Metals
Mostrando 13-24 de 2170 artigos, teses e dissertações.
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13. Growth and accumulation of nutrients in papaya tree seedlings grown on organic substrates
ABSTRACT The use of organic waste for the production of plant substrates is an important environmental and economic alternative. In this perspective, we performed a work in a greenhouse, with the aim of evaluating the effect of substrates from organic waste during growth, gas exchange and accumulation of mineral elements in ‘Sunrise Solo’ papaya tree see
Rev. Ceres. Publicado em: 2021-08
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14. Adsorption of Calcium(II), Cadmium(II) and Copper(II) Ions from Water by Prepared Silicon-Aluminum-Zirconium Oxide Using Sol-Gel Process
Ternary oxide silica-alumina-zirconia (SiO2/Al2O3/ZrO2) obtained by the sol-gel process was applied as novel adsorbent of ions in aqueous solution. Batch isotherms were performed using standard CuII, CdII and CaII solutions at variable pH and different concentrations. Adsorption capacity was best at weakly acidic pH. The maximum adsorption capacities were 2.
J. Braz. Chem. Soc.. Publicado em: 2021-07
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15. Wavelength-Selective Near Unity Absorber Based on Fabry-Pérot Nanoresonators
Abstract We proposed and analyzed a planar narrow-band absorber based on a bi-layer metal/dielectric structure. The planar absorber uses the Fabry-Pérot resonance and the inherent loss of the metals, for maximum light absorption in the range of the electromagnetic spectrum visible to the near infrared. The absorption resonance peak can be shifted to other r
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2021-06
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16. Metal Distribution in the Environmental Compartments of Manguaba Lagoon (Alagoas State, Brazil)
The metal concentrations in water, sediments and mollusks (Tagelus plebeius) of the Manguaba Lagoon and the influence of humic substances from water and sediments in the distribution of these metals were investigated in this work. The mean metal concentrations in water were: Mg (89.0 ± 0.11), Ca (32.0 ± 0.10), Fe (0.97 ± 0.02), Mn (0.52 ± 0.01), Zn (0.33
J. Braz. Chem. Soc.. Publicado em: 2021-03
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17. Theoretical Study of the Reactivity of Phenyl Radicals Toward Enol Acetates
Arylation reactions are an important class of reactions and allow the synthesis of natural and synthetic products. Despite the efficient, but high cost and toxic methodologies involving transition metals, radical arylations have gained importance after the advent of photoredox catalysis. Arylation of enol acetates is an important tool for obtaining aryl keto
J. Braz. Chem. Soc.. Publicado em: 2021-02
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18. Mitral Valve Replacement with Regent Aortic Valve in Severe Mitral Stenosis
Arylation reactions are an important class of reactions and allow the synthesis of natural and synthetic products. Despite the efficient, but high cost and toxic methodologies involving transition metals, radical arylations have gained importance after the advent of photoredox catalysis. Arylation of enol acetates is an important tool for obtaining aryl keto
Int. J. Cardiovasc. Sci.. Publicado em: 2021-02
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19. Interaction of Pb, Ni and Cd with Aquatic Humic Substances of Amazonian Blackwater Rivers
In this study, the extraction and characterization of aquatic humic substances (AHS) from two blackwater rivers in the Amazon basin was carried out in order to assess the seasonal effects in the AHS structure. In addition, an investigation of the complexing capacities (CC) of the structures containing the metal ions CdII, NiII and PbII was also done. The cha
J. Braz. Chem. Soc.. Publicado em: 2021-02
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20. SEQUENTIAL MULTI-ELEMENT DETERMINATION OF TRACE-METALS IN BIODIESEL SAMPLES USING HR-CS FAAS
In this work the feasibility of sequential multi-element determination of Zn, Fe, Mg, Cu, Na, K, Cr, Al and Ca in biodiesel samples by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) was investigated. Biodiesel samples obtained from different sources and different chemical processes were analysed. The samples were diluted w
Quím. Nova. Publicado em: 2021-02
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21. Interaction of Suspended Particulate Material with Cd2+ and Pb2+ in a Brazilian Lagoon Estuarine System
The suspended particulate material (SPM) present in waters has fundamental importance for a better understanding of environmental behaviors of aquatic pollutants. This work determined the physicochemical parameters (pH, temperature, conductivity, total organic carbon and metals concentration) in water samples from Mundaú-Manguaba estuarine-lagoon system, Al
J. Braz. Chem. Soc.. Publicado em: 2021-01
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22. Technological innovation in Córrego do Sítio Mineração - A study of technical and economic aspects by using sensor-based sorting for refractory gold ore
Abstract The mining sector has a fundamental financial and economical role in the country where it practices these activities. In addition to employment creation and social-cultural development, the mining sector brings economic growth to the country. However, the sector is facing challenges due to COVID-19, incidents involving tailings dam facilities, risin
REM, Int. Eng. J.. Publicado em: 2021-01
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23. Arsenic and Other Elements Determination in Seawater Using Coprecipitation and Standard Mode Inductively Coupled Plasma Mass Spectrometry
The present work aims the determination of As, Co, Cr, Cu, Mn and Pb in seawater samples using coprecipitation extraction procedure before standard mode inductively coupled plasma mass spectrometry (ICP-MS) (no collision/reaction cell). The coprecipitation procedure is based on the precipitation of Mg(OH)2 from the reaction of the Mg2+ ions (present into the
J. Braz. Chem. Soc.. Publicado em: 2021-01
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24. Monitoring and health risk assessment of selected trace metals in wheat rice and soil samples
Abstract Wheat and rice constitute important cereal crops and any contamination may pose potential adverse impacts on human health. The study was conducted to determine eight trace metals, i.e. cadmium (Cd), copper (Cu), cobalt (Co), chromium (Cr), zinc (Zn), lead (Pb), nickel(Ni), manganese (Mn), in wheat, rice and soil samples collected from different citi
Food Sci. Technol. Publicado em: 2020-12