@@ -46,14 +46,25 @@ performance difference between pleated hydrophobic filters and electrostatic fil
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@@ -46,14 +46,25 @@ performance difference between pleated hydrophobic filters and electrostatic fil
- ASTM standards uses latex spheres. could potentially use gold particles
- ASTM standards uses latex spheres. could potentially use gold particles
- charge neutralizer recommended - but Lorena said viruses are typically polarized so maybe charge neutralization could be ignored initially
- charge neutralizer recommended - but Lorena said viruses are typically polarized so maybe charge neutralization could be ignored initially
- optical particle counter [^opc]- fancy once can be used to measure particle size with lorentz mie scattering, but it shouldn't take too much work to make our own that just counts.
- visible laser : wavelength and power determine particle size resolution, higher power --> smaller particles, limited to >100nnm (intracavity systems for smaller than that)
- photodetector placed where particles scatter light : placement could be difficult if the particles have a large area to explore, but photomulitplier tube could fix
- isokinetic sampling probes[^isokineticProbes] pull representative particle samples into the OPCs - so you don't care about area for PMT and can put the OPCs in a light box instead of the entire appartus
## shopping list
## proposed testing device
- nebulizer for aerosolization [^nebulizer_selection]
measure filtration efficiency and pressure difference with non-biological colloidal particles:
could also get away with only one OPC by adding a bypass around the test filter and a switch
## equipment needed
- nebulizer for aerosolization [^nebulizer]
- three-jet Collison nebulizer?
- three-jet Collison nebulizer?
- impinger for collection
- wet and dry thermometer / hygrometer for humidity
- wet and dry thermometer / hygrometer for humidity
- OPC : photodiodes or PMTs
- andersen sampler?? could be nice to bin different size particles - six-stage viable particle cascade impactor
- andersen sampler?? could be nice to bin different size particles - six-stage viable particle cascade impactor
- OPC would be better than andersen sampler
### Resources
### Resources
[^DIYmask]:University of Cambridge [DIY mask efficacy testing](https://www.researchgate.net/publication/258525804_Testing_the_Efficacy_of_Homemade_Masks_Would_They_Protect_in_an_Influenza_Pandemic)
[^DIYmask]:University of Cambridge [DIY mask efficacy testing](https://www.researchgate.net/publication/258525804_Testing_the_Efficacy_of_Homemade_Masks_Would_They_Protect_in_an_Influenza_Pandemic)
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@@ -64,4 +75,6 @@ performance difference between pleated hydrophobic filters and electrostatic fil
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@@ -64,4 +75,6 @@ performance difference between pleated hydrophobic filters and electrostatic fil
[^aerodynamics]:[Aerodynamic Characteristics of RNA concetration of SARS-CoV-2](https://www.biorxiv.org/content/10.1101/2020.03.08.982637v1.abstract)
[^aerodynamics]:[Aerodynamic Characteristics of RNA concetration of SARS-CoV-2](https://www.biorxiv.org/content/10.1101/2020.03.08.982637v1.abstract)
[^VFEreport]:[Nelson Laboratories: Viral Filtration Efficiency (VFE) at increased challenge level](https://gitlab.cba.mit.edu/pub/coronavirus/tracking/uploads/164d119b5a7a5751c685a6677378668a/ER_2235600_Attachment_5_Viral_Filtration_Efficiency.pdf)
[^VFEreport]:[Nelson Laboratories: Viral Filtration Efficiency (VFE) at increased challenge level](https://gitlab.cba.mit.edu/pub/coronavirus/tracking/uploads/164d119b5a7a5751c685a6677378668a/ER_2235600_Attachment_5_Viral_Filtration_Efficiency.pdf)
[^nebulizer_selection]:[Nebulizer selection from CH tech](http://chtechusa.com/Manuals/Selecting%20the%20Model%20and%20Configuration%20Instructions.pdf)
[^nebulizer]:[Nebulizer selection from CH tech](http://chtechusa.com/Manuals/Selecting%20the%20Model%20and%20Configuration%20Instructions.pdf)
