of the largest contributors to making both lunar and Mars missions affordable. The use of aerobraking/aeroassist over all propulsive approaches saves as much as 60 percent of the initial mass required in low earth orbit (LEO); thus, the number and size of earth to orbit launch vehicles is reduced. Lunar transfer vehicles (LTV), which will be used to transport personnel and materials from LEO to lunar outpost, will aerobrake into earth's atmosphere at approximately 11 km/sec on return from the lunar surface. Current plans for both manned and robotic missions to Mars use aerocapture during arrival at Mars and at return to Earth. At Mars, the entry velocities will range from about 6 to 9.5 km/sec, and at Earth the return velocity will be about 12.5 to 14 km/sec. These entry velocities depend on trajectories, flight dates, and mission scenarios and bound the range of velocities required for the current studies. In order to successfully design aerobrakes to withstand the aerodynamic forces and heating associated with these entry velocities, as well as to make them efficient, several critical technologies must be developed. These are vehicle concepts and configurations, aerothermodynamics, thermal protection system materials, and guidance, navigation, and control systems. The status of each of these technologies are described, and what must be accomplished in each area to meet the requirements of the Space Exploration Initiative is outlined

    Objective Bayes testing of Poisson versus inflated Poisson models

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    The Poisson distribution is often used as a standard model for count data. Quite often, however, such data sets are not well fit by a Poisson model because they have more zeros than are compatible with this model. For these situations, a zero-inflated Poisson (ZIP) distribution is often proposed. This article addresses testing a Poisson versus a ZIP model, using Bayesian methodology based on suitable objective priors. Specific choices of objective priors are justified and their properties investigated. The methodology is extended to include covariates in regression models. Several applications are given.Comment: Published in at http://dx.doi.org/10.1214/074921708000000093 the IMS Collections (http://www.imstat.org/publications/imscollections.htm) by the Institute of Mathematical Statistics (http://www.imstat.org
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