Elemental Composition
Mostrando 1-12 de 128 artigos, teses e dissertações.
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1. Avaliação da concentração e composição inorgânica do material particulado coletado no estado do Rio de Janeiro
Cities urbanization and modernization increase emission sources, contributing to particulate matter (PM) composition heterogeneity and enhance the risk to human health and environment. This paper intends to survey the studies on particulate matter carried out in the state of Rio de Janeiro. The sampling of PM is generally made using Hi-Vol samplers to collec
Quím. Nova. Publicado em: 2021-06
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2. EVALUATION OF THE CHEMICAL COMPOSITION AND STRUCTURE OF ASPHALTENES FROM THREE OFFSHORE BRAZILIAN BIODEGRADED HEAVY OILS
Asphaltenes fractions were extracted and purified from three heavy Brazilian oils. Their mass compositions of C, H, N, Ni and V were obtained from elemental analysis and S and O atomic percentages from EDS. The H/C ratios showed high degree of unsaturation, while the O atomic percentages indicated more pronounced biodegradation effects on two samples. Quanti
Quím. Nova. Publicado em: 2021-04
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3. SYNTHESIS, CHARACTERIZATION, DFT MODELING AND IN VITRO ANTIMYCOBACTERIAL ACTIVITY ASSAYS OF A SILVER(I)-ISONIAZID COMPLEX
In the present work, a silver(I) complex with the antimycobacterial drug isoniazid (inh) is described. Elemental and thermogravimetric analyses confirmed a 1:1 metal:ligand ratio for the silver-isoniazid (Ag-inh) complex with molecular composition AgC6H7N3O·NO3. Infrared (IR) analysis suggests a bidentate coordination of isoniazid to silver by the nitrogen
Quím. Nova. Publicado em: 2021-03
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4. Using static, kinetic and metal mobility procedures to evaluate possibilities of coal waste land disposal at Moatize Mine, Mozambique
Abstract Coal mine waste rocks produced during mining and beneficiation can affect the environment due to land degradation and acid mine drainage generation. However, proper characterization and treatment of mineral processing wastes creates options for safe disposal, enhancing the environmental performance. The aim of this study was to use static and kineti
REM, Int. Eng. J.. Publicado em: 2020-12
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5. Elemental Composition of Particulate Matter in the Southeastern Brazilian Ceramic Pole by Synchrotron Radiation X-ray Fluorescence Technique (SR-XRF)
In the present study, the elemental content of the particulate matter PM2.5 (particulate matter with diameters lower than 2.5 µm) and PM10 (particulate matter with diameters lower than 10 µm) of the Brazilian city of Rio Claro (SP) were analyzed by synchrotron radiation X-ray fluorescence (SR-XRF) in the Brazilian Synchrotron Light Laboratory (LNLS). A fra
J. Braz. Chem. Soc.. Publicado em: 2020-06
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6. Dielectric and Magnetic Properties of Epoxy with Dispersed Iron Phosphate Glass Particles by Microwave Measurement
Abstract This paper investigates the dielectric properties and magnetic properties of epoxy composites with different amount of powdered iron phosphate glass (IPG) at 8.2 GHz to 12.4 GHz using microwave technique. IPG composed of 60P2O5-40Fe2O3 (mol%) was produced by conventional melt and quenching method and crushed into powder. The IPG powder was character
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2020-06
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7. ANÁLISE ESPECTROSCÓPICA DA MATÉRIA ORGÂNICA NO SEDIMENTO SUPERFICIAL DA BAÍA DE SEPETIBA, RIO DE JANEIRO, BRASIL
Spectroscopic techniques are powerful tools for molecular organic matter assessment in sediments, which analysis request low sample mass and are cheap, fast and easy to obtain. The aim of this work was to evaluate the elemental (C, N) and molecular composition of the organic matter in relation to the grain-size distribution over surface sediments from Sepeti
Quím. Nova. Publicado em: 2020-05
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8. Screening of the Au:Pt Atomic Ratio Supported in SrCO3: Effects on the Performance of the Solvent-Free Oxidation of Benzyl Alcohol
We have prepared, by a sol-immobilization method, bimetallic catalysts with different Au:Pt atomic ratios supported on commercial SrCO3. The catalytic performance for the oxidation reaction of benzyl alcohol of such materials was compared to the monometallic counterparts, aiming at the obtaining of the best composition of the material. It was found that the
J. Braz. Chem. Soc.. Publicado em: 2020-03
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9. Obtaining and characterization of anthocyanins from Euterpe oleracea (açaí) dry extract for nutraceutical and food preparations
Abstract The main constituents of the Euterpe oleracea Mart., Arecaceae, fruits (açaí) are anthocyanins. This paper aimed to standardize the extraction process and characterize an anthocyanin-rich dry extract obtained from this fruit. A 23 full factorial design was used. The volumes of ethanol 92% and acetic acid and the extraction time were used as factor
Rev. bras. farmacogn.. Publicado em: 09/12/2019
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10. Corrosion Resistance of TiO2-ZrO2 Nanocomposite Thin Films Spin Coated on AISI 304 Stainless Steel in 3.5 wt. % NaCl Solution
Utilizing high chromium and nickel content in AISI 304 steel confers its good corrosion resistance. However, the high content of chromium and nickel increases the steel susceptibility to corrosion caused by the high concentration of chlorine. Consequently, the electrochemical and mechanical performance of the steel degrades. In this study, the effect of addi
Mat. Res.. Publicado em: 02/12/2019
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11. How increased atmospheric carbon dioxide and ‘The Law of the Minimum’ are contributing to environmental obesity
Resumo Justus von Liebig observou que era possível aumentar a produção agrícola adicionando pequenas quantidades de nitrogênio (N), fósforo (P) e potássio (K) aos solos. Essa descoberta levou a mais recente revolução agrícola. Contudo, uma vez que a maioria das plantas e microrganismos podem ser não-homeostáticos em relação a composição quím
Acta Limnol. Bras.. Publicado em: 28/11/2019
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12. 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