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School readiness profiles of Head Start children: stability and within-profile variation
No full textBruch, Sarah K.Kindergarten entry is a critical time for young children that helps to shape their academic, social-emotional, and cognitive developmental trajectories. Differences in the competency levels of school readiness contribute to starting-gate inequalities in education. These entry-level differences can be attributed to children’s sociodemographic backgrounds and prekindergarten experiences. Understanding children’s development of school readiness and the variation in their skill sets highlights the need for a nuanced understanding of school readiness development in marginalized populations. Previous person-centered school readiness studies find varying patterns of school readiness. Some studies observe stability and changes in these profiles within the same school year or across grades. This study contributes to this research as one of the first to include literacy and executive function skills as part of the school readiness profiles and to observe the stability of these profiles across two time points within a low-income population. Using the Head Start CARES (Classroom-based Approaches and Resources for Emotion and Social Skill promotion) restricted secondary data, the aim of this study is (1) to observe how school readiness skills (emotion knowledge, social problem-solving, social skills, interpersonal skills, executive functioning, behavior problems, learning behaviors, and preacademics) combine in unique ways within four-year-old Head Start children, and (2) to observe the stability of the school readiness profiles over the course of the prekindergarten school year. Using a latent class analysis model, this study identifies five distinct school readiness profiles with varying levels of school readiness functioning—overall high needs, average social skills/behavior problems/learning behaviors, mixed levels of functioning, strong emotion knowledge/executive function/preacademics, and overall strength. These profiles indicate variations in school readiness skill patterns for Head Start children. Using a latent transition model, this study finds five distinct school readiness profiles at the beginning and end of the prekindergarten school year, but with qualitative changes for the average profile and the strong profile in the spring. Ultimately, most children were more likely to move to a different qualitative profile (65 percent) throughout the prekindergarten school year, with the exceptions of the strength profile (78 percent) and the high needs profile (55 percent), where children were more likely to stay. The findings from this project will contribute to the knowledge of across- and within-group school readiness skill set differences. This will allow early identification of those who need more support, a more targeted approach to teaching, and to inform curricular, instructional decisions, and intervention to better align with children’s unique skill sets and contributing demographic and background factors.University of Delaware, School of Public Policy and AdministrationPh.D
Defining forming limits of highly aligned discontinious fiber composites
No full textThostenson, Eric T.Cender, Thomas A.Advani, Suresh G.Carbon fiber reinforced composites have become a material of interest in various high-performance sectors such as aerospace and automotive applications due to their high stiffness to strength ratio, allowing for improved durability and energy saving. Typically, carbon fiber reinforced composites are made with continuous carbon fiber which imposes limitations on manufacturability due to inextensibility of the fibers. Highly aligned discontinuous fiber (ADF) composites have been shown to achieve aerospace-grade properties and have the additional advantage to stretch form biaxially to complex geometries. This thesis focuses on evaluating the formability of ADF composites utilizing Tailored Universal Feedstock for Forming (TuFF) aligned fibers combined with thermoplastic and thermoset resin systems. The primary aim is to establish a comprehensive process-structure-property relationships for ADF composites through novel methodologies for defining forming limits and characterizing material performance. ☐ A novel aligned discontinuous fiber forming limit diagram (ADF-FLD) was developed to define formability for this class of material relative to material orientation. Methodologies were developed to construct a forming limit diagram (FLD) for ADF composites, providing a detailed framework for strain mode forming limits based on lamina fiber orientation and a predicted thickness variability in a closed mold and an open mold forming process. To demonstrate this, ADF composite blanks were stretch formed to various strain levels and modes (longitudinal plane strain, transverse plane strain, and biaxial plane strain), while employing both in situ and ex situ techniques to measure deformation. By manipulating surface ply orientations of ADF laminates (0, 45, or 90 degrees) relative to the major strain direction, different strain modes were imposed and measured using photogrammetry post forming and digital image correlation (DIC) for real time strain analysis. ☐ First, a method was developed to characterize deformation of multiaxial thermoplastic TuFF laminates in a series of closed molds at various strain levels, using a double diaphragm gas bulge forming process and photogrammetry to analyze strains post forming. A first-order failure definition based on a predicted thickness coefficient of variation relative to average strain was employed to evaluate the forming limits of the material and populate an ADF-FLD, describing the formability of the ADF composite. ☐ Additionally, a method was devised to characterize the deformation response of multiaxial thermoset TuFF laminates in diaphragm forming for longitudinal and transverse plane strain. Using a gas bulge method and an Interlaken SP75 highly instrumented forming press, high fidelity strain measurements were obtained via an in situ 3D digital image correlation system. This method allowed for real-time recording of surface strains, allowing for progression of strain variability to be measured continuously. The same failure criterion was applied to the strain data, and an ADFFLD was constructed with repeatable results for each strain mode. ☐ Overall, this thesis provides a comprehensive methodology and experimental framework for defining forming limits and optimizing the stretch forming process of ADF composites. The outcomes offer significant insights into the material and process variables, crucial for the design and manufacturing of complex composite parts in aerospace and other high-performance applications.University of Delaware, Department of Materials Science and EngineeringM.M.S.E
Non-local game homomorphisms
No full textTodorov, Ivan G.In the past few decades, the connections between non-local games arising in quantum information theory and the theory of operator algebras have undergone a phase of significant development. Operator algebras provide a particularly fruitful framework for approaching questions of non-locality in quantum systems, as the input-output behavior of measurements on bipartite quantum systems can be encoded through noncommutative operator algebras and their state spaces. This thesis is the compilation of a series of papers, written by the author in collaboration with Ivan G. Todorov, utilizing this framework by using the theory of operator algebras and completely positive maps to study questions involving non-local games. ☐ Using the simulation paradigm from information theory, we define a quantized version of homomorphisms and isomorphisms between classical hypergraphs, generalizing quantum homomorphisms and isomorphisms of graphs from the literature. We show that these quantum homomorphisms and isomorphisms constitute pre-orders and equivalence relations, respectively. We use quantum homomorphisms of hypergraphs to provide multiple examples of strict separation between correlation classes of varying types. Specializing to the case when our underlying hypergraphs arise from classical non-local games, we define quantum non-local game homomorphisms and isomorphisms. We also show how the existence of a homomorphism or isomorphism of some fixed type between games is reflected in a comparison of optimal and asymptotic game values with respect to this type. These non-local game homomorphisms are defined via a new class of non-signalling correlations which we introduce here. We develop the multivariate tensor product theory in the category of operator systems, which we then use to provide a characterization of game homomorphisms in terms of state spaces for various tensor products of canonically associated operator systems. We then apply these results to the study of synchronous non-local games, defining jointly synchronous correlations and showing how they correspond to tracial states of tensor products of C*-algebras canonically associated to each game party. ☐ We then move to a second level of quantization by proposing a "quantized" notion of hypergraphs (where "quantum" here is in the sense of a non-commutative analogue for a discrete combinatorial object), and introduce quantum homomorphisms between these quantum objects. We provide an initial foray into the properties quantum morphisms between quantum hypergraphs display, showing they satisfy analogous properties to quantum homomorphisms between classical hypergraphs. We also indicate initial connections these quantum homomorphisms between quantum hypergraphs have to the study of quantum input-output games. We end the thesis showing that homomorphisms of a local type between quantum hypergraphs is closely related, and in some cases identical, to the TRO equivalence of finite-dimensionally acting operator spaces canonically associated with each hypergraph. This suggests a quantum information theoretic approach to Morita equivalence in the category of operator spaces.University of Delaware, Department of Mathematical SciencesPh.D
Reversible temperature-induced shape transition of Pt nanoparticles supported on Al2O3
No full textThis article was originally published in Nanoscale Advances. The version of record is available at: DOI https://doi.org/10.1039/D5NA00930H
© 2025 The Author(s). Published by the Royal Society of Chemistry
Open Access Article. Published on 07 November 2025. This article is licensed under a Creative Commons Attribution-Non Commercial 3.0 Unported Licence.Supported platinum catalysts are widely used in industry for hydrogenation reactions. The variations of the electronic and geometric properties of Pt nanoparticles due to temperature can greatly affect their reactivity. In this work, we use in situ X-ray absorption spectroscopy and environmental transmission electron microscopy to study the effect of H2 and temperature on the shape and electronic properties of 1.8 nm average diameter Pt nanoparticles supported on Al2O3. We utilize actively trained machine learning potentials with uniform acceptance force-bias Monte Carlo (fbMC) to estimate the structural distribution of Pt15/g-Al2O3 (110) clusters at finite temperatures. Our predicted cluster geometries are consistent with experimental data showing the nanoparticles reversibly change shape from 3D hemispheres at low temperatures (35–100 °C) to 2–2.5D rafts at higher temperatures (200–400 °C). Furthermore, experiments and computations indicate that the contraction in Pt–Pt bond distances and higher electron density on Pt at higher temperatures are attributed primarily to the change in nanoparticle shape and associated increased interaction with Al2O3. Our results show the fluxional nature of supported Pt nanoparticles driven by temperature changes.This research was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Catalysis Science program, under award DE-SC0022144. This research was supported in part through the use of Information Technologies
(IT) resources at the University of Delaware, specically the high-performance computing resources. The microscopy work was supported by the Cooperative Research Program of Institute for Catalysis, Hokkaido University (20A1004 and 22DS0123). Use of the Stanford Synchrotron Radiation Light Source (SSRL, beamline 9–3, user proposal 4645), SLAC National Accelerator Laboratory is supported by the U.S. Department of Energy, office of Basic Energy Sciences under Contract No. DEAC02- 76SF00515. Additional support by the Consortium for Operando and Advanced Catalyst Characterization via Electronic Spectroscopy and Structure (Co-ACCESS) at SLAC is acknowledged. Co-ACCESS, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences and Biosciences under Contract DE-AC02-76SF00515. Finally, we thank Dr Fernando Vila for insightful discussions and feedback
Probing Voltage- and Electrolyte-Dependent Monolayer Dynamics with 2D-IR Spectroscopy
No full textThis article was originally published in Journal of the American Chemical Society. The version of record is available at: DOI https://doi.org/10.1021/jacs.5c14718
© 2025 The Authors. Published by American Chemical Society
This article is under embargo until October 24, 2026
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This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials.Little is known about structural dynamics at electrode surfaces under applied potential. Here, we report 2D-IR spectra of a 4-mercaptobenzonitrile monolayer on a gold electrode, revealing chemical exchange between two subensembles on sub- to tens-of-picoseconds time scales. Dynamics are measured in 100 mM MgCl2, LiCl, and KCl at −200 and +300 mV vs Ag/AgCl. At +300 mV, all electrolytes exhibited ≥48 ps exchange, while at −200 mV, the slower exchange component ranged from ≥33 to ≥43 ps. The dynamics correlate with ion concentration, according to radial distribution functions calculated from molecular dynamics simulations, suggesting that local ion densities, regardless of valency or sign, slow dynamics. Results show solvation, electric double layer formation, and monolayer reorientation. This work reveals how electrolyte composition modulates molecular reorientation and hydrogen bonding at functionalized electrodes.M.T.Z - National Science Foundation (NSF) CHE-2314378 M.C. - Institute for Basic Science (IBS) IBS-R023-D1 A.A.K. - National Institutes of Health (NIH) R35GM15096
Toward Sustainable Materials: From Lignocellulosic Biomass to High-Performance Polymers
No full textThis article was originally published in Accounts of Materials Research. The version of record is available at: https://doi.org/10.1021/accountsmr.4c00359.
Copyright © 2025 The Authors. Co-published by ShanghaiTech University and American Chemical Society.
This publication is licensed under CC-BY-NC-ND 4.0 (https://creativecommons.org/licenses/by-nc-nd/4.0/).Conspectus
Lignocellulosic biomass is an ideal feedstock for the next generation of sustainable, high-performance, polymeric materials. Although lignin is a highly available and low-cost source of natural aromatics, it is commonly burned for heat or disposed of as waste. The use of lignin for new materials introduces both challenges and opportunities with respect to incumbent petrochemical-based compounds. These considerations are derived from two fundamental aspects of lignin: its recalcitrant/heterogeneous nature and aromatic methoxy substituents. This Account highlights four key efforts from the Epps group and collaborators that established innovative methods/processes to synthesize polymers from lignin deconstruction products to unlock application potential, with a particular focus on the polymerization of biobased monomer mixtures, development of structure–property–processing relationships for diverse feedstocks, functional benefits of methoxy substituents, and scalability of lignin deconstruction.
First, lignin-derivable polymethacrylate systems were probed to investigate the polymerization behavior of methacrylate monomers and predict thermomechanical properties of polymers from monomer mixtures. Notably, the glass transition temperatures (Tgs) of lignin-derivable polymethacrylates (∼100–200 °C) were comparable to, or significantly above, those of petroleum-based analogues, such as polystyrene (∼100 °C), and the Tgs of the complex, biobased copolymers could be predicted by the Fox equation prior to biomass deconstruction.
Second, an understanding of structure–property relationships in polymethacrylates was applied to create performance-advantaged pressure-sensitive adhesives (PSAs) using phenolic-rich bio-oil obtained from the reductive catalytic fractionation of poplar wood. The use of actual lignin-derived monomers as the starting material was an important step because it underscored that nanostructure-forming, multiblock polymers could be readily made despite the complexity of real lignin deconstruction products. This work also highlighted that lignin-based phenolics could be used to make colorless/odorless PSAs, without complex separations/purifications, and still perform as well as commercial adhesives.
Third, an intensified reductive catalytic deconstruction (RCD) process was developed to deconstruct lignin at ambient conditions, and the deconstructed products were successfully employed in 3D printing. The reactive distillation-RCD process operated at ambient pressure using a low-volatility and biobased solvent (glycerin) as a hydrogen donor, which reduced capital/operating costs, energy use, and safety hazards associated with conventional RCD. Technoeconomic analysis showed that such optimization could lead to a 60% reduction in cost to make the PSAs described above.
Fourth, lignin-derivable bisguaiacols/bissyringols were explored as potential alternatives to petroleum-derived bisphenol A (BPA) in diamine-cured epoxy resins. A distinguishing feature of the lignin monomers (vs. BPA/bisphenol F [BPF]) was the presence of methoxy groups on the aromatic rings, and these methoxy moieties enabled tuning of application-specific properties, such as Tg, degradation temperature (Td), and glassy storage modulus (E′), to achieve improved processing and performance. The lignin-derivable thermosets exhibited Tgs above 100 °C, Tds above 300 °C, and E′s above 2 GPa, all values that were comparable to those of BPA-/BPF-based analogues. Moreover, the methoxy groups on these lignin-derivable compounds sterically hindered hormone receptor binding and could mitigate many of the toxicity concerns associated with BPA/BPF.
This Account concludes with suggestions on future research needed to advance lignin-derived materials as sustainable and performance-advantaged alternatives by leveraging recycling/upcycling strategies and scaling-up/commercializing biomass waste.The authors thank the Army Research Office under Cooperative Agreement Number W911NF-22-2-0257 and the National Science Foundation (NSF) Growing Convergence Research program (NSF GCR CMMI 1934887) in Materials Life Cycle Management for financial support during the writing of this manuscript. The authors are grateful to current and past Epps group members and collaborators for their contributions to the work discussed in this Account. The views and opinions of the authors expressed herein do not necessarily reflect those of the Army Research Office or NSF. Parts of Figure 1 were created in BioRender. Mahajan, J. (2025) https://BioRender.com/v21v441
Leading organizational change: cultivating sustainability in the continuous sustainability approach
No full textVanGronigen, Bryan A.The Delaware Institute for Excellence in Early Childhood (DIEEC) is an organization dedicated to supporting early childhood professionals working in ever-evolving early childhood systems. One strategy that DIEEC uses to support this work is through technical assistance offered by the DIEEC technical assistant (TA) team. Based on new research conducted in the last 15 years, the approach used by the TA team has changed from a more directive approach to one I term the continuous quality improvement (CQI) approach. The CQI approach entails TAs using data and reflection to guide quality improvement planning for early childhood professionals in their growth (Garet et al., 2021; Hatcher et al., 2020; Yurkofsky, 2022). ☐ In this work, I consider the DIEEC TA team to be change agents. Changing a change agent’s approach can be difficult, and the sustained use of the CQI approach by the TA team and DIEEC as a whole has yet to be achieved. This problem, which is that there is too little sustained practice of the CQI approach, is the focus of this Education Leadership Portfolio (ELP). In this ELP, I sought to attain a better understanding of the leader’s role in supporting change at both the individual level (e.g., TA) and the team level (e.g., the TA team). Leaders must understand and apply leadership practices recommended by change management research to guide sustainable organizational change, meaning the change is implemented and sustained over a longer period of time (Gilley et al., 2008). In order to support individuals in aligning with a new organizational change, leaders must be intentional in their plans to support the individuals undergoing such change (Banerjee, 2015; Hao & Yazdanifard, 2015; Thompson, 2019). ☐ To consider this literature with respect to this ELP, I worked to gain deeper insight into how leaders can support an individual during various stages of change while maintaining a strong organizational culture in a dynamic work environment shaped by stakeholders like the Delaware Department of Education (DDOE). I developed this deeper understanding by implementing three improvement strategies: (a) understanding DIEEC staff member’s CQI use and alignment with DIEEC’s mission and vision, (b) exploring the leadership and administration (L&A) TA identities regarding the CQI approach, and (c) fostering alignment between L&A TAs’ identities and CQI-related work. I developed nine artifacts to implement these strategies, including a literature review and original data collection via a survey and a focus group. My culminating artifact used all data from the first eight artifacts to formulate an action plan for the ongoing improvement of the organizational problem after this ELP’s completion.University of Delaware, School of EducationD.Ed
BUFFALO BILLS COMMUNITY COMPLEX
No full textMISSION:
The mission behind this project is to honor the legacy of the old stadium, a symbol of the Buffalo community, by transforming it into a community complex for all residents of greater Buffalo. This project seeks to preserve and bolster the spirit this site holds for current and future generations to enjoy for decades to come.
GOALS:
- Transform the site to preserve its status as a community hub.
- Increase vegetation and pervious surfaces in the primary active core.
- Increase circulation throughout the site.
- Increase accessibility to the site for all members of the community through the revitalization of the nearby rail corridor.Wik, AnnaZimmerman, Jame