Determination of flash point and cetane index in diesel using distillation curves and multivariate calibration

AbstractPartial least squares regression (PLS) was used to predict flash point and cetane index of diesel using distillation curves (ASTM-D86). The low RMSEP values obtained, compared with other chemometric models based on spectrometric methods described in literature, and high correlation coefficients between reference and predicted values showed that PLS was efficient to determine flash point and cetane index. The model built contains diesel samples of different compositions, thus revealing the variety of fuel in the Brazilian market. Furthermore, the proposed method has two advantages: low cost and easy implementation, as it applies the results of a routine test to evaluate the quality of diesel

Análise quimiométrica usando RMN de 13C como ferramenta para diferenciar duas espécies de Maytenus

Made available in DSpace on 2017-09-26T17:16:53Z (GMT). No. of bitstreams: 2 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) fernando_cesar_et_all.pdf: 389947 bytes, checksum: 1788622194f1ae8f27c340b1fc472b11 (MD5) Previous issue date: 25Universidade Federal de Minas Gerais. Belo Horizonte, MG, Brasil.Universidade do Estado de Minas Gerais. Belo Horizonte, MG, Brasil.Universidade Federal de São Paulo. São Paulo, SP, Brasil.Universidade Federal de Ouro Preto. Outo Preto, MG, Brasil.Universidade Federal de Ouro Preto. Outo Preto, MG, Brasil.Universidade Federal de Minas Gerais. Belo Horizonte, MG, Brasil.Maytenus robusta foi recentemente sinonimizada com Maytenus gonoclada devido à sobreposição de caracteres morfológicos utilizados na classificação botânica. O presente estudo investiga as diferenças químicas entre robusta Maytenus gonoclada e Maytenus robusta usando análise quimiométrica. Os dados de RMN de 13C de triterpenos pentacíclicos obtidos a partir dessas espécie foram avaliados por meio da Análise de Componentes Principais (PCA) e os friedelanes foram os metabólitos que mais contribuíram para as diferenças entre as duas espécies. Isso demonstra a análise quimiométrica como uma ferramenta importante para esclarecer a taxonomia de plantas semelhantes.Varronia curassavica Jacq (=Cordia verbenacea DC), Cordiaceae, is an American species widely spread from Argentina to Mexico. The species is tradicionally used for medicinal purposes in inflamatory diseases and is raw material for the first Brazilian phytotherapic (Acheflan®, Aché). Here, we aimed to describe the morphoanatomy of V. curassavica, searching useful features to its identification. The species has craspedodromous venation and wavy to dentate leaf margins. The epidermis has one layer of cells, with two types of glandular stalked trichomes, one possessing a globular head and other a kidney-shaped head, and two types of non-glandular trichomes, one of them possessing cystolith. Leaf blade is hypostomatic. Mesophyll is dorsiventral. Glandular trichomes are possibly the best feature to identify the species, since we can use it to distinguish V. curassavica from two other species of Varronia