951 resultados para Ni–Cu deposit


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The Permo-Carboniferous Harare Group crops out in the Matra area, represented by Campo do Tenente, Mafra and Rio do Sul formations; they correspond in subsurface to Lagoa Azul, Campo Mourão and Tacïba formations. A composite sampling of the Group was performed through drilling of six wells, which average 60 m in depth; three of them cored the depositional sequence here designated as Upper Mafra\Lower Rio do Sul. The Upper Mafra Formation were sampled by TC-4 and BR-5 wells, and it consists of three units: the lower two are sandy, glacial-deltaic and fluvial-deltaic in origin, corresponding to a lowstand tract. The last unit is composed of two dirtying-upward successions of sandstone, diamictite and rhythmite, interpreted as deglaciation/transgressive events, and well represented in BR-5 drilling. The Lower-Rio do Sul Formation (Lontras Shale) is formed by two marine units: the lower one is represented by shale and bioturbated siltstone which culminate the previous deglaciation, transgressive succession, while the upper one, sampled by SL-2 well, is formed by shale and thin, turbidite sandstone, attributed to a highstand tract.

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A comparative study was accomplished between two immobilization methodologies for the meldola's blue (MB), used to decrease the oxidation potential of NADH. The study was performed with glassy carbon electrode by electropolymerization of pyrrole and MB through the technique of cyclic voltammetry being evaluated the effect of the number of cycles to define the thickness and the stability of the film. With 25 cycles it was obtained the best result. They were also investigated the modification of the graphite electrode with film formed by the system sol-gel PPO 300 or PPO 4000 for the dip-coating, through two methods: occlusion and adsorption. The best method was it of adsorption of MB during 10 min, following by deposit of the film PPO 300, favored for the time of drying (24 hours). The adsorption of MB followed by PPO 300 deposition presented broader linear range than PPy methodology. ©2006 Sociedade Brasileira de Química.

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Rhythmite samples from Varvite Quarry and Park of Itu (SP), and well cores from Rafard (SP), were analyzed by optical microscopy to describe the petrographic characteristics of their light-colored (siltstone) and dark-colored (shale) laminae. The light-colored ones are essentially siltstones, commonly with traces of sands; the mineralogical composition is mainly quartz, with traces of feldspar and scarce mica; quartz or calcite cementation occurs in variable intensity, the first one being more intense in the Itu rhythmites; parallel laminations, internally normal graded or massive are the most common sedimentary structures in these rocks; bioturbations and dropstones are commonly observed in Itu rhythmites; contacts between siltstone laminae, and siltstone beds and shale laminae are commonly non-erosive and sharp. Considering this study and the macroscopic description of these rhythmites it was possible to clarify many questions about their composition, as the grain-size of the light-colored beds composed by silt with subordinate dropped sand, and the inappropriate use of the term varvite to the most of the Itu rhythmites. It was also important to reinforce their proglacial lacustrine origin, with random freezing of lacustrine surface water, and only sporadic ice-contact.

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Deposits formed on the surface of. paper were analysed in order to identify the sources of the defects, as well as to solve the problems associated with performance and adjustments at the wet end of the paper forming process. Standard paper samples containing deposits were collected and analysed by comparing the microstructure and composition of the deposit with paper regions adjacent to it. Optical microscopy (OM). energy dispersive X-ray microanalysis (EDX) X-ray powder diffraction (XRD). thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were the techniques used in this study. The results obtained from the EDX, XRD. and TG techniques allowed concluding that the calcium carbonate content in the farm of calcite is 1.6 times higher in the formed deposit them the quantity expected in the standard paper composition. The paper sample microstructure revealed by the SEM images indicates the presence of irregular spherical aggregates up to 20μm in diameter in the deposit region. containing larger amount of calcium carbonate as well as in the regions adjacent to the deposit. These spherical aggregates seem to be absorbed and integrated into the pulp fibres and present characteristics similar to those of partially cooked cationic starch. The analysed deposits are characterised by a dense and thick substance, forming a plate with highly adhesive property. This adhesive substance has a characteristic similar to glue with a large amount of organic matter due to the high weight loss shown by the TG curve. The results are consistent with the interaction ofparticles of negatively charged calcium carbonate and cationic starch, forming sterically stabilized deposits, which firmly adhere to the paper microstructure.

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The inadequate land use in the low course of the river Acaraú is speeding up processes of erosion in some degrees. This process is accented in the areas where caatinga was removed for implantation of pastures and agriculture. Concomitantly, the plain of flooding of the river Acaraú an accumulation of sand with the carry of these sediments, resulting in the widening of the fluvial plain and reduction of the shape water, with increase of the evapotranspiration and consequence salinization, proceeding from the local substratum. This paper aimed at the crossing of diverse space information (geomorfology, soil, declivity, geology and land use) in environment SIG, for determination of the susceptible areas to the erosion and an accumulation of sand in the low course of the Acaraú river, north of the State of the Ceará, Brazil. The results allow to evaluate the application of this tool in the planning and management of the environment, from the crossing of the type of use with the used environment and the consequent impact to the ecosystem.

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The osseointegration of porous titanium implants was evaluated in the present work. Implants were fabricated from ASTM grade 2 titanium by a powder metallurgy method. Part of these implants were submitted to chemical and thermal treatment in order to deposit a biomimetic coating, aiming to evaluate its influence on the osseointegration of the implants. The implants were characterized by Scanning Electron Microscopy (SEM), Electron Dispersive X-Ray Spectroscopy (EDS) and Raman Spectroscopy. Three coated and three control (uncoated) implants were surgically inserted into thirty albino rabbits' left and right tibiae, respectively. Tibiae samples were submitted to histological and histomorphometric analyses, utilizing SEM, optical microscopy and mechanical tests. EDS results indicated calcium (Ca) and phosphorous (P) at the surface and Raman spectra exhibited an intense peak, characteristic of hydroxyapatite (HA). Bone neoformation was detected at the bone-implant interface and inside the pores, including the central ones. The mean bone neoformation percentage in the coated implants was statistically higher at 15 days, compared to 30 and 45 days. The mechanical tests showed that coated implants presented higher resistance to displacement, especially after 30 and 45 days.

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Fluvial morphometry is method of great value regarding neotectonic analysis of extensive areas because streams, besides representing one of the main agents in the relief modeling, quickly adjust their thalwegs to even the most gentle crustal deformations. The purpose of this paper is to present the application of some morphometric techniques in the Santo Anastácio River hydrographic basin in order to identify recent tectonic deformations. Additionally, we show liquefaction structures identified in the basin and interpreted here as seismites linked to ancient earthquakes (magnitudes greater than 5). The morphometric survey includes longitudinal stream profile analysis, RDE (declivity versus stream length) index application, and the sinuosity study of the Santo Anastácio River channel. Geologic substrate comprises Cretaceous siliciclastic rocks of the Caiuá and Bauru groups, locally covered by Cenozoic sediments (alluvial plains, terrace deposits, colluvial aprons, as well as in situ regoliths). Considering that liquefaction structures affect dark clay layers of 32.340±320 year BP age (14C dating), a lower age limit for the ancient earthquake is triggered in that region. The authors believe that neotectonic understanding of the Western São Paulo State Plateau is important to the geologic and geomorphologic evolution of that landscape and to the consequent territorial planning and occupation.

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The study area comprises the western portion of the Marília Plateau, State of São Paulo, southeastern Brazil. The geological substrate encompasses Cretaceous sedimentary rocks of the Bauru Group and local Neocenozoic units like colluvium aprons, fluvial terrace deposits, in situ regoliths, and modern alluvial deposits. In a geomorphologic sense, the study area might be characterized as showing two main pediplanes, viz. P1 Surface (upper) and P2 Surface (lower), both surfaces are presently under dissecation processes. After the 1920's the expansion of the railroad system fostered the removal of the natural vegetation, which in turn was followed by the introduction of coffee, peanut, corn and cotton crops. This intense exploitation was conducted without respect to the soil carrying capacity and its natural susceptibility to erosional processes, including an aggressive form known as voçoroca. As a result, the study shows that the most susceptible material includes colluvium aprons, in situ regoliths, and colluvium-alluvium or alluvium deposits. The most critical situation is in the P2 Surface context, near the bottom of the Marília Plateau scarpment, where surface runoff can be very strong. Another point of active erosion is represented by the exposed walls of gullies and voçorocas, mainly in fluvial reaches subjected to talweg lowering. In a general sense, this study shows current evidence of erosional stability due to the ìntroduction of pastures as a predominant type of land occupation and to a series of erosion control procedures. Among these actions are terrace implantation, construction of small pits for runoff control, natural or induced reforestation by land owners. Despite these efforts, some erosion points remain chiefly in steeper country roads and trail stretches, in areas of concentration of cattle tracks (e.g., near cattle ponds), gullies or voçorocas exposed walls, and badly planned urbanization. The permanence of these erosion points demonstrates the necessity of a continuous monitoring of surface dynamics as well as a rapid and effective intervining measures of erosion and/or silting control.

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Rio Apa Massif crops out in the Mato Grosso do Sul state and corresponds to the southeastern portion of the Amazonian Craton dominantly Paleoproterozoic in age. Rio Apa Complex is oldest and it is composed mainly by migmatitic orthogneisses, beyond amphybolites, tonalities and granodiorite. Alto Tererê Group is composed by schists, biotitemuscovite gneisses and micaceous quartzites generally rich in garnets, beyond metabasic rocks of low amphibolite facies. The Amoguijá Group is constituted by Alumiador Intrusive Suite, which is represented by a sieno to monzogranitic batholith and Serra da Bocaina Volcanic Suite composed of volcanoclastic rocks of alkali riolites to monzoriolites compositions and pyroclastic products. Overlaying towards East and South occurs Neoproterozoic metasedimentary rocks from the Paraguai Folded Belt (Cuiabá, Corumbá and Jacadigo Groups - Urucum Formation). Structural-metamorphic framewok is identified by five deformational phases but the actual tectonic and metamorphic structure shows the superposed tectonic array of the Paraguai Folded Belt. Rocks from Rio Apa Complex, Alto Tererê Group and Amoguijá Group record an older structural evolution defined by (Dn-1 and Dn). The deformational phases (Dn+1 and Dn+2) are visible mainly in rocks of Paraguai Folded Belt beyond the last deformation (Dn+3) that imprints all sequences.

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The region of Alfenas, in the state of Minas Gerais, Brazil, is predominantly constituted of Pre-Cambrian rocks with well developed alteration profiles in association with colluvial and alluvial sediments. No study to date has examined in detail its potential use in the ceramic industry. The scarce knowledge of its mineralogical and technological properties limits its value and consequently its industrial use. Until now, these clay materials have been used in a rudimental manner, in small scale in the fabrication of red tiles. The present study aimed at analyzing these clays mineralogically (X-ray diffraction), chemically (major and minor elements by X-ray fluorescence and organic carbon analysis) and technologically (pressing granulometric distribution; mechanical resistence; water absorption, apparent porosity; linear firing shrinkage; color of firing and others) in order to better understand the raw material and develop adequate technological applications. The best results of ceramic properties were the samples with higher organic content (more plastic clays) and higher values of Al2O3 (kaolinite and gibbsite) and Fe2O3 as well lower SiO2 content and finer grain size which contribute to a better sinterization.

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Aiming at improving the efficiency control of Phakopsora pachyrhizi, this research evaluated different application techniques, using spray deposits and yield parameters of soybean crop. Two experiments were carried out in the experimental area of FCA/UNESP - Botucatu, SP, Brazil, in the soybean crop, Conquista variety, in the 2006/2007 season. The first experiment was arranged in random blocks with eight treatments and four replications. The treatments were conducted in factorial arrangement 4×2 (four air levels 0, 9, 11 and 29 km/h combined at two nozzle angles 0 and 30°) using AXI 110015 nozzles. Ten plants on each plot were selected for sampling spray deposits. Artificial targets were fixed on plants, two in the top and another two in the bottom part of plants (abaxial and adaxial leaf surface each one). For deposit evaluations, a cupric tracer was used and the amount of deposits was determined by a spectrophotometer. The second experiment was carried out in the same place and the treatments were of the same arrangement as the previous experiment, including control treatment (untreated plants). The spraying with triazole fungicide was realized in R2 and R5.2 growth stages of soybean with 142 l/ha spray volume. The nozzle angled of 30° combined with maximum air speed promoted the highest spray deposits on the soybean crop and influenced positively the control of the soybean Asian rust as well in the productivity of this crop.

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Includes bibliography

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A few examples of supergene ore formation and their interaction with morphogenesis (palaeosurfaces) and weathering mineralogy are discussed. Geomorphological and mineralogical records to characterize palaeosurfaces associate the weathering of primary minerals and their relationship with concentrations of cooper and iron ore deposits in southeastern state of São Paulo, Brazil. We have distinguished two palaeosurfaces generated by several weathering phases and controlled by the geological framework. The first and oldest upper palaeosurfaces (900 - 1000 m a.s.l.), situated in Riberão Branco (Alto do Brancal), were developed on silico-limestones. It is formed by typical iron laterites enriched by secondary products of cooper. The second and younger level palaeosurfaces located in Itapeva (Santa Blandina and Bairro do Sambra). This palaeosurface is formed by copper percolating through the weathered rock (saprolite). Other features can be observed like neo-formed products in laterites. They are classified into two types: clay like silico- cupriferous products (with noticeable amounts of iron) and copper minerals (crysocolla, in their flat slopes). These features allowed the presence of copper ores and their morphogenesis control will help in the exploration and prospecting of supergene ore mineral.

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The objects of this study are three manganese ore deposits and one mine derived from lateritic weathering of gondites (spessartine quartzites). These deposits are associated with Mn-rich garnet metasediments of the Itapira Group (Paleoproterozoic) and the reserves were estimated at approximately 2.0 × 10 6 tons with an average grade of 23% MnO 2. The ore minerals are cryptomelane, pyrolusite, lithiophorite, spessartine and psilomelane. Several crystal shapes and textural characteristics were identifi ed in this study, which are related to the degree of liberation, as confi rmed by heavy media separation method. In this study, we determined the main characteristics of the liberation of manganese, which is concentrated in the fi ne grain-size fraction and is lost during ore dressing. Therefore, the low average content of MnO 2 (28%) is due to this loss, whereas at grain size of minus 0.074 mm, contents near 40% MnO 2 were observed. This suggests that the ore can be used for manufacturing manganese sulphate fertilizers. A comparative study with the ore deposits located at Ouro Fino (MG), mainly with the Caneleiras mine, showed that higher degree of liberation occurs in the coarse grain-size fractions (0.84 to 0.074 mm with MnO 2 content of 38%). As a consequence, the ore can be used for manufacturing Fe-Si-Mn alloys.

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The study aimed to evaluate the performance of air assistance in spray booms using different types of nozzles and spray volumes. We took into account spray deposits, fall armyworm control and crop corn performance in a narrow row cropping system. The experiment was carried out at the experimental area of Sao Paulo State University, Botucatu/SP, Brazil, during the 2008/2009 agricultural season, in randomized blocks with a factorial scheme (2×2+1) and four replications. Two spray nozzles (flat fan nozzle and hollow cone nozzle) were tested, combined with two air assistance levels in the spray boom (with and without air assistance) and a treatment control. In the experimental spraying, Spinosad insecticide was sprayed in amounts of 48 g active substance (a.s.)/ha. The air assistance in the spray boom increased the spray deposits in the V 4 growth stage of the corn plants. Moreover, the application of this technology showed higher efficiency on fall armyworm control, reaching a 100% level 15 days after spraying, in the V 10 growth stage of the plants. The hollow cone nozzle increased the spray deposit level on the corn plants compared with the flat fan nozzle, at growth stage V 4. However, the flat fan nozzle, combined with air assistance technology, was more effective for controlling fall armyworm in the same growth stage (V 4), although the hollow cone nozzle increased the deposit levels on the plants. All the technologies tested in the study promoted a reduction of plant damage from fall armyworm attack. Corn productivity is directly related to the control efficiency of fall armyworm.