Spectrometer
Mostrando 1-12 de 443 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. Lipid Profile of Human Milk in Different Lactation Stages Submitted to Pasteurization, Lyophilization and Spray-Drying Processes
The objective of this study was to evaluate the effect of pasteurization, lyophilization and spray-drying on the lipid profile of donated human milk (DHM) at different lactation stages. Nine frozen samples of colostrum, transitional and raw mature human milk (HM) were collected from the Human Milk Bank (HMB) of the Hospital Universitário de Maringá (HUM).
Journal of the Brazilian Chemical Society. Publicado em: 2023
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3. Rapid Recognizing the Producing Area of a Tobacco Leaf Using Near-Infrared Technology and a Multi-Layer Extreme Learning Machine Algorithm
A novel recognition method was put forward to identify the producing areas of the flue-cured tobacco leaves rapidly and non-destructively by using a near-infrared (NIR) spectrometer and a multi-layer-extreme learning machine (ML-ELM) algorithm. In contrast to traditional linear discriminant analysis (LDA) and extreme learning machine (ELM) algorithms, the ac
Journal of the Brazilian Chemical Society. Publicado em: 2022
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4. Thermal characterization of soil-cement bricks using mining tailings
Abstract Soil-cement bricks are earth construction materials that have been gaining prominence due to their environmental advantages. The Brazilian Technical Standard NBR 8491 establishes physical and mechanical procedures to characterize these bricks. However, the thermal characterization is an important assessment, since it is related to the building’s t
REM - International Engineering Journal. Publicado em: 2022
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5. Quantification of Carbon Dioxide (CO2), Methane (CH4), and Nitrous Oxide (N2O) Using Near Infrared Spectroscopy and Multivariate Calibration in High Humidity Levels
In this work we developed a promising analytical method combining Fourier transform near-infrared (FT-NIR) spectroscopic technique and first-order multivariate calibration using partial least-squares (PLS) model to simultaneously quantify the main greenhouse gases (GHG’s): methane (CH4), carbon dioxide (CO2), nitrous oxide (N2O) and water vapor (H2O). The
Journal of the Brazilian Chemical Society. Publicado em: 2022
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6. Preparation of SAPO-34-Based Catalyst for Conversion of Fructose to 5-Hydroxymethylfurfural
Solid acid-catalyzed dehydration of fructose to produce 5-hydroxymethylfurfural (5-HMF) has been a hotspot in biomass conversion research in recent years. In this study, a novel SAPO-34-based catalyst was prepared by consecutive steps of titanium doping, sulfuric acid impregnation, and sulfonic acid functionalization. Characterization of the catalyst with X-
J. Braz. Chem. Soc.. Publicado em: 2021-08
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7. Development of Analytical Method for Determination of Inorganic Constituents in Powder Refreshment Using Dilute Mineral Acids and Detection by ICP OES
An analytical method for multi-elementary determination in powder refreshment, based on sample digestion using dilute mineral acids and detection by inductively plasma coupled optical emission spectrometry (ICP OES) is proposed. Chemometric tools, such as fractional factorial design and principal component analysis (PCA) and hierarchical cluster analysis (HC
J. Braz. Chem. Soc.. Publicado em: 2021-07
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8. Porosity of CHA Zeolite Driving the Formation of Polyaromatic Coke Species in the Methanol to Olefins Reaction
The pore size of the chabazite structure is exceptionally suitable for the methanol to olefins (MTO) reaction. The reaction has an induction period required for the formation of a hydrocarbon pool (HP), usually composed of aromatic compounds of different sizes. HP is alkylated by methanol and afterward cracked, leading to the formation of olefins. Despite th
J. Braz. Chem. Soc.. Publicado em: 2021-05
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9. Thermal and Catalytic Fast Pyrolysis of Oily Extracts of Microalgae: Production of Biokerosene
Three different microalgae species, Desmodesmus sp., Nannochloropsis oculata and Halamphora coffeaeformis were grown under controlled conditions. The resulting dry biomass was characterized by TG-DTA (thermogravimetry-differential thermal analysis) and extracted with three solvents having different polarities. The extracts gross mass yields varied from 2% us
J. Braz. Chem. Soc.. Publicado em: 2021-04
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10. Impacto do ENOS na Variabilidade da Coluna Total de Ozônio Sobre a Região Nordeste do Brasil - Parte 1: El Niño Canônico e Modoki
Resumo O objetivo deste trabalho é analisar a variação anual e os efeitos do modo de variabilidade atmosférica El Niño (Canônico e Modoki) na Coluna Total de Ozônio (CTO) sobre o Nordeste Brasileiro (NEB) entre 1997 e 2018 utilizando dados dos sensores Total Ozone Mapping Spectrometer (TOMS) e Ozone Monitoring Instrument (OMI). Foi constatada uma vari
Rev. bras. meteorol.. Publicado em: 2020-12
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11. Impacto do ENOS na Variabilidade da Coluna Total de Ozônio Sobre a Região Nordeste do Brasil - Parte 2: La Niña Canônico e Modoki
Resumo Este estudo apresenta a segunda etapa da avaliação espaço-temporal das tendências a longo prazo nos valores da Coluna Total de Ozônio (CTO) sobre o Nordeste Brasileiro (NEB) durante a atuação do modo de variabilidade atmosférica El Niño - Oscilação Sul (ENOS), com foco na fase La Niña (modalidades Canônica e Modoki). O objetivo é analisa
Rev. bras. meteorol.. Publicado em: 2020-12
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12. Synthesis of ZnO Nanoparticles by the Sol-Gel Protein Route: A Viable and Efficient Method for Photocatalytic Degradation of Methylene Blue and Ibuprofen
The photocatalytic degradation of methylene blue dye and ibuprofen drug was studied in the presence of zinc oxide, synthetized by the protein sol-gel route. The catalyst, calcined at 1000 ºC, presented a tendentious morphology to filaments characteristic of ZnO crystalline, characterized by X-ray diffraction (XRD) and confirmed by the presence of Zn energy
J. Braz. Chem. Soc.. Publicado em: 2020-08