I’ve spent a long time in lab trying to optimize the protocol for streaming potential measurements. The slope of an applied pressure vs. streaming potential graph can give us the apparent zetapotential through the helmholtz-smolachowski equation. The apparent zetapotential is…
Category: NRG
Stable, Reasonable, and Reproducible Zetapotential Readings for pnc-Si Remain Just Out of Reach
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Dialysis Chip Recovery After Membrane Damage
Josh Miller came up with the idea of filling individual damaged membrane channels with PDMS so the rest of the chip could be salvaged. We worked on it this week, mostly Josh, and we developed a process using strips of…
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NSF proposal on Catalytic Membrane Reactors
I submitted a proposal last week with Tom & I as co-PI’s to NSF’s Process Reaction Engineering division in CBET. Novel Catalytic Membrane Reactor Based on Ultra-thin Palladium Film Supported on Nano-structured Inorganic Membrane I’m attaching the intro. paragraph and…
SU-8 microgrid strain measurement
Kelly & I finally succeeded in getting a measurement of the SU-8 scaffold change in size upon liftoff. Kelly, lifted off a sample (~0.5 x 2 cm) using the XeF2 dry etch and transferred the sample to a glass slide…
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Labsmith microfluidic pressure sensor (updated)
I’ve been trying to do separations with the NPN 5-slot filters by driving the solution with a syringe pump. This type of separation is required by INT for use in their cartridge. Unfortunately, at most concentrations, solutions with fluorospheres tend…
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Small Animal Model Dialysis: Nonporous and Microporous Membranes
On Wednesday Feb. 12 and Wednesday Feb. 19, limited exposure dialysis was performed on rats. In the first experiment, blood was pumped with the peristaltic blood pump through a two-chip dialysis device in an acrylic fixture. The membranes were non-porous…
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Pressure Distribution and Membrane Deflection During EO
The pressure distribution during EO is a little counter-intuitive. Assuming no back pressure, and neglecting the effects of the meniscus on either end of an EO channel, the pressure distribution relative to the (left-to-right) direction of flow must look something…
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Hydraulic Permeability
The hydraulic permeability of a membrane is the inverse of the fluid resistance normalized to the membrane area. Experimentally it is found with Where Q is the measured flow rate, is the pressure drop across the membrane and is the…
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Continued Reverse centrifuge tests
Our first attempt to “reverse” centrifuge materials using our standard 5-slot filters made of NPN from wafer 1070 are detailed in a previous post using GEN2 SEPCON assemblies. In this post we modify our method to more closely match the…
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Gate-Voltage-Dependent EO Pumping: -6 V on the Gate Changes the Pumping Rate by an Order of Magnitude
In my previous post on applying voltage to a silver-coated NPN chip, I put up a video which, if you squinted and were willing to be charitable, showed that I could modify the EO pumping behavior of the chip by…
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