Precipitation
Mostrando 1-12 de 3094 artigos, teses e dissertações.
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1. Bioactive SiO2-K2O-CaO-P2O5 glass-ceramic scaffold prepared using polyurethane foam template
Abstract A glass-ceramic in the SiO2-K2O-CaO-P2O5 quaternary system was prepared by substituting the Na2O component with K2O to avoid Na2Ca2Si3O9 formation upon thermal treatment since this phase decreases apatite formation kinetics on glass material. To form the glass-ceramic, a modified sol-gel method involving solution precipitation, followed by reagents
Cerâmica. Publicado em: 2023
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2. Influence of Refinery Asphalt Residue Addition on Flow: A Study Using Waxy Model-System
One of the main phenomena causing problems in the oil industry is the precipitation of waxes, which can crystallize and form deposits, clogging lines and reducing flows. Many studies have been conducted seeking to overcome this problem, mainly through application of chemical to increase flow. Some studies have shown that the asphaltenes present in crude oil
Journal of the Brazilian Chemical Society. Publicado em: 2023
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3. Efficient Encapsulation and Controlled Release of N,N-Diethyl-3-methylbenzamide (DEET) from Oil-in-Water Emulsions Stabilized by Cationic Nanocellulose and Silica Nanoparticles
Oil-in-water emulsions containing N,N-diethyl-3-methylbenzamide (DEET) were developed aiming to extend the sustained release of the active compound, by using two oppositely charged nanomaterials, namely silica nanoparticles (SiNP) and cationic cellulose nanofibrils (CCNF), as stabilizers, and a mixture of food-grade nonionic surfactants to avoid precipitatio
Journal of the Brazilian Chemical Society. Publicado em: 2023
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4. EFFECT OF REACTION CONDITIONS ON PARTICLE SIZE OF ZNO NANOPARTICLES VIA CONTROLLED PRECIPITATION METHOD AND IN-VITRO ANTIBACTERIAL CAPACITY
High-yield ZnO spheroidal nanoparticles with an average diameter around 23 nm (≈ 25% frequency) and 30 nm (≈ 28% frequency) were obtained by controlled semicontinuous precipitation at low temperatures. This synthesis was obtained from hydrozincite (Zn5(CO3)2(OH)6) as primary nanoparticles. The Zn5(CO3)2(OH)6 nanoparticles were synthesized by hydrolysis o
Química Nova. Publicado em: 2022
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5. New Attempts to Synthesize Layered Double Hydroxides Intercalated with SO42-/Cs+ Using Co-Precipitation and Exchange Reactions
Layered double hydroxides (LDHs) with the compositions (Cs+/NH4+)0.111[M2+0.667Al0.333(OH)2.0 (SO4)0.222] (M2+ = Mn, Zn) and basal distance of ca. 11 Å were obtained by co-precipitating Mn/Al and Zn/Al sulfate salts with aqueous NH3, using excess of Cs2SO4. [Mn0.667Al3+0.333(OH)2]Cl0.333.nH2O and [M2+0.667Al3+0.333(OH)2](NO3)0.333.nH2O (M2+ = Mn, Zn) were a
Journal of the Brazilian Chemical Society. Publicado em: 2022
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6. Spatial Clustering of Extreme Annual Precipitation in Uruguay
Resumo O objetivo principal deste trabalho é estudar a existência de padrões espaciais de precipitação máxima anual (através de observações diárias) no território do Uruguai e mostrar a aplicação de duas novas ferramentas estatísticas recentemente propostas. Na primeira etapa, serão estudadas as distribuições da precipitação máxima anual
Revista Brasileira de Meteorologia. Publicado em: 2022
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7. Influence of the Local Structure on the Photocatalytic Properties of Zinc Spinel Ferrite Nanoparticles
The correlation between iron distribution in octahedral or tetrahedral sites in synthetic magnetite and zinc spinel ferrites and their catalytic properties were investigated in this work. The zinc-doped nanomagnetites were prepared by co-precipitation method and annealed at 420 °C. X-ray diffraction, UV-Vis, X-ray absorption and 57Fe Mössbauer spectroscopi
Journal of the Brazilian Chemical Society. Publicado em: 2022
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8. Tuning the Photocatalytic Activity of Tin Oxide through Mechanical Surface Activation
Tin oxide (SnO2) nanoparticles were synthesized by the co-precipitation method and mechanically modified by high-energy ball milling. The experimental results demonstrate that the collision with zirconia balls produces slight changes in the crystalline, electronic, morphological, and surface properties of SnO2, which lead to an increase in the redox potentia
Journal of the Brazilian Chemical Society. Publicado em: 2022
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9. Preparation and performance of magnetic zirconium-iron oxide nanoparticles loaded on palygorskite in the adsorption of phosphate from water
Magnetic zirconium-iron oxide nanoparticles loaded on palygorskite as a low-cost adsorbent was produced by one-step co precipitation technique and its properties for phosphate adsorption were overall investigated. The Brunauer Emmett Teller (BET) specific surface area analysis, scanning electron microscopy (SEM), thermo gravimetric analysis (TGA), Fourier tr
Química Nova. Publicado em: 2022
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10. Effect of meteorological factors on first episode and recurrence of primary spontaneous pneumothorax
SUMMARY OBJECTIVE: In this study, we evaluated the clinical characteristics and seasonal distribution of patients with primary spontaneous pneumothorax and examined the relationships between meteorological factors and pneumothorax development overall and in terms of first episode and recurrence. METHODS: The hospital records of 168 pneumothorax patients tr
Revista da Associação Médica Brasileira. Publicado em: 2022
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11. Determinação de etil-glicuronídeo e etil-sulfato em sangue por UPLC-MS/MS: aplicação clínica em vítimas de trauma
We developed a UPLC-MS/MS method for the quantification of the ethanol metabolites ethyl-glucuronide (EtG) and ethyl-sulfate (EtS) in blood samples. Sample preparation was a protein precipitation with acetonitrile 0.1% formic acid containing internal standards (IS) 0.5 µg mL-1 EtG-D5 and EtS-D5. Chromatographic separation was performed in a fluoro-phenyl co
Química Nova. Publicado em: 2022
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12. A Captura-Apreensão de Animais Silvestres no Brasil: Relações com a Variabilidade Pluviométrica
Resumo Este estudo mostra um perfil da captura-apreensão de animais silvestres no Brasil, nas cinco regiões geográficas (Norte, Nordeste, Centro-Oeste, Sudeste e Sul). O objetivo foi identificar suas diferenças regionais, investigar suas variabilidades e relacionar suas características, com ênfase à variação da pluviometria das regiões. Os dados us
Revista Brasileira de Meteorologia. Publicado em: 2022