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O ensino das Ciências Naturais abrange os componentes curriculares Física, Química e Biologia e, obviamente, todos integrados às demais disciplinas do currículo escolar. No entanto é possível observar grandes lacunas entre o Ensino de Química e o Ensino de Física, considerando que ambas são disciplinas que se complementam nos conceitos abordados, possuindo assuntos e conteúdos similares ou relacionados a um mesmo fenômeno e que, na maioria das vezes, são abordados com diferentes enfoques. Este trabalho mostra os resultados de uma proposta de sequência didática interdisciplinar entre Química e Física, desenvolvida dentro do viés da pesquisa-ação, onde a professora regente é a pesquisadora e responsável pela implementação da mesma, em um colégio estadual do Município de São Miguel do Iguaçu-PR, tendo como tema central os fenômenos ópticos, valendo-se das teorias da aprendizagem significativa, fazendo uso de atividades experimentais de natureza investigativa, na tentativa de desenvolver estratégias didáticas que possam proporcionar ao estudante uma visão integral e globalizada do tema estudado, bem como buscar meios para permitir ao mesmo protagonizar a própria aprendizagem. O desenrolar do trabalho indicou que as atividades experimentais associadas às discussões, elaboração de hipóteses e análise de dados, dentro de uma problematização e de caráter investigativo, amplia a abrangência conceitual, contextualizando, aproximando o conhecimento transmitido na escola com o cotidiano do estudante. more...

This study aimed to chemically characterize commercial Essentials oils and determine their thermal properties and their antimicrobial and antioxidant activities. Essential oils extracted from leaves of Rosemary, lemongrass, cloves, orange, Tahiti lemon and thyme were studied, with chemical characterization by gas chromatography/mass spectrometry, thermoanalytical characterization and antimicrobial (microdilution) and antioxidant (ferric reduction activities power - FRAP). The chemistry of the essential oils composition was consistent with literature data and justified their thermal behavior. Comparing the thermal stability between the studied essential oils results revealed the optimization of the da Tonset = 106.6to clove`s essential oils. The results of differentiated antimicrobial and antioxidant activity justified by factors that influence the biological functions of Essentials oils, such as the origin of the plant (climate conditions), forms of cultivation and harvesting of the raw material, parameters and extraction method. Thus, it emphasizes the importance of a Brazilian production of essentials to take advantage of the technological and analytical capacity of national research centers, to provide the market with traceable products with certified identity. El presente estúdio tuvo como objetivo más grande caracterizar quimicamente los aceites esenciales comerciales y determinar sus propiedades térmicas, actividad antimicrobiana y antioxidante. Los aceites esenciales de romero, limoncillo, clavo, naranja, limón-tahití y tomillo extraídos de las hojas. Los aceites se analizaron utilizando Cromatografía de gases acoplada a espectro de masas (GC-MS), caracterización termoanalítica y actividades antimicrobianas (por microdilución) y antioxidante a través del método de potencia de actividad reductora férrica (FRAP). La composición química de los aceites esenciales fue consistente con los datos estudiados en la literatura y justificó su comportamiento térmico. Comparando la estabilidad térmica entre los aceites esenciales estudiados, los resultados revelaron la optimización de la Tonset = 106,6 de aceite esencial de clavo. Los resultados de las actividades antimicrobiana y antioxidante se justificaron por factores que influyen en las funciones biológicas de los aceites esenciales como las condiciones climáticas del origen de la planta, formas de cultivar y cosechar la materia prima, parámetros y métodos de extracción. De esta manera, este trabajo tiene como fundamento prioritario enfatizar la importancia de una producción brasileña de aceites esenciales y aprovechar la capacidad tecnológica y analítica de los centros de investigación nacionales para abastecer el mercado brasileño productos trazables con identidad certificada. O presente estudo teve como objetivo caracterizar quimicamente óleos essenciais comerciais e determinar as suas propriedades térmicas, atividade antimicrobiana e antioxidante. Foram estudados os óleos essenciais de alecrim, capim-limão, cravo, laranja, limão – tahiti e tomilho extraído das folhas. Os óleos foram analisados por meio de Cromatografia Gasosa acoplada ao Espectro de Massas (CG-EM), caracterização termoanálitica e atividades antimicrobiana (por microdiluição) e antioxidante via método de poder de atividade de redução férrica (FRAP). A composição química dos óleos essenciais se mostrou consistente com dados estudados na literatura e justificou seu comportamento térmico. Comparando a estabilidade térmica entre os óleos essenciais estudados resultados revelaram a otimização da Tonset = 106,6 do óleo essencial de cravo. Resultados das atividades antimicrobiana e antioxidante foram justificados por fatores que influem nas funções biológicas dos óleos essenciais como as condições climáticas da origem da planta, formas de cultivo e colheita da matéria-prima, parâmetros e métodos de extração. Deste modo, este trabalho tem como fundamento prioritário enfatizar a importância de uma produção brasileira dos óleos essenciais e aproveitar a capacidade tecnológica e analítica dos centros de pesquisa nacionais para fornecer ao mercado brasileiro produtos rastreáveis e com identidade certificada. more...

Catalytic processes play an important role in the valorization of biomass for the production of biofuels. In this context, the effect of desilication of MOR zeolite (H-MOR-D) on the esterification of oleic acid as a model reaction for biomass conversion was investigated. Zeolite catalysts were characterized by BET, TG, NH3-TPD, XRD, XRF, FTIR and 27Al MAS NMR analysis and the results showed that the alkaline treatment caused a decrease in crystallinity and removal of sites with greater acid strength of the zeolite precursor. The conversion of oleic acid into methyl oleate catalyzed by H-MOR was less (44%) than that obtained by the treated zeolite H-MOR-D (70%), suggesting that the catalytic activity in the MOR structure does not depend only on the high density of strong acid sites. DFT calculations showed that, bulky molecules suffer molecular distortions within the confined voids, consequently the adsorption enthalpy is highly unstable limiting the formation of intermediates and thus contributing to the lower reaction rate observed experimentally in H-MOR zeolite. Desilication should be considered in projects for the synthesis of new catalysts type zeolite for the conversion of biomass crude or pre-treated, in which bulky molecules prevail. more...

The use of new natural antimicrobials has gained attention from the pharmaceutical and food industry, in addition to end consumers, as additive options to conventional antibiotics for resistant microorganisms and also as natural preservatives. Essential oils are secondary plant metabolites that protect plants against predators and pathogens. The aim of this study was to evaluate thermal properties of cinnamon essential oil (EO) and its antibacterial activity. Ten components were identified, with (E) - cinnamic acid (67.70%) being the major component. Cinnamon EO was thermally stable up to 106.6ºC (Tonset) and Tdec occurred at 178.5 °C and Toffset up to 216.0 °C. There was endothermic transition; enthalpy variation (∆H) and activation energy (Ea) was -531.6 KJ Kg-1 and -1.26 ± 0.03 J mol-1, respectively. Bacterial strains showed distinct resistance to tested antibiotics and variation in Minimum Inhibitory Concentration values ranging from 0.8 to 1.6 mg mL-1. Cinnamon EO initiated bactericidal effect against all bacteria tested after four hours of contact and Minimum Bactericide Concentration was 0.4 mg mL-1, exception for Bacillus cereus (0.8 mg mL-1). Analysis of cinnamon thermal properties EO showed its stable thermal performance up to 106.6 °C and broad spectrum, that may be an antimicrobial proposal. El uso de nuevos antimicrobianos naturales ha llamado la atención de la industria farmacéutica y alimentaria, además de los consumidores finales, como opciones aditivas a los antibióticos convencionales para microorganismos resistentes y también como conservantes naturales. Los aceites esenciales son metabolitos vegetales secundarios que protegen a las plantas contra depredadores y patógenos. El objetivo de este estudio fue evaluar las propiedades térmicas del aceite esencial (AE) de canela y su actividad antibacteriana. Se identificaron diez componentes, siendo (E) - ácido cinámico (67,70%) el componente mayoritario. El AE de canela fue térmicamente estable hasta 106,6ºC (Tonset) y Tdec se presentó a 178,5 °C y Toffset hasta 216,0 °C. Hubo transición endotérmica; la variación de entalpía (∆H) y energía de activación (Ea) fue de -531,6 KJ Kg-1 y -1,26 ± 0,03 J mol-1, respectivamente. Las cepas bacterianas mostraron una resistencia distinta a los antibióticos probados y una variación en los valores de Concentración Inhibitoria Mínima que van desde 0,8 a 1,6 mg mL-1. El AE de Canela inició efecto bactericida contra todas las bacterias probadas después de cuatro horas de contacto y la Concentración Mínima de Bactericida fue de 0.4 mg mL-1, a excepción de Bacillus cereus (0.8 mg mL-1). El análisis de las propiedades térmicas de la canela EO mostró su comportamiento térmico estable hasta 106,6 °C y de amplio espectro, lo que puede ser una propuesta antimicrobiana. O uso de novos antimicrobianos naturais tem ganhado atenção da indústria farmacêutica e alimentícia, além dos consumidores finais, como opções aditivas aos antibióticos convencionais para microrganismos resistentes e também como conservantes naturais. Os óleos essenciais são metabólitos secundários de plantas que protegem as plantas contra predadores e patógenos. O objetivo deste estudo foi avaliar as propriedades térmicas do óleo essencial de canela (OE) e sua atividade antibacteriana. Dez componentes foram identificados, sendo (E) - ácido cinâmico (67,70%) o componente majoritário. O OE de canela foi termicamente estável até 106,6ºC (Tonset) e o Tdec ocorreu a 178,5ºC e o Toffset até 216,0ºC. Houve transição endotérmica; a variação de entalpia (∆H) e energia de ativação (Ea) foi de -531,6 KJ Kg-1 e -1,26 ± 0,03 J mol-1, respectivamente. As cepas bacterianas apresentaram resistência distinta aos antibióticos testados e variação nos valores de Concentração Inibitória Mínima variando de 0,8 a 1,6 mg mL-1. O OE de canela iniciou efeito bactericida contra todas as bactérias testadas após quatro horas de contato e a Concentração Bactericida Mínima foi de 0,4 mg mL-1, exceto para Bacillus cereus (0,8 mg mL-1). A análise das propriedades térmicas do OE de canela mostrou seu desempenho térmico estável até 106,6 °C e amplo espectro, podendo ser uma proposta antimicrobiana. more...

The objective of this work was to produce thermoplastic starch (TPS) and poly (butylene co-terephthalate adipate) (PBAT) incorporated with free and microencapsulated oregano essential oil (OEO) by blown extrusion and compare their properties. The OEO was microencapsulated by spray drying using arabic gum and maltodextrin as wall materials. The films were characterized in terms of physical, optical, morphological, thermal and antioxidant properties, and the OEO diffusion coefficient was determined in different food simulants. Regarding water vapor permeability (2.04–2.05 × 10−7 g m−1 Pa−1 h−1) and water solubility (6.25–9.65%), no significant difference (p > 0.05) was observed. Morphological images revealed that films with OEO microparticles (FM) showed greater roughness that caused a reduction in tensile strength, Young's modulus and elongation. FM film showed better thermal stability, significant concentration of phenolic compounds (3.6 mg EGA gfilm−1) and antioxidant capacity, and higher diffusion coefficient in ethanol 10% (aqueous food simulant, 1.3109 × 10–11 cm2 s−1) and 95% (non-aqueous food simulant, 39.8623 × 10–11 cm2 s−1). The results demonstrate the use potential of microencapsulated OEO in the development of biodegradable antioxidant films for food applications. more...

Cement industries generate about 7% of global CO2 emissions. To reduce these emissions, this sector aims to improve energy efficiency reducing the clinker content in cement and carbon capture deployment. The CO2 captured in cementitious materials occurs due to the carbonation reaction. This study aims to evaluate the CO2 uptake capacity in rendering mortars produced with recycled construction and demolition waste (CDW) by natural carbonation. Mortars were produced by replacing sand for CDW at rates of 0; 25; 50; 75, and 100% were naturally carbonated in a laboratory environment. Specimens were submitted to the compression test, bulk density, and water absorption. The carbonation profile was determined by phenolphthalein spray test over time. The CO2 captured was evaluated by thermogravimetry. The kinetic model showed that the carbonation reaction occurs more quickly in mortars with a higher substitution content, which is related to the increase in the porosity of the system improving the diffusion processes of CO2, leading to an increase in the carbonation depth. In addition, as the replacement level of CDW increases, the water absorption increases in contrast with the diminishing of the bulk density. Up to 50% of replacement level, samples with CDW showed higher compressive strength than the other cases. Moreover, results showed that the cement mortars with 50 to 75% of sand replacement by CDW, presented the highest amount of CO2 captured at 69 days, leading to 85 kg of CO2 per m3 of mortar. The CO2 capturing through natural carbonation of rendering mortar can be considered as a compensatory strategy in the cycle of life assessment of these materials. more...

In this paper, it was suggested the use of green corn husk, which is a biomass from agro-industry, as an alternative source of energy through its pyrolysis. Green corn husk characterization was done through immediate and elemental analysis of its components: cellulose, hemicelluloses, and lignin. It was also measured its higher calorific value. The pyrolysis study of green corn husk was done by the isoconversion and the Master plots method. Thermogravimetric plots were obtained at heating rates of 5, 10, 15, and 20 °C min−1. The pyrolysis kinetics parameters were studied through the Flynn–Wall–Ozawa (FWO), Kissinger, and Friedman models. The Master plots method was used to determine the pyrolysis reaction order. The results of the reaction energy activation were found to be in the range 105.21–157.46 kJ mol−1 by the FWO method, 150.50 kJ mol−1 by the Kissinger method, and ranged 120.66–163.81 kJ mol−1 by the Friedman method. The Master plots method showed a three-way-transport diffusional kinetics for the biomass de-volatilization process. The higher calorific value found for green corn husk was 16.14 MJ kg−1. The simulation showed correlation between the experimental data and the proposed model for conversion values up to 0.8. more...

The production of polymeric fibers by the electrospinning technique stands out as being simple, accessible, versatile and with potential use of polymer microfibers in many areas of science and technology. In this article, polymeric microfibers of PBAT/PLA and carbon nanotubes were obtained using a Fractional Factorial Design. The statistical results, the optical microscopy and scanning electron microscopy (SEM) showed that the addition of MWCNT’s had an influence in the diameter of the fibers (1.16 ± 0.22 µm), so that its incorporation decreased the value of the diameter, also they were more uniform and homogeneous. Besides, the MWCNT’s provided the fibers a better mechanical resistance, probably being inside the fibers, as well as showed in the analysis of wettability by contact angle. more...

This study refers to the development of hybrid briquettes using centrifuged sludge from the wastewater treatment of poultry and sawdust from furniture industry. The aim was to evaluate the performance of briquettes as a source of thermal energy, mitigating the risks of the current elimination and reducing the operational costs of their destination. To know the oxidizing characteristics of the briquettes and their mechanical resistance, superior calorific power, ash content, volatile materials, fixed carbon, and resistance to axial compression were evaluated. Thermogravimetric and differential exploratory calorimetry analyses were performed. Statistical treatments were carried out to verify the most significant factors to produce briquettes, the best proportions of the raw materials, and to evaluate whether there is interference from moisture and glue flour used as a binder. The best condition of the sludge-sawdust mixture was 15% and 85%, respectively, with 6.0% moisture. The best-case treatment had 23.82-MPa mechanical resistance, a calorific value of 17.20 MJ kg more...

In this work a method based on reversed-phase dispersive liquid-liquid microextraction (RP-DLLME) as sample preparation for the extraction and preconcentration of Na, K, Ca and Mg in biodiesel samples was developed. The analytes determination was performed by flame atomic absorption spectrometry (FAAS), operating in emission mode for Na and K and in absorption mode for Ca and Mg. The extraction/preconcentration step of the analytes was performed by using a mixture of dispersant and extractant solvents (isopropanol and HNO3, respectively) and the aqueous phase containing the analytes was separated by centrifugation. Some parameters such as sample mass, type and volume of dispersant and extractant solutions, HNO3 concentration (extraction solution), use of ultrasound, centrifugation time and temperature were evaluated. During the optimization of RP-DLLME, biodiesel samples were spiked with a multi-element biodiesel B100 (Conostan®) with final concentration of 1.0 μg g−1 of the analytes. Analytes determination was performed by FAAS using external calibration with aqueous reference solutions. The limits of quantification (LOQ) for Na, K, Ca and Mg were 0.04; 0.02; 0.05 and 0.08 µg kg respectively. The accuracy was evaluated by recovery tests, which ranged from 93.9% to 108.1%, with relative standard deviation lower than 3% for all analytes. Then, the proposed method was applied for analytes determination in five biodiesel samples produced from different raw materials. Comparing to conventional methods for elements determination in biodiesel (e.g., dilution with organic solvent, sample digestion, etc.), RP-DLLME combined to FAAS is simple, low cost, low reagents consumption and provides LOQs values significantly below compared to the limits established in the legislation for these elements in biodiesel. more...

Films based on cassava starch have been widely used for fruit coating; however, it is necessary to incorporate other polymers in order to improve mechanical properties, once starch only leads to highly hydrophilic films, compromising their application. In this way, a polymeric blend based on cassava starch, chitosan and gelatin was combined with a plasticizer to produce biodegradable films with satisfactory mechanical and barrier properties, in order to be used as fruit coating. The films were prepared by casting method and a statistical design of 23 was used to evaluate the effect of each polymer and what their combinations would influence over the final product. The formation of a physical blend was confirmed by FTIR. It showed low solubility, varying (10 ± 2) % a (23 ± 4) %, Opacity ranging from (1.06 ± 0.04) to (1.55 ± 0.13) AU x nm/mm, thickness from (0.20 ± 0.01) mm to (0.44 ± 0.03) mm and water vapor transmission rate ranging from 25 ± 0.2 to 30 ± 1.4 g s−1 m−2. Lower amounts of starch led to more flexible, less opaque and soluble films, while the combination of higher levels of starch and chitosan was responsible for lowering films water vapor transmission rate. Thus, the films showed interesting properties for fruit surface coating. more...

Residual oils and fats are promising renewable sources for the production of liquid fuels and the synthesis of various chemicals with significant life cycle and large-scale economic advantages over other biomass sources. Thus, oleic acid esterification was investigated on zeolites type FAU and sulfuric acid by kinetic, spectroscopic assessments and theoretical calculations using a hybrid ONIOM scheme. In the catalytic tests, the solid catalyst with the highest Si/Al (H-Y-80) ratio showed the highest catalytic activity for esterification (92% conversion) as compared to H-Y-5.2 (66% conversion), Na-Y (15% conversion) and homogeneous acid catalysis (89% conversion). The catalytic activity between different acid catalysts is discussed. It was observed that the acidity of the active sites and the hydrophobicity resulting from the Si/Al molar ratio influence the esterification conversion. Theoretical calcultations predicts that the voluminous confined space of the FAU zeolite perfectly accommodates the oleic acid molecule in the adsorption step (Eads = − 25.5 kJ mol−1) and the van der Waals interactions of the zeolite walls with the aliphatic chain help to accommodate the bulky molecule between the supercages. Experimental and theoretical results confirm that H-Y-80 zeolite applied in the esterification reaction can be an efficient catalyst in processes involving conversion of unsaturated fatty acids. more...

In this study, microparticles comprising L-alanyl-L-glutamine (AGP) were developed. A combination of pectin and Surelease® (ethylcellulose aqueous dispersion) was responsible for sustained AGP release properties in the gastrointestinal tract. A multiparameter optimization was conducted using a 23 factorial design. A broad array of formulation attributes were investigated (morphology, size, polydispersity, and entrapment efficiency) to identify suitable formulation candidates. Afterwards, two preparations (f7 and f8) varying in their pectin:Surelease® ratio were selected for further characterization (TG/DSC, XRD, FTIR, in vitro release and in vivo study). The factorial design revealed a strong influence of drying temperature on particle size and AGP entrapment efficiency. Thermal and spectroscopic analyses confirmed stability of the formulations at up to 200 °C as well as an effective encapsulation of the dipeptide. A small but not significant difference in the in vitro release profiles was found. However, in the in vivo test, formulation f8 presented a quicker effect of AGP in comparison to f7 in an animal model of insulin-induced hypoglycemia, suggesting that the higher concentration of the hydrophilic polymer pectin in f8 contributes to a faster release and bioavailability. Therefore, this study showed the possibility of encapsulating AGP using pectin and Surelease® with preserved activity of the dipeptide, and depending on the intended time and duration for action, other polymer ratios can be tested. more...

Polymeric aesthetic aligners were introduced in orthodontics as an innovative alternative to fixed appliances, however, their compositions and the thermal molding process may influence the biomechanical characteristics of these aligners. In this study four different clear aligner brands were used, ACE 035 Essix, C + Essix, Crystal 0.75 and Crystal 1.0, whose aim was to identify the thermal-processing influence on the mechanical and physicochemical properties of these materials, and to suggest a orthodontic sequence of wear for these appliances to achieve more effective treatment results. For the tensile tests the sample size calculation was based on probability distributions from the F test. The effect size used was 0.3, type 1 error of 0.05. Statistical Yield strength and Young's Modulus results were evaluated using the Shapiro-Wilk test. The groups were compared using the parametric test of analysis of variance, with Tukey post-test. Differences were statistically considered at the p 0.05. The Infrared spectroscopy analysis showed no changes in the samples' chemical structure after thermal-processing. However, in the polypropylene aligner, differences were verified in the region attributed to the crystalline phase. Differential Scanning Calorimetry analysis for the same sample showed a crystallinity fraction decrease due to relaxation between polymer chains after molding. In the tensile tests evaluated, the tensile strength and 'Young's modulus presented higher values for aligners containing 100% polyethylene terephthalate glycol. Performing an analogy exercise of the properties of orthodontic wires used in conventional fixed appliances and, relating them to orthodontic plastics, aligners composed of different materials and/or thicknesses could be used in increasing sequence in terms of the modulus of elasticity, starting with C+, which has a lower elastic modulus value, using the ACE 035 as an intermediate and finishing with the Crystal 0.75 and 1.0, providing the desired stiffness to the aligners for the final phase. more...

In this work lignocellulosic fibers were obtained from Yucca aloifolia L. leaves and their chemical, morphological, thermal and mechanical properties were studied. The fibers were pullout from the leaves and characterized by infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), chemical characterization, thermogravimetric analysis (TGA), single fiber tensile tests and scanning electron microscopy (SEM). The cellulose crystallinity index found was 69.43%. The fibers presented a high cellulose content, ~ 52.5%, and they are thermally stable until 193.4 °C. The tensile test for single fibers showed average results for the tensile strength of 800 MPa, Young's modulus of 39 GPa, and 2% strain at failure. Morphological analysis indicated the presence of a large number of parenchymal cells and not cellulosic constituents in fiber surface. These results indicated that Yucca aloifolia L. fibers have potential to application in polymeric matrices as fibrous reinforcement material. more...

The essential oil (EO) of pink pepper has important biological properties that can enhance its application in the pharmaceutical, cosmetic and food industries. The objective of this study was to characterize the EO of pink pepper seeds in terms of their chemical composition and thermophysical properties. Certified pink pepper seeds obtained commercially were used. The EO was extracted by hydrodistillation and chemically characterized in a gas chromatograph coupled to mass spectrometer (GC/MS). The thermoanalytical characterization was performed on a simultaneous high resolution equipment, and the Thermogravimetric Analysis (TG) and Differential Scanning Calorimetry (DSC) were used to determine the physical-chemical and kinetic properties of the OE in the room temperature range up to 250 ºC in the 20 ºC.min-1 ratio under nitrogen atmosphere. The Arrhenius kinetic model was applied to determine the activation energy of the EO. A total of 51 chemical compounds were detected in the pink pepper EO, of which 42 compounds were identified (54.7% of monoterpene compounds and 45.3% sesquiterpenes). The major components were ?-pinene (26.80%), germacrene D (11.25%), sabinene (11.13%) and terpinen-4-ol (8.59%). The thermogravimetric analysis indicated a single stage of thermo-degradation of the pink pepper EO between 74.8 ºC and 184.7 ºC, being an endothermic peak in the physical transition of vaporization. The variation of enthalpy and activation energy of EO were found with values of = - (39.8 ± 9.5) KJ.Kg-1 and = - (2,546 ± 0.033) KJ.mol-1, respectively. The data presented in the thermogravimetric analysis of pink pepper seeds EO allowed observing important thermal parameters for the definition of industrial processes that can use it as raw material, so that its biological activities can remain stable under controlled temperature conditions and below the range degradation. more...

Vegetable-based proteins may be extracted from different sources using different extraction methods, among them, ultrasound-assisted extraction stands out. This review presents the current knowledge on ultrasound-assisted extraction (UAE) and the functional properties of extracted vegetable proteins. Ultrasound generates cavitation in a liquid medium, defined as gas and vapor microbubbles collapse under pressure changes large enough to separate them in the medium. Cavitation facilitates the solvent and solid interaction, increasing yield and reducing extraction periods and temperature used. Moreover, ultrasound treatment changed extracted protein properties such as solubility, hydrophobicity, emulsifying and foam, water and oil absorption capacity, viscosity, and gelatinization. Ultrasound-assisted extraction is a promising technique for the food technology sector, presenting low environmental impact, lower energy and solvent consumption, and it is in accordance with green chemistry technology and sustainable concepts. more...

Cellulose nanofibers (CNF) have been applied in composite systems due to the abundance of raw material, excellent mechanical and thermal properties. In this work, CNF was prepared from agroindustrial waste and used in specified amounts in polyvinyl alcohol (PVA) composites. The FTIR spectra of CNF, chemically purified cellulose (CPC) and Cassava Agro-industrial Waste (CAW) indicate the removal of hemicellulose and lignin. The increase of the crystallinity phase in CNF was observed, by XRD analysis and neither is observed the transition from cellulose I to II. Thermogravimetric analysis showed displacement that the initial degradation of the CNF over 43 °C degradation proceeds at single step. The chemical and dimensional homogeneity of CNF can be observed with the calculation of the crystalline phase content obtained by deconvoluted dTG curve and XRD spectra, obtaining 80% crystallinity by both techniques. SEM micrographs showed fibers with diameters of 22.30 ± 1.52 nm. An increase in the mechanical properties of PVA was observed with the addition of CNF. With 2.5% CNF in the PVA, the elastic module increased by approximately three times, with the addition of 10% CNF, a saturated system with poor mechanical properties was observed. more...

Incineration of plastic materials for the energy generation is one of the types of polymer recycling, however the composition of the atmosphere used in this process must be controlled, since the products generated during the incineration and released into the atmosphere can be harmful to environment. Combination of different polymers and the mixing of this with other municipal solid wastes can generate varied products, accentuating the toxicity of the evolved gases. Thus, in this work, mass loss, amount of main stages and the gases evolved during polyethylene (PE) and polyvinyl chloride (PVC) thermolysis, as well as the physical mixture of both polymers, were analyzed by the evolved gas analysis using hyphenated techniques Thermogravimetry and Infrared Spectroscopy. Analyzes were conducted under inert and oxidizing atmosphere and showed that the products formed in the samples thermolysis were chemically different in the two atmospheres. During the thermogravimetric analysis under oxidizing atmosphere, even O2 is present in a significant amount, the products formed are dependent on the temperature of the thermolysis process, being able to generate carbon dioxide and carbonylated, carboxylated compounds, carbon monoxide and others products. more...

No intuito de diminuir os impactos das atividades humanas sobre o ambiente aquatico, ao descarregar determinado efluente em um receptor hidrico garantindo que este esteja dentro dos parâmetros definidos pela legislacao vigente, e preciso buscar tecnologias adequadas que demonstrem, principalmente, viabilidade economica, social e ambiental para seu tratamento. As sementes da Moringa oleifera , contem agente ativo com propriedade coagulante, com capacidade de remocao de bacterias presentes na agua na ordem de 90 a 99%. A tecnica de usar produtos de origem vegetal permite o desenvolvimento de substâncias de tratamento que diminui ou elimina a utilizacao de produtos sinteticos e/ou inorgânicos, gerando, assim, menor impacto ao ecossistema e garantindo manejo sustentavel do processo produtivo. Desta forma, o objetivo da pesquisa foi verificar o efeito da utilizacao do extrato das sementes de Moringa oleifera e do oleo essencial do Eucalyptus citriodorus em efluentes, in natura e pos-tratamento, sobre coliformes totais e Escherichia coli , existente nos efluentes de industria de processamento de mandioca para a fabricacao de amido. Utilizando amostras das lagoas de decantacao, tratado com extrato aquoso de sementes de Moringa e extrato de folhas de eucaliptos em diferentes concentracoes, foram realizadas diversas baterias de analises com a contagem de microrganismos de interesse. Atraves das analises microbiologicas, foi observado que ocorreram diferencas significativas, indicando resultados promissores, entre os efluentes com e sem tratamento, utilizando-se o extrato de sementes de Moringa oleifera e do Eucalyptus citriodorus com relacao ao tratamento convencional. more...

El objetivo de este estudio es evaluar el efecto de diferentes aceites (soja, girasol, canola y pollo) en el alimento para pollos, creados para el rendimiento de los pollos de engorde. Se analizaron los contenidos de perfil de ácidos grasos, colesterol en carne de pollo y sus respectivos rendimientos como pollos de engorde. Los 1,000 machos de pollos de engorde de Cobb de 42 días de vida, solo fueron alimentados con una dieta específica, y después de este período fueron sacrificados. Los pollos utilizados como control se sacrificaron a los 21 días de edad, estos pollos se alimentaron a base de una dieta comercial. Se informa que el rendimiento del pollo de engorde, el contenido de colesterol y la composición fisicoquímica de la alimentación en los cortes de carne (pechuga sin piel, piel de la pechuga y muslo sin piel) se ven afectados por la alimentación específica. El perfil de ácidos grasos de la dieta varió dependiendo de cada aceite utilizado en la formulación, encontrándosevalores más bajos de ácidos grasos saturados (SFA) para los aceites de canola y girasol. En la carne de pollo, los resultados para el muslo sin piel, la pechuga sin piel y la piel de la pechuga fueron similares a los perfiles de ácidos grasos, variando solo el tipo de tratamiento de alimentación. Después del análisis de las muestras, los ácidos grasos poliinsaturados (PUFA), que aparecen en mayor concentración, son 18: 2n-6 y 18: 3n-3. Por lo tanto, los cortes de pollos alimentados con aceites de girasol y soja evidenciaron niveles más altos de 18: 2n-6. Variablemente, los cortes de pollo alimentados con aceite de canola, mostraron niveles más altos de 18: 3n-3, en comparación con otros tratamientos. Considerando el equilibrio de n-6 / n-3 y la concentración de ácido graso insaturado en la carne de pollo, los pollos alimentados con aceite de canola presentaron mejores características nutricionales. more...

Polyethylene terephthalate is a polymer commonly used in food packaging which recycling potential should be explored with new studies. Lignin is the second most abundant biomass resource in the nature. Kraft lignin is a byproduct of the kraft pulping process, it is produced in large quantities. In this work PET/KL blends were produced in 1, 2, 5, 10 wt% of KL. These polymers were processed by extrusion, aiming to produce an alternative engineering material. Samples were investigated by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), Scanning Electronic Microscopy (SEM) and Tensile Test. Samples of extruded PET and PET/KL show differences in the pre-crystallization temperature. PET has higher pre-crystallization and melting temperature, as well as higher melting enthalpies. At 140 °C the presence of lignin reorders PET morphology, inducing the increase of the crystalline phase in the systems. The amount of KL in the sample influences also the sample morphology, which can results in a phase separation. more...

O presente trabalho teve como objetivo analisar a estabilidade térmica de um óleo essencial comercial de tomilho, submetido a cinco temperaturas diferentes de tratamentos térmicos e dois estados de armazenamento. Utilizou-se as técnicas de Análise Termogravimétrica e Calorimetria Exploratória Diferencial e a estabilidade termoquímica do óleo essencial foi caracterizada por meio de Cromatografia Gasosa e Espectroscopia no Infravermelho por Transformada de Fourier. Houve estabilidade e sem perda de massa do óleo essencial de tomilho até aproximadamente 75 °C. Resultados indicaram que não ocorreu flutuação do comportamento térmico nas amostras estocadas hermeticamente durante os tratamentos térmicos, enquanto que nas amostras acondicionadas em estado aberto, o comportamento térmico foi otimizado até o tratamento a 60 °C. As alterações da composição química e dos grupo funcionais do óleo essencial sob aquecimento e condição de acondicionamento também foram avaliadas. more...

The use of araucaria pine nut shell in polymer composites may increase the pine nut value and help protec araucaria (Araucaria angustifolia) itself, which is an endangered species. The aim of this work is to study the influence of the size of pine nut shell fiber on the mechanical properties of composites made of this shell and polyurethane derived from castor oil. Composites with different polyurethane contents were manufactured with dried untreated pine nut shell sieved through 30 and 50 mesh sieves (0.6 and 0.3 mm, respectively). Composites were shaped by mechanical mixing of the components followed by hot pressing. Properties such as density, water absorption, and flexural strength were measured. Specimens were also characterized by SEM, FTIR, and TGA. The flexural strength of PU/0.3mm pine nut shell composites with 30% PU (wt%) was 57.7 MPa, and their water absorption was 7.37% after 24 hours of immersion Made available in DSpace on 2019-07-03T00:40:47Z (GMT). No. of bitstreams: 1 2019WashingtonPTheinfluence.pdf: 4347434 bytes, checksum: dc3e162d437d6f4f89d29dfefc322496 (MD5) Previous issue date: 2019 more...

For the photocatalytic degradation of the hydrogen sulphide (H2S) in the gas-phase it was developed a rectangular reactor, coated with acrylic paint supported on fiber cement material. The surface ... more...

The adsorption of acetic acid and methanol on H-Beta zeolite as a model of reaction of first step of the esterification reaction has been investigated with TGA-IR coupled, ATR-FTIR spectroscopy together with Density Functional Theory (DFT) calculations at M06–2X/6-31G(D) level. From the theoretical viewpoint, different models of adsorption of acetic acid and methanol on the surface of H-Beta zeolite are studied. TGA-IR experiments show that both reactants are molecularly adsorbed on H-Beta, beyond 200 °C for methanol and 250 °C for acetic acid other species are also formed due to the surface reactivity being strongly adsorbed on the catalyst. Results from ATR-FTIR spectroscopy and theoretical calculations reveal that the predominant adsorption mode of acetic acid involves the ads_AA(C[dbnd]O) complex where the acetic acid is molecularly adsorbed by the carbonyl group on the Brønsted acid site of catalyst, and the OH group is oriented to the Al-O-Si bridge. The mechanism of adsorption of both acetic acid and methanol is also discussed at molecular level. The complexes where the acetic acid is adsorbed by the carbonyl group are clearly the most stable one. Fil: Gomes, Glaucio José. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas y Naturales y Agrimensura. Departamento de Ecología de Anfibios; Argentina. Universidade Estadual Do Oeste Do Pará; Brasil Fil: Zalazar, Maria Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas y Naturales y Agrimensura. Departamento de Ecología de Anfibios; Argentina Fil: Lindino, Cleber A.. Universidade Estadual Do Oeste Do Pará; Brasil Fil: Scremin, Fernando R.. Universidade Tecnologica Federal do Paraná; Brasil Fil: Bittencourt, Paulo R.S.. Universidade Tecnologica Federal do Paraná; Brasil Fil: Costa, Michelle Budke. Universidade Tecnologica Federal do Paraná; Brasil Fil: Peruchena, Nelida Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas y Naturales y Agrimensura. Departamento de Ecología de Anfibios; Argentina more...

Partially hydrogenated soybean oil and palm olein are oils that are widely used in the food industry. Continuous contact with air may cause changes of the triglycerides chemical structure, to eventually produce substances of lower molar masses that may be toxic to mammals. This study aimed to determine the kinetic parameters for the thermal oxidation of these oils and of their residual used oils from the pre-frying industrial step on preparing breaded chicken meat. The main reactions were followed by thermogravimetry (TG) and differential scanning calorimetry (DSC); the formation of the produced substances was monitored by gas chromatography flame ionization detector (GC-FID) and Fourier transform infrared spectroscopy (FTIR). These analyses indicated different chemical pathways, according to the type of unsaturation and changes in the molecular structures of the fatty acids in the oils. From the thermal analysis, more than one decomposition event was observed during the thermal oxidation process. As the soybean oil has a lower oxidation onset temperature than palm olein, it has lower rate of mass loss, with a higher activation energy value. more...