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

Procedia CIRP 2025年 132卷 104-109页

作者： Ruslan Melentiev Ahmed Wagih Bram van der Heijden Gilles Lubineau Carlos A. Grande Advanced Membranes & Porous Materials Center. King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia KAUST Catalysis Center. King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia Mechanical Engineering Program Physical Sciences and Engineering Division King Abdullah University of Science and Technology (KAUST) Saudi Arabia Mechanics of Composites for Energy and Mobility Lab King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia Chemical Engineering Program. Physical Science and Engineering Division King Abdullah University of Science and Technology

Metamaterials are a class 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 surpasses 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-stainless-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 compression-induced rotation in steel twist metamaterials and highlight their sensitivity to manufacturing defects. Download: Download video (753KB) Download: Download video (2MB) Download: Download video (4MB)

关键词： Additive manufacturing sintering stainless steel metamaterials mechanical properties

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Lithography-based additive manufacturing of steel metamaterials: effect of sintering temperature on shape distortion, microstructure and mechanical properties

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Procedia CIRP 2025年 132卷 80-85页

作者： Ruslan Melentiev Ahmed Wagih Gilles Lubineau Carlos A. Grande Advanced Membranes & Porous Materials (AMPM) Center. King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia KAUST Catalysis Center (KCC). King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia Mechanical Engineering Program Physical Sciences and Engineering Division King Abdullah University of Science and Technology (KAUST) Saudi Arabia Mechanics of Composites for Energy and Mobility Lab King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia Chemical Engineering Program. Physical Science and Engineering (PSE) Division King Abdullah University of Science and Technology

Lithography metal manufacturing (LMM) is an emerging sinter-based additive manufacturing (AM) technology for support-free 3D printing of extremely complex parts with micrometric resolution on a decimeter scale. Although the printing phase of LMM is well-established, the sintering stage is challenging due to either high porosity or melting-induced deformation, particularly in thin-walled lattices and metamaterials. This study investigates the effects of sintering temperature on shape distortion, surface morphology, chemistry, porosity, microstructure, and mechanical properties of 316L stainless steel auxetic metamaterials 3D printed using LMM and sintered in a furnace customized for precise temperature control. Our results show that the fully dense grain microstructure with high plasticity can be sintering within 1300 – 1325 °C range. Going beyond this temperature results in shape distortion and embrittlement of the steel metamaterials. The previously recommended range of sintering temperatures for 316L steel, 1360 - 1380 °C need revision.

关键词： Additive manufacturing (AM) Debinding Sintering Metal Metamaterials Mechanical properties

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Flexible refractory castables based on the Al2O3-MgO-TiO2 system

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Ceramics International 2025年

作者： Reitmann, B. Borges, O.H. Falsetti, L.O.Z. Pagliosa Neto, C. Pandolfelli, V.C. Federal University of São Carlos Graduate Program in Materials Science and Engineering São Carlos Brazil São Carlos Brazil RHI Magnesita Research and Development Center Contagem Brazil

Toughening by in-situ phase formation is highly desired for high-performance refractories, as it enhances their thermomechanical properties (e.g. thermal shock damage resistance). For this purpose, pseudobrookite and intermediary spinels are promising phases due to their thermal expansion mismatch, resulting in self-microcracking. Aiming to develop highly flexible refractory castables, compositions based on the Al2O3-MgO-TiO2 system were formulated with the aid of computational thermodynamics. Of the most promising compositions, five of them were experimentally produced and had their thermomechanical and physical properties assessed by X-ray diffraction, in-situ elastic modulus, thermal shock damage analysis (ΔT = 1000 °C) and scanning electron microscopy. Results pointed out that small titania contents led to a positive effect on microstructure densification, improving the mechanical performance of the refractories and generation of phases that induce microcracking upon cooling, enhancing the thermal shock damage resistance. Nevertheless, an excess of TiO2 led to extensive cracking and cohesion loss in the refractory matrix. © 2025

关键词： Microcracking

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Effects of Nitrogen Fertilizer Types on the Uptake and Translocation of PFAS and Metabolomic Activities of Hydroponically Cultivated Lettuce (Lactuca sativa)

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Journal of Agricultural and Food Chemistry 2025年第18期73卷 10907-10913页

作者： Adu, Olatunbosun Duza, Syeda Sharmin Sharma, Virender K. Ma, Xingmao Department of Water Management and Hydrological Science Texas A&M University College StationTX77843 United States Program for the Environment and Sustainability Department of Environmental and Occupational Health School of Public Health Texas A&M University 212 Adriance Lab Rd. 1266 TAMU College StationTX77843 United States Department of Chemical Environmental and Materials Engineering University of Miami Coral GablesFL33146 United States Department of Civil and Environmental Engineering Texas A&M University College StationTX77843 United States

Increasing evidence is showing that per- and polyfluoroalkyl substance (PFAS) replacing compounds are not as safe as they were assumed. This study investigated the plant uptake of two most prevalent PFAS, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic (PFOS) and their replacing compounds, hexafluoropropylene oxide dimer acid (HFPO-DA or GenX) and 6:2 chlorinated polyfluoroalkyl ether sulfonates (Cl-PFESAs) (6:2 Cl-PFAES) by hydroponically grown lettuce in the presence of different nitrogen fertilizers including ammonium sulfate ((NH4)2SO4), potassium nitrate (KNO3), and urea in a growth chamber. Interestingly, (NH4)2SO4 significantly increased GenX uptake in lettuce shoots by ∼108% and KNO3 increased the uptake of PFOS and 6:2 Cl-PFAES by 267% and 395%, respectively, suggesting that the nitrogen fertilizer type has a marked impact on the plant uptake of PFAS and that this impact was PFAS-dependent. Our results also showed that (NH4)2SO4 generally resulted in higher PFAS root to shoot transfer than the other two types of nitrogen fertilizers. Metabolomic analysis revealed that amino acids, nucleotides, and antioxidants are the major metabolites that were either significantly increased or decreased in the lettuce shoots. These results showed that nitrogen fertilization management can have a significant impact on PFAS plant uptake and transport, and the impact depends on the types of nitrogen fertilizer and PFAS compounds. © 2025 The Authors. Published by American Chemical Society.

关键词： Urea fertilizers

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A Runaway Electron Avalanche Surrogate for Partially Ionized Plasmas

arXiv

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arXiv 2025年

作者： Arnaud, Jonathan S. McDevitt, Christopher J. Tang, Xian-Zhu Nuclear Engineering Program Department of Materials Science and Engineering University of Florida GainesvilleFL32611 United States Theoretical Division Los Alamos National Laboratory Los AlamosNM87545 United States

A physics-constrained deep learning surrogate that predicts the exponential "avalanche" growth rate of runaway electrons (REs) for a plasma containing partially ionized impurities is developed. Specifically, a physics-informed neural network (PINN) that learns the adjoint of the relativistic Fokker-Planck equation in steady-state is derived, enabling a rapid surrogate of the RE avalanche for a broad range of plasma parameters, motivating a path towards an ML-accelerated integrated description of a tokamak disruption. A steady-state power balance equation together with atomic physics data is embedded directly into the PINN, thus limiting the PINN to train across physically consistent temperatures and charge state distributions. This restricted training domain enables accurate predictions of the PINN while drastically reducing the computational cost of training the model. In addition, a novel closure for the relativistic electron population used when evaluating the secondary source of REs is developed that enables improved accuracy compared to a Rosenbluth-Putvinski source. The avalanche surrogate is verified against Monte Carlo simulations, where it is shown to accurately predict the RE avalanche growth rate across a broad range of plasma parameters encompassing distinct tokamak disruption scenarios. © 2025, CC BY.

关键词： Fokker Planck equation

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Porous Poly(vinylidene fluoride-co-hexafluoropropylene)/copper oxide nanocomposite membranes for piezoelectric strain sensing

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Discover Applied sciences 2025年第5期7卷 1-17页

作者： Al-Ejji, Maryam Promi, Tamanna Sangor, Farah Al-Awa, Zinab Bonthula, Sumalatha Radhika, V. Ponnamma, Deepalekshmi Center for Advanced Materials Qatar University Doha Qatar Department of Biological and Environmental Sciences Qatar University Doha Qatar Department of Chemical Engineering University of Calicut Thenhipallam India Materials Science and Technology Program Department of Mathematics Statistics and Physics College of Arts and Sciences Qatar University Doha Qatar

The emerging field of porous piezoelectric strain sensors attracted a wide range of applications in healthcare monitoring, wearable electronics, and other dynamic applications due to their durability, high sensitivity, and real-time monitoring. This study presents the development of porous poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)/copper oxide (CuO) nanocomposite membranes for piezoelectric strain sensing. The morphology and the dispersion of CuO nanoparticles and nanofibers in PVDF piezoelectric films with different nano-CuO contents are studied by X-ray diffraction, Fourier transform infrared spectrum, scanning electron microscopy and dielectric studies. The PVDF-HFP acts as a scaffold, allowing ions to flow within the porous percolated channels, resulting in a highly robust membrane with desired dielectric properties. The DMA studies enhanced the strain sensing performance of the 3.5 and 7 wt.% CuO nanofibers loaded with PVDF-HFP membranes compared with the 3.5 and 7 wt.% CuO nanoparticles and pristine membranes. The dielectric properties of the composites also showed high storage values for the CuO/PVDF-HFP samples compared to the pristine polymer. Moreover, the surface water contact angles of the membranes have slightly increased after loading the nanomaterial into the PVDF-HFP matrix, which strongly influenced the surface energies, indicating hydrophobicity. The current study, thus, demonstrates the piezoelectric strain sensing devices made from PVDF-HFP/CuO nanofibers for humid atmospheres.

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Multi-Component Lubricant Additives Derived from Pickering Emulsion-Templated Ionic Liquid Microcapsules

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Journal of Molecular Liquids 2025年 422卷

作者： Yan, Jieming Lak, Sarah N. Pentzer, Emily B. Mangolini, Filippo Texas Materials Institute The University of Texas at Austin AustinTX78712 United States Materials Science and Engineering Program The University of Texas at Austin AustinTX78712 United States Department of Chemistry Texas A&M University College StationTX77843 United States Department of Materials Science and Engineering Texas A&M University College StationTX77843 United States Walker Department of Mechanical Engineering The University of Texas at Austin AustinTX78712 United States

Room-temperature ionic liquids (RTILs) have emerged as potential next-generation lubricants owing to their unique physico-chemical properties and promising lubricating behavior. However, their implementation in tribological applications has partly been hindered by their negligible solubility in hydrocarbon fluids. Here, encapsulated ionic liquids (ENILs) with a core of 1-hexyl-3-imidazolium bis(trifluoromethylsulfonyl)imide ([HMIM][TFSI]) and a composite shell of polyurea/graphene oxide were prepared via Pickering emulsion-templated interfacial polymerization using two approaches, namely an RTIL-in-water emulsion stabilized with graphene oxide (GO) nanosheets ([HMIM][TFSI]/GO) and an RTIL-in-oil emulsion-stabilized with octadecylamine-functionalized GO nanosheets ([HMIM][TFSI]/C18-GO). The synthesized ENILs were successfully dispersed in polyalphaolefin (PAO) synthetic oil and used as additives to lubricate 52100 steel-vs.-52100 steel sliding contacts. Tribological tests provided evidence that the addition of [HMIM][TFSI]/C18-GO and [HMIM][TFSI]/GO ENILs to PAO could reduce friction and wear owing to the release of the encapsulated [HMIM][TFSI] at the sliding interface after the mechanical breakage of the shell material at the contact inlet, but only if a significant fraction of the ENILs has a diameter smaller than 20 µm. Comparison of these results with the outcomes of sliding experiments performed with PAO containing ENIL obtained by mini-emulsion polymerization with poly(ethylene glycol dimethacrylate-co-buytl methacrylate) (poly(EGDM-c-BMA)) shells highlights the role of the shell material in reducing friction. These outcomes not only demonstrate that multiple parameters (i.e., size distribution, shell material) affect the tribological performance of ENILs, but also pave the way towards further systematic investigations for optimizing ENILs to be used as additives in oil formulations. © 2025 Elsevier B.V.

关键词： Emulsification

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Current advances of biodegradable and biocompatible nanofiber-based materials for tissue engineering and drug delivery

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MRS Communications 2025年 1-17页

作者： Li, Zhiming Bhaskar, Nitu Erel-Akbaba, Gulsah Zhu, Yuhui Ge, Gang Park, Jinyoung Angadi, Kishan Duhoon, Achal Nguyen, Thanh Duc Department of Biomedical Engineering University of Connecticut Storrs USA Polymer Program Institute of Materials Science University of Connecticut Storrs USA Department of Pharmaceutical Biotechnology Faculty of Pharmacy Izmir Katip Celebi University Izmir Turkey Department of Mechanical Engineering University of Connecticut Storrs USA

Nanoscale fibrous materials of natural and synthetic polymers with high porosity, flexibility, biodegradability, biocompatibility, and functionality have garnered a lot of scientific attention and present exciting opportunities for regenerative medicine and drug delivery. The potential of developing scaffolds and drug delivery systems that can overcome current barriers in the fields of medicine and pharmacy is greatly expanded by the transformation and incorporation of nanofibers into free-standing nanomembranes, 3D scaffolds, actuators, transducers or sensors, which permits localized stimulation of target tissues, promotes proliferation, and enables controlled drug release over time. This review emphasizes innovative materials, fabrication techniques, and biomedical uses of synthetic and natural nanofiber-based biomaterials. Different from the previous reviews in the field, this work at best includes literature within the last 8 years to cover new exciting functional nanofibers (such as biodegradable electroactive nanofibers) and unique medical applications of these nanofiber materials. We highlight the use of a range of recent fabrication techniques (electrospinning, phase separation, and molecular self-assembly) to enhance the physicochemical and mechanical properties as well as (bio)compatibility of nanofibers for advanced drug delivery systems and tissue engineering applications. At the end, this article provides a future perspective on the advancement of biodegradable and biocompatible nanofibers for the fields of tissue engineering and drug delivery.

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Biogas and biohydrogen production using the main agricultural biomasses generated in Brazil: An integrative analysis to contribute to the implementation of energy decarbonization

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International Journal of Hydrogen Energy 2025年 137卷 190-201页

作者： Maele Costa dos Santos Willian Cezar Nadaleti Grzegozr Przybyla Jones Bittencourt Machado Environmental and Energy Engineering Lab – LEAE Engineering Center – CEng Postgraduation Program in Environmental Sciences - PPGCAmb The Federal University of Pelotas – UFPel Pelotas Rio Grande do Sul Brazil Post-graduation Program in Materials Science and Engineering - PPGCEM. The Federal University of Pelotas – UFPel Pelotas Rio Grande do Sul Brazil Department of Thermal Technology Silesian University of Technology Poland

The use of bioenergy feedstocks, agricultural and forest residues constitute a viable decarbonization design with regards to biofuel production. Nevertheless, aspects within agriculture that can be related to this process for instance, include: technology and infrastructure, policies, land use, environmental factors among others. Solving these challenges needs research, technological intervention, supportive policies and acclaimed association among agriculture and energy departments, especially considering that agricultural and forest residues are an abundant source of biomass which can be converted into renewable energy, for example, biogas and hydrogen. This study provides an assessment of the capacity for generating biogas and biohydrogen using the primary biomasses produced in Brazil's agricultural sector, specifically from rice, corn, soybeans, and wheat as alternative bioenergy resources. Data regarding production and waste creation were collected from the Statistical and Geographical Information of Brazilian Agriculture at the Institute of Geography and Statistics of Brazil and the Energy Research Company. Corn and Soybean straw showed the highest potentials for biohydrogen (PH) production, accounting to 6,67 E+09 m 3 /year and 5,56 E+09 m 3 /year respectively. The energy production using the generated biogas showed the most satisfactory results compared to biohydrogen, with the highest generation values of 222 TWh of energy for corn straw, 187 TWh for soybean straw. The total accumulated biogas and biohydrogen produced from the residual biomass of Brazil's four main permanent crops was approximately 8.25 E+10 and 1.33 E+10 m 3 /year, respectively. The generation of biogas and hydrogen holds significant potential for fostering a more sustainable energy future. By utilizing the unique advantages of these two methods—biogas as a waste-to-energy option and hydrogen as a clean and adaptable energy source—we can develop a more robust, varied, and low-carbon energy

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A Comprehensive Review on plant and animal fiber reinforced composites: Experimental and theoretical approaches to interfacial strength optimization and potential applications

Hybrid Advances

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Hybrid Advances 2025年 10卷

作者： Olanrewaju, Olajesu Oladele, Isiaka Oluwole Adelani, Samson Oluwagbenga Department of Materials Science and Engineering Iowa State University Ames IA United States Department of Metallurgical and Materials Engineering Federal University of Technology PMB Akure 704 Nigeria Centre for Nanomechanics and Tribocorrosion School of Metallurgy Chemical and Mining Engineering University of Johannesburg Johannesburg South Africa Materials Science and Engineering Program University of Colorado Boulder 80303 CO United States

Natural fiber-reinforced composites (NFRCs) have become vital in various engineering applications due to their exceptional properties and ease of manufacturing. Properties such as lightweight, sustainability, design flexibility, microstructure, durability, and advanced fabrication techniques have expanded their use across industries. Also, NFRCs are preferred because the extensive reliance on synthetic fibers presents significant challenges in recycling and waste management. Despite their excellent properties, NFRCs have three main challenges: fiber degradation, water degradation, and weak interfacial strength (incompatibility of fibers with the matrix). Consequently, research efforts have been directed at combating these challenges using different surface treatment techniques. However, research has been skewed towards experimental approaches for improving the interfacial strength in plant fiber polymer matrix composites (PMCs). Hence, there exists a dearth of information on the computational approaches for optimizing the interfacial properties of NFRCs. Hence, this review provides experimental and computational approaches (machine learning) for comprehensive optimizing strategies for different natural fibers (plant, animal, and microorganism) and matrices (polymers, metals, and ceramics). This review also highlights the importance of theoretical approaches and numerical modeling in analyzing and optimizing NFRCs. Finally, the review highlights recent advancements in NFRCs, their mechanical properties, potential applications, and future directions. © 2025 The Authors

关键词： Animal fiber Interfacial shear strength Machine-learning Natural fiber-reinforced composites Plant fiber

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