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The topic of this study is related to airborne particle dynamics in indoor environments. Lab-scale experiments have been performed to investigate particle deposition velocity to six different surfaces orientations (with respect to gravity) for fully developed turbulent flow in horizontal large circular ventilation ducts. Monodispersed aerosol particles (1-6 μm) were used in the deposition experiments. A very low particle mass (40 ng) was measured reliably above background level on duct surfaces by a means of a nondestructive stencil technique associated with fluorescence analysis. For 2-6 μm particles (diffusion and impaction regime), deposition rates to floors were much greater than rates to the ceiling and greater than rates to the wall. For 1-μm particles, the effect of surface orientation to particle deposition was not significant. Results were compared to the very few similar and published studies. This work was conducted in the frame of the CleanAirNet project which aimed at producing new knowledge, models, and techniques to help controlling the safety food stuffs, through a better control of aerosol particle (bioaerosols) transport and deposition in the ventilation networks of the food industry. [ABSTRACT FROM AUTHOR]

In the tropics, cassava starch is produced at artisanal and industrial scales. This paper focuses on a new methodology enabling the technoeconomical comparison of small-scale cassava starch manufacturing process (1-5 t of starch/day) in two markedly different contexts (Colombia and Vietnam). Measurements were conducted during trial runs for each unit operation (washing/pealing, rasping, extraction and separation). Starch mass balance was calculated from sample composition (moisture, starch and crude fiber and ash content). Production capacity, water consumption, electric requirements and capital-labor costs were also measured. The manufacturing processes differed mainly on starch recovery from starch present in washed roots (65 vs. 76%), extraction capacity (0.3 vs. 0.9 t of washed roots/h), water consumption (45 vs. 21 m/t of dry starch), energy consumption (59 vs. 55 kWh/t of starch) and production costs (1,156 vs. 162 US$/t of starch) for Colombia and Vietnam, respectively. Moreover, the effectiveness of the starch extraction process could largely be attributed to the differences in the extent of root disintegration achieved with different rasping equipment. [ABSTRACT FROM AUTHOR]