998 resultados para Aço ASTM A515 Gr 60
Resumo:
Entre fines de la década del '50 y principios de la década siguiente, numerosas publicaciones literarias, culturales y políticas surgieron en la Argentina. Estas revistas fueron promovidas principalmente por una generación naciente que, luego del derrocamiento del segundo gobierno del General Perón, modificaría su interpretación de la realidad Argentina en general y del peronismo en particular mostrando su visión, en muchos casos, a través de las páginas de esas publicaciones. El presente trabajo va a hacer foco en Contorno, Situación y Pasado y Presente, tres revistas político-culturales realizadas principalmente por grupos de jóvenes intelectuales de izquierda en las décadas del ?50 y ?60. Estos grupos promovían posturas críticas y de ruptura con las tradiciones e ideas de sus círculos o partidos de orígenes. El objetivo que se persigue en el análisis de esas revistas es intentar explicar la búsqueda de unidad entre esas juventudes de izquierda y los sectores trabajadores que, en su gran mayoría, se reconocían como peronistas; identificando en esa indagación los principales actores, sus prácticas y formas discursivas, los conflictos y tensiones generados al interior de sus grupos de referencia o partidos de origen y las influencias que motivaban el accionar. Para ello se utilizará, además de las nombradas revistas, bibliografía sobre el período, diarios y fuentes documentales de la época
Resumo:
Fil: Sujatt, Julio Andrés. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.
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Este artículo busca describir y analizar las acciones y reacciones que generó sobre el discurso y práctica del actor social cooperativo, la crisis del cultivo algodonero durante los años '60 en la Argentina. Se toma el caso de la Cooperativa Agrícola Algodonera La Banda Limitada (CAALBA) de Santiago del Estero. Asociación de pequeños productores inserta en un entramado de relaciones con instituciones de la sociedad civil y el Estado que -en términos gramscianos- fueron compartimentos con interacción en el marco de las disputas hegemónicas sobre el proyecto de desarrollo social. Se presentan también a lo largo del trabajo a la CAALBA ante estos nuevos escenarios, así como fue la Corporación del Río Dulce
Resumo:
Pliocene and Pleistocene volcanic glass fragments from Mariana Trough sediments at Sites 453 (16 samples) and 454 (4 samples), located near the western edge of the trough and just west of the spreading axis, respectively, have been analyzed for major elements with an electron microprobe. They derive from volcanic activity on the present Mariana active arc. The glasses from Site 453 are all tholeiitic with a wide range of SiO2 contents. Those less than 2 m.y. old have slightly lower TiO2 and higher K2O contents than the older ones. The glasses from Site 454 are all Pleistocene and resemble the younger glasses at Site 453. Major element compositions of the older basaltic glasses at Site 453 are similar to those of the Mariana Trough basalts drilled on Leg 60. Both older and younger suites of glasses differ from the composition of rocks exposed on the active arc, which are assumed to be younger than any of the samples studied (i.e., about 200,000 y.). A third suite is represented by the arc rocks exposed on the volcanic islands. These have a smaller range of SiO2 contents and contain more A12O3 but less K2O, TiO2, and FeO1 (total Fe as FeO) than the sediment glasses studied. Further, a plot of FeO1 against MgO for the arc rocks does not follow the island arc tholeiite trend of the trough sediment glasses. Using the major element compositions of the arc rocks and sediment glasses, we can recognize three phases of volcanic activity, as indicated. The first evidence of the oldest phase of activity occurs 5 Ma, about 4.5 m.y. after the trough started to form. The second commenced about 2 Ma, and the last, including present-day activity, began within the last 200,000 y. Initially the rocks had major element affinities with the tholeiitic Mariana Trough seafloor, but this influence declined as the trough widened.
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Basalts in two holes spaced 200 meters apart at DSDP Site 456 in the Mariana Trough both show a downward sequence of nonoxidative and oxidative zones of alteration, each 10 to 15 meters thick, overlying fresh basalts. Basalts in the nonoxidative zone have been extensively chloritized and have vein and vesicle fillings of quartz, opal, chlorite, calcite, and pyrite. Minor sulfides are chalcopyrite and digenite. Basalts in the oxidative zone have abundant smectites and iron hydroxides and are variably enriched in K, Rb, and Ba, unlike the nonoxidative basalts above them. We propose that the oxidative zone was a zone of mixing between high-temperature, reduced hydrothermal fluids moving horizontally beneath impermeable sediments at the top of the pillowed basement lavas and cold, oxygenated seawater in interpillow voids deeper in the basement. Recrystallized vitric tuffs immediately above the basalts containing authigenic quartz and wairakite, as well as occurrence of chlorite, epidote, and chalcopyrite in the basalts, suggest temperatures of alteration in excess of 200°C.
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Neogene stratigraphy of the tropical and subtropical Pacific on radiolaria is studied in the book. A detailed comparison of coeval systems from tropics and subtropics is given. A possibility of use of a uniform zonal scale in these areas is proved. Magnitude of changes of complexes on borders of Neogene zones is studied in detail. Six stages in development of radiolarians are identified in the tropics in Neogene. Stratigraphic levels, where the greatest changes of fauna occurred, are natural boundaries of these stages. 72 species of radiolarians (two of which are new) are described in the book.