Elemental Composition
Mostrando 25-36 de 128 artigos, teses e dissertações.
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25. Catalytic hydrogen generation from NaBH 4 /H 2 O system: effects of catalyst and promoters
Abstract A hydrogen generation system based on NaBH4 hydrolysis is affected by the nature of the catalyst and catalyst promoter. Various catalyst promoters such as Al2O3 nanoparticles, Al2O3 particles, ZrO2 sand, SiO2, MMT clay, CNT and zeolite are compared with respect to hydrogen generation (HG) and hydrogen generation rate (HGR). The highest HG and HGR ar
Braz. J. Chem. Eng.. Publicado em: 2018-01
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26. Elemental composition of vegetables cultivated over coal-mining waste
ABSTRACT We assessed elemental composition of the liver in mice subjected to one-time or chronic consumption of the juice of vegetables cultivated in a vegetable garden built over deposits of coal waste. Lactuca sativa L. (lettuce), Beta vulgaris L. (beet), Brassica oleracea L. var. italica (broccoli) and Brassica oleracea L. var. acephala (kale) were collec
An. Acad. Bras. Ciênc.. Publicado em: 23/10/2017
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27. Synthesis and Structural Characterization of U-Zr-Nb Alloys
U-xZr-yNb alloys with values of x varying from 32% to 50% (wt.%Zr) and y varying from 6% to 10% (wt.%Nb) were produced by the arc melting technique. The effect of the addiction of zirconium and niobium on the phase stabilization of γ-U, lattice parameter, microstructure and elemental composition were examined by X-ray diffraction (XRD), scanning electron mi
Mat. Res.. Publicado em: 16/10/2017
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28. Anatomical characterization of ultra-structures, biominerals and histolocalization of metabolites in leaves of Genipa americana
Abstract Inserted in one of the largest families among the Angiosperms, Genipa americana L., Rubiaceae, can be found in all Brazilian territory, presenting great medicinal importance, where several uses have been attributed. In view of this, this work has the purpose of analyzing the ultrastructural, biomineral, phytochemical and histochemical characteristic
Rev. bras. farmacogn.. Publicado em: 2017-10
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29. Impact of Ni Substitution on Structural, Electrical and Thermoelectrical Properties of Zinc Alluminium Chromites Synthesized by sol-gel Route and their Photocatalytic Investigation
Nanostructured nickel substituted zinc alluminium chromites (Zn1-xNixAlCrO4, where, x= 0.0, 0.25, 0.50, 0.75, 1.0) were prepared by simple, cost effective, sol-gel autocombustion method. Temperature of phase formation was analyzed by thermogravimetric and differential thermal analysis (TGA/DTA). Crystallographic studies of all the samples show formation of s
Mat. Res.. Publicado em: 17/08/2017
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30. Impact of HNO3 Solution Treatment of South Brazil Coal Matrices on Their Chemical Composition and Humic Acids Yield
In this study, changes on the chemical composition and on the humic acids yield of coal matrices promoted by 25% HNO3 treatment were investigated, by means of elemental, thermogravimetric analyses, and Fourier transform infrared spectroscopy (FTIR). The "run of mine" (ROM) matrix C-MTR (ROM coal) showed the highest C content (41%), highest C/N ratio (76) and
J. Braz. Chem. Soc.. Publicado em: 2017-05
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31. Enhanced bioactive properties of BiodentineTM modified with bioactive glass nanoparticles
Abstract Objective To prepare nanocomposite cements based on the incorporation of bioactive glass nanoparticles (nBGs) into BiodentineTM (BD, Septodent, Saint-Maur-des-Fosses Cedex, France) and to assess their bioactive properties. Material and Methods nBGs were synthesised by the sol-gel method. BD nanocomposites (nBG/BD) were prepared with 1 and 2% nBG
J. Appl. Oral Sci.. Publicado em: 2017-04
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32. Multielement Determination of Macro and Micro Contents in Medicinal Plants and Phytomedicines from Brazil by ICP OES
In this study, the elemental composition of nine medicinal plants and phytomedicines was evaluated by using axial view inductively coupled plasma optical emission spectrometry (ICP OES) after three digestion procedures: dry ashing (DA) and two wet digestions with a mineral acid (HNO3/H2O2) mixture on a conventional hot plate (CD), besides microwave digestion
J. Braz. Chem. Soc.. Publicado em: 2017-02
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33. BIOLEACHING OF METALS FROM A SPENT DIESEL HYDRODESULFURIZATION CATALYST EMPLOYING Acidithiobacillus thiooxidans FG-01
Abstract This study evaluates the recovery of heavy metals employing a spent catalyst from the hydrodesulfurization (HDS) of diesel, with no chemical, thermal or physical pretreatment, using the bacterial strain Acidithiobacillus thiooxidans FG-01. Direct and indirect bioleaching tests were carried out in Erlenmeyer flasks (500 mL). The influence of the pulp
Braz. J. Chem. Eng.. Publicado em: 2017-01
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34. Elemental composition of PM10 and PM2.5 for a savanna (Cerrado) region of southern Amazonia
Brazil plays an important role with regard to the emission of aerosols into the atmosphere. Ecosystems such as the Amazonian tropical forest and Brazilian Cerrado are undergoing sweeping changes. These human activities promote an increase in the levels of gases and particles emitted into the atmosphere. To determine how these activities have affected the emi
Quím. Nova. Publicado em: 2016-12
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35. COMPARISON BETWEEN ASPHALTENES (SUB)FRACTIONS EXTRACTED FROM TWO DIFFERENT ASPHALTIC RESIDUES: CHEMICAL CHARACTERIZATION AND PHASE BEHAVIOR
Asphaltenes are blamed for various problems in the petroleum industry, especially formation of solid deposits and stabilization of water-in-oil emulsions. Many studies have been conducted to characterize chemical structures of asphaltenes and assess their phase behavior in crude oil or in model-systems of asphaltenes extracted from oil or asphaltic residues
Quím. Nova. Publicado em: 2016-01
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36. Evolution of Complex Phases in Al-Fe-Si Systems
Phase transformations and composition of Al-Fe-Si, Al-Co-Si and Al-Ni-Si based rapidly quenched ribbons have been investigated. Different Al-Si based alloys with varying Si content and additions of third metallic element, namely Al80Si20, Al60Si40, Al75Fe5Si20, Al70Fe10Si20, Al75Co5Si20, Al70Co10Si20, Al75Ni5Si20, Al70Ni10Si20 were analyzed. Variation of pha
Mat. Res.. Publicado em: 17/11/2015