Relativistic Archimedes law for fast moving bodies and the general-relativistic resolution of the submarine paradox

We investigate and solve in the context of general relativity the apparent paradox which appears when bodies floating in a background fluid are set in relativistic motion. Suppose some macroscopic body, say, a submarine designed to lie just in equilibrium when it rests (totally) immersed in a certain background fluid. The puzzle arises when different observers are asked to describe what is expected to happen when the submarine is given some high velocity parallel to the direction of the fluid surface. on the one hand, according to observers at rest with the fluid, the submarine would contract and, thus, sink as a consequence of the density increase. on the other hand, mariners at rest with the submarine using an analogous reasoning for the fluid elements would reach the opposite conclusion. The general relativistic extension of the Archimedes law for moving bodies shows that the submarine sinks. As an extra bonus, this problem suggests a new gedankenexperiment for the generalized second law of thermodynamics.

Platinum Group Minerals in Eastern Brazil GEOLOGY AND OCCURRENCES IN CHROMITITE AND PLACERS

Brazil does not have working platinum mines, nor even large reserves of the platinum metals, but there is platinum in Brazil. In this paper, four massifs (mafic/ultramafic complexes) in eastern Brazil, in the states of Minas Gerais and Ceara, where platinum is found will be described. Three of these massifs contain concentrations of platinum group minerals or platinum group elements, and gold, associated with the chromitite rock found there. In the fourth massif, in Minas Gerais State, the platinum group elements are found in alluvial deposits at the Bom Sucesso occurrence. This placer is currently being studied.

Estudo da porção offshore da bacia do Benin e o seu potencial no armazenamento de hidrocarbonetos, margem equatorial africana

Pós-graduação em Geologia Regional - IGCE

Mapeamento da ilha da Trindade, Atlântico Sul

The area chosen for this study is the island of Trinidade, which is located 1167 km off the Brazilian coast, in parallel Victory at 20 ° 30'S and 29 º 19'W, being the most easterly point of our continent. The isolation of oceanic island of Trinidade leaves no noticeable that she is part of a large submarine volcanic chain oriented east-west lineament known as Vitória- Trindade. Along with the island of Martin Vaz, who is Federal Territory is administered by the Navy of Brazil. Both correspond to Source alkaline volcanic islands. The area of the island of Trinidad has approximately 10 km2. Geologically consisting ankaratritic spills, spills tannbuschiticos, volcanic tuff spills analcite-ankaratrite, phonolite spills, spills nefelinite, pyroclastics, spills grazinite, tinguaitos, olivine-analcitito, calcarenite dunes and wind according to Almeida (1961). The island has its base on the ocean floor, at 5,800 m depth. It is the only place still recognizes preserved volcanic necks and plugs, as well as remnants of a volcano in Brazil. Magmatism occurred here a sodium alkali-silica subsaturated where his wrist was last 50,000 years according to Almeida (1961). It is a place with restricted access due to their distance from the coast, his contribution and hard to be an exclusive area of the Navy. On the island with peaks occur up to 620 meters high, and its rugged mountainous terrain and difficult access to very specific points, as the peak of Desire, peak Fazendinha, Monument and other points on the island. Because of its location far from the coast, its small infrastructure, difficulty of landing and restricted access by sea, the island of Trinidad offers no possibility of tourism, being a military outpost, and scientific basis of great importance, which conduct research in area of marine biology, oceanography, geology and others