Browsing by Author "Anderson, Evan"
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Item Detection of Ice and De-Icing/Anti-Icing Fluids on Aircraft Surfaces Using Time Domain Reflectometry(2014-05) Anderson, EvanTime domain reflectometry is a practical and effective way to detect ice, frost, moisture, anti-icing/de-icing aircraft fluids (ADAFs), and mixtures of each on aircraft surfaces. Using this method, a passive sensor is placed at the end of a transmission line. A fast rise-time pulse excites the transmission line and is reflected from the sensor upon its arrival at the end of the line. The detailed shape of the reflected waveform depends on the dielectric properties of the fluid in contact with the sensing electrodes. Multiple sensors were constructed and tested to determine the suitability and reliability of varying designs. A software protocol was also developed to detect phase transitions and alert pilots with a binary response that indicates a safe or hazardous condition. In effect, this system would help reduce the volume of ADAFs applied and increase the safety of air travel.Item Development of Improved Ion-Selective and Reference Electrodes for In Situ Monitoring of Ion Concentrations(2019-07) Anderson, EvanThis dissertation is focused on the application of electrochemistry for the fundamental understanding, development, and application of electrochemical sensors. In particular, my research focused on the development and understanding of reference electrodes and ion-selective electrodes for potentiometric sensing applications. Recently, following the needs of point-of-care and wearable sensors, electrode designs have transitioned from bulky devices with an aqueous inner filling solution (e.g. pH electrodes) to planarizable solid-contact electrodes. However, unless their polymeric sensing and reference membranes are held in place mechanically, delamination of the physically adhering membranes limits sensor lifetime, as even minimal external mechanical stress or thermal expansion can result in membrane delamination and, thereby, device failure. To address this problem, we designed a sensing platform based on inexpensive polymers to which membranes are attached covalently through photopolymerization. Even extreme mechanical stress does not result in the delamination of the sensing and reference membranes from the underlying polymer, which results in electrodes that exhibit much improved long-term performance and greatly reduced size. This method of sensor preparation is broadly applicable to a wide range of electrode types and allows for long-term measurements of numerous ions that are of environmental and medical significance. Moreover, the applicability of these ion-selective electrodes for long-term measurements requires reference electrodes that also provide stable responses. Reported here are two types of improved reference electrodes based on capillaries and ionic liquids.