As the second leading cause of cancer death worldwide, gastric cancer is a global issue. Screening programs have had a significant impact on reducing mortality but are unavailable to most people in in low- and middle-income nations. In this document, we introduce a platform designed to enable inexpensive gastric screening programs to take place in remote areas of low- and middle income nations. The system consists of a swallowable endoscopic capsule connected to an external water distribution system by a multi-channel soft tether. The expulsion of pressurized water from the capsule's fluid exhaust ports allows the user to maneuver the capsule and orient the on-board endoscopic camera within the patient. Upon completion of a cancer screening procedure, the outer shell of the capsule and the soft tether can be disposed, while the endoscopic camera is reclaimed without needing further reprocessing or sterilization. Experimental assessment was accomplished through a set of bench trials, ex vivo analysis, and in vivo feasibility validation. During the ex vivo trials, the platform was able to visualize landmarks that are typically observed during a gastric cancer screening procedure in less than eight minutes. With the system's compact footprint, the minimal cost of the disposable parts, and the possibility of running on relatively available and inexpensive resources, the platform can potentially widen gastric cancer screening programs in low- and middle-income nations.

High speed turbulent flames can be found in most aerospace propulsion devices. In order to understand the behavior and phenomenological nature of combustion in these devices time resolved, non-invasive, in situ laser diagnostic measurements are needed. In this dissertation, laser diagnostics are used to study freely propagating turbulent premixed flames, and non premixed flames in a model scramjet combustor. In addition, a new laser method is developed to measure velocity profiles in reacting regions without seed particles. Premixed turbulent flames have been studied extensively over burner stabilized flames. However, the flame propagation in these burners is usually affected by the burner itself resulting in a geometric dependent propagation. Therefore, a fundamental understanding of the interaction between turbulence and premixed flames is obscured. Alternatively, spherically propagating flames (also known as flame kernels) that do not have these geometric dependencies can be studied using flame bombs. While flame bomb studies have been very successful in elucidating the interaction between turbulence and premixed flames, they typically have limited optical access and a mean radial inflow which can inhibit flame propagation. Therefore, a new means of studying flame kernels is described using a turbulent wind tunnel where flame kernels are allowed to freely propagate downstream. The results obtained in this new device are compared with traditional flame bomb measurements. The reaction progress of a non-premixed combustion inside a cavity-piloted scramjet combustor was determined by measuring all major species and temperature using spontaneous UV Raman scattering. A 70% CH4/30% H2 fuel blend was used to approximate the reactivity of liquid jet fuels, and minimize the number of Raman spectral lines to ensure tractable data sets. Inside the cavity, H2 fuel quickly burnt off while the CH4 and CO persisted until the fuel path reached the cavity shear layer. Finally, a new molecular tagging velocimetry method of obtaining non-seeded velocity measurements inside a reaction zone is described. This method uses a two-photon process to dissociate H2O and create vibrationally excited OH photofragments which can then be differentiated from flame generated OH radicals that are predominately in the vibrational ground state to make single-shot velocity measurements.

This dissertation describes the development of a portable, hand-held tonometer for measurement of the intraocular pressure through the eyelid. The primary use of such device will be by people diagnosed with the eye disease glaucoma. Glaucoma is the second leading cause of blindness in the world and is asymptomatic to the patient in its early stages. This allows it to remain undiagnosed for prolonged periods, causing irreversible damage to the affected person's vision. Elevated intraocular pressure is the main risk factor associated with the development of glaucoma, and is currently the only symptom that is treatable for the slowing down or stopping of the progression to blindness caused by the disease. The effectiveness of the medications or procedures aimed at reducing the pressure to below risk levels is currently monitored through visits to the ophthalmologists' offices, which makes the frequent monitoring of the pressure inconvenient, expensive and sometimes impossible. Due to the variation of the pressure throughout the day and during different activities or food and beverage intake, the portability of the device is important in order to allow the user to carry it with them and take measurements as frequent as needed. The option to perform the measurement through the eyelid avoids direct contact with the eye, eliminating possible discomfort, the use of anesthetics, and the risk of contamination.Several designs and measuring concepts are evaluated using a custom made pressure regulation system. A series of prototypes have been built and tested and the results are reported in the respective sections of the dissertation. The final concept selected for the measurement technique was based on multiple force probe indentation and a custom MEMS-based force sensor for it was designed and tested.The main contributions of this dissertation are the design, fabrication and test of the prototype devices and the MEMS force sensors. The obtained results and experience described here can serve as a platform for further optimization and improvement of the device, and eventual development of a prototype capable of performing clinical research studies and passing FDA approval for home and clinical use.

In complex organisms, the combined actions of multiple cells enable higher order functions while using only the building blocks of individual cells. Understanding the regulation of groups of cells is thus critical in order to uncover how single cells combine to produce higher levels of functionality. One principle input which regulates cell behavior is the surrounding cellular environment, many aspects of which are inherently nano- or microscale in nature. A system has therefore been developed which can replicate important micro- and nanoscale aspects of the cellular environment by providing inputs to groups of cells which mimic those found physiologically. This has been accomplished by developing a cell sensitive plasma surface patterning technique termed plasma lithography that produces area selective functional group modification to provide cell attachment guidance at sizes ranging from 100 nm to millimeters. This surface patterning system has further been coupled with additional inputs such as chemical and mechanical stimulation in order to investigate several areas where higher order functionality is observed based upon interactions of single cells. These investigations include study of an autocatalytic feedback mechanism which is involved in muscle formation and the behavior of small messenger signaling in networks of vascular cells.

Shape memory polymers are smart materials that can be trained to hold a temporary shape through programming and regain their original shape upon heating. Since there discovery in the 1960s, much research has been devoted to the study of these polymers. Of particular interest in recent years is the study of self-healing shape memory polymers. In a previous study, it has been shown that in order for efficient healing to take place in self-healing shape memory polymers, confinement during healing is essential. Moreover, a two-step close-then-heal (CTH) approach to healing was suggested. It was shown that use of this CTH method on a shape memory particulate composite provided both structural (macro) and microscopic healing of the material. The present study aimed to further investigate the influence on confinement levels and local heating on healing efficiencies of a polystyrene based shape memory polymer with 6% by volume of thermoplastic particle additives (copolyester). After fabrication of the composite, the glass transition temperature was determined by DSC analysis of the material. Cylindrical specimens measuring 120 mm long and with a 10 mm diameter were used for testing. Each specimen underwent thermomechanical programming to a pre-strain level of 10 %. After programming each specimen then underwent a three-point flexural test to complete failure. The broken specimens were then healed at varying levels of confinement and at varying healing stresses. In this study three levels of confinement and three healing stresses were investigated: 50 %, 75 %, 100 % and 0 MPa, 7 MPa, and 12 MPa respectively. At least two specimens were used for each test. After healing the specimens again underwent a three-point flexural test to complete failure. Comparison of the post-programming ultimate strength to the post-healing ultimate strength provided a means of calculating the healing efficiency of the material under each testing condition. It was shown that as the level of confinement increased, so did the healing efficiency of the material. This was attributed mostly to the higher recovery stress produced by more activation of the polymer chains as more of the material is confined and heated. Also, in the case of 75 and 100 % confinement, the healing efficiency showed a steady increase as the healing stress applied increased. However, this trend was not seen in the case of 50 % confinement. The maximum average healing efficiency seen was 91.02 % and was obtained through healing at the maximum confinement level (100 %) and the maximum applied healing stress (12 MPa).

MECHANICAL ENGINEERING Mechano-Electrochemistry of Nickel Titanium Alloy Deanna Schauben Thesis under the direction of Professor Cary L. Pint The fields of strain engineering and mechano-electrochemistry have recently emerged to explore the relationship between strain and electrochemical properties, particularly as they pertain to corrosion. NiTi is an ideal candidate for investigating this relationship due to its superelastic and shape memory properties. Here, an in-situ mechano-electrochemical cell is designed and implemented to obtain the open circuit voltage response of NiTi during straining. Of particular interest is the OCV behavior during the stress-induced martensitic transformation, which is both immediate and dramatic. A survey of OCV response during straining as well as the steady-state response after straining was performed for samples deformed to different percentages of strain at two different strain rates. The steady-state response is permanently changed by up to 44.8 mV only when strain is halted within the SIM plateau, and the magnitude of OCV change increases by a factor of about 2.5-2.9 with a strain rate increase by a factor of 5. These results point to an energetic mechanism of the SIM transformation that is yet to be investigated.

<p> This thesis is a study of bifurcation trees of periodic motions in a parametric Duffing oscillator. The bifurcation trees from period-1 to period-4 motions are investigated by a semi-analytic method. For the semi-analytic method, the discretization of differential equations of nonlinear dynamical systems is obtained to attain the implicit mapping structure. Following the development of implicit mapping structure, the periodic nodes of periodic motions are computed. The stability and bifurcation conditions are carried out by the eigenvalue analysis. For a better understanding of nonlinear behaviors of periodic motions, the harmonic frequency-amplitude characteristics are presented by the finite Fourier series. Numerical simulations are illustrated to verify the analytical predictions. Based on the comparison of numerical and analytical result, the trajectory, time history, harmonic amplitude and harmonic phase plots of period-1 to period-4 motions are completed.</p>

<p> The Southwest Navajo Nation (SNN) in northeastern Arizona has to deal with poor water quality from regional wells. The people in the Black Falls area of the SNN, have to haul about 10 gallons per capita per day (gpcd) of potable water for household, driving an average of 30 miles per trip, costing at least $30 per 1,000 gallons of potable water and livestock water at a much greater cost. To put this cost in perspective, the people in nearby Flagstaff Arizona pay $3.85 per 1,000 gallons of potable water. The residents of the Black Falls area lack available, efficient, and affordable electricity or any kind of inter-residence electric infrastructure.</p><p> Through an agreement between the University of Arizona (UA) and the U.S. Bureau of Reclamation (Reclamation) a pilot-scale solar energy based desalination system was deployed in the Black Falls area in 2014 with a goal to produce 100 gallons of fresh water per day from brine water pumped from the Coconino Sandstone aquifer of the Little Colorado River basin. The water desalination facility operates as an isolated system, in semi-arid climate (Koppen climate classification BSk), located an elevation of 1,470 m above sea level, with an annual average wind speed of 4.77 <i>m/s</i> at 21.3 <i>m</i> hub height and a solar annual average global horizontal irradiance (GHI) of 5.23<i> kWh/m2/day</i>. By 2015 the desalination research facility was functioning, powered by solar energy (electric and thermal) and backed-up by a propane gas generator. The technology initially selected for testing was sweeping gas membrane distillation (SGMD), in which water is evaporated across the membrane interface between brine and carrier gas in order to purify the water. Operating experience demonstrated that the solar energy supply was insufficient to produce the desired amount of desalinated water and that associated costs (equipment and operation) were high. Northern Arizona University began working with UA in 2015, and undertook a detailed thermodynamic and energy analysis of the desalination system. The energy analysis reveals that the SGM desalination system at 78.8 <i>L/day</i> (20.8 <i> gal/day</i>) requires 26.8 <i>kWh/day</i> (power of 3.35 <i> kW</i>) of electricity and 85.8 <i>kWh/day</i> of thermal energy (power of 10.7 <i>kW</i>). In addition, this study reveals that the CPV is not capable of providing the required thermal energy and electrical energy (50% and 15% deficits). The deficit of electricity led to exploring wind power. The conducted wind resource assessment for the desalination facility, reveals that a single wind turbine rated at 2.4 <i>kW</i> at a hub height of 21.3 <i>m</i> is able to produce 4.0 <i>MWh</i> of electricity (approximately the 40% of the required electric energy). Four different system design scenarios were explored, three consider using existing equipment and one using new equipment (design from scratch). The system design analysis reveals that adding a wind turbine increases the cost of the electricity. However, the system design analysis reveals that adding a backup generator decreases the cost of the electricity. Finally, this thesis describes that the energy system design from scratch and able to supply electric energy at the lowest cost (0.35 $<i>/kWh</i>) is through a combination of PV (3 <i>kW</i>), CPV (5.2 <i>kW</i>), batteries (6 <i> kWh</i>), converter (4 <i>kW</i>), and a backup generator (3 <i> kW</i>).</p>

A finite element (FE) model is a computational representation of a given structure. In order for the FE model to accurately predict structure response, the model is "updated" or improved. This thesis investigates the use of artificial boundary conditions in sensitivity-based model updating and damage detection. A comparative analysis was conducted on the accuracy of error identification and location with respect to the artificial boundary conditions imposed and the number of modes retained. Results are demonstrated with actual test data from a simple structure.

Recent advances in technology have allowed for Small Unmanned Aerial Vehicles (SUAVs) to employ miniaturized smart payloads such as gimbaled cameras, deployable mechanisms, and network sensors. Gimbaled video camera systems, designed at NPS, use two servo actuators to command line of sight orientation via serial controller while tracking a target and is termed Visual Based Target Tracking (VBTT). Several Tactical Network Topology (TNT) experiments have shown high value of this new payload but also revealed inherent delays that exist between command and actuation of the pan-tilt servo actuators controlling the camera. Preliminary analysis shows that these delays are due to a communication lag between the ground control station and the onboard serial controller, a data processing delay within that controller, and the mechanical delays of the gimbal. This thesis applies system identification techniques to the servo controller system and considers the implementation of a Smith Predictor into the camera control algorithm in order to reduce the overall effect of the lag on the system performance.