Modeling of Controlled Release of Betacarotene Microcapsules in Ethyl Acetate
Jucelio Kilinski Tavares,
Antônio Augusto Ulson de Souza,
José Vladimir de Oliveira,
Adriano da Silva,
Wagner Luiz Priamo,
Selene Maria Arruda Guelli Ulson de Souza
Issue:
Volume 4, Issue 2, December 2018
Pages:
23-33
Received:
5 July 2018
Accepted:
13 September 2018
Published:
17 October 2018
DOI:
10.11648/j.nsnm.20180402.11
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Abstract: In this work several models of mass transfer process were used for modelling and simulating active principles release of polymeric microcapsules of the matrix type. To demonstrate the performance of each model compared to the experimental data, a statistical analysis using the F test was done. The following mathematical models were used on this mass transfer problem: 2ª. Law of Fick (CDMASSA), LDF - Linear Drive Force, analytical model and others semiempiricals models. The results obtained were compared with those available in the literature. In this work the release of the active ingredient betacarotene, contained in microcapsules (PHBV) in the solvent ethyl acetate, was studied. It was observed that the model obtained from the 2ª. Law of Fick fits better on the literature data compared to the models: LDF, analytical andsemiempirical. s. The most complete model, based on the phenomenology of the problem, provide a better result, considering that it was able to represent the fundamental stages of the mass transfer process, such as the resistance to mass transfer on the microcapsule surface, werethe numerical results were very close to the experimental results.
Abstract: In this work several models of mass transfer process were used for modelling and simulating active principles release of polymeric microcapsules of the matrix type. To demonstrate the performance of each model compared to the experimental data, a statistical analysis using the F test was done. The following mathematical models were used on this mas...
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Corrosion Behavior of AA5038 Nanostructured Aluminum Alloy Produced by Accumulative Roll-Bonding
Ali Torkan,
Amin Rabiei Baboukani,
Iman Khakpour
Issue:
Volume 4, Issue 2, December 2018
Pages:
34-40
Received:
13 July 2018
Accepted:
30 September 2018
Published:
27 October 2018
DOI:
10.11648/j.nsnm.20180402.12
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Abstract: Accumulative roll bonding is the only severe plastic deformation process for the industrial production of ultrafine grained sheets with desirable mechanical properties. In the present research, corrosion behavior of nanostructured 5083 Aluminum alloy produced by Accumulative Roll Bonding (ARB) was carried out in 3.5% NaCl solution. Potentiodynamic Polarization tests and electrochemical impedance spectrometry were used to evaluate corrosion behavior of samples and immersion test was applied to evaluate intergranular corrosion behavior. The ARB process was successfully performed up to 6 cycles on 5083 aluminum alloy sheet. In early stages of ARB process, main grains were isolated by boundaries resulted from transformation and then layer structure composed of layer boundaries parallel to the rolling direction was created by increasing ARB cycle. By increasing the cycles distance between layer boundaries is decreased and finally by increasing strain more up to four cycles a structure made up of grains with nano grain size was obtained in result of occurrence of In-situ recrystallization. According to the electrochemical corrosion tests, by increasing number of passes in ARB process, the corrosion current density and corrosion rate was increased. Immersion test also revealed that the aluminum alloy annealed in 413°C and ARB samples are not sensitive to intergranular corrosion.
Abstract: Accumulative roll bonding is the only severe plastic deformation process for the industrial production of ultrafine grained sheets with desirable mechanical properties. In the present research, corrosion behavior of nanostructured 5083 Aluminum alloy produced by Accumulative Roll Bonding (ARB) was carried out in 3.5% NaCl solution. Potentiodynamic ...
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