Iron Oxides
Mostrando 13-24 de 151 artigos, teses e dissertações.
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13. Study of Mechanical and Wear Behaviour of Hyper-Eutectic Al-Si Automotive Alloy Through Fe, Ni and Cr Addition
Effect of Fe, Ni and Cr addition on the wear behavior of hyper-eutectic Al-Si automotive alloy has been studied. Dry sliding wear tests have been conducted using pin-on-disc wear testing machine under normal loads of 20N and constant sliding speed of 0.64 ms-1. Influence of Fe addition to the base alloy increases the wear rate due to the formation of needle
Mat. Res.. Publicado em: 11/06/2018
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14. Effectiveness of Arsenic Co-Precipitation with Fe-Al Hydroxides for Treatment of Contaminated Water
ABSTRACT Wastewater treatment is a challenging problem faced by the mining industry, especially when mine effluents include acid mine drainage with elevated arsenic levels. Iron (hydr)oxides are known to be effective in removal of As from wastewater, and although the resulting compounds are relatively unstable, the presence of structural Al enhances their st
Rev. Bras. Ciênc. Solo. Publicado em: 29/03/2018
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15. Hourly, Daily, and Monthly Soil Temperature Fluctuations in a Drought Tolerant Crop
ABSTRACT Soil temperature is a physical property of great agricultural importance in the soil-plant relationship and in energy exchange with the atmosphere. This study was conducted in a degraded Cambissolo Háplico Ta Eutrófíco (Cambisol; Inceptisol) in the Irecê Identity Territory, Bahia, Brazil, aiming to evaluate the hourly, daily, and monthly fluctua
Rev. Bras. Ciênc. Solo. Publicado em: 22/01/2018
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16. Chemical and mineralogical characterization of silicon manganese iron slag as railway ballast
Abstract In nature, metal ores such as iron, lead, aluminum and others are found in an impure state, sometimes oxidized and mixed with silicates of other metals. During casting, when the ore is exposed to high temperatures, these impurities are separated from the molten metal and can be removed. The mass formed by these compounds is slag. Slag is the co-prod
REM, Int. Eng. J.. Publicado em: 2017-12
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17. Effect of PVA Concentration on Structure and Performance of Precipitated Iron-Based Catalyst for Fischer-Tropsch Synthesis
Fe2O3 catalysts were prepared by co-precipitation method with the assistance of polyvinyl alcohol (PVA) for Fischer-Tropsch synthesis. Effects of PVA concentration on structure and performance of the catalyst were investigated in a fixed reactor at 230-310 °C, 1.5 MPa, 2000 h-1, and syngas H2/CO = 2.0. The catalysts were characterized by N2 adsorption, scan
J. Braz. Chem. Soc.. Publicado em: 2017-08
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18. Organic Matter Stocks and the Interactions of Humic Substances with Metals in Araucaria Moist Forest Soil with Humic and Histic Horizons
ABSTRACT Soils with humic and histic horizons in tropical and subtropical ecosystems play an important role in determining the atmospheric C stock and its stabilization, climate regulation, water holding capacity, and environmental filtering, due to the different functions of soil organic matter (SOM). However, the processes and mechanisms that regulate SOM
Rev. Bras. Ciênc. Solo. Publicado em: 20/07/2017
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19. Facile Synthesis Strategy to Create Mesoporous Magnetic Iron Oxides Using Pectin-Based Precursors
Magnetic iron oxides are of great scientific and technological relevance. Therefore, herein, we report the research on developing methodologies for their sustainable and reproducible preparation. We discuss the synthesis of iron oxides involving citrus pectin as a source of energy (42 MJ kg-1) to promote the formation of the magnetic phases. The method invol
J. Braz. Chem. Soc.. Publicado em: 2017-07
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20. Copper Cobalt Magnetic Ceramic Materials Characterization at Terahertz Frequencies
ABSTRACT: This study presents the complex index of refraction and the complex permittivity of a magnetic ceramic material made of copper, cobalt, and iron oxides. The index of refraction and the extinction coefficient of the CuCo-ferrite exhibit an almost frequency independent behavior and were averaged to n = 3.62 ± 0.05 and k = 0.06 ± 0.02, respectively,
J. Aerosp. Technol. Manag.. Publicado em: 2017-06
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21. Clays for Brick Manufacturing in Actopan, Hidalgo: Physical, Chemical and Mineralogical Characterization
Samples of clays from Actopan, Hidalgo employed in brick manufacturing are physical, chemical and mineralogical characterized. Transmitted polarized light microscopy showed a uniform particle size with grain morphology characteristic of euhedral crystals with quartz, feldspars, nontronite, and iron oxides particles. Scanning Electron Microscopy revealed 75 �
Mat. Res.. Publicado em: 11/05/2017
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22. Pedogenic Iron Oxides in Iron-Rich Oxisols Developed from Mafic Rocks
ABSTRACT Despite the considerable amount of information on the mineralogical characteristics of pedogenic Fe oxides in Brazilian soils, there are few studies on Fe-rich soils developed from mafic rocks with taxonomic identities at lower categorical levels. This study evaluated the mineralogical characteristics of pedogenic Fe oxides in B horizons (Bw) of Fe-
Rev. Bras. Ciênc. Solo. Publicado em: 27/04/2017
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23. Kinetics of Thermal Transformation of Synthetic Al-Maghemites into Al-Hematites
ABSTRACT Maghemite (γ-Fe2O3) and hematite (α-Fe2O3) are important iron oxides in Brazilian soils derived from basalt. Maghemite can transform into hematite when exposed to high temperatures. However, isomorphic substitution (e.g., Al3+) may largely influence this process. We analyzed the kinetics of thermal transformation of Al-maghemites into Al-hematites
Rev. Bras. Ciênc. Solo. Publicado em: 27/04/2017
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24. Remediação de solos contaminados por processos fenton: uma revisão crítica
The remediation of contaminated soils is probably one of the biggest environmental challenges, mainly due to the complex dynamics of the pollutants in this medium. Among a variety of treatment alternatives proposed for the in-situ remediation of contaminated soils, Fenton processes appear as the most cost-effective, particularly when catalyzed by native iron
Quím. Nova. Publicado em: 2017-04