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Graphene origami structures with superflexibility and highly tunable auxeticity

physical Review B 2020年第17期102卷 174106-174106页

作者： Duc Tam Ho Sung Youb Kim Udo Schwingenschlögl Physical Science and Engineering Division King Abdullah University of Science and Technology Thuwal 23955-6900 Saudi Arabia Department of Mechanical Engineering Ulsan National Institute of Science and Technology Ulsan 44919 South Korea

The two-dimensional structure of graphene makes it difficult to realize flexibility and auxeticity (negative Poisson's ratio) in graphene-based structures. Using molecular dynamics simulations, we demonstrate for graphene origami structures effective tuning of both the flexibility and Poisson's ratio through the geometry, including the potential to combine superflexibility with a highly tunable negative Poisson's ratio in contrast to any existing graphene-based structure. Auxeticity even can be achieved under large applied strain, both tensile and compressive.

关键词： Shear deformation Flexible electronics Graphene Molecular dynamics

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Influence of Highly Asymmetric Pore Structure on Capillary Bonding of Porous Membranes

SSRN

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SSRN 2022年

作者： Martinez, Jaylene Fan, Shouhong Rabade, Salil Blevins, Adrienne K. Fung, Kieran Killgore, Jason P. Perez, Stefano Berti Youngbear, Kathy Carbrello, Christina Foley, Sean Ding, Xiaoyun Long, Rong Castro, Robert Ding, Yifu Membrane Science Engineering and Technology Center Paul M. Rady Mechanical Engineering University of Colorado at Boulder BoulderCO80309-0427 United States Material Science & Engineering Program University of Colorado at Boulder BoulderCO80309 United States Applied Chemicals and Materials Division National Institute of Standards and Technology BoulderCO80305 United States MilliporeSigma 80 Ashby Rd. BedfordMA01730 United States

Reliable bonding of high-performance membranes onto polymeric supporting structures is critical for capitalizing their potentials within practical applications. The successful bonding typically requires infiltration of the membrane pores by a thermoplastic polymer, driven by capillary pressure and/or external pressure. In this work, we systematically examine the capillary infiltration of a polypropylene (PP) within polyethersulfone (PES) membranes with a highly asymmetric pore structure, a nominal pore size of 20 nm, and varying degrees of hydrophilicity. Most significantly, the infiltration kinetics was strongly influenced by the asymmetric pore structure in two aspects: (1) the time to achieve full infiltration from the large-pore side was approximately 4x that from the tight-pore side;(2) When bonding from the tight-pore side, the infiltration depth, L(t) showed L (t) ~ t 1.6, instead of characteristic L (t) ~ t 0.5. Such an acceleration in infiltration rate over time was successfully modelled with the Cai model using depth-dependent pore size that captures the asymmetric pore structure. Furthermore, chemical modification reduced initial infiltration rate only, which is attributed to the reduction in surface porosity. No significant difference in infiltration kinetics at the later stage was observed. mechanical integrity tests of the bonded samples display complex debonding behaviors including complete peeling, incomplete peeling, and complete membrane failure. The peel force corresponding to membrane failure appeared larger than other two debonding modes, all of which showed insignificant dependence on the membrane chemistry or infiltration depth. Post-mortem analysis of the completely peeled sample showed PP nanofibers were pulled out of the PES membranes during debonding, emphasizing relatively weak mechanical interlocking due to the low surface porosity. © 2022, The Authors. All rights reserved.

关键词： Pore structure

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Purification of ytterbium using a cationic resin

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Results in Surfaces and Interfaces 2025年 19卷

作者： Moura, Pedro A.S. Grande, Carlos A. Laboratory of Intensification of Materials and Processes (IMAP) 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 (KAUST) Thuwal 23955-6900 Saudi Arabia

The growing demand for high quantities of Rare Earth Elements (REE) led to the need for novel processes for their recovery and purification. Adsorption is a promising technique for purifying REE as it eliminates the use of hazardous chemicals. This work evaluates the use of the commercial polymeric resin Dowex 50W-X8 for polishing a ytterbium (Yb) stream contaminated with other REE present when recycling neo-magnets. Adsorption equilibrium isotherms and breakthrough curves of different REE (Yb, La, Nd and Er) and binary mixtures were measured. The adsorption capacity at concentrations of 300 mg L⁻¹ ranges from 179 to 205 mg g⁻¹ following the order Er > Nd > Yb > La. The steepness of the isotherms follows a different order: Nd > Er > La > Yb, indicating that Yb will be the less adsorbed REE in a mixture. A mathematical model was fitted to single component data and was successfully used to predict the behavior of binary breakthrough curves. © 2025 The Authors

关键词： Adsorption Breakthrough curves Diffusion Modelling Rare-earth elements

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Optimizing electrochemical removal of perfluorooctanoic acid in landfill leachate using ceramic carbon foam electrodes by coupling CFD simulation and reactor design

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Chemosphere 2025年 376卷 144282页

作者： Pierpaoli, Mattia Jakóbczyk, Pawel Szopińska, Malgorzata Ryl, Jacek Giosué, Chiara Wróbel, Maciej Strugala, Gabriel Luczkiewicz, Aneta Fudala-Książek, Sylwia Bogdanowicz, Robert Faculty of Electronics Telecommunications and Informatics Department of Metrology and Optoelectronics Gdańsk University of Technology 11/12 Gabriela Narutowicza Street Gdańsk80-233 Poland Faculty of Civil and Environmental Engineering Department of Environmental Engineering Technology Gdańsk University of Technology 11/12 Gabriela Narutowicza Street Gdańsk80-233 Poland Faculty of Applied Physics and Mathematics Division of Electrochemistry and Surface Physical Chemistry Gdańsk University of Technology 11/12 Gabriela Narutowicza Street Gdańsk80-233 Poland Università Politecnica Delle Marche Via Brecce Bianche 12 Ancona60131 Italy Faculty of Mechanical Engineering and Ship Technology Department of Materials Science and Technology Gdańsk University of Technology 11/12 Gabriela Narutowicza Street Gdańsk80-233 Poland Faculty of Civil and Environmental Engineering Department of Sanitary Engineering Gdańsk University of Technology 11/12 Gabriela Narutowicza Street Gdańsk80-233 Poland

Perfluorooctanoic acid (PFOA), a persistent and bioaccumulative pollutant classified as a 'forever chemical', poses a global environmental and health risk due to its widespread use and resistance to degradation. The development of effective and efficient removal technologies is crucial to mitigate its long-term impacts. In this study, we present a novel approach to address the growing concern of emerging contaminants, particularly PFOA, in landfill leachate. We investigate the use of ceramic carbon foam electrodes (CCFE) as a cost-effective and efficient alternative to traditional electrode materials for the electrochemical degradation of PFOA. Computed microtomography was used to reconstruct the actual three-dimensional geometries of the samples from which porosities were calculated. We also coupled computational fluid dynamics simulations of the actual geometries and optimized the working conditions to minimize pressure drop and improve treatment efficiency. Our design significantly reduces energy requirements by operating at lower potentials, a critical factor in sustainable waste management practices. The optimized CCFE system demonstrated superior performance in the degradation of PFOA in landfill leachate, offering a promising solution for the treatment of emerging contaminants. This study not only provides a viable method for mitigating the environmental impact of PFOA but also sets a precedent for the development of low-energy, high-efficiency treatment technologies for various persistent pollutants. In addition, the proposed solution, as part of closed-loop water systems, will enhance water reuse and recycling, thereby preserving and regenerating natural water bodies. © 2025 Elsevier Ltd

关键词： Leachate treatment

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Designing the pressure-dependent shear modulus using tessellated granular metamaterials

arXiv

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arXiv 2023年

作者： Zhang, Jerry Wang, Dong Jin, Weiwei Xia, Annie Pashine, Nidhi Kramer-Bottiglio, Rebecca Shattuck, Mark D. O’Hern, Corey S. Department of Mechanical Engineering & Materials Science Yale University New HavenCT06520 United States Benjamin Levich Institute and Physics Department The City College of New York New YorkNY10031 United States Department of Physics Yale University New HavenCT06520 United States Department of Applied Physics Yale University New HavenCT06520 United States Integrated Graduate Program in Physical and Engineering Biology Yale University New HavenCT06520 United States

Jammed packings of granular materials display complex mechanical response. For example, the ensemble-averaged shear modulus 〈G〉 increases as a power-law in pressure p for static packings of soft spherical particles that can rearrange during compression. We seek to design granular materials with shear moduli that can either increase or decrease with pressure without particle rearrangements even in the large-system limit. To do this, we construct tessellated granular metamaterials by joining multiple particle-filled cells together. We focus on cells that contain a small number of bidisperse disks in two dimensions. We first study the mechanical properties of individual disk-filled cells with three types of boundaries: periodic boundary conditions (PBC), fixed-length walls (FXW), and flexible walls (FLW). Hypostatic jammed packings are found for cells with FLW, but not in cells with PBC and FXW, and they are stabilized by quartic modes of the dynamical matrix. The shear modulus of a single cell depends linearly on p. We find that the slope of the shear modulus with pressure, λc c > 0, as well as λc © 2023, CC BY.

关键词： Elastic moduli

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mechanical Plasticity of Cell Membranes Enhances Epithelial Wound Closure

arXiv

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arXiv 2023年

作者： Ton, Andrew T. MacKeith, Arthur K. Shattuck, Mark D. O'Hern, Corey S. Department of Physics Yale University New HavenCT06520 United States Integrated Graduate Program in Physical and Engineering Biology Yale University New HavenCT06520 United States Department of Mechanical Engineering & Materials Science Yale University New HavenCT06520 United States Benjamin Levich Institute and Physics Department The City College of New York New YorkNY10031 United States Department of Applied Physics Yale University New HavenCT06520 United States

During epithelial wound healing, cell morphology near the healed wound and the healing rate vary strongly among different developmental stages even for a single species like Drosophila. We develop deformable particle (DP) model simulations to understand how variations in cell mechanics give rise to distinct wound closure phenotypes in the Drosophila embryonic ectoderm and larval wing disc epithelium. We find that plastic deformation of the cell membrane can generate large changes in cell shape consistent with wound closure in the embryonic ectoderm. Our results show that the embryonic ectoderm is best described by cell membranes with an elasto-plastic response, whereas the larval wing disc is best described by cell membranes with an exclusively elastic response. By varying the mechanical response of cell membranes in DP simulations, we recapitulate the wound closure behavior of both the embryonic ectoderm and the larval wing disc. © 2023, CC BY-NC-ND.

关键词： Cytology

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Numerical Evaluation of Low-Head Inverted Cross-Flow Turbine Design Methodology: A Comprehensive Study

SSRN

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SSRN 2023年

作者： Ha, Hojin Ham, Sangwoo Ehsan, Adeeb Lee, Jeong Wan Interdisciplinary Program in Biohealth-Machinery Convergence Engineering Kangwon National University 1 Kangwondaehak-gil Gangwon-do Chuncheon-si24341 Korea Republic of Division of Mechanical & Biomedical Mechatronics and Materials Science and Engineering Kangwon National University 1 Kangwondaehak-gil Gangwon-do Chuncheon-si24341 Korea Republic of Kangwon Institute of Inclusive Technology Kangwon National University 1 Kangwondaehak-gil Gangwon-do Chuncheon-si24341 Korea Republic of

In this study, we aim to address the challenges of micro-hydropower generation in low-head environments. The authors reviewed and assessed various factors affecting the feasibility of micro-hydro systems, such as geographical constraints, construction costs, and grid connectivity. To overcome the limitations of conventional hydro turbines in such conditions, the authors proposed a novel cross-flow turbine. Initially, they designed and analyzed an inverted cross-flow turbine based on design rules established by previous researchers and performed numerical analyses. Four steps parametric studies were conducted to achieved optimum turbine values, such as runner diameter ratio and the number of blades, considering the maximum efficiency point from the previous step. The best efficiency point of the optimized design turbine was 72.92 % at a runner rotational speed of 170 RPM with a 0.75 runner diameter ratio and 35 blades. To validate the optimized design, the authors compared it with the initial design using hill charts and numerical values obtained from parametric studies. Overall, this research demonstrates the usefulness of computational fluid dynamics simulations and parametric studies in optimizing the design of an inverted cross-flow turbine under low head conditions. © 2023, The Authors. All rights reserved.

关键词： Computational fluid dynamics

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Pre-treatment optimization to reduce membrane fouling during produced water treatment with an integrated FO-MD system

Science Talks

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science Talks 2025年 14卷

作者： Muhammad Saqib Nawaz Sofiane Soukane Muhammad Bilal Asif Veerabhadraiah Gudideni Sultan Alrubaish Noreddine Ghaffour Environmental Sciences and Engineering Program Division of Biological and Environmental Sciences and Engineering (BESE) King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia Physical Sciences and Engineering Division (PSE) King Abdullah University of Science and Technology (KAUST) Thuwal 23955-6900 Saudi Arabia Energy Systems Division Process & Control Systems Department Saudi Aramco Dhahran Saudi Arabia

During oil exploration, fresh water that is injected into underground reservoirs returns to the surface loaded with hydrocarbons, salts, and other contaminants. This complex solution is typically known as produced water (PW). Generally, different PW streams are generated at a given site, which, after suitable treatment, are sent for re-injection for enhanced oil recovery or to disposal wells. However, there is a potential for water recovery from this hypersaline contaminated stream. Forward osmosis (FO) and membrane distillation (MD) are two low-pressure membrane treatment technologies successfully used in a single hybrid system for PW treatment. During operation, the key foulants on the FO membrane were CaSiO 3 , CaSO 4 , and NaCl, while for MD, they were SiO 2 and CaSO 4 plus emulsified oil, causing pore clogging. Some foulants were tightly bound and not removed by osmotic backwashing or hydraulic flushing, thus requiring pre-treatment. Different pre-treatment techniques, like ion exchange resins and polymeric and ceramic membrane-based ultrafiltration (UF), were assessed in this study. The resins were able to remove bivalent metallic ions successfully from lower concentration streams only and thus caused an increase in FO flux and a reduction in MD flux by disturbing the FO-MD system equilibrium. The higher concentrations of resins and chemicals required for their regeneration make them unsuitable for such applications. On the contrary, PW pre-treated with polymeric and ceramic UF membranes led to increased FO and MD fluxes without any chemical requirement and proved suitable for pre-treatment.

关键词： Pre-treatment Produced water Ion-exchange resins Ultrafiltration Forward osmosis Membrane distillation

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Transferable screened range-separated hybrid functionals for electronic and optical properties of van der Waals materials

arXiv

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arXiv 2023年

作者： Camarasa-Gómez, María Ramasubramaniam, Ashwin Neaton, Jeffrey B. Kronik, Leeor Department of Molecular Chemistry and Materials Science Weizmann Institute of Science Rehovoth7610001 Israel Department of Mechanical and Industrial Engineering University of Massachusetts Amherst AmherstMA01003 United States Materials Science and Engineering Graduate Program University of Massachusetts Amherst AmherstMA01003 United States Department of Physics University of California BerkeleyCA94720 United States Materials Sciences Division Lawrence Berkeley National Laboratory BerkeleyCA94720 United States Kavli Energy NanoSciences Institute at Berkeley University of California BerkeleyCA94720 United States

The accurate description of electronic properties and optical absorption spectra is a long-standing challenge for density functional theory. Recently, the introduction of screened range-separated hybrid (SRSH) functionals for solid-state materials has allowed for the calculation of fundamental band gaps and optical absorption spectra that are in very good agreement with many-body perturbation theory. However, since solid-state SRSH functionals are typically tuned to reproduce the properties of bulk phases, their transferability to low-dimensional structures, which experience substantially different screening than in the bulk, remains an open question. In this work, we explore the transferability of SRSH functionals to several prototypical van der Waals materials, including transition-metal sulfides and selenides, indium selenide, black phosphorus, and hexagonal boron nitride. Considering the bulk and a monolayer of these materials as limiting cases, we show that the parameters of the SRSH functional can be determined systematically, using only the band-edge quasiparticle energies of these extremal structural phases as fitting targets. The resulting SRSH functionals can describe both electronic bandstructures and optical absorption spectra with accuracy comparable to more demanding ab initio many-body perturbation theory (GW and Bethe-Salpeter equation) approaches. Selected examples also demonstrate that the SRSH parameters, obtained from the bulk and monolayer reference structures, display good accuracy for bandstructures and optical spectra of bilayers, indicating a degree of transferability that is independent of the fitting procedure. Copyright © 2023, The Authors. All rights reserved.

关键词： Transition metals

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Electric Field Emission in GdNiO3 Microflower

SSRN

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SSRN 2024年

作者： Karmakar, Subrata Parey, Vanshree Mistari, Chetan D. Hamid, Md Abdul Emu, Injamamul Hoque Halim, Md Abdul Sanyal, Gopal Chakraborty, Brahmananda More, M.A. Droopad, Ravi Haque, Ariful Ingram School of Engineering Texas State University San MarcosTX78666 United States Institute of Chemical Research of Catalonia The Barcelona Institute of Science and Technology Av. Països Catalans 16 Tarragona43007 Spain Department of Physics Savitribai Phule Pune University Maharashtra Pune411007 India Mechanical Metallurgy Division Bhabha Atomic Research Centre Trombay Mumbai400085 India High Pressure and Synchrotron Radiation Physics Division Bhabha Atomic Research Centre Trombay Mumbai400085 India Homi Bhabha National Institute Anushaktinagar Mumbai400094 India Materials Science Engineering & Commercialization Program Texas State University San MarcosTX78666 United States

GdNiO3 microflowers were synthesized by hydrothermal method with unit sizes of about 2.2-3.5 μm and petal sizes of ~75-100 nm. The X-ray diffraction pattern (XRD) and Raman spectra reveal an orthorhombic crystal structure with the space group Pbnm and various Raman active vibrational modes i.e., Ag, B1g, B2g associated with rare earth nickelates. The total density of states (TDOS) was calculated by density functional theory (DFT) study using a hybrid functional (HSE06) and the volume of TDOS near the Fermi level confirms the semiconducting nature of GdNiO3 with band gap ~0.688 eV. The local bulk work function (φ) was estimated theoretically at ~5.35 eV from DFT calculations which is one of the essential parameters for the field enhancement factor (β). Field emission current density (J) vs. applied electric field (E) divulges a low turn-on field (Eto)~4.6 V/μm@1 μA/cm2 and a threshold field (Eth)~5.2 V/μm@10 μA/cm2 respectively. The Fowler-Nordheim (F-N) model was introduced to calculate β ~1637 and long-term field emission current stability was observed experimentally > 4 h at the preset values of current 2 μA and 10 μA, respectively. The easy preparedness, low turn-on field, and long-term current stability without significant decay suggest this material to be an efficient electron field emitting material in the rare-earth nickelates series. © 2024, The Authors. All rights reserved.

关键词： Rare earths

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