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Design Of Piezoresistive Mems Force And Displacement Sensors, Tyler Lane Waterfall
Design Of Piezoresistive Mems Force And Displacement Sensors, Tyler Lane Waterfall
Theses and Dissertations
MEMS (MicroElectroMechanical Systems) sensors are used in acceleration, flow, pressure and force sensing applications on the micro and macro levels. Much research has focused on improving sensor precision, range, reliability, and ease of manufacture and operation. One exciting possibility for improving the capability of micro sensors lies in exploiting the piezoresistive properties of silicon, the material of choice in many MEMS fabrication processes. Piezoresistivity—the change of electrical resistance due to an applied strain—is a valuable material property of silicon due to its potential for high signal output and on-chip and feedback-control possibilities. However, successful design of piezoresistive micro sensors requires …
Solid-State Impact-Ionization Multiplier, Hong-Wei Lee
Solid-State Impact-Ionization Multiplier, Hong-Wei Lee
Theses and Dissertations
This dissertation presents an innovative solid-state current amplifier based on impact-ionization. Unlike avalanche photodetectors which use the same amplification principle, this device can be integrated with any external current source. A discrete amplifier was built on a silicon surface using standard CMOS fabrication processes including lithography, oxidation, ion implantation, diffusion, chemical wet etching, metal deposition, annealing, and rapid thermal processing. Testing was performed by connecting the device to a silicon photodiode, indium-gallium-arsenide photodiodes, and a function generator to demonstrate its compatibility with arbitrary current sources. Current gains above 100 along with pre-amplified leakage currents of less than 10 nA were …
A Framework For An Implantable Wireless Pressure And Volume Sensor Focusing On The Diagnosis And Treatment Of Shunt Failure In Hydrocephalus Patients, Donald Monte Wichern
A Framework For An Implantable Wireless Pressure And Volume Sensor Focusing On The Diagnosis And Treatment Of Shunt Failure In Hydrocephalus Patients, Donald Monte Wichern
Theses and Dissertations
The framework for a permanently implantable wireless compliance sensor was developed and validated using laboratory experiments. The proposed sensor would measure the intracranial pressure and fluid volume in the brain and return this information to a monitoring device. The designed sensor received power remotely from the monitoring device negating the need for an implanted power source. Impedance measurement estimation techniques were suggested, studied and applied to the compliance sensing system. A new impedance measurement technique, accounting for multiple variability in the domain, was developed. An extensive simulation environment was designed and used to develop the laboratory experiments and hardware. The …
Novel Conceptual Design And Anlysis Of Polymer Derived Ceramic Mems Sensors For Gas Turbine Environment, Narasimha Nagaiah
Novel Conceptual Design And Anlysis Of Polymer Derived Ceramic Mems Sensors For Gas Turbine Environment, Narasimha Nagaiah
Electronic Theses and Dissertations
Technical challenges for developing micro sensors for Ultra High Temperature and turbine applications lie in that the sensors have to survive extremely harsh working conditions that exist when converting fuel to energy. These conditions include high temperatures (500-1500°C), elevated pressures (200-400 psi), pressure oscillations, corrosive environments (oxidizing conditions, gaseous alkali, and water vapors), surface coating or fouling, and high particulate loading. Several technologies are currently underdeveloped for measuring these parameters in turbine engines. One of them is an optical-based non-contact technology. However, these nondirective measuring technologies lack the necessary accuracy, at least at present state. An alternative way to measure …
Intrusion Detection In Wireless Sensor Networks, Hong Nhung Nguyen
Intrusion Detection In Wireless Sensor Networks, Hong Nhung Nguyen
Electronic Theses and Dissertations
There are several applications that use sensor motes and researchers continue to explore additional applications. For this particular application of detecting the movement of humans through the sensor field, a set of Berkley mica2 motes on TinyOS operating system is used. Different sensors such as pressure, light, and so on can be used to identify the presence of an intruder in the field. In our case, the light sensor is chosen for the detection. When an intruder crosses the monitored environment, the system detects the changes of the light values, and any significant change meaning that a change greater than …