964 resultados para Aluminium base alloys
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Fly ash was used in this evaluation study to replace 30, 50 and 70 percent of the 400 1bs. of cement currently used in each cu. yd. of portland cement econocrete base paving mix. Two Class "c" ashes and one Class "F" ash from Iowa approved sources were examined in each mix. When Class "c" ashes were used, they were substituted on the basis of 1.0 pound for each pound of cement removed. When Class "F" ash was used, it was substituted on the basis of 1.25 pounds of ash for each pound of cement removed. Compressive strengths with and without fly ash were determined at 7, 28 and 56 days of age. In most cases, strengths were adequate. The freeze/thaw durability of the econocrete mixes studied was not adversely affected by the presence of fly ash. The tests along with erodibility and absorption tests have demonstrated the feasibility of producing econocrete with satisfactory mechanical properties even when relatively low quality and/or locally available aggregate is being used at no sacrifice to strength and/or durability.
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Evidence-based (EBP) aims for a new distribution of power centered on scientific evidence rather than clinical expertise. The present article describes the operational process of EBP by describing the implementation stages of this type of practise. This stage presentation is essential given that there are many conceptions end models of EBP and that some nurses have a limited knowledge of its rules ans implications. Given that number and formulation of the stages varies by author, the process presented here attempts to integrate the different stages reviewed.
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Geometric parameters of binary (1:1) PdZn and PtZn alloys with CuAu-L10 structure were calculated with a density functional method. Based on the total energies, the alloys are predicted to feature equal formation energies. Calculated surface energies of PdZn and PtZn alloys show that (111) and (100) surfaces exposing stoichiometric layers are more stable than (001) and (110) surfaces comprising alternating Pd (Pt) and Zn layers. The surface energy values of alloys lie between the surface energies of the individual components, but they differ from their composition weighted averages. Compared with the pure metals, the valence d-band widths and the Pd or Pt partial densities of states at the Fermi level are dramatically reduced in PdZn and PtZn alloys. The local valence d-band density of states of Pd and Pt in the alloys resemble that of metallic Cu, suggesting that a similar catalytic performance of these systems can be related to this similarity in the local electronic structures.
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Référence bibliographique : Weigert, 160
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Référence bibliographique : Weigert, 386
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Référence bibliographique : Weigert, 387
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Référence bibliographique : Weigert, 596
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Référence bibliographique : Weigert, n. d.
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Référence bibliographique : Weigert, 606
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L’aspiració de trobar una eina que pugui ajudar a identifi car els papers atenent les sevescaracterístiques sorgeix a fi nal segle XVIII amb les primeres descripcions de les filigranespapereres i va prenent cos al segle XIX com a ciència auxiliar de la codicologia.Des de les últimes dècades del segle XX, les filigranes han anat adquirint un interès creixententre els restauradors de document gràfi c —com una eina més per a la presa de decisions i pera la valoració del procés de restauració— i entre els documentalistes, historiadors, museòlegsi bibliòfils —per a la datació i autenticació de les obres— i, fins i tot, en investigacionspolicials i jurídiques per aclarir algun fet delictiu. No obstant això, durant aquests 150 anys, l’estudi del paper a través de les filigranes papereres a Espanya no ha experimentat cap avenç significatiu pel que fa als mètodes i procediments seguits per a l’obtenció i gestió deles dades. En l’àmbit europeu, encara que a partir dels anys 90 sorgeixen noves propostesd’estudi, aquestes limiten la investigació a l’anàlisi de la filigrana sense assolir una visió global del plec sortit de la forma.
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Es presenta el servei de sumaris de la Biblioteca de la Universitat de Barcelona. Els usuaris del servei poden consultar, a través de la web de la biblioteca, els sumaris de les revistes subscrites i rebre els que desitgin per correu electrònic. El servei permet racionalitzar la inversió en subscripcions i mantenir l¿usuari puntualment informat.
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Base de dados que objetiva disponibilizar, em único local de fácil e rápido acesso, informações básicas essenciais aos interessados na biblioteca do futuro, seja ela eletrônica, virtual, digital, sem paredes ou biônica. Desenvolvida com o software MicroIsis, encontra-se disponível na Internet a todo e qualquer interessado por intermédio do servidor de bases de dados ISIS para o WWW (software intitulado WWWIsis, desenvolvido pela Bireme). A recuperação da informação é possível por índice de termos indexados ou formulário de pesquisa utilizando-se lógica booleana em campos de autoria, título, assunto, data e língua. Delimitações de pesquisa por tipo de documento e conteúdo de informação também são oferecidas. URL: http://www.eca.usp.br/eca/nucleos/biblial/futura/index.htm
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Descreve o processo de seleção de revistas científicas adotado pelo Institute for Scientific Information (ISI) para incorporar publicações em sua base de dados, abordando critérios como periodicidade, conteúdo editorial, internacionalidade e análise de citação.