Low pressure impactor measurements with duplicated stages to minimize particle bounce effects

1995 ◽  
Vol 26 ◽  
pp. S785-S786
Author(s):  
U Tapper ◽  
T Valmari ◽  
T Lind ◽  
E.I Kauppinen
Keyword(s):  
Low Pressure ◽  
Particle Bounce

scholarly journals Utilizing an electrical low-pressure impactor to indirectly probe water uptake via particle bounce measurements

2021 ◽  
Vol 14 (12) ◽  
pp. 7565-7577
Author(s):  
Kevin B. Fischer ◽  
Giuseppe A. Petrucci
Keyword(s):  
Relative Humidity ◽  
Water Uptake ◽  
Geometric Mean ◽  
Complex Viscosity ◽  
Organic Aerosol ◽  
Low Pressure ◽  
Multi Stage ◽  
Volatile Organic ◽  
Particle Bounce ◽  
Phase Behaviors

Abstract. Secondary organic aerosol (SOA), formed through oxidation of volatile organic compounds (VOCs), displays complex viscosity and phase behaviors influenced by temperature, relative humidity (RH), and chemical composition. Here, the efficacy of a multi-stage electrical low-pressure impactor (ELPI) for indirect water uptake measurements was studied for ammonium sulfate (AS) aerosol, sucrose aerosol, and α-pinene-derived SOA. All three aerosol systems were subjected to greater than 90 % chamber relative humidity, with subsequent analysis indicating persistence of particle bounce for sucrose aerosol of 70 nm (initial dry diameter) and α-pinene-derived SOA of number geometric mean diameters between 39 and 136 nm (initial dry diameter). On the other hand, sucrose aerosol of 190 nm (initial dry diameter) and AS aerosol down to 70 nm (initial dry diameter) exhibited no particle bounce at elevated RH. Partial drying of aerosol within the lower diameter ELPI impaction stages, where inherent and significant RH reductions occur, is proposed as one explanation for particle bounce persistence.

scholarly journals Utilizing an Electrical Low Pressure Impactor to Indirectly Probe Water Uptake via Particle Bounce Measurements 

2021 ◽  
Author(s):  
Kevin B. Fischer ◽  
Giuseppe A. Petrucci
Keyword(s):  
Relative Humidity ◽  
Water Uptake ◽  
Geometric Mean ◽  
Complex Viscosity ◽  
Organic Aerosol ◽  
Low Pressure ◽  
Multi Stage ◽  
Volatile Organic ◽  
Particle Bounce ◽  
Phase Behaviors

Abstract. Secondary organic aerosol (SOA), formed through oxidation of volatile organic compounds (VOCs), display complex viscosity and phase behaviors influenced by temperature, relative humidity (RH), and chemical composition. Here, the efficacy of a multi-stage electrical low pressure impactor (ELPI) for indirect water uptake measurements was studied for ammonium sulfate (AS) aerosol, sucrose aerosol, and α-pinene derived SOA. All three aerosol systems were subjected to greater than 90 % chamber relative humidity, with subsequent analysis indicating persistence of particle bounce for sucrose 10 aerosol of 70 nm (initial dry diameter) and α-pinene derived SOA of number geometric mean diameters between 39 nm and 136 nm (initial dry diameter). On the other hand, sucrose aerosol of 190 nm (initial dry diameter) and AS aerosol down to 70 nm (initial dry diameter) exhibited no particle bounce at elevated RH. Partial drying of aerosol within the lower diameter ELPI impaction stages, where inherent and significant RH reductions occur, is proposed as one explanation for particle bounce persistence.

Effects of Electrical Discharges in Low Pressure Gases on the Morphology of Polyethylene Crystals

1974 ◽  
Vol 32 ◽  
pp. 544-545
Author(s):  
L.H. Bolz ◽  
D.H. Reneker
Keyword(s):  
Power Distribution ◽  
Electrical Discharge ◽  
Dielectric Breakdown ◽  
Ionic Species ◽  
Low Pressure ◽  
Polymer Surfaces ◽  
Electrical Discharges ◽  
Adhesive Bonds ◽  
Power Distribution Lines ◽  
Modification Of The Surface

The attack, on the surface of a polymer, by the atomic, molecular and ionic species that are created in a low pressure electrical discharge in a gas is interesting because: 1) significant interior morphological features may be revealed, 2) dielectric breakdown of polymeric insulation on high voltage power distribution lines involves the attack on the polymer of such species created in a corona discharge, 3) adhesive bonds formed between polymer surfaces subjected to such SDecies are much stronger than bonds between untreated surfaces, 4) the chemical modification of the surface creates a reactive surface to which a thin layer of another polymer may be bonded by glow discharge polymerization.

Field ion microscopy

1988 ◽  
Vol 46 ◽  
pp. 434-435
Author(s):  
Gert Ehrlich
Keyword(s):  
Low Temperature ◽  
Sample Surface ◽  
Low Pressure ◽  
Radius Of Curvature ◽  
Field Ion Microscopy ◽  
Phosphor Screen ◽  
Ion Microscopy ◽  
Field Ion Microscope

The field ion microscope, devised by Erwin Muller in the 1950's, was the first instrument to depict the structure of surfaces in atomic detail. An FIM image of a (111) plane of tungsten (Fig.l) is typical of what can be done by this microscope: for this small plane, every atom, at a separation of 4.48Å from its neighbors in the plane, is revealed. The image of the plane is highly enlarged, as it is projected on a phosphor screen with a radius of curvature more than a million times that of the sample. Müller achieved the resolution necessary to reveal individual atoms by imaging with ions, accommodated to the object at a low temperature. The ions are created at the sample surface by ionization of an inert image gas (usually helium), present at a low pressure (< 1 mTorr). at fields on the order of 4V/Å.

Low pressure improves ink jets

Nature ◽  
2005 ◽  
Author(s):  
Philip Ball
Keyword(s):  
Low Pressure
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