Ultrasound reforms droplets.

Size-controlled monodisperse droplets are indispensable in food, cosmetics, and healthcare industries. Although emulsion formation from bulk phases is well-explored, a robust method to continuously reform existing emulsions is unavailable. Remarkably, we introduce a continuous flow acousto-microfluidics technique which enables simultaneous trapping-coalescence-splitting of droplets to reform an existing polydisperse emulsion into size-controlled droplets with improved monodispersity.

Monitored natural attenuation of a long-term petroleum hydrocarbon contaminated sites: a case study.

This study evaluated the potential of monitored natural attenuation (MNA) as a remedial option for groundwater at a long-term petroleum hydrocarbon contaminated site in Australia. Source characterization revealed that total petroleum hydrocarbons (TPH) as the major contaminant of concern in the smear zone and groundwater. Multiple lines of evidence involving the geochemical parameters, microbiological analysis, data modelling and compound-specific stable carbon isotope analysis all demonstrated natural attenuation of hydrocarbons occurring in the groundwater via intrinsic biodegradation.

Integration of traditional and innovative characterization techniques for flux-based assessment of dense non-aqueous phase liquid (DNAPL) sites.

Key attributes of the source zone and the expanding dissolved plume at a trichloroethene (TCE) site in Australia were evaluated using trends in groundwater monitoring data along with data from on-line volatile organic compound (VOC) samplers and passive flux meters (PFMs) deployed in selected wells. These data indicate that: (1) residual TCE source mass in the saturated zone, estimated using two innovative techniques, is small ( approximately 10 kg), which is also reflected in small source mass discharge ( approximately 3 g/day); (2) the plume is disconnecting, based on TCE concentration contours and TCE fluxes in wells along a longitudinal transect; (3) there is minimal biodegradation, based on TCE mass discharge of approximately 6 g/day at a plume control plane approximately 175 m from source, which is also consistent with aerobic geochemical conditions observed in the plume; and (4) residual TCE in the vadose zone provides episodic inputs of TCE mass to the plume during infiltration/recharge events. TCE flux data also suggest that the small residual TCE source mass is present in the low-permeability zones, thus making source treatment difficult.