Douglas Queiroz Santos - Academia.edu (original) (raw)

Papers by Douglas Queiroz Santos

Planta Daninha, 2007

A alelopatia é um dos fenômenos pouco estudados no Cerrado. Trata-se de uma ocorrência natural, r... more A alelopatia é um dos fenômenos pouco estudados no Cerrado. Trata-se de uma ocorrência natural, resultante da liberação de substâncias capazes de estimular ou inibir o desenvolvimento de outras plantas. Objetivou-se neste trabalho avaliar a ação alelopática de extratos da sucupira-branca (Pterodon emarginatus) sobre a germinação e o desenvolvimento da raiz e parte aérea do capim-colonião (Panicum maximum). Bioensaios de germinação realizados em placas de Petri comprovaram que o extrato metanólico do tronco dessa planta, a 150 ppm, inibiu 83% do desenvolvimento da raiz, 75% da parte aérea e 30% da germinação de sementes de capim-colonião. Em casa de vegetação, os resultados de inibição foram de 83% para a parte aérea, 80% para a raiz e 63% para a germinação, mas somente na concentração de 400 ppm. Frações do extrato metanólico bruto obtidas por cromatografia de coluna cromatográfica não reproduziram os resultados de inibição obtidos inicialmente. A fração mais ativa (diclorometano/cl...

Adulterants in biodiesel/diesel blends modifies its physical and chemical properties. In this wor... more Adulterants in biodiesel/diesel blends modifies its physical and chemical properties. In this work, Fourier Transform Mid-Infrared spectrometry (FT-MIR) and multivariate control charts based on Net Analyte Signal (NAS) were used to monitor the quality of Crambe methyl biodiesel in relation to the biodiesel content and the presence of adulterants. The calibration model was constructed from the decomposition of the instrumental signals of the calibration samples into three vectors: NAS, interference and residual. From these vectors, three control charts were built: (i) NAS chart to monitor the analyte of interest (Crambe methyl biodiesel); (ii) Interference chart to monitor the data matrix (all components in diesel without the analyte of interest); and (iii) Residual chart to monitor any non-systematic variations. To validate the calibration model, other groups of B10, BX and B10 samples adulterated by direct addition of soybean oil and used fry oil in the range of 4.85-30.13% (v/v) w...

The production of methyl esters via transesterification reaction of triacylglycerides of macaúba ... more The production of methyl esters via transesterification reaction of triacylglycerides of macaúba and palm kernel oils, with subsequent atmospheric distillation and separation of six fractions of the produced biodiesel, corresponding to 60% of its initial volume, is reported. The composition in esters of the produced biodiesel, its fractions and remaining residue of the distillation was determined by gas chromatography. This analytical procedure has allowed to monitor the content in esters for each distilled fraction. The fractions richer in C8:0, C10:0, C12:0, C14:0 is intended to be used as an aviation fuel, in blends with the Jet-A1 biokerosene. The residues from the distillation with higher molecular weights than those corresponding to esters C16:0, C18:0 and C18:1 are destined to other combustion engines as any conventional biodiesel. For the biodiesel obtained from the macaúba kernel, this distillation led to an enrichment from 45.86% to up to 74.35% in the C12:0 ester. For the...

Brazilian Journal of Thermal Analysis, 2015

Este trabalho apresenta a caracterizacao fisico-quimica e analise termica para diferentes tipos d... more Este trabalho apresenta a caracterizacao fisico-quimica e analise termica para diferentes tipos de biodiesel metilicos obtidos a partir de oleaginosas: colza (BMCL), girassol (BMSF), soja (BMSO), milho (BMCR), algodao (BMCT), Jatropha curcas L. (BMJC) e oleo residual de frituras (BMRE). Os resultados termoanaliticos apresentaram que os biodieseis tem desempenho satisfatorio em relacao a norma ASTM D 6751 que estabelece 90% de volatilizacao e/ou recuperacao do biocombustivel a 360 ° C de temperatura de aquecimento.

E ste trabalho teve por objetivo a aplicacao de figuras de merito multivariadas para validar meto... more E ste trabalho teve por objetivo a aplicacao de figuras de merito multivariadas para validar metodologias de analises de controle de qualidade de biocombustiveis empregando espectroscopia no infravermelho medio (MIR) e calibracao multivariada por quadrados minimos parciais (PLS). Os modelos PLS foram construidos para quantificar metanol em biodiesel metilico produzido a partir de oleo de fritura usado (B100), na faixa de concentracao de 0,14 a 1,00% (m/m) e quantificar oleo de fritura usado em mistura B5 (5% de biodiesel e 95% de diesel) na faixa de 1,00 a 30,00% (m/m). As metodologias foram validadas atraves das figuras de merito multivariadas como exatidao, linearidade, seletividade, sensibilidade, sensibilidade analitica, razao sinal-ruido, teste para erro sistematico, limites de deteccao e quantificacao, intervalo de confianca e elipse de confianca. Os resultados obtidos foram satisfatorios, com valores de erro quadratico medio de previsao (RMSEP) abaixo de 0,17% (m/m) e erro me...

O uso indiscriminado e excessivo e resultado de uma visao equivocada do processo agricola, que ge... more O uso indiscriminado e excessivo e resultado de uma visao equivocada do processo agricola, que gera, como consequencia, a crescente resistencia de pragas, microrganismos fitopatogenicos e ervas daninhas aos produtos sinteticos, aumentando a dependencia de insumos quimicos por parte de produtores e impulsionando a industria a descoberta e formulacao de novos principios ativos, formando um ciclo vicioso de alto custo economico e ambiental, contaminacao e degradacao de solos e aguas, desertificacao, salinizacao, reducao da biodiversidade e desequilibrios ecologicos, levando finalmente a insustentabilidade dos sistemas de producao agricola. A planta daninha Brachiaria decumbes – capim-braquiaria – e uma especie graminea monocotiledonea da familia Poaceae, forrageira para producao pastoril amplamente disseminada e utilizada e no Brasil. O objetivo deste trabalho foi realizar avaliacao fitotoxica do extrato em diclorometano de raiz de capim braquiaria nas concentracoes de 0, 50, 100, 150 ...

Ciências da Saúde: uma abordagem holística

Saúde e Pesquisa

Este estudo teve como objetivo analisar os teores de flúor na água de abastecimento público do mu... more Este estudo teve como objetivo analisar os teores de flúor na água de abastecimento público do município de Uberlândia (MG) e, adicionalmente, comparar os valores encontrados com os dados do controle operacional e de um laboratório de referência. Durante seis meses coletaram-se 126 amostras, as quais foram analisadas pela técnica eletrométrica, inicialmente na Universidade Federal de Uberlândia e depois pelo laboratório de referência. Por meio do teste Generalized Estimating Equations, os dados foram comparados entre si e com os de controle operacional. Observou-se diferença estatística entre os laboratórios, entre os momentos avaliados e na interação entre laboratório e tempo. Mesmo com variabilidade entre os resultados, pôde-se concluir que o flúor está presente na água de abastecimento de Uberlândia com teores dentro dos padrões recomendados pelo Centro Colaborador do Ministério da Saúde em Vigilância da Saúde Bucal quanto à concentração de fluoretos e que a população tem sido as...

Analytical Letters

Abstract A methodology was developed to monitor the adulteration of the B10 blend of diesel and c... more Abstract A methodology was developed to monitor the adulteration of the B10 blend of diesel and crambe biodiesel using proton nuclear magnetic resonance (1H NMR) spectroscopy combined with data driven soft independent modeling of class analogy (DD-SIMCA) model. The training was performed only with samples of the target class (B10) while the validation was performed with a test set consisting of new samples of the target class (B10) and samples of B10 adulterated with crambe oil, used frying oil, and residual automotive lubricating oil. The efficiency of this methodology was characterized based on the sensitivity parameters for the training set and specificity for the test set, in which a value of 1 was obtained for both parameters. This sensitivity value for the training set indicates that no target class samples were classified as extreme or outliers. The specificity for the test set shows that all samples in the test set were correctly classified into their respective classes, demonstrating the high efficiency of the DD-SIMCA model in monitoring adulterants in B10 mixture of diesel and crambe biodiesel. The DD-SIMCA model is simpler to construct than the multivariate control chart and the partial least squares discriminant analysis (PLS-DA) because its development does not require prior information about the adulterants. The excellent obtained results in the application of this model suggest that this analytical methodology is efficient, feasible and suitable for use by inspection agencies to characterize the quality of this fuel.

Ambiente e Agua - An Interdisciplinary Journal of Applied Science

The surveillance of the concentration of fluoride in the public water supply aims to ensure the b... more The surveillance of the concentration of fluoride in the public water supply aims to ensure the balance between the benefits (carie prevention) and risk (dental fluorosis) of water fluoridation programs. The aim of this study was to check the accuracy of two analytical methods for monitoring the concentration of fluoride in the public water supply of a Brazilian city. The STROBE checklist was used to aid the conduction of this study and report the results. It was an analytical, observational, and prospective study using the water supply of Uberlândia, MG, Brazil. We collected 126 water samples at 21 sites for six consecutive months and analyzed them using the fluoride ion selective electrode (F-ISE) method and colorimetry with SPADNS. The statistical analysis was performed descriptively and then the ANOVA and Student t-test for paired samples were applied. The results showed that the F-ISE method had a lower coefficient of variation (12.3%) than the SPADNS method (57.4%). There was ...

Hygeia - Revista Brasileira de Geografia Médica e da Saúde

Este trabalho resulta de um Projeto "Mobilização comunitária e contribuições de agentes ambientai... more Este trabalho resulta de um Projeto "Mobilização comunitária e contribuições de agentes ambientais, enquanto estratégias de Promoção da Saúde com Escolas Municipais Rurais, Uberlândia (MG)", que propôs a mobilização social no monitoramento de vetores, por meio de ovitrampas, em parceria com o Instituto Federal de Educação, Ciência e Tecnologia

Biofuels

Abstract This work describes the use of adsorbents as starch from different sources (corn, potato... more Abstract This work describes the use of adsorbents as starch from different sources (corn, potato, cassava and rice), cellulose and Select 450® and compared to conventional wet washing with hot water in biodiesel purification, varying the time: 1, 2.5, 5, 7.5, 10, and 15 min in relation to weight/volume fixed at 5%. The adsorbents were characterised by SEM and BET analysis. For the acidity index, all purification processes resulted values in agreement with the specifications of the ANP in Brazil. The levels of free glycerin with the use of Select 450® (at all times, except 10 min), cassava starch (at all times, except 5 min), and cellulose (at all times, except 1 and 10 min) were also in agreement with ANP specifications. In relation to a combined alkalinity test, the best results were obtained with the use of Select 450® and potato and cassava starches. The turbidity was satisfactorily reduced with the use of potato (10 and 15 min), cassava (15 min), and rice (2.5 min) starches as well as Select 450® (at all times). In terms of water content, there was a decrease compared with crude biodiesel and biodiesel purified by conventional wet washing.

Talanta

A methodology was developed to monitor the content of crambe biodiesel in mixtures with conventio... more A methodology was developed to monitor the content of crambe biodiesel in mixtures with conventional diesel using hydrogen nuclear magnetic resonance (1H NMR) spectroscopy combined with the orthogonal projections on the latent structure-discrimination analysis (OPLS-DA). The efficiency of the developed OPLS-DA model was analyzed based on the criteria of true response statistics: false positive and false negative rate, sensitivity, specificity, efficiency and Matthew's correlation coefficient, where the sensitivity (true positive rate) and specificity (true negative rate) were both equal to 1 and the false positive and false negative rates were both equal to 0, which means that all samples to be predicted as belonging to the diesel class of interest, B10 (containing 10% biodiesel and 90% pure diesel), were predicted in class 1, and all samples to be considered as belonging to the diesel class, not of interest, BX (biodiesel content less and greater than in B10), were predicted in class 0. These results showed 100% correct classification of the training and test set samples for B10 and BX, demonstrating a high efficiency of the OPLS-DA model in the monitoring of crambe methyl biodiesel content when mixed with diesel in various proportions. The excellent results in the application of this model suggest that this analytical methodology is feasible, efficient and suitable for use by inspection agencies to control the quality of this fuel.

Química Nova

ATMOSPHERIC DISTILLATION OF BIODIESEL FROM MACAÚBA OR PALMISTE OIL TO OBTAIN LIGHTER ESTER FRACTI... more ATMOSPHERIC DISTILLATION OF BIODIESEL FROM MACAÚBA OR PALMISTE OIL TO OBTAIN LIGHTER ESTER FRACTION TO BE USED AS AVIATION FUEL. The production of methyl esters via transesterification reaction of triacylglycerides of macaúba and palm kernel oils, with subsequent atmospheric distillation and separation of six fractions of the produced biodiesel, corresponding to 60% of its initial volume, is reported. The composition in esters of the produced biodiesel, its fractions and remaining residue of the distillation was determined by gas chromatography. This analytical procedure has allowed to monitor the content in esters for each distilled fraction. The fractions richer in C8:0, C10:0, C12:0, C14:0 is intended to be used as an aviation fuel, in blends with the Jet-A1 biokerosene. The residues from the distillation with higher molecular weights than those corresponding to esters C16:0, C18:0 and C18:1 are destined to other combustion engines as any conventional biodiesel. For the biodiesel obtained from the macaúba kernel, this distillation led to an enrichment from 45.86% to up to 74.35% in the C12:0 ester. For the palm kernel biodiesel, the corresponding enrichment was from 66.76% up to 82.96%. Through this simple distillation, it was thus possible to effectively enrich, in C8:0 to C14:0 esters, the initial crude biofuel, with an efficiency of 30% for the macaúba and 11.5% for the palmiste biodiesel.

Renewable Energy

Abstract Oil either from macauba (Acrocomia aculeate) and palm (Elaeis guineensis) fruit kernel w... more Abstract Oil either from macauba (Acrocomia aculeate) and palm (Elaeis guineensis) fruit kernel was transesterified with methanol through the classical reaction with homogeneous alkaline catalyst. The produced fatty acid methyl esters (FAME) were further fractionated via atmospheric distillation as a step to obtain enriched fractions in short-molecular chain esters, ranging from C8 to C14, in a perspective to be blended with the conventional mineral jet fuel (Jet A-1). In this report, such blends of light biodiesels with Jet A-1 kerosene are described for their density, distillation fractions according to the temperature, structure changes under thermal treatments, by thermogravimetry and differential calorimetry analyses, freezing point, flash point, and calorific value. The blends corresponding to 5, 10 and 20 vol% in enriched short-chain esters with kerosene revealed values well within the recommended limits by the ASTM D1655. Light biodiesels, which are rich in lauric acid (C12:0) methyl esters are suitable to be blended with the Jet A-1 kerosene up to at least 5 vol%. Those blends could produce virtually very similar fuels, regarding the main technical standard properties, to the conventional fossil kerosene for jet engines, particularly concerning the moisture content, the density, its behavior in distillation and the flash point.

Fuel

Abstract Two methodologies were developed to quantify and classify the content of cotton biodiese... more Abstract Two methodologies were developed to quantify and classify the content of cotton biodiesel in blends with diesel using medium infrared spectroscopy associated with partial least squares (PLS) and partial least squares discriminant analysis (PLS-DA). The PLS model, developed to determine the biodiesel content, was validated on the basis of some merit figures: selectivity, sensitivity, analytical sensitivity, limit of detection, limit of quantification and test for systematic error. The fit of this model was also evaluated using the correlation of current and predicted values of the calibration and prediction sets – a high correlation was observed, with correlation coefficient exceeding 0.99, and relatively low errors for the parameters. Qualitative monitoring was done using the PLS-DA model, whose efficiency was analyzed based on parameters of sensitivity and specificity. These parameters showed 100% correct classification in the samples used for calibration and prediction of biodiesel content in the Brazilian B10 fuel for diesel engines. The good results for application of the two models suggest that these analytical methodologies are feasible and efficient and can be used by inspection bodies for quantitative and qualitative control of this fuel. In addition, these methodologies are quick, of low cost and allow in-situ analysis with portable equipment.

Analytical Letters

Abstract The use of mid-infrared spectrometry with horizontal attenuated total reflectance and Fo... more Abstract The use of mid-infrared spectrometry with horizontal attenuated total reflectance and Fourier transform, along with methods of variable selection by intervals, that is, interval partial least-squares (iPLS), backward interval partial least-squares (biPLS), and synergy interval partial least-squares (siPLS), were evaluated in order to quantify the Jatropha methyl biodiesel content in mixtures with diesel in the range from 0.25 to 30.00% (v/v). The spectral data were obtained in quintuplicate and corrected using the baseline technique. The constructed variable selection models were compared with the global partial least-squares (PLS) model by applying the F test to the root mean square error of prediction (RMSEP) value. The model with the best predictive capacity was iPLS24 (i.e., dividing the full spectrum into 24 equidistant intervals) constructed in the region from 650 to 750 cm−1 with 101 variables. The parameters obtained were the root mean square error of calibration (RMSEC) of 0.22%, the root mean square error of cross-validation (RMSECV) of 0.25%, RMSEP of 0.24%, limit of detection (LD) of 0.40% (v/v) and limit of quantification (LQ) of 0.13% (v/v). Therefore, the interval variable selection method was efficient in obtaining a spectral region that provided better predictive capacity than the global PLS model. In addition, with the selection of a smaller number of variables, it is possible to build portable equipment at a lower cost for use by fuel quality control agencies.

Planta Daninha, 2007

A alelopatia é um dos fenômenos pouco estudados no Cerrado. Trata-se de uma ocorrência natural, r... more A alelopatia é um dos fenômenos pouco estudados no Cerrado. Trata-se de uma ocorrência natural, resultante da liberação de substâncias capazes de estimular ou inibir o desenvolvimento de outras plantas. Objetivou-se neste trabalho avaliar a ação alelopática de extratos da sucupira-branca (Pterodon emarginatus) sobre a germinação e o desenvolvimento da raiz e parte aérea do capim-colonião (Panicum maximum). Bioensaios de germinação realizados em placas de Petri comprovaram que o extrato metanólico do tronco dessa planta, a 150 ppm, inibiu 83% do desenvolvimento da raiz, 75% da parte aérea e 30% da germinação de sementes de capim-colonião. Em casa de vegetação, os resultados de inibição foram de 83% para a parte aérea, 80% para a raiz e 63% para a germinação, mas somente na concentração de 400 ppm. Frações do extrato metanólico bruto obtidas por cromatografia de coluna cromatográfica não reproduziram os resultados de inibição obtidos inicialmente. A fração mais ativa (diclorometano/cl...

Adulterants in biodiesel/diesel blends modifies its physical and chemical properties. In this wor... more Adulterants in biodiesel/diesel blends modifies its physical and chemical properties. In this work, Fourier Transform Mid-Infrared spectrometry (FT-MIR) and multivariate control charts based on Net Analyte Signal (NAS) were used to monitor the quality of Crambe methyl biodiesel in relation to the biodiesel content and the presence of adulterants. The calibration model was constructed from the decomposition of the instrumental signals of the calibration samples into three vectors: NAS, interference and residual. From these vectors, three control charts were built: (i) NAS chart to monitor the analyte of interest (Crambe methyl biodiesel); (ii) Interference chart to monitor the data matrix (all components in diesel without the analyte of interest); and (iii) Residual chart to monitor any non-systematic variations. To validate the calibration model, other groups of B10, BX and B10 samples adulterated by direct addition of soybean oil and used fry oil in the range of 4.85-30.13% (v/v) w...

The production of methyl esters via transesterification reaction of triacylglycerides of macaúba ... more The production of methyl esters via transesterification reaction of triacylglycerides of macaúba and palm kernel oils, with subsequent atmospheric distillation and separation of six fractions of the produced biodiesel, corresponding to 60% of its initial volume, is reported. The composition in esters of the produced biodiesel, its fractions and remaining residue of the distillation was determined by gas chromatography. This analytical procedure has allowed to monitor the content in esters for each distilled fraction. The fractions richer in C8:0, C10:0, C12:0, C14:0 is intended to be used as an aviation fuel, in blends with the Jet-A1 biokerosene. The residues from the distillation with higher molecular weights than those corresponding to esters C16:0, C18:0 and C18:1 are destined to other combustion engines as any conventional biodiesel. For the biodiesel obtained from the macaúba kernel, this distillation led to an enrichment from 45.86% to up to 74.35% in the C12:0 ester. For the...

Brazilian Journal of Thermal Analysis, 2015

Este trabalho apresenta a caracterizacao fisico-quimica e analise termica para diferentes tipos d... more Este trabalho apresenta a caracterizacao fisico-quimica e analise termica para diferentes tipos de biodiesel metilicos obtidos a partir de oleaginosas: colza (BMCL), girassol (BMSF), soja (BMSO), milho (BMCR), algodao (BMCT), Jatropha curcas L. (BMJC) e oleo residual de frituras (BMRE). Os resultados termoanaliticos apresentaram que os biodieseis tem desempenho satisfatorio em relacao a norma ASTM D 6751 que estabelece 90% de volatilizacao e/ou recuperacao do biocombustivel a 360 ° C de temperatura de aquecimento.

E ste trabalho teve por objetivo a aplicacao de figuras de merito multivariadas para validar meto... more E ste trabalho teve por objetivo a aplicacao de figuras de merito multivariadas para validar metodologias de analises de controle de qualidade de biocombustiveis empregando espectroscopia no infravermelho medio (MIR) e calibracao multivariada por quadrados minimos parciais (PLS). Os modelos PLS foram construidos para quantificar metanol em biodiesel metilico produzido a partir de oleo de fritura usado (B100), na faixa de concentracao de 0,14 a 1,00% (m/m) e quantificar oleo de fritura usado em mistura B5 (5% de biodiesel e 95% de diesel) na faixa de 1,00 a 30,00% (m/m). As metodologias foram validadas atraves das figuras de merito multivariadas como exatidao, linearidade, seletividade, sensibilidade, sensibilidade analitica, razao sinal-ruido, teste para erro sistematico, limites de deteccao e quantificacao, intervalo de confianca e elipse de confianca. Os resultados obtidos foram satisfatorios, com valores de erro quadratico medio de previsao (RMSEP) abaixo de 0,17% (m/m) e erro me...

O uso indiscriminado e excessivo e resultado de uma visao equivocada do processo agricola, que ge... more O uso indiscriminado e excessivo e resultado de uma visao equivocada do processo agricola, que gera, como consequencia, a crescente resistencia de pragas, microrganismos fitopatogenicos e ervas daninhas aos produtos sinteticos, aumentando a dependencia de insumos quimicos por parte de produtores e impulsionando a industria a descoberta e formulacao de novos principios ativos, formando um ciclo vicioso de alto custo economico e ambiental, contaminacao e degradacao de solos e aguas, desertificacao, salinizacao, reducao da biodiversidade e desequilibrios ecologicos, levando finalmente a insustentabilidade dos sistemas de producao agricola. A planta daninha Brachiaria decumbes – capim-braquiaria – e uma especie graminea monocotiledonea da familia Poaceae, forrageira para producao pastoril amplamente disseminada e utilizada e no Brasil. O objetivo deste trabalho foi realizar avaliacao fitotoxica do extrato em diclorometano de raiz de capim braquiaria nas concentracoes de 0, 50, 100, 150 ...

Ciências da Saúde: uma abordagem holística

Saúde e Pesquisa

Este estudo teve como objetivo analisar os teores de flúor na água de abastecimento público do mu... more Este estudo teve como objetivo analisar os teores de flúor na água de abastecimento público do município de Uberlândia (MG) e, adicionalmente, comparar os valores encontrados com os dados do controle operacional e de um laboratório de referência. Durante seis meses coletaram-se 126 amostras, as quais foram analisadas pela técnica eletrométrica, inicialmente na Universidade Federal de Uberlândia e depois pelo laboratório de referência. Por meio do teste Generalized Estimating Equations, os dados foram comparados entre si e com os de controle operacional. Observou-se diferença estatística entre os laboratórios, entre os momentos avaliados e na interação entre laboratório e tempo. Mesmo com variabilidade entre os resultados, pôde-se concluir que o flúor está presente na água de abastecimento de Uberlândia com teores dentro dos padrões recomendados pelo Centro Colaborador do Ministério da Saúde em Vigilância da Saúde Bucal quanto à concentração de fluoretos e que a população tem sido as...

Analytical Letters

Abstract A methodology was developed to monitor the adulteration of the B10 blend of diesel and c... more Abstract A methodology was developed to monitor the adulteration of the B10 blend of diesel and crambe biodiesel using proton nuclear magnetic resonance (1H NMR) spectroscopy combined with data driven soft independent modeling of class analogy (DD-SIMCA) model. The training was performed only with samples of the target class (B10) while the validation was performed with a test set consisting of new samples of the target class (B10) and samples of B10 adulterated with crambe oil, used frying oil, and residual automotive lubricating oil. The efficiency of this methodology was characterized based on the sensitivity parameters for the training set and specificity for the test set, in which a value of 1 was obtained for both parameters. This sensitivity value for the training set indicates that no target class samples were classified as extreme or outliers. The specificity for the test set shows that all samples in the test set were correctly classified into their respective classes, demonstrating the high efficiency of the DD-SIMCA model in monitoring adulterants in B10 mixture of diesel and crambe biodiesel. The DD-SIMCA model is simpler to construct than the multivariate control chart and the partial least squares discriminant analysis (PLS-DA) because its development does not require prior information about the adulterants. The excellent obtained results in the application of this model suggest that this analytical methodology is efficient, feasible and suitable for use by inspection agencies to characterize the quality of this fuel.

Ambiente e Agua - An Interdisciplinary Journal of Applied Science

The surveillance of the concentration of fluoride in the public water supply aims to ensure the b... more The surveillance of the concentration of fluoride in the public water supply aims to ensure the balance between the benefits (carie prevention) and risk (dental fluorosis) of water fluoridation programs. The aim of this study was to check the accuracy of two analytical methods for monitoring the concentration of fluoride in the public water supply of a Brazilian city. The STROBE checklist was used to aid the conduction of this study and report the results. It was an analytical, observational, and prospective study using the water supply of Uberlândia, MG, Brazil. We collected 126 water samples at 21 sites for six consecutive months and analyzed them using the fluoride ion selective electrode (F-ISE) method and colorimetry with SPADNS. The statistical analysis was performed descriptively and then the ANOVA and Student t-test for paired samples were applied. The results showed that the F-ISE method had a lower coefficient of variation (12.3%) than the SPADNS method (57.4%). There was ...

Hygeia - Revista Brasileira de Geografia Médica e da Saúde

Este trabalho resulta de um Projeto "Mobilização comunitária e contribuições de agentes ambientai... more Este trabalho resulta de um Projeto "Mobilização comunitária e contribuições de agentes ambientais, enquanto estratégias de Promoção da Saúde com Escolas Municipais Rurais, Uberlândia (MG)", que propôs a mobilização social no monitoramento de vetores, por meio de ovitrampas, em parceria com o Instituto Federal de Educação, Ciência e Tecnologia

Biofuels

Abstract This work describes the use of adsorbents as starch from different sources (corn, potato... more Abstract This work describes the use of adsorbents as starch from different sources (corn, potato, cassava and rice), cellulose and Select 450® and compared to conventional wet washing with hot water in biodiesel purification, varying the time: 1, 2.5, 5, 7.5, 10, and 15 min in relation to weight/volume fixed at 5%. The adsorbents were characterised by SEM and BET analysis. For the acidity index, all purification processes resulted values in agreement with the specifications of the ANP in Brazil. The levels of free glycerin with the use of Select 450® (at all times, except 10 min), cassava starch (at all times, except 5 min), and cellulose (at all times, except 1 and 10 min) were also in agreement with ANP specifications. In relation to a combined alkalinity test, the best results were obtained with the use of Select 450® and potato and cassava starches. The turbidity was satisfactorily reduced with the use of potato (10 and 15 min), cassava (15 min), and rice (2.5 min) starches as well as Select 450® (at all times). In terms of water content, there was a decrease compared with crude biodiesel and biodiesel purified by conventional wet washing.

Talanta

A methodology was developed to monitor the content of crambe biodiesel in mixtures with conventio... more A methodology was developed to monitor the content of crambe biodiesel in mixtures with conventional diesel using hydrogen nuclear magnetic resonance (1H NMR) spectroscopy combined with the orthogonal projections on the latent structure-discrimination analysis (OPLS-DA). The efficiency of the developed OPLS-DA model was analyzed based on the criteria of true response statistics: false positive and false negative rate, sensitivity, specificity, efficiency and Matthew's correlation coefficient, where the sensitivity (true positive rate) and specificity (true negative rate) were both equal to 1 and the false positive and false negative rates were both equal to 0, which means that all samples to be predicted as belonging to the diesel class of interest, B10 (containing 10% biodiesel and 90% pure diesel), were predicted in class 1, and all samples to be considered as belonging to the diesel class, not of interest, BX (biodiesel content less and greater than in B10), were predicted in class 0. These results showed 100% correct classification of the training and test set samples for B10 and BX, demonstrating a high efficiency of the OPLS-DA model in the monitoring of crambe methyl biodiesel content when mixed with diesel in various proportions. The excellent results in the application of this model suggest that this analytical methodology is feasible, efficient and suitable for use by inspection agencies to control the quality of this fuel.

Química Nova

ATMOSPHERIC DISTILLATION OF BIODIESEL FROM MACAÚBA OR PALMISTE OIL TO OBTAIN LIGHTER ESTER FRACTI... more ATMOSPHERIC DISTILLATION OF BIODIESEL FROM MACAÚBA OR PALMISTE OIL TO OBTAIN LIGHTER ESTER FRACTION TO BE USED AS AVIATION FUEL. The production of methyl esters via transesterification reaction of triacylglycerides of macaúba and palm kernel oils, with subsequent atmospheric distillation and separation of six fractions of the produced biodiesel, corresponding to 60% of its initial volume, is reported. The composition in esters of the produced biodiesel, its fractions and remaining residue of the distillation was determined by gas chromatography. This analytical procedure has allowed to monitor the content in esters for each distilled fraction. The fractions richer in C8:0, C10:0, C12:0, C14:0 is intended to be used as an aviation fuel, in blends with the Jet-A1 biokerosene. The residues from the distillation with higher molecular weights than those corresponding to esters C16:0, C18:0 and C18:1 are destined to other combustion engines as any conventional biodiesel. For the biodiesel obtained from the macaúba kernel, this distillation led to an enrichment from 45.86% to up to 74.35% in the C12:0 ester. For the palm kernel biodiesel, the corresponding enrichment was from 66.76% up to 82.96%. Through this simple distillation, it was thus possible to effectively enrich, in C8:0 to C14:0 esters, the initial crude biofuel, with an efficiency of 30% for the macaúba and 11.5% for the palmiste biodiesel.

Renewable Energy

Abstract Oil either from macauba (Acrocomia aculeate) and palm (Elaeis guineensis) fruit kernel w... more Abstract Oil either from macauba (Acrocomia aculeate) and palm (Elaeis guineensis) fruit kernel was transesterified with methanol through the classical reaction with homogeneous alkaline catalyst. The produced fatty acid methyl esters (FAME) were further fractionated via atmospheric distillation as a step to obtain enriched fractions in short-molecular chain esters, ranging from C8 to C14, in a perspective to be blended with the conventional mineral jet fuel (Jet A-1). In this report, such blends of light biodiesels with Jet A-1 kerosene are described for their density, distillation fractions according to the temperature, structure changes under thermal treatments, by thermogravimetry and differential calorimetry analyses, freezing point, flash point, and calorific value. The blends corresponding to 5, 10 and 20 vol% in enriched short-chain esters with kerosene revealed values well within the recommended limits by the ASTM D1655. Light biodiesels, which are rich in lauric acid (C12:0) methyl esters are suitable to be blended with the Jet A-1 kerosene up to at least 5 vol%. Those blends could produce virtually very similar fuels, regarding the main technical standard properties, to the conventional fossil kerosene for jet engines, particularly concerning the moisture content, the density, its behavior in distillation and the flash point.

Fuel

Abstract Two methodologies were developed to quantify and classify the content of cotton biodiese... more Abstract Two methodologies were developed to quantify and classify the content of cotton biodiesel in blends with diesel using medium infrared spectroscopy associated with partial least squares (PLS) and partial least squares discriminant analysis (PLS-DA). The PLS model, developed to determine the biodiesel content, was validated on the basis of some merit figures: selectivity, sensitivity, analytical sensitivity, limit of detection, limit of quantification and test for systematic error. The fit of this model was also evaluated using the correlation of current and predicted values of the calibration and prediction sets – a high correlation was observed, with correlation coefficient exceeding 0.99, and relatively low errors for the parameters. Qualitative monitoring was done using the PLS-DA model, whose efficiency was analyzed based on parameters of sensitivity and specificity. These parameters showed 100% correct classification in the samples used for calibration and prediction of biodiesel content in the Brazilian B10 fuel for diesel engines. The good results for application of the two models suggest that these analytical methodologies are feasible and efficient and can be used by inspection bodies for quantitative and qualitative control of this fuel. In addition, these methodologies are quick, of low cost and allow in-situ analysis with portable equipment.

Analytical Letters

Abstract The use of mid-infrared spectrometry with horizontal attenuated total reflectance and Fo... more Abstract The use of mid-infrared spectrometry with horizontal attenuated total reflectance and Fourier transform, along with methods of variable selection by intervals, that is, interval partial least-squares (iPLS), backward interval partial least-squares (biPLS), and synergy interval partial least-squares (siPLS), were evaluated in order to quantify the Jatropha methyl biodiesel content in mixtures with diesel in the range from 0.25 to 30.00% (v/v). The spectral data were obtained in quintuplicate and corrected using the baseline technique. The constructed variable selection models were compared with the global partial least-squares (PLS) model by applying the F test to the root mean square error of prediction (RMSEP) value. The model with the best predictive capacity was iPLS24 (i.e., dividing the full spectrum into 24 equidistant intervals) constructed in the region from 650 to 750 cm−1 with 101 variables. The parameters obtained were the root mean square error of calibration (RMSEC) of 0.22%, the root mean square error of cross-validation (RMSECV) of 0.25%, RMSEP of 0.24%, limit of detection (LD) of 0.40% (v/v) and limit of quantification (LQ) of 0.13% (v/v). Therefore, the interval variable selection method was efficient in obtaining a spectral region that provided better predictive capacity than the global PLS model. In addition, with the selection of a smaller number of variables, it is possible to build portable equipment at a lower cost for use by fuel quality control agencies.