Finite element simulation of nonlinear convective heat and mass transfer in a micropolar fluid-filled enclosure with Rayleigh number effects

A mathematical model is presented to study the double-diffusive convective heat and mass transfer of a micropolar biofluid in a rectangular enclosure, as a model of transport phenomena in a bioreactor. The vertical walls of the enclosure are maintained at constant but different temperatures and concentrations. The conservation equations for linear momentum, angular momentum, energy and species concentration are formulated subject to appropriate boundary conditions and solved using both finite element and finite difference numerical techniques. Results are shown to be in excellent agreement between these methods. Several special cases of the flow regime are discussed. The distributions for streamline, isotemperature, isoconcentration and (isomicrorotation) are presented graphically for different Lewis number, buoyancy parameter, micropolar vortex viscosity parameter, gyration viscosity parameter, Rayleigh number, Prandtl number and micro-inertia parameter. Micropolar material parameters are shown to considerably influence the flow regime. The flow model has important applications in hybrid aerobic bioreactor systems exploiting rheological suspensions e.g. fermentation

Intervention or inspiration?: Kolam

This article explores a classic dilemma concerning the extent to which anthropologist fieldworkers may influence their fieldwork hosts. This dilemma arose in the course of the author’s research on kolam drawing practices among diaspora Tamils in the UK. Kolam constitute a popular visual practice among Tamils in India and Sri Lanka, but less so in the diaspora. However, the researcher’s interest in kolam practice began to awaken an interest on the part of diaspora Tamils in the UK and affect the very practices researched. Does this constitute an intervention or might it be considered an appropriate form of inspiration? The article makes a contribution to the literature on ethics and on diasporic communities, whose members, although reticent to perpetuate practices that might upset their host society, may nevertheless defer to researchers with specialist knowledge of their homeland. © RAI 2012.</p