No description available.

No description available.

The Indo-Australian Plate is actively deforming at its margins and within its interior. In south-central Australia, more than 3000 km from the closest active plate boundary, a geomorphically rugged and apparently youthful mountain range has developed, rising up to 1.1km above the adjacent flat-lying outback plains. These ‘Flinders’ and ‘Barrier’ Ranges are seismically active and bound by major reverse fault scarps with clear evidence for Plio-Quaternary displacements, implying that young and active intraplate tectonism has played a fundamental role in their development. Palaeoseismic investigations and optically stimulated luminescence (OSL) chronology indicate faulting occurred in response to a series of large magnitude (~M6.6 to M7.3) palaeo-earthquakes with recurrence intervals of ~1:20,000 to~1:80,000 yrs and long-term fault slip rates of ~50 m Myr-1. Geomorphic observations and 10Becosmogenic nuclide dating indicate surprisingly high and spatially variable rates of bedrock erosion from fault-affected catchments in the Flinders Ranges. Slowly eroding bedrock summit surfaces have been uplifted up to 12 m in the last 60,000-100,000 years relative to more rapidly eroding valley floors and bounding piedmonts, indicating Late Quaternary increases in elevation and relief in response to intraplate tectonism and erosion. However, both facies changes and sediment aggradation-dissection cycles in alluvial fan sequences are out-of-synch within dividual tectonic events, indicating that an aspect of climate (aridification, changing flood frequency-magnitude distributions) has governed the spatial-temporal distribution of range front sedimentation.

Thesis (Ph. D.)--University of Texas at Austin, 2007. Thesis (Ph. D.)--Université Paul Sabatier, 2007. / Thesis completed in partial fulfillment of the requirements for a joint Ph. D. from the University of Texas at Austin and the Université Paul Sabatier. Vita. Includes bibliographical references.

Thesis (Ph.D.)--McMaster University (Canada), 1992. / Source: Dissertation Abstracts International, Volume: 54-08, Section: B, page: 4217. Adviser: J. S. Chang.

Thesis (Ph.D.)--University of Melbourne, School of Earth Sciences, 2007. / Typescript. Includes bibliographical references (leaves 211-240).

Techn. Hochsch., Diss., 1999--Aachen.

Freie Universiẗat, Diss., 2000--Berlin. / Dateiformat: zip, Dateien im PDF-Format.

Universiẗat, Diss., 2003--Stuttgart.

Made available in DSpace on 2014-06-11T19:27:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-02-01Bitstream added on 2014-06-13T19:35:06Z : No. of bitstreams: 1 moreira_af_me_ilha.pdf: 2273819 bytes, checksum: 1e78bc9d82277d9e226607de07b8a4a9 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho é verificar a influência da atmosfera protetora nas características geométricas do cordão de solda, na susceptibilidade a formação de porosidades e inclusões, na microestrutura, na dureza e nas taxas de deposição e diluição do metal de solda obtido através das soldagens GMAW e FCAW, com arame sólido AWS E70S-6 e tubular AWS E309LT-1, respectivamente, visando otimizar o processo de recuperação por soldagem de turbinas Francis de aço carbono danificadas por erosão cavitacional. Para tanto, foram feitas deposições “bead on plate” com arames de 1,2 mm de diâmetro sobre chapas de aço carbono ASTM A-36. Utilizou-se como gás de proteção: Argônio puro, CO2 puro, misturas binárias Argônio/CO2, Argônio/O2 e uma mistura ternária Argônio/CO2/O2. No caso da soldagem FCAW, a taxa de deposição parece não ter estrita relação com o tipo de gás empregado, parecendo ser mais dependente da corrente de soldagem. Já parâmetros como largura, altura, penetração, taxa de diluição, nível de porosidades/inclusões e fração de ferrita parecem sofrer influência direta da composição química do gás de proteção empregado. No caso da soldagem GMAW, a taxa de deposição, largura, altura, penetração, taxa de diluição e nível de porosidades/inclusões demonstraram estar diretamente relacionados ao tipo de gás de proteção empregado. Não foi observada uma significativa variação nos valores de dureza do metal de solda obtidos com o processo FCAW devido a mudança na composição química do gás de proteção. Já os picos de dureza encontrados na ZTA para esse processo podem ser decorrentes da formação de carbonetos de cromo. No caso da soldagem GMAW, o que se pode observar foi uma queda na dureza desde o metal de solda até o metal de base. Os elevados valores de dureza do metal de solda para esse tipo de soldagem... / The goal of this study is to verify the influence of shielding gas composition in the geometric aspects of weld metals like width, height and depth, besides dilution and deposition rates. Besides this analyses were made upon the volumetric fraction of porosities/inclusions and upon the ferrite fraction to the austenitic weld metal. Additionally was withdrawn microhardness Vickers profiles from weld metal up base metal. Weld metals have been made with “bead on plate” deposition of wires AWS E309LT-1 and AWS E70S-6, both with 1,2 mm diameter, upon carbon steel ASTM A-36 plates by FCAW and GMAW welding process, respectively. The shielding gases employed were: pure Argon, pure CO2, binary mixtures of Argon/CO2, Argon/O2 and shielding gas containing Argon/CO2/O2. Related to the FCAW process, the deposition rate didn’t show a direct relationship with the chemical composition of shielding gas, being more dependent of the welding current. Parameters like width, height, depth, dilution rate, porosity/inclusion levels and ferrite fraction showed to keep a direct relation to the chemical composition of the shielding gas. To the GMAW process, deposition rate, width, height, depth, dilution ratio and porosity/inclusion levels maintained a direct relation to the chemical composition of shielding gas. It wasn’t observed a significative variation upon microhardness values of the weld metals produced with FCAW process because of the change in the shielding gas employed. In the GMAW welding, it was observed an abatement on the microhardness profile from the weld metal upto the base metal because, of, probably, the quenching increase in this area by the dilution of a metal with a high quantity of Manganese manganese coming from wire composition.