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This study investigates the tribological performance and wear mechanisms of graphite and polydopamine/graphite (PDA/graphite) coatings on stainless steel under dry sliding conditions. While graphite is widely used as a solid lubricant, its poor adhesion to metal substrates limits long-term durability. Incorporating an adhesion-promoting PDA underlayer significantly improved coating lifetime and wear resistance. Tribological testing revealed that PDA/graphite coatings maintained a coefficient of friction (COF) below 0.15 for over seven times longer than graphite-only coatings. High-resolution scanning electron microscopy, SEM, and profilometry showed that PDA improved coating adhesion and suppressed lateral debris transport, confining wear to a narrow zone. Surface and counterface analyses confirmed enhanced graphite retention and formation of cohesive transfer films. Raman spectroscopy indicated only modest changes in the D and G bands. X-ray Photoelectron Spectroscopy, XPS analysis, confirmed that coating failure correlated with the detection of Fe and Cr peaks and oxide formation. Together, these results demonstrate that PDA enhances interfacial adhesion and structural stability without compromising lubrication performance, offering a strategy to extend the durability of carbon-based solid lubricant systems for high-contact-pressure applications. 

The development of efficient and cost-effective catalysts for hydrogen evolution reaction (HER) is crucial for the advancement of electrochemical water splitting technology. Here, we report a novel synthetic method for the preparation of single-crystalline NiCoP nanorods with tunable aspect ratios using a CO-assisted, trioctylphosphine (TOP)-mediated approach. The introduction of CO gas at different temperatures allows for the control of the nanorod growth, resulting in various aspect ratios while maintaining a hexagonal crystal structure and a composition of 1:1 Ni/Co as NiCoP. Our results demonstrate that the NiCoP nanorods with higher aspect ratios exhibit improved HER activity and stability, with the highest aspect ratio nanorods showing the lowest overpotential and Tafel slope in both acidic and alkaline media. This study highlights the importance of controlling the size and morphology of bimetallic phosphide nanoparticles to optimize their catalytic activity for HER, providing new insights into the design and optimization of nanostructured catalysts for electrochemical water splitting applications. 

Abstract A growing body of research suggests that digital multimodal composing can provide students multiple points of entry for making sense of local climate change issues and sharing their voices through digital activism. Building upon this scholarship, this study examined the processes of 32 small groups (n= 55) of 7th- and 8th-grade students as they co-created a wide range of multimodal projects (e.g., videos, podcasts, infographics, posters, and cartoons) that explored the environmental, ecological, and sociopolitical impacts of inequitable access to urban tree canopy and greenspace in their city. In particular, scholarship on onto-epistemic heterogeneity, critical place-based learning, and multimodality were integrated to gain an interdisciplinary understanding of how digital multimodal composing mediated students’ sensemaking about urban forestry impacts on community health and ecological well-being. Data sources consisted of field notes, audio and video recordings, survey data, student interviews, and students’ final multimodal projects. Through qualitative and multimodal data analysis, five main themes emerged for how multiple modes mediated students’ sensemaking about critical urban forestry: (1) embracing tree equity for compelling stories, (2) engaging authentic audiences through storytelling, (3) perspective-taking through multiple modes, (4) exploring affective dimensions of urban heat islands, and (5) developing solutions for critical urban forestry issues. These findings contribute new insights into how digital multimodal storytelling can provide a productive way for students to make sense of climate justice issues and gain agency by experiencing multiple ways of knowing. 

Bent DNA amplifying sensors were recently developed to amplify and quantify the interactions of DNA with various salts and molecules. However, a thorough quantitative understanding of their mechanism is missing. Here, using all-atom molecular dynamics (MD) simulations, we investigate the behavior and dynamics of sharply bent DNA molecules in the absence and presence of Mg2+ ions at different concentrations. The simulations show that Mg2+ ions reduce the fluctuations of DNA strands, enhance base-pairing, and stabilize bent DNA molecules. The computational results are further verified by both melting curve experiments and ensemble FRET measurements, highlighting the mechanical instability and sensitivity of bent DNA molecules. 

Abstract. The hydrology of thawing permafrost affects the fate of the vast amount of permafrost carbon due to its controls on waterlogging, redox status, and transport. However, regional mapping of soil water storage in the soil layer that experiences the annual freeze-thaw cycle above permafrost, known as the active layer, remains a formidable challenge over remote arctic regions. This study shows that Interferometric Synthetic Aperture Radar (InSAR) observations can be used to estimate the amount of soil water originating from the active layer seasonal thaw. Our ALOS InSAR results, validated by in situ observations, show that the thickness of the soil water that experiences the annual freeze-thaw cycle ranges from 0 to 75 cm in a 60-by-100-km area near the Toolik Field Station on the North Slope of Alaska. Notably, the spatial distribution of the soil water correlates with surface topography and land vegetation cover types. We found that pixel-mismatching of the topographic map and radar images is the primary error source in the Toolik ALOS InSAR data. The amount of pixel misregistration, the local slope, and the InSAR perpendicular baseline influence the observed errors in InSAR Line-Of-Sight (LOS) distance measurements non-linearly. For most of the study area with a percent slope of less than 5%, the LOS error from pixel misregistration is less than 1 cm, translating to less than 14 cm of error in the soil water estimates. 

Abstract. The hydrology of thawing permafrost affects the fate of the vast amount of permafrost carbon, due to its controls on waterlogging, redox status, and transport. However, regional mapping of soil water storage in the soil layer that experiences the annual freeze–thaw cycle above permafrost, known as the active layer, remains a formidable challenge over remote Arctic regions. This study shows that interferometric synthetic aperture radar (InSAR) observations can be used to estimate the amount of soil water originating from the active-layer seasonal thaw. Our ALOS InSAR results, validated by in situ observations, show that the equivalent thickness of the soil water that experiences the annual freeze–thaw cycle ranges from 0 to 75 cm in a 60 km×100 km area near the Toolik Field Station on the North Slope of Alaska. Notably, the spatial distribution of the soil water correlates with surface topography and land vegetation cover types. We found that pixel-mismatching of the topographic map and radar images is the primary error source in the Toolik ALOS InSAR data. The amount of pixel misregistration, the local slope, and the InSAR perpendicular baseline influence the observed errors in InSAR line-of-sight (LOS) distance measurements. For most of the study area with a percent slope of less than 5 %, the LOS error from pixel misregistration is less than 1 cm, translating to less than 14 cm of error in the soil water estimates.