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Mount Storm Syndrome
No full textFirst timber, then coal, now rare earths — a century-long cycle of prospect and plunder has cast Mount Storm, West Virginia as a sacrifice zone in the hinterlands of the Mid-Atlantic. Anticipating the growing venture of rare earth recovery from acid mine drainage, Mount Storm Syndrome challenges the singular role of the extractive landscape as one of material production, instead exploring how the symptoms of previous industry can be retooled to test speculative futures. The Mount Storm Field Laboratory carries this mission: proposing a series of field experiments that tap into the physical byproducts of past extractions — leveled hills, drainage ditch networks, and contaminated aquifers — to place emerging practices of rare earth recovery in dialogue with former timber and coal operations. In doing so, the thesis provides a model for working in rural, extractive landscapes that embraces the novel perversities of their physical and ecological condition as a cultural asset to communicate a deeper history of disturbance. Within the broader discipline, Mount Storm Syndrome pulls from topics of disturbed sites, toxic discourse, and industrial heritage.Department of Landscape Architectur
Resolving Crystallographic Disorder in Heterobimetallic Clusters via Resonant X-ray Diffraction
No full textProbing the chemical makeup of polynuclear reaction centers is central to understanding how composition imparts functionality. Important chemical machinery (e.g., biological inorganic cofactors, catalysts, energy storage materials) often possesses multi-metallic structural elements essential to driving their function. Introducing different metals to the overall composition enables substitutional disorder within the solid-state structure, convoluting the study of structure-function relationships. Resonant X-ray diffraction leverages the large changes to an atomic scattering factor that occur at spectroscopic absorption edges (K-, L-, or M-edge) to differentiate between two different elements, allowing for the resolution of crystallographic disorder stemming from the mixed occupancy of an atomic position within the crystalline lattice. The stepwise synthesis of heterobimetallic trinuclear clusters on the hexaanilide ligand platform, FtbsLH6 (1,3,5-C6H9(NC6H3-4-F-2-NSiMe2tBu)3), generates samples featuring crystallographic disorder that results in mixed-metal occupancies at each site within the trinuclear cores. The compositional homogeneity of these heterobimetallic clusters enables us to test the limitations of metal occupancy refinement via resonant X-ray diffraction.
In Chapter 1, we introduce the theory and experimental protocols of a single-crystal resonant X-ray diffraction experiment. The classical derivation of the atomic scattering factor is provided along with key insights from quantum mechanics. Following this explanation, we review the information that single-crystal resonant X-ray diffraction experiments provide in the context of inorganic chemistry. Finally, the experimental design and data treatment procedures required to extract resonant scattering perturbations, f'(ω) and f''(ω), from single-crystal X-ray diffraction data are described.
In Chapter 2, we examine the accuracy of determining metal site occupancies in a [Fe2Zn] cluster using resonant X-ray diffraction by directly comparing the result to that obtained from single-crystal neutron diffraction. These studies showcased that resonant X-ray experiments were as accurate at determining metal site occupancies in the heterobimetallic clusters as neutron diffraction. We additionally explored the intrinsic error of single-crystal resonant X-ray diffraction studies when theoretical and experimental f'(ω) references are employed, showcasing that the use of homometallic molecular control samples carries an inherent uncertainty of +/- 5%.
In Chapter 3, we expand the synthesis of heterobimetallic clusters on the FtbsLH6 ligand platform towards [Zn2Ni] clusters. Reduction of the heterobimetallic (FtbsL)Zn2Ni(py) (3.3) cluster and subsequent reaction with the nitrene transfer reagent, N3Ad, generates the bridging μ3-nitrenoid adduct [K(THF)3][(FtbsL)Zn2Ni(μ3-NAd)] (3.5). This cluster can be further reduced by one electron, resulting in an isostructural dianionic cluster. The electronic configurations of these clusters were studied by SQUID magnetometry, EPR spectroscopy, and variable wavelength Ni K-edge XRF. These studies suggest a divalent oxidation state for the Ni centers in both the monoanionic and dianionic [Zn2Ni] nitrenoid complexes.
In Chapter 4, we examine which factors (i.e., resolution, scaling methods, uncertainty propagation, structural modeling) impact the ability to refine resonant scattering perturbations from synchrotron-based diffraction data collected at energies along the Ni and Zn K-edges utilizing the [Zn2Ni] clusters described in Chapter 3. Although the resonant effect is maximized at an element’s absolute absorption edge, perturbations to X-ray scattering are still present when the incident radiation is off-resonance. We found that the closeness of Cu Kα radiation (8042 eV) to the K-edge absorption energy of Ni and Zn is sufficient to accurately refine resonant scattering perturbations. Remarkably, the resonant scattering terms refined from in-house generated Cu Kα X-ray diffraction data replicated occupancies determined via synchrotron-based resonant diffraction.
In Chapter 5, the synthesis and structural characterization of several [Zn2Cr] clusters are explored. Reaction of FtbsLZn2Cr(py) (5.1) with aryl and alkyl azides generates bridging μ3-nitrenoid clusters. Depending on the nitrenoid substituent, these clusters display C1- or C3-molecular symmetry, enabling substitutional disorder within the trimetallic cores. As such, we turned towards two different methods to examine the solid-state Zn and Cr core occupancies: (1) structural refinement via ShelXL using EADP and SUMP constraints, and (2) refinement of the disordered sites’ resonant scattering perturbations when irradiated with Cu Kα radiation. Despite the energetic distance between the Cr K-edge (5990 eV) and Cu Kα X-ray radiation, the refined f'(Cu Kα) values for each core site yielded accurate occupancy estimates when compared against standard structural refinement.
In Chapter 6, the electronic and structural characterization of [Fe2M] (where M = Co or Ni) clusters is explored via elastic and inelastic X-ray scattering. The resonant scattering perturbations of these clusters were refined from Cu Kα and variable wavelength synchrotron X-ray diffraction datasets and used to calculate metal-site occupancies. Additionally, experimental resonant scattering factors were derived from the [Fe3], [Co3], and [Ni3], homometallic analogs to provide reference f'(ω) and f''(ω) values for Fe, Co, and Ni in the occupancy calculations. In addition to the structural characterization conducted via elastic X-ray scattering experiments, we were also interested in obtaining information on the electronic configuration of the [Fe2Co] and [Fe2Ni] cores via inelastic spectroscopy. Variable wavelength XRF and 57Fe Mössbauer studies revealed that the nature of the electronic charge distribution within the trinuclear core is dependent on the identity of the metals residing within.Chemistry and Chemical Biolog
Thermalization and criticality on an analogue-digital quantum simulator
No full textUnderstanding how interacting particles approach thermal equilibrium is a major challenge of quantum simulators1,2. Unlocking the full potential of such systems towards this goal requires flexible initial state preparation, precise time evolution and extensive probes for final state characterization. Here we present a quantum simulator comprising 69 superconducting qubits that supports both universal quantum gates and high-fidelity analogue evolution, with performance beyond the reach of classical simulation in cross-entropy benchmarking experiments. This hybrid platform features more versatile measurement capabilities compared with analogue-only simulators, which we leverage here to reveal a coarsening-induced breakdown of Kibble–Zurek scaling predictions3 in the XY model, as well as signatures of the classical Kosterlitz–Thouless phase transition4. Moreover, the digital gates enable precise energy control, allowing us to study the effects of the eigenstate thermalization hypothesis5–7 in targeted parts of the eigenspectrum. We also demonstrate digital preparation of pairwise-entangled dimer states, and image the transport of energy and vorticity during subsequent thermalization in analogue evolution. These results establish the efficacy of superconducting analogue–digital quantum processors for preparing states across many-body spectra and unveiling their thermalization dynamics.Proo
Cross-Market Signals: Economic Spillovers Across Markets
No full textThis thesis explores the growing interconnectedness of global markets, with a focus on the explanatory power U.S. and China macroeconomic factors have on each other's stock market returns. Using the JKP Global Factors Dataset with 13 themes and 153 factors, we model this relationship using linear regressions, sparse additive models, and kernel regressions. The analyses were conducted using the Wilshire 5000 and Shanghai Composite returns.
Across all models, U.S. economic data consistently improved the predictions of Chinese market returns, but Chinese economic data rarely added improved the predictions of U.S. market returns. Linear regressions revealed decent R^2 values using domestic data, with 0.70 R^2 0.80 for the U.S. market and 0.55 R^2 0.60 for the Chinese market. Sparse additive models and kernel regressions achieved higher R^2 values in the data. They were more likely to overfit to the data, with the partial dependence plots sometimes not following economic intuition. Future directions include accounting for interaction effects, attempting rolling-window methods, and exploring sector-level analyses to obtain more granular insights into market spillovers.Computer Scienc
Assessing Corporate Growth and Bankruptcy Risk Using Public Data Proxies
No full textThis thesis applies natural language processing (NLP) to job listing data as a novel predictive and explanatory tool for evaluating bankruptcy risk and corporate growth. Unlike models based on traditional financial ratios, which are limited by the sparsity of data for small and private companies, job postings provide abundant, real-time information relevant for nearly all corporations and enhance published corporate evaluation methods.
In this report, we demonstrate that the textual context within job listing data offers a meaningful signal for both predictive and descriptive purposes. Our analysis is applied to a corpus of approximately 51.8 million job listings generated from 6764 unique corporations over the roughly decade-long period from 2010 to 2020.
For bankruptcy prediction, our research presents models with robust predictive performances (accuracy 0.8652; specificity 0.8653; sensitivity 0.8042; ROC-AUC 0.9162) that mirrors or exceeds the predictive capabilities of reference baseline models from literature. We then discuss the potential of topic models as both a predictive and descriptive tool for the overall economy as a whole; though our work indicates limited performance of the topics as a predictive feature. Instead, their descriptive potential lies with the ability to track desired employment and thematic distribution across fields such as remote work-- concentrated in tech and management--or entry-level positions--concentrated in retail or delivery. Finally, we also present models evaluating corporate growth, where our predictions reflect the theoretical economic behaviors of debt-based and cyclical investment in the corporate bond and commodity-driven sectors.Computer Scienc
In Situ Techniques for Quinone-Mediated Electrochemical Carbon Capture and Release in Aqueous Environments
No full textWe present two novel experimental techniques designed to quantify the contributions of nucleophilicity-swing and pH-swing mechanisms to carbon capture in the electrochemical aqueous quinone-based CO2 capture process. Through thermodynamic analysis, we elucidate the intricate interplay between these two mechanisms, and emphasize the critical role of understanding this interplay in the material discovery cycle for carbon capture applications. This insight prompts the development of two innovative in situ techniques. The first technique capitalizes on discernible voltage signature differences between quinone, and quinone-CO2 adducts. By incorporating a reference electrode into the carbon capture cell setup, we apply this method to investigate bis[3-(trimethylammonio)propyl]-anthraquinones (BTMAPAQs). Our findings reveal the isolated contributions of nucleophilicity-swing and pH-swing mechanisms to overall carbon capture capacity under varying wait times and CO2 partial pressures. The second method is developed based on our finding that the adduct form of the quinone exhibits a fluorescence emission from an incident light at wavelengths distinct from the fluorescence of the reduced form, enabling differentiation through optical band-pass filtering at each unique fluorescent signature. Thus, we introduce a non-invasive, in situ approach using fluorescence microscopy, providing the unique capability to distinguish between oxidized, reduced, and adduct species with sub-second time resolution at single digit micrometer resolution. This powerful technique holds significant promise for studying such systems, representing an advancement in our ability to understand carbon capture processes.Chemistry and Chemical BiologyEngineering and Applied SciencesAccepted Manuscrip
Nano-scale Noise Spectroscopy for Materials Applications
No full textThe rise of two-dimensional (2D) materials has opened new frontiers for exploring low-dimensional physics. These systems exhibit distinct electronic and spin behaviors compared to their 3D counterparts, and offer tunability through stacking, twisting, and thicknesses control. Yet, their micrometer-scale lateral size and atomic-scale thickness pose a major challenge for conventional condensed matter probes, calling for highly sensitive, local measurement techniques.
In parallel, quantum information science has also made exciting technological advancements in the past decades. Quantum sensing, built on the precise control of coherent quantum systems, has become a powerful tool in precision metrology, biosensing, and condensed matter physics. Among various platforms, nitrogen-vacancy (NV) centers in diamond, originally developed for quantum networks, have emerged as a highly sensitive, non-invasive nanoscale probe for studying spin and charge dynamics.
NV centers have already proven their value through pioneering studies of magnetic and electronic properties in quantum materials, often cross-validated by optical spectroscopy and electronic transport. These early efforts paved the foundation for using NV magnetometry as a standalone probe to uncover new physics. With a mature understanding of device fabrication, spin–sample coupling, and coherent control techniques, NV-based sensing now accesses previously unreachable regimes of spatial, spectral, and temporal resolution in condensed matter systems.
This thesis is driven by the question: What makes NV centers uniquely powerful as magnetometers for condensed matter research? Specifically, how do their quantum coherence and sensitivity in momentum and frequency space enable access to new physical phenomena?
The thesis presents work that spans both validation and discovery. First, we used NV AC magnetometry to measure the magnetic penetration depth in the 2D cuprate superconductor BSCCO, obtaining values and temperature scaling consistent with established results. This part is discussed in Chapter 5. More significantly, we uncovered a new regime of spin transport in atomically thin Heisenberg ferromagnets: magnon hydrodynamic transport. Through the coherent spin response of NV centers, we directly observed magnon second sound—an analog of collective density wave in fluid. This work also expands the experimental toolkit for studying fluctuation–dissipation phenomena in low-dimensional magnets with spin decoherence properties.
This thesis begins with an overview of quantum sensing with NV centers and recent advances in understanding 2D magnetic materials. I then introduce NV noise spectroscopy—the central technique enabling the discovery of magnon hydrodynamics. Chapters 3 and 4 present experimental observations and theoretical insights into magnon hydrodynamic transport. Finally, Chapter 5 summarizes our independent BSCCO measurements and ongoing efforts toward wide-field NV methodologies, providing a complete record of our contributions to this emerging field.Engineering and Applied Sciences - Applied Physic
Water Hammer Phenomenon in Coronary Arteries: Scientific Basis for Diagnostic and Predictive Modeling with Acoustic Action Mapping
No full textBackground: In the study of coronary artery disease, the mechanisms underlying atherosclerosis initiation and progression or regression remain incompletely understood. Our research conceptualized the cardiovascular system as an integrated network of pumps and pipes, advocating for a paradigm shift from static imaging of coronary stenosis to dynamic assessments of coronary flow. Further review of fluid mechanics highlighted the water hammer phenomenon as a compelling analog for processes in coronary arteries. Methods: In this review, the analytical methodology employed a comprehensive, multifaceted approach that incorporated a review of fluid mechanics principles, in vitro acoustic experimentation, frame-by-frame visual angiographic assessments of in vivo coronary flow, and an artificial intelligence (AI) protocol designed to analyze the water hammer phenomenon within an acoustic framework. In the analysis of coronary flow, the angiograms were selected from patients with unstable angina if they had previously undergone one or more coronary angiograms, allowing for a longitudinal comparison of dynamic flow and phenomena. Results: The acoustic investigations pinpointed pockets of contrast concentrations, which might correspond to compression and rarefaction zones. Compression antinodes were correlated to severe stenosis, due to rapid shifts from low-pressure diastolic flow to high-pressure systolic surges, resulting in intimal injury. Rarefaction antinodes were correlated with milder lesions, due to de-escalating transitions from high systolic pressure to lower diastolic pressure. The areas of nodes remained without lesions. Based on the locations of antinodes and nodes, a coronary acoustic action map was constructed, enabling the identification of existing lesions, forecasting the progression of current lesions, and predicting the development of future lesions. Conclusions: The results suggested that intimal injury was likely induced by acoustic retrograde pressure waves from the water hammer phenomenon and developed new lesions at specifically exact locations.Version of Recor
Intraoperative Feedback System to Predict Long-Term Pedicle Screw Fixation using Modal Analysis
No full textThis thesis presents a novel intraoperative feedback system designed to predict long-term pedicle screw fixation in spinal fusion surgeries by leveraging modal (vibrational) analysis. Spinal fusion is a prevalent procedure aimed at stabilizing vertebrae in cases of degenerative disease, trauma, or deformity; however, current intraoperative methods for assessing pedicle screw stability largely rely on subjective tactile feedback. To address this gap, we developed a compact, single-handed device that excites the screw–bone construct with a controlled vibrational input and measures the response via an embedded sensor. Through fast Fourier transforms and resonance frequency detection, the system quantitatively gauges screw anchorage quality in real time.
Finite element analysis (FEA) of pedicle screws in bone analogs demonstrated that resonance frequency shifts reflect changes in bone–screw interface stiffness. Bench-top experiments with polyurethane foam blocks of varying densities confirmed strong correlations between resonant frequency and mechanical pull-out strength, validating the approach in a controlled environment. Further testing on cadaveric vertebrae reinforced the device’s clinical relevance, showing it can differentiate securely anchored screws from those at higher risk of loosening.
Designed for seamless integration into the surgical workflow, the tool displays a simple color-coded readout (green/yellow/red) to guide intraoperative decision-making. User feedback from orthopedic surgeons highlights the system’s potential to reduce revision rates and hardware failures by enabling immediate identification of suboptimal fixation. Future work will focus on extending compatibility to polyaxial screws, refining signal processing algorithms for greater robustness, and undertaking large-scale clinical studies to establish the device as a standard instrument for spinal fusion procedures.Engineering Sciences A
Plasma treatment to remove titanium surface contaminants and improve implant biocompatibility: an in vitro study
No full textPlasma technology is an emerging treatment with potential for implant surface decontamination and surface modification. Our in vitro study evaluates the effects of plasma treatment on fibroblast and osteoblast adhesion, proliferation, and differentiation on titanium surfaces. Plasma treatment was applied to machined and rough-surface titanium discs, and surface characterization was conducted using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and hydrophilicity tests. Cell adhesion and proliferation were assessed through SEM imaging, viable cell assays, and immunohistologic staining. Statistical comparisons between control (no plasma) and test (plasma) groups were performed using an independent two-sample t-test (α = 0.05). While SEM imaging showed no significant changes, XPS analysis revealed a substantial reduction (p .001) in carbon content, indicating decreased hydrocarbon buildup. Plasma treatment significantly increased surface hydrophilicity in both machined (p 0.0001) and rough (p 0.0001) surfaces, suggesting potential benefits for implant osseointegration. SEM and IHC imaging of fibroblast and osteoblasts showed a higher prevalence of cells in the test group. Cell viability assays indicated significantly greater live cell attachment in plasma-treated groups for both osteoblasts and fibroblasts at early time points, though the differences were not observed after 12 hours. In conclusion, plasma treatment of titanium surfaces, 1) reduce hydrocarbon buildup, 2) enhances surface hydrophilicity, and 3) improve early-stage fibroblast and osteoblast attachment to titanium surfaces. Further research is needed to explore whether these findings are clinically significant through clinical trials, and whether the technology can be used in the treatment of peri-implant disease.Periodontolog