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A SEISMOLOGICAL INVESTIGATION OF GROUND DEFORMATION FROM METEOTSUNAMI AND SEICHE ACTIVITY ON LAKE MICHIGAN
No full textThe mechanisms behind the formation and propagation of meteotsunamis and seiches—anomalous water waves generated by meteorological events that share similar spatial, temporal, and behavioral characteristics with seismically-generated tsunamis—are poorly understood. Small-scale ground tilt (microradians-nanoradians) triggered by these anomalous water waves in Lake Michigan is investigated with an array of 10 near-shore (\u3c 100 km) seismometers installed from 2012-2014 by calculating tilt from seismic recordings and comparing it with data from relatively nearby (10s of km) NOAA water level stations in Holland and Ludington, Michigan. After determining an appropriate period band from 15 minutes to four days to isolate these events, we show that potential meteotsunami and seiche activity on eastern Lake Michigan can be deduced from long-term trends (multiple weeks) in tilt and water level time series. Exploratory in nature, the methods and observations presented in this paper serve as an initial step in quantifying the potential for nearshore seismometers to monitor shoreline inundation. Integrating these observations with meteorological data could provide insights into the origins of these hazards by linking them to the specific weather events that generated them. This approach offers a novel method for improving the understanding and potential future mitigation of meteotsunami and seiche impacts in the Great Lakes region
PATIENT HANDLING INTERVENTIONS AND THEIR ROLE IN REDUCING MUSCULOSKELETAL DISORDERS AMONG HEALTHCARE WORKERS
No full textMusculoskeletal disorders (MSDs) are prominent among healthcare professionals, especially those who perform manual patient handling tasks. Assistive devices (e.g., slider sheet, gait belt, mechanical lift) have been used for patient handling. However, the effectiveness of these devices in reducing MSD risk factors is varied. Additionally, the relationship between healthcare workers’ acceptability of patient handling devices and organizational policies that facilitate or hinder widespread implementation is not well understood. The goal of my dissertation was to conduct a comprehensive analysis of existing patient handling devices and their role in mitigating MSD risk among healthcare workers. For Study 1, I conducted a scoping review to assess the literature documenting the biomechanical (kinematics, kinetics, muscle activity), physiological (oxygen consumption, heart rate), and subjective (perceived exertion) responses to common patient handling devices and emerging technologies (e.g., exoskeletons). Results indicated that patient handling risks and injuries can be reduced through a variety of assistive devices, evidence-based practices, and safety measures. In Study 2, I evaluated the effectiveness of three passive patient handling devices (gait belt, slider sheet, exoskeleton) in reducing factors associated with MSDs compared to manual lifting in healthcare workers (n = 10) Specifically, biomechanical, physiological, and subjective responses were assessed during two patient handling tasks: 1) turning a patient and 2) sit-to-stand transfer. Data indicated that compared to manual handling, use of assistive devices generally decreased erector spinae muscle activity and perceived exertion and thus potentially reducing MSD risk. For Study 3, I assessed healthcare workers’ (n = 10) acceptability of various patient handling devices through Systems Usability Surveys and semi-structured interviews. I also identified barriers to implementing these devices through a critical assessment of health and safety plans of rural hospitals in Michigan’s Upper Peninsula (n = 5). The key finding was that successful implementation is dependent upon both strong organizational support and acceptability of devices by the workers using the devices. Collectively, my research provides a comprehensive analysis of patient handling devices and their roles in MSD development among healthcare workers, as well as provides insight into the relationship between healthcare worker acceptability, device usability, and device implementation in healthcare settings
HOLISTIC ENERGY EFFICIENCY ANALYSIS OF ELECTRIFIED OFF-HIGHWAY MATERIAL HANDLER: FROM DRIVE CYCLE CHARACTERIZATION TO POWERTRAIN, HYDRAULIC, AND THERMAL SYSTEM PERFORMANCE
No full textThree complexities surrounding the operation and testing of hybrid electric, heavy-duty nonroad machines have been addressed experimentally and using 1D simulation. Their resolutions have been intertwined with the development of a prototype machine that was proven to reduce fuel consumption in excess of 20%. A real-world drive cycle that leveraged hydraulic cylinder position was developed and utilized to ensure accurate reproduction of hydraulic work between the baseline and hybrid machines, while simultaneously maintaining less than 5% RMS error in position for main load handling functions. The newly developed, machine-specific drive cycle also contributed towards making equivalent comparisons in energy consumption between machine types through composite performance metrics that were extrapolated over a typical shift duration. Lastly, this work addressed thermal management energy consumption, a topic of increasing popularity when discussing electrified vehicles, by proposing a 1.4% energy savings through special mechanization and control of cooling system components
Direct Methane Capture via Aerobic Methanotrophs
No full textMethane, a greenhouse gas with global warming potential 80 times greater than carbon dioxide, heavily contributes to global warming. Removing 1 Gt of atmospheric methane by 2050 would limit global temperature increase from reaching 1.5°C. Currently, biotrickling filter systems for removing atmospheric methane via methanotrophs exist, but not for very low methane concentrations (\u3c 1 v%). Current research work at the University of Washington isolated and engineered a microbe strain which thrives at 500 ppmv methane, solving one obstacle in making this technology feasible. In this thesis, techno-economic analysis and environmental life cycle assessment conducted on this process have assessed its economic feasibility, greenhouse gas reduction potential, and possible areas of improvement. Study results show that at 500 ppmv methane, this process could remove atmospheric methane at a cost of $3,992-5,224 per tCH4. The ideal case also produces annual net reduction in warming potential by 276-311 tCO2e per process unit deployed
Wood-water relationship and micro-chemical properties of huminated archaeological European elm (Ulmus laevis P.)
No full textArchaeological wood requires effective conservation to prevent further degradation, and traditional modifications such as polyethylene glycol (PEG) have limitations, including hygroscopicity and chemical degradation over time. To explore alternative modification, this study was conducted to investigate the suitability of humins, crosslinked with different concentrations of succinic acid (SA), to protect archaeological elm wood from the Agapia Monastery against water and to determine the modification mechanism. Key parameters such as dimensional stability, moisture sorption isotherms, and determination of accessible hydroxy groups as a function of humination modification were analyzed using dynamic vapor sorption (DVS). The modification mechanism was studied by microstructural and chemical properties evaluation by Confocal-Raman spectroscopy and scanning electron microscopy (SEM). Results indicated that humins, particularly crosslinked with SA, significantly improved the water-related properties of wood and its dimensional stability. The humination also reduced the accessibility of the hydroxy group, thus decreasing the equilibrium moisture content (EMC) of huminated elm at relative humidities (RHs) ranging from 0 to 95%. While SEM images revealed structural changes in the modified wood, Confocal-Raman spectroscopy confirmed the successful allocation of humins into the cell walls. This study demonstrates that humins are promising materials for archaeological wood conservation, providing improvements in both chemical and physical properties
Biopsychosocial profiles following ACL reconstruction: A latent class analysis of barriers to return-to-activity
No full textObjective: Understanding of how biopsychosocial factors interrelate to affect recovery from ACL injuries is essential for improving patient outcomes. This research aimed to use Latent Class Analysis (LCA) to classify individuals post-ACL reconstruction into subgroups reflecting their particular biopsychosocial challenges to recovery. Design: Cross-Sectional. Methods: This multisite investigation included 134 ACLR patients approximately 6 months (5.6 months ± 1.8 SD) following surgery. The ACL Reasons scale, various Patient Reported Outcome (PRO), and performance-based measures were assessed. LCA was used to categorize patients into subgroups based on the ACL Reasons scale. Subgroups were then compared across demographic, PRO, and performance-based measures using one-way analysis of variance and chi-squared tests. Results: LCA identified two distinct groups of patients who were less active after ACL reconstruction, characterized by varying levels of injury related fear, anxiety and depression. These groups reported lower outcomes and demonstrated reduced performance on hop tests in comparison to those who were as active as before their surgery. Conclusion: Patients less active post-surgery fall into two categories: one hindered by injury-related fear and symptoms, the other by mostly symptoms alone. Tailored interventions could enhance recovery, with one group possibly benefiting from psychological support and the other from a focus on functional and symptomatic treatment
Legends and Maps: Efforts to Reveal Hidden Curricula Knowledge Within Our Institution and Its Computing Courses
No full textHigher education institutions and the courses within them often expect that students will be able to seek out and find the resources that they need. The concept of \u27\u27hidden curriculum\u27\u27 has come to refer to that which is not taught, but that students are expected to know. This includes not only classroom content that instructors may expect students are already familiar with, but also methods for finding and navigating resources across the institution. Our team sought to help students within our institution with key \u27\u27hidden curricula\u27\u27 topics across their computing courses. In this experience report, we primarily examine our creation and deployment of a resource hub for computing students. We additionally report on how this project has provided insight to some efforts being conducted at an institutional level. By considering \u27\u27digital access\u27\u27 to certain resources through the lens of \u27\u27unspoken knowledge\u27\u27, new forms of \u27\u27hidden curricula\u27\u27 seem ready to be revealed
Refining Participatory Design for AAC Users
No full textAugmentative and alternative communication (AAC) is a field of research and practice that works with people who have a communication disability. One form AAC can take is a high-tech tool, such as a software-based communication system. Like all user interfaces, these systems must be designed and it is critical to include AAC users in the design process for their systems. A participatory design approach can include AAC users in the design process, but modifications may be necessary to make these methods more accessible. We present a two-part design process we are investigating for improving the participatory design for high-tech AAC systems. We discuss our plans to refine the accessibility of this process based on participant feedback
Performance Analysis of Multivariable Control Structures Applied to a Neutral Point Clamped Converter in PV Systems
No full textThis paper addresses the challenges encountered by grid-connected photovoltaic (PV) systems, including the stochastic behavior of the system, harmonic distortion, and variations in grid impedance. To this end, an in-depth technical and pedagogical analysis of three linear multivariable current control strategies is performed: proportional-integral (PI), proportional-resonant (PR), and deadbeat (DB). The study contributes to theoretical formulations, detailed system modeling, and controller tuning procedures, promoting a comprehensive understanding of their structures and performance. The strategies are investigated and compared in both the rotating ((Formula presented.)) and stationary ((Formula presented.)) reference frames, offering a broad perspective on system behavior under various operating conditions. Additionally, an in-depth analysis of the PR controller is presented, highlighting its potential to regulate both positive- and negative-sequence components. This enables the development of more effective and robust tuning methodologies for steady-state and dynamic scenarios. The evaluation is conducted under three main conditions: steady-state operation, transient response to input power variations, and robustness analysis in the presence of grid parameter changes. The study examines the impact of each controller on the total harmonic distortion (THD) of the injected current, as well as on system stability margins and dynamic performance. Practical aspects that are often overlooked are also addressed, such as the modeling of the inverter and photovoltaic generator, the implementation of space vector pulse-width modulation (SVPWM), and the influence of the output LC filter capacitor. The control structures under analysis are validated through numerical simulations performed in MatLab® software (R2021b) using dedicated computational routines, enabling the identification of strategies that enhance performance and ensure compliance of grid-connected photovoltaic systems