Diffusion In Solids
Mostrando 1-12 de 17 artigos, teses e dissertações.
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1. DETERMINATION OF REACTIVITY AND THERMODYNAMIC ANALYSIS OF NICKEL-BASED OXYGEN CARRIERS FOR CHEMICAL-LOOPING COMBUSTION
Abstract This work aimed to study nickel-based oxygen carriers (OC) for Chemical Looping Combustion (CLC) using H2 and CH4 as fuel. The reactivity and reaction kinetics of the OC were investigated, applying the shrinking core, nucleation and diffusion models in three dimensions, as well as whether the OC is thermodynamically favorable for the reaction. The r
Braz. J. Chem. Eng.. Publicado em: 09/12/2019
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2. Mass transfer and kinetic modelling of supercritical CO 2 extraction of fresh tea leaves (Camellia sinensis L.)
Abstract Supercritical carbon dioxide extraction was employed to extract solids from fresh tea leaves (Camellia sinensis L.) at various pressures(15 to 35 MPa) and temperatures (313 to 333K) with addition of ethanol as a polarity modifier. The diffusion model and Langmuir model fit well to experimental data and the correlation coefficients were greater than
Braz. J. Chem. Eng.. Publicado em: 2017-07
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3. Metal Complex Derivatives of Azole: a Study on Their Synthesis, Characterization, and Antibacterial and Antifungal Activities
Four new zinc complex derivatives of azoles and ligands were synthesized and isolated as white air-stable solids and characterized by elemental analyses, thermogravimetric analysis (TGA), infrared spectroscopy, nuclear magnetic resonance (NMR) and mass spectra. The elemental analysis, theoretical calculations and NMR show that the complexes likely have a 1:1
J. Braz. Chem. Soc.. Publicado em: 2016-12
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4. Dip coating of a carbon steel sheet with Ni reinforced TiO2 nanoparticles
In this work carbon steel plates were dip-coated with a composite film obtained from a colloidal suspension of Ni-TiO2. Suspensions with different solids contents were used to evaluate the adherence of the film and the microstructural features. The samples were characterized using both optical and scanning electron microscopy, energy dispersive spectroscopy
Mat. Res.. Publicado em: 12/04/2016
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5. Enzyme loading dependence of cellulose hydrolysis of sugarcane bagasse
The enzymatic hydrolysis of steam-pretreated sugarcane bagasse, either delignified or non-delignified, was studied as a function of enzyme loading. Hydrolysis experiments were carried out using five enzyme loadings (2.5 to 20 FPU/g cellulose) and the concentration of solids was 2% for both materials. Alkaline delignification improved cellulose hydrolysis by
Quím. Nova. Publicado em: 2012
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6. Evaluation of water and sucrose diffusion coefficients during osmotic dehydration of jenipapo (Genipa americana L.).
The apparent diffusion coefficients for sucrose and water during osmotic dehydration of jenipapos were determined. Long time experiments (up to 60 h) were carried out in order to determine equilibrium concentrations inside jenipapos, whereas short time experiments (up to 4 h) were performed to provide detailed information on kinetics of water loss and solids
Journal of Food Engineering. Publicado em: 2011
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7. Partially aerated attached biomass bed reactor applied to treatment sanitary sewage treatment / Reator com leito de biomassa aderida aerado parcialmente aplicado ao tratamento de esgoto sanitário
This work aimed to evaluate the performance of a full scale up-flow attached biomass bed reactor (159 M POT.3) and with continuous aeration at 7 m above bottom of the reactor to sanitary sewage treatment. The bed of the reactor was constituted for activated granular carbon, anthracite carbon and sand. The work was divided into two stages. In the first stage,
Publicado em: 2010
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8. IMPLEMENTAÇÃO DA TÉCNICA DE FOTOACÚSTICA DE CÉLULA ABERTA PARA OBTENÇÃO DA DIFUSIVIDADE TÉRMICA DE METAIS
The photo-acoustic technique has become a standard photo-thermal method for carrying out diverse studies on solids materials. Photo-thermal phenomena in solids results from a combination of thermal expansion, thermal diffusion, and thermo-elastic bending effects and can be obtained by c k . r a = where k is the thermal conductivity, r is the density, and c i
Publicado em: 2009
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9. Mass transfer inside oblate spheroidal solids: modelling and simulation
A numerical solution of the unsteady diffusion equation describing mass transfer inside oblate spheroids, considering a constant diffusion coefficient and the convective boundary condition, is presented. The diffusion equation written in the oblate spheroidal coordinate system was used for a two-dimensional case. The finite-volume method was employed to disc
Brazilian Journal of Chemical Engineering. Publicado em: 2008-03
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10. Produção de nisina por Lactococcus lactis subsp. lactis ATCC 11454 utilizando meio sintético e leite desnatado, com ou sem suplementação de componentes extras, como meio de cultivo / Nisin production by Lactococcus lactis subsp. lactisATCC 11454 utilizing synthetic and natural media,skimm milk with or without extra suplementation"
Nisin is a bacteriocin produced by Lactococcus lactis that inhibits the germination and growth of Gram-positive bacteria. As Nisin expression is related to the growth conditions of Lactococcus lactis subsp. lactis, the effects of growth parameters, media components and incubation time, were studied to optimize the expression of Nisin. L. lactis ATCC 11454 wa
Publicado em: 2005
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11. Mass transport in spheroids using the Galerkin method
This work presents an analytical modelling of mass transfer in spheroidal solids using a liquid diffusion model. The diffusion equation, written in cylindrical coordinates, is solved using the Galerkin method with a constant diffusion coefficient and an equilibrium boundary condition at the surface of the solid. Results on the drying kinetics, and moisture c
Brazilian Journal of Chemical Engineering. Publicado em: 2004-12
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12. Propriedades microscopicas e macroscopicas de superficie em ligas ferrosas implantadas com nitrogenio
The understanding of cosmic radiation -the production/ acceleration mechanism and the propagation processes -involves the determination of three parameters: the energy of this radiation, its arrival direction and the chemical composition. These three tasks have challenged the experience, the skill and responsibility of several groups of particle physicists o
Publicado em: 2004