tools-for-surface-treatment-silicon-planar-intracortical

Tools for Surface Treatment of Silicon Planar Intracortical Microelectrodes

Intracortical microelectrodes hold great therapeutic potential. But they are challenged with significant performance reduction after modest implantation ...

Case Western Reserve University

Louis Stokes Cleveland Department of Veterans Affairs Medical Center

This paper presents a set of system validation experiments that can be used to qualify either static or flow experimental systems for gathering tracer photophysical data or conducting laser diagnostics at high pressure and temperature in order to establish design and operation limits and reduce uncertainty in data interpretation. Tests demonstrated here quantify the effect of tracer absorption at the test cell walls, stratification, photolysis, pyrolysis, adequacy of mixing and seeding, and reabsorption of laser light using acetone as the tracer and 282 nm excitation. Results show that acetone exhibits a 10% decrease in fluorescence signal over 36 000 shots at 127.4 mJ/cm, and photolysis is negligible below 1000 shots collected. Meanwhile, appropriately chosen gas residence times can mitigate risks due to pyrolysis and inadequate mixing and seeding; for the current work 100 ms residence time ensured <0.5% alteration of tracer number density due to thermal destruction. Experimental results here are compared to theoretical values from the literature.

System Validation Experiments for Obtaining Tracer Laser-Induced Fluorescence Data at Elevated Pressure and Temperature.

This paper provides new data at constant pressure, variable temperature and constant temperature, variable pressure over the range of temperature (295-750 K) and pressure (0.5-40 atm), in air and nitrogen bath gases at both constant number density and constant mole fraction needed to enable acetone laser-induced fluorescence (LIF) as a diagnostic tool in an elevated temperature and pressure environment. Results clearly indicate that the effect of elevated pressure on the temperature sensitivity of acetone LIF is negligible when the excitation wavelength is chosen near the absorption maximum, making acetone LIF ideal for measuring temperature fields in high-pressure systems. The data also show that the temperature sensitivity of fluorescence is relatively insensitive to changes in pressure at 282 nm excitation. Furthermore, at 282 nm, fluorescence per mole fraction can be used to extract temperature while fluorescence per molecule is relatively insensitive to temperature, making it optimal for concentration or pressure measurements.

Article	Year
System Validation Experiments for Obtaining Tracer Laser-Induced Fluorescence Data at Elevated Pressure and Temperature. Applied spectroscopy\| PubMed ID: 29164904	2018
Acetone Tracer Laser-Induced Fluorescence (LIF) at 282 nm Excitation as a Diagnostic Tool in Elevated Pressure and Temperature Systems. Applied spectroscopy\| PubMed ID: 30777449	2019

Gaurav Mittal

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