Spectroscopy Nir
Mostrando 1-12 de 123 artigos, teses e dissertações.
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1. 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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2. 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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3. Pseudo-Univariate Calibration Based on NIR Spectroscopy in the Determination of Anthocyanins and Antioxidant Activity in Grape Juices
This work shows an alternative methodology based on a portable near-infrared (NIR) spectroscopy coupled to independent components analysis (ICA) in a pseudo-univariate calibration way to determine total anthocyanins (TA) concentration and antioxidant activity (AA) in whole grape juice. To this, the scores proportions more related to TA and AA were plotted ag
J. Braz. Chem. Soc.. Publicado em: 2021-05
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4. DIFERENCIAÇÃO CATIÔNICA DE BENTONITAS POR INFRAVERMELHO: UM ESTUDO DOS EFEITOS DA HIDRATAÇÃO DOS CÁTIONS TROCÁVEIS
In the bentonite industry, the most common procedure for quality control of the ore and the sodium activation process is the swelling method. However, this tool is restricted only to the differentiation of the sodium and non-sodium types, not considering the other cationic varieties. The objective of this study was to establish parameters for cationic differ
Quím. Nova. Publicado em: 2021-03
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5. AUTENTICAÇÃO DE ORÉGANO (Origanum vulgare L.) ORGÂNICO UTILIZANDO ESPECTROSCOPIA NIR E QUIMIOMETRIA
In recent years, the consumption of organic foods has considerably increased. The basic difference between organic and non-organic food products is the way in which they are produced and processed, and the authenticity of these products is a current trend in food science and analytical chemistry. In this sense, the objective of this work was to propose an an
Quím. Nova. Publicado em: 2020-12
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6. Omega-3 and Omega-6 Determination in Nile Tilapia’s Fillet Based on MicroNIR Spectroscopy and Multivariate Calibration
Tilapia (Oreochromis niloticus) is the most cultivated fish species in Brazil. Studies have shown that fish consumption is related to the prevention of cardiovascular diseases due to its high contents of polyunsaturated fatty acids, as omega-3 (n-3) and omega-6 (n-6). In this sense, a new method to determine omega-3 and omega-6 by near-infrared (NIR) spectro
J. Braz. Chem. Soc.. Publicado em: 2020-09
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7. Determination of Ethanol in Gel Hand Sanitizers Using Mid and Near Infrared Spectroscopy
Alcohol-based gel hand sanitizers became very popular during the COVID-19 (coronavirus disease 2019) pandemic. In Brazil, several irregular factories emerged requiring an efficient control by the police and regulatory agencies to guarantee product quality. This problem required a method to determine ethanol content, which led to the development of two method
J. Braz. Chem. Soc.. Publicado em: 2020-09
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8. DETERMINAÇÃO DA AUTENTICIDADE DE AMOSTRAS DE AZEITE COMERCIAIS APREENDIDAS NO ESTADO DO ESPÍRITO SANTO USANDO UM ESPECTROFOTÔMETRO PORTÁTIL NA REGIÃO DO NIR
Many instrumental techniques are used to monitor the quality of food products, highlighting near infrared spectroscopy (NIRS). In order to determine the authenticity of 60 commercial oil samples seized by the Espírito Santo state police, this work used a portable spectrometer in the NIR region associated with chemometric tools such as principal component an
Quím. Nova. Publicado em: 20/07/2020
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9. Prediction of quality parameters of food residues using NIR spectroscopy and PLS models based on proximate analysis
Abstract The real-time prediction in biorefinery industries has become essential. Models using partial least square regression (PLS) were developed to predict moisture, ash, volatile matter, fixed carbon and organic matter of coconut and coffee residues. In this study, 49 samples were collected and near infrared spectroscopy were applied to predict moisture,
Food Sci. Technol. Publicado em: 2020-06
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10. Near-Infrared Luminescence from Visible-Light-Sensitized Ruthenium(II)-Neodymium(III) Heterobimetallic Bridged Complexes Containing Alkoxy(silyl) Functional Groups
New infrared emitting d-f (ruthenium(II)-neodymium(III)) heterobimetallic complexes with alkoxy(silyl) functional groups have been prepared. Visible excitation evidenced energy transfer processes from the ruthenium(II) donor to neodymium(III) acceptors leading to infrared emission. Energy transfer rates (kEnT) and efficiency of energy transfer (ηEnT) are, r
J. Braz. Chem. Soc.. Publicado em: 2020-04
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11. ANÁLISE DE AMOSTRAS DE COMBUSTÍVEIS POR FOTOMETRIA, NIR PORTÁTIL E RMN DE 1H - UMA COMPARAÇÃO COM OS RESULTADOS ENCONTRADOS POR TÉCNICAS NORMATIZADAS
It has been recurring adulterations in fuels (such as gasoline, ethanol and diesel), being necessary the exploration of the use of more modern analytical techniques capable of controlling the quality of these fuels, since some regulated tests may be inefficient to detect the adulteration. Among them, it is highlighted proton nuclear magnetic resonance (1H NM
Quím. Nova. Publicado em: 2020-02
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12. Estimation of soil phosphorus availability via visible and near-infrared spectroscopy
ABSTRACT: Spectroscopic techniques have great potential to evaluate soil properties. However, there are still questions regarding the applicability of spectroscopy to analyze soil phosphorous (P) availability, especially in tropical soils with low nutrient contents. Therefore, this study evaluated the possibility to estimate P availability in soil and its po
Sci. agric. (Piracicaba, Braz.). Publicado em: 20/12/2019