297 research outputs found

    Formation of ions and radicals from icy grains in comets

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    Ion and radical formation in comets are thought to occur primarily by photodissociation of gas phase molecules. Experimental evidence and theoretical calculations are presented that show that some of the radical and ions can come directly from ice grains. The experimental evidence suggest that if the frozen molecules on the surface of grains undergo direct dissociation then they may be able to release radicals directly in the gas phase. If the molecules undergo predissociation it is unlikely that they will release radicals in the gas phase since they should be quenched. Calculations of this direct photodissociation mechanism further indicate that even if the parent molecule undergoes direct dissociation, the yield will not be high enough to explain the rays structure in comets unless the radicals are stored in the grains and then released when the grain evaporates. Calculations were also performed to determine the maximum number of ions that can be stored in an icy grain's radius. This number is compared with the ratio of the ion to neutral molecular density. The comparison suggests that some of the ions observed near the nucleus of the comet could have originally been present in the cometary nucleus. It is also pointed out that the presence of these ions in icy grains could lead to radical formation via electron recombination. Finally, an avalanche process was evaluated as another means of producing ions in comets

    Replacement Namings in Sweden and America

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    Whatever Happened to the Old Buffalo Hunter?

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    Longevity and Mortality Among My Swedish Ancestors

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    Memory and meaning in architecture : Explain Explore Experience

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    Buildings designed today should have memory and meaning latent in their form. The site should instruct and direct the architecture that will be placed on it. Architect Tadao Ando states: The purpose of architecture is basically the construction of place (Frampton, 133). This basic principle of architecture is lost if architects fail to consider the region, the culture of the building\u27s users, the communities within which the building exists, the site on which it is built, or the expression the building creates. Architecture is not just the making of a building; it is the analysis of the site and the understanding of what is needed on the site. In order to make meaningful architecture we must address the site at three levels: the physical place, the cultural place, and the spiritual place. This thesis explains how architecture links memory and meaning through a reinterpretation of the regional climate, cultural heritage, and the multitude of physical and conceptual aspects that constitute site conditions

    Should The Stars In Your Service Flag Turn To Gold

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    https://digitalcommons.library.umaine.edu/mmb-vp/5519/thumbnail.jp

    The elements of economic development

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    More communities have come to realize that change is inevitable and they are establishing economic development programs to help them manage that change. At a time when the industrial revolution has given way to the information age, a good economic development program will help a community remain "tuned in" to the world. It can help business and industry to be more productive and also contribute to the community's overall viability. Accomplishing this takes a program that is broad-based and long-term.New 6/92/5M
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