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Can UVC-LEDs mitigate biofouling in community-scale photovoltaic-powered reverse osmosis systems?

Water Supply 2025年第4期25卷 779-791页

作者： Karim, N.S. Sarker, N.R. Asker, D. Hatton, B. Bilton, A.M. Water and Energy Research Lab Department of Mechanical & Industrial Engineering University of Toronto 5 King's College Rd TorontoONM5S 3G8 Canada Functional and Adaptive Surfaces Laboratory Department of Materials Science & Engineering University of Toronto Toronto Canada Food Science & Technology Department Alexandria University Alexandria21545 Egypt

The lack of safe drinking water infrastructure in off-grid communities is a significant risk to sustainable development, especially for low- and middle-income countries (LMICs). Photovoltaic-powered reverse osmosis (PVRO) has emerged as a promising method due to its performance, scalability, consistency, and the robust global supply chain of its components. However, reliability issues like biofouling can quickly reduce its performance, shorten membrane lifetime, and hinder adoption in off-grid settings. Ultraviolet light emitting diodes (UV-LEDs) ranging from 200–285 nm wavelengths reduce the number of microorganisms in water but there are mixed results about their use on mitigating biofouling in reverse osmosis systems. Herein, we aim to provide a preliminary assessment on whether UV-LED pre-treatment can mitigate biofouling in PVRO systems. Analysis of the E. coli concentration pre- and post-UV treatment for batch and flow cell experiments demonstrated reduced bacterial concentration after treatment but suggest that remaining bacteria after UV treatment can grow back over time, i.e., UV-LEDs do delay, but not completely eliminate, biofouling. These results encourage further investigation into how UV-LEDs can be optimally integrated in PVRO systems and also set the premise for controlled biofouling mitigation studies for intermittently operated, small-scale PVRO. © 2025 The Authors.

关键词： Light emitting diodes

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High-temperature tribological properties of tungsten carbide reinforced high-entropy-alloy composite coating by laser cladding

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Ceramics International 2025年第14期51卷 19485-19496页

作者： Wu, Wenxing Liu, Hanxia Jin, Xuming Guo, Liangliang Zhu, Tao Hu, Liangbin Yang, Chao Chen, Pinghu Qiu, Changjun Chu, Paul K. College of Nuclear Science and Technology University of South China Hengyang421001 China School of Electrical Engineering University of South China Hengyang421001 China Key Laboratory of Hunan Province of Equipment Safety Service Technology Under Extreme Environment College of Mechanical Engineering University of South China Hengyang421001 China National Engineering Research Center of Light Alloy Net Forming School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai200240 China Department of Materials Science & Engineering City University of Hong Kong Tat Chee Avenue Kowloon999077 China

To solve the serious wear problem of mold steels at a high temperature, a 15 wt% WCp (Tungsten Carbide particles) reinforced Fe50Mn30Cr10Co10 HEA (High Entropy Alloy) composite coating is fabricated by laser cladding to improve the high-temperature wear resistance based on high hardness and thermal stability of HEA. Tribological tests are carried out at different temperature, and the wear mechanism is explored. The experimental results reveal three main phases of γ-Fe, WC, and W2C in the LCed (Laser Cladded) HEA composite coating. Small amounts of nanoscale WC and MnO are precipitated to enhance the mechanical properties. The variation rule pertaining to the volume wear rate is that the values rise first and fall later with increasing temperature. The maximum wear rate is observed above 5 × 10−5 mm3/N·m at 400 °C. Although the hardness may diminish with increasing temperature in theory, the relative wear resistance can be improved because the oxide could enhance the supportive capacity and isolating effects of the glaze layer between the friction pair. Fe2O3 can be considered a solid lubricant to reduce the wear rate. With increasing friction temperature, the wear mechanism changes from typical abrasive/fatigue wear to adhesive/delamination wear. Consequently, the 15 wt% WCp-reinforced HEA composite shows excellent wear resistance at 800 °C relative to H13 steel and the results provide the theoretical and experimental basis for liquid die forging. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Composite coatings

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Anomalous properties of spark plasma sintered boron nitride solids

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materials Today 2025年 86卷 42-51页

作者： Biswas, Abhijit Serles, Peter Alvarez, Gustavo A. Schimpf, Jesse Hache, Michel Kong, Jonathan Demingos, Pedro Guerra Yuan, Bo Pieshkov, Tymofii S. Li, Chenxi Puthirath, Anand B. Gao, Bin Gray, Tia Zhang, Xiang Murukeshan, Jishnu Vajtai, Robert Dai, Pengcheng Singh, Chandra Veer Howe, Jane Zou, Yu Martin, Lane W. Clancy, James Patrick Tian, Zhiting Filleter, Tobin Ajayan, Pulickel M. Department of Materials Science and Nanoengineering Rice University HoustonTX77005 United States Department of Mechanical & Industrial Engineering University of Toronto 5 King's College Road TorontoM5S 3G8 Canada Sibley School of Mechanical and Aerospace Engineering Cornell University IthacaNY14853 United States Department of Materials Science and Engineering University of California Berkeley94720 United States Department of Materials Science and Engineering University of Toronto 184 College St TorontoM5S 3E4 Canada Department of Physics and Astronomy McMaster University HamiltonL8S 4M1 Canada Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Department of Physics and Astronomy Rice University HoustonTX77005 United States Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley94720 United States

Hexagonal boron nitride (h-BN) is a brittle ceramic with a layered structure, however, recent experiments have suggested that inter-layer structural engineering could be key to new structural and functional properties. Here we report the scalable bulk synthesis of high-density crystalline h-BN solids, by using high-temperature spark plasma sintering (SPS) of h-BN powders, which show high values of mechanical strength, ductility, dielectric constant, thermal conductivity, and exceptional neutron radiation shielding capability. Through exhaustive characterizations we reveal that SPS induces non-basal plane crystallinity, twisting of layers, and facilitates inter-grain fusion with a high degree of in-plane alignment across macroscale dimensions, resulting in near-theoretical density and improved properties. Our findings highlight the importance of material design, via new approaches such as layer twisting and interlayer interconnections, to create novel ceramics with properties that could go beyond their intrinsic limits. © 2025

关键词： Ductility

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Selection of a suitable wear-resistant metal matrix composite for remanufacturing continuous miner cutter (CMC) sleeves via a two-step laser-based technique

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CIRP Journal of Manufacturing science and Technology 2025年 60卷 165-181页

作者： Lindsay, Emmanuel Efemena Akintunde, Idris Babatunde Olakanmi, Eyitayo Olatunde Prasad, Raghupatruni Ventaka Satya Botes, Annelize Pityana, Sisa Lesley Skhosane, Samuel Department of Mechanical Energy & Industrial Engineering Botswana International University of Science & Technology Palapye Botswana Team Botswana International University of Science & Technology Palapye Botswana Research Group Botswana International University of Science & Technology Palapye Botswana Department of Chemical Materials and Metallurgical Engineering Botswana International University of Science & Technology Palapye Botswana Department of Materials & Metallurgical Engineering Federal University of Technology Minna Nigeria Department of Mechanical Engineering Nelson Mandela University Port-Elizabeth South Africa Laser-Enabled Manufacturing Research Group Council for Scientific & Industrial Research Pretoria South Africa

The premature failure of continuous miner cutter (CMC) sleeves in underground coal mining necessitates remanufacturing to enable a closed-loop system and enhanced sustainable mining operations. However, a techno-economic analysis conducted revealed that exclusively using laser cladding (LC) to remanufacture failed sleeves is not economically viable. Thus, this research aims to explore a two-step laser-based remanufacturing technique that incorporates gas metal arc welding (GMAW) and LC, as well as identify suitable wear-resistant metal matrix composites (MMCs) for restoring damaged sleeves. Consequently, an LC process was used to deposit three MMC materials onto optimised GMAW overlays. A comparative analysis of the manufactured MMC coatings revealed that WC/TiC/AISI4340 coating exhibited a well-consolidated, crack- and pore-free microstructure and a superior microhardness of 931 HV0.5 compared to WC- and TiC-reinforced composites, which had average hardness values of 670 HV0.5 and 744 HV0.5, respectively. Additionally, the WC/TiC/AISI4340 coating demonstrated an excellent low wear rate (0.0007 g/s) comparable to TiC-reinforced coating, and a propensity to extend the sleeve's lifespan by a factor of four. These enhancements are attributed to the formation of an umbrella-like network of TiC, predominantly distributed in the coating top region and solid solution strengthening [(Ti, W)C] caused by the partial dissolution of WC/TiC carbides and their precipitation into the eutectic carbide network within the interdendritic grain regions. Hence, combining GMAW and LC processes with WC/TiC/AISI4340 presents a promising remanufacturing strategy for restoring mining equipment, offering improved performance, longer lifespan, and economically viable and sustainable mining operations. © 2025 Elsevier Ltd

关键词： Laser cladding

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Pressure-induced nano-crystallization and high hardness of optically transparentα-Si_(3)N_(4) ceramics

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science China(Physics,Mechanics & Astronomy) 2025年第5期68卷 183-191页

作者： Shuailing Ma Wei Li Xiaoqi Zhang Kathy Lu Min Lian Xinmiao Wei Yilong Pan Hai Jiang Hongwei Wang Zihan Zhang Qiang Tao Tian Cui Ralf Riedel Pinwen Zhu Institute of High-Pressure Physics School of Physical Scientific and TechnologyNingbo UniversityNingbo 315211China Synergetic Extreme Condition High-Pressure Science Center State Key Laboratory of Superhard MaterialsCollege of PhysicsJilin UniversityChangchun 130012China Department of Mechanical and Materials Engineering University of Alabama at BirminghamBirmingham AL 35294USA Department of Materials and Earth Sciences Technical University of DarmstadtDarmstadt 64287Germany

Transparent silicon nitride ceramics with good optical and mechanical properties are promising ceramics for scientific and industrial window materials with a long service *** optical transparency and mechanical strength will be substantially enhanced in dense nano-polycrystalline ***,the synthesis of nano-polycrystallineα-Si_(3)N_(4) has not been realized due to the limitations of conventional sintering ***,nano-polycrystallineα-Si_(3)N_(4) was prepared by direct conversion of micron-grain silicon nitride without additives under high-pressure conditions of 5 GPa and a limited temperature range 1650°C-1700°*** micron-sized grains undergo grain refinement and recrystallization to form uniform nano-grains under high pressure and high ***,transparentα-Si_(3)N_(4) samples exhibit the highest Vickers hardness of 26.7 GPa,which is far higher than that of specimens with or without additives used in other sintering methods(e.g.,SPS,and HP).According to the Hall-Petch and Taylor dislocation hardening effects,the refined nano-grains,coherent grain boundaries,and high dislocation density lead to high ***,the high density,nanoscale grains,and fine grain boundaries are ascribed to the improvement of ***-pressure sintering induces grain refinement,grain coherency,and increased dislocation in silicon nitrides,thus providing a promising method for preparing advanced transparent ceramic windows in the future.

关键词： silicon nitride high pressure and high temperature transparent ceramics hardness

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Self-organization in a stably stratified, valley-shaped enclosure heated from below

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Physical Review Fluids 2025年第1期10卷 014402-014402页

作者： Patrick J. Stofanak Cheng-Nian Xiao Inanc Senocak Department of Mechanical Engineering and Materials Science University of Pittsburgh Pittsburgh Pennsylvania 15261 USA

We observe the spontaneous onset of three-dimensional motion from a quiescent, purely conductive state of a stably stratified fluid in a V-shaped enclosure heated from below, which ultimately self-organizes into a two-dimensional steady state without any external forcing to the initial configuration. We identify a dominant three-dimensional instability through modal stability analysis. Direct numerical simulations confirm this instability but also reveal that, after an initial period of spontaneous three-dimensional growth, the flow gradually self-organizes into a steady two-dimensional state without external intervention. This self-organization manifests consistently for any arbitrary infinitesimal three-dimensional disturbance to the initial quiescent configuration. We demonstrate that the mechanism driving this self-organization is the increasing dominance of viscous dissipation over buoyant production of disturbance kinetic energy at later stages of flow evolution from the initial quiescent state. Our investigation reveals a flow scenario in which the most natural transition pathway to the final state involves passing through an intermediate state with a higher dimension than the final state itself. Specifically, our final flow state is less complex than the three-dimensional most unstable eigenvector predicted by linear-stability analysis. We demonstrate that the entire flow evolution remains nonturbulent throughout and closely aligns with results from linear-stability analysis, distinguishing the present flow dynamics from transient chaos, which also features complex transient states that eventually converge to a less complex final state.

关键词： Kinetic energy

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Electrochemical Characterization of Hot-Dip Galvanized (HDG) Coatings of Zinc-Aluminum and Zinc-Nickel Alloys

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Journal of materials engineering and Performance 2025年 1-14页

作者： Ferrel-Alvarez, A.C. Lu, Yi Ashok, A. Subramaniam, V. Castaneda, H. Department of Materials Science and Engineering Texas A & M University College StationTX United States Department of Mechanical Engineering Texas A & M University College StationTX United States Instituto de Física Universidad Nacional Autónoma de México México City04510 Mexico

This study investigated the effect of zinc (Zn) with alloy elements applied via the hot-dip galvanized method on the corrosion protection of carbon steel substrates. The alloy layers consisted of Zn plus nickel (Ni) and aluminum (Al) incorporated at varying weight percentages (wt.%) under a constant temperature of 450 °C. The influence of alloying elements on the Zn alloys was assessed through electrochemical and microstructural analyses, and fog chamber characterization. Electrochemical characterization conducted after 40 days indicated that, among the Zn-Al samples, 0.0045 wt.% Al composition exhibited the highest resistance, at 10 kΩ-cm2, whereas for the Zn-Ni samples, a 0.0065 wt.% Ni composition demonstrated the highest resistance, at 16 kΩ-cm2. Notably, the resistance of the Zn alloy galvanized samples was almost four times higher than that of the conventional Zn galvanized samples, and reached a maximum resistance of 4 kΩ-cm2. The effects of corrosion resistance were further observed in a salt fog chamber. Addition of Al and Ni was found to increase the corrosion resistance of the Zn galvanized layer because of the barrier effect and the distribution of corrosion products. © ASM International 2025.

关键词： Corrosion resistant coatings

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Experimental Construction of Mohr–Coulomb Model for Green Sand Mold by Direct Shear Test Eliminating Effect of Wall Friction

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International Journal of Metalcasting 2025年 1-11页

作者： Okimura, Yasuhiko Kumaki, Takumi Yoshida, Hideki Nishi, Kohei Kato, Noriyuki Tokunaga, Koji Hashimoto, Kunihiro Matsuura, Makoto Koroyasu, Sadatoshi Komine, Hideo Maeda, Yasuhiro Okane, Toshimitsu Miyashita, Tomoyuki Yoshida, Makoto Department of Modern Mechanical Engineering Graduate School of Creative Science and Engineering Waseda University Tokyo Shinjuku 169-8555 Japan SINTOKOGIO Ltd Aichi Nagoya 450-6424 Japan Faculty of Science and Engineering Department of Mechanical and Precision Systems Teikyo University Tochigi Utsunomiya 320-8551 Japan Department of Civil and Environmental Engineering School of Creative Science and Engineering Waseda University Tokyo Shinjuku 169-8555 Japan Department of Mechanical Engineering School of Engineering Daido University Aichi Nagoya 457-8530 Japan Faculty of Technologists Department of Manufacturing Technologists Institute of Technologists Saitama Gyoda 361-0038 Japan Department of Modern Mechanical Engineering School of Creative Science and Engineering Waseda University Tokyo Shinjuku 169-8555 Japan Kagami Memorial Research Institute for Materials Science and Technology Waseda University Tokyo Shinjuku 169-0051 Japan Tajima Light Metal Co. Ltd. Saitama Hanyu Japan

This paper performed the direct shear test for a green sand mold to construct the Mohr–Coulomb (MC) model as a mechanical model of the green sand mold, which is essential to predict the casting deformation by computer simulation. It is generally known that the pressure loaded on the test piece is not fully transmitted to its shear plane in the direct shear test because of the friction between the test piece and the shear box. A previous study estimated the vertical stress on the shear plane from the pressure transmission coefficient measured when the test piece was not sheared. However, this method ignored the change in the value and direction of the wall friction due to the dilatancy of the test piece during shearing. The present paper determines the values of the material constants in the MC model by two methods: by eliminating the effect of the wall friction during shearing and by ignoring that effect. In the prior method, the vertical stress on the shear plane is directly measured throughout the test by the load cell attached below the test piece. As a result, when the wall friction effect during shearing is not eliminated, the strength of the test piece was evaluated to be twice as large as that obtained eliminating the wall friction effect. With the MC model ignoring the wall friction, the computer simulation to predict the casting deformation will estimate the unrealistically high strength of the mold, leading to an erroneous prediction of the casting deformation. © The Author(s) 2025.

关键词： constitutive modeling deformation direct shear test green sand mold mechanical properties

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Energy Transfer Mechanisms in Large Low-Bandgap Polymers from Time-Resolved Experiments and Nonadiabatic Molecular Dynamics Calculations

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Chemistry of materials 2025年第10期37卷 3769-3775页

作者： Phun, Gabriel S. Kern, Dana B. Sfeir, Matthew Y. Azoulay, Jason D. Wong, Bryan M. Department of Chemistry Department of Physics & Astronomy Materials Science & Engineering Program University of California-Riverside Riverside 92521 CA United States School of Chemistry and Biochemistry School of Materials Science and Engineering Center for Organic Photonics and Electronics Georgia Institute of Technology Atlanta 30332 GA United States Materials Science Center National Renewable Energy Laboratory Golden 80401 CO United States

Conjugated polymers offer unprecedented chemical tunability for modulating energy transfer in a multitude of infrared light applications. In this work, we use a combination of time-resolved spectroscopic experiments and nonadiabatic molecular dynamics calculations to probe the photochemistry and nonradiative transitions in a recently synthesized narrow bandgap donor-acceptor conjugated polymer based on alternating cyclopentadithiophene and electronegative benzothiadiazole heterocycles. Using large-scale semi-empirical nonadiabatic molecular dynamics, which can treat a large 260-atom hexamer, we calculate an S₅ → S₁ lifetime of 34.75 fs, which is consistent with our time-resolved spectroscopic data. Our simulations suggest that vibronic motions of the central carbons in the cyclopentadithiophene functional groups are predominantly involved in the nonradiative transitions, and the excitation becomes more localized on a monomer fragment over time. The combined use of time-resolved experiments and nonadiabatic molecular dynamics calculations in this work provides mechanistic insight into chemical functionalities that can be tuned to enhance energy transfer in other prospective low-bandgap polymer materials. © 2025 The Authors. Published by American Chemical Society.

关键词： Spectroscopic analysis

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GeoRefineNet: A Multistage Framework for Enhanced Cephalometric Landmark Detection in CBCT Images Using 3D Geometric Information 17th

GeoRefineNet: A Multistage Framework for Enhanced Cephalome...

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17th Asian Conference on Computer Vision, ACCV 2024

作者： Viriyasaranon, Thanaporn Ma, Serie Choi, Jang-Hwan Department of Computational Medicine Graduate Program in System Health Science and Engineering Ewha Womans University Seoul Korea Republic of Division of Mechanical and Biomedical Engineering Graduate Program in System Health Science and Engineering Ewha Womans University Seoul Korea Republic of Department of Artificial Intelligence Ewha Womans University Seoul Korea Republic of

ISBN: (纸本)9789819609000

The precise detection of cephalometric landmarks on two-dimensional (2D) radiographs or three-dimensional (3D) computed tomography (CT) images is a fundamental step in various medical fields, especially in research on orthodontics and maxillofacial surgery. Deep learning-based detectors have demonstrated remarkable accuracy in 2D cephalometric analysis, whereas conventional single-view approaches are limited by their reliance on information from a single perspective. This study proposes GeoRefineNet, a novel multistage framework that leverages information from multiple CT scans acquired at various angles. By incorporating geometric knowledge through a 3D heatmap reconstruction process, GeoRefineNet improves robustness, accuracy, and adaptability to various cephalometric configurations. The proposed framework predicts 3D landmark positions on CT images, effectively addressing challenges associated with high-dimensional input data and limited training examples. GeoRefineNet surpasses the existing state-of-the-art models in the 2D and 3D domains, as demonstrated by its superior performance on numerical and clinical datasets. These findings indicate that GeoRefineNet offers a promising avenue for improving the accuracy and reliability of cephalometric landmark detection fostering further advances in clinical diagnosis and treatment planning. Our code is available at https://***/Thanaporn09/***. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.

关键词： Computerized tomography

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