Ivanira Moreira - Academia.edu (original) (raw)

Papers by Ivanira Moreira

Water loss and sugar gain were modeling during the osmotic dehydration process of cylinders of ap... more Water loss and sugar gain were modeling during the osmotic dehydration process of cylinders of apple. The transfer of solute to the fruit and the water to the solution was based on Fick’s 2nd law generalized for simultaneous diffusion and solved by the ?nite element method using the software COMSOL Multiphysics 3.2. The main and cross diffusion coef?cients, the relationship between the mass transfer and mass conductivity coef?cients, as well, the Biot number were determined on the simulation with the implementation of the simplex optimization method through minimization of the percentage deviations. 1

Revista Virtual de Química, 2020

Resumo: O biodiesel possui baixa estabilidade oxidativa devido ao alto teor de ésteres insaturado... more Resumo: O biodiesel possui baixa estabilidade oxidativa devido ao alto teor de ésteres insaturados em sua composição, e sua degradação pode ocorrer devido à exposição ao ar, umidade, luz, calor, contaminação por microrganismos e presença de metais. Esta pesquisa tem como objetivo avaliar a influência de ligas de aço carbono, aço 1020 e amostra de tubulação industrial no armazenamento de biodiesel. A amostra de biodiesel em contato com a amostra de tubulação industrial apresentou menores valores do período de indução e, consequentemente, maiores constantes de velocidade, acelerando a degradação do biodiesel. O biodiesel em contato com o aço carbono e o aço 1020 apresentou menor degradação quando comparado à amostra de tubulação industrial. O biodiesel na presença da liga de aço carbono apresentou maior estabilidade oxidativa que a da amostra na presença de aço 1020. Algumas amostras apresentaram reações de oxidação complexas com desvios da linearidade descrita por Arrhenius. Biodiesel has low oxidative stability due to the high content of unsaturated esters in its composition. Its degradation can occur due to exposure to air, humidity, light, heat, contaminants and in the presence of metals. This study aims to evaluate the influence of alloys of carbon steel, steel 1020 and sample of industrial pipe in biodiesel storage. The sample of biodiesel in contact with the pipe presented lower values of the induction period, and consequently higher rate constants, accelerating the biodiesel degradation. The biodiesel in contact with carbon steel and steel 1020 showed a lower degradation when compared to the industrial pipe sample. The biodiesel in the presence of the carbon steel alloy presented higher oxidative stability than the sample in the presence of steel 1020. Some samples presented more complex oxidation reactions with deviations of the linearity described by Arrhenius.

Heat and Mass Transfer, 2020

Sodium chloride salt is used in the cheese salting because it promotes sensorial changes besides ... more Sodium chloride salt is used in the cheese salting because it promotes sensorial changes besides preserving the food, but in excess can cause hypertension. Therefore, it has been partially replaced by potassium chloride to not affect the sensory characteristics. In this work the mozzarella cheese was subjected to the diffusion of Na + and K + in brine by static and stirred immersion. The diffusion was modeled using the second law of Fick and simulated by the finite element method through the software COMSOL Multiphysics ® version 5.2. The main, cross coefficients and the relation between mass transfer coefficient and the mass conductivity were determined through simplex optimization, minimizing the percentage errors between the experimental and simulated concentrations, obtaining 3.79% ( w / v ) for NaCl and 5.66% (w/v) of KCl in static brine. In stirring brine, the errors obtained were 5.40% (w/v) for NaCl and 6.01% (w/v) for KCl. The resulting main diffusion coefficients were 1.12 × 10 −9 (m 2 /s) for NaCl and 0.91 × 10 −9 (m 2 /s) for KCl.

Semina: Ciências Exatas e Tecnológicas, 2018

O objetivo deste trabalho foi analisar o potencial de produção e otimização do extrato aquoso da ... more O objetivo deste trabalho foi analisar o potencial de produção e otimização do extrato aquoso da polpa da manga Palmer para a produção de etanol. Foi determinada a concentração de açúcares totais, na polpa pelo método do fenol sulfúrico e por cromatografia, sendo o valor obtido de açúcares totais de 83;33 gL-1 e 80,51 gL-1, respectivamente. Por meio de ensaios preliminares a 30°C, estabeleceu-se que o tempo de 10 horas apresentou o maior rendimento em etanol. Em seguida foi feita a fermentação, com 13 ensaios e duas repetições no ponto central, após, as amostras foram centrifugadas e o teor de álcool foi determinado. A otimização indicou uma formulação contendo 3,0 gL-1 de extrato de levedura, 8,0 gL-1 de levedura e 0,35 gL-1 de NH4H2PO4, para um teor de álcool de 34,4 gL-1 e rendimento de 88,27%. O caldo da cana-deaçúcar,diluído nas mesmas condições, também foi fermentado e passou pelos mesmos procedimentos, mas o resultado do teor de álcool foi de 35,68 gL-1 com rendimento de 70,7...

Biofuels, 2017

ABSTRACT In Brazil, biodiesel mainly consists of unsaturated fatty acid esters, which gives low o... more ABSTRACT In Brazil, biodiesel mainly consists of unsaturated fatty acid esters, which gives low oxidative stability. Therefore, natural antioxidants present themselves as an alternative to prevent oxidative deterioration due to the presence of phenolic compounds in their structure, capable of inhibiting free radicals by donating hydrogen atoms. Extracts of pepper, bacupari leaves, coffee leaves and sage were added to biodiesel B100 to verify the efficiency of antioxidant on the oxidation reaction of biodiesel, using as a parameter the comparative relative protection factor (RPF). Linearity deviations were observed in the graph of the logarithm of the rate constant as a function of the inverse of temperature, indicating that the activation energy varies at the different temperatures 110, 115, 120 and 125°C of the accelerated Rancimat test. The RPF analyzed by the simplex-centroid design proved to be a suitable parameter to verify the efficiency of natural antioxidants in the protection of the oxidation reaction, indicating an optimized mixture of 25% pepper, 60% coffee leaves and 15% sage.

Industrial Crops and Products, 2016

Soybean oil is currently the most widely used raw material for biodiesel production, but its main... more Soybean oil is currently the most widely used raw material for biodiesel production, but its main fatty acids are unsaturated, which makes the addition of antioxidants necessary. This study used alcoholic extracts of natural antioxidants rosemary, oregano and basil to evaluate the protection factor in biodiesel. The analysis of total phenolics content of the extracts showed that the highest values were found for rosemary extract, followed by oregano and basil. Thermogravimetric analysis indicated that the most stable extract was basil, followed by rosemary and oregano. After drying, the extracts were added to the B100 biodiesel and the samples were subjected to accelerate oxidative stability testing at temperatures of 110, 115, 120 and 125 • C following the experimental simplex-centroid design for mixtures. Through the relationship between the values of induction periods, from the different tests and control, the values of the relative protection factor (RPF) were determined. The multiresponse optimisation of predictive equations showed that the greatest value of the RPF was 3.73 for the test containing 50% of rosemary and 50% of oregano and the lowest was 2.94 for biodiesel containing only basil extract as an antioxidant.

Semina: Ciências Exatas e Tecnológicas, 2003

O presente trabalho teve como objetivo associar o ensino de alguns conceitos de química com o cot... more O presente trabalho teve como objetivo associar o ensino de alguns conceitos de química com o cotidiano dos alunos do Ensino Médio. O tema escolhido foi "detergente" porque este produto faz parte da vida diária das pessoas já há algumas décadas. Devido à presença de agente tensoativo, fosfatos e outras substâncias em sua composição, este produto tem provocado problemas ao ambiente. Partindo do tema motivador "detergente" e com a elaboração de um mapa conceitual foi possível abordar conceitos de ligações de hidrogênio, tensão superficial, forças de van der Waals, solubilidade, e ainda a questão da biodegradabilidade de produtos químicos no ambiente.

Semina: Ciências Exatas e Tecnológicas, 2010

A otimização do rendimento da reação de transesterificação de obtenção do biodiesel B100 foi estu... more A otimização do rendimento da reação de transesterificação de obtenção do biodiesel B100 foi estudada utilizando hidróxido de sódio, hidróxido de potássio, metóxido e etóxido de sódio como catalisadores. Foi aplicado o delineamento experimental de mistura simplex centróide e os resultados da otimização indicaram, com metanol, um rendimento de 97,61% quando se usa 30,77% de NaOH e 69,23% de metóxido de sódio e, com etanol, um rendimento de 89,32% quando se usa apenas o etóxido de sódio. A análise cromatográfica indicou que o biodiesel B100 obtido encontra-se dentro dos parâmetros estabelecidos pela Legislação Brasileira. Palavras-chave: Biodiesel. Transesterificação. Delineamento de mistura.

Food Science and Technology, 2012

The relationship of NaCl with problems of arterial hypertension has led to a reduction in the lev... more The relationship of NaCl with problems of arterial hypertension has led to a reduction in the levels of this salt in food production. KCl has been used as a partial substitute for NaCl since it cannot be completely substituted without affecting the acceptability of the end product. In this study, the diffusion that occurs during quail egg salting in static and stirred brine was simulated. The mathematical model used was based on a generalization of the Fick's 2nd law, and the COMSOL Multiphysics software was used to simulate the diffusion in the NaCl-KCl-water system. The deviations in the simulated data and experimental data were 2.50% for NaCl and 6.98% for KCl in static brine, while in the stirred brine they were 3.48% for NaCl and 4.72% for KCl. The simulation results presented good agreement with the experimental values and validated the predictive capacity of the model.

Fuel Processing Technology, 2014

Antioxidants are additives for the prevention of the degradation of biofuels. This study evaluate... more Antioxidants are additives for the prevention of the degradation of biofuels. This study evaluated the oxidative stability of B100 biodiesel from soybean oil with the addition of three synthetic antioxidants, butylhydroxyanisole (BHA), tertbutyl-hydroquinone (TBHQ) and butylated hydroxytoluene (BHT), either pure or mixed, according to the simplex-centroid mixture design. The obtained kinetic parameters indicated that the addition of the three pure antioxidants and a ternary mixture of the antioxidants resulted in an induction period that was greater than that of the control sample. Furthermore, based on the induction period (ip), the antioxidant BHT was the most efficient in preventing the oxidation of the B100 biodiesel used.

Acta Scientiarum. Technology, 2010

RESUMO. O uso de combustíveis alternativos para diminuir a emissão de poluentes na atmosfera é um... more RESUMO. O uso de combustíveis alternativos para diminuir a emissão de poluentes na atmosfera é uma tendência cada dia mais frequente, assim, faz-se necessária a investigação da eficiência destas misturas em proporções e condições diferentes. Ao diesel de petróleo, por força de legislação, estão sendo adicionados 3% de biodiesel. Os valores da massa específica e do ponto de fulgor das amostras de diesel comercial analisadas, contendo 2 e 3% de biodiesel, mostraramse dentro dos parâmetros estabelecidos pela legislação brasileira. Os valores do índice de peróxido do biodiesel B100 aumentaram com o tempo de estocagem e com a presença de luz. Apesar disso, pela análise do perfil cromatográfico, não se verificaram alterações profundas na composição química do diesel B100 nas diferentes condições de armazenamento. O presente trabalho teve como objetivo analisar os combustíveis fósseis em misturas com biodiesel para verificar a sua estabilidade e algumas propriedades físico-químicas. Palavras-chave: biocombustível, ponto de fulgor, índice de peróxido. ABSTRACT. Physical-chemical analysis of diesel blended with biodiesel. The use of alternative fuels to reduce pollutant emissions in the atmosphere is an increasingly frequent trend. Thus, it becomes necessary to research the efficiency of theses mixtures in various proportions and different conditions. To diesel oil, under the legislation, are being added 3% of biodiesel. The values of specific weight and the flashpoint of the samples of commercial diesel tested, containing 2 and 3% of biodiesel, were within the established parameters set by Brazilian legislation. The values of the peroxide index for B100 biodiesel increased with light and storage time. Nevertheless, analyzing the chromatographic profile, there were no considerable changes in the chemical composition of B100 diesel under different conditions of storage. The aim of this work was examine fossil fuels in blends with biodiesel to determine their stability as well as some physical-chemical properties.

Semina: Ciências Agrárias, 2010

Recebido para publicação 13/01/09 Aprovado em 02/06/10 Simulação da difusão multicomponente duran... more Recebido para publicação 13/01/09 Aprovado em 02/06/10 Simulação da difusão multicomponente durante a desidratação osmótica em maçã: determinação dos coeficientes de difusão pelo método simplex Simulation of the multicomponent diffusion during the osmotic dehydration of apple: determination of the diffusion coefficients by the simplex method

Química Nova, 2009

Recebido em 2/12/08; aceito em 15/4/09; publicado na web em 26/8/09 MODELING AND SIMULATION OF TH... more Recebido em 2/12/08; aceito em 15/4/09; publicado na web em 26/8/09 MODELING AND SIMULATION OF THE OSMOTIC DEHYDRATION PROCESS OF PINEAPPLE'S PIECES USING THE FINITE ELEMENT METHOD. Water loss and sugar gain were modelling during the osmotic dehydration process of pieces of pineaplle. The transfer of solute to the fruit and the water to the solution was based on Fick's 2nd law. The three dimensional model was solved by the finite element method with the usage of the software COMSOL Multiphysics 3.2. The main and cross diffusion coefficients and the Biot number were determined on the simulation and the deviation between the experimental and the simulated data were 4,28% to sucrose and 1,66 to the water.

Química Nova, 2010

THE SIMPLEX-CENTROID DESIGN APPLIED TO STUDY OF THE KINETICS OF THE OXIDATION OF B100 BIODIESEL I... more THE SIMPLEX-CENTROID DESIGN APPLIED TO STUDY OF THE KINETICS OF THE OXIDATION OF B100 BIODIESEL IN BLEND WITH SYNTHETIC ANTIOXIDANTS. Antioxidants are an alternative to prevent or slow the degradation of the biofuel. In this study, it was evaluated the oxidative stability of B100 biodiesel from soybean oil in the presence of three commercial synthetic antioxidants, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ), pure or blended, from the experimental design of simplex-centroid mixture. The reaction order and rate constant were also calculated for all tests. The treatment containing pure TBHQ proved to be the most effective, proven by design, the optimum mix obtained and the rate constant. Binary and ternary mixtures containing TBHQ also showed appreciable antioxidant effect.

Journal of Food Processing and Preservation, 2014

ABSTRACT The water loss and sugar gain modeling during the dehydration process is useful as a tec... more ABSTRACT The water loss and sugar gain modeling during the dehydration process is useful as a technique for predicting the operating conditions and the process time. The transfer of sucrose and fructooligosaccharides (FOSs) to melon and water to solution was modeled based on generalized form of Fick's second law for simultaneous diffusion and resolved by the finite element method using the software package COMSOL Multiphysics 3.2. The diffusion coefficients, the mass transfer coefficient and the Biot number were determined using the simplex optimization method by minimizing the percentage errors. The optimized main diffusion coefficients were 21.07 × 10−11 m2/s for sucrose, 15.60 × 10−11 m2/s for water and 8.96 × 10−11 m2/s for FOS. The simulation results exhibited good fits to the experimental values, which validates the model predictive ability. The developed system for diffusion simulating water and solutes will enable control and modulation of the sucrose and FOS content in melon pieces. Practical ApplicationsThe use of functional sugars in fruits generates a new range of food taking into account the growing consumer market of these products. The study of processes involved in osmotic dehydration, as well as mass transfer simulation and modeling, is a useful predictive tool for the food industry, for assisting in the process time optimization among other variables involved.

Fuel Processing Technology, 2011

Antioxidants are an alternative to prevent or retard biofuel degradation. This study assessed the... more Antioxidants are an alternative to prevent or retard biofuel degradation. This study assessed the oxidative stability of biodiesel B100, made from soybeans, in the presence of three synthetic antioxidants, butylhydroxyanisole (BHA), terbutylhydroquinone (TBHQ) and butylhydroxytoluene (BHT), pure or in mixture, from the simplex-centroid design. Results revealed that when the three oxidants were employed separately, as well as the ternary mixture, they presented induction period over 6 h, at 110°C, being in accordance with specifications of the norm EN1412. Besides that, depending on the temperature, the BHA, TBHQ and BHT oxidants act in different ways, highlighting that BHA and TBHQ presented higher efficiency in the prevention of the oxidative process of the biofuel B100.

Biofuels, 2019

Biodiesel is a renewable fuel derived from oilseeds or animal fats. Biofuel has low oxidative sta... more Biodiesel is a renewable fuel derived from oilseeds or animal fats. Biofuel has low oxidative stability due to the high content of esters of unsaturated fatty acids, which are easily oxidized when exposed to air, light, heat and metals. Antioxidants are added to biodiesel to retard the oxidative process, which can capture free radicals making them thermodynamically more stable. This study aims to analyze the oxidative stability of biodiesel in the presence of metallic alloys of carbon steel and 1020 steel with the presence of rosemary extract. The rosemary extract had a phenol content of of 25,579 mg EAG /g dry mass , acting as antioxidant. In the presence of the natural rosemary extract, the biodiesel samples with metallic alloys but without rosemary extract presented similar oxidative stability and physicochemical properties, but when the rosemary extract is present, the carbon steel alloy presented a considerable compatibility, reaching higher induction periods. The thermodynamic parameters of the biodiesel sample with carbon steel and natural rosemary extract showed a significant improvement with the addition of antioxidant.

Química Nova, 2014

SOLVENT EFFECTS ON EXTRACTION OF CHLOROGENIC ACIDS, CAFFEINE AND TRIGONELLINE IN Coffea arabica. ... more SOLVENT EFFECTS ON EXTRACTION OF CHLOROGENIC ACIDS, CAFFEINE AND TRIGONELLINE IN Coffea arabica. In this research work the effects of four solvents and their mixtures on the extraction of chlorogenic acids, caffeine and trigonelline in crude extracts of four coffee cultivars, traditional red bourbon, IAPAR59, IPR101 and IPR108 cultivars, were investigated by UV spectrophotometry and UV spectra obtained from RP-HPLC-DAD. The experimental results and the principal component analysis of UV spectra showed that the effect of solvent extraction of the metabolites does not depend on cultivars, because the spectral characteristics are similar, but the concentrations are different. The UV and UV-DAD spectra for four simplex centroid design mixtures were also similar but the concentrations of caffeine, trigonelline and the chlorogenic acids are different and depend on the solvent used in the extraction.