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A preliminary gas detection study was conducted on as-grown multi-walled carbon nanotubes and anodized aluminum oxide (MWNTs/AAO) template. The material demonstrated room temperature gas sensitivity and p-type semiconductor characteristics. Plasma-etched MWNTs/AAO templates were employed to construct capacitive gas sensors. The capacitances of the sensors were sensitive to both reducing and oxidizing gases at room temperature. Single-walled carbon nanotubes (SWNTs) dispersed in binder andamp;aacute;-terpineol were applied on sensor platforms to form resistive gas sensors. The sensors demonstrated excellent sensitivity to low concentrations of reducing and oxidizing gases at room temperature, which suggests the p-type semiconducting behavior of SWNTs. The sensor recovery was found to be incomplete at room temperature in flow of nitrogen and air, thus possible solutions were investigated to enhance sensor performance. The sensor operating principles and suggestions for possible future work are discussed. The room temperature and air background functionality of the sensor suggest that SWNT is a promising gas sensing material for application in ambient conditions.

This thesis proposes a methodology for determining sensitivity of building energy consumption of HVAC systems to sensor error. It is based on a series of simulations of a generic building, the model for which is based on several typical input parameters. There are a total of eight scenarios considered in this simulation. The simulation tool was developed based on Excel. The control parameters examined include room temperature, cold deck temperature, hot deck temperature, pump pressure, and fan pressure. All of the parameters considered are varied in order to analyze the sensitivity of building energy consumption to their variation. In this tool, different operation schedules for equipment, occupancy, and lighting are considered. By changing each control parameter, the sensitivity of energy use to sensor error is simulated, a regression model is generated, and the energy consumption change is expressed as a function of sensor error and outside air percentage. Two applications of this methodology are presented in this thesis. One is a SDVAV system and the other is a DDVAV system. The outside air percentage changes the trend of the sensor error curve. After the sensitivity study is discussed, some recommendations regarding the calibration intervals of the sensors are given.

In order to calculate specific impedance of cell-covered electrodes in a Equation of morphological parameters of cell per se, an ECIS model of Human Renal Epithelial Cell are created by analysis partial differential equations describing three intrinsic pathways of electrical currents in the system. Based on this cell model, this research explores how some adjustable dimensional parameters of electrode-configuration impact sensor sensitivity by changing the overall impedance contribution of electrical double layer. Namely, it includes electrode planner area, spacing between working and counter electrode and geometry of electrode, scanning frequency. Qualitative studies on how sensor sensitivity rely on configurational parameters are conducted with these parameters involved. Moreover, theoretical analysis of sensitivity by using equivalent circuit model is also carried out. As results of COMSOL simulations, special double layer electrode configurations and selectively planted cell monolayer arrangement are proposed regardless of fabrication difficulties. Accordingly, some possible strategies to make these arrangements come true are also illustrated. Finally, superior possible COMSOL simulation model is suggested and discussed for future optimization works. / 2021-05-07T00:00:00Z

A fatigue test has been performed on 7075-T651 aluminum specimens which were bonded with polyimide coated optical fibers with discrete Bragg gratings. These fibers were bonded with AE-10 strain gage adhesive. The results indicate that lower strain amplitudes do not produce cause for concern, but that larger strain amplitudes (on the order of 3500 μ) may cause some sensors to become unreliable. The strain response of acrylate coated optical fiber strain sensors bonded to aluminum specimens with AE-10 and M-Bond 200 strain gage adhesives was investigated with both axial and cantilever beam tests. These results were compared to both the strain response of conventional strain gages and to model predictions. The results indicate that only about 82.6% of the strain in the specimen was transferred through the glue line and fiber coating into the fiber. Thus, multiplying by a strain transfer factor of approximately 1.21 was sufficient to correct the optical fiber strain output. This effect was found to be independent of the adhesive used and independent of the three-dimensional profile of the glue line used to attach the fiber. Finally, this effect did not depend on whether the fiber had a polyimide or an acrylate coating. Further investigation was conducted on the feasibility of using optical fiber strain sensors for monitoring subcritical damage (such as matrix cracks) in fiber reinforced composite materials. These results indicate that an array of optical fibers which monitor the strain profile on both sides of a composite panel may be sufficient for these purposes / Master of Science