Weathering
Mostrando 1-12 de 168 artigos, teses e dissertações.
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1. Characterization of a complex carbonate-silicate apatite ore and its concentration by a two-stage anionic flotation method
Abstract A carbonate-silicate low weathering phosphate ore from an igneous origin deposit in Southeastern Brazil presents a challenge mainly for apatite flotation from its gangue minerals, calcite and dolomite, plus the presence of phlogopite, diopside, magnetite, richterite, ilmenite, vermiculite, quartz and many other minor impurities. Recently, selectivit
REM - International Engineering Journal. Publicado em: 2022
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2. Lignin-modified road marking paint: weathering aging studies
Abstract The accelerated artificial aging with ultraviolet radiation, viscosity, density, no-pick-up time, flexibility, and abrasion resistance of lignin-modified road marking paint were evaluated. The addition of lignin did not cause significant changes in the physical chemistry, flexibility and no-pick-time test compared to the precursor paint. The additio
REM, Int. Eng. J.. Publicado em: 2021-06
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3. Mineralogical characterization of copper lateritic ore from the Furnas deposit - Carajás, Brazil
Abstract Furnas is a small and not well-known copper sulfide deposit in the northern Carajás mineral province (Pará State, Brazil). Mineralogical and geochemical studies were performed on three weathered samples in order to verify the presence of copper in the lateritic minerals. According to these Cu-bearing minerals (malachite, e.g.), the weathered ore c
REM, Int. Eng. J.. Publicado em: 2020-09
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4. Minieditorial: Risco de FA após Ablação de Flutter Dependente de Istmo Cavo-Tricuspídeo: Vale a Pena Fazer a Ablação da FA Simultaneamente?
Considering the size of the Amazon region and the need for studies to establish soil trace metal concentrations in natural environments, the objective of this work was to evaluate heavy metal contents in a toposequence of an Amazon State microbasin. Soil samples were collected in three native forest topographic positions. Samples were opened for analysis by
Arq. Bras. Cardiol.. Publicado em: 2020-05
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5. VALORES DE REFERÊNCIA DA CONCENTRAÇÃO DE METAIS PESADOS EM SOLOS NA AMAZÔNIA CENTRAL
Considering the size of the Amazon region and the need for studies to establish soil trace metal concentrations in natural environments, the objective of this work was to evaluate heavy metal contents in a toposequence of an Amazon State microbasin. Soil samples were collected in three native forest topographic positions. Samples were opened for analysis by
Quím. Nova. Publicado em: 2020-05
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6. Zn2Al Layered Double Hydroxides Intercalated with Nitrate and p-Aminobenzoate as Ultraviolet Protective Agents in Low-Density Polyethylene Nanocomposites and Natural Insulating Oils
Zn2Al-Cl and Zn2Al-NO3 layered double hydroxides (LDHs) were synthesized through the fixed pH co-precipitation method and used as precursor materials for the intercalation of p-aminobenzoate through anion exchange reactions. Since chloride in Zn2Al-Cl was only partially exchanged with p-aminobenzoate, the phases Zn2Al-NO3 and Zn2Al-N -AB (nitrate exchanged w
J. Braz. Chem. Soc.. Publicado em: 2020-05
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7. SISTEMAS PEDOGEOMORFOLÓGICOS NA INTERPRETAÇÃO DA EVOLUÇÃO DE PAISAGENS QUATERNÁRIAS EM CLIMAS TROPICAIS ÚMIDOS
Resumo As relações entre solo e relevo são constantes em paisagens de climas tropicais e subtropicais úmidos, devido aos espessos mantos regolíticos resultantes de acelerado intemperismo físico, químico e biológico. A investigação dos sistemas pedogeomorfológicos merece destaque em análises sistêmicas, que objetivam o estudo da gênese e dos pro
Mercator (Fortaleza). Publicado em: 09/12/2019
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8. Weathering Resistance of Waterborne Polyurethane Coatings Reinforced with Silica from Rice Husk Ash
Abstract: Waterborne polyurethanes (WPUs) are interesting materials for coatings when compared to solvent-based polyurethanes, once that reducing the concentration of volatile organic compounds that are harmful for human health and the environment. However, the WPU has low weathering resistance. In order to improve this behavior among others properties, ino
An. Acad. Bras. Ciênc.. Publicado em: 25/11/2019
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9. Modeling and prediction of sulfuric acid digestion analyses data from PXRF spectrometry in tropical soils
ABSTRACT Sulfuric acid digestion analyses (SAD) provide useful information to environmental studies, in terms of the geochemical balance of nutrients, parent material uniformity, nutrient reserves for perennial crops, and mineralogical composition of the soil clay fraction. Yet, these analyses are costly, time consuming, and generate chemical waste. This wor
Sci. agric. (Piracicaba, Braz.). Publicado em: 04/11/2019
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10. Efeito do metal de adição na resistência ao desgaste por deslizamento de um aço estrutural soldado por GMAW
RESUMO O objetivo do presente trabalho foi avaliar o efeito do metal de adição na soldagem, e das microestruturas resultantes, na resistência ao desgaste de juntas soldadas de um aço estrutural ASTM A242, que possui resistência à corrosão atmosférica e é utilizado na fabricação de vagões destinados ao transporte de minério. As amostras foram sol
Matéria (Rio J.). Publicado em: 16/09/2019
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11. Micromorphology and Genesis of Soils from Topolitosequences in the Brazilian Central Plateau
ABSTRACT The micromorphology of deeply weathered soils (Ferralsols/ Latossolos ) from the Central Plateau of Brazil remains little studied, and its affiliation to different parent materials, poorly known. To clarify the processes of soil formation of these acric, gibbsitic, Fe-oxide rich Ferralsols, three lithotoposequences on local ultrabasic to basic intru
Rev. Bras. Ciênc. Solo. Publicado em: 09/09/2019
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12. Relief Position and Soil Properties under Continuous Banana Cropping in Subhumid Climate in Northeast Brazil
ABSTRACT Sequences of thick and eroded soils in hills surfaces are cultivated with banana since the beginning of the last century in the Northeast of Pernambuco (PE), Brazil. Measurements of soil properties depending on soil slope under intensive agricultural cultivation are limited mostly as the pedogenetic approach. This study aimed to identify the dominan
Rev. Bras. Ciênc. Solo. Publicado em: 09/09/2019