Journal of Applied Electrochemistry Diary

Calendar

Journal of Applied Electrochemistry Diary (Finalised on 04 October 2010)     

Systematic generation of a CAPE-OPEN compliant simulation module from GAMS and FORTRAN models

The adaptation of complex existing modules so that they meet the CAPE-OPEN (CO) standard is important in order to take advantage of previous work done for the simulation of processes. In this work we present the design and implementation of two different Operation-Unit (OU) modules that support the CO interface. Each resulting OU satisfies the definitions and guidelines established by the standard. The first module consists of a CO-compatible component for the steady-state simulation of a multi-bed ammonia reactor, whose original code had been written in FORTRAN. The second one, which also supports the CO interface, it is a GAMS-compatible module of a reactive distillation column. In order to develop these modules, an existing CO wizard that targets the mechanical generation of the OU Package was used. This wizard generates a Visual Basic project that contains the OU's source code and its installation package. In particular, the calculation routine and the Graphical-Unit Interface (GUI) were implemented. Before implementing the interfaces, an analysis of requirements for the correct interaction between the OU and the other simulator components was carried out. Both modules embedded in HYSYS take advantage of its complete property-package, which complements GAMS and FORTRAN in order to carry out the accurate computation of the chemical and equilibrium properties.     

Fractionation of industrial solids containing barley husks in aqueous media

Lignocellulosic materials, particularly the ones of residual nature generated in agricultural and industrial activities, represent a renewable, abundant and cheap source of raw materials for multiple purposes. Barley husks belong to this type of materials. Aqueous fractionation of a solid byproduct from malting industries (denoted MSW), mainly made up of barley husks, leads to a liquid phase containing bioactive components (oligosaccharides derived from hemicelluloses with prebiotic activity and low molecular weight phenolics with antioxidant activity) and to a solid phase containing cellulose and lignin as major components. Antioxidant compounds can be separated from fractionation liquors by physicochemical processing, providing a practical approach to sustainable development. Based on experimental data, the solubilization of MSW hemicelluloses is assessed in terms of kinetics, composition, material balances and properties of the isolated fractions. The nature, refining and properties of the antioxidant compounds extracted from liquors obtained by non-isothermal processing of MSW are discussed on the basis of experimental results.     

Sorption and optical properties of sol-gel thin films measured by X-Ray Reflectometry and Ellipsometric Porosimetry

Oxide thin films synthesized using the sol-gel technique have the advantages of low cost, high thickness control, tunable refractive index and silicon technology compatibility, properties that make them potential materials for optoelectronic applications. For very thin films with low porosity, the determination of sorption and optical properties is quite complex because of the small sample size. Thus, there is a need to use especially designed techniques to obtain reliable results. In this work, a comprehensive study on the porosity evolution of SiO₂ and TiO₂ thin films using X-Ray Reflectometry and Environmental Ellipsometric Porosimetry is presented. For sol-gel SiO₂ thin films, it was found that the effective refractive index increases with thermal treatment as the porosity decreases. However, the refractive index of the walls was found constant. For sol-gel TiO₂ films, crystallized in anatase phase, both the effective refractive index and the wall refractive index increase with thermal treatment. SiO₂ and TiO₂ thermal oxides were also characterized for comparison.