The goal of this one year study was to demonstrate that sub-50 pun mcxl drop size sprays can be produced when using an effervescent atomizer to spray high viscosity, non-Newtonian fluids at mass flow rates up to 1 kg/s. That goal was met. A secondary goal was to determine the spatial structure of the spray, in terms of how mean drop size and the width of the drop size distribution varied with axial and radial position within the spray. That objective was also met. 1991- 1992 begins the first year of our three year study into the fundamental mechanisms responsible for effervescent atomization. This year, we will be focusing on the transition region where the two-phase supersonic flow that exits the nozzle as discrete gas bubbles in a continuous liquid is transformed into a continuous gas stream containing discrete liquid drops. Single and multiple-pulse holography will be used to obtain the data nqcessary to achieve that goal. In particular, single-pulse holography will be used to determine the mechanisms of effervescent atomization while multiple-pulse holography will be used to determine drop size distribution and droplet velocities. A qualitative explanation of the mechanisms responsible for effervescent atomization should be available by the 1992 annual meeting with the first quantitative results availible later in 1992.