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Data-Driven Methods for Identification, Control, and Resilience Enhancement of Modern Power Systems and Microgrids
No full textThe electric power systems worldwide are experiencing a rapid transformation as conventional synchronous generation is being replaced by power converter-interfaced resources that lack inherent inertia at both distribution and transmission levels. This shift has led to increased uncertainty and nonlinearity, resulting in challenges for accurate modeling and efficient control of generation resources needed to maintain secure, resilient, and efficient grid operations. Thanks to advancements in sensing infrastructure with the availability of sensors, transducers, phasor measurement units, and smart meters, a plethora of data has become accessible to engineers and operators for effective design, monitoring, and decision-making purposes. Therefore, this dissertation focuses on utilizing high-resolution data for data-driven modeling and control of power converter-based resources in bulk power system and microgrid applications. Both DC and AC power systems are explored to cover a wide range of applications. The first part of the dissertation, specifically chapters 2-4, concentrates on offline identification techniques for control design, linear and nonlinear dynamic model identification, and operational resilience assessment in DC microgrids. The second part of the dissertation, encompassing chapters 5-6, focuses on direct adaptive control of grid-forming inverters (GFMIs) in AC power systems based on online parameter estimation techniques to enhance resiliency against model uncertainties and malicious attacks. Chapter 2 employs a frequency scan method to design a complex droop control scheme, enabling dynamic power sharing among heterogeneous distributed energy resources (DERs) in DC microgrids, allowing for an accurate frequency-based response for DERs and improved damping. Chapter 3 develops two distinct frameworks based on a sparse regression algorithm for nonlinear and linear model identification of DC-DC converters. The first framework enables the identification of the open-loop nonlinear dynamic model of the converter under test (CUT), which can be used for control design. Due to challenges in deriving the closed-loop dynamic model of the CUT using the sparse regression algorithm, a second framework is proposed that facilitates transfer function identification for the closed-loop output impedance of the CUT, which can be utilized in small-signal stability monitoring. In Chapter 4, a data-driven operational resilience assessment framework is proposed for DC microgrids that utilizes the frequency scan method to identify the bus impedance transfer function of the DC microgrid and develops a frequency-domain operational resilience metric based on transfer function norms to quantify transient energy imbalances. In Chapter 5, we present the model-reference adaptive damping (MRAD) method, designed to modulate the dynamic response of GFMIs amid grid uncertainties. This controller leverages online frequency and active power data to adjust damping gains, ensuring a consistent dynamic response regardless of grid strength and disturbances. Finally, Chapter 6 discusses the resilient MRAD (RMRAD), which enhances MRAD by incorporating input disturbance estimation for robust performance against data integrity and destabilization attacks on GFMI control systems.</p
Investigating the Role of Degree of Unsaturation of Polyester Film Formers for Improved Fiberglass-Reinforced Composite Strength
No full text{"value":"Wind turbines are an increasingly important source of renewable energy, that rely on fiberglass reinforcement for their strength, stiffness, and durability. The effectiveness of fiberglass reinforcement hinges on the sizing used to coat and protect the glass strands. This sizing facilitates stress transfer from the matrix to the fiberglass, enabling wind turbines to withstand the high forces they encounter in the field over many years.Traditionally, sizing optimization has focused on silane coupling agents, with less emphasis on other components like the film former. Among the film formers studied, epoxy has received the most attention, while the unsaturated polyester film former has been less explored. Currently, there is limited research on optimizing the reactivity of unsaturated polyester film formers with their thermosetting polyester matrix resin.
This study aims to understand how the degree of unsaturation in an unsaturated polyester film former affects composite strength, ultimately leading to improved field performance. Here, the performance of three different unsaturated polyester film formers, each with varying degrees of unsaturation were evaluated. Included in this study along with the three reactive film formers were two systems which did not contain matrix reactive film formers but did contain matrix reactive silane coupling agents, these served as the control.
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A Quantitative Investigation of Electrode Capacitance Associated with Green Manufacturing of Silicon Carbide Nanowires for Use in Supercapacitors
No full textAs we advance towards a sustainable energy economy, the transition demands the development of greener, more environmentally responsible energy storage technologies. This study investigates the green manufacturing of silicon carbide nanowire (SCNW) electrode materials for supercapacitor applications utilizing anthracite coal, silicon powder, biopolymer binders, and an iron catalyst. SCNWs were produced via pyrolysis at 1400°C under inert atmosphere conditions, forming an interconnected network offering increased surface area characteristics observed by Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS). Electrochemical performance was characterized through cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) testing in a three-electrode system with 1M H₂SO₄ electrolyte, yielding a maximum specific capacitance of 3.23 F/g highlighting both the challenges and the opportunities in optimizing sustainable electrode materials. Despite modest initial performance relative to industry benchmarks, the findings establish a sustainable, low-cost, low-energy synthesis route for silicon carbide (SiC)-based electrode materials without reliance on hazardous chemical precursors or extreme processing conditions. This research uniquely demonstrates the potential of utilizing abundant natural resources in a scalable, low-impact process, contributing to the broader goal of commercial innovation in sustainable energy storage technologies.</p
Flexible Electrodes for Dysphagia: Needs Assessments Drive Bioengineering Innovation
No full textDysphagia is a neuromuscular impairment that disrupts the coordinated swallowing processes and thereby poses challenges for patients to transmit a solid or liquid bolus from the oral cavity to the stomach. The following can result in life-altering medical challenges for these individuals that severely increase their financial burden and diminish their quality of life. Designing a methodology that improves upon current methods of monitoring and improving swallowing function offers a sustainable approach to improving long-term care for these patients. Current clinical methods for monitoring and providing therapeutic outcomes for dysphagia require frequent clinical interventions and lack objective metrics in improving swallowing output. Neuromuscular electrical stimulation (NMES) promotes neuroplasticity, angiogenesis, and skeletal muscle hypertrophy and repair through tetanic muscle contraction. Despite the availability of neuromuscular electrical stimulation technologies that are currently commercially available, there remains several unmet clinical and technological gaps that call to be bridged. The fabrication of a next-generation wireless electroceutical platform that mitigates iatrogenic skin injuries, skin erythema, and non-specific cathodal vasodilation has been initiated. Incorporation of a wireless design for this electrode will benefit pediatric patients who often find wired designs obstructive and distracting. Ongoing engineering efforts have led to the development of a flexible electrode material designed for skin-friendly, low impedance surface stimulation and biofeedback data acquisition. Clinically, this work translates to a platform technology that can help provide improvements in neuromuscular activation and signal transmission of swallowing-based metrics as a holistic approach to improving patient care quality for patients with dysphagia. The following electrode material was fabricated using a poly-vinyl alcohol (PVA)/glycerol host elastomeric material intercalated with a carbon black nanocomposite. The electrode material demonstrated enhanced mechanical durability, as determined by uniaxial tensile and cyclic testing, ensuring long-term structural integrity under physiological conditions. Additionally, the electrode material exhibited low lateral and through-thickness impedance measurements within frequencies ranges that correspond with NMES and surface electromyography (sEMG). Furthermore, the electrode material’s biocompatibility, validated through ISO 10993-5 testing, confirmed its suitability for prolonged skin contact without irritation or adverse reactions. Simultaneously, a sEMG swallowing pilot study was conducted to assess the real-time swallowing biofeedback for fluids of different viscosities for the purpose of determining key swallowing features in healthy individuals. The data for this pilot study was analyzed with a signal processing algorithm that enhanced time-series signal quality by combining nonlinear median filtering for impulsive noise removal and wavelet-based denoising via discrete wavelet transform with soft thresholding. Linear interpolation was utilized for missing values, ensuring smooth transitions and effective noise suppression while preserving critical swallowing features. Continued EMG biofeedback is essential for identifying key differences in both healthy and non-healthy patient populations in future studies. These parallel studies were pitched to a diverse group of stakeholders and clinicians, as part of a customer discovery process during participation in the regional National Science Foundation’s Innovation Corps program. Collaborations allowed for interaction and input from speech language pathologists and other clinicians at Good Shepherd Rehabilitation. These ongoing collaborations support the crux of this work, which is a needs-driven assessment aimed towards developing a translational pathway to bioengineering benchtop work. </p
Regional Estimations of Water Quantity Necessary for Adequate Hand Hygiene in Low and Middle Income Countries
No full text{"value":"There is a fundamental lack of research and data that exists on the quantity of water necessary for actual and ideal handwashing practices in low- and middle-income countries (LMIC’s). We sought to identify data to estimate the quantity of water required for actual and ideal hand washing practices to support water, sanitation, and hygiene (WASH) interventions in LMIC’s. A comprehensive scoping review was conducted in April 2024 to gather relevant data to be used in analysis to create estimations of actual and ideal minimum water use for hand hygiene in WHO regions. A PICOS framework was defined with inclusion criteria: populations in community settings, households, schools, and food preparation in LMIC’s; intervention of handwashing with soap and water; no specific comparisons were defined; reported or predicted outcomes for handwashing water quantity, flow time and rate, and number of hand hygiene activities conducted; included study types of controlled field or laboratory trials, observational studies, and handwashing station design or manufacturer specifications.
Encompassing and relevant search terms were developed and searched inPubMed, MEDLINE Ultimate, and Web of Science databases. Searches in databases resulted in a total of 5,606 studies uploaded to Covidence, with 1,418 duplicates removed prior to title and abstract screening. Studies included in full text screening were based on their adherence to the inclusion criteria and PICOS framework. All stages of screening were completed in duplicate by two researchers and consensus was assessed by the supervisor. 331 papers were included in the final extraction stage. An extraction template was created to pull relevant data from each study, with completed extractions being downloaded as a .csv file. A tiered use system was implemented to give a range of estimates across different settings and use levels; 50 mL per hand wash, 250 mL per hand wash, and 500 mL per hand wash were indicated for low, medium and high use respectively.
A calculator was built that utilized the varying use-levels and handwashing frequencies to estimate volume of water per person per day in each WHO region using reported and observed data. The resulting estimates for the Africa Region (1.4 - 5.7 L/p/d) and South East Asia Region (1.4 - 5.1 L/p/d) fall into the ballpark of the 2 - 6 L/p/d for general hygiene reported in literature (Sphere Handbook Section 2.1) and 6 L/p/d for hand hygiene (Utami et al. 2023) in a peri-urban setting. Estimates for the Eastern Mediterranean Region, Western Pacific Region, and Region of the Americas were significantly less, indicating a need for more data from these regions and representation of water use for hygiene to accurately assess ideal minimum water needs. ","attr0":"abstract"
Nonpersons in Nikan: Violence & Vengeance in R.F. Kuang\u27s The Poppy War
No full textEmpire building and the consequences of colonization are pervasive in R.F. Kuang’s The Poppy War (2018); however, the complicated relationship between patriarchy and personhood in the novel is far more subtle and yet to be explored. As the novel’s protagonist Fang Runin (Rin) attempts to navigate Nikan’s political landscape, her superiors violently revoke her agency as they commandeer her shamanistic powers to commune with a powerful god as a means of furthering their military goals and defending the nation. This paper conveys how Kuang’s novel emphasizes the intimate relationship between patriarchal oppression and the characterization of people as nonpersons. Rin’s unique ability to commune with a god determines her irreplaceable value for the Nikan government while simultaneously “othering” her, which I argue establishes her status as a nonperson who is only necessary for as long as she is useful. Complicating Rin’s status as a nonperson is her willingness to obey the orders of her superiors as they recognize and praise her impressive abilities; however, this recognition is manipulative and accompanied by violence. Pulling from Imani Perry’s exploration of personhood in patriarchal structures can expose how those who fall outside of patriarchy’s normative standards are effectively oppressed and “othered,” inextricably linking violence to the creation of nonpersons. Through this link, I examine how the use of violence against Rin both in public and in private spaces informs the development of Rin’s character as a nonperson, as well as her increasingly violent resistance to oppression as the novel unfolds. This essay articulates that the patriarchal power utilized within Nikan can be wielded to destroy personhood and ultimately alter the future of the nation. It concludes by detailing the destructive consequences of cultivating a nation dependent on nonpersonhood.</p
Computational Studies in Drug Discovery and Drug Design
No full textMolecular modeling and simulations of biomolecular systems are crucial for understanding their behavior and play a key role in drug discovery and design, especially since protein-ligand affinity is a critical factor in developing new drugs. This dissertation primarily focuses on computational methods for predicting ligand binding affinity. Chapter 1 provides a brief introduction to widely used methods for ligand binding affinity calculations, highlighting their advantages and limitations. Chapters 2 presents the development and extension of the CHARMM-GUI module, Free Energy Calculator. Three submodules of the Free Energy Calculator were extended, enabling the generation of alchemical binding free energy (FE) systems for the AMBER package and providing scripting support for performing thermodynamic integration simulations with AMBER (AMBER-TI). Two benchmark systems (BACE1 and T4-lysozyme) were used to validate the generated systems and inputs, demonstrating good agreement with experimental data. In addition, based on our results, we recommend conducting at least 4 independent runs using the unified protocol and a 4-fs time step with hydrogen mass repartitioning (HMR) for efficient and reliable relative binding affinity (ΔΔG) calculations. In Chapter 2, we systematically tested 12 different force field (FF) combinations for running AMBER-TI to identify the optimal combinations, as FF selection is a critical factor in obtaining accurate results. Eight protein systems (BACE1, TYK2, CDK2, MCL1, JNK1, p38, thrombin, and PTP1B) were used to evaluate which FF combination would yield the best performance. Our large-scale ΔΔG calculation study provides good practices of FF selection for AMBER-TI ΔΔG prediction. While there is no statistically noticeable performance difference among 12 different FF combinations compared to the experimental values, the accuracy of the FF combination (ff14SB for protein, TIP3P for water, and GAFF2.2 for ligand) showed the best performance among the 12 FF combinations tested, based on mean unsigned error (MUE), root-mean-square error (RMSE), and Pearson’s (rP), Spearman’s (ρ), and Kendall’s (τ) correlations. This large-scale ΔΔG calculation study provides useful information about ΔΔG prediction with different AMBER FF combinations and presents valuable suggestions for FF selection in AMBER-TI ΔΔG calculations. In Chapter 4, we move beyond soluble proteins and focus on membrane-associated proteins for ΔΔG prediction. Four different G protein-coupled receptors (GPCRs) were used to predict ΔΔG using alchemical binding FE calculation methods: AMBER-TI and the alchemical transfer method (AToM) with OpenMM. Overall, both AMBER-TI and AToM-OpenMM show good agreement with the experimental data. Chapter 5 presents the development of the CHARMM-GUI Implicit Solvent Modeler (ISM), as using an implicit solvent model can significantly speed up simulations by drastically reducing the number of solvent degrees of freedom. Using the system and input files generated by ISM, implicit solvent simulations of protein, DNA, and RNA systems produced similar results across different simulation packages (AMBER, CHARMM, GENESIS, NAMD, OpenMM, and Tinker) with the same input information. Protein-ligand binding FE was also estimated from implicit solvent simulations using molecular mechanics/generalized Born surface area (MM/GBSA) for 88 protein-ligand systems. MM/GBSA is another attractive method to estimate ligand binding affinity, and our results show that it provides more accurate estimations compared to docking results. We expect that ISM will be a valuable tool for various studies that require implicit solvation methods.</p
Characterization of the Boulder Front Fault and Uplift Rates in the Northern Basin and Range Province, Idaho
No full textThe Northern Basin and Range Province in central Idaho is host to a series of active normal faults including the range-bounding Boulder Front fault along the SW slope of the Boulder Mountains. Situated in the upper Wood River watershed, the SW-dipping Boulder Front fault cuts a series of Pinedale-age moraines and fluvial outwash terraces with clear evidence of surficial rupture. At least 7 distinct fault segments dip ~SW and span more than 20 kilometers from Galena Summit to the SE of Boulder Creek. Evidence of multiple ruptures of the entire segment during the Holocene is observed with inset deposits being less offset than older terraces. Rupture ages were calculated from diffusion modeling of the fault scarp as a single slip rupture event (~4.27-7.08kyr±0.68kyr) and a continuous slip event (~2.99-4.96kyr±0.41kyr) with additional constraints provided by six radiocarbon dates (~1.12-4.48kyr±0.06kyr) in the footwall of offset fluvial terrace deposits. A recent rupture (<~2.81kyr±0.06kyr) is evident on the Boulder Creek segment while neighboring drainages suggest that other segments of the Boulder Front fault may have ruptured within the last ~1,100 years. Calibration of a diffusion coefficient for glacial sediment near Boulder Creek was determined locally to be 2.09x10-3 m2/yr. Recurrence intervals of ~2.3kyr and earthquakes of M5.7-M6.6 are calculated for the Boulder Front fault based on rupture-length relationships, diffusional modeling, and radiometric dating techniques. Erosion rates calculated from 10Be analysis and corresponding uplift rates from fluvial inversion modeling for regional catchments reveal that catchments with fault scarps have 3.5-4 times higher uplift rates than catchments with no visible scarps. Physical extension of the fault system may exist to the south towards the tourist destinations of Ketchum and Sun Valley, Idaho, and poses a seismic hazard to infrastructure and local populations.</p
Class-Wide Intervention to Increase Social Engagement Between Autistic Students and their Peers
No full textIndividuals on the autism spectrum often require additional support in the area of social communication. Peer mediated interventions target these areas by incorporating peers into the intervention. To date, most studies have focused on selecting one or two peers as models or peer interventionists with only a few studies implementing a class-wide intervention. This study implemented a class-wide intervention combining instruction on autism spectrum disorder: Stay, Play, Talk, and a group reinforcement contingency to increase autism knowledge, peer attitudes toward a focus student on the autism spectrum, and social engagement between peers and a focus student on the autism spectrum. The participants were from three kindergarten classes, with focus students on the autism spectrum. Participants demonstrated significant increases in their autism knowledge from pre-test to post-test. There were not significant differences in attitudes towards the focus student from pre-intervention to post-intervention measures. Finally, no changes were observed in social engagement following the introduction of the intervention. </p
Evaluation of Interface Shear Performance between Ultra-High-Performance Concrete and Conventional Concrete
No full textUltra-high-performance concrete (UHPC) is increasingly utilized as precast members along with cast-in-place conventional concrete (CC) to form composite members. The interface performance is crucial for ensuring the composite action in these structures. Therefore, this research assesses the interface behavior between the UHPC substrate and cast-in-place CC.Push-off tests were conducted on eleven specimens to investigate interface performance of fluted interface between UHPC substrate and cast-in-place conventional concrete (CC). Eight specimens featured fluted interfaces with varying flute geometries and interface reinforcement locations, while three specimens with smooth surfaces or flutes only served as reference lines. The study evaluated the effects of the ratio between the interface reinforcement and flute base area, as well as the distance between the interface reinforcement and flute edge. Additionally, the failure progression of the fluted interface was discussed.
The theoretical capacities predicted by AASHTO LRFD Guide Specifications for Structural Design with UHPC (AASHTO UHPC Guide) and AASHTO Guide Specifications for Design and Construction of Segmental Concrete Bridges (Segmental Guide) were evaluated. The results indicated that the AASHTO UHPC Guide is overly conservative, whereas the Segmental Guide is unconservative. A new predictive formula was developed based on the Segmental Guide, incorporating concrete material properties and flute geometries, which aligned well with the experimental results.
A new UHPC box section was developed for a short-span bridge, modified from the PA standard box beam. The design follows the AASHTO LRFD Bridge Design Specification (AASHTO LRFD), Pennsylvania Design Manual Part 4 (PA DM-4) and AASHTO UHPC Guide. The UHPC box beam is shallower than the minimum depth specified for PA standard box beam, allowing for increased clearance beneath the bridge. Three potential interface types were designed to illustrate the different demands for interface reinforcement.
Two experimental composite UHPC box beams were modified from the prototype beam to reduce the interface shear capacity. Two full-scale composite beams were fabricated and tested at each end to evaluate the interface performance. The force-deflection and force-end slip curves were analyzed, the composite action was assessed, the performance of each interface type was evaluated and the proposed predictive formula was validated through the full-scale beam tests.
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