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Careful how you teach: Massive Open Online Courses (MOOCs), critical media literacy and misinformation
(2026) Chauhan, Saurabhsinh; Hoechsmann, Michael
Formation of one- and two-dimensional molecular networks on metal surfaces
(2026) Niya, Hamzeh Nakhaei; Ebrahimi, Maryam; Gallagher, Mark; Liao, Baoqiang; MacKinnon, Craig; Lopinski, Greg
The on-surface synthesis of one- and two-dimensional (1D and 2D) organic nanostructures on metal single crystal surfaces was studied under ultra-high Vacuum conditions. Two different organic molecules were investigated on metal substrates using scanning tunneling microscopy (STM). The first study focuses on the adsorption of Br4Py molecules (a molecule with a pyrene core and four bromine atoms in each corner) onto the Au(111) surface at room temperature. The STM images reveal that the molecules formed a 2D self-assembled network which is stable after stepwise annealing up to 400 K. After annealing at 425 K, two different structures are resolved by STM, one of which indicates an on-surface reaction. The second organic molecule, 4,4',4",4"'-(Pyrene-1,3,6,8-tetrayl) tetra-benzaldehyde (PTTA), also has a pyrene core, with four benzaldehyde groups as arms. PTTA was studied on Au(111) and Ag(111). It should be noted that the low coverage and high coverage experiments on Au(111) were performed in two different ultra-high vacuum systems at and imaged at different temperatures. At low coverage, room-temperature deposition yields a mixture of 1D and 2D molecular arrangements. The 2D networks consist of a combination of a “stacked” 2D close-packed selfassembled structure as well as those with the addition of molecular vacancies. At high coverage, room-temperature deposition leads to a “staggered” 2D close-packed self-assembled network. Density functional theory calculations yield a total stabilization energy of - 4.57 eV/molecule for the staggered 2D structure and - 3.81 eV/molecule for the stacked 2D network, formed at high and low coverage, respectively. The energies indicate that the stacked 2D structure is thermodynamically the more preferred 2D structure. Annealing the high coverage sample to 350 K leads to the formation of a molecular bilayer. After post-annealing low coverage samples to 450 K, STM images indicate a change in the appearance of the resolved features in the 1D structures, by a reduction in the intermolecular spacing along the chain direction. This transformation suggests a chemical change in the 1D structure affording (short range) molecular chains. Similarly, STM image analysis reveals a change in the appearance of 2D molecular features. A reduction in the unit cell dimensions and/or change in the ordering of the stacked and staggered 2D close-packed structures is observed. The changes in the 1D and 2D structures suggests chemical changes in the network in line with the McMurry-like condensation reaction of aldehyde on Au(111). On Ag(111), room temperature deposition of PTTA yields a staggered 2D close-packed selfassembled network. After post-annealing to 375 K, STM images reveal a change in appearance of some of the features in the 2D network and the molecules shifted closer to one another and at some regions intermolecular linkages were observed. After annealing at 400 K, a change in the ordering of the staggered 2D close-packed structure was observed. As on Au the changes in the 2D structure suggests chemical changes in the network.
Can dominant species traits and soil chemistry explain stability in Kalmia heath?
(2026) Wiens, Justin; Mallik, Azim; Algar, Adam; Rennie, Michael
In eastern Canada, black spruce (Picea mariana)-Kalmia angustifolia forests exist in one of three states: Kalmia heath, shrub savanna (SS), and black spruce forest. My main objective was to determine whether the strength of a plant-soil feedback (PSF) implicating abiotic soil properties distinguishes these three states. It is thought that traits of ericaceous shrubs (recalcitrant litter, low foliar nutrients, and high production of phenolic compounds) create nutrient-poor conditions in Kalmia heath and that this PSF explains long-term black spruce regeneration failure in heath. To test the importance of this PSF, I measured four above-ground Kalmia traits related to litter quality (leaf dry matter content, specific leaf area, foliar C:N, and foliar total phenolics) and six indicators of soil nutrient availability (soil respiration, pH, total N, inorganic N, organic N to inorganic N ratio, and total phenolics) at eight sites in and around Terra Nova National Park, Newfoundland, Canada. The eight sites consisted of four vegetation types, which were, in order of least to most spruce dominance and post-fire spruce canopy expansion, Kalmia heath, early-stage SS (eSS), mature SS (mSS), and black spruce forest. I found that the four vegetation types differed based on Kalmia traits, and that Kalmia litter quality increased from heath to eSS, to mSS, to forest. I also found that forest had higher soil nutrient availability than heath, eSS, and mSS. This means that the strength of a PSF creating nutrient-poor soil was weaker in the forest than in the other vegetation types. Contrary to expectation, the heath, eSS, and mSS vegetation types were not different based on the soil nutrient availability indicators measured. Therefore, a PSF involving the abiotic soil properties measured here did not explain the improved black spruce colonisation success in SS compared to Kalmia heath.
Sulfobutylated lignin/polyaniline hybrid cathodes to enhance redox stability for lithium-ion batteries
(2026) Aidoo, Enoch; Fatehi, Pedram; Kang, Kang; Djafaripetroudy, Seyed Rahman
The global transition toward sustainable energy systems has intensified the search for electrode materials that combine high electrochemical performance with environmental compatibility. Conventional inorganic cathodes, while effective, rely on scarce or toxic elements and present challenges in recyclability and cost. Organic polymers, by contrast, offer structural tunability, lightweight composition, and potential renewability, but their practical application has been hindered by poor conductivity, limited cycling stability, and thermal degradation. Lignin, the most abundant aromatic biopolymer on Earth and a major by‑product of the pulp and paper industry, represents a promising candidate for sustainable electrode design. Its aromatic backbone, rich in functional groups, provides opportunities for chemical modification and integration with conductive polymers. This study explores the rational modification of lignin through sulfobutylation and its subsequent incorporation into polyaniline (PANI) composites to develop bio‑based cathode materials for lithium‑ion batteries. The primary objective of this research was to establish a direct structure–property relationship between lignin’s charge density, polymer integration, and electrochemical stability. Sulfobutylated lignin–polyaniline (SBLP) composites were synthesized with varying degrees of sulfobutylation, yielding SBLP2.0 and SBLP2.5 formulations. The –SO₃⁻ groups introduced by sulfobutylation acted as fixed ionic charge sites, stabilizing the emeraldine form of PANI and promoting Li⁺ transport. In addition, π–π stacking and hydrogen bonding interactions between lignin and PANI enhanced structural flexibility, facilitating chain rearrangement during charge/discharge cycles. These synergistic effects were hypothesized to improve conductivity, reduce polarization, and strengthen pseudocapacitive contributions relative to pristine polyaniline. Comprehensive characterization was performed to validate these hypotheses. Thermogravimetric analysis (TGA) confirmed improved thermal stability of the composites compared to pristine PANI, addressing a critical limitation of organic electrode materials. X‑ray diffraction (XRD) and Brunauer–Emmett–Teller (BET) surface area analysis revealed enhanced porosity and structural order in the SBLP composites, supporting improved ion accessibility. Electrochemical evaluation included cyclic voltammetry (CV), galvanostatic charge–discharge cycling, and rate capability testing under sequential current densities (C/20, C/10, C/2, and return to C/20). The CV profiles of SBLP composites exhibited higher peak currents and broader integrated areas, indicating increased charge‑storage capacity and faster kinetics. Galvanostatic cycling demonstrated clear performance differences: SBLP2.5 delivered the highest initial discharge capacity (≈220 mAh g⁻¹), while SBLP2.0 achieved superior structural reversibility, recovering ~90% of its initial capacity after rate cycling. Pristine PANI, by contrast, suffered pronounced capacity fading and poor recovery (~70%), consistent with its limited conductivity and susceptibility to structural decay in LiPF₆ electrolyte. Quantitative comparison of cycling metrics further highlighted the balanced performance of SBLP2.0, which achieved 80% capacity retention and 95% coulombic efficiency, outperforming both pristine PANI (56% retention, 70% efficiency) and SBLP2.5 (64% retention, 86% efficiency). These results confirm that while higher sulfobutylation increases initial capacity by introducing more ion‑accessible sites, excessive modification can induce structural disorder, segmental swelling, and interfacial strain that compromise long‑term stability. Thus, an optimal degree of sulfobutylation is critical for maximizing both performance and durability. Overall, this thesis demonstrates that rational chemical modification of lignin, combined with conductive polymers, can yield sustainable and electrochemically active cathode materials for next‑generation lithium‑ion batteries. The findings advance the understanding of how lignin’s charge density and polymer interactions govern electrochemical behavior, providing a framework for designing bio‑based composites with tailored properties. Future work will explore alternative lignin derivatives, varied sulfobutylation degrees, and full‑cell configurations to enhance electrochemical durability and scalability further further. By bridging renewable materials chemistry with energy storage technology, this research contributes to the development of greener, more sustainable batteries that align with global energy and environmental goals.
The design and mechanical assessment of a prosthetic foot for transtibial amputees
(2026) Zerpa, Carlos (Jr); Liu, Meilan; Bai, Hao; Salem, Sam
This thesis focuses on the development of an affordable prosthetic foot using 3D modeling. The aim is to provide a more accessible option for the average person. The study includes a detailed examination of the commercial prosthetics currently available on the market. By analyzing existing designs, the research compares their effectiveness with the new design being developed. The project utilizes SolidWorks to design each component and assemble the entire prosthetic foot. Simulations are conducted to assess how an average load affects the heel and forefoot of the design, as well as to determine whether the chosen material effectively reduces impact during walking. In addition to simulations, lab experiments were performed using the Chatillon force tester to analyze various prosthetic designs, including the 3D-printed model. These tests apply the required load to compute data on measures of absorbed energy and stiffness. The study also incorporated a 3Dprinted insole designed to diminish impact during walking. These findings could lead to the creation of more affordable prosthetics, offering greater flexibility and comfort for transtibial amputees.