Digital Commons Network^™

Cmos Based Impedance Sensing, Jinlong Gu

Masters Theses

This thesis focuses on a compact, low power circuit design for biological cell impedance sensing. Cell impedance sensing provides a new way to diagnose the cancers. Experiments done previously have shown that cancer cells have lower impedance than the normal cells, due to the thinner membrane of cancer cells. Traditional methods of cancer diagnosis require special chemicals, skilled personnel, and take long time to obtain the results. Two circuit structures are proposed in this work. One is a silicon cochlea based architecture. The other one is a current mode lock-in amplifier. Both of these two structures are able to measure …

Review And Characterization Of Gallium Nitride Power Devices, Edward Andrew Jones

Masters Theses

Gallium Nitride (GaN) power devices are an emerging technology that have only recently become available commercially. This new technology enables the design of converters at higher frequencies and efficiencies than those achievable with conventional Si devices. This thesis reviews the characteristics and commercial status of both vertical and lateral GaN power devices from the user perspective, providing the background necessary to understand the significance of these recent developments. Additionally, the challenges encountered in GaN-based converter design are considered, such as the consequences of faster switching on gate driver design and board layout. Other issues include the unique reverse conduction behavior, …

The Design And Validation Of A Wireless Bat-Mounted Sonar Recording System, Jeremy Joseph Langford

Masters Theses

Scientists studying the behavior of bats monitor their echolocation calls, as their calls are important for navigation and feeding, but scientist are typically restricted to ground-based recording. Recording bat calls used for echolocation from the back of the bat as opposed to the ground offers the opportunity to study bat echolocation from a vantage otherwise only offered to the bats themselves. However, designing a bat mounted in-flight audio recording system, (bat-tag), capable of recording the ultra-sound used in bat echolocation presents a unique set of challenges. Chiefly, the bat-tag must be sufficiently light weight as to not overburden the bat, …

Dynamic Extruder Control For Polymer Printing In Big Area Additive Manufacturing, Alex Christopher Roschli

Masters Theses

Big Area Additive Manufacturing (BAAM) is 3D Printing on a large scale and can be used to create structures on the scale of cars and houses. Scaling up 3D printing to BAAM size meant fundamentally altering the traditional fused deposition modeling process by switching from a filament to a pellet material feed. This meant switching from a stepper motor extruder to a servo driven screw extruder. While increasing the throughput of the system, this new extruder increases the overall complexity. Effective control of the system is paramount to the success of BAAM enabling it to effectively scale in speed in …

Sic Band Gap Voltage Reference For Space Applications, Charles Kenneth Roberts

Masters Theses

Electronics for space applications can experience wide temperature swings depending on orientation towards stars and duty cycle of propulsion systems. Energy on satellites primarily comes from radiological thermal generators and / or solar panels. This requires space electronic applications to be energy efficient and have high temperature tolerance. As a result, space electronic systems use high efficiency SMPS [switching mode power supplies].

Currently, there exists SiC [silicon carbide] based electronics that is state of the art for high temperature applications. Commercial manufacturers at this time produce SiC Power MOSFETs [Metal Oxide Semiconductor Field Effect Transistors], which are the switching element …