AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
DMA Transfer Functions under Down Scan Operation
MARK KANAPARTHI, Suresh Dhaniyala, Clarkson University
Abstract Number: 343 Working Group: Instrumentation and Methods
Abstract Aerosol size distribution measurements are routinely made using a Scanning Electrical Mobility Analyzer (SEMS). The SEMS operation involves an exponential increasing voltage step (up-scan) followed by a voltage decay step (down-scan). Under up-scan operation, the mobility transfer function of the SEMS can be accurately calculated using a semi-theoretical approach, allowing for the subsequent accurate calculation of size distributions from SEMS data. The DMA transfer functions for the down scan operation are, however, not well understood and thus the down scan data is often ignored in the size distribution calculation. Using the arrival-time transfer function (ATF) approach of Dubey and Dhaniyala (2011), the DMA classification properties are investigated theoretically and a model for calculation of down-scan transfer functions as a function of DMA operating conditions is established. The details of the calculation approach and implication for size distribution calculation will be presented. Preliminary experimental validation of our calculation will also be discussed.