Sulphidizing reactions in the flotation of oxidized copper minerals,II. Role of the adsorption and oxidation of sodium sulphide in the flotation of chrysocolla and malachite     

Sergio Castro  Heriban Soto  Jorge Goldfarb  Janusz Laskowski 《International Journal of Mineral Processing》1974,1(2):151-161

The rate of consumption of sulphide in the sulphidizing reactions of malachite and chrysocolla has been measured. The oxidation of sulphide ions at the surface of sulphidized chrysocolla was shown to take place. The influence of thiosulphate anions on the xanthate flotation of sulphidized malachite and chrysocolla was investigated and it was shown to depress the flotation of chrysocolla strongly.The result suggest, that the presence of thiosulphate as a product of simultaneous oxidation can be one of the reasons for the more difficult flotation of sulphidized chrysocolla.  相似文献   

Some aspects of the seismic hazard in Panama City     

Aristoteles Vergara Muñoz 《Natural Hazards》1990,3(3):233-248

The definition of earthquake sources in the Panama region on the basis of both tectonics and average seismicity rates, have recently led to the concept of a microplate surrounded by seismically active areas. The effects of these earthquakes on the place where the most important concentration of investments and population is located, the capital city of Panama, are analyzed in this paper using statistical approaches.The parameters of Gumbel's Type-I distribution of extreme values for a continuous interval of 60 yr annual maximum magnitudes were used to make probabilistic estimations of the seismic hazard in Panama City. An earthquake with magnitude 7.5 is capable of producing a modified Mercalli intensity VII in Panama City, provided the source distance is of the order of 100 km. This earthquake has a probability of occurrence of 69% in 50 yr.  相似文献   

Usefulness of microsatellite markers developed from Pagellus bogaraveo to genetically study five different species of Sparidae     

Jorge A. Piñera  David Bernardo  Gloria Blanco  Emilia Vázquez  & José A. Sánchez 《Marine Ecology》2007,28(S1):184-187

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Species and size selectivity in a Portuguese multispecies artisanal long-line fishery   总被引：1，自引：0，他引：1  

Erzini  Karim; Goncalves  Jorge M. S.; Bentes  Luis; Lino  Pedro G.; Cruz  Joao 《ICES Journal of Marine Science》1996,53(5):811-819

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Feeding ecology of cod (Gadus morhua L.) in Balsfjord and Ullsfjord, northern Norway, 1982-1983     

Santos  Jorge dos; Falk-Petersen  Stig 《ICES Journal of Marine Science》1989,45(2):190-199

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The simultaneous analysis of total nitrogen and total phosphorus in natural waters   总被引：1，自引：0，他引：1  

Jorge C. Valderrama 《Marine Chemistry》1981,10(2):109-122

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Continuation of normal doubly symmetric orbits in conservative reversible systems   总被引：1，自引：1，他引：0  

Francisco Javier Muñoz-Almaraz  Emilio Freire  Jorge Galan-Vioque  Andre Vanderbauwhede 《Celestial Mechanics and Dynamical Astronomy》2007,97(1):17-47

In this paper we introduce the concept of a quasi-submersive mapping between two finite-dimensional spaces, we obtain the main properties of such mappings, and we introduce “normality conditions” under which a particular class of so-called “constrained mappings” are quasi-submersive at their zeros. Our main application is concerned with the continuation properties of normal doubly symmetric orbits in time-reversible systems with one or more first integrals. As examples we study the continuation of the figure-eight and the supereight choreographies in the N-body problem.  相似文献   

A comparison of the Iberian and Ebro Basins during the Permian and Triassic, eastern Spain: A quantitative subsidence modelling approach   总被引：2，自引：0，他引：2  

Henar Vargas  Jorge M. Gaspar-Escribano  Jos Lpez-Gmez  Jan-Diederik Van Wees  Sierd Cloetingh  Raúl de La Horra  Alfredo Arche 《Tectonophysics》2009,474(1-2):160

The Permian–Triassic sediments of the Iberian Plate are a well studied case of classical Buntsandstein–Muschelkalk–Keuper facies, with good sedimentological interpretations and precise datings based on pollen and spore assemblages, ammonoids and foraminifera. Synrift–postrift cycles are recorded in these facies, but there are only a few studies of quantitative subsidence analysis (backstripping method) and only a previous one using forward modelling for the quantification of synrift–postrift phases of this period.Here we present the results obtained by the quantitative analysis of fourteen field sections and oil-well electric log records in the Iberian and Ebro Basins, Spain. Backstripping analysis showed five synrift phases of 1 to 3 million years duration followed by postrift periods for the Permian–Triassic interval. The duration, however, shows lateral variations and some of them are absent in the Ebro Basin. The forward modelling analysis, assuming local isostatic compensation, has been applied to each observation point using one-layer and two-layer lithospheric configurations. The second one shows a better fit between observation and model prediction in a systematic way, so a two layer configuration is assumed for the sedimentary basin filling analysis. Lithospheric stretching factors β and δ obtained in the forward modelling analysis are never higher than 1.2, but sometimes β < 1 and simultaneously δ > 1 in the same section. If surficial extension is compensated by deep compression either at the roots of the rift basins or in far-away zones is not yet clear, but this anomaly can be explained using a simple shear extensional model for the Iberian and Ebro basins.  相似文献   

Consolidation around stone columns. Influence of column deformation   总被引：2，自引：0，他引：2  

Jorge Castro  César Sagaseta 《国际地质力学数值与分析法杂志》2009,33(7):851-877

A solution is presented for the radial consolidation around stone columns under constant surcharge load. The solution considers the influence of vertical and radial deformation of the column, either in elastic and elastoplastic regimes. The solution is in terms of the average excess pore pressure in the soil. It is based on previous solutions, initially developed for rigid column, or including only vertical deformation. For elastic column, the solution gives the variation of strains and stresses between the undrained and final states, for which it coincides with the existing elastic solutions. All the results are given in closed form, and both the elastic and plastic deformations of the column lead to an equivalent coefficient of consolidation for the radial flow, which enables the application of the existing methods of integration of the consolidation equation. A parametric study is presented, showing the influence of the main problem features. A design example is used to illustrate the application to practical cases. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Petrology, structure and tectonic significance of the Tuclame banded schists in the Sierras Pampeanas of Córdoba and its relationship with the metamorphic basement of northwestern Argentina     

Roberto D. Martino  Alina B. Guereschi  Jorge A. Sfragulla   《Journal of South American Earth Sciences》2009,27(4):280-298

In the northwest of the Sierras Pampeanas of Córdoba (Central Argentina), in the Tuclame area, rocks called ‘banded schists’ are recognized. They are known since 120 years ago and are one of the most important lithologies of the metamorphic complex in this region. The compositional banding is the most conspicuous structural mesoscopic feature, composed of quartz-rich and mica-rich layers. It is a tectonic banding produced by pressure solution during a compressive event. P–T conditions of 557 ± 25 °C and 3.9 ± 1 kb were obtained for the main metamorphic event. A detailed field checking allowed recognition of the banded schists as decimetric or centimetric xenoliths isolated within the regional migmatites and the anatectic granitoids and as kilometric-scale belts within Sierras de Córdoba and San Luis. The authors have also identified banded schists in the Sierras de Aconquija, Ambato, Ancasti and Guasayán. Other workers recognized them in the Puna, Cumbres Calchaquíes, Sierras de Quilmes and Fiambalá, among the most well known outcrops. The banded schists have systematic petrological features and a distinctive mesoscopic structure that allow their identification and correlation with the other outcrops, which are arranged as a huge belt 2000 km long and 150 km wide, between 64°00′–66°30′W and 25°00′–41°34′S. In this work, all these rocks are proposed to be integrated into the Puncoviscana Basin, since field evidence indicated that the banded schists transitionally pass by transposition to phyllitic rocks typical of this metamorphosed basin, which would cover a region of about 300,000 km². At present, there is no accurate geochronology available for the metamorphic and deformation events proposed in this work for the Tuclame banded schists. However, considering the regional geological evidence, the great spread of the petrostructural process forming these rocks, the transition between the Puncoviscana Formation and the banded schists, and the earlier idea that the Puncoviscana Formation is the shallowest equivalent of deeper structural levels in the Sierras Pampeanas, we favor for the moment the hypothesis that the banded schists could be part of the oldest evolution of the Pampean orogeny (early Pampean stage) and could represent different structural levels of the same orogen, probably a late Precambrian–early Palaeozoic orogen. The events of migmatization and emplacement of anatectic granitoids could represent a late Pampean stage of early Palaeozoic age. Thus, the Pampean orogeny could have lasted around 30–40 Ma (570–530 Ma).  相似文献