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Characterization of H2-air detonations with high-speed (2.5 MHz) Rayleigh scattering and single-shot planar laser-induced fluorescence of nitric oxide

Characterization of H2-air detonations with high-speed (2.5 ...

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AIAA science and Technology Forum and Exposition, AIAA SciTech Forum 2025

作者： Chatelain, Karl P. Alicherif, Mhedine Guiberti, Thibault F. Lacoste, Deanna A. Mechanical Engineering Program Physical Science and Engineering Division PO box 4700 Thuwal23955-6900 Saudi Arabia

ISBN: (纸本)9781624107238

This study characterizes a CJ hydrogen-air detonation using high-speed Rayleigh scattering and single-shot planar laser-induced fluorescence of nitric oxide (NO-PLIF). Firstly, we demonstrate that a Nd:YAG laser cluster can be employed to conduct high-speed Rayleigh scattering visualizations of hydrogen-air detonations at 25 kPa, achieving effective visualization frequencies of 2.5MHz in this study. This multipulse Rayleigh scattering diagnostic is complementary to the existing techniques: (i) it enables the characterization of any detonation, from CJ detonations in large aspect ratio channel to marginal detonations in narrow channels;(ii) it is significantly less expensive than typical burst-mode lasers;(iii) it has adjustable visualization frequency, which can go beyond 10MHz with the same energy per pulse. This makes this diagnostic even more suitable for high-pressure detonations or for undiluted conditions, where structures are smaller and detonations faster, respectively;(iv) it is easily applicable to higher initial pressures since the Rayleigh signal scales with number density. Secondly, we combine this multipulse Rayleigh scattering with NO-PLIF to complement the average speed and speed decay measurements with local induction zone length (δi) measurements. This five-beam configuration provides measurement capabilities similar to our previous three beam configuration, outside of the local speed decay. Furthermore, an experimental and numerical assessment reveals that δi measurements cannot be achieved from Rayleigh scattering, as they are significantly underestimated—by approximately 25%—compared to those from NO-PLIF. Hence, NO-PLIF is recommended over Rayleigh scattering for accurate δi measurements in future studies. © 2025, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： Rayleigh scattering

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Sintering-based lithography metal additive manufacturing of chiral mechanical metamaterials with a twist 1

Sintering-based lithography metal additive manufacturing of ...

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1st International Conference on Digital Sovereignty, ICDS 2024

作者： Melentiev, Ruslan Wagih, Ahmed Van Der Heijden, Bram Lubineau, Gilles Grande, Carlos A. Thuwal23955-6900 Saudi Arabia Thuwal23955-6900 Saudi Arabia Mechanical Engineering Program Physical Sciences and Engineering Division Saudi Arabia Thuwal23955-6900 Saudi Arabia Chemical Engineering Program. Physical Science and Engineering Division King Abdullah University of Science and Technology Saudi Arabia

Metamaterials are a cla b of materials with extraordinary capabilities derived from their engineered structure. In 2017, Frenzel et al. (science 358, 2017) conceptualized "three-dimensional mechanical metamaterials with a twist,"which convert linear deformation into rotational motion - a mechanical response that surpa bes the bounds of Cauchy continuum mechanics. However, the lack of suitable manufacturing technologies for producing metallic twist metamaterials has precluded their experimental validation and potential applications to date. Herein, 316L-stainle b-steel twist metamaterials are fabricated at various scales using an emerging sintering-based technology - lithography metal manufacturing (LMM) - and their mechanical responses are tested using stereo digital image correlation. Results provide the first empirical evidence of compre bion-induced rotation in steel twist metamaterials and highlight their sensitivity to manufacturing defects. Video, Application 1 Supplementary 1 Video, Application 2 Supplementary 2 Video, Application 3 Supplementary 3 © 2025 The Author(s).

关键词： Sintering

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Assessment of the wall effects on the cellular structure by combined planar laser-induced fluorescence and Rayleigh scattering

Assessment of the wall effects on the cellular structure by ...

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AIAA science and Technology Forum and Exposition, AIAA SciTech Forum 2025

作者： Alicherif, Mhedine Chavez, Samir B. Rojas Chatelain, Karl P. Guiberti, Thibault F. Lacoste, Deanna A. PO box 4700 Thuwal23955-6900 Saudi Arabia Mechanical Engineering Program Physical Science and Engineering Division King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia

ISBN: (数字)9781624107238

ISBN: (纸本)9781624107238

This study investigates the structure of the detonation front in a stoichiometric H2-air mixture (2H2-O2-3.76N2), seeded with 2000,ppm of NO, at 25,kPa and 293,K, for two channel positions: centered and near thewalls (side). Acombination of NO-PLIF and Rayleigh scattering techniques was used to characterize key features of the detonation front, such as unburned gas pockets, transverse waves, cellular irregularities, and triple point trajectories. The irregular features were categorized into four distinct "events", and their occurrence probabilities were determined for each configuration based on samples of over one hundred detonation cells. The centered configuration showed fewer irregularities with lower probabilities for all events, indicating a regular structure. In contrast, the side configuration showed higher probabilities for all events, indicating a more irregular structure closer to the walls. With the same techniques a correlation between the formation of unburned gas pockets and a local thickening of the front was investigated. While the processes seems to be interconnected in the center of the channel this correlation is lost closer to the walls. The results suggest a strong dependence between the occurrence detonation irregularities and their position relative to the walls. © 2025, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： Rayleigh scattering

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Three-dimensional surface topography analysis of die-sinking electrical discharge machined eco-friendly beryllium-free copper alloys

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International Journal of Advanced Manufacturing Technology 2025年第7期138卷 2911-2953页

作者： Vijayan, Vipin Saju, Kaiprappady Kunchu Sundaresan, Jithin Division of Mechanical Engineering School of Engineering Cochin University of Science and Technology Thrikkakkara Kerala Kochi682022 India Department of Mechanical Engineering Muthoot Institute of Technology and Science Varikoli Kerala Ernakulam682308 India Business Information Systems Program Information Systems Department School of Computing and Creative Arts Bina Nusantara University Senayan DKI Jakarta Jakarta10270 Indonesia

Beryllium-copper alloys, the most widely used copper alloys, are utilised extensively in diverse sectors, including the electrical, electronics, instrumentation, metallurgy, aerospace, automotive, petrochemical, machinery manufacturing, and die and mould-making industries. The main drawback of these alloys is that they produce the toxic component, beryllium oxide, which can lead to a chronic lung disease known as berylliosis. Beryllium-free copper alloys, such as copper-nickel-silicon-chromium, are eco-friendly, less costly, and possess properties similar to those of beryllium-copper alloys. Hence, they are now replacing beryllium-copper alloys in the applications mentioned earlier. Due to their high strength and hardness, these alloys are often fabricated into components using unconventional machining techniques, such as electrical discharge machining. Electrical discharge machining is particularly advantageous in industrial applications where precisely controlled random surface textures on these alloys are required. However, despite the industrial significance, research on the electrical discharge machining process of copper-nickel-silicon-chromium alloys is scarce. Therefore, the current work aims to address this research gap by conducting an experimental investigation of the random surfaces generated on copper-nickel-silicon-chromium alloy components after the die-sinking electrical discharge machining process through a comprehensive three-dimensional surface topography analysis. Three-dimensional surface topography parameters overcome the drawbacks of two-dimensional roughness parameters by considering the majority of surface points. This work investigates the effects of input factors, including electrode material, dielectric fluid material, flushing condition, and current on nearly all relevant areal texture (3D) parameters. ANOVA is performed to study the level of significance of each input parameter. The regression analyses reveal that current is the most si

关键词： Beryllium powder metallurgy

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Unassisted photoelectrochemical CO_(2)reduction by employingⅢ-Ⅴphotoelectrode with 15%solar-to-fuel efficiency

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Carbon Energy 2025年第3期7卷 1-10页

作者： Karthik Peramaiah Purushothaman Varadhan Vinoth Ramalingam Bilawal Khan Pradip Kumar Das Hao Huang Hui-Chun Fu Xiulin Yang Vincent Tung Kuo-Wei Huang Jr-Hau He Chemistry Program Center for Renewable Energy and Storage Technologies(CREST)and Division of Physical Science and EngineeringKing Abdullah University of Science and Technology(KAUST)ThuwalSaudi Arabia Institute of Sustainability for Chemicals Energyand Environment(ISCE2)Agency for ScienceTechnologyand Research(A*STAR)Singapore School of Computing Engineering and TechnologyRobert Gordon UniversityAberdeenUK Department of Materials Science and Engineering City University of Hong KongKowloonSARHong KongChina Guangxi Key Laboratory of Low Carbon Energy Materials School of Chemistry and Pharmaceutical SciencesGuangxi Normal UniversityGuilinChina Department of Chemical System and Engineering University of TokyoTokyoJapan

Solar-driven carbon dioxide reduction reaction(CO_(2)RR)provides an oppor tunity to produce value-added chemical feedstocks and ***,achieving efficient and stable photoelectrochemical(PEC)CO_(2)RR into selec tive products is challenging owing to the difficulties associated with the optical and the electrical configuration of PEC devices and electrocatalyst ***,we construct an efficient,concentrated sunlight-driven CO_(2)RR setup consisting of InGaP/GaAs/Ge triple-junction cell as a photoanode and oxide-derived Au(Ox-Au)as a cathode to perform the unassisted PEC CO_(2)*** one-sun illumination,a maximum operating current density of 11.5 mA cm^(-2) with an impressive Faradaic efficiency(FE)of~98%is achieved for carbon monoxide(CO)production,leading to a solar-to-fuel conversion efficiency of~15%.Under concentrated intensity of 10 sun,the photoanode records a maximum current density of~124 mAcm^(-2) and maintains~60%of FE for CO *** results demonstrate crucial advancements in usingⅢ-Ⅴbased photoanodes for concentrated PEC CO_(2)RR.

关键词： photoelectrochemical oxide derived Au concentrated sunlight selec tive products III V photoelectrode pec devices CO reduction solar fuel efficiency

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Experimental investigation of low-NOx H2 combustion using simultaneous Raman and LIF spectroscopy

Experimental investigation of low-NOx H2 combustion using si...

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AIAA science and Technology Forum and Exposition, AIAA SciTech Forum 2025

作者： Al Hadi, Z. Basnet, S. Marragou, S. Sharma, P. Schuller, T. Guiberti, T.F. Magnotti, G. Thuwal23955-6900 Saudi Arabia Mechanical Engineering Program Physical Science and Engineering Division King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia Institut de Mécanique des Fluides de T95T Université de Toulouse CNRS Toulouse France France

ISBN: (纸本)9781624107238

The global push toward decarbonization has positioned hydrogen as a key contender for clean energy applications. This study explores low-NOx hydrogen/air combustion in a lifted flame configuration using simultaneous 1D Raman and OH-LIF spectroscopy. High resolution measurements of temperature and species concentrations (H2, O2, and OH) provide crucial information on the structure of the flame and the stabilization mechanisms within a dual-swirl burner. The results reveal distinct inner and outer reaction fronts, each exhibiting unique combustion behaviors due to differences in gas composition, temperature, turbulence levels, and strain rates. The study focuses on the dynamics of the edge flame at the base of the outer reaction front, where air and hydrogen progressively mix along the flow axis. Detailed analysis of flow structure, flame dynamics, and properties at key locations highlights the interplay between flow and combustion processes. These findings provide a unique experimental data set for understanding the fundamental characteristics of swirled H2 flames, validating numerical models, and guiding the development of optimized low-NOx H2 combustion systems. © 2025, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

关键词： Flow structure

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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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Drop impact dynamics on hierarchically textured lubricant-infused surfaces

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physical Review Fluids 2025年第1期10卷 013604-013604页

作者： Biruk Teka Gidreta Michelle Huang Dan Daniel Solomon Adera Department of Mechanical Engineering University of Michigan Ann Arbor Michigan USA Division of Physical Sciences and Engineering King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia

After more than a century since Worthington's 1876 pioneering work, the topic of drop impact and the beautiful postimpact images that emerge continue to inspire scientists and the public alike due to the critical role that impact dynamics plays in cutting-edge engineering applications, with notable examples in spray cooling, spray coating, inkjet printing, pesticide dispersal, and the unlikely field of forensic science. For example, the pitting of turbine blades in steam power plants and the quality of solder bumps on printed circuit boards are directly affected by drop impact dynamics. Driven by recent advances in micro- and nanofabrication, which enabled coating of engineered surfaces with liquid films of controlled thickness, here, we characterize water drop impact dynamics (spreading, retraction, and breakup mechanism) on hierarchically textured silicon micropillars and microholes coated with a few microns thick of lubricant film. We observe that the droplet impact dynamics on overlubricated surfaces is invariant with the surface texture; specifically, micropillars and microholes with the same solid fraction exhibit similar postimpact dynamics. Our experiments show that there is an optimum lubricant layer thickness (≈3−5µm) that maximizes drop breakup and splashing mechanism. Additionally, we observe increased suppression of drop splashing and breakup with lubricant viscosity, which we attribute to viscous dissipation in the wetting ridge. Our experiments also show enhanced drop splashing intensity when the density difference between the drop and lubricant oil increases, suggesting the role of hydrodynamic instability in postimpact dynamics. The new insights gained from this work improve current understanding by informing the relevant material properties and dynamical behaviors of the impacting drop that can be tuned to either suppress or enhance impact-induced drop splashing.

关键词： Steam power plants

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Enhanced Bio-Oil Production from Nannochloropsis Algae via Catalytic Liquefaction: Synthesis and Application of Iron-based Magnetically Recoverable Catalysts

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BioResources 2025年第2期20卷 2745-2764页

作者： Nirmala, Narasiman Arun, Jayaseelan Kumar, Sivaperumal Sanjay Jayamani, Manivannan Sureshkumar, Kumar Jawhari, Ahmed Hussain Palanisamy, Sivasubramanian Ali, Syed Kashif Al-Farraj, Saleh A. Centre for Waste Management Sathyabama Institute of Science and Technology Jeppiaar Nagar Tamil Nadu Chennai600119 India Centre of Excellence for Energy Research Sathyabama Institute of Science and Technology Jeppiaar Nagar Tamil Nadu Chennai600119 India Department of Mechanical Engineering Kalasalingam Academy of Research and Education Tamil Nadu Krishnankoil626126 India Department of Electronics and Communication Engineering Koneru Lakshmaiah Education Foundation Guntur District Andhra Pradesh Vaddeswaram522302 India Department of Physical Sciences Chemistry Division College of Science Jazan University P.O. Box.114 Jazan45142 Saudi Arabia Department of Mechanical Engineering PTR College of Engineering and Technology Austinpatti Tamil Nadu Madurai625008 India Department of Physical Sciences Chemistry Division College of Science Jazan University Jazan45142 Saudi Arabia Nanotechnology Research Unit College of Science Jazan University Jazan45142 Saudi Arabia Department of Zoology College of Science King Saud University Riyadh Saudi Arabia

Magnetically recoverable iron-based catalysts were developed, with the goal of being cost-effective, reusable, and environmentally friendly. The use of iron-based magnetically recoverable catalyst enhances the catalytic process efficiency for the enhanced bio-oil yield and quality compared to non-catalytic and conventional catalytic methods. The present study aimed to evaluate the hydrothermal liquefaction (HTL) of Nannochloropsis sp. in the presence of Fe3O4 nanostructures for enhanced bio-oil production. The use of a magnetic-supported catalyst that is low-cost, safe, and can be reused many times without requiring a regeneration step (by retrieving it magnetically from the solid material) can serve as a novel strategy to be used at an industrial scale. The maximum bio-oil yield 31.4% was obtained with a Fe3O4 catalyst dosage of 0.3 g at temperatures of 300 °C and biomass to solvent ratio of 100 g/L, respectively. The compositional analysis of the produced bio-oil was performed and showed notable characteristics for biofuel application. The synthesized Fe3O4 catalyst was recyclable for up to five repeated cycles and a fluctuated bio yield was achieved for the last three cycles of procreation capability for HTL of Nannochloropsis sp. Further improvisation in designing the next generation magnetically recoverable catalyst with improved stability, efficiency will pay wave way for cost–effective and scalable bio-oil production systems. © 2025, North Carolina State University. All rights reserved.

关键词： Algae

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Negative PO3-implanted bionic ion transport channels for promoting Li-S battery

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science China Chemistry 2025年

作者： Wenhuan Huang Shun Wang Xuehan Hou Yanan Zhang Xingxing Zhang Yaoxiao Zhao Xilang Jin Huabin Zhang Fei Wang Jian Zhang Key Laboratory of Chemical Additives for China National Light Industry College of Chemistry and Chemical EngineeringShaanxi University of Science and Technology School of Materials and Chemical Engineering Xi'an Technological University Chemistry Program Physical Science and Engineering Division King Abdullah University of Science and Technology State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences

Lithium-sulfur （Li-S） battery,as a promising next-generation high-energy-density battery,suffers from lithium polysulfides（LPSs） shuttle and Li dendrites *** crystalline framework-based membranes as separator can effectively absorb and restrain LPSs but without precise structural design principal exploration and mechanism ***,bio-inspired 1D oriented lithium-ion transport channels with molecular negatively charged PO3（-1） have been developed in hybrid tetrazole frameworks for promoting the transmission of Li+*** theoretical calculations and in situ spectroscopy demonstrated the higher binding energy and inhibited diffusion of LPSs in *** assembled PP@PO3Janus separator in Li-S coin cell delivered a high initial capacity of 1410.9 mAh g-1at 0.1 C and a low attenuation rate of 0.038%per cycle over 500 cycles at 5 ***,the high capacities of 862,542 and 409 mAh g-1based on high-sulfur-loading cathodes of 2.6,3.8 and 5.0 mg cm-2at0.5 C were achieved,***,the punch battery of PO3@PP separator with S-cathode of 1.2 mg cm-2has been developed for demonstrating its potentials commercial application,which displays impressive capacity of 873.4 mAh g-1with the retention of～78.9%over 50 cycles.

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