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Enhancing Quadruped Robot Design With Intelligent Physics-Informed Neural Network-Assisted Dynamic State Estimation and Active Spine Integration
Get PDFThis dissertation represents my master's work on quadrupedal robot systems at the Autonomous System Laboratory, University of Nevada, Reno. It primarily focuses on the intelligent design of quadruped robots and unmanned vehicles. The intelligence in these designs stems from advanced state estimation techniques and the integration of an active spine, combining constraints from physical models with insights from learning-based studies. An advanced Robot State Estimation (RSE) methodology is introduced, which uses a combination of a Physics-Informed Neural Network (PINN) and an Unscented Kalman Filter (UKF) with proprioceptive sensory data to enhance state estimation accuracy. This approach effectively calibrates the Inertial Measurement Unit (IMU), mitigates IMU drift through constraints applied via Ordinary Differential Equations, and eliminates the need for external contact sensors by identifying terrain interactions, improving odometry, and operational reliability in real-world scenarios. Next, the focus is on enhancing the physical limitations of traditional robotics platforms. To achieve this, we utilize a dynamic spine to enhance flexibility and absorb impacts, which necessitates reevaluating the robot's dynamic model. To manage these complexities, the physical model estimation is enhanced, and Reservoir Computing is employed for real-time adaptive control. This significantly improves robotic mobility and stability in challenging environments
Development of Au-Pt Nanoflowers as Nanoenzyme for Highly Sensitive Immunoassay: Application to the Detection of Melioidosis Biomarker
No full textImmuno-sensing techniques, which are well-known for their high efficiency and selectivity, have become widely used for detecting biomarkers in clinical and research settings. Nanoparticles with enzyme-mimic properties, known as nanozymes, have garnered significant attention for their potential in revolutionizing immuno-sensing due to their tunable catalytic activity, well-developed synthesis techniques, and stability across a wide range of pH, temperature, and inhibitor concentration. Among these, Au-Pt nanostructures exhibit exceptional peroxidase-mimic catalytic activity, making them promising candidates for enhancing immunoassay techniques such as ELISA and LFIA. In this work, different nanoenzymes and their use in immunoassay application were reviewed. In this study, we present a core shell gold-platinum nanoflowers (Au-Pt NFs) as signal labels in immunoassays for sensitive detection of capsular polysaccharides (CPS) expressed on the cell envelopes of Burkholderia pseudomallei causing Melioidosis, an infectious disease of global health concern. Utilizing the inherent peroxidase-like activity of Au-Pt NFs, we developed Nano-Enzyme Linked Immunosorbent Assay (N-ELISA) and Lateral Flow Immunoassay (LFIA) techniques for on-site and sensitive CPS detection. Au-Pt NFs were synthesized by growing Pt nanoflowers on gold nanoparticles (AuNPs) surfaces, ensuring dual functionality as signal labels. Through the use of a developed nanoenzyme, lateral flow assays for CPS were made possible using the Au-Pt NFs conjugated with anti-CPS antibodies. By only using the Au-Pt NFs without sophisticated instruments, it was possible to visually detect the test and control lines. Through colorimetric enhancement, our Au-Pt NF-based LFIA demonstrated superior sensitivity, detecting CPS at a minimum concentration of ~70 pg/mL, surpassing previous AuNP-based LFIA methods. Clinical diagnostic utility was validated by successfully detecting CPS spiked in human serum samples (~100 pg/mL).The utilization of Au-Pt NFs as signal labels in immunoassays offers a promising avenue for enhancing diagnostic capabilities, particularly in infectious diseases like Melioidosis. By overcoming the limitations of conventional enzyme-based assays, Au-Pt NFs pave the way for rapid and accurate point-of-care diagnostics
State-selective imaging of single rubidium atoms in a solid neon matrix
No full textThe development of single-spin quantum sensors with nanoscale resolution would provide immense utility in the determination of molecular structure, with applications in fields such as biology and chemistry. This dissertation discusses our progress toward using rubidium atoms trapped in solid neon as single-atom quantum sensors. The process of doping rare-gas solids allows for the co-trapping of arbitrary atoms and molecules, which is an advantage for nanoscale sensing. The dopants can also be buried inside the bulk of the solid, which is useful for avoiding noise from the surface. We begin with an overview of relevant optical and magnetic properties of the trapped Rb atoms, measured using an ensemble of atoms, that are critical for quantum sensing of magnetic fields. These include the absorption and fluorescence spectra of the atoms, which have interesting and complicated structure, the resilience of the atoms to optical bleaching, and the proportion of the atoms that fluoresce when optically excited. We can also control the quantum states of the atomic ensemble through optical pumping, create coherent superpositions of these states via pulsed RF excitation, and determine the ensemble spin-dephasing time T2*, which is on the order of tens of microseconds. By using dynamical decoupling techniques, we obtain ultralong spin-coherence times T2 on the order of 0.1 s. We also show that the dynamical decoupling sequence turns the atoms into an effective AC magnetometer. We use the atoms to detect the nuclear magnetic resonance of nearby unpolarized 21Ne nuclei, demonstrating the potential for performing nanoscale sensing measurements. The dissertation concludes by detailing the progress we have made toward performing single-atom sensing measurements: we image single atoms trapped in the matrix, measure several key optical properties of the lone atoms, and demonstrate optical readout of the spin state of a single atom in a rare-gas matrix. This combination of spin-coherence properties and single-atom optical properties presented in this dissertation makes Rb atoms in Ne extremely promising for nanoscale quantum sensing
Achieving Near-Natural Locomotion in Transfemoral Amputees - A Control Theoretic Approach
Get PDFAmputation of the lower limb is prescribed to address conditions such as trauma, vascular issues, tumors, neuropathy, frostbite, and complications from diabetes. Post-surgery, the individual has to be fitted with a prosthetic limb to regain mobility. While a good-fitting, well-designed prosthetic device can help support body weight and locomotion, the loss of lower limb muscles profoundly impacts body support, and stability and often results in asymmetrical gait patterns. Traditionally, prosthetic limbs were designed primarily to support weight and mimic the appearance of natural limbs. However, modern prosthetic devices aim for active functionality, striving to replicate near-natural human locomotion. However, achieving such functionality is not an easy task as the control of the prosthetic limb has to determine the user's intent while adapting to unknown nonlinear dynamics, and varying terrain and environmental conditions. Among lower limb amputations, transtibial amputations are the most common. The loss of the ankle joint for transtibial amputees causes several constraints during gait, such as lower walking speed, increased metabolic energy expenditure, and reduced power in the amputated limb during the push-off phase. For above-knee amputations, where the individual loses both the knee and ankle joints, the effects are more severe. Losing multiple joints leads to significant asymmetry in gait, which can affect musculoskeletal health in the long run
Punk Identification With Middle-Class Values
Get PDFPunk has been studied as a social movement and as a form of youth subculture, in this paper, both sides of punk research will be bridged to see how punk draws in participants and instills new values into them. Punk changes the values of its participants through its recruitment of adolescents and introducing them to new values in DIY punk spaces. Data was collected from 15 punks in Reno, Nevada using semi-structured interviews. This research confirmed that there are two main values that punks generally believe, and they are: a sense of community created within the scene and the other value is that of anti-establishment ideals. Those values are then the basis of punks rejecting middle-class values that are prevalent throughout American society. Namely, the ideas that underpin the American meritocracy as allowing anyone to climb the social ladder if they participate in the system correctly. This was both seen in the answers given by the participants of this study and the political organizations they participated in. Several participants are part of mutual aid organizations that are organized in non-hierarchical manners adhering to punks' anti-establishment nature and that directly tackle perceived systemic issues in American society through community building. However, punk in Reno has a blind spot when it comes to race issues within the scene and understanding the issues faced by people of color attempting to enter the scene by white punks. There is still a vibrant punk scene that has a history of political actions and printing political zines and has allowed for the changing of the value sets of the people that participate within it
Determining Optical Basicity of Molten Chloride Salts for Solar Thermal Applications
Get PDFAs demand for sustainable energy sources increases in response to calls for lower carbon emissions, research and development to improve relevant materials is imperative. Concentrated solar power (CSP) and thermal energy storage (TES) are valuable technologies that, when coupled, allow for intermittent solar power to be stored as thermal energy in molten salt. Thermal storage allows for energy to be accessed when sunlight is not available. This improves wide-scale grid stability, which is a common issue with other renewable energy sources. Molten salt is commonly used in CSP/TES, as its high operating temperature, high energy density, and thermal conductivity contribute to high operating efficiencies. However, molten salts are highly corrosive in atmospheres containing water and oxygen that are present in the CSP/TES. The salt can corrode the storage materials, typically nickel-based alloys, causing ruptures and subsequent plant shutdowns. In aqueous systems, pH can be a predictor of corrosion, but the non-aqueous, harsh environment of molten chlorides makes pH measurements irrelevant. Alternative basicity metrics, such as optical basicity (OB), are needed to predict corrosion. OB allows for measurement of the Lewis basicity, or the extent of electron donation from ligands in the molten salt, via the nephelauxetic effect of an added probe ion. In this work the OB of several alkali and alkaline earth chloride salts was measured by doping them with d10s 2 probe ions, Pb2+ and Bi3+, and quantifying the probe ion's redshift relative to that observed in the reference salt (LiCl-KCl eutectic). The probe ion absorbance frequency was observed in-situ using UV-vis spectroscopy for salts melted in a custom furnace. This work found Pb2+ and Bi3+ to be valid probes for molten chloride salts, with alkali chlorides being the most basic, alkali/alkaline earth chlorides containing Ca2+ and Sr2+ being slightly less basic, and AlCl3-NaCl being the least basic. Increasing temperatures also reflected a higher basicity for LiCl-KCl and AlCl3-NaCl. While Bi3+ OB data was consistent with Pb2+ data, there was significant volatilization of the probe that made detection impractical. The addition of transition metals such as Fe (III) and Cr (II) introduced charge transfer spectra that overshadowed the probe ion absorption peaks in the UV region, making OB determination impossible. Finally, UV-vis absorption data was collected for molten Li-Na-KCO3 eutectic. This eutectic was observed to rapidly corrode silica, so sapphire was used as an alternative material. The carbonate eutectic was also observed to readily precipitate the Pb2+ probe ion as lead oxide, so the OB could not be determined by UV-vis in this case
Towards Resilient Models: A Deep Learning Odyssey through Mammographic Images
No full textRecent advancements in deep learning have revolutionized the landscape of breast cancer diagnosis and analysis. While these strides have been remarkable, challenges persist in developing robust and accurate models tailored specifically for medical imaging tasks. This thesis explores the complexities of this domain by addressing two pivotal aspects: mammographic image classification and segmentation. In contrast to conventional single-view analyses, this approach recognizes and harnesses the intrinsic correlations among the four views in a mammography exam. An innovative multi-view network based on transformers is introduced, specifically crafted to elevate mammographic image classification. The contribution includes a distinctive shifted window-based dynamic attention block, leveraging transformers to seamlessly integrate multi-view information. This facilitates efficient information transfer between views at the spatial feature map level, resulting in a substantial improvement in tumor detection. To further investigate the impact of Convolutional Neural Network (CNN) architectures for medical image segmentation, two novel CNN architectures, ConnectedUNets+ and ConnectedUNets++ are proposed, each tailored for single-view segmentation. Additionally, for multi-view segmentation, an enhanced Cross-View Attention Network block is introduced. Collectively, this thesis contributes to the refinement and advancement of deep learning models for breast cancer diagnosis and analysis, with a specific focus on multi-view classification and segmentation tasks. The proposed methodologies exhibit promising results and pave the way for future developments in the field of medical image analysis
Heritage Management Archaeology: Writing Stakeholders in the George Whittell Forest, Washoe County, Nevada
No full textThis thesis explores approaching archaeological research from a heritage management perspective to potentially broaden opportunities for stakeholder engagement. It discusses the history of Cultural Resource Management (CRM) in the U.S., and how the resultant legal and theoretical frameworks guide archaeological CRM practices. It considers the impact of these practices on heritage stakeholders, using this understanding to write a historic background context for the Whittell Forest, a University of Nevada, Reno property. This context synthesizes previous research from archaeologists, including museum collections from previous UNR Anthropology research, historical documents, and research from other heritage disciplines. The archaeological research that has taken place in and around the area is discussed as one set of stakeholder interests out of many in the Whittell's heritage. All of these are discussed as a thematic synthesis, before being explored through theoretical frameworks. It concludes with recommendations to Whittell management, and implications for similarly heritage-oriented research
Studying the Competence Regulon Quorum Sensing Circuity in Streptococcus mitis
No full textQuorum sensing (QS) is a bacterial mechanism for modulating gene expression in response to cell-population density via intercellular communication. QS bacteria generate and release chemical signal molecules known as autoinducers, which increase in concentration as cell density increases. To determine the cell density and initiate the group behaviors such as virulence factor production, biofilm formation, and competence development bacteria rely on the production and release of signaling molecules into their environment. QS could thus be utilized as a potential non-antibiotic therapeutic strategy to control infections without affecting the survival of the bacteria, thus minimizing the selective pressure for resistance development. Streptococcus mitis , a pathogenic bacterium, utilizes the comABCDE competence regulon QS circuity. However, the competence stimulating peptide (CSP), the signaling molecule, that is responsible for QS activation, is not identified yet. In this work, we set out to identify the CSP of S. mitis and study the molecular mechanisms underlying the interaction and binding of CSP and its analogs with the histidine kinase receptor, ComD. We isolated the CSP and confirmed its sequence by MS/MS analysis. Analyzing the structure-activity relationship of CSP's alanine screen analogs gave us insights of their binding and interaction with ComD receptor. Most of the analogs shows more activity than the native CSP