Principal Component Analysis Pca
Mostrando 1-12 de 298 artigos, teses e dissertações.
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1. Encoding of Luminescent Ink Markers Using Low-Level Data Fusion and Chemometrics
The identification and analysis of documentary fraud is always a challenge for forensic science. Document analysis has proven to be an important branch of forensics in elucidating the authenticity of documents. The development and incorporation of luminescent inks in authentic documents have proved to be an excellent security feature. This paper purposes the
Journal of the Brazilian Chemical Society. Publicado em: 2023
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2. Honey of Tetragonisca angustula from Southwestern Bahia: Influence of Seasonality on the Physicochemical Profile and Glioma Cell Inhibitory Effect
This study aims to analyze Tetragonisca angustula honey from southwestern Bahia for its physicochemical characteristics, phenolic compounds and glioma cell inhibitory effect, in samples from different periods of the year, dry (DP) and rainy (RP) period. The analyses showed that samples obtained in the DP and RP are statistically different for the physicochem
Journal of the Brazilian Chemical Society. Publicado em: 2023
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3. Quimiometria III - Revisitando a análise exploratória dos dados multivariados
In this work, three methods for pattern recognition, used as exploratory data analysis, are revisited. A brief review of principal component analysis, PCA, an unsupervised method, is provided. Next, the Mahalanobis distance and the confidence ellipses usually drawn around the scores samples are discussed. Fisher’s canonical variate analysis (a supervised m
Química Nova. Publicado em: 2022
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4. Use of a Portable Microscope Combined with a Smartphone to Determine the Authenticity of Brazilian Banknotes and National Driver’s Licenses
This study proposed using a portable microscope combined with a smartphone and application (PhotoMetrix® application) to evaluate the authenticity of Brazilian banknotes (R$50 and R$100) and national driver’s licenses (NDL) through image acquisition (Samsung S7) and chemometric treatment (principal component analysis (PCA)). Six regions of the banknote we
Journal of the Brazilian Chemical Society. Publicado em: 2022
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5. 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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6. In vivo and in vitro Volatile Constituents of the Flowers of Xylopia aromatica by HS-SPME/GC-MS
Xylopia aromatica (Lam.) Mart. (Annonaceae) is a typical species from the Brazilian cerrado that presents medicinal properties. The plant is distinguished by its large white flowers which produce a pleasant fragrance. X. aromatica is characterized by a wide range of medicinal application. These characteristics have motivated us to investigate the flowers vol
J. Braz. Chem. Soc.. Publicado em: 2021-05
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7. Physico-chemical and Nutraceutical Characterization of Selected Indigenous Guava (Psidium guajava L.) Cultivars
Abstract In order to ascertain physicochemical and nutraceutical attributes, indigenous guava (Psidium guajava L.) cultivars were comprehensively characterized. Eight cultivars namely Gola, Chota Gola, Surahi, Choti Surahi, Sufaida, Sdabahar, Lal Badshah and Karela were selected due to their climatic adaptability and commercial suitability. All the cultivars
Food Sci. Technol. Publicado em: 2021-03
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8. FATTY ACIDS ANALYSIS AND CHEMOTAXONOMIC CONSIDERATIONS OF MALVOIDEAE (MALVACEAE) SPECIES
Previous researches showed that fatty acids analysis might be a useful tool to support the taxonomic investigation. In this approach the fatty acids content of ten Malvoideae species was analyzed and its chemotaxonomic significance has been investigated. The aerial parts of the species were collected in the Northeast of Brazil and their fatty acid methyl est
Quím. Nova. Publicado em: 2021-02
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9. ATR-FTIR FOR CHARACTERIZING AND DIFFERENTIATING DRIED AND GROUND COFFEE CHERRY PULP OF DIFFERENT VARIETIES (Coffea Arabica L.)
ABSTRACT This study aimed to evaluate the performance of the infrared spectrum in the range of 4000−650 cm−1 for characterizing and differentiating dried and ground coffee cherry pulp of different varieties. The spectral data were subjected to first and second derivative treatments to perform the statistical analyses. Three varieties of coffee pulp were
Eng. Agríc.. Publicado em: 2021-02
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10. What to Expect for the New Year?
In this work, an analytical method for determination of Ba, Cu, Ni, V, and Zn, in medicinal herbs, through direct solid sample analysis by energy dispersive X-ray fluorescence spectrometry (EDXRF), was applied. Accuracy and precision (intra and inter day) of the analytical method were confirmed through analysis of certified reference material, tomato leaves
J. Braz. Chem. Soc.. Publicado em: 2021-01
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11. Direct Solid Sample Analysis of Medicinal Herbs for Determination of Ba, Cu, Ni, V and Zn by EDXRF
In this work, an analytical method for determination of Ba, Cu, Ni, V, and Zn, in medicinal herbs, through direct solid sample analysis by energy dispersive X-ray fluorescence spectrometry (EDXRF), was applied. Accuracy and precision (intra and inter day) of the analytical method were confirmed through analysis of certified reference material, tomato leaves
J. Braz. Chem. Soc.. Publicado em: 2021-01
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12. Evaluation of the Metabolic Profile of Arabica Coffee via NMR in Relation to the Time and Temperature of the Roasting Procedure
Coffee is one of the most popular and consumed products in the world, with high nutritional value and economic importance. However, some factors can change the organoleptic properties of a coffee species, without causing significant damage such as loss of important components. The present study evaluated the chemical profile, via nuclear magnetic resonance (
J. Braz. Chem. Soc.. Publicado em: 2021-01