S Work
Mostrando 1-12 de 9216 artigos, teses e dissertações.
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1. Catalysts Derived from Thermal Treatments of Hydrocalumite-Type Compounds: Synthesis and Application in Transesterification Reactions
Catalyst performance is a relevant factor in biodiesel production because it can affect the efficiency of the process. This work provides a study of the performance of heterogeneous catalysts for biodiesel production derived from thermal-treated hydrocalumite-type compounds. This work aimed to synthesize and characterize hydrocalumite-type compounds intercal
Journal of the Brazilian Chemical Society. Publicado em: 2023
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2. Bimetallic Au-Pd/α-MoO3 Catalyst with High Oxygen Vacancies for Selective Oxidation of Cinnamyl Alcohol
Supported Au-Pd nanoparticles (NPs) have been extensively studied in alcohol oxidation reactions. However, few studies use reducible metal oxides as support, which can activate oxygen molecules and boost the selectivity of the reaction. In this work, Au-Pd NPs were supported on α-MoO3 and evaluated in the selective oxidation of cinnamyl alcohol without solv
Journal of the Brazilian Chemical Society. Publicado em: 2023
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3. Variational Formulation and A Priori Estimates for the Galerkin Method for a Fractional Diffusion Equation
ABSTRACT In this work we obtain a variational formulation and a priori estimates for approximate solutions of a problem involving fractional diffusion equations.
Trends in Computational and Applied Mathematics. Publicado em: 2022
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4. A Finite-Difference Time-Domain Formulation for Modeling Air Ionization Breakdown Streamers
Abstract A numerical model based on the finite-difference time-domain (FDTD) method is developed for calculating discharge currents and fields produced due air ionization between two electrodes. Electric conductivity σ of the ionized channel between two electrodes is calculated using non-linear equations, i.e., σ is obtained using functions of time. The fu
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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5. Radiation Efficiency of an Electrically Small Dual-band UHF Microstrip Patch Antenna Using Wheeler Cap Method
Abstract Determining the radiation efficiency of an antenna is a difficult task that becomes challenging when it is about electrically small antennas. This work investigates the applicability of the Wheeler cap method to measure the radiation efficiency of a UHF dual-band compact microstrip patch antenna. An overview of Wheeler method is presented. An adapta
Journal of Microwaves, Optoelectronics and Electromagnetic Applications. Publicado em: 2022
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6. Anomalous Diffusion with Caputo-Fabrizio Time Derivative: an Inverse Problem
ABSTRACT In this work we identify the source in a 1D anomalous diffusion equation, from measurements of the concentration at a finite number of points. We use Caputo-Fabrizio time fractional derivative to model the phenomenon. Separating variables, we arrive to a linear system which provides approximate values for the Fourier coefficients of the unknown sour
Trends in Computational and Applied Mathematics. Publicado em: 2022
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7. Tandem Synthesis of Furanaphthoquinones via Enamines and Evaluation of Their Antiparasitic Effects against Trypanosoma cruzi
Furanaphthoquinones are well known in medicinal chemistry for exhibiting relevant structural heterogeneity and bioactivities. In this work, it was synthesized a series of furanaphthoquinones through a tandem reaction between lawsone (8) and cyclic ketones in the presence of morpholine. This strategy provides an efficient and general method for synthesizing f
Journal of the Brazilian Chemical Society. Publicado em: 2022
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8. Determination of 3,4,5-Trihydroxybenzoic Acid Exploiting a Visible-Light-Driven Photoelectrochemical Platform: Application in Wine and Tea Samples
The present work is based on the development and application of a photoelectrochemical method for the amperometric determination of 3,4,5-trihydroxybenzoic acid in different samples. The method is based on the use of a photoelectrochemical platform based on a glass slide coated with fluorine-doped tin oxide, which has been modified with cadmium sulfide and p
Journal of the Brazilian Chemical Society. Publicado em: 2022
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9. Supercritical Carbon Dioxide Effect on Lipase-Catalyzed Geranyl Acetate Synthesis
This work provides a general insight on lipase-catalyzed synthesis of geranyl acetate through esterification of geraniol with acetic acid. Although this reaction is relatively well known, the replacement of organic solvents by supercritical fluids is fairly recent and the role of CO2 is still not completely understood. Therefore, reactions were performed wit
Journal of the Brazilian Chemical Society. Publicado em: 2022
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10. FUZZY MODELING OF SALINITY EFFECTS ON PUMPKIN (Cucurbita pepo) DEVELOPMENT
ABSTRACT The low quality of the water currently used for irrigation purposes harms the quality of the products and can lead to a reduction in production. Thus, the objective of this work was to verify the effect of saline water in irrigation water, on biometric variables of pumpkin crop using a system based on fuzzy rules. The agronomic experimental part of
Engenharia Agrícola. Publicado em: 2022
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11. Properties and technical characteristics of Casira pottery, Jujuy, Argentina
Abstract In this work, the results of a multi-technique characterization of a type of pottery production with high cultural and economic relevance from the only potter town in Argentina are presented and correlated. Raw materials, a prepared paste, and ceramic samples were studied. Chemical, structural, textural, microstructural, and thermal features were as
Cerâmica. Publicado em: 2022
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12. Light-Assisted Batch Injection Analysis of Glucose Exploiting a p-n-Homojunction Based on Cu2O
This work describes the development of a photoelectrochemical sensor for glucose quantification exploiting a light assisted-batch injection analysis (BIA) cell. A light-emitting diode (LED) lamp was employed to control the incidence of light on the p-Cu2O/n-Cu2O/fluorine-doped tin oxide (FTO) photoactive platform in BIA cell. The p-Cu2O/n-Cu2O/FTO platform w
Journal of the Brazilian Chemical Society. Publicado em: 2022