988 resultados para Manganese.
Resumo:
The cores and dredges described in this report were taken on the KH-69-2 Expedition in April-June, 1969 by the Ocean Research Institute, University of Tokyo from the Hakuho Maru. A total of 12 cores and dredges sites have been recovered.
Resumo:
Mineralogical and chemical analyses performed on 67 ferromanganese nodules from widely varying locations and depths within the marine environment of the Pacific Ocean indicate that the minor element composition is controlled by the mineralogy and that the formation of the mineral phases is depth dependent. The pressure effect upon the thermodynamics or kinetics of mineral formation is suggested as the governing agent in the depth dependence of the mineralogy. The minor elements, Pb and Co, appear concentrated in the dMnO2 phase, whereas Cu and Ni are more or less excluded from this phase. In the manganites, Pb and Co are relatively low in concentration, whereas Cu and Ni are spread over a wide range of values. The oxidation of Pb and Co from divalent forms in sea water to higher states can explain their concentration in the dMnO2 phase.
Resumo:
Although various models have been proposed to explain the origin of manganese nodules (see Goldberg and Arrhenius), two major hypotheses have received extensive attention. One concept suggests that manganese nodules form as the result of interaction between submarine volcanic products and sea water. The common association of manganese nodules with volcanic materials constitutes the main evidence for this theory. The second theory involves a direct inorganic precipitation of manganese from sea water. Goldberg and Arrhenius view this process as the oxidation of divalent manganese to tetravalent manganese by oxygen under the catalytic action of particulate iron hydroxides. Manganese accumulation by the Goldberg and Arrhenius theory would be a relatively slow and comparatively steady process, whereas Bonatti and Nayudu believe manganese nodule formation takes place subsequent to the eruption of submarine volcanoes by the acidic leaching of lava.
Resumo:
Cruise Mn-74-02 of the R/V MOANA WAVE was the second part of the field work of the NSF/IDOE Inter-University Ferromanganese Research Program in 1974, and we gratefully acknowledge the support of the office for the International Decade of Ocean Exploration and the Office of Oceanographic Facilities and Support. This program was designed to investigate the origin, growth, and distribution of copper/nickel-rich manganese nodules in the Pacific Ocean. The field effort was designed to satisfy sample requirements of the fifteen principal investigators, while increasing general knowledge of the copper/nickel-rich nodule deposits of the equatorial Pacific. This report is the second of a series of cruise reports designed to assist sample requests for documented nodules, sediment, and water samples so that laboratory results can be realistically compared and related to the environment of nodule growth. Nodule samples and bathymetric and navigational data are archived at the Hawaii Institute of Geophysics, University of Hawaii. Bulk chemical analyses of nodules and reduction of survey data were carried out at Hawaii. Sediment cores were stored at the University of Hawaii and at Scripps Institution of Oceanography. The SIO analytical facility provided stratigraphic data on sediment chemistry.
Resumo:
The cores and dredges described are taken during the R/V New Horizon RISE III Expedition from April until May 1979 by the Scripps Institute of Oceanography. A total of 36 cores and dredges were recovered and are available at Scripps Institute of Oceanography for sampling and study. The goal of this expedition was to accomplish the field work of a combined field and laboratory study aimed at increasing the understanding of the origins and development of young oceanic volcanoes.
Resumo:
Copper-manganese spinel containing anodes were synthesized by a facile sol-gel method and evaluated in lithium-ion battery applications for the first time. The synergistic effects between copper-manganese and the aqueous binder (sodium carboxymethyl cellulose) provided a high specific capacity and excellent cycling performance. It was found that the specific capacity of the copper-manganese spinel remained at 608 mAh g−1 after 100 cycles at a current density of 200 mA g−1. Furthermore, a relatively high reversible capacity of 278 mAh g−1 could be obtained at a current density of 2000 mA g−1, indicating a good rate capability. These studies suggest that copper-manganese spinel is a promising material for lithium-ion battery applications due to a combination of good electrochemical performance and low cost.