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Developing Guidance for the Use of Floating Treatment Wetlands in Brackish Stormwater Ponds
Get PDFStormwater ponds are commonly used as a flood control strategy, particularly in coastal developments. Many coastal stormwater ponds are impaired with high nutrient levels that can lead to algal blooms, impacting the water quality of the pond and surrounding ecosystem. Floating treatment wetlands (FTWs) are one potential strategy that can be implemented in stormwater ponds to reduce high nutrient concentrations, however limited research has been done in brackish waterbodies. To determine the suitability of using FTWs in brackish stormwater ponds this research focused on (1) coastal resident perceptions of FTWs and (2) plants that can be utilized in FTWs deployed in brackish ponds. Focus groups and online surveys with coastal residents were performed to determine their priorities when deciding to support FTW installation in their community. Next 11 aquatic macrophytes were screened in a greenhouse over a range of salinities to determine their growth and nutrient uptake capabilities under salinity stress. Finally, full-scale FTWs were deployed in 3 brackish ponds in Mt. Pleasant, SC to determine FTW success in water quality improvement. Results indicate the secondary benefits of FTWs like aesthetics and habitat creation are important to residents and should be incorporated in FTW design to gain community support. Plant selection will need to be guided based on the salinity of the pond as not all plants can survive mesohaline conditions
Organizational Metamorphosis: When Artificial Intelligence Transforms Companies into New Economic Life Forms
Get PDFTraditional theories of organizational change fall short in explaining how artificial intelligence (AI) transforms organizations. This grounded theory study, based on interviews with 34 organizational leaders, identifies a novel phenomenon: organizational metamorphosis - the irreversible transformation of organizations into fundamentally new entities through deep integration with AI as a cognitive partner.
The metamorphosis process unfolds in three phases. Individual Awakening occurs when leaders experience powerful interactions with AI, prompting a rapid shift from skepticism to advocacy. Once a critical mass of leaders undergo this shift, it initiates Organizational Restructuring, characterized by reimagined work design, boundary dissolution, and altered temporal rhythms. These changes create the conditions for Emergent Evolution, in which organizations develop human-AI symbiosis and new capabilities that surpass the capacities of either party alone.
The study introduces the concept of synthetic dynamic capabilities - capabilities that are instantly scalable, perfectly replicable, and continuously evolvable without traditional resource constraints. This challenges core assumptions in strategic management regarding resource scarcity and competitive advantage. The research also identifies AI-intensified paradoxes that organizations must embrace to sustain ongoing transformation.
By theorizing organizational metamorphosis, this study offers new insights into human-AI hybrid entities, reconceptualizes sources of competitive advantage, and provides practical guidance for leaders navigating deep AI integration
Accurate Temporal Integration Schemes for Nonlinear Adsorption Problems
Get PDFWe consider a nonlinear transport problem to model the chromatography process of high-capacity multimodal membranes. Robust and efficient algorithms that simulate these bioseparation processes are critical to developing therapeutics for various chronic illnesses and infectious diseases. However, much of the current methodology focuses on stabilization and linearization techniques, often implementing low-order time-discretizations and linearized adsorption, resulting in inefficiencies and inaccuracies in the numerical solution. Utilizing Rothe\u27s method, we develop various time-discretization schemes coupled with the finite element method to solve the fully implicit problems. Stability and solvability results are presented for several methods. Through multiple high-level software implementations paired with national laboratory solvers, we verify a priori error estimates and generate breakthrough curves to test the experimental validity of the numerical solutions. We also test our methods by sweeping over the feasible set of adsorption parameters. Our results indicate that these methods have significantly improved the current simulation framework to model downstream filtration processes
Gesture-Based Icon Messages: Examining the Effects of a Nonverbal Transparency Strategy for Supporting Situation Awareness in Human-Autonomy Communication
Get PDFAutomated systems continue to transform tasks that were once manual, introducing new challenges for operators to maintain situation awareness (SA). This research examines gesture-based icon messages (GIMs) as a transparency strategy to address challenges present in human-autonomy communication (HAC). Drawing from Endsley’s (1995) three-level model of SA, GIMs were designed to convey different types of information: perception, comprehension, and projection. The goal of this work was to understand whether GIMs could be distinguished by operators, and whether they support SA under conditions that reflect the divided attention demands that are common in operational settings. Study 1 focused on assessing whether participants could differentiate between GIMs based on the intended SA level, while Study 2 and Study 3 tested how GIMs influence SA and performance in a low fidelity driving task. Findings from Study 1 showed that participants were able to distinguish between GIMs designed for perception, comprehension, and projection, supporting the idea that these messages can target specific information categories. In Study 2 and Study 3, comprehension level GIMs provided higher SA benefits under multitasking conditions than projection level GIMs, suggesting that message complexity may play a role in operator performance. Text-based messages outperformed GIMs at the projection level, which highlights the importance of considering message format and information type in transparency design. Overall, this research contributes to our understanding of how nonverbal communication strategies can be applied to support SA in HAC, and underscores the need to tailor message design to the demands of the operational context
12CO Ro-Vibrational Spectroscopy of Protoplanetary Disks: Inferring Planet-Disk Interactions
Get PDFObserving and studying planets around young stars during their initial formation stages is essential for understanding the physics of their formation. Protoplanetary disks are the host sites of planets, and they exhibit substructures that hint towards the planets\u27 presence, but the planet itself has rarely been detected. Analysis of the substructures in protoplanetary disks, especially towards the inner regions where most planets seem to lie, will provide information that can be used to refine theories about planet-disk interactions and, ultimately, planet formation. To probe the high-velocity inner regions, this study utilizes high-resolution spectroscopy, which has increased sensitivity with increasing velocities. This study focuses on the protoplanetary disks surrounding two young stars, CI Tau and AB Aurigae, that display substructures and host independently verified companions. As such, connecting the disk substructures to the planets inhabiting the disks of these systems is vital for the ongoing search for planets.The disk around CI Tau has an undepleted inner region, determined from the infrared excess in its spectral energy distribution and it also hosts an eccentric massive companion, deduced from a radial-velocity survey. As such, observations of this disk can provide first-of-its-kind results of how planets can influence their natal disks. Theories exist describing such a planet-disk relationship, but it is unclear how accurate they are as very few planets have been detected while still deeply embedded in a disk. For example, due to the planet\u27s influence, the region of the disk near the planet\u27s immediate vicinity is expected to develop an eccentricity comparable to that of the planet\u27s orbit. My analysis of CI Tau revealed that its inner disk, where the planet resides, has an eccentricity of 0.05, which was much smaller than the eccentricity attributed to the proposed planet at the time. As such, we concluded that the planet\u27s eccentricity must be smaller. Another feature captured in CI Tau\u27s inner disk was that the companion bisects it. Without forming a deep or detectable gap, the component of the disk that is interior to the planet\u27s orbit is oppositely oriented to the exterior component. The location where the bisection occurs was 0.14~au, which is smaller than the planet\u27s orbit size --- hinting that it may also be in a different location. The multi-component disk I observed from CI Tau was the first time such a feature was captured, and it can serve as the foundation of planet-disk interaction theory moving forward. AB Aurigae\u27s disk has been imaged numerous times and a multitude of substructures have been identified, such as rings/gaps, vortices, spirals, etc. The most famous substructure is the protoplanet candidate AB Aur b, a bright, concentrated emission source on a wide orbit. By targeting this star, we can understand the relationship between the luminosity of a forming planet with respect to that of the background disk. Observations were done for multiple position angles to capture varying emissions from the protoplanet. Doing this can allow us to place limits on the forming planet\u27s luminosity --- an unknown quantity. Spectroscopic emission of CO directly from AB Aur b was not captured even though it has been a consistently imaged feature in multiple wavelengths. This non-detection of AB Aur b in the CO infrared emissions either indicates it is a rather cold feature or lacks a concentration of CO; both conclusions are essential to incorporate in planet formation models. Also, the non-detection can directly inform the theorized formation mechanisms based on their implied \u27hot-start\u27 or \u27cold-start\u27 scenarios.Since this study targeted systems that have been independently verified to host protoplanets, our observations were expected to reinforce those discoveries. Instead, for both systems, our analysis hints at the presence of different planets. For example, instead of modifying the orbital parameters of CI Tau\u27s previously known companion, our results suggest a new 1~M planet on a low 0.05 eccentricity orbit around 0.14~au. For AB Aurigae, instead of detecting AB Aur b, our results point to a different planet located about 65~au southwest of the star, which are distinctly different coordinates from AB Aur b\u27s. Even though our detections are not definitive, our analysis techniques can be used in the future as an additional tool for verifying protoplanet discoveries.Our high-resolution spectroscopic analysis of CI Tau and AB Auriage serves as foundational calibrations for theories relating to planet-disk interactions and planet formation. Said theories have been developing for decades but have had minimal observational backing as very few planets have been detected while forming in a protoplanetary disk. Our results here provide some of the first data points that can be incorporated into theoretical models to help refine them. When refined, these models can better capture the physics around young planetary systems and, ultimately, help answer the question of \u27How do planets form?\u2
Data-driven Koopman Theory for Transient Stability and Safety Analysis of Power Systems with Renewable Penetration
Get PDFThis dissertation presents a novel approach to analyzing and controlling nonlinear systems using the Koopman operator framework and data-driven methods. Nonlinear power systems, characterized by complex behaviors and sensitivity to initial conditions, pose significant challenges for stability and safety assessment, especially during transient events.
The first part of this work focuses on reachability analysis using the spectral properties of the Koopman operator. By leveraging eigenfunctions extracted from sampled trajectory data, the approach computes forward and backward reachable sets efficiently, even in high-dimensional nonlinear systems, without requiring dense state-space sampling. This method is validated through numerical examples, demonstrating its ability to recover nonconvex reachable sets in both stable and unstable regimes.
Building on this, the dissertation develops a Koopman spectrum-based method for identifying stability boundaries in nonlinear systems. This method, applied to power system models, enables accurate computation of critical clearing times and transient stability analysis by constructing unstable eigenfunctions through a path integral formulation.
Finally, the dissertation addresses voltage safety under renewable generation uncertainty. A data-driven Koopman-based model is constructed using Extended Dynamic Mode Decomposition (EDMD), and a control barrier function is synthesized to enforce voltage safety. The resulting formulation is posed as a constrained optimization program, through which the minimum rated power capacity is computed to ensure safe operation across all disturbance scenarios.
The proposed methodologies provide scalable, data-driven tools for stability analysis and safe control in nonlinear systems, with practical applications in power system analysis and control
Understanding the Elements of Sterile Processing Workflow: OR, Sterilization and Personnel
No full textThe Sterile Processing Department (SPD), also known as the Central Sterile Services Department (CSSD), is an essential part of hospitals and healthcare facilities and is responsible for ensuring the cleanliness, sterility, and proper functioning of medical instruments. Sterile processing departments (SPDs) are key drivers of productivity, effectiveness, safety, and infection control in hospitals. A well-designed SPD workflow can enhance patient safety, reduce operating room (OR) delays, and improve productivity. To understand the flow of sterile processing and interactions between the OR and SPD, process maps and task analyses were developed through direct observations of the basic SPD functions: decontamination, assembly, sterilization, storage, and case cart preparation. In this research, we focus on the following functional units and personnel behavior factors: (1) Surgeon / OR behavior, (2) SPD behavior, and (3) Administration behavior. Each functional unit can be the source of challenges, such as (1) duplicate tray requests, replacement tray needs, on-time start pressures, (2) flash sterilization, fast tracking trays, staff shortages, and (3) wages, training, and turnover, respectively. Using the instrument tray as the basis for assessing flow through the SPD and the OR, we explore the behavioral decisions originating from the three functional units mentioned. Historical data, statistical analysis, and simulation modeling are employed to assist administrators in analyzing the impact of the following on sterile processing: surgical volume and schedules, tray and instrument requirements, staffing, equipment capacities, and cart-washing requirements. In some instances, OR personnel request additional trays beyond what is needed to make sure they have every instrument they might possibly need. This results in putting undue strain on the SPD’s inventory of trays and its ability to process dirty trays and instruments. This risk-averse approach to instrument and tray requests can lead to front-line staff considering workarounds to sterilization or other procedures in order to deliver instruments to the ORs on time. For this reason, we identify the likelihood of surgical delays and the required tray turnaround times at various levels of surgical volumes and additional tray requests. This study demonstrates how simulation modeling can be effectively leveraged to inform employee retention strategies and structured onboarding programs, as well as using data-driven methods to guide resource allocation and tray inventory decisions
Emotional Safety in Pediatrics: The Impact of Child Life Services on Healthcare Professionals’ Perceptions of Their Own, Patients’, and Families’ Outpatient Experiences
Get PDFMedical visits, regardless of setting, are stressful for children and their families. Care that focuses on the emotional safety of children and families can help reduce this stress. However, not all staff feel prepared to provide emotionally safe care. Child life specialists (CLSs) are specifically trained to support emotional needs during healthcare encounters. Their presence may help staff stress as well, not just stress for children and families.
This study used three surveys to understand stress among healthcare staff working in pediatric outpatient clinics and surgery settings, and how support from a CLS affects staff, children, and families. All staff reported work-related stress. CLS reported the highest levels of stress, possibly due to their consistent involvement in emotional care. Other staff felt less stressed and more satisfied when a CLS was present, and many reported that CLS support improved the overall experience for both patients and staff.
These findings suggest that CLSs may help reduce staff burnout and help healthcare staff feel more supported. This, in turn, supports better care for children and families
Flipping the Script?: The Development and Validation of a Qualitative Framework for Identifying Key Cognitive and Attitudinal Components of Conflict-Based Problem Representations
Get PDFWhen people work together, disagreements are inevitable. How someone understands a given conflict, specifically whether they see it as a shared problem or not, can shape how they respond and whether they look to resolve it collaboratively. Researchers have studied many aspects of conflict, like what causes it and the strategies people use to manage it. But we know much less about how people think about conflict in the first place and how those thoughts affect efforts to manage conflict. This research developed a tool to study how people describe conflicts in writing. It identifies key ideas and attitudes that suggest whether someone is likely to approach a disagreement in a collaborative way. The tool was created in a few steps. First, experienced conflict mediators were consulted to come up with a list of things people might say that would indicate how collaboratively they’re thinking about the problem. Second, professionals who might use the tool for scientific or training purposes provided feedback about how useful and usable they thought the tool was. Lastly, researchers tested the tool to see if it could identify a difference in how people that had received conflict management training described conflict vs. those who had not
Experimental Evaluation and Comparison of Football-Related Head Impacts Among Ovine, Human, and Hybrid III Headforms
No full textConcussions and traumatic brain injury (TBI) remains a significant public health concern, especially in American football, where repeated head impacts pose long-term risks to athlete health. While current helmet testing standards rely heavily on the Hybrid III surrogate headform to evaluate protective performance, these surrogate models lack anatomical accuracy and exclude the presence of a brain component, limiting their ability to capture the true mechanics of concussion. To address this limitation, this research developed and validated a novel inverted impact testing method that allows the impact testing of a Hybrid III headform and a cadaveric specimen. Additionally, this fixture preserves natural head-neck articulation and enables realistic evaluation of ovine and cadaveric specimens. Using wireless accelerometer arrays placed in both the skull and brain, this study quantified skull and brain kinematics across multiple impact scenarios.
The experimental methodology was applied to both bare head and helmeted conditions, and comparisons were made to Hybrid III headform impacts under equivalent conditions. The results demonstrated consistent differences in angular velocity linear acceleration and rotational acceleration between the sensors within the skull and the sensors within the brain, highlighting the insufficiency of skull-only measurements in concussion research. Helmeted conditions reduced kinematic magnitudes overall, but skull-brain discrepancies persisted. Additionally, ovine models were used to further evaluate the fidelity and repeatability of the inverted impact method