1000 resultados para Carência minerais


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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O trabalho foi realizado com o objetivo de estimar a retenção de elementos minerais durante a gestação de cabras com um ou dois fetos, utilizando-se diferentes modelos matemáticos. A estimativa de retenção foi baseada na diferença entre o total de cada mineral depositado no feto, útero, membranas, fluídos fetais e glândula mamária dos animais nas diferentes etapas da gestação e o total de cada mineral armazenado nas cabras vazias, utilizando-se os modelos de predição: ln Y = A - B e -C X ; Y = A e B X e ln Y = A + Bx + Cx², em que x = tempo de gestação. Comparando-se a estimativa com os valores reais obtidos, verificou-se que o modelo proposto ln = A+Bx+Cx², explicou com coerência e precisão o comportamento biológico da retenção de minerais durante todas as fases da gestação.

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O trabalho foi realizado com o objetivo de estimar a retenção e a exigência líquida dos minerais Na, K, Mg, S, Fe e Zn durante a gestação de cabras com um ou dois fetos. A estimativa de retenção foi baseada na diferença entre o total de cada mineral depositado no feto, útero, membranas, fluídos fetais e glândula mamária dos animais nas diferentes etapas da gestação e o total de cada mineral armazenado nas cabras vazias, utilizando-se o modelo de predição ln=A+Bx+Cx2, em que x=tempo de gestação. Os conteúdos de Na, K, Mg, S, Fe e Zn, durante as gestações de um e dois fetos foram de: 13,2 e 21,4 mg; 13,3 e 21,3 g; 2,1 e 3,7 mg; 5,5 e 9,3 mg; 575,5 e 981,0 mg; 112,6 e 164,7 mg nas gestações, resultando em exigências líquidas diárias de 0,13 e 0,11 g; 0,21 e 0,31 g; 0,06 e 0,11g; 0,17 e 0,21 g; 22,94 e 40,51 mg; 2,63 e 2,78 mg, respectivamente.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The search for alternative materials with lower density, reduction in heat transfer and propagation of noise associated with the ease of handling and application in concrete structures, represents an enormous challenge in the formulation and knowledge of the performance of self-compacting lightweight concrete, which has technology little known nationally, and appears on the international scene as an innovative material and alternative to conventional concrete. Based on these, this study set out to study self-compacting lightweight concrete made with two distinct grades of expanded clay associated with the addition of plasticizing/superplasticizers additives and mineral additions of metakaolin and bagasse ash of sugar cane. There is also an object of study, evaluation of pozzolanic activity of mineral admixtures and their influence on the durability characteristics of concrete. The rheological, physical, mechanical and microstructural analysis in this study served as basis in the classification of concretes autoadensáveis, targeting the national technical requirements for their classification in the category autoadensável and lightweight structural. The inclusion of mineral admixtures (metakaolin and bagasse ash of sugar cane), partial replacement of cement, pozzolanic activity and demonstrated maintenance of mechanical properties through the filler effect, a reduction of up to 76% of the nitrogen gas permeability in blend with 20% bagasse ash. All concretes had rheology (cohesion and consistency) suitable for self-adensability as well as strength and density inherent structural lightweight concrete without presenting phenomena of segregation and exudation

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With the current growth in consumption of industrialized products and the resulting increase in garbage production, their adequate disposal has become one of the greatest challenges of modern society. The use of industrial solid residues as fillers in composite materials is an idea that emerges aiming at investigating alternatives for reusing these residues, and, at the same time, developing materials with superior properties. In this work, the influence of the addition of sand, diatomite, and industrial residues of polyester and EVA (ethylene vinyl acetate), on the mechanical properties of polymer matrix composites, was studied. The main objective was to evaluate the mechanical properties of the materials with the addition of recycled residue fillers, and compare to those of the pure polyester resin. Composite specimens were fabricated and tested for the evaluation of the flexural properties and Charpy impact resistance. After the mechanical tests, the fracture surface of the specimens was analyzed by scanning electron microscopy (SEM). The results indicate that some of the composites with fillers presented greater Young s modulus than the pure resin; in particular composites made with sand and diatomite, where the increase in modulus was about 168 %. The composites with polyester and EVA presented Young s modulus lower than the resin. Both strength and maximum strain were reduced when fillers were added. The impact resistance was reduced in all composites with fillers when compared to the pure resin, with the exception of the composites with EVA, where an increase of about 6 % was observed. Based on the mechanical tests, microscopy analyses and the compatibility of fillers with the polyester resin, the use of industrial solid residues in composites may be viable, considering that for each type of filler there will be a specific application

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O trabalho teve como objetivo avaliar a tensão superficial estática de soluções aquosas com formulações de óleos minerais e vegetais emulsionáveis utilizados como adjuvantes na agricultura. Os óleos minerais e vegetais, quando adicionados aos produtos fitossanitários, podem imprimir características desejáveis à calda de pulverização, como reduzir a tensão superficial em soluções aquosas, possibilitar maior contato da calda com a superfície vegetal ou reduzir o potencial de deriva durante as pulverizações. Foram testados os seguintes produtos comerciais: óleos minerais (Assist, Attach, Dytrol, Iharol, Mineral Oil, Spinner, Sunspray-E e Triona) e óleos vegetais (Agrex'oil Vegetal, Crop Oil, Natur'l Óleo, Óleo Vegetal Nortox e Veget Oil), todos com registro de uso na agricultura. A tensão superficial das soluções aquosas foi avaliada em 11 concentrações para cada produto (0,025; 0,05; 0,1; 0,25; 0,5; 0,75; 1,0; 1,5; 2,0; 2,5 e 3,0% v/v). Essa propriedade dos óleos minerais e dos óleos vegetais foi estimada medindo-se a massa das gotas formadas na extremidade de uma bureta. Ao conjunto de dados obtidos para cada produto, na avaliação da tensão superficial, foram determinadas as análises de variância e de regressão, ajustando-se os dados ao Modelo de Mitscherlich. Entre os óleos minerais, destacaram-se os produtos: Assist, Dytrol, Iharol e Mineral Oil por apresentarem as menores tensões superficiais mínimas estimadas pelo Modelo, respectivamente, 29,255; 28,442; 26,097 e 28,584 mN m-1. Os óleos vegetais que apresentaram os menores valores de tensão superficial mínima estimados pelo Modelo, foram: Agrex' oil Vegetal (27,716 mN m-1), Natur'l óleo (28,216 mN m-1), Veget Oil (27,308 mN m-1) e Crop Oil (29,964 mN m-1).

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The pegmatite rocks in Rio Grande do Norte are responsible for much of the production of industrial minerals like quartz and feldspar. Quartz and feldspar are minerals from pegmatite which may occur in pockets with metric to centimetric dimensions or as millimetric to sub millimetric intergrowths. The correct physical liberation of the mineral of interest, in case of intergrowths, requires an appropriate particle size, acquired by size reduction operations. The method for treating mineral which has a high efficiency fines particles recovery is flotation. The main purpose of the present study is to evaluate the recovery of quartz and potassium feldspar using cationic diamine and quaternary ammonium salt as collectors by means of dissolved air flotation DAF. The tests were performed based on a central composite design 24, by which the influence of process variables was statistically verified: concentration of the quaternary ammonium salt and diamine collectors, pH and conditioning time. The efficiency of flotation was calculated from the removal of turbidity of the solution. Results of maximum flotation efficiency (60%) were found in the level curves, plotted in conditions of low concentrations of collectors (1,0 x 10-5 mol.L-1). These high flotation efficiencies were obtained when operating at pH 4 to 8 with conditioning time ranging from 3 to 5 minutes. Thus, the results showed that the process variables have played important roles in the dissolved air flotation process concerning the flotability of the minerals.

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The studied area is geologically located in the Northern Domain of the Borborema Province (Northeast Brazil), limited to the south by the Patos shear zone. Terranes of the Jaguaribeano system are dominant, flanked by the Piranhas (E and S sides) and Central Ceará (NE side) terranes. Its basement comprises gneiss -migmatite terrains of Paleoproterozoic to Archean age (2.6 to 1.9 Ga old), overprinted by neoproterozoic to cambrian tectonotherma l events. Narrow supracrustal belts ( schist belts) display a 1.6 to 1.8 Ga age, as shown by whole - rock Rb-Sr and zircon U-Pb and Pb/Pb dates in acid metavolcanics which dominate in the lower section of these sequences, and in coeval metaplutonics (granitic augen gneisses). From the stratigraphic point of view, three Staterian belts are recognized: 1. Orós Belt - made up by the Orós Group, subdivided in the Santarém (predominantly pure to impure quartzites, micaschists and metacarbonates) and Campo Alegre (metandesites, metabasalts, metarhyolites and metarhyodacites, interlayered with metatuffs and metasediments) formations, and by the Serra do Deserto Magmatic Suite (granitic augen gneisses). 2. Jaguaribe Belt - its lithostratigrahic-lithodemic framework is similar to the one of the Orós Belt, however with a greater expression of the volcano -plutonic components (Campo Alegre Formation and Serra do Deserto Magmatic Suite). The Peixe Gordo Sequence, separately described, is also related to this belt and contain s metasedimentary, metavolcanic (with subordinated volcanoclastics) and metaplutonic units. The first one correlated to the Orós Group and the latter the Serra do Deserto Magmatic Suite. 3. Western Potiguar Belt - represented by the Serra de São José Gro up, subdivided in the Catolezinho (biotite -amphibole gneisses with intercalations of metacarbonates, calcsilicate rocks, amphibolites and quartzite beds to the top) and Minhuins (quartzites, micaschists, metaconglomerates, calcsilicate rocks, acid to the b asic metavolcanics and metatuffs) formations. Its late Paleoproterozoic (Staterian) age was established by a Pb/Pb date on zircons from a granitic orthogneiss of the Catolezinho Formation. The petrographic characteristics and sedimentary structures of the Santarém Formation of the Orós Group point to deltaic to shallow marine depositional systems, overlain by deep water deposits (turbidites). The geodynamic setting of this region encompassed a large depositional basin, probably extending to the east of the Portalegre shear zone and west of the Senador Pompeu shear zone, with possible equivalents in the Jucurutu Formation of the Seridó Belt and in the Ceará Group of central Ceará. The Arneiróz Belt, west Ceará, displays some stratigraphic features and granito ids geochemically akin to the ones of the Orós Belt. The evolutionary setting started with an extensional phase which was more active in the eastern part of this domain (Western Potiguar and part of the Jaguaribe belts), where the rudite and psamite sedime ntation relates to a fluviatile rift environment which evolved to a prograding deltaic system to the west (Orós Group). The basaltic andesitic and rhyolitic volcanics were associated to this extensional phase. During this magmatic event, acid magmas also crystallized at plutonic depths. The Orós Group illustrates the environmental conditions in the western part of this domain. Later on, after a large time gap (1.6 to 1.1 Ga), the region was subjected to an extensional deformational episode marked by 900 Ma old (Sm-Nd data) basic rocks, possibly in connection with the deposition of the Cachoeirinha Group south of the Patos shear zone. In the 800 to 500 Ma age interval, the region was affected by important deformational and metamorphic events coupled with in trusion of granitic rocks of variable size (dykes to batholiths), related to the Brasiliano/Pan -African geotectonic cycle. These events produced structural blocks which differentiate, one from the other, according to the importance of anatectic mobilizatio n, proportion of high-grade supracrustals and the amount of neoproterozoic -cambrian granitoid intrusions. On this basis, a large portion of the Jaguaretama Block/Terrane is relatively well preserved from this late overprint. The border belts of the Jagua retama Block (Western Potiguar and Arneiroz) display kyanite-bearing (medium pressure) mineral associations, while in the inner part of the block there is a north-south metamorphic zoning marked by staurolite or sillimanite peak metamorphic conditions. Regarding the deformations of the Staterian supracrustal rocks, second and third phases were the most important, diagnosed as having developed in a progressive tectonic process. In the general, more vigorous conditions of PT are related to the interval tardi - phase 2 early-phase 3, whose radiometric ages and regional structuring indicators places it in the Brasiliano/Pan-African Cycle. In the Staterian geodynamic setting of Brazilian Platform , these sequences are correlated to the lower Espinhaço Supergroup (p.ex., Rio dos Remédios and Paraguaçu groups, a paleproterozoic rift system in the São Francisco Craton), the Araí and Serra da Mesa groups (north of Goiás, in the so -called Goiás Central Massif), and the Uatumã Group (in the Amazonian Craton). Granitic ( augen gneisses) plutonics are also known from these areas, as for example the A-type granites intrusive in the Araí and Serra da Mesa groups, dated at 1.77 Ga. Gravimetric and geological data place the limits of the Jaguaribeano System (terranes) along the Senador Pompeu Shear Zone (western border) and the Portalegre- Farias Brito shear zone (eastern and southern). However, the same data area not conclusive as regards the interpretation of those structures as suture of the terrane docking process. The main features of those shear zones and of involved lothological associations, appear to favour an intracontinental transpressional -transcurrent regime, during Neoproterozoic-Cambrian times, marking discontinuities along which different crustal blocks were laterally dispersed. Inside of this orogenic system and according to the magnetic data (total field map), the most important terrane boundary appears to be the Jaguaribe shear zone. The geochronological data, on some tectonostratigraphic associations (partly represented by the Ceará and Jucurutu groups), still at a preliminary level, besides the lack of granitic zonation and other petrotectonic criteria, do not allow to propose tectonic terrane assembly diagrams for the studied area

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This project was developed as a partnership between the Laboratory of Stratigraphical Analyses of the Geology Department of UFRN and the company Millennium Inorganic Chemicals Mineração Ltda. This company is located in the north end of the paraiban coast, in the municipal district of Mataraca. Millennium has as main prospected product, heavy minerals as ilmenita, rutilo and zircon presents in the sands of the dunes. These dunes are predominantly inactive, and overlap the superior portion of Barreiras Formation rocks. The mining happens with the use of a dredge that is emerged at an artificial lake on the dunes. This dredge removes sand dunes of the bottom lake (after it disassembles of the lake borders with water jets) and directs for the concentration plant, through piping where the minerals are then separate. The present work consisted in the acquisition external geometries of the dunes, where in the end a 3D Static Model could be set up of these sedimentary deposits with emphasis in the behavior of the structural top of Barreiras Formation rocks (inferior limit of the deposit). The knowledge of this surface is important in the phase of the plowing planning for the company, because a calculation mistake can do with that the dredge works too close of this limit, taking the risk that fragments can cause obstruction in the dredge generating a financial damage so much in the equipment repair as for the stopped days production. During the field stages (accomplished in 2006 and 2007) topographical techniques risings were used with Total Station and Geodesic GPS as well as shallow geophysical acquisitions with GPR (Ground Penetrating Radar). It was acquired almost 10,4km of topography and 10km of profiles GPR. The Geodesic GPS was used for the data geopositioning and topographical rising of a traverse line with 630m of extension in the stage of 2007. The GPR was shown a reliable method, ecologically clean, fast acquisition and with a low cost in relation to traditional methods as surveys. The main advantage of this equipment is obtain a continuous information to superior surface Barreiras Formation rocks. The static models 3D were elaborated starting from the obtained data being used two specific softwares for visualization 3D: GoCAD 2.0.8 and Datamine. The visualization 3D allows a better understanding of the Barreiras surface behavior as well as it makes possible the execution of several types of measurements, favoring like calculations and allowing that procedures used for mineral extraction is used with larger safety

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This dissertation deals with the characterization, distribution and provenience of heavy minerals along the Piranhas-Açu River, from the City of Parelhas (Seridó River) to your mouth at the City of Macau-RN. Many heavy minerals species were recorded in this study: clinoamphibole, epidote (including zoisite), garnet, sillimanite, tourmaline, staurolite, andalusite, zircon, rutile, augite, ilmenite, hematite and magnetite. Major transparent minerals, those forming more than 5% of some assemblages, are hornblende, epidote, tourmaline, staurolite and zircon. Predominant opaque mineral is ilmenite. Six assemblages were identified along the river: (i) Garnet-hornblende-tourmaline with sillimanite, when cutting rocks of the Seridó Formation; (ii) Hornblende-garnet-zircon, when crossing rocks of the Caicó gnaisse-migmatitic Complex; (iii) Hornblende-zircon-epidote-staurolite, when draining rocks of the Jucurutu Formation; (iv) Hornblende-zircon-epidote, when cutting rocks of the Açu Formation; (v) Hornblende-zircon-staurolite, on the lowermost Açu River, when crossing limestones of the Jandaíra Formation and (vi) Zircon-tourmaline-staurolite in the Açu River mouth (Cenozoic rocks) where coastal process dominate. Mineral ratios that reflect differences in grain shape, density, and selective chemical decomposition were used in an attempt to isolate the effects of source and process as controls of mineral variability. Reworking of the sediments was regionally effective in selective sorting; the more equant minerals (e.g. epidote) and heavier minerals (e.g. opaques) had a higher probability of being selected for permanent deposition during reworking. The processes of selective decomposition stand out at the river mouth. A priori knowledge of provenance, associated with the assemblage distribution and effects of process were utilized to the interpretations, that points to the follow provenances: hornblende comes from micashists of the Seridó Formation, orthognaisses and amphibolites of the Caico Complex, paragnaisses and paranphibolites of the Jucurutu Formation and granites intrusions; epidote comes from paragnaisses and calciosilicatics of the Jucurutu Formation, granites intrusions (-Npy3al/ca and -Npy3mz, gravels deposits and Açu Formation; Andalusite and staurolite come from the Seridó Formation; Sillimanite, tourmaline and garnet come from micashists of the Seridó Formation, as well as from quartzites of the Equador Formation; Zircon comes from Precambrian rocks (pink and prismatic zircon) and from sediments of several cycles (round zircon); Opaques come from all rocks cutted for the Piranhas-Açu River; Rutile comes from metamorphic rocks, in general; Augite comes from the Ceará-Mirim, Serra do Cuó and Macau volcanisms. The texture of gravels deposits reveals a sediment transport mechanisms by traction-current processes, together with a diagenetic clay matrix suggests a hot-humid environments for deposition. The presence of unstable heavy minerals assemblages, as well as pebbles of different composition and degrees of rounding and esfericity, indicate more than one source. The occurrence of calcio/alkaline granites suites, in areas closed to the gravel deposits, suggests that these intrusions are the main source of sediments. This could explain for instance, the significant amounts of epidote and presence of unstable heavy minerals (e.g. hornblende). The analyses of heavy minerals also show significante variability between the modern (Piranhas-Açu) and ancestral (Açu Formation) river sediments. In general, these variations reflect relatively higher unstable and lower stable heavy minerals contents of the modern Piranhas-Açu sediments. The absence of significant compositional differences probably reflects uniform weathering conditions

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A presente pesquisa foi realizada com o objetivo de comparar os efeitos de fontes orgânicas e inorgânicas de microminerais sobre o desempenho, os parâmetros sanguíneos e a deposição de minerais em tecidos e órgãos de leitões desmamados. Foram utilizados 54 leitões de genética comercial, desmamados com idade média de 24 dias e peso médio de 7,35±0,88kg, num delineamento experimental de blocos ao acaso, com dois tratamentos, nove repetições e três animais por parcela. Os tratamentos foram representados pelo uso de rações suplementadas com minerais de fontes orgânicas ou inorgânicas (Cu, Zn, Fe, Mn e Se) no período dos 24 aos 57 dias de idade. Foram avaliados o consumo diário de ração, o ganho diário de peso, a conversão alimentar, os parâmetros hematológicos e a deposição de minerais em tecidos e órgãos. As fontes orgânicas de minerais nas rações fornecidas dos 24 aos 57 dias de idade melhoraram o ganho diário de peso (P=0,06) e a conversão alimentar (P=0,05) e aumentaram o número de hemáceas (P=0,10), contudo não influenciaram a deposição de minerais no músculo masseter, fígado, coração, baço e rim. Portanto, o suplemento de minerais de fontes orgânicas foi mais eficiente para o desempenho dos leitões na fase de creche.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Com o objetivo de determinar os sintomas visuais de carência e os efeitos da omissão de micronutrientes na produção de materia seca e crescimento em altura de mudas de Pinus caribaea var. hondurensis, Pinus caribaea var. bahamensis e Pinus caribea var. cavibaea realizou-se um experimente com vasos, em casa de vegetação, em Piracicaba,SP. Foram empregados os-tratamentos: completo, com omissão de boro, com omissão de ferro, com omissão de manganês. e com omissão de zinco. Usou-se silica lavada como substrato, irrigando-se as plantas duas vezes ao dia com as soluções correspondentes. Após o estabelecimento dos sintomas de carência as plantas foram colhidas e separadas em acículas, ramos e raízes, secas a 75°C e pesadas. Descreveram-se os sintomas de carência, sendo bastante característicos os de Fe e B para as três variedades e os de cobre para P. caribaea var. hondurensis e P. caribaea var. bahamensis. A deficiência de cobre reduziu severamente a produção de matéria seca de P. caribaea var. bahamensis e P. caribaea var. caribaea. A deficiência de boro reduziu a produção de matéria seca de Pinus caribaea var. caribaea e a de ferro a de P. caribaea var. hondurensis. A deficiência de boro limitou preponderantemente o crescimento em altura de P. caribaea var. hondurensis.

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O objetivo deste trabalho foi avaliar, por meio da meta-análise, o efeito da fitase e da xilanase sobre a digestibilidade ileal aparente (DIa) de aminoácidos, cálcio e fósforo, em suínos em fase de crescimento. A base de dados consistiu de 21 artigos publicados entre 1998 e 2009, no total de 82 tratamentos e 644 suínos. A meta-análise foi realizada por análise gráfica, de correlação, de variância-covariância. As concentrações de fósforo fítico e as frações fibra em detergente neutro, fibra em detergente ácido e lignina em detergente ácido, nas dietas, apresentaram correlações baixas e negativas com a DIa do cálcio, fósforo e aminoácidos. A adição de fitase às dietas aumentou em 2% a DIa da arginina, em 14% a do cálcio e em 34% a do fósforo. A DIa da arginina, fenilalanina, isoleucina e lisina foi 3,3% superior em suínos alimentados com dietas com xilanase, em relação às dietas sem a enzima. O fósforo fítico e as fibras, nas dietas, reduzem a DIa do cálcio, do fósforo e dos aminoácidos essenciais. O uso de fitase e xilanase, nas dietas, melhora o aproveitamento de cálcio, fósforo e alguns aminoácidos. No entanto, o excesso de cálcio e fósforo nas dietas reduz a ação da fitase sobre a digestibilidade ileal dos nutrientes.