Particle Mass Monitor System

In the 3200 Particle Mass Monitor system the collection surface is a piezoelectric crystal coated with metal on two sides connected into an oscillator circuit. A piezoelectric crystal alters its shape when it is subjected to an electrical field. Thus, if an alternating electrical field is applied to such a crystal, the crystal expands and contracts in response to this electric field that is, it acts as an oscillator. The frequency at which a piezoelectric crystal oscillates is related to the mass of crystal. If the effective mass of the crystal changes, as a result of the deposition of fineparticles onto its surface, while it is oscillating, the frequency at which it oscillates shifts. This frequency shift can be related to the mass of fineparticles deposited on the crystal. The aerosol being studied is deposited onto the crystal by a combination of electrostatic forces and impaction forces. The change in oscillation fi equency is proportional to the mass of deposited aerosol fineparticles. In this instrument a reference crystal is used to allow for any drift... 

Figure 4.2 shows the complete CBMS II system. The main unit is comprised of three modules, the Biosampler Module, the Sample Introduction Module (SIM), and the Mass Spectrometer Module. The Biosampler Module houses the virtual impactor air particle concentrator and is only needed for the biological agent monitoring mode. The Sample Introduction Module contains the multiport sampling valve with its three input connections ... 

The aim of this paper is to describe the experimental and numerical techniques that, when combined, provide a procedure that enables full particle-size distribution studies of sub-micrometer emulsion systems. We then present distribution results for several oil/water emulsions to demonstrate the ability of these techniques to monitor the effect of processing variables (such as surfactant concentration) on the final emulsion. Finally, we discuss some of the problems of converting the intensity weighted distribution to a mass weighted distribution and suggest methods for minimizing or eliminating some of these problems. 

GC-MS GOME GPC GPS gas chromatography-mass spectrometry Global Ozone Monitoring Experiment gas-to-particle conversion Global Positioning System... 

Figure 1. Schematic view of CRYRING. Molecular ions are created in the ion source MINIS, accelerated and mass selected. In some cases they are further accelerated by the Radio Frequency Quadrupole (RFQ), and injected into the ring. The accelerating system is used to further increase the ion energy. Reaction products from the electron cooler section exit the ring and hit detectors located on the 0° arm. The scintillation detector, which detects neutral particles arising from collisions of the stored beam with rest gas molecules, is used as a beam monitor.

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