Constants
Mostrando 13-24 de 2791 artigos, teses e dissertações.
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13. Kinetic modeling and evaluation of free radical-scavenging behavior in oils: application to four tropical and subtropical fruits in a DPPH system
Abstract A kinetic model was developed to represent the radical-scavenging capacity (RSC) for the oxidation of oils. The model was developed using second-order rate constants (k2) to represent the RSC. The RSC of the oils can be compared by the k2 values indicating their scavenging capacity. Furthermore, the k2 values can be used to determine the decay kinet
Food Sci. Technol. Publicado em: 2020-06
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14. The Catalytic Action of Copper Ions and the Rosemary Extract Antioxidant Effect in the Biodiesel Oxidation Reaction and the Implication in Arrhenius Behavior
Biodiesel contains esters in its composition which make it susceptible to oxidation. Among the factors that cause this reaction is the contamination with metal ions. In the present work, it was analyzed biodiesel samples obtained from a mixture containing 39.0% m/m soybean oil, 22.0% m/m beef tallow and 39.0% m/m poultry fat using a methyl route. Copper ions
J. Braz. Chem. Soc.. Publicado em: 2020-06
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15. Chemically Reduced Graphene Oxide on Gold Electrodes from Recordable CDs: Characterization and Potential Sensing Applications
This work presents the development and characterization of a new chemically modified electrode exploiting recordable Au-rewritable compact discs (AuCDs) as substrate for drop casting of a chemically-reduced graphene-oxide slurry focusing on simple and low-cost electrochemical sensors. Increase in electrochemical responses in cyclic voltammetric and amperomet
J. Braz. Chem. Soc.. Publicado em: 2020-03
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16. Mathematical Modeling of the Transesterification Reaction by Finite Elements: Optimization of Kinetic Parameters Using the Simplex Sequential Method
The use of biodiesel as fuel has been presented as a viable alternative in the search for renewable energies. It can be produced from the transesterification reaction of vegetable oils with methanol in the presence of sodium or potassium hydroxide as catalysts. In the present research, the transesterification reaction of soybean oil was modeled considering t
J. Braz. Chem. Soc.. Publicado em: 2020-02
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17. Hardening and Dynamic Recovery During Hot Compression Test of Copper Simulated as Viscoplastic Material
The Norton-Bailey equation was used to simulate by finite elements the hardening and dynamic recovery of copper during the hot compression tests. The constants of Norton-Bailey equation were determined from the Voce-Kocks model. The simulation assumes a Mortar Contact with Coulomb friction and axial symmetry. Numerical results were compared with experiments.
Mat. Res.. Publicado em: 05/12/2019
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18. Microstructural Analysis of AgIn5VI8 (VI: S, Se, Te) Ternary Semiconductors by X-Ray Diffraction
This work is a study of the microstructural properties of the polycrystalline ternary compounds AgIn5S8, AgIn5Se8, and AgIn5Te8 by X-ray diffraction technique (XRD). The full-width-half-maximum (FWHM) of the XRD profile is measured as function of the diffraction angle and used to estimate the microstructural parameters. In general, a microstructural characte
Mat. Res.. Publicado em: 14/11/2019
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19. New nonlinear solution of nearly incompressible hyperelastic FGM cylindrical shells with arbitrary variable thickness and non-uniform pressure based on perturbation theory
Abstract In this paper, nonlinear analysis of thick cylindrical shells with arbitrary variable thickness made of hyperelastic FGM with radially variation of material properties in nearly incompressible state under non-uniform pressure loading is presented. Thickness and pressure of the shell vary in axial direction by linear and/or nonlinear functions. The g
Lat. Am. j. solids struct.. Publicado em: 28/10/2019
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20. Investigation of the effect of nozzle design on rheological bioprinting properties using computational fluid dynamics
ABSTRACT Bioprinting is the utilization of techniques derived from three-dimensional printing to generate complex biological structures which may replace natural tissues or organs. It employs high spatial resolution deposition of different cell types, growth factors and biomaterials. Those together form bioinks, which are the bioprinting inputs, analogously
Matéria (Rio J.). Publicado em: 16/09/2019
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21. Kinetic modeling and evaluation of free radical-scavenging behavior in oils: application to four tropical and subtropical fruits in a DPPH system
Abstract A kinetic model was developed to represent the radical-scavenging capacity (RSC) for the oxidation of oils. The model was developed using second-order rate constants (k2) to represent the RSC. The RSC of the oils can be compared by the k2 values indicating their scavenging capacity. Furthermore, the k2 values can be used to determine the decay kinet
Food Sci. Technol. Publicado em: 09/09/2019
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22. Estudo das propriedades do Diodo Emissor de Luz (LED) para a determinação da constante de Planck numa maquete automatizada com o auxílio da plataforma Arduíno
Resumo No presente artigo, apresenta-se o método experimental de determinação da constante de Planck, uma das constantes físicas fundamentais, através do estudo das propriedades quânticas e ondulatórias do diodo emissor de luz (LED) numa maquete experimental automatizada, que contém um circuito eletrônico ligado a um computador utilizando o protocol
Rev. Bras. Ensino Fís.. Publicado em: 09/09/2019
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23. Study of Mechanical Behavior and X-Ray Elastic Constants of Nickel Alloy Weld Overlay
The study of nickel-based alloy 625 clad (weld overlay) by X-ray diffraction (XRD) is difficult and often impossible because of its coarse and anisotropic microstructure. In this work, a sample preparation including machining, grinding, and annealing was proposed to avoid this negative effect in XRD analysis. Electron backscatter diffraction and hardness tes
Mat. Res.. Publicado em: 10/07/2019
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24. Avaliação e estabilidade da cor em filés de burriquete (Pogonias cromis) utilizando um sistema de visão computacional
Resumo A cor da superfície da carne é a primeira sensação que o consumidor percebe e utiliza como uma ferramenta para aceitar ou rejeitar um alimento. A medição e a avaliação da cor da carne podem também ser feitas por um indicador químico (metamioglobina) ou pela avaliação física, utilizando espaços da cor (a* e R). O objetivo deste trabalho f
Braz. J. Food Technol.. Publicado em: 13/06/2019