Examinando por Materia "Transport phenomena"

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    Ítem
    Approximated analytical solution to an Ebola optimal control problem
    (Board Members, 2016-01-01) Hincapié-Palacio, D.; Ospina, J.; Torres, D.F.M.; Hincapié-Palacio, D.; Ospina, J.; Torres, D.F.M.; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
    An analytical expression for the optimal control of an Ebola problem is obtained. The analytical solution is found as a first-order approximation to the Pontryagin Maximum Principle via the Euler-Lagrange equation. An implementation of the method is given using the computer algebra system Maple. Our analytical solutions confirm the results recently reported in the literature using numerical methods.
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    Ítem
    Two-dimensional description of absorption in humans after dermal exposure to volatile organic compounds
    (TAYLOR & FRANCIS INC, 2017-06-03) Simon, Laurent; Ospina, Juan; Simon, Laurent; Ospina, Juan; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
    A two-dimensional diffusion model was developed to predict the absorption of chemicals in humans following dermal contact. A firstorder evaporation rate equation was applied to the skin surface while a perfect-sink boundary condition was imposed at the stratum corneum/viable epidermis interface. Initially, there was a certain amount of the substance present within the stratum corneum at the end of the exposure period. Laplace transform techniques were implemented to solve the governing equations and to derive an expression for the time elapsed before reaching 90% of the final amount of chemical absorbed by the body. This index was 0.43, 2.67, 6.91, and 36.9 h for ethanol, diphenylamine, p-nitroaniline, and benzyl butyl-phthalate, respectively. Simulations show that surface evaporation is important for highly volatile compounds. A large fraction of the amount of poorly volatile compounds, available in the skin after exposure, was absorbed into the bloodstream. © Taylor & Francis Group, LLC.