Institutional Repository

The UDSpace Institutional Repository collects and disseminates research material from the University of Delaware.

Faculty, staff, and graduate students who want their research material hosted in UDSpace should contact the University of Delaware Insitutional Repository team at openaccess@udel.edu.
Faculty may use UDSpace to fulfill the University of Delaware Faculty Senate Open Access Resolution, and in many cases may use it to fulfill open access requirements from grant funding agencies.
Departments can use UDSpace to publish or distribute their working papers, technical reports, or other research material.
UDSpace also includes all doctoral dissertations from winter 2014 forward, and all master's theses from fall 2009 forward.

To learn more about UDSpace, and how you can make your research openly accessible to the public, visit our UDSpace Information website.

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Recent Submissions

Disorder-enhanced spin Hall effect in Ru-Pt alloy thin films
(Physical Review Applied, 2026-07-10) Bheemarasetty, Vineetha S.; Wang, Xinhao; Shrestha, Shreya; Jungfleisch, Benjamin; Gundlach, Lars; Xiao, John Q.; Xiao, Gang
The search for material systems exhibiting a large spin Hall effect is central to the development of ultrafast, energy-efficient spintronic technologies. We systematically investigate the spin Hall angle (SHA) in Ru-Pt binary alloys using three complementary techniques: spin-torque magneto-optic Kerr effect, spin-torque ferromagnetic resonance, and time-domain terahertz emission spectroscopy. Within the measured composition range, a maximum SHA of 0.158 is observed in Ru38⁢Pt62, representing a 56% enhancement over Pt while maintaining a resistivity below 70 μΩ cm. Notably, these high SHA values are achieved in as-grown sputtered films across the full composition range without the need for complex fabrication procedures or high-temperature annealing. These results establish Ru-Pt as a scalable model alloy system in which composition-driven disorder, together with gradual structural evolution, governs spin-charge conversion, providing a practical pathway for optimizing materials for spin-orbit torque devices.
Overview of the limb injury measurement battery for quality of life (LIMB-QOL)
(Quality of Life Research, 2026-07-04) Tulsky, David S; Tyner, Callie E; Boulton, Aaron J; Kisala, Pamela A; Slotkin, Jerry; Dearth, Christopher L; Childers, W. Lee; Zafonte, Ross; Kalpakjian, Claire; Kingsbury, Trevor; Choi, Seung W; Sherer, Mark; Bartlett, Susan; Tintle, Scott
Purpose The Limb Injury Measurement Battery for Quality of Life (LIMB-QOL) was developed to comprehensively assess patient reported outcomes (PRO) for research and clinical use with individuals who have sustained major extremity trauma and limb loss. Methods A mixed-methods approach was used that included qualitative focus groups with civilians, service members, and clinicians as well as quantitative PRO data collection with individuals with a history of major traumatic limb injury or limb-loss due to such trauma or sudden-onset illness. Individuals with dysvascular and other chronic disease causes were excluded. Qualitative data were collected via focus groups (n = 56 individuals with major extremity trauma; n = 34 clinicians) and cognitive debriefing interviews (n = 41 individuals with major extremity trauma). Quantitative data were obtained through structured phone interviews with a large sample representing the target limb trauma and limb loss population (n = 603). Newly developed item banks were calibrated using graded response model item response theory analysis. Results LIMB-QOL includes 25 measurement scales including 10 new, targeted item banks developed with and for individuals with major limb trauma and 15 existing PRO item banks measuring salient physical, emotional, and social aspects of health-related QOL. Computer adaptive tests and short forms were programmed into the Assessment Center application programming interface and are now available through REDCap and other platforms. Conclusion LIMB-QOL provides a comprehensive and standardized system of PRO assessments for individuals with amputation or limb preservation due to sudden-onset limb injury. Research and clinical applications are discussed.
A New Ordinal Framework for Real-Time Traffic Risk Assessment Using an Integrated Surrogate Safety Measure
(IEEE Access, 2026) Naseralavi, Saber; Soltanirad, Mohammad; Piri, Mehran; Ranjbar, Erfan; Baghersad, Mahdi; Lucero, Martin; Zada, Mohammad Javad Hassan; Mazaheri, Akram
Traffic conflict analysis has traditionally relied on binary classifications of surrogate safety measures (SSMs) to identify high-risk events. This approach overlooks the continuous and multifaceted nature of risk, failing to fully capture drivers' behavioral responses across varying levels of conflict severity. This paper introduces a two-stage framework to overcome these limitations. In the first stage, we develop a robust, continuous risk metric by creating an integrated index from an ensemble of seven safety indicators and 800 threshold combinations. By aggregating information from multiple safety perspectives, this integrated index provides a more robust estimate of risk. In the second stage, this continuous risk metric is transformed into a five-level ordinal variable representing risk intensity, ranging from Safe to Critical. A Partial Proportional Odds (PPO) ordered logit model is then developed to predict the probability of a vehicle being in any given risk level based on its dynamic state. Using high-resolution NGSIM data, our results demonstrate that vehicle dynamics are powerful predictors of risk intensity. Specifically, the model reveals that the effect of speed on risk escalation is stronger at lower risk levels. Furthermore, modeling drivers' evasive actions in high-risk conditions shows that the likelihood of hard braking significantly decreases as speed increases. This finding uncovers a behavioral gap at high speeds, highlighting the need for intelligent assistance systems. Out-of-sample validation confirmed the model's robustness, achieving an overall accuracy of 84.0% and a Weighted Kappa of 0.916. A computational benchmark demonstrated a mean processing time of 1.83 ms per scenario, supporting the computational feasibility of a real-time application.
Updated Predictions for Vera C. Rubin Observatory Ultracool Dwarf Parallaxes
(Research Notes of the AAS, 2026-07-15) Gizis, John E; Honaker, Easton J.; Yoachim, Peter; Jones, R. Lynne
We update the predictions for Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) measurements of ultracool dwarf parallaxes in light of changes in the recommended survey strategy and performance. Despite numerous changes, the predicted volume probed for the 2025 recommended strategy (OpSim V5.0) was within a few percent of the 2022 (OpSim V1.7) results over ten years. Increasing predicted survey downtime (OpSim V5.3) to more realistic values, however, results in volumes about 10% lower. We draw attention to how the rolling cadence strategy affects parallax performance in parts of the sky over the first two years. Overall, Rubin is predicted to significantly increase the numbers of L and T dwarfs with parallaxes over current samples, enabling studies of very-low-mass stars and brown dwarfs.
TESOL Teacher Educator Emotion on GenAI and Expertise Development
(TESOL Journal, 2026-07-05) Roose, Tamara Mae; Hwang, Ju-A
Rapid advancement of GenAI technologies has elicited strong emotional reactions, increasing the demand for educators to enhance their expertise regarding these innovations. This paper examines the dialogic development of two TESOL teacher educators' expertise by exploring their initial reactions to GenAI use in education through their individually written memos and reflective dialog, along with Zoom class transcripts, Zoom chat box conversations, and teacher candidates' weekly assignments. Findings suggest that the teacher educators' reactions were characterized by intrigue, uncertainty, insecurity, and duty tied to their different background knowledge, roles, and responsibilities. The dialogic relationship between their emotions and expertise development suggests that adaptive expertise is facilitated by reflection and social interaction, shaped by internal and external pressures.