Carbon
Mostrando 1-12 de 12091 artigos, teses e dissertações.
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1. Carbon Dots from Pilosocereus gounellei for Fluorimetric Determination of Tannin in Tea Using a Flow-Batch System
In this study, xiquexique (Pilosocereus gounellei) native endemic cactus from the Brazilian semiarid was used for the first time as a natural carbon source (“green precursor”) for the synthesis of highly fluorescent carbon dots (CDs). These CDs were successfully used to develop a fast, low-cost, eco-friendly fluorescence method for the determination of t
Journal of the Brazilian Chemical Society. Publicado em: 2023
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2. Minimal fresh gas flow sevoflurane anesthesia and postoperative acute kidney injury in on-pump cardiac surgery: a randomized comparative trial
Abstract Background Compound A is generated by sevoflurane when it reacts with carbon dioxide absorbers with strong bases at minimal fresh gas flow (FGF) and is nephrotoxic in animals. No conclusive data has shown increased risk in humans. The aim of this study was to investigate if minimal FGF promotes an increase in the incidence of acute kidney injury (A
Brazilian Journal of Anesthesiology. Publicado em: 2023
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3. Study of nanocomposites with carbon nanotubes and their tendency for carbon organization
Abstract The carbon derived from the thermal treatment of modified phenolic resins (PR) tends to organize into graphitic lamellae or turbostratic carbon and is commonly considered non-graphitizable. In this study, nanocomposites were synthesized with modified phenolic resin (Novolac) used as the matrix and oxidized multi-walled carbon nanotubes (NTox) in amo
Cerâmica. Publicado em: 2022
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4. Preparation of Silicon Oxycarbide (SiCO) Ceramics from Different Polymer Architectures and Assessment on the Performance as Electrodic Materials for Voltammetric Sensing of Antioxidant Phenolic Compounds
Silicon oxycarbide (SiCO) ceramics obtained from polymer pyrolysis and with varied carbon contents were prepared and evaluated as new electrodic materials for sensing of tert butylhydroquinone (TBHQ) and butylated hydroxyanisole (BHA) antioxidants. Three polymers were synthesized varying molecular architecture and aromatic carbon groups, followed by pyrolysi
Journal of the Brazilian Chemical Society. Publicado em: 2022
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5. Carbon and Nitrogen Stocks Under Different Land-Use in the Paraopeba River Basin-MG Before the Corrégo do Feijão Dam Burst
ABSTRACT Soil attributes can provide indicators for the management and conservation of natural and agrarian ecosystems. This study was carried out before the rupture of the Córrego do Feijão dam and aimed to evaluate and quantify the stocks of carbon, nitrogen and the C/N ratio in soils around the Paraopeba-MG river basin in five regions corresponding to t
Revista Ceres. Publicado em: 2022
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6. Recent Developments on Palladium-Catalyzed Carbonylation Reactions in Renewable Solvents
Palladium-catalyzed carbonylation reaction has surfaced as a robust tool for insertion of the carbonyl group into organic molecules, and in the last decades enormous progress has been made. Nowadays, a plethora of methodologies is available to synthesize all kinds of carbonyl compounds. However, the focus has shifted during recent years to address rising con
Journal of the Brazilian Chemical Society. Publicado em: 2022
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7. WSOC and Its Relationship with BC, Levoglucosan and Transition Metals in the PM2.5 of an Urban Area in the Amazon
Water-soluble organic carbon (WSOC) makes up a large mass fraction of the organic carbon in the aerosol and can influence important cloud processes in the atmosphere. The capacity of WSOC to form metallic complexes with transition metals is well known; however, its influence on the aerosol of urban areas in the Amazon region is not very well known. In this s
Journal of the Brazilian Chemical Society. Publicado em: 2022
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8. Production of nanostructured crystalline composite using residual ashes from flocculated sludge burning process in a poultry slaughterhouse wastewater treatment system
Abstract Nanostructured crystalline composite (activated carbon) was synthesized from residual ashes of the burning process of the sludge generated in the flotation step of a poultry slaughterhouse and was used for Allura red dye adsorption. The ashes were chemically activated using two types of reagents, H2O2 and H3PO4, and the structure, morphology, and su
Cerâmica. Publicado em: 2022
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9. Role of the reducing agent in tungsten extraction by chlorination with chlorine from an ore enriched by physical means
Abstract The effect of three reducing agents (sulphur dioxide, pyrite and carbon) on tungsten extraction from a scheelite-wolframite concentrate with chlorine gas was assessed. A low-grade ore (0.9% w/w WO3) was collected in the San Martín department, San Luis Province, Argentina, and subsequently enriched by physical means (65.73% w/w WO3). The minerals id
REM - International Engineering Journal. Publicado em: 2022
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10. RING CURRENT IN ANTHRACENE AND PHENANTHRENE: CORRECTION TO HÜCKEL PARAMETERS
Excessive degeneracy in the ground state of the π-electron energy levels of anthracene was removed using the Hückel method by correcting the Coulomb integral of the four central carbon atoms. A further correction to the resonance integral was proposed based on the ring-current model, which describes the π-ring current flow along the molecule’s perimeter
Química Nova. Publicado em: 2022
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11. Spectrofluorimetric Determination of Hydrochlorothiazide by a Carbon Dots-Based Probe via Inner Filtering Effect and Resonance Rayleigh Scattering
Synthesis of carbon dots (CDs) from natural resources not only enables green synthesis and production of environmentally friendly materials, but also provides a cost-effective probe as a fluorescence nanosensor. The proposed sensor introduces a unique one-pot hydrothermal CDs synthesis from alfalfa leaves, which is promising for sensing hydrochlorothiazide (
Journal of the Brazilian Chemical Society. Publicado em: 2022
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12. Limits of carbon pricing in a climate-changing world
Resumo Nas duas últimas décadas, consolidou-se um consenso normativo de resposta ao problema das mudanças climáticas por meio de instrumentos econômicos. O artigo relaciona o consenso em torno da precificação do carbono à racionalidade neoliberal e argumenta que esta ênfase na economia ajuda a explicar os resultados limitados da precificação de ca
Revista Direito e Práxis. Publicado em: 2022