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This paper reports on an exploratory study examining the role of sexual cleansing rituals in the transmission of HIV among the Luo community in western Kenya. Data were collected using both in‐depth interviews and focus group discussions. The study population consisted of 38 widows, 12 community elders and 44 cleansers. Data were collected on non‐behavioural causes, behavioural causes and behavioural indicators associated with sexual rituals. Content analysis revealed five central themes: the effect of the ritual on sexual behaviours; factors contributing to the continued practice of the ritual, including a sub‐theme on the commercialization of the ritual; the inseparable relationship between the sanctity of sex, prosperity and fertility of the land; and the effects of modernization on the ritual, including a sub‐theme on the effects of mass media on HIV‐prevention awareness campaigns. Causal factors of unchanging sexual behaviours are deeply rooted in traditional beliefs, which the community uphold strongly. These beliefs encourage men and women to have multiple sexual partners in a context where the use of condoms is rejected and little HIV testing is carried out.

Mixing efficiency in stirred tanks is an important consideration in the design of many industrial processes. Computational fluid dynamics (CFD) techniques have been employed in the present work to study the hydrodynamics in a tank stirred by a Rushton turbine. The effect of the impeller clearance on the velocity field and mixing has been investigated. It has been shown that at a low impeller clearance, the Rushton turbine generates a flow field that evolves from the typical two loops to a single loop flow pattern similar to that of an axial impeller. This single loop flow pattern resulted in an increase in axial flow and a decrease in mixing time at a constant power number. It has been found that a draft tube can be used with a single Rushton turbine, at a low clearance to aid axial flow and mixing, and this resulted in 50% reduction in mixing time. There was a good comparison between laser Doppler velocimetry (LDV) experimental and CFD simulation flow fields, both of which showed that the draft tube improved mixing in the tank by suppressing secondary circulation loops.