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Influence of mass transfer on bubble plume hydrodynamics Anais da ABC (AABC)
LIMA NETO,IRAN E.; PARENTE,PRISCILA A.B..
ABSTRACT This paper presents an integral model to evaluate the impact of gas transfer on the hydrodynamics of bubble plumes. The model is based on the Gaussian type self-similarity and functional relationships for the entrainment coefficient and factor of momentum amplification due to turbulence. The impact of mass transfer on bubble plume hydrodynamics is investigated considering different bubble sizes, gas flow rates and water depths. The results revealed a relevant impact when fine bubbles are considered, even for moderate water depths. Additionally, model simulations indicate that for weak bubble plumes (i.e., with relatively low flow rates and large depths and slip velocities), both dissolution and turbulence can affect plume hydrodynamics, which...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Aeration; Bubbles; Hydrodynamics; Mass transfer; Modeling; Oxygenation.
Ano: 2016 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652016000100411
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Glucose isomerization in simulated moving bed reactor by Glucose isomerase BABT
Silva,Eduardo Alberto Borges da; Souza,Antônio Augusto Ulson de; Rodrigues,Alírio Egídio; Souza,Selene Maria Arruda Guelli Ulson de.
Studies were carried out on the production of high-fructose syrup by Simulated Moving Bed (SMB) technology. A mathematical model and numerical methodology were used to predict the behavior and performance of the simulated moving bed reactors and to verify some important aspects for application of this technology in the isomerization process. The developed algorithm used the strategy that considered equivalences between simulated moving bed reactors and true moving bed reactors. The kinetic parameters of the enzymatic reaction were obtained experimentally using discontinuous reactors by the Lineweaver-Burk technique. Mass transfer effects in the reaction conversion using the immobilized enzyme glucose isomerase were investigated. In the SMB reactive system,...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Simulated moving bed reactor; Glucose isomerization; Enzymatic kinetics; Mass transfer; Mathematical model; Dynamic simulation.
Ano: 2006 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132006000400018
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Numerical study of n-pentane separation using adsorption column BABT
Silva,Adriano da; Mariani,Viviana Cocco; Souza,Antônio Augusto Ulson de; Souza,Selene Maria de Arruda Guelli Ulson.
This work simulated numerically the n-pentane separation of a mixture of iso-pentane, n-pentane and nitrogen, using an adsorption column with zeolite 5A. The mathematical model equations of the mass and heat transfer in the adsorption column are presented, as well as the boundary and initials conditions, beyond some hypotheses and considerations. The Volume Finite Method was used in the discretization of the equations to get the system of algebraic equations and posterior development of the computational algorithm. The numerical results using the Differencing Central (CDS) and Upwind (UDS) interpolations were compared with experimental results found in the literature. The influence of the partial pressure in the adsorption column performance was also...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Adsorption column; Mass transfer; Finite volume method.
Ano: 2005 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132005000400033
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Hydration kinetics, physicochemical composition, and textural changes of transgenic corn kernels of flint, semi-flint, and dent varieties Ciênc. Tecnol. Aliment.
Marques,Barbara Celuppi; Jorge,Luiz Mario de Matos; Jorge,Regina Maria Matos.
The hydration kinetics of transgenic corn types flint DKB 245PRO, semi-flint DKB 390PRO, and dent DKB 240PRO was studied at temperatures of 30, 40, 50, and 67 °C. The concentrated parameters model was used, and it fits the experimental data well for all three cultivars. The chemical composition of the corn kernels was also evaluated. The corn cultivar influenced the initial rate of absorption and the water equilibrium concentration, and the dent corn absorbed more water than the other cultivars at the four temperatures analyzed. The effect of hydration on the kernel texture was also studied, and it was observed that there was no significant difference in the deformation force required for all three corn types analyzed with longer hydration period.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Diffusion; Kinetic model; Mass transfer; Cereals and grains; Chemical composition; Physical properties; Food properties.
Ano: 2014 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612014000100013
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THE EFFECTIVE DIFFUSIVITY OF CLOVE(Eugenia caryophyllus) ESSENTIAL OIL IN PRESSURIZED CO2 Ciênc. Tecnol. Aliment.
ZAPATA NOREÑA,Caciano; MEIRELES,M. Angela A..
The effective diffusivity of clove essential oil in subcritical liquid CO2 was estimated. The experimental apparatus employed was a fixed-bed extractor. The fixed bed was formed with grounded (mesh -32 + 65) and compacted clove buds which were considered a solid element. The effective diffusion coefficient was evaluated by fitting the experimental concentration profile to the unsteady state mass balance equation for unidirectional diffusion in a finite solid medium. The diffusion coefficient was related to the concentration of oil in the solid by an exponential function. The estimated values of the effective diffusion coefficient varied from 3.64 to 5.22x10-10 m2/s. The average relative errors were lower than 3.1%.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Diffusion coefficient; Mass transfer; Finite difference; Clove essential oil; Supercritical extraction.
Ano: 1997 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20611997000400010
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Prediction of moisture transfer parameters for convective drying of shrimp at different pretreatments Ciênc. Tecnol. Aliment.
COSTA,Marcus Vinicius da; SILVA,Aline Kazumi Nakata da; RODRIGUES,Priscila Rodrigues e; SILVA,Luiza Helena Meller da; RODRIGUES,Antonio Manoel da Cruz.
Abstract By the analytical model proposed by Dincer and Dost, the mass transfer parameters (moisture transfer coefficient and moisture diffusivity) of shrimp samples were determined. Three sets of drying experiments were performed with three samples of shrimp: without boiling (WB), boiled in salt solution (SB) and boiled in salt solution and subjected to liquid smoking process (SBS). The experiments were performed under controlled conditions of drying air at temperature of 60°C and velocity of 1.5 m/s. Experimental dimensionless moisture content data were used to calculate the drying coefficients and lag factors, which were then incorporated into the analytical model for slab and cylinder shapes. The results showed an adequate fit between the experimental...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Shrimp drying; Mass transfer; Heat transfer; Mathematical modeling.
Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612018000400612
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Analysis of applicability of Peleg model to the cooking-infusion of mackerel (Scomber japonicus) slices Ciênc. Tecnol. Aliment.
Checmarev,Gerardo; Casales,María Rosa; Yeannes,María Isabel.
Mass transfer kinetics in osmotic dehydration is usually modeled by Fick's law, empirical models and probabilistic models. The aim of this study was to determine the applicability of Peleg model to investigate the mass transfer during osmotic dehydration of mackerel (Scomber japonicus) slices at different temperatures. Osmotic dehydration was performed on mackerel slices by cooking-infusion in solutions with glycerol and salt (a w = 0.64) at different temperatures: 50, 70, and 90 ºC. Peleg rate constant (K1) (h(g/gdm)-1) varied with temperature variation from 0.761 to 0.396 for water loss, from 5.260 to 2.947 for salt gain, and from 0.854 to 0.566 for glycerol intake. In all cases, it followed the Arrhenius relationship (R²>0.86). The Ea (kJ / mol)...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Mackerel; Osmotic dehydration; Mass transfer; Temperature effect; Modeling.
Ano: 2013 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612013000400013
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Effect of process variables on the osmotic dehydration of star-fruit slices Ciênc. Tecnol. Aliment.
Campos,Camila Dalben Madeira; Sato,Ana Carla Kawazoe; Tonon,Renata Valeriano; Hubinger,Míriam Dupas; Cunha,Rosiane Lopes da.
The objective of this work was to study the effect of blanching and the influence of temperature, solution concentration, and the initial fruit:solution ratio on the osmotic dehydration of star-fruit slices. For blanching, different concentrations of citric and ascorbic acids were studied. The samples immersed in 0.75% citric acid presented little variation in color in relation to the fresh star-fruit. Osmotic dehydration was carried out in an incubator with orbital shaking, controlled temperature, and constant shaking at 120 rpm. The influence of process variables was studied in trials defined by a complete 23 central composite design. In general, water loss and solids gain were positively influenced by temperature and by solution concentration....
Tipo: Info:eu-repo/semantics/article Palavras-chave: Averrhoa carambola; Blanching; Osmotic dehydration; Mass transfer.
Ano: 2012 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612012000200023
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Influence of film coefficient during multicomponent diffusion – KCl/NaCl in biosolid for static and agitated system using 3D computational simulation Ciênc. Tecnol. Aliment.
CREMASCO,Hágata; GALVAN,Diego; ANGILELLI,Karina Gomes; BORSATO,Dionísio; OLIVEIRA,Admilton Gonçalves de.
Abstract The influence of film coefficient formed during the diffusion of inorganic salts (NaCl and KCl) in biosolids was studied using a 3D computer modeling by Finite Elements Method (FEM) in COMSOL Multiphysics® software combined with SOM-type Artificial Neural Networks (ANN). Such tools have shown that the influence of the film formed in the biosolid/solution interface occurs in a heterogeneous manner and is due to the matrix geometry, the type of system (agitated or static) and the ion size (Na+ or K+). The influence of film coefficient was more pronounced for K+ ion, and for a static system. Comparing the geometry of biosolids, ion diffusion was more pronounced in the (Y±) axis in relation to other axes, X (±) and Z (±), as well as in between the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Finite elements method; Mass transfer; Modeling; Brines.
Ano: 2019 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612019000500173
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Water and sucrose diffusion coefficients during osmotic dehydration of sapodilla (Achras zapota L.) Ciência Rural
Coimbra,Lívia Muritiba Pereira de Lima; Arruda,Hayanna Adlley Santos de; Machado,Erilane de Castro Lima; Salgado,Silvana Magalhães; Albuquerque,Sônia Sousa Melo Cavalcanti de; Andrade,Samara Alvachian Cardoso.
ABSTRACT: Sapodilla is an original fruit from Central America that is well adapted in all regions of the Brazilian territory. Despite its wide adaptation and acceptance in fruit markets, it is rare to find it outside tropical regions, partially because of its high perishability. The development of alternative, simple, and inexpensive methods to extend the conservation and marketing of these fruits is important, and osmotic dehydration is one of these methods. The main objective of this study was to determine the water and sucrose diffusion coefficients during the osmotic dehydration of sapodilla. This process was performed in short duration (up to 6h) to evaluate detailed information on water loss and solids gain kinetics at the beginning of the process...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Osmotic dehydration; Mass transfer; Diffusion coefficient; Sapodilla.
Ano: 2017 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-84782017000800204
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Mass transfer efficiency of a vacuum airlift-Application to water recycling in aquaculture systems ArchiMer
Barrut, Bertrand; Blancheton, Jean-paul; Champagne, Jean-yves; Grasmick, Alain.
In aquaculture, oxygen transfer and carbon dioxide stripping are the first limiting factors to fish rearing intensification. In this study we measured the O-2 and CO2 mass transfer coefficient (K(L)a) for a vacuum airlift in fresh (<1% salinity) and sea water (35 parts per thousand salinity) recirculating aquaculture systems (RAS). The airlift was composed of two concentric tubes: an inner riser tube and an external downcomer tube and can be adjusted at three different heights: 2,4 or 6 m. Several types of air injectors were tested, delivering different sizes of bubble swarms depending on their porosity and functioning conditions (low or high injection pressure), with air flows varying from 0 to 80 L min(-1). Experiments were also carried out at...
Tipo: Text Palavras-chave: Mass transfer; Airlift; Vacuum; Aquaculture; RAS; Aeration; Degasification; Salinity.
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00072/18324/16001.pdf
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Aspects temporels de l' impact de rejets radioactifs effectues en mer, sur les eaux d' une station littorale de la Manche ArchiMer
Fraizier, Albert; Guegueniat, Pierre; Salomon, Jean-claude.
Time-dependent impact of seaward radioactive discharges on waters of one coastal station of the English Channel. The disposai at sea of liquid waste from the nuclear fuel reprocessing plant at La Hague (CEA/Cogema) causes modifications to the radioactivity of marine waters in both space and time. Fluctuations in this radioactivity are controlled by many different parameters; to study these parameters, samples were taken, in particular, from a coastal site situated 5 km from the outlet pipe. The overall impact of these releases on the radioactivity of sea-water depends on various factors, including the amount and frequency of discharges, the hydrodynamic regime of water masses in the region and local meteorological conditions. In order to assess this...
Tipo: Text Palavras-chave: Manche; Eaux littorales; Radioactivité; Transferts; Analyse temporelle; Channel; Coastal waters; Radioactivity; Mass transfer; Time-series analysis.
Ano: 1992 URL: http://archimer.ifremer.fr/doc/1992/publication-541.pdf
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Salting kinetics and salt diffusivities in farmed Pantanal caiman muscle PAB
Telis,Vânia Regina Nicoletti; Romanelli,Pedro Fernando; Gabas,Ana Lúcia; Telis-Romero,Javier.
The legal Pantanal caiman (Caiman crocodilus yacare) farming, in Brazil, has been stimulated and among meat preservation techniques the salting process is a relatively simple and low-cost method. The objective of this work was to study the sodium chloride diffusion kinetics in farmed caiman muscle during salting. Limited volumes of brine were employed, with salting essays carried at 3, 4 and 5 brine/muscle ratios, at 15%, 20% and 25% w/w brine concentrations, and brine temperatures of 10, 15 and 20ºC. The analytical solution of second Fick's law considering one-dimensional diffusion through an infinite slab in contact with a well-stirred solution of limited volume was used to calculate effective salt diffusion coefficients and to predict the sodium...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Caiman crocodilus yacare; Mass transfer; Meat; Preservation; Processing; Brines.
Ano: 2003 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-204X2003000400012
Registros recuperados: 13
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