The development and fabrication of silicon-based phononic band gap crystals has been gaining interest since phononic band gap crystals have implications in fundamental science and display the potential for application in engineering by providing a relatively new platform for the realization of sensors and signal processing elements. The seminal study of phononic band gap phenomenon for classical elastic wave localization in structures with periodicity in two- or three-physical dimensions occurred in the early 1990’s. Micro-integration of silicon devices that leverage this phenomenon followed from the mid-2000’s until the present. The reported micro-integration relies on exotic piezoelectric transduction, phononic band gap crystals that are etched into semi-infinite or finite-thickness slabs which support surface or slab waves, phononic band gap crystals of numerous lattice constants in dimension and phononic band gap crystal truncation by homogeneous mediums or piezoelectric transducers. The thesis reports, to the best of the author's knowledge, for the first time, the theory, design methodology and experiment of an electrostatically actuated silicon-plate phononic band gap quasi-crystal architecture, which may serve as a platform for the development of a new generation of silicon-integrated sensors, signal processing elements and improved mechanical systems. Electrostatic actuation mitigates the utilization of piezoelectric transducers and provides action at a distance type forces so that the phononic band gap quasi-crystal edges may be free standing for potentially reduced anchor and substrate mode loss and improved energy confinement compared with traditional surface and slab wave phononic band gap crystals. The proposed phononic band gap quasi-crystal architecture is physically scaled for fabrication as MEMS in a silicon-on-insulator process. Reasonable experimental verification of the model of the electrostatically actuated phononic band gap quasi-crystal architecture is obtained through extensive dynamic harmonic analysis and mode shape topography measurements utilizing optical non-destructive laser-Doppler velocimetry. We have utilized our devices to obtain fundamental information regarding novel transduction mechanisms and behavioral characteristics of the phononic band gap quasi-crystal architecture. Applicability of the phononic band gap quasi-crystal architecture to physical temperature sensors is demonstrated experimentally. Vibration stabilized resonators are demonstrated numerically.

This study concerns with the testing methods for mechanical characterization at micron scale. The need for the study arises from the fact that the mechanical properties of materials at micron scale differ compared to their bulk counterparts, depending on the microfabrication method involved. Various test structures are designed according to the criteria specified in this thesis, and tested for this purpose in micron scale. Static and fatigue properties of the materials are aimed to be extracted through the tests. Static test structures are analyzed using finite elements method in order to verify the results. Test structures were fabricated by deep reactive ion etching of 100 &micro / m thick (111) silicon and electroplating 18 &micro / m nickel layer. Performance of the test structures are evaluated based on the results of tests conducted on the devices made of (111) v silicon. According to the results of the tests conducted on (111) silicon structures, elastic modulus is found to be 141 GPa on average. The elastic modulus of electroplated nickel is found to be 155 GPa on average, using the same test structures. It is observed that while the averages of the test results are acceptable, the deviations are very high. This case is related to fabrication faults in general. In addition to the tests, a novel computer script utilizing image processing is also developed and used for determination of the deflections in the test structures.

The development of a robotic slit-lamp for remote ophthalmology is the primary purpose of this work. In addition to novel mechanical designs and implementation, it was also a goal to develop a control system that was flexible enough to be adapted with minimal user adjustment to various styles and configurations of slit-lamps. The system was developed with intentions of commercialization, so common hardware was used for all components to minimize the costs. In order to improve performance using this low-cost hardware, investigations were made to attempt to achieve better performance by applying control theory algorithms in the system software. Ultimately, the controller was to be flexible enough to be applied to other areas of human-robot interaction including pediatric rehabilitation via the use of humanoid robotic aids. This application especially requires a robust controller to facilitate safe interaction. Though all of the prototypes were successfully developed and made to work sufficiently with the control hardware, the application of advanced control did not yield notable gains as was hoped. Further investigations were made attempting to alter the performance of the control system, but the components selected did not have the physical capabilities for improved response above the original software implemented. Despite this disappointment, numerous novel advances were made in the area of teleoperated ophthalmic technology and pediatric physical rehabilitation tools. This includes a system that is used to remote control a slit-lamp and lens for examinations and some laser procedures. Secondly, a series of of humanoid systems suitable for both medical research and therapeutic modeling were developed. This included a robotic face used as an interactive system for ophthalmic testing and training. It can also be used as one component in an interactive humanoid robotic system that includes hands and arms to allow use of teaching sign language, social skills or modeling occupational therapy tasks. Finally, a humanoid system is presented that can serve as a customized surrogate between a therapist and client to model physical therapy tasks in a realistic manner. These systems are all functional, safe and low-cost to allow for feasible implementation with patients in the near future.

abstract: Harsh environments have conditions that make collecting scientific data difficult with existing commercial-off-the-shelf technology. Micro Electro Mechanical Systems (MEMS) technology is ideally suited for harsh environment characterization and operation due to the wide range of materials available and an incredible array of different sensing techniques while providing small device size, low power consumption, and robustness. There were two main objectives of the research conducted. The first objective was to design, fabricate, and test novel sensors that measure the amount of exposure to ionizing radiation for a wide range of applications including characterization of harsh environments. Two types of MEMS ionizing radiation dosimeters were developed. The first sensor was a passive radiation-sensitive capacitor-antenna design. The antenna's emitted frequency of peak-intensity changed as exposure time to radiation increased. The second sensor was a film bulk acoustic-wave resonator, whose resonant frequency decreased with increasing ionizing radiation exposure time. The second objective was to develop MEMS sensor systems that could be deployed to gather scientific data and to use that data to address the following research question: do temperature and/or conductivity predict the appearance of photosynthetic organisms in hot springs. To this end, temperature and electrical conductivity sensor arrays were designed and fabricated based on mature MEMS technology. Electronic circuits and the software interface to the electronics were developed for field data collection. The sensor arrays utilized in the hot springs yielded results that support the hypothesis that temperature plays a key role in determining where the photosynthetic organisms occur. Additionally, a cold-film fluidic flow sensor was developed, which is suitable for near-boiling temperature measurement. Future research should focus on (1) developing a MEMS pH sensor array with integrated temperature, conductivity, and flow sensors to provide multi-dimensional data for scientific study and (2) finding solutions to biofouling and self-calibration, which affects sensor performance over long-term deployment. / Dissertation/Thesis / Ph.D. Engineering 2013

The non-contact nature of magnetic actuation makes it useful in a variety of microscale applications, from microfluidics and lab-on-a-chip devices to classical MEMS or even microrobotics. Ferromagnetic materials like nickel are particularly attractive, because they can be easily deposited and patterned using traditional lithography-based microscale fabrication methods. However, the response of ferromagnetic materials in a magnetic field can be difficult to predict. When placed in a magnetic field, high magnetization is induced in these ferromagnetic materials, which in turn generates force and/or torque on the ferromagnetic bodies. The magnitude and direction of these forces are highly dependent on the type of material used, the volume and aspect ratio of the ferromagnetic material, as well as the spatial distribution and magnitude of the magnetic field. It is important to understand these complex interactions in order to optimize force and torque generated, particularly given common limitations found in microfabrication, where it is often challenging to deposit large volumes of ferromagnetic material using conventional microdeposition methods, and power availability is also often limited, which in turn limits the ability to generate strong electromagnetic fields for actuation. This work represents a theoretical analysis and experimental validation in macro scale to determine best practices when designing ferromagnetic actuators for microscale applications. Specifically, the use of nickel thin film prisms actuated in spatially uniform electromagnetic fields. These constraints were chosen because uniform magnetic fields can be readily generated with a simple and inexpensive Helmholtz coil design, and the uniformity makes actuation force independent of location, minimizing the need for spatial precision in devices. Nickel can also be easily deposited using evaporation or sputtering, generally in forms of thin-films.

A method for tuning the spring rate and damping rate of a mountain bike suspension based on a data-driven procedure is presented. The design and development of a custom data acquisition system, known as the MTB~DAQ, capable of measuring acceleration data at the front and rear axles of a bike are discussed. These data are input into a model that is used to calculate the vertical acceleration and pitching angular acceleration response of the bike and rider. All geometric and dynamic properties of the bike and rider system are measured and built into the model. The model is tested and validated using image processing techniques. A genetic algorithm is implemented with the model and used to calculate the best spring rate and damping rate of the mountain bike suspension such that the vertical and pitching accelerations of the bike and rider are minimized for a given trail. Testing is done on a variety of different courses and the performance of the bike when tuned to the results of the genetic algorithm is discussed. While more fine tuning of the model is possible, the results show that the genetic algorithm and model accurately predict the best suspension settings for each course necessary to minimize the vertical and pitching accelerations of the bike and rider.

This Thesis describes the design, assembly, programming, and evaluation of the BLDS-M-RAKE, the newest addition to the family of devices called the Boundary Layer Data System (BLDS). The BLDS-M-RAKE is a continuation of the BLDS-M series of devices, a modular approach with updated electronics for boundary layer measurements. The BLDS-M-RAKE records data from a number of sensors, intended to be routed to an array of probes, or rake. Through preliminary testing, a new flexible manifold design from molded silicone and the hardware used on the RFduino development boards from the BLDS-M proof-of-concept modules were validated for use in the final prototype design. A PCB was designed to house a Simblee System on a Chip (SOC), 11 Honeywell pressure sensors, a microUSB socket, a microSD socket, a DC-DC boost regulator, and two AAA cells. The SOC was then programmed in C++ with the Arduino IDE. The Simblee was programmed to prompt a user over a serial monitor to confirm test parameters from a configuration file and then coordinates the reading and recording of sensor data during a flight test. Problems after assembly did not allow a full evaluation of the board, but the following was concluded: the sleeping board current draw was less than 3 mA and the peak current draw was less than 30 mA. The sensors could be sampled at 100 Hz and recorded to the microSD card. The flexible manifolds molded from silicone are viable for future designs.

Observing the dynamic interaction between stars and their close stellar neighbors is key to establishing the stars’ orbits, masses, and other properties. Our ability to visually discriminate nearby stars is limited by the power of our telescopes, posing a challenge to astronomers at small observatories that contribute to binary star surveys. Masks placed at the telescope aperture promise to augment the resolving power of telescopes of all sizes, but many of these masks must be manually and repetitively reoriented about the optical axis to achieve their full benefits. This paper introduces a design concept for a mask rotation mechanism that can be adapted to telescopes of different types and proportions, focusing on an implementation for a Celestron C11 Schmidt–Cassegrain optical tube assembly. Mask concepts were first evaluated using diffraction simulation programs, later manufactured, and finally tested on close double stars using a C11. An electronic rotation mechanism was designed, produced, and evaluated. Results show that applying a properly shaped and oriented mask to a C11 enhances contrast in images of double star systems relative to images captured with the unmasked telescope, and they show that the rotation mechanism accurately and repeatably places masks at target orientations with minimal manual effort. Detail drawings of the mask rotation mechanism and code for the software interface are included.

Fried foods are delicious and enjoyed by almost everyone. However, they are not the healthiest foods to eat because of the amount of oil they contain. This thesis, sponsored by Moaero Company founder, Mr. Harrish Bhutani, intends to determine whether a simply designed centrifuge system can remove a reasonable amount of oil from fried foods after it has been deep fried without adversely affecting the texture of the fried food. Due to a large variety in the texture as well as the type of fried foods, and in order to keep the scope of this thesis more focused and feasible, the focus of this investigation will be French fries. Three variables are tested: the type of fry, the angular velocity of the centrifuge, and the time spent in the centrifuge. Multiple designs for the centrifuge system were made on SolidWorks. Engineer Equation Solver (EES) was used to aid steady state and transient heat transfer calculations. Minitab was used for statistical analysis. The impact of various parameters on the change in mass of the French fries, as a measure for evaluating the oil content, were studied. The results indicate whether a centrifuge will remove a reasonable amount of oil while also considering the integrity of the fries. The study concludes that centrifugation is be a cost-effective method for removing oil from fried foods.

From the nano scale to the macro scale, large models are used to simulate and predict the responses of dynamic systems. The construction and evaluation of such models, often in the form of finite element models, require tremendous computational resources and time. Due to this large computational endeavor, it is paramount to learn as much as possible from the models and their solutions. In this work, analyses and methods for efficiently deriving significant knowledge of damped systems from models and their solutions are presented. Of primary interest to this work is the analysis of damped structures. Damping, the means by which energy is dissipated, often adds an additional layer of complexity to finite element models and any subsequent analyses. This added complexity is due to the relative complexity of many damping models and their accompanying computational burden. Furthermore, on the micro and nano scale, a variety of damping mechanisms, each with their own unique set of physics, may be present. The research presented in this work is organized in two parts. The first part presents methods for deriving knowledge from models and their solutions. Here, the developed methods perform approximate yet highly efficient analysis on the matrices and solution vectors of finite element models. In this work, methods utilizing the Neumann series approximation are presented. These methods efficiently predict how the response of a structure depends on its damping or any other input model parameter. Additionally, a method for analyzing the spatial dependence of damping with the use of loss factor images is presented. Research presented in the second part derives knowledge solely from solutions of models. In this part, it is assumed that the matrices of the models are not available, and therefore analysis is restricted to the solution itself. Here, research is focused on the analyses of structures on the micro and nano scale. Specifically, micro and nano beams surrounded by a viscous compressible fluid are analyzed. The dynamic responses of the structure and the surrounding fluid are analyzed to determine the prominent damping mechanisms. Here, results from 2--Dimensional analytical models and 3--Dimensional finite element models are complemented by experimental measurements to analyze damping due to viscous dissipation and acoustic radiation.